"Science, Faculty of"@en . "Earth, Ocean and Atmospheric Sciences, Department of"@en . "DSpace"@en . "UBCV"@en . "Winter, Lawrence Stephen"@en . "2008-04-24T21:23:52Z"@en . "2008"@en . "Doctor of Philosophy - PhD"@en . "University of British Columbia"@en . "The \u00E2\u0080\u0098giant\u00E2\u0080\u0099 Tambogrande volcanogenic massive sulphide (VMS) deposits within the Cretaceous Lancones basin of northwestern Per\u00C3\u00BA are some of the largest Cu-Zn-Au-Ag-bearing massive sulphide deposits known. Limited research has been done on these deposits, hence the ore forming setting in which they developed and the key criteria that permitted such anomalous accumulation of base-metal sulphides are not understood. \nBased on field relationships in the host volcanic rocks and U-Pb geochronology, the deposits formed during the early stages of arc development in the latest Early Cretaceous and were related to an extensional and arc-rift phase (~105-100 Ma, phase 1). During this time, bimodal, primitive basalt-dominant volcanic rocks were erupted in a relatively deep marginal basin. Phase 1 rhyolite is tholeiitic, M-type, and considered to have formed from relatively high temperature, small batch magmas. The high heat flow and extensional setting extant during the initial stages of arc development were essential components for forming a VMS hydrothermal system. The subsequent phase 2 (~99-91 Ma) volcanic sequence comprises more evolved mafic rocks and similar, but more depleted, felsic rocks erupted in a relatively shallow marine setting. Phase 2 is interpreted to represent late-stage arc volcanism during a waning extensional regime and marked the transition to contractional tectonism. \nThe Tambogrande deposits are particularly unusual amongst the \u00E2\u0080\u0098giant\u00E2\u0080\u0099 class of VMS deposits in that deposition largely occurred as seafloor mound-type and not by replacement of existing strata. Paleomorphology of the local depositional setting was defined by seafloor depressions controlled by syn-volcanic faults and rhyolitic volcanism. The depressions were the main controls on distribution and geometry of the deposits and, due to inherently confined hydrothermal venting, enhanced the efficiency of sulphide deposition.\nGeochemical and radiogenic isotope data indicate that the rhyolites in the VMS deposits were high temperature partial melts of the juvenile arc crust that had inherited the isotopic signatures of continental crust. Moreover, Pb isotope data suggest the metal budget was sourced almost wholly from mafic volcanic strata. Therefore, unlike the implications of many conventional models, the felsic volcanic rocks at Tambogrande are interpreted to have only played a passive role in VMS formation."@en . "https://circle.library.ubc.ca/rest/handle/2429/773?expand=metadata"@en . "9993184 bytes"@en . "application/pdf"@en . "\u00C2\u00A0 THE\u00C2\u00A0GENESIS\u00C2\u00A0OF\u00C2\u00A0\u00E2\u0080\u0098GIANT\u00E2\u0080\u0099\u00C2\u00A0COPPER\u00E2\u0080\u0090ZINC\u00E2\u0080\u0090GOLD\u00E2\u0080\u0090SILVER\u00C2\u00A0VOLCANOGENIC\u00C2\u00A0MASSIVE\u00C2\u00A0SULPHIDE\u00C2\u00A0 DEPOSITS\u00C2\u00A0AT\u00C2\u00A0TAMBOGRANDE,\u00C2\u00A0PER\u00C3\u009A:\u00C2\u00A0 AGE,\u00C2\u00A0TECTONIC\u00C2\u00A0SETTING,\u00C2\u00A0PALEOMORPHOLOGY,\u00C2\u00A0LITHOGEOCHEMISTRY\u00C2\u00A0AND\u00C2\u00A0RADIOGENIC\u00C2\u00A0 ISOTOPES\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 by\u00C2\u00A0 \u00C2\u00A0 LAWRENCE\u00C2\u00A0STEPHEN\u00C2\u00A0WINTER\u00C2\u00A0 \u00C2\u00A0 B.Sc.\u00C2\u00A0(Hons.),\u00C2\u00A0Memorial\u00C2\u00A0University\u00C2\u00A0of\u00C2\u00A0Newfoundland,\u00C2\u00A01997\u00C2\u00A0 M.Sc.,\u00C2\u00A0Memorial\u00C2\u00A0University\u00C2\u00A0of\u00C2\u00A0Newfoundland,\u00C2\u00A02000\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 A\u00C2\u00A0THESIS\u00C2\u00A0SUBMITTED\u00C2\u00A0IN\u00C2\u00A0PARTIAL\u00C2\u00A0FULFILLMENT\u00C2\u00A0OF\u00C2\u00A0 THE\u00C2\u00A0REQUIREMENTS\u00C2\u00A0FOR\u00C2\u00A0THE\u00C2\u00A0DEGREE\u00C2\u00A0OF\u00C2\u00A0 \u00C2\u00A0 DOCTOR\u00C2\u00A0OF\u00C2\u00A0PHILOSOPHY\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 in\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 THE\u00C2\u00A0FACULTY\u00C2\u00A0OF\u00C2\u00A0GRADUATE\u00C2\u00A0STUDIES\u00C2\u00A0 \u00C2\u00A0 (Geological\u00C2\u00A0Science)\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 THE\u00C2\u00A0UNIVERSITY\u00C2\u00A0OF\u00C2\u00A0BRITISH\u00C2\u00A0COLUMBIA\u00C2\u00A0 (Vancouver)\u00C2\u00A0 \u00C2\u00A0 APRIL\u00C2\u00A02008\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A9\u00C2\u00A0Lawrence\u00C2\u00A0Stephen\u00C2\u00A0Winter,\u00C2\u00A02008 \u00C2\u00A0 \u00C2\u00A0 Abstract\u00C2\u00A0 \u00C2\u00A0 The\u00C2\u00A0\u00E2\u0080\u0098giant\u00E2\u0080\u0099\u00C2\u00A0Tambogrande\u00C2\u00A0volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0(VMS)\u00C2\u00A0deposits\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0 Cretaceous\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0of\u00C2\u00A0northwestern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0are\u00C2\u00A0some\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0largest\u00C2\u00A0Cu\u00E2\u0080\u0090Zn\u00E2\u0080\u0090Au\u00E2\u0080\u0090Ag\u00E2\u0080\u0090bearing\u00C2\u00A0 massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0known.\u00C2\u00A0\u00C2\u00A0Limited\u00C2\u00A0research\u00C2\u00A0has\u00C2\u00A0been\u00C2\u00A0done\u00C2\u00A0on\u00C2\u00A0these\u00C2\u00A0deposits,\u00C2\u00A0hence\u00C2\u00A0 the\u00C2\u00A0ore\u00C2\u00A0forming\u00C2\u00A0setting\u00C2\u00A0in\u00C2\u00A0which\u00C2\u00A0they\u00C2\u00A0developed\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0key\u00C2\u00A0criteria\u00C2\u00A0that\u00C2\u00A0permitted\u00C2\u00A0such\u00C2\u00A0 anomalous\u00C2\u00A0accumulation\u00C2\u00A0of\u00C2\u00A0base\u00E2\u0080\u0090metal\u00C2\u00A0sulphides\u00C2\u00A0are\u00C2\u00A0not\u00C2\u00A0understood.\u00C2\u00A0\u00C2\u00A0 Based\u00C2\u00A0on\u00C2\u00A0field\u00C2\u00A0relationships\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0host\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0and\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0geochronology,\u00C2\u00A0the\u00C2\u00A0 deposits\u00C2\u00A0formed\u00C2\u00A0during\u00C2\u00A0the\u00C2\u00A0early\u00C2\u00A0stages\u00C2\u00A0of\u00C2\u00A0arc\u00C2\u00A0development\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0latest\u00C2\u00A0Early\u00C2\u00A0Cretaceous\u00C2\u00A0and\u00C2\u00A0 were\u00C2\u00A0related\u00C2\u00A0to\u00C2\u00A0an\u00C2\u00A0extensional\u00C2\u00A0and\u00C2\u00A0arc\u00E2\u0080\u0090rift\u00C2\u00A0phase\u00C2\u00A0(~105\u00E2\u0080\u0090100\u00C2\u00A0Ma,\u00C2\u00A0phase\u00C2\u00A01).\u00C2\u00A0\u00C2\u00A0During\u00C2\u00A0this\u00C2\u00A0time,\u00C2\u00A0 bimodal,\u00C2\u00A0primitive\u00C2\u00A0basalt\u00E2\u0080\u0090dominant\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0were\u00C2\u00A0erupted\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0relatively\u00C2\u00A0deep\u00C2\u00A0marginal\u00C2\u00A0 basin.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0Phase\u00C2\u00A01\u00C2\u00A0rhyolite\u00C2\u00A0is\u00C2\u00A0tholeiitic,\u00C2\u00A0M\u00E2\u0080\u0090type,\u00C2\u00A0and\u00C2\u00A0considered\u00C2\u00A0to\u00C2\u00A0have\u00C2\u00A0formed\u00C2\u00A0from\u00C2\u00A0relatively\u00C2\u00A0 high\u00C2\u00A0temperature,\u00C2\u00A0small\u00C2\u00A0batch\u00C2\u00A0magmas.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0high\u00C2\u00A0heat\u00C2\u00A0flow\u00C2\u00A0and\u00C2\u00A0extensional\u00C2\u00A0setting\u00C2\u00A0extant\u00C2\u00A0 during\u00C2\u00A0the\u00C2\u00A0initial\u00C2\u00A0stages\u00C2\u00A0of\u00C2\u00A0arc\u00C2\u00A0development\u00C2\u00A0were\u00C2\u00A0essential\u00C2\u00A0components\u00C2\u00A0for\u00C2\u00A0forming\u00C2\u00A0a\u00C2\u00A0VMS\u00C2\u00A0 hydrothermal\u00C2\u00A0system.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0subsequent\u00C2\u00A0phase\u00C2\u00A02\u00C2\u00A0(~99\u00E2\u0080\u009091\u00C2\u00A0Ma)\u00C2\u00A0volcanic\u00C2\u00A0sequence\u00C2\u00A0comprises\u00C2\u00A0more\u00C2\u00A0 evolved\u00C2\u00A0mafic\u00C2\u00A0rocks\u00C2\u00A0and\u00C2\u00A0similar,\u00C2\u00A0but\u00C2\u00A0more\u00C2\u00A0depleted,\u00C2\u00A0felsic\u00C2\u00A0rocks\u00C2\u00A0erupted\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0relatively\u00C2\u00A0shallow\u00C2\u00A0 marine\u00C2\u00A0setting.\u00C2\u00A0\u00C2\u00A0Phase\u00C2\u00A02\u00C2\u00A0is\u00C2\u00A0interpreted\u00C2\u00A0to\u00C2\u00A0represent\u00C2\u00A0late\u00E2\u0080\u0090stage\u00C2\u00A0arc\u00C2\u00A0volcanism\u00C2\u00A0during\u00C2\u00A0a\u00C2\u00A0waning\u00C2\u00A0 extensional\u00C2\u00A0regime\u00C2\u00A0and\u00C2\u00A0marked\u00C2\u00A0the\u00C2\u00A0transition\u00C2\u00A0to\u00C2\u00A0contractional\u00C2\u00A0tectonism.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0Tambogrande\u00C2\u00A0deposits\u00C2\u00A0are\u00C2\u00A0particularly\u00C2\u00A0unusual\u00C2\u00A0amongst\u00C2\u00A0the\u00C2\u00A0\u00E2\u0080\u0098giant\u00E2\u0080\u0099\u00C2\u00A0class\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0 deposits\u00C2\u00A0in\u00C2\u00A0that\u00C2\u00A0deposition\u00C2\u00A0largely\u00C2\u00A0occurred\u00C2\u00A0as\u00C2\u00A0seafloor\u00C2\u00A0mound\u00E2\u0080\u0090type\u00C2\u00A0and\u00C2\u00A0not\u00C2\u00A0by\u00C2\u00A0replacement\u00C2\u00A0of\u00C2\u00A0 existing\u00C2\u00A0strata.\u00C2\u00A0\u00C2\u00A0Paleomorphology\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0local\u00C2\u00A0depositional\u00C2\u00A0setting\u00C2\u00A0was\u00C2\u00A0defined\u00C2\u00A0by\u00C2\u00A0seafloor\u00C2\u00A0 depressions\u00C2\u00A0controlled\u00C2\u00A0by\u00C2\u00A0syn\u00E2\u0080\u0090volcanic\u00C2\u00A0faults\u00C2\u00A0and\u00C2\u00A0rhyolitic\u00C2\u00A0volcanism.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0depressions\u00C2\u00A0were\u00C2\u00A0the\u00C2\u00A0 main\u00C2\u00A0controls\u00C2\u00A0on\u00C2\u00A0distribution\u00C2\u00A0and\u00C2\u00A0geometry\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0deposits\u00C2\u00A0and,\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0inherently\u00C2\u00A0confined\u00C2\u00A0 hydrothermal\u00C2\u00A0venting,\u00C2\u00A0enhanced\u00C2\u00A0the\u00C2\u00A0efficiency\u00C2\u00A0of\u00C2\u00A0sulphide\u00C2\u00A0deposition.\u00C2\u00A0 Geochemical\u00C2\u00A0and\u00C2\u00A0radiogenic\u00C2\u00A0isotope\u00C2\u00A0data\u00C2\u00A0indicate\u00C2\u00A0that\u00C2\u00A0the\u00C2\u00A0rhyolites\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0 were\u00C2\u00A0high\u00C2\u00A0temperature\u00C2\u00A0partial\u00C2\u00A0melts\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0juvenile\u00C2\u00A0arc\u00C2\u00A0crust\u00C2\u00A0that\u00C2\u00A0had\u00C2\u00A0inherited\u00C2\u00A0the\u00C2\u00A0isotopic\u00C2\u00A0 signatures\u00C2\u00A0of\u00C2\u00A0continental\u00C2\u00A0crust.\u00C2\u00A0\u00C2\u00A0Moreover,\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0data\u00C2\u00A0suggest\u00C2\u00A0the\u00C2\u00A0metal\u00C2\u00A0budget\u00C2\u00A0was\u00C2\u00A0 sourced\u00C2\u00A0almost\u00C2\u00A0wholly\u00C2\u00A0from\u00C2\u00A0mafic\u00C2\u00A0volcanic\u00C2\u00A0strata.\u00C2\u00A0\u00C2\u00A0Therefore,\u00C2\u00A0unlike\u00C2\u00A0the\u00C2\u00A0implications\u00C2\u00A0of\u00C2\u00A0many\u00C2\u00A0 conventional\u00C2\u00A0models,\u00C2\u00A0the\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0are\u00C2\u00A0interpreted\u00C2\u00A0to\u00C2\u00A0have\u00C2\u00A0only\u00C2\u00A0 played\u00C2\u00A0a\u00C2\u00A0passive\u00C2\u00A0role\u00C2\u00A0in\u00C2\u00A0VMS\u00C2\u00A0formation.\u00C2\u00A0 ii\u00C2\u00A0 \u00C2\u00A0 Table\u00C2\u00A0of\u00C2\u00A0Contents\u00C2\u00A0 Abstract\u00C2\u00A0.........................................................................................................................................................................\u00C2\u00A0ii\u00C2\u00A0 Table\u00C2\u00A0of\u00C2\u00A0Contents\u00C2\u00A0.........................................................................................................................................................\u00C2\u00A0iii\u00C2\u00A0 List\u00C2\u00A0of\u00C2\u00A0Tables\u00C2\u00A0.................................................................................................................................................................\u00C2\u00A0vi\u00C2\u00A0 List\u00C2\u00A0of\u00C2\u00A0Figures\u00C2\u00A0...............................................................................................................................................................\u00C2\u00A0vii\u00C2\u00A0 Acknowledgements\u00C2\u00A0.....................................................................................................................................................\u00C2\u00A0xii\u00C2\u00A0 Dedication\u00C2\u00A0..................................................................................................................................................................\u00C2\u00A0xiii\u00C2\u00A0 Co\u00E2\u0080\u0090Authorship\u00C2\u00A0Statement\u00C2\u00A0...........................................................................................................................................\u00C2\u00A0xiv\u00C2\u00A0 Chapter\u00C2\u00A01.\u00C2\u00A0\u00C2\u00A0Giant\u00C2\u00A0Volcanogenic\u00C2\u00A0Massive\u00C2\u00A0Sulphide\u00C2\u00A0Deposits,\u00C2\u00A0Tambogrande,\u00C2\u00A0NW\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0 1.1\u00C2\u00A0\u00C2\u00A0 Introduction\u00C2\u00A0......................................................................................................................\u00C2\u00A01\u00C2\u00A0 1.2\u00C2\u00A0 Background\u00C2\u00A0and\u00C2\u00A0Approach\u00C2\u00A0................................................................................................\u00C2\u00A02\u00C2\u00A0 1.3\u00C2\u00A0 History\u00C2\u00A0...............................................................................................................................\u00C2\u00A04\u00C2\u00A0 1.4\u00C2\u00A0 VMS\u00C2\u00A0Deposit\u00C2\u00A0Classification\u00C2\u00A0and\u00C2\u00A0Genetic\u00C2\u00A0Models\u00C2\u00A0..............................................................\u00C2\u00A05\u00C2\u00A0 1.5\u00C2\u00A0 Controls\u00C2\u00A0on\u00C2\u00A0\u00E2\u0080\u0098Giant\u00E2\u0080\u0099\u00C2\u00A0VMS\u00C2\u00A0systems\u00C2\u00A0......................................................................................\u00C2\u00A07\u00C2\u00A0 1.6\u00C2\u00A0 Thesis\u00C2\u00A0Objectives...............................................................................................................\u00C2\u00A09\u00C2\u00A0 1.7\u00C2\u00A0 Methodology\u00C2\u00A0...................................................................................................................\u00C2\u00A010\u00C2\u00A0 1.7.1\u00C2\u00A0 Core\u00C2\u00A0Logging\u00C2\u00A0....................................................................................................................................\u00C2\u00A010\u00C2\u00A0 1.7.2\u00C2\u00A0 Regional\u00C2\u00A0Mapping\u00C2\u00A0............................................................................................................................\u00C2\u00A010\u00C2\u00A0 1.7.3\u00C2\u00A0 Geochronology\u00C2\u00A0................................................................................................................................\u00C2\u00A011\u00C2\u00A0 1.7.4\u00C2\u00A0 Lithogeochemistry\u00C2\u00A0...........................................................................................................................\u00C2\u00A011\u00C2\u00A0 1.7.5\u00C2\u00A0 Isotope\u00C2\u00A0Chemistry\u00C2\u00A0............................................................................................................................\u00C2\u00A012\u00C2\u00A0 1.8\u00C2\u00A0 Presentation\u00C2\u00A0....................................................................................................................\u00C2\u00A012\u00C2\u00A0 1.9\u00C2\u00A0 References\u00C2\u00A0......................................................................................................................\u00C2\u00A022\u00C2\u00A0 Chapter\u00C2\u00A02.\u00C2\u00A0\u00C2\u00A0Volcanic\u00C2\u00A0Stratigraphy\u00C2\u00A0and\u00C2\u00A0Geochronology\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Cretaceous\u00C2\u00A0Lancones\u00C2\u00A0Basin,\u00C2\u00A0 Northwestern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0 2.1\u00C2\u00A0 Overview\u00C2\u00A0.........................................................................................................................\u00C2\u00A027\u00C2\u00A0 2.2\u00C2\u00A0 Introduction\u00C2\u00A0....................................................................................................................\u00C2\u00A028\u00C2\u00A0 2.3\u00C2\u00A0 Tectonic\u00C2\u00A0Setting\u00C2\u00A0..............................................................................................................\u00C2\u00A030\u00C2\u00A0 2.4\u00C2\u00A0 Regional\u00C2\u00A0Geology\u00C2\u00A0............................................................................................................\u00C2\u00A031\u00C2\u00A0 2.5\u00C2\u00A0 Volcanic\u00C2\u00A0Stratigraphy\u00C2\u00A0......................................................................................................\u00C2\u00A032\u00C2\u00A0 2.5.1\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0..........................................................................................................\u00C2\u00A035\u00C2\u00A0 2.5.2\u00C2\u00A0 Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation\u00C2\u00A0..................................................................................................................\u00C2\u00A037\u00C2\u00A0 2.5.3\u00C2\u00A0 La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0.......................................................................................................................\u00C2\u00A038\u00C2\u00A0 2.5.4\u00C2\u00A0 Lancones\u00C2\u00A0Formation\u00C2\u00A0........................................................................................................................\u00C2\u00A039\u00C2\u00A0 2.6\u00C2\u00A0 Structural\u00C2\u00A0Geology\u00C2\u00A0..........................................................................................................\u00C2\u00A039\u00C2\u00A0 2.7\u00C2\u00A0 Plutonic\u00C2\u00A0Rocks\u00C2\u00A0.................................................................................................................\u00C2\u00A041\u00C2\u00A0 2.8\u00C2\u00A0 U\u00E2\u0080\u0090Pb\u00C2\u00A0Geochronologic\u00C2\u00A0Data\u00C2\u00A0.............................................................................................\u00C2\u00A042\u00C2\u00A0 2.8.1\u00C2\u00A0 Volcanic\u00C2\u00A0Rocks\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0.......................................................................\u00C2\u00A043\u00C2\u00A0 2.8.2\u00C2\u00A0 Volcanic\u00C2\u00A0Rocks\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Formation\u00C2\u00A0.....................................................................................\u00C2\u00A044\u00C2\u00A0 2.9\u00C2\u00A0 Discussion........................................................................................................................\u00C2\u00A047\u00C2\u00A0 2.9.1\u00C2\u00A0 Depositional\u00C2\u00A0Evolution\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0.................................................................................\u00C2\u00A047\u00C2\u00A0 2.9.2\u00C2\u00A0 Timing\u00C2\u00A0and\u00C2\u00A0Duration\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Volcanic\u00C2\u00A0Arc\u00C2\u00A0.........................................................................................\u00C2\u00A049\u00C2\u00A0 2.9.3\u00C2\u00A0 Age\u00C2\u00A0of\u00C2\u00A0Massive\u00C2\u00A0Sulphide\u00C2\u00A0Deposits\u00C2\u00A0...................................................................................................\u00C2\u00A050\u00C2\u00A0 2.9.4\u00C2\u00A0 Comparison\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0Western\u00C2\u00A0Peruvian\u00C2\u00A0Trough\u00C2\u00A0.............................................\u00C2\u00A051\u00C2\u00A0 iii\u00C2\u00A0 \u00C2\u00A0 2.9.5\u00C2\u00A0 Tectonic\u00C2\u00A0Implications\u00C2\u00A0.......................................................................................................................\u00C2\u00A052\u00C2\u00A0 2.9.6\u00C2\u00A0 Inheritance\u00C2\u00A0in\u00C2\u00A0Zircons\u00C2\u00A0and\u00C2\u00A0Implications\u00C2\u00A0for\u00C2\u00A0Basement\u00C2\u00A0Rocks\u00C2\u00A0..........................................................\u00C2\u00A053\u00C2\u00A0 2.10\u00C2\u00A0 Conclusions\u00C2\u00A0.....................................................................................................................\u00C2\u00A054\u00C2\u00A0 2.11\u00C2\u00A0 References\u00C2\u00A0......................................................................................................................\u00C2\u00A078\u00C2\u00A0 Chapter\u00C2\u00A03.\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0Reconstructed\u00C2\u00A0Cretaceous\u00C2\u00A0Depositional\u00C2\u00A0Setting\u00C2\u00A0for\u00C2\u00A0Giant\u00C2\u00A0VMS\u00C2\u00A0Deposits\u00C2\u00A0at\u00C2\u00A0 Tambogrande,\u00C2\u00A0NW\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0 3.1\u00C2\u00A0 Manuscript\u00C2\u00A0Status\u00C2\u00A0...........................................................................................................\u00C2\u00A083\u00C2\u00A0 3.2\u00C2\u00A0 Abstract\u00C2\u00A0...........................................................................................................................\u00C2\u00A083\u00C2\u00A0 Chapter\u00C2\u00A04.\u00C2\u00A0\u00C2\u00A0Volcanic\u00C2\u00A0Rock\u00C2\u00A0Geochemistry\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0Geodynamic\u00C2\u00A0Setting\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0Deposits\u00C2\u00A0at\u00C2\u00A0 Tambogrande,\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0\u00C2\u00A0 4.1\u00C2\u00A0 Overview\u00C2\u00A0.........................................................................................................................\u00C2\u00A085\u00C2\u00A0 4.2\u00C2\u00A0 Introduction\u00C2\u00A0....................................................................................................................\u00C2\u00A087\u00C2\u00A0 4.3\u00C2\u00A0 Tectonic\u00C2\u00A0Setting\u00C2\u00A0..............................................................................................................\u00C2\u00A089\u00C2\u00A0 4.4\u00C2\u00A0 Regional\u00C2\u00A0Geology\u00C2\u00A0and\u00C2\u00A0Volcanic\u00C2\u00A0Stratigraphy\u00C2\u00A0..................................................................\u00C2\u00A091\u00C2\u00A0 4.4.1\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0..........................................................................................................\u00C2\u00A093\u00C2\u00A0 4.4.2\u00C2\u00A0 Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation\u00C2\u00A0..................................................................................................................\u00C2\u00A094\u00C2\u00A0 4.4.3\u00C2\u00A0 La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0.......................................................................................................................\u00C2\u00A095\u00C2\u00A0 4.4.4\u00C2\u00A0 Lancones\u00C2\u00A0Formation\u00C2\u00A0........................................................................................................................\u00C2\u00A095\u00C2\u00A0 4.5\u00C2\u00A0 Lithogeochemistry\u00C2\u00A0..........................................................................................................\u00C2\u00A095\u00C2\u00A0 4.5.1\u00C2\u00A0 Sampling\u00C2\u00A0Procedures\u00C2\u00A0and\u00C2\u00A0Analytical\u00C2\u00A0Methods\u00C2\u00A0................................................................................\u00C2\u00A095\u00C2\u00A0 4.5.2\u00C2\u00A0 Alteration\u00C2\u00A0and\u00C2\u00A0Element\u00C2\u00A0Mobility\u00C2\u00A0.....................................................................................................\u00C2\u00A096\u00C2\u00A0 4.5.3\u00C2\u00A0 Geochemical\u00C2\u00A0Results\u00C2\u00A0........................................................................................................................\u00C2\u00A097\u00C2\u00A0 4.5.3.1\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0..............................................................................................................\u00C2\u00A097\u00C2\u00A0 4.5.3.2\u00C2\u00A0 Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation\u00C2\u00A0.......................................................................................................................\u00C2\u00A099\u00C2\u00A0 4.5.3.3\u00C2\u00A0 La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0...........................................................................................................................\u00C2\u00A099\u00C2\u00A0 4.5.3.4\u00C2\u00A0 Chemostratigraphy\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0VMS\u00E2\u0080\u0090Host\u00C2\u00A0sequence\u00C2\u00A0.................................................................................\u00C2\u00A0101\u00C2\u00A0 4.6\u00C2\u00A0 Discussion......................................................................................................................\u00C2\u00A0102\u00C2\u00A0 4.6.1\u00C2\u00A0 Petrochemical\u00C2\u00A0Variations\u00C2\u00A0in\u00C2\u00A0Mafic\u00C2\u00A0Volcanic\u00C2\u00A0Rocks\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0....................................\u00C2\u00A0102\u00C2\u00A0 4.6.2\u00C2\u00A0 Felsic\u00C2\u00A0Volcanic\u00C2\u00A0Rock\u00C2\u00A0Petrochemistry\u00C2\u00A0and\u00C2\u00A0Association\u00C2\u00A0with\u00C2\u00A0VMS\u00C2\u00A0...................................................\u00C2\u00A0104\u00C2\u00A0 4.6.3\u00C2\u00A0 Implications\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0Tectonic\u00C2\u00A0Setting\u00C2\u00A0.............................................................................................\u00C2\u00A0108\u00C2\u00A0 4.7\u00C2\u00A0 Summary\u00C2\u00A0.......................................................................................................................\u00C2\u00A0110\u00C2\u00A0 4.8\u00C2\u00A0 References\u00C2\u00A0....................................................................................................................\u00C2\u00A0135\u00C2\u00A0 Chapter\u00C2\u00A05.\u00C2\u00A0\u00C2\u00A0Pb\u00E2\u0080\u0090Sr\u00E2\u0080\u0090Nd\u00C2\u00A0Isotope\u00C2\u00A0Systematics\u00C2\u00A0of\u00C2\u00A0Cretaceous\u00C2\u00A0Arc\u00C2\u00A0Volcanic\u00C2\u00A0Rocks\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0 Basin\u00C2\u00A0near\u00C2\u00A0Tambogrande,\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A0Implications\u00C2\u00A0for\u00C2\u00A0VMS\u00C2\u00A0Deposit\u00C2\u00A0Formation\u00C2\u00A0 5.1\u00C2\u00A0 Overview\u00C2\u00A0.......................................................................................................................\u00C2\u00A0142\u00C2\u00A0 5.2\u00C2\u00A0 Introduction\u00C2\u00A0..................................................................................................................\u00C2\u00A0144\u00C2\u00A0 5.3\u00C2\u00A0 Regional\u00C2\u00A0Geology\u00C2\u00A0and\u00C2\u00A0Tectonic\u00C2\u00A0Setting\u00C2\u00A0........................................................................\u00C2\u00A0145\u00C2\u00A0 5.4\u00C2\u00A0 Volcanic\u00C2\u00A0Stratigraphy\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0................................................................\u00C2\u00A0148\u00C2\u00A0 5.5\u00C2\u00A0 Andean\u00C2\u00A0Isotopic\u00C2\u00A0Framework\u00C2\u00A0.........................................................................................\u00C2\u00A0150\u00C2\u00A0 5.6\u00C2\u00A0 Pb,\u00C2\u00A0Sm\u00E2\u0080\u0090Nd\u00C2\u00A0and\u00C2\u00A0Rb\u00E2\u0080\u0090Sr\u00C2\u00A0Isotope\u00C2\u00A0Geochemistry\u00C2\u00A0................................................................\u00C2\u00A0152\u00C2\u00A0 5.7\u00C2\u00A0 Analytical\u00C2\u00A0Methods\u00C2\u00A0.......................................................................................................\u00C2\u00A0153\u00C2\u00A0 5.7.1\u00C2\u00A0 Pb\u00C2\u00A0Isotope\u00C2\u00A0Analysis,\u00C2\u00A0Mineral\u00C2\u00A0Separates\u00C2\u00A0.........................................................................................\u00C2\u00A0153\u00C2\u00A0 5.7.2\u00C2\u00A0 Pb,\u00C2\u00A0Rb\u00E2\u0080\u0090Sr,\u00C2\u00A0Sm\u00E2\u0080\u0090Nd\u00C2\u00A0Isotope\u00C2\u00A0Analysis,\u00C2\u00A0Whole\u00C2\u00A0Rock\u00C2\u00A0Samples\u00C2\u00A0.............................................................\u00C2\u00A0154\u00C2\u00A0 5.8\u00C2\u00A0 Results\u00C2\u00A0...........................................................................................................................\u00C2\u00A0155\u00C2\u00A0 5.8.1\u00C2\u00A0 Volcanic\u00C2\u00A0Rocks\u00C2\u00A0...............................................................................................................................\u00C2\u00A0155\u00C2\u00A0 5.8.2\u00C2\u00A0 Massive\u00C2\u00A0Sulphide\u00C2\u00A0Deposits\u00C2\u00A0............................................................................................................\u00C2\u00A0158\u00C2\u00A0 5.9\u00C2\u00A0 Discussion......................................................................................................................\u00C2\u00A0159\u00C2\u00A0 iv\u00C2\u00A0 \u00C2\u00A0 5.9.1\u00C2\u00A0 Volcanic\u00C2\u00A0Rock\u00C2\u00A0Petrogenesis\u00C2\u00A0...........................................................................................................\u00C2\u00A0159\u00C2\u00A0 5.9.2\u00C2\u00A0 Possible\u00C2\u00A0Linkages\u00C2\u00A0Between\u00C2\u00A0Petrogenesis\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Felsic\u00C2\u00A0Volcanic\u00C2\u00A0Suite\u00C2\u00A0and\u00C2\u00A0VMS\u00C2\u00A0Formation\u00C2\u00A0..........\u00C2\u00A0163\u00C2\u00A0 5.10\u00C2\u00A0 Summary\u00C2\u00A0and\u00C2\u00A0Conclusions\u00C2\u00A0............................................................................................\u00C2\u00A0166\u00C2\u00A0 5.11\u00C2\u00A0 References\u00C2\u00A0....................................................................................................................\u00C2\u00A0187\u00C2\u00A0 Chapter\u00C2\u00A06.\u00C2\u00A0\u00C2\u00A0Summary,\u00C2\u00A0Discussion\u00C2\u00A0and\u00C2\u00A0Unresolved\u00C2\u00A0Questions\u00C2\u00A0 6.1\u00C2\u00A0 Summary\u00C2\u00A0and\u00C2\u00A0Main\u00C2\u00A0Conclusions\u00C2\u00A0...................................................................................\u00C2\u00A0192\u00C2\u00A0 6.2\u00C2\u00A0 Discussion\u00C2\u00A0and\u00C2\u00A0Ideas\u00C2\u00A0.....................................................................................................\u00C2\u00A0198\u00C2\u00A0 6.2.1\u00C2\u00A0 Timing\u00C2\u00A0and\u00C2\u00A0Tectonic\u00C2\u00A0Setting\u00C2\u00A0..........................................................................................................\u00C2\u00A0198\u00C2\u00A0 6.2.2\u00C2\u00A0 Where\u00E2\u0080\u0099s\u00C2\u00A0the\u00C2\u00A0Intrusion?\u00C2\u00A0..................................................................................................................\u00C2\u00A0199\u00C2\u00A0 6.3\u00C2\u00A0 Outstanding\u00C2\u00A0Issues\u00C2\u00A0and\u00C2\u00A0Directions\u00C2\u00A0for\u00C2\u00A0Future\u00C2\u00A0Research\u00C2\u00A0..............................................\u00C2\u00A0200\u00C2\u00A0 6.3.1\u00C2\u00A0 At\u00C2\u00A0Tambogrande\u00C2\u00A0and\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0.................................................................................\u00C2\u00A0200\u00C2\u00A0 6.3.2\u00C2\u00A0 In\u00C2\u00A0the\u00C2\u00A0Western\u00C2\u00A0Peruvian\u00C2\u00A0Trough\u00C2\u00A0...................................................................................................\u00C2\u00A0201\u00C2\u00A0 6.3.3\u00C2\u00A0 Globally\u00C2\u00A0..........................................................................................................................................\u00C2\u00A0203\u00C2\u00A0 6.4\u00C2\u00A0 References\u00C2\u00A0....................................................................................................................\u00C2\u00A0205\u00C2\u00A0 Appendix\u00C2\u00A0A.\u00C2\u00A0\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0Zircon\u00C2\u00A0Sample\u00C2\u00A0Preparation,\u00C2\u00A0Analysis\u00C2\u00A0and\u00C2\u00A0Additional\u00C2\u00A0Data\u00C2\u00A0 A.1\u00C2\u00A0 Methodology\u00C2\u00A0.................................................................................................................\u00C2\u00A0210\u00C2\u00A0 A.2\u00C2\u00A0 Additional\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0Zircon\u00C2\u00A0Geochronologic\u00C2\u00A0Data\u00C2\u00A0...............................................................\u00C2\u00A0217\u00C2\u00A0 A.3\u00C2\u00A0 Results\u00C2\u00A0...........................................................................................................................\u00C2\u00A0217\u00C2\u00A0 A.4\u00C2\u00A0 References\u00C2\u00A0....................................................................................................................\u00C2\u00A0225\u00C2\u00A0 Appendix\u00C2\u00A0B.\u00C2\u00A0\u00C2\u00A0Ar\u00E2\u0080\u0090Ar\u00C2\u00A0Geochronologic\u00C2\u00A0Data\u00C2\u00A0 B.1\u00C2\u00A0 Methodology\u00C2\u00A0.................................................................................................................\u00C2\u00A0226\u00C2\u00A0 B.2\u00C2\u00A0 Results\u00C2\u00A0...........................................................................................................................\u00C2\u00A0227\u00C2\u00A0 B.3\u00C2\u00A0 References\u00C2\u00A0....................................................................................................................\u00C2\u00A0236\u00C2\u00A0 Appendix\u00C2\u00A0C.\u00C2\u00A0\u00C2\u00A0Lithogeochemistry\u00C2\u00A0 C.1\u00C2\u00A0 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Figure\u00C2\u00A02.3\u00C2\u00A0(on\u00C2\u00A0the\u00C2\u00A0following\u00C2\u00A0page).\u00C2\u00A0\u00C2\u00A0Schematic\u00C2\u00A0paleogeographic\u00C2\u00A0model\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0development\u00C2\u00A0of\u00C2\u00A0Per\u00C3\u00BA\u00E2\u0080\u0090Ecuador\u00C2\u00A0 segment\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0western\u00C2\u00A0margin\u00C2\u00A0of\u00C2\u00A0South\u00C2\u00A0America\u00C2\u00A0(SA)\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0Jurassic\u00C2\u00A0to\u00C2\u00A0present\u00C2\u00A0using\u00C2\u00A0data\u00C2\u00A0from\u00C2\u00A0Mourier\u00C2\u00A0 et\u00C2\u00A0al.\u00C2\u00A0(1988),\u00C2\u00A0Mitouard\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1990),\u00C2\u00A0Litherland\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1994),\u00C2\u00A0Aspden\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1995),\u00C2\u00A0\u00C2\u00A0Noble\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1997),\u00C2\u00A0Arculus\u00C2\u00A0 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volcaniclastic\u00C2\u00A0rock.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0sample\u00C2\u00A0contains\u00C2\u00A0an\u00C2\u00A0equal\u00C2\u00A0proportion\u00C2\u00A0of\u00C2\u00A0aphyric\u00C2\u00A0to\u00C2\u00A0weakly\u00C2\u00A0feldspar\u00C2\u00A0porphyritic\u00C2\u00A0(W)\u00C2\u00A0 clasts\u00C2\u00A0and\u00C2\u00A0coarse\u00C2\u00A0feldspar\u00C2\u00A0(C)\u00C2\u00A0porphyry\u00C2\u00A0clasts.\u00C2\u00A0\u00C2\u00A0Amygdaloidal\u00C2\u00A0clasts\u00C2\u00A0(A)\u00C2\u00A0are\u00C2\u00A0present\u00C2\u00A0but\u00C2\u00A0are\u00C2\u00A0generally\u00C2\u00A0not\u00C2\u00A0 common.\u00C2\u00A0\u00C2\u00A0Clast\u00C2\u00A0margins\u00C2\u00A0often\u00C2\u00A0are\u00C2\u00A0not\u00C2\u00A0easily\u00C2\u00A0discernible.\u00C2\u00A0\u00C2\u00A0D.\u00C2\u00A0Thin\u00E2\u0080\u0090\u00C2\u00A0to\u00C2\u00A0thick\u00E2\u0080\u0090bedded\u00C2\u00A0feldspar\u00C2\u00A0crystal\u00C2\u00A0to\u00C2\u00A0ash\u00E2\u0080\u0090 sized\u00C2\u00A0tuff;\u00C2\u00A0reworked\u00C2\u00A0facies\u00C2\u00A0at\u00C2\u00A0top\u00C2\u00A0of\u00C2\u00A0formation.\u00C2\u00A0................................................................................................\u00C2\u00A068\u00C2\u00A0 Figure\u00C2\u00A02.10.\u00C2\u00A0\u00C2\u00A0Field\u00C2\u00A0photographs\u00C2\u00A0of\u00C2\u00A0mafic\u00C2\u00A0rocks\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation:\u00C2\u00A0\u00C2\u00A0A.\u00C2\u00A0Moderately\u00C2\u00A0west\u00E2\u0080\u0090dipping,\u00C2\u00A0thick\u00C2\u00A0 massive\u00C2\u00A0basaltic\u00E2\u0080\u0090andesite\u00C2\u00A0flows.\u00C2\u00A0\u00C2\u00A0Felsic\u00C2\u00A0stocks\u00C2\u00A0and\u00C2\u00A0dykes\u00C2\u00A0cut\u00C2\u00A0perpendicular\u00C2\u00A0to\u00C2\u00A0bedding.\u00C2\u00A0\u00C2\u00A0B.\u00C2\u00A0\u00C2\u00A0Basaltic\u00C2\u00A0andesite\u00C2\u00A0 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Figure\u00C2\u00A02.10\u00C2\u00A0(continued).\u00C2\u00A0\u00C2\u00A0G.\u00C2\u00A0Rhyolitic\u00C2\u00A0quartz\u00C2\u00A0crystal\u00E2\u0080\u0090rich\u00C2\u00A0and\u00C2\u00A0lithic\u00C2\u00A0tuff.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0H.\u00C2\u00A0Coarse,\u00C2\u00A0boulder\u00C2\u00A0breccia\u00C2\u00A0with\u00C2\u00A0chaotic,\u00C2\u00A0 unsorted,\u00C2\u00A0subround\u00C2\u00A0(pillow?)\u00C2\u00A0clasts.\u00C2\u00A0\u00C2\u00A0Talus\u00C2\u00A0breccia.\u00C2\u00A0\u00C2\u00A0I.\u00C2\u00A0Medium\u00C2\u00A0bedded,\u00C2\u00A0well\u00C2\u00A0sorted\u00C2\u00A0and\u00C2\u00A0locally\u00C2\u00A0cross\u00C2\u00A0bedded\u00C2\u00A0 (arrow),\u00C2\u00A0pebble\u00E2\u0080\u0090\u00C2\u00A0to\u00C2\u00A0sand\u00E2\u0080\u0090sized,\u00C2\u00A0mafic\u00E2\u0080\u0090dominated\u00C2\u00A0volcaniclastic\u00C2\u00A0rocks.\u00C2\u00A0.............................................................\u00C2\u00A070\u00C2\u00A0 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2.6.\u00C2\u00A0\u00C2\u00A0Inset\u00C2\u00A0section\u00C2\u00A0shows\u00C2\u00A0the\u00C2\u00A0Tambogrande\u00C2\u00A0VMS\u00C2\u00A0section\u00C2\u00A0in\u00C2\u00A0more\u00C2\u00A0detail.\u00C2\u00A0\u00C2\u00A0Age\u00C2\u00A0data\u00C2\u00A0from\u00C2\u00A0this\u00C2\u00A0study\u00C2\u00A0are\u00C2\u00A0shown\u00C2\u00A0 in\u00C2\u00A0their\u00C2\u00A0relative\u00C2\u00A0stratigraphic\u00C2\u00A0positions.\u00C2\u00A0\u00C2\u00A0Ages\u00C2\u00A0of\u00C2\u00A0plutonic\u00C2\u00A0rocks\u00C2\u00A0provided\u00C2\u00A0herein\u00C2\u00A0(Appendices\u00C2\u00A0A,\u00C2\u00A0B).\u00C2\u00A0...............\u00C2\u00A072\u00C2\u00A0 Figure\u00C2\u00A02.13.\u00C2\u00A0(following\u00C2\u00A0page)\u00C2\u00A0\u00C2\u00A0238U/206Pb\u00C2\u00A0versus\u00C2\u00A0207Pb/206Pb\u00C2\u00A0Tera\u00E2\u0080\u0090Wasserburg\u00C2\u00A0plots\u00C2\u00A0(Tera\u00C2\u00A0and\u00C2\u00A0Wasserburg,\u00C2\u00A01972)\u00C2\u00A0for\u00C2\u00A0 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diagrams\u00C2\u00A0are\u00C2\u00A0rare\u00C2\u00A0earth\u00C2\u00A0elements\u00C2\u00A0only\u00C2\u00A0and\u00C2\u00A0are\u00C2\u00A0normalized\u00C2\u00A0to\u00C2\u00A0chondrite\u00C2\u00A0values.\u00C2\u00A0\u00C2\u00A0Element\u00C2\u00A0order\u00C2\u00A0and\u00C2\u00A0 normalizing\u00C2\u00A0values\u00C2\u00A0follow\u00C2\u00A0Sun\u00C2\u00A0and\u00C2\u00A0McDonough\u00C2\u00A0(1989).\u00C2\u00A0.................................................................................\u00C2\u00A0123\u00C2\u00A0 Figure\u00C2\u00A04.13\u00C2\u00A0(following\u00C2\u00A0page).\u00C2\u00A0\u00C2\u00A0Multi\u00E2\u0080\u0090element\u00C2\u00A0bivariate\u00C2\u00A0plots\u00C2\u00A0for\u00C2\u00A0basalt,\u00C2\u00A0dacite,\u00C2\u00A0and\u00C2\u00A0rhyolite\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0vicinity\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0 deposits\u00C2\u00A0at\u00C2\u00A0Tambogrande.\u00C2\u00A0\u00C2\u00A0A.\u00C2\u00A0Zr/TiO2\u00C2\u00A0vs.\u00C2\u00A0Nb/Y\u00C2\u00A0(Winchester\u00C2\u00A0and\u00C2\u00A0Floyd,\u00C2\u00A01977).\u00C2\u00A0\u00C2\u00A0B.\u00C2\u00A0Na2O+K2O\u00C2\u00A0vs.\u00C2\u00A0SiO2\u00C2\u00A0(Le\u00C2\u00A0Bas\u00C2\u00A0et\u00C2\u00A0 al.,\u00C2\u00A01986).\u00C2\u00A0\u00C2\u00A0C.\u00C2\u00A0Fe2O3+MgO\u00C2\u00A0vs.\u00C2\u00A0SiO2.\u00C2\u00A0\u00C2\u00A0D.\u00C2\u00A0TiO2\u00C2\u00A0vs.\u00C2\u00A0Zr.\u00C2\u00A0\u00C2\u00A0E.\u00C2\u00A0\u00C2\u00A0P2O5\u00C2\u00A0vs.\u00C2\u00A0Zr.\u00C2\u00A0\u00C2\u00A0F.\u00C2\u00A0V\u00C2\u00A0vs.\u00C2\u00A0Zr/TiO2.\u00C2\u00A0\u00C2\u00A0G.\u00C2\u00A0Hf\u00C2\u00A0vs.\u00C2\u00A0Nb.\u00C2\u00A0\u00C2\u00A0H.\u00C2\u00A0Zr/Y\u00C2\u00A0vs.\u00C2\u00A0Y.\u00C2\u00A0\u00C2\u00A0I.\u00C2\u00A0 La/Yb\u00C2\u00A0vs\u00C2\u00A0Yb\u00C2\u00A0(chondrite\u00E2\u0080\u0090normalized\u00C2\u00A0values\u00C2\u00A0using\u00C2\u00A0Sun\u00C2\u00A0and\u00C2\u00A0McDonough\u00C2\u00A0(1989)).\u00C2\u00A0\u00C2\u00A0J.\u00C2\u00A0\u00C2\u00A0Th\u00C2\u00A0vs.\u00C2\u00A0Zr.\u00C2\u00A0.........................\u00C2\u00A0123\u00C2\u00A0 Figure\u00C2\u00A04.14.\u00C2\u00A0\u00C2\u00A0Ta/Yb\u00C2\u00A0versus\u00C2\u00A0Th/Yb\u00C2\u00A0plot\u00C2\u00A0after\u00C2\u00A0Pearce\u00C2\u00A0(1983).\u00C2\u00A0\u00C2\u00A0Only\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0and\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0 Formation\u00C2\u00A0basalt\u00C2\u00A0shown\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0data\u00C2\u00A0limits\u00C2\u00A0for\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0D\u00C2\u00A0=\u00C2\u00A0depleted\u00C2\u00A0mantle.\u00C2\u00A0\u00C2\u00A0E\u00C2\u00A0=\u00C2\u00A0enriched\u00C2\u00A0 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from\u00C2\u00A0Piercey\u00C2\u00A0(2001).\u00C2\u00A0........................................................................................................................................\u00C2\u00A0258\u00C2\u00A0 xii\u00C2\u00A0 \u00C2\u00A0 Acknowledgements\u00C2\u00A0 This\u00C2\u00A0project\u00C2\u00A0began\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A0Roundup\u00C2\u00A0conference\u00C2\u00A0in\u00C2\u00A0Vancouver\u00C2\u00A0in\u00C2\u00A0January,\u00C2\u00A01999,\u00C2\u00A0when\u00C2\u00A0Steve\u00C2\u00A0Piercey\u00C2\u00A0 introduced\u00C2\u00A0me\u00C2\u00A0to\u00C2\u00A0Jim\u00C2\u00A0Mortensen.\u00C2\u00A0\u00C2\u00A0I\u00C2\u00A0thank\u00C2\u00A0both\u00C2\u00A0of\u00C2\u00A0them\u00C2\u00A0for\u00C2\u00A0getting\u00C2\u00A0me\u00C2\u00A0started\u00C2\u00A0on\u00C2\u00A0this\u00C2\u00A0journey.\u00C2\u00A0\u00C2\u00A0Dick\u00C2\u00A0Tosdal\u00C2\u00A0 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enabled\u00C2\u00A0the\u00C2\u00A0formation\u00C2\u00A0of\u00C2\u00A0giant\u00C2\u00A0deposits,\u00C2\u00A0and\u00C2\u00A0even\u00C2\u00A0fewer\u00C2\u00A0constraints\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0geological\u00C2\u00A0 processes\u00C2\u00A0which\u00C2\u00A0permit\u00C2\u00A0the\u00C2\u00A0generation\u00C2\u00A0of\u00C2\u00A0multiple\u00C2\u00A0giant\u00C2\u00A0deposits.\u00C2\u00A0\u00C2\u00A0As\u00C2\u00A0many\u00C2\u00A0of\u00C2\u00A0these\u00C2\u00A0deposits\u00C2\u00A0 have\u00C2\u00A0not\u00C2\u00A0been\u00C2\u00A0developed\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0mining\u00C2\u00A0stage,\u00C2\u00A0little\u00C2\u00A0research\u00C2\u00A0has\u00C2\u00A0been\u00C2\u00A0done\u00C2\u00A0to\u00C2\u00A0elucidate\u00C2\u00A0 understanding\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0potential\u00C2\u00A0world\u00E2\u0080\u0090class\u00C2\u00A0district\u00C2\u00A0at\u00C2\u00A0Tambogrande.\u00C2\u00A0\u00C2\u00A0Therefore,\u00C2\u00A0the\u00C2\u00A0theme\u00C2\u00A0of\u00C2\u00A0 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geology\u00C2\u00A0of\u00C2\u00A0well\u00E2\u0080\u0090preserved\u00C2\u00A0examples\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0will\u00C2\u00A0assist\u00C2\u00A0in\u00C2\u00A0refining\u00C2\u00A0VMS\u00C2\u00A0deposit\u00C2\u00A0models\u00C2\u00A0 and\u00C2\u00A0aid\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0understanding\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0genesis\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0largest\u00C2\u00A0hydrothermal\u00C2\u00A0ore\u00C2\u00A0deposits.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 1.2\u00C2\u00A0 Background\u00C2\u00A0and\u00C2\u00A0Approach\u00C2\u00A0 Continental\u00C2\u00A0margin\u00C2\u00A0arc\u00C2\u00A0sequences\u00C2\u00A0are\u00C2\u00A0known\u00C2\u00A0from\u00C2\u00A0Ecuador\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0north\u00C2\u00A0to\u00C2\u00A0Tierra\u00C2\u00A0del\u00C2\u00A0 Fuego\u00C2\u00A0in\u00C2\u00A0southernmost\u00C2\u00A0Chile\u00C2\u00A0and\u00C2\u00A0Argentina\u00C2\u00A0(Dalziel,\u00C2\u00A01981;\u00C2\u00A0Atherton\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01983;\u00C2\u00A0Vergara\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A0 1995;\u00C2\u00A0Jaillard\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01996;\u00C2\u00A0Hanson\u00C2\u00A0and\u00C2\u00A0Wilson,\u00C2\u00A01991)\u00C2\u00A0and\u00C2\u00A0represent\u00C2\u00A0vestiges\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0Mesozoic\u00C2\u00A0arc\u00E2\u0080\u0090 related\u00C2\u00A0rift\u00C2\u00A0system\u00C2\u00A0(i.e.,\u00C2\u00A0intra\u00E2\u0080\u0090arc\u00C2\u00A0or\u00C2\u00A0back\u00E2\u0080\u0090arc)\u00C2\u00A0that\u00C2\u00A0developed\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A0leading\u00C2\u00A0edge\u00C2\u00A0of\u00C2\u00A0western\u00C2\u00A0 continental\u00C2\u00A0South\u00C2\u00A0America.\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0variety\u00C2\u00A0of\u00C2\u00A0ore\u00C2\u00A0deposit\u00C2\u00A0types\u00C2\u00A0occur\u00C2\u00A0throughout\u00C2\u00A0the\u00C2\u00A0rift\u00C2\u00A0sequences,\u00C2\u00A0 including\u00C2\u00A0Chilean\u00C2\u00A0manto,\u00C2\u00A0skarn,\u00C2\u00A0Fe\u00E2\u0080\u0090oxide\u00C2\u00A0Cu\u00E2\u0080\u0090Au,\u00C2\u00A0porphyry\u00C2\u00A0Cu\u00E2\u0080\u0090Au,\u00C2\u00A0and\u00C2\u00A0VMS\u00C2\u00A0deposits,\u00C2\u00A0though\u00C2\u00A0few\u00C2\u00A0 VMS\u00C2\u00A0deposits\u00C2\u00A0other\u00C2\u00A0than\u00C2\u00A0those\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0are\u00C2\u00A0economically\u00C2\u00A0significant.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0tectonic\u00C2\u00A0and\u00C2\u00A0 magmatic\u00C2\u00A0processes\u00C2\u00A0that\u00C2\u00A0formed\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin,\u00C2\u00A0the\u00C2\u00A0northernmost\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Mesozoic\u00C2\u00A0arc\u00E2\u0080\u0090rift\u00C2\u00A0 sequences,\u00C2\u00A0underpin\u00C2\u00A0the\u00C2\u00A0processes\u00C2\u00A0that\u00C2\u00A0enabled\u00C2\u00A0the\u00C2\u00A0formation\u00C2\u00A0of\u00C2\u00A0these\u00C2\u00A0unusually\u00C2\u00A0large\u00C2\u00A0 deposits.\u00C2\u00A0\u00C2\u00A0Understanding\u00C2\u00A0the\u00C2\u00A0igneous\u00E2\u0080\u0090volcanic\u00C2\u00A0and\u00C2\u00A0tectonic\u00C2\u00A0evolution\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0 Chapter\u00C2\u00A01\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A02\u00C2\u00A0 thus\u00C2\u00A0provides\u00C2\u00A0a\u00C2\u00A0basis\u00C2\u00A0for\u00C2\u00A0understanding\u00C2\u00A0the\u00C2\u00A0unique\u00C2\u00A0genetic\u00C2\u00A0attributes\u00C2\u00A0that\u00C2\u00A0enabled\u00C2\u00A0the\u00C2\u00A0 formation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Tambogrande\u00C2\u00A0deposits.\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0study\u00C2\u00A0area\u00C2\u00A0in\u00C2\u00A0northwestern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0is\u00C2\u00A0situated\u00C2\u00A0within\u00C2\u00A0an\u00C2\u00A0enigmatic\u00C2\u00A0position\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0 Andes\u00C2\u00A0orogen\u00C2\u00A0known\u00C2\u00A0as\u00C2\u00A0the\u00C2\u00A0Huancabamba\u00C2\u00A0deflection\u00C2\u00A0(Mourier\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01988;\u00C2\u00A0Mitouard\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A0 1990).\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0major\u00C2\u00A0oroclinal\u00C2\u00A0bend\u00C2\u00A0marks\u00C2\u00A0an\u00C2\u00A0abrupt\u00C2\u00A0transition\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0north\u00E2\u0080\u0090northwest\u00C2\u00A0trending\u00C2\u00A0 Peruvian\u00C2\u00A0Andes\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0north\u00E2\u0080\u0090northeast\u00C2\u00A0trending\u00C2\u00A0Ecuadorian\u00C2\u00A0Andes.\u00C2\u00A0\u00C2\u00A0Though\u00C2\u00A0the\u00C2\u00A0tectonic\u00C2\u00A0history\u00C2\u00A0 of\u00C2\u00A0the\u00C2\u00A0orocline\u00C2\u00A0is\u00C2\u00A0not\u00C2\u00A0well\u00C2\u00A0understood.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0Ecuadorian\u00C2\u00A0and\u00C2\u00A0Peruvian\u00C2\u00A0segments\u00C2\u00A0also\u00C2\u00A0record\u00C2\u00A0 somewhat\u00C2\u00A0different\u00C2\u00A0accretionary\u00C2\u00A0and\u00C2\u00A0magmatic\u00C2\u00A0histories\u00C2\u00A0(Jaillard\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01999,\u00C2\u00A02000;\u00C2\u00A0Benavides\u00E2\u0080\u0090 C\u00C3\u00A1ceres,\u00C2\u00A01999)\u00C2\u00A0adding\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0significance\u00C2\u00A0of\u00C2\u00A0this\u00C2\u00A0transitional\u00C2\u00A0zone.\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0better\u00C2\u00A0understanding\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0development\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0is\u00C2\u00A0integral\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0development\u00C2\u00A0of\u00C2\u00A0tectonic\u00C2\u00A0models\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 Huancabamba\u00C2\u00A0deflection\u00C2\u00A0and\u00C2\u00A0Mesozoic\u00C2\u00A0Andean\u00C2\u00A0orogenesis.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 To\u00C2\u00A0summarize,\u00C2\u00A0this\u00C2\u00A0thesis\u00C2\u00A0adds\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0theoretical\u00C2\u00A0and\u00C2\u00A0applied\u00C2\u00A0knowledge\u00C2\u00A0base\u00C2\u00A0on\u00C2\u00A0giant\u00C2\u00A0 VMS\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0genesis\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0by\u00C2\u00A0documenting\u00C2\u00A0the\u00C2\u00A0regional\u00C2\u00A0 tectonomagmatic\u00C2\u00A0setting\u00C2\u00A0and\u00C2\u00A0also\u00C2\u00A0the\u00C2\u00A0detailed\u00C2\u00A0local\u00C2\u00A0volcanological,\u00C2\u00A0structural\u00C2\u00A0and\u00C2\u00A0stratigraphic\u00C2\u00A0 controls\u00C2\u00A0on\u00C2\u00A0VMS\u00C2\u00A0formation\u00C2\u00A0at\u00C2\u00A0Tambogrande.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0pristine\u00C2\u00A0state\u00C2\u00A0of\u00C2\u00A0preservation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0deposits,\u00C2\u00A0 well\u00C2\u00A0constrained\u00C2\u00A0volcanic\u00C2\u00A0stratigraphic\u00C2\u00A0sections,\u00C2\u00A0and\u00C2\u00A0good\u00C2\u00A0understanding\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0tectonic\u00C2\u00A0history\u00C2\u00A0 of\u00C2\u00A0the\u00C2\u00A0region\u00C2\u00A0provide\u00C2\u00A0excellent\u00C2\u00A0controls\u00C2\u00A0to\u00C2\u00A0establish\u00C2\u00A0the\u00C2\u00A0geologic\u00C2\u00A0framework.\u00C2\u00A0\u00C2\u00A0Furthermore,\u00C2\u00A0this\u00C2\u00A0 study\u00C2\u00A0contributes\u00C2\u00A0to\u00C2\u00A0improved\u00C2\u00A0genetic\u00C2\u00A0models\u00C2\u00A0for\u00C2\u00A0such\u00C2\u00A0giant\u00C2\u00A0ore\u00C2\u00A0deposits\u00C2\u00A0as\u00C2\u00A0well\u00C2\u00A0as\u00C2\u00A0more\u00C2\u00A0 efficient\u00C2\u00A0exploration\u00C2\u00A0methodologies.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0addition,\u00C2\u00A0better\u00C2\u00A0documentation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Tambogrande\u00C2\u00A0 deposits\u00C2\u00A0and\u00C2\u00A0tectonomagmatic\u00C2\u00A0history\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0fills\u00C2\u00A0a\u00C2\u00A0significant\u00C2\u00A0void\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0 geological\u00C2\u00A0knowledgebase\u00C2\u00A0of\u00C2\u00A0one\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0world\u00E2\u0080\u0099s\u00C2\u00A0major\u00C2\u00A0metallogenic\u00C2\u00A0belts,\u00C2\u00A0as\u00C2\u00A0well\u00C2\u00A0as\u00C2\u00A0one\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 more\u00C2\u00A0poorly\u00C2\u00A0understood\u00C2\u00A0parts\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Andes.\u00C2\u00A0 Chapter\u00C2\u00A01\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A03\u00C2\u00A0 1.3\u00C2\u00A0 History\u00C2\u00A0 \u00C2\u00A0 Iron\u00C2\u00A0oxide\u00C2\u00A0occurrences\u00C2\u00A0were\u00C2\u00A0documented\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0nearly\u00C2\u00A0100\u00C2\u00A0years\u00C2\u00A0ago\u00C2\u00A0(Boletin\u00C2\u00A0 de\u00C2\u00A0la\u00C2\u00A0Sociedad\u00C2\u00A0Geologica\u00C2\u00A0del\u00C2\u00A0Per\u00C3\u00BA,\u00C2\u00A01904,\u00C2\u00A0in\u00C2\u00A0Tegart\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02000).\u00C2\u00A0\u00C2\u00A0But\u00C2\u00A0it\u00C2\u00A0was\u00C2\u00A0not\u00C2\u00A0until\u00C2\u00A0the\u00C2\u00A0mid\u00E2\u0080\u0090 1970\u00E2\u0080\u0099s\u00C2\u00A0that\u00C2\u00A0interest\u00C2\u00A0was\u00C2\u00A0spurred\u00C2\u00A0again\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0area\u00C2\u00A0by\u00C2\u00A0the\u00C2\u00A0joint\u00C2\u00A0venture\u00C2\u00A0of\u00C2\u00A0French\u00C2\u00A0state\u00E2\u0080\u0090owned\u00C2\u00A0 Bureau\u00C2\u00A0de\u00C2\u00A0Recherches,\u00C2\u00A0Geologiques\u00C2\u00A0et\u00C2\u00A0Minieres\u00C2\u00A0(BRGM)\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0Instituto\u00C2\u00A0Geologico\u00C2\u00A0Minero\u00C2\u00A0y\u00C2\u00A0 Metalurgico\u00C2\u00A0(INGEMMET)\u00C2\u00A0which\u00C2\u00A0found\u00C2\u00A0that\u00C2\u00A0the\u00C2\u00A0iron\u00C2\u00A0oxide\u00C2\u00A0(gossan)\u00C2\u00A0yielded\u00C2\u00A0anomalous\u00C2\u00A0base\u00C2\u00A0 metal\u00C2\u00A0and\u00C2\u00A0silver\u00C2\u00A0values\u00C2\u00A0(Injoque\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01979).\u00C2\u00A0\u00C2\u00A0Susequent\u00C2\u00A0drilling\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0self\u00E2\u0080\u0090potential\u00C2\u00A0geophysical\u00C2\u00A0 target\u00C2\u00A0in\u00C2\u00A01978\u00C2\u00A0led\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0discovery\u00C2\u00A0of\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0mineralization\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A0TG1\u00C2\u00A0deposit.\u00C2\u00A0\u00C2\u00A0 Based\u00C2\u00A0on\u00C2\u00A021\u00C2\u00A0diamond\u00C2\u00A0drill\u00C2\u00A0holes,\u00C2\u00A0the\u00C2\u00A0BRGM\u00C2\u00A0reported\u00C2\u00A0an\u00C2\u00A0inferred\u00C2\u00A0resource\u00C2\u00A0of\u00C2\u00A042.3\u00C2\u00A0million\u00C2\u00A0 tonnes\u00C2\u00A0grading\u00C2\u00A02.04%\u00C2\u00A0Cu,\u00C2\u00A01.45%\u00C2\u00A0Zn,\u00C2\u00A00.35%\u00C2\u00A0Pb\u00C2\u00A0and\u00C2\u00A038.4\u00C2\u00A0g/t\u00C2\u00A0Ag\u00C2\u00A0(BRGM,\u00C2\u00A01981,\u00C2\u00A0in\u00C2\u00A0Tegart\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A0 2000).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Manhattan\u00C2\u00A0Minerals\u00C2\u00A0Corp.\u00C2\u00A0of\u00C2\u00A0Vancouver,\u00C2\u00A0Canada,\u00C2\u00A0became\u00C2\u00A0involved\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0project\u00C2\u00A0in\u00C2\u00A0 May,\u00C2\u00A01999.\u00C2\u00A0\u00C2\u00A0Re\u00E2\u0080\u0090assaying\u00C2\u00A0of\u00C2\u00A0selected\u00C2\u00A0drill\u00C2\u00A0core\u00C2\u00A0suggested\u00C2\u00A0potential\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0overlying\u00C2\u00A0oxide\u00C2\u00A0zone\u00C2\u00A0 at\u00C2\u00A0TG1\u00C2\u00A0to\u00C2\u00A0contain\u00C2\u00A0significant\u00C2\u00A0precious\u00C2\u00A0metals.\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0gravity\u00C2\u00A0survey,\u00C2\u00A0followed\u00C2\u00A0by\u00C2\u00A0additional\u00C2\u00A0drilling,\u00C2\u00A0 resulted\u00C2\u00A0in\u00C2\u00A0an\u00C2\u00A0increased\u00C2\u00A0resource\u00C2\u00A0at\u00C2\u00A0TG1\u00C2\u00A0as\u00C2\u00A0well\u00C2\u00A0as\u00C2\u00A0the\u00C2\u00A0discovery\u00C2\u00A0of\u00C2\u00A0two\u00C2\u00A0other\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0 deposits,\u00C2\u00A0TG3\u00C2\u00A0and\u00C2\u00A0B5\u00C2\u00A0(Table\u00C2\u00A02),\u00C2\u00A0approximately\u00C2\u00A00.5\u00C2\u00A0and\u00C2\u00A012\u00C2\u00A0km\u00C2\u00A0south\u00C2\u00A0of\u00C2\u00A0TG1,\u00C2\u00A0respectively\u00C2\u00A0(Tegart\u00C2\u00A0 et\u00C2\u00A0al.,\u00C2\u00A02000).\u00C2\u00A0\u00C2\u00A0An\u00C2\u00A0updated\u00C2\u00A0resource\u00C2\u00A0was\u00C2\u00A0defined\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0TG1\u00C2\u00A0sulphide\u00C2\u00A0deposit,\u00C2\u00A0and\u00C2\u00A0new\u00C2\u00A0 resources\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0TG1\u00C2\u00A0oxide\u00C2\u00A0and\u00C2\u00A0TG3\u00C2\u00A0sulphide\u00C2\u00A0deposits,\u00C2\u00A0were\u00C2\u00A0reported\u00C2\u00A0in\u00C2\u00A02002\u00C2\u00A0(Table\u00C2\u00A01).\u00C2\u00A0\u00C2\u00A0 However,\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0socio\u00E2\u0080\u0090political\u00C2\u00A0issues\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A0local\u00C2\u00A0and\u00C2\u00A0regional\u00C2\u00A0level,\u00C2\u00A0which\u00C2\u00A0ultimately\u00C2\u00A0led\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0 destruction\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0company\u00E2\u0080\u0099s\u00C2\u00A0camp\u00C2\u00A0in\u00C2\u00A0early\u00C2\u00A02001,\u00C2\u00A0Manhattan\u00C2\u00A0lost\u00C2\u00A0title\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0project\u00C2\u00A0in\u00C2\u00A02004.\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0Tambogrande\u00C2\u00A0deposits\u00C2\u00A0remain\u00C2\u00A0undeveloped\u00C2\u00A0and\u00C2\u00A0there\u00C2\u00A0is\u00C2\u00A0presently\u00C2\u00A0no\u00C2\u00A0known\u00C2\u00A0active\u00C2\u00A0 exploration\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0area.\u00C2\u00A0 Chapter\u00C2\u00A01\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A04\u00C2\u00A0 Detailed\u00C2\u00A0reports\u00C2\u00A0related\u00C2\u00A0to\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0northwestern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0provide\u00C2\u00A0excellent\u00C2\u00A0 documentation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0but\u00C2\u00A0are\u00C2\u00A0limited\u00C2\u00A0in\u00C2\u00A0scope\u00C2\u00A0and\u00C2\u00A0have\u00C2\u00A0not\u00C2\u00A0 evaluated\u00C2\u00A0the\u00C2\u00A0broader\u00C2\u00A0regional\u00C2\u00A0geologic\u00C2\u00A0setting\u00C2\u00A0(Tegart\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A02000;\u00C2\u00A0Injoque\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01979).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 1.4\u00C2\u00A0 VMS\u00C2\u00A0Deposit\u00C2\u00A0Classification\u00C2\u00A0and\u00C2\u00A0Genetic\u00C2\u00A0Models\u00C2\u00A0 Volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0(Franklin\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01981;\u00C2\u00A0Lydon,\u00C2\u00A01984,\u00C2\u00A01988;\u00C2\u00A0 Ohmoto,\u00C2\u00A01996;\u00C2\u00A0Barrie\u00C2\u00A0and\u00C2\u00A0Hannington,\u00C2\u00A01999),\u00C2\u00A0also\u00C2\u00A0commonly\u00C2\u00A0termed\u00C2\u00A0\u00E2\u0080\u0098volcanic\u00E2\u0080\u0090hosted\u00C2\u00A0massive\u00C2\u00A0 sulphide\u00E2\u0080\u0099\u00C2\u00A0deposits\u00C2\u00A0(VHMS,\u00C2\u00A0Large,\u00C2\u00A01992),\u00C2\u00A0are\u00C2\u00A0\u00E2\u0080\u0098strata\u00E2\u0080\u0090bound\u00C2\u00A0accumulations\u00C2\u00A0of\u00C2\u00A0sulphide\u00C2\u00A0minerals\u00C2\u00A0 that\u00C2\u00A0precipitated\u00C2\u00A0at\u00C2\u00A0or\u00C2\u00A0near\u00C2\u00A0the\u00C2\u00A0sea\u00C2\u00A0floor\u00C2\u00A0in\u00C2\u00A0spatial,\u00C2\u00A0temporal,\u00C2\u00A0and\u00C2\u00A0genetic\u00C2\u00A0association\u00C2\u00A0with\u00C2\u00A0 contemporaneous\u00C2\u00A0volcanism\u00E2\u0080\u0099\u00C2\u00A0(Franklin\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02005).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0broadly\u00C2\u00A0accepted\u00C2\u00A0genetic\u00C2\u00A0model,\u00C2\u00A0 based\u00C2\u00A0mostly\u00C2\u00A0on\u00C2\u00A0empirical\u00C2\u00A0observations\u00C2\u00A0from\u00C2\u00A0ancient\u00C2\u00A0land\u00E2\u0080\u0090based\u00C2\u00A0and\u00C2\u00A0modern\u00C2\u00A0seafloor\u00C2\u00A0systems,\u00C2\u00A0 considers\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0to\u00C2\u00A0be\u00C2\u00A0the\u00C2\u00A0products\u00C2\u00A0of\u00C2\u00A0district\u00E2\u0080\u0090scale\u00C2\u00A0hydrothermal\u00C2\u00A0convection\u00C2\u00A0resulting\u00C2\u00A0 from\u00C2\u00A0anomalous\u00C2\u00A0thermal\u00C2\u00A0input\u00C2\u00A0into\u00C2\u00A0the\u00C2\u00A0shallow\u00C2\u00A0crust\u00C2\u00A0(Fig.\u00C2\u00A01.2;\u00C2\u00A0Franklin\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02005).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Down\u00E2\u0080\u0090drawn\u00C2\u00A0seawater\u00C2\u00A0is\u00C2\u00A0the\u00C2\u00A0primary\u00C2\u00A0component\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0hydrothermal\u00C2\u00A0fluid\u00C2\u00A0and\u00C2\u00A0heat\u00E2\u0080\u0090 induced\u00C2\u00A0fluid\u00E2\u0080\u0090rock\u00C2\u00A0reactions\u00C2\u00A0facilitate\u00C2\u00A0the\u00C2\u00A0transfer\u00C2\u00A0of\u00C2\u00A0metals\u00C2\u00A0and\u00C2\u00A0sulphur\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0substrate\u00C2\u00A0into\u00C2\u00A0 the\u00C2\u00A0convecting\u00C2\u00A0hydrothermal\u00C2\u00A0system\u00C2\u00A0(Franklin\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02005).\u00C2\u00A0\u00C2\u00A0Reduced\u00C2\u00A0seawater\u00C2\u00A0sulphate\u00C2\u00A0may\u00C2\u00A0 constitute\u00C2\u00A0a\u00C2\u00A0minor\u00C2\u00A0sulphur\u00C2\u00A0component\u00C2\u00A0in\u00C2\u00A0VMS\u00C2\u00A0sulphides.\u00C2\u00A0\u00C2\u00A0Chloride\u00C2\u00A0complexing\u00C2\u00A0is\u00C2\u00A0considered\u00C2\u00A0 responsible\u00C2\u00A0for\u00C2\u00A0most\u00C2\u00A0metal\u00C2\u00A0transport\u00C2\u00A0with\u00C2\u00A0precipitation\u00C2\u00A0triggered\u00C2\u00A0by\u00C2\u00A0cooling.\u00C2\u00A0\u00C2\u00A0To\u00C2\u00A0a\u00C2\u00A0much\u00C2\u00A0lesser\u00C2\u00A0 amount\u00C2\u00A0bi\u00E2\u0080\u0090sulphide\u00C2\u00A0complexes\u00C2\u00A0are\u00C2\u00A0thought\u00C2\u00A0to\u00C2\u00A0also\u00C2\u00A0play\u00C2\u00A0a\u00C2\u00A0role\u00C2\u00A0as\u00C2\u00A0transporting\u00C2\u00A0agent,\u00C2\u00A0especially\u00C2\u00A0 for\u00C2\u00A0Au,\u00C2\u00A0with\u00C2\u00A0oxidation\u00C2\u00A0causing\u00C2\u00A0metal\u00C2\u00A0precipitation\u00C2\u00A0(Hannington\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01995).\u00C2\u00A0\u00C2\u00A0Mixing\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0metal\u00E2\u0080\u0090 bearing\u00C2\u00A0hydrothermal\u00C2\u00A0fluid\u00C2\u00A0with\u00C2\u00A0cool\u00C2\u00A0(\u00C2\u00B1\u00C2\u00A0oxidized)\u00C2\u00A0seawater\u00C2\u00A0at\u00C2\u00A0or\u00C2\u00A0near\u00C2\u00A0the\u00C2\u00A0seafloor\u00C2\u00A0is\u00C2\u00A0the\u00C2\u00A0primary\u00C2\u00A0 method\u00C2\u00A0for\u00C2\u00A0sulphide\u00C2\u00A0deposition\u00C2\u00A0(Franklin\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02005).\u00C2\u00A0\u00C2\u00A0Some\u00C2\u00A0VMS\u00C2\u00A0models\u00C2\u00A0invoke\u00C2\u00A0high\u00E2\u0080\u0090level\u00C2\u00A0 intrusive\u00C2\u00A0phases\u00C2\u00A0as\u00C2\u00A0heat\u00C2\u00A0sources\u00C2\u00A0and\u00C2\u00A0include\u00C2\u00A0magmatic\u00E2\u0080\u0090derived\u00C2\u00A0fluid\u00C2\u00A0as\u00C2\u00A0an\u00C2\u00A0additional\u00C2\u00A0metals\u00C2\u00A0 source\u00C2\u00A0(Galley,\u00C2\u00A01993;\u00C2\u00A0Franklin\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01981).\u00C2\u00A0\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0are\u00C2\u00A0broadly\u00C2\u00A0syngenetic\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0host\u00C2\u00A0 Chapter\u00C2\u00A01\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A05\u00C2\u00A0 rock\u00C2\u00A0assemblages,\u00C2\u00A0which\u00C2\u00A0vary\u00C2\u00A0from\u00C2\u00A0volcanic\u00E2\u0080\u0090\u00C2\u00A0to\u00C2\u00A0sediment\u00E2\u0080\u0090dominated\u00C2\u00A0(Barrie\u00C2\u00A0and\u00C2\u00A0Hannington,\u00C2\u00A0 1999).\u00C2\u00A0\u00C2\u00A0Extensional\u00C2\u00A0basins\u00C2\u00A0are\u00C2\u00A0integral\u00C2\u00A0to\u00C2\u00A0nearly\u00C2\u00A0all\u00C2\u00A0VMS\u00C2\u00A0settings\u00C2\u00A0for\u00C2\u00A0two\u00C2\u00A0main\u00C2\u00A0reasons:\u00C2\u00A0(i)\u00C2\u00A0the\u00C2\u00A0 heat\u00C2\u00A0transfer\u00C2\u00A0into\u00C2\u00A0the\u00C2\u00A0upper\u00C2\u00A0crust\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0intrusion\u00C2\u00A0and\u00C2\u00A0advection\u00C2\u00A0of\u00C2\u00A0magma\u00C2\u00A0into\u00C2\u00A0attenuated\u00C2\u00A0 and\u00C2\u00A0extended\u00C2\u00A0crust;\u00C2\u00A0and\u00C2\u00A0(ii)\u00C2\u00A0the\u00C2\u00A0development\u00C2\u00A0of\u00C2\u00A0normal\u00C2\u00A0faults\u00C2\u00A0which\u00C2\u00A0channel\u00C2\u00A0hydrothermal\u00C2\u00A0 fluids\u00C2\u00A0and\u00C2\u00A0focus\u00C2\u00A0the\u00C2\u00A0deposition\u00C2\u00A0of\u00C2\u00A0sulphide\u00C2\u00A0minerals.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0geometries\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0vary\u00C2\u00A0significantly,\u00C2\u00A0but\u00C2\u00A0many\u00C2\u00A0occur\u00C2\u00A0as\u00C2\u00A0mounds\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0 seafloor,\u00C2\u00A0such\u00C2\u00A0as\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A0TAG\u00C2\u00A0hydrothermal\u00C2\u00A0mound\u00C2\u00A0(Fig.\u00C2\u00A01.3)(Herzig\u00C2\u00A0and\u00C2\u00A0Hannington,\u00C2\u00A01995).\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0 the\u00C2\u00A0rock\u00C2\u00A0record,\u00C2\u00A0deposits\u00C2\u00A0may\u00C2\u00A0be\u00C2\u00A0bulbous\u00C2\u00A0to\u00C2\u00A0tabular\u00C2\u00A0lenses\u00C2\u00A0of\u00C2\u00A0massive\u00C2\u00A0sulphide,\u00C2\u00A0i.e.,\u00C2\u00A060\u00E2\u0080\u0090100%\u00C2\u00A0 sulphide\u00C2\u00A0minerals\u00C2\u00A0(Lydon\u00C2\u00A01984),\u00C2\u00A0underlain\u00C2\u00A0by\u00C2\u00A0discordant\u00C2\u00A0zones\u00C2\u00A0of\u00C2\u00A0veined\u00C2\u00A0(\u00E2\u0080\u0098stringer\u00E2\u0080\u0099\u00C2\u00A0or\u00C2\u00A0 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in\u00C2\u00A0the\u00C2\u00A0number\u00C2\u00A0of\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Late\u00C2\u00A0Archean\u00C2\u00A0and\u00C2\u00A0Early\u00C2\u00A0Proterozoic\u00C2\u00A0(Fig.\u00C2\u00A01.4).\u00C2\u00A0\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0 are\u00C2\u00A0more\u00C2\u00A0evenly\u00C2\u00A0distributed\u00C2\u00A0throughout\u00C2\u00A0the\u00C2\u00A0Phanerozoic\u00C2\u00A0when\u00C2\u00A0compared\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0Precambrian\u00C2\u00A0 with\u00C2\u00A0the\u00C2\u00A0notable\u00C2\u00A0abundance\u00C2\u00A0of\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0early\u00C2\u00A0Paleozoic\u00C2\u00A0(Fig.\u00C2\u00A01.4).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0Tambogrande\u00C2\u00A0 deposits\u00C2\u00A0occur\u00C2\u00A0during\u00C2\u00A0a\u00C2\u00A0period\u00C2\u00A0of\u00C2\u00A0increased,\u00C2\u00A0but\u00C2\u00A0not\u00C2\u00A0prolific,\u00C2\u00A0VMS\u00C2\u00A0formation.\u00C2\u00A0\u00C2\u00A0Classification\u00C2\u00A0of\u00C2\u00A0 massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0is\u00C2\u00A0most\u00C2\u00A0effective\u00C2\u00A0using\u00C2\u00A0the\u00C2\u00A0lithostratigraphy\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0host\u00C2\u00A0assemblage\u00C2\u00A0 (Barrie\u00C2\u00A0and\u00C2\u00A0Hannington,\u00C2\u00A01999;\u00C2\u00A0Franklin\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02005).\u00C2\u00A0\u00C2\u00A0Bimodal\u00E2\u0080\u0090mafic\u00C2\u00A0deposits,\u00C2\u00A0which\u00C2\u00A0exemplify\u00C2\u00A0 those\u00C2\u00A0at\u00C2\u00A0Tambogrande,\u00C2\u00A0are\u00C2\u00A0characterized\u00C2\u00A0by\u00C2\u00A0volcanic\u00E2\u0080\u0090dominated\u00C2\u00A0stratigraphic\u00C2\u00A0sequences\u00C2\u00A0 consisting\u00C2\u00A0largely\u00C2\u00A0of\u00C2\u00A0basalt\u00C2\u00A0and\u00C2\u00A0>3\u00E2\u0080\u009025%\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0Other\u00C2\u00A0examples\u00C2\u00A0of\u00C2\u00A0large\u00C2\u00A0VMS\u00C2\u00A0 deposits\u00C2\u00A0from\u00C2\u00A0this\u00C2\u00A0class\u00C2\u00A0occur\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Archean,\u00C2\u00A0including\u00C2\u00A0the\u00C2\u00A0Noranda\u00C2\u00A0camp\u00C2\u00A0(Gibson\u00C2\u00A0and\u00C2\u00A0 Watkinson,\u00C2\u00A01990)\u00C2\u00A0and\u00C2\u00A0Kidd\u00C2\u00A0Creek\u00C2\u00A0(Hannington\u00C2\u00A0and\u00C2\u00A0Barrie,\u00C2\u00A01999),\u00C2\u00A0the\u00C2\u00A0Proterozoic,\u00C2\u00A0such\u00C2\u00A0as\u00C2\u00A0Flin\u00C2\u00A0 Chapter\u00C2\u00A01\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A06\u00C2\u00A0 Flon\u00C2\u00A0(Syme\u00C2\u00A0and\u00C2\u00A0Bailes,\u00C2\u00A01993)\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0Phanerozoic,\u00C2\u00A0such\u00C2\u00A0as\u00C2\u00A0the\u00C2\u00A0Urals\u00C2\u00A0deposits\u00C2\u00A0of\u00C2\u00A0Sibai\u00C2\u00A0and\u00C2\u00A0Gai\u00C2\u00A0 (Herrington\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02005).\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0Latin\u00C2\u00A0America,\u00C2\u00A0significantly\u00C2\u00A0large\u00C2\u00A0bimodal\u00E2\u0080\u0090mafic\u00E2\u0080\u0090type\u00C2\u00A0Jurassic\u00E2\u0080\u0090 Cretaceous\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0occur\u00C2\u00A0at\u00C2\u00A0Cerro\u00C2\u00A0Lindo\u00C2\u00A0in\u00C2\u00A0central\u00E2\u0080\u0090western\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0(Ly\u00C2\u00A0Zevallos,\u00C2\u00A02000)\u00C2\u00A0and\u00C2\u00A0 at\u00C2\u00A0San\u00C2\u00A0Nicolas,\u00C2\u00A0central\u00C2\u00A0Mexico\u00C2\u00A0(Johnson\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02000;\u00C2\u00A0Danielson,\u00C2\u00A02000).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Giant\u00C2\u00A0VMS\u00C2\u00A0Deposits\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0Tambogrande\u00C2\u00A0VMS\u00C2\u00A0district\u00C2\u00A0hosts\u00C2\u00A0three\u00C2\u00A0known\u00C2\u00A0deposits\u00C2\u00A0located\u00C2\u00A0near\u00C2\u00A0and\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0 south\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0village\u00C2\u00A0of\u00C2\u00A0Tambogrande\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Piura\u00C2\u00A0district\u00C2\u00A0of\u00C2\u00A0northwestern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0(Fig.\u00C2\u00A01.1).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0 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50\u00C2\u00A0Mt\u00C2\u00A0of\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0ore,\u00C2\u00A0whereas\u00C2\u00A0supergiants\u00C2\u00A0are\u00C2\u00A0often\u00C2\u00A0ascribed\u00C2\u00A0to\u00C2\u00A0deposits\u00C2\u00A0containing\u00C2\u00A0 more\u00C2\u00A0than\u00C2\u00A0>100\u00C2\u00A0Mt\u00C2\u00A0(Barrie\u00C2\u00A0and\u00C2\u00A0Hannington,\u00C2\u00A01999).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0Tambogrande\u00C2\u00A0deposits\u00C2\u00A0are\u00C2\u00A0the\u00C2\u00A0largest\u00C2\u00A0 of\u00C2\u00A0the\u00C2\u00A0Mesozoic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0and\u00C2\u00A0represent\u00C2\u00A0the\u00C2\u00A0most\u00C2\u00A0significant\u00C2\u00A0group\u00C2\u00A0of\u00C2\u00A0 VMS\u00C2\u00A0deposits\u00C2\u00A0of\u00C2\u00A0continental\u00C2\u00A0South\u00C2\u00A0America.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Grade\u00C2\u00A0and\u00C2\u00A0tonnage\u00C2\u00A0estimates\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0deposits\u00C2\u00A0are\u00C2\u00A0listed\u00C2\u00A0in\u00C2\u00A0Table\u00C2\u00A01.\u00C2\u00A0\u00C2\u00A0No\u00C2\u00A0resource\u00C2\u00A0estimate\u00C2\u00A0 is\u00C2\u00A0available\u00C2\u00A0for\u00C2\u00A0B5,\u00C2\u00A0but\u00C2\u00A0the\u00C2\u00A0deposit\u00C2\u00A0had\u00C2\u00A0drillhole\u00C2\u00A0intersections\u00C2\u00A0of\u00C2\u00A0up\u00C2\u00A0to\u00C2\u00A0280\u00C2\u00A0m\u00C2\u00A0of\u00C2\u00A0massive\u00C2\u00A0 sulphide\u00C2\u00A0at\u00C2\u00A0similar\u00C2\u00A0grades\u00C2\u00A0to\u00C2\u00A0TG1\u00C2\u00A0and\u00C2\u00A0TG3\u00C2\u00A0(Tegart\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02000).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0TG1\u00C2\u00A0deposit\u00C2\u00A0also\u00C2\u00A0has\u00C2\u00A0an\u00C2\u00A0 associated\u00C2\u00A0supergene\u00C2\u00A0oxide\u00C2\u00A0zone\u00C2\u00A0(Table\u00C2\u00A01).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 1.5\u00C2\u00A0 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nature/source\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0hydrothermal\u00C2\u00A0fluids\u00C2\u00A0and\u00C2\u00A0(B)\u00C2\u00A0the\u00C2\u00A0depositional\u00C2\u00A0seafloor\u00C2\u00A0environment.\u00C2\u00A0\u00C2\u00A0With\u00C2\u00A0 Chapter\u00C2\u00A01\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A07\u00C2\u00A0 respect\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0hydrothermal\u00C2\u00A0fluids,\u00C2\u00A0several\u00C2\u00A0variables\u00C2\u00A0could\u00C2\u00A0account\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0delivery\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0 significant\u00C2\u00A0amount\u00C2\u00A0of\u00C2\u00A0metal\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0seafloor\u00C2\u00A0environment.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0possibilities\u00C2\u00A0include\u00C2\u00A0(i)\u00C2\u00A0a\u00C2\u00A0long\u00E2\u0080\u0090 lived\u00C2\u00A0hydrothermal\u00C2\u00A0system\u00C2\u00A0allowing\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0protracted\u00C2\u00A0delivery\u00C2\u00A0of\u00C2\u00A0metalliferous\u00C2\u00A0hydrothermal\u00C2\u00A0 fluid\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0site\u00C2\u00A0of\u00C2\u00A0deposition.\u00C2\u00A0\u00C2\u00A0For\u00C2\u00A0instance,\u00C2\u00A0based\u00C2\u00A0on\u00C2\u00A0heat\u00C2\u00A0and\u00C2\u00A0fluid\u00E2\u0080\u0090flow\u00C2\u00A0modeling,\u00C2\u00A0Barrie\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0 (1999)\u00C2\u00A0proposed\u00C2\u00A0that\u00C2\u00A0the\u00C2\u00A0supergiant\u00C2\u00A0Kidd\u00C2\u00A0Creek\u00C2\u00A0ore\u00C2\u00A0body\u00C2\u00A0(~200\u00C2\u00A0Mt)\u00C2\u00A0could\u00C2\u00A0have\u00C2\u00A0formed\u00C2\u00A0in\u00C2\u00A0 650,000\u00C2\u00A0years,\u00C2\u00A0whereas\u00C2\u00A0modern\u00C2\u00A0ocean\u00C2\u00A0ridge\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0(~1\u00C2\u00A0Mt)\u00C2\u00A0are\u00C2\u00A0estimated\u00C2\u00A0 to\u00C2\u00A0have\u00C2\u00A0formed\u00C2\u00A0in\u00C2\u00A0less\u00C2\u00A0than\u00C2\u00A0100,000\u00C2\u00A0years\u00C2\u00A0(Rona,\u00C2\u00A01988).\u00C2\u00A0\u00C2\u00A0(ii)\u00C2\u00A0Discharge\u00C2\u00A0rates\u00C2\u00A0at\u00C2\u00A0hydrothermal\u00C2\u00A0 vents\u00C2\u00A0are\u00C2\u00A0also\u00C2\u00A0important\u00C2\u00A0and\u00C2\u00A0depend\u00C2\u00A0on\u00C2\u00A0a\u00C2\u00A0number\u00C2\u00A0of\u00C2\u00A0variables,\u00C2\u00A0namely\u00C2\u00A0the\u00C2\u00A0rate\u00C2\u00A0of\u00C2\u00A0heat\u00C2\u00A0loss\u00C2\u00A0 (heat\u00C2\u00A0flux)\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0amount\u00C2\u00A0of\u00C2\u00A0fluid\u00C2\u00A0available.\u00C2\u00A0\u00C2\u00A0Heat\u00C2\u00A0and\u00C2\u00A0fluid\u00C2\u00A0fluxes\u00C2\u00A0are\u00C2\u00A0largely\u00C2\u00A0dependent\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0 distance\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0heat\u00C2\u00A0source\u00C2\u00A0(in\u00C2\u00A0a\u00C2\u00A0convection\u00C2\u00A0model)\u00C2\u00A0or\u00C2\u00A0the\u00C2\u00A0size\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0intrusion\u00C2\u00A0(magmatic\u00E2\u0080\u0090 hydrothermal\u00C2\u00A0and\u00C2\u00A0convection\u00C2\u00A0models).\u00C2\u00A0\u00C2\u00A0Ultimately,\u00C2\u00A0permeability\u00C2\u00A0is\u00C2\u00A0the\u00C2\u00A0main\u00C2\u00A0control\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0fluid\u00C2\u00A0 flux\u00C2\u00A0and\u00C2\u00A0this\u00C2\u00A0is\u00C2\u00A0likely\u00C2\u00A0to\u00C2\u00A0be\u00C2\u00A0controlled\u00C2\u00A0by\u00C2\u00A0both\u00C2\u00A0the\u00C2\u00A0style\u00C2\u00A0and\u00C2\u00A0degree\u00C2\u00A0of\u00C2\u00A0structural\u00C2\u00A0deformation\u00C2\u00A0as\u00C2\u00A0 well\u00C2\u00A0as\u00C2\u00A0primary\u00C2\u00A0lithological\u00C2\u00A0features.\u00C2\u00A0\u00C2\u00A0(iii)\u00C2\u00A0Finally,\u00C2\u00A0metal\u00C2\u00A0concentrations\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0hydrothermal\u00C2\u00A0 fluids\u00C2\u00A0may\u00C2\u00A0be\u00C2\u00A0of\u00C2\u00A0critical\u00C2\u00A0importance.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0a\u00C2\u00A0magmatic\u00C2\u00A0model,\u00C2\u00A0the\u00C2\u00A0metal\u00C2\u00A0concentration\u00C2\u00A0depends\u00C2\u00A0on\u00C2\u00A0 the\u00C2\u00A0composition\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0intrusion,\u00C2\u00A0metal\u00C2\u00A0partitioning\u00C2\u00A0into\u00C2\u00A0a\u00C2\u00A0volatile\u00C2\u00A0phase,\u00C2\u00A0and\u00C2\u00A0source\u00C2\u00A0of\u00C2\u00A0ligands\u00C2\u00A0 to\u00C2\u00A0transport\u00C2\u00A0metals.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0a\u00C2\u00A0convection\u00C2\u00A0system\u00C2\u00A0fluid\u00E2\u0080\u0090rock\u00C2\u00A0reactions\u00C2\u00A0are\u00C2\u00A0of\u00C2\u00A0key\u00C2\u00A0importance,\u00C2\u00A0wherein\u00C2\u00A0 the\u00C2\u00A0amount\u00C2\u00A0of\u00C2\u00A0rock\u00C2\u00A0available\u00C2\u00A0for\u00C2\u00A0leaching\u00C2\u00A0(size\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0system),\u00C2\u00A0metal\u00C2\u00A0contents\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0source\u00C2\u00A0 rocks,\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0effectiveness\u00C2\u00A0the\u00C2\u00A0fluids\u00C2\u00A0to\u00C2\u00A0scavenge\u00C2\u00A0metals\u00C2\u00A0must\u00C2\u00A0be\u00C2\u00A0considered.\u00C2\u00A0 The\u00C2\u00A0depositional\u00C2\u00A0site\u00C2\u00A0for\u00C2\u00A0sulphides\u00C2\u00A0at\u00C2\u00A0or\u00C2\u00A0below\u00C2\u00A0the\u00C2\u00A0seafloor\u00C2\u00A0must\u00C2\u00A0also\u00C2\u00A0be\u00C2\u00A0conducive\u00C2\u00A0to\u00C2\u00A0 efficient\u00C2\u00A0sulphide\u00C2\u00A0precipitation\u00C2\u00A0and\u00C2\u00A0preservation.\u00C2\u00A0\u00C2\u00A0Only\u00C2\u00A0a\u00C2\u00A0relatively\u00C2\u00A0small\u00C2\u00A0portion\u00C2\u00A0(<1\u00E2\u0080\u00935%)\u00C2\u00A0of\u00C2\u00A0 metals\u00C2\u00A0emitted\u00C2\u00A0from\u00C2\u00A0modern\u00C2\u00A0seafloor\u00C2\u00A0hydrothermal\u00C2\u00A0vents\u00C2\u00A0are\u00C2\u00A0actually\u00C2\u00A0precipitated\u00C2\u00A0(Converse\u00C2\u00A0 et\u00C2\u00A0al.,\u00C2\u00A01984;\u00C2\u00A0Feely\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01994).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0remainder\u00C2\u00A0are\u00C2\u00A0vented\u00C2\u00A0into\u00C2\u00A0the\u00C2\u00A0ocean\u00C2\u00A0column\u00C2\u00A0and\u00C2\u00A0 dispersed.\u00C2\u00A0\u00C2\u00A0Sub\u00E2\u0080\u0090seafloor\u00C2\u00A0sulphide\u00C2\u00A0precipitation\u00C2\u00A0as\u00C2\u00A0replacement\u00C2\u00A0of\u00C2\u00A0relatively\u00C2\u00A0permeable\u00C2\u00A0strata\u00C2\u00A0is\u00C2\u00A0 Chapter\u00C2\u00A01\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A08\u00C2\u00A0 a\u00C2\u00A0common\u00C2\u00A0feature\u00C2\u00A0to\u00C2\u00A0VMS\u00C2\u00A0mineralization\u00C2\u00A0(Doyle\u00C2\u00A0and\u00C2\u00A0Allen,\u00C2\u00A02003)\u00C2\u00A0and\u00C2\u00A0has\u00C2\u00A0been\u00C2\u00A0recognized\u00C2\u00A0at\u00C2\u00A0 the\u00C2\u00A0Horne\u00C2\u00A0(Kerr\u00C2\u00A0and\u00C2\u00A0Gibson,\u00C2\u00A01993)\u00C2\u00A0and\u00C2\u00A0Kidd\u00C2\u00A0Creek\u00C2\u00A0deposits\u00C2\u00A0(Hannington\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01999).\u00C2\u00A0\u00C2\u00A0Ambient\u00C2\u00A0 oceanic\u00C2\u00A0environmental\u00C2\u00A0conditions\u00C2\u00A0are\u00C2\u00A0especially\u00C2\u00A0important\u00C2\u00A0in\u00C2\u00A0some\u00C2\u00A0VMS\u00C2\u00A0settings.\u00C2\u00A0\u00C2\u00A0Eastoe\u00C2\u00A0and\u00C2\u00A0 Gustin\u00C2\u00A0(1996)\u00C2\u00A0suggest\u00C2\u00A0an\u00C2\u00A0association\u00C2\u00A0of\u00C2\u00A0Phanerozoic\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0with\u00C2\u00A0black\u00C2\u00A0shale,\u00C2\u00A0and\u00C2\u00A0hence\u00C2\u00A0 oceanic\u00C2\u00A0anoxia,\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0efficiency\u00C2\u00A0of\u00C2\u00A0sulphide\u00C2\u00A0precipitation\u00C2\u00A0and\u00C2\u00A0preservation\u00C2\u00A0in\u00C2\u00A0anoxic\u00C2\u00A0 seawater\u00C2\u00A0environments.\u00C2\u00A0\u00C2\u00A0Saez\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1999)\u00C2\u00A0argue\u00C2\u00A0that\u00C2\u00A0many\u00C2\u00A0giant\u00C2\u00A0to\u00C2\u00A0supergiant\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0 the\u00C2\u00A0Iberian\u00C2\u00A0Pyrite\u00C2\u00A0Belt\u00C2\u00A0(Portugal,\u00C2\u00A0Spain)\u00C2\u00A0are\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0black\u00C2\u00A0shale\u00C2\u00A0horizons\u00C2\u00A0formed\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0 euxinic\u00C2\u00A0environment\u00C2\u00A0and\u00C2\u00A0hence\u00C2\u00A0bacterial\u00C2\u00A0reduction\u00C2\u00A0occurred.\u00C2\u00A0\u00C2\u00A0Similarly,\u00C2\u00A0the\u00C2\u00A0supergiant\u00C2\u00A0 Brunswick\u00C2\u00A0No.\u00C2\u00A012\u00C2\u00A0deposit\u00C2\u00A0is\u00C2\u00A0considered\u00C2\u00A0to\u00C2\u00A0have\u00C2\u00A0been\u00C2\u00A0deposited\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0deeper\u00C2\u00A0segments\u00C2\u00A0of\u00C2\u00A0 a\u00C2\u00A0continental\u00C2\u00A0back\u00E2\u0080\u0090arc\u00C2\u00A0rift\u00C2\u00A0basin\u00C2\u00A0where\u00C2\u00A0bottom\u00C2\u00A0waters\u00C2\u00A0were\u00C2\u00A0anoxic\u00C2\u00A0and\u00C2\u00A0reducing\u00C2\u00A0conditions\u00C2\u00A0 ideal\u00C2\u00A0for\u00C2\u00A0VMS\u00C2\u00A0formation\u00C2\u00A0(Goodfellow\u00C2\u00A0and\u00C2\u00A0Peter,\u00C2\u00A01996).\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0the\u00C2\u00A0absence\u00C2\u00A0of\u00C2\u00A0anoxia,\u00C2\u00A0models\u00C2\u00A0 involving\u00C2\u00A0siliceous\u00C2\u00A0\u00E2\u0080\u0098caps\u00E2\u0080\u0099\u00C2\u00A0as\u00C2\u00A0protective\u00C2\u00A0barriers\u00C2\u00A0to\u00C2\u00A0oxidative\u00C2\u00A0waters\u00C2\u00A0have\u00C2\u00A0been\u00C2\u00A0proposed,\u00C2\u00A0such\u00C2\u00A0as\u00C2\u00A0 Aljustrel\u00C2\u00A0deposit\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0IPB\u00C2\u00A0(Barriga\u00C2\u00A0and\u00C2\u00A0Fyfe,\u00C2\u00A01988),\u00C2\u00A0as\u00C2\u00A0well\u00C2\u00A0as\u00C2\u00A0some\u00C2\u00A0modern\u00C2\u00A0seafloor\u00C2\u00A0deposits\u00C2\u00A0 where\u00C2\u00A0silica\u00E2\u0080\u0090producing\u00C2\u00A0bacteria\u00C2\u00A0have\u00C2\u00A0also\u00C2\u00A0been\u00C2\u00A0observed\u00C2\u00A0(Humphris\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01995).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 1.6\u00C2\u00A0 Thesis\u00C2\u00A0Objectives\u00C2\u00A0 Giant\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0are\u00C2\u00A0an\u00C2\u00A0enigma\u00C2\u00A0in\u00C2\u00A0that\u00C2\u00A0few\u00C2\u00A0VMS\u00C2\u00A0 districts\u00C2\u00A0contain\u00C2\u00A0such\u00C2\u00A0large\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0rarely\u00C2\u00A0is\u00C2\u00A0there\u00C2\u00A0more\u00C2\u00A0than\u00C2\u00A0one\u00C2\u00A0giant\u00C2\u00A0deposit\u00C2\u00A0within\u00C2\u00A0a\u00C2\u00A0 single\u00C2\u00A0camp.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0Tambogrande\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0of\u00C2\u00A0northwestern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0 represent\u00C2\u00A0an\u00C2\u00A0opportunity\u00C2\u00A0to\u00C2\u00A0evaluate\u00C2\u00A0the\u00C2\u00A0conditions\u00C2\u00A0which\u00C2\u00A0permit\u00C2\u00A0the\u00C2\u00A0generation\u00C2\u00A0of\u00C2\u00A0giant\u00C2\u00A0VMS\u00C2\u00A0 deposits.\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0main\u00C2\u00A0goal\u00C2\u00A0of\u00C2\u00A0this\u00C2\u00A0research\u00C2\u00A0is\u00C2\u00A0to\u00C2\u00A0place\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0 regional\u00C2\u00A0geological\u00C2\u00A0context\u00C2\u00A0and\u00C2\u00A0to\u00C2\u00A0explain\u00C2\u00A0the\u00C2\u00A0accompanying\u00C2\u00A0tectonomagmatic\u00C2\u00A0scenario\u00C2\u00A0 responsible\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0development\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin.\u00C2\u00A0\u00C2\u00A0Key\u00C2\u00A0to\u00C2\u00A0achieving\u00C2\u00A0these\u00C2\u00A0goals\u00C2\u00A0are\u00C2\u00A0(i)\u00C2\u00A0the\u00C2\u00A0 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the\u00C2\u00A0pristine\u00C2\u00A0preservation\u00C2\u00A0state\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0excellent\u00C2\u00A0three\u00C2\u00A0dimensional\u00C2\u00A0 geological\u00C2\u00A0database\u00C2\u00A0developed\u00C2\u00A0from\u00C2\u00A0diamond\u00C2\u00A0drill\u00C2\u00A0core\u00C2\u00A0logging,\u00C2\u00A0the\u00C2\u00A0thesis\u00C2\u00A0also\u00C2\u00A0aims\u00C2\u00A0to\u00C2\u00A0develop\u00C2\u00A0 a\u00C2\u00A0better\u00C2\u00A0understanding\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0local\u00C2\u00A0paleomorphological,\u00C2\u00A0volcanic\u00C2\u00A0and\u00C2\u00A0structural\u00C2\u00A0controls.\u00C2\u00A0\u00C2\u00A0 Documenting\u00C2\u00A0the\u00C2\u00A0local\u00C2\u00A0and\u00C2\u00A0regional\u00C2\u00A0geological\u00C2\u00A0attributes\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Tambogrande\u00C2\u00A0VMS\u00C2\u00A0setting\u00C2\u00A0help\u00C2\u00A0 establish\u00C2\u00A0the\u00C2\u00A0depositional\u00C2\u00A0environments\u00C2\u00A0and\u00C2\u00A0tectonic\u00C2\u00A0controls\u00C2\u00A0for\u00C2\u00A0giant\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0 deposits\u00C2\u00A0of\u00C2\u00A0this\u00C2\u00A0type,\u00C2\u00A0and\u00C2\u00A0establish\u00C2\u00A0a\u00C2\u00A0geologic\u00C2\u00A0framework\u00C2\u00A0for\u00C2\u00A0comparisons\u00C2\u00A0with\u00C2\u00A0similar\u00C2\u00A0VMS\u00C2\u00A0 settings.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 1.7\u00C2\u00A0 Methodology\u00C2\u00A0 1.7.1\u00C2\u00A0 Core\u00C2\u00A0Logging\u00C2\u00A0 \u00C2\u00A0 A\u00C2\u00A0total\u00C2\u00A0of\u00C2\u00A0441\u00C2\u00A0diamond\u00C2\u00A0drill\u00C2\u00A0holes\u00C2\u00A0and\u00C2\u00A0more\u00C2\u00A0than\u00C2\u00A080,000\u00C2\u00A0m\u00C2\u00A0of\u00C2\u00A0core,\u00C2\u00A0mostly\u00C2\u00A0from\u00C2\u00A0 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unstable\u00C2\u00A0political\u00C2\u00A0conditions.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0area\u00C2\u00A0had\u00C2\u00A0previously\u00C2\u00A0been\u00C2\u00A0mapped\u00C2\u00A0at\u00C2\u00A01:100,000\u00C2\u00A0by\u00C2\u00A0Reyes\u00C2\u00A0and\u00C2\u00A0 Caldas\u00C2\u00A0(1987)\u00C2\u00A0as\u00C2\u00A0part\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0large\u00C2\u00A0regional\u00C2\u00A0project.\u00C2\u00A0 Chapter\u00C2\u00A01\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A010\u00C2\u00A0 1.7.3\u00C2\u00A0 Geochronology\u00C2\u00A0 \u00C2\u00A0 U\u00E2\u0080\u0090Pb\u00C2\u00A0age\u00C2\u00A0determinations\u00C2\u00A0of\u00C2\u00A0volcanic\u00C2\u00A0and\u00C2\u00A0intrusive\u00C2\u00A0rocks\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0study\u00C2\u00A0area\u00C2\u00A0provide\u00C2\u00A0the\u00C2\u00A0 first\u00C2\u00A0known\u00C2\u00A0radiometric\u00C2\u00A0ages\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0region.\u00C2\u00A0\u00C2\u00A0Approximately\u00C2\u00A040\u00C2\u00A0samples\u00C2\u00A0of\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0 from\u00C2\u00A0drill\u00C2\u00A0core\u00C2\u00A0and\u00C2\u00A0outcrops\u00C2\u00A0were\u00C2\u00A0processed\u00C2\u00A0with\u00C2\u00A0about\u00C2\u00A025%\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0samples\u00C2\u00A0yielding\u00C2\u00A0sufficient\u00C2\u00A0 zircons\u00C2\u00A0for\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0isotope\u00C2\u00A0analysis.\u00C2\u00A0\u00C2\u00A0Samples\u00C2\u00A0were\u00C2\u00A0analyzed\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A0Pacific\u00C2\u00A0Centre\u00C2\u00A0for\u00C2\u00A0Isotopic\u00C2\u00A0and\u00C2\u00A0 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spectrometer\u00C2\u00A0(NGMS)\u00C2\u00A0technique\u00C2\u00A0at\u00C2\u00A0PCIGR.\u00C2\u00A0\u00C2\u00A0Details\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0methodology,\u00C2\u00A0precision\u00C2\u00A0and\u00C2\u00A0accuracy\u00C2\u00A0 are\u00C2\u00A0available\u00C2\u00A0in\u00C2\u00A0Appendices\u00C2\u00A0A\u00C2\u00A0&\u00C2\u00A0B\u00C2\u00A0and\u00C2\u00A0at\u00C2\u00A0 http://www.eos.ubc.ca/research/pcigr/Instrumentation.htm\u00C2\u00A0and\u00C2\u00A0 http://shrimprg.stanford.edu/.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 1.7.4\u00C2\u00A0 Lithogeochemistry\u00C2\u00A0 \u00C2\u00A0 Samples\u00C2\u00A0were\u00C2\u00A0collected\u00C2\u00A0from\u00C2\u00A0drill\u00C2\u00A0core\u00C2\u00A0and\u00C2\u00A0outcrop\u00C2\u00A0for\u00C2\u00A0whole\u00C2\u00A0rock\u00C2\u00A0major,\u00C2\u00A0trace\u00C2\u00A0and\u00C2\u00A0rare\u00C2\u00A0 earth\u00C2\u00A0element\u00C2\u00A0(REE)\u00C2\u00A0analysis.\u00C2\u00A0\u00C2\u00A0Limited\u00C2\u00A0lithogeochemical\u00C2\u00A0studies\u00C2\u00A0were\u00C2\u00A0reported\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0region\u00C2\u00A0 (Tegart\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02000).\u00C2\u00A0\u00C2\u00A0Analyses\u00C2\u00A0were\u00C2\u00A0carried\u00C2\u00A0out\u00C2\u00A0at\u00C2\u00A0ALS\u00C2\u00A0Chemex\u00C2\u00A0Laboratories,\u00C2\u00A0Vancouver,\u00C2\u00A0 Canada\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0Department\u00C2\u00A0of\u00C2\u00A0Earth\u00C2\u00A0Sciences\u00C2\u00A0at\u00C2\u00A0Memorial\u00C2\u00A0University,\u00C2\u00A0St.\u00C2\u00A0John\u00E2\u0080\u0099s,\u00C2\u00A0Canada,\u00C2\u00A0using\u00C2\u00A0 a\u00C2\u00A0combination\u00C2\u00A0of\u00C2\u00A0inductively\u00C2\u00A0coupled\u00C2\u00A0plasma\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A0mass\u00C2\u00A0spectrometry\u00C2\u00A0(ICP\u00E2\u0080\u0090MS)\u00C2\u00A0and\u00C2\u00A0inductively\u00C2\u00A0 coupled\u00C2\u00A0plasma\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0atomic\u00C2\u00A0emission\u00C2\u00A0spectrometry\u00C2\u00A0(ICP\u00E2\u0080\u0090AES).\u00C2\u00A0\u00C2\u00A0Details\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0methodology,\u00C2\u00A0 precision\u00C2\u00A0and\u00C2\u00A0accuracy\u00C2\u00A0are\u00C2\u00A0available\u00C2\u00A0in\u00C2\u00A0Appendix\u00C2\u00A0C\u00C2\u00A0and\u00C2\u00A0at\u00C2\u00A0 http://www.alschemex.com/learnmore/learnmore\u00E2\u0080\u0090techinfo\u00E2\u0080\u0090multielement\u00E2\u0080\u0090wholerock.htm\u00C2\u00A0and\u00C2\u00A0 http://www.mun.ca/earthsciences/ICPMS/Solution_ICP\u00E2\u0080\u0090MS.php.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Chapter\u00C2\u00A01\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A011\u00C2\u00A0 1.7.5\u00C2\u00A0 Isotope\u00C2\u00A0Chemistry\u00C2\u00A0 \u00C2\u00A0 Pb,\u00C2\u00A0Sm\u00E2\u0080\u0090Nd\u00C2\u00A0and\u00C2\u00A0Rb\u00E2\u0080\u0090Sr\u00C2\u00A0isotope\u00C2\u00A0geochemical\u00C2\u00A0data\u00C2\u00A0were\u00C2\u00A0utilized\u00C2\u00A0as\u00C2\u00A0tracers\u00C2\u00A0of\u00C2\u00A0relative\u00C2\u00A0 mantle\u00C2\u00A0and\u00C2\u00A0continental\u00C2\u00A0crust\u00C2\u00A0contributions\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0analyses\u00C2\u00A0of\u00C2\u00A0ore\u00C2\u00A0 samples\u00C2\u00A0were\u00C2\u00A0also\u00C2\u00A0carried\u00C2\u00A0out\u00C2\u00A0for\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0order\u00C2\u00A0to\u00C2\u00A0ascertain\u00C2\u00A0the\u00C2\u00A0source\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Pb\u00C2\u00A0(and\u00C2\u00A0 by\u00C2\u00A0inference\u00C2\u00A0other\u00C2\u00A0metals).\u00C2\u00A0\u00C2\u00A0All\u00C2\u00A0analyses\u00C2\u00A0were\u00C2\u00A0carried\u00C2\u00A0out\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A0PCIGR.\u00C2\u00A0\u00C2\u00A0Details\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 methodology\u00C2\u00A0are\u00C2\u00A0available\u00C2\u00A0at\u00C2\u00A0http://www.eos.ubc.ca/research/pcigr/Instrumentation.htm.\u00C2\u00A0\u00C2\u00A0 1.8\u00C2\u00A0 Presentation\u00C2\u00A0 \u00C2\u00A0 This\u00C2\u00A0study\u00C2\u00A0is\u00C2\u00A0presented\u00C2\u00A0as\u00C2\u00A0a\u00C2\u00A0series\u00C2\u00A0of\u00C2\u00A0research\u00C2\u00A0manuscripts\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0purpose\u00C2\u00A0of\u00C2\u00A0 publication\u00C2\u00A0in\u00C2\u00A0refereed\u00C2\u00A0professional\u00C2\u00A0journals\u00C2\u00A0pertaining\u00C2\u00A0to\u00C2\u00A0economic\u00C2\u00A0geology.\u00C2\u00A0\u00C2\u00A0As\u00C2\u00A0such,\u00C2\u00A0some\u00C2\u00A0 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core\u00C2\u00A0logging.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0chapter\u00C2\u00A0provides\u00C2\u00A0a\u00C2\u00A0report\u00C2\u00A0of\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0zircon\u00C2\u00A0ages\u00C2\u00A0for\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0 throughout\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0sequence\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin,\u00C2\u00A0as\u00C2\u00A0well\u00C2\u00A0as\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0zircon\u00C2\u00A0ages\u00C2\u00A0for\u00C2\u00A0 some\u00C2\u00A0intrusive\u00C2\u00A0phases\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0sequence.\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0are\u00C2\u00A0the\u00C2\u00A0first\u00C2\u00A0reported\u00C2\u00A0radiometric\u00C2\u00A0ages\u00C2\u00A0for\u00C2\u00A0 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the\u00C2\u00A0depositional\u00C2\u00A0setting\u00C2\u00A0and\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0provides\u00C2\u00A0a\u00C2\u00A0detailed\u00C2\u00A0analysis\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0immediate\u00C2\u00A0 VMS\u00E2\u0080\u0090hosting\u00C2\u00A0volcanic\u00C2\u00A0succession\u00C2\u00A0as\u00C2\u00A0well\u00C2\u00A0as\u00C2\u00A0reconstructed\u00C2\u00A0paleo\u00E2\u0080\u0090sea\u00E2\u0080\u0090floor\u00C2\u00A0models.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0chapter\u00C2\u00A0 utilizes\u00C2\u00A0geologic\u00C2\u00A0plans,\u00C2\u00A0sections\u00C2\u00A0and\u00C2\u00A0three\u00E2\u0080\u0090dimensional\u00C2\u00A0perspectives\u00C2\u00A0to\u00C2\u00A0recreate\u00C2\u00A0the\u00C2\u00A0submarine\u00C2\u00A0 structural\u00C2\u00A0and\u00C2\u00A0volcanic\u00C2\u00A0setting\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0TG1\u00C2\u00A0and\u00C2\u00A0TG3\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0emphasize\u00C2\u00A0the\u00C2\u00A0important\u00C2\u00A0role\u00C2\u00A0 of\u00C2\u00A0the\u00C2\u00A0local\u00C2\u00A0submarine\u00C2\u00A0volcanic\u00C2\u00A0environment\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0location\u00C2\u00A0and\u00C2\u00A0morphology\u00C2\u00A0and\u00C2\u00A0possibly\u00C2\u00A0the\u00C2\u00A0 size\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0VMS\u00C2\u00A0deposits.\u00C2\u00A0\u00C2\u00A0Tambogrande\u00C2\u00A0represents\u00C2\u00A0a\u00C2\u00A0rare\u00C2\u00A0occurrence\u00C2\u00A0of\u00C2\u00A0well\u00C2\u00A0preserved,\u00C2\u00A0giant\u00C2\u00A0 VMS\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0may\u00C2\u00A0serve\u00C2\u00A0as\u00C2\u00A0a\u00C2\u00A0physical\u00C2\u00A0model\u00C2\u00A0for\u00C2\u00A0similar\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0deformed\u00C2\u00A0terrains.\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0Volcanic\u00C2\u00A0rock\u00C2\u00A0geochemistry\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0tectonomagmatic\u00C2\u00A0setting\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0 deposits\u00C2\u00A0at\u00C2\u00A0Tambogrande,\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0this\u00C2\u00A0chapter\u00C2\u00A0evaluates\u00C2\u00A0the\u00C2\u00A0volcano\u00E2\u0080\u0090stratigraphic\u00C2\u00A0lithochemical\u00C2\u00A0 variations\u00C2\u00A0throughout\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0and\u00C2\u00A0demonstrates\u00C2\u00A0generally\u00C2\u00A0\u00E2\u0080\u0098oceanic\u00E2\u0080\u0099\u00C2\u00A0arc\u00E2\u0080\u0090like\u00C2\u00A0 geochemical\u00C2\u00A0signatures\u00C2\u00A0that\u00C2\u00A0vary\u00C2\u00A0from\u00C2\u00A0tholeiitic\u00C2\u00A0to\u00C2\u00A0weakly\u00C2\u00A0calc\u00E2\u0080\u0090alkaline.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0ocean\u00E2\u0080\u0090like\u00C2\u00A0 affinities\u00C2\u00A0reaffirm\u00C2\u00A0the\u00C2\u00A0tectonic\u00C2\u00A0setting\u00C2\u00A0as\u00C2\u00A0a\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0developed\u00C2\u00A0on\u00C2\u00A0very\u00C2\u00A0thin\u00C2\u00A0crust\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A0 leading\u00C2\u00A0edge\u00C2\u00A0of\u00C2\u00A0continental\u00C2\u00A0South\u00C2\u00A0America.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0data\u00C2\u00A0also\u00C2\u00A0invoke\u00C2\u00A0partial\u00C2\u00A0melting\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0crust\u00C2\u00A0as\u00C2\u00A0 the\u00C2\u00A0source\u00C2\u00A0for\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0VMS\u00C2\u00A0environment,\u00C2\u00A0consistent\u00C2\u00A0with\u00C2\u00A0a\u00C2\u00A0high\u00C2\u00A0heat\u00C2\u00A0flow\u00C2\u00A0 regime\u00C2\u00A0and\u00C2\u00A0favourable\u00C2\u00A0for\u00C2\u00A0VMS\u00C2\u00A0formation.\u00C2\u00A0 Chapter\u00C2\u00A05\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A0Pb\u00E2\u0080\u0090Sr\u00E2\u0080\u0090Nd\u00C2\u00A0isotope\u00C2\u00A0systematics\u00C2\u00A0of\u00C2\u00A0Cretaceous\u00C2\u00A0arc\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0 Lancones\u00C2\u00A0Basin\u00C2\u00A0near\u00C2\u00A0Tambogrande,\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A0Implications\u00C2\u00A0for\u00C2\u00A0VMS\u00C2\u00A0deposit\u00C2\u00A0models\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A0this\u00C2\u00A0chapter\u00C2\u00A0is\u00C2\u00A0 a\u00C2\u00A0tracer\u00C2\u00A0isotope\u00C2\u00A0study\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0hosting\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0and\u00C2\u00A0supports\u00C2\u00A0 the\u00C2\u00A0conclusions\u00C2\u00A0of\u00C2\u00A0Chapter\u00C2\u00A04\u00C2\u00A0regarding\u00C2\u00A0the\u00C2\u00A0tectonic\u00C2\u00A0setting\u00C2\u00A0and\u00C2\u00A0petrochemical\u00C2\u00A0evolution\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 volcanic\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin.\u00C2\u00A0\u00C2\u00A0Specifically,\u00C2\u00A0the\u00C2\u00A0data\u00C2\u00A0support\u00C2\u00A0a\u00C2\u00A0mantle\u00E2\u0080\u0090wedge\u00C2\u00A0source\u00C2\u00A0for\u00C2\u00A0 basalts\u00C2\u00A0but\u00C2\u00A0indicate\u00C2\u00A0continental\u00C2\u00A0crust\u00C2\u00A0was\u00C2\u00A0a\u00C2\u00A0factor\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0generation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Chapter\u00C2\u00A01\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A013\u00C2\u00A0 The\u00C2\u00A0data\u00C2\u00A0also\u00C2\u00A0permit\u00C2\u00A0tests\u00C2\u00A0of\u00C2\u00A0models\u00C2\u00A0relating\u00C2\u00A0igneous\u00C2\u00A0petrochemistry\u00C2\u00A0to\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0 suggests\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0do\u00C2\u00A0not\u00C2\u00A0contribute\u00C2\u00A0to\u00C2\u00A0metals\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0formation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0VMS\u00C2\u00A0deposits,\u00C2\u00A0 but\u00C2\u00A0are\u00C2\u00A0related\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0same\u00C2\u00A0thermal\u00C2\u00A0anomaly\u00C2\u00A0which\u00C2\u00A0enabled\u00C2\u00A0VMS\u00C2\u00A0formation.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Chapter\u00C2\u00A06\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A0Summary,\u00C2\u00A0Discussion\u00C2\u00A0and\u00C2\u00A0Unresolved\u00C2\u00A0Questions\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0summary\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0major\u00C2\u00A0 findings\u00C2\u00A0of\u00C2\u00A0this\u00C2\u00A0study\u00C2\u00A0with\u00C2\u00A0some\u00C2\u00A0discussions\u00C2\u00A0and\u00C2\u00A0elaboration\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0on\u00C2\u00A0key\u00C2\u00A0ideas.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0key\u00C2\u00A0 contributions\u00C2\u00A0of\u00C2\u00A0this\u00C2\u00A0research\u00C2\u00A0project\u00C2\u00A0include\u00C2\u00A0the\u00C2\u00A0following:\u00C2\u00A0(i)\u00C2\u00A0a\u00C2\u00A0comprehensive\u00C2\u00A0baseline\u00C2\u00A0 documentation\u00C2\u00A0of\u00C2\u00A0an\u00C2\u00A0economically\u00C2\u00A0significant\u00C2\u00A0VMS\u00C2\u00A0district;\u00C2\u00A0(ii)\u00C2\u00A0a\u00C2\u00A0better\u00C2\u00A0understanding\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 Cretaceous\u00C2\u00A0geology\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0northwest\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0Andean\u00C2\u00A0segment\u00C2\u00A0and\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0metallogenesis\u00C2\u00A0within\u00C2\u00A0 the\u00C2\u00A0marginal\u00C2\u00A0basins\u00C2\u00A0of\u00C2\u00A0Per\u00C3\u00BA;\u00C2\u00A0(iii)\u00C2\u00A0the\u00C2\u00A0reconstruction\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0paleo\u00E2\u0080\u0090depositional\u00C2\u00A0environment\u00C2\u00A0for\u00C2\u00A0 massive\u00C2\u00A0sulphide\u00C2\u00A0mineralization\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0provides\u00C2\u00A0a\u00C2\u00A0unique\u00C2\u00A0perspective\u00C2\u00A0as\u00C2\u00A0many\u00C2\u00A0VMS\u00C2\u00A0 deposits\u00C2\u00A0are\u00C2\u00A0more\u00C2\u00A0deformed\u00C2\u00A0and\u00C2\u00A0more\u00C2\u00A0difficult\u00C2\u00A0to\u00C2\u00A0reconstruct;\u00C2\u00A0(4)\u00C2\u00A0a\u00C2\u00A0synopsis\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0continental\u00E2\u0080\u0090 margin\u00C2\u00A0VMS\u00C2\u00A0setting\u00C2\u00A0with\u00C2\u00A0strong\u00C2\u00A0constraints\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0relationship\u00C2\u00A0to\u00C2\u00A0global\u00C2\u00A0plate\u00C2\u00A0tectonics;\u00C2\u00A0and\u00C2\u00A0(5)\u00C2\u00A0 more\u00C2\u00A0constrained\u00C2\u00A0models\u00C2\u00A0for\u00C2\u00A0VMS\u00C2\u00A0genesis\u00C2\u00A0in\u00C2\u00A0terms\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0relationship\u00C2\u00A0to\u00C2\u00A0associated\u00C2\u00A0felsic\u00C2\u00A0 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study\u00C2\u00A0outlined.\u00C2\u00A0\u00C2\u00A0Geology\u00C2\u00A0modified\u00C2\u00A0after\u00C2\u00A0Jaillard\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1999)\u00C2\u00A0and\u00C2\u00A0Tegart\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(2000).\u00C2\u00A0 Chapter\u00C2\u00A01\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A015\u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A01.2.\u00C2\u00A0\u00C2\u00A0Schematic\u00C2\u00A0model\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0formation\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0(from\u00C2\u00A0Franklin\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02005).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Chapter\u00C2\u00A01\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A016\u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 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Minerals,\u00C2\u00A02002).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Deposit # Drill holes Category1 Metric Tonnes Cu % Zn % Au g/t Ag g/t TG1 sulphide ore 357 Indicated2 56,156,000 1.6 1 0.5 26 Inferred2 3,295,000 1.5 0.8 0.4 18 Probable3 49,200,000 1.6 1 0.4 18 All categories 108,651,000 1.6 1.0 0.5 22 TG1 oxide ore 357 Indicated4 7,964,000 --- --- 3.6 62 Inferred4 725,000 --- --- 3.4 62 Probable5 8,056,000 --- --- 3.5 67 All categories 16,745,000 3.5 64 TG3 sulphide ore 53 Inferred6 82,000,000 1 1.4 0.8 25 B5 sulphide ore 14 ? ? ? ? ? 1\u00C2\u00A0The\u00C2\u00A0reserves\u00C2\u00A0and\u00C2\u00A0resources\u00C2\u00A0are\u00C2\u00A0calculated\u00C2\u00A0in\u00C2\u00A0accordance\u00C2\u00A0with\u00C2\u00A0National\u00C2\u00A0Instrument\u00C2\u00A043\u00E2\u0080\u0090101\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0Standards\u00C2\u00A0of\u00C2\u00A0 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geology\u00C2\u00A0and\u00C2\u00A0ore\u00C2\u00A0deposits\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0central\u00C2\u00A0Andes,\u00C2\u00A0Special\u00C2\u00A0Publication\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0Economic\u00C2\u00A0 Geologists,\u00C2\u00A07:\u00C2\u00A061\u00E2\u0080\u0090107.\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Clark,\u00C2\u00A0A.H.\u00C2\u00A0\u00C2\u00A01993.\u00C2\u00A0\u00C2\u00A0Are\u00C2\u00A0outsize\u00C2\u00A0porphyry\u00C2\u00A0copper\u00C2\u00A0deposits\u00C2\u00A0either\u00C2\u00A0anatomically\u00C2\u00A0or\u00C2\u00A0environmentally\u00C2\u00A0 distinctive?;\u00C2\u00A0giant\u00C2\u00A0ore\u00C2\u00A0deposits.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0Giant\u00C2\u00A0Deposits.\u00C2\u00A0\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0Whiting,\u00C2\u00A0B.H.,\u00C2\u00A0Hodgson,\u00C2\u00A0C.J.,\u00C2\u00A0 and\u00C2\u00A0Mason,\u00C2\u00A0R.\u00C2\u00A0\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0Economic\u00C2\u00A0Geologists,\u00C2\u00A0Special\u00C2\u00A0Publication\u00C2\u00A02,\u00C2\u00A0pp.\u00C2\u00A0213\u00E2\u0080\u0090284.\u00C2\u00A0 \u00C2\u00A0 Clark,\u00C2\u00A0A.H.\u00C2\u00A0\u00C2\u00A01995.\u00C2\u00A0\u00C2\u00A0Proceeding\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Second\u00C2\u00A0Giant\u00C2\u00A0Ore\u00C2\u00A0Deposits\u00C2\u00A0Workshop,\u00C2\u00A0Giant\u00C2\u00A0Ore\u00C2\u00A0Deposits\u00E2\u0080\u0090 II;\u00C2\u00A0Controls\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0scale\u00C2\u00A0of\u00C2\u00A0orogenic\u00C2\u00A0magmatic\u00E2\u0080\u0090hydrothermal\u00C2\u00A0mineralization:\u00C2\u00A0Department\u00C2\u00A0 of\u00C2\u00A0Geological\u00C2\u00A0Sciences,\u00C2\u00A0Queen's\u00C2\u00A0University,\u00C2\u00A0Kingston,\u00C2\u00A0Ontario,\u00C2\u00A0Canada,\u00C2\u00A0753\u00C2\u00A0p.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Converse,\u00C2\u00A0D.R.,\u00C2\u00A0Holland,\u00C2\u00A0H.D.,\u00C2\u00A0and\u00C2\u00A0Edmond,\u00C2\u00A0J.M.\u00C2\u00A0\u00C2\u00A01984.\u00C2\u00A0\u00C2\u00A0Flow\u00C2\u00A0rates\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0axial\u00C2\u00A0hot\u00C2\u00A0springs\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 East\u00C2\u00A0Pacific\u00C2\u00A0Rise\u00C2\u00A0(21oN):\u00C2\u00A0implications\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0heat\u00C2\u00A0budget\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0formation\u00C2\u00A0of\u00C2\u00A0massive\u00C2\u00A0 sulphide\u00C2\u00A0deposits.\u00C2\u00A0\u00C2\u00A0Earth\u00C2\u00A0and\u00C2\u00A0Planetary\u00C2\u00A0Science\u00C2\u00A0Letters,\u00C2\u00A069:\u00C2\u00A0159\u00E2\u0080\u0090175.\u00C2\u00A0 \u00C2\u00A0 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Danielson,\u00C2\u00A0T.,\u00C2\u00A0J.\u00C2\u00A0\u00C2\u00A02000.\u00C2\u00A0\u00C2\u00A0Age,\u00C2\u00A0paleotectonic\u00C2\u00A0setting,\u00C2\u00A0and\u00C2\u00A0common\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0signature\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0San\u00C2\u00A0 Nicol\u00C3\u00A1s\u00C2\u00A0volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposit,\u00C2\u00A0southeastern\u00C2\u00A0Zacatecas\u00C2\u00A0state,\u00C2\u00A0central\u00C2\u00A0 Mexico.\u00C2\u00A0\u00C2\u00A0Unpublished\u00C2\u00A0M.Sc.\u00C2\u00A0thesis,\u00C2\u00A0University\u00C2\u00A0of\u00C2\u00A0British\u00C2\u00A0Columbia,\u00C2\u00A0Vancouver,\u00C2\u00A0B.C.,\u00C2\u00A0 Canada,\u00C2\u00A0120\u00C2\u00A0p.\u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A01\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A022\u00C2\u00A0 Doyle,\u00C2\u00A0M.\u00C2\u00A0G.,\u00C2\u00A0and\u00C2\u00A0Allen,\u00C2\u00A0R.\u00C2\u00A0L.\u00C2\u00A0\u00C2\u00A02003.\u00C2\u00A0\u00C2\u00A0Subseafloor\u00C2\u00A0replacement\u00C2\u00A0in\u00C2\u00A0volcanic\u00E2\u0080\u0090hosted\u00C2\u00A0massive\u00C2\u00A0sulfide\u00C2\u00A0 deposits.\u00C2\u00A0Ore\u00C2\u00A0Geology\u00C2\u00A0Reviews,\u00C2\u00A023:\u00C2\u00A0183\u00E2\u0080\u0090222.\u00C2\u00A0 \u00C2\u00A0 Eastoe,\u00C2\u00A0C.J.\u00C2\u00A0and\u00C2\u00A0Gustin,\u00C2\u00A0M.M.\u00C2\u00A01996.\u00C2\u00A0Volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulfide\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0anoxia\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0 Phanerozoic\u00C2\u00A0oceans,\u00C2\u00A0Ore\u00C2\u00A0Geology\u00C2\u00A0Reviews,\u00C2\u00A010:\u00C2\u00A0179\u00E2\u0080\u0090197.\u00C2\u00A0 \u00C2\u00A0 Feely,\u00C2\u00A0R.A.,\u00C2\u00A0Massoth,\u00C2\u00A0G.J.,\u00C2\u00A0Trefry,\u00C2\u00A0J.H.,\u00C2\u00A0Baker,\u00C2\u00A0E.T.,\u00C2\u00A0Paulson,\u00C2\u00A0A.J.,\u00C2\u00A0and\u00C2\u00A0Lebon,\u00C2\u00A0G.T.\u00C2\u00A0\u00C2\u00A01994.\u00C2\u00A0\u00C2\u00A0 Composition\u00C2\u00A0and\u00C2\u00A0sedimentation\u00C2\u00A0of\u00C2\u00A0hydrothermal\u00C2\u00A0plume\u00C2\u00A0particles\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0North\u00C2\u00A0Cleft\u00C2\u00A0 segment,\u00C2\u00A0Juan\u00C2\u00A0de\u00C2\u00A0Fuca\u00C2\u00A0Ridge.\u00C2\u00A0\u00C2\u00A0Journal\u00C2\u00A0of\u00C2\u00A0Geophysical\u00C2\u00A0Research,\u00C2\u00A099:\u00C2\u00A04985\u00E2\u0080\u00905006.\u00C2\u00A0 \u00C2\u00A0 Franklin,\u00C2\u00A0J.M.,\u00C2\u00A0Sangster,\u00C2\u00A0D.M.,\u00C2\u00A0and\u00C2\u00A0Lydon,\u00C2\u00A0J.W.\u00C2\u00A0\u00C2\u00A01981.\u00C2\u00A0\u00C2\u00A0Volcanic\u00E2\u0080\u0090associated\u00C2\u00A0massive\u00C2\u00A0sulfide\u00C2\u00A0 deposits.\u00C2\u00A0In\u00C2\u00A0Economic\u00C2\u00A0geology;\u00C2\u00A0Seventy\u00E2\u0080\u0090fifth\u00C2\u00A0Anniversary\u00C2\u00A0Volume;\u00C2\u00A01905\u00E2\u0080\u00901980.\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0 B.J.\u00C2\u00A0Skinner.\u00C2\u00A0Economic\u00C2\u00A0Geology\u00C2\u00A0Publishing\u00C2\u00A0Co.,\u00C2\u00A0pp.\u00C2\u00A0485\u00E2\u0080\u0090627.\u00C2\u00A0 \u00C2\u00A0 Franklin,\u00C2\u00A0J.M.,\u00C2\u00A0Gibson,\u00C2\u00A0H.L.,\u00C2\u00A0Jonasson,\u00C2\u00A0I.R.,\u00C2\u00A0and\u00C2\u00A0Galley,\u00C2\u00A0A.G.\u00C2\u00A0\u00C2\u00A02005.\u00C2\u00A0\u00C2\u00A0Volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulfide\u00C2\u00A0 deposits.\u00C2\u00A0In\u00C2\u00A0Economic\u00C2\u00A0Geology;\u00C2\u00A0one\u00C2\u00A0hundredth\u00C2\u00A0anniversary\u00C2\u00A0volume,\u00C2\u00A01905\u00E2\u0080\u00902005.\u00C2\u00A0\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0 J.W.\u00C2\u00A0Hedenquist,\u00C2\u00A0J.F.H.\u00C2\u00A0Thompson,\u00C2\u00A0R.J.\u00C2\u00A0Goldfarb\u00C2\u00A0and\u00C2\u00A0J.P.\u00C2\u00A0Richards.\u00C2\u00A0\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0Economic\u00C2\u00A0 Geologists,\u00C2\u00A0pp.\u00C2\u00A0523\u00E2\u0080\u0090560.\u00C2\u00A0 \u00C2\u00A0 Galley,\u00C2\u00A0A.G.\u00C2\u00A0\u00C2\u00A01993.\u00C2\u00A0\u00C2\u00A0Semi\u00E2\u0080\u0090conformable\u00C2\u00A0alteration\u00C2\u00A0zones\u00C2\u00A0in\u00C2\u00A0volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0 districts.\u00C2\u00A0\u00C2\u00A0Journal\u00C2\u00A0of\u00C2\u00A0Geochemical\u00C2\u00A0Exploration,\u00C2\u00A048:\u00C2\u00A0175\u00E2\u0080\u0090200.\u00C2\u00A0 \u00C2\u00A0 Gibson,\u00C2\u00A0H.L.\u00C2\u00A0and\u00C2\u00A0Watkinson,\u00C2\u00A0D.H.\u00C2\u00A01990.\u00C2\u00A0Volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Noranda\u00C2\u00A0 cauldron\u00C2\u00A0and\u00C2\u00A0shield\u00C2\u00A0volcano,\u00C2\u00A0Quebec;\u00C2\u00A0Special\u00C2\u00A0Volume\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0Canadian\u00C2\u00A0Institute\u00C2\u00A0of\u00C2\u00A0Mining\u00C2\u00A0and\u00C2\u00A0 Metallurgy,\u00C2\u00A043:\u00C2\u00A0119\u00E2\u0080\u0090132.\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Gibson,\u00C2\u00A0H.L.,\u00C2\u00A0Kerr,\u00C2\u00A0D.J.,\u00C2\u00A0and\u00C2\u00A0Cattalani,\u00C2\u00A0S.\u00C2\u00A02000.\u00C2\u00A0The\u00C2\u00A0Horne\u00C2\u00A0Mine;\u00C2\u00A0geology,\u00C2\u00A0history,\u00C2\u00A0influence\u00C2\u00A0on\u00C2\u00A0 genetic\u00C2\u00A0models,\u00C2\u00A0and\u00C2\u00A0a\u00C2\u00A0comparison\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0Kidd\u00C2\u00A0Creek\u00C2\u00A0Mine,\u00C2\u00A0Exploration\u00C2\u00A0and\u00C2\u00A0Mining\u00C2\u00A0 Geology,\u00C2\u00A09:\u00C2\u00A091\u00E2\u0080\u0090111.\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 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Chapter\u00C2\u00A02.\u00C2\u00A0\u00C2\u00A0Volcanic\u00C2\u00A0Stratigraphy\u00C2\u00A0and\u00C2\u00A0Geochronology\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Cretaceous\u00C2\u00A0Lancones\u00C2\u00A0Basin,\u00C2\u00A0 Northwestern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A01\u00C2\u00A0 \u00C2\u00A0 2.1\u00C2\u00A0 Overview\u00C2\u00A0 A\u00C2\u00A0~10\u00C2\u00A0km\u00E2\u0080\u0090thick\u00C2\u00A0sequence\u00C2\u00A0of\u00C2\u00A0Cretaceous\u00C2\u00A0basaltic\u00C2\u00A0to\u00C2\u00A0rhyolitic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0forms\u00C2\u00A0the\u00C2\u00A0arc\u00C2\u00A0 component\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0in\u00C2\u00A0northwestern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0and\u00C2\u00A0underlies\u00C2\u00A0part\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 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and\u00C2\u00A0breccias\u00C2\u00A0with\u00C2\u00A0lesser\u00C2\u00A0aphyric\u00C2\u00A0to\u00C2\u00A0feldspar\u00E2\u0080\u0090quartz\u00C2\u00A0porphyritic\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0 volcanic\u00C2\u00A0successions\u00C2\u00A0filled\u00C2\u00A0the\u00C2\u00A0lowest\u00C2\u00A0exposed\u00C2\u00A0portion\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0basin\u00C2\u00A0and\u00C2\u00A0were\u00C2\u00A0accompanied\u00C2\u00A0by\u00C2\u00A0 volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0(VMS)\u00C2\u00A0deposits,\u00C2\u00A0which\u00C2\u00A0are\u00C2\u00A0inferred\u00C2\u00A0to\u00C2\u00A0have\u00C2\u00A0formed\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0relatively\u00C2\u00A0 deep\u00C2\u00A0marine\u00C2\u00A0setting.\u00C2\u00A0\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0zircon\u00C2\u00A0dating\u00C2\u00A0of\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0at\u00C2\u00A0 Tambogrande\u00C2\u00A0indicate\u00C2\u00A0ages\u00C2\u00A0from\u00C2\u00A0104.8\u00C2\u00A0\u00C2\u00B11.3\u00C2\u00A0to\u00C2\u00A0100.2\u00C2\u00A0\u00C2\u00B10.5\u00C2\u00A0Ma\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0phase\u00C2\u00A01\u00C2\u00A0volcanic\u00C2\u00A0 sequence.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0timing\u00C2\u00A0of\u00C2\u00A0onset\u00C2\u00A0of\u00C2\u00A0rift\u00E2\u0080\u0090related\u00C2\u00A0volcanism\u00C2\u00A0is\u00C2\u00A0not\u00C2\u00A0well\u00C2\u00A0constrained,\u00C2\u00A0but\u00C2\u00A0is\u00C2\u00A0therefore\u00C2\u00A0 of\u00C2\u00A0middle\u00C2\u00A0Albian\u00C2\u00A0age\u00C2\u00A0or\u00C2\u00A0older.\u00C2\u00A0\u00C2\u00A0Phase\u00C2\u00A02\u00C2\u00A0volcanism\u00C2\u00A0is\u00C2\u00A0composed\u00C2\u00A0of\u00C2\u00A0latest\u00C2\u00A0Albian\u00C2\u00A0to\u00C2\u00A0Turonian\u00C2\u00A0 successions\u00C2\u00A0of\u00C2\u00A0relatively\u00C2\u00A0more\u00C2\u00A0felsic\u00E2\u0080\u0090rich\u00C2\u00A0volcaniclastic\u00C2\u00A0rocks\u00C2\u00A0and\u00C2\u00A0yields\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0zircon\u00C2\u00A0ages\u00C2\u00A0of\u00C2\u00A0 99.3\u00C2\u00B10.3\u00C2\u00A0to\u00C2\u00A091.1\u00C2\u00A0\u00C2\u00B11.0\u00C2\u00A0Ma.\u00C2\u00A0\u00C2\u00A0Successions\u00C2\u00A0of\u00C2\u00A0phase\u00C2\u00A02\u00C2\u00A0volcanism\u00C2\u00A0are\u00C2\u00A0intercalated\u00C2\u00A0and\u00C2\u00A0overlain\u00C2\u00A0by\u00C2\u00A0 siliciclastic\u00C2\u00A0and\u00C2\u00A0carbonate\u00C2\u00A0sedimentary\u00C2\u00A0sequences\u00C2\u00A0prevalent\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0western\u00C2\u00A0forearc\u00C2\u00A0section\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0basin.\u00C2\u00A0\u00C2\u00A0Phase\u00C2\u00A02\u00C2\u00A0volcanism\u00C2\u00A0is\u00C2\u00A0followed\u00C2\u00A0by\u00C2\u00A0granitoid\u00C2\u00A0plutonism\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Coastal\u00C2\u00A0Batholith\u00C2\u00A0 beginning\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Late\u00C2\u00A0Cretaceous.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 1 A version of this chapter will be submitted for publication. Winter, L.S., Tosdal, R., and Mortensen, J. Volcanic Stratigraphy and Geochronology of the Cretaceous Lancones Basin, Northwestern Per\u00C3\u00BA. Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A027\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 The\u00C2\u00A0genesis\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Cretaceous\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0and\u00C2\u00A0other\u00C2\u00A0equivalent\u00C2\u00A0rift\u00E2\u0080\u0090related\u00C2\u00A0basins\u00C2\u00A0in\u00C2\u00A0 western\u00C2\u00A0South\u00C2\u00A0America,\u00C2\u00A0including\u00C2\u00A0the\u00C2\u00A0Western\u00C2\u00A0Peruvian\u00C2\u00A0Trough,\u00C2\u00A0is\u00C2\u00A0related\u00C2\u00A0tectonically\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0 break\u00E2\u0080\u0090up\u00C2\u00A0of\u00C2\u00A0Gondwana.\u00C2\u00A0\u00C2\u00A0Phase\u00C2\u00A01\u00C2\u00A0volcanism\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0in\u00C2\u00A0Albian\u00C2\u00A0times\u00C2\u00A0coincided\u00C2\u00A0with\u00C2\u00A0 the\u00C2\u00A0initial\u00C2\u00A0rift\u00C2\u00A0stage,\u00C2\u00A0prior\u00C2\u00A0to\u00C2\u00A0active\u00C2\u00A0oceanic\u00C2\u00A0spreading,\u00C2\u00A0between\u00C2\u00A0South\u00C2\u00A0America\u00C2\u00A0and\u00C2\u00A0Africa.\u00C2\u00A0\u00C2\u00A0 During\u00C2\u00A0this\u00C2\u00A0time\u00C2\u00A0the\u00C2\u00A0relatively\u00C2\u00A0stationary\u00C2\u00A0western\u00C2\u00A0margin\u00C2\u00A0of\u00C2\u00A0continental\u00C2\u00A0South\u00C2\u00A0America\u00C2\u00A0was\u00C2\u00A0 undergoing\u00C2\u00A0extension\u00C2\u00A0and\u00C2\u00A0rifting\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0a\u00C2\u00A0westwards\u00C2\u00A0(oceanwards)\u00C2\u00A0retreating\u00C2\u00A0arc,\u00C2\u00A0resembling\u00C2\u00A0a\u00C2\u00A0 Mariana\u00C2\u00A0arc\u00C2\u00A0type\u00C2\u00A0setting.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0Mochica\u00C2\u00A0orogeny\u00C2\u00A0marks\u00C2\u00A0the\u00C2\u00A0termination\u00C2\u00A0of\u00C2\u00A0rifting,\u00C2\u00A0subsidence\u00C2\u00A0 and\u00C2\u00A0related\u00C2\u00A0volcanism\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0western\u00C2\u00A0margin\u00C2\u00A0of\u00C2\u00A0South\u00C2\u00A0America.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0orogenic\u00C2\u00A0event\u00C2\u00A0also\u00C2\u00A0 broadly\u00C2\u00A0coincides\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0onset\u00C2\u00A0of\u00C2\u00A0spreading\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0South\u00C2\u00A0Atlantic\u00C2\u00A0and\u00C2\u00A0westward\u00C2\u00A0drift\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 South\u00C2\u00A0American\u00C2\u00A0continent.\u00C2\u00A0\u00C2\u00A0Subsequent\u00C2\u00A0phase\u00C2\u00A02\u00C2\u00A0volcanism\u00C2\u00A0was\u00C2\u00A0more\u00C2\u00A0continental\u00C2\u00A0arc\u00E2\u0080\u0090like\u00C2\u00A0under\u00C2\u00A0 an\u00C2\u00A0Andean\u00E2\u0080\u0090type\u00C2\u00A0arc\u00C2\u00A0scenario.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 2.2\u00C2\u00A0 Introduction\u00C2\u00A0 The\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0of\u00C2\u00A0northwestern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0(also\u00C2\u00A0known\u00C2\u00A0as\u00C2\u00A0the\u00C2\u00A0Celica\u00E2\u0080\u0090Lancones\u00C2\u00A0Basin;\u00C2\u00A0Jaillard\u00C2\u00A0 et\u00C2\u00A0al.,\u00C2\u00A01999),\u00C2\u00A0represents\u00C2\u00A0a\u00C2\u00A0Cretaceous\u00C2\u00A0marine\u00C2\u00A0volcanic\u00C2\u00A0and\u00C2\u00A0sedimentary\u00C2\u00A0succession\u00C2\u00A0with\u00C2\u00A0large\u00C2\u00A0 tonnage\u00C2\u00A0deposits\u00C2\u00A0of\u00C2\u00A0base\u00E2\u0080\u0090\u00C2\u00A0and\u00C2\u00A0precious\u00E2\u0080\u0090metal\u00E2\u0080\u0090bearing\u00C2\u00A0massive\u00C2\u00A0sulphides\u00C2\u00A0around\u00C2\u00A0Tambogrande\u00C2\u00A0 (Tegart\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02000;\u00C2\u00A0Chapter\u00C2\u00A03).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0basin\u00C2\u00A0overlaps\u00C2\u00A0both\u00C2\u00A0the\u00C2\u00A0Western\u00C2\u00A0Cordillera\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0Para\u00E2\u0080\u0090 Andean\u00C2\u00A0Depression\u00C2\u00A0of\u00C2\u00A0northwestern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0and\u00C2\u00A0southwestern\u00C2\u00A0Ecuador\u00C2\u00A0(Fig.\u00C2\u00A02.1)\u00C2\u00A0and\u00C2\u00A0represents\u00C2\u00A0 the\u00C2\u00A0northernmost\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0series\u00C2\u00A0of\u00C2\u00A0Late\u00C2\u00A0Jurassic\u00C2\u00A0to\u00C2\u00A0Early\u00C2\u00A0Cretaceous\u00C2\u00A0continental\u00C2\u00A0margin,\u00C2\u00A0arc\u00E2\u0080\u0090related\u00C2\u00A0 rift\u00C2\u00A0basins\u00C2\u00A0extending\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0South\u00C2\u00A0American\u00C2\u00A0western\u00C2\u00A0margin\u00C2\u00A0through\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0(Huarmey\u00C2\u00A0and\u00C2\u00A0 Ca\u00C3\u00B1ete\u00C2\u00A0Basins\u00C2\u00A0or\u00C2\u00A0Western\u00C2\u00A0Peruvian\u00C2\u00A0Trough;\u00C2\u00A0Myers,\u00C2\u00A01974;\u00C2\u00A0Cobbing\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01981;\u00C2\u00A0Atherton\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A0 1983),\u00C2\u00A0Chile\u00C2\u00A0(Coast\u00C2\u00A0Range;\u00C2\u00A0Vergara\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01995),\u00C2\u00A0and\u00C2\u00A0Argentina\u00C2\u00A0(Rocas\u00C2\u00A0Verdes;\u00C2\u00A0Dalziel,\u00C2\u00A01981;\u00C2\u00A0 Hanson\u00C2\u00A0and\u00C2\u00A0Wilson,\u00C2\u00A01991).\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0comparison\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0other\u00C2\u00A0segments\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0marginal\u00C2\u00A0rift\u00C2\u00A0system,\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A028\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0is\u00C2\u00A0well\u00C2\u00A0preserved\u00C2\u00A0and\u00C2\u00A0includes\u00C2\u00A0the\u00C2\u00A0arc\u00C2\u00A0and\u00C2\u00A0forearc\u00C2\u00A0components\u00C2\u00A0as\u00C2\u00A0well\u00C2\u00A0as\u00C2\u00A0 accreted\u00C2\u00A0allochthonous\u00C2\u00A0crustal\u00C2\u00A0blocks\u00C2\u00A0(i.e.,\u00C2\u00A0the\u00C2\u00A0Amotape\u00C2\u00A0terrain;\u00C2\u00A0Fig.\u00C2\u00A02.2).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 In\u00C2\u00A0this\u00C2\u00A0chapter\u00C2\u00A0the\u00C2\u00A0geology\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin,\u00C2\u00A0with\u00C2\u00A0emphasis\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0 successions\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0eastern\u00C2\u00A0portion\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0basin,\u00C2\u00A0are\u00C2\u00A0reviewed\u00C2\u00A0based\u00C2\u00A0on\u00C2\u00A0recent\u00C2\u00A0mapping\u00C2\u00A0and\u00C2\u00A0 examination\u00C2\u00A0of\u00C2\u00A0diamond\u00C2\u00A0drill\u00C2\u00A0core.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0documentation\u00C2\u00A0represents\u00C2\u00A0a\u00C2\u00A0detailed\u00C2\u00A0account\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 volcanic\u00C2\u00A0successions\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0and\u00C2\u00A0places\u00C2\u00A0the\u00C2\u00A0Tambogrande\u00C2\u00A0volcanogenic\u00C2\u00A0massive\u00C2\u00A0 sulphide\u00C2\u00A0(VMS)\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0stratigraphic\u00C2\u00A0context.\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0represent\u00C2\u00A0the\u00C2\u00A0largest\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0and\u00C2\u00A0represent\u00C2\u00A0the\u00C2\u00A0most\u00C2\u00A0significant\u00C2\u00A0group\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0 in\u00C2\u00A0South\u00C2\u00A0America,\u00C2\u00A0each\u00C2\u00A0with\u00C2\u00A0a\u00C2\u00A0gross\u00C2\u00A0tonnage\u00C2\u00A0of\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0of\u00C2\u00A0~100\u00C2\u00A0Mt.\u00C2\u00A0\u00C2\u00A0Furthermore,\u00C2\u00A0 they\u00C2\u00A0are\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0upper\u00C2\u00A03%\u00C2\u00A0of\u00C2\u00A0all\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0of\u00C2\u00A0their\u00C2\u00A0type\u00C2\u00A0globally\u00C2\u00A0with\u00C2\u00A0respect\u00C2\u00A0to\u00C2\u00A0size\u00C2\u00A0 (Franklin\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02005).\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0addition,\u00C2\u00A0the\u00C2\u00A0first\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0zircon\u00C2\u00A0ages\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0 Lancones\u00C2\u00A0marginal\u00C2\u00A0basin\u00C2\u00A0of\u00C2\u00A0northwestern\u00C2\u00A0coastal\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0are\u00C2\u00A0presented\u00C2\u00A0herein.\u00C2\u00A0\u00C2\u00A0 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trending\u00C2\u00A0dextral\u00C2\u00A0faults\u00C2\u00A0developed\u00C2\u00A0during\u00C2\u00A0clockwise\u00C2\u00A0rotation\u00C2\u00A0(Mourier\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01988;\u00C2\u00A0Fig.\u00C2\u00A02.3B).\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0accretion\u00C2\u00A0is\u00C2\u00A0temporally\u00C2\u00A0linked\u00C2\u00A0to,\u00C2\u00A0and\u00C2\u00A0likely\u00C2\u00A0triggered,\u00C2\u00A0the\u00C2\u00A0westward\u00C2\u00A0relocation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0plate\u00C2\u00A0 boundary\u00C2\u00A0which\u00C2\u00A0manifested\u00C2\u00A0as\u00C2\u00A0a\u00C2\u00A0new\u00C2\u00A0subduction\u00C2\u00A0zone\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0north\u00E2\u0080\u0090northwest\u00E2\u0080\u0090trending\u00C2\u00A0 Peruvian\u00C2\u00A0segment.\u00C2\u00A0\u00C2\u00A0Under\u00C2\u00A0this\u00C2\u00A0Mariana\u00E2\u0080\u0090type\u00C2\u00A0arc\u00C2\u00A0system,\u00C2\u00A0steep\u00C2\u00A0subduction\u00C2\u00A0and\u00C2\u00A0slab\u00C2\u00A0roll\u00E2\u0080\u0090back\u00C2\u00A0 caused\u00C2\u00A0extension\u00C2\u00A0and\u00C2\u00A0attenuation\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0overriding\u00C2\u00A0continental\u00C2\u00A0plate\u00C2\u00A0and\u00C2\u00A0resulted\u00C2\u00A0in\u00C2\u00A0rifting\u00C2\u00A0and\u00C2\u00A0 the\u00C2\u00A0formation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin,\u00C2\u00A0followed\u00C2\u00A0by\u00C2\u00A0the\u00C2\u00A0deposition\u00C2\u00A0of\u00C2\u00A0marine\u00C2\u00A0sequences\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A030\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 eruption\u00C2\u00A0of\u00C2\u00A0large\u00C2\u00A0volumes\u00C2\u00A0of\u00C2\u00A0mafic\u00E2\u0080\u0090dominated\u00C2\u00A0arc\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0(Fig.\u00C2\u00A02.3C;\u00C2\u00A0Benavides\u00E2\u0080\u0090C\u00C3\u00A1ceres,\u00C2\u00A0 1999).\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0clockwise\u00C2\u00A0rotation\u00C2\u00A0may\u00C2\u00A0have\u00C2\u00A0been\u00C2\u00A0related\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0opening\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0in\u00C2\u00A0 Albian\u00C2\u00A0times\u00C2\u00A0(Winter\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02002).\u00C2\u00A0\u00C2\u00A0Gravity\u00C2\u00A0modeling\u00C2\u00A0of\u00C2\u00A0crustal\u00C2\u00A0structure\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0Peruvian\u00C2\u00A0 continental\u00C2\u00A0margin\u00C2\u00A0indicates\u00C2\u00A0that\u00C2\u00A0a\u00C2\u00A0dense\u00C2\u00A0arch\u00E2\u0080\u0090like\u00C2\u00A0structure\u00C2\u00A0of\u00C2\u00A03.0\u00C2\u00A0g/cm3\u00C2\u00A0underlies\u00C2\u00A0the\u00C2\u00A0 volcanic\u00E2\u0080\u0090dominated\u00C2\u00A0portion\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Western\u00C2\u00A0Peruvian\u00C2\u00A0Trough\u00C2\u00A0and\u00C2\u00A0possibly\u00C2\u00A0represents\u00C2\u00A0the\u00C2\u00A0 intrusion\u00C2\u00A0of\u00C2\u00A0basic\u00C2\u00A0material\u00C2\u00A0into\u00C2\u00A0the\u00C2\u00A0continental\u00C2\u00A0crust\u00C2\u00A0(Jones,\u00C2\u00A01981).\u00C2\u00A0 \u00C2\u00A0In\u00C2\u00A0late\u00C2\u00A0Albian\u00C2\u00A0times\u00C2\u00A0the\u00C2\u00A0geodynamical\u00C2\u00A0cycle\u00C2\u00A0shifted\u00C2\u00A0towards\u00C2\u00A0Andean\u00E2\u0080\u0090type\u00C2\u00A0subduction\u00C2\u00A0and\u00C2\u00A0 marked\u00C2\u00A0the\u00C2\u00A0first\u00C2\u00A0Andean\u00C2\u00A0compressive\u00C2\u00A0tectonism,\u00C2\u00A0i.e.,\u00C2\u00A0Mochica\u00C2\u00A0Phase\u00C2\u00A0(M\u00C3\u00A9gard,\u00C2\u00A01984)\u00C2\u00A0and\u00C2\u00A0 subsequent\u00C2\u00A0continental\u00C2\u00A0arc\u00C2\u00A0volcanism\u00C2\u00A0and\u00C2\u00A0plutonism\u00C2\u00A0(Coastal\u00C2\u00A0Batholith).\u00C2\u00A0\u00C2\u00A0An\u00C2\u00A0increasing\u00C2\u00A0 convergence\u00C2\u00A0rate\u00C2\u00A0through\u00C2\u00A0the\u00C2\u00A0Albian\u00C2\u00A0(Soler\u00C2\u00A0and\u00C2\u00A0Bonhomme,\u00C2\u00A01990),\u00C2\u00A0temporally\u00C2\u00A0linked\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0 opening\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0South\u00C2\u00A0Atlantic,\u00C2\u00A0may\u00C2\u00A0have\u00C2\u00A0been\u00C2\u00A0responsible\u00C2\u00A0for\u00C2\u00A0this\u00C2\u00A0transition\u00C2\u00A0in\u00C2\u00A0subduction\u00C2\u00A0zone\u00C2\u00A0 setting.\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0series\u00C2\u00A0of\u00C2\u00A0post\u00E2\u0080\u0090rift\u00C2\u00A0collisional\u00C2\u00A0events\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0Northern\u00C2\u00A0Andes\u00C2\u00A0in\u00C2\u00A0Ecuador\u00C2\u00A0shortened\u00C2\u00A0 the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0and\u00C2\u00A0contributed\u00C2\u00A0an\u00C2\u00A0additional\u00C2\u00A0component\u00C2\u00A0of\u00C2\u00A0clockwise\u00C2\u00A0rotation\u00C2\u00A0(Mitouard\u00C2\u00A0 et\u00C2\u00A0al.,\u00C2\u00A01990).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0accretion\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Pallatanga\u00C2\u00A0Terrane\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Late\u00C2\u00A0Cretaceous\u00C2\u00A0to\u00C2\u00A0Paleocene\u00C2\u00A0(Fig.\u00C2\u00A0 2.3D)\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0Macuchi\u00C2\u00A0Island\u00C2\u00A0Arc\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0late\u00C2\u00A0Eocene\u00C2\u00A0to\u00C2\u00A0early\u00C2\u00A0Oligocene\u00C2\u00A0(Huges\u00C2\u00A0and\u00C2\u00A0Pilatasig,\u00C2\u00A0 2002;\u00C2\u00A0Spikings\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02005)\u00C2\u00A0led\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0current\u00C2\u00A0terrain\u00C2\u00A0configuration\u00C2\u00A0(Fig.\u00C2\u00A02.3E).\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0compressive\u00C2\u00A0 tectonic\u00C2\u00A0regime\u00C2\u00A0continues\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0present\u00C2\u00A0day.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 2.4\u00C2\u00A0 Regional\u00C2\u00A0Geology\u00C2\u00A0 The\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0is\u00C2\u00A0situated\u00C2\u00A0at\u00C2\u00A0a\u00C2\u00A0major\u00C2\u00A0oroclinal\u00C2\u00A0bend\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Andes,\u00C2\u00A0the\u00C2\u00A0Huancabamba\u00C2\u00A0 deflection,\u00C2\u00A0which\u00C2\u00A0separates\u00C2\u00A0the\u00C2\u00A0north\u00E2\u0080\u0090northwest\u00E2\u0080\u0090trending\u00C2\u00A0Peruvian\u00C2\u00A0Andes\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0northeast\u00E2\u0080\u0090 trending\u00C2\u00A0Ecuadorian\u00C2\u00A0Andes\u00C2\u00A0(Mitouard\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01990;\u00C2\u00A0Fig.\u00C2\u00A02.2).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0basin\u00C2\u00A0is\u00C2\u00A0limited\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0east\u00E2\u0080\u0090 southeast\u00C2\u00A0and\u00C2\u00A0southwest\u00C2\u00A0to\u00C2\u00A0north\u00C2\u00A0by\u00C2\u00A0continental\u00C2\u00A0crustal\u00C2\u00A0blocks\u00C2\u00A0that\u00C2\u00A0represent\u00C2\u00A0the\u00C2\u00A0Jurassic\u00C2\u00A0to\u00C2\u00A0 Early\u00C2\u00A0Cretaceous\u00C2\u00A0pre\u00E2\u0080\u0090rift\u00C2\u00A0Andean\u00C2\u00A0margin\u00C2\u00A0and\u00C2\u00A0were\u00C2\u00A0topographical\u00C2\u00A0highs\u00C2\u00A0during\u00C2\u00A0deposition\u00C2\u00A0in\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A031\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Mesozoic\u00C2\u00A0times\u00C2\u00A0(Cobbing\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01981).\u00C2\u00A0\u00C2\u00A0To\u00C2\u00A0the\u00C2\u00A0southeast,\u00C2\u00A0the\u00C2\u00A0Paleozoic(?)\u00C2\u00A0Olmos\u00C2\u00A0Massif\u00C2\u00A0is\u00C2\u00A0a\u00C2\u00A0 probable\u00C2\u00A0reactivated\u00C2\u00A0margin\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Amazonian\u00C2\u00A0craton\u00C2\u00A0(Macfarlane,\u00C2\u00A01999).\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0poorly\u00C2\u00A0defined\u00C2\u00A0 terrain\u00C2\u00A0consists\u00C2\u00A0of\u00C2\u00A0pre\u00E2\u0080\u0090Ordovician\u00C2\u00A0greenschist\u00C2\u00A0facies\u00C2\u00A0pelitic\u00C2\u00A0to\u00C2\u00A0psammitic\u00C2\u00A0rocks\u00C2\u00A0overlain\u00C2\u00A0by\u00C2\u00A0 platform\u00C2\u00A0carbonate\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0Triassic\u00C2\u00A0to\u00C2\u00A0Early\u00C2\u00A0Jurassic\u00C2\u00A0age,\u00C2\u00A0considered\u00C2\u00A0equivalent\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0Mara\u00C3\u00B1on\u00C2\u00A0 Geanticline\u00C2\u00A0farther\u00C2\u00A0southeast\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0(Cobbing\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01981;\u00C2\u00A0Reyes\u00C2\u00A0and\u00C2\u00A0Caldas,\u00C2\u00A01987;\u00C2\u00A0 Mourier\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01988;\u00C2\u00A0Litherland\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01994).\u00C2\u00A0\u00C2\u00A0Bordering\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0southwest,\u00C2\u00A0 west\u00C2\u00A0and\u00C2\u00A0north,\u00C2\u00A0are\u00C2\u00A0Paleozoic\u00C2\u00A0or\u00C2\u00A0older\u00C2\u00A0meta\u00E2\u0080\u0090sedimentary\u00C2\u00A0rocks\u00C2\u00A0and\u00C2\u00A0Triassic\u00C2\u00A0granitic\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 Amotape\u00C2\u00A0Range\u00C2\u00A0(Mourier\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01988;\u00C2\u00A0Aspden\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01995;\u00C2\u00A0Noble\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01997;\u00C2\u00A0Appendix\u00C2\u00A0B).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Volcanic\u00C2\u00A0and\u00C2\u00A0sedimentary\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Cretaceous\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0can\u00C2\u00A0be\u00C2\u00A0subdivided\u00C2\u00A0into\u00C2\u00A0an\u00C2\u00A0 eastern\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0and\u00C2\u00A0western\u00C2\u00A0forearc.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0rocks\u00C2\u00A0are\u00C2\u00A0exposed\u00C2\u00A0over\u00C2\u00A0135\u00C2\u00A0kilometres\u00C2\u00A0in\u00C2\u00A0strike\u00C2\u00A0 and\u00C2\u00A0~150\u00C2\u00A0kilometres\u00C2\u00A0width\u00C2\u00A0through\u00C2\u00A0northwestern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0and\u00C2\u00A0southwestern\u00C2\u00A0Ecuador.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0basin\u00C2\u00A0 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which\u00C2\u00A0dominate\u00C2\u00A0the\u00C2\u00A0western\u00C2\u00A0forearc\u00C2\u00A0portion\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0(Jaillard\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01999).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0 forearc\u00C2\u00A0turbiditic\u00C2\u00A0subbasin\u00C2\u00A0was\u00C2\u00A0filled\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A03\u00C2\u00A0km\u00C2\u00A0thick\u00C2\u00A0Copa\u00C2\u00A0Sombrero\u00C2\u00A0Group\u00C2\u00A0that\u00C2\u00A0interfingers\u00C2\u00A0 at\u00C2\u00A0the\u00C2\u00A0base\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0group\u00C2\u00A0but,\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0most\u00C2\u00A0part,\u00C2\u00A0overlap\u00C2\u00A0and\u00C2\u00A0buried\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0sequence\u00C2\u00A0 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not\u00C2\u00A0been\u00C2\u00A0seen\u00C2\u00A0in\u00C2\u00A0outcrop\u00C2\u00A0or\u00C2\u00A0drill\u00C2\u00A0core\u00C2\u00A0but\u00C2\u00A0siliciclastic\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0San\u00C2\u00A0Pedro\u00C2\u00A0Group\u00C2\u00A0present\u00C2\u00A0to\u00C2\u00A0 the\u00C2\u00A0east\u00C2\u00A0are\u00C2\u00A0interpreted\u00C2\u00A0as\u00C2\u00A0the\u00C2\u00A0earliest\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Cretaceous\u00C2\u00A0sequences\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0basin\u00C2\u00A0(Reyes\u00C2\u00A0and\u00C2\u00A0 Caldas,\u00C2\u00A01987).\u00C2\u00A0\u00C2\u00A0Geochronological\u00C2\u00A0data\u00C2\u00A0presented\u00C2\u00A0herein\u00C2\u00A0limit\u00C2\u00A0phase\u00C2\u00A01\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0late\u00C2\u00A0 Albian.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0phase\u00C2\u00A01\u00C2\u00A0volcanic\u00C2\u00A0sequence\u00C2\u00A0is\u00C2\u00A0of\u00C2\u00A0economic\u00C2\u00A0interest\u00C2\u00A0as\u00C2\u00A0it\u00C2\u00A0hosts\u00C2\u00A0all\u00C2\u00A0known\u00C2\u00A0VMS\u00C2\u00A0 deposits\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0phase\u00C2\u00A02\u00C2\u00A0volcanic\u00C2\u00A0cycle\u00C2\u00A0is\u00C2\u00A0defined\u00C2\u00A0as\u00C2\u00A0an\u00C2\u00A08\u00C2\u00A0km\u00E2\u0080\u0090thick\u00C2\u00A0sequence\u00C2\u00A0of\u00C2\u00A0mafic\u00C2\u00A0to\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0 and\u00C2\u00A0volcaniclastic\u00C2\u00A0rocks\u00C2\u00A0with\u00C2\u00A0subordinate\u00C2\u00A0sedimentary\u00C2\u00A0rocks\u00C2\u00A0that\u00C2\u00A0represent\u00C2\u00A0a\u00C2\u00A0more\u00C2\u00A0shallow\u00C2\u00A0 water\u00C2\u00A0setting.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0upper\u00C2\u00A0part\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0phase\u00C2\u00A02\u00C2\u00A0volcanic\u00C2\u00A0cycle,\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Formation,\u00C2\u00A0is\u00C2\u00A0 dominated\u00C2\u00A0by\u00C2\u00A0volcaniclastic\u00C2\u00A0rocks\u00C2\u00A0and\u00C2\u00A0intercalated\u00C2\u00A0with\u00C2\u00A0sedimentary\u00C2\u00A0and\u00C2\u00A0notably\u00C2\u00A0calcareous\u00C2\u00A0 rocks\u00C2\u00A0that\u00C2\u00A0mark\u00C2\u00A0a\u00C2\u00A0transition\u00C2\u00A0to\u00C2\u00A0forearc\u00C2\u00A0turbidite\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Copa\u00C2\u00A0Sombrero\u00C2\u00A0Group.\u00C2\u00A0\u00C2\u00A0Rocks\u00C2\u00A0within\u00C2\u00A0 phase\u00C2\u00A02\u00C2\u00A0are\u00C2\u00A0late\u00C2\u00A0Albian\u00C2\u00A0to\u00C2\u00A0Turonian(?)\u00C2\u00A0based\u00C2\u00A0on\u00C2\u00A0geochronological\u00C2\u00A0data\u00C2\u00A0presented\u00C2\u00A0in\u00C2\u00A0this\u00C2\u00A0 chapter.\u00C2\u00A0 \u00C2\u00A0Metamorphic\u00C2\u00A0grades\u00C2\u00A0range\u00C2\u00A0from\u00C2\u00A0zeolite\u00C2\u00A0to\u00C2\u00A0lower\u00C2\u00A0greenschist\u00C2\u00A0facies,\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0higher\u00C2\u00A0 metamorphic\u00C2\u00A0grade\u00C2\u00A0mineral\u00C2\u00A0assemblages\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0thermal\u00C2\u00A0metamorphism\u00C2\u00A0around\u00C2\u00A0younger\u00C2\u00A0 plutonic\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0Diagenesis\u00C2\u00A0and\u00C2\u00A0seafloor\u00C2\u00A0metasomatism,due\u00C2\u00A0to\u00C2\u00A0seawater\u00E2\u0080\u0090rock\u00C2\u00A0interaction,\u00C2\u00A0 resulted\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0wide\u00C2\u00A0range\u00C2\u00A0of\u00C2\u00A0low\u00E2\u0080\u0090temperature\u00C2\u00A0replacement\u00C2\u00A0and\u00C2\u00A0open\u00E2\u0080\u0090space\u00E2\u0080\u0090filling\u00C2\u00A0minerals\u00C2\u00A0 within\u00C2\u00A0basaltic\u00C2\u00A0rocks,\u00C2\u00A0including\u00C2\u00A0analcite,\u00C2\u00A0albite\u00C2\u00A0(after\u00C2\u00A0plagioclase),\u00C2\u00A0amphibole\u00C2\u00A0(uralitized\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A034\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 clinopyroxene),\u00C2\u00A0carbonate\u00C2\u00A0minerals,\u00C2\u00A0chlorite,\u00C2\u00A0epidote,\u00C2\u00A0hematite,\u00C2\u00A0palagonite\u00C2\u00A0(after\u00C2\u00A0groundmass\u00C2\u00A0 glass),\u00C2\u00A0prehnite,\u00C2\u00A0pumpellyite,\u00C2\u00A0sericite\u00C2\u00A0or\u00C2\u00A0various\u00C2\u00A0clays\u00C2\u00A0(sausseritized\u00C2\u00A0feldspar),\u00C2\u00A0and\u00C2\u00A0zeolites.\u00C2\u00A0\u00C2\u00A0 Hydrothermal\u00C2\u00A0alteration\u00C2\u00A0is\u00C2\u00A0confined\u00C2\u00A0to\u00C2\u00A0discordant\u00C2\u00A0zones\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0footwall\u00C2\u00A0rocks\u00C2\u00A0immediately\u00C2\u00A0 below\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0includes\u00C2\u00A0variable\u00C2\u00A0replacement\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0rocks\u00C2\u00A0with\u00C2\u00A0Fe\u00E2\u0080\u0090 chlorite,\u00C2\u00A0sericite\u00C2\u00A0and\u00C2\u00A0quartz\u00C2\u00A0in\u00C2\u00A0addition\u00C2\u00A0to\u00C2\u00A0stringer\u00C2\u00A0and\u00C2\u00A0disseminated\u00C2\u00A0sulphide\u00C2\u00A0mineralization\u00C2\u00A0 (Tegart\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02000).\u00C2\u00A0\u00C2\u00A0None\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0this\u00C2\u00A0study\u00C2\u00A0show\u00C2\u00A0the\u00C2\u00A0effects\u00C2\u00A0of\u00C2\u00A0significant\u00C2\u00A0ductile\u00C2\u00A0strain\u00C2\u00A0 and\u00C2\u00A0primary\u00C2\u00A0textures\u00C2\u00A0are\u00C2\u00A0generally\u00C2\u00A0well\u00C2\u00A0preserved.\u00C2\u00A0 2.5.1\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0 The\u00C2\u00A0lowermost\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0sequences,\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0(Fig.\u00C2\u00A02.6),\u00C2\u00A0is\u00C2\u00A0 characterized\u00C2\u00A0by\u00C2\u00A0bimodal\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0dominated\u00C2\u00A0by\u00C2\u00A0pillow\u00C2\u00A0basalt.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0depositional\u00C2\u00A0 environment\u00C2\u00A0is\u00C2\u00A0considered\u00C2\u00A0to\u00C2\u00A0have\u00C2\u00A0been\u00C2\u00A0relatively\u00C2\u00A0deep\u00C2\u00A0marine,\u00C2\u00A0based\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0absence\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 pyroclastic\u00C2\u00A0rocks\u00C2\u00A0and\u00C2\u00A0with\u00C2\u00A0sedimentary\u00C2\u00A0rocks\u00C2\u00A0limited\u00C2\u00A0to\u00C2\u00A0thin\u00C2\u00A0units\u00C2\u00A0of\u00C2\u00A0laminated\u00C2\u00A0black\u00C2\u00A0mudstone.\u00C2\u00A0\u00C2\u00A0 Felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0represent\u00C2\u00A0approximately\u00C2\u00A010%\u00C2\u00A0or\u00C2\u00A0less\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0total\u00C2\u00A0volume\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0formation.\u00C2\u00A0\u00C2\u00A0 Drill\u00C2\u00A0holes\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0south\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0basin\u00C2\u00A0near\u00C2\u00A0the\u00C2\u00A0vicinity\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0tested\u00C2\u00A0to\u00C2\u00A0a\u00C2\u00A0 maximum\u00C2\u00A0depth\u00C2\u00A0of\u00C2\u00A0~800\u00C2\u00A0m\u00C2\u00A0and\u00C2\u00A0did\u00C2\u00A0not\u00C2\u00A0intersect\u00C2\u00A0a\u00C2\u00A0basal\u00C2\u00A0contact\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 Formation.\u00C2\u00A0\u00C2\u00A0Simplified\u00C2\u00A0geological\u00C2\u00A0sections,\u00C2\u00A0interpreted\u00C2\u00A0from\u00C2\u00A0data\u00C2\u00A0generated\u00C2\u00A0through\u00C2\u00A0field\u00C2\u00A0 mapping\u00C2\u00A0as\u00C2\u00A0well\u00C2\u00A0as\u00C2\u00A0drill\u00C2\u00A0core\u00C2\u00A0(Fig.\u00C2\u00A02.5),\u00C2\u00A0suggest\u00C2\u00A0a\u00C2\u00A0possible\u00C2\u00A0thickness\u00C2\u00A0of\u00C2\u00A0up\u00C2\u00A0to\u00C2\u00A02,500\u00C2\u00A0m.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Basalt\u00C2\u00A0is\u00C2\u00A0variably\u00C2\u00A0feldspar\u00E2\u0080\u0090\u00C2\u00A0(0\u00E2\u0080\u009020%)\u00C2\u00A0and\u00C2\u00A0augite\u00E2\u0080\u0090\u00C2\u00A0(0\u00E2\u0080\u00905%)\u00C2\u00A0porphyritic\u00C2\u00A0or\u00C2\u00A0microporphyritic,\u00C2\u00A0and\u00C2\u00A0is\u00C2\u00A0 typically\u00C2\u00A0vesicular\u00C2\u00A0with\u00C2\u00A02\u00E2\u0080\u009010%,\u00C2\u00A01\u00E2\u0080\u00905\u00C2\u00A0mm\u00C2\u00A0amygdules\u00C2\u00A0(Fig.\u00C2\u00A02.7A).\u00C2\u00A0\u00C2\u00A0Near\u00C2\u00A0the\u00C2\u00A0B5\u00C2\u00A0deposit\u00C2\u00A0(Fig.\u00C2\u00A02.1),\u00C2\u00A0 basalt\u00C2\u00A0is\u00C2\u00A0locally\u00C2\u00A0scoria\u00E2\u0080\u0090like\u00C2\u00A0and\u00C2\u00A0includes\u00C2\u00A0breccia\u00C2\u00A0with\u00C2\u00A0mm\u00E2\u0080\u0090scale\u00C2\u00A0clasts\u00C2\u00A0dominated\u00C2\u00A0by\u00C2\u00A0bubble\u00C2\u00A0wall\u00C2\u00A0 shards\u00C2\u00A0(Fig.\u00C2\u00A02.7B,\u00C2\u00A0C).\u00C2\u00A0\u00C2\u00A0Massive\u00C2\u00A0to\u00C2\u00A0pillowed\u00C2\u00A0flows\u00C2\u00A0are\u00C2\u00A0the\u00C2\u00A0most\u00C2\u00A0common\u00C2\u00A0lithofacies\u00C2\u00A0and\u00C2\u00A0form\u00C2\u00A0 monotonous\u00C2\u00A0nondescript\u00C2\u00A0intervals\u00C2\u00A0up\u00C2\u00A0to\u00C2\u00A0several\u00C2\u00A0hundred\u00C2\u00A0metres\u00C2\u00A0thick.\u00C2\u00A0\u00C2\u00A0Pillows\u00C2\u00A0are\u00C2\u00A0typically\u00C2\u00A00.5\u00E2\u0080\u0090 1.0\u00C2\u00A0m\u00C2\u00A0in\u00C2\u00A0diameter\u00C2\u00A0(Fig.\u00C2\u00A02.7D),\u00C2\u00A0commonly\u00C2\u00A0with\u00C2\u00A0radial\u00C2\u00A0fractures\u00C2\u00A0and\u00C2\u00A0\u00E2\u0080\u0098onion\u00E2\u0080\u0090skin\u00E2\u0080\u0099\u00E2\u0080\u0090type\u00C2\u00A0concentric\u00C2\u00A0 flow\u00C2\u00A0foliations\u00C2\u00A0(Fig.\u00C2\u00A02.7E).\u00C2\u00A0\u00C2\u00A0Individual\u00C2\u00A0pillow\u00C2\u00A0lava\u00C2\u00A0flow\u00C2\u00A0units\u00C2\u00A0are\u00C2\u00A0decametres\u00C2\u00A0thick\u00C2\u00A0and\u00C2\u00A0associated\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A035\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 with\u00C2\u00A0a\u00C2\u00A0variety\u00C2\u00A0of\u00C2\u00A0breccia\u00C2\u00A0types\u00C2\u00A0(Fig.\u00C2\u00A02.7F).\u00C2\u00A0\u00C2\u00A0Pillow\u00C2\u00A0fragment\u00C2\u00A0breccia\u00C2\u00A0is\u00C2\u00A0derived\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0collapse\u00C2\u00A0 of\u00C2\u00A0pillow\u00C2\u00A0mounds\u00C2\u00A0that\u00C2\u00A0vary\u00C2\u00A0from\u00C2\u00A0proximal\u00C2\u00A0talus\u00C2\u00A0breccia\u00C2\u00A0to\u00C2\u00A0distal\u00C2\u00A0facies\u00C2\u00A0showing\u00C2\u00A0evidence\u00C2\u00A0of\u00C2\u00A0 mass\u00C2\u00A0transport,\u00C2\u00A0e.g.,\u00C2\u00A0reverse\u00C2\u00A0sorting\u00C2\u00A0(Fig.\u00C2\u00A02.7G).\u00C2\u00A0\u00C2\u00A0Basaltic\u00C2\u00A0autoclastic\u00C2\u00A0breccia\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0 San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0includes\u00C2\u00A0hyaloclastite\u00C2\u00A0and\u00C2\u00A0autobreccia.\u00C2\u00A0\u00C2\u00A0Hyaloclastite\u00C2\u00A0has\u00C2\u00A0angular\u00C2\u00A0and\u00C2\u00A0 cuspate,\u00C2\u00A0mostly\u00C2\u00A0pebble\u00E2\u0080\u0090size\u00C2\u00A0breccia\u00C2\u00A0clasts\u00C2\u00A0with\u00C2\u00A0distinct\u00C2\u00A0clast\u00C2\u00A0outlines\u00C2\u00A0and\u00C2\u00A0often\u00C2\u00A0jigsaw\u00E2\u0080\u0090fit\u00C2\u00A0 textures\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0quench\u00C2\u00A0fragmentation\u00C2\u00A0in\u00C2\u00A0seawater\u00C2\u00A0(Fig.\u00C2\u00A02.7H).\u00C2\u00A0\u00C2\u00A0Autobreccia,\u00C2\u00A0formed\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0 viscosity\u00C2\u00A0variations\u00C2\u00A0within\u00C2\u00A0a\u00C2\u00A0cooling\u00C2\u00A0and\u00C2\u00A0flowing\u00C2\u00A0lava,\u00C2\u00A0display\u00C2\u00A0amoeboid\u00E2\u0080\u0090shaped\u00C2\u00A0clasts\u00C2\u00A0with\u00C2\u00A0 abundant,\u00C2\u00A0fine\u00C2\u00A0(<\u00C2\u00A01\u00C2\u00A0mm)\u00C2\u00A0amygdules\u00C2\u00A0(Fig.\u00C2\u00A02.7I).\u00C2\u00A0\u00C2\u00A0Autobreccia\u00C2\u00A0clasts\u00C2\u00A0are\u00C2\u00A0typically\u00C2\u00A0maroon\u00C2\u00A0colour\u00C2\u00A0 due\u00C2\u00A0to\u00C2\u00A0hematization\u00C2\u00A0and\u00C2\u00A0have\u00C2\u00A0diffuse\u00C2\u00A0clast\u00C2\u00A0margins\u00C2\u00A0that\u00C2\u00A0grade\u00C2\u00A0into\u00C2\u00A0a\u00C2\u00A0darker,\u00C2\u00A0chloritic\u00C2\u00A0matrix.\u00C2\u00A0\u00C2\u00A0 Volcanic\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0host\u00C2\u00A0all\u00C2\u00A0known\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0 prospects\u00C2\u00A0(TG1,\u00C2\u00A0TG3,\u00C2\u00A0and\u00C2\u00A0B5).\u00C2\u00A0\u00C2\u00A0Though\u00C2\u00A0outcrop\u00C2\u00A0is\u00C2\u00A0poor\u00C2\u00A0to\u00C2\u00A0non\u00E2\u0080\u0090existent\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0vicinity\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 deposits,\u00C2\u00A0an\u00C2\u00A0extensive\u00C2\u00A0drill\u00C2\u00A0core\u00C2\u00A0library\u00C2\u00A0was\u00C2\u00A0available\u00C2\u00A0for\u00C2\u00A0study.\u00C2\u00A0\u00C2\u00A0Construction\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0rhyolite\u00E2\u0080\u0090dacite\u00C2\u00A0 volcanic\u00C2\u00A0complex\u00C2\u00A0intimately\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0is\u00C2\u00A0documented\u00C2\u00A0by\u00C2\u00A0Winter\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0 (2004).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0extent\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0felsic\u00C2\u00A0complex\u00C2\u00A0is\u00C2\u00A0not\u00C2\u00A0completely\u00C2\u00A0delimited,\u00C2\u00A0but\u00C2\u00A0at\u00C2\u00A0TG1\u00C2\u00A0and\u00C2\u00A0TG3\u00C2\u00A0it\u00C2\u00A0is\u00C2\u00A0a\u00C2\u00A0 minimum\u00C2\u00A0of\u00C2\u00A02\u00C2\u00A0km\u00C2\u00A0in\u00C2\u00A0diameter\u00C2\u00A0and\u00C2\u00A0with\u00C2\u00A0a\u00C2\u00A0composite\u00C2\u00A0thickness\u00C2\u00A0of\u00C2\u00A0up\u00C2\u00A0to\u00C2\u00A0at\u00C2\u00A0least\u00C2\u00A0300\u00C2\u00A0m.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0represented\u00C2\u00A0by\u00C2\u00A0massive\u00C2\u00A0(Fig.\u00C2\u00A02.8A)\u00C2\u00A0to\u00C2\u00A0flow\u00C2\u00A0banded\u00C2\u00A0lavas,\u00C2\u00A0domes\u00C2\u00A0or\u00C2\u00A0 dykes\u00C2\u00A0of\u00C2\u00A0dacitic\u00C2\u00A0to\u00C2\u00A0rhyolitic\u00C2\u00A0composition\u00C2\u00A0and\u00C2\u00A0are\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0a\u00C2\u00A0variety\u00C2\u00A0of\u00C2\u00A0volcaniclastic\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0 Breccia\u00C2\u00A0is\u00C2\u00A0common\u00C2\u00A0and\u00C2\u00A0varies\u00C2\u00A0from\u00C2\u00A0units\u00C2\u00A0of\u00C2\u00A0in\u00E2\u0080\u0090situ\u00C2\u00A0autoclastic\u00C2\u00A0breccia\u00C2\u00A0(Fig.\u00C2\u00A02.8B)\u00C2\u00A0to\u00C2\u00A0transported\u00C2\u00A0 deposits\u00C2\u00A0(Fig.\u00C2\u00A02.8C).\u00C2\u00A0\u00C2\u00A0Lava\u00C2\u00A0flow\u00E2\u0080\u0090dome\u00C2\u00A0complexes\u00C2\u00A0are\u00C2\u00A0dominated\u00C2\u00A0by\u00C2\u00A0buff\u00C2\u00A0to\u00C2\u00A0light\u00C2\u00A0grey,\u00C2\u00A0aphyric\u00C2\u00A0to\u00C2\u00A0 weakly\u00C2\u00A0feldspar\u00C2\u00A0porphyritic,\u00C2\u00A0rarely\u00C2\u00A0amygdaloidal,\u00C2\u00A0but\u00C2\u00A0locally\u00C2\u00A0spherulitic\u00C2\u00A0and\u00C2\u00A0perlitic\u00C2\u00A0dacite\u00E2\u0080\u0090 rhyolite.\u00C2\u00A0\u00C2\u00A0Textures\u00C2\u00A0indicate\u00C2\u00A0the\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0are\u00C2\u00A0mostly\u00C2\u00A0lavas\u00C2\u00A0and\u00C2\u00A0dykes\u00C2\u00A0with\u00C2\u00A0associated\u00C2\u00A0 in\u00E2\u0080\u0090situ\u00C2\u00A0breccias\u00C2\u00A0and\u00C2\u00A0proximal\u00C2\u00A0re\u00E2\u0080\u0090sedimented\u00C2\u00A0volcaniclastic\u00C2\u00A0units.\u00C2\u00A0\u00C2\u00A0Quartz\u00C2\u00A0porphyritic\u00C2\u00A0lavas\u00C2\u00A0are\u00C2\u00A0 not\u00C2\u00A0recognized\u00C2\u00A0near\u00C2\u00A0the\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0are\u00C2\u00A0generally\u00C2\u00A0uncommon\u00C2\u00A0throughout\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A036\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Lorenzo\u00C2\u00A0Formation.\u00C2\u00A0\u00C2\u00A0However,\u00C2\u00A0quartz\u00E2\u0080\u0090plagioclase\u00C2\u00A0porphyritic\u00C2\u00A0rhyolite\u00C2\u00A0forms\u00C2\u00A0late\u00C2\u00A0dykes\u00C2\u00A0or\u00C2\u00A0stocks\u00C2\u00A0 within\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0complex\u00C2\u00A0at\u00C2\u00A0TG1\u00C2\u00A0and\u00C2\u00A0elsewhere\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0formation.\u00C2\u00A0\u00C2\u00A0Dacitic\u00C2\u00A0lava\u00C2\u00A0flows\u00C2\u00A0and\u00C2\u00A0 breccias\u00C2\u00A0are\u00C2\u00A0conspicuous\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0immediate\u00C2\u00A0hanging\u00C2\u00A0wall\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0TG1\u00C2\u00A0and\u00C2\u00A0TG3\u00C2\u00A0deposits.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0 dacite\u00C2\u00A0is\u00C2\u00A0characterized\u00C2\u00A0by\u00C2\u00A0distinctive\u00C2\u00A0pale\u00C2\u00A0grey\u00E2\u0080\u0090green,\u00C2\u00A0aphyric\u00C2\u00A0to\u00C2\u00A0feldspar\u00C2\u00A0porphyritic\u00C2\u00A0textures,\u00C2\u00A0 and\u00C2\u00A0is\u00C2\u00A0commonly\u00C2\u00A0amygdule\u00E2\u0080\u0090rich\u00C2\u00A0(Fig.\u00C2\u00A02.8D).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Sedimentary\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0are\u00C2\u00A0limited\u00C2\u00A0to\u00C2\u00A0thin\u00E2\u0080\u0090bedded\u00C2\u00A0to\u00C2\u00A0 laminated,\u00C2\u00A0black,\u00C2\u00A0carbonaceous\u00C2\u00A0mudstones\u00C2\u00A0in\u00C2\u00A0less\u00C2\u00A0than\u00C2\u00A01\u00C2\u00A0m\u00E2\u0080\u0090thick\u00C2\u00A0units.\u00C2\u00A0\u00C2\u00A0Although\u00C2\u00A0 volumetrically\u00C2\u00A0minor,\u00C2\u00A0these\u00C2\u00A0pelagic\u00C2\u00A0sedimentary\u00C2\u00A0rocks\u00C2\u00A0are\u00C2\u00A0ubiquitous\u00C2\u00A0throughout\u00C2\u00A0this\u00C2\u00A0 formation.\u00C2\u00A0\u00C2\u00A0No\u00C2\u00A0other\u00C2\u00A0sedimentary\u00C2\u00A0rock\u00C2\u00A0types\u00C2\u00A0are\u00C2\u00A0known\u00C2\u00A0to\u00C2\u00A0occur\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 Formation.\u00C2\u00A0\u00C2\u00A0 2.5.2\u00C2\u00A0 Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation\u00C2\u00A0 Though\u00C2\u00A0the\u00C2\u00A0lower\u00C2\u00A0contact\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0is\u00C2\u00A0not\u00C2\u00A0exposed,\u00C2\u00A0the\u00C2\u00A0upper\u00C2\u00A0 contact\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0is\u00C2\u00A0conformable\u00C2\u00A0and\u00C2\u00A0relatively\u00C2\u00A0sharp.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0sequence\u00C2\u00A0has\u00C2\u00A0a\u00C2\u00A0 rather\u00C2\u00A0limited\u00C2\u00A0geographic\u00C2\u00A0distribution\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0western\u00E2\u0080\u0090central\u00C2\u00A0part\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0area\u00C2\u00A0and\u00C2\u00A0does\u00C2\u00A0not\u00C2\u00A0 extend\u00C2\u00A0north\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Las\u00C2\u00A0Lomas\u00C2\u00A0pluton\u00C2\u00A0(Fig.\u00C2\u00A02.4).\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0study\u00C2\u00A0restricts\u00C2\u00A0the\u00C2\u00A0rocks\u00C2\u00A0included\u00C2\u00A0therein\u00C2\u00A0 to\u00C2\u00A0those\u00C2\u00A0of\u00C2\u00A0similar\u00C2\u00A0character\u00C2\u00A0that\u00C2\u00A0outcrop\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0western\u00C2\u00A0side\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0study\u00C2\u00A0area\u00C2\u00A0(Figs.\u00C2\u00A04,\u00C2\u00A05).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0 Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation\u00C2\u00A0has\u00C2\u00A0an\u00C2\u00A0approximate\u00C2\u00A0thickness\u00C2\u00A0of\u00C2\u00A0up\u00C2\u00A0to\u00C2\u00A02,000m.\u00C2\u00A0 An\u00C2\u00A0entirely\u00C2\u00A0mafic\u00C2\u00A0volcanic\u00C2\u00A0sequence,\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation,\u00C2\u00A0is\u00C2\u00A0defined\u00C2\u00A0by\u00C2\u00A0distinctive\u00C2\u00A0 and\u00C2\u00A0monotonous\u00C2\u00A0coarse\u00C2\u00A0\u00E2\u0080\u0098crowded\u00E2\u0080\u0099\u00C2\u00A0feldspar\u00C2\u00A0porphyritic\u00C2\u00A0volcanic\u00C2\u00A0and\u00C2\u00A0breccia\u00C2\u00A0and\u00C2\u00A0minor\u00C2\u00A0 coherent\u00C2\u00A0lava.\u00C2\u00A0\u00C2\u00A0Subhedral\u00C2\u00A0feldspar\u00C2\u00A0phenocrysts\u00C2\u00A0to\u00C2\u00A0glomerocrysts\u00C2\u00A0range\u00C2\u00A0from\u00C2\u00A01\u00C2\u00A0mm\u00C2\u00A0to\u00C2\u00A0>10\u00C2\u00A0mm,\u00C2\u00A0 averaging\u00C2\u00A04\u00E2\u0080\u00905\u00C2\u00A0mm\u00C2\u00A0(Fig.\u00C2\u00A02.9A).\u00C2\u00A0\u00C2\u00A0Amygdaloidal\u00C2\u00A0lava\u00C2\u00A0flows\u00C2\u00A0are\u00C2\u00A0generally\u00C2\u00A0not\u00C2\u00A0common,\u00C2\u00A0though\u00C2\u00A0 amygdaloidal\u00C2\u00A0clasts\u00C2\u00A0are\u00C2\u00A0locally\u00C2\u00A0present\u00C2\u00A0in\u00C2\u00A0breccia.\u00C2\u00A0\u00C2\u00A0Volcaniclastic\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0this\u00C2\u00A0formation\u00C2\u00A0are\u00C2\u00A0 typically\u00C2\u00A0non\u00E2\u0080\u0090stratified,\u00C2\u00A0matrix\u00E2\u0080\u0090supported\u00C2\u00A0subangular\u00C2\u00A0to\u00C2\u00A0subround\u00C2\u00A0boulder\u00C2\u00A0breccia\u00C2\u00A0(Fig.\u00C2\u00A02.9B)\u00C2\u00A0or\u00C2\u00A0 cobble\u00E2\u0080\u0090\u00C2\u00A0to\u00C2\u00A0pebble\u00E2\u0080\u0090sized\u00C2\u00A0lithic\u00C2\u00A0and\u00C2\u00A0feldspar\u00C2\u00A0crystal\u00C2\u00A0tuff\u00C2\u00A0(Fig.\u00C2\u00A02.9C).\u00C2\u00A0\u00C2\u00A0Minor,\u00C2\u00A0thin\u00C2\u00A0bedded\u00C2\u00A0feldspar\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A037\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 (and\u00C2\u00A0rare\u00C2\u00A0pyroxene)\u00C2\u00A0crystal\u00C2\u00A0and\u00C2\u00A0ash\u00C2\u00A0tuff,\u00C2\u00A0possibly\u00C2\u00A0as\u00C2\u00A0re\u00E2\u0080\u0090worked\u00C2\u00A0material,\u00C2\u00A0occur\u00C2\u00A0near\u00C2\u00A0the\u00C2\u00A0upper\u00C2\u00A0 contact\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0formation\u00C2\u00A0(Fig.\u00C2\u00A02.9D).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0sequence\u00C2\u00A0is\u00C2\u00A0also\u00C2\u00A0distinctive\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0complete\u00C2\u00A0absence\u00C2\u00A0 of\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0and\u00C2\u00A0sedimentary\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0No\u00C2\u00A0pillow\u00C2\u00A0lava\u00C2\u00A0or\u00C2\u00A0autoclastic\u00C2\u00A0breccia\u00C2\u00A0similar\u00C2\u00A0to\u00C2\u00A0those\u00C2\u00A0 common\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0are\u00C2\u00A0known\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0 dominance\u00C2\u00A0of\u00C2\u00A0poorly\u00C2\u00A0vesicular,\u00C2\u00A0matrix\u00E2\u0080\u0090supported,\u00C2\u00A0non\u00E2\u0080\u0090stratified\u00C2\u00A0breccia,\u00C2\u00A0with\u00C2\u00A0distinctive\u00C2\u00A0 porphyritic\u00C2\u00A0juvenile\u00C2\u00A0and\u00C2\u00A0variably\u00C2\u00A0abraded\u00C2\u00A0clasts,\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0limited\u00C2\u00A0geographic\u00C2\u00A0extent\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0unit,\u00C2\u00A0 suggests\u00C2\u00A0the\u00C2\u00A0formation\u00C2\u00A0may\u00C2\u00A0be\u00C2\u00A0the\u00C2\u00A0result\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0diatreme\u00E2\u0080\u0090like\u00C2\u00A0process.\u00C2\u00A0 2.5.3\u00C2\u00A0 La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0 The\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0marks\u00C2\u00A0a\u00C2\u00A0return\u00C2\u00A0to\u00C2\u00A0bimodal\u00C2\u00A0volcanism\u00C2\u00A0of\u00C2\u00A0basaltic\u00E2\u0080\u0090andesite\u00C2\u00A0and\u00C2\u00A0 rhyolitic\u00C2\u00A0rocks,\u00C2\u00A0albeit\u00C2\u00A0with\u00C2\u00A0a\u00C2\u00A0greater\u00C2\u00A0abundance\u00C2\u00A0of\u00C2\u00A0volcaniclastic\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0presence\u00C2\u00A0of\u00C2\u00A0 pyroclastic\u00C2\u00A0deposits,\u00C2\u00A0including\u00C2\u00A0crystal\u00E2\u0080\u0090rich\u00C2\u00A0tuff,\u00C2\u00A0may\u00C2\u00A0indicate\u00C2\u00A0a\u00C2\u00A0shift\u00C2\u00A0to\u00C2\u00A0a\u00C2\u00A0relatively\u00C2\u00A0more\u00C2\u00A0shallow\u00C2\u00A0 water\u00C2\u00A0depositional\u00C2\u00A0setting.\u00C2\u00A0\u00C2\u00A0Reyes\u00C2\u00A0and\u00C2\u00A0Caldas\u00C2\u00A0(1987)\u00C2\u00A0report\u00C2\u00A0an\u00C2\u00A0upper\u00C2\u00A0Albian\u00C2\u00A0age\u00C2\u00A0for\u00C2\u00A0this\u00C2\u00A0 sequence\u00C2\u00A0based\u00C2\u00A0on\u00C2\u00A0fossil\u00C2\u00A0evidence.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0has\u00C2\u00A0an\u00C2\u00A0estimated\u00C2\u00A0thickness\u00C2\u00A0of\u00C2\u00A0 3500\u00C2\u00A0m\u00C2\u00A0with\u00C2\u00A0conformable\u00C2\u00A0upper\u00C2\u00A0and\u00C2\u00A0lower\u00C2\u00A0contacts.\u00C2\u00A0 Mafic\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0this\u00C2\u00A0unit\u00C2\u00A0include\u00C2\u00A0highly\u00C2\u00A0vesicular,\u00C2\u00A0thick\u00C2\u00A0flows\u00C2\u00A0and\u00C2\u00A0dykes\u00C2\u00A0(Fig.\u00C2\u00A02.10A)\u00C2\u00A0with\u00C2\u00A0well\u00C2\u00A0 developed\u00C2\u00A0flow\u00C2\u00A0foliations\u00C2\u00A0(Fig.\u00C2\u00A02.10B).\u00C2\u00A0\u00C2\u00A0Flows\u00C2\u00A0are\u00C2\u00A0observed\u00C2\u00A0to\u00C2\u00A0grade\u00C2\u00A0into\u00C2\u00A0autoclastic\u00C2\u00A0deposits\u00C2\u00A0of\u00C2\u00A0 unsorted\u00C2\u00A0coarse\u00C2\u00A0breccia\u00C2\u00A0(Fig.\u00C2\u00A02.10C).\u00C2\u00A0\u00C2\u00A0\u00E2\u0080\u0098Breadcrust\u00E2\u0080\u0099\u00C2\u00A0texture\u00C2\u00A0is\u00C2\u00A0illustrated\u00C2\u00A0by\u00C2\u00A0chilled\u00C2\u00A0and\u00C2\u00A0fractured\u00C2\u00A0 margins\u00C2\u00A0of\u00C2\u00A0lava\u00C2\u00A0flows\u00C2\u00A0with\u00C2\u00A0interstitial\u00C2\u00A0hyaloclastic\u00C2\u00A0breccia\u00C2\u00A0(Fig.\u00C2\u00A02.10D).\u00C2\u00A0\u00C2\u00A0Pillow\u00C2\u00A0lava\u00C2\u00A0is\u00C2\u00A0present\u00C2\u00A0in\u00C2\u00A0 only\u00C2\u00A0a\u00C2\u00A0few\u00C2\u00A0localities.\u00C2\u00A0\u00C2\u00A0However,\u00C2\u00A0polygonal\u00C2\u00A0jointed\u00C2\u00A0mafic\u00C2\u00A0lava\u00C2\u00A0flow\u00C2\u00A0lobes,\u00C2\u00A0apophyses\u00C2\u00A0and\u00C2\u00A0dykes\u00C2\u00A0 into\u00C2\u00A0volcaniclastic\u00C2\u00A0deposits\u00C2\u00A0or\u00C2\u00A0felsic\u00C2\u00A0crystal\u00C2\u00A0tuffs\u00C2\u00A0(Fig.\u00C2\u00A02.10E)\u00C2\u00A0are\u00C2\u00A0common.\u00C2\u00A0 Felsic\u00C2\u00A0rocks\u00C2\u00A0range\u00C2\u00A0from\u00C2\u00A0coherent\u00C2\u00A0facies\u00C2\u00A0of\u00C2\u00A0quartz\u00E2\u0080\u0090\u00C2\u00A0and/or\u00C2\u00A0feldspar\u00E2\u0080\u0090\u00C2\u00A0porphyritic\u00C2\u00A0lava\u00C2\u00A0(lava\u00C2\u00A0 flows,\u00C2\u00A0domes,\u00C2\u00A0dykes)\u00C2\u00A0to\u00C2\u00A0crystal\u00E2\u0080\u0090,\u00C2\u00A0lithic\u00E2\u0080\u0090,\u00C2\u00A0and\u00C2\u00A0pumice\u00E2\u0080\u0090bearing\u00C2\u00A0tuffs\u00C2\u00A0(Figs.\u00C2\u00A02.10F,\u00C2\u00A0G).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0 Formation\u00C2\u00A0is\u00C2\u00A0the\u00C2\u00A0only\u00C2\u00A0sequence\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0to\u00C2\u00A0include\u00C2\u00A0felsic\u00C2\u00A0tuffaceous\u00C2\u00A0rocks\u00C2\u00A0 indicative\u00C2\u00A0of\u00C2\u00A0pyroclastic\u00C2\u00A0eruptions.\u00C2\u00A0\u00C2\u00A0Another\u00C2\u00A0enigmatic\u00C2\u00A0feature\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0is\u00C2\u00A0that\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A038\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 granitic\u00C2\u00A0xenoliths\u00C2\u00A0are\u00C2\u00A0present\u00C2\u00A0in\u00C2\u00A0several\u00C2\u00A0flows\u00C2\u00A0and\u00C2\u00A0were\u00C2\u00A0derived\u00C2\u00A0either\u00C2\u00A0from\u00C2\u00A0older\u00C2\u00A0crustal\u00C2\u00A0 basement\u00C2\u00A0or\u00C2\u00A0from\u00C2\u00A0related\u00C2\u00A0igneous\u00C2\u00A0plutonic\u00C2\u00A0roots\u00C2\u00A0carried\u00C2\u00A0in\u00C2\u00A0penecontemporaneous\u00C2\u00A0eruptions.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Volcaniclastic\u00C2\u00A0rocks\u00C2\u00A0make\u00C2\u00A0up\u00C2\u00A0a\u00C2\u00A0significant\u00C2\u00A0proportion\u00C2\u00A0of\u00C2\u00A0this\u00C2\u00A0unit,\u00C2\u00A0and\u00C2\u00A0range\u00C2\u00A0from\u00C2\u00A0chaotic,\u00C2\u00A0 matrix\u00E2\u0080\u0090supported,\u00C2\u00A0boulder\u00E2\u0080\u0090size\u00C2\u00A0breccia\u00C2\u00A0(Fig.\u00C2\u00A02.10H)\u00C2\u00A0to\u00C2\u00A0well\u00C2\u00A0sorted,\u00C2\u00A0pebble\u00E2\u0080\u0090size\u00C2\u00A0breccia\u00C2\u00A0and\u00C2\u00A0 decimeters\u00E2\u0080\u0090thick\u00C2\u00A0cross\u00E2\u0080\u0090bedded\u00C2\u00A0volcanic\u00C2\u00A0sandstone\u00C2\u00A0(Fig.\u00C2\u00A02.10I).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0boulder\u00C2\u00A0breccia\u00C2\u00A0occurs\u00C2\u00A0as\u00C2\u00A0 either\u00C2\u00A0talus\u00C2\u00A0deposits\u00C2\u00A0related\u00C2\u00A0to\u00C2\u00A0fault\u00C2\u00A0scarps\u00C2\u00A0or\u00C2\u00A0mass\u00C2\u00A0flows.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0well\u00E2\u0080\u0090sorted,\u00C2\u00A0coarse\u00C2\u00A0clastic\u00C2\u00A0rocks\u00C2\u00A0 suggest\u00C2\u00A0a\u00C2\u00A0high\u00C2\u00A0energy\u00C2\u00A0shallow\u00C2\u00A0marine\u00C2\u00A0to\u00C2\u00A0fluvial\u00C2\u00A0environment.\u00C2\u00A0\u00C2\u00A0Basaltic\u00E2\u0080\u0090andesite\u00C2\u00A0generally\u00C2\u00A0 dominates\u00C2\u00A0the\u00C2\u00A0clast\u00C2\u00A0composition,\u00C2\u00A0though\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0clasts\u00C2\u00A0are\u00C2\u00A0common.\u00C2\u00A0\u00C2\u00A0Locally,\u00C2\u00A0calcareous\u00C2\u00A0 sedimentary\u00C2\u00A0clasts\u00C2\u00A0are\u00C2\u00A0abundant\u00C2\u00A0and\u00C2\u00A0occur\u00C2\u00A0as\u00C2\u00A0blocks\u00C2\u00A0up\u00C2\u00A0to\u00C2\u00A0boulder\u00C2\u00A0size.\u00C2\u00A0\u00C2\u00A0Mafic\u00C2\u00A0and\u00C2\u00A0felsic\u00C2\u00A0 volcanic\u00C2\u00A0rocks\u00C2\u00A0are\u00C2\u00A0intercalated\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0volcaniclastic\u00C2\u00A0units\u00C2\u00A0and\u00C2\u00A0suggest\u00C2\u00A0volcanism\u00C2\u00A0was\u00C2\u00A0also\u00C2\u00A0 active\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0shallow\u00C2\u00A0marine\u00C2\u00A0setting.\u00C2\u00A0 2.5.4\u00C2\u00A0 Lancones\u00C2\u00A0Formation\u00C2\u00A0 The\u00C2\u00A0Lancones\u00C2\u00A0Formation\u00C2\u00A0consisting\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0basal\u00C2\u00A0sequences\u00C2\u00A0of\u00C2\u00A0polylithic,\u00C2\u00A0basaltic\u00E2\u0080\u0090andesite\u00E2\u0080\u0090rich,\u00C2\u00A0 volcaniclastic\u00C2\u00A0units\u00C2\u00A0represent\u00C2\u00A0deposition\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0relatively\u00C2\u00A0shallow\u00C2\u00A0marine\u00C2\u00A0environment.\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0 thick\u00E2\u0080\u0090bedded\u00C2\u00A0and\u00C2\u00A0variably\u00C2\u00A0stratified\u00C2\u00A0breccias\u00C2\u00A0are\u00C2\u00A0intercalated\u00C2\u00A0with\u00C2\u00A0siliciclastic\u00C2\u00A0and\u00C2\u00A0calcareous\u00C2\u00A0 sedimentary\u00C2\u00A0units,\u00C2\u00A0including\u00C2\u00A0limestones,\u00C2\u00A0calcareous\u00C2\u00A0sandstones,\u00C2\u00A0siltstone\u00C2\u00A0and\u00C2\u00A0greywacke\u00C2\u00A0(Fig.\u00C2\u00A0 2.11A,\u00C2\u00A0B).\u00C2\u00A0\u00C2\u00A0Sedimentary\u00C2\u00A0rocks\u00C2\u00A0become\u00C2\u00A0more\u00C2\u00A0abundant\u00C2\u00A0towards\u00C2\u00A0the\u00C2\u00A0top\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0unit.\u00C2\u00A0\u00C2\u00A0Reyes\u00C2\u00A0and\u00C2\u00A0 Caldas\u00C2\u00A0(1987)\u00C2\u00A0report\u00C2\u00A0fossils\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0age\u00C2\u00A0range\u00C2\u00A0of\u00C2\u00A0late\u00C2\u00A0Albian\u00C2\u00A0and\u00C2\u00A0Early\u00C2\u00A0Cenomanian.\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0rocks\u00C2\u00A0 are\u00C2\u00A0considered\u00C2\u00A0to\u00C2\u00A0be\u00C2\u00A0gradational\u00C2\u00A0into\u00C2\u00A0the\u00C2\u00A0forearc\u00C2\u00A0sedimentary\u00C2\u00A0sequences\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Copa\u00C2\u00A0Sombrero\u00C2\u00A0 Group\u00C2\u00A0senso\u00C2\u00A0lato\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0western\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0(Fig.\u00C2\u00A02.4,\u00C2\u00A011).\u00C2\u00A0 2.6\u00C2\u00A0 Structural\u00C2\u00A0Geology\u00C2\u00A0 The\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0is\u00C2\u00A0situated\u00C2\u00A0at\u00C2\u00A0a\u00C2\u00A0major\u00C2\u00A0oroclinal\u00C2\u00A0bend\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0Andean\u00C2\u00A0chain\u00C2\u00A0known\u00C2\u00A0as\u00C2\u00A0 Huancabamba\u00C2\u00A0deflection\u00C2\u00A0(M\u00C3\u00A9gard,\u00C2\u00A01987),\u00C2\u00A0where\u00C2\u00A0the\u00C2\u00A0Andes\u00C2\u00A0trend\u00C2\u00A0changes\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0north\u00E2\u0080\u0090 northwest\u00C2\u00A0in\u00C2\u00A0northern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0to\u00C2\u00A0north\u00E2\u0080\u0090northeast\u00C2\u00A0in\u00C2\u00A0Ecuador\u00C2\u00A0(Fig.\u00C2\u00A02.2).\u00C2\u00A0\u00C2\u00A0Several\u00C2\u00A0clockwise\u00C2\u00A0rotations\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A039\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 are\u00C2\u00A0documented\u00C2\u00A0north\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Huancabamba\u00C2\u00A0deflection,\u00C2\u00A0including\u00C2\u00A0~25\u00E2\u0080\u009030\u00C2\u00B0\u00C2\u00A0and\u00C2\u00A0~25\u00C2\u00B0\u00C2\u00A0in\u00C2\u00A0 Cretaceous\u00E2\u0080\u0090Tertiary\u00C2\u00A0and\u00C2\u00A0Tertiary\u00C2\u00A0times,\u00C2\u00A0respectively\u00C2\u00A0(Mourier\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01988;\u00C2\u00A0Mitouard\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A0 1990).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0kinematics\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0deformation\u00C2\u00A0are\u00C2\u00A0poorly\u00C2\u00A0understood\u00C2\u00A0but\u00C2\u00A0suggest\u00C2\u00A0the\u00C2\u00A0opening\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0may\u00C2\u00A0have\u00C2\u00A0been\u00C2\u00A0an\u00C2\u00A0integral\u00C2\u00A0part\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Huancabamba\u00C2\u00A0deflection.\u00C2\u00A0\u00C2\u00A0Part\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 rotation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Amotape\u00C2\u00A0block\u00C2\u00A0was\u00C2\u00A0suggested\u00C2\u00A0by\u00C2\u00A0Mourier\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1988)\u00C2\u00A0to\u00C2\u00A0have\u00C2\u00A0happened\u00C2\u00A0in\u00E2\u0080\u0090situ\u00C2\u00A0 and\u00C2\u00A0related\u00C2\u00A0to\u00C2\u00A0accretion.\u00C2\u00A0\u00C2\u00A0Under\u00C2\u00A0the\u00C2\u00A0model\u00C2\u00A0presented\u00C2\u00A0(Fig.\u00C2\u00A02.3C),\u00C2\u00A0the\u00C2\u00A0opening\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0 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from\u00C2\u00A0that\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0WPT\u00C2\u00A0with\u00C2\u00A0respect\u00C2\u00A0to\u00C2\u00A0an\u00C2\u00A0original\u00C2\u00A0NNW\u00E2\u0080\u0090trending\u00C2\u00A0geometry.\u00C2\u00A0 Several\u00C2\u00A0deformation\u00C2\u00A0events\u00C2\u00A0are\u00C2\u00A0recognized\u00C2\u00A0in\u00C2\u00A0northwestern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0in\u00C2\u00A0Late\u00C2\u00A0Cretaceous\u00C2\u00A0and\u00C2\u00A0 Tertiary\u00C2\u00A0times\u00C2\u00A0(Jaillard\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01999),\u00C2\u00A0including\u00C2\u00A0a\u00C2\u00A0mid\u00E2\u0080\u0090\u00C2\u00A0to\u00C2\u00A0late\u00E2\u0080\u0090Albian\u00C2\u00A0tectonic\u00C2\u00A0phase\u00C2\u00A0correlated\u00C2\u00A0 with\u00C2\u00A0the\u00C2\u00A0Mochica\u00C2\u00A0orogeny\u00C2\u00A0defined\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0central\u00E2\u0080\u0090northern\u00C2\u00A0Andes\u00C2\u00A0(M\u00C3\u00A9gard,\u00C2\u00A01984).\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0 deformation\u00C2\u00A0is\u00C2\u00A0manifested\u00C2\u00A0mostly\u00C2\u00A0as\u00C2\u00A0broad\u00C2\u00A0open\u00C2\u00A0folds\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0eastern\u00C2\u00A0Lancones\u00C2\u00A0basin,\u00C2\u00A0in\u00C2\u00A0general\u00C2\u00A0 with\u00C2\u00A0northeast\u00E2\u0080\u0090southwest\u00C2\u00A0striking,\u00C2\u00A0\u00E2\u0080\u0098Andean\u00E2\u0080\u0090normal\u00E2\u0080\u0099,\u00C2\u00A0fold\u00C2\u00A0axes\u00C2\u00A0(Figs.\u00C2\u00A04,\u00C2\u00A05).\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0series\u00C2\u00A0of\u00C2\u00A0WNW\u00E2\u0080\u0090 trending\u00C2\u00A0topographic\u00C2\u00A0lineaments\u00C2\u00A0are\u00C2\u00A0identifiable\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0satellite\u00C2\u00A0data,\u00C2\u00A0but\u00C2\u00A0do\u00C2\u00A0not\u00C2\u00A0appear\u00C2\u00A0to\u00C2\u00A0 have\u00C2\u00A0resulted\u00C2\u00A0in\u00C2\u00A0any\u00C2\u00A0mapable\u00C2\u00A0displacement\u00C2\u00A0(Fig.\u00C2\u00A02.4).\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0linears\u00C2\u00A0may\u00C2\u00A0be\u00C2\u00A0representative\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0same\u00C2\u00A0fracture\u00C2\u00A0system\u00C2\u00A0that\u00C2\u00A0controlled\u00C2\u00A0the\u00C2\u00A0emplacement\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0plutonic\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Data\u00C2\u00A0derived\u00C2\u00A0from\u00C2\u00A0oil\u00C2\u00A0exploration\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0basin\u00C2\u00A0(Fig.\u00C2\u00A02.1)\u00C2\u00A0provides\u00C2\u00A0additional\u00C2\u00A0constraints\u00C2\u00A0 on\u00C2\u00A0the\u00C2\u00A0Mesozoic\u00C2\u00A0structural\u00C2\u00A0history\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0area.\u00C2\u00A0\u00C2\u00A0Alencastre\u00C2\u00A0(1980)\u00C2\u00A0reported\u00C2\u00A0a\u00C2\u00A0number\u00C2\u00A0of\u00C2\u00A0faults,\u00C2\u00A0 interpreted\u00C2\u00A0from\u00C2\u00A0petroleum\u00C2\u00A0borehole\u00C2\u00A0and\u00C2\u00A0geophysical\u00C2\u00A0data\u00C2\u00A0to\u00C2\u00A0be\u00C2\u00A0as\u00C2\u00A0normal\u00C2\u00A0or\u00C2\u00A0block\u00C2\u00A0and\u00C2\u00A0 transcurrent\u00C2\u00A0faults.\u00C2\u00A0\u00C2\u00A0Seismically\u00C2\u00A0imaged\u00C2\u00A0faults\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Tertiary\u00C2\u00A0as\u00C2\u00A0well\u00C2\u00A0as\u00C2\u00A0Cretaceous\u00C2\u00A0strata\u00C2\u00A0strike\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A040\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 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clear,\u00C2\u00A0colorless,\u00C2\u00A0stubby\u00C2\u00A0to\u00C2\u00A0elongate,\u00C2\u00A0euhedral\u00C2\u00A0prisms.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0sample\u00C2\u00A0produced\u00C2\u00A0a\u00C2\u00A0small\u00C2\u00A0yield\u00C2\u00A0of\u00C2\u00A0<74\u00C2\u00A0 \u00C2\u00B5m\u00C2\u00A0zircons\u00C2\u00A0that\u00C2\u00A0appear\u00C2\u00A0entirely\u00C2\u00A0magmatic.\u00C2\u00A0\u00C2\u00A0Twelve\u00C2\u00A0grains\u00C2\u00A0were\u00C2\u00A0analyzed\u00C2\u00A0by\u00C2\u00A0SHRIMP\u00E2\u0080\u0090RG\u00C2\u00A0of\u00C2\u00A0 which\u00C2\u00A0three\u00C2\u00A0data\u00C2\u00A0points\u00C2\u00A0cluster\u00C2\u00A0at\u00C2\u00A0slightly\u00C2\u00A0lower\u00C2\u00A0ages\u00C2\u00A0and\u00C2\u00A0one\u00C2\u00A0slightly\u00C2\u00A0higher\u00C2\u00A0than\u00C2\u00A0the\u00C2\u00A0main\u00C2\u00A0 population\u00C2\u00A0and\u00C2\u00A0these\u00C2\u00A0were\u00C2\u00A0omitted\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0age\u00C2\u00A0calculation.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0weighted\u00C2\u00A0mean\u00C2\u00A0206Pb/238U\u00C2\u00A0 age\u00C2\u00A0of\u00C2\u00A0eight\u00C2\u00A0analyses\u00C2\u00A0is\u00C2\u00A0104.8\u00C2\u00A0\u00C2\u00B1\u00C2\u00A01.3\u00C2\u00A0Ma\u00C2\u00A0with\u00C2\u00A0MSWD\u00C2\u00A0of\u00C2\u00A01.8\u00C2\u00A0(Fig.\u00C2\u00A02.13A).\u00C2\u00A0 Sample\u00C2\u00A0LW\u00E2\u0080\u0090016\u00C2\u00A0(quartz\u00C2\u00A0porphyritic\u00C2\u00A0rhyolite\u00C2\u00A0dyke)\u00C2\u00A0was\u00C2\u00A0also\u00C2\u00A0dated\u00C2\u00A0by\u00C2\u00A0SHRIMP\u00E2\u0080\u0090RG\u00C2\u00A0analysis.\u00C2\u00A0\u00C2\u00A0 All\u00C2\u00A0crystals\u00C2\u00A0appear\u00C2\u00A0to\u00C2\u00A0be\u00C2\u00A0devoid\u00C2\u00A0of\u00C2\u00A0xenocrysts\u00C2\u00A0and\u00C2\u00A0display\u00C2\u00A0well\u00C2\u00A0developed\u00C2\u00A0oscillatory\u00C2\u00A0to\u00C2\u00A0lamellar\u00C2\u00A0 zoning\u00C2\u00A0under\u00C2\u00A0cathodoluminescence\u00C2\u00A0(CL;\u00C2\u00A0Appendix\u00C2\u00A0A).\u00C2\u00A0\u00C2\u00A0Excluding\u00C2\u00A0two\u00C2\u00A0samples\u00C2\u00A0that\u00C2\u00A0have\u00C2\u00A0slightly\u00C2\u00A0 higher\u00C2\u00A0206Pb/238U\u00C2\u00A0ages\u00C2\u00A0than\u00C2\u00A0the\u00C2\u00A0main\u00C2\u00A0population,\u00C2\u00A0ten\u00C2\u00A0analyses\u00C2\u00A0of\u00C2\u00A0both\u00C2\u00A0cores\u00C2\u00A0and\u00C2\u00A0rims\u00C2\u00A0yield\u00C2\u00A0a\u00C2\u00A0 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Ma,\u00C2\u00A0which\u00C2\u00A0is\u00C2\u00A0interpreted\u00C2\u00A0to\u00C2\u00A0be\u00C2\u00A0the\u00C2\u00A0best\u00C2\u00A0estimate\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0crystallization\u00C2\u00A0age\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0sample.\u00C2\u00A0\u00C2\u00A0 Fractions\u00C2\u00A0E\u00C2\u00A0and\u00C2\u00A0F\u00C2\u00A0have\u00C2\u00A0suffered\u00C2\u00A0minor\u00C2\u00A0post\u00E2\u0080\u0090crystallization\u00C2\u00A0Pb\u00E2\u0080\u0090loss,\u00C2\u00A0and\u00C2\u00A0fractions\u00C2\u00A0A\u00C2\u00A0and\u00C2\u00A0D\u00C2\u00A0gave\u00C2\u00A0 discordant\u00C2\u00A0analyses\u00C2\u00A0with\u00C2\u00A0older\u00C2\u00A0207Pb/206Pb\u00C2\u00A0ages,\u00C2\u00A0indicating\u00C2\u00A0the\u00C2\u00A0presence\u00C2\u00A0of\u00C2\u00A0minor\u00C2\u00A0older\u00C2\u00A0 inherited\u00C2\u00A0zircon\u00C2\u00A0components\u00C2\u00A0in\u00C2\u00A0these\u00C2\u00A0fractions.\u00C2\u00A0 Sample\u00C2\u00A0LW\u00E2\u0080\u0090013\u00C2\u00A0is\u00C2\u00A0a\u00C2\u00A0quartz\u00C2\u00A0porphyritic\u00C2\u00A0rhyolite\u00C2\u00A0dyke\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0upper\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 Formation\u00C2\u00A0near\u00C2\u00A0the\u00C2\u00A0contact\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation.\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0small\u00C2\u00A0quantity\u00C2\u00A0of\u00C2\u00A0zircons\u00C2\u00A0was\u00C2\u00A0 recovered.\u00C2\u00A0\u00C2\u00A0CL\u00C2\u00A0images\u00C2\u00A0indicate\u00C2\u00A0that\u00C2\u00A0a\u00C2\u00A0few\u00C2\u00A0crystals\u00C2\u00A0have\u00C2\u00A0small\u00C2\u00A0xenocrystic\u00C2\u00A0cores,\u00C2\u00A0though\u00C2\u00A0most\u00C2\u00A0 display\u00C2\u00A0simple\u00C2\u00A0oscillatory\u00C2\u00A0zoning\u00C2\u00A0(Appendix\u00C2\u00A0A).\u00C2\u00A0\u00C2\u00A0SHRIMP\u00E2\u0080\u0090RG\u00C2\u00A0analyses\u00C2\u00A0of\u00C2\u00A0twelve\u00C2\u00A0crystals\u00C2\u00A0yield\u00C2\u00A0no\u00C2\u00A0 systematic\u00C2\u00A0measurable\u00C2\u00A0difference\u00C2\u00A0in\u00C2\u00A0ages\u00C2\u00A0between\u00C2\u00A0cores\u00C2\u00A0and\u00C2\u00A0rims\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0wholly\u00C2\u00A0magmatic\u00C2\u00A0 crystals\u00C2\u00A0but\u00C2\u00A0show\u00C2\u00A0some\u00C2\u00A0scatter\u00C2\u00A0between\u00C2\u00A0206Pb/238U\u00C2\u00A0ages\u00C2\u00A0of\u00C2\u00A096.6\u00C2\u00A0and\u00C2\u00A0104.6\u00C2\u00A0Ma.\u00C2\u00A0\u00C2\u00A0Three\u00C2\u00A0analyses\u00C2\u00A0 with\u00C2\u00A0slightly\u00C2\u00A0higher\u00C2\u00A0206Pb/238U\u00C2\u00A0ages\u00C2\u00A0than\u00C2\u00A0the\u00C2\u00A0main\u00C2\u00A0population\u00C2\u00A0were\u00C2\u00A0rejected\u00C2\u00A0and\u00C2\u00A0are\u00C2\u00A0likely\u00C2\u00A0 xenocrystic.\u00C2\u00A0\u00C2\u00A0As\u00C2\u00A0there\u00C2\u00A0is\u00C2\u00A0no\u00C2\u00A0geologic\u00C2\u00A0reason\u00C2\u00A0to\u00C2\u00A0reject\u00C2\u00A0any\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0remaining\u00C2\u00A0zircon\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0ages,\u00C2\u00A0a\u00C2\u00A0 weighted\u00C2\u00A0average\u00C2\u00A0206Pb/238U\u00C2\u00A0age\u00C2\u00A0of\u00C2\u00A099.8\u00C2\u00A0\u00C2\u00B1\u00C2\u00A01.6\u00C2\u00A0with\u00C2\u00A0MSWD\u00C2\u00A0of\u00C2\u00A03.2\u00C2\u00A0is\u00C2\u00A0calculated\u00C2\u00A0(Fig.\u00C2\u00A02.13C).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0 high\u00C2\u00A0MSWD\u00C2\u00A0reflects\u00C2\u00A0the\u00C2\u00A0scatter\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0data.\u00C2\u00A0 Most\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0zircons\u00C2\u00A0from\u00C2\u00A0sample\u00C2\u00A0LW\u00E2\u0080\u0090078\u00C2\u00A0(quartz\u00E2\u0080\u0090feldspar\u00C2\u00A0porphyritic\u00C2\u00A0clast\u00C2\u00A0in\u00C2\u00A0polylithic\u00C2\u00A0 breccia)\u00C2\u00A0have\u00C2\u00A0CL\u00C2\u00A0patterns\u00C2\u00A0that\u00C2\u00A0suggest\u00C2\u00A0entirely\u00C2\u00A0magmatic\u00C2\u00A0phases\u00C2\u00A0with\u00C2\u00A0oscillatory\u00C2\u00A0to\u00C2\u00A0lamellar\u00C2\u00A0 zoning\u00C2\u00A0in\u00C2\u00A0igneous\u00C2\u00A0cores,\u00C2\u00A0though\u00C2\u00A0several\u00C2\u00A0grains\u00C2\u00A0have\u00C2\u00A0inherited\u00C2\u00A0zircon\u00C2\u00A0cores\u00C2\u00A0(Appendix\u00C2\u00A0A).\u00C2\u00A0\u00C2\u00A0Twelve\u00C2\u00A0 crystals\u00C2\u00A0were\u00C2\u00A0analyzed\u00C2\u00A0by\u00C2\u00A0SHRIMP\u00E2\u0080\u0090RG.\u00C2\u00A0\u00C2\u00A0Sample\u00C2\u00A0point\u00C2\u00A01\u00C2\u00A0yielded\u00C2\u00A0a\u00C2\u00A0slightly\u00C2\u00A0younger\u00C2\u00A0age\u00C2\u00A0(95.4\u00C2\u00A0Ma)\u00C2\u00A0 than\u00C2\u00A0the\u00C2\u00A0main\u00C2\u00A0trend,\u00C2\u00A0possible\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0Pb\u00E2\u0080\u0090loss\u00C2\u00A0though\u00C2\u00A0it\u00C2\u00A0was\u00C2\u00A0an\u00C2\u00A0analysis\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0zircon\u00C2\u00A0crystal\u00C2\u00A0core,\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A044\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 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Sample\u00C2\u00A0LW\u00E2\u0080\u0090077\u00C2\u00A0(dacite\u00C2\u00A0flow\u00C2\u00A0and\u00C2\u00A0autobreccia)\u00C2\u00A0contained\u00C2\u00A0abundant\u00C2\u00A0zircons\u00C2\u00A0and\u00C2\u00A0was\u00C2\u00A0analyzed\u00C2\u00A0 by\u00C2\u00A0TIMS\u00C2\u00A0with\u00C2\u00A0six\u00C2\u00A0fractions\u00C2\u00A0all\u00C2\u00A0giving\u00C2\u00A0concordant\u00C2\u00A0analyses\u00C2\u00A0(Fig.\u00C2\u00A02.14D).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0analyses\u00C2\u00A0scatter\u00C2\u00A0along\u00C2\u00A0 Concordia,\u00C2\u00A0however,\u00C2\u00A0likely\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0variable\u00C2\u00A0effects\u00C2\u00A0of\u00C2\u00A0post\u00E2\u0080\u0090crystallization\u00C2\u00A0Pb\u00E2\u0080\u0090loss\u00C2\u00A0that\u00C2\u00A0were\u00C2\u00A0not\u00C2\u00A0 completely\u00C2\u00A0eliminated\u00C2\u00A0by\u00C2\u00A0strong\u00C2\u00A0air\u00C2\u00A0abrasion.\u00C2\u00A0\u00C2\u00A0Assuming\u00C2\u00A0that\u00C2\u00A0no\u00C2\u00A0older\u00C2\u00A0inherited\u00C2\u00A0zircon\u00C2\u00A0cores\u00C2\u00A0are\u00C2\u00A0 present\u00C2\u00A0in\u00C2\u00A0any\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0grains,\u00C2\u00A0a\u00C2\u00A0minimum\u00C2\u00A0crystallization\u00C2\u00A0age\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0sample\u00C2\u00A0is\u00C2\u00A0given\u00C2\u00A0by\u00C2\u00A0the\u00C2\u00A0oldest\u00C2\u00A0 206Pb/238U\u00C2\u00A0age\u00C2\u00A0(for\u00C2\u00A0fraction\u00C2\u00A0B)\u00C2\u00A0at\u00C2\u00A095.0\u00C2\u00A0\u00C2\u00B1\u00C2\u00A00.5\u00C2\u00A0Ma.\u00C2\u00A0 Most\u00C2\u00A0zircons\u00C2\u00A0from\u00C2\u00A0sample\u00C2\u00A0LW\u00E2\u0080\u0090043\u00C2\u00A0(rhyolite\u00C2\u00A0quartz\u00E2\u0080\u0090feldspar\u00C2\u00A0porphyritic\u00C2\u00A0flow)\u00C2\u00A0in\u00C2\u00A0CL\u00C2\u00A0imagery\u00C2\u00A0 display\u00C2\u00A0inherited\u00C2\u00A0cores\u00C2\u00A0represented\u00C2\u00A0by\u00C2\u00A0dark,\u00C2\u00A0resorbed\u00C2\u00A0zones\u00C2\u00A0with\u00C2\u00A0oscillatory\u00C2\u00A0zoned\u00C2\u00A0overgrowths\u00C2\u00A0 (Appendix\u00C2\u00A0A).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0sample\u00C2\u00A0was\u00C2\u00A0dated\u00C2\u00A0using\u00C2\u00A0SHRIMP\u00E2\u0080\u0090RG\u00C2\u00A0with\u00C2\u00A0nearly\u00C2\u00A0all\u00C2\u00A0data\u00C2\u00A0points\u00C2\u00A0selected\u00C2\u00A0from\u00C2\u00A0 crystal\u00C2\u00A0rims.\u00C2\u00A0\u00C2\u00A0Two\u00C2\u00A0of\u00C2\u00A012\u00C2\u00A0data\u00C2\u00A0points\u00C2\u00A0yield\u00C2\u00A0substantially\u00C2\u00A0younger\u00C2\u00A0ages\u00C2\u00A0(due\u00C2\u00A0to\u00C2\u00A0possible\u00C2\u00A0significant\u00C2\u00A0 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2.9.1\u00C2\u00A0 Depositional\u00C2\u00A0Evolution\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0 The\u00C2\u00A0~10\u00C2\u00A0km\u00C2\u00A0thick\u00C2\u00A0stratigraphic\u00C2\u00A0package\u00C2\u00A0that\u00C2\u00A0defines\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0sequence\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 Lancones\u00C2\u00A0Basin\u00C2\u00A0represents\u00C2\u00A0a\u00C2\u00A0large\u00C2\u00A0bimodal\u00C2\u00A0volcanic\u00C2\u00A0eruptive\u00C2\u00A0event\u00C2\u00A0in\u00C2\u00A0mid\u00E2\u0080\u0090Cretaceous\u00C2\u00A0times\u00C2\u00A0 within\u00C2\u00A0a\u00C2\u00A0marginal\u00C2\u00A0basin\u00C2\u00A0that\u00C2\u00A0presently\u00C2\u00A0is\u00C2\u00A0150\u00C2\u00A0km\u00C2\u00A0wide.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0stratigraphy\u00C2\u00A0suggests\u00C2\u00A0a\u00C2\u00A0progressively\u00C2\u00A0 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the\u00C2\u00A0absence\u00C2\u00A0of\u00C2\u00A0pyroclastic\u00C2\u00A0rocks\u00C2\u00A0and\u00C2\u00A0presence\u00C2\u00A0of\u00C2\u00A0pelagic\u00C2\u00A0sedimentary\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0Although\u00C2\u00A0not\u00C2\u00A0 unequivocal\u00C2\u00A0evidence\u00C2\u00A0of\u00C2\u00A0paleowater\u00C2\u00A0depth,\u00C2\u00A0a\u00C2\u00A0volcanic\u00C2\u00A0succession\u00C2\u00A0comprised\u00C2\u00A0entirely\u00C2\u00A0of\u00C2\u00A0massive\u00C2\u00A0 to\u00C2\u00A0pillowed\u00C2\u00A0lava\u00C2\u00A0flows\u00C2\u00A0and\u00C2\u00A0associated\u00C2\u00A0autoclastic\u00C2\u00A0deposits\u00C2\u00A0may\u00C2\u00A0be\u00C2\u00A0interpreted\u00C2\u00A0as\u00C2\u00A0a\u00C2\u00A0result\u00C2\u00A0of\u00C2\u00A0 deep\u00C2\u00A0water\u00C2\u00A0suppression\u00C2\u00A0of\u00C2\u00A0erupting\u00C2\u00A0lavas\u00C2\u00A0resulting\u00C2\u00A0in\u00C2\u00A0effusive\u00E2\u0080\u0090only\u00C2\u00A0eruptions\u00C2\u00A0(Cas,\u00C2\u00A01992;\u00C2\u00A0Batiza\u00C2\u00A0 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despite\u00C2\u00A0the\u00C2\u00A0inferred\u00C2\u00A0deep\u00C2\u00A0water\u00C2\u00A0setting\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0narrow\u00C2\u00A0rifted\u00C2\u00A0continental\u00C2\u00A0basin.\u00C2\u00A0\u00C2\u00A0With\u00C2\u00A0continental\u00C2\u00A0 topographic\u00C2\u00A0highs\u00C2\u00A0inferred\u00C2\u00A0at\u00C2\u00A0both\u00C2\u00A0margins,\u00C2\u00A0a\u00C2\u00A0greater\u00C2\u00A0proportion\u00C2\u00A0of\u00C2\u00A0sedimentary\u00C2\u00A0rocks\u00C2\u00A0might\u00C2\u00A0be\u00C2\u00A0 expected\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0deep\u00C2\u00A0basin,\u00C2\u00A0or\u00C2\u00A0at\u00C2\u00A0least\u00C2\u00A0close\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0margins\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0basin.\u00C2\u00A0\u00C2\u00A0Indeed,\u00C2\u00A0the\u00C2\u00A0San\u00C2\u00A0Pedro\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A047\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 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sequence\u00C2\u00A0temporally\u00C2\u00A0overlaps\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0entire\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0succession\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0western\u00C2\u00A0margin.\u00C2\u00A0\u00C2\u00A0 Clearly\u00C2\u00A0sedimentation\u00C2\u00A0was\u00C2\u00A0active\u00C2\u00A0during\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0episodes.\u00C2\u00A0\u00C2\u00A0Therefore,\u00C2\u00A0it\u00C2\u00A0is\u00C2\u00A0possible\u00C2\u00A0that\u00C2\u00A0the\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0represents\u00C2\u00A0an\u00C2\u00A0ocean\u00C2\u00A0ridge\u00E2\u0080\u0090type\u00C2\u00A0structure,\u00C2\u00A0analogous\u00C2\u00A0to\u00C2\u00A0back\u00E2\u0080\u0090arc\u00C2\u00A0 volcanic\u00C2\u00A0ridge\u00C2\u00A0edifices\u00C2\u00A0in\u00C2\u00A0modern\u00C2\u00A0settings.\u00C2\u00A0\u00C2\u00A0For\u00C2\u00A0comparison,\u00C2\u00A0the\u00C2\u00A0Manus\u00C2\u00A0Basin\u00C2\u00A0continental\u00C2\u00A0back\u00E2\u0080\u0090 arc\u00C2\u00A0rift\u00C2\u00A0hosts\u00C2\u00A0an\u00C2\u00A0active\u00C2\u00A0700\u00C2\u00A0m\u00E2\u0080\u0090high\u00C2\u00A0bimodal\u00C2\u00A0volcanic\u00C2\u00A0ridge\u00C2\u00A0flanked\u00C2\u00A0by\u00C2\u00A0siliciclastic\u00C2\u00A0rocks\u00C2\u00A0(Taylor\u00C2\u00A0et\u00C2\u00A0 al.,\u00C2\u00A01995).\u00C2\u00A0\u00C2\u00A0If\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0had\u00C2\u00A0been\u00C2\u00A0built\u00C2\u00A0as\u00C2\u00A0a\u00C2\u00A0topographically\u00C2\u00A0high\u00C2\u00A0volcanic\u00C2\u00A0 edifice,\u00C2\u00A0the\u00C2\u00A0interstratification\u00C2\u00A0of\u00C2\u00A0volcanic/volcaniclastic\u00C2\u00A0and\u00C2\u00A0sedimentary\u00C2\u00A0rocks\u00C2\u00A0may\u00C2\u00A0be\u00C2\u00A0limited\u00C2\u00A0to\u00C2\u00A0 the\u00C2\u00A0flanks\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0ridge.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 All\u00C2\u00A0known\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0prospects\u00C2\u00A0are\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 Formation,\u00C2\u00A0the\u00C2\u00A0lowermost\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0sequences\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0 Lorenzo\u00C2\u00A0Formation\u00C2\u00A0represents\u00C2\u00A0the\u00C2\u00A0initial\u00C2\u00A0magmatic\u00C2\u00A0pulse,\u00C2\u00A0or\u00C2\u00A0phase\u00C2\u00A01\u00C2\u00A0volcanic\u00C2\u00A0event,\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0rift\u00C2\u00A0 sequence\u00C2\u00A0and\u00C2\u00A0appears\u00C2\u00A0to\u00C2\u00A0have\u00C2\u00A0been\u00C2\u00A0deposited\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0relatively\u00C2\u00A0deep\u00C2\u00A0water\u00C2\u00A0environment\u00C2\u00A0during\u00C2\u00A0a\u00C2\u00A0 period\u00C2\u00A0of\u00C2\u00A0maximum\u00C2\u00A0subsidence.\u00C2\u00A0\u00C2\u00A0During\u00C2\u00A0phase\u00C2\u00A02\u00C2\u00A0volcanism,\u00C2\u00A0successions\u00C2\u00A0become\u00C2\u00A0progressively\u00C2\u00A0 more\u00C2\u00A0volcaniclastic\u00E2\u0080\u0090\u00C2\u00A0and\u00C2\u00A0sediment\u00E2\u0080\u0090rich\u00C2\u00A0and\u00C2\u00A0appear\u00C2\u00A0to\u00C2\u00A0have\u00C2\u00A0been\u00C2\u00A0deposited\u00C2\u00A0in\u00C2\u00A0relatively\u00C2\u00A0shallow\u00C2\u00A0 water\u00C2\u00A0as\u00C2\u00A0late\u00E2\u0080\u0090rift,\u00C2\u00A0basin\u00E2\u0080\u0090fill\u00C2\u00A0sequences.\u00C2\u00A0\u00C2\u00A0Therefore,\u00C2\u00A0the\u00C2\u00A0association\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0may\u00C2\u00A0be\u00C2\u00A0linked\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0establishment\u00C2\u00A0of\u00C2\u00A0large\u00E2\u0080\u0090scale\u00C2\u00A0hydrothermal\u00C2\u00A0 systems\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0early\u00E2\u0080\u0090rift\u00C2\u00A0tectonic\u00C2\u00A0stages,\u00C2\u00A0during\u00C2\u00A0the\u00C2\u00A0most\u00C2\u00A0likely\u00C2\u00A0period\u00C2\u00A0of\u00C2\u00A0high\u00C2\u00A0magma\u00C2\u00A0input,\u00C2\u00A0 maximum\u00C2\u00A0heat\u00C2\u00A0flow\u00C2\u00A0and\u00C2\u00A0high\u00C2\u00A0permeability\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0rift\u00E2\u0080\u0090related\u00C2\u00A0extensional\u00C2\u00A0and\u00C2\u00A0transcurrent\u00C2\u00A0 faulting.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0phase\u00C2\u00A02\u00C2\u00A0volcanic\u00C2\u00A0sequences\u00C2\u00A0have\u00C2\u00A0less\u00C2\u00A0potential\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0discovery\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0 and\u00C2\u00A0are\u00C2\u00A0not\u00C2\u00A0known\u00C2\u00A0to\u00C2\u00A0host\u00C2\u00A0any\u00C2\u00A0VMS\u00E2\u0080\u0090type\u00C2\u00A0mineral\u00C2\u00A0occurrences.\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A048\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 2.9.2\u00C2\u00A0 Timing\u00C2\u00A0and\u00C2\u00A0Duration\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Volcanic\u00C2\u00A0Arc\u00C2\u00A0 U\u00E2\u0080\u0090Pb\u00C2\u00A0TIMS\u00C2\u00A0and\u00C2\u00A0SHRIMP\u00E2\u0080\u0090RG\u00C2\u00A0zircon\u00C2\u00A0ages\u00C2\u00A0presented\u00C2\u00A0in\u00C2\u00A0this\u00C2\u00A0paper\u00C2\u00A0permit\u00C2\u00A0an\u00C2\u00A0estimation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 timing\u00C2\u00A0and\u00C2\u00A0duration\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0arc\u00C2\u00A0volcanism\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0(Fig.\u00C2\u00A02.12).\u00C2\u00A0\u00C2\u00A0Volcanism\u00C2\u00A0 commenced\u00C2\u00A0at\u00C2\u00A0a\u00C2\u00A0minimum\u00C2\u00A0of\u00C2\u00A0ca.\u00C2\u00A0105\u00C2\u00A0Ma\u00C2\u00A0(Albian)\u00C2\u00A0and\u00C2\u00A0continued\u00C2\u00A0to\u00C2\u00A0at\u00C2\u00A0least\u00C2\u00A0ca.\u00C2\u00A091\u00C2\u00A0Ma\u00C2\u00A0 (Turonian)\u00C2\u00A0suggesting\u00C2\u00A0a\u00C2\u00A0minimum\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0lifespan\u00C2\u00A0of\u00C2\u00A0~14\u00C2\u00A0Ma.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0upper\u00C2\u00A0age\u00C2\u00A0limit\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 volcanic\u00C2\u00A0succession\u00C2\u00A0is\u00C2\u00A0further\u00C2\u00A0constrained\u00C2\u00A0with\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0zircon\u00C2\u00A0ages\u00C2\u00A0of\u00C2\u00A078\u00E2\u0080\u009088\u00C2\u00A0Ma\u00C2\u00A0for\u00C2\u00A0granitic\u00C2\u00A0rocks\u00C2\u00A0 of\u00C2\u00A0the\u00C2\u00A0Coastal\u00C2\u00A0batholith\u00C2\u00A0that\u00C2\u00A0intruded\u00C2\u00A0into\u00C2\u00A0Lancones\u00C2\u00A0basin.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0the\u00C2\u00A0Ecuadorian\u00C2\u00A0segment\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 Lancones\u00C2\u00A0basin,\u00C2\u00A0granodiorite\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A0Los\u00C2\u00A0Linderos\u00C2\u00A0porphyry\u00C2\u00A0Cu\u00E2\u0080\u0090Mo\u00E2\u0080\u0090Au\u00C2\u00A0prospect\u00C2\u00A0(Chiaradia\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A0 2004)\u00C2\u00A0cuts\u00C2\u00A0basaltic\u00C2\u00A0rocks\u00C2\u00A0and\u00C2\u00A0is\u00C2\u00A0dated\u00C2\u00A0at\u00C2\u00A088.4\u00C2\u00A0\u00C2\u00B1\u00C2\u00A01.0\u00C2\u00A0Ma\u00C2\u00A0(Appendix\u00C2\u00A0B).\u00C2\u00A0\u00C2\u00A0Compared\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0youngest\u00C2\u00A0 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to\u00C2\u00A0dates\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation,\u00C2\u00A0ranges\u00C2\u00A0from\u00C2\u00A0a\u00C2\u00A0maximum\u00C2\u00A0age\u00C2\u00A0of\u00C2\u00A099.8\u00C2\u00A0\u00C2\u00B1\u00C2\u00A01.6\u00C2\u00A0Ma\u00C2\u00A0(sample\u00C2\u00A0 LW\u00E2\u0080\u0090086)\u00C2\u00A0to\u00C2\u00A0a\u00C2\u00A0lowermost\u00C2\u00A0age\u00C2\u00A0of\u00C2\u00A091.1\u00C2\u00A0\u00C2\u00B1\u00C2\u00A01.0\u00C2\u00A0Ma\u00C2\u00A0(LW\u00E2\u0080\u0090043)\u00C2\u00A0and\u00C2\u00A0suggests\u00C2\u00A0a\u00C2\u00A0minimum\u00C2\u00A0duration\u00C2\u00A0for\u00C2\u00A0 volcanism\u00C2\u00A0of\u00C2\u00A07\u00E2\u0080\u009010\u00C2\u00A0Ma.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 No\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation\u00C2\u00A0were\u00C2\u00A0suitable\u00C2\u00A0for\u00C2\u00A0dating\u00C2\u00A0methods\u00C2\u00A0employed\u00C2\u00A0in\u00C2\u00A0 this\u00C2\u00A0study,\u00C2\u00A0however,\u00C2\u00A0the\u00C2\u00A0approximate\u00C2\u00A0age\u00C2\u00A0range\u00C2\u00A0can\u00C2\u00A0be\u00C2\u00A0deduced\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0given\u00C2\u00A0ages\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 overlying\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0and\u00C2\u00A0underlying\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0(Fig.\u00C2\u00A02.15).\u00C2\u00A0\u00C2\u00A0 Volcanic\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation\u00C2\u00A0must\u00C2\u00A0be\u00C2\u00A0younger\u00C2\u00A0than\u00C2\u00A0100.2\u00C2\u00A0Ma.\u00C2\u00A0\u00C2\u00A0However,\u00C2\u00A0the\u00C2\u00A0 minimum\u00C2\u00A0age\u00C2\u00A0requires\u00C2\u00A0some\u00C2\u00A0consideration\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0stratigraphy\u00C2\u00A0and\u00C2\u00A0spatial\u00C2\u00A0distribution\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A049\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 various\u00C2\u00A0formations.\u00C2\u00A0\u00C2\u00A0Firstly,\u00C2\u00A0the\u00C2\u00A0oldest\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0occur\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0northern\u00C2\u00A0 part\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0map\u00C2\u00A0area\u00C2\u00A0and\u00C2\u00A0are\u00C2\u00A0dated\u00C2\u00A0at\u00C2\u00A099.3\u00C2\u00A0\u00C2\u00B1\u00C2\u00A00.3\u00C2\u00A0Ma.\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0values\u00C2\u00A0suggest\u00C2\u00A0a\u00C2\u00A0potential\u00C2\u00A00\u00E2\u0080\u00903\u00C2\u00A0Ma\u00C2\u00A0 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complex,\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0is\u00C2\u00A0known\u00C2\u00A0to\u00C2\u00A0be\u00C2\u00A0conformable\u00C2\u00A0above\u00C2\u00A0the\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation.\u00C2\u00A0\u00C2\u00A0 Age\u00C2\u00A0constraints\u00C2\u00A0in\u00C2\u00A0this\u00C2\u00A0part\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0are\u00C2\u00A0much\u00C2\u00A0younger\u00C2\u00A0(91.1\u00C2\u00A0\u00C2\u00B1\u00C2\u00A01.0\u00C2\u00A0Ma)\u00C2\u00A0 indicating\u00C2\u00A0a\u00C2\u00A0time\u00C2\u00A0interval\u00C2\u00A0than\u00C2\u00A0spans\u00C2\u00A0at\u00C2\u00A0least\u00C2\u00A0~8\u00E2\u0080\u009011\u00C2\u00A0Ma\u00C2\u00A0for\u00C2\u00A0duration\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 and\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0formations.\u00C2\u00A0\u00C2\u00A0Under\u00C2\u00A0this\u00C2\u00A0scenario\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0southern\u00C2\u00A0Lancones\u00C2\u00A0Basin,\u00C2\u00A0the\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0 Formation\u00C2\u00A0would\u00C2\u00A0have\u00C2\u00A0potentially\u00C2\u00A0been\u00C2\u00A0deposited\u00C2\u00A0contemporaneously\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0deposition\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0lower\u00C2\u00A0part\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0north.\u00C2\u00A0\u00C2\u00A0Due\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0monotonous\u00C2\u00A0basaltic\u00C2\u00A0 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Winter\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(2004)\u00C2\u00A0provide\u00C2\u00A0a\u00C2\u00A0detailed\u00C2\u00A0reconstruction\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0TG1\u00C2\u00A0and\u00C2\u00A0TG3\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0 whereby\u00C2\u00A0equivalent\u00C2\u00A0time\u00E2\u0080\u0090stratigraphic\u00C2\u00A0horizons\u00C2\u00A0can\u00C2\u00A0be\u00C2\u00A0correlated\u00C2\u00A0between\u00C2\u00A0each\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0TG1\u00C2\u00A0and\u00C2\u00A0 TG3\u00C2\u00A0deposits.\u00C2\u00A0\u00C2\u00A0Therefore,\u00C2\u00A0the\u00C2\u00A0relative\u00C2\u00A0timing\u00C2\u00A0of\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0formation\u00C2\u00A0for\u00C2\u00A0these\u00C2\u00A0deposits\u00C2\u00A0is\u00C2\u00A0 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eruption\u00C2\u00A0was\u00C2\u00A0most\u00C2\u00A0likely\u00C2\u00A0synchronous\u00C2\u00A0with\u00C2\u00A0or\u00C2\u00A0slightly\u00C2\u00A0post\u00E2\u0080\u0090dates\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0formation.\u00C2\u00A0\u00C2\u00A0 Additional\u00C2\u00A0age\u00C2\u00A0constraints\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0deposits\u00C2\u00A0are\u00C2\u00A0thus\u00C2\u00A0provided\u00C2\u00A0by\u00C2\u00A0a\u00C2\u00A0rhyolite\u00C2\u00A0dyke\u00C2\u00A0that\u00C2\u00A0intrudes\u00C2\u00A0 the\u00C2\u00A0TG1\u00C2\u00A0deposit.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0felsic\u00C2\u00A0unit\u00C2\u00A0represents\u00C2\u00A0a\u00C2\u00A0post\u00E2\u0080\u0090mineralization\u00C2\u00A0phase\u00C2\u00A0and\u00C2\u00A0provides\u00C2\u00A0a\u00C2\u00A0 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Comparison\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0Western\u00C2\u00A0Peruvian\u00C2\u00A0Trough\u00C2\u00A0 Geochronologic\u00C2\u00A0and\u00C2\u00A0stratigraphic\u00C2\u00A0data\u00C2\u00A0presented\u00C2\u00A0herein\u00C2\u00A0verify\u00C2\u00A0the\u00C2\u00A0broadly\u00C2\u00A0 contemporaneous\u00C2\u00A0evolution\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0successions\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0and\u00C2\u00A0Western\u00C2\u00A0 Peruvian\u00C2\u00A0Trough.\u00C2\u00A0\u00C2\u00A0Stratigraphically,\u00C2\u00A0the\u00C2\u00A0Casma\u00C2\u00A0group\u00C2\u00A0that\u00C2\u00A0filled\u00C2\u00A0the\u00C2\u00A0Western\u00C2\u00A0Peruvian\u00C2\u00A0Trough\u00C2\u00A0 has\u00C2\u00A0a\u00C2\u00A0total\u00C2\u00A0thickness\u00C2\u00A0of\u00C2\u00A0up\u00C2\u00A0to\u00C2\u00A09\u00C2\u00A0km\u00C2\u00A0and\u00C2\u00A0is\u00C2\u00A0dominated\u00C2\u00A0by\u00C2\u00A0mafic\u00C2\u00A0with\u00C2\u00A0lesser\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0 (Myers,\u00C2\u00A01974;\u00C2\u00A0Cobbing\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01981;\u00C2\u00A0Offler\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01980;\u00C2\u00A0Soler\u00C2\u00A0and\u00C2\u00A0Bonhomme,\u00C2\u00A01990),\u00C2\u00A0comparable\u00C2\u00A0 to\u00C2\u00A0the\u00C2\u00A08\u00E2\u0080\u009010\u00C2\u00A0km\u00C2\u00A0of\u00C2\u00A0mafic\u00E2\u0080\u0090dominated\u00C2\u00A0bimodal\u00C2\u00A0strata\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0(Fig.\u00C2\u00A02.16).\u00C2\u00A0\u00C2\u00A0Volcanism\u00C2\u00A0 recorded\u00C2\u00A0by\u00C2\u00A0the\u00C2\u00A0Casma\u00C2\u00A0Group\u00C2\u00A0was\u00C2\u00A0largely\u00C2\u00A0terminated\u00C2\u00A0during\u00C2\u00A0the\u00C2\u00A0late\u00C2\u00A0Albian\u00E2\u0080\u0090Early\u00C2\u00A0Cenomanian\u00C2\u00A0 indicating\u00C2\u00A0a\u00C2\u00A0short\u00E2\u0080\u0090lived\u00C2\u00A0but\u00C2\u00A0vigorous\u00C2\u00A0volcanic\u00C2\u00A0event.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0Mochica\u00C2\u00A0phase,\u00C2\u00A0which\u00C2\u00A0represents\u00C2\u00A0the\u00C2\u00A0first\u00C2\u00A0contractional\u00C2\u00A0orogeny\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0central\u00C2\u00A0Peruvian\u00C2\u00A0 Andes\u00C2\u00A0(M\u00C3\u00A9gard,\u00C2\u00A01984),\u00C2\u00A0affected\u00C2\u00A0the\u00C2\u00A0Casma\u00C2\u00A0Group\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A0Albian\u00E2\u0080\u0090Cenomanian\u00C2\u00A0boundary.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0 effectively\u00C2\u00A0represents\u00C2\u00A0the\u00C2\u00A0termination\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0rift\u00E2\u0080\u0090stage\u00C2\u00A0marine\u00C2\u00A0volcanism.\u00C2\u00A0\u00C2\u00A0Volcanic\u00C2\u00A0rocks\u00C2\u00A0post\u00E2\u0080\u0090 dating\u00C2\u00A0the\u00C2\u00A0Mochica\u00C2\u00A0phase\u00C2\u00A0were\u00C2\u00A0interpreted\u00C2\u00A0to\u00C2\u00A0be\u00C2\u00A0as\u00C2\u00A0the\u00C2\u00A0products\u00C2\u00A0of\u00C2\u00A0shallow\u00C2\u00A0marine\u00C2\u00A0to\u00C2\u00A0subaerial\u00C2\u00A0 volcanism\u00C2\u00A0(Webb\u00C2\u00A0in\u00C2\u00A0Cobbing\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01981)\u00C2\u00A0and\u00C2\u00A0these\u00C2\u00A0eruptions\u00C2\u00A0overlapped\u00C2\u00A0the\u00C2\u00A0initial\u00C2\u00A0phases\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0Coastal\u00C2\u00A0Batholith\u00C2\u00A0(Soler\u00C2\u00A0and\u00C2\u00A0Bonhomme,\u00C2\u00A01990).\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0marine\u00C2\u00A0transgression\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0deposition\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A051\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 of\u00C2\u00A0shelf\u00C2\u00A0carbonates\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Western\u00C2\u00A0Peruvian\u00C2\u00A0Trough\u00C2\u00A0are\u00C2\u00A0recorded\u00C2\u00A0during\u00C2\u00A0Cenomanian\u00C2\u00A0to\u00C2\u00A0 Turonian\u00C2\u00A0times\u00C2\u00A0(Jaillard\u00C2\u00A0and\u00C2\u00A0Soler,\u00C2\u00A01996).\u00C2\u00A0\u00C2\u00A0Although\u00C2\u00A0deformation\u00C2\u00A0related\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0Mochica\u00C2\u00A0 orogeny\u00C2\u00A0is\u00C2\u00A0not\u00C2\u00A0well\u00C2\u00A0documented\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin,\u00C2\u00A0the\u00C2\u00A0timing\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 contractional\u00C2\u00A0episode\u00C2\u00A0coincides\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0transition\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0to\u00C2\u00A0La\u00C2\u00A0 Bocana\u00C2\u00A0Formation.\u00C2\u00A0\u00C2\u00A0Moreover,\u00C2\u00A0the\u00C2\u00A0facies\u00C2\u00A0change\u00C2\u00A0from\u00C2\u00A0deep(?)\u00C2\u00A0water,\u00C2\u00A0pillow\u00C2\u00A0lava\u00E2\u0080\u0090dominated\u00C2\u00A0 volcanic\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0to\u00C2\u00A0mixed\u00C2\u00A0pyroclastic,\u00C2\u00A0siliciclastic\u00C2\u00A0and\u00C2\u00A0 carbonate\u00C2\u00A0rocks,\u00C2\u00A0representing\u00C2\u00A0dominantly\u00C2\u00A0shallow\u00C2\u00A0water\u00C2\u00A0environments,\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0 Formation\u00C2\u00A0and\u00C2\u00A0younger\u00C2\u00A0sequences\u00C2\u00A0suggests\u00C2\u00A0a\u00C2\u00A0major\u00C2\u00A0geodynamic\u00C2\u00A0change,\u00C2\u00A0the\u00C2\u00A0timing\u00C2\u00A0of\u00C2\u00A0which\u00C2\u00A0is\u00C2\u00A0 similar\u00C2\u00A0to\u00C2\u00A0that\u00C2\u00A0described\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0upper\u00C2\u00A0Casma\u00C2\u00A0Group.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0stratigraphic\u00C2\u00A0thickness,\u00C2\u00A0relative\u00C2\u00A0age,\u00C2\u00A0 volcanic\u00C2\u00A0facies\u00C2\u00A0and\u00C2\u00A0inferred\u00C2\u00A0depositional\u00C2\u00A0environment\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Western\u00C2\u00A0Peruvian\u00C2\u00A0Trough\u00C2\u00A0is\u00C2\u00A0 remarkably\u00C2\u00A0similar\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0and\u00C2\u00A0suggests\u00C2\u00A0that\u00C2\u00A0both\u00C2\u00A0basins\u00C2\u00A0evolved\u00C2\u00A0along\u00C2\u00A0nearly\u00C2\u00A0 identical\u00C2\u00A0pathways.\u00C2\u00A0 2.9.5\u00C2\u00A0 Tectonic\u00C2\u00A0Implications\u00C2\u00A0 The\u00C2\u00A0fundamental\u00C2\u00A0processes\u00C2\u00A0required\u00C2\u00A0to\u00C2\u00A0generate\u00C2\u00A0a\u00C2\u00A0marginal\u00C2\u00A0rift\u00C2\u00A0basin\u00C2\u00A0related\u00C2\u00A0to\u00C2\u00A0subduction\u00C2\u00A0 along\u00C2\u00A0a\u00C2\u00A0continental\u00C2\u00A0margin\u00C2\u00A0are\u00C2\u00A0considered\u00C2\u00A0to\u00C2\u00A0be\u00C2\u00A0fairly\u00C2\u00A0well\u00C2\u00A0understood\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0prerequisites\u00C2\u00A0 being\u00C2\u00A0a\u00C2\u00A0subducting\u00C2\u00A0and\u00C2\u00A0\u00E2\u0080\u0098sinking\u00E2\u0080\u0099\u00C2\u00A0ocean\u00C2\u00A0slab\u00C2\u00A0and\u00C2\u00A0a\u00C2\u00A0trench\u00C2\u00A0line\u00C2\u00A0that\u00C2\u00A0migrates\u00C2\u00A0oceanwards\u00C2\u00A0at\u00C2\u00A0a\u00C2\u00A0 greater\u00C2\u00A0rate\u00C2\u00A0than\u00C2\u00A0the\u00C2\u00A0overriding\u00C2\u00A0plate,\u00C2\u00A0termed\u00C2\u00A0slab\u00C2\u00A0\u00E2\u0080\u0098rollback\u00E2\u0080\u0099\u00C2\u00A0(Hamilton,\u00C2\u00A01995).\u00C2\u00A0\u00C2\u00A0Benavides\u00E2\u0080\u0090 C\u00C3\u00A1ceres\u00C2\u00A0(1999)\u00C2\u00A0suggests\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0marginal\u00C2\u00A0rift\u00C2\u00A0resembled\u00C2\u00A0a\u00C2\u00A0\u00E2\u0080\u0098Mariana\u00E2\u0080\u0090type\u00E2\u0080\u0099\u00C2\u00A0arc\u00C2\u00A0(Karig\u00C2\u00A0 et\u00C2\u00A0al.,\u00C2\u00A01978)\u00C2\u00A0which\u00C2\u00A0forms\u00C2\u00A0when\u00C2\u00A0the\u00C2\u00A0overriding\u00C2\u00A0plate,\u00C2\u00A0either\u00C2\u00A0oceanic\u00C2\u00A0or\u00C2\u00A0continental,\u00C2\u00A0is\u00C2\u00A0attenuated\u00C2\u00A0 and\u00C2\u00A0rifted\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0tensional\u00C2\u00A0stresses\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0a\u00C2\u00A0steeply\u00C2\u00A0dipping\u00C2\u00A0slab,\u00C2\u00A0rollback\u00C2\u00A0and\u00C2\u00A0arc\u00C2\u00A0 migration.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0stratigraphic\u00C2\u00A0and\u00C2\u00A0geochronologic\u00C2\u00A0data\u00C2\u00A0in\u00C2\u00A0this\u00C2\u00A0study\u00C2\u00A0help\u00C2\u00A0to\u00C2\u00A0reconcile\u00C2\u00A0the\u00C2\u00A0 tectonic\u00C2\u00A0regime\u00C2\u00A0related\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0formation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0and,\u00C2\u00A0by\u00C2\u00A0inference,\u00C2\u00A0the\u00C2\u00A0Western\u00C2\u00A0 Peruvian\u00C2\u00A0Trough.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A052\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 The\u00C2\u00A0formation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Western\u00C2\u00A0Peruvian\u00C2\u00A0Trough\u00C2\u00A0is\u00C2\u00A0temporally\u00C2\u00A0linked\u00C2\u00A0with\u00C2\u00A0a\u00C2\u00A0major\u00C2\u00A0global\u00C2\u00A0 tectonic\u00C2\u00A0event,\u00C2\u00A0the\u00C2\u00A0final\u00C2\u00A0break\u00E2\u0080\u0090up\u00C2\u00A0of\u00C2\u00A0Gondwana,\u00C2\u00A0which\u00C2\u00A0culminated\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0opening\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0South\u00C2\u00A0 Atlantic\u00C2\u00A0Ocean\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Early\u00C2\u00A0Cretaceous\u00C2\u00A0(Scotese,\u00C2\u00A01991).\u00C2\u00A0\u00C2\u00A0More\u00C2\u00A0specifically,\u00C2\u00A0the\u00C2\u00A0Albian\u00C2\u00A0represents\u00C2\u00A0 the\u00C2\u00A0time\u00C2\u00A0of\u00C2\u00A0final\u00C2\u00A0separation\u00C2\u00A0of\u00C2\u00A0South\u00C2\u00A0America\u00C2\u00A0from\u00C2\u00A0Africa\u00C2\u00A0and\u00C2\u00A0opening\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0equatorial\u00C2\u00A0South\u00C2\u00A0 Atlantic\u00C2\u00A0ca.\u00C2\u00A0105\u00C2\u00A0Ma\u00C2\u00A0(Sibuet\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01984;\u00C2\u00A0Scotese,\u00C2\u00A01991).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0lack\u00C2\u00A0of\u00C2\u00A0significant\u00C2\u00A0westward\u00C2\u00A0motion\u00C2\u00A0 of\u00C2\u00A0the\u00C2\u00A0South\u00C2\u00A0America\u00C2\u00A0plate\u00C2\u00A0during\u00C2\u00A0the\u00C2\u00A0Albian\u00C2\u00A0was\u00C2\u00A0of\u00C2\u00A0major\u00C2\u00A0importance\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0formation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 Western\u00C2\u00A0Peruvian\u00C2\u00A0Trough\u00C2\u00A0and\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0as\u00C2\u00A0a\u00C2\u00A0steeply\u00C2\u00A0subducting\u00C2\u00A0but\u00C2\u00A0retreating\u00C2\u00A0oceanic\u00C2\u00A0 slab\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0Pacific\u00C2\u00A0margin\u00C2\u00A0of\u00C2\u00A0South\u00C2\u00A0America\u00C2\u00A0triggered\u00C2\u00A0oceanwards\u00C2\u00A0(westwards)\u00C2\u00A0migration\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0overlying\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0(Soler\u00C2\u00A0and\u00C2\u00A0Bonhomme,\u00C2\u00A01990).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0result\u00C2\u00A0was\u00C2\u00A0extension\u00C2\u00A0and\u00C2\u00A0rifting\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0overlying\u00C2\u00A0western\u00C2\u00A0continental\u00C2\u00A0margin\u00C2\u00A0of\u00C2\u00A0South\u00C2\u00A0America\u00C2\u00A0and\u00C2\u00A0subsequent\u00C2\u00A0arc\u00C2\u00A0volcanism\u00C2\u00A0 leading\u00C2\u00A0to\u00C2\u00A0a\u00C2\u00A0paleogeography\u00C2\u00A0that\u00C2\u00A0may\u00C2\u00A0have\u00C2\u00A0resembled\u00C2\u00A0the\u00C2\u00A0modern\u00C2\u00A0day\u00C2\u00A0Bransfield\u00C2\u00A0Strait\u00C2\u00A0(Barker\u00C2\u00A0 and\u00C2\u00A0Austin,\u00C2\u00A01998)\u00C2\u00A0or\u00C2\u00A0the\u00C2\u00A0Miocene\u00C2\u00A0Japan\u00C2\u00A0Sea\u00C2\u00A0(Jolivet\u00C2\u00A0and\u00C2\u00A0Tamaki,\u00C2\u00A01992).\u00C2\u00A0\u00C2\u00A0With\u00C2\u00A0the\u00C2\u00A0onset\u00C2\u00A0of\u00C2\u00A0 spreading\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0South\u00C2\u00A0Atlantic\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0westward\u00C2\u00A0drift\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0South\u00C2\u00A0American\u00C2\u00A0continent,\u00C2\u00A0the\u00C2\u00A0 development\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0and\u00C2\u00A0Western\u00C2\u00A0Peruvian\u00C2\u00A0Trough\u00C2\u00A0terminated\u00C2\u00A0(Soler\u00C2\u00A0and\u00C2\u00A0 Bonhomme,\u00C2\u00A01990).\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0transition\u00C2\u00A0from\u00C2\u00A0extensional\u00C2\u00A0to\u00C2\u00A0contractional\u00C2\u00A0tectonics\u00C2\u00A0is\u00C2\u00A0marked\u00C2\u00A0by\u00C2\u00A0the\u00C2\u00A0 Mochica\u00C2\u00A0Orogeny\u00C2\u00A0(M\u00C3\u00A9gard,\u00C2\u00A01984).\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin,\u00C2\u00A0shallow\u00C2\u00A0marine\u00C2\u00A0to\u00C2\u00A0terrestrial\u00C2\u00A0 volcanism\u00C2\u00A0of\u00C2\u00A0phase\u00C2\u00A02\u00C2\u00A0followed\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0less\u00C2\u00A0extended\u00C2\u00A0margin\u00C2\u00A0and\u00C2\u00A0evolved\u00C2\u00A0to\u00C2\u00A0granitoid\u00C2\u00A0plutonism\u00C2\u00A0 under\u00C2\u00A0a\u00C2\u00A0continental\u00C2\u00A0arc\u00C2\u00A0regime.\u00C2\u00A0 2.9.6\u00C2\u00A0 Inheritance\u00C2\u00A0in\u00C2\u00A0Zircons\u00C2\u00A0and\u00C2\u00A0Implications\u00C2\u00A0for\u00C2\u00A0Basement\u00C2\u00A0Rocks\u00C2\u00A0 \u00C2\u00A0 Only\u00C2\u00A0minor\u00C2\u00A0inheritance\u00C2\u00A0is\u00C2\u00A0suggested\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0zircon\u00C2\u00A0data\u00C2\u00A0from\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0 Lorenzo\u00C2\u00A0Formation\u00C2\u00A0but\u00C2\u00A0significantly\u00C2\u00A0more\u00C2\u00A0inheritance\u00C2\u00A0is\u00C2\u00A0obvious\u00C2\u00A0from\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0 Bocana\u00C2\u00A0Formation.\u00C2\u00A0\u00C2\u00A0Although\u00C2\u00A0there\u00C2\u00A0is\u00C2\u00A0somewhat\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0sampling\u00C2\u00A0bias\u00C2\u00A0with\u00C2\u00A0more\u00C2\u00A0samples\u00C2\u00A0collected\u00C2\u00A0 from\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0than\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation,\u00C2\u00A0the\u00C2\u00A0greater\u00C2\u00A0 inheritance\u00C2\u00A0of\u00C2\u00A0zircon\u00C2\u00A0by\u00C2\u00A0felsic\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0may\u00C2\u00A0indicate\u00C2\u00A0a\u00C2\u00A0more\u00C2\u00A0important\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A053\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 continental\u00C2\u00A0crust\u00C2\u00A0component\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0source\u00C2\u00A0and/or\u00C2\u00A0pathways\u00C2\u00A0of\u00C2\u00A0these\u00C2\u00A0lavas.\u00C2\u00A0\u00C2\u00A0Three\u00C2\u00A0of\u00C2\u00A0ten\u00C2\u00A0 samples\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0display\u00C2\u00A0a\u00C2\u00A0variety\u00C2\u00A0of\u00C2\u00A0inherited\u00C2\u00A0ages\u00C2\u00A0up\u00C2\u00A0to\u00C2\u00A02,500\u00C2\u00A0Ma.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0 strong\u00C2\u00A0inheritance\u00C2\u00A0implicates\u00C2\u00A0continental\u00C2\u00A0crust\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0genesis\u00C2\u00A0of\u00C2\u00A0these\u00C2\u00A0rocks,\u00C2\u00A0especially\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0 younger\u00C2\u00A0sequences.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0concept\u00C2\u00A0has\u00C2\u00A0implications\u00C2\u00A0for\u00C2\u00A0basement\u00C2\u00A0development\u00C2\u00A0and\u00C2\u00A0magma\u00C2\u00A0 genesis\u00C2\u00A0and\u00C2\u00A0is\u00C2\u00A0explored\u00C2\u00A0in\u00C2\u00A0greater\u00C2\u00A0detail\u00C2\u00A0elsewhere\u00C2\u00A0(Chapter\u00C2\u00A05).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 2.10\u00C2\u00A0 Conclusions\u00C2\u00A0 The\u00C2\u00A0depositional\u00C2\u00A0history\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0is\u00C2\u00A0recorded\u00C2\u00A0by\u00C2\u00A0a\u00C2\u00A0~10\u00C2\u00A0km\u00C2\u00A0sequence\u00C2\u00A0of\u00C2\u00A0 bimodal\u00C2\u00A0volcanic\u00C2\u00A0and\u00C2\u00A0volcaniclastic\u00C2\u00A0rocks\u00C2\u00A0representing\u00C2\u00A0at\u00C2\u00A0least\u00C2\u00A0~14\u00C2\u00A0Ma\u00C2\u00A0of\u00C2\u00A0volcanic\u00C2\u00A0activity\u00C2\u00A0from\u00C2\u00A0 ca.\u00C2\u00A0105\u00C2\u00A0Ma\u00C2\u00A0to\u00C2\u00A0ca.\u00C2\u00A091\u00C2\u00A0Ma\u00C2\u00A0based\u00C2\u00A0on\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0zircon\u00C2\u00A0ages.\u00C2\u00A0\u00C2\u00A0Two\u00C2\u00A0main\u00C2\u00A0phases\u00C2\u00A0of\u00C2\u00A0volcanism\u00C2\u00A0comprise\u00C2\u00A0 the\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0sequence:\u00C2\u00A0(i)\u00C2\u00A0Phase\u00C2\u00A01\u00C2\u00A0volcanism,\u00C2\u00A0recorded\u00C2\u00A0by\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation,\u00C2\u00A0 represents\u00C2\u00A0deep\u00E2\u0080\u0090water,\u00C2\u00A0bimodal,\u00C2\u00A0mafic\u00E2\u0080\u0090dominated\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0comprised\u00C2\u00A0of\u00C2\u00A0lava\u00C2\u00A0flows,\u00C2\u00A0 autoclastic\u00C2\u00A0breccias\u00C2\u00A0and\u00C2\u00A0minor\u00C2\u00A0pelagic\u00C2\u00A0sedimentary\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0Four\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0zircon\u00C2\u00A0ages\u00C2\u00A0ranging\u00C2\u00A0from\u00C2\u00A0 104.8\u00C2\u00A0\u00C2\u00B11.3\u00C2\u00A0to\u00C2\u00A0100.2\u00C2\u00A0\u00C2\u00B10.5\u00C2\u00A0Ma\u00C2\u00A0suggest\u00C2\u00A0middle\u00C2\u00A0to\u00C2\u00A0late\u00C2\u00A0Albian\u00C2\u00A0ages\u00C2\u00A0for\u00C2\u00A0this\u00C2\u00A0formation.\u00C2\u00A0\u00C2\u00A0VMS\u00C2\u00A0 deposits\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0are\u00C2\u00A0hosted\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0and\u00C2\u00A0have\u00C2\u00A0a\u00C2\u00A0 minimum\u00C2\u00A0age\u00C2\u00A0of\u00C2\u00A0104.8\u00C2\u00A0\u00C2\u00B11.3\u00C2\u00A0Ma,\u00C2\u00A0as\u00C2\u00A0constrained\u00C2\u00A0by\u00C2\u00A0the\u00C2\u00A0pre\u00E2\u0080\u0090syn\u00C2\u00A0mineralization\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0 rocks.\u00C2\u00A0\u00C2\u00A0Pre\u00E2\u0080\u0090mineralization\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0did\u00C2\u00A0not\u00C2\u00A0yield\u00C2\u00A0any\u00C2\u00A0minerals\u00C2\u00A0suitable\u00C2\u00A0to\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0dating\u00C2\u00A0 methods.\u00C2\u00A0\u00C2\u00A0(ii)\u00C2\u00A0Phase\u00C2\u00A02\u00C2\u00A0volcanism\u00C2\u00A0is\u00C2\u00A0recorded\u00C2\u00A0by\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0El\u00C2\u00A0Ereo,\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0and\u00C2\u00A0Lancones\u00C2\u00A0 Formations.\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0formations\u00C2\u00A0are\u00C2\u00A0dominated\u00C2\u00A0by\u00C2\u00A0deposits\u00C2\u00A0of\u00C2\u00A0shallow\u00C2\u00A0marine\u00C2\u00A0facies\u00C2\u00A0and\u00C2\u00A0\u00C2\u00A0are\u00C2\u00A0 represented\u00C2\u00A0by\u00C2\u00A0bimodal\u00C2\u00A0volcanism.\u00C2\u00A0\u00C2\u00A0Five\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0zircon\u00C2\u00A0ages\u00C2\u00A0range\u00C2\u00A0from\u00C2\u00A099.3\u00C2\u00A0\u00C2\u00B10.3\u00C2\u00A0to\u00C2\u00A091.1\u00C2\u00A0\u00C2\u00B11.0\u00C2\u00A0Ma.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0volcanic\u00C2\u00A0phases\u00C2\u00A0are\u00C2\u00A0broadly\u00C2\u00A0chronologically\u00C2\u00A0correlated\u00C2\u00A0with\u00C2\u00A0major\u00C2\u00A0tectonomagmatic\u00C2\u00A0 events,\u00C2\u00A0specifically\u00C2\u00A0the\u00C2\u00A0opening\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0South\u00C2\u00A0Atlantic\u00C2\u00A0Ocean\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Early\u00C2\u00A0Cretaceous\u00C2\u00A0during\u00C2\u00A0the\u00C2\u00A0 final\u00C2\u00A0break\u00E2\u0080\u0090up\u00C2\u00A0of\u00C2\u00A0Gondwana.\u00C2\u00A0\u00C2\u00A0Phase\u00C2\u00A01\u00C2\u00A0volcanism\u00C2\u00A0was\u00C2\u00A0a\u00C2\u00A0result\u00C2\u00A0of\u00C2\u00A0strong\u00C2\u00A0crustal\u00C2\u00A0attenuation\u00C2\u00A0and\u00C2\u00A0 rifting\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0western\u00C2\u00A0margin\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0relatively\u00C2\u00A0static\u00C2\u00A0South\u00C2\u00A0American\u00C2\u00A0continent\u00C2\u00A0during\u00C2\u00A0Albian\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A054\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 times.\u00C2\u00A0\u00C2\u00A0Phase\u00C2\u00A01\u00C2\u00A0correlates\u00C2\u00A0with\u00C2\u00A0pre\u00E2\u0080\u0090opening\u00C2\u00A0or\u00C2\u00A0rift\u00C2\u00A0stage\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0South\u00C2\u00A0Atlantic\u00C2\u00A0at\u00C2\u00A0equatorial\u00C2\u00A0 latitudes.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0during\u00C2\u00A0phase\u00C2\u00A01\u00C2\u00A0volcanism\u00C2\u00A0would\u00C2\u00A0have\u00C2\u00A0resembled\u00C2\u00A0a\u00C2\u00A0modern\u00C2\u00A0day\u00C2\u00A0 back\u00E2\u0080\u0090arc\u00C2\u00A0basin\u00C2\u00A0or\u00C2\u00A0rifted\u00C2\u00A0arc\u00E2\u0080\u0090type\u00C2\u00A0setting.\u00C2\u00A0\u00C2\u00A0Active\u00C2\u00A0spreading\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0South\u00C2\u00A0Atlantic\u00C2\u00A0Ocean\u00C2\u00A0and\u00C2\u00A0 westward\u00C2\u00A0drift\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0South\u00C2\u00A0American\u00C2\u00A0continent\u00C2\u00A0correlates\u00C2\u00A0broadly\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0Mochica\u00C2\u00A0orogeny\u00C2\u00A0in\u00C2\u00A0 the\u00C2\u00A0western\u00C2\u00A0Andes\u00C2\u00A0during\u00C2\u00A0Albian\u00C2\u00A0times.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0contractional\u00C2\u00A0tectonic\u00C2\u00A0event\u00C2\u00A0marks\u00C2\u00A0the\u00C2\u00A0 termination\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0phase\u00C2\u00A01\u00C2\u00A0volcanic\u00C2\u00A0event.\u00C2\u00A0\u00C2\u00A0Phase\u00C2\u00A02\u00C2\u00A0volcanism\u00C2\u00A0is\u00C2\u00A0more\u00C2\u00A0typical\u00C2\u00A0of\u00C2\u00A0 Andean\u00C2\u00A0arc\u00C2\u00A0magmatism\u00C2\u00A0and\u00C2\u00A0was\u00C2\u00A0the\u00C2\u00A0result\u00C2\u00A0of\u00C2\u00A0subduction\u00C2\u00A0beneath\u00C2\u00A0a\u00C2\u00A0less\u00C2\u00A0extensional\u00C2\u00A0margin\u00C2\u00A0 during\u00C2\u00A0late\u00C2\u00A0Albian\u00C2\u00A0to\u00C2\u00A0Turonian\u00C2\u00A0times.\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A055\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A02.1.\u00C2\u00A0\u00C2\u00A0Morphostructural\u00C2\u00A0units\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Peruvian\u00C2\u00A0Andes\u00C2\u00A0(modified\u00C2\u00A0after\u00C2\u00A0Benavides\u00E2\u0080\u0090C\u00C3\u00A1ceres,\u00C2\u00A0 1999).\u00C2\u00A0\u00C2\u00A0Cretaceous\u00C2\u00A0marginal\u00C2\u00A0basins\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0Lancones\u00C2\u00A0(LB),\u00C2\u00A0Huarmey\u00C2\u00A0(HB)\u00C2\u00A0and\u00C2\u00A0Ca\u00C3\u00B1ete\u00C2\u00A0(CB)\u00C2\u00A0basins\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0are\u00C2\u00A0 superimposed.\u00C2\u00A0\u00C2\u00A0Also\u00C2\u00A0shown\u00C2\u00A0are\u00C2\u00A0the\u00C2\u00A0locations\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0prospects\u00C2\u00A0(circles)\u00C2\u00A0(data\u00C2\u00A0from\u00C2\u00A0 Steinm\u00C3\u00BCller\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02000).\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A056\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A02.2.\u00C2\u00A0\u00C2\u00A0A.\u00C2\u00A0Location\u00C2\u00A0map\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0Tambogrande\u00C2\u00A0project;\u00C2\u00A0B.\u00C2\u00A0regional\u00C2\u00A0map\u00C2\u00A0showing\u00C2\u00A0major\u00C2\u00A0 tectonostratigraphic\u00C2\u00A0units\u00C2\u00A0of\u00C2\u00A0coastal\u00C2\u00A0northwestern\u00C2\u00A0Per\u00C3\u00BA.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0locations\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0(TG1,\u00C2\u00A0 TG3,\u00C2\u00A0and\u00C2\u00A0B5)\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Tambogrande\u00C2\u00A0area\u00C2\u00A0are\u00C2\u00A0also\u00C2\u00A0shown\u00C2\u00A0and\u00C2\u00A0field\u00C2\u00A0area\u00C2\u00A0of\u00C2\u00A0this\u00C2\u00A0study\u00C2\u00A0outlined.\u00C2\u00A0\u00C2\u00A0 Modified\u00C2\u00A0after\u00C2\u00A0Jaillard\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1999)\u00C2\u00A0and\u00C2\u00A0Tegart\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(2000).\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A057\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Table\u00C2\u00A02.1.\u00C2\u00A0\u00C2\u00A0Summary\u00C2\u00A0of\u00C2\u00A0location\u00C2\u00A0and\u00C2\u00A0description\u00C2\u00A0data\u00C2\u00A0for\u00C2\u00A0samples\u00C2\u00A0analyzed\u00C2\u00A0in\u00C2\u00A0this\u00C2\u00A0study\u00C2\u00A0for\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0zircon\u00C2\u00A0dating.\u00C2\u00A0 Sample\u00C2\u00A0ID\u00C2\u00A0 UTM\u00C2\u00A0 Easting\u00C2\u00A0 UTM\u00C2\u00A0 Westing\u00C2\u00A0 Calculated\u00C2\u00A0 age\u00C2\u00A0+/\u00E2\u0080\u0090\u00C2\u00A0 error\u00C2\u00A0(Ma)\u00C2\u00A0 Description\u00C2\u00A0 Analytical\u00C2\u00A0 method\u00C2\u00A0 Comments\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0 TG1\u00E2\u0080\u0090136\u00C2\u00A0 573712\u00C2\u00A0 9454484\u00C2\u00A0104.4\u00C2\u00A0+/\u00E2\u0080\u00901.9\u00C2\u00A0Rhyolitic\u00C2\u00A0volcaniclastic\u00C2\u00A0(TG1\u00C2\u00A0deposit\u00C2\u00A0hanging\u00C2\u00A0 wall);\u00C2\u00A0diamond\u00C2\u00A0drill\u00C2\u00A0hole\u00C2\u00A000TG1\u00E2\u0080\u0090136\u00C2\u00A0@\u00C2\u00A050.20\u00C2\u00A0 metres;\u00C2\u00A0poor\u00E2\u0080\u0090moderately\u00C2\u00A0sorted,\u00C2\u00A0sand\u00E2\u0080\u0090pebble\u00C2\u00A0 sized,\u00C2\u00A0re\u00E2\u0080\u0090sedimented\u00C2\u00A0autoclastic\u00C2\u00A0breccia.\u00C2\u00A0 SHRIMP\u00E2\u0080\u0090 RG\u00C2\u00A0 only\u00C2\u00A0~\u00C2\u00A030\u00C2\u00A0zircons\u00C2\u00A0recovered,\u00C2\u00A0nearly\u00C2\u00A0all\u00C2\u00A0<\u00C2\u00A074\u00C2\u00A0\u00C2\u00B5 LW\u00E2\u0080\u0090016\u00C2\u00A0 588523\u00C2\u00A0 9480533\u00C2\u00A0104.7\u00C2\u00A0+/\u00E2\u0080\u00901.4\u00C2\u00A0Rhyolite\u00C2\u00A0porphyry:\u00C2\u00A0dyke\u00C2\u00A0with\u00C2\u00A0very\u00C2\u00A0fine\u00C2\u00A0grained\u00C2\u00A0 quartz\u00C2\u00A0phenocrysts.\u00C2\u00A0 SHRIMP\u00E2\u0080\u0090 RG\u00C2\u00A0 12\u00C2\u00A0grains\u00C2\u00A0analyzed. TG1\u00E2\u0080\u0090111\u00C2\u00A0 573696\u00C2\u00A0 9454532\u00C2\u00A0100.2\u00C2\u00A0+/\u00E2\u0080\u00900.5\u00C2\u00A0Rhyolite\u00C2\u00A0porphyry\u00C2\u00A0breccia:\u00C2\u00A0diamond\u00C2\u00A0drill\u00C2\u00A0hole\u00C2\u00A099\u00E2\u0080\u0090 TG1\u00E2\u0080\u0090111\u00C2\u00A0@\u00C2\u00A0~78\u00E2\u0080\u009088\u00C2\u00A0m;\u00C2\u00A0massive,\u00C2\u00A0light\u00C2\u00A0grey\u00C2\u00A0to\u00C2\u00A0buff,\u00C2\u00A0 feldspar\u00C2\u00A0(5\u00E2\u0080\u009010%,\u00C2\u00A03\u00E2\u0080\u00904\u00C2\u00A0mm)\u00C2\u00A0and\u00C2\u00A0(<3%,\u00C2\u00A0~1\u00C2\u00A0mm)\u00C2\u00A0 phenocrysts.\u00C2\u00A0 TIMS A\u00C2\u00A0small\u00C2\u00A0amount\u00C2\u00A0of\u00C2\u00A0clear,\u00C2\u00A0colorless,\u00C2\u00A0stubby\u00C2\u00A0prismatic\u00C2\u00A0zircon\u00C2\u00A0recovered.\u00C2\u00A0\u00C2\u00A0 All\u00C2\u00A0zircons\u00C2\u00A0>74\u00C2\u00A0\u00C2\u00B5\u00C2\u00A0in\u00C2\u00A0diameter\u00C2\u00A0were\u00C2\u00A0picked\u00C2\u00A0and\u00C2\u00A0subjected\u00C2\u00A0to\u00C2\u00A0strong\u00C2\u00A0air\u00C2\u00A0 abrasion,\u00C2\u00A0and\u00C2\u00A0then\u00C2\u00A0split\u00C2\u00A0into\u00C2\u00A0five\u00C2\u00A0sub\u00E2\u0080\u0090equal\u00C2\u00A0fractions\u00C2\u00A0A,\u00C2\u00A0B,\u00C2\u00A0C,\u00C2\u00A0D,\u00C2\u00A0and\u00C2\u00A0E.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0 LW\u00E2\u0080\u0090086\u00C2\u00A0 595654\u00C2\u00A0 9496749\u00C2\u00A099.3\u00C2\u00A0+/\u00E2\u0080\u0090\u00C2\u00A00.3\u00C2\u00A0 Rhyolite\u00C2\u00A0breccia:\u00C2\u00A01.5\u00C2\u00A0m\u00C2\u00A0thick\u00C2\u00A0debris\u00C2\u00A0flow\u00C2\u00A0unit\u00C2\u00A0 within\u00C2\u00A0a\u00C2\u00A0~10\u00C2\u00A0m\u00C2\u00A0thick\u00C2\u00A0volcaniclastic\u00C2\u00A0sequence\u00C2\u00A0 above\u00C2\u00A0mafic\u00C2\u00A0volcanic\u00C2\u00A0rocks;\u00C2\u00A0sample\u00C2\u00A0is\u00C2\u00A01\u00C2\u00A0~0.5\u00C2\u00A0m\u00C2\u00A0 clast\u00C2\u00A0of\u00C2\u00A0buff\u00C2\u00A0colour\u00C2\u00A0felsic\u00C2\u00A0lava\u00C2\u00A0with\u00C2\u00A0feldspar\u00C2\u00A0(5%,\u00C2\u00A0 3\u00E2\u0080\u00904\u00C2\u00A0mm)\u00C2\u00A0and\u00C2\u00A0quartz\u00C2\u00A0(2\u00E2\u0080\u00903%,\u00C2\u00A0<2\u00C2\u00A0mm)\u00C2\u00A0phenocrysts. TIMS 4\u00C2\u00A0fractions:\u00C2\u00A0A,\u00C2\u00A0B,\u00C2\u00A0C) 1\u00C2\u00A0fraction\u00C2\u00A0with\u00C2\u00A03\u00C2\u00A0splits;\u00C2\u00A0slightly\u00C2\u00A0yellowish\u00C2\u00A0stubby\u00C2\u00A0 prisms\u00C2\u00A0with\u00C2\u00A0l/w\u00C2\u00A0of\u00C2\u00A02\u00E2\u0080\u00903:1;\u00C2\u00A0less\u00C2\u00A010%\u00C2\u00A0broken\u00C2\u00A0crystals;\u00C2\u00A0D)\u00C2\u00A014\u00C2\u00A0crystals\u00C2\u00A0>104\u00C2\u00A0 \u00C2\u00B5;\u00C2\u00A0colourless\u00C2\u00A0and\u00C2\u00A0clear,\u00C2\u00A0broken,\u00C2\u00A0anhedral,\u00C2\u00A0+/\u00E2\u0080\u0090\u00C2\u00A0solid\u00C2\u00A0inclusions,\u00C2\u00A0mostly\u00C2\u00A0 fragments\u00C2\u00A0of\u00C2\u00A0prismatic\u00C2\u00A0crystals;\u00C2\u00A0E)\u00C2\u00A017\u00C2\u00A0crystals\u00C2\u00A0>>74\u00C2\u00A0\u00C2\u00B5;\u00C2\u00A0slightly\u00C2\u00A0yellow\u00C2\u00A0to\u00C2\u00A0 clear\u00C2\u00A0with\u00C2\u00A0minor\u00C2\u00A0inclusions,\u00C2\u00A0l/w\u00C2\u00A0=\u00C2\u00A03\u00E2\u0080\u00904:1;\u00C2\u00A0euhedral,\u00C2\u00A010%\u00C2\u00A0broken;\u00C2\u00A0F)\u00C2\u00A032\u00C2\u00A0 >74\u00C2\u00A0\u00C2\u00B5;\u00C2\u00A0clear\u00C2\u00A0needles\u00C2\u00A0with\u00C2\u00A0rare\u00C2\u00A0solid\u00C2\u00A0inclusions;\u00C2\u00A0euhedral,\u00C2\u00A0l/w=4\u00E2\u0080\u00906:1;\u00C2\u00A0 10%\u00C2\u00A0broken.\u00C2\u00A0 LW\u00E2\u0080\u0090013\u00C2\u00A0 588255\u00C2\u00A0 9482680\u00C2\u00A099.1\u00C2\u00A0+/\u00E2\u0080\u0090\u00C2\u00A01.4\u00C2\u00A0 Rhyolite\u00C2\u00A0porphyry:\u00C2\u00A0quartz\u00C2\u00A0phenocrysts;\u00C2\u00A0columnar joints.\u00C2\u00A0 SHRIMP\u00E2\u0080\u0090 RG\u00C2\u00A0 recovered\u00C2\u00A0only\u00C2\u00A0small\u00C2\u00A0yield;\u00C2\u00A012\u00C2\u00A0zircons\u00C2\u00A0analyzed. LW\u00E2\u0080\u0090078\u00C2\u00A0 589870\u00C2\u00A0 9490590\u00C2\u00A098.8\u00C2\u00A0+/\u00E2\u0080\u00901.0\u00C2\u00A0 Polylithic\u00C2\u00A0boulder\u00C2\u00A0breccia:\u00C2\u00A0dominated\u00C2\u00A0by\u00C2\u00A0 basaltic\u00E2\u0080\u0090andesite,\u00C2\u00A0lesser\u00C2\u00A0rhyolite\u00C2\u00A0and\u00C2\u00A0minor\u00C2\u00A0 calcareous\u00C2\u00A0sedimentary\u00C2\u00A0clasts;\u00C2\u00A0sample\u00C2\u00A0is\u00C2\u00A0>1\u00C2\u00A0m,\u00C2\u00A0 subround,\u00C2\u00A0feldspar\u00E2\u0080\u0090quartz\u00C2\u00A0porphyritic\u00C2\u00A0clast;\u00C2\u00A05\u00E2\u0080\u00907%\u00C2\u00A0 pink,\u00C2\u00A0stubby\u00C2\u00A0feldspars\u00C2\u00A0to\u00C2\u00A05\u00C2\u00A0mm;\u00C2\u00A05\u00E2\u0080\u00907%\u00C2\u00A0quartz\u00C2\u00A0to\u00C2\u00A0 5\u00E2\u0080\u00906\u00C2\u00A0mm.\u00C2\u00A0 SHRIMP\u00E2\u0080\u0090 RG\u00C2\u00A0 recovered\u00C2\u00A0only\u00C2\u00A0small\u00C2\u00A0yield;\u00C2\u00A012\u00C2\u00A0zircons\u00C2\u00A0analyzed. LW\u00E2\u0080\u0090010\u00C2\u00A0 587799\u00C2\u00A0 9489045\u00C2\u00A097.0\u00C2\u00A0+/\u00E2\u0080\u00900.4\u00C2\u00A0 Dacite\u00C2\u00A0porphyry:\u00C2\u00A0light\u00C2\u00A0green,\u00C2\u00A0aphanitic,\u00C2\u00A0aphyric,\u00C2\u00A0 stubby\u00C2\u00A0plagioclase\u00C2\u00A0(5%,\u00C2\u00A01\u00E2\u0080\u00902\u00C2\u00A0mm)\u00C2\u00A0phenocrysts,\u00C2\u00A0 massive,\u00C2\u00A0partly\u00C2\u00A0sericitized.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 TIMS 5\u00C2\u00A0fractions/subfractions:\u00C2\u00A0A)\u00C2\u00A042\u00C2\u00A0grains\u00C2\u00A074\u00E2\u0080\u0090104\u00C2\u00A0\u00C2\u00B5;\u00C2\u00A0B,C,D,E)\u00C2\u00A0~250\u00C2\u00A0grains\u00C2\u00A0 <74\u00C2\u00A0\u00C2\u00B5;\u00C2\u00A04\u00C2\u00A0splits;\u00C2\u00A0stubby\u00C2\u00A0prisms\u00C2\u00A0l/w=2\u00E2\u0080\u00903:1.\u00C2\u00A0\u00C2\u00A0Picked\u00C2\u00A095%\u00C2\u00A0of\u00C2\u00A0zircons\u00C2\u00A0 recovered.\u00C2\u00A0 LW\u00E2\u0080\u0090077\u00C2\u00A0 580452\u00C2\u00A0 9501568\u00C2\u00A090.3\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A095.3\u00C2\u00A0 Dacite:\u00C2\u00A0flow\u00C2\u00A0and\u00C2\u00A0breccia\u00C2\u00A0with\u00C2\u00A0partially\u00C2\u00A0digested\u00C2\u00A0 granitic\u00C2\u00A0xenoliths.\u00C2\u00A0 TIMS Analyzed\u00C2\u00A0nearly\u00C2\u00A0all\u00C2\u00A0zircons\u00C2\u00A0recovered\u00C2\u00A0(~300).\u00C2\u00A0\u00C2\u00A095%\u00C2\u00A0<\u00C2\u00A074\u00C2\u00A0\u00C2\u00B5,\u00C2\u00A0clear\u00C2\u00A0to\u00C2\u00A0 pink,\u00C2\u00A0stubby\u00C2\u00A0prisms;\u00C2\u00A06\u00C2\u00A0splits.\u00C2\u00A0 Chapter\u00C2\u00A03\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A058\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A03\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A059\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Table\u00C2\u00A02.1\u00C2\u00A0continued.\u00C2\u00A0 \u00C2\u00A0 Sample\u00C2\u00A0ID\u00C2\u00A0 UTM\u00C2\u00A0 Easting\u00C2\u00A0 UTM\u00C2\u00A0 Westing\u00C2\u00A0 Calculated\u00C2\u00A0 age\u00C2\u00A0+/\u00E2\u0080\u0090\u00C2\u00A0 error\u00C2\u00A0(Ma)\u00C2\u00A0 Description\u00C2\u00A0 Analytical\u00C2\u00A0 method\u00C2\u00A0 Comments\u00C2\u00A0 LW\u00E2\u0080\u0090043\u00C2\u00A0 567138\u00C2\u00A0 9482242\u00C2\u00A091.1\u00C2\u00A0+/\u00E2\u0080\u00901.0\u00C2\u00A0 Rhyolite\u00C2\u00A0porphyry:\u00C2\u00A0flow\u00E2\u0080\u0090banded\u00C2\u00A0dyke;\u00C2\u00A0quartz\u00C2\u00A0and feldspar\u00C2\u00A0phenocrysts.\u00C2\u00A0 \u00C2\u00A0SHRIMP\u00E2\u0080\u0090 RG\u00C2\u00A0 recovered\u00C2\u00A0only\u00C2\u00A0small\u00C2\u00A0yield;\u00C2\u00A012\u00C2\u00A0zircons\u00C2\u00A0analyzed. LW\u00E2\u0080\u0090051\u00C2\u00A0 562449\u00C2\u00A0 9479084\u00C2\u00A0Proterozoic\u00C2\u00A0 inheritance\u00C2\u00A0 Rhyolite\u00C2\u00A0tuff:\u00C2\u00A0quartz\u00C2\u00A0crystal\u00E2\u0080\u0090rich,\u00C2\u00A0lithic\u00E2\u0080\u0090bearing;\u00C2\u00A0 quartz\u00C2\u00A0to\u00C2\u00A05\u00E2\u0080\u00906\u00C2\u00A0mm.\u00C2\u00A0 TIMS 4\u00C2\u00A0fractions:\u00C2\u00A0A)\u00C2\u00A0>104\u00C2\u00A0\u00C2\u00B5;\u00C2\u00A0l/w=5/1;\u00C2\u00A0colourless,\u00C2\u00A0clear\u00C2\u00A0with\u00C2\u00A0complex\u00C2\u00A0 terminations;\u00C2\u00A0B)\u00C2\u00A0>74\u00C2\u00A0\u00C2\u00B5,\u00C2\u00A01\u00C2\u00A0crystal\u00C2\u00A0>104;\u00C2\u00A0stubby\u00C2\u00A0and\u00C2\u00A0broken\u00C2\u00A0crystals;\u00C2\u00A0l/w\u00C2\u00A0 =\u00C2\u00A02\u00E2\u0080\u00903/1;\u00C2\u00A0possible\u00C2\u00A0zoning;\u00C2\u00A0C,D)\u00C2\u00A0small,\u00C2\u00A0<74\u00C2\u00A0\u00C2\u00B5,\u00C2\u00A0stubby\u00C2\u00A0prisms,\u00C2\u00A0clear\u00C2\u00A0to\u00C2\u00A0 pink,\u00C2\u00A0l/w=~2:1.\u00C2\u00A0\u00C2\u00A0Picked\u00C2\u00A0nearly\u00C2\u00A0all\u00C2\u00A0zircons\u00C2\u00A0recovered.\u00C2\u00A0 LW\u00E2\u0080\u0090066\u00C2\u00A0 588107\u00C2\u00A0 9489337\u00C2\u00A0~99.8?\u00C2\u00A0\u00C2\u00A0 Proterozoic\u00C2\u00A0 inheritance\u00C2\u00A0 Rhyolite\u00C2\u00A0porphyry\u00C2\u00A0breccia:\u00C2\u00A0rhyolite\u00C2\u00A0breccia\u00C2\u00A0mixed\u00C2\u00A0 with\u00C2\u00A0sedimentary\u00C2\u00A0rock\u00C2\u00A0clasts;\u00C2\u00A0sample\u00C2\u00A0is\u00C2\u00A0from\u00C2\u00A020\u00C2\u00A0 separate\u00C2\u00A0<20\u00C2\u00A0cm\u00C2\u00A0subround\u00C2\u00A0clasts;\u00C2\u00A0quartz\u00C2\u00A0(5%,\u00C2\u00A01\u00E2\u0080\u0090 2mm)\u00C2\u00A0phenocrysts.\u00C2\u00A0 SHRIMP\u00E2\u0080\u0090 RG\u00C2\u00A0 18\u00C2\u00A0zircons\u00C2\u00A0recovered;\u00C2\u00A011\u00C2\u00A0grains\u00C2\u00A0analyzed,\u00C2\u00A0all\u00C2\u00A0<\u00C2\u00A0104.\u00C2\u00A0Mostly\u00C2\u00A0stubby\u00C2\u00A0 prisms,\u00C2\u00A0colourless\u00C2\u00A0to\u00C2\u00A0slightly\u00C2\u00A0pink.\u00C2\u00A0 LW\u00E2\u0080\u0090026\u00C2\u00A0 569870\u00C2\u00A0 9478046\u00C2\u00A0Proterozoic\u00C2\u00A0 inheritance\u00C2\u00A0 Rhyolite\u00C2\u00A0porphyry:\u00C2\u00A0dyke;\u00C2\u00A0light\u00C2\u00A0grey\u00E2\u0080\u0090green;\u00C2\u00A0quartz\u00C2\u00A0 (<5%,\u00C2\u00A0<\u00C2\u00A01mm)\u00C2\u00A0and\u00C2\u00A0feldspar\u00C2\u00A0(5%,\u00C2\u00A01\u00C2\u00A0mm)\u00C2\u00A0 phenocrysts.\u00C2\u00A0 SHRIMP\u00E2\u0080\u0090 RG\u00C2\u00A0 17\u00C2\u00A0grains\u00C2\u00A0recovered;\u00C2\u00A011\u00C2\u00A0grains\u00C2\u00A0<\u00C2\u00A0104\u00C2\u00A0\u00C2\u00B5;\u00C2\u00A0some\u00C2\u00A0broken\u00C2\u00A0crystal\u00C2\u00A0fragments\u00C2\u00A0 in\u00C2\u00A0the\u00C2\u00A0>104.\u00C2\u00A0 LW\u00E2\u0080\u0090033\u00C2\u00A0 \u00C2\u00A0 569685\u00C2\u00A0 9478490\u00C2\u00A0Proterozoic\u00C2\u00A0 inheritance\u00C2\u00A0 Rhyolite\u00C2\u00A0porphyry\u00C2\u00A0breccia:\u00C2\u00A0polylithic,\u00C2\u00A0mafic\u00E2\u0080\u0090 dominated\u00C2\u00A0volcanic\u00C2\u00A0breccia;\u00C2\u00A0sample\u00C2\u00A0from\u00C2\u00A0a\u00C2\u00A0~70\u00C2\u00A0 cm\u00C2\u00A0rhyolite\u00C2\u00A0clast\u00C2\u00A0with\u00C2\u00A0feldspar\u00E2\u0080\u0090quartz\u00C2\u00A0 phenocrysts.\u00C2\u00A0 SHRIMP\u00E2\u0080\u0090 RG\u00C2\u00A0 recovered\u00C2\u00A0only\u00C2\u00A0small\u00C2\u00A0yield;\u00C2\u00A013\u00C2\u00A0data\u00C2\u00A0points;\u00C2\u00A012\u00C2\u00A0grains. \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A02.3\u00C2\u00A0(on\u00C2\u00A0the\u00C2\u00A0following\u00C2\u00A0page).\u00C2\u00A0\u00C2\u00A0Schematic\u00C2\u00A0paleogeographic\u00C2\u00A0model\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0development\u00C2\u00A0of\u00C2\u00A0 Per\u00C3\u00BA\u00E2\u0080\u0090Ecuador\u00C2\u00A0segment\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0western\u00C2\u00A0margin\u00C2\u00A0of\u00C2\u00A0South\u00C2\u00A0America\u00C2\u00A0(SA)\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0Jurassic\u00C2\u00A0to\u00C2\u00A0 present\u00C2\u00A0using\u00C2\u00A0data\u00C2\u00A0from\u00C2\u00A0Mourier\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1988),\u00C2\u00A0Mitouard\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1990),\u00C2\u00A0Litherland\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1994),\u00C2\u00A0 Aspden\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1995),\u00C2\u00A0\u00C2\u00A0Noble\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1997),\u00C2\u00A0Arculus\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1999),\u00C2\u00A0Benavides\u00E2\u0080\u0090C\u00C3\u00A1ceres\u00C2\u00A0(1999),\u00C2\u00A0 Jaillard\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(2000),\u00C2\u00A0Bosch\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(2002),\u00C2\u00A0and\u00C2\u00A0Polliand\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(2005).\u00C2\u00A0\u00C2\u00A0A.\u00C2\u00A0Jurassic\u00C2\u00A0to\u00C2\u00A0earliest\u00C2\u00A0Early\u00C2\u00A0 Cretaceous:\u00C2\u00A0~SE\u00E2\u0080\u0090directed\u00C2\u00A0convergence\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0proto\u00E2\u0080\u0090Farallon\u00E2\u0080\u0090Caribbean\u00C2\u00A0ocean\u00C2\u00A0plate\u00C2\u00A0with\u00C2\u00A0 continental\u00C2\u00A0SA;\u00C2\u00A0subduction\u00C2\u00A0occurs\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0Ecuadorian\u00C2\u00A0segment,\u00C2\u00A0whereas\u00C2\u00A0the\u00C2\u00A0Peruvian\u00C2\u00A0NNW\u00E2\u0080\u0090 trending\u00C2\u00A0margin\u00C2\u00A0is\u00C2\u00A0a\u00C2\u00A0sinistral\u00C2\u00A0transform;\u00C2\u00A0Amotape\u00C2\u00A0terrane\u00C2\u00A0is\u00C2\u00A0a\u00C2\u00A0micro\u00E2\u0080\u0090continent\u00C2\u00A0approaching\u00C2\u00A0SA;\u00C2\u00A0 B)\u00C2\u00A0change\u00C2\u00A0in\u00C2\u00A0convergence\u00C2\u00A0direction\u00C2\u00A0from\u00C2\u00A0SE\u00C2\u00A0to\u00C2\u00A0~NE;\u00C2\u00A0accretion\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Amotape\u00C2\u00A0terrane,\u00C2\u00A0notably\u00C2\u00A0 along\u00C2\u00A0the\u00C2\u00A0Peruvian\u00C2\u00A0segment;\u00C2\u00A0dextral\u00C2\u00A0faulting\u00C2\u00A0of\u00C2\u00A0Amotape\u00C2\u00A0terrane\u00C2\u00A0and\u00C2\u00A0clockwise\u00C2\u00A0rotation\u00C2\u00A0of\u00C2\u00A0 blocks;\u00C2\u00A0ocean\u00E2\u0080\u0090continental\u00C2\u00A0plate\u00C2\u00A0boundary\u00C2\u00A0\u00E2\u0080\u0098jumps\u00E2\u0080\u0099\u00C2\u00A0toward\u00C2\u00A0the\u00C2\u00A0west;\u00C2\u00A0during\u00C2\u00A0this\u00C2\u00A0period\u00C2\u00A0the\u00C2\u00A0NW\u00E2\u0080\u0090 trending\u00C2\u00A0Peruvian\u00C2\u00A0margin\u00C2\u00A0becomes\u00C2\u00A0a\u00C2\u00A0subduction\u00C2\u00A0zone\u00C2\u00A0whereas\u00C2\u00A0the\u00C2\u00A0Ecuadorian\u00C2\u00A0NE\u00E2\u0080\u0090trending\u00C2\u00A0 margin\u00C2\u00A0becomes\u00C2\u00A0a\u00C2\u00A0dextral\u00C2\u00A0transform.\u00C2\u00A0\u00C2\u00A0C)\u00C2\u00A0trench\u00C2\u00A0\u00E2\u0080\u0098roll\u00E2\u0080\u0090back\u00E2\u0080\u0099\u00C2\u00A0occurring\u00C2\u00A0along\u00C2\u00A0Peruvian\u00C2\u00A0margin\u00C2\u00A0and\u00C2\u00A0 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Formation:\u00C2\u00A0\u00C2\u00A0A.\u00C2\u00A0Massive\u00C2\u00A0feldspar\u00C2\u00A0porphyritic\u00C2\u00A0rhyolite.\u00C2\u00A0\u00C2\u00A0Scale\u00C2\u00A0units\u00C2\u00A0are\u00C2\u00A0mm.\u00C2\u00A0\u00C2\u00A0TG1\u00C2\u00A0area.\u00C2\u00A0\u00C2\u00A0B.\u00C2\u00A0\u00C2\u00A0Flow\u00E2\u0080\u0090 banded\u00C2\u00A0rhyolite\u00C2\u00A0autobreccia;\u00C2\u00A0these\u00C2\u00A0breccias\u00C2\u00A0typically\u00C2\u00A0grade\u00C2\u00A0into\u00C2\u00A0lavas.\u00C2\u00A0\u00C2\u00A0Textures\u00C2\u00A0partly\u00C2\u00A0masked\u00C2\u00A0 by\u00C2\u00A0quartz\u00C2\u00A0and\u00C2\u00A0sericite\u00C2\u00A0alteration.\u00C2\u00A0\u00C2\u00A0TG3\u00C2\u00A0area.\u00C2\u00A0C.\u00C2\u00A0\u00C2\u00A0Rhyolitic,\u00C2\u00A0unsorted,\u00C2\u00A0clast\u00E2\u0080\u0090supported,\u00C2\u00A0 volcaniclastic\u00C2\u00A0rock\u00C2\u00A0with\u00C2\u00A0pebble\u00E2\u0080\u0090size\u00C2\u00A0clasts\u00C2\u00A0and\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0fragments\u00C2\u00A0(near\u00C2\u00A0the\u00C2\u00A0TG3\u00C2\u00A0 deposit).\u00C2\u00A0\u00C2\u00A0D.\u00C2\u00A0Green\u00E2\u0080\u0090grey,\u00C2\u00A0feldspar\u00C2\u00A0porphyritic\u00C2\u00A0dacite\u00C2\u00A0with\u00C2\u00A0large\u00C2\u00A0flow\u00E2\u0080\u0090foliated\u00C2\u00A0chlorite\u00E2\u0080\u0090quartz\u00C2\u00A0 \u00E2\u0080\u0098pipe\u00E2\u0080\u0099\u00C2\u00A0amygdules.\u00C2\u00A0\u00C2\u00A0Hanging\u00C2\u00A0wall\u00C2\u00A0to\u00C2\u00A0TG3\u00C2\u00A0deposit.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 Page\u00C2\u00A067\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A02.9.\u00C2\u00A0\u00C2\u00A0Field\u00C2\u00A0photographs\u00C2\u00A0of\u00C2\u00A0mafic\u00C2\u00A0rocks\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation:\u00C2\u00A0\u00C2\u00A0A.\u00C2\u00A0Typical\u00C2\u00A0 porphyritic\u00C2\u00A0textures\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation\u00C2\u00A0porphyritic\u00C2\u00A0basalt.\u00C2\u00A0\u00C2\u00A0Sample\u00C2\u00A0contains\u00C2\u00A0~20%\u00C2\u00A0 feldspar\u00C2\u00A0phenocrysts\u00C2\u00A0to\u00C2\u00A0>1\u00C2\u00A0cm\u00C2\u00A0in\u00C2\u00A0an\u00C2\u00A0aphanitic\u00C2\u00A0matrix.\u00C2\u00A0\u00C2\u00A0Non\u00E2\u0080\u0090amygdaloidal.\u00C2\u00A0\u00C2\u00A0Subvolcanic\u00C2\u00A0or\u00C2\u00A0thick\u00C2\u00A0 flow\u00C2\u00A0facies.\u00C2\u00A0\u00C2\u00A0B.\u00C2\u00A0Bleached\u00E2\u0080\u0090looking,\u00C2\u00A0boulder\u00C2\u00A0size,\u00C2\u00A0subround\u00C2\u00A0clasts\u00C2\u00A0(C)\u00C2\u00A0of\u00C2\u00A0basalt\u00C2\u00A0feldspar\u00C2\u00A0porphyry\u00C2\u00A0in\u00C2\u00A0 a\u00C2\u00A0fine\u00C2\u00A0matrix\u00C2\u00A0of\u00C2\u00A0dark\u00C2\u00A0grey\u00C2\u00A0feldspar\u00C2\u00A0porphyritic\u00C2\u00A0material\u00C2\u00A0(M).\u00C2\u00A0\u00C2\u00A0Clasts\u00C2\u00A0show\u00C2\u00A0in\u00E2\u0080\u0090situ\u00C2\u00A0breccia\u00C2\u00A0textures\u00C2\u00A0 (jigsaw\u00E2\u0080\u0090fit)\u00C2\u00A0attributed\u00C2\u00A0to\u00C2\u00A0progressive\u00C2\u00A0fragmentation\u00C2\u00A0of\u00C2\u00A0blocks\u00C2\u00A0during\u00C2\u00A0transport.\u00C2\u00A0\u00C2\u00A0C.\u00C2\u00A0Unsorted,\u00C2\u00A0 non\u00E2\u0080\u0090stratified\u00C2\u00A0basaltic\u00C2\u00A0cobble\u00E2\u0080\u0090\u00C2\u00A0to\u00C2\u00A0pebble\u00E2\u0080\u0090sized\u00C2\u00A0lithic\u00C2\u00A0and\u00C2\u00A0feldspar\u00C2\u00A0crystal\u00E2\u0080\u0090bearing\u00C2\u00A0volcaniclastic\u00C2\u00A0 rock.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0sample\u00C2\u00A0contains\u00C2\u00A0an\u00C2\u00A0equal\u00C2\u00A0proportion\u00C2\u00A0of\u00C2\u00A0aphyric\u00C2\u00A0to\u00C2\u00A0weakly\u00C2\u00A0feldspar\u00C2\u00A0porphyritic\u00C2\u00A0(W)\u00C2\u00A0 clasts\u00C2\u00A0and\u00C2\u00A0coarse\u00C2\u00A0feldspar\u00C2\u00A0(C)\u00C2\u00A0porphyry\u00C2\u00A0clasts.\u00C2\u00A0\u00C2\u00A0Amygdaloidal\u00C2\u00A0clasts\u00C2\u00A0(A)\u00C2\u00A0are\u00C2\u00A0present\u00C2\u00A0but\u00C2\u00A0are\u00C2\u00A0 generally\u00C2\u00A0not\u00C2\u00A0common.\u00C2\u00A0\u00C2\u00A0Clast\u00C2\u00A0margins\u00C2\u00A0often\u00C2\u00A0are\u00C2\u00A0not\u00C2\u00A0easily\u00C2\u00A0discernible.\u00C2\u00A0\u00C2\u00A0D.\u00C2\u00A0Thin\u00E2\u0080\u0090\u00C2\u00A0to\u00C2\u00A0thick\u00E2\u0080\u0090bedded\u00C2\u00A0 feldspar\u00C2\u00A0crystal\u00C2\u00A0to\u00C2\u00A0ash\u00E2\u0080\u0090sized\u00C2\u00A0tuff;\u00C2\u00A0reworked\u00C2\u00A0facies\u00C2\u00A0at\u00C2\u00A0top\u00C2\u00A0of\u00C2\u00A0formation.\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 Page\u00C2\u00A068\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A02.10.\u00C2\u00A0\u00C2\u00A0Field\u00C2\u00A0photographs\u00C2\u00A0of\u00C2\u00A0mafic\u00C2\u00A0rocks\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation:\u00C2\u00A0\u00C2\u00A0A.\u00C2\u00A0Moderately\u00C2\u00A0 west\u00E2\u0080\u0090dipping,\u00C2\u00A0thick\u00C2\u00A0massive\u00C2\u00A0basaltic\u00E2\u0080\u0090andesite\u00C2\u00A0flows.\u00C2\u00A0\u00C2\u00A0Felsic\u00C2\u00A0stocks\u00C2\u00A0and\u00C2\u00A0dykes\u00C2\u00A0cut\u00C2\u00A0perpendicular\u00C2\u00A0 to\u00C2\u00A0bedding.\u00C2\u00A0\u00C2\u00A0B.\u00C2\u00A0\u00C2\u00A0Basaltic\u00C2\u00A0andesite\u00C2\u00A0dykes\u00C2\u00A0with\u00C2\u00A0strongly\u00C2\u00A0flow\u00C2\u00A0foliation\u00C2\u00A0defined\u00C2\u00A0by\u00C2\u00A0flattened\u00C2\u00A0and\u00C2\u00A0 large\u00C2\u00A0vesicules\u00C2\u00A0(silica\u00C2\u00A0amygdules\u00C2\u00A0up\u00C2\u00A0to\u00C2\u00A030\u00C2\u00A0cm).\u00C2\u00A0\u00C2\u00A0C.\u00C2\u00A0Polylithic,\u00C2\u00A0basaltic\u00E2\u0080\u0090andesite\u00C2\u00A0dominated,\u00C2\u00A0mass\u00C2\u00A0 flow\u00C2\u00A0deposit.\u00C2\u00A0\u00C2\u00A0Not\u00C2\u00A0the\u00C2\u00A0fractures\u00C2\u00A0and\u00C2\u00A0in\u00E2\u0080\u0090situ\u00C2\u00A0fragmentation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0clasts\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0mass\u00C2\u00A0transport\u00C2\u00A0 (see\u00C2\u00A0arrows).\u00C2\u00A0\u00C2\u00A0D.\u00C2\u00A0Cracked\u00C2\u00A0and\u00C2\u00A0brecciated\u00C2\u00A0outer\u00C2\u00A0crust\u00C2\u00A0of\u00C2\u00A0basaltic\u00C2\u00A0andesite\u00C2\u00A0lava\u00C2\u00A0flow\u00C2\u00A0and\u00C2\u00A0 interstitial\u00C2\u00A0hyaloclastite\u00C2\u00A0resulting\u00C2\u00A0from\u00C2\u00A0quenching\u00C2\u00A0of\u00C2\u00A0exposed\u00C2\u00A0lava.\u00C2\u00A0\u00C2\u00A0E.\u00C2\u00A0Mafic\u00C2\u00A0lobes\u00C2\u00A0(M)\u00C2\u00A0injected\u00C2\u00A0 into\u00C2\u00A0felsic\u00C2\u00A0quartz\u00E2\u0080\u0090crystal\u00C2\u00A0tuffs\u00C2\u00A0(T).\u00C2\u00A0\u00C2\u00A0Tuffs\u00C2\u00A0show\u00C2\u00A0\u00E2\u0080\u0098soft\u00E2\u0080\u0090sediment\u00E2\u0080\u0099\u00C2\u00A0deformation\u00C2\u00A0textures\u00C2\u00A0and\u00C2\u00A0mafic\u00C2\u00A0 flows\u00C2\u00A0show\u00C2\u00A0columnar\u00C2\u00A0jointing\u00C2\u00A0indicating\u00C2\u00A0tuffs\u00C2\u00A0were\u00C2\u00A0non\u00E2\u0080\u0090welded/non\u00E2\u0080\u0090lithified\u00C2\u00A0during\u00C2\u00A0deposition\u00C2\u00A0 of\u00C2\u00A0mafic\u00C2\u00A0flows.\u00C2\u00A0\u00C2\u00A0F.\u00C2\u00A0\u00C2\u00A0Lithic\u00C2\u00A0and\u00C2\u00A0quartz\u00E2\u0080\u0090feldspar\u00C2\u00A0crystal\u00C2\u00A0rhyolitic\u00C2\u00A0tuff.\u00C2\u00A0\u00C2\u00A0Colouration\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0domains\u00C2\u00A0 are\u00C2\u00A0a\u00C2\u00A0result\u00C2\u00A0of\u00C2\u00A0secondary\u00C2\u00A0recrystallization\u00C2\u00A0to\u00C2\u00A0quartzo\u00E2\u0080\u0090feldspathic\u00C2\u00A0(light)\u00C2\u00A0and\u00C2\u00A0chloritic\u00C2\u00A0(+clay)\u00C2\u00A0 assemblages\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0devitrification\u00C2\u00A0of\u00C2\u00A0glass\u00C2\u00A0component.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 Page\u00C2\u00A069\u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A02.10\u00C2\u00A0(continued).\u00C2\u00A0\u00C2\u00A0G.\u00C2\u00A0Rhyolitic\u00C2\u00A0quartz\u00C2\u00A0crystal\u00E2\u0080\u0090rich\u00C2\u00A0and\u00C2\u00A0lithic\u00C2\u00A0tuff.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0H.\u00C2\u00A0Coarse,\u00C2\u00A0boulder\u00C2\u00A0 breccia\u00C2\u00A0with\u00C2\u00A0chaotic,\u00C2\u00A0unsorted,\u00C2\u00A0subround\u00C2\u00A0(pillow?)\u00C2\u00A0clasts.\u00C2\u00A0\u00C2\u00A0Talus\u00C2\u00A0breccia.\u00C2\u00A0\u00C2\u00A0I.\u00C2\u00A0Medium\u00C2\u00A0bedded,\u00C2\u00A0 well\u00C2\u00A0sorted\u00C2\u00A0and\u00C2\u00A0locally\u00C2\u00A0cross\u00C2\u00A0bedded\u00C2\u00A0(arrow),\u00C2\u00A0pebble\u00E2\u0080\u0090\u00C2\u00A0to\u00C2\u00A0sand\u00E2\u0080\u0090sized,\u00C2\u00A0mafic\u00E2\u0080\u0090dominated\u00C2\u00A0 volcaniclastic\u00C2\u00A0rocks.\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 Page\u00C2\u00A070\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A02.11.\u00C2\u00A0\u00C2\u00A0A.\u00C2\u00A0thin\u00C2\u00A0bedded\u00C2\u00A0arenaceous\u00C2\u00A0sequence\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Formation;\u00C2\u00A0massive\u00C2\u00A0unit\u00C2\u00A0 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Geologists,\u00C2\u00A0Special\u00C2\u00A0Publication\u00C2\u00A0Number\u00C2\u00A07,\u00C2\u00A0pp.\u00C2\u00A061\u00E2\u0080\u0090107.\u00C2\u00A0 \u00C2\u00A0 Bosch,\u00C2\u00A0D.,\u00C2\u00A0Gabriele,\u00C2\u00A0P.,\u00C2\u00A0Lapierre,\u00C2\u00A0H.,\u00C2\u00A0Malfere,\u00C2\u00A0J.,\u00C2\u00A0and\u00C2\u00A0Jaillard,\u00C2\u00A0E.\u00C2\u00A0\u00C2\u00A02002.\u00C2\u00A0\u00C2\u00A0Geodynamic\u00C2\u00A0significance\u00C2\u00A0 of\u00C2\u00A0the\u00C2\u00A0Raspas\u00C2\u00A0metamorphic\u00C2\u00A0complex\u00C2\u00A0(SW\u00C2\u00A0Ecuador);\u00C2\u00A0geochemical\u00C2\u00A0and\u00C2\u00A0isotopic\u00C2\u00A0constraints.\u00C2\u00A0 Tectonophysics,\u00C2\u00A0345:\u00C2\u00A083\u00E2\u0080\u0090102.\u00C2\u00A0 \u00C2\u00A0 Cas,\u00C2\u00A0R.A.F.\u00C2\u00A0\u00C2\u00A01992.\u00C2\u00A0\u00C2\u00A0Submarine\u00C2\u00A0volcanism:\u00C2\u00A0eruption\u00C2\u00A0styles,\u00C2\u00A0products,\u00C2\u00A0and\u00C2\u00A0relevance\u00C2\u00A0to\u00C2\u00A0 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Geology\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0Bulletin\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0Economic\u00C2\u00A0Geologists,\u00C2\u00A099:\u00C2\u00A01085\u00E2\u0080\u00901106.\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Cobbing,\u00C2\u00A0E.J.,\u00C2\u00A0Pitcher,\u00C2\u00A0W.S.,\u00C2\u00A0Wilson,\u00C2\u00A0J.J.,\u00C2\u00A0Baldock,\u00C2\u00A0J.W.,\u00C2\u00A0Taylor,\u00C2\u00A0W.P.,\u00C2\u00A0McCourt,\u00C2\u00A0W.,\u00C2\u00A0and\u00C2\u00A0Snelling,\u00C2\u00A0 N.J.\u00C2\u00A0\u00C2\u00A01981.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0geology\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Western\u00C2\u00A0Cordillera\u00C2\u00A0of\u00C2\u00A0Northern\u00C2\u00A0Per\u00C3\u00BA.\u00C2\u00A0\u00C2\u00A0Institute\u00C2\u00A0of\u00C2\u00A0Geological\u00C2\u00A0 Sciences,\u00C2\u00A0Natural\u00C2\u00A0Environment\u00C2\u00A0Research\u00C2\u00A0Council,\u00C2\u00A0Overseas\u00C2\u00A0Memoir\u00C2\u00A05,\u00C2\u00A0143\u00C2\u00A0p.\u00C2\u00A0 \u00C2\u00A0 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Geological\u00C2\u00A0Congress,\u00C2\u00A0Rio\u00C2\u00A0de\u00C2\u00A0Janeiro,\u00C2\u00A0Brazil.\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0U.G.\u00C2\u00A0Cordani,\u00C2\u00A0E.J.\u00C2\u00A0Milani,\u00C2\u00A0A.\u00C2\u00A0Thomaz\u00C2\u00A0 Filho\u00C2\u00A0and\u00C2\u00A0D.A.\u00C2\u00A0Campos,\u00C2\u00A0pp.\u00C2\u00A0481\u00E2\u0080\u0093559.\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 Page\u00C2\u00A079\u00C2\u00A0 \u00C2\u00A0 Jolivet,\u00C2\u00A0L.,\u00C2\u00A0and\u00C2\u00A0Tamaki,\u00C2\u00A0K.\u00C2\u00A0\u00C2\u00A01992.\u00C2\u00A0\u00C2\u00A0Neogene\u00C2\u00A0kinematics\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Japan\u00C2\u00A0Sea\u00C2\u00A0region\u00C2\u00A0and\u00C2\u00A0volcanic\u00C2\u00A0 activity\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0NE\u00E2\u0080\u0090Japan\u00C2\u00A0arc.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0Proceedings\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Ocean\u00C2\u00A0Drilling\u00C2\u00A0Program,\u00C2\u00A0Scientific\u00C2\u00A0 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Challenger,\u00C2\u00A0Walvis\u00C2\u00A0Bay,\u00C2\u00A0South\u00C2\u00A0Africa\u00C2\u00A0to\u00C2\u00A0Recife,\u00C2\u00A0Brazil,\u00C2\u00A0July\u00E2\u0080\u0090September,\u00C2\u00A01980,\u00C2\u00A0Initial\u00C2\u00A0Reports\u00C2\u00A0 of\u00C2\u00A0the\u00C2\u00A0Deep\u00C2\u00A0Sea\u00C2\u00A0Drilling\u00C2\u00A0Project,\u00C2\u00A075:\u00C2\u00A0469\u00E2\u0080\u0090481.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0 Soler,\u00C2\u00A0P.\u00C2\u00A0and\u00C2\u00A0Bonhomme,\u00C2\u00A0M.G.\u00C2\u00A0\u00C2\u00A01990.\u00C2\u00A0\u00C2\u00A0Relation\u00C2\u00A0of\u00C2\u00A0magmatic\u00C2\u00A0activity\u00C2\u00A0to\u00C2\u00A0plate\u00C2\u00A0dynamics\u00C2\u00A0in\u00C2\u00A0central\u00C2\u00A0 Peru\u00C2\u00A0from\u00C2\u00A0Late\u00C2\u00A0Cretaceous\u00C2\u00A0to\u00C2\u00A0present.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0Plutonism\u00C2\u00A0from\u00C2\u00A0Antarctica\u00C2\u00A0to\u00C2\u00A0Alaska.\u00C2\u00A0\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0 S.M.\u00C2\u00A0Kay\u00C2\u00A0and\u00C2\u00A0C.W.\u00C2\u00A0Rapela.\u00C2\u00A0\u00C2\u00A0Geological\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0America\u00C2\u00A0Special\u00C2\u00A0Paper\u00C2\u00A0241,\u00C2\u00A0pp.\u00C2\u00A0173\u00E2\u0080\u0090192.\u00C2\u00A0 \u00C2\u00A0 Spikings,\u00C2\u00A0R.A.,\u00C2\u00A0Winkler,\u00C2\u00A0W.,\u00C2\u00A0Hughes,\u00C2\u00A0R.A.\u00C2\u00A0and\u00C2\u00A0Handler,\u00C2\u00A0R.\u00C2\u00A0\u00C2\u00A02005.\u00C2\u00A0\u00C2\u00A0Thermochronology\u00C2\u00A0of\u00C2\u00A0 allochthonous\u00C2\u00A0terranes\u00C2\u00A0in\u00C2\u00A0Ecuador:\u00C2\u00A0Unraveling\u00C2\u00A0the\u00C2\u00A0accretionary\u00C2\u00A0and\u00C2\u00A0post\u00E2\u0080\u0090accretionary\u00C2\u00A0 history\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Northern\u00C2\u00A0Andes.\u00C2\u00A0\u00C2\u00A0Tectonophysics,\u00C2\u00A0399:\u00C2\u00A0195\u00E2\u0080\u0090220.\u00C2\u00A0 \u00C2\u00A0 Steinm\u00C3\u00BCller,\u00C2\u00A0K.,\u00C2\u00A0Chac\u00C3\u00B3n\u00C2\u00A0Abad,\u00C2\u00A0N.,\u00C2\u00A0and\u00C2\u00A0Grant,\u00C2\u00A0B.\u00C2\u00A0\u00C2\u00A02000.\u00C2\u00A0\u00C2\u00A0Volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0 in\u00C2\u00A0Per\u00C3\u00BA.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0VMS\u00C2\u00A0Deposits\u00C2\u00A0of\u00C2\u00A0Latin\u00C2\u00A0America.\u00C2\u00A0\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0R.\u00C2\u00A0Sherlock\u00C2\u00A0and\u00C2\u00A0M.A.V.\u00C2\u00A0Logan.\u00C2\u00A0 Geological\u00C2\u00A0Association\u00C2\u00A0of\u00C2\u00A0Canada,\u00C2\u00A0Mineral\u00C2\u00A0Deposits\u00C2\u00A0Division,\u00C2\u00A0Special\u00C2\u00A0Paper\u00C2\u00A0No.2.\u00C2\u00A0pp.\u00C2\u00A0423\u00E2\u0080\u0090 437.\u00C2\u00A0 Taylor,\u00C2\u00A0B.J.,\u00C2\u00A0Goodliffe,\u00C2\u00A0A.,\u00C2\u00A0Martinez,\u00C2\u00A0F.,\u00C2\u00A0and\u00C2\u00A0Het,\u00C2\u00A0R.\u00C2\u00A0\u00C2\u00A01995.\u00C2\u00A0\u00C2\u00A0Continental\u00C2\u00A0rifting\u00C2\u00A0and\u00C2\u00A0initial\u00C2\u00A0seafloor\u00C2\u00A0 spreading\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Woodlark\u00C2\u00A0Basin.\u00C2\u00A0\u00C2\u00A0Nature,\u00C2\u00A0374:\u00C2\u00A0534\u00E2\u0080\u0090537.\u00C2\u00A0 Tegart,\u00C2\u00A0P.,\u00C2\u00A0Allen,\u00C2\u00A0G.,\u00C2\u00A0Carstensen,\u00C2\u00A0A.\u00C2\u00A0\u00C2\u00A02000.\u00C2\u00A0\u00C2\u00A0Regional\u00C2\u00A0setting,\u00C2\u00A0stratigraphy,\u00C2\u00A0alteration\u00C2\u00A0and\u00C2\u00A0 mineralization\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Tambo\u00C2\u00A0Grande\u00C2\u00A0VMS\u00C2\u00A0district,\u00C2\u00A0Piura\u00C2\u00A0Department,\u00C2\u00A0Northern\u00C2\u00A0Per\u00C3\u00BA.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0 VMS\u00C2\u00A0Deposits\u00C2\u00A0of\u00C2\u00A0Latin\u00C2\u00A0America.\u00C2\u00A0\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0R.\u00C2\u00A0Sherlock\u00C2\u00A0and\u00C2\u00A0M.A.V.\u00C2\u00A0Logan.\u00C2\u00A0Geological\u00C2\u00A0 Association\u00C2\u00A0of\u00C2\u00A0Canada,\u00C2\u00A0Mineral\u00C2\u00A0Deposits\u00C2\u00A0Division,\u00C2\u00A0Special\u00C2\u00A0Paper\u00C2\u00A0No.2.\u00C2\u00A0pp.\u00C2\u00A0375\u00E2\u0080\u0090405.\u00C2\u00A0 \u00C2\u00A0 Tera,\u00C2\u00A0F.,\u00C2\u00A0and\u00C2\u00A0Wasserburg,\u00C2\u00A0G.J.\u00C2\u00A0\u00C2\u00A01972.\u00C2\u00A0\u00C2\u00A0U\u00E2\u0080\u0090Th\u00E2\u0080\u0090Pb\u00C2\u00A0systematics\u00C2\u00A0in\u00C2\u00A0three\u00C2\u00A0Apollo\u00C2\u00A014\u00C2\u00A0basalts\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0 problem\u00C2\u00A0of\u00C2\u00A0initial\u00C2\u00A0Pb\u00C2\u00A0in\u00C2\u00A0lunar\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0Earth\u00C2\u00A0and\u00C2\u00A0Planetary\u00C2\u00A0Science\u00C2\u00A0Letters,\u00C2\u00A014:\u00C2\u00A0281\u00E2\u0080\u0090304.\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 Page\u00C2\u00A081\u00C2\u00A0 Chapter\u00C2\u00A02\u00C2\u00A0 Page\u00C2\u00A082\u00C2\u00A0 Winter,\u00C2\u00A0L.S.,\u00C2\u00A0Tosdal,\u00C2\u00A0R.,\u00C2\u00A0Franklin,\u00C2\u00A0J.M.,\u00C2\u00A0Tegart,\u00C2\u00A0P.\u00C2\u00A0\u00C2\u00A02004.\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0Reconstructed\u00C2\u00A0Cretaceous\u00C2\u00A0 Depositional\u00C2\u00A0Setting\u00C2\u00A0for\u00C2\u00A0Giant\u00C2\u00A0Volcanogenic\u00C2\u00A0Massive\u00C2\u00A0Sulfide\u00C2\u00A0Deposits\u00C2\u00A0at\u00C2\u00A0Tambogrande,\u00C2\u00A0 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deflection\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Andes\u00C2\u00A0of\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0and\u00C2\u00A0Ecuador.\u00C2\u00A0\u00C2\u00A0Geological\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0America\u00C2\u00A0Annual\u00C2\u00A0 Meeting.\u00C2\u00A0\u00C2\u00A0Paper\u00C2\u00A0No.\u00C2\u00A0191\u00E2\u0080\u009014.\u00C2\u00A0 \u00C2\u00A0 White,\u00C2\u00A0J.D.L.,\u00C2\u00A0Smellie,\u00C2\u00A0J.L.,\u00C2\u00A0and\u00C2\u00A0Clague,\u00C2\u00A0D.A.\u00C2\u00A0\u00C2\u00A02003.\u00C2\u00A0\u00C2\u00A0Introduction:\u00C2\u00A0A\u00C2\u00A0deductive\u00C2\u00A0outline\u00C2\u00A0and\u00C2\u00A0topical\u00C2\u00A0 overview\u00C2\u00A0of\u00C2\u00A0subaqueous\u00C2\u00A0explosive\u00C2\u00A0volcanism.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0Explosive\u00C2\u00A0subaqueous\u00C2\u00A0volcanism.\u00C2\u00A0\u00C2\u00A0Edited\u00C2\u00A0 by\u00C2\u00A0J.D.L.\u00C2\u00A0White,\u00C2\u00A0J.L.\u00C2\u00A0Smellie,\u00C2\u00A0and\u00C2\u00A0D.A.\u00C2\u00A0Clague.\u00C2\u00A0\u00C2\u00A0American\u00C2\u00A0Geophysical\u00C2\u00A0Union\u00C2\u00A0Geophysical\u00C2\u00A0 Monograph\u00C2\u00A0140,\u00C2\u00A0pp.\u00C2\u00A01\u00E2\u0080\u009323.\u00C2\u00A0 \u00C2\u00A0 Vergara,\u00C2\u00A0M.,\u00C2\u00A0Levi,\u00C2\u00A0B.,\u00C2\u00A0Nystr\u00C3\u00B6m,\u00C2\u00A0J.O.,\u00C2\u00A0Cancino,\u00C2\u00A0A.\u00C2\u00A0\u00C2\u00A01995.\u00C2\u00A0\u00C2\u00A0Jurassic\u00C2\u00A0and\u00C2\u00A0Early\u00C2\u00A0Cretaceous\u00C2\u00A0island\u00C2\u00A0arc\u00C2\u00A0 volcanism,\u00C2\u00A0extension,\u00C2\u00A0and\u00C2\u00A0subsidence\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Coast\u00C2\u00A0Range\u00C2\u00A0of\u00C2\u00A0central\u00C2\u00A0Chile.\u00C2\u00A0\u00C2\u00A0Geological\u00C2\u00A0 Society\u00C2\u00A0of\u00C2\u00A0America\u00C2\u00A0Bulletin,\u00C2\u00A0107:\u00C2\u00A01427\u00E2\u0080\u00901440.\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A03.\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0Reconstructed\u00C2\u00A0Cretaceous\u00C2\u00A0Depositional\u00C2\u00A0Setting\u00C2\u00A0for\u00C2\u00A0Giant\u00C2\u00A0VMS\u00C2\u00A0Deposits\u00C2\u00A0at\u00C2\u00A0 Tambogrande,\u00C2\u00A0NW\u00C2\u00A0Per\u00C3\u00BA2\u00C2\u00A0 \u00C2\u00A0 3.1\u00C2\u00A0 Manuscript\u00C2\u00A0Status\u00C2\u00A0 A\u00C2\u00A0version\u00C2\u00A0of\u00C2\u00A0this\u00C2\u00A0chapter\u00C2\u00A0has\u00C2\u00A0been\u00C2\u00A0published.\u00C2\u00A0\u00C2\u00A0Only\u00C2\u00A0the\u00C2\u00A0abstract\u00C2\u00A0is\u00C2\u00A0provided\u00C2\u00A0here\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0 Copyright\u00C2\u00A0limitations.\u00C2\u00A0 3.2\u00C2\u00A0 Abstract\u00C2\u00A0 The\u00C2\u00A0Cretaceous\u00C2\u00A0Tambogrande\u00C2\u00A0volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0(VMS)\u00C2\u00A0deposits\u00C2\u00A0of\u00C2\u00A0northern\u00C2\u00A0 Per\u00C3\u00BA\u00C2\u00A0are\u00C2\u00A0amongst\u00C2\u00A0the\u00C2\u00A0largest\u00C2\u00A0Cu\u00E2\u0080\u0090Zn\u00E2\u0080\u0090Au\u00E2\u0080\u0090Ag\u00C2\u00A0bimodal\u00E2\u0080\u0090mafic\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0world.\u00C2\u00A0\u00C2\u00A0There\u00C2\u00A0are\u00C2\u00A0 three\u00C2\u00A0known\u00C2\u00A0deposits\u00C2\u00A0each\u00C2\u00A0with\u00C2\u00A0approximately\u00C2\u00A0100\u00C2\u00A0million\u00C2\u00A0metric\u00C2\u00A0tons\u00C2\u00A0(Mt)\u00C2\u00A0of\u00C2\u00A0pyrite\u00E2\u0080\u0090rich\u00C2\u00A0 massive\u00C2\u00A0sulphide.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0deposits\u00C2\u00A0are\u00C2\u00A0intimately\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0dacite\u00C2\u00A0lava\u00C2\u00A0dome\u00C2\u00A0complexes\u00C2\u00A0and\u00C2\u00A0 were\u00C2\u00A0deposited\u00C2\u00A0within\u00C2\u00A0steep\u00E2\u0080\u0090sided\u00C2\u00A0basins\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0seafloor.\u00C2\u00A0\u00C2\u00A0Reconstructed\u00C2\u00A0seafloor\u00C2\u00A0 paleomorphological\u00C2\u00A0models\u00C2\u00A0indicate\u00C2\u00A0sulphide\u00C2\u00A0deposition\u00C2\u00A0was\u00C2\u00A0focussed\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0deepest\u00C2\u00A0parts\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0basins.\u00C2\u00A0\u00C2\u00A0Sulphide\u00C2\u00A0deposition\u00C2\u00A0accompanied\u00C2\u00A0syn\u00E2\u0080\u0090volcanic\u00C2\u00A0faulting\u00C2\u00A0and\u00C2\u00A0episodic\u00C2\u00A0dacitic\u00C2\u00A0and\u00C2\u00A0 basaltic\u00C2\u00A0eruptions.\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0series\u00C2\u00A0of\u00C2\u00A0time\u00E2\u0080\u0090stratigraphic\u00C2\u00A0horizons\u00C2\u00A0are\u00C2\u00A0noted\u00C2\u00A0at\u00C2\u00A0TG1\u00C2\u00A0and\u00C2\u00A0TG3\u00C2\u00A0and\u00C2\u00A0mark\u00C2\u00A0 stages\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0development\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0complex\u00C2\u00A0and\u00C2\u00A0massive\u00C2\u00A0sulphides.\u00C2\u00A0\u00C2\u00A0There\u00C2\u00A0is\u00C2\u00A0only\u00C2\u00A0limited\u00C2\u00A0 evidence\u00C2\u00A0for\u00C2\u00A0replacement\u00C2\u00A0of\u00C2\u00A0host\u00C2\u00A0rocks\u00C2\u00A0during\u00C2\u00A0formation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Tambogrande\u00C2\u00A0deposits,\u00C2\u00A0unlike\u00C2\u00A0 many\u00C2\u00A0other\u00C2\u00A0large\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0deposits\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0resulted\u00C2\u00A0from\u00C2\u00A0 focused\u00C2\u00A0hydrothermal\u00C2\u00A0fluid\u00C2\u00A0flow\u00C2\u00A0along\u00C2\u00A0syn\u00E2\u0080\u0090volcanic\u00C2\u00A0faults\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0deposition\u00C2\u00A0of\u00C2\u00A0sulphides\u00C2\u00A0within\u00C2\u00A0 relatively\u00C2\u00A0deep\u00C2\u00A0and\u00C2\u00A0restricted\u00C2\u00A0basins.\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0depressions\u00C2\u00A0of\u00C2\u00A0up\u00C2\u00A0to\u00C2\u00A0several\u00C2\u00A0hundred\u00C2\u00A0metres\u00C2\u00A0deep,\u00C2\u00A0 the\u00C2\u00A0result\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0structural\u00C2\u00A0and\u00C2\u00A0volcanological\u00C2\u00A0setting,\u00C2\u00A0acted\u00C2\u00A0as\u00C2\u00A0efficient\u00C2\u00A0\u00E2\u0080\u0098traps\u00E2\u0080\u0099\u00C2\u00A0for\u00C2\u00A0sulphide\u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 2 A version of this chapter has been published. Winter, L.S., Tosdal, R., Franklin, J.M., Tegart, P. 2004. A Reconstructed Cretaceous Depositional Setting for Giant Volcanogenic Massive Sulfide Deposits at Tambogrande, Northwestern Per\u00C3\u00BA. In Special Publication 11 - Andean Metallogeny: New Discoveries, Concepts, and Updates. Edited by R.H. Sillitoe, J.Perello, and C.Vidal. Society of Economic Geologists, pp. 319-340. Chapter\u00C2\u00A03\u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A083\u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A03\u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A084\u00C2\u00A0 \u00C2\u00A0 deposition\u00C2\u00A0and\u00C2\u00A0also\u00C2\u00A0were\u00C2\u00A0also\u00C2\u00A0important\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0preservation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0sulphide,\u00C2\u00A0as\u00C2\u00A0they\u00C2\u00A0acted\u00C2\u00A0to\u00C2\u00A0 shield\u00C2\u00A0the\u00C2\u00A0accumulations\u00C2\u00A0from\u00C2\u00A0potential\u00C2\u00A0submarine\u00C2\u00A0oxidation\u00C2\u00A0and\u00C2\u00A0weathering.\u00C2\u00A0\u00C2\u00A0Steep\u00C2\u00A0basins\u00C2\u00A0and\u00C2\u00A0 episodic\u00C2\u00A0bimodal\u00C2\u00A0eruptions\u00C2\u00A0are\u00C2\u00A0key\u00C2\u00A0geologic\u00C2\u00A0attributes\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0depositional\u00C2\u00A0setting\u00C2\u00A0at\u00C2\u00A0 Tambogrande\u00C2\u00A0and\u00C2\u00A0may\u00C2\u00A0be\u00C2\u00A0necessary\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0formation\u00C2\u00A0of\u00C2\u00A0anomalously\u00C2\u00A0large\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0 volcanic\u00C2\u00A0rock\u00E2\u0080\u0090dominated\u00C2\u00A0environment.\u00C2\u00A0 Chapter\u00C2\u00A04.\u00C2\u00A0\u00C2\u00A0Volcanic\u00C2\u00A0Rock\u00C2\u00A0Geochemistry\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0Geodynamic\u00C2\u00A0Setting\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0Deposits\u00C2\u00A0at\u00C2\u00A0 Tambogrande,\u00C2\u00A0Per\u00C3\u00BA3\u00C2\u00A0 4.1\u00C2\u00A0 Overview\u00C2\u00A0 \u00E2\u0080\u0098Giant\u00E2\u0080\u0099\u00C2\u00A0volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0(VMS)\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Tambogrande\u00C2\u00A0area\u00C2\u00A0of\u00C2\u00A0 northwestern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0occur\u00C2\u00A0along\u00C2\u00A0a\u00C2\u00A0single\u00C2\u00A0time\u00E2\u0080\u0090stratigraphic\u00C2\u00A0horizon\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0ca\u00C2\u00A0105\u00C2\u00A0Ma\u00C2\u00A0Cerro\u00C2\u00A0 San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation,\u00C2\u00A0the\u00C2\u00A0lowermost\u00C2\u00A0volcanic\u00C2\u00A0sequence\u00C2\u00A0deposited\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0arc\u00E2\u0080\u0090 rift\u00C2\u00A0basin.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0is\u00C2\u00A0part\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0larger\u00C2\u00A0series\u00C2\u00A0of\u00C2\u00A0segmented,\u00C2\u00A0continental\u00C2\u00A0margin\u00C2\u00A0rift\u00C2\u00A0 basins\u00C2\u00A0extending\u00C2\u00A0from\u00C2\u00A0southwestern\u00C2\u00A0Ecuador\u00C2\u00A0and\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0Peruvian\u00C2\u00A0coast.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0three\u00C2\u00A0known\u00C2\u00A0 deposits\u00C2\u00A0(TG1:\u00C2\u00A0109\u00C2\u00A0Mt\u00C2\u00A0grading\u00C2\u00A01.6%\u00C2\u00A0Cu,\u00C2\u00A01.0%\u00C2\u00A0Zn,\u00C2\u00A00.5\u00C2\u00A0g/t\u00C2\u00A0Au\u00C2\u00A0and\u00C2\u00A022\u00C2\u00A0g/t\u00C2\u00A0Ag,\u00C2\u00A0plus\u00C2\u00A016.7\u00C2\u00A0Mt\u00C2\u00A0grading\u00C2\u00A0 3.5\u00C2\u00A0g/t\u00C2\u00A0Au\u00C2\u00A0and\u00C2\u00A064\u00C2\u00A0g/t\u00C2\u00A0Ag\u00C2\u00A0in\u00C2\u00A0oxide\u00C2\u00A0ore;\u00C2\u00A0TG3:\u00C2\u00A082\u00C2\u00A0Mt\u00C2\u00A0grading\u00C2\u00A01.0%\u00C2\u00A0Cu,\u00C2\u00A01.4%\u00C2\u00A0Zn,\u00C2\u00A00.8\u00C2\u00A0g/t\u00C2\u00A0Au\u00C2\u00A0and\u00C2\u00A025\u00C2\u00A0 g/t\u00C2\u00A0Ag,\u00C2\u00A0and\u00C2\u00A0B5:\u00C2\u00A0resource\u00C2\u00A0not\u00C2\u00A0defined)\u00C2\u00A0constitute\u00C2\u00A0the\u00C2\u00A0most\u00C2\u00A0significant\u00C2\u00A0VMS\u00C2\u00A0camp\u00C2\u00A0in\u00C2\u00A0South\u00C2\u00A0 America.\u00C2\u00A0 A\u00C2\u00A0lithogeochemical\u00C2\u00A0study\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0sequence\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0illustrates\u00C2\u00A0that\u00C2\u00A0 all\u00C2\u00A0volcanic\u00C2\u00A0units\u00C2\u00A0sampled\u00C2\u00A0are\u00C2\u00A0\u00E2\u0080\u0098arc\u00E2\u0080\u0090related\u00E2\u0080\u0099\u00C2\u00A0and\u00C2\u00A0display\u00C2\u00A0prominent\u00C2\u00A0negative\u00C2\u00A0Nb\u00C2\u00A0anomalies\u00C2\u00A0 relative\u00C2\u00A0to\u00C2\u00A0Th\u00C2\u00A0and\u00C2\u00A0Nb\u00C2\u00A0on\u00C2\u00A0primitive\u00E2\u0080\u0090mantle\u00C2\u00A0normalized\u00C2\u00A0trace\u00C2\u00A0element\u00C2\u00A0plots.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0VMS\u00E2\u0080\u0090hosting\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0is\u00C2\u00A0a\u00C2\u00A0bimodal\u00C2\u00A0sequence\u00C2\u00A0dominated\u00C2\u00A0by\u00C2\u00A0basaltic\u00C2\u00A0lava\u00C2\u00A0flows\u00C2\u00A0of\u00C2\u00A0 transitional\u00C2\u00A0to\u00C2\u00A0mildly\u00C2\u00A0calc\u00E2\u0080\u0090alkaline\u00C2\u00A0affinity\u00C2\u00A0defined\u00C2\u00A0by\u00C2\u00A0moderate\u00C2\u00A0REE\u00C2\u00A0abundances\u00C2\u00A0(YbN\u00C2\u00A0=\u00C2\u00A04\u00E2\u0080\u009312),\u00C2\u00A0 moderate\u00C2\u00A0LREE/HREE\u00C2\u00A0fractionation\u00C2\u00A0[(La/Yb)N\u00C2\u00A0=\u00C2\u00A00.6\u00E2\u0080\u00937.3],\u00C2\u00A0low\u00E2\u0080\u0090moderate\u00C2\u00A0Zr/Y\u00C2\u00A0ratios\u00C2\u00A0(1.5\u00E2\u0080\u00905.3),\u00C2\u00A0and\u00C2\u00A0 negative\u00C2\u00A0HFSE\u00C2\u00A0(high\u00C2\u00A0field\u00C2\u00A0strength\u00C2\u00A0element)\u00C2\u00A0anomalies\u00C2\u00A0(e.g.,\u00C2\u00A0Nb/Nb*\u00C2\u00A0=\u00C2\u00A00.1\u00E2\u0080\u00930.5;\u00C2\u00A0Zr\u00C2\u00A0and\u00C2\u00A0Hf\u00C2\u00A0display\u00C2\u00A0 slight\u00C2\u00A0depletions).\u00C2\u00A0\u00C2\u00A0Felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0this\u00C2\u00A0formation\u00C2\u00A0are\u00C2\u00A0M\u00E2\u0080\u0090type\u00C2\u00A0(i.e.,\u00C2\u00A0mantle\u00E2\u0080\u0090derived;\u00C2\u00A0low\u00C2\u00A0 Nb,\u00C2\u00A0Y)\u00C2\u00A0and\u00C2\u00A0are\u00C2\u00A0comparable\u00C2\u00A0in\u00C2\u00A0geochemical\u00C2\u00A0affinity\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0basalt\u00C2\u00A0regarding\u00C2\u00A0LREE\u00E2\u0080\u0090profiles\u00C2\u00A0 [(La/Yb)N\u00C2\u00A0=\u00C2\u00A01.2\u00E2\u0080\u00906.6],\u00C2\u00A0Zr/Y\u00C2\u00A0ratios\u00C2\u00A0(3.0\u00E2\u0080\u00907.1),\u00C2\u00A0and\u00C2\u00A0negative\u00C2\u00A0Nb\u00C2\u00A0anomalies\u00C2\u00A0(Nb/Nb*\u00C2\u00A0=\u00C2\u00A00.1\u00E2\u0080\u00930.3).\u00C2\u00A0\u00C2\u00A0 However,\u00C2\u00A0the\u00C2\u00A0felsic\u00C2\u00A0rocks\u00C2\u00A0differ\u00C2\u00A0in\u00C2\u00A0having\u00C2\u00A0higher\u00C2\u00A0REE\u00C2\u00A0abundances\u00C2\u00A0(YbN\u00C2\u00A0=\u00C2\u00A010\u00E2\u0080\u009024),\u00C2\u00A0some\u00C2\u00A0HFSE\u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 3 A version of this chapter will be submitted for publication. Winter, L.S. and Tosdal, R., Volcanic Rock Geochemistry and the Geodynamic Setting of VMS Deposits at Tambogrande, Per\u00C3\u00BA. Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 85\u00C2\u00A0 \u00C2\u00A0 enrichment\u00C2\u00A0(Zr/Zr*\u00C2\u00A0=\u00C2\u00A01.0\u00E2\u0080\u00932.2;\u00C2\u00A0Hf/Hf*\u00C2\u00A0=\u00C2\u00A01.1\u00E2\u0080\u00932.5),\u00C2\u00A0and\u00C2\u00A0pronounced\u00C2\u00A0negative\u00C2\u00A0Ti\u00C2\u00A0(Ti/Ti*=\u00C2\u00A00.1\u00E2\u0080\u00900.2)\u00C2\u00A0 and\u00C2\u00A0Eu\u00C2\u00A0anomalies\u00C2\u00A0(Eu/Eu*\u00C2\u00A0=\u00C2\u00A00.4\u00E2\u0080\u00930.9).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0rhyolites\u00C2\u00A0range\u00C2\u00A0from\u00C2\u00A0FII\u00C2\u00A0to\u00C2\u00A0FIII\u00E2\u0080\u0090type.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Overlying\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation,\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation\u00C2\u00A0comprises\u00C2\u00A0a\u00C2\u00A0 uniform\u00C2\u00A0sequence\u00C2\u00A0of\u00C2\u00A0coarse\u00C2\u00A0feldspar\u00C2\u00A0porphyritic\u00C2\u00A0basalt\u00C2\u00A0flows\u00C2\u00A0and\u00C2\u00A0breccia\u00C2\u00A0with\u00C2\u00A0transitional\u00C2\u00A0 affinities.\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0are\u00C2\u00A0characterized\u00C2\u00A0by\u00C2\u00A0negligible\u00C2\u00A0LREE/HREE\u00C2\u00A0fractionation\u00C2\u00A0[(La/Yb)N\u00C2\u00A0=\u00C2\u00A00.4\u00E2\u0080\u00901.6]\u00C2\u00A0 and\u00C2\u00A0low\u00C2\u00A0Zr/Y\u00C2\u00A0ratios\u00C2\u00A0(1.4\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A02.8).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0uppermost\u00C2\u00A0volcanic\u00C2\u00A0sequence,\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation,\u00C2\u00A0is\u00C2\u00A0a\u00C2\u00A0 bimodal\u00C2\u00A0sequence\u00C2\u00A0characterized\u00C2\u00A0by\u00C2\u00A0transitional\u00C2\u00A0to\u00C2\u00A0tholeiitic\u00C2\u00A0mafic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0[(La/Yb)N\u00C2\u00A0=\u00C2\u00A00.5\u00E2\u0080\u0090 2.6,\u00C2\u00A0Zr/Y\u00C2\u00A0=\u00C2\u00A01.3\u00E2\u0080\u00903.3].\u00C2\u00A0\u00C2\u00A0M\u00E2\u0080\u0090type\u00C2\u00A0rhyolites\u00C2\u00A0[(La/Yb)N\u00C2\u00A0=\u00C2\u00A00.5\u00E2\u0080\u00902.6,\u00C2\u00A0Zr/Y\u00C2\u00A0=\u00C2\u00A01.3\u00E2\u0080\u00903.3]\u00C2\u00A0are\u00C2\u00A0very\u00C2\u00A0similar\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0but\u00C2\u00A0are\u00C2\u00A0mostly\u00C2\u00A0FIV\u00E2\u0080\u0090like.\u00C2\u00A0 There\u00C2\u00A0are\u00C2\u00A0only\u00C2\u00A0subtle\u00C2\u00A0variations\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0petrochemistry\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0arc\u00C2\u00A0volcanic\u00C2\u00A0sequence\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0 Lancones\u00C2\u00A0basin\u00C2\u00A0which\u00C2\u00A0favour\u00C2\u00A0VMS\u00C2\u00A0formation\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0early\u00C2\u00A0rift,\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation,\u00C2\u00A0 which\u00C2\u00A0include:\u00C2\u00A0(i)\u00C2\u00A0Evolution\u00C2\u00A0from\u00C2\u00A0mildly\u00C2\u00A0calc\u00E2\u0080\u0090alkaline\u00C2\u00A0to\u00C2\u00A0tholeiitic\u00C2\u00A0affinities;\u00C2\u00A0\u00C2\u00A0this\u00C2\u00A0possibly\u00C2\u00A0reflects\u00C2\u00A0 a\u00C2\u00A0depletion\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0mantle\u00C2\u00A0source\u00C2\u00A0with\u00C2\u00A0time.\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0relatively\u00C2\u00A0static\u00C2\u00A0mantle\u00C2\u00A0wedge\u00C2\u00A0with\u00C2\u00A0limited\u00C2\u00A0 replenishment\u00C2\u00A0of\u00C2\u00A0fertile\u00C2\u00A0asthensophere\u00C2\u00A0during\u00C2\u00A0waning\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0extensional\u00C2\u00A0phase\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0rift\u00C2\u00A0event\u00C2\u00A0 may\u00C2\u00A0be\u00C2\u00A0responsible.\u00C2\u00A0\u00C2\u00A0Moreover,\u00C2\u00A0the\u00C2\u00A0absence\u00C2\u00A0of\u00C2\u00A0MORB\u00E2\u0080\u0090type\u00C2\u00A0lavas\u00C2\u00A0suggests\u00C2\u00A0the\u00C2\u00A0rift\u00C2\u00A0basin\u00C2\u00A0did\u00C2\u00A0not\u00C2\u00A0 evolve\u00C2\u00A0to\u00C2\u00A0back\u00E2\u0080\u0090arc\u00C2\u00A0rifting.\u00C2\u00A0\u00C2\u00A0VMS\u00C2\u00A0formation\u00C2\u00A0was\u00C2\u00A0more\u00C2\u00A0likely\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0early\u00C2\u00A0stages\u00C2\u00A0of\u00C2\u00A0arc\u00C2\u00A0volcanism\u00C2\u00A0 during\u00C2\u00A0the\u00C2\u00A0initial\u00C2\u00A0rifting\u00C2\u00A0and\u00C2\u00A0period\u00C2\u00A0of\u00C2\u00A0maximum\u00C2\u00A0extension;\u00C2\u00A0\u00C2\u00A0(ii)\u00C2\u00A0Average\u00C2\u00A0basalt\u00C2\u00A0composition\u00C2\u00A0is\u00C2\u00A0 \u00E2\u0080\u0098less\u00C2\u00A0fractionated\u00E2\u0080\u0099\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation,\u00C2\u00A0with\u00C2\u00A0higher\u00C2\u00A0MgO,\u00C2\u00A0Ni,\u00C2\u00A0Cr,\u00C2\u00A0than\u00C2\u00A0basalt\u00C2\u00A0in\u00C2\u00A0 the\u00C2\u00A0overlying\u00C2\u00A0Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0and\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0formations.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0may\u00C2\u00A0be\u00C2\u00A0related\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0presence\u00C2\u00A0of\u00C2\u00A0 thinner\u00C2\u00A0ocean\u00C2\u00A0crust\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0basin\u00C2\u00A0during\u00C2\u00A0the\u00C2\u00A0early\u00C2\u00A0stages\u00C2\u00A0of\u00C2\u00A0rifting\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0concomitant\u00C2\u00A0more\u00C2\u00A0 rapid\u00C2\u00A0transfer\u00C2\u00A0of\u00C2\u00A0basaltic\u00C2\u00A0magma\u00C2\u00A0to\u00C2\u00A0surface.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0reflects\u00C2\u00A0the\u00C2\u00A0greater\u00C2\u00A0heat\u00C2\u00A0transfer\u00C2\u00A0to\u00C2\u00A0shallow\u00C2\u00A0 crustal\u00C2\u00A0levels\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0early\u00C2\u00A0stages\u00C2\u00A0of\u00C2\u00A0arc\u00C2\u00A0volcanism,\u00C2\u00A0is\u00C2\u00A0consistent\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0timing\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0 formation\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin;\u00C2\u00A0\u00C2\u00A0and\u00C2\u00A0(iii)\u00C2\u00A0M\u00E2\u0080\u0090type\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0have\u00C2\u00A0lower\u00C2\u00A0HFSE\u00C2\u00A0and\u00C2\u00A0REE\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 86\u00C2\u00A0 \u00C2\u00A0 contents\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0than\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0the\u00C2\u00A0 immediate\u00C2\u00A0vicinity\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0VMS\u00C2\u00A0deposits,\u00C2\u00A0rhyolite\u00C2\u00A0does\u00C2\u00A0not\u00C2\u00A0define\u00C2\u00A0fractionation\u00C2\u00A0trends\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0 mafic\u00C2\u00A0rocks,\u00C2\u00A0rather,\u00C2\u00A0the\u00C2\u00A0variable\u00C2\u00A0REE\u00C2\u00A0and\u00C2\u00A0HFSE\u00C2\u00A0ratios\u00C2\u00A0indicate\u00C2\u00A0contamination\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0mafic\u00E2\u0080\u0090 derived\u00C2\u00A0lavas\u00C2\u00A0with\u00C2\u00A0an\u00C2\u00A0incompatible\u00C2\u00A0element\u00C2\u00A0enriched\u00C2\u00A0source\u00C2\u00A0(i.e.,\u00C2\u00A0continental\u00C2\u00A0crust).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0 felsic\u00C2\u00A0magmas\u00C2\u00A0were\u00C2\u00A0likely\u00C2\u00A0partial\u00C2\u00A0melts\u00C2\u00A0of\u00C2\u00A0upper\u00C2\u00A0crustal\u00C2\u00A0portions\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0juvenile\u00C2\u00A0arc,\u00C2\u00A0or\u00C2\u00A0were\u00C2\u00A0 primary\u00C2\u00A0melts\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0mantle\u00E2\u0080\u0090wedge\u00C2\u00A0that\u00C2\u00A0assimilated\u00C2\u00A0older\u00C2\u00A0crust.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0ore\u00E2\u0080\u0090associated\u00C2\u00A0felsic\u00C2\u00A0 volcanic\u00C2\u00A0rocks\u00C2\u00A0typify\u00C2\u00A0the\u00C2\u00A0generally\u00C2\u00A0more\u00C2\u00A0prospective\u00C2\u00A0FII\u00C2\u00A0to\u00C2\u00A0FIII\u00E2\u0080\u0090type\u00C2\u00A0rhyolites,\u00C2\u00A0though\u00C2\u00A0with\u00C2\u00A0 slightly\u00C2\u00A0lower\u00C2\u00A0average\u00C2\u00A0HFSE\u00C2\u00A0and\u00C2\u00A0REE\u00C2\u00A0contents.\u00C2\u00A0\u00C2\u00A0Rhyolite\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0VMS\u00E2\u0080\u0090barren\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0 is\u00C2\u00A0dominantly\u00C2\u00A0FIV\u00C2\u00A0type.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0suggests\u00C2\u00A0the\u00C2\u00A0petrogenesis\u00C2\u00A0of\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0 Phanerozoic\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0is\u00C2\u00A0not\u00C2\u00A0substantially\u00C2\u00A0different\u00C2\u00A0than\u00C2\u00A0that\u00C2\u00A0of\u00C2\u00A0some\u00C2\u00A0Archean\u00C2\u00A0VMS\u00C2\u00A0 systems.\u00C2\u00A0 The\u00C2\u00A0ocean\u00C2\u00A0arc\u00E2\u0080\u0090type\u00C2\u00A0geochemical\u00C2\u00A0affinities\u00C2\u00A0which\u00C2\u00A0define\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0 are\u00C2\u00A0unusual\u00C2\u00A0considering\u00C2\u00A0the\u00C2\u00A0continental\u00C2\u00A0margin\u00C2\u00A0geodynamic\u00C2\u00A0setting,\u00C2\u00A0where\u00C2\u00A0continental\u00C2\u00A0rift\u00C2\u00A0or\u00C2\u00A0 continental\u00C2\u00A0back\u00E2\u0080\u0090arc\u00C2\u00A0rift\u00C2\u00A0affinities\u00C2\u00A0might\u00C2\u00A0be\u00C2\u00A0expected.\u00C2\u00A0\u00C2\u00A0Since\u00C2\u00A0the\u00C2\u00A0arc\u00C2\u00A0does\u00C2\u00A0not\u00C2\u00A0appear\u00C2\u00A0to\u00C2\u00A0have\u00C2\u00A0 had\u00C2\u00A0a\u00C2\u00A0protracted\u00C2\u00A0history\u00C2\u00A0of\u00C2\u00A0extension\u00C2\u00A0and\u00C2\u00A0did\u00C2\u00A0not\u00C2\u00A0fully\u00C2\u00A0evolve\u00C2\u00A0to\u00C2\u00A0a\u00C2\u00A0back\u00E2\u0080\u0090arc,\u00C2\u00A0the\u00C2\u00A0pre\u00E2\u0080\u0090Andean\u00C2\u00A0 (Early\u00C2\u00A0Cretaceous)\u00C2\u00A0continental\u00C2\u00A0crust\u00C2\u00A0must\u00C2\u00A0have\u00C2\u00A0been\u00C2\u00A0relatively\u00C2\u00A0thin\u00C2\u00A0prior\u00C2\u00A0to\u00C2\u00A0arc\u00C2\u00A0magmatism.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Mantle\u00E2\u0080\u0090derived\u00C2\u00A0magmas\u00C2\u00A0traversed\u00C2\u00A0the\u00C2\u00A0attenuated\u00C2\u00A0crust\u00C2\u00A0and\u00C2\u00A0preserved\u00C2\u00A0their\u00C2\u00A0relatively\u00C2\u00A0 immature\u00C2\u00A0island\u00C2\u00A0arc\u00C2\u00A0geochemical\u00C2\u00A0characteristics.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 4.2\u00C2\u00A0 Introduction\u00C2\u00A0 Detailed\u00C2\u00A0volcanic\u00C2\u00A0rock\u00C2\u00A0geochemical\u00C2\u00A0studies\u00C2\u00A0in\u00C2\u00A0ancient\u00C2\u00A0volcanic\u00C2\u00A0settings\u00C2\u00A0are\u00C2\u00A0used\u00C2\u00A0to\u00C2\u00A0 understand\u00C2\u00A0the\u00C2\u00A0petrogenesis\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0volcanic\u00C2\u00A0suite\u00C2\u00A0and\u00C2\u00A0in\u00C2\u00A0turn\u00C2\u00A0can\u00C2\u00A0determine\u00C2\u00A0the\u00C2\u00A0relative\u00C2\u00A0 prospectivity\u00C2\u00A0to\u00C2\u00A0host\u00C2\u00A0volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0(VMS)\u00C2\u00A0mineralization\u00C2\u00A0(Lesher\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01986;\u00C2\u00A0 Swinden\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01997;\u00C2\u00A0Lentz,\u00C2\u00A01998;\u00C2\u00A0Bailes\u00C2\u00A0and\u00C2\u00A0Galley,\u00C2\u00A01999;\u00C2\u00A0Barrett\u00C2\u00A0and\u00C2\u00A0MacLean,\u00C2\u00A01999;\u00C2\u00A0Piercey\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 87\u00C2\u00A0 \u00C2\u00A0 et\u00C2\u00A0al.,\u00C2\u00A02001).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0However,\u00C2\u00A0studies\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0tectonic\u00C2\u00A0history\u00C2\u00A0of\u00C2\u00A0VMS\u00E2\u0080\u0090hosting\u00C2\u00A0terranes\u00C2\u00A0are\u00C2\u00A0hindered\u00C2\u00A0in\u00C2\u00A0 some\u00C2\u00A0ancient\u00C2\u00A0successions\u00C2\u00A0by\u00C2\u00A0tectonism,\u00C2\u00A0which\u00C2\u00A0has\u00C2\u00A0complicated\u00C2\u00A0elucidation\u00C2\u00A0of\u00C2\u00A0geologic\u00C2\u00A0events.\u00C2\u00A0\u00C2\u00A0 Nonetheless,\u00C2\u00A0in\u00C2\u00A0many\u00C2\u00A0VMS\u00C2\u00A0districts\u00C2\u00A0there\u00C2\u00A0is\u00C2\u00A0strong\u00C2\u00A0petrochemical\u00C2\u00A0evidence\u00C2\u00A0to\u00C2\u00A0support\u00C2\u00A0a\u00C2\u00A0spatial\u00C2\u00A0 relationship\u00C2\u00A0between\u00C2\u00A0extensional\u00C2\u00A0arc\u00C2\u00A0geodynamics\u00C2\u00A0and\u00C2\u00A0VMS\u00C2\u00A0formation\u00C2\u00A0(e.g.,\u00C2\u00A0Swinden,\u00C2\u00A01991;\u00C2\u00A0 Lentz,\u00C2\u00A01998;\u00C2\u00A0Piercey,\u00C2\u00A02007).\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0link\u00C2\u00A0is\u00C2\u00A0based\u00C2\u00A0largely\u00C2\u00A0on\u00C2\u00A0volcanic\u00C2\u00A0rock\u00C2\u00A0lithogeochemistry\u00C2\u00A0and\u00C2\u00A0 anologies\u00C2\u00A0to\u00C2\u00A0recent\u00C2\u00A0volcanic\u00C2\u00A0rock\u00C2\u00A0suites\u00C2\u00A0in\u00C2\u00A0modern\u00C2\u00A0settings.\u00C2\u00A0 The\u00C2\u00A0Cretaceous\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0is\u00C2\u00A0a\u00C2\u00A0relatively\u00C2\u00A0young\u00C2\u00A0volcanic\u00C2\u00A0terrane\u00C2\u00A0compared\u00C2\u00A0with\u00C2\u00A0most\u00C2\u00A0 other\u00C2\u00A0VMS\u00E2\u0080\u0090bearing\u00C2\u00A0terrains,\u00C2\u00A0and\u00C2\u00A0hence\u00C2\u00A0its\u00C2\u00A0geodynamic\u00C2\u00A0framework\u00C2\u00A0is\u00C2\u00A0relatively\u00C2\u00A0well\u00C2\u00A0understood.\u00C2\u00A0\u00C2\u00A0 Plate\u00C2\u00A0tectonic\u00C2\u00A0models\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0South\u00C2\u00A0American\u00C2\u00A0continent\u00C2\u00A0during\u00C2\u00A0the\u00C2\u00A0Cretaceous\u00C2\u00A0(e.g.,\u00C2\u00A0Scotese,\u00C2\u00A0 1991)\u00C2\u00A0and\u00C2\u00A0tectonic\u00C2\u00A0evolution\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Andes\u00C2\u00A0in\u00C2\u00A0particular\u00C2\u00A0(Benavides\u00E2\u0080\u0090C\u00C3\u00A1ceres,\u00C2\u00A01999;\u00C2\u00A0Jaillard\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A0 2000)\u00C2\u00A0are\u00C2\u00A0relatively\u00C2\u00A0well\u00C2\u00A0constrained.\u00C2\u00A0\u00C2\u00A0Stratigraphic\u00C2\u00A0and\u00C2\u00A0geochronological\u00C2\u00A0control\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0 volcanic\u00C2\u00A0successions\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0is\u00C2\u00A0also\u00C2\u00A0well\u00C2\u00A0established\u00C2\u00A0(Jaillard\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01999;\u00C2\u00A0Chap.\u00C2\u00A02).\u00C2\u00A0\u00C2\u00A0 At\u00C2\u00A0Tambogrande,\u00C2\u00A0arc\u00E2\u0080\u0090related\u00C2\u00A0rifting\u00C2\u00A0and\u00C2\u00A0volcanism\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A0continental\u00C2\u00A0margin\u00C2\u00A0is\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0 VMS\u00C2\u00A0formation.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0chapter\u00C2\u00A0provides\u00C2\u00A0a\u00C2\u00A0baseline\u00C2\u00A0whole\u00C2\u00A0rock\u00C2\u00A0lithogeochemical\u00C2\u00A0survey\u00C2\u00A0for\u00C2\u00A0 volcanic\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0and\u00C2\u00A0a\u00C2\u00A0detailed\u00C2\u00A0chemostratigraphic\u00C2\u00A0model\u00C2\u00A0for\u00C2\u00A0volcanic\u00C2\u00A0 lithologies\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0at\u00C2\u00A0Tambogrande.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0is\u00C2\u00A0located\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0coastal\u00C2\u00A0regional\u00C2\u00A0of\u00C2\u00A0northwestern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0and\u00C2\u00A0extends\u00C2\u00A0into\u00C2\u00A0 southwestern\u00C2\u00A0Ecuador.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0basin\u00C2\u00A0represents\u00C2\u00A0one\u00C2\u00A0of\u00C2\u00A0several\u00C2\u00A0marginal\u00C2\u00A0rift\u00C2\u00A0basins\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0 Peruvian\u00C2\u00A0continental\u00C2\u00A0margin\u00C2\u00A0that\u00C2\u00A0are\u00C2\u00A0host\u00C2\u00A0to\u00C2\u00A0numerous\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0(Fig.\u00C2\u00A04.1).\u00C2\u00A0\u00C2\u00A0However,\u00C2\u00A0the\u00C2\u00A0 Lancones\u00C2\u00A0basin\u00C2\u00A0hosts\u00C2\u00A0the\u00C2\u00A0most\u00C2\u00A0significant\u00C2\u00A0of\u00C2\u00A0all\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Andes\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0(Fig.\u00C2\u00A0 4.2).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0Tambogrande\u00C2\u00A0district\u00C2\u00A0(Injoque\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01979;\u00C2\u00A0Tegart\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02000;\u00C2\u00A0Chapter\u00C2\u00A02)\u00C2\u00A0is\u00C2\u00A0defined\u00C2\u00A0 by\u00C2\u00A0three\u00C2\u00A0anomalously\u00C2\u00A0large\u00C2\u00A0(~100\u00C2\u00A0Mt)\u00C2\u00A0base\u00E2\u0080\u0090\u00C2\u00A0and\u00C2\u00A0precious\u00E2\u0080\u0090metal\u00E2\u0080\u0090bearing\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0(Chap.\u00C2\u00A0 1).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0deposits\u00C2\u00A0are\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0upper\u00C2\u00A03%\u00C2\u00A0of\u00C2\u00A0all\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0of\u00C2\u00A0their\u00C2\u00A0type\u00C2\u00A0globally\u00C2\u00A0in\u00C2\u00A0terms\u00C2\u00A0of\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 88\u00C2\u00A0 \u00C2\u00A0 total\u00C2\u00A0metal\u00C2\u00A0content\u00C2\u00A0(Franklin\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02005)\u00C2\u00A0and\u00C2\u00A0can\u00C2\u00A0be\u00C2\u00A0classified\u00C2\u00A0as\u00C2\u00A0bimodal\u00C2\u00A0mafic\u00C2\u00A0type\u00C2\u00A0according\u00C2\u00A0 to\u00C2\u00A0Barrie\u00C2\u00A0and\u00C2\u00A0Hannington\u00C2\u00A0(1999).\u00C2\u00A0\u00C2\u00A0Analogous\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0are\u00C2\u00A0of\u00C2\u00A0Archean\u00C2\u00A0age\u00C2\u00A0(e.g.,\u00C2\u00A0Noranda,\u00C2\u00A0 Gibson\u00C2\u00A0and\u00C2\u00A0Watkinson,\u00C2\u00A01990;\u00C2\u00A0Kidd\u00C2\u00A0Creek,\u00C2\u00A0Hannington\u00C2\u00A0and\u00C2\u00A0Barrie,\u00C2\u00A01999),\u00C2\u00A0Proterozoic\u00C2\u00A0age\u00C2\u00A0(e.g.,\u00C2\u00A0 Flin\u00C2\u00A0Flon,\u00C2\u00A0Syme\u00C2\u00A0and\u00C2\u00A0Bailes,\u00C2\u00A01993)\u00C2\u00A0and\u00C2\u00A0Phanerozoic\u00C2\u00A0age\u00C2\u00A0(e.g.,\u00C2\u00A0Sibai,\u00C2\u00A0Gai;\u00C2\u00A0Herrington\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02005).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Cretaceous\u00C2\u00A0marginal\u00C2\u00A0basins\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0western\u00C2\u00A0margin\u00C2\u00A0of\u00C2\u00A0South\u00C2\u00A0America\u00C2\u00A0have\u00C2\u00A0been\u00C2\u00A0ascribed\u00C2\u00A0 to\u00C2\u00A0various\u00C2\u00A0tectonomagmatic\u00C2\u00A0scenarios\u00C2\u00A0ranging\u00C2\u00A0from\u00C2\u00A0\u00E2\u0080\u0098aborted\u00C2\u00A0ophiolite\u00E2\u0080\u0099\u00C2\u00A0(Aguirre\u00C2\u00A0and\u00C2\u00A0Offler,\u00C2\u00A0 1985),\u00C2\u00A0Gulf\u00C2\u00A0of\u00C2\u00A0California\u00E2\u0080\u0090type\u00C2\u00A0continental\u00C2\u00A0rifts\u00C2\u00A0(Atherton,\u00C2\u00A01990),\u00C2\u00A0modified\u00C2\u00A0back\u00E2\u0080\u0090arc\u00C2\u00A0spreading\u00C2\u00A0 centres,\u00C2\u00A0\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0potential\u00C2\u00A0arc\u00C2\u00A0lying\u00C2\u00A0west\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0present\u00C2\u00A0coast\u00C2\u00A0(Atherton\u00C2\u00A0et\u00C2\u00A0al,\u00C2\u00A01983;\u00C2\u00A0Petford\u00C2\u00A0 and\u00C2\u00A0Atherton,\u00C2\u00A01995),\u00C2\u00A0arc\u00C2\u00A0models\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0a\u00C2\u00A0steeply\u00C2\u00A0dipping\u00C2\u00A0subduction\u00C2\u00A0zone\u00C2\u00A0(Soler\u00C2\u00A0and\u00C2\u00A0 Bonhomme,\u00C2\u00A01990),\u00C2\u00A0and\u00C2\u00A0accreted\u00C2\u00A0island\u00C2\u00A0arc\u00C2\u00A0or\u00C2\u00A0back\u00E2\u0080\u0090arc\u00C2\u00A0(Wise,\u00C2\u00A02000).\u00C2\u00A0\u00C2\u00A0Whereas\u00C2\u00A0the\u00C2\u00A0Western\u00C2\u00A0 Peruvian\u00C2\u00A0Trough\u00C2\u00A0of\u00C2\u00A0central\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0is\u00C2\u00A0partly\u00C2\u00A0eroded\u00C2\u00A0along\u00C2\u00A0its\u00C2\u00A0western\u00C2\u00A0margin,\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0in\u00C2\u00A0 northwestern\u00C2\u00A0region\u00C2\u00A0of\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0and\u00C2\u00A0southwestern\u00C2\u00A0Ecuador\u00C2\u00A0includes\u00C2\u00A0both\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0 forearc\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0west.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0allochthonous\u00C2\u00A0Amotape\u00C2\u00A0complex\u00C2\u00A0(Mourier\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01988;\u00C2\u00A0Noble\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A0 1997)\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0Mesozoic\u00C2\u00A0continental\u00C2\u00A0margin\u00C2\u00A0Olmos\u00C2\u00A0complex\u00C2\u00A0(Reyes\u00C2\u00A0and\u00C2\u00A0Caldas,\u00C2\u00A01987)\u00C2\u00A0are\u00C2\u00A0 preserved\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A0present\u00C2\u00A0day\u00C2\u00A0margin\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0sequences.\u00C2\u00A0\u00C2\u00A0With\u00C2\u00A0all\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 tectonostratigraphic\u00C2\u00A0components\u00C2\u00A0preserved,\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0provides\u00C2\u00A0the\u00C2\u00A0best\u00C2\u00A0opportunity\u00C2\u00A0 to\u00C2\u00A0study\u00C2\u00A0the\u00C2\u00A0tectonic\u00C2\u00A0history\u00C2\u00A0and\u00C2\u00A0magmatism\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Cretaceous\u00C2\u00A0marginal\u00C2\u00A0basins\u00C2\u00A0of\u00C2\u00A0Per\u00C3\u00BA\u00E2\u0080\u0090 Ecuador.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0this\u00C2\u00A0chapter\u00C2\u00A0the\u00C2\u00A0petrogenesis\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0relationship\u00C2\u00A0to\u00C2\u00A0VMS\u00C2\u00A0 formation\u00C2\u00A0is\u00C2\u00A0investigated.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 4.3\u00C2\u00A0 Tectonic\u00C2\u00A0Setting\u00C2\u00A0 The\u00C2\u00A0Tambogrande\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0formed\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0in\u00C2\u00A0association\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0 deposition\u00C2\u00A0of\u00C2\u00A0mid\u00E2\u0080\u0090Cretaceous\u00C2\u00A0volcano\u00E2\u0080\u0090sedimentary\u00C2\u00A0strata\u00C2\u00A0(Reyes\u00C2\u00A0and\u00C2\u00A0Caldas,\u00C2\u00A01987;\u00C2\u00A0Chap.\u00C2\u00A02.).\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0represents\u00C2\u00A0the\u00C2\u00A0northern\u00C2\u00A0portion\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0much\u00C2\u00A0larger\u00C2\u00A0and\u00C2\u00A0segmented\u00C2\u00A0Mesozoic\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 89\u00C2\u00A0 \u00C2\u00A0 continental\u00C2\u00A0margin\u00C2\u00A0rift\u00C2\u00A0basin\u00C2\u00A0extends\u00C2\u00A0from\u00C2\u00A0southwestern\u00C2\u00A0Ecuador\u00C2\u00A0(Jaillard\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01996)\u00C2\u00A0\u00C2\u00A0along\u00C2\u00A0 the\u00C2\u00A0Peruvian\u00C2\u00A0coast\u00C2\u00A0(Western\u00C2\u00A0Peruvian\u00C2\u00A0Trough\u00C2\u00A0or\u00C2\u00A0Huarmey\u00E2\u0080\u0090Ca\u00C3\u00B1ete\u00C2\u00A0Marginal\u00C2\u00A0Trough;\u00C2\u00A0Atherton\u00C2\u00A0et\u00C2\u00A0 al.,\u00C2\u00A01983;\u00C2\u00A0Benavides\u00E2\u0080\u0090C\u00C3\u00A1ceres,\u00C2\u00A01999).\u00C2\u00A0\u00C2\u00A0Similar\u00C2\u00A0arc\u00E2\u0080\u0090related\u00C2\u00A0marginal\u00C2\u00A0rifts\u00C2\u00A0occur\u00C2\u00A0in\u00C2\u00A0Chile\u00C2\u00A0(Coast\u00C2\u00A0 Range;\u00C2\u00A0Vergara\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01995)\u00C2\u00A0and\u00C2\u00A0Argentina\u00C2\u00A0(Rocas\u00C2\u00A0Verdes\u00C2\u00A0basin;\u00C2\u00A0Dalziel,\u00C2\u00A01981;\u00C2\u00A0Hanson\u00C2\u00A0and\u00C2\u00A0 Wilson,\u00C2\u00A01991).\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0marginal\u00C2\u00A0basins\u00C2\u00A0represent\u00C2\u00A0an\u00C2\u00A0episode\u00C2\u00A0of\u00C2\u00A0extension\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0first\u00C2\u00A0phase\u00C2\u00A0 (~Mesozoic)\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Andean\u00C2\u00A0cycle\u00C2\u00A0in\u00C2\u00A0which\u00C2\u00A0Mariana\u00E2\u0080\u0090type\u00C2\u00A0subduction\u00C2\u00A0permitted\u00C2\u00A0crustal\u00C2\u00A0 attenuation,\u00C2\u00A0deposition\u00C2\u00A0of\u00C2\u00A0major\u00C2\u00A0marine\u00C2\u00A0sequences\u00C2\u00A0and\u00C2\u00A0eruption\u00C2\u00A0of\u00C2\u00A0large\u00C2\u00A0volumes\u00C2\u00A0of\u00C2\u00A0mafic\u00E2\u0080\u0090 dominated,\u00C2\u00A0subduction\u00E2\u0080\u0090related\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0(Benavides\u00E2\u0080\u0090C\u00C3\u00A1ceres,\u00C2\u00A01999).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0rift\u00C2\u00A0regime\u00C2\u00A0is\u00C2\u00A0 temporally\u00C2\u00A0linked\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0opening\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0South\u00C2\u00A0Atlantic\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Cretaceous\u00C2\u00A0and\u00C2\u00A0lasted\u00C2\u00A0until\u00C2\u00A0the\u00C2\u00A0 Late\u00C2\u00A0Cretaceous\u00C2\u00A0when\u00C2\u00A0the\u00C2\u00A0geodynamical\u00C2\u00A0cycle\u00C2\u00A0shifted\u00C2\u00A0towards\u00C2\u00A0Andean\u00E2\u0080\u0090type\u00C2\u00A0subduction\u00C2\u00A0in\u00C2\u00A0part\u00C2\u00A0 due\u00C2\u00A0to\u00C2\u00A0active\u00C2\u00A0spreading\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0South\u00C2\u00A0Atlantic\u00C2\u00A0(Soler\u00C2\u00A0and\u00C2\u00A0Bonhomme,\u00C2\u00A01990).\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0resulted\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0 termination\u00C2\u00A0of\u00C2\u00A0marine\u00C2\u00A0sedimentation\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0beginning\u00C2\u00A0of\u00C2\u00A0contractional\u00C2\u00A0tectonism,\u00C2\u00A0continental\u00C2\u00A0 arc\u00C2\u00A0magmatism\u00C2\u00A0and\u00C2\u00A0a\u00C2\u00A0tectonic\u00C2\u00A0regime\u00C2\u00A0which\u00C2\u00A0continues\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0present\u00C2\u00A0day\u00C2\u00A0(Benavides\u00E2\u0080\u0090C\u00C3\u00A1ceres,\u00C2\u00A0 1999;\u00C2\u00A0Jaillard\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02000)\u00C2\u00A0.\u00C2\u00A0 The\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0is\u00C2\u00A0located\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0Huancabamba\u00C2\u00A0deflection,\u00C2\u00A0a\u00C2\u00A0major\u00C2\u00A0oroclinal\u00C2\u00A0bend\u00C2\u00A0in\u00C2\u00A0 the\u00C2\u00A0Andes\u00C2\u00A0which\u00C2\u00A0separates\u00C2\u00A0the\u00C2\u00A0north\u00E2\u0080\u0090northwest\u00E2\u0080\u0090trending\u00C2\u00A0Peruvian\u00C2\u00A0Andes\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0northeast\u00E2\u0080\u0090 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1994),\u00C2\u00A0whereas\u00C2\u00A0a\u00C2\u00A0sinistral\u00C2\u00A0transform\u00C2\u00A0system\u00C2\u00A0occurred\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0Peruvian\u00C2\u00A0segment\u00C2\u00A0(Jaillard\u00C2\u00A0et\u00C2\u00A0 al.,\u00C2\u00A02000).\u00C2\u00A0\u00C2\u00A0During\u00C2\u00A0the\u00C2\u00A0Early\u00C2\u00A0Cretaceous\u00C2\u00A0a\u00C2\u00A0convergence\u00C2\u00A0shift\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0northeast\u00C2\u00A0terminated\u00C2\u00A0the\u00C2\u00A0 Ecuadorian\u00C2\u00A0magmatic\u00C2\u00A0arc\u00C2\u00A0and\u00C2\u00A0established\u00C2\u00A0the\u00C2\u00A0conditions\u00C2\u00A0for\u00C2\u00A0subduction\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0Peruvian\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 90\u00C2\u00A0 \u00C2\u00A0 segment\u00C2\u00A0(Jaillard\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02000).\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0tectonic\u00C2\u00A0development\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0Peruvian\u00E2\u0080\u0090Ecuadorian\u00C2\u00A0 margin\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Early\u00C2\u00A0Cretaceous\u00C2\u00A0is\u00C2\u00A0synchronous\u00C2\u00A0with\u00C2\u00A0a\u00C2\u00A0rift\u00C2\u00A0event\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0formation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 Lancones\u00C2\u00A0basin.\u00C2\u00A0\u00C2\u00A0Several\u00C2\u00A0accretionary\u00C2\u00A0events\u00C2\u00A0beginning\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Early\u00C2\u00A0Cretaceous\u00C2\u00A0also\u00C2\u00A0played\u00C2\u00A0a\u00C2\u00A0 major\u00C2\u00A0role\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0development\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0margin,\u00C2\u00A0especially\u00C2\u00A0in\u00C2\u00A0northwestern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0and\u00C2\u00A0Ecuador\u00C2\u00A0 where\u00C2\u00A0allochthonous\u00C2\u00A0terranes\u00C2\u00A0are\u00C2\u00A0identified\u00C2\u00A0(Litherland\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01994).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0Amotape\u00C2\u00A0terrane\u00C2\u00A0 represents\u00C2\u00A0a\u00C2\u00A0microcontinental\u00C2\u00A0block\u00C2\u00A0comprised\u00C2\u00A0of\u00C2\u00A0metamorphosed\u00C2\u00A0sedimentary\u00C2\u00A0and\u00C2\u00A0plutonic\u00C2\u00A0 rocks\u00C2\u00A0with\u00C2\u00A0Middle\u00C2\u00A0to\u00C2\u00A0Late\u00C2\u00A0Triassic\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0ages\u00C2\u00A0(Noble\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01997;\u00C2\u00A0Appendix\u00C2\u00A0A),\u00C2\u00A0as\u00C2\u00A0well\u00C2\u00A0as\u00C2\u00A0high\u00E2\u0080\u0090 pressure\u00C2\u00A0metamorphosed\u00C2\u00A0oceanic\u00C2\u00A0terranes\u00C2\u00A0thought\u00C2\u00A0to\u00C2\u00A0represent\u00C2\u00A0mid\u00E2\u0080\u0090ocean\u00C2\u00A0ridge\u00C2\u00A0and\u00C2\u00A0oceanic\u00C2\u00A0 plateau\u00C2\u00A0basalt\u00C2\u00A0(e.g.,\u00C2\u00A0Raspas\u00C2\u00A0metamorphic\u00C2\u00A0complex;\u00C2\u00A0Arculus\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01999;\u00C2\u00A0Bosch\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02002).\u00C2\u00A0\u00C2\u00A0 Mourier\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1988)\u00C2\u00A0suggest\u00C2\u00A0the\u00C2\u00A0Amotape\u00C2\u00A0terrane\u00C2\u00A0arrived\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0south,\u00C2\u00A0the\u00C2\u00A0timing\u00C2\u00A0of\u00C2\u00A0which\u00C2\u00A0 is\u00C2\u00A0constrained\u00C2\u00A0by\u00C2\u00A0cooling\u00C2\u00A0ages\u00C2\u00A0of\u00C2\u00A0~132\u00E2\u0080\u0090110\u00C2\u00A0Ma\u00C2\u00A0(Bosch\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02002).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0accretionary\u00C2\u00A0event\u00C2\u00A0 likely\u00C2\u00A0triggered\u00C2\u00A0the\u00C2\u00A0initiation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0new\u00C2\u00A0subduction\u00C2\u00A0zone\u00C2\u00A0outboard\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Amotape\u00C2\u00A0terrane\u00C2\u00A0 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represent\u00C2\u00A0the\u00C2\u00A0Jurassic\u00C2\u00A0to\u00C2\u00A0Early\u00C2\u00A0Cretaceous\u00C2\u00A0pre\u00E2\u0080\u0090rift\u00C2\u00A0Andean\u00C2\u00A0margin\u00C2\u00A0(Benavides\u00E2\u0080\u0090C\u00C3\u00A1ceres,\u00C2\u00A01999).\u00C2\u00A0\u00C2\u00A0 Geophysical\u00C2\u00A0models\u00C2\u00A0constrain\u00C2\u00A0the\u00C2\u00A0crustal\u00C2\u00A0architecture\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0continental\u00C2\u00A0margin\u00C2\u00A0of\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0and\u00C2\u00A0 demonstrate\u00C2\u00A0a\u00C2\u00A0large\u00C2\u00A0arch\u00E2\u0080\u0090like\u00C2\u00A0structure\u00C2\u00A0of\u00C2\u00A0dense\u00C2\u00A0(3.25\u00C2\u00A0g/cm3)\u00C2\u00A0material\u00C2\u00A0that\u00C2\u00A0coincides\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0 Mesozoic\u00C2\u00A0volcanic\u00C2\u00A0rift\u00C2\u00A0sequences,\u00C2\u00A0interpreted\u00C2\u00A0to\u00C2\u00A0be\u00C2\u00A0oceanic\u00C2\u00A0crust\u00C2\u00A0and\u00C2\u00A0separating\u00C2\u00A0continental\u00C2\u00A0 blocks\u00C2\u00A0(Couch\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01981;\u00C2\u00A0Jones,\u00C2\u00A01981).\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0continental\u00C2\u00A0blocks\u00C2\u00A0were\u00C2\u00A0topographic\u00C2\u00A0highs\u00C2\u00A0 during\u00C2\u00A0marine\u00C2\u00A0deposition\u00C2\u00A0in\u00C2\u00A0Mesozoic\u00C2\u00A0times\u00C2\u00A0(Cobbing\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01981).\u00C2\u00A0\u00C2\u00A0To\u00C2\u00A0the\u00C2\u00A0southeast\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 91\u00C2\u00A0 \u00C2\u00A0 Lancones\u00C2\u00A0Basin,\u00C2\u00A0the\u00C2\u00A0Paleozoic(?)\u00C2\u00A0Olmos\u00C2\u00A0Massif\u00C2\u00A0is\u00C2\u00A0a\u00C2\u00A0probable\u00C2\u00A0reactivated\u00C2\u00A0margin\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 Amazonian\u00C2\u00A0craton\u00C2\u00A0(Macfarlane,\u00C2\u00A01999).\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0poorly\u00C2\u00A0characterized\u00C2\u00A0terrane\u00C2\u00A0consists\u00C2\u00A0of\u00C2\u00A0pre\u00E2\u0080\u0090 Ordovician\u00C2\u00A0greenschist\u00C2\u00A0facies\u00C2\u00A0pelitic\u00C2\u00A0to\u00C2\u00A0psammitic\u00C2\u00A0rocks\u00C2\u00A0overlain\u00C2\u00A0by\u00C2\u00A0platform\u00C2\u00A0carbonate\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0 Triassic\u00C2\u00A0to\u00C2\u00A0Early\u00C2\u00A0Jurassic\u00C2\u00A0age.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0Olmos\u00C2\u00A0complex\u00C2\u00A0is\u00C2\u00A0considered\u00C2\u00A0equivalent\u00C2\u00A0to\u00C2\u00A0Mara\u00C3\u00B1on\u00C2\u00A0 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the\u00C2\u00A0trend.\u00C2\u00A0\u00C2\u00A0Tertiary\u00C2\u00A0cover\u00C2\u00A0blankets\u00C2\u00A0the\u00C2\u00A0basin\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0southwest\u00C2\u00A0for\u00C2\u00A0an\u00C2\u00A0additional\u00C2\u00A050\u00C2\u00A0kilometres.\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0basin\u00C2\u00A0can\u00C2\u00A0be\u00C2\u00A0subdivided\u00C2\u00A0in\u00C2\u00A0an\u00C2\u00A0eastern\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0and\u00C2\u00A0western\u00C2\u00A0sedimentary\u00C2\u00A0forearc.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0 volcanic\u00C2\u00A0arc\u00C2\u00A0sequence,\u00C2\u00A0up\u00C2\u00A0to\u00C2\u00A080\u00C2\u00A0km\u00C2\u00A0wide,\u00C2\u00A0is\u00C2\u00A0dominated\u00C2\u00A0by\u00C2\u00A0submarine\u00C2\u00A0mafic\u00C2\u00A0volcanic\u00C2\u00A0and\u00C2\u00A0 volcaniclastic\u00C2\u00A0rocks,\u00C2\u00A0and\u00C2\u00A0grades\u00C2\u00A0into\u00C2\u00A0forearc\u00C2\u00A0sedimentary\u00C2\u00A0rocks\u00C2\u00A0which\u00C2\u00A0dominate\u00C2\u00A0the\u00C2\u00A0western\u00C2\u00A0 portion\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0(Jaillard\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01999).\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0~3\u00C2\u00A0km\u00C2\u00A0thick\u00C2\u00A0turbidite\u00C2\u00A0sequence,\u00C2\u00A0the\u00C2\u00A0Copa\u00C2\u00A0 Sombrero\u00C2\u00A0Group\u00C2\u00A0(Ch\u00C3\u00A1vez\u00C2\u00A0and\u00C2\u00A0Nu\u00C3\u00B1ez\u00C2\u00A0del\u00C2\u00A0Prado,\u00C2\u00A01991;\u00C2\u00A0Morris\u00C2\u00A0and\u00C2\u00A0Aleman,\u00C2\u00A01975;\u00C2\u00A0Jaillard\u00C2\u00A0et\u00C2\u00A0al,\u00C2\u00A0 1996,\u00C2\u00A01999),\u00C2\u00A0represents\u00C2\u00A0the\u00C2\u00A0forearc\u00C2\u00A0and\u00C2\u00A0temporally\u00C2\u00A0overlaps\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0sequence.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0four\u00C2\u00A0formations\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0sequence\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0have\u00C2\u00A0a\u00C2\u00A0cumulative\u00C2\u00A0 thickness\u00C2\u00A0of\u00C2\u00A0~\u00C2\u00A08\u00C2\u00A0to\u00C2\u00A010\u00C2\u00A0km\u00C2\u00A0and\u00C2\u00A0are\u00C2\u00A0subdivided\u00C2\u00A0into\u00C2\u00A0two\u00C2\u00A0main\u00C2\u00A0tectono\u00E2\u0080\u0090volcanic\u00C2\u00A0phases\u00C2\u00A0based\u00C2\u00A0on\u00C2\u00A0 depositional\u00C2\u00A0facies,\u00C2\u00A0composition\u00C2\u00A0and\u00C2\u00A0chronology\u00C2\u00A0(Figs.\u00C2\u00A04.4,\u00C2\u00A04.5;\u00C2\u00A0Chap.\u00C2\u00A02).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 Formation\u00C2\u00A0represents\u00C2\u00A0phase\u00C2\u00A01\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0El\u00C2\u00A0Ereo,\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0and\u00C2\u00A0Lancones\u00C2\u00A0formations\u00C2\u00A0record\u00C2\u00A0 phase\u00C2\u00A02.\u00C2\u00A0\u00C2\u00A0Phase\u00C2\u00A01\u00C2\u00A0is\u00C2\u00A0a\u00C2\u00A0mafic\u00E2\u0080\u0090dominated\u00C2\u00A0sequence\u00C2\u00A0characterized\u00C2\u00A0by\u00C2\u00A0lava\u00C2\u00A0flows\u00C2\u00A0and\u00C2\u00A0associated\u00C2\u00A0 breccias,\u00C2\u00A0minor\u00C2\u00A0aphyric\u00C2\u00A0felsic\u00C2\u00A0lavas,\u00C2\u00A0and\u00C2\u00A0a\u00C2\u00A0general\u00C2\u00A0absence\u00C2\u00A0of\u00C2\u00A0siliciclastic\u00C2\u00A0sedimentary\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 92\u00C2\u00A0 \u00C2\u00A0 rocks\u00C2\u00A0are\u00C2\u00A0interpreted\u00C2\u00A0to\u00C2\u00A0have\u00C2\u00A0been\u00C2\u00A0deposited\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0relatively\u00C2\u00A0deep\u00C2\u00A0water\u00C2\u00A0environment.\u00C2\u00A0\u00C2\u00A0All\u00C2\u00A0VMS\u00C2\u00A0 deposits\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0are\u00C2\u00A0hosted\u00C2\u00A0by\u00C2\u00A0the\u00C2\u00A0phase\u00C2\u00A01\u00C2\u00A0volcanic\u00C2\u00A0sequence.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0phase\u00C2\u00A02\u00C2\u00A0volcanic\u00C2\u00A0cycle\u00C2\u00A0is\u00C2\u00A0an\u00C2\u00A08\u00C2\u00A0km\u00E2\u0080\u0090thick\u00C2\u00A0sequence\u00C2\u00A0of\u00C2\u00A0mafic\u00C2\u00A0to\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0and\u00C2\u00A0 volcaniclastic\u00C2\u00A0rocks\u00C2\u00A0with\u00C2\u00A0subordinate\u00C2\u00A0calcareous\u00C2\u00A0and\u00C2\u00A0siliciclastic\u00C2\u00A0sedimentary\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0rocks\u00C2\u00A0 represent\u00C2\u00A0in\u00C2\u00A0general\u00C2\u00A0a\u00C2\u00A0relatively\u00C2\u00A0more\u00C2\u00A0shallow\u00C2\u00A0water\u00C2\u00A0setting.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0upper\u00C2\u00A0part\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0sequence\u00C2\u00A0 includes\u00C2\u00A0re\u00E2\u0080\u0090worked\u00C2\u00A0volcaniclastic\u00C2\u00A0rocks\u00C2\u00A0which\u00C2\u00A0grade\u00C2\u00A0into\u00C2\u00A0sedimentary\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0upper\u00C2\u00A0sectors\u00C2\u00A0 marking\u00C2\u00A0a\u00C2\u00A0transition\u00C2\u00A0to\u00C2\u00A0forearc\u00C2\u00A0turbidites\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Copa\u00C2\u00A0Sombrero\u00C2\u00A0Group.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0Ecuador\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0 arc\u00C2\u00A0sequence\u00C2\u00A0has\u00C2\u00A0not\u00C2\u00A0been\u00C2\u00A0studied\u00C2\u00A0in\u00C2\u00A0detail\u00C2\u00A0and\u00C2\u00A0is\u00C2\u00A0described\u00C2\u00A0as\u00C2\u00A0a\u00C2\u00A02\u00C2\u00A0to\u00C2\u00A03\u00C2\u00A0km\u00E2\u0080\u0090thick\u00C2\u00A0package\u00C2\u00A0of\u00C2\u00A0 dominantly\u00C2\u00A0mafic\u00C2\u00A0pillow\u00C2\u00A0lavas\u00C2\u00A0and\u00C2\u00A0related\u00C2\u00A0volcaniclastic\u00C2\u00A0rocks\u00C2\u00A0(Jaillard\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01996).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0Metamorphic\u00C2\u00A0grades\u00C2\u00A0range\u00C2\u00A0from\u00C2\u00A0zeolite\u00C2\u00A0to\u00C2\u00A0lower\u00C2\u00A0greenschist\u00C2\u00A0assemblages,\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0higher\u00C2\u00A0 metamorphic\u00C2\u00A0grades\u00C2\u00A0occurring\u00C2\u00A0near\u00C2\u00A0plutonic\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0Diagenesis\u00C2\u00A0and\u00C2\u00A0low\u00E2\u0080\u0090temperature,\u00C2\u00A0near\u00C2\u00A0 seafloor\u00C2\u00A0metasomatism,\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0ambient\u00C2\u00A0seawater\u00E2\u0080\u0090rock\u00C2\u00A0interaction\u00C2\u00A0(halmyrolosis),\u00C2\u00A0have\u00C2\u00A0resulted\u00C2\u00A0 in\u00C2\u00A0a\u00C2\u00A0wide\u00C2\u00A0range\u00C2\u00A0of\u00C2\u00A0low\u00E2\u0080\u0090temperature\u00C2\u00A0replacement\u00C2\u00A0and\u00C2\u00A0open\u00E2\u0080\u0090space\u00E2\u0080\u0090filling\u00C2\u00A0minerals\u00C2\u00A0within\u00C2\u00A0basaltic\u00C2\u00A0 rocks,\u00C2\u00A0including\u00C2\u00A0analcite,\u00C2\u00A0albite\u00C2\u00A0(after\u00C2\u00A0plagioclase),\u00C2\u00A0amphibole\u00C2\u00A0(uralitized\u00C2\u00A0clinopyroxene),\u00C2\u00A0 carbonate\u00C2\u00A0minerals,\u00C2\u00A0chlorite,\u00C2\u00A0epidote,\u00C2\u00A0hematite,\u00C2\u00A0palagonite\u00C2\u00A0(after\u00C2\u00A0groundmass\u00C2\u00A0glass),\u00C2\u00A0prehnite,\u00C2\u00A0 pumpellyite,\u00C2\u00A0sericite\u00C2\u00A0and/or\u00C2\u00A0various\u00C2\u00A0clays\u00C2\u00A0(sausseritized\u00C2\u00A0feldspar),\u00C2\u00A0and\u00C2\u00A0zeolites.\u00C2\u00A0\u00C2\u00A0Hydrothermal\u00C2\u00A0 alteration\u00C2\u00A0is\u00C2\u00A0confined\u00C2\u00A0to\u00C2\u00A0discordant\u00C2\u00A0zones\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0footwall\u00C2\u00A0rocks\u00C2\u00A0immediately\u00C2\u00A0below\u00C2\u00A0massive\u00C2\u00A0 sulphide\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0includes\u00C2\u00A0variable\u00C2\u00A0replacement\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0rocks\u00C2\u00A0by\u00C2\u00A0chlorite,\u00C2\u00A0sericite\u00C2\u00A0and\u00C2\u00A0quartz\u00C2\u00A0 in\u00C2\u00A0addition\u00C2\u00A0to\u00C2\u00A0stringer\u00C2\u00A0and\u00C2\u00A0disseminated\u00C2\u00A0sulphide\u00C2\u00A0mineralization\u00C2\u00A0(Tegart\u00C2\u00A0et\u00C2\u00A0al,\u00C2\u00A02000).\u00C2\u00A0\u00C2\u00A0None\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0this\u00C2\u00A0study\u00C2\u00A0show\u00C2\u00A0the\u00C2\u00A0effects\u00C2\u00A0of\u00C2\u00A0dynamic\u00C2\u00A0metamorphism\u00C2\u00A0and\u00C2\u00A0primary\u00C2\u00A0textures\u00C2\u00A0are\u00C2\u00A0 generally\u00C2\u00A0well\u00C2\u00A0preserved.\u00C2\u00A0 4.4.1\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0 The\u00C2\u00A0lowermost\u00C2\u00A0volcanic\u00C2\u00A0sequence,\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation,\u00C2\u00A0is\u00C2\u00A0characterized\u00C2\u00A0by\u00C2\u00A0 bimodal\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0and\u00C2\u00A0is\u00C2\u00A0dominated\u00C2\u00A0by\u00C2\u00A0basalt.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0depositional\u00C2\u00A0environment\u00C2\u00A0is\u00C2\u00A0inferred\u00C2\u00A0to\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 93\u00C2\u00A0 \u00C2\u00A0 have\u00C2\u00A0been\u00C2\u00A0a\u00C2\u00A0relatively\u00C2\u00A0deep\u00C2\u00A0marine\u00C2\u00A0based\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0absence\u00C2\u00A0of\u00C2\u00A0pyroclastic\u00C2\u00A0rocks\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0presence\u00C2\u00A0 of\u00C2\u00A0minor\u00C2\u00A0black\u00C2\u00A0mudstone\u00C2\u00A0as\u00C2\u00A0the\u00C2\u00A0sedimentary\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0Felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0represent\u00C2\u00A0a\u00C2\u00A0minor\u00C2\u00A0 component\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0total\u00C2\u00A0estimated\u00C2\u00A02,500\u00C2\u00A0metre\u00C2\u00A0thickness\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0formation.\u00C2\u00A0\u00C2\u00A0Volcanic\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0host\u00C2\u00A0all\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0prospects\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Tambogrande\u00C2\u00A0 district\u00C2\u00A0(TG1,\u00C2\u00A0TG3,\u00C2\u00A0and\u00C2\u00A0B5).\u00C2\u00A0\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0zircon\u00C2\u00A0ages\u00C2\u00A0of\u00C2\u00A099.8\u00C2\u00A0to\u00C2\u00A0104.8\u00C2\u00A0Ma\u00C2\u00A0for\u00C2\u00A0syn\u00E2\u0080\u0090mineralization\u00C2\u00A0rhyolitic\u00C2\u00A0 volcaniclastic\u00C2\u00A0rocks\u00C2\u00A0and\u00C2\u00A0post\u00E2\u0080\u0090mineralization\u00C2\u00A0rhyolite\u00C2\u00A0dykes,\u00C2\u00A0respectively,\u00C2\u00A0have\u00C2\u00A0been\u00C2\u00A0determined\u00C2\u00A0 (Chap.\u00C2\u00A02).\u00C2\u00A0 Basalt\u00C2\u00A0in\u00C2\u00A0this\u00C2\u00A0formation\u00C2\u00A0is\u00C2\u00A0typically\u00C2\u00A0feldspar\u00E2\u0080\u0090augite\u00C2\u00A0porphyritic,\u00C2\u00A0amygdaloidal\u00C2\u00A0and\u00C2\u00A0occurred\u00C2\u00A0 as\u00C2\u00A0massive\u00C2\u00A0to\u00C2\u00A0pillowed\u00C2\u00A0flows\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0a\u00C2\u00A0variety\u00C2\u00A0of\u00C2\u00A0autoclastic\u00C2\u00A0breccias,\u00C2\u00A0ranging\u00C2\u00A0from\u00C2\u00A0 pillow\u00C2\u00A0fragment\u00C2\u00A0and\u00C2\u00A0talus\u00C2\u00A0breccia,\u00C2\u00A0hyaloclastite\u00C2\u00A0breccias\u00C2\u00A0and\u00C2\u00A0globular\u00C2\u00A0autobreccia.\u00C2\u00A0\u00C2\u00A0Felsic\u00C2\u00A0 volcanic\u00C2\u00A0rocks\u00C2\u00A0are\u00C2\u00A0represented\u00C2\u00A0by\u00C2\u00A0massive\u00C2\u00A0to\u00C2\u00A0flow\u00E2\u0080\u0090banded\u00C2\u00A0lavas,\u00C2\u00A0domes\u00C2\u00A0or\u00C2\u00A0dykes\u00C2\u00A0of\u00C2\u00A0dacitic\u00C2\u00A0to\u00C2\u00A0 rhyolitic\u00C2\u00A0composition\u00C2\u00A0and\u00C2\u00A0are\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0autoclastic\u00C2\u00A0proximal\u00C2\u00A0volcaniclastic\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0 rhyolite\u00C2\u00A0flow\u00E2\u0080\u0090dome\u00C2\u00A0complex,\u00C2\u00A0up\u00C2\u00A0to\u00C2\u00A02\u00C2\u00A0km\u00C2\u00A0in\u00C2\u00A0extent\u00C2\u00A0by\u00C2\u00A0250\u00C2\u00A0m\u00C2\u00A0in\u00C2\u00A0composite\u00C2\u00A0thickness,\u00C2\u00A0is\u00C2\u00A0 dominated\u00C2\u00A0by\u00C2\u00A0buff\u00C2\u00A0to\u00C2\u00A0light\u00C2\u00A0grey,\u00C2\u00A0aphyric\u00C2\u00A0to\u00C2\u00A0weakly\u00C2\u00A0feldspar\u00C2\u00A0porphyritic,\u00C2\u00A0locally\u00C2\u00A0spherulitic\u00C2\u00A0and\u00C2\u00A0 commonly\u00C2\u00A0perlitic\u00C2\u00A0rhyolite.\u00C2\u00A0\u00C2\u00A0Plagioclase\u00C2\u00A0and\u00C2\u00A0resorbed\u00C2\u00A0quartz\u00C2\u00A0porphyritic\u00C2\u00A0rhyolite\u00C2\u00A0dykes\u00C2\u00A0cut\u00C2\u00A0 massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0(e.g.,\u00C2\u00A0TG1).\u00C2\u00A0\u00C2\u00A0Quartz\u00C2\u00A0porphyritic\u00C2\u00A0rhyolite\u00C2\u00A0lavas,\u00C2\u00A0however,\u00C2\u00A0are\u00C2\u00A0not\u00C2\u00A0 recognized\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation.\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0few\u00C2\u00A0amygdule\u00E2\u0080\u0090rich\u00C2\u00A0dacitic\u00C2\u00A0lava\u00C2\u00A0flows\u00C2\u00A0and\u00C2\u00A0 breccia\u00C2\u00A0deposits\u00C2\u00A0are\u00C2\u00A0conspicuous\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0immediate\u00C2\u00A0hanging\u00C2\u00A0wall\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0TG1\u00C2\u00A0and\u00C2\u00A0TG3\u00C2\u00A0deposits.\u00C2\u00A0\u00C2\u00A0 Volumetrically\u00C2\u00A0minor\u00C2\u00A0pelagic\u00C2\u00A0sedimentary\u00C2\u00A0rocks\u00C2\u00A0are\u00C2\u00A0ubiquitous\u00C2\u00A0throughout\u00C2\u00A0this\u00C2\u00A0formation.\u00C2\u00A0\u00C2\u00A0 4.4.2\u00C2\u00A0 Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation\u00C2\u00A0 \u00C2\u00A0 The\u00C2\u00A0Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation\u00C2\u00A0is\u00C2\u00A0an\u00C2\u00A0entirely\u00C2\u00A0mafic\u00C2\u00A0volcanic\u00C2\u00A0sequence\u00C2\u00A0of\u00C2\u00A0distinct\u00C2\u00A0coarse\u00C2\u00A0 feldspar\u00C2\u00A0porphyritic\u00C2\u00A0lava\u00C2\u00A0and\u00C2\u00A0minor\u00C2\u00A0breccia.\u00C2\u00A0\u00C2\u00A0Lavas\u00C2\u00A0are\u00C2\u00A0generally\u00C2\u00A0massive\u00C2\u00A0with\u00C2\u00A0few\u00C2\u00A0amygdales.\u00C2\u00A0\u00C2\u00A0 Volcaniclastic\u00C2\u00A0rocks\u00C2\u00A0are\u00C2\u00A0typically\u00C2\u00A0thick\u00E2\u0080\u0090bedded,\u00C2\u00A0non\u00E2\u0080\u0090stratified,\u00C2\u00A0boulder\u00E2\u0080\u0090sized\u00C2\u00A0breccia,\u00C2\u00A0though\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 94\u00C2\u00A0 \u00C2\u00A0 fairly\u00C2\u00A0well\u00C2\u00A0sorted\u00C2\u00A0lithic\u00C2\u00A0and\u00C2\u00A0feldspar\u00C2\u00A0crystal\u00C2\u00A0tuff\u00C2\u00A0of\u00C2\u00A0mafic\u00C2\u00A0composition\u00C2\u00A0are\u00C2\u00A0present\u00C2\u00A0near\u00C2\u00A0the\u00C2\u00A0upper\u00C2\u00A0 contact\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 4.4.3\u00C2\u00A0 La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0 The\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0is\u00C2\u00A0a\u00C2\u00A0bimodal\u00C2\u00A0basalt/basaltic\u00E2\u0080\u0090andesite\u00C2\u00A0and\u00C2\u00A0rhyolitic\u00C2\u00A0succession\u00C2\u00A0that\u00C2\u00A0 is\u00C2\u00A0notably\u00C2\u00A0volcaniclastic\u00E2\u0080\u0090rich.\u00C2\u00A0\u00C2\u00A0Mafic\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0formation\u00C2\u00A0include\u00C2\u00A0highly\u00C2\u00A0vesicular,\u00C2\u00A0thick\u00C2\u00A0flows\u00C2\u00A0 and\u00C2\u00A0dykes\u00C2\u00A0with\u00C2\u00A0well\u00C2\u00A0developed\u00C2\u00A0flow\u00C2\u00A0foliations\u00C2\u00A0grading\u00C2\u00A0into\u00C2\u00A0autoclastic\u00C2\u00A0deposits.\u00C2\u00A0\u00C2\u00A0Felsic\u00C2\u00A0rocks\u00C2\u00A0 range\u00C2\u00A0from\u00C2\u00A0quartz\u00E2\u0080\u0090\u00C2\u00A0and/or\u00C2\u00A0feldspar\u00E2\u0080\u0090porphyritic\u00C2\u00A0flows\u00C2\u00A0to\u00C2\u00A0crystal,\u00C2\u00A0lithic,\u00C2\u00A0and\u00C2\u00A0pumice\u00C2\u00A0tuffs.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0 pyroclastic\u00C2\u00A0rocks\u00C2\u00A0include\u00C2\u00A0cross\u00C2\u00A0bedded\u00C2\u00A0volcanic\u00C2\u00A0sandstones\u00C2\u00A0which\u00C2\u00A0indicate\u00C2\u00A0a\u00C2\u00A0relatively\u00C2\u00A0shallow\u00C2\u00A0 water\u00C2\u00A0depositional\u00C2\u00A0setting.\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0zircon\u00C2\u00A0ages\u00C2\u00A0range\u00C2\u00A0from\u00C2\u00A099.3\u00E2\u0080\u009091.1\u00C2\u00A0Ma\u00C2\u00A0(Chap.\u00C2\u00A02).\u00C2\u00A0 4.4.4\u00C2\u00A0 Lancones\u00C2\u00A0Formation\u00C2\u00A0 \u00C2\u00A0 The\u00C2\u00A0Lancones\u00C2\u00A0Formation\u00C2\u00A0consists\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0polylithic,\u00C2\u00A0mafic\u00E2\u0080\u0090dominated,\u00C2\u00A0volcaniclastic\u00C2\u00A0units\u00C2\u00A0 deposited\u00C2\u00A0within\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0relatively\u00C2\u00A0shallow\u00C2\u00A0marine\u00C2\u00A0environment.\u00C2\u00A0\u00C2\u00A0Thick\u00E2\u0080\u0090bedded\u00C2\u00A0and\u00C2\u00A0variably\u00C2\u00A0 stratified\u00C2\u00A0breccias\u00C2\u00A0grade\u00C2\u00A0upwards\u00C2\u00A0into\u00C2\u00A0siliciclastic\u00C2\u00A0and\u00C2\u00A0calcareous\u00C2\u00A0sedimentary\u00C2\u00A0units\u00C2\u00A0(Chapter\u00C2\u00A02).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Fossils\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0age\u00C2\u00A0range\u00C2\u00A0of\u00C2\u00A0late\u00C2\u00A0Albian\u00C2\u00A0and\u00C2\u00A0Early\u00C2\u00A0Cenomanian\u00C2\u00A0are\u00C2\u00A0reported\u00C2\u00A0in\u00C2\u00A0this\u00C2\u00A0formation\u00C2\u00A0 (Reyes\u00C2\u00A0and\u00C2\u00A0Caldas,\u00C2\u00A01987).\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0rocks\u00C2\u00A0mark\u00C2\u00A0the\u00C2\u00A0transition\u00C2\u00A0to\u00C2\u00A0forearc\u00C2\u00A0sedimentary\u00C2\u00A0sequences\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0Copa\u00C2\u00A0Sombrero\u00C2\u00A0Group\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0western\u00C2\u00A0Lancones\u00C2\u00A0Basin,\u00C2\u00A0though\u00C2\u00A0the\u00C2\u00A0contact\u00C2\u00A0is\u00C2\u00A0defined\u00C2\u00A0to\u00C2\u00A0lie\u00C2\u00A0 west\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0study\u00C2\u00A0area\u00C2\u00A0(Jaillard\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01999).\u00C2\u00A0 4.5\u00C2\u00A0 Lithogeochemistry\u00C2\u00A0 4.5.1\u00C2\u00A0 Sampling\u00C2\u00A0Procedures\u00C2\u00A0and\u00C2\u00A0Analytical\u00C2\u00A0Methods\u00C2\u00A0 One\u00C2\u00A0hundred\u00C2\u00A0and\u00C2\u00A0twenty\u00E2\u0080\u0090nine\u00C2\u00A0whole\u00C2\u00A0rock\u00C2\u00A0samples\u00C2\u00A0were\u00C2\u00A0collected\u00C2\u00A0from\u00C2\u00A0volcanic\u00C2\u00A0and\u00C2\u00A0sub\u00E2\u0080\u0090 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John\u00E2\u0080\u0099s,\u00C2\u00A0Newfoundland,\u00C2\u00A0Canada.\u00C2\u00A0\u00C2\u00A0Samples\u00C2\u00A0collected\u00C2\u00A0during\u00C2\u00A02002\u00C2\u00A0regional\u00C2\u00A0mapping\u00C2\u00A0program\u00C2\u00A0from\u00C2\u00A0 outcrop\u00C2\u00A0and\u00C2\u00A0drill\u00C2\u00A0core\u00C2\u00A0were\u00C2\u00A0analyzed\u00C2\u00A0for\u00C2\u00A0major\u00C2\u00A0and\u00C2\u00A0trace\u00C2\u00A0elements\u00C2\u00A0by\u00C2\u00A0a\u00C2\u00A0combination\u00C2\u00A0of\u00C2\u00A0lithium\u00C2\u00A0 metaborate\u00C2\u00A0fusion\u00C2\u00A0ICP\u00E2\u0080\u0090AES\u00C2\u00A0and\u00C2\u00A0ICP\u00E2\u0080\u0090MS\u00C2\u00A0and\u00C2\u00A0pressed\u00C2\u00A0powder\u00C2\u00A0pellet\u00C2\u00A0XRF\u00C2\u00A0at\u00C2\u00A0ALS\u00E2\u0080\u0090Chemex\u00C2\u00A0 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of\u00C2\u00A0nearly\u00C2\u00A0all\u00C2\u00A0submarine\u00C2\u00A0volcanic\u00C2\u00A0rocks,\u00C2\u00A0either\u00C2\u00A0as\u00C2\u00A0a\u00C2\u00A0result\u00C2\u00A0of\u00C2\u00A0halmyrolysis\u00C2\u00A0or\u00C2\u00A0burial\u00C2\u00A0diagenesis.\u00C2\u00A0\u00C2\u00A0 Variable\u00C2\u00A0mobility\u00C2\u00A0of\u00C2\u00A0many\u00C2\u00A0major\u00C2\u00A0elements,\u00C2\u00A0principally\u00C2\u00A0Ca,\u00C2\u00A0K,\u00C2\u00A0Na,\u00C2\u00A0Si,\u00C2\u00A0Mg,\u00C2\u00A0and\u00C2\u00A0Fe\u00C2\u00A0is\u00C2\u00A0noted,\u00C2\u00A0 whereas\u00C2\u00A0Al,\u00C2\u00A0Ti,\u00C2\u00A0and\u00C2\u00A0P\u00C2\u00A0are\u00C2\u00A0generally\u00C2\u00A0immobile\u00C2\u00A0in\u00C2\u00A0VMS\u00E2\u0080\u0090related\u00C2\u00A0altered\u00C2\u00A0rocks\u00C2\u00A0(Hajash\u00C2\u00A0and\u00C2\u00A0Chandler,\u00C2\u00A0 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(e.g.,\u00C2\u00A0titanite,\u00C2\u00A0zircon,\u00C2\u00A0monazite,\u00C2\u00A0xenotime).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0rare\u00C2\u00A0earth\u00C2\u00A0element\u00C2\u00A0(REE)\u00C2\u00A0group\u00C2\u00A0is\u00C2\u00A0generally\u00C2\u00A0 immobile\u00C2\u00A0in\u00C2\u00A0relatively\u00C2\u00A0weakly\u00C2\u00A0altered\u00C2\u00A0(e.g.,\u00C2\u00A0sericitized)\u00C2\u00A0rocks\u00C2\u00A0but\u00C2\u00A0can\u00C2\u00A0be\u00C2\u00A0mobilized\u00C2\u00A0under\u00C2\u00A0 conditions\u00C2\u00A0yielding\u00C2\u00A0chlorite\u00E2\u0080\u0090rich\u00C2\u00A0alteration\u00C2\u00A0assemblages\u00C2\u00A0(Campbell\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01984).\u00C2\u00A0\u00C2\u00A0Divalent\u00C2\u00A0Eu\u00C2\u00A0is\u00C2\u00A0 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range\u00C2\u00A0(YbN\u00C2\u00A0=\u00C2\u00A04\u00E2\u0080\u009013).\u00C2\u00A0\u00C2\u00A0Light\u00C2\u00A0REE\u00C2\u00A0(LREE)\u00C2\u00A0fractionation\u00C2\u00A0is\u00C2\u00A0evident\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0dominantly\u00C2\u00A0negative\u00C2\u00A0slope\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0normalized\u00C2\u00A0REE\u00C2\u00A0profiles\u00C2\u00A0(Fig\u00C2\u00A04.9A)\u00C2\u00A0and\u00C2\u00A0is\u00C2\u00A0emphasized\u00C2\u00A0by\u00C2\u00A0dominantly\u00C2\u00A0positive\u00C2\u00A0(La/Yb)N 4 \u00C2\u00A0 values\u00C2\u00A0of\u00C2\u00A00.6\u00C2\u00A0to\u00C2\u00A07.3\u00C2\u00A0and\u00C2\u00A0mimicked\u00C2\u00A0by\u00C2\u00A0Zr/Y\u00C2\u00A0values\u00C2\u00A0(1.5\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A05.3).\u00C2\u00A0\u00C2\u00A0Slightly\u00C2\u00A0more\u00C2\u00A0evolved\u00C2\u00A0rocks,\u00C2\u00A0i.e.,\u00C2\u00A0 basaltic\u00E2\u0080\u0090andesite,\u00C2\u00A0have\u00C2\u00A0similar\u00C2\u00A0normalized\u00C2\u00A0trace\u00C2\u00A0element\u00C2\u00A0profiles\u00C2\u00A0similar\u00C2\u00A0to\u00C2\u00A0basalt\u00C2\u00A0but\u00C2\u00A0display\u00C2\u00A0 negative\u00C2\u00A0Ti,\u00C2\u00A0Al,\u00C2\u00A0Sc,\u00C2\u00A0and\u00C2\u00A0V\u00C2\u00A0depletion\u00C2\u00A0and\u00C2\u00A0Zr\u00C2\u00A0and\u00C2\u00A0Hf\u00C2\u00A0enrichment,\u00C2\u00A0as\u00C2\u00A0well\u00C2\u00A0as\u00C2\u00A0strong\u00C2\u00A0LREE\u00C2\u00A0 fractionation\u00C2\u00A0(Fig\u00C2\u00A04.9B).\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0pronounced\u00C2\u00A0negative\u00C2\u00A0Nb\u00C2\u00A0anomaly\u00C2\u00A0characterizes\u00C2\u00A0all\u00C2\u00A0normalized\u00C2\u00A0trace\u00C2\u00A0 element\u00C2\u00A0profiles.\u00C2\u00A0\u00C2\u00A0Basalt\u00C2\u00A0in\u00C2\u00A0this\u00C2\u00A0formation\u00C2\u00A0has\u00C2\u00A0HFSE\u00C2\u00A0and\u00C2\u00A0LFSE\u00C2\u00A0abundances\u00C2\u00A0characterized\u00C2\u00A0by\u00C2\u00A0low\u00C2\u00A0 Nb\u00C2\u00A0(Nb/Nb*\u00C2\u00A0=\u00C2\u00A00.06\u00E2\u0080\u00900.5),\u00C2\u00A0low\u00C2\u00A0Ti\u00C2\u00A0(Ti/Ti*\u00C2\u00A0=\u00C2\u00A00.5\u00E2\u0080\u00901.1),\u00C2\u00A0moderate\u00C2\u00A0Zr\u00C2\u00A0(Zr/Zr*\u00C2\u00A0=\u00C2\u00A00.6\u00E2\u0080\u00901.3),\u00C2\u00A0and\u00C2\u00A0relatively\u00C2\u00A0 high\u00C2\u00A0Th\u00C2\u00A0[(Th/La)PM 5 \u00C2\u00A0=\u00C2\u00A01\u00E2\u0080\u00904].\u00C2\u00A0\u00C2\u00A0(La/Yb)N\u00C2\u00A0and\u00C2\u00A0Zr/Y\u00C2\u00A0values\u00C2\u00A0of\u00C2\u00A0basalt\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 Formation\u00C2\u00A0are\u00C2\u00A0distinctively\u00C2\u00A0higher\u00C2\u00A0than\u00C2\u00A0either\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0or\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0formations\u00C2\u00A0(Fig.\u00C2\u00A0 4.10A,\u00C2\u00A0B).\u00C2\u00A0 Low\u00C2\u00A0HFSE\u00C2\u00A0contents\u00C2\u00A0for\u00C2\u00A0felsic\u00C2\u00A0rocks\u00C2\u00A0are\u00C2\u00A0reflected\u00C2\u00A0in\u00C2\u00A0Zr\u00C2\u00A0versus\u00C2\u00A0Ga/Al\u00C2\u00A0and\u00C2\u00A0Nb\u00C2\u00A0versus\u00C2\u00A0Y\u00C2\u00A0plots\u00C2\u00A0(Fig.\u00C2\u00A0 4.11\u00C2\u00A0A\u00E2\u0080\u0090B).\u00C2\u00A0\u00C2\u00A0On\u00C2\u00A0these\u00C2\u00A0discrimination\u00C2\u00A0plots,\u00C2\u00A0felsic\u00C2\u00A0rocks\u00C2\u00A0are\u00C2\u00A0categorized\u00C2\u00A0dominantly\u00C2\u00A0as\u00C2\u00A0M\u00E2\u0080\u0090type\u00C2\u00A0 whereas\u00C2\u00A0some\u00C2\u00A0samples\u00C2\u00A0plot\u00C2\u00A0closer\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0I\u00E2\u0080\u0090type\u00C2\u00A0field\u00C2\u00A0(M\u00E2\u0080\u0090type\u00C2\u00A0or\u00C2\u00A0direct\u00C2\u00A0mantle\u00E2\u0080\u0090type\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0 rocks\u00C2\u00A0are\u00C2\u00A0generally\u00C2\u00A0considered\u00C2\u00A0to\u00C2\u00A0be\u00C2\u00A0derived\u00C2\u00A0from\u00C2\u00A0a\u00C2\u00A0mafic\u00C2\u00A0parent\u00C2\u00A0rock\u00C2\u00A0whereas\u00C2\u00A0I\u00E2\u0080\u0090type\u00C2\u00A0are\u00C2\u00A0 interpreted\u00C2\u00A0to\u00C2\u00A0be\u00C2\u00A0recycled\u00C2\u00A0mantle\u00C2\u00A0material\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0partial\u00C2\u00A0melting\u00C2\u00A0of\u00C2\u00A0juvenile\u00C2\u00A0crust;\u00C2\u00A0Pitcher,\u00C2\u00A0 1983;\u00C2\u00A0Whalen,\u00C2\u00A01985).\u00C2\u00A0\u00C2\u00A0Primitive\u00C2\u00A0mantle\u00E2\u0080\u0090normalized\u00C2\u00A0extended\u00C2\u00A0trace\u00C2\u00A0element\u00C2\u00A0plots\u00C2\u00A0(Fig.\u00C2\u00A04.12A)\u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 4 N denotes chondrite-normalized value of Sun and McDonough (1989). 5 PM denotes primitive mantle-normalized value of Sun and McDonough (1989). Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 98\u00C2\u00A0 \u00C2\u00A0 show\u00C2\u00A0broadly\u00C2\u00A0similar\u00C2\u00A0patterns\u00C2\u00A0for\u00C2\u00A0all\u00C2\u00A0felsic\u00C2\u00A0rocks\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation.\u00C2\u00A0\u00C2\u00A0 Pronounced\u00C2\u00A0negative\u00C2\u00A0Ti\u00C2\u00A0(Ti/Ti*=0.1\u00C2\u00A0to\u00C2\u00A00.2)\u00C2\u00A0and\u00C2\u00A0Nb\u00C2\u00A0anomalies\u00C2\u00A0(Nb/Nb*=0.1\u00E2\u0080\u00900.3)\u00C2\u00A0are\u00C2\u00A0ubiquitous.\u00C2\u00A0\u00C2\u00A0 Transition\u00C2\u00A0metals\u00C2\u00A0(e.g.,\u00C2\u00A0Al,\u00C2\u00A0Sc,\u00C2\u00A0V)\u00C2\u00A0are\u00C2\u00A0also\u00C2\u00A0strongly\u00C2\u00A0depleted.\u00C2\u00A0\u00C2\u00A0With\u00C2\u00A0one\u00C2\u00A0exception,\u00C2\u00A0this\u00C2\u00A0group\u00C2\u00A0 displays\u00C2\u00A0moderate\u00C2\u00A0LREE\u00C2\u00A0fractionation\u00C2\u00A0[(La/Yb)N\u00C2\u00A0=\u00C2\u00A01.2\u00E2\u0080\u00906.6)]\u00C2\u00A0and\u00C2\u00A0moderate\u00C2\u00A0Zr/Y\u00C2\u00A0ratios\u00C2\u00A0(3.0\u00E2\u0080\u00907.1),\u00C2\u00A0 consistent\u00C2\u00A0with\u00C2\u00A0transitional\u00C2\u00A0affinities.\u00C2\u00A0All\u00C2\u00A0samples\u00C2\u00A0display\u00C2\u00A0positive\u00C2\u00A0Zr\u00C2\u00A0(Zr/Zr*\u00C2\u00A0=\u00C2\u00A01.0\u00E2\u0080\u00902.2)\u00C2\u00A0and\u00C2\u00A0Hf\u00C2\u00A0 (Hf/Hf*\u00C2\u00A0=\u00C2\u00A01.0\u00E2\u0080\u00902.5)\u00C2\u00A0anomalies.\u00C2\u00A0\u00C2\u00A0LFSE\u00E2\u0080\u0090enrichment\u00C2\u00A0is\u00C2\u00A0evident\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0high\u00C2\u00A0Th\u00C2\u00A0contents\u00C2\u00A0relative\u00C2\u00A0to\u00C2\u00A0 LREE\u00C2\u00A0[(Th/La)PM\u00C2\u00A0=\u00C2\u00A01.5\u00E2\u0080\u00905.7].\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0Strong\u00C2\u00A0Eu\u00C2\u00A0depletion\u00C2\u00A0is\u00C2\u00A0evident\u00C2\u00A0in\u00C2\u00A0all\u00C2\u00A0samples\u00C2\u00A0(Eu/Eu*\u00C2\u00A0=\u00C2\u00A00.4\u00E2\u0080\u00900.9).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 4.5.3.2\u00C2\u00A0Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation\u00C2\u00A0 The\u00C2\u00A0Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation\u00C2\u00A0includes\u00C2\u00A0mafic\u00C2\u00A0compositions\u00C2\u00A0only\u00C2\u00A0(basalt,\u00C2\u00A0minor\u00C2\u00A0basaltic\u00E2\u0080\u0090 andesite)\u00C2\u00A0with\u00C2\u00A0relatively\u00C2\u00A0low\u00C2\u00A0alkali\u00C2\u00A0contents\u00C2\u00A0and\u00C2\u00A0low\u00C2\u00A0Nb/Y\u00C2\u00A0(~0.04),\u00C2\u00A0indicating\u00C2\u00A0a\u00C2\u00A0strongly\u00C2\u00A0 subalkaline\u00C2\u00A0affinity\u00C2\u00A0(Fig.\u00C2\u00A04.6\u00C2\u00A0A,B).\u00C2\u00A0\u00C2\u00A0All\u00C2\u00A0samples\u00C2\u00A0plot\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0tholeiitic\u00C2\u00A0field\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0AFM\u00C2\u00A0diagram\u00C2\u00A0 (Fig.\u00C2\u00A04.6C).\u00C2\u00A0\u00C2\u00A0Basalt\u00C2\u00A0yields\u00C2\u00A0relatively\u00C2\u00A0low\u00C2\u00A0MgO,\u00C2\u00A0Ni,\u00C2\u00A0and\u00C2\u00A0Cr\u00C2\u00A0suggesting\u00C2\u00A0a\u00C2\u00A0relatively\u00C2\u00A0fractionated\u00C2\u00A0suite\u00C2\u00A0 (Fig.\u00C2\u00A04.7A\u00E2\u0080\u0090C),\u00C2\u00A0and\u00C2\u00A0moderate\u00E2\u0080\u0090high\u00C2\u00A0V\u00C2\u00A0contents\u00C2\u00A0are\u00C2\u00A0consistent\u00C2\u00A0with\u00C2\u00A0a\u00C2\u00A0tholeiitic\u00C2\u00A0affinity\u00C2\u00A0(Fig\u00C2\u00A04.7d).\u00C2\u00A0\u00C2\u00A0 Relatively\u00C2\u00A0low\u00C2\u00A0HFSE\u00C2\u00A0and\u00C2\u00A0LFSE\u00C2\u00A0contents\u00C2\u00A0and\u00C2\u00A0high\u00C2\u00A0V/Ti\u00C2\u00A0ratios\u00C2\u00A0in\u00C2\u00A0basalt\u00C2\u00A0are\u00C2\u00A0also\u00C2\u00A0consistent\u00C2\u00A0with\u00C2\u00A0 island\u00C2\u00A0arc\u00C2\u00A0tholeiites\u00C2\u00A0on\u00C2\u00A0basalt\u00C2\u00A0discrimination\u00C2\u00A0diagrams\u00C2\u00A0(Fig\u00C2\u00A04.8A\u00E2\u0080\u0090D).\u00C2\u00A0\u00C2\u00A0REE\u00C2\u00A0abundances\u00C2\u00A0are\u00C2\u00A0similar\u00C2\u00A0 to\u00C2\u00A0basalt\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0formation\u00C2\u00A0(Yb*\u00C2\u00A0=\u00C2\u00A04\u00E2\u0080\u009012)\u00C2\u00A0but\u00C2\u00A0differ\u00C2\u00A0on\u00C2\u00A0normalized\u00C2\u00A0trace\u00C2\u00A0 element\u00C2\u00A0plots\u00C2\u00A0in\u00C2\u00A0that\u00C2\u00A0relatively\u00C2\u00A0flat\u00C2\u00A0REE\u00C2\u00A0profiles\u00C2\u00A0indicate\u00C2\u00A0only\u00C2\u00A0weak\u00C2\u00A0LREE\u00C2\u00A0fractionation\u00C2\u00A0[(La/Yb)N\u00C2\u00A0 =\u00C2\u00A00.4\u00E2\u0080\u00901.6]\u00C2\u00A0(Fig\u00C2\u00A04.9C).\u00C2\u00A0\u00C2\u00A0Basalt\u00C2\u00A0in\u00C2\u00A0this\u00C2\u00A0formation\u00C2\u00A0is\u00C2\u00A0characterized\u00C2\u00A0by\u00C2\u00A0relatively\u00C2\u00A0low\u00C2\u00A0Nb\u00C2\u00A0(Nb/Nb*=0.1\u00E2\u0080\u0090 0.4),\u00C2\u00A0low\u00C2\u00A0Ti\u00C2\u00A0(Ti/Ti*\u00C2\u00A0=\u00C2\u00A00.6\u00E2\u0080\u00901.7),\u00C2\u00A0moderate\u00C2\u00A0Zr\u00C2\u00A0(Zr/Zr*=0.6\u00E2\u0080\u00901.3),\u00C2\u00A0and\u00C2\u00A0relatively\u00C2\u00A0low\u00C2\u00A0Th\u00C2\u00A0[(Th/La)PM\u00C2\u00A0<\u00C2\u00A01].\u00C2\u00A0\u00C2\u00A0 One\u00C2\u00A0sample\u00C2\u00A0of\u00C2\u00A0basaltic\u00E2\u0080\u0090andesite\u00C2\u00A0does\u00C2\u00A0not\u00C2\u00A0vary\u00C2\u00A0significantly\u00C2\u00A0from\u00C2\u00A0basalt\u00C2\u00A0with\u00C2\u00A0respect\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0trace\u00C2\u00A0 element\u00C2\u00A0profile\u00C2\u00A0(Fig\u00C2\u00A04.9D).\u00C2\u00A0 4.5.3.3\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0 The\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0spans\u00C2\u00A0a\u00C2\u00A0range\u00C2\u00A0of\u00C2\u00A0compositions\u00C2\u00A0from\u00C2\u00A0basalt\u00C2\u00A0to\u00C2\u00A0rhyolite.\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0 rocks\u00C2\u00A0are\u00C2\u00A0characterized\u00C2\u00A0as\u00C2\u00A0subalkaline\u00C2\u00A0(low\u00C2\u00A0alkali\u00C2\u00A0contents,\u00C2\u00A0Nb/Y\u00C2\u00A0~\u00C2\u00A00.1;\u00C2\u00A0Fig\u00C2\u00A04.6\u00C2\u00A0A\u00E2\u0080\u0090B),\u00C2\u00A0and\u00C2\u00A0overlap\u00C2\u00A0 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[(La/Yb)N\u00C2\u00A0=\u00C2\u00A00.5\u00C2\u00A0to\u00C2\u00A02.6]\u00C2\u00A0and\u00C2\u00A0relatively\u00C2\u00A0low\u00C2\u00A0Zr/Y\u00C2\u00A0(1.3\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A03.0)\u00C2\u00A0in\u00C2\u00A0comparison\u00C2\u00A0to\u00C2\u00A0basalt\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0above\u00C2\u00A0 mentioned\u00C2\u00A0formations.\u00C2\u00A0 Basaltic\u00E2\u0080\u0090andesite\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0yields\u00C2\u00A0normalized\u00C2\u00A0trace\u00C2\u00A0element\u00C2\u00A0profiles\u00C2\u00A0quite\u00C2\u00A0 different\u00C2\u00A0from\u00C2\u00A0associated\u00C2\u00A0basalt\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0same\u00C2\u00A0formation.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0notable\u00C2\u00A0differences\u00C2\u00A0include\u00C2\u00A0 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those\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation.\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0rocks\u00C2\u00A0yield\u00C2\u00A0low\u00C2\u00A0HFSE\u00C2\u00A0contents\u00C2\u00A0and\u00C2\u00A0in\u00C2\u00A0Zr\u00C2\u00A0 versus\u00C2\u00A0Ga/Al\u00C2\u00A0and\u00C2\u00A0Nb\u00C2\u00A0versus\u00C2\u00A0Y\u00C2\u00A0plots\u00C2\u00A0fall\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0field\u00C2\u00A0of\u00C2\u00A0M\u00E2\u0080\u0090type\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0rocks\u00C2\u00A0(Fig\u00C2\u00A04.11\u00C2\u00A0A,\u00C2\u00A0 B).\u00C2\u00A0\u00C2\u00A0Primitive\u00C2\u00A0mantle\u00E2\u0080\u0090normalized\u00C2\u00A0extended\u00C2\u00A0trace\u00C2\u00A0element\u00C2\u00A0plots\u00C2\u00A0(Fig\u00C2\u00A04.12B)\u00C2\u00A0are\u00C2\u00A0fairly\u00C2\u00A0uniform\u00C2\u00A0for\u00C2\u00A0 all\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0from\u00C2\u00A0this\u00C2\u00A0formation\u00C2\u00A0and\u00C2\u00A0display\u00C2\u00A0pronounced\u00C2\u00A0negative\u00C2\u00A0Ti\u00C2\u00A0(Ti/Ti*\u00C2\u00A0=\u00C2\u00A00.04\u00C2\u00A0to\u00C2\u00A0 0.3)\u00C2\u00A0and\u00C2\u00A0Nb\u00C2\u00A0anomalies\u00C2\u00A0(Nb/Nb*\u00C2\u00A0=\u00C2\u00A00.03\u00E2\u0080\u00900.3)\u00C2\u00A0and\u00C2\u00A0depleted\u00C2\u00A0transition\u00C2\u00A0metal\u00C2\u00A0(e.g.,\u00C2\u00A0Al,\u00C2\u00A0V\u00C2\u00A0contents).\u00C2\u00A0\u00C2\u00A0 Most\u00C2\u00A0samples\u00C2\u00A0yield\u00C2\u00A0modest\u00C2\u00A0LREE\u00C2\u00A0fractionation\u00C2\u00A0[(La/Yb)N\u00C2\u00A0=\u00C2\u00A00.9\u00E2\u0080\u00906.1].\u00C2\u00A0\u00C2\u00A0Nearly\u00C2\u00A0all\u00C2\u00A0samples\u00C2\u00A0have\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 100\u00C2\u00A0 \u00C2\u00A0 positive\u00C2\u00A0Zr\u00C2\u00A0(Zr/Zr*\u00C2\u00A0=\u00C2\u00A00.6\u00E2\u0080\u00902.2)\u00C2\u00A0and\u00C2\u00A0Hf\u00C2\u00A0(Hf/Hf*\u00C2\u00A0=\u00C2\u00A00.9\u00C2\u00A0\u00E2\u0080\u00902.4)\u00C2\u00A0anomalies.\u00C2\u00A0\u00C2\u00A0LFSE\u00E2\u0080\u0090enrichment\u00C2\u00A0is\u00C2\u00A0evident\u00C2\u00A0in\u00C2\u00A0 the\u00C2\u00A0high\u00C2\u00A0Th\u00C2\u00A0contents\u00C2\u00A0relative\u00C2\u00A0to\u00C2\u00A0LREE\u00C2\u00A0[(Th/La)PM\u00C2\u00A0=\u00C2\u00A01.5\u00E2\u0080\u00904.4],\u00C2\u00A0noting\u00C2\u00A0one\u00C2\u00A0exception.\u00C2\u00A0\u00C2\u00A0Negative\u00C2\u00A0Eu\u00C2\u00A0 anomalies\u00C2\u00A0are\u00C2\u00A0a\u00C2\u00A0feature\u00C2\u00A0of\u00C2\u00A0all\u00C2\u00A0felsic\u00C2\u00A0rocks\u00C2\u00A0from\u00C2\u00A0this\u00C2\u00A0formation\u00C2\u00A0(Eu/Eu*\u00C2\u00A0=\u00C2\u00A00.3\u00E2\u0080\u00901.0).\u00C2\u00A0 4.5.3.4\u00C2\u00A0Chemostratigraphy\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0VMS\u00E2\u0080\u0090Host\u00C2\u00A0sequence\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Geologic\u00C2\u00A0sections\u00C2\u00A0are\u00C2\u00A0well\u00C2\u00A0constrained\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0VMS\u00E2\u0080\u0090bearing\u00C2\u00A0volcanic\u00C2\u00A0sequence\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0and\u00C2\u00A0provide\u00C2\u00A0a\u00C2\u00A0framework\u00C2\u00A0for\u00C2\u00A0a\u00C2\u00A0chemostratigraphic\u00C2\u00A0model\u00C2\u00A0(Chap.\u00C2\u00A0 2;\u00C2\u00A0Fig\u00C2\u00A04.5).\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0unit\u00E2\u0080\u0090scale\u00C2\u00A0evaluation\u00C2\u00A0permits\u00C2\u00A0a\u00C2\u00A0study\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0geochemical\u00C2\u00A0variation\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0 volcanic\u00C2\u00A0complex\u00C2\u00A0and\u00C2\u00A0is\u00C2\u00A0used\u00C2\u00A0to\u00C2\u00A0investigate\u00C2\u00A0the\u00C2\u00A0potential\u00C2\u00A0links\u00C2\u00A0between\u00C2\u00A0the\u00C2\u00A0petrogenesis\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 volcanic\u00C2\u00A0suite\u00C2\u00A0and\u00C2\u00A0generation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0dacite\u00E2\u0080\u0090rhyolite\u00C2\u00A0suite\u00C2\u00A0encompasses\u00C2\u00A0several\u00C2\u00A0geochemically\u00C2\u00A0distinctive\u00C2\u00A0units,\u00C2\u00A0including\u00C2\u00A0a\u00C2\u00A0 syn\u00E2\u0080\u0090mineralization\u00C2\u00A0rhyolite\u00C2\u00A0flow\u00E2\u0080\u0090dome\u00C2\u00A0complex,\u00C2\u00A0a\u00C2\u00A0hanging\u00C2\u00A0wall\u00C2\u00A0dacite\u00C2\u00A0unit,\u00C2\u00A0and\u00C2\u00A0post\u00E2\u0080\u0090 mineralization\u00C2\u00A0quartz\u00E2\u0080\u0090phyric\u00C2\u00A0rhyolite\u00C2\u00A0dykes\u00C2\u00A0(Chap.\u00C2\u00A02).\u00C2\u00A0\u00C2\u00A0Basalt\u00C2\u00A0forms\u00C2\u00A0almost\u00C2\u00A0the\u00C2\u00A0entirety\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 footwall\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0majority\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0hanging\u00C2\u00A0wall.\u00C2\u00A0 SiO2\u00C2\u00A0contents\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0basalt\u00C2\u00A0units\u00C2\u00A0range\u00C2\u00A0from\u00C2\u00A045.32\u00C2\u00A0to\u00C2\u00A053.48\u00C2\u00A0wt.%,\u00C2\u00A0dacite\u00C2\u00A0yields\u00C2\u00A065.35\u00C2\u00A0to\u00C2\u00A0 66.54\u00C2\u00A0wt.%\u00C2\u00A0SiO2\u00C2\u00A0and\u00C2\u00A0rhyolite\u00C2\u00A0has\u00C2\u00A068.18\u00C2\u00A0to\u00C2\u00A075.16\u00C2\u00A0wt.%\u00C2\u00A0SiO2\u00C2\u00A0(Figs.\u00C2\u00A04.13A).\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0compositional\u00C2\u00A0 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for\u00C2\u00A0these\u00C2\u00A0early\u00E2\u0080\u0090rift\u00C2\u00A0lavas.\u00C2\u00A0\u00C2\u00A0\u00E2\u0080\u0098Primitive\u00E2\u0080\u0099\u00C2\u00A0arc\u00C2\u00A0magmas\u00C2\u00A0are\u00C2\u00A0those\u00C2\u00A0with\u00C2\u00A0up\u00C2\u00A0to\u00C2\u00A08\u00C2\u00A0wt%\u00C2\u00A0MgO\u00C2\u00A0in\u00C2\u00A0oceanic\u00C2\u00A0 arcs,\u00C2\u00A0and\u00C2\u00A0lower\u00C2\u00A0values\u00C2\u00A0for\u00C2\u00A0mature\u00C2\u00A0arcs\u00C2\u00A0(Leate\u00C2\u00A0and\u00C2\u00A0Larter,\u00C2\u00A02003).\u00C2\u00A0\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0 basalt\u00C2\u00A0averages\u00C2\u00A07.4\u00C2\u00A0\u00C2\u00B14.4\u00C2\u00A0wt%\u00C2\u00A0MgO,\u00C2\u00A0compared\u00C2\u00A0to\u00C2\u00A04.7\u00C2\u00A0\u00C2\u00B11.8\u00C2\u00A0wt%\u00C2\u00A0and\u00C2\u00A03.9\u00C2\u00A0wt%\u00C2\u00A0MgO\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0younger\u00C2\u00A0 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thicker\u00C2\u00A0crust\u00C2\u00A0(Green,\u00C2\u00A01980;\u00C2\u00A0Gill,\u00C2\u00A01981)\u00C2\u00A0during\u00C2\u00A0the\u00C2\u00A0waning\u00C2\u00A0stages\u00C2\u00A0of\u00C2\u00A0arc\u00C2\u00A0rifting.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0data\u00C2\u00A0suggest\u00C2\u00A0 phase\u00C2\u00A01\u00C2\u00A0was\u00C2\u00A0a\u00C2\u00A0period\u00C2\u00A0of\u00C2\u00A0maximum\u00C2\u00A0extension,\u00C2\u00A0rifting,\u00C2\u00A0and\u00C2\u00A0subsidence,\u00C2\u00A0with\u00C2\u00A0relatively\u00C2\u00A0thin\u00C2\u00A0arc\u00C2\u00A0 crust\u00C2\u00A0and\u00C2\u00A0high\u00C2\u00A0heat\u00C2\u00A0flow,\u00C2\u00A0and\u00C2\u00A0therefore\u00C2\u00A0conducive\u00C2\u00A0to\u00C2\u00A0VMS\u00C2\u00A0formation.\u00C2\u00A0 4.6.2\u00C2\u00A0 Felsic\u00C2\u00A0Volcanic\u00C2\u00A0Rock\u00C2\u00A0Petrochemistry\u00C2\u00A0and\u00C2\u00A0Association\u00C2\u00A0with\u00C2\u00A0VMS\u00C2\u00A0\u00C2\u00A0 Dacitic\u00C2\u00A0to\u00C2\u00A0rhyolitic\u00C2\u00A0rocks\u00C2\u00A0occur\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0and\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formations,\u00C2\u00A0but\u00C2\u00A0are\u00C2\u00A0 absent\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation.\u00C2\u00A0\u00C2\u00A0Felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0from\u00C2\u00A0these\u00C2\u00A0formations\u00C2\u00A0are\u00C2\u00A0almost\u00C2\u00A0 all\u00C2\u00A0subalkaline\u00C2\u00A0and\u00C2\u00A0show\u00C2\u00A0broadly\u00C2\u00A0similar\u00C2\u00A0patterns\u00C2\u00A0on\u00C2\u00A0normalized\u00C2\u00A0trace\u00C2\u00A0element\u00C2\u00A0plots.\u00C2\u00A0\u00C2\u00A0 Pronounced\u00C2\u00A0negative\u00C2\u00A0Ti\u00C2\u00A0and\u00C2\u00A0Nb\u00C2\u00A0anomalies\u00C2\u00A0are\u00C2\u00A0ubiquitous\u00C2\u00A0and\u00C2\u00A0transition\u00C2\u00A0metals\u00C2\u00A0(e.g.,\u00C2\u00A0Al,\u00C2\u00A0Sc,\u00C2\u00A0and\u00C2\u00A0 V)\u00C2\u00A0are\u00C2\u00A0also\u00C2\u00A0strongly\u00C2\u00A0depleted.\u00C2\u00A0\u00C2\u00A0With\u00C2\u00A0minor\u00C2\u00A0exceptions,\u00C2\u00A0nearly\u00C2\u00A0all\u00C2\u00A0samples\u00C2\u00A0have\u00C2\u00A0positive\u00C2\u00A0Zr\u00C2\u00A0and\u00C2\u00A0Hf\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 104\u00C2\u00A0 \u00C2\u00A0 anomalies.\u00C2\u00A0\u00C2\u00A0LFSE\u00E2\u0080\u0090enrichment\u00C2\u00A0is\u00C2\u00A0evident\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0high\u00C2\u00A0Th\u00C2\u00A0contents\u00C2\u00A0relative\u00C2\u00A0to\u00C2\u00A0LREE\u00C2\u00A0and\u00C2\u00A0HFSE.\u00C2\u00A0\u00C2\u00A0Weak\u00C2\u00A0 to\u00C2\u00A0moderate\u00C2\u00A0negative\u00C2\u00A0Eu\u00C2\u00A0anomalies\u00C2\u00A0and\u00C2\u00A0moderate\u00C2\u00A0LREE/HREE\u00C2\u00A0ratios\u00C2\u00A0are\u00C2\u00A0characteristic\u00C2\u00A0of\u00C2\u00A0nearly\u00C2\u00A0 all\u00C2\u00A0samples.\u00C2\u00A0\u00C2\u00A0There\u00C2\u00A0are\u00C2\u00A0slight\u00C2\u00A0variations\u00C2\u00A0in\u00C2\u00A0mean\u00C2\u00A0Zr/TiO2\u00C2\u00A0ratios,\u00C2\u00A0with\u00C2\u00A0ratios\u00C2\u00A0slightly\u00C2\u00A0higher\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0(674\u00C2\u00A0\u00C2\u00B1314)\u00C2\u00A0than\u00C2\u00A0those\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation\u00C2\u00A0(422\u00C2\u00A0\u00C2\u00B1341).\u00C2\u00A0\u00C2\u00A0 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with\u00C2\u00A0some\u00C2\u00A0influence\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0continental\u00C2\u00A0crust\u00C2\u00A0(Pitcher,\u00C2\u00A01983;\u00C2\u00A0Whalen,\u00C2\u00A01985).\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0a\u00C2\u00A0mantle\u00C2\u00A0 source\u00C2\u00A0scenario,\u00C2\u00A0the\u00C2\u00A0felsic\u00C2\u00A0rocks\u00C2\u00A0were\u00C2\u00A0likely\u00C2\u00A0derived\u00C2\u00A0via\u00C2\u00A0fractionation\u00C2\u00A0of\u00C2\u00A0an\u00C2\u00A0arc\u00C2\u00A0basaltic\u00C2\u00A0melt,\u00C2\u00A0 though\u00C2\u00A0the\u00C2\u00A0general\u00C2\u00A0lack\u00C2\u00A0of\u00C2\u00A0abundant\u00C2\u00A0intermediate\u00C2\u00A0compositions\u00C2\u00A0suggests\u00C2\u00A0this\u00C2\u00A0is\u00C2\u00A0not\u00C2\u00A0likely\u00C2\u00A0the\u00C2\u00A0 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and\u00C2\u00A0Yb\u00E2\u0080\u0090depleted\u00C2\u00A0rhyolite\u00C2\u00A0is\u00C2\u00A0defined\u00C2\u00A0as\u00C2\u00A0FIV\u00C2\u00A0(Hart\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02004).\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0compositions\u00C2\u00A0approximate\u00C2\u00A0 partial\u00C2\u00A0melting\u00C2\u00A0of\u00C2\u00A0hydrous\u00C2\u00A0mafic\u00C2\u00A0crust\u00C2\u00A0or\u00C2\u00A0amphibolite\u00C2\u00A0at\u00C2\u00A0relatively\u00C2\u00A0high\u00C2\u00A0temperature\u00C2\u00A0and\u00C2\u00A0low\u00C2\u00A0 pressure\u00C2\u00A0conditions,\u00C2\u00A0in\u00C2\u00A0equilibrium\u00C2\u00A0with\u00C2\u00A0hornblende\u00C2\u00A0(clinopyroxene\u00C2\u00A0at\u00C2\u00A0higher\u00C2\u00A0temperatures)\u00C2\u00A0 and\u00C2\u00A0plagioclase\u00C2\u00A0(Beard\u00C2\u00A0and\u00C2\u00A0Lofgren,\u00C2\u00A01991;\u00C2\u00A0Wolf\u00C2\u00A0and\u00C2\u00A0Wyllie,\u00C2\u00A01994).\u00C2\u00A0\u00C2\u00A0As\u00C2\u00A0the\u00C2\u00A0REE\u00C2\u00A0are\u00C2\u00A0moderately\u00C2\u00A0 to\u00C2\u00A0strongly\u00C2\u00A0incompatible\u00C2\u00A0in\u00C2\u00A0this\u00C2\u00A0phase\u00C2\u00A0assemblage,\u00C2\u00A0REE\u00C2\u00A0abundances\u00C2\u00A0tend\u00C2\u00A0to\u00C2\u00A0be\u00C2\u00A0relatively\u00C2\u00A0high\u00C2\u00A0in\u00C2\u00A0 the\u00C2\u00A0melt,\u00C2\u00A0though\u00C2\u00A0strong\u00C2\u00A0partitioning\u00C2\u00A0of\u00C2\u00A0Eu\u00C2\u00A0into\u00C2\u00A0plagioclase\u00C2\u00A0is\u00C2\u00A0likely\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0low\u00C2\u00A0\u00C6\u0092O2.\u00C2\u00A0 FII\u00C2\u00A0rhyolites\u00C2\u00A0appear\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0dominant\u00C2\u00A0VMS\u00E2\u0080\u0090bearing\u00C2\u00A0class\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Phanerozoic\u00C2\u00A0and\u00C2\u00A0Proterozoic,\u00C2\u00A0 not\u00C2\u00A0because\u00C2\u00A0of\u00C2\u00A0differences\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0generation\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0systems,\u00C2\u00A0but\u00C2\u00A0because\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0evolution\u00C2\u00A0of\u00C2\u00A0 plate\u00C2\u00A0tectonics\u00C2\u00A0and\u00C2\u00A0variation\u00C2\u00A0in\u00C2\u00A0petrogenesis\u00C2\u00A0of\u00C2\u00A0felsic\u00C2\u00A0magmas\u00C2\u00A0in\u00C2\u00A0these\u00C2\u00A0terrains\u00C2\u00A0(Lesher\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A0 1986;\u00C2\u00A0Lentz,\u00C2\u00A01998).\u00C2\u00A0\u00C2\u00A0Piercey\u00C2\u00A0(2007)\u00C2\u00A0illustrates\u00C2\u00A0that\u00C2\u00A0the\u00C2\u00A0petrochemical\u00C2\u00A0classification\u00C2\u00A0of\u00C2\u00A0rhyolites\u00C2\u00A0 in\u00C2\u00A0post\u00E2\u0080\u0090Archean\u00C2\u00A0terrains\u00C2\u00A0is\u00C2\u00A0dependent\u00C2\u00A0on\u00C2\u00A0whether\u00C2\u00A0the\u00C2\u00A0magmas\u00C2\u00A0were\u00C2\u00A0generated\u00C2\u00A0in\u00C2\u00A0juvenile\u00C2\u00A0or\u00C2\u00A0 evolved\u00C2\u00A0environments.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0post\u00E2\u0080\u0090Archean\u00C2\u00A0evolved\u00C2\u00A0terrains,\u00C2\u00A0most\u00C2\u00A0VMS\u00E2\u0080\u0090associated\u00C2\u00A0rhyolites\u00C2\u00A0are\u00C2\u00A0 calc\u00E2\u0080\u0090alkalic\u00C2\u00A0FII\u00E2\u0080\u0090FIII,\u00C2\u00A0though\u00C2\u00A0some\u00C2\u00A0are\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0FI\u00C2\u00A0(Piercey,\u00C2\u00A02007).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0post\u00E2\u0080\u0090Archean\u00C2\u00A0 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resemble\u00C2\u00A0the\u00C2\u00A0Mt.\u00C2\u00A0Windsor\u00C2\u00A0and\u00C2\u00A0Kuroko\u00C2\u00A0districts,\u00C2\u00A0examples\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0back\u00E2\u0080\u0090arc\u00C2\u00A0or\u00C2\u00A0intra\u00E2\u0080\u0090arc\u00C2\u00A0rift\u00C2\u00A0settings\u00C2\u00A0 with\u00C2\u00A0continental\u00C2\u00A0basement\u00C2\u00A0(Fig.\u00C2\u00A04.16E\u00E2\u0080\u0090F).\u00C2\u00A0\u00C2\u00A0Considering\u00C2\u00A0the\u00C2\u00A0inherited\u00C2\u00A0Proterozoic\u00C2\u00A0zircons\u00C2\u00A0(Chap.\u00C2\u00A0 2)\u00C2\u00A0and\u00C2\u00A0evolved\u00C2\u00A0Nd\u00C2\u00A0and\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0signatures\u00C2\u00A0of\u00C2\u00A0felsic\u00C2\u00A0rocks\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0(Chap.\u00C2\u00A05),\u00C2\u00A0there\u00C2\u00A0is\u00C2\u00A0 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hydrothermal\u00C2\u00A0venting\u00C2\u00A0and\u00C2\u00A0VMS\u00C2\u00A0formation\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0seafloor.\u00C2\u00A0\u00C2\u00A0Some\u00C2\u00A0models\u00C2\u00A0propose\u00C2\u00A0that\u00C2\u00A0a\u00C2\u00A0rapid\u00C2\u00A0 ascent\u00C2\u00A0of\u00C2\u00A0high\u00E2\u0080\u0090temperate\u00C2\u00A0felsic\u00C2\u00A0magma\u00C2\u00A0to\u00C2\u00A0surficial\u00C2\u00A0environment\u00C2\u00A0enhances\u00C2\u00A0VMS\u00C2\u00A0formation\u00C2\u00A0by\u00C2\u00A0 driving\u00C2\u00A0the\u00C2\u00A0hydrothermal\u00C2\u00A0system\u00C2\u00A0(e.g.,\u00C2\u00A0Barrie\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01999.\u00C2\u00A0\u00C2\u00A0However,\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0VMS\u00C2\u00A0genesis\u00C2\u00A0model\u00C2\u00A0 proposed\u00C2\u00A0in\u00C2\u00A0Chapter\u00C2\u00A05,\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0have\u00C2\u00A0a\u00C2\u00A0passive\u00C2\u00A0genetic\u00C2\u00A0role\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0formation\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0 deposits\u00C2\u00A0at\u00C2\u00A0Tambogrande.\u00C2\u00A0\u00C2\u00A0Rather,\u00C2\u00A0high\u00C2\u00A0temperature\u00C2\u00A0felsic\u00C2\u00A0volcanism\u00C2\u00A0is\u00C2\u00A0symptomatic\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 anomalous\u00C2\u00A0tectonic\u00C2\u00A0and\u00C2\u00A0geothermal\u00C2\u00A0setting.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0is\u00C2\u00A0supported\u00C2\u00A0by\u00C2\u00A0the\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0data\u00C2\u00A0which\u00C2\u00A0 yield\u00C2\u00A0distinctively\u00C2\u00A0different\u00C2\u00A0isotopic\u00C2\u00A0signatures\u00C2\u00A0for\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0mineralization\u00C2\u00A0and\u00C2\u00A0felsic\u00C2\u00A0 volcanic\u00C2\u00A0rock\u00C2\u00A0(Chap.\u00C2\u00A05).\u00C2\u00A0 4.6.3\u00C2\u00A0 Implications\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0Tectonic\u00C2\u00A0Setting\u00C2\u00A0 The\u00C2\u00A0petrochemical\u00C2\u00A0volcanic\u00C2\u00A0rock\u00C2\u00A0assemblages\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0suggest\u00C2\u00A0oceanic\u00C2\u00A0island\u00C2\u00A0 arc\u00C2\u00A0geochemical\u00C2\u00A0affinities.\u00C2\u00A0\u00C2\u00A0For\u00C2\u00A0the\u00C2\u00A0generation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0mafic\u00C2\u00A0volcanic\u00C2\u00A0rocks,\u00C2\u00A0partial\u00C2\u00A0melting\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0 depleted\u00C2\u00A0mantle\u00C2\u00A0or\u00C2\u00A0MORB\u00E2\u0080\u0090type\u00C2\u00A0source\u00C2\u00A0(i.e.,\u00C2\u00A0the\u00C2\u00A0mantle\u00C2\u00A0wedge)\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0influence\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0slab\u00E2\u0080\u0090 derived\u00C2\u00A0\u00E2\u0080\u0098fluid\u00E2\u0080\u0099\u00C2\u00A0component\u00C2\u00A0is\u00C2\u00A0inferred\u00C2\u00A0and\u00C2\u00A0is\u00C2\u00A0the\u00C2\u00A0principal\u00C2\u00A0process\u00C2\u00A0accepted\u00C2\u00A0in\u00C2\u00A0arc\u00C2\u00A0volcanic\u00C2\u00A0 settings\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0genesis\u00C2\u00A0of\u00C2\u00A0basalts\u00C2\u00A0of\u00C2\u00A0arc\u00C2\u00A0tholeiitic\u00C2\u00A0to\u00C2\u00A0calc\u00E2\u0080\u0090alkalic\u00C2\u00A0affinity\u00C2\u00A0(McCulloch\u00C2\u00A0and\u00C2\u00A0Gamble,\u00C2\u00A0 1991;\u00C2\u00A0Hawkesworth\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01993;\u00C2\u00A0Pearce\u00C2\u00A0and\u00C2\u00A0Parkinson,\u00C2\u00A01993;\u00C2\u00A0Pearce\u00C2\u00A0and\u00C2\u00A0Peate,\u00C2\u00A01995).\u00C2\u00A0 According\u00C2\u00A0to\u00C2\u00A0HFSE\u00C2\u00A0systematics,\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0are\u00C2\u00A0dominantly\u00C2\u00A0 M\u00E2\u0080\u0090type\u00C2\u00A0(direct\u00C2\u00A0mantle\u00C2\u00A0source)\u00C2\u00A0transitional\u00C2\u00A0to\u00C2\u00A0I\u00E2\u0080\u0090type\u00C2\u00A0(mafic,\u00C2\u00A0indirect\u00C2\u00A0mantle\u00E2\u0080\u0090derived\u00C2\u00A0source,\u00C2\u00A0e.g.,\u00C2\u00A0 subcrustal\u00C2\u00A0underplate),\u00C2\u00A0typical\u00C2\u00A0of\u00C2\u00A0oceanic\u00C2\u00A0island\u00C2\u00A0arc\u00C2\u00A0terrains\u00C2\u00A0(Pitcher,\u00C2\u00A01983;\u00C2\u00A0Whalen,\u00C2\u00A01985).\u00C2\u00A0\u00C2\u00A0 Geochemical\u00C2\u00A0data,\u00C2\u00A0such\u00C2\u00A0as\u00C2\u00A0variable\u00C2\u00A0HFSE\u00C2\u00A0(Zr,\u00C2\u00A0Y,\u00C2\u00A0Nb),\u00C2\u00A0LFSE\u00C2\u00A0(Th)\u00C2\u00A0and\u00C2\u00A0REE\u00C2\u00A0implicate\u00C2\u00A0continental\u00C2\u00A0 crust\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0generation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0source\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0Therefore,\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0 was\u00C2\u00A0developed\u00C2\u00A0as\u00C2\u00A0a\u00C2\u00A0\u00E2\u0080\u0098continental\u00C2\u00A0margin\u00C2\u00A0arc\u00E2\u0080\u0090rift\u00E2\u0080\u0099\u00C2\u00A0but\u00C2\u00A0resembles\u00C2\u00A0many\u00C2\u00A0modern\u00C2\u00A0oceanic\u00C2\u00A0island\u00C2\u00A0arc\u00C2\u00A0 rifts\u00C2\u00A0or\u00C2\u00A0possible\u00C2\u00A0nascent\u00C2\u00A0back\u00E2\u0080\u0090arcs.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 In\u00C2\u00A0order\u00C2\u00A0to\u00C2\u00A0generate\u00C2\u00A0oceanic\u00C2\u00A0arc\u00C2\u00A0petrochemical\u00C2\u00A0affinities\u00C2\u00A0for\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0continental\u00C2\u00A0 margin\u00C2\u00A0setting,\u00C2\u00A0crustal\u00C2\u00A0thickness\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0overriding\u00C2\u00A0plate\u00C2\u00A0must\u00C2\u00A0have\u00C2\u00A0been\u00C2\u00A0sufficiently\u00C2\u00A0thin\u00C2\u00A0to\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 108\u00C2\u00A0 \u00C2\u00A0 allow\u00C2\u00A0for\u00C2\u00A0limited\u00C2\u00A0modification\u00C2\u00A0of\u00C2\u00A0ascending\u00C2\u00A0mantle\u00E2\u0080\u0090derived\u00C2\u00A0magmas.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0was\u00C2\u00A0likely\u00C2\u00A0the\u00C2\u00A0case\u00C2\u00A0 along\u00C2\u00A0the\u00C2\u00A0western\u00C2\u00A0Peruvian\u00C2\u00A0margin\u00C2\u00A0during\u00C2\u00A0the\u00C2\u00A0Cretaceous\u00C2\u00A0when\u00C2\u00A0the\u00C2\u00A0Andean\u00C2\u00A0orogeny\u00C2\u00A0was\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0 incipient\u00C2\u00A0stages\u00C2\u00A0of\u00C2\u00A0development\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0leading\u00C2\u00A0edge\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0continental\u00C2\u00A0crust\u00C2\u00A0was\u00C2\u00A0much\u00C2\u00A0 thinner\u00C2\u00A0than\u00C2\u00A0at\u00C2\u00A0present\u00C2\u00A0(Benavides\u00E2\u0080\u0090C\u00C3\u00A1ceres,\u00C2\u00A01999).\u00C2\u00A0\u00C2\u00A0Moreover,\u00C2\u00A0the\u00C2\u00A0newly\u00C2\u00A0developed\u00C2\u00A0suture\u00C2\u00A0 bounding\u00C2\u00A0the\u00C2\u00A0Amotape\u00C2\u00A0allocthon\u00C2\u00A0during\u00C2\u00A0the\u00C2\u00A0Early\u00C2\u00A0Cretaceous\u00C2\u00A0likely\u00C2\u00A0provided\u00C2\u00A0a\u00C2\u00A0zone\u00C2\u00A0of\u00C2\u00A0crustal\u00C2\u00A0 weakness\u00C2\u00A0along\u00C2\u00A0which\u00C2\u00A0rifting\u00C2\u00A0occurred.\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0composite\u00C2\u00A0margin\u00C2\u00A0with\u00C2\u00A0inherent\u00C2\u00A0structural\u00C2\u00A0 weaknesses\u00C2\u00A0would\u00C2\u00A0have\u00C2\u00A0more\u00C2\u00A0easily\u00C2\u00A0enabled\u00C2\u00A0crustal\u00C2\u00A0attenuation\u00C2\u00A0and\u00C2\u00A0rifting\u00C2\u00A0than\u00C2\u00A0a\u00C2\u00A0coherent\u00C2\u00A0 zone\u00C2\u00A0of\u00C2\u00A0uniform\u00C2\u00A0crustal\u00C2\u00A0composition.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Given\u00C2\u00A0that\u00C2\u00A0back\u00E2\u0080\u0090arc\u00C2\u00A0basin\u00C2\u00A0basalts\u00C2\u00A0can\u00C2\u00A0show\u00C2\u00A0a\u00C2\u00A0geochemically\u00C2\u00A0continuity\u00C2\u00A0with\u00C2\u00A0island\u00C2\u00A0arc\u00C2\u00A0 tholeiites\u00C2\u00A0(Taylor\u00C2\u00A0and\u00C2\u00A0Martinez,\u00C2\u00A02003),\u00C2\u00A0the\u00C2\u00A0recognition\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0back\u00E2\u0080\u0090arc\u00C2\u00A0in\u00C2\u00A0ancient\u00C2\u00A0arc\u00C2\u00A0settings\u00C2\u00A0is\u00C2\u00A0a\u00C2\u00A0 somewhat\u00C2\u00A0difficult\u00C2\u00A0task.\u00C2\u00A0\u00C2\u00A0Unless\u00C2\u00A0MORB\u00E2\u0080\u0090type\u00C2\u00A0rocks\u00C2\u00A0are\u00C2\u00A0present,\u00C2\u00A0which\u00C2\u00A0imply\u00C2\u00A0well\u00C2\u00A0established\u00C2\u00A0 spreading\u00C2\u00A0away\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0arc,\u00C2\u00A0back\u00C2\u00A0arc\u00C2\u00A0processes\u00C2\u00A0are\u00C2\u00A0difficult\u00C2\u00A0to\u00C2\u00A0verify.\u00C2\u00A0\u00C2\u00A0Geochemical\u00C2\u00A0and\u00C2\u00A0 geologic\u00C2\u00A0data\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0suggest\u00C2\u00A0that\u00C2\u00A0an\u00C2\u00A0extensional\u00C2\u00A0arc\u00C2\u00A0regime\u00C2\u00A0(i.e.,\u00C2\u00A0intra\u00E2\u0080\u0090arc\u00C2\u00A0rift\u00C2\u00A0 or\u00C2\u00A0nascent\u00C2\u00A0back\u00E2\u0080\u0090arc)\u00C2\u00A0was\u00C2\u00A0responsible\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0development\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0marginal\u00C2\u00A0basin\u00C2\u00A0in\u00C2\u00A0northwestern\u00C2\u00A0 Per\u00C3\u00BA\u00C2\u00A0during\u00C2\u00A0the\u00C2\u00A0Cretaceous.\u00C2\u00A0\u00C2\u00A0No\u00C2\u00A0\u00E2\u0080\u0098non\u00E2\u0080\u0090arc\u00E2\u0080\u0099\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0(e.g.,\u00C2\u00A0MORB)\u00C2\u00A0were\u00C2\u00A0identified\u00C2\u00A0which\u00C2\u00A0 might\u00C2\u00A0indicate\u00C2\u00A0intra\u00E2\u0080\u0090continental\u00C2\u00A0rifting\u00C2\u00A0or\u00C2\u00A0back\u00C2\u00A0arc\u00C2\u00A0spreading\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0the\u00C2\u00A0 Western\u00C2\u00A0Peruvian\u00C2\u00A0Trough,\u00C2\u00A0however,\u00C2\u00A0Atherton\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1985)\u00C2\u00A0suggest\u00C2\u00A0some\u00C2\u00A0basalt\u00C2\u00A0may\u00C2\u00A0have\u00C2\u00A0 MORB\u00C2\u00A0geochemical\u00C2\u00A0characteristics\u00C2\u00A0related\u00C2\u00A0to\u00C2\u00A0incipient\u00C2\u00A0back\u00E2\u0080\u0090arc\u00C2\u00A0spreading.\u00C2\u00A0\u00C2\u00A0However,\u00C2\u00A0 Cretaceous\u00C2\u00A0intra\u00E2\u0080\u0090continental\u00C2\u00A0alkaline\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0are\u00C2\u00A0preserved\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Eastern\u00C2\u00A0Cordillera\u00C2\u00A0from\u00C2\u00A0 Ecuador\u00C2\u00A0to\u00C2\u00A0Argentina\u00C2\u00A0and\u00C2\u00A0represent\u00C2\u00A0the\u00C2\u00A0associated\u00C2\u00A0back\u00E2\u0080\u0090arc\u00C2\u00A0(Soler\u00C2\u00A0and\u00C2\u00A0Bonhomme,\u00C2\u00A01990;\u00C2\u00A0 Viramonte\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01999;\u00C2\u00A0Barrag\u00C3\u00A1n\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02005).\u00C2\u00A0\u00C2\u00A0Therefore,\u00C2\u00A0a\u00C2\u00A0rifted\u00C2\u00A0arc\u00C2\u00A0(\u00C2\u00B1\u00C2\u00A0incipient\u00C2\u00A0back\u00E2\u0080\u0090arc\u00C2\u00A0 spreading)\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0peri\u00E2\u0080\u0090continental\u00C2\u00A0setting\u00C2\u00A0is\u00C2\u00A0an\u00C2\u00A0acceptable\u00C2\u00A0analogue\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin.\u00C2\u00A0\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 109\u00C2\u00A0 \u00C2\u00A0 Extensional\u00C2\u00A0basins\u00C2\u00A0such\u00C2\u00A0as\u00C2\u00A0Bransfield\u00C2\u00A0Strait\u00C2\u00A0(Barker\u00C2\u00A0and\u00C2\u00A0Austin,\u00C2\u00A01998)\u00C2\u00A0and\u00C2\u00A0Manus\u00C2\u00A0Basin\u00C2\u00A0(Sinton\u00C2\u00A0 et\u00C2\u00A0al.,\u00C2\u00A02003)\u00C2\u00A0are\u00C2\u00A0analogous\u00C2\u00A0modern\u00C2\u00A0settings.\u00C2\u00A0 4.7\u00C2\u00A0 Summary\u00C2\u00A0 In\u00C2\u00A0summary,\u00C2\u00A0there\u00C2\u00A0are\u00C2\u00A0several\u00C2\u00A0petrochemical\u00C2\u00A0features\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0early\u00C2\u00A0rift\u00C2\u00A0stage\u00C2\u00A0volcanism\u00C2\u00A0(i.e.,\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation)\u00C2\u00A0that\u00C2\u00A0are\u00C2\u00A0indicative\u00C2\u00A0of\u00C2\u00A0favourable\u00C2\u00A0geologic\u00C2\u00A0conditions\u00C2\u00A0for\u00C2\u00A0VMS\u00C2\u00A0 formation.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0presence\u00C2\u00A0of\u00C2\u00A0petrochemically\u00C2\u00A0distinct\u00C2\u00A0syn\u00E2\u0080\u0090\u00C2\u00A0and\u00C2\u00A0post\u00E2\u0080\u0090mineralization\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0 units\u00C2\u00A0suggests\u00C2\u00A0a\u00C2\u00A0complex\u00C2\u00A0igneous\u00C2\u00A0system\u00C2\u00A0with\u00C2\u00A0multiple\u00C2\u00A0magma\u00C2\u00A0batches.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0favours\u00C2\u00A0a\u00C2\u00A0 thermally\u00C2\u00A0and\u00C2\u00A0seismically\u00C2\u00A0dynamic\u00C2\u00A0setting\u00C2\u00A0required\u00C2\u00A0to\u00C2\u00A0sustained\u00C2\u00A0hydrothermal\u00C2\u00A0circulation\u00C2\u00A0and\u00C2\u00A0 VMS\u00C2\u00A0formation.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 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derivation.\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0bimodal\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0retained\u00C2\u00A0much\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0heat\u00C2\u00A0of\u00C2\u00A0fusion\u00C2\u00A0through\u00C2\u00A0to\u00C2\u00A0 eruption\u00C2\u00A0and\u00C2\u00A0therefore\u00C2\u00A0indicate\u00C2\u00A0a\u00C2\u00A0high\u00C2\u00A0temperature\u00C2\u00A0gradient\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0crust,\u00C2\u00A0conducive\u00C2\u00A0to\u00C2\u00A0VMS\u00C2\u00A0 formation.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Phase\u00C2\u00A0I\u00C2\u00A0volcanism\u00C2\u00A0was\u00C2\u00A0associated\u00C2\u00A0was\u00C2\u00A0a\u00C2\u00A0rifting\u00C2\u00A0event\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0continental\u00C2\u00A0margin.\u00C2\u00A0\u00C2\u00A0 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Figure\u00C2\u00A04.1.\u00C2\u00A0\u00C2\u00A0Morphostructural\u00C2\u00A0units\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Peruvian\u00C2\u00A0Andes\u00C2\u00A0(modified\u00C2\u00A0after\u00C2\u00A0Benavides\u00E2\u0080\u0090C\u00C3\u00A1ceres,\u00C2\u00A0 1999).\u00C2\u00A0\u00C2\u00A0Cretaceous\u00C2\u00A0marginal\u00C2\u00A0basins\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0Lancones\u00C2\u00A0(LB),\u00C2\u00A0Huarmey\u00C2\u00A0(HB)\u00C2\u00A0and\u00C2\u00A0Ca\u00C3\u00B1ete\u00C2\u00A0(CB)\u00C2\u00A0basins\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0\u00C2\u00A0are\u00C2\u00A0 superimposed.\u00C2\u00A0\u00C2\u00A0Also\u00C2\u00A0shown\u00C2\u00A0are\u00C2\u00A0the\u00C2\u00A0locations\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0prospects\u00C2\u00A0(circles)\u00C2\u00A0(data\u00C2\u00A0from\u00C2\u00A0 Steinm\u00C3\u00BCller\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02000).\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 111\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A04.2.\u00C2\u00A0\u00C2\u00A0A.\u00C2\u00A0Location\u00C2\u00A0map\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0Tambogrande\u00C2\u00A0project;\u00C2\u00A0B.\u00C2\u00A0regional\u00C2\u00A0map\u00C2\u00A0showing\u00C2\u00A0major\u00C2\u00A0 tectonostratigraphic\u00C2\u00A0units\u00C2\u00A0of\u00C2\u00A0coastal\u00C2\u00A0northwestern\u00C2\u00A0Per\u00C3\u00BA.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0locations\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0(TG1,\u00C2\u00A0 TG3,\u00C2\u00A0and\u00C2\u00A0B5)\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Tambogrande\u00C2\u00A0area\u00C2\u00A0are\u00C2\u00A0also\u00C2\u00A0shown\u00C2\u00A0and\u00C2\u00A0field\u00C2\u00A0area\u00C2\u00A0of\u00C2\u00A0this\u00C2\u00A0study\u00C2\u00A0outlined\u00C2\u00A0(see\u00C2\u00A0 Fig.\u00C2\u00A04.3\u00C2\u00A0for\u00C2\u00A0a\u00C2\u00A0detailed\u00C2\u00A0map).\u00C2\u00A0\u00C2\u00A0Modified\u00C2\u00A0after\u00C2\u00A0Jaillard\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1999),\u00C2\u00A0Tegart\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(2000).\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 112\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A04.3\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A0Location\u00C2\u00A0map\u00C2\u00A0and\u00C2\u00A0simplified\u00C2\u00A0cross\u00C2\u00A0sections\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0Peruvian\u00C2\u00A0continental\u00C2\u00A0margin\u00C2\u00A0 based\u00C2\u00A0on\u00C2\u00A0gravity\u00C2\u00A0modeling\u00C2\u00A0and\u00C2\u00A0seismic\u00C2\u00A0data\u00C2\u00A0from\u00C2\u00A0Couch\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1981)\u00C2\u00A0and\u00C2\u00A0Jones\u00C2\u00A0(1981).\u00C2\u00A0 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versus\u00C2\u00A0Zr/TiO2\u00C2\u00A0plot\u00C2\u00A0of\u00C2\u00A0Winchester\u00C2\u00A0and\u00C2\u00A0Floyd\u00C2\u00A0(1977).\u00C2\u00A0\u00C2\u00A0C.\u00C2\u00A0\u00C2\u00A0AFM\u00C2\u00A0plot\u00C2\u00A0(Irvine\u00C2\u00A0and\u00C2\u00A0Baragar,\u00C2\u00A01971).\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 117\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A04.7.\u00C2\u00A0\u00C2\u00A0Bivariate\u00C2\u00A0plots\u00C2\u00A0of\u00C2\u00A0basalt\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo,\u00C2\u00A0Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0and\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0 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Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 124\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A04.14.\u00C2\u00A0\u00C2\u00A0Ta/Yb\u00C2\u00A0versus\u00C2\u00A0Th/Yb\u00C2\u00A0plot\u00C2\u00A0after\u00C2\u00A0Pearce\u00C2\u00A0(1983).\u00C2\u00A0\u00C2\u00A0Only\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0 and\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation\u00C2\u00A0basalt\u00C2\u00A0shown\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0data\u00C2\u00A0limits\u00C2\u00A0for\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0D\u00C2\u00A0=\u00C2\u00A0depleted\u00C2\u00A0 mantle.\u00C2\u00A0\u00C2\u00A0E\u00C2\u00A0=\u00C2\u00A0enriched\u00C2\u00A0mantle.\u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 125\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A04.15.\u00C2\u00A0\u00C2\u00A0Schematic\u00C2\u00A0two\u00E2\u0080\u0090stage\u00C2\u00A0tectonic\u00C2\u00A0model\u00C2\u00A0for\u00C2\u00A0arc\u00C2\u00A0magmatism\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin.\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0model\u00C2\u00A0proposes\u00C2\u00A0a\u00C2\u00A0shift\u00C2\u00A0from\u00C2\u00A0phase\u00C2\u00A01,\u00C2\u00A0extensional\u00C2\u00A0tectonics\u00C2\u00A0with\u00C2\u00A0a\u00C2\u00A0steeply\u00C2\u00A0dipping\u00C2\u00A0 subduction\u00C2\u00A0zone\u00C2\u00A0to\u00C2\u00A0phase\u00C2\u00A02,\u00C2\u00A0waning\u00C2\u00A0extension\u00C2\u00A0and\u00C2\u00A0shallower\u00C2\u00A0subduction.\u00C2\u00A0Depletion\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 mantle\u00E2\u0080\u0090wedge\u00C2\u00A0explains\u00C2\u00A0the\u00C2\u00A0relatively\u00C2\u00A0HFSE\u00E2\u0080\u0090\u00C2\u00A0and\u00C2\u00A0REE\u00E2\u0080\u0090depleted\u00C2\u00A0mafic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0phase\u00C2\u00A0 2.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0thickened\u00C2\u00A0crust\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0waning\u00C2\u00A0extension\u00C2\u00A0forces\u00C2\u00A0more\u00C2\u00A0fractionation\u00C2\u00A0of\u00C2\u00A0mafic\u00C2\u00A0intrusions.\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0partial\u00C2\u00A0melting\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0arc\u00C2\u00A0crust\u00C2\u00A0causes\u00C2\u00A0phase\u00C2\u00A02\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0to\u00C2\u00A0yield\u00C2\u00A0lower\u00C2\u00A0HFSE\u00C2\u00A0 contents.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 126\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A04.\u00C2\u00A016.\u00C2\u00A0\u00C2\u00A0Felsic\u00C2\u00A0volcanic\u00C2\u00A0rock\u00C2\u00A0discrimination\u00C2\u00A0diagrams\u00C2\u00A0(after\u00C2\u00A0Lesher\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01986;\u00C2\u00A0Barrie\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A0 1993;\u00C2\u00A0Lentz,\u00C2\u00A01998;\u00C2\u00A0Hart\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02004).\u00C2\u00A0\u00C2\u00A0A.\u00C2\u00A0\u00C2\u00A0(La/Yb)N\u00C2\u00A0versus\u00C2\u00A0YbN\u00C2\u00A0(Chondrite\u00E2\u0080\u0090normalized\u00C2\u00A0using\u00C2\u00A0values\u00C2\u00A0 from\u00C2\u00A0Sun\u00C2\u00A0and\u00C2\u00A0McDonough\u00C2\u00A0(1989)).\u00C2\u00A0\u00C2\u00A0B.\u00C2\u00A0\u00C2\u00A0Zr/Y\u00C2\u00A0versus\u00C2\u00A0Y.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 127\u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 128\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Table\u00C2\u00A04.1\u00C2\u00A0(Following\u00C2\u00A0page).\u00C2\u00A0\u00C2\u00A0Average\u00C2\u00A0lithogeochemical\u00C2\u00A0values\u00C2\u00A0and\u00C2\u00A02\u00C2\u00A0\u00CF\u0083\u00C2\u00A0errors\u00C2\u00A0for\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0Lancones\u00C2\u00A0basin,\u00C2\u00A0based\u00C2\u00A0on\u00C2\u00A0volcanic\u00C2\u00A0rock\u00C2\u00A0type\u00C2\u00A0and\u00C2\u00A0formation.\u00C2\u00A0\u00C2\u00A0Complete\u00C2\u00A0data\u00C2\u00A0are\u00C2\u00A0listed\u00C2\u00A0in\u00C2\u00A0 Appendix\u00C2\u00A0C.\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 CSLF basalt (n=42) 2\u00CF\u0083 CEEF basalt (n=7) 2\u00CF\u0083 LBF basalt (n=9) 2\u00CF\u0083 CSLF basaltic- andesite (n=10) 2\u00CF\u0083 CEEF basaltic- andesite (n=1) LBF basaltic- andesite (n=10) 2\u00CF\u0083 CSLF post- mineral- ization andesite (n=7) 2\u00CF\u0083 CSLF syn- mineral- ization rhyolite (n=22) 2\u00CF\u0083 SiO2 (wt.%) 49.62 4.67 48.91 3.14 51.43 4.88 58.28 3.29 59.12 61.92 5.63 67.26 5.67 71.68 6.44 TiO2 0.90 0.48 0.74 0.34 0.83 0.44 0.82 3.29 0.97 0.63 0.27 0.63 0.11 0.30 0.15 Al2O3 16.20 2.69 18.67 1.81 16.80 5.10 16.30 0.36 15.32 15.74 3.73 14.47 1.79 13.18 2.44 Fe2O3 9.54 2.61 10.54 1.96 10.59 5.44 6.97 1.90 9.93 6.33 4.82 4.11 1.93 2.99 2.31 MnO 0.16 0.10 0.23 0.29 0.18 0.06 0.13 2.86 0.18 0.13 0.14 0.07 0.05 0.05 0.06 MgO 7.40 4.38 4.74 1.83 3.92 1.46 3.08 0.07 2.08 1.53 1.42 1.62 1.38 1.13 1.73 CaO 8.37 6.96 10.71 6.08 9.76 7.43 4.82 1.75 6.70 5.47 2.79 2.96 3.69 1.59 1.44 Na2O 3.02 2.36 2.60 2.34 3.00 2.20 4.93 3.07 4.54 4.63 2.11 4.85 2.29 5.35 2.84 K2O 0.66 1.25 0.31 0.50 0.39 0.59 1.01 1.74 0.18 0.72 1.28 1.38 2.17 1.03 1.87 P2O5 0.15 0.15 0.06 0.04 0.12 0.11 0.09 0.77 0.15 0.17 0.08 0.17 0.08 0.07 0.06 LOI 3.59 4.83 2.23 2.54 2.99 5.11 2.71 0.22 1.11 2.71 1.97 2.37 2.42 2.00 2.31 TOTAL 99.67 1.38 99.76 1.21 100.05 0.63 99.40 3.55 100.30 100.06 0.55 99.94 0.60 99.44 1.65 Cr (ppm) 227 566 79 94 129 416 61 16 90 86 55 81 66 125 152 Ni 68 121 19 21 24 34 15 50 5 14 14 11 14 6 9 Co 36 19 30 10 33 13 19 17 18 10 7 12 12 4 7 Sc 33 11 40 14 16 19 n/a n/a 15 2 10 12 V 308 154 360 54 434 259 151 7 145 126 121 51 45 15 32 Li 8 9 6 0 n/a 3 127 n/a n/a 2 5 3 4 Cu 89 146 109 156 159 127 71 6 20 61 114 29 27 56 181 Pb 7 7 5 14 6 4 5 140 5 5 0 3 8 2 8 Zn 110 116 83 50 100 60 87 7 100 63 41 52 35 76 116 Rb 16 31 6 10 8 14 2 55 2 22 33 24 40 21 41 Cs 1 1 1 0 1 1 1 15 0 1 2 1 2 1 1 Ba 498 1251 156 157 235 350 758 2 121 520 730 788 1131 642 1739 Sr 225 178 193 78 224 162 255 1177 101 352 240 142 190 99 111 Ga 17.0 4.9 17.4 1.0 18.8 4.8 5 200 22.0 14.6 6.3 16.3 6.2 16.7 4.1 Ta 0.1 0.4 0.0 0.0 n/a 0.4 3.3 <0.5 0.5 0.0 0.2 0.1 0.4 0.3 Nb 2.0 2.3 0.8 0.3 2.0 2.0 4.7 0.2 1.0 3.3 4.4 4.1 1.2 5.4 5.9 Hf 1.6 1.1 1.3 0.4 1.5 1.5 4.0 3.4 1.0 3.1 2.1 4.9 1.5 5.6 2.2 Zr 53 34 30 24 39 49 130.6 1.8 58 109 78 160 32 195 79 Y 17 9 15 8 21 12 28 58 29 23 24 34 13 39 23 Th 2.1 2.9 0.5 0.7 2.3 3.8 7 15 1.0 4.8 4.2 5.2 3.4 7.3 8.2 U 0.7 0.9 0.5 0.0 0.8 0.9 1.8 5.3 0.5 1.4 1.3 2.2 1.2 3.0 2.8 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 129\u00C2\u00A0 \u00C2\u00A0 Table\u00C2\u00A04.1.\u00C2\u00A0Continued\u00C2\u00A0 \u00C2\u00A0CSLF post- mineralization rhyolite dyke (n=3) 2 \u00CF\u0083 LBF dacite- rhyolite (n=17) 2 \u00CF\u0083 SiO2 (wt.%) 71.79 5.13 72.66 4.36 TiO2 0.31 0.17 0.31 0.10 Al2O3 13.17 0.94 13.01 1.37 Fe2O3 3.13 1.26 2.77 1.14 MnO 0.08 0.03 0.07 0.06 MgO 0.96 0.33 0.86 0.80 CaO 1.89 1.43 2.13 1.08 Na2O 4.50 1.04 4.91 1.22 K2O 1.06 0.86 0.84 0.74 P2O5 0.06 0.03 0.07 0.04 LOI 2.67 1.62 2.04 1.46 TOTAL 99.63 0.88 99.74 0.44 Cr (ppm) 36 16 121 65 Ni 0 4 12 7 Co 5 4 4 2 Sc 8 3 n/a V 19 19 23 17 Li 1 4 n/a Cu 10 32 46 57 Pb 0 6 8 4 Zn 83 12 63 42 Rb 25 19 17 17 Cs 1 0 Ba 764 906 518 429 Sr 127 20 120 62 Ga n/a 14.0 3.0 Ta 0.3 0.1 0.5 0.0 Nb 3.7 1.9 2.4 1.9 Hf 5.4 0.9 3.7 1.2 Zr 177 37 117 42 Y 31 7 33 10 Th 8.5 0.6 4.5 3.2 U n/a 2.1 1.5 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 130\u00C2\u00A0 \u00C2\u00A0 Table\u00C2\u00A04.1.\u00C2\u00A0Continued\u00C2\u00A0 CSLF basalt (n=42) 2\u00CF\u0083 CEEF basalt (n=7) 2\u00CF\u0083 LBF basalt (n=9) 2\u00CF\u0083 CSLF basaltic- andesite (n=10) 2\u00CF\u0083 CEEF basaltic- andesite (n=1) LBF basaltic- andesite (n=10) 2\u00CF\u0083 CSLF post- mineral -ization andesite (n=7) 2\u00CF\u0083 CSLF syn- mineral -ization rhyolite (n=22) 2\u00CF\u0083 La (ppm) 6.8 7.0 2.6 3.1 4.2 7.1 15.6 1.7 6.0 14.3 10.0 15.1 12.1 17.0 10.4 Ce 14.8 13.5 5.8 4.4 8.8 14.4 34.2 10.8 14.5 28.8 22.8 32.8 22.6 37.4 19.5 Pr 2.1 1.7 0.9 0.7 1.3 1.9 4.7 22.1 2.2 3.8 3.1 4.5 3.0 5.0 2.3 Nd 9.7 7.1 4.8 3.5 6.6 8.6 20.1 2.8 11.0 15.4 12.2 19.5 9.9 21.5 8.9 Sm 2.7 1.6 1.6 1.0 2.2 2.1 4.9 11.7 3.5 3.8 3.3 5.1 1.8 5.5 2.4 Eu 0.9 0.5 0.6 0.3 0.8 0.5 1.4 2.5 1.1 1.0 0.5 1.4 0.6 1.3 0.6 Gd 2.9 1.5 2.0 1.2 2.6 1.8 4.9 0.8 3.7 4.0 3.5 5.5 1.6 5.9 2.7 Tb 0.5 0.2 0.4 0.2 0.5 0.3 0.8 2.3 0.7 0.7 0.6 0.9 0.4 1.0 0.5 Dy 3.0 1.5 2.5 1.4 3.3 1.9 4.8 0.4 4.6 3.8 3.8 5.8 1.7 6.5 3.7 Ho 0.7 0.3 0.6 0.3 0.8 0.5 1.1 2.4 1.1 0.9 0.9 1.4 0.5 1.5 0.8 Er 2.0 1.0 1.7 1.0 2.2 1.3 3.2 0.5 2.9 2.4 2.5 4.2 1.4 4.6 2.5 Tm 0.3 0.2 0.2 0.1 0.4 0.2 0.5 1.6 0.5 0.4 0.4 0.6 0.2 0.7 0.4 Yb 1.9 0.9 1.7 0.8 2.3 1.2 3.2 0.2 3.2 2.4 2.6 4.0 1.2 4.5 2.3 Lu 0.3 0.1 0.2 0.2 0.4 0.2 0.5 1.4 0.5 0.4 0.4 0.6 0.2 0.7 0.4 \u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 131\u00C2\u00A0 \u00C2\u00A0 Table\u00C2\u00A04.1.\u00C2\u00A0Continued\u00C2\u00A0 CSLF post- mineralization rhyolite dyke (n=3) 2\u00CF\u0083 LBF dacite- rhyolite (n=17) 2\u00CF\u0083 La 18.3 2.7 11.2 4.8 Ce 37.5 6.0 23.8 10.8 Pr 4.8 0.8 3.3 1.4 Nd 19.7 4.1 14.5 5.4 Sm 4.8 1.1 4.0 1.2 Eu 1.2 0.5 0.9 0.3 Gd 4.6 1.1 4.4 1.3 Tb 0.8 0.2 0.8 0.2 Dy 5.2 1.2 5.2 1.6 Ho 1.2 0.3 1.2 0.4 Er 3.9 0.8 3.5 1.1 Tm 0.6 0.1 0.5 0.2 Yb 3.8 0.7 3.6 1.2 Lu 0.6 0.1 0.6 0.2 \u00C2\u00A0 Abbreviations:\u00C2\u00A0CSLF\u00C2\u00A0=\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation;\u00C2\u00A0CEEF\u00C2\u00A0=\u00C2\u00A0Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation;\u00C2\u00A0LBF\u00C2\u00A0=\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation.\u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 132\u00C2\u00A0 \u00C2\u00A0 Table\u00C2\u00A04.2.\u00C2\u00A0\u00C2\u00A0Summary\u00C2\u00A0of\u00C2\u00A0average\u00C2\u00A0selected\u00C2\u00A0trace\u00C2\u00A0element\u00C2\u00A0ratios\u00C2\u00A0for\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0based\u00C2\u00A0on\u00C2\u00A0volcanic\u00C2\u00A0rock\u00C2\u00A0type\u00C2\u00A0and\u00C2\u00A0 formation.\u00C2\u00A0 \u00C2\u00A0 CSLF basalt (n=42) 2\u00CF\u0083 CEEF basalt (n=7) 2\u00CF\u0083 LBF basalt (n=9) 2\u00CF\u0083 CSLF basaltic- andesite (n=10) 2\u00CF\u0083 CEEF basaltic- andesite (n=1) LBF basaltic- andesite (n=10) 2\u00CF\u0083 CSLF post- mineral- ization andesit e (n=7) 2\u00CF\u0083 CSLF syn- mineral -ization rhyolite (n=22) 2\u00CF\u0083 Nb/Y 0.1 0.1 0.0 0.0 0.1 0.1 0.0 0.1 0.2 0.1 0.1 0.1 0.3 Nb/Yb 1.1 1.2 0.4 0.0 0.6 0.6 1.5 0.1 0.3 1.3 1.7 1.0 1.0 1.2 2.5 Zr/Nb 31.0 19.4 57.7 10.8 45.7 23.7 29.2 1.0 58.0 47.8 59.9 39.6 15.6 43.9 33.9 La/Nb 3.8 3.4 4.1 3.8 5.8 3.3 3.5 10.8 6.0 6.0 5.5 3.6 2.4 3.8 4.2 Th/Nb 1.1 1.3 0.4 0.1 1.3 0.7 1.5 2.4 1.9 2.1 1.2 0.6 1.6 1.9 (Th/La)PM 2.3 1.8 1.0 2.0 2.2 1.8 2.5 1.4 0.0 2.7 2.1 3.1 2.4 2.7 1.5 Zr/TiO2 59 31 40 17 47 40 164 5 60 184 124 255 35 674 314 Zr/Y 3.1 1.7 2.0 0.9 1.8 1.1 4.8 65.7 2.0 5.3 4.6 4.9 2.2 5.4 3.6 (La/Yb)N 2.5 2.7 1.0 0.7 1.1 1.4 42.4 2.0 1.3 4.6 3.9 2.6 2.0 2.8 2.7 Eu/Eu* 0.98 0.17 1.07 0.17 1.00 0.23 0.83 2.41 0.93 0.86 0.28 0.78 0.16 0.68 0.23 Nb/Nb* 0.19 0.18 0.26 0.20 0.12 0.01 0.17 0.29 0.14 0.11 0.10 0.16 0.07 0.17 0.12 Zr/Zr* 0.86 0.34 0.78 0.47 0.71 0.24 1.25 0.17 0.74 1.35 0.89 1.42 0.66 1.60 0.65 Hf/Hf* 0.96 0.55 1.07 0.89 0.89 0.28 1.40 0.60 0.46 1.39 0.81 1.60 0.87 1.66 0.65 Ti/Ti* 0.79 0.37 1.03 0.55 0.88 0.48 0.39 0.84 0.63 0.39 0.17 0.29 0.11 0.13 0.09 \u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 133\u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 134\u00C2\u00A0 \u00C2\u00A0 Table\u00C2\u00A04..\u00C2\u00A0Continued\u00C2\u00A0 CSLF post- ore rhyolite dyke (n=3) 2\u00CF\u0083 LBF dacite- rhyolite (n=17) 2\u00CF\u0083 Nb/Y 0.1 0.3 0.1 0.2 Nb/Yb 1.0 2.7 0.7 1.7 Zr/Nb 49.6 17.4 69.3 31.7 La/Nb 5.2 2.1 6.6 3.6 Th/Nb 2.4 1.2 2.2 1.3 (Th/La)PM 3.8 0.5 2.8 1.0 Zr/TiO2 594 246 422 171 Zr/Y 5.7 0.2 3.7 1.2 (La/Yb)N 3.3 0.2 2.3 1.3 Eu/Eu* 0.7 0.1 0.7 0.2 Nb/Nb* 0.1 0.0 0.1 0.1 Zr/Zr* 1.7 0.1 1.3 0.4 Hf/Hf* 1.9 0.2 1.5 0.4 Ti/Ti* 0.2 0.1 0.2 0.1 \u00C2\u00A0\u00C2\u00A0 Notes:\u00C2\u00A0 CSLF,\u00C2\u00A0CEEF,\u00C2\u00A0LBF\u00C2\u00A0as\u00C2\u00A0per\u00C2\u00A0table\u00C2\u00A01.\u00C2\u00A0\u00C2\u00A0 PM\u00C2\u00A0=\u00C2\u00A0primitive\u00C2\u00A0mantle\u00C2\u00A0normalized\u00C2\u00A0\u00C2\u00A0 N\u00C2\u00A0=\u00C2\u00A0chondrite\u00C2\u00A0normalized\u00C2\u00A0 Eu/Eu*\u00C2\u00A0=\u00C2\u00A00.5EuPM\u00C2\u00A0/(GdPM\u00C2\u00A0+\u00C2\u00A0SmPM)\u00C2\u00A0 Nb/Nb*\u00C2\u00A0=\u00C2\u00A00.5*NbPM/(ThPM\u00C2\u00A0+\u00C2\u00A0LaPM)\u00C2\u00A0 Zr/Zr*\u00C2\u00A0=\u00C2\u00A00.5*ZrPM/(GdPM\u00C2\u00A0+\u00C2\u00A0SmPM)\u00C2\u00A0 Hf/Hf*\u00C2\u00A0=\u00C2\u00A00.5*HfPM/(GdPM\u00C2\u00A0+\u00C2\u00A0SmPM)\u00C2\u00A0\u00C2\u00A0 Ti/Ti*\u00C2\u00A0=\u00C2\u00A00.5*TiPM/(GdPM\u00C2\u00A0+\u00C2\u00A0SmPM)\u00C2\u00A0 4.8\u00C2\u00A0 References\u00C2\u00A0 Aguirre\u00C2\u00A0L,\u00C2\u00A0Offler,\u00C2\u00A0R.\u00C2\u00A0\u00C2\u00A01985.\u00C2\u00A0\u00C2\u00A0Burial\u00C2\u00A0metamorphism\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Western\u00C2\u00A0Peruvian\u00C2\u00A0trough:\u00C2\u00A0its\u00C2\u00A0relation\u00C2\u00A0to\u00C2\u00A0 Andean\u00C2\u00A0magmatism\u00C2\u00A0and\u00C2\u00A0tectonics.\u00C2\u00A0\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0W.S.\u00C2\u00A0Pitcher,\u00C2\u00A0M.P.\u00C2\u00A0Atherton,\u00C2\u00A0E.J.\u00C2\u00A0Cobbing,\u00C2\u00A0and\u00C2\u00A0 R.D.\u00C2\u00A0Beckinsdale.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0Magmatism\u00C2\u00A0at\u00C2\u00A0a\u00C2\u00A0plate\u00C2\u00A0edge:\u00C2\u00A0the\u00C2\u00A0Peruvian\u00C2\u00A0Andes,\u00C2\u00A0Blackie,\u00C2\u00A0Glasgow,\u00C2\u00A0pp.\u00C2\u00A0 59\u00E2\u0080\u009371.\u00C2\u00A0 \u00C2\u00A0 Arculus,\u00C2\u00A0R.J.,\u00C2\u00A0Lapierre,\u00C2\u00A0H.,\u00C2\u00A0and\u00C2\u00A0Jaillard,\u00C2\u00A0E.\u00C2\u00A0\u00C2\u00A01999.\u00C2\u00A0\u00C2\u00A0Geochemical\u00C2\u00A0window\u00C2\u00A0into\u00C2\u00A0subduction\u00C2\u00A0and\u00C2\u00A0 accretion\u00C2\u00A0processes;\u00C2\u00A0Raspas\u00C2\u00A0metamorphic\u00C2\u00A0complex,\u00C2\u00A0Ecuador.\u00C2\u00A0\u00C2\u00A0Geology,\u00C2\u00A027:\u00C2\u00A0547\u00E2\u0080\u0090550.\u00C2\u00A0 \u00C2\u00A0 Aspden,\u00C2\u00A0J.A.,\u00C2\u00A0Bonilla,\u00C2\u00A0W.\u00C2\u00A0and\u00C2\u00A0Duque,\u00C2\u00A0P.,\u00C2\u00A01995.\u00C2\u00A0The\u00C2\u00A0El\u00C2\u00A0Oro\u00C2\u00A0metamorphic\u00C2\u00A0complex,\u00C2\u00A0Ecuador:\u00C2\u00A0 geology\u00C2\u00A0and\u00C2\u00A0economic\u00C2\u00A0mineral\u00C2\u00A0deposits.\u00C2\u00A0\u00C2\u00A0British\u00C2\u00A0Geological\u00C2\u00A0Survey,\u00C2\u00A0Overseas\u00C2\u00A0Geology\u00C2\u00A0and\u00C2\u00A0 Mineral\u00C2\u00A0Resources\u00C2\u00A0Series\u00C2\u00A067,\u00C2\u00A063\u00C2\u00A0p.\u00C2\u00A0 \u00C2\u00A0 Atherton,\u00C2\u00A0M.P.,\u00C2\u00A01990.\u00C2\u00A0The\u00C2\u00A0Coastal\u00C2\u00A0Batholith\u00C2\u00A0of\u00C2\u00A0Peru:\u00C2\u00A0the\u00C2\u00A0product\u00C2\u00A0of\u00C2\u00A0rapid\u00C2\u00A0recycling\u00C2\u00A0of\u00C2\u00A0new\u00C2\u00A0crust\u00C2\u00A0 formed\u00C2\u00A0within\u00C2\u00A0rifted\u00C2\u00A0continental\u00C2\u00A0margin.\u00C2\u00A0Geological\u00C2\u00A0Journal,\u00C2\u00A025:\u00C2\u00A0335\u00E2\u0080\u0093349.\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Atherton,\u00C2\u00A0M.P.,\u00C2\u00A0Pitcher,\u00C2\u00A0W.S.,\u00C2\u00A0Warden,\u00C2\u00A0V.\u00C2\u00A0\u00C2\u00A01983.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0Mesozoic\u00C2\u00A0marginal\u00C2\u00A0basin\u00C2\u00A0of\u00C2\u00A0central\u00C2\u00A0Per\u00C3\u00BA.\u00C2\u00A0\u00C2\u00A0 Nature,\u00C2\u00A0350:\u00C2\u00A0303\u00E2\u0080\u0090306.\u00C2\u00A0 \u00C2\u00A0 Bailes,\u00C2\u00A0A.H.\u00C2\u00A0and\u00C2\u00A0Galley,\u00C2\u00A0A.G.\u00C2\u00A01999.\u00C2\u00A0\u00C2\u00A0Evolution\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Paleoproterozoic\u00C2\u00A0Snow\u00C2\u00A0Lake\u00C2\u00A0arc\u00C2\u00A0assemblage\u00C2\u00A0 and\u00C2\u00A0geodynamic\u00C2\u00A0setting\u00C2\u00A0for\u00C2\u00A0associated\u00C2\u00A0volcanic\u00E2\u0080\u0090hosted\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits,\u00C2\u00A0Flin\u00C2\u00A0Flon\u00C2\u00A0 belt,\u00C2\u00A0Manitoba,\u00C2\u00A0Canada.\u00C2\u00A0Canadian\u00C2\u00A0Journal\u00C2\u00A0of\u00C2\u00A0Earth\u00C2\u00A0Sciences,\u00C2\u00A036:\u00C2\u00A01789\u00E2\u0080\u00901805.\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Barker,\u00C2\u00A0D.\u00C2\u00A0H.\u00C2\u00A0N.,\u00C2\u00A0and\u00C2\u00A0Austin,\u00C2\u00A0Jr.\u00C2\u00A0J.\u00C2\u00A0A.\u00C2\u00A0\u00C2\u00A01998.\u00C2\u00A0\u00C2\u00A0Rift\u00C2\u00A0propagation,\u00C2\u00A0detachment\u00C2\u00A0faulting,\u00C2\u00A0and\u00C2\u00A0 associated\u00C2\u00A0magmatism\u00C2\u00A0in\u00C2\u00A0Bransfield\u00C2\u00A0Strait,\u00C2\u00A0Antarctic\u00C2\u00A0Peninsula,\u00C2\u00A0Journal\u00C2\u00A0of\u00C2\u00A0Geophysical\u00C2\u00A0 Research,\u00C2\u00A0\u00C2\u00A0103(B10):\u00C2\u00A024,017\u00E2\u0080\u009024,043.\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Barrag\u00C3\u00A1n,\u00C2\u00A0R.,\u00C2\u00A0Babya,\u00C2\u00A0P.,\u00C2\u00A0and\u00C2\u00A0Duncan,\u00C2\u00A0R.\u00C2\u00A0\u00C2\u00A02005.\u00C2\u00A0\u00C2\u00A0Cretaceous\u00C2\u00A0alkaline\u00C2\u00A0intra\u00E2\u0080\u0090plate\u00C2\u00A0magmatism\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0 Ecuadorian\u00C2\u00A0Oriente\u00C2\u00A0Basin:\u00C2\u00A0Geochemical,\u00C2\u00A0geochronological\u00C2\u00A0and\u00C2\u00A0tectonic\u00C2\u00A0evidence.\u00C2\u00A0\u00C2\u00A0Earth\u00C2\u00A0and\u00C2\u00A0 Planetary\u00C2\u00A0Science\u00C2\u00A0Letters,\u00C2\u00A0236:\u00C2\u00A0670\u00E2\u0080\u0090690.\u00C2\u00A0 \u00C2\u00A0 Barrett,\u00C2\u00A0T.J.\u00C2\u00A0and\u00C2\u00A0MacLean,\u00C2\u00A0W.H.,\u00C2\u00A01999.\u00C2\u00A0\u00C2\u00A0Volcanic\u00C2\u00A0sequences,\u00C2\u00A0lithogeochemistry,\u00C2\u00A0and\u00C2\u00A0 hydrothermal\u00C2\u00A0alteration\u00C2\u00A0in\u00C2\u00A0some\u00C2\u00A0bimodal\u00C2\u00A0volcanic\u00E2\u0080\u0090associated\u00C2\u00A0massive\u00C2\u00A0sulfide\u00C2\u00A0systems.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0 Volcanic\u00E2\u0080\u0090associated\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits:\u00C2\u00A0processes\u00C2\u00A0and\u00C2\u00A0examples\u00C2\u00A0in\u00C2\u00A0modern\u00C2\u00A0and\u00C2\u00A0 ancient\u00C2\u00A0settings.\u00C2\u00A0\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0C.T.\u00C2\u00A0Barrie\u00C2\u00A0and\u00C2\u00A0M.D.\u00C2\u00A0Hannington.\u00C2\u00A0\u00C2\u00A0Reviews\u00C2\u00A0in\u00C2\u00A0Economic\u00C2\u00A0Geology,\u00C2\u00A0 Volume\u00C2\u00A08,\u00C2\u00A0p.\u00C2\u00A0101\u00E2\u0080\u0090131.\u00C2\u00A0 \u00C2\u00A0 Barrie,\u00C2\u00A0C.T.,\u00C2\u00A0Ludden,\u00C2\u00A0J.N.,\u00C2\u00A0Green,\u00C2\u00A0T.H.\u00C2\u00A0\u00C2\u00A01993.\u00C2\u00A0Geochemistry\u00C2\u00A0of\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0Cu\u00E2\u0080\u0090 Zn\u00C2\u00A0and\u00C2\u00A0Ni\u00E2\u0080\u0090Cu\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Abitibi\u00C2\u00A0Subprovince.\u00C2\u00A0\u00C2\u00A0Economic,\u00C2\u00A088:\u00C2\u00A01341\u00E2\u0080\u00901358.\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Barrie,\u00C2\u00A0C.T.\u00C2\u00A0and\u00C2\u00A0Hannington,\u00C2\u00A0M.D.\u00C2\u00A0\u00C2\u00A01999.\u00C2\u00A0\u00C2\u00A0Classification\u00C2\u00A0of\u00C2\u00A0volcanic\u00E2\u0080\u0090associated\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0 deposits\u00C2\u00A0based\u00C2\u00A0on\u00C2\u00A0host\u00E2\u0080\u0090rock\u00C2\u00A0composition.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0Volcanic\u00E2\u0080\u0090associated\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits:\u00C2\u00A0 processes\u00C2\u00A0and\u00C2\u00A0examples\u00C2\u00A0in\u00C2\u00A0modern\u00C2\u00A0and\u00C2\u00A0ancient\u00C2\u00A0settings.\u00C2\u00A0\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0C.T.\u00C2\u00A0Barrie\u00C2\u00A0and\u00C2\u00A0M.D.\u00C2\u00A0 Hannington.\u00C2\u00A0\u00C2\u00A0Reviews\u00C2\u00A0in\u00C2\u00A0Economic\u00C2\u00A0Geology,\u00C2\u00A08:\u00C2\u00A01\u00E2\u0080\u009011.\u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Barrie,\u00C2\u00A0C.T.,\u00C2\u00A0Cathles,\u00C2\u00A0L.M.,\u00C2\u00A0Erendi,\u00C2\u00A0A.\u00C2\u00A0\u00C2\u00A01999.\u00C2\u00A0\u00C2\u00A0Finite\u00C2\u00A0element\u00C2\u00A0heat\u00C2\u00A0and\u00C2\u00A0fluid\u00E2\u0080\u0090flow\u00C2\u00A0computer\u00C2\u00A0 simulations\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0deep\u00C2\u00A0ultramafic\u00C2\u00A0sill\u00C2\u00A0model\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0giant\u00C2\u00A0Kidd\u00C2\u00A0Creek\u00C2\u00A0volcanic\u00E2\u0080\u0090associated\u00C2\u00A0 massive\u00C2\u00A0sulphide\u00C2\u00A0deposit,\u00C2\u00A0Abitibi\u00C2\u00A0Subprovince,\u00C2\u00A0Canada.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0The\u00C2\u00A0Giant\u00C2\u00A0Kidd\u00C2\u00A0Creek\u00C2\u00A0 Volcanogenic\u00C2\u00A0Massive\u00C2\u00A0Sulphide\u00C2\u00A0Deposit,\u00C2\u00A0Western\u00C2\u00A0Abitibi\u00C2\u00A0Subprovince.\u00C2\u00A0\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0M.D.\u00C2\u00A0 Hannington\u00C2\u00A0and\u00C2\u00A0C.T.\u00C2\u00A0Barrie.\u00C2\u00A0\u00C2\u00A0Economic\u00C2\u00A0Geology\u00C2\u00A0Monograph\u00C2\u00A010,\u00C2\u00A0p.529\u00E2\u0080\u0090540.\u00C2\u00A0 \u00C2\u00A0 Beard,\u00C2\u00A0J.S.\u00C2\u00A0and\u00C2\u00A0Lofgren,\u00C2\u00A0G.\u00C2\u00A0E.\u00C2\u00A0\u00C2\u00A01991.\u00C2\u00A0\u00C2\u00A0Dehydration\u00C2\u00A0melting\u00C2\u00A0and\u00C2\u00A0water\u00E2\u0080\u0090saturated\u00C2\u00A0melting\u00C2\u00A0of\u00C2\u00A0 basaltic\u00C2\u00A0and\u00C2\u00A0andesitic\u00C2\u00A0greenstones\u00C2\u00A0and\u00C2\u00A0amphibolites\u00C2\u00A0at\u00C2\u00A01,\u00C2\u00A03\u00C2\u00A0and\u00C2\u00A06.9\u00C2\u00A0kb.\u00C2\u00A0\u00C2\u00A0Journal\u00C2\u00A0of\u00C2\u00A0 Petrology,\u00C2\u00A032:\u00C2\u00A0365\u00E2\u0080\u0090401.\u00C2\u00A0 \u00C2\u00A0 Benavides\u00E2\u0080\u0090C\u00C3\u00A1ceres,\u00C2\u00A0V.\u00C2\u00A0\u00C2\u00A01999.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0Orogenic\u00C2\u00A0evolution\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Peruvian\u00C2\u00A0Andes:\u00C2\u00A0the\u00C2\u00A0Andean\u00C2\u00A0cycle.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0 Geology\u00C2\u00A0and\u00C2\u00A0ore\u00C2\u00A0deposits\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0central\u00C2\u00A0Andes.\u00C2\u00A0\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0B.J.\u00C2\u00A0Skinner.\u00C2\u00A0\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0Economic\u00C2\u00A0 Geologists,\u00C2\u00A0Special\u00C2\u00A0Publication\u00C2\u00A0Number\u00C2\u00A07,\u00C2\u00A0pp.\u00C2\u00A061\u00E2\u0080\u0090107.\u00C2\u00A0 \u00C2\u00A0 Bosch,\u00C2\u00A0D.,\u00C2\u00A0Gabriele,\u00C2\u00A0P.,\u00C2\u00A0Lapierre,\u00C2\u00A0H.,\u00C2\u00A0Malfere,\u00C2\u00A0J.,\u00C2\u00A0and\u00C2\u00A0Jaillard,\u00C2\u00A0E.\u00C2\u00A0\u00C2\u00A02002.\u00C2\u00A0\u00C2\u00A0Geodynamic\u00C2\u00A0significance\u00C2\u00A0 of\u00C2\u00A0the\u00C2\u00A0Raspas\u00C2\u00A0metamorphic\u00C2\u00A0complex\u00C2\u00A0(SW\u00C2\u00A0Ecuador);\u00C2\u00A0geochemical\u00C2\u00A0and\u00C2\u00A0isotopic\u00C2\u00A0constraints.\u00C2\u00A0\u00C2\u00A0 Tectonophysics,\u00C2\u00A0345:\u00C2\u00A083\u00E2\u0080\u0090102.\u00C2\u00A0 \u00C2\u00A0 Campbell,\u00C2\u00A0I.H.,\u00C2\u00A0Coad,\u00C2\u00A0P.,\u00C2\u00A0Franklin,\u00C2\u00A0J.M.,\u00C2\u00A0Gorton,\u00C2\u00A0M.P.,\u00C2\u00A0Scott,\u00C2\u00A0S.D.,\u00C2\u00A0Sowa,\u00C2\u00A0J.,\u00C2\u00A0and\u00C2\u00A0Thurston,\u00C2\u00A0P.C.\u00C2\u00A0\u00C2\u00A0 1982.\u00C2\u00A0\u00C2\u00A0Rare\u00C2\u00A0earth\u00C2\u00A0elements\u00C2\u00A0in\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0Cu\u00E2\u0080\u0090Zn\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0 mineralization;\u00C2\u00A0a\u00C2\u00A0preliminary\u00C2\u00A0report.\u00C2\u00A0Canadian\u00C2\u00A0Journal\u00C2\u00A0of\u00C2\u00A0Earth\u00C2\u00A0Sciences,\u00C2\u00A019:\u00C2\u00A0619\u00E2\u0080\u0090623.\u00C2\u00A0 \u00C2\u00A0 Ch\u00C3\u00A1vez,\u00C2\u00A0A.,\u00C2\u00A0and\u00C2\u00A0Nu\u00C3\u00B1ez\u00C2\u00A0del\u00C2\u00A0Prado,\u00C2\u00A0S.H.\u00C2\u00A0\u00C2\u00A01991.\u00C2\u00A0\u00C2\u00A0Evoluci\u00C3\u00B3n\u00C2\u00A0vertical\u00C2\u00A0de\u00C2\u00A0facies\u00C2\u00A0de\u00C2\u00A0la\u00C2\u00A0serie\u00C2\u00A0turbiditica\u00C2\u00A0 Cretacea\u00C2\u00A0(Grupo\u00C2\u00A0Copa\u00C2\u00A0Sombrero)\u00C2\u00A0en\u00C2\u00A0el\u00C2\u00A0perf\u00C3\u00ADl\u00C2\u00A0tipo\u00C2\u00A0Huasimal\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A0Encuentros\u00C2\u00A0(Cuenca\u00C2\u00A0Lancones\u00C2\u00A0 en\u00C2\u00A0el\u00C2\u00A0Noreste\u00C2\u00A0del\u00C2\u00A0Per\u00C3\u00BA):\u00C2\u00A0Boletin\u00C2\u00A0de\u00C2\u00A0la\u00C2\u00A0Sociedad\u00C2\u00A0Geol\u00C3\u00B3gica\u00C2\u00A0del\u00C2\u00A0Per\u00C3\u00BA,\u00C2\u00A082:\u00C2\u00A05\u00E2\u0080\u009021.\u00C2\u00A0 \u00C2\u00A0 Cobbing,\u00C2\u00A0E.J.,\u00C2\u00A0Pitcher,\u00C2\u00A0W.S.,\u00C2\u00A0Wilson,\u00C2\u00A0J.J.,\u00C2\u00A0Baldock,\u00C2\u00A0J.W.,\u00C2\u00A0Taylor,\u00C2\u00A0W.P.,\u00C2\u00A0McCourt,\u00C2\u00A0W.,\u00C2\u00A0and\u00C2\u00A0Snelling,\u00C2\u00A0 N.J.\u00C2\u00A0\u00C2\u00A01981.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0geology\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Western\u00C2\u00A0Cordillera\u00C2\u00A0of\u00C2\u00A0Northern\u00C2\u00A0Per\u00C3\u00BA.\u00C2\u00A0\u00C2\u00A0Institute\u00C2\u00A0of\u00C2\u00A0Geological\u00C2\u00A0 Sciences,\u00C2\u00A0Natural\u00C2\u00A0Environment\u00C2\u00A0Research\u00C2\u00A0Council,\u00C2\u00A0Overseas\u00C2\u00A0Memoir\u00C2\u00A05,\u00C2\u00A0143\u00C2\u00A0p.\u00C2\u00A0 \u00C2\u00A0 Couch,\u00C2\u00A0R.,\u00C2\u00A0Whitsett,\u00C2\u00A0R.,\u00C2\u00A0Huehn,\u00C2\u00A0B.\u00C2\u00A0and\u00C2\u00A0Briceno\u00E2\u0080\u0090Guarupe,\u00C2\u00A0L.\u00C2\u00A0\u00C2\u00A01981.\u00C2\u00A0\u00C2\u00A0Structures\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0continental\u00C2\u00A0 margin\u00C2\u00A0of\u00C2\u00A0Peru\u00C2\u00A0and\u00C2\u00A0Chile.\u00C2\u00A0\u00C2\u00A0Memoirs\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Geological\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0America,\u00C2\u00A0154:\u00C2\u00A0703\u00E2\u0080\u0093726.\u00C2\u00A0 \u00C2\u00A0 Dalziel,\u00C2\u00A0I.W.D.\u00C2\u00A0\u00C2\u00A01981.\u00C2\u00A0\u00C2\u00A0Back\u00E2\u0080\u0090arc\u00C2\u00A0extension\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0southern\u00C2\u00A0Andes:\u00C2\u00A0A\u00C2\u00A0review\u00C2\u00A0and\u00C2\u00A0critical\u00C2\u00A0 reappraisal.\u00C2\u00A0\u00C2\u00A0Philosophical\u00C2\u00A0Transactions\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Royal\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0London,\u00C2\u00A0Series\u00C2\u00A0A,\u00C2\u00A0300:\u00C2\u00A0319\u00E2\u0080\u0090 335.\u00C2\u00A0 \u00C2\u00A0 Ewart,\u00C2\u00A0A.\u00C2\u00A0and\u00C2\u00A0Hawkesworth,\u00C2\u00A0C.J.\u00C2\u00A0\u00C2\u00A01987.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0Pleistocene\u00E2\u0080\u0090recent\u00C2\u00A0Tonga\u00E2\u0080\u0090Kermadec\u00C2\u00A0arc\u00C2\u00A0lavas;\u00C2\u00A0 interpretation\u00C2\u00A0of\u00C2\u00A0new\u00C2\u00A0isotopic\u00C2\u00A0and\u00C2\u00A0rare\u00C2\u00A0earth\u00C2\u00A0data\u00C2\u00A0in\u00C2\u00A0terms\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0depleted\u00C2\u00A0mantle\u00C2\u00A0source\u00C2\u00A0 model.\u00C2\u00A0\u00C2\u00A0Journal\u00C2\u00A0of\u00C2\u00A0Petrology,\u00C2\u00A028:\u00C2\u00A0495\u00E2\u0080\u0090530.\u00C2\u00A0 \u00C2\u00A0 Franklin,\u00C2\u00A0J.M.,\u00C2\u00A0Gibson,\u00C2\u00A0H.L.,\u00C2\u00A0Jonasson,\u00C2\u00A0I.R.,\u00C2\u00A0and\u00C2\u00A0Galley,\u00C2\u00A0A.G.\u00C2\u00A0\u00C2\u00A02005.\u00C2\u00A0\u00C2\u00A0Volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulfide\u00C2\u00A0 deposits.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0Economic\u00C2\u00A0Geology;\u00C2\u00A0one\u00C2\u00A0hundredth\u00C2\u00A0anniversary\u00C2\u00A0volume,\u00C2\u00A01905\u00E2\u0080\u00902005.\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0 J.W.\u00C2\u00A0Hedenquist,\u00C2\u00A0J.F.H.\u00C2\u00A0Thompson,\u00C2\u00A0R.J.\u00C2\u00A0Goldfarb\u00C2\u00A0and\u00C2\u00A0J.P.\u00C2\u00A0Richards.\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0Economic\u00C2\u00A0 Geologists,\u00C2\u00A0pp.\u00C2\u00A0523\u00E2\u0080\u0090560.\u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Gibson,\u00C2\u00A0H.L.\u00C2\u00A0and\u00C2\u00A0Watkinson,\u00C2\u00A0D.H.\u00C2\u00A0\u00C2\u00A01990.\u00C2\u00A0\u00C2\u00A0Volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 Noranda\u00C2\u00A0cauldron\u00C2\u00A0and\u00C2\u00A0shield\u00C2\u00A0volcano.\u00C2\u00A0CIM\u00C2\u00A0Special\u00C2\u00A0Volume\u00C2\u00A043,\u00C2\u00A0pp.\u00C2\u00A0119\u00E2\u0080\u0090132.\u00C2\u00A0 \u00C2\u00A0 Gill,\u00C2\u00A0J.E.\u00C2\u00A0\u00C2\u00A01981.\u00C2\u00A0\u00C2\u00A0Orogenic\u00C2\u00A0Andesites\u00C2\u00A0and\u00C2\u00A0Plate\u00C2\u00A0Tectonics.\u00C2\u00A0\u00C2\u00A0Springer\u00C2\u00A0Verlag.\u00C2\u00A0390\u00C2\u00A0p.\u00C2\u00A0 \u00C2\u00A0 Green,\u00C2\u00A0T.H.\u00C2\u00A0\u00C2\u00A01980.\u00C2\u00A0\u00C2\u00A0Island\u00C2\u00A0arc\u00C2\u00A0and\u00C2\u00A0continent\u00E2\u0080\u0090building\u00C2\u00A0magmatism;\u00C2\u00A0a\u00C2\u00A0review\u00C2\u00A0of\u00C2\u00A0petrogenic\u00C2\u00A0models\u00C2\u00A0 based\u00C2\u00A0on\u00C2\u00A0experimental\u00C2\u00A0petrology\u00C2\u00A0and\u00C2\u00A0geochemistry.\u00C2\u00A0\u00C2\u00A0Tectonophysics,\u00C2\u00A063:\u00C2\u00A0367\u00E2\u0080\u0090385.\u00C2\u00A0 \u00C2\u00A0 Hajash,\u00C2\u00A0A.\u00C2\u00A0and\u00C2\u00A0Chandler,\u00C2\u00A0G.W.\u00C2\u00A01981.\u00C2\u00A0\u00C2\u00A0An\u00C2\u00A0experimental\u00C2\u00A0investigation\u00C2\u00A0of\u00C2\u00A0high\u00E2\u0080\u0090temperature\u00C2\u00A0 interactions\u00C2\u00A0between\u00C2\u00A0seawater\u00C2\u00A0and\u00C2\u00A0rhyolite,\u00C2\u00A0andesite,\u00C2\u00A0basalt\u00C2\u00A0and\u00C2\u00A0peridotite.\u00C2\u00A0Contributions\u00C2\u00A0 to\u00C2\u00A0Mineralogy\u00C2\u00A0and\u00C2\u00A0Petrology,\u00C2\u00A078:\u00C2\u00A0240\u00E2\u0080\u0090254.\u00C2\u00A0 \u00C2\u00A0 Hannington,\u00C2\u00A0M.D.,\u00C2\u00A0and\u00C2\u00A0Barrie,\u00C2\u00A0C.T.\u00C2\u00A0\u00C2\u00A01999.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0giant\u00C2\u00A0Kidd\u00C2\u00A0Creek\u00C2\u00A0volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulfide\u00C2\u00A0 deposit,\u00C2\u00A0western\u00C2\u00A0Abitibi\u00C2\u00A0subprovince,\u00C2\u00A0Canada.\u00C2\u00A0\u00C2\u00A0Economic\u00C2\u00A0Geology\u00C2\u00A0Monograph\u00C2\u00A010,\u00C2\u00A0672\u00C2\u00A0p.\u00C2\u00A0 \u00C2\u00A0 Hanson,\u00C2\u00A0R.E.\u00C2\u00A0and\u00C2\u00A0Wilson,\u00C2\u00A0T.J.\u00C2\u00A0\u00C2\u00A01991.\u00C2\u00A0\u00C2\u00A0Submarine\u00C2\u00A0rhyolitic\u00C2\u00A0volcanism\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0Jurassic\u00C2\u00A0proto\u00E2\u0080\u0090marginal\u00C2\u00A0 basin;\u00C2\u00A0southern\u00C2\u00A0Andes,\u00C2\u00A0Chile\u00C2\u00A0and\u00C2\u00A0Argentina.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0Andean\u00C2\u00A0magmatism\u00C2\u00A0and\u00C2\u00A0its\u00C2\u00A0tectonic\u00C2\u00A0setting.\u00C2\u00A0\u00C2\u00A0 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basalts\u00C2\u00A0and\u00C2\u00A0continental\u00C2\u00A0tholeiites\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0Nb\u00E2\u0088\u0092Zr\u00E2\u0088\u0092Y\u00C2\u00A0diagram.\u00C2\u00A0\u00C2\u00A0Chemical\u00C2\u00A0Geology,\u00C2\u00A056:\u00C2\u00A0207\u00E2\u0080\u0090 218\u00C2\u00A0 \u00C2\u00A0 Mitouard,\u00C2\u00A0P.,\u00C2\u00A0Kissel,\u00C2\u00A0C.,\u00C2\u00A0and\u00C2\u00A0Laj,\u00C2\u00A0C.\u00C2\u00A0\u00C2\u00A01990.\u00C2\u00A0\u00C2\u00A0Post\u00E2\u0080\u0090Oligocene\u00C2\u00A0rotations\u00C2\u00A0in\u00C2\u00A0southern\u00C2\u00A0Ecuador\u00C2\u00A0and\u00C2\u00A0 northern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0formation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Huancabamba\u00C2\u00A0deflection\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Andean\u00C2\u00A0Cordillera.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 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Decennial\u00C2\u00A0International\u00C2\u00A0Conference\u00C2\u00A0on\u00C2\u00A0Mineral\u00C2\u00A0Exploration.\u00C2\u00A0\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0B.\u00C2\u00A0Milkereit.\u00C2\u00A0\u00C2\u00A0 Exploration\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0New\u00C2\u00A0Millennium,\u00C2\u00A05th\u00C2\u00A0Decennial\u00C2\u00A0International\u00C2\u00A0Conference\u00C2\u00A0on\u00C2\u00A0Mineral\u00C2\u00A0 Exploration,\u00C2\u00A0Toronto,\u00C2\u00A0Canada,\u00C2\u00A0Sept\u00C2\u00A09\u00C2\u00A0to\u00C2\u00A012,\u00C2\u00A02007,\u00C2\u00A0pp.\u00C2\u00A0223\u00E2\u0080\u0090246.\u00C2\u00A0 \u00C2\u00A0 Piercey,\u00C2\u00A0S.J.,\u00C2\u00A0Paradis,\u00C2\u00A0S.,\u00C2\u00A0Murphy,\u00C2\u00A0D.C.,\u00C2\u00A0and\u00C2\u00A0Mortensen,\u00C2\u00A0J.K.\u00C2\u00A0\u00C2\u00A02001.\u00C2\u00A0\u00C2\u00A0Geochemistry\u00C2\u00A0and\u00C2\u00A0 paleotectonic\u00C2\u00A0setting\u00C2\u00A0of\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Finlayson\u00C2\u00A0Lake\u00C2\u00A0volcanic\u00E2\u0080\u0090hosted\u00C2\u00A0massive\u00C2\u00A0 sulfide\u00C2\u00A0district,\u00C2\u00A0Yukon,\u00C2\u00A0Canada.\u00C2\u00A0\u00C2\u00A0Economic\u00C2\u00A0Geology,\u00C2\u00A096:\u00C2\u00A01877\u00E2\u0080\u00901905.\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Pitcher,\u00C2\u00A0W.S.\u00C2\u00A0\u00C2\u00A01983.\u00C2\u00A0\u00C2\u00A0Granite\u00C2\u00A0type\u00C2\u00A0and\u00C2\u00A0tectonic\u00C2\u00A0environment.\u00C2\u00A0In\u00C2\u00A0Mountain\u00C2\u00A0Building\u00C2\u00A0Processes.\u00C2\u00A0\u00C2\u00A0 Edited\u00C2\u00A0by\u00C2\u00A0K.\u00C2\u00A0Hsu.\u00C2\u00A0\u00C2\u00A0Academic\u00C2\u00A0Press,\u00C2\u00A0London,\u00C2\u00A0pp.\u00C2\u00A019\u00E2\u0080\u009340.\u00C2\u00A0 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Planetary\u00C2\u00A0Science\u00C2\u00A0Letters,\u00C2\u00A059:\u00C2\u00A0101\u00E2\u0080\u0090118.\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Sinton,\u00C2\u00A0J.M.,\u00C2\u00A0\u00C2\u00A0Ford,\u00C2\u00A0L.L.,\u00C2\u00A0Chappell,\u00C2\u00A0B.,\u00C2\u00A0and\u00C2\u00A0McCulloch,\u00C2\u00A0M.T.\u00C2\u00A0\u00C2\u00A02003.\u00C2\u00A0\u00C2\u00A0Magma\u00C2\u00A0genesis\u00C2\u00A0and\u00C2\u00A0mantle\u00C2\u00A0 heterogeneity\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Manus\u00C2\u00A0back\u00E2\u0080\u0090arc\u00C2\u00A0basin,\u00C2\u00A0Papua\u00C2\u00A0New\u00C2\u00A0Guinea.\u00C2\u00A0\u00C2\u00A0Journal\u00C2\u00A0of\u00C2\u00A0Petrology,\u00C2\u00A044:\u00C2\u00A0 159\u00E2\u0080\u0090195.\u00C2\u00A0 \u00C2\u00A0 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America,\u00C2\u00A0Memoir\u00C2\u00A0191,\u00C2\u00A0pp.\u00C2\u00A0337\u00E2\u0080\u0090365.\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Swinden,\u00C2\u00A0H.S.\u00C2\u00A0\u00C2\u00A01991.\u00C2\u00A0\u00C2\u00A0Paleotectonic\u00C2\u00A0settings\u00C2\u00A0of\u00C2\u00A0volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0 Dunnage\u00C2\u00A0Zone,\u00C2\u00A0Newfoundland\u00C2\u00A0Appalachians:\u00C2\u00A0Canadian\u00C2\u00A0Institute\u00C2\u00A0of\u00C2\u00A0Mining\u00C2\u00A0and\u00C2\u00A0Metallurgy\u00C2\u00A0 Bulletin,\u00C2\u00A083:\u00C2\u00A059\u00E2\u0080\u009369.\u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A04\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 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Science\u00C2\u00A0Letters,\u00C2\u00A0210:\u00C2\u00A0481\u00E2\u0080\u0090497.\u00C2\u00A0 \u00C2\u00A0 Tegart,\u00C2\u00A0P.,\u00C2\u00A0Allen,\u00C2\u00A0G.,\u00C2\u00A0and\u00C2\u00A0Carstensen,\u00C2\u00A0A.,\u00C2\u00A02000,\u00C2\u00A0Regional\u00C2\u00A0setting,\u00C2\u00A0stratigraphy,\u00C2\u00A0alteration\u00C2\u00A0and\u00C2\u00A0 mineralization\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Tambo\u00C2\u00A0Grande\u00C2\u00A0VMS\u00C2\u00A0district,\u00C2\u00A0Piura\u00C2\u00A0Department,\u00C2\u00A0Northern\u00C2\u00A0Per\u00C3\u00BA.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0 VMS\u00C2\u00A0deposits\u00C2\u00A0of\u00C2\u00A0Latin\u00C2\u00A0America.\u00C2\u00A0\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0R.\u00C2\u00A0Sherlock,\u00C2\u00A0and\u00C2\u00A0M.A.V.\u00C2\u00A0Logan.\u00C2\u00A0\u00C2\u00A0Geological\u00C2\u00A0 Association\u00C2\u00A0of\u00C2\u00A0Canada,\u00C2\u00A0Mineral\u00C2\u00A0Deposits\u00C2\u00A0Division,\u00C2\u00A0Special\u00C2\u00A0Paper\u00C2\u00A0No.\u00C2\u00A02,\u00C2\u00A0pp.\u00C2\u00A0375\u00E2\u0080\u0090405.\u00C2\u00A0 \u00C2\u00A0 Vergara,\u00C2\u00A0M.,\u00C2\u00A0Beatriz,\u00C2\u00A0L.,\u00C2\u00A0Nystr\u00C3\u00B6m,\u00C2\u00A0J.O.,\u00C2\u00A0and\u00C2\u00A0Cancino,\u00C2\u00A0A.\u00C2\u00A0\u00C2\u00A01995.\u00C2\u00A0\u00C2\u00A0Jurassic\u00C2\u00A0and\u00C2\u00A0Early\u00C2\u00A0Cretaceous\u00C2\u00A0 island\u00C2\u00A0arc\u00C2\u00A0volcanism,\u00C2\u00A0extension,\u00C2\u00A0and\u00C2\u00A0subsidence\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Coast\u00C2\u00A0Range\u00C2\u00A0of\u00C2\u00A0central\u00C2\u00A0Chile.\u00C2\u00A0 Geological\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0America\u00C2\u00A0Bulletin,\u00C2\u00A0107:\u00C2\u00A01427\u00E2\u0080\u00901440.\u00C2\u00A0 \u00C2\u00A0 Viramonte,\u00C2\u00A0J.\u00C2\u00A0G.,\u00C2\u00A0Kay,\u00C2\u00A0S.\u00C2\u00A0M.,\u00C2\u00A0Becchio,\u00C2\u00A0R.,\u00C2\u00A0Escayola,\u00C2\u00A0M.,\u00C2\u00A0and\u00C2\u00A0Novitski,\u00C2\u00A0I.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A01999.\u00C2\u00A0\u00C2\u00A0Cretaceous\u00C2\u00A0rift\u00C2\u00A0 related\u00C2\u00A0magmatism\u00C2\u00A0in\u00C2\u00A0central\u00E2\u0080\u0090western\u00C2\u00A0South\u00C2\u00A0America.\u00C2\u00A0\u00C2\u00A0Journal\u00C2\u00A0of\u00C2\u00A0South\u00C2\u00A0American\u00C2\u00A0Earth\u00C2\u00A0 Sciences,\u00C2\u00A012:\u00C2\u00A0109\u00E2\u0080\u0090121.\u00C2\u00A0 \u00C2\u00A0 Winchester,\u00C2\u00A0J.A.\u00C2\u00A0and\u00C2\u00A0Floyd,\u00C2\u00A0P.A.\u00C2\u00A0\u00C2\u00A01977.\u00C2\u00A0\u00C2\u00A0Geochemical\u00C2\u00A0discrimination\u00C2\u00A0of\u00C2\u00A0different\u00C2\u00A0magma\u00C2\u00A0series\u00C2\u00A0 and\u00C2\u00A0their\u00C2\u00A0differentiation\u00C2\u00A0products\u00C2\u00A0using\u00C2\u00A0immobile\u00C2\u00A0elements,\u00C2\u00A0Chemical\u00C2\u00A0Geology,\u00C2\u00A020:\u00C2\u00A0325\u00E2\u0080\u0090343.\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Whalen,\u00C2\u00A0J.B.\u00C2\u00A0\u00C2\u00A01985.\u00C2\u00A0\u00C2\u00A0Geochemistry\u00C2\u00A0of\u00C2\u00A0an\u00C2\u00A0island\u00E2\u0080\u0090arc\u00C2\u00A0plutonic\u00C2\u00A0suite:\u00C2\u00A0the\u00C2\u00A0Uasilau\u00E2\u0080\u0090Yau\u00C2\u00A0Yau\u00C2\u00A0intrusive\u00C2\u00A0 complex,\u00C2\u00A0New\u00C2\u00A0Britain,\u00C2\u00A0PNG.\u00C2\u00A0\u00C2\u00A0Journal\u00C2\u00A0of\u00C2\u00A0Petrology,\u00C2\u00A026:\u00C2\u00A0603\u00E2\u0080\u0093632.\u00C2\u00A0 \u00C2\u00A0 Whalen,\u00C2\u00A0J.B.,\u00C2\u00A0Currie,\u00C2\u00A0K.L.,\u00C2\u00A0Chappell,\u00C2\u00A0B.W.\u00C2\u00A0\u00C2\u00A01987.\u00C2\u00A0\u00C2\u00A0A\u00E2\u0080\u0090type\u00C2\u00A0granites:\u00C2\u00A0geochemical\u00C2\u00A0characteristics,\u00C2\u00A0 discrimination\u00C2\u00A0and\u00C2\u00A0petrogenesis.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0Contributions\u00C2\u00A0to\u00C2\u00A0Mineralogy\u00C2\u00A0and\u00C2\u00A0Petrology,\u00C2\u00A095:\u00C2\u00A0407\u00E2\u0080\u0093419.\u00C2\u00A0 \u00C2\u00A0 Winter,\u00C2\u00A0L.S.,\u00C2\u00A0Tosdal,\u00C2\u00A0R.M.,\u00C2\u00A0Franklin,\u00C2\u00A0J.M.,\u00C2\u00A0Tegart,\u00C2\u00A0P.\u00C2\u00A0\u00C2\u00A02004.\u00C2\u00A0A\u00C2\u00A0Reconstructed\u00C2\u00A0Cretaceous\u00C2\u00A0 Depositional\u00C2\u00A0Setting\u00C2\u00A0for\u00C2\u00A0Giant\u00C2\u00A0VMS\u00C2\u00A0Deposits\u00C2\u00A0at\u00C2\u00A0Tambogrande,\u00C2\u00A0Northwestern\u00C2\u00A0Peru.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0 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Wolf,\u00C2\u00A0M.B.\u00C2\u00A0and\u00C2\u00A0Wyllie,\u00C2\u00A0P.J.\u00C2\u00A0\u00C2\u00A01994.\u00C2\u00A0\u00C2\u00A0Dehydration\u00E2\u0080\u0090melting\u00C2\u00A0of\u00C2\u00A0amphibolite\u00C2\u00A0at\u00C2\u00A010\u00C2\u00A0kbar:\u00C2\u00A0the\u00C2\u00A0effect\u00C2\u00A0of\u00C2\u00A0 temperature\u00C2\u00A0and\u00C2\u00A0time.\u00C2\u00A0\u00C2\u00A0Contributions\u00C2\u00A0to\u00C2\u00A0Mineralogy\u00C2\u00A0and\u00C2\u00A0Petrology,\u00C2\u00A0115:\u00C2\u00A0369\u00E2\u0080\u0093383.\u00C2\u00A0 \u00C2\u00A0 Wood,\u00C2\u00A0D.A.\u00C2\u00A0\u00C2\u00A01980.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0application\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Th\u00E2\u0080\u0090Hf\u00E2\u0080\u0090Ta\u00C2\u00A0diagram\u00C2\u00A0to\u00C2\u00A0problems\u00C2\u00A0of\u00C2\u00A0tectonomagmatic\u00C2\u00A0 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Chapter\u00C2\u00A05.\u00C2\u00A0\u00C2\u00A0Pb\u00E2\u0080\u0090Sr\u00E2\u0080\u0090Nd\u00C2\u00A0Isotope\u00C2\u00A0Systematics\u00C2\u00A0of\u00C2\u00A0Cretaceous\u00C2\u00A0Arc\u00C2\u00A0Volcanic\u00C2\u00A0Rocks\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0 Basin\u00C2\u00A0near\u00C2\u00A0Tambogrande,\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A0Implications\u00C2\u00A0for\u00C2\u00A0VMS\u00C2\u00A0Deposit\u00C2\u00A0Formation6\u00C2\u00A0 \u00C2\u00A0 5.1\u00C2\u00A0 Overview\u00C2\u00A0 Radiogenic\u00C2\u00A0(Pb\u00E2\u0080\u0090Nd\u00E2\u0080\u0090Sr)\u00C2\u00A0isotope\u00C2\u00A0data\u00C2\u00A0for\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0and\u00C2\u00A0sulphide\u00C2\u00A0minerals\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A0 Cretaceous\u00C2\u00A0Cu\u00E2\u0080\u0090Zn\u00E2\u0080\u0090Au\u00E2\u0080\u0090Ag\u00C2\u00A0volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0(VMS)\u00C2\u00A0deposits\u00C2\u00A0at\u00C2\u00A0Tambogrande,\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0 permit\u00C2\u00A0a\u00C2\u00A0better\u00C2\u00A0understanding\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0tectonomagmatic\u00C2\u00A0setting\u00C2\u00A0in\u00C2\u00A0which\u00C2\u00A0the\u00C2\u00A0deposits\u00C2\u00A0formed\u00C2\u00A0and\u00C2\u00A0 help\u00C2\u00A0constrain\u00C2\u00A0metal\u00C2\u00A0sources\u00C2\u00A0and\u00C2\u00A0models\u00C2\u00A0of\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0formation.\u00C2\u00A0\u00C2\u00A0Based\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0trace\u00C2\u00A0 element\u00C2\u00A0and\u00C2\u00A0isotope\u00C2\u00A0compositions,\u00C2\u00A0bimodal\u00C2\u00A0mafic\u00C2\u00A0to\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0have\u00C2\u00A0a\u00C2\u00A0 common\u00C2\u00A0parentage\u00C2\u00A0but\u00C2\u00A0are\u00C2\u00A0not\u00C2\u00A0related\u00C2\u00A0solely\u00C2\u00A0by\u00C2\u00A0fractional\u00C2\u00A0crystallization.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0Rather,\u00C2\u00A0magma\u00C2\u00A0 genesis\u00C2\u00A0occurred\u00C2\u00A0at\u00C2\u00A0multiple\u00C2\u00A0stages\u00C2\u00A0at\u00C2\u00A0various\u00C2\u00A0crustal\u00C2\u00A0levels\u00C2\u00A0and\u00C2\u00A0likely\u00C2\u00A0involved\u00C2\u00A0recycling\u00C2\u00A0of\u00C2\u00A0 juvenile\u00C2\u00A0arc\u00C2\u00A0crust\u00C2\u00A0as\u00C2\u00A0well\u00C2\u00A0as\u00C2\u00A0contamination\u00C2\u00A0with\u00C2\u00A0older\u00C2\u00A0continental\u00C2\u00A0crust.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 VMS\u00E2\u0080\u0090associated\u00C2\u00A0mafic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0yield\u00C2\u00A0Nd\u00C2\u00A0(\u00CE\u00B5Nd\u00CE\u00AF\u00C2\u00A0=\u00C2\u00A04.73\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A05.93),\u00C2\u00A0Pb\u00C2\u00A0( 206Pb/204Pb\u00C2\u00A0=\u00C2\u00A018.94\u00C2\u00A0to\u00C2\u00A0 19.02,\u00C2\u00A0207Pb/204Pb\u00C2\u00A0=\u00C2\u00A015.66\u00C2\u00A0to\u00C2\u00A015.68),\u00C2\u00A0and\u00C2\u00A0Sr\u00C2\u00A0isotopic\u00C2\u00A0ratios\u00C2\u00A0(87Sr/86Sr\u00CE\u00AF\u00C2\u00A0=\u00C2\u00A00.7036\u00E2\u0080\u00900.7042)\u00C2\u00A0most\u00C2\u00A0akin\u00C2\u00A0 to\u00C2\u00A0ocean\u00C2\u00A0arc\u00C2\u00A0settings.\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0isotopic\u00C2\u00A0values\u00C2\u00A0reflect\u00C2\u00A0binary\u00C2\u00A0mixing\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0depleted\u00C2\u00A0mantle\u00C2\u00A0source\u00C2\u00A0 (i.e.,\u00C2\u00A0mantle\u00E2\u0080\u0090wedge)\u00C2\u00A0and\u00C2\u00A0a\u00C2\u00A0subducted\u00C2\u00A0slab\u00C2\u00A0component\u00C2\u00A0consistent\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0inferred\u00C2\u00A0tectonic\u00C2\u00A0 setting\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0western\u00C2\u00A0South\u00C2\u00A0American\u00C2\u00A0continental\u00C2\u00A0margin\u00C2\u00A0during\u00C2\u00A0the\u00C2\u00A0mid\u00C2\u00A0Cretaceous.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0 slab\u00C2\u00A0component\u00C2\u00A0was\u00C2\u00A0inherited\u00C2\u00A0either\u00C2\u00A0through\u00C2\u00A0subduction\u00C2\u00A0of\u00C2\u00A0continental\u00C2\u00A0crust\u00E2\u0080\u0090derived\u00C2\u00A0 sedimentary\u00C2\u00A0rocks\u00C2\u00A0and/or\u00C2\u00A0possibly\u00C2\u00A0by\u00C2\u00A0direct\u00C2\u00A0assimilation\u00C2\u00A0during\u00C2\u00A0ascent\u00C2\u00A0of\u00C2\u00A0magmas\u00C2\u00A0through\u00C2\u00A0the\u00C2\u00A0 upper\u00C2\u00A0crust.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0(\u00CE\u00B5Nd\u00CE\u00AF\u00C2\u00A0=\u00C2\u00A01.85\u00C2\u00A0to\u00C2\u00A05.59)\u00C2\u00A0are\u00C2\u00A0up\u00C2\u00A0to\u00C2\u00A04\u00C2\u00A0\u00CE\u00B5Nd\u00C2\u00A0units\u00C2\u00A0lower,\u00C2\u00A0on\u00C2\u00A0average,\u00C2\u00A0than\u00C2\u00A0the\u00C2\u00A0 mafic\u00C2\u00A0volcanic\u00C2\u00A0rocks,\u00C2\u00A0yield\u00C2\u00A0significantly\u00C2\u00A0higher\u00C2\u00A0206Pb/204Pb\u00C2\u00A0ratios\u00C2\u00A0(19.64\u00C2\u00A0to\u00C2\u00A020.35)\u00C2\u00A0and\u00C2\u00A0define\u00C2\u00A0a\u00C2\u00A0 relatively\u00C2\u00A0flat\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0array\u00C2\u00A0extending\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0basalt\u00C2\u00A0field\u00C2\u00A0to\u00C2\u00A0a\u00C2\u00A0more\u00C2\u00A0radiogenic\u00C2\u00A0crustal\u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 6 A version of this chapter will be submitted for publication. Winter, L.S. and Tosdal, R., Pb-Sr-Nd Isotope Systematics of Cretaceous Arc Volcanic Rocks in the Lancones Basin near Tambogrande, Per\u00C3\u00BA \u00E2\u0080\u0093 Implications for VMS deposit formation. Chapter\u00C2\u00A05\u00C2\u00A0 Page\u00C2\u00A0142\u00C2\u00A0 \u00C2\u00A0 source\u00C2\u00A0(i.e.,\u00C2\u00A0Olmos\u00C2\u00A0Complex).\u00C2\u00A0\u00C2\u00A0Sr\u00C2\u00A0isotope\u00C2\u00A0data\u00C2\u00A0for\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0(87Sr/86Sr\u00CE\u00AF\u00C2\u00A0=\u00C2\u00A00.7045\u00E2\u0080\u0090 0.7050)\u00C2\u00A0yield\u00C2\u00A0ratios\u00C2\u00A0similar\u00C2\u00A0but\u00C2\u00A0slightly\u00C2\u00A0greater\u00C2\u00A0than\u00C2\u00A0associated\u00C2\u00A0mafic\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0 rocks\u00C2\u00A0originated\u00C2\u00A0from\u00C2\u00A0a\u00C2\u00A0melt\u00C2\u00A0of\u00C2\u00A0direct\u00C2\u00A0basalt\u00C2\u00A0parentage\u00C2\u00A0or\u00C2\u00A0a\u00C2\u00A0partial\u00C2\u00A0melt\u00C2\u00A0of\u00C2\u00A0juvenile\u00C2\u00A0mafic\u00C2\u00A0crust\u00C2\u00A0 and\u00C2\u00A0subsequent\u00C2\u00A0assimilation\u00C2\u00A0of\u00C2\u00A0radiogenic\u00C2\u00A0continental\u00C2\u00A0crust\u00C2\u00A0at\u00C2\u00A0upper\u00C2\u00A0crustal\u00C2\u00A0levels.\u00C2\u00A0\u00C2\u00A0Proterozoic\u00C2\u00A0 to\u00C2\u00A0Paleozoic\u00C2\u00A0basement\u00C2\u00A0rocks\u00C2\u00A0and\u00C2\u00A0derived\u00C2\u00A0sedimentary\u00C2\u00A0successions,\u00C2\u00A0exposed\u00C2\u00A0adjacent\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0 Cretaceous\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0in\u00C2\u00A0northwestern\u00C2\u00A0Per\u00C3\u00BA,\u00C2\u00A0are\u00C2\u00A0the\u00C2\u00A0probable\u00C2\u00A0source\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0crustal\u00C2\u00A0 contamination.\u00C2\u00A0 Pb\u00C2\u00A0isotopic\u00C2\u00A0data\u00C2\u00A0for\u00C2\u00A0each\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0three\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0define\u00C2\u00A0a\u00C2\u00A0narrow\u00C2\u00A0range\u00C2\u00A0 of\u00C2\u00A0values\u00C2\u00A0(206Pb/204Pb\u00C2\u00A0=18.87\u00C2\u00A0to\u00C2\u00A018.93,\u00C2\u00A0207Pb/204Pb\u00C2\u00A0=\u00C2\u00A015.67\u00C2\u00A0to\u00C2\u00A015.70,\u00C2\u00A0208Pb/204Pb\u00C2\u00A0=\u00C2\u00A038.71\u00C2\u00A0to\u00C2\u00A038.85)\u00C2\u00A0 and\u00C2\u00A0define\u00C2\u00A0steep\u00C2\u00A0arrays\u00C2\u00A0on\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0plots.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0data\u00C2\u00A0indicate\u00C2\u00A0a\u00C2\u00A0uniform\u00C2\u00A0source\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0lead,\u00C2\u00A0and\u00C2\u00A0 by\u00C2\u00A0inference\u00C2\u00A0the\u00C2\u00A0other\u00C2\u00A0metals,\u00C2\u00A0in\u00C2\u00A0these\u00C2\u00A0deposits,\u00C2\u00A0perhaps\u00C2\u00A0extracted\u00C2\u00A0during\u00C2\u00A0a\u00C2\u00A0common\u00C2\u00A0 hydrothermal\u00C2\u00A0system.\u00C2\u00A0\u00C2\u00A0Hydrothermal\u00C2\u00A0leaching\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0basalt\u00E2\u0080\u0090dominated\u00C2\u00A0substrate\u00C2\u00A0is\u00C2\u00A0considered\u00C2\u00A0the\u00C2\u00A0 dominant\u00C2\u00A0process\u00C2\u00A0of\u00C2\u00A0lead\u00C2\u00A0addition\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0mineralizing\u00C2\u00A0fluids,\u00C2\u00A0with\u00C2\u00A0no\u00C2\u00A0apparent\u00C2\u00A0contribution\u00C2\u00A0from\u00C2\u00A0 the\u00C2\u00A0more\u00C2\u00A0radiogenic\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0or\u00C2\u00A0the\u00C2\u00A0continental\u00C2\u00A0crust\u00C2\u00A0from\u00C2\u00A0which\u00C2\u00A0the\u00C2\u00A0felsic\u00C2\u00A0rocks\u00C2\u00A0 derive\u00C2\u00A0their\u00C2\u00A0isotopic\u00C2\u00A0signature.\u00C2\u00A0\u00C2\u00A0Despite\u00C2\u00A0derivation\u00C2\u00A0or\u00C2\u00A0modification\u00C2\u00A0at\u00C2\u00A0a\u00C2\u00A0shallow\u00C2\u00A0crustal\u00C2\u00A0level,\u00C2\u00A0felsic\u00C2\u00A0 source\u00C2\u00A0melt\u00C2\u00A0regions\u00C2\u00A0and\u00C2\u00A0continental\u00C2\u00A0crust\u00C2\u00A0were\u00C2\u00A0likely\u00C2\u00A0beyond\u00C2\u00A0the\u00C2\u00A0deepest\u00C2\u00A0reaches\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 hydrothermal\u00C2\u00A0system.\u00C2\u00A0\u00C2\u00A0Therefore,\u00C2\u00A0although\u00C2\u00A0the\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0yield\u00C2\u00A0an\u00C2\u00A0important\u00C2\u00A0spatial\u00C2\u00A0and\u00C2\u00A0 temporal\u00C2\u00A0association\u00C2\u00A0with\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0at\u00C2\u00A0Tambogrande,\u00C2\u00A0there\u00C2\u00A0is\u00C2\u00A0no\u00C2\u00A0evidence\u00C2\u00A0for\u00C2\u00A0a\u00C2\u00A0 causal\u00C2\u00A0link\u00C2\u00A0(i.e.,\u00C2\u00A0no\u00C2\u00A0leaching\u00C2\u00A0or\u00C2\u00A0magmatic\u00C2\u00A0fluid\u00C2\u00A0contribution).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0presence\u00C2\u00A0of\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0 in\u00C2\u00A0the\u00C2\u00A0host\u00C2\u00A0rock\u00C2\u00A0sequence\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0is\u00C2\u00A0most\u00C2\u00A0likely\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0melting\u00C2\u00A0of\u00C2\u00A0hydrated\u00C2\u00A0basaltic\u00C2\u00A0 crust\u00C2\u00A0and\u00C2\u00A0is\u00C2\u00A0a\u00C2\u00A0function\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0thermal\u00C2\u00A0anomaly\u00C2\u00A0which\u00C2\u00A0drove\u00C2\u00A0the\u00C2\u00A0hydrothermal\u00C2\u00A0convection.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Chapter\u00C2\u00A05\u00C2\u00A0 Page\u00C2\u00A0143\u00C2\u00A0 \u00C2\u00A0 5.2\u00C2\u00A0 Introduction\u00C2\u00A0 The\u00C2\u00A0Tambogrande\u00C2\u00A0district\u00C2\u00A0of\u00C2\u00A0northwestern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0is\u00C2\u00A0hosted\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0Cretaceous\u00C2\u00A0marine\u00C2\u00A0volcanic\u00C2\u00A0 and\u00C2\u00A0sedimentary\u00C2\u00A0succession\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0district\u00C2\u00A0hosts\u00C2\u00A0a\u00C2\u00A0cluster\u00C2\u00A0of\u00C2\u00A0anomalously\u00C2\u00A0 large\u00C2\u00A0deposits\u00C2\u00A0of\u00C2\u00A0base\u00E2\u0080\u0090\u00C2\u00A0and\u00C2\u00A0precious\u00E2\u0080\u0090metal\u00E2\u0080\u0090bearing\u00C2\u00A0volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0(VMS)\u00C2\u00A0 deposits\u00C2\u00A0around\u00C2\u00A0Tambogrande\u00C2\u00A0(Fig.\u00C2\u00A05.1,\u00C2\u00A05.2;\u00C2\u00A0Tegart\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02000;\u00C2\u00A0Chapter\u00C2\u00A01).\u00C2\u00A0\u00C2\u00A0On\u00C2\u00A0a\u00C2\u00A0grade\u00E2\u0080\u0090 tonnage\u00C2\u00A0basis,\u00C2\u00A0the\u00C2\u00A0Tambogrande\u00C2\u00A0deposits\u00C2\u00A0are\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0upper\u00C2\u00A03%\u00C2\u00A0of\u00C2\u00A0all\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0of\u00C2\u00A0their\u00C2\u00A0 type\u00C2\u00A0globally\u00C2\u00A0(Franklin\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02005)\u00C2\u00A0and\u00C2\u00A0are\u00C2\u00A0classified\u00C2\u00A0as\u00C2\u00A0bi\u00E2\u0080\u0090modal\u00C2\u00A0mafic\u00C2\u00A0type\u00C2\u00A0according\u00C2\u00A0to\u00C2\u00A0Barrie\u00C2\u00A0 and\u00C2\u00A0Hannington\u00C2\u00A0(1999).\u00C2\u00A0\u00C2\u00A0Analogous\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0are\u00C2\u00A0of\u00C2\u00A0Archean\u00C2\u00A0age\u00C2\u00A0(e.g.,\u00C2\u00A0Noranda\u00C2\u00A0camp,\u00C2\u00A0 Gibson\u00C2\u00A0and\u00C2\u00A0Watkinson,\u00C2\u00A01990;\u00C2\u00A0Kidd\u00C2\u00A0Creek,\u00C2\u00A0Hannington\u00C2\u00A0and\u00C2\u00A0Barrie,\u00C2\u00A01999),\u00C2\u00A0Proterozoic\u00C2\u00A0age\u00C2\u00A0(e.g.,\u00C2\u00A0 Flin\u00C2\u00A0Flon,\u00C2\u00A0Syme\u00C2\u00A0and\u00C2\u00A0Bailes,\u00C2\u00A01993)\u00C2\u00A0and\u00C2\u00A0Phanerozoic\u00C2\u00A0age\u00C2\u00A0(e.g.,\u00C2\u00A0Sibai\u00C2\u00A0and\u00C2\u00A0Gai,\u00C2\u00A0Herrington\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A0 2005a,b).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0deposits\u00C2\u00A0are\u00C2\u00A0the\u00C2\u00A0largest\u00C2\u00A0Mesozoic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0and\u00C2\u00A0are\u00C2\u00A0the\u00C2\u00A0 most\u00C2\u00A0potentially\u00C2\u00A0economic\u00C2\u00A0group\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0South\u00C2\u00A0America.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0 contains\u00C2\u00A0three\u00C2\u00A0deposits\u00C2\u00A0(Fig.\u00C2\u00A05.2b):\u00C2\u00A0(i)\u00C2\u00A0TG1\u00C2\u00A0with\u00C2\u00A0109\u00C2\u00A0Mt\u00C2\u00A0tons\u00C2\u00A0grading\u00C2\u00A01.6%\u00C2\u00A0Cu,\u00C2\u00A01.0%\u00C2\u00A0Zn,\u00C2\u00A00.5\u00C2\u00A0g/t\u00C2\u00A0 Au\u00C2\u00A0and\u00C2\u00A022\u00C2\u00A0g/t\u00C2\u00A0Ag,\u00C2\u00A0(ii)\u00C2\u00A0TG3\u00C2\u00A0with\u00C2\u00A082\u00C2\u00A0Mt\u00C2\u00A0grading\u00C2\u00A01.0%\u00C2\u00A0Cu,\u00C2\u00A01.4%\u00C2\u00A0Zn,\u00C2\u00A00.8\u00C2\u00A0g/t\u00C2\u00A0Au\u00C2\u00A0and\u00C2\u00A025\u00C2\u00A0g/t\u00C2\u00A0Ag,\u00C2\u00A0and\u00C2\u00A0 (iii)\u00C2\u00A0B5,\u00C2\u00A0with\u00C2\u00A0comparable\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0intersections\u00C2\u00A0to\u00C2\u00A0TG1\u00C2\u00A0and\u00C2\u00A0TG3,\u00C2\u00A0but\u00C2\u00A0defined\u00C2\u00A0tonnage\u00C2\u00A0or\u00C2\u00A0 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for\u00C2\u00A0older\u00C2\u00A0metamorphosed\u00C2\u00A0igneous\u00C2\u00A0and\u00C2\u00A0sedimentary\u00C2\u00A0rocks,\u00C2\u00A0help\u00C2\u00A0establish\u00C2\u00A0a\u00C2\u00A0regional\u00C2\u00A0isotopic\u00C2\u00A0 Chapter\u00C2\u00A05\u00C2\u00A0 Page\u00C2\u00A0144\u00C2\u00A0 \u00C2\u00A0 framework.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0isotopic\u00C2\u00A0data\u00C2\u00A0illustrate\u00C2\u00A0the\u00C2\u00A0relative\u00C2\u00A0contributions\u00C2\u00A0of\u00C2\u00A0various\u00C2\u00A0continental\u00C2\u00A0crust\u00C2\u00A0 and\u00C2\u00A0mantle\u00C2\u00A0sources\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0petrogenesis\u00C2\u00A0of\u00C2\u00A0these\u00C2\u00A0volcanic\u00C2\u00A0rocks,\u00C2\u00A0which\u00C2\u00A0in\u00C2\u00A0turn\u00C2\u00A0assists\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0 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The\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0represents\u00C2\u00A0the\u00C2\u00A0northern\u00C2\u00A0portion\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0much\u00C2\u00A0larger\u00C2\u00A0and\u00C2\u00A0segmented,\u00C2\u00A0Mesozoic\u00C2\u00A0 continental\u00C2\u00A0margin\u00C2\u00A0rift\u00C2\u00A0basin\u00C2\u00A0extending\u00C2\u00A0southwards\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0Peruvian\u00C2\u00A0coast\u00C2\u00A0(Huarmey\u00E2\u0080\u0090Ca\u00C3\u00B1ete\u00C2\u00A0 Marginal\u00C2\u00A0Trough;\u00C2\u00A0Atherton\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01983;\u00C2\u00A0Benavides\u00E2\u0080\u0090C\u00C3\u00A1ceres,\u00C2\u00A01999)\u00C2\u00A0and\u00C2\u00A0also\u00C2\u00A0into\u00C2\u00A0southwest\u00C2\u00A0 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to\u00C2\u00A0the\u00C2\u00A0present\u00C2\u00A0day.\u00C2\u00A0 Located\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0Huancabamba\u00C2\u00A0deflection,\u00C2\u00A0a\u00C2\u00A0major\u00C2\u00A0oroclinal\u00C2\u00A0bend\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Andes\u00C2\u00A0which\u00C2\u00A0 separates\u00C2\u00A0the\u00C2\u00A0north\u00E2\u0080\u0090northwest\u00E2\u0080\u0090trending\u00C2\u00A0Peruvian\u00C2\u00A0Andes\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0northeast\u00E2\u0080\u0090trending\u00C2\u00A0 Ecuadorian\u00C2\u00A0Andes,\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0records\u00C2\u00A0a\u00C2\u00A0sequence\u00C2\u00A0of\u00C2\u00A0accretionary\u00C2\u00A0events\u00C2\u00A0and\u00C2\u00A0 contractional\u00C2\u00A0and\u00C2\u00A0extensional\u00C2\u00A0rotations\u00C2\u00A0(Mitouard\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01990;\u00C2\u00A0Fig\u00C2\u00A05.1).\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0tectonic\u00C2\u00A0 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terranes\u00C2\u00A0comprised\u00C2\u00A0of\u00C2\u00A0mid\u00E2\u0080\u0090ocean\u00C2\u00A0ridge\u00C2\u00A0(N\u00E2\u0080\u0090MORB)\u00C2\u00A0and\u00C2\u00A0oceanic\u00C2\u00A0plateau\u00C2\u00A0basalts\u00C2\u00A0(e.g.,\u00C2\u00A0Raspas\u00C2\u00A0 metamorphic\u00C2\u00A0complex;\u00C2\u00A0Arculus\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01999;\u00C2\u00A0Bosch\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02002).\u00C2\u00A0\u00C2\u00A0Mourier\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1988)\u00C2\u00A0suggest\u00C2\u00A0 the\u00C2\u00A0Amotape\u00C2\u00A0terrane\u00C2\u00A0arrived\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0south\u00C2\u00A0and\u00C2\u00A0developed\u00C2\u00A0northeast\u00E2\u0080\u0090trending\u00C2\u00A0dextral\u00C2\u00A0faults\u00C2\u00A0 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to\u00C2\u00A0be\u00C2\u00A0equivalent\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0Mara\u00C3\u00B1on\u00C2\u00A0Geanticline\u00C2\u00A0(Cobbing\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01981;\u00C2\u00A0Reyes\u00C2\u00A0and\u00C2\u00A0Caldas,\u00C2\u00A01987;\u00C2\u00A0 Mourier\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01988;\u00C2\u00A0Litherland\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01994).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0Olmos\u00C2\u00A0and\u00C2\u00A0Amotape\u00C2\u00A0Complexes\u00C2\u00A0represent\u00C2\u00A0the\u00C2\u00A0Jurassic\u00C2\u00A0to\u00C2\u00A0Early\u00C2\u00A0Cretaceous\u00C2\u00A0pre\u00E2\u0080\u0090rift\u00C2\u00A0 Andean\u00C2\u00A0margin\u00C2\u00A0and\u00C2\u00A0acted\u00C2\u00A0as\u00C2\u00A0topographical\u00C2\u00A0highs\u00C2\u00A0during\u00C2\u00A0Mesozoic\u00C2\u00A0times\u00C2\u00A0and\u00C2\u00A0controlled\u00C2\u00A0marine\u00C2\u00A0 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The\u00C2\u00A0Sr\u00C2\u00A0and\u00C2\u00A0Nd\u00C2\u00A0isotopic\u00C2\u00A0framework\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0Andes\u00C2\u00A0is\u00C2\u00A0less\u00C2\u00A0well\u00C2\u00A0established\u00C2\u00A0in\u00C2\u00A0comparison\u00C2\u00A0to\u00C2\u00A0Pb,\u00C2\u00A0 however,\u00C2\u00A0data\u00C2\u00A0are\u00C2\u00A0available\u00C2\u00A0for\u00C2\u00A0major\u00C2\u00A0geologic\u00C2\u00A0units\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0northern\u00C2\u00A0Andes\u00C2\u00A0(Fig.\u00C2\u00A05.10A).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0 Olmos\u00C2\u00A0Complex,\u00C2\u00A0basement\u00C2\u00A0rocks\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0Cretaceous\u00C2\u00A0marginal\u00C2\u00A0rift\u00C2\u00A0basins,\u00C2\u00A0yield\u00C2\u00A0relatively\u00C2\u00A0high\u00C2\u00A0 87Sr/86Srpresent\u00E2\u0080\u0090day\u00C2\u00A0(0.732\u00E2\u0080\u00900.741)\u00C2\u00A0and\u00C2\u00A0low\u00C2\u00A0\u00CE\u00B5Nd\u00C2\u00A0present\u00E2\u0080\u0090day\u00C2\u00A0(\u00E2\u0080\u009012.1\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0\u00E2\u0080\u009011.5)\u00C2\u00A0typical\u00C2\u00A0of\u00C2\u00A0highly\u00C2\u00A0radiogenic\u00C2\u00A0 lower\u00C2\u00A0crustal\u00C2\u00A0rocks,\u00C2\u00A0whereas\u00C2\u00A0overlying\u00C2\u00A0Cretaceous\u00C2\u00A0sedimentary\u00C2\u00A0rocks\u00C2\u00A0have\u00C2\u00A0comparatively\u00C2\u00A0lower\u00C2\u00A0 87Sr/86Srpresent\u00E2\u0080\u0090day\u00C2\u00A0(0.708\u00E2\u0080\u00900.725)\u00C2\u00A0but\u00C2\u00A0similar\u00C2\u00A0\u00CE\u00B5Nd\u00C2\u00A0present\u00E2\u0080\u0090day\u00C2\u00A0(\u00E2\u0080\u009016.5\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0\u00E2\u0080\u009011.7;\u00C2\u00A0Macfarlane,\u00C2\u00A01999).\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0the\u00C2\u00A0 Jurassic\u00E2\u0080\u0090Cretaceous\u00C2\u00A0Raspas\u00C2\u00A0Metamorphic\u00C2\u00A0Complex,\u00C2\u00A0metapelite\u00C2\u00A0yields\u00C2\u00A0moderately\u00C2\u00A0high\u00C2\u00A0initial\u00C2\u00A0 87Sr/86Srpresent\u00E2\u0080\u0090day\u00C2\u00A0(0.716\u00E2\u0080\u00900.718)\u00C2\u00A0and\u00C2\u00A0\u00CE\u00B5Nd\u00C2\u00A0present\u00E2\u0080\u0090day\u00C2\u00A0(\u00E2\u0080\u00906.8\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0\u00E2\u0080\u00909.9),\u00C2\u00A0whereas\u00C2\u00A0metabasalts\u00C2\u00A0yield\u00C2\u00A0MORB\u00E2\u0080\u0090 like\u00C2\u00A087Sr/86Sr\u00C2\u00A0\u00C2\u00A0(0.707)\u00C2\u00A0and\u00C2\u00A0\u00CE\u00B5Ndpresent\u00E2\u0080\u0090day\u00C2\u00A0=\u00C2\u00A010.6\u00C2\u00A0(Bosch\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02002).\u00C2\u00A0\u00C2\u00A0Post\u00E2\u0080\u0090rift\u00C2\u00A0granitoid\u00C2\u00A0intrusions\u00C2\u00A0 (87Sr/86Sr\u00C2\u00A0\u00C2\u00A0=\u00C2\u00A00.70351\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A00.7051)\u00C2\u00A0are\u00C2\u00A0generally\u00C2\u00A0considered\u00C2\u00A0to\u00C2\u00A0be\u00C2\u00A0the\u00C2\u00A0result\u00C2\u00A0of\u00C2\u00A0subduction\u00C2\u00A0zone\u00C2\u00A0 enrichment\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0subcontinental\u00C2\u00A0mantle\u00C2\u00A0source\u00C2\u00A0and\u00C2\u00A0show\u00C2\u00A0limited\u00C2\u00A0contamination\u00C2\u00A0with\u00C2\u00A0radiogenic\u00C2\u00A0 upper\u00C2\u00A0crustal\u00C2\u00A0rocks\u00C2\u00A0(Soler\u00C2\u00A0and\u00C2\u00A0Rotach\u00E2\u0080\u0090Toulhoat,\u00C2\u00A01990).\u00C2\u00A0\u00C2\u00A0Sr\u00C2\u00A0and\u00C2\u00A0Nd\u00C2\u00A0data\u00C2\u00A0are\u00C2\u00A0not\u00C2\u00A0available\u00C2\u00A0for\u00C2\u00A0 Cretaceous\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0Peruvian\u00C2\u00A0marginal\u00C2\u00A0rift\u00C2\u00A0basins.\u00C2\u00A0 5.6\u00C2\u00A0 Pb,\u00C2\u00A0Sm\u00E2\u0080\u0090Nd\u00C2\u00A0and\u00C2\u00A0Rb\u00E2\u0080\u0090Sr\u00C2\u00A0Isotope\u00C2\u00A0Geochemistry\u00C2\u00A0 Twenty\u00E2\u0080\u0090two\u00C2\u00A0Pb\u00C2\u00A0isotopic\u00C2\u00A0measurements\u00C2\u00A0were\u00C2\u00A0made\u00C2\u00A0on\u00C2\u00A0\u00C2\u00A0sulphide\u00C2\u00A0minerals\u00C2\u00A0separates\u00C2\u00A0from\u00C2\u00A0 the\u00C2\u00A0TG1,\u00C2\u00A0TG3,\u00C2\u00A0and\u00C2\u00A0B5\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0(n=6)\u00C2\u00A0and\u00C2\u00A0whole\u00C2\u00A0rock\u00C2\u00A0samples\u00C2\u00A0of\u00C2\u00A0syn\u00E2\u0080\u0090mineralization\u00C2\u00A0 volcanic\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0vicinity\u00C2\u00A0of\u00C2\u00A0TG1\u00C2\u00A0and\u00C2\u00A0TG3\u00C2\u00A0(n=10)\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation.\u00C2\u00A0\u00C2\u00A0Pb\u00C2\u00A0 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12\u00C2\u00A0Sm\u00E2\u0080\u0090Nd\u00C2\u00A0and\u00C2\u00A0Rb\u00E2\u0080\u0090Sr\u00C2\u00A0isotope\u00C2\u00A0analyses\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0Sample\u00C2\u00A0locations\u00C2\u00A0are\u00C2\u00A0shown\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0 map\u00C2\u00A0in\u00C2\u00A0Figure\u00C2\u00A05.4\u00C2\u00A0and\u00C2\u00A0descriptions\u00C2\u00A0are\u00C2\u00A0provided\u00C2\u00A0in\u00C2\u00A0Tables\u00C2\u00A05.1\u00C2\u00A0and\u00C2\u00A05.2.\u00C2\u00A0\u00C2\u00A0All\u00C2\u00A0samples\u00C2\u00A0were\u00C2\u00A0 analyzed\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A0Pacific\u00C2\u00A0Centre\u00C2\u00A0for\u00C2\u00A0Isotopic\u00C2\u00A0and\u00C2\u00A0Geochemical\u00C2\u00A0Research\u00C2\u00A0(PCIGR),\u00C2\u00A0Department\u00C2\u00A0of\u00C2\u00A0 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3)\u00C2\u00A0\u00C2\u00A0Small\u00C2\u00A0(\u00E2\u0089\u00A41\u00C2\u00A0mm),\u00C2\u00A0clean\u00C2\u00A0galena\u00C2\u00A0crystals\u00C2\u00A0were\u00C2\u00A0dissolved\u00C2\u00A0in\u00C2\u00A02N\u00C2\u00A0hydrochloric\u00C2\u00A0acid,\u00C2\u00A0then\u00C2\u00A0rinsed\u00C2\u00A0in\u00C2\u00A0 4N\u00C2\u00A0hydrochloric\u00C2\u00A0acid\u00C2\u00A0to\u00C2\u00A0clean\u00C2\u00A0the\u00C2\u00A0resulting\u00C2\u00A0lead\u00C2\u00A0chloride\u00C2\u00A0crystals.\u00C2\u00A0\u00C2\u00A0Approximately\u00C2\u00A010\u00E2\u0080\u009025\u00C2\u00A0ng\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0lead\u00C2\u00A0in\u00C2\u00A0chloride\u00C2\u00A0form\u00C2\u00A0was\u00C2\u00A0loaded\u00C2\u00A0on\u00C2\u00A0a\u00C2\u00A0rhenium\u00C2\u00A0filament\u00C2\u00A0using\u00C2\u00A0a\u00C2\u00A0phosphoric\u00C2\u00A0acid\u00E2\u0080\u0090silica\u00C2\u00A0gel\u00C2\u00A0 emitter,\u00C2\u00A0and\u00C2\u00A0isotopic\u00C2\u00A0compositions\u00C2\u00A0were\u00C2\u00A0determined\u00C2\u00A0in\u00C2\u00A0peak\u00E2\u0080\u0090switching\u00C2\u00A0mode\u00C2\u00A0using\u00C2\u00A0a\u00C2\u00A0modified\u00C2\u00A0 VG54R\u00C2\u00A0thermal\u00C2\u00A0ionization\u00C2\u00A0mass\u00C2\u00A0spectrometer.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0measured\u00C2\u00A0ratios\u00C2\u00A0were\u00C2\u00A0corrected\u00C2\u00A0for\u00C2\u00A0 instrumental\u00C2\u00A0mass\u00C2\u00A0fractionation\u00C2\u00A0of\u00C2\u00A00.12%/amu\u00C2\u00A0(Faraday\u00C2\u00A0collector)\u00C2\u00A0per\u00C2\u00A0mass\u00C2\u00A0unit\u00C2\u00A0based\u00C2\u00A0on\u00C2\u00A0 repeated\u00C2\u00A0measurements\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0N.B.S.\u00C2\u00A0SRM\u00C2\u00A0981\u00C2\u00A0Standard\u00C2\u00A0Isotopic\u00C2\u00A0Reference\u00C2\u00A0Material\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0 Chapter\u00C2\u00A05\u00C2\u00A0 Page\u00C2\u00A0153\u00C2\u00A0 \u00C2\u00A0 values\u00C2\u00A0recommended\u00C2\u00A0by\u00C2\u00A0Thirlwall\u00C2\u00A0(2000).\u00C2\u00A0\u00C2\u00A0Errors\u00C2\u00A0were\u00C2\u00A0numerically\u00C2\u00A0propagated\u00C2\u00A0including\u00C2\u00A0all\u00C2\u00A0 mass\u00C2\u00A0fractionation\u00C2\u00A0and\u00C2\u00A0analytical\u00C2\u00A0errors,\u00C2\u00A0using\u00C2\u00A0the\u00C2\u00A0technique\u00C2\u00A0of\u00C2\u00A0Roddick\u00C2\u00A0(1987).\u00C2\u00A0\u00C2\u00A0All\u00C2\u00A0errors\u00C2\u00A0are\u00C2\u00A0 quoted\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A02\u00CF\u0083\u00C2\u00A0level.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0analyses\u00C2\u00A0have\u00C2\u00A0been\u00C2\u00A0plotted\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0average\u00C2\u00A0crust\u00C2\u00A0model\u00C2\u00A0lead\u00C2\u00A0 growth\u00C2\u00A0curve\u00C2\u00A0of\u00C2\u00A0Stacey\u00C2\u00A0and\u00C2\u00A0Kramers\u00C2\u00A0(1975)\u00C2\u00A0for\u00C2\u00A0comparison.\u00C2\u00A0Age\u00C2\u00A0assignments\u00C2\u00A0follow\u00C2\u00A0the\u00C2\u00A0time\u00C2\u00A0 scale\u00C2\u00A0of\u00C2\u00A0Harland\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1990).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0total\u00C2\u00A0procedural\u00C2\u00A0blank\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0trace\u00C2\u00A0lead\u00C2\u00A0chemistry\u00C2\u00A0was\u00C2\u00A064\u00C2\u00A0pg.\u00C2\u00A0 5.7.2\u00C2\u00A0 Pb,\u00C2\u00A0Rb\u00E2\u0080\u0090Sr,\u00C2\u00A0Sm\u00E2\u0080\u0090Nd\u00C2\u00A0Isotope\u00C2\u00A0Analysis,\u00C2\u00A0Whole\u00C2\u00A0Rock\u00C2\u00A0Samples\u00C2\u00A0 Isotopic\u00C2\u00A0composition\u00C2\u00A0measurements\u00C2\u00A0were\u00C2\u00A0determined\u00C2\u00A0on\u00C2\u00A0a\u00C2\u00A0Finnigan\u00C2\u00A0Triton\u00C2\u00A0thermo\u00E2\u0080\u0090 ionization\u00C2\u00A0mass\u00C2\u00A0spectrometer\u00C2\u00A0(TIMS;\u00C2\u00A0Sr,\u00C2\u00A0Nd)\u00C2\u00A0and\u00C2\u00A0on\u00C2\u00A0a\u00C2\u00A0Nu\u00C2\u00A0Instruments\u00C2\u00A0(Nu\u00C2\u00A0021)\u00C2\u00A0multiple\u00C2\u00A0 collector\u00C2\u00A0inductively\u00C2\u00A0coupled\u00C2\u00A0plasma\u00C2\u00A0mass\u00C2\u00A0spectrometer\u00C2\u00A0(MC\u00E2\u0080\u0090ICP\u00E2\u0080\u0090MS;\u00C2\u00A0Pb)\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A0Pacific\u00C2\u00A0Centre\u00C2\u00A0 for\u00C2\u00A0Isotopic\u00C2\u00A0and\u00C2\u00A0Geochemical\u00C2\u00A0Research\u00C2\u00A0(PCIGR)\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A0University\u00C2\u00A0of\u00C2\u00A0British\u00C2\u00A0Columbia.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0 complete\u00C2\u00A0methodology\u00C2\u00A0is\u00C2\u00A0described\u00C2\u00A0by\u00C2\u00A0Weiss\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(2005).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Sr\u00C2\u00A0and\u00C2\u00A0Nd\u00C2\u00A0compositions\u00C2\u00A0were\u00C2\u00A0measured\u00C2\u00A0in\u00C2\u00A0static\u00C2\u00A0mode\u00C2\u00A0multicollection\u00C2\u00A0with\u00C2\u00A0relay\u00C2\u00A0matrix\u00C2\u00A0 rotation\u00C2\u00A0(the\u00C2\u00A0\u00E2\u0080\u009Cvirtual\u00C2\u00A0amplifier\u00E2\u0080\u009D\u00C2\u00A0of\u00C2\u00A0Finnigan)\u00C2\u00A0on\u00C2\u00A0a\u00C2\u00A0single\u00C2\u00A0Ta\u00C2\u00A0and\u00C2\u00A0double\u00C2\u00A0Re\u00E2\u0080\u0090Ta\u00C2\u00A0filament,\u00C2\u00A0 respectively.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0data\u00C2\u00A0were\u00C2\u00A0corrected\u00C2\u00A0for\u00C2\u00A0mass\u00C2\u00A0fractionation\u00C2\u00A0using\u00C2\u00A086Sr/88Sr\u00C2\u00A0=\u00C2\u00A00.1194\u00C2\u00A0and\u00C2\u00A0 146Nd/144Nd\u00C2\u00A0=\u00C2\u00A00.7219,\u00C2\u00A0respectively.\u00C2\u00A0\u00C2\u00A0Fifty\u00E2\u0080\u0090five\u00C2\u00A0analyses\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0NIST\u00C2\u00A0SRM\u00C2\u00A0987\u00C2\u00A0Sr\u00C2\u00A0standard\u00C2\u00A0and\u00C2\u00A0 seventy\u00E2\u0080\u0090six\u00C2\u00A0analyses\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0La\u00C2\u00A0Jolla\u00C2\u00A0Nd\u00C2\u00A0standard\u00C2\u00A0made\u00C2\u00A0during\u00C2\u00A0the\u00C2\u00A0course\u00C2\u00A0of\u00C2\u00A0this\u00C2\u00A0study\u00C2\u00A0have\u00C2\u00A0 mean\u00C2\u00A0values\u00C2\u00A0of\u00C2\u00A087Sr/86Sr\u00C2\u00A0=\u00C2\u00A00.710250\u00C2\u00A0\u00C2\u00B1\u00C2\u00A012\u00C2\u00A0(2SD)\u00C2\u00A0and\u00C2\u00A0143Nd/144Nd\u00C2\u00A0=\u00C2\u00A00.511853\u00C2\u00A0\u00C2\u00B1\u00C2\u00A016\u00C2\u00A0(2SD),\u00C2\u00A0 respectively.\u00C2\u00A0A\u00C2\u00A0single\u00C2\u00A0analysis\u00C2\u00A0typically\u00C2\u00A0consists\u00C2\u00A0of\u00C2\u00A0135\u00C2\u00A0cycles\u00C2\u00A0(9\u00C2\u00A0blocks\u00C2\u00A0of\u00C2\u00A015)\u00C2\u00A0to\u00C2\u00A0allow\u00C2\u00A0a\u00C2\u00A0full\u00C2\u00A0 rotation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0virtual\u00C2\u00A0amplifier.\u00C2\u00A0 Pb\u00C2\u00A0isotopic\u00C2\u00A0compositions\u00C2\u00A0were\u00C2\u00A0analyzed\u00C2\u00A0by\u00C2\u00A0static\u00C2\u00A0multicollection.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0collector\u00C2\u00A0array\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0 Nu\u00C2\u00A0Plasma\u00C2\u00A0is\u00C2\u00A0fixed\u00C2\u00A0and\u00C2\u00A0a\u00C2\u00A0zoom\u00C2\u00A0lens\u00C2\u00A0is\u00C2\u00A0employed\u00C2\u00A0to\u00C2\u00A0position\u00C2\u00A0the\u00C2\u00A0masses\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0collectors.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0 central\u00C2\u00A0collectors\u00C2\u00A0(H4\u00E2\u0080\u0090L2)\u00C2\u00A0are\u00C2\u00A01\u00C2\u00A0amu\u00C2\u00A0apart\u00C2\u00A0while\u00C2\u00A0the\u00C2\u00A0outer\u00C2\u00A0collectors\u00C2\u00A0(H6,\u00C2\u00A0H5,\u00C2\u00A0L3,\u00C2\u00A0L4\u00C2\u00A0and\u00C2\u00A0L5)\u00C2\u00A0are\u00C2\u00A0 2\u00C2\u00A0amu\u00C2\u00A0apart.\u00C2\u00A0\u00C2\u00A0Masses\u00C2\u00A0208\u00C2\u00A0to\u00C2\u00A0202\u00C2\u00A0are\u00C2\u00A0measured\u00C2\u00A0in\u00C2\u00A0collectors\u00C2\u00A0H4\u00C2\u00A0to\u00C2\u00A0L2.\u00C2\u00A0 Chapter\u00C2\u00A05\u00C2\u00A0 Page\u00C2\u00A0154\u00C2\u00A0 \u00C2\u00A0 5.8\u00C2\u00A0 Results\u00C2\u00A0 Initial\u00C2\u00A087Sr/86Sr\u00C2\u00A0(87Sr/86Sr\u00CE\u00AF)\u00C2\u00A0and\u00C2\u00A0initial\u00C2\u00A0 143Nd/144Nd\u00C2\u00A0(143Nd/144Nd\u00CE\u00AF)\u00C2\u00A0isotopic\u00C2\u00A0ratios,\u00C2\u00A0as\u00C2\u00A0well\u00C2\u00A0as\u00C2\u00A0 initial\u00C2\u00A0\u00CE\u00B5Nd\u00C2\u00A0(\u00CE\u00B5Nd\u00CE\u00AF)\u00C2\u00A0for\u00C2\u00A0whole\u00C2\u00A0rock\u00C2\u00A0samples\u00C2\u00A0have\u00C2\u00A0been\u00C2\u00A0calculated\u00C2\u00A0to\u00C2\u00A0100\u00C2\u00A0Ma,\u00C2\u00A0the\u00C2\u00A0approximate\u00C2\u00A0age\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0this\u00C2\u00A0study\u00C2\u00A0(Chapter\u00C2\u00A02).\u00C2\u00A0\u00C2\u00A0143Nd/144Nd\u00CE\u00AF\u00C2\u00A0and\u00C2\u00A0\u00CE\u00B5Nd\u00CE\u00AF\u00C2\u00A0were\u00C2\u00A0calculated\u00C2\u00A0using\u00C2\u00A0the\u00C2\u00A0 present\u00C2\u00A0day\u00C2\u00A0values\u00C2\u00A0of\u00C2\u00A0143Nd/144Nd\u00C2\u00A0=\u00C2\u00A00.5123638\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0chondrite\u00E2\u0080\u0090uniform\u00C2\u00A0reservoir\u00C2\u00A0(CHUR)\u00C2\u00A0 (Hamilton\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01983),\u00C2\u00A0147Sm/144Nd\u00C2\u00A0=\u00C2\u00A0(Sm/Nd)*0.602\u00C2\u00A0and\u00C2\u00A0a\u00C2\u00A0decay\u00C2\u00A0constant\u00C2\u00A0\u00CE\u00BB\u00C2\u00A0of\u00C2\u00A06.54\u00C2\u00A0x\u00C2\u00A010\u00E2\u0080\u009012yr\u00E2\u0080\u00901\u00C2\u00A0 (Faure\u00C2\u00A0and\u00C2\u00A0Mensing,\u00C2\u00A02005).\u00C2\u00A0\u00C2\u00A087Sr/86Sr\u00CE\u00AF\u00C2\u00A0was\u00C2\u00A0determined\u00C2\u00A0using\u00C2\u00A0a\u00C2\u00A0 87Rb/86Sr\u00C2\u00A0ratio\u00C2\u00A0=\u00C2\u00A0(Rb/Sr)*2.8935\u00C2\u00A0 (Faure\u00C2\u00A0and\u00C2\u00A0Mensing,\u00C2\u00A02005)\u00C2\u00A0and\u00C2\u00A0a\u00C2\u00A0decay\u00C2\u00A0constant\u00C2\u00A0\u00CE\u00BB\u00C2\u00A0of\u00C2\u00A01.42\u00C2\u00A0x\u00C2\u00A010\u00E2\u0080\u009011yr\u00E2\u0080\u00901.\u00C2\u00A0\u00C2\u00A0208,207,206Pb/204Pb\u00C2\u00A0values\u00C2\u00A0 are\u00C2\u00A0given\u00C2\u00A0as\u00C2\u00A0present\u00C2\u00A0day\u00C2\u00A0measured\u00C2\u00A0values\u00C2\u00A0as\u00C2\u00A0precise\u00C2\u00A0Pb\u00C2\u00A0and\u00C2\u00A0U\u00C2\u00A0concentration\u00C2\u00A0data\u00C2\u00A0are\u00C2\u00A0not\u00C2\u00A0 available\u00C2\u00A0for\u00C2\u00A0these\u00C2\u00A0samples.\u00C2\u00A0\u00C2\u00A0Sr,\u00C2\u00A0Nd,\u00C2\u00A0and\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0data\u00C2\u00A0are\u00C2\u00A0listed\u00C2\u00A0in\u00C2\u00A0tables\u00C2\u00A05.2\u00C2\u00A0and\u00C2\u00A05.3\u00C2\u00A0 5.8.1\u00C2\u00A0 Volcanic\u00C2\u00A0Rocks\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Mafic\u00C2\u00A0and\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0yield\u00C2\u00A0distinctively\u00C2\u00A0different\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0compositions\u00C2\u00A0that\u00C2\u00A0do\u00C2\u00A0 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values\u00C2\u00A0(0.705208\u00E2\u0080\u00900.705235)\u00C2\u00A0than\u00C2\u00A0hanging\u00C2\u00A0wall\u00C2\u00A0basalt\u00C2\u00A0(0.703675\u00E2\u0080\u00900.704276;\u00C2\u00A0Fig\u00C2\u00A05.10A).\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0 \u00E2\u0080\u0098modified\u00E2\u0080\u0099\u00C2\u00A0higher\u00C2\u00A0values\u00C2\u00A0are\u00C2\u00A0slightly\u00C2\u00A0greater\u00C2\u00A0than\u00C2\u00A0the\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rock\u00C2\u00A0Sr\u00C2\u00A0isotope\u00C2\u00A0 compositions.\u00C2\u00A0\u00C2\u00A0Basalt\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0hanging\u00C2\u00A0wall,\u00C2\u00A0which\u00C2\u00A0is\u00C2\u00A0a\u00C2\u00A0better\u00C2\u00A0estimate\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0primary\u00C2\u00A0igneous\u00C2\u00A0 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and\u00C2\u00A0yields\u00C2\u00A0a\u00C2\u00A0narrow\u00C2\u00A0range\u00C2\u00A0of\u00C2\u00A0\u00CE\u00B5Nd\u00CE\u00AF\u00C2\u00A0\u00C2\u00A0(4.73\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A05.93).\u00C2\u00A0Similarly,\u00C2\u00A0Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation\u00C2\u00A0basalt\u00C2\u00A0also\u00C2\u00A0has\u00C2\u00A0 relatively\u00C2\u00A0low\u00C2\u00A0Sm\u00C2\u00A0(1.17\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A02.38\u00C2\u00A0ppm)\u00C2\u00A0and\u00C2\u00A0Nd\u00C2\u00A0(3.38\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A07.23\u00C2\u00A0ppm)\u00C2\u00A0contents\u00C2\u00A0and\u00C2\u00A0a\u00C2\u00A0slightly\u00C2\u00A0broader\u00C2\u00A0 range\u00C2\u00A0of\u00C2\u00A0\u00CE\u00B5Nd\u00CE\u00AF\u00C2\u00A0\u00C2\u00A0(3.82\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A06.83).\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0contrast,\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0have\u00C2\u00A0higher\u00C2\u00A0Sm\u00C2\u00A0and\u00C2\u00A0Nd\u00C2\u00A0contents\u00C2\u00A0 and\u00C2\u00A0somewhat\u00C2\u00A0lower\u00C2\u00A0\u00CE\u00B5Nd\u00CE\u00AF\u00C2\u00A0values.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0Syn\u00E2\u0080\u0090mineralization\u00C2\u00A0rhyolite\u00C2\u00A0has\u00C2\u00A0the\u00C2\u00A0highest\u00C2\u00A0Sm\u00C2\u00A0and\u00C2\u00A0Nd\u00C2\u00A0 Chapter\u00C2\u00A05\u00C2\u00A0 Page\u00C2\u00A0157\u00C2\u00A0 \u00C2\u00A0 contents\u00C2\u00A0(5.76\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A06.72\u00C2\u00A0ppm\u00C2\u00A0and\u00C2\u00A018.72\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A022.93\u00C2\u00A0ppm,\u00C2\u00A0respectively)\u00C2\u00A0and\u00C2\u00A0\u00CE\u00B5Nd\u00CE\u00AF\u00C2\u00A0values\u00C2\u00A0(4.40\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A05.59)\u00C2\u00A0that\u00C2\u00A0 overlap\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0\u00C2\u00A0mafic\u00C2\u00A0volcanic\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0However,\u00C2\u00A0both\u00C2\u00A0post\u00E2\u0080\u0090mineralization\u00C2\u00A0dacite\u00C2\u00A0(Sm\u00C2\u00A0=\u00C2\u00A04.30\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0 4.32,\u00C2\u00A0Nd\u00C2\u00A0=\u00C2\u00A016.08\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A016.62,\u00C2\u00A0\u00CE\u00B5Nd\u00CE\u00AF\u00C2\u00A0=\u00C2\u00A03.01)\u00C2\u00A0and\u00C2\u00A0rhyolite\u00C2\u00A0dykes\u00C2\u00A0(Sm\u00C2\u00A0=\u00C2\u00A04.01\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A05.28,\u00C2\u00A0Nd\u00C2\u00A0=\u00C2\u00A016.85\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A021.45,\u00C2\u00A0 \u00CE\u00B5Nd\u00CE\u00AF\u00C2\u00A0=1.85\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A01.95)\u00C2\u00A0yield\u00C2\u00A0distinctly\u00C2\u00A0more\u00C2\u00A0evolved\u00C2\u00A0Nd\u00C2\u00A0isotopic\u00C2\u00A0signatures.\u00C2\u00A0 In\u00C2\u00A0summary,\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0display\u00C2\u00A0a\u00C2\u00A0broad\u00C2\u00A0range\u00C2\u00A0of\u00C2\u00A0positive\u00C2\u00A0\u00CE\u00B5Nd\u00CE\u00AF\u00C2\u00A0values\u00C2\u00A0(1.85\u00C2\u00A0to\u00C2\u00A05.93)\u00C2\u00A0 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close\u00C2\u00A0to\u00C2\u00A0bulk\u00E2\u0080\u0090earth.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0Sr\u00E2\u0080\u0090Nd\u00C2\u00A0isotope\u00C2\u00A0space\u00C2\u00A0all\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0from\u00C2\u00A0this\u00C2\u00A0study\u00C2\u00A0lie\u00C2\u00A0above\u00C2\u00A0the\u00C2\u00A0 mantle\u00C2\u00A0array\u00C2\u00A0and\u00C2\u00A0are\u00C2\u00A0more\u00C2\u00A0enriched\u00C2\u00A0than\u00C2\u00A0Mesozoic\u00C2\u00A0or\u00C2\u00A0present\u00E2\u0080\u0090day\u00C2\u00A0Pacific\u00C2\u00A0MORB,\u00C2\u00A0trending\u00C2\u00A0 towards\u00C2\u00A0the\u00C2\u00A0highly\u00C2\u00A0enriched\u00C2\u00A0fields\u00C2\u00A0for\u00C2\u00A0crustal\u00C2\u00A0rocks\u00C2\u00A0(Fig.\u00C2\u00A05.11A).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0lead\u00C2\u00A0isotope\u00C2\u00A0systematics\u00C2\u00A0 reflect\u00C2\u00A0the\u00C2\u00A0crustal\u00C2\u00A0component\u00C2\u00A0more\u00C2\u00A0effectively\u00C2\u00A0as\u00C2\u00A0all\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0study\u00C2\u00A0are\u00C2\u00A0 characterized\u00C2\u00A0by\u00C2\u00A0high\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0ratios.\u00C2\u00A0 5.8.2\u00C2\u00A0 Massive\u00C2\u00A0Sulphide\u00C2\u00A0Deposits\u00C2\u00A0 Six\u00C2\u00A0galena\u00C2\u00A0and\u00C2\u00A0pyrite\u00C2\u00A0mineral\u00C2\u00A0separates\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0TG1,\u00C2\u00A0TG3\u00C2\u00A0and\u00C2\u00A0B5\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0 yield\u00C2\u00A0a\u00C2\u00A0narrow\u00C2\u00A0range\u00C2\u00A0of\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0ratios\u00C2\u00A0(206Pb/204Pb\u00C2\u00A0=\u00C2\u00A018.87\u00E2\u0080\u009018.93)\u00C2\u00A0that\u00C2\u00A0partly\u00C2\u00A0overlap\u00C2\u00A0when\u00C2\u00A0 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higher\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0ratios\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0syn\u00E2\u0080\u0090mineralization\u00C2\u00A0rhyolite,\u00C2\u00A0Th/Yb\u00C2\u00A0and\u00C2\u00A0\u00CE\u00B5Nd\u00C2\u00A0values\u00C2\u00A0broadly\u00C2\u00A0 overlap\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0basalt\u00C2\u00A0data.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0contrast,\u00C2\u00A0post\u00E2\u0080\u0090mineralization\u00C2\u00A0dacite\u00C2\u00A0flows\u00C2\u00A0and\u00C2\u00A0rhyolite\u00C2\u00A0dykes\u00C2\u00A0 Chapter\u00C2\u00A05\u00C2\u00A0 Page\u00C2\u00A0160\u00C2\u00A0 \u00C2\u00A0 are\u00C2\u00A0clearly\u00C2\u00A0distinguished\u00C2\u00A0by\u00C2\u00A0lower\u00C2\u00A0\u00CE\u00B5Nd\u00C2\u00A0values\u00C2\u00A0and\u00C2\u00A0higher\u00C2\u00A0Th/Yb\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0greater\u00C2\u00A0crustal\u00C2\u00A0 assimilation\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0parent\u00C2\u00A0magmas.\u00C2\u00A0\u00C2\u00A0Further\u00C2\u00A0direct\u00C2\u00A0evidence\u00C2\u00A0for\u00C2\u00A0crustal\u00C2\u00A0contamination\u00C2\u00A0includes\u00C2\u00A0 minor\u00C2\u00A0inheritance\u00C2\u00A0of\u00C2\u00A0older\u00C2\u00A0zircons\u00C2\u00A0in\u00C2\u00A0some\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0(Chapter\u00C2\u00A02).\u00C2\u00A0 Granites\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0Coastal\u00C2\u00A0Batholith\u00C2\u00A0are\u00C2\u00A0much\u00C2\u00A0less\u00C2\u00A0radiogenic\u00C2\u00A0than\u00C2\u00A0older\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0 but\u00C2\u00A0are\u00C2\u00A0isotopically\u00C2\u00A0similar\u00C2\u00A0to\u00C2\u00A0basalt.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0granitoids\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0coastal\u00C2\u00A0region\u00C2\u00A0(Western\u00C2\u00A0Cordillera)\u00C2\u00A0 are\u00C2\u00A0voluminous\u00C2\u00A0and\u00C2\u00A0yield\u00C2\u00A0isotopic\u00C2\u00A0compositions\u00C2\u00A0that\u00C2\u00A0suggest\u00C2\u00A0there\u00C2\u00A0was\u00C2\u00A0little\u00C2\u00A0influence\u00C2\u00A0from\u00C2\u00A0 radiogenic\u00C2\u00A0old\u00C2\u00A0crust\u00C2\u00A0(Soler\u00C2\u00A0and\u00C2\u00A0Rotach\u00E2\u0080\u0090Toulhoat,\u00C2\u00A01990).\u00C2\u00A0\u00C2\u00A0Further,\u00C2\u00A0Eastern\u00C2\u00A0Cordillera\u00C2\u00A0batholiths\u00C2\u00A0 contain\u00C2\u00A0little\u00C2\u00A0evidence\u00C2\u00A0from\u00C2\u00A0contamination\u00C2\u00A0of\u00C2\u00A0old\u00C2\u00A0continental\u00C2\u00A0crust,\u00C2\u00A0despite\u00C2\u00A0traversing\u00C2\u00A0 basement\u00C2\u00A0rocks\u00C2\u00A0up\u00C2\u00A0to\u00C2\u00A0>50\u00C2\u00A0km\u00C2\u00A0thick\u00C2\u00A0(Petford\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01996).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0isotopic\u00C2\u00A0data\u00C2\u00A0presented\u00C2\u00A0here\u00C2\u00A0 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as\u00C2\u00A0well\u00C2\u00A0their\u00C2\u00A0respective\u00C2\u00A0Pb\u00C2\u00A0contents,\u00C2\u00A0it\u00C2\u00A0is\u00C2\u00A0possible\u00C2\u00A0to\u00C2\u00A0estimate\u00C2\u00A0the\u00C2\u00A0relative\u00C2\u00A0Pb\u00C2\u00A0contributions\u00C2\u00A0of\u00C2\u00A0 each\u00C2\u00A0of\u00C2\u00A0these\u00C2\u00A0volcanic\u00C2\u00A0rock\u00C2\u00A0units\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0VMS\u00C2\u00A0deposits.\u00C2\u00A0\u00C2\u00A0Based\u00C2\u00A0on\u00C2\u00A0average\u00C2\u00A0206Pb/204Pb\u00C2\u00A0ratios\u00C2\u00A0for\u00C2\u00A0 basalt\u00C2\u00A0=\u00C2\u00A018.80,\u00C2\u00A0rhyolite\u00C2\u00A0=\u00C2\u00A019.95,\u00C2\u00A0and\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0minerals\u00C2\u00A0=\u00C2\u00A018.90,\u00C2\u00A0as\u00C2\u00A0well\u00C2\u00A0as\u00C2\u00A0an\u00C2\u00A0 approximate\u00C2\u00A0Pb\u00C2\u00A0content\u00C2\u00A0for\u00C2\u00A0rhyolite\u00C2\u00A0that\u00C2\u00A0is\u00C2\u00A0nominally\u00C2\u00A02.5\u00C2\u00A0times\u00C2\u00A0greater\u00C2\u00A0than\u00C2\u00A0basalt\u00C2\u00A0(rhyolite\u00C2\u00A0\u00E2\u0089\u0088\u00C2\u00A05\u00C2\u00A0 ppm,\u00C2\u00A0basalt\u00C2\u00A0<\u00C2\u00A02\u00C2\u00A0ppm),\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0Pb\u00C2\u00A0contributions\u00C2\u00A0are\u00C2\u00A03%\u00C2\u00A0for\u00C2\u00A0rhyolite\u00C2\u00A0and\u00C2\u00A097%\u00C2\u00A0for\u00C2\u00A0basalt.\u00C2\u00A0\u00C2\u00A0 This\u00C2\u00A0is\u00C2\u00A0consistent\u00C2\u00A0with\u00C2\u00A0field\u00C2\u00A0observations\u00C2\u00A0which\u00C2\u00A0suggest\u00C2\u00A0an\u00C2\u00A0almost\u00C2\u00A0wholly\u00C2\u00A0mafic\u00C2\u00A0footwall\u00C2\u00A0 sequence\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation.\u00C2\u00A0\u00C2\u00A0Therefore,\u00C2\u00A0despite\u00C2\u00A0an\u00C2\u00A0intimate\u00C2\u00A0spatial\u00C2\u00A0and\u00C2\u00A0 temporal\u00C2\u00A0association,\u00C2\u00A0contemporaneous\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0apparently\u00C2\u00A0provided\u00C2\u00A0a\u00C2\u00A0negligible\u00C2\u00A0 contribution\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0Pb\u00C2\u00A0metal\u00C2\u00A0budget\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0at\u00C2\u00A0Tambogrande.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0proportion\u00C2\u00A0of\u00C2\u00A0 other\u00C2\u00A0metals\u00C2\u00A0(copper,\u00C2\u00A0zinc,\u00C2\u00A0gold)\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0mafic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0is\u00C2\u00A0perhaps\u00C2\u00A0even\u00C2\u00A0higher\u00C2\u00A0 considering\u00C2\u00A0the\u00C2\u00A0abundance\u00C2\u00A0of\u00C2\u00A0these\u00C2\u00A0metals\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0mafic\u00C2\u00A0rocks\u00C2\u00A0in\u00C2\u00A0comparison\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0felsic\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0data\u00C2\u00A0suggest\u00C2\u00A0that\u00C2\u00A0the\u00C2\u00A0bulk\u00C2\u00A0of\u00C2\u00A0metals\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0Tambogrande\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0were\u00C2\u00A0derived\u00C2\u00A0via\u00C2\u00A0 hydrothermal\u00C2\u00A0leaching\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0underlying\u00C2\u00A0mafic\u00C2\u00A0volcanic\u00C2\u00A0strata\u00C2\u00A0and/or\u00C2\u00A0from\u00C2\u00A0a\u00C2\u00A0magmatic\u00C2\u00A0volatile\u00C2\u00A0 phase\u00C2\u00A0from\u00C2\u00A0mafic\u00C2\u00A0subvolcanic\u00C2\u00A0intrusions\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0same\u00C2\u00A0isotopic\u00C2\u00A0character.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 5.9.2\u00C2\u00A0 Possible\u00C2\u00A0Linkages\u00C2\u00A0Between\u00C2\u00A0Petrogenesis\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Felsic\u00C2\u00A0Volcanic\u00C2\u00A0Suite\u00C2\u00A0and\u00C2\u00A0VMS\u00C2\u00A0 Formation\u00C2\u00A0\u00C2\u00A0 Current\u00C2\u00A0VMS\u00C2\u00A0genetic\u00C2\u00A0models\u00C2\u00A0suggest\u00C2\u00A0a\u00C2\u00A0link\u00C2\u00A0between\u00C2\u00A0the\u00C2\u00A0nature\u00C2\u00A0and\u00C2\u00A0extent\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0 hydrothermal\u00C2\u00A0circulation\u00C2\u00A0systems\u00C2\u00A0and\u00C2\u00A0contemporaneous\u00C2\u00A0igneous\u00C2\u00A0rocks\u00C2\u00A0(Lydon,\u00C2\u00A01988;\u00C2\u00A0Franklin,\u00C2\u00A0 1995;\u00C2\u00A0Franklin\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02005;\u00C2\u00A0Galley,\u00C2\u00A01993).\u00C2\u00A0\u00C2\u00A0All\u00C2\u00A0VMS\u00C2\u00A0genetic\u00C2\u00A0models\u00C2\u00A0require\u00C2\u00A0a\u00C2\u00A0thermal\u00C2\u00A0source\u00C2\u00A0to\u00C2\u00A0 drive\u00C2\u00A0the\u00C2\u00A0hydrothermal\u00C2\u00A0convective\u00C2\u00A0system\u00C2\u00A0(and\u00C2\u00A0possibly\u00C2\u00A0contribute\u00C2\u00A0metals),\u00C2\u00A0that\u00C2\u00A0is\u00C2\u00A0generally\u00C2\u00A0 Chapter\u00C2\u00A05\u00C2\u00A0 Page\u00C2\u00A0163\u00C2\u00A0 \u00C2\u00A0 considered\u00C2\u00A0to\u00C2\u00A0be\u00C2\u00A0new\u00C2\u00A0magma\u00C2\u00A0input\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0upper\u00C2\u00A0crust.\u00C2\u00A0\u00C2\u00A0Heat\u00E2\u0080\u0090\u00C2\u00A0and\u00C2\u00A0fluid\u00E2\u0080\u0090flow\u00C2\u00A0modeling\u00C2\u00A0indicates\u00C2\u00A0 that\u00C2\u00A0substantial\u00C2\u00A0thermal\u00C2\u00A0input\u00C2\u00A0into\u00C2\u00A0the\u00C2\u00A0upper\u00C2\u00A0crust\u00C2\u00A0is\u00C2\u00A0required\u00C2\u00A0in\u00C2\u00A0order\u00C2\u00A0to\u00C2\u00A0sustain\u00C2\u00A0a\u00C2\u00A0 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component\u00C2\u00A0is\u00C2\u00A0either\u00C2\u00A0a\u00C2\u00A0primary\u00C2\u00A0melt\u00C2\u00A0equivalent\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0basalt\u00C2\u00A0or\u00C2\u00A0re\u00E2\u0080\u0090melted\u00C2\u00A0juvenile\u00C2\u00A0arc\u00C2\u00A0(mafic)\u00C2\u00A0 crust,\u00C2\u00A0whereas\u00C2\u00A0the\u00C2\u00A0radiogenic\u00C2\u00A0source\u00C2\u00A0is\u00C2\u00A0old\u00C2\u00A0continental\u00C2\u00A0crust\u00C2\u00A0such\u00C2\u00A0as\u00C2\u00A0the\u00C2\u00A0Olmos\u00C2\u00A0Complex\u00C2\u00A0or\u00C2\u00A0 sedimentary\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0similar\u00C2\u00A0provenance.\u00C2\u00A0\u00C2\u00A0Hybridization\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0mafic\u00C2\u00A0magmas\u00C2\u00A0resulted\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0 assimilation\u00C2\u00A0of\u00C2\u00A0continental\u00C2\u00A0crust\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0mid\u00E2\u0080\u0090upper\u00C2\u00A0crustal\u00C2\u00A0column.\u00C2\u00A0\u00C2\u00A0That\u00C2\u00A0these\u00C2\u00A0bimodal\u00C2\u00A0volcanic\u00C2\u00A0 rocks\u00C2\u00A0were\u00C2\u00A0erupted\u00C2\u00A0essentially\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0same\u00C2\u00A0space\u00C2\u00A0and\u00C2\u00A0time\u00C2\u00A0attests\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0complexity\u00C2\u00A0of\u00C2\u00A0VMS\u00E2\u0080\u0090 associated\u00C2\u00A0volcanic\u00C2\u00A0magmas.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0interpretation\u00C2\u00A0is\u00C2\u00A0consistent\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0inferred\u00C2\u00A0geodynamic\u00C2\u00A0 setting\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0continental\u00C2\u00A0margin\u00C2\u00A0volcanic\u00C2\u00A0arc\u00E2\u0080\u0090rift.\u00C2\u00A0 Chapter\u00C2\u00A05\u00C2\u00A0 Page\u00C2\u00A0166\u00C2\u00A0 \u00C2\u00A0 The\u00C2\u00A0uniformity\u00C2\u00A0of\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0compositions\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0TG1,\u00C2\u00A0TG3\u00C2\u00A0and\u00C2\u00A0B5\u00C2\u00A0 deposits\u00C2\u00A0suggests\u00C2\u00A0homogenization\u00C2\u00A0of\u00C2\u00A0Pb\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0VMS\u00E2\u0080\u0090forming\u00C2\u00A0hydrothermal\u00C2\u00A0system.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0 deposits\u00C2\u00A0either\u00C2\u00A0formed\u00C2\u00A0from\u00C2\u00A0a\u00C2\u00A0common\u00C2\u00A0hydrothermal\u00C2\u00A0system\u00C2\u00A0or\u00C2\u00A0derived\u00C2\u00A0metals\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0same\u00C2\u00A0 source\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0Based\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0data,\u00C2\u00A0metal\u00C2\u00A0sources\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0are\u00C2\u00A0dominated\u00C2\u00A0 by\u00C2\u00A0basaltic\u00C2\u00A0footwall\u00C2\u00A0rocks,\u00C2\u00A0whereas\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0contributed\u00C2\u00A0insignificant\u00C2\u00A0amounts\u00C2\u00A0of\u00C2\u00A0 metal.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0is\u00C2\u00A0consistent\u00C2\u00A0with\u00C2\u00A0observations\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0footwall\u00C2\u00A0sequence\u00C2\u00A0composed\u00C2\u00A0nearly\u00C2\u00A0entirely\u00C2\u00A0of\u00C2\u00A0 mafic\u00C2\u00A0volcanic\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0data\u00C2\u00A0occur\u00C2\u00A0along\u00C2\u00A0a\u00C2\u00A0steep\u00C2\u00A0array\u00C2\u00A0on\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0plots,\u00C2\u00A0 indicating\u00C2\u00A0two\u00E2\u0080\u0090component\u00C2\u00A0mixing,\u00C2\u00A0very\u00C2\u00A0similar\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0Province\u00C2\u00A0II\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0field\u00C2\u00A0of\u00C2\u00A0Mcfarlane\u00C2\u00A0 et\u00C2\u00A0al.\u00C2\u00A0(1990).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0least\u00C2\u00A0radiogenic\u00C2\u00A0endmember\u00C2\u00A0is\u00C2\u00A0the\u00C2\u00A0mafic\u00E2\u0080\u0090dominant\u00C2\u00A0volcanic\u00C2\u00A0sequence,\u00C2\u00A0 whereas\u00C2\u00A0the\u00C2\u00A0more\u00C2\u00A0radiogenic\u00C2\u00A0endmember\u00C2\u00A0is\u00C2\u00A0homogenized\u00C2\u00A0lead\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0continental\u00C2\u00A0crust.\u00C2\u00A0\u00C2\u00A0 Genetic\u00C2\u00A0models\u00C2\u00A0for\u00C2\u00A0VMS\u00C2\u00A0formation\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0favour\u00C2\u00A0hydrothermal\u00C2\u00A0leaching\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 footwall\u00C2\u00A0mafic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0(and/or\u00C2\u00A0a\u00C2\u00A0metal\u00C2\u00A0contribution\u00C2\u00A0from\u00C2\u00A0magmatic\u00C2\u00A0devolatilization\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0 mafic\u00C2\u00A0intrusion).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0close\u00C2\u00A0spatial\u00C2\u00A0and\u00C2\u00A0temporal\u00C2\u00A0association\u00C2\u00A0of\u00C2\u00A0felsic\u00C2\u00A0volcanism\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0VMS\u00C2\u00A0 deposits\u00C2\u00A0is\u00C2\u00A0linked\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0thermal\u00C2\u00A0anomaly\u00C2\u00A0generated\u00C2\u00A0at\u00C2\u00A0mid\u00E2\u0080\u0090upper\u00C2\u00A0crustal\u00C2\u00A0levels\u00C2\u00A0by\u00C2\u00A0the\u00C2\u00A0 introduction\u00C2\u00A0of\u00C2\u00A0mafic\u00C2\u00A0magmas\u00C2\u00A0which\u00C2\u00A0likely\u00C2\u00A0underplated\u00C2\u00A0the\u00C2\u00A0upper\u00C2\u00A0crust.\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0magmas,\u00C2\u00A0or\u00C2\u00A0 partial\u00C2\u00A0melts\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0existing\u00C2\u00A0juvenile\u00C2\u00A0arc\u00C2\u00A0crust,\u00C2\u00A0were\u00C2\u00A0subsequently\u00C2\u00A0hybridized\u00C2\u00A0by\u00C2\u00A0older\u00C2\u00A0 continental\u00C2\u00A0crust\u00C2\u00A0and\u00C2\u00A0resulted\u00C2\u00A0in\u00C2\u00A0high\u00E2\u0080\u0090temperature\u00C2\u00A0felsic\u00C2\u00A0magmatism.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0heat\u00C2\u00A0input\u00C2\u00A0into\u00C2\u00A0the\u00C2\u00A0 upper\u00C2\u00A0crust\u00C2\u00A0was\u00C2\u00A0sufficient\u00C2\u00A0to\u00C2\u00A0generate\u00C2\u00A0large\u00E2\u0080\u0090scale\u00C2\u00A0hydrothermal\u00C2\u00A0convective\u00C2\u00A0circulation\u00C2\u00A0that\u00C2\u00A0 resulted\u00C2\u00A0in\u00C2\u00A0deposition\u00C2\u00A0of\u00C2\u00A0massive\u00C2\u00A0sulphides\u00C2\u00A0at\u00C2\u00A0and\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0seafloor.\u00C2\u00A0\u00C2\u00A0Therefore,\u00C2\u00A0the\u00C2\u00A0petrogenesis\u00C2\u00A0 of\u00C2\u00A0the\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0Tambogrande\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0has\u00C2\u00A0no\u00C2\u00A0causal\u00C2\u00A0 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Table\u00C2\u00A05.1.\u00C2\u00A0\u00C2\u00A0Sample\u00C2\u00A0location\u00C2\u00A0data,\u00C2\u00A0approximate\u00C2\u00A0age\u00C2\u00A0and\u00C2\u00A0rock\u00C2\u00A0descriptions.\u00C2\u00A0\u00C2\u00A0All\u00C2\u00A0samples\u00C2\u00A0are\u00C2\u00A0from\u00C2\u00A0diamond\u00C2\u00A0drill\u00C2\u00A0core\u00C2\u00A0except\u00C2\u00A0for\u00C2\u00A0LW002.\u00C2\u00A0\u00C2\u00A0Coordinates\u00C2\u00A0 are\u00C2\u00A0in\u00C2\u00A0map\u00C2\u00A0projection\u00C2\u00A0WGS\u00C2\u00A084,\u00C2\u00A0UTM\u00C2\u00A0Zone\u00C2\u00A017\u00C2\u00A0Southern\u00C2\u00A0Hemisphere.\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Sample\u00C2\u00A0 Easting\u00C2\u00A0 Northing\u00C2\u00A0 Formation\u00C2\u00A0 Lithology\u00C2\u00A0 Age\u00C2\u00A0Ma\u00C2\u00A0 Comments\u00C2\u00A0 LW002\u00C2\u00A0 571930\u00C2\u00A0 9475394\u00C2\u00A0 Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0 basalt\u00C2\u00A0 91\u00E2\u0080\u0090100\u00C2\u00A0 plagioclase\u00C2\u00A0porphyritic\u00C2\u00A0flow\u00C2\u00A0 SU\u00E2\u0080\u00902\u00C2\u00A0169.5\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 549200\u00C2\u00A0 9455650\u00C2\u00A0 Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0 basalt\u00C2\u00A0\u00C2\u00A0 91\u00E2\u0080\u0090100\u00C2\u00A0 plagioclase\u00C2\u00A0porphyritic\u00C2\u00A0flow\u00C2\u00A0 00TG1\u00E2\u0080\u0090219\u00C2\u00A069.5\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 573816\u00C2\u00A0 9454987\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 footwall\u00C2\u00A0basalt\u00C2\u00A0 >104.8\u00C2\u00A0 autobreccia\u00C2\u00A0(clast\u00C2\u00A0sample);\u00C2\u00A0sericite\u00E2\u0080\u0090chlorite\u00C2\u00A0alteration\u00C2\u00A0 99\u00E2\u0080\u0090TG3\u00E2\u0080\u0090048\u00C2\u00A0426.35\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 573612\u00C2\u00A0 9453492\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 footwall\u00C2\u00A0basalt\u00C2\u00A0 >104.8\u00C2\u00A0 basalt\u00C2\u00A0flow;\u00C2\u00A0sericite\u00E2\u0080\u0090chlorite\u00C2\u00A0alteration\u00C2\u00A0 99TG3\u00E2\u0080\u0090006\u00C2\u00A086.5\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 573746\u00C2\u00A0 9453675\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 hanging\u00C2\u00A0wall\u00C2\u00A0basalt\u00C2\u00A0 <\u00C2\u00A0104.8\u00C2\u00A0 feldspar\u00E2\u0080\u0090augite\u00C2\u00A0phyric\u00C2\u00A0flow\u00C2\u00A0 99TG3\u00E2\u0080\u0090030\u00C2\u00A031.75\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 573815\u00C2\u00A0 9453628\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 hanging\u00C2\u00A0wall\u00C2\u00A0basalt\u00C2\u00A0 <\u00C2\u00A0104.8\u00C2\u00A0 feldspar\u00E2\u0080\u0090augite\u00C2\u00A0phyric\u00C2\u00A0flow\u00C2\u00A0 99TG3\u00E2\u0080\u0090023\u00C2\u00A0132.65\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 573823\u00C2\u00A0 9453765\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 hanging\u00C2\u00A0wall\u00C2\u00A0\u00C2\u00A0dacite\u00C2\u00A0 <\u00C2\u00A0104.8\u00C2\u00A0 feldspar\u00C2\u00A0phyric\u00C2\u00A0flow\u00C2\u00A0 99TG3\u00E2\u0080\u0090041\u00C2\u00A0101\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 573823\u00C2\u00A0 9453915\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 hanging\u00C2\u00A0wall\u00C2\u00A0\u00C2\u00A0dacite\u00C2\u00A0 <\u00C2\u00A0104.8\u00C2\u00A0 feldspar\u00C2\u00A0phyric\u00C2\u00A0flow\u00C2\u00A0 00TG1\u00E2\u0080\u0090351\u00C2\u00A0112\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 573691\u00C2\u00A0 9455166\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 rhyolite\u00C2\u00A0dyke\u00C2\u00A0 100.2\u00C2\u00A0 feldspar\u00E2\u0080\u0090quartz\u00C2\u00A0porphyry\u00C2\u00A0dyke\u00C2\u00A0 99TG1\u00E2\u0080\u0090111\u00C2\u00A083.4\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 573696\u00C2\u00A0 9454532\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 rhyolite\u00C2\u00A0dyke\u00C2\u00A0 100.2\u00C2\u00A0 feldspar\u00E2\u0080\u0090quartz\u00C2\u00A0porphyry\u00C2\u00A0dyke\u00C2\u00A0 99TG3\u00E2\u0080\u0090019\u00C2\u00A0365.5\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 573434\u00C2\u00A0 9453030\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 syn\u00E2\u0080\u0090mineralization\u00C2\u00A0rhyolite\u00C2\u00A0 104.8\u00C2\u00A0 aphyric\u00C2\u00A0flow\u00C2\u00A0 99\u00E2\u0080\u0090TG3\u00E2\u0080\u0090048\u00C2\u00A0337.5\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 573612\u00C2\u00A0 9453492\u00C2\u00A0 Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 syn\u00E2\u0080\u0090mineralization\u00C2\u00A0rhyolite\u00C2\u00A0 104.8\u00C2\u00A0 aphyric\u00C2\u00A0flow\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A05\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A0184\u00C2\u00A0 \u00C2\u00A0 Table\u00C2\u00A05.2.\u00C2\u00A0\u00C2\u00A0Pb,\u00C2\u00A0Nd\u00C2\u00A0and\u00C2\u00A0Sr\u00C2\u00A0isotope\u00C2\u00A0data\u00C2\u00A0from\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0at\u00C2\u00A0Tambogrande.\u00C2\u00A0\u00C2\u00A0\u00E2\u0080\u0098Initial\u00E2\u0080\u0099\u00C2\u00A0isotope\u00C2\u00A0values\u00C2\u00A0are\u00C2\u00A0calculated\u00C2\u00A0to\u00C2\u00A0 100\u00C2\u00A0Ma.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Sample\u00C2\u00A0 Pb\u00C2\u00A0 ppm\u00C2\u00A0 U\u00C2\u00A0 ppm\u00C2\u00A0 Th\u00C2\u00A0 ppm\u00C2\u00A0 206Pb/204Pb\u00C2\u00A0 207Pb/204Pb\u00C2\u00A0 208Pb/204Pb\u00C2\u00A0 Sm\u00C2\u00A0 ppm\u00C2\u00A0 Nd\u00C2\u00A0 ppm\u00C2\u00A0 143Nd/144Nd\u00C2\u00A0 \u00CE\u00B5Nd\u00CE\u00AF\u00C2\u00A0 Rb\u00C2\u00A0 ppm\u00C2\u00A0 Sr\u00C2\u00A0 ppm\u00C2\u00A0 87Sr/86Sr\u00C2\u00A0 87Sr/86Sr\u00CE\u00AF LW002\u00C2\u00A0 5\u00C2\u00A0 <0.5\u00C2\u00A0 0.33\u00C2\u00A0 19.0147\u00C2\u00A0 15.6985\u00C2\u00A0 38.9072\u00C2\u00A0 1.17\u00C2\u00A0 3.38\u00C2\u00A0 0.512841\u00C2\u00A0 3.82\u00C2\u00A0 3\u00C2\u00A0 190\u00C2\u00A0 0.705667\u00C2\u00A0 0.705602 SU\u00E2\u0080\u00902\u00C2\u00A0169.5\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 <2\u00C2\u00A0 n/a\u00C2\u00A0 0.22\u00C2\u00A0 18.8013\u00C2\u00A0 15.6518\u00C2\u00A0 38.6763\u00C2\u00A0 2.38\u00C2\u00A0 7.23\u00C2\u00A0 0.512989\u00C2\u00A0 6.83\u00C2\u00A0 15\u00C2\u00A0 234\u00C2\u00A0 0.704872\u00C2\u00A0 0.704608 00TG1\u00E2\u0080\u0090219\u00C2\u00A069.5\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 <2\u00C2\u00A0 n/a\u00C2\u00A0 0.25\u00C2\u00A0 18.9723\u00C2\u00A0 15.6835\u00C2\u00A0 38.7822\u00C2\u00A0 1.22\u00C2\u00A0 3.26\u00C2\u00A0 0.512961\u00C2\u00A0 5.93\u00C2\u00A0 17\u00C2\u00A0 111\u00C2\u00A0 0.705865\u00C2\u00A0 0.705235 99\u00E2\u0080\u0090TG3\u00E2\u0080\u0090048\u00C2\u00A0426.35\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 3\u00C2\u00A0 n/a\u00C2\u00A0 0.65\u00C2\u00A0 19.0173\u00C2\u00A0 15.6861\u00C2\u00A0 38.8287\u00C2\u00A0 2.08\u00C2\u00A0 6.04\u00C2\u00A0 0.512899\u00C2\u00A0 4.95\u00C2\u00A0 7\u00C2\u00A0 150\u00C2\u00A0 0.705400\u00C2\u00A0 0.705208 99TG3\u00E2\u0080\u0090006\u00C2\u00A086.5\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 <2\u00C2\u00A0 n/a\u00C2\u00A0 1.04\u00C2\u00A0 19.3685\u00C2\u00A0 15.6860\u00C2\u00A0 38.8556\u00C2\u00A0 2.54\u00C2\u00A0 8.68\u00C2\u00A0 0.512867\u00C2\u00A0 4.73\u00C2\u00A0 11\u00C2\u00A0 483\u00C2\u00A0 0.704370\u00C2\u00A0 0.704276 99TG3\u00E2\u0080\u0090030\u00C2\u00A031.75\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 <2\u00C2\u00A0 n/a\u00C2\u00A0 0.89\u00C2\u00A0 18.9365\u00C2\u00A0 15.6608\u00C2\u00A0 38.6997\u00C2\u00A0 2.61\u00C2\u00A0 9.52\u00C2\u00A0 0.512903\u00C2\u00A0 5.57\u00C2\u00A0 33\u00C2\u00A0 350\u00C2\u00A0 0.704063\u00C2\u00A0 0.703675 99TG3\u00E2\u0080\u0090023\u00C2\u00A0132.65\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 <2\u00C2\u00A0 n/a\u00C2\u00A0 4.12\u00C2\u00A0 19.6574\u00C2\u00A0 15.7143\u00C2\u00A0 39.4066\u00C2\u00A0 4.30\u00C2\u00A0 16.08\u00C2\u00A0 0.512769\u00C2\u00A0 3.01\u00C2\u00A0 20\u00C2\u00A0 61\u00C2\u00A0 0.705722\u00C2\u00A0 0.704374 99TG3\u00E2\u0080\u0090041\u00C2\u00A0101\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 <2\u00C2\u00A0 n/a\u00C2\u00A0 4.66\u00C2\u00A0 20.3492\u00C2\u00A0 15.7463\u00C2\u00A0 39.7863\u00C2\u00A0 4.32\u00C2\u00A0 16.62\u00C2\u00A0 0.512766\u00C2\u00A0 3.01\u00C2\u00A0 9\u00C2\u00A0 94\u00C2\u00A0 0.705254\u00C2\u00A0 0.704860 00TG1\u00E2\u0080\u0090351\u00C2\u00A0112\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 <2\u00C2\u00A0 n/a\u00C2\u00A0 8.96\u00C2\u00A0 19.8028\u00C2\u00A0 15.7158\u00C2\u00A0 39.6656\u00C2\u00A0 5.28\u00C2\u00A0 21.45\u00C2\u00A0 0.512706\u00C2\u00A0 1.95\u00C2\u00A0 13\u00C2\u00A0 143\u00C2\u00A0 0.705437\u00C2\u00A0 0.705063 99TG1\u00E2\u0080\u0090111\u00C2\u00A083.4\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 <2\u00C2\u00A0 n/a\u00C2\u00A0 8.27\u00C2\u00A0 19.6391\u00C2\u00A0 15.7056\u00C2\u00A0 39.4937\u00C2\u00A0 4.01\u00C2\u00A0 16.85\u00C2\u00A0 0.512698\u00C2\u00A0 1.85\u00C2\u00A0 26\u00C2\u00A0 117\u00C2\u00A0 0.705501\u00C2\u00A0 0.704587 99TG3\u00E2\u0080\u0090019\u00C2\u00A0365.5\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 <2\u00C2\u00A0 n/a\u00C2\u00A0 4.17\u00C2\u00A0 20.0273\u00C2\u00A0 15.7333\u00C2\u00A0 39.7836\u00C2\u00A0 6.72\u00C2\u00A0 22.93\u00C2\u00A0 0.512850\u00C2\u00A0 4.40\u00C2\u00A0 11\u00C2\u00A0 57\u00C2\u00A0 0.705621\u00C2\u00A0 0.704828 99\u00E2\u0080\u0090TG3\u00E2\u0080\u0090048\u00C2\u00A0337.5\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 <2\u00C2\u00A0 n/a\u00C2\u00A0 3.21\u00C2\u00A0 20.1869\u00C2\u00A0 15.7380\u00C2\u00A0 39.4124\u00C2\u00A0 5.76\u00C2\u00A0 18.72\u00C2\u00A0 0.512917\u00C2\u00A0 5.59\u00C2\u00A0 3\u00C2\u00A0 60\u00C2\u00A0 0.704778\u00C2\u00A0 0.704572 \u00C2\u00A0 n/a\u00C2\u00A0=\u00C2\u00A0not\u00C2\u00A0analyzed\u00C2\u00A0 Chapter\u00C2\u00A05\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A0185\u00C2\u00A0 \u00C2\u00A0 Chapter\u00C2\u00A05\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A0186\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Table\u00C2\u00A05.3.\u00C2\u00A0\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0compositions\u00C2\u00A0of\u00C2\u00A0Tambogrande\u00C2\u00A0ore\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0post\u00E2\u0080\u0090mineralization\u00C2\u00A0intrusive\u00C2\u00A0phases\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin.\u00C2\u00A0 \u00C2\u00A0 Sample\u00C2\u00A0 Easting\u00C2\u00A0 Northing\u00C2\u00A0 rock\u00C2\u00A0type\u00C2\u00A0 Age\u00C2\u00A0 Ma\u00C2\u00A0 Mineral\u00C2\u00A0 206Pb/204Pb\u00C2\u00A0 207Pb/204Pb\u00C2\u00A0 208Pb/204Pb\u00C2\u00A0 B5\u00C2\u00A0005\u00E2\u0080\u0090542\u00C2\u00A0 569883\u00C2\u00A0 9442360\u00C2\u00A0 massive\u00C2\u00A0sulphide\u00C2\u00A0 ~104\u00C2\u00A0 galena\u00C2\u00A0 18.8747\u00C2\u00A0 15.6942\u00C2\u00A0 38.7636\u00C2\u00A0 TG1\u00C2\u00A0028\u00C2\u00A020.4\u00C2\u00A0 573638\u00C2\u00A0 9454725\u00C2\u00A0 massive\u00C2\u00A0sulphide\u00C2\u00A0 ~104\u00C2\u00A0 pyrite\u00C2\u00A0 18.9211\u00C2\u00A0 15.6951\u00C2\u00A0 38.8118\u00C2\u00A0 TG1\u00C2\u00A0237\u00E2\u0080\u009079.2\u00C2\u00A0 573460\u00C2\u00A0 9455147\u00C2\u00A0 massive\u00C2\u00A0sulphide\u00C2\u00A0 ~104\u00C2\u00A0 galena\u00C2\u00A0 18.9126\u00C2\u00A0 15.6890\u00C2\u00A0 38.7835\u00C2\u00A0 TG1\u00C2\u00A0352\u00E2\u0080\u009094.5\u00C2\u00A0 573455\u00C2\u00A0 9455227\u00C2\u00A0 massive\u00C2\u00A0sulphide\u00C2\u00A0 ~104\u00C2\u00A0 galena\u00C2\u00A0 18.8928\u00C2\u00A0 15.6726\u00C2\u00A0 38.7227\u00C2\u00A0 TG3\u00C2\u00A0009\u00E2\u0080\u0090216\u00C2\u00A0 573357\u00C2\u00A0 9453138\u00C2\u00A0 massive\u00C2\u00A0sulphide\u00C2\u00A0 ~104\u00C2\u00A0 galena\u00C2\u00A0 18.8850\u00C2\u00A0 15.6726\u00C2\u00A0 38.7069\u00C2\u00A0 TG3\u00E2\u0080\u0090037\u00E2\u0080\u0090217\u00C2\u00A0 573822\u00C2\u00A0 9453844\u00C2\u00A0 massive\u00C2\u00A0sulphide\u00C2\u00A0 ~104\u00C2\u00A0 galena\u00C2\u00A0 18.9325\u00C2\u00A0 15.7025\u00C2\u00A0 38.8548\u00C2\u00A0 LW\u00E2\u0080\u009031\u00C2\u00A0 484306\u00C2\u00A0 9426178\u00C2\u00A0 Muscovite\u00E2\u0080\u0090bearing\u00C2\u00A0granodiorite,\u00C2\u00A0 Amotape\u00C2\u00A0Terrane.\u00C2\u00A0 ~230\u00C2\u00A0 plagioclase\u00C2\u00A0 18.5962\u00C2\u00A0 15.6682\u00C2\u00A0 38.5807\u00C2\u00A0 LW\u00E2\u0080\u009006\u00C2\u00A0 559404\u00C2\u00A0 9481200\u00C2\u00A0 Las\u00C2\u00A0Lomas\u00C2\u00A0batholith;\u00C2\u00A0hornblende\u00C2\u00A0 granodiorite\u00C2\u00A0 ~47\u00C2\u00A0 plagioclase\u00C2\u00A0 18.7234\u00C2\u00A0 15.6565\u00C2\u00A0 38.6497\u00C2\u00A0 LW\u00E2\u0080\u009036\u00C2\u00A0 567854\u00C2\u00A0 9479640\u00C2\u00A0 Las\u00C2\u00A0Lomas\u00C2\u00A0batholith;\u00C2\u00A0hornblende\u00C2\u00A0 granodiorite\u00C2\u00A0porphyry\u00C2\u00A0 ~52\u00C2\u00A0 plagioclase\u00C2\u00A0 18.7142\u00C2\u00A0 15.6577\u00C2\u00A0 38.6888\u00C2\u00A0 LW\u00E2\u0080\u009085\u00C2\u00A0 581496\u00C2\u00A0 9485511\u00C2\u00A0 Las\u00C2\u00A0Lomas\u00C2\u00A0batholith;\u00C2\u00A0hornblende\u00C2\u00A0granite\u00C2\u00A0 ~80\u00C2\u00A0 plagioclase\u00C2\u00A0 18.9158\u00C2\u00A0 15.6638\u00C2\u00A0 38.9134\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0 5.11\u00C2\u00A0 References\u00C2\u00A0 Aspden,\u00C2\u00A0J.\u00C2\u00A0A.,\u00C2\u00A0Bonilla,W.,\u00C2\u00A0and\u00C2\u00A0Duque,\u00C2\u00A0P.\u00C2\u00A0\u00C2\u00A01995.\u00C2\u00A0The\u00C2\u00A0El\u00C2\u00A0Oro\u00C2\u00A0metamorphic\u00C2\u00A0complex,\u00C2\u00A0Ecuador:\u00C2\u00A0Geology\u00C2\u00A0 and\u00C2\u00A0economic\u00C2\u00A0mineral\u00C2\u00A0deposits.\u00C2\u00A0Overseas\u00C2\u00A0Geology\u00C2\u00A0and\u00C2\u00A0Mineral\u00C2\u00A0Resources,\u00C2\u00A0no.\u00C2\u00A067,\u00C2\u00A063\u00C2\u00A0p.\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Atherton,\u00C2\u00A0M.P.,\u00C2\u00A0Pitcher,\u00C2\u00A0W.S.,\u00C2\u00A0Warden,\u00C2\u00A0V.\u00C2\u00A0\u00C2\u00A01983.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0Mesozoic\u00C2\u00A0marginal\u00C2\u00A0basin\u00C2\u00A0of\u00C2\u00A0central\u00C2\u00A0Per\u00C3\u00BA.\u00C2\u00A0\u00C2\u00A0 Nature,\u00C2\u00A0350:\u00C2\u00A0303\u00E2\u0080\u0090306.\u00C2\u00A0 \u00C2\u00A0 Arculus,\u00C2\u00A0R.J.,\u00C2\u00A0Lapierre,\u00C2\u00A0H.,\u00C2\u00A0and\u00C2\u00A0Jaillard,\u00C2\u00A0E.\u00C2\u00A0\u00C2\u00A01999.\u00C2\u00A0\u00C2\u00A0Geochemical\u00C2\u00A0window\u00C2\u00A0into\u00C2\u00A0subduction\u00C2\u00A0and\u00C2\u00A0accretion\u00C2\u00A0 processes;\u00C2\u00A0Raspas\u00C2\u00A0metamorphic\u00C2\u00A0complex,\u00C2\u00A0Ecuador.\u00C2\u00A0Geology,\u00C2\u00A027:\u00C2\u00A0547\u00E2\u0080\u0090550.\u00C2\u00A0 \u00C2\u00A0 Barrie,\u00C2\u00A0C.T.\u00C2\u00A0and\u00C2\u00A0Hannington,\u00C2\u00A0M.D.\u00C2\u00A0\u00C2\u00A01999.\u00C2\u00A0\u00C2\u00A0Classification\u00C2\u00A0of\u00C2\u00A0volcanic\u00E2\u0080\u0090associated\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0 deposits\u00C2\u00A0based\u00C2\u00A0on\u00C2\u00A0host\u00E2\u0080\u0090rock\u00C2\u00A0composition.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0Volcanic\u00E2\u0080\u0090associated\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits:\u00C2\u00A0 processes\u00C2\u00A0and\u00C2\u00A0examples\u00C2\u00A0in\u00C2\u00A0modern\u00C2\u00A0and\u00C2\u00A0ancient\u00C2\u00A0settings.\u00C2\u00A0\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0C.T.\u00C2\u00A0Barrie\u00C2\u00A0and\u00C2\u00A0M.D.\u00C2\u00A0 Hannington.\u00C2\u00A0\u00C2\u00A0Reviews\u00C2\u00A0in\u00C2\u00A0Economic\u00C2\u00A0Geology,\u00C2\u00A0Volume\u00C2\u00A08,\u00C2\u00A0pp.\u00C2\u00A01\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A011.\u00C2\u00A0 \u00C2\u00A0 Barrie,\u00C2\u00A0C.T.,\u00C2\u00A0Ludden,\u00C2\u00A0J.N.,\u00C2\u00A0Green,\u00C2\u00A0T.H.,\u00C2\u00A0Spooner,\u00C2\u00A0E.T.C.\u00C2\u00A0\u00C2\u00A01993.\u00C2\u00A0Geochemistry\u00C2\u00A0of\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0 associated\u00C2\u00A0with\u00C2\u00A0Cu\u00E2\u0080\u0090Zn\u00C2\u00A0and\u00C2\u00A0Ni\u00E2\u0080\u0090Cu\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Abitibi\u00C2\u00A0Subprovince,\u00C2\u00A0Economic\u00C2\u00A0Geology\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0 Bulletin\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0Economic\u00C2\u00A0Geologists,\u00C2\u00A088:\u00C2\u00A01341\u00E2\u0080\u00901358.\u00C2\u00A0\u00C2\u00A0 Barrie,\u00C2\u00A0C.T.,\u00C2\u00A0Cathles,\u00C2\u00A0L.M.,\u00C2\u00A0and\u00C2\u00A0Erendi,\u00C2\u00A0A.\u00C2\u00A01999.\u00C2\u00A0Finite\u00C2\u00A0element\u00C2\u00A0and\u00C2\u00A0fluid\u00E2\u0080\u0090flow\u00C2\u00A0computer\u00C2\u00A0simulations\u00C2\u00A0of\u00C2\u00A0 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flank\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Huancabamba\u00C2\u00A0deflection,\u00C2\u00A0Ecuador.\u00C2\u00A0U.S.\u00C2\u00A0Geological\u00C2\u00A0Survey\u00C2\u00A0Open\u00E2\u0080\u0090File\u00C2\u00A0Report\u00C2\u00A082\u00E2\u0080\u0090206,\u00C2\u00A0 21\u00C2\u00A0p.\u00C2\u00A0 \u00C2\u00A0 Franklin,\u00C2\u00A0J.M.\u00C2\u00A0\u00C2\u00A01995.\u00C2\u00A0Volcanic\u00E2\u0080\u0090associated\u00C2\u00A0massive\u00C2\u00A0sulfide\u00C2\u00A0base\u00C2\u00A0metal:\u00C2\u00A0Geological\u00C2\u00A0Survey\u00C2\u00A0of\u00C2\u00A0Canada,\u00C2\u00A0 Geology\u00C2\u00A0of\u00C2\u00A0Canada,\u00C2\u00A0no.8,\u00C2\u00A0pp.\u00C2\u00A0158\u00E2\u0080\u0093183.\u00C2\u00A0 \u00C2\u00A0 Franklin,\u00C2\u00A0J.M.,\u00C2\u00A0Gibson,\u00C2\u00A0H.L.,\u00C2\u00A0Jonasson,\u00C2\u00A0I.R.,\u00C2\u00A0and\u00C2\u00A0Galley,\u00C2\u00A0A.G.\u00C2\u00A0\u00C2\u00A02005.\u00C2\u00A0\u00C2\u00A0Volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulfide\u00C2\u00A0 deposits.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0Economic\u00C2\u00A0Geology;\u00C2\u00A0one\u00C2\u00A0hundredth\u00C2\u00A0anniversary\u00C2\u00A0volume,\u00C2\u00A01905\u00E2\u0080\u00902005.\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0J.W.\u00C2\u00A0 Hedenquist,\u00C2\u00A0J.F.H.\u00C2\u00A0Thompson,\u00C2\u00A0R.J.\u00C2\u00A0Goldfarb\u00C2\u00A0and\u00C2\u00A0J.P.\u00C2\u00A0Richards.\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0Economic\u00C2\u00A0Geologists,\u00C2\u00A0pp.\u00C2\u00A0 523\u00E2\u0080\u0090560.\u00C2\u00A0 \u00C2\u00A0 Galley,\u00C2\u00A0A.G.,\u00C2\u00A0Bailes,\u00C2\u00A0A.H.,\u00C2\u00A0and\u00C2\u00A0Kitzler,\u00C2\u00A0G.\u00C2\u00A0\u00C2\u00A01993.\u00C2\u00A0\u00C2\u00A0Geological\u00C2\u00A0setting\u00C2\u00A0and\u00C2\u00A0hydrothermal\u00C2\u00A0evolution\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 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Weis\u00C2\u00A0D.,\u00C2\u00A0Kieffer\u00C2\u00A0B.,\u00C2\u00A0Maerschalk\u00C2\u00A0C.,\u00C2\u00A0Pretorius\u00C2\u00A0W.\u00C2\u00A0and\u00C2\u00A0Barling\u00C2\u00A0J.\u00C2\u00A0\u00C2\u00A02005.\u00C2\u00A0\u00C2\u00A0High\u00E2\u0080\u0090precision\u00C2\u00A0Pb\u00E2\u0080\u0090Sr\u00E2\u0080\u0090Nd\u00E2\u0080\u0090Hf\u00C2\u00A0 isotopic\u00C2\u00A0characterization\u00C2\u00A0of\u00C2\u00A0USGS\u00C2\u00A0BHVO\u00E2\u0080\u00901\u00C2\u00A0and\u00C2\u00A0BHVO\u00E2\u0080\u00902\u00C2\u00A0reference\u00C2\u00A0materials.\u00C2\u00A0\u00C2\u00A0Geochemistry,\u00C2\u00A0 Geophysics,\u00C2\u00A0Geosystems,\u00C2\u00A0DOI\u00C2\u00A0number\u00C2\u00A010.1029/2004GC000852.\u00C2\u00A0 Winter,\u00C2\u00A0L.S.,\u00C2\u00A0Tosdal,\u00C2\u00A0R.,\u00C2\u00A0Franklin,\u00C2\u00A0J.M.,\u00C2\u00A0Tegart,\u00C2\u00A0P.\u00C2\u00A0\u00C2\u00A02004.\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0Reconstructed\u00C2\u00A0Cretaceous\u00C2\u00A0Depositional\u00C2\u00A0 Setting\u00C2\u00A0for\u00C2\u00A0Giant\u00C2\u00A0Volcanogenic\u00C2\u00A0Massive\u00C2\u00A0Sulfide\u00C2\u00A0Deposits\u00C2\u00A0at\u00C2\u00A0Tambogrande,\u00C2\u00A0Northwestern\u00C2\u00A0Per\u00C3\u00BA.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0 Special\u00C2\u00A0Publication\u00C2\u00A011\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0Andean\u00C2\u00A0Metallogeny:\u00C2\u00A0New\u00C2\u00A0Discoveries,\u00C2\u00A0Concepts,\u00C2\u00A0and\u00C2\u00A0Updates,\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0 R.H.\u00C2\u00A0Sillitoe,\u00C2\u00A0J.Perello,\u00C2\u00A0and\u00C2\u00A0C.Vidal.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0Economic\u00C2\u00A0Geologists,\u00C2\u00A0pp.\u00C2\u00A0319\u00E2\u0080\u0090340.\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Vergara,\u00C2\u00A0M.,\u00C2\u00A0Levi,\u00C2\u00A0B.,\u00C2\u00A0Nystr\u00C3\u00B6m,\u00C2\u00A0J.O.,\u00C2\u00A0Cancino,\u00C2\u00A0A.\u00C2\u00A0\u00C2\u00A01995.\u00C2\u00A0\u00C2\u00A0Jurassic\u00C2\u00A0and\u00C2\u00A0Early\u00C2\u00A0Cretaceous\u00C2\u00A0island\u00C2\u00A0arc\u00C2\u00A0 volcanism,\u00C2\u00A0extension,\u00C2\u00A0and\u00C2\u00A0subsidence\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Coast\u00C2\u00A0Range\u00C2\u00A0of\u00C2\u00A0central\u00C2\u00A0Chile.\u00C2\u00A0\u00C2\u00A0Geological\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0 America\u00C2\u00A0Bulletin,\u00C2\u00A0107:\u00C2\u00A01427\u00E2\u0080\u00901440.\u00C2\u00A0 Chapter\u00C2\u00A06.\u00C2\u00A0\u00C2\u00A0Summary,\u00C2\u00A0Discussion\u00C2\u00A0and\u00C2\u00A0Unresolved\u00C2\u00A0Questions\u00C2\u00A0 6.1\u00C2\u00A0 Summary\u00C2\u00A0and\u00C2\u00A0Main\u00C2\u00A0Conclusions\u00C2\u00A0 The\u00C2\u00A0Cu\u00E2\u0080\u0090Zn\u00E2\u0080\u0090Au\u00E2\u0080\u0090Ag\u00C2\u00A0volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0(VMS)\u00C2\u00A0deposits\u00C2\u00A0at\u00C2\u00A0Tambogrande,\u00C2\u00A0are\u00C2\u00A0one\u00C2\u00A0 of\u00C2\u00A0most\u00C2\u00A0significant\u00C2\u00A0metal\u00C2\u00A0accumulations\u00C2\u00A0of\u00C2\u00A0their\u00C2\u00A0type\u00C2\u00A0globally.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0deposits\u00C2\u00A0formed\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0 Cretaceous\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0of\u00C2\u00A0northwestern\u00C2\u00A0Per\u00C3\u00BA,\u00C2\u00A0the\u00C2\u00A0result\u00C2\u00A0of\u00C2\u00A0an\u00C2\u00A0early\u00C2\u00A0Andean\u00C2\u00A0continental\u00C2\u00A0 margin\u00C2\u00A0arc\u00E2\u0080\u0090rift\u00C2\u00A0system.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0elucidation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0timing\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0formation,\u00C2\u00A0as\u00C2\u00A0well\u00C2\u00A0as\u00C2\u00A0the\u00C2\u00A0tectonic,\u00C2\u00A0 regional\u00C2\u00A0geological,\u00C2\u00A0and\u00C2\u00A0paleo\u00E2\u0080\u0090deposition\u00C2\u00A0setting\u00C2\u00A0are\u00C2\u00A0the\u00C2\u00A0salient\u00C2\u00A0goals\u00C2\u00A0of\u00C2\u00A0this\u00C2\u00A0study.\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0 multidisciplinary\u00C2\u00A0approach\u00C2\u00A0was\u00C2\u00A0employed\u00C2\u00A0for\u00C2\u00A0this\u00C2\u00A0research\u00C2\u00A0project,\u00C2\u00A0which\u00C2\u00A0included\u00C2\u00A0mapping,\u00C2\u00A0 three\u00E2\u0080\u0090dimensional\u00C2\u00A0paleo\u00E2\u0080\u0090seafloor\u00C2\u00A0reconstructions,\u00C2\u00A0geochronology,\u00C2\u00A0lithogeochemistry\u00C2\u00A0and\u00C2\u00A0 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the\u00C2\u00A0development\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin,\u00C2\u00A0and\u00C2\u00A0ultimately\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0formation\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0at\u00C2\u00A0 Tambogrande.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Analogous\u00C2\u00A0modern\u00C2\u00A0ensialic\u00C2\u00A0arc\u00C2\u00A0rift\u00C2\u00A0settings\u00C2\u00A0include\u00C2\u00A0the\u00C2\u00A0Manus\u00C2\u00A0Basin\u00C2\u00A0(Taylor\u00C2\u00A0and\u00C2\u00A0 Martinez,\u00C2\u00A01996)\u00C2\u00A0and\u00C2\u00A0Bransfield\u00C2\u00A0Strait\u00C2\u00A0(Lawver\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01995;\u00C2\u00A0Gonz\u00C3\u00A1lez\u00E2\u0080\u0090Casado\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02000).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0 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sedimentary\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0Four\u00C2\u00A0formations\u00C2\u00A0are\u00C2\u00A0defined\u00C2\u00A0in\u00C2\u00A0this\u00C2\u00A0study,\u00C2\u00A0including\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 Formation\u00C2\u00A0(Phase\u00C2\u00A01),\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0El\u00C2\u00A0Ereo,\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0and\u00C2\u00A0Lancones\u00C2\u00A0formations\u00C2\u00A0(Phase\u00C2\u00A02).\u00C2\u00A0\u00C2\u00A0VMS\u00C2\u00A0 deposits\u00C2\u00A0are\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0rhyolite\u00C2\u00A0flow\u00C2\u00A0dome\u00C2\u00A0complexes\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0Formation\u00C2\u00A0 only\u00C2\u00A0and\u00C2\u00A0are\u00C2\u00A0confined\u00C2\u00A0to\u00C2\u00A0a\u00C2\u00A0narrow\u00C2\u00A0time\u00E2\u0080\u0090stratigraphic\u00C2\u00A0horizon\u00C2\u00A0(Chapter\u00C2\u00A03).\u00C2\u00A0 Chapter\u00C2\u00A06\u00C2\u00A0 Page\u00C2\u00A0193\u00C2\u00A0 \u00C2\u00A0 3) The\u00C2\u00A0paleo\u00E2\u0080\u0090depositional\u00C2\u00A0setting\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Tambogrande\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0(Chapter\u00C2\u00A03)\u00C2\u00A0is\u00C2\u00A0 characterized\u00C2\u00A0by\u00C2\u00A0the\u00C2\u00A0development\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0subaqueous,\u00C2\u00A0~250\u00C2\u00A0m\u00E2\u0080\u0090thick\u00C2\u00A0rhyolite\u00C2\u00A0lava\u00C2\u00A0flow\u00E2\u0080\u0090dome\u00C2\u00A0 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pre\u00E2\u0080\u0090existing\u00C2\u00A0volcanic\u00C2\u00A0or\u00C2\u00A0sedimentary\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0focusing\u00C2\u00A0of\u00C2\u00A0mineralizing\u00C2\u00A0hydrothermal\u00C2\u00A0fluid\u00C2\u00A0 through\u00C2\u00A0growing\u00C2\u00A0sulphide\u00C2\u00A0mounds\u00C2\u00A0within\u00C2\u00A0deep\u00C2\u00A0seafloor\u00C2\u00A0depressions\u00C2\u00A0resulted\u00C2\u00A0in\u00C2\u00A0efficient\u00C2\u00A0 deposition\u00C2\u00A0and\u00C2\u00A0is\u00C2\u00A0considered\u00C2\u00A0key\u00C2\u00A0to\u00C2\u00A0forming\u00C2\u00A0and\u00C2\u00A0preserving\u00C2\u00A0the\u00C2\u00A0large\u00C2\u00A0accumulations\u00C2\u00A0of\u00C2\u00A0sulphide\u00C2\u00A0 at\u00C2\u00A0Tambogrande.\u00C2\u00A0\u00C2\u00A0 4) A\u00C2\u00A0regional\u00C2\u00A0evaluation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0igneous\u00C2\u00A0petrogenesis\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0bimodal,\u00C2\u00A0mafic\u00E2\u0080\u0090dominated\u00C2\u00A0 volcanic\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0suggests\u00C2\u00A0magma\u00C2\u00A0genesis\u00C2\u00A0occurred\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0supra\u00E2\u0080\u0090subduction\u00C2\u00A0 zone\u00C2\u00A0setting\u00C2\u00A0and\u00C2\u00A0was\u00C2\u00A0dominated\u00C2\u00A0by\u00C2\u00A0mantle\u00C2\u00A0sources,\u00C2\u00A0though\u00C2\u00A0continental\u00C2\u00A0basement\u00C2\u00A0was\u00C2\u00A0variably\u00C2\u00A0 involved.\u00C2\u00A0\u00C2\u00A0All\u00C2\u00A0mafic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0display\u00C2\u00A0prominent\u00C2\u00A0negative\u00C2\u00A0Nb\u00C2\u00A0 Chapter\u00C2\u00A06\u00C2\u00A0 Page\u00C2\u00A0194\u00C2\u00A0 \u00C2\u00A0 anomalies\u00C2\u00A0on\u00C2\u00A0primitive\u00C2\u00A0mantle\u00E2\u0080\u0090normalized\u00C2\u00A0trace\u00C2\u00A0element\u00C2\u00A0plots,\u00C2\u00A0similar\u00C2\u00A0to\u00C2\u00A0arc\u00C2\u00A0magmatic\u00C2\u00A0rocks\u00C2\u00A0 (Chapter\u00C2\u00A04).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0island\u00C2\u00A0arc\u00C2\u00A0geochemical\u00C2\u00A0affinities\u00C2\u00A0are\u00C2\u00A0attributed\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0development\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 extensional\u00C2\u00A0volcanic\u00C2\u00A0arc\u00C2\u00A0within\u00C2\u00A0relatively\u00C2\u00A0thin\u00C2\u00A0continental\u00C2\u00A0crust,\u00C2\u00A0unlike\u00C2\u00A0the\u00C2\u00A0modern\u00C2\u00A0Andes.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0 interpretation\u00C2\u00A0is\u00C2\u00A0consistent\u00C2\u00A0with\u00C2\u00A0geophysical\u00C2\u00A0modeling\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0western\u00C2\u00A0Peruvian\u00C2\u00A0margin\u00C2\u00A0(Couch\u00C2\u00A0 et\u00C2\u00A0al.,\u00C2\u00A01981;\u00C2\u00A0Jones,\u00C2\u00A01981).\u00C2\u00A0\u00C2\u00A0No\u00C2\u00A0\u00E2\u0080\u0098non\u00E2\u0080\u0090arc\u00E2\u0080\u0099\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0(e.g.,\u00C2\u00A0MORBs)\u00C2\u00A0were\u00C2\u00A0identified,\u00C2\u00A0indicating\u00C2\u00A0 that\u00C2\u00A0back\u00E2\u0080\u0090arc\u00C2\u00A0spreading\u00C2\u00A0did\u00C2\u00A0not\u00C2\u00A0occur\u00C2\u00A0within\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin.\u00C2\u00A0\u00C2\u00A0Therefore,\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0 is\u00C2\u00A0interpreted\u00C2\u00A0to\u00C2\u00A0have\u00C2\u00A0formed\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0rifted\u00C2\u00A0arc.\u00C2\u00A0\u00C2\u00A0However,\u00C2\u00A0Cretaceous\u00C2\u00A0intra\u00E2\u0080\u0090continental\u00C2\u00A0alkaline\u00C2\u00A0 volcanic\u00C2\u00A0rocks\u00C2\u00A0are\u00C2\u00A0preserved\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Eastern\u00C2\u00A0Cordillera\u00C2\u00A0from\u00C2\u00A0Ecuador\u00C2\u00A0to\u00C2\u00A0Argentina\u00C2\u00A0and\u00C2\u00A0represent\u00C2\u00A0 the\u00C2\u00A0associated\u00C2\u00A0back\u00E2\u0080\u0090arc\u00C2\u00A0(Soler\u00C2\u00A0and\u00C2\u00A0Bonhomme,\u00C2\u00A01990;\u00C2\u00A0Viramonte\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01999;\u00C2\u00A0Barrag\u00C3\u00A1n\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A0 2005).\u00C2\u00A0\u00C2\u00A0Back\u00E2\u0080\u0090arc\u00C2\u00A0volcanism,\u00C2\u00A0however,\u00C2\u00A0did\u00C2\u00A0not\u00C2\u00A0evolve\u00C2\u00A0to\u00C2\u00A0sea\u00E2\u0080\u0090floor\u00C2\u00A0spreading.\u00C2\u00A0 Phase\u00C2\u00A01\u00C2\u00A0and\u00C2\u00A0phase\u00C2\u00A02\u00C2\u00A0volcanic\u00C2\u00A0events\u00C2\u00A0reflect\u00C2\u00A0different\u00C2\u00A0depositional\u00C2\u00A0environments\u00C2\u00A0 (Chapter\u00C2\u00A02)\u00C2\u00A0and\u00C2\u00A0also\u00C2\u00A0yield\u00C2\u00A0subtly\u00C2\u00A0different\u00C2\u00A0geochemical\u00C2\u00A0signatures\u00C2\u00A0(Chapter\u00C2\u00A04)\u00C2\u00A0which\u00C2\u00A0can\u00C2\u00A0be\u00C2\u00A0 used\u00C2\u00A0to\u00C2\u00A0interpret\u00C2\u00A0the\u00C2\u00A0tectonic\u00C2\u00A0evolution\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin.\u00C2\u00A0\u00C2\u00A0Phase\u00C2\u00A01\u00C2\u00A0Cerro\u00C2\u00A0San\u00C2\u00A0Lorenzo\u00C2\u00A0 Formation\u00C2\u00A0basalt\u00C2\u00A0displays\u00C2\u00A0relatively\u00C2\u00A0high\u00C2\u00A0LREE/HREE\u00C2\u00A0ratios\u00C2\u00A0(i.e.,\u00C2\u00A0La/Yb)\u00C2\u00A0and\u00C2\u00A0Zr/Y\u00C2\u00A0and\u00C2\u00A0have\u00C2\u00A0more\u00C2\u00A0 calc\u00E2\u0080\u0090alkaline\u00C2\u00A0affinities\u00C2\u00A0than\u00C2\u00A0the\u00C2\u00A0relatively\u00C2\u00A0tholeiitic\u00C2\u00A0Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0and\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0formations.\u00C2\u00A0\u00C2\u00A0 These\u00C2\u00A0subtle\u00C2\u00A0lithogeochemical\u00C2\u00A0variations\u00C2\u00A0suggest\u00C2\u00A0progressive\u00C2\u00A0partial\u00C2\u00A0melting\u00C2\u00A0and\u00C2\u00A0depletion\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0mantle\u00C2\u00A0wedge.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0addition,\u00C2\u00A0phase\u00C2\u00A01\u00C2\u00A0mafic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0are\u00C2\u00A0relatively\u00C2\u00A0primitive\u00C2\u00A0(i.e.,\u00C2\u00A0higher\u00C2\u00A0 Mg)\u00C2\u00A0compared\u00C2\u00A0with\u00C2\u00A0phase\u00C2\u00A02\u00C2\u00A0mafic\u00C2\u00A0rocks\u00C2\u00A0and\u00C2\u00A0were\u00C2\u00A0probably\u00C2\u00A0erupted\u00C2\u00A0through\u00C2\u00A0relatively\u00C2\u00A0thin\u00C2\u00A0 crust.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0more\u00C2\u00A0basaltic\u00E2\u0080\u0090andesite\u00C2\u00A0dominant\u00C2\u00A0compositions\u00C2\u00A0of\u00C2\u00A0phase\u00C2\u00A02\u00C2\u00A0formed\u00C2\u00A0in\u00C2\u00A0a\u00C2\u00A0maturing\u00C2\u00A0arc\u00C2\u00A0 with\u00C2\u00A0thickened\u00C2\u00A0crust\u00C2\u00A0(Green,\u00C2\u00A01980;\u00C2\u00A0Gill,\u00C2\u00A01981).\u00C2\u00A0\u00C2\u00A0Phase\u00C2\u00A01\u00C2\u00A0primitive\u00C2\u00A0lavas\u00C2\u00A0erupted\u00C2\u00A0during\u00C2\u00A0a\u00C2\u00A0period\u00C2\u00A0 of\u00C2\u00A0extension,\u00C2\u00A0attenuated\u00C2\u00A0crust,\u00C2\u00A0basin\u00C2\u00A0subsidence,\u00C2\u00A0and\u00C2\u00A0a\u00C2\u00A0high\u00C2\u00A0geothermal\u00C2\u00A0gradient.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Pb\u00E2\u0080\u0090Nd\u00E2\u0080\u0090Sr\u00C2\u00A0isotope\u00C2\u00A0systematics\u00C2\u00A0for\u00C2\u00A0mafic\u00C2\u00A0rocks\u00C2\u00A0indicate\u00C2\u00A0juvenile\u00C2\u00A0sources\u00C2\u00A0consistent\u00C2\u00A0with\u00C2\u00A0 suprasubduction\u00C2\u00A0zone\u00C2\u00A0(mantle\u00E2\u0080\u0093wedge)\u00C2\u00A0derivation\u00C2\u00A0(Chapter\u00C2\u00A05).\u00C2\u00A0\u00C2\u00A0All\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0analyzed\u00C2\u00A0 Chapter\u00C2\u00A06\u00C2\u00A0 Page\u00C2\u00A0195\u00C2\u00A0 \u00C2\u00A0 in\u00C2\u00A0the\u00C2\u00A0study\u00C2\u00A0are\u00C2\u00A0subalkaline,\u00C2\u00A0M\u00E2\u0080\u0090type,\u00C2\u00A0with\u00C2\u00A0negative\u00C2\u00A0Nb\u00C2\u00A0and\u00C2\u00A0Ti\u00C2\u00A0and\u00C2\u00A0positive\u00C2\u00A0Zr\u00C2\u00A0anomalies\u00C2\u00A0 (Chapter\u00C2\u00A04).\u00C2\u00A0\u00C2\u00A0These\u00C2\u00A0felsic\u00C2\u00A0rocks\u00C2\u00A0have\u00C2\u00A0a\u00C2\u00A0basaltic\u00C2\u00A0parentage\u00C2\u00A0that\u00C2\u00A0was\u00C2\u00A0obtained\u00C2\u00A0either\u00C2\u00A0directly\u00C2\u00A0or\u00C2\u00A0 indirectly,\u00C2\u00A0but\u00C2\u00A0exhibit\u00C2\u00A0variable\u00C2\u00A0radiogenic\u00C2\u00A0isotope\u00C2\u00A0signatures\u00C2\u00A0indicative\u00C2\u00A0of\u00C2\u00A0interaction\u00C2\u00A0 continental\u00C2\u00A0basement\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0suggests\u00C2\u00A0these\u00C2\u00A0felsic\u00C2\u00A0rocks\u00C2\u00A0were\u00C2\u00A0generated\u00C2\u00A0within,\u00C2\u00A0or\u00C2\u00A0at\u00C2\u00A0least\u00C2\u00A0 modified\u00C2\u00A0by,\u00C2\u00A0upper\u00C2\u00A0crustal\u00C2\u00A0material.\u00C2\u00A0\u00C2\u00A0Proterozoic\u00C2\u00A0zircon\u00C2\u00A0inheritance\u00C2\u00A0exhibited\u00C2\u00A0by\u00C2\u00A0some\u00C2\u00A0felsic\u00C2\u00A0 volcanic\u00C2\u00A0rocks\u00C2\u00A0(Chapter\u00C2\u00A02)\u00C2\u00A0also\u00C2\u00A0supports\u00C2\u00A0the\u00C2\u00A0conclusion\u00C2\u00A0that\u00C2\u00A0continental\u00C2\u00A0crust\u00C2\u00A0influenced\u00C2\u00A0felsic\u00C2\u00A0 magma\u00C2\u00A0genesis.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0phase\u00C2\u00A01,\u00C2\u00A0VMS\u00E2\u0080\u0090associated\u00C2\u00A0rhyolites\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0have\u00C2\u00A0low\u00C2\u00A0to\u00C2\u00A0moderate\u00C2\u00A0 HFSE\u00C2\u00A0contents,\u00C2\u00A0flat\u00C2\u00A0REE\u00C2\u00A0patterns\u00C2\u00A0and\u00C2\u00A0tholeiitic\u00E2\u0080\u0090transitional\u00C2\u00A0affinities\u00C2\u00A0characteristic\u00C2\u00A0of\u00C2\u00A0FII\u00E2\u0080\u0090type\u00C2\u00A0 rhyolites.\u00C2\u00A0\u00C2\u00A0Phase\u00C2\u00A02\u00C2\u00A0rhyolites\u00C2\u00A0are\u00C2\u00A0relatively\u00C2\u00A0more\u00C2\u00A0depleted\u00C2\u00A0and\u00C2\u00A0are\u00C2\u00A0akin\u00C2\u00A0to\u00C2\u00A0FIV\u00E2\u0080\u0090type\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0 rocks.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0phase\u00C2\u00A01\u00C2\u00A0rhyolites\u00C2\u00A0originated\u00C2\u00A0from\u00C2\u00A0high\u00E2\u0080\u0090temperature\u00C2\u00A0partial\u00C2\u00A0melts\u00C2\u00A0generated\u00C2\u00A0at\u00C2\u00A0 shallow\u00C2\u00A0crustal\u00C2\u00A0levels.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0petrogenetic\u00C2\u00A0assemblage\u00C2\u00A0of\u00C2\u00A0primitive\u00C2\u00A0mafic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0and\u00C2\u00A0FII\u00E2\u0080\u0090FIII\u00C2\u00A0 rhyolites\u00C2\u00A0is\u00C2\u00A0an\u00C2\u00A0important\u00C2\u00A0feature\u00C2\u00A0of\u00C2\u00A0phase\u00C2\u00A01\u00C2\u00A0and\u00C2\u00A0highlights\u00C2\u00A0the\u00C2\u00A0(i)\u00C2\u00A0high\u00E2\u0080\u0090temperature\u00C2\u00A0magmatism\u00C2\u00A0 and\u00C2\u00A0elevated\u00C2\u00A0geothermal\u00C2\u00A0gradient\u00C2\u00A0and\u00C2\u00A0(ii)\u00C2\u00A0extensional\u00C2\u00A0setting,\u00C2\u00A0both\u00C2\u00A0of\u00C2\u00A0which\u00C2\u00A0are\u00C2\u00A0critical\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0 initiation\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0robust\u00C2\u00A0hydrothermal\u00C2\u00A0circulation\u00C2\u00A0system\u00C2\u00A0and\u00C2\u00A0VMS\u00C2\u00A0formation.\u00C2\u00A0 5) Lead\u00C2\u00A0isotope\u00C2\u00A0systematics\u00C2\u00A0(Chapter\u00C2\u00A05)\u00C2\u00A0provide\u00C2\u00A0a\u00C2\u00A0constraint\u00C2\u00A0on\u00C2\u00A0metal\u00C2\u00A0sources\u00C2\u00A0and\u00C2\u00A0 therefore\u00C2\u00A0aid\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0understanding\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0hydrothermal\u00C2\u00A0system\u00C2\u00A0responsible\u00C2\u00A0for\u00C2\u00A0VMS\u00C2\u00A0formation\u00C2\u00A0 at\u00C2\u00A0Tambogrande.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0uniformity\u00C2\u00A0in\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0compositions\u00C2\u00A0of\u00C2\u00A0massive\u00C2\u00A0sulphides\u00C2\u00A0from\u00C2\u00A0 deposits\u00C2\u00A0TG1,\u00C2\u00A0TG3\u00C2\u00A0and\u00C2\u00A0B5\u00C2\u00A0suggests\u00C2\u00A0homogenization\u00C2\u00A0of\u00C2\u00A0Pb\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0hydrothermal\u00C2\u00A0system.\u00C2\u00A0\u00C2\u00A0Massive\u00C2\u00A0 sulphide\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0compositions\u00C2\u00A0define\u00C2\u00A0a\u00C2\u00A0steep\u00C2\u00A0array\u00C2\u00A0on\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0plots\u00C2\u00A0and\u00C2\u00A0are\u00C2\u00A0much\u00C2\u00A0less\u00C2\u00A0 radiogenic\u00C2\u00A0than\u00C2\u00A0continental\u00C2\u00A0crust\u00E2\u0080\u0090like\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks,\u00C2\u00A0but\u00C2\u00A0very\u00C2\u00A0similar\u00C2\u00A0to\u00C2\u00A0basalt\u00C2\u00A0Pb\u00C2\u00A0isotope\u00C2\u00A0 values.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0spatially\u00C2\u00A0and\u00C2\u00A0temporally\u00C2\u00A0associated\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0and\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0at\u00C2\u00A0 Tambogrande\u00C2\u00A0are\u00C2\u00A0genetically\u00C2\u00A0linked\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0anomalous\u00C2\u00A0heat\u00C2\u00A0input\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0upper\u00C2\u00A0crust,\u00C2\u00A0i.e.,\u00C2\u00A0 underplating\u00C2\u00A0of\u00C2\u00A0arc\u00C2\u00A0magmas.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0emplacement\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0mafic\u00C2\u00A0intrusion\u00C2\u00A0to\u00C2\u00A0sub\u00E2\u0080\u0090crustal\u00C2\u00A0levels\u00C2\u00A0acted\u00C2\u00A0 Chapter\u00C2\u00A06\u00C2\u00A0 Page\u00C2\u00A0196\u00C2\u00A0 \u00C2\u00A0 as\u00C2\u00A0a\u00C2\u00A0thermal\u00C2\u00A0driver\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0hydrothermal\u00C2\u00A0system.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0addition,\u00C2\u00A0this\u00C2\u00A0anomalous\u00C2\u00A0thermal\u00C2\u00A0input\u00C2\u00A0into\u00C2\u00A0 the\u00C2\u00A0upper\u00C2\u00A0crust\u00C2\u00A0also\u00C2\u00A0caused\u00C2\u00A0partial\u00C2\u00A0melting\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0juvenile\u00C2\u00A0mafic\u00C2\u00A0volcanic\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0resultant\u00C2\u00A0 felsic\u00C2\u00A0partial\u00C2\u00A0melts\u00C2\u00A0were\u00C2\u00A0contaminated\u00C2\u00A0by\u00C2\u00A0continental\u00C2\u00A0basement\u00C2\u00A0rocks\u00C2\u00A0and\u00C2\u00A0erupted\u00C2\u00A0as\u00C2\u00A0felsic\u00C2\u00A0 volcanic\u00C2\u00A0rocks.\u00C2\u00A0\u00C2\u00A0Although\u00C2\u00A0the\u00C2\u00A0felsic\u00C2\u00A0rocks\u00C2\u00A0may\u00C2\u00A0have\u00C2\u00A0played\u00C2\u00A0a\u00C2\u00A0role\u00C2\u00A0in\u00C2\u00A0heat\u00C2\u00A0transfer\u00C2\u00A0and\u00C2\u00A0enhanced\u00C2\u00A0 the\u00C2\u00A0robustness\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0hydrothermal\u00C2\u00A0system,\u00C2\u00A0the\u00C2\u00A0role\u00C2\u00A0of\u00C2\u00A0these\u00C2\u00A0rocks\u00C2\u00A0is\u00C2\u00A0considered\u00C2\u00A0largely\u00C2\u00A0passive\u00C2\u00A0 in\u00C2\u00A0the\u00C2\u00A0formation\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Tambogrande\u00C2\u00A0VMS\u00C2\u00A0deposits.\u00C2\u00A0\u00C2\u00A0Metals\u00C2\u00A0were\u00C2\u00A0leached\u00C2\u00A0almost\u00C2\u00A0exclusively\u00C2\u00A0 from\u00C2\u00A0mafic\u00C2\u00A0footwall\u00C2\u00A0strata.\u00C2\u00A0 In\u00C2\u00A0summary,\u00C2\u00A0the\u00C2\u00A0key\u00C2\u00A0contributions\u00C2\u00A0of\u00C2\u00A0this\u00C2\u00A0research\u00C2\u00A0project\u00C2\u00A0are\u00C2\u00A0summarized\u00C2\u00A0as\u00C2\u00A0follows:\u00C2\u00A0 (1)\u00C2\u00A0the\u00C2\u00A0thesis\u00C2\u00A0provides\u00C2\u00A0comprehensive\u00C2\u00A0baseline\u00C2\u00A0documentation\u00C2\u00A0of\u00C2\u00A0an\u00C2\u00A0economically\u00C2\u00A0significant\u00C2\u00A0 VMS\u00C2\u00A0district\u00C2\u00A0that\u00C2\u00A0has\u00C2\u00A0not\u00C2\u00A0hitherto\u00C2\u00A0been\u00C2\u00A0studied\u00C2\u00A0in\u00C2\u00A0any\u00C2\u00A0significant\u00C2\u00A0detail.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0work\u00C2\u00A0here\u00C2\u00A0is\u00C2\u00A0built\u00C2\u00A0 on\u00C2\u00A0a\u00C2\u00A0foundation\u00C2\u00A0of\u00C2\u00A0first\u00C2\u00A0understanding\u00C2\u00A0the\u00C2\u00A0regional\u00C2\u00A0geology,\u00C2\u00A0deposit\u00E2\u0080\u0090scale\u00C2\u00A0volcanic\u00C2\u00A0setting,\u00C2\u00A0and\u00C2\u00A0 deposit\u00C2\u00A0architecture;\u00C2\u00A0(2)\u00C2\u00A0research\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0basin\u00C2\u00A0has\u00C2\u00A0helped\u00C2\u00A0fill\u00C2\u00A0a\u00C2\u00A0regional\u00C2\u00A0void\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0 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the\u00C2\u00A0relationship\u00C2\u00A0to\u00C2\u00A0global\u00C2\u00A0plate\u00C2\u00A0tectonics;\u00C2\u00A0and\u00C2\u00A0(5)\u00C2\u00A0the\u00C2\u00A0research\u00C2\u00A0helps\u00C2\u00A0constrain\u00C2\u00A0models\u00C2\u00A0for\u00C2\u00A0VMS\u00C2\u00A0 genesis\u00C2\u00A0in\u00C2\u00A0terms\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0relationship\u00C2\u00A0to\u00C2\u00A0associated\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks,\u00C2\u00A0metal\u00C2\u00A0sources\u00C2\u00A0and\u00C2\u00A0 hydrothermal\u00C2\u00A0system\u00C2\u00A0generation.\u00C2\u00A0 Chapter\u00C2\u00A06\u00C2\u00A0 Page\u00C2\u00A0197\u00C2\u00A0 \u00C2\u00A0 6.2\u00C2\u00A0 Discussion\u00C2\u00A0and\u00C2\u00A0Ideas\u00C2\u00A0 6.2.1\u00C2\u00A0 Timing\u00C2\u00A0and\u00C2\u00A0Tectonic\u00C2\u00A0Setting\u00C2\u00A0 A\u00C2\u00A0peri\u00E2\u0080\u0090cratonic\u00C2\u00A0extensional\u00C2\u00A0setting\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0is\u00C2\u00A0implicit\u00C2\u00A0because\u00C2\u00A0the\u00C2\u00A0present\u00C2\u00A0 day\u00C2\u00A0volcanic\u00C2\u00A0sequence\u00C2\u00A0is\u00C2\u00A0~150\u00C2\u00A0km\u00C2\u00A0wide,\u00C2\u00A0with\u00C2\u00A0continental\u00C2\u00A0crust\u00C2\u00A0preserved\u00C2\u00A0adjacent\u00C2\u00A0to\u00C2\u00A0both\u00C2\u00A0 margins.\u00C2\u00A0\u00C2\u00A0Further,\u00C2\u00A0it\u00C2\u00A0is\u00C2\u00A0also\u00C2\u00A0underlain\u00C2\u00A0in\u00C2\u00A0part\u00C2\u00A0by\u00C2\u00A0continental\u00C2\u00A0basement\u00C2\u00A0as\u00C2\u00A0evidenced\u00C2\u00A0by\u00C2\u00A0 radiogenic\u00C2\u00A0isotopes\u00C2\u00A0and\u00C2\u00A0zircon\u00C2\u00A0inheritance.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0role\u00C2\u00A0of\u00C2\u00A0extensional\u00C2\u00A0geodynamics\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0 formation\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0has\u00C2\u00A0been\u00C2\u00A0frequently\u00C2\u00A0emphasized\u00C2\u00A0in\u00C2\u00A0ancient\u00C2\u00A0VMS\u00C2\u00A0settings\u00C2\u00A0(e.g.,\u00C2\u00A0 Sillitoe,\u00C2\u00A01982;\u00C2\u00A0Cathles,\u00C2\u00A01983;\u00C2\u00A0Swinden,\u00C2\u00A01991;\u00C2\u00A0Lentz,\u00C2\u00A01998;\u00C2\u00A0Hart\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02004)\u00C2\u00A0and\u00C2\u00A0observed\u00C2\u00A0in\u00C2\u00A0 modern\u00C2\u00A0VMS\u00C2\u00A0environments\u00C2\u00A0(Hannington\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02005).\u00C2\u00A0\u00C2\u00A0Although\u00C2\u00A0the\u00C2\u00A0kinematics\u00C2\u00A0of\u00C2\u00A0such\u00C2\u00A0modern\u00C2\u00A0 environments\u00C2\u00A0are\u00C2\u00A0relatively\u00C2\u00A0well\u00C2\u00A0understood,\u00C2\u00A0though\u00C2\u00A0often\u00C2\u00A0debated\u00C2\u00A0(e.g.,\u00C2\u00A0Bransfield\u00C2\u00A0Strait;\u00C2\u00A0 Lawver\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01995;\u00C2\u00A0Barker\u00C2\u00A0and\u00C2\u00A0Austin,\u00C2\u00A01998;\u00C2\u00A0Gonz\u00C3\u00A1lez\u00E2\u0080\u0090Casado\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02000;\u00C2\u00A0Fretzdorff\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A0 2004),\u00C2\u00A0the\u00C2\u00A0forces\u00C2\u00A0that\u00C2\u00A0controlled\u00C2\u00A0extension\u00C2\u00A0in\u00C2\u00A0ancient\u00C2\u00A0marginal\u00C2\u00A0arcs\u00C2\u00A0\u00C2\u00A0remain\u00C2\u00A0less\u00C2\u00A0well\u00C2\u00A0 understood.\u00C2\u00A0\u00C2\u00A0Extension\u00C2\u00A0can\u00C2\u00A0be\u00C2\u00A0accommodated\u00C2\u00A0in\u00C2\u00A0various\u00C2\u00A0ways.\u00C2\u00A0\u00C2\u00A0Extension\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0was\u00C2\u00A0 probably\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0slab\u00C2\u00A0rollback\u00C2\u00A0and\u00C2\u00A0oceanwards\u00C2\u00A0retreat\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0overlying\u00C2\u00A0arc\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0 subduction\u00C2\u00A0of\u00C2\u00A0relatively\u00C2\u00A0old\u00C2\u00A0and\u00C2\u00A0dense\u00C2\u00A0oceanic\u00C2\u00A0material\u00C2\u00A0during\u00C2\u00A0Albian\u00C2\u00A0times\u00C2\u00A0(Soler\u00C2\u00A0and\u00C2\u00A0 Bonhomme,\u00C2\u00A01990).\u00C2\u00A0\u00C2\u00A0Alternatively,\u00C2\u00A0and\u00C2\u00A0considered\u00C2\u00A0less\u00C2\u00A0likely\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0volume\u00C2\u00A0of\u00C2\u00A0volcanic\u00C2\u00A0 material\u00C2\u00A0erupted,\u00C2\u00A0transpressional\u00C2\u00A0or\u00C2\u00A0transtensional\u00C2\u00A0tectonics\u00C2\u00A0may\u00C2\u00A0also\u00C2\u00A0have\u00C2\u00A0controlled\u00C2\u00A0the\u00C2\u00A0 development\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0as\u00C2\u00A0a\u00C2\u00A0pull\u00E2\u0080\u0090apart\u00C2\u00A0basin.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 The\u00C2\u00A0timing\u00C2\u00A0of\u00C2\u00A0VMS\u00C2\u00A0formation\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0is\u00C2\u00A0temporally\u00C2\u00A0linked\u00C2\u00A0with\u00C2\u00A0major\u00C2\u00A0plate\u00C2\u00A0tectonic\u00C2\u00A0 reorganizations,\u00C2\u00A0specifically,\u00C2\u00A0the\u00C2\u00A0final\u00C2\u00A0breakup\u00C2\u00A0of\u00C2\u00A0Gondwana\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0Albian\u00C2\u00A0rifting\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 equatorial\u00C2\u00A0South\u00C2\u00A0Atlantic\u00C2\u00A0(Scotese,\u00C2\u00A01991).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0extensional\u00C2\u00A0basin\u00C2\u00A0tectonics\u00C2\u00A0and\u00C2\u00A0VMS\u00E2\u0080\u0090setting\u00C2\u00A0was\u00C2\u00A0 terminated\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0ultimate\u00C2\u00A0separation\u00C2\u00A0of\u00C2\u00A0South\u00C2\u00A0America\u00C2\u00A0from\u00C2\u00A0Africa\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0onset\u00C2\u00A0of\u00C2\u00A0 spreading\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0South\u00C2\u00A0Atlantic,\u00C2\u00A0causing\u00C2\u00A0the\u00C2\u00A0rotation\u00C2\u00A0and\u00C2\u00A0westward\u00C2\u00A0drift\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0South\u00C2\u00A0American\u00C2\u00A0 continent\u00C2\u00A0and\u00C2\u00A0contractional\u00C2\u00A0tectonics\u00C2\u00A0along\u00C2\u00A0the\u00C2\u00A0western\u00C2\u00A0margin,\u00C2\u00A0although\u00C2\u00A0the\u00C2\u00A0exact\u00C2\u00A0kinematics\u00C2\u00A0 Chapter\u00C2\u00A06\u00C2\u00A0 Page\u00C2\u00A0198\u00C2\u00A0 \u00C2\u00A0 are\u00C2\u00A0uncertain\u00C2\u00A0(Soler\u00C2\u00A0and\u00C2\u00A0Bonhomme,\u00C2\u00A01990).\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0general,\u00C2\u00A0there\u00C2\u00A0appears\u00C2\u00A0to\u00C2\u00A0be\u00C2\u00A0an\u00C2\u00A0association\u00C2\u00A0of\u00C2\u00A0 VMS\u00C2\u00A0deposits\u00C2\u00A0with\u00C2\u00A0major\u00C2\u00A0plate\u00C2\u00A0re\u00E2\u0080\u0090organizations\u00C2\u00A0elsewhere\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0rock\u00C2\u00A0record\u00C2\u00A0(Barley\u00C2\u00A0and\u00C2\u00A0 Groves,\u00C2\u00A01992;\u00C2\u00A0Groves\u00C2\u00A0and\u00C2\u00A0Bierlein,\u00C2\u00A02007).\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0conclusion\u00C2\u00A0is\u00C2\u00A0often\u00C2\u00A0made\u00C2\u00A0based\u00C2\u00A0on\u00C2\u00A0the\u00C2\u00A0shift\u00C2\u00A0from\u00C2\u00A0 arc\u00C2\u00A0to\u00C2\u00A0non\u00E2\u0080\u0090arc\u00C2\u00A0(i.e.,\u00C2\u00A0MORB)\u00C2\u00A0volcanism,\u00C2\u00A0indicating\u00C2\u00A0the\u00C2\u00A0transition\u00C2\u00A0from\u00C2\u00A0arc\u00C2\u00A0rifting\u00C2\u00A0to\u00C2\u00A0active\u00C2\u00A0 spreading\u00C2\u00A0(e.g.,\u00C2\u00A0Swinden,\u00C2\u00A01991;\u00C2\u00A0Swinden\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01997;\u00C2\u00A0Wyman\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01999;\u00C2\u00A0Piercey,\u00C2\u00A02007).\u00C2\u00A0\u00C2\u00A0At\u00C2\u00A0 Tambogrande,\u00C2\u00A0the\u00C2\u00A0transition\u00C2\u00A0was\u00C2\u00A0not\u00C2\u00A0from\u00C2\u00A0arc\u00C2\u00A0to\u00C2\u00A0non\u00E2\u0080\u0090arc\u00C2\u00A0volcanism,\u00C2\u00A0rather\u00C2\u00A0a\u00C2\u00A0continuous\u00C2\u00A0arc\u00C2\u00A0 volcanic\u00C2\u00A0sequence\u00C2\u00A0evolved\u00C2\u00A0from\u00C2\u00A0extensional\u00C2\u00A0to\u00C2\u00A0a\u00C2\u00A0more\u00C2\u00A0neutral\u00C2\u00A0and\u00C2\u00A0eventually\u00C2\u00A0contractional\u00C2\u00A0 tectonic\u00C2\u00A0regime.\u00C2\u00A0\u00C2\u00A0VMS\u00C2\u00A0deposits\u00C2\u00A0are\u00C2\u00A0commonly\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0\u00E2\u0080\u0098aborted\u00C2\u00A0arc\u00C2\u00A0rifts\u00E2\u0080\u0099\u00C2\u00A0(e.g.,\u00C2\u00A0Kuroko;\u00C2\u00A0 Cathles\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01983)\u00C2\u00A0which\u00C2\u00A0typify\u00C2\u00A0microplate\u00C2\u00A0tectonic\u00C2\u00A0regimes\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0SW\u00C2\u00A0Pacific\u00C2\u00A0Manus\u00C2\u00A0Basin\u00C2\u00A0 (Martinez\u00C2\u00A0and\u00C2\u00A0Taylor,\u00C2\u00A01996).\u00C2\u00A0 6.2.2\u00C2\u00A0 Where\u00E2\u0080\u0099s\u00C2\u00A0the\u00C2\u00A0Intrusion?\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 VMS\u00C2\u00A0genetic\u00C2\u00A0models\u00C2\u00A0advocate\u00C2\u00A0an\u00C2\u00A0igneous\u00C2\u00A0heat\u00C2\u00A0source\u00C2\u00A0to\u00C2\u00A0drive\u00C2\u00A0a\u00C2\u00A0hydrothermal\u00C2\u00A0circulation\u00C2\u00A0 system\u00C2\u00A0and\u00C2\u00A0possibly\u00C2\u00A0to\u00C2\u00A0contribute\u00C2\u00A0metals\u00C2\u00A0(Lydon,\u00C2\u00A01988;\u00C2\u00A0Large,\u00C2\u00A01992;\u00C2\u00A0Galley,\u00C2\u00A01993;\u00C2\u00A0Franklin,\u00C2\u00A0 1995;\u00C2\u00A0Ohmoto,\u00C2\u00A01996;\u00C2\u00A0\u00C2\u00A0Hart\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02004;\u00C2\u00A0Franklin\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A02005)\u00C2\u00A0.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0source\u00C2\u00A0of\u00C2\u00A0heat\u00C2\u00A0is\u00C2\u00A0generally\u00C2\u00A0 considered\u00C2\u00A0to\u00C2\u00A0be\u00C2\u00A0new\u00C2\u00A0magma\u00C2\u00A0input\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0upper\u00C2\u00A0crust.\u00C2\u00A0\u00C2\u00A0Heat\u00E2\u0080\u0090\u00C2\u00A0and\u00C2\u00A0fluid\u00E2\u0080\u0090flow\u00C2\u00A0modeling\u00C2\u00A0indicate\u00C2\u00A0 that\u00C2\u00A0substantial\u00C2\u00A0thermal\u00C2\u00A0input\u00C2\u00A0into\u00C2\u00A0the\u00C2\u00A0upper\u00C2\u00A0crust\u00C2\u00A0is\u00C2\u00A0required\u00C2\u00A0in\u00C2\u00A0order\u00C2\u00A0to\u00C2\u00A0sustain\u00C2\u00A0a\u00C2\u00A0 hydrothermal\u00C2\u00A0convection\u00C2\u00A0system\u00C2\u00A0capable\u00C2\u00A0of\u00C2\u00A0producing\u00C2\u00A0giant\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0(Cathles\u00C2\u00A0 et\u00C2\u00A0al.,\u00C2\u00A01981;\u00C2\u00A0Cathles\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01999;\u00C2\u00A0Barrie\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01999).\u00C2\u00A0\u00C2\u00A0Furthermore,\u00C2\u00A0the\u00C2\u00A0thermal\u00C2\u00A0input\u00C2\u00A0required\u00C2\u00A0is\u00C2\u00A0 most\u00C2\u00A0likely\u00C2\u00A0accommodated\u00C2\u00A0by\u00C2\u00A0mantle\u00E2\u0080\u0090derived\u00C2\u00A0intrusions\u00C2\u00A0(mafic,\u00C2\u00A0or\u00C2\u00A0ultramafic)\u00C2\u00A0emplaced\u00C2\u00A0within\u00C2\u00A0 the\u00C2\u00A0upper\u00C2\u00A0crust\u00C2\u00A0(Barrie\u00C2\u00A0et\u00C2\u00A0al.,\u00C2\u00A01999).\u00C2\u00A0\u00C2\u00A0That\u00C2\u00A0bimodal\u00E2\u0080\u0090volcanism\u00C2\u00A0did\u00C2\u00A0not\u00C2\u00A0bury\u00C2\u00A0the\u00C2\u00A0deposits\u00C2\u00A0at\u00C2\u00A0 Tambogrande\u00C2\u00A0but\u00C2\u00A0was\u00C2\u00A0episodic\u00C2\u00A0during\u00C2\u00A0deposition\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0massive\u00C2\u00A0sulphides\u00C2\u00A0suggests\u00C2\u00A0stable\u00C2\u00A0and\u00C2\u00A0 likely\u00C2\u00A0periodic\u00C2\u00A0replenishment\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0magma\u00C2\u00A0chamber(s).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0presence\u00C2\u00A0of\u00C2\u00A0petrochemically\u00C2\u00A0 variable,\u00C2\u00A0volumetrically\u00C2\u00A0minor\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0intercalated\u00C2\u00A0with\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0suggests\u00C2\u00A0 a\u00C2\u00A0complex\u00C2\u00A0magmatic\u00C2\u00A0system\u00C2\u00A0erupted\u00C2\u00A0small\u00C2\u00A0batches\u00C2\u00A0of\u00C2\u00A0magma\u00C2\u00A0during\u00C2\u00A0and\u00C2\u00A0after\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0 Chapter\u00C2\u00A06\u00C2\u00A0 Page\u00C2\u00A0199\u00C2\u00A0 \u00C2\u00A0 deposit\u00C2\u00A0formation,\u00C2\u00A0likely\u00C2\u00A0the\u00C2\u00A0result\u00C2\u00A0of\u00C2\u00A0a\u00C2\u00A0long\u00E2\u0080\u0090lived\u00C2\u00A0magma\u00C2\u00A0chamber\u00C2\u00A0and\u00C2\u00A0area\u00C2\u00A0of\u00C2\u00A0elevated\u00C2\u00A0 geothermal\u00C2\u00A0gradient.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0volcanic\u00C2\u00A0stratigraphy\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0is\u00C2\u00A0near\u00C2\u00A0flat\u00C2\u00A0lying\u00C2\u00A0and\u00C2\u00A0not\u00C2\u00A0 deeply\u00C2\u00A0eroded,\u00C2\u00A0therefore,\u00C2\u00A0such\u00C2\u00A0intrusions\u00C2\u00A0are\u00C2\u00A0not\u00C2\u00A0likely\u00C2\u00A0exposed\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0region.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 6.3\u00C2\u00A0 Outstanding\u00C2\u00A0Issues\u00C2\u00A0and\u00C2\u00A0Directions\u00C2\u00A0for\u00C2\u00A0Future\u00C2\u00A0Research\u00C2\u00A0 6.3.1\u00C2\u00A0 At\u00C2\u00A0Tambogrande\u00C2\u00A0and\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Lancones\u00C2\u00A0Basin\u00C2\u00A0 \u00E2\u0080\u00A2 Was\u00C2\u00A0Tambogrande\u00C2\u00A0related\u00C2\u00A0to\u00C2\u00A0a\u00C2\u00A0long\u00E2\u0080\u0090lived\u00C2\u00A0hydrothemal\u00C2\u00A0system?\u00C2\u00A0\u00C2\u00A0An\u00C2\u00A0attempt\u00C2\u00A0to\u00C2\u00A0date\u00C2\u00A0the\u00C2\u00A0 immediate\u00C2\u00A0footwall\u00C2\u00A0and\u00C2\u00A0hanging\u00C2\u00A0wall\u00C2\u00A0rocks\u00C2\u00A0at\u00C2\u00A0Tambogrande\u00C2\u00A0was\u00C2\u00A0not\u00C2\u00A0successful\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0 the\u00C2\u00A0lack\u00C2\u00A0of\u00C2\u00A0zircons\u00C2\u00A0in\u00C2\u00A0most\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks,\u00C2\u00A0likely\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0inferred\u00C2\u00A0high\u00C2\u00A0 temperatures\u00C2\u00A0at\u00C2\u00A0eruption\u00C2\u00A0(Chapter\u00C2\u00A02).\u00C2\u00A0\u00C2\u00A0For\u00C2\u00A0comparison,\u00C2\u00A0Bleeker\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1999)\u00C2\u00A0suggest\u00C2\u00A0the\u00C2\u00A0 Kidd\u00C2\u00A0Creek\u00C2\u00A0ore\u00C2\u00A0body\u00C2\u00A0formed\u00C2\u00A0during\u00C2\u00A0a\u00C2\u00A0prolonged,\u00C2\u00A0but\u00C2\u00A0episodic,\u00C2\u00A0period\u00C2\u00A0of\u00C2\u00A0hydrothermal\u00C2\u00A0 activity\u00C2\u00A0spanning\u00C2\u00A0~\u00C2\u00A05\u00C2\u00A0Ma.\u00C2\u00A0\u00C2\u00A0How\u00C2\u00A0else\u00C2\u00A0can\u00C2\u00A0these\u00C2\u00A0(and\u00C2\u00A0other)\u00C2\u00A0stratiform\u00C2\u00A0volcanic\u00E2\u0080\u0090hosted\u00C2\u00A0 deposits\u00C2\u00A0be\u00C2\u00A0dated?\u00C2\u00A0 \u00E2\u0080\u00A2 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of\u00C2\u00A0the\u00C2\u00A0Raspas\u00C2\u00A0metamorphic\u00C2\u00A0complex\u00C2\u00A0(SW\u00C2\u00A0Ecuador);\u00C2\u00A0geochemical\u00C2\u00A0and\u00C2\u00A0isotopic\u00C2\u00A0constraints;\u00C2\u00A0 Tectonophysics,\u00C2\u00A0345:\u00C2\u00A083\u00E2\u0080\u0090102.\u00C2\u00A0 \u00C2\u00A0 Cathles,\u00C2\u00A0L.\u00C2\u00A0M.\u00C2\u00A0\u00C2\u00A01981.\u00C2\u00A0\u00C2\u00A0Fluid\u00C2\u00A0flow\u00C2\u00A0and\u00C2\u00A0genesis\u00C2\u00A0of\u00C2\u00A0hydrothermal\u00C2\u00A0ore\u00C2\u00A0deposits.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0Economic\u00C2\u00A0 geology;\u00C2\u00A0Seventy\u00E2\u0080\u0090fifth\u00C2\u00A0Anniversary\u00C2\u00A0Volume;\u00C2\u00A01905\u00E2\u0080\u00901980.\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0B.J.\u00C2\u00A0Skinner.\u00C2\u00A0Economic\u00C2\u00A0 Geology\u00C2\u00A0Publishing\u00C2\u00A0Co.,\u00C2\u00A0pp.\u00C2\u00A0424\u00E2\u0080\u0090457.\u00C2\u00A0 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Fretzdorff,\u00C2\u00A0S.,\u00C2\u00A0Worthington,\u00C2\u00A0T.\u00C2\u00A0J.,\u00C2\u00A0Haase,\u00C2\u00A0K.M.,\u00C2\u00A0H\u00C3\u00A9kinian,\u00C2\u00A0R.,\u00C2\u00A0Franz,\u00C2\u00A0L.,\u00C2\u00A0R.\u00C2\u00A0Keller,\u00C2\u00A0A.,\u00C2\u00A0and\u00C2\u00A0Stoffers,\u00C2\u00A0 P.\u00C2\u00A0\u00C2\u00A02004.\u00C2\u00A0\u00C2\u00A0Magmatism\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Bransfield\u00C2\u00A0Basin:\u00C2\u00A0Rifting\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0South\u00C2\u00A0Shetland\u00C2\u00A0Arc?\u00C2\u00A0\u00C2\u00A0Journal\u00C2\u00A0of\u00C2\u00A0 Geophysical\u00C2\u00A0Research,\u00C2\u00A0109,\u00C2\u00A0B12208,\u00C2\u00A019p.\u00C2\u00A0 \u00C2\u00A0 Galley,\u00C2\u00A0A.G.\u00C2\u00A0\u00C2\u00A01993.\u00C2\u00A0\u00C2\u00A0Semi\u00E2\u0080\u0090conformable\u00C2\u00A0alteration\u00C2\u00A0zones\u00C2\u00A0in\u00C2\u00A0volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0 districts.\u00C2\u00A0\u00C2\u00A0Journal\u00C2\u00A0of\u00C2\u00A0Geochemical\u00C2\u00A0Exploration,\u00C2\u00A048:\u00C2\u00A0175\u00E2\u0080\u0090200.\u00C2\u00A0 \u00C2\u00A0 Gill,\u00C2\u00A0J.E.\u00C2\u00A0\u00C2\u00A01981.\u00C2\u00A0\u00C2\u00A0Orogenic\u00C2\u00A0Andesites\u00C2\u00A0and\u00C2\u00A0Plate\u00C2\u00A0Tectonics.\u00C2\u00A0\u00C2\u00A0Springer\u00C2\u00A0Verlag,\u00C2\u00A0390\u00C2\u00A0p.\u00C2\u00A0 \u00C2\u00A0 Gonz\u00C3\u00A1lez\u00E2\u0080\u0090Casado,\u00C2\u00A0J.M.,\u00C2\u00A0Giner\u00C2\u00A0Robles,\u00C2\u00A0J.L.,\u00C2\u00A0L\u00C3\u00B3pez\u00E2\u0080\u0090Mart\u00C3\u00ADnez,\u00C2\u00A0.J\u00C2\u00A0\u00C2\u00A02000.\u00C2\u00A0\u00C2\u00A0Bransfield\u00C2\u00A0Basin,\u00C2\u00A0Antarctic\u00C2\u00A0 Peninsula:\u00C2\u00A0Not\u00C2\u00A0a\u00C2\u00A0normal\u00C2\u00A0backarc\u00C2\u00A0basin.\u00C2\u00A0\u00C2\u00A0Geology:\u00C2\u00A028,\u00C2\u00A01043\u00E2\u0080\u00931046.\u00C2\u00A0 \u00C2\u00A0 Goodfellow,\u00C2\u00A0W.D.\u00C2\u00A0and\u00C2\u00A0Zierenberg,\u00C2\u00A0R.A.\u00C2\u00A0\u00C2\u00A01999.\u00C2\u00A0\u00C2\u00A0Genesis\u00C2\u00A0of\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0at\u00C2\u00A0 sediment\u00E2\u0080\u0090covered\u00C2\u00A0spreading\u00C2\u00A0centers.\u00C2\u00A0\u00C2\u00A0Reviews\u00C2\u00A0in\u00C2\u00A0Economic\u00C2\u00A0Geology,\u00C2\u00A0Volume\u00C2\u00A08,\u00C2\u00A0pp.\u00C2\u00A0297\u00E2\u0080\u0090 324.\u00C2\u00A0 \u00C2\u00A0 Green,\u00C2\u00A0T.H.\u00C2\u00A0\u00C2\u00A01980.\u00C2\u00A0\u00C2\u00A0Island\u00C2\u00A0arc\u00C2\u00A0and\u00C2\u00A0continent\u00E2\u0080\u0090building\u00C2\u00A0magmatism;\u00C2\u00A0a\u00C2\u00A0review\u00C2\u00A0of\u00C2\u00A0petrogenic\u00C2\u00A0models\u00C2\u00A0 based\u00C2\u00A0on\u00C2\u00A0experimental\u00C2\u00A0petrology\u00C2\u00A0and\u00C2\u00A0geochemistry.\u00C2\u00A0\u00C2\u00A0Tectonophysics,\u00C2\u00A063:\u00C2\u00A0367\u00E2\u0080\u0090385.\u00C2\u00A0 \u00C2\u00A0 Groves,\u00C2\u00A0D.\u00C2\u00A0I.\u00C2\u00A0and\u00C2\u00A0Bierlein,\u00C2\u00A0F.\u00C2\u00A0P.\u00C2\u00A0\u00C2\u00A02007.\u00C2\u00A0\u00C2\u00A0Geodynamic\u00C2\u00A0settings\u00C2\u00A0of\u00C2\u00A0mineral\u00C2\u00A0deposit\u00C2\u00A0systems.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0Journal\u00C2\u00A0 of\u00C2\u00A0the\u00C2\u00A0Geological\u00C2\u00A0Society,\u00C2\u00A0164:\u00C2\u00A019\u00E2\u0080\u009030.\u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0 Chapter\u00C2\u00A06\u00C2\u00A0 Page\u00C2\u00A0206\u00C2\u00A0 \u00C2\u00A0 Hannington,\u00C2\u00A0M.D.,\u00C2\u00A0de\u00C2\u00A0Ronde,\u00C2\u00A0C.E.J.,\u00C2\u00A0and\u00C2\u00A0Petersen,\u00C2\u00A0S.\u00C2\u00A0\u00C2\u00A02005.\u00C2\u00A0\u00C2\u00A0Sea\u00E2\u0080\u0090floor\u00C2\u00A0tectonics\u00C2\u00A0and\u00C2\u00A0submarine\u00C2\u00A0 hydrothermal\u00C2\u00A0systems.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0100th\u00C2\u00A0Anniversary\u00C2\u00A0Volume,\u00C2\u00A01905\u00E2\u0080\u00902005.\u00C2\u00A0\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0Jeffrey\u00C2\u00A0W.\u00C2\u00A0 Hedenquist,\u00C2\u00A0J.F.H.\u00C2\u00A0Thompson,\u00C2\u00A0R.J.\u00C2\u00A0Goldfarb,\u00C2\u00A0and\u00C2\u00A0J.P.\u00C2\u00A0Richards.\u00C2\u00A0\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0Economic\u00C2\u00A0 Geologists,\u00C2\u00A0pp.\u00C2\u00A0111\u00E2\u0080\u0090142.\u00C2\u00A0 \u00C2\u00A0 Hart,\u00C2\u00A0T.R.,\u00C2\u00A0Gibson,\u00C2\u00A0H.L.,\u00C2\u00A0and\u00C2\u00A0Lesher,\u00C2\u00A0C.M.\u00C2\u00A0\u00C2\u00A02004.\u00C2\u00A0\u00C2\u00A0Trace\u00C2\u00A0element\u00C2\u00A0geochemistry\u00C2\u00A0and\u00C2\u00A0petrogenesis\u00C2\u00A0 of\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0rocks\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0volcanogenic\u00C2\u00A0massive\u00C2\u00A0Cu\u00E2\u0080\u0090Zn\u00E2\u0080\u0090Pb\u00C2\u00A0sulfide\u00C2\u00A0deposits.\u00C2\u00A0 Economic\u00C2\u00A0Geology,\u00C2\u00A099:\u00C2\u00A01003\u00E2\u0080\u00901013.\u00C2\u00A0 \u00C2\u00A0 Jones,\u00C2\u00A0P.R.\u00C2\u00A0\u00C2\u00A01981.\u00C2\u00A0\u00C2\u00A0Crustal\u00C2\u00A0structures\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0continental\u00C2\u00A0margin\u00C2\u00A0and\u00C2\u00A0adjacent\u00C2\u00A0Nazca\u00C2\u00A0Plate,\u00C2\u00A09\u00C2\u00A0 degrees\u00C2\u00A0S\u00C2\u00A0latitude.\u00C2\u00A0Geological\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0America,\u00C2\u00A0Memoir\u00C2\u00A0154,\u00C2\u00A0pp.\u00C2\u00A0423\u00E2\u0080\u0093443.\u00C2\u00A0 \u00C2\u00A0 Keller,\u00C2\u00A0R.A.,\u00C2\u00A0Fisk,\u00C2\u00A0M.R.,\u00C2\u00A0Smellie,\u00C2\u00A0J.L.,\u00C2\u00A0Strelin,\u00C2\u00A0J.A.,\u00C2\u00A0Lawver,\u00C2\u00A0L.A.\u00C2\u00A0\u00C2\u00A02002.\u00C2\u00A0\u00C2\u00A0Geochemistry\u00C2\u00A0of\u00C2\u00A0back\u00C2\u00A0arc\u00C2\u00A0 basin\u00C2\u00A0volcanism\u00C2\u00A0in\u00C2\u00A0Bransfield\u00C2\u00A0Strait,\u00C2\u00A0Antarctica;\u00C2\u00A0subducted\u00C2\u00A0contributions\u00C2\u00A0and\u00C2\u00A0along\u00E2\u0080\u0090axis\u00C2\u00A0 variations.\u00C2\u00A0\u00C2\u00A0Journal\u00C2\u00A0of\u00C2\u00A0Geophysical\u00C2\u00A0Research,\u00C2\u00A0107:\u00C2\u00A010.1029/2001,\u00C2\u00A0JB000444,\u00C2\u00A017p.\u00C2\u00A0 \u00C2\u00A0 Large,\u00C2\u00A0R.R.\u00C2\u00A0\u00C2\u00A01992.\u00C2\u00A0\u00C2\u00A0Australian\u00C2\u00A0volcanic\u00E2\u0080\u0090hosted\u00C2\u00A0massive\u00C2\u00A0sulfide\u00C2\u00A0deposits:\u00C2\u00A0Features,\u00C2\u00A0styles,\u00C2\u00A0and\u00C2\u00A0 genetic\u00C2\u00A0models.\u00C2\u00A0\u00C2\u00A0Economic\u00C2\u00A0Geology,\u00C2\u00A087:\u00C2\u00A0471\u00E2\u0080\u0093510.\u00C2\u00A0 \u00C2\u00A0 Lawver,\u00C2\u00A0L.\u00C2\u00A0A.,\u00C2\u00A0Keller,\u00C2\u00A0R.\u00C2\u00A0A.,\u00C2\u00A0Fisk,\u00C2\u00A0M.\u00C2\u00A0R.\u00C2\u00A0and\u00C2\u00A0Strelin,\u00C2\u00A0J.\u00C2\u00A0\u00C2\u00A01995.\u00C2\u00A0\u00C2\u00A0Bransfield\u00C2\u00A0Strait,\u00C2\u00A0Antarctic\u00C2\u00A0Peninsula:\u00C2\u00A0 Active\u00C2\u00A0Extension\u00C2\u00A0Behind\u00C2\u00A0a\u00C2\u00A0Dead\u00C2\u00A0Arc.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0Back\u00E2\u0080\u0090Arc\u00C2\u00A0Basins:\u00C2\u00A0Tectonics\u00C2\u00A0and\u00C2\u00A0Magmatism.\u00C2\u00A0\u00C2\u00A0Edited\u00C2\u00A0 by\u00C2\u00A0B.\u00C2\u00A0Taylor.\u00C2\u00A0\u00C2\u00A0Plenum\u00C2\u00A0Publishing\u00C2\u00A0Corp.,\u00C2\u00A0New\u00C2\u00A0York,\u00C2\u00A0pp.\u00C2\u00A0315\u00E2\u0080\u0093342.\u00C2\u00A0 \u00C2\u00A0 Lentz,\u00C2\u00A0D.R.\u00C2\u00A0\u00C2\u00A01998.\u00C2\u00A0\u00C2\u00A0Petrogenetic\u00C2\u00A0evolution\u00C2\u00A0of\u00C2\u00A0felsic\u00C2\u00A0volcanic\u00C2\u00A0sequences\u00C2\u00A0associated\u00C2\u00A0with\u00C2\u00A0 Phanerozoic\u00C2\u00A0volcanic\u00E2\u0080\u0090hosted\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0systems;\u00C2\u00A0the\u00C2\u00A0role\u00C2\u00A0of\u00C2\u00A0extensional\u00C2\u00A0 geodynamics.\u00C2\u00A0Ore\u00C2\u00A0Geology\u00C2\u00A0Reviews,\u00C2\u00A012:\u00C2\u00A0289\u00E2\u0080\u0090327.\u00C2\u00A0 \u00C2\u00A0 Lydon,\u00C2\u00A0J.W.\u00C2\u00A0\u00C2\u00A01988.\u00C2\u00A0\u00C2\u00A0Volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits,\u00C2\u00A0part\u00C2\u00A02,\u00C2\u00A0genetic\u00C2\u00A0models;\u00C2\u00A0Geoscience\u00C2\u00A0 Canada,\u00C2\u00A015:\u00C2\u00A043\u00E2\u0080\u009065.\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Martinez,\u00C2\u00A0F.,\u00C2\u00A0and\u00C2\u00A0Taylor,\u00C2\u00A0B.\u00C2\u00A0\u00C2\u00A01996.\u00C2\u00A0\u00C2\u00A0Fast\u00C2\u00A0backarc\u00C2\u00A0spreading,\u00C2\u00A0rifting,\u00C2\u00A0and\u00C2\u00A0microplate\u00C2\u00A0rotation,\u00C2\u00A0 between\u00C2\u00A0transform\u00C2\u00A0faults\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Manus\u00C2\u00A0Basin,\u00C2\u00A0Bismarck\u00C2\u00A0Sea.\u00C2\u00A0\u00C2\u00A0Marine\u00C2\u00A0Geophysics\u00C2\u00A0Research,\u00C2\u00A0 18:\u00C2\u00A0\u00C2\u00A0203\u00E2\u0080\u0090224.\u00C2\u00A0 \u00C2\u00A0 Myers,\u00C2\u00A0J.S.\u00C2\u00A0\u00C2\u00A01974.\u00C2\u00A0\u00C2\u00A0Cretaceous\u00C2\u00A0stratigraphy\u00C2\u00A0and\u00C2\u00A0structure,\u00C2\u00A0Western\u00C2\u00A0Andes\u00C2\u00A0of\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0between\u00C2\u00A0 latitudes\u00C2\u00A010o\u00E2\u0080\u009010o30\u001F.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0American\u00C2\u00A0Association\u00C2\u00A0of\u00C2\u00A0Petroleum\u00C2\u00A0Geologists\u00C2\u00A0Bulletin,\u00C2\u00A058:\u00C2\u00A0474\u00E2\u0080\u0090 487.\u00C2\u00A0 \u00C2\u00A0 Ohmoto,\u00C2\u00A0H.\u00C2\u00A0\u00C2\u00A01996.\u00C2\u00A0\u00C2\u00A0Formation\u00C2\u00A0of\u00C2\u00A0volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulfide\u00C2\u00A0deposits:\u00C2\u00A0The\u00C2\u00A0Kuroko\u00C2\u00A0 perspective.\u00C2\u00A0\u00C2\u00A0Ore\u00C2\u00A0Geology\u00C2\u00A0Reviews,\u00C2\u00A010:\u00C2\u00A0135\u00E2\u0080\u0090177.\u00C2\u00A0 \u00C2\u00A0 Piercey,\u00C2\u00A0S.J.\u00C2\u00A0\u00C2\u00A02007.\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0Review\u00C2\u00A0of\u00C2\u00A0Regional\u00E2\u0080\u0090Scale\u00C2\u00A0Lithogeochemical\u00C2\u00A0Methods\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Exploration\u00C2\u00A0for\u00C2\u00A0 Volcanogenic\u00C2\u00A0Massive\u00C2\u00A0Sulfide\u00C2\u00A0(VMS)\u00C2\u00A0Deposits.\u00C2\u00A0\u00C2\u00A0In\u00C2\u00A0Proceedings\u00C2\u00A0of\u00C2\u00A0Exploration\u00C2\u00A007:\u00C2\u00A0Fifth\u00C2\u00A0 Decennial\u00C2\u00A0International\u00C2\u00A0Conference\u00C2\u00A0on\u00C2\u00A0Mineral\u00C2\u00A0Exploration.\u00C2\u00A0\u00C2\u00A0Edited\u00C2\u00A0by\u00C2\u00A0B.\u00C2\u00A0Milkereit.\u00C2\u00A0\u00C2\u00A0 Exploration\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0New\u00C2\u00A0Millennium\u00C2\u00A0,\u00C2\u00A05th\u00C2\u00A0Decennial\u00C2\u00A0International\u00C2\u00A0Conference\u00C2\u00A0on\u00C2\u00A0Mineral\u00C2\u00A0 Exploration,\u00C2\u00A0Toronto,\u00C2\u00A0Canada,\u00C2\u00A0pp.\u00C2\u00A0223\u00E2\u0080\u0090246.\u00C2\u00A0 Chapter\u00C2\u00A06\u00C2\u00A0 Page\u00C2\u00A0207\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 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S.M.\u00C2\u00A0Kay\u00C2\u00A0and\u00C2\u00A0C.W.\u00C2\u00A0Rapela.\u00C2\u00A0\u00C2\u00A0Geological\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0America\u00C2\u00A0Special\u00C2\u00A0Paper\u00C2\u00A0241,\u00C2\u00A0pp.\u00C2\u00A0173\u00E2\u0080\u0090192.\u00C2\u00A0 \u00C2\u00A0 Sillitoe,\u00C2\u00A0R.H.\u00C2\u00A0\u00C2\u00A01982.\u00C2\u00A0\u00C2\u00A0Extensional\u00C2\u00A0habitats\u00C2\u00A0of\u00C2\u00A0rhyolite\u00E2\u0080\u0090hosted\u00C2\u00A0massive\u00C2\u00A0sulfide\u00C2\u00A0deposits.\u00C2\u00A0Geology,\u00C2\u00A0 10:\u00C2\u00A0403\u00E2\u0080\u0090407.\u00C2\u00A0 \u00C2\u00A0 Steinm\u00C3\u00BCller,\u00C2\u00A0K.,\u00C2\u00A0Abad,\u00C2\u00A0N.C.,\u00C2\u00A0and\u00C2\u00A0Grant,\u00C2\u00A0B.\u00C2\u00A0\u00C2\u00A02000.\u00C2\u00A0\u00C2\u00A0Volcanogenic\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0deposits\u00C2\u00A0of\u00C2\u00A0 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machined\u00C2\u00A0Plexiglass\u00C2\u00A0top,\u00C2\u00A0followed\u00C2\u00A0by\u00C2\u00A0conventional\u00C2\u00A0heavy\u00C2\u00A0liquids\u00C2\u00A0and\u00C2\u00A0magnetic\u00C2\u00A0separation\u00C2\u00A0using\u00C2\u00A0 a\u00C2\u00A0Frantz\u00E2\u0084\u00A2\u00C2\u00A0magnetic\u00C2\u00A0separator.\u00C2\u00A0\u00C2\u00A0Samples\u00C2\u00A0were\u00C2\u00A0hand\u00E2\u0080\u0090picked\u00C2\u00A0using\u00C2\u00A0a\u00C2\u00A0binocular\u00C2\u00A0microscope.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Thermal\u00C2\u00A0Ionization\u00C2\u00A0Mass\u00C2\u00A0Spectrometry\u00C2\u00A0(TIMS)\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0analyses\u00C2\u00A0were\u00C2\u00A0done\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A0Pacific\u00C2\u00A0Centre\u00C2\u00A0 for\u00C2\u00A0Isotopic\u00C2\u00A0and\u00C2\u00A0Geochemical\u00C2\u00A0Research\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A0University\u00C2\u00A0of\u00C2\u00A0British\u00C2\u00A0Columbia.\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0methodology\u00C2\u00A0 for\u00C2\u00A0zircon\u00C2\u00A0grain\u00C2\u00A0selection,\u00C2\u00A0abrasion,\u00C2\u00A0dissolution,\u00C2\u00A0geochemical\u00C2\u00A0preparation\u00C2\u00A0and\u00C2\u00A0mass\u00C2\u00A0 spectrometry\u00C2\u00A0are\u00C2\u00A0described\u00C2\u00A0by\u00C2\u00A0Mortensen\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A0(1995).\u00C2\u00A0\u00C2\u00A0All\u00C2\u00A0zircon\u00C2\u00A0fractions\u00C2\u00A0were\u00C2\u00A0air\u00C2\u00A0abraded\u00C2\u00A0 (Krogh,\u00C2\u00A01982)\u00C2\u00A0prior\u00C2\u00A0to\u00C2\u00A0dissolution\u00C2\u00A0to\u00C2\u00A0minimize\u00C2\u00A0the\u00C2\u00A0effects\u00C2\u00A0of\u00C2\u00A0post\u00E2\u0080\u0090crystallization\u00C2\u00A0Pb\u00E2\u0080\u0090loss.\u00C2\u00A0\u00C2\u00A0 Procedural\u00C2\u00A0blanks\u00C2\u00A0for\u00C2\u00A0Pb\u00C2\u00A0and\u00C2\u00A0U\u00C2\u00A0were\u00C2\u00A02\u00C2\u00A0and\u00C2\u00A01\u00C2\u00A0pg,\u00C2\u00A0respectively.\u00C2\u00A0\u00C2\u00A0Analytical\u00C2\u00A0data\u00C2\u00A0are\u00C2\u00A0listed\u00C2\u00A0in\u00C2\u00A0Table\u00C2\u00A0 A1.\u00C2\u00A0\u00C2\u00A0Errors\u00C2\u00A0attached\u00C2\u00A0to\u00C2\u00A0individual\u00C2\u00A0analyses\u00C2\u00A0were\u00C2\u00A0calculated\u00C2\u00A0using\u00C2\u00A0the\u00C2\u00A0numerical\u00C2\u00A0error\u00C2\u00A0 propagation\u00C2\u00A0method\u00C2\u00A0of\u00C2\u00A0Roddick\u00C2\u00A0(1987).\u00C2\u00A0\u00C2\u00A0Decay\u00C2\u00A0constants\u00C2\u00A0used\u00C2\u00A0are\u00C2\u00A0those\u00C2\u00A0recommended\u00C2\u00A0by\u00C2\u00A0 Steiger\u00C2\u00A0and\u00C2\u00A0J\u00C3\u00A4ger\u00C2\u00A0(1975).\u00C2\u00A0\u00C2\u00A0Compositions\u00C2\u00A0for\u00C2\u00A0initial\u00C2\u00A0common\u00C2\u00A0Pb\u00C2\u00A0were\u00C2\u00A0taken\u00C2\u00A0from\u00C2\u00A0the\u00C2\u00A0model\u00C2\u00A0of\u00C2\u00A0 Stacey\u00C2\u00A0and\u00C2\u00A0Kramer\u00C2\u00A0(1975).\u00C2\u00A0All\u00C2\u00A0errors\u00C2\u00A0are\u00C2\u00A0given\u00C2\u00A0at\u00C2\u00A0the\u00C2\u00A02\u00C2\u00A0sigma\u00C2\u00A0level.\u00C2\u00A0 Sensitive\u00C2\u00A0High\u00C2\u00A0Resolution\u00C2\u00A0Ion\u00C2\u00A0Microprobe\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0Reverse\u00C2\u00A0Geometry\u00C2\u00A0(SHRIMP)\u00C2\u00A0analysis\u00C2\u00A0was\u00C2\u00A0carried\u00C2\u00A0 out\u00C2\u00A0Stanford\u00C2\u00A0University,\u00C2\u00A0Stanford,\u00C2\u00A0California.\u00C2\u00A0\u00C2\u00A0All\u00C2\u00A0samples\u00C2\u00A0were\u00C2\u00A0embedded\u00C2\u00A0in\u00C2\u00A025.4\u00C2\u00A0mm\u00C2\u00A0epoxy\u00C2\u00A0 rounds.\u00C2\u00A0\u00C2\u00A0Morphology\u00C2\u00A0and\u00C2\u00A0internal\u00C2\u00A0structure\u00C2\u00A0was\u00C2\u00A0examined\u00C2\u00A0by\u00C2\u00A0SEM\u00C2\u00A0using\u00C2\u00A0both\u00C2\u00A0BSE\u00C2\u00A0imaging\u00C2\u00A0and\u00C2\u00A0 cathodoluminescence\u00C2\u00A0to\u00C2\u00A0view\u00C2\u00A0polished\u00C2\u00A0grain\u00C2\u00A0mounts\u00C2\u00A0(Fig.\u00C2\u00A0A1).\u00C2\u00A0\u00C2\u00A0Data\u00C2\u00A0is\u00C2\u00A0presented\u00C2\u00A0in\u00C2\u00A0table\u00C2\u00A0A2.\u00C2\u00A0 Appendix\u00C2\u00A0A\u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A0210\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0A1.\u00C2\u00A0\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0zircon\u00C2\u00A0analytical\u00C2\u00A0data\u00C2\u00A0obtained\u00C2\u00A0using\u00C2\u00A0ID\u00E2\u0080\u0090TIMS\u00C2\u00A0method.\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Sample\u00C2\u00A0 Description 1\u00C2\u00A0 \u00C2\u00A0 Wt\u00C2\u00A0 (mg)\u00C2\u00A0 U\u00C2\u00A0 (ppm)\u00C2\u00A0 Pb 2 \u00C2\u00A0 (ppm)\u00C2\u00A0 206Pb/204Pb\u00C2\u00A0 (meas.) 3 \u00C2\u00A0 total\u00C2\u00A0 common\u00C2\u00A0 Pb\u00C2\u00A0(pg)\u00C2\u00A0 %\u00C2\u00A0 208Pb 2\u00C2\u00A0 206Pb/238U 4 \u00C2\u00A0 (\u00C2\u00B1\u00C2\u00A0%\u00C2\u00A01\u00CF\u0083\u00C2\u00A0)\u00C2\u00A0 207Pb/235U 4 \u00C2\u00A0 (\u00C2\u00B1\u00C2\u00A0%\u00C2\u00A01\u00CF\u0083\u00C2\u00A0)\u00C2\u00A0 207Pb/206Pb 4 \u00C2\u00A0 (\u00C2\u00B1\u00C2\u00A0%\u00C2\u00A01\u00CF\u0083\u00C2\u00A0)\u00C2\u00A0 206Pb/238U\u00C2\u00A0age\u00C2\u00A0 (Ma;\u00C2\u00A0\u00C2\u00B1\u00C2\u00A0%\u00C2\u00A02\u00C2\u00A0\u00CF\u0083)\u00C2\u00A0 207Pb/206Pb\u00C2\u00A0age\u00C2\u00A0 (Ma;\u00C2\u00A0\u00C2\u00B1\u00C2\u00A0%\u00C2\u00A02\u00CF\u0083\u00C2\u00A0)\u00C2\u00A0 Sample\u00C2\u00A099TG\u00E2\u0080\u00901\u00C2\u00A0 A:\u00C2\u00A0N2,+74\u00C2\u00A0 B:\u00C2\u00A0N2,+74\u00C2\u00A0 C:\u00C2\u00A0N2,+74\u00C2\u00A0 D:\u00C2\u00A0N2,+74\u00C2\u00A0 E:\u00C2\u00A0N2,+74\u00C2\u00A0 0.021\u00C2\u00A0 0.023\u00C2\u00A0 0.024\u00C2\u00A0 0.023\u00C2\u00A0 0.039\u00C2\u00A0 334\u00C2\u00A0 270\u00C2\u00A0 271\u00C2\u00A0 98\u00C2\u00A0 231\u00C2\u00A0 5.5\u00C2\u00A0 4.3\u00C2\u00A0 4.5\u00C2\u00A0 1.6\u00C2\u00A0 3.7\u00C2\u00A0 1653\u00C2\u00A0 909\u00C2\u00A0 385\u00C2\u00A0 624\u00C2\u00A0 1006\u00C2\u00A0 4\u00C2\u00A0 7\u00C2\u00A0 17\u00C2\u00A0 4\u00C2\u00A0 9\u00C2\u00A0 13.9\u00C2\u00A0 12.5\u00C2\u00A0 14.0\u00C2\u00A0 13.9\u00C2\u00A0 12.9\u00C2\u00A0 0.01567(0.23)\u00C2\u00A0 0.01553(0.42)\u00C2\u00A0 0.01587(0.22)\u00C2\u00A0 0.01566(0.38)\u00C2\u00A0 0.01569(0.16)\u00C2\u00A0 0.1043(0.50)\u00C2\u00A0 0.1028(0.57)\u00C2\u00A0 0.1090(0.73)\u00C2\u00A0 0.1085(1.24)\u00C2\u00A0 0.1040(1.00)\u00C2\u00A0 0.04826(0.42)\u00C2\u00A0 0.04799(0.66)\u00C2\u00A0 0.049840.62)\u00C2\u00A0 0.05029(1.17)\u00C2\u00A0 0.04805(0.96)\u00C2\u00A0 100.2(0.5)\u00C2\u00A0 99.3(0.8)\u00C2\u00A0 101.5(0.4)\u00C2\u00A0 100.2(0.8)\u00C2\u00A0 100.4(0.3)\u00C2\u00A0 112.0(20.0)\u00C2\u00A0 98.8(31.1)\u00C2\u00A0 187.4(28.9)\u00C2\u00A0 208.4(54.3)\u00C2\u00A0 101.8(45.6)\u00C2\u00A0 Sample\u00C2\u00A0LW\u00E2\u0080\u0090010\u00C2\u00A0 A:\u00C2\u00A0N1,74\u00E2\u0080\u0090104\u00C2\u00A0 C:\u00C2\u00A0N1,\u00E2\u0080\u009074\u00C2\u00A0 D:\u00C2\u00A0N1,\u00E2\u0080\u009074\u00C2\u00A0 E:\u00C2\u00A0N1,\u00E2\u0080\u009074\u00C2\u00A0 0.032\u00C2\u00A0 0.027\u00C2\u00A0 0.028\u00C2\u00A0 0.032\u00C2\u00A0 280\u00C2\u00A0 404\u00C2\u00A0 295\u00C2\u00A0 294\u00C2\u00A0 4.4\u00C2\u00A0 6.5\u00C2\u00A0 4.7\u00C2\u00A0 4.6\u00C2\u00A0 843\u00C2\u00A0 570\u00C2\u00A0 698\u00C2\u00A0 749\u00C2\u00A0 10\u00C2\u00A0 18\u00C2\u00A0 11\u00C2\u00A0 12\u00C2\u00A0 13.1\u00C2\u00A0 14.7\u00C2\u00A0 14.2\u00C2\u00A0 13.8\u00C2\u00A0 0.01514(0.13)\u00C2\u00A0 0.01518(0.15)\u00C2\u00A0 0.01516(0.13)\u00C2\u00A0 0.01510(0.12)\u00C2\u00A0 0.1001(0.68)\u00C2\u00A0 0.1004(1.50)\u00C2\u00A0 0.1002(1.03)\u00C2\u00A0 0.0998(0.57)\u00C2\u00A0 0.04795(0.62)\u00C2\u00A0 0.04797(1.43)\u00C2\u00A0 0.04796(0.98)\u00C2\u00A0 0.04794(0.51)\u00C2\u00A0 96.9(0.3)\u00C2\u00A0 97.1(0.3)\u00C2\u00A0 97.0(0.3)\u00C2\u00A0 96.6(0.2)\u00C2\u00A0 96.8(29.5)\u00C2\u00A0 97.5(67.9)\u00C2\u00A0 97.3(46.2)\u00C2\u00A0 96.5(24.2)\u00C2\u00A0 Sample\u00C2\u00A0LW\u00E2\u0080\u0090077\u00C2\u00A0 A:\u00C2\u00A0N2,+74\u00C2\u00A0 B:\u00C2\u00A0N2,\u00E2\u0080\u009074\u00C2\u00A0 C:\u00C2\u00A0N2,\u00E2\u0080\u009074\u00C2\u00A0 D:\u00C2\u00A0N2,\u00E2\u0080\u009074\u00C2\u00A0 E:\u00C2\u00A0N2,\u00E2\u0080\u009074\u00C2\u00A0 F:\u00C2\u00A0N2,\u00E2\u0080\u009074\u00C2\u00A0 0.043\u00C2\u00A0 0.018\u00C2\u00A0 0.048\u00C2\u00A0 0.053\u00C2\u00A0 0.068\u00C2\u00A0 0.055\u00C2\u00A0 294\u00C2\u00A0 371\u00C2\u00A0 334\u00C2\u00A0 361\u00C2\u00A0 443\u00C2\u00A0 401\u00C2\u00A0 4.4\u00C2\u00A0 6.0\u00C2\u00A0 5.2\u00C2\u00A0 5.6\u00C2\u00A0 6.8\u00C2\u00A0 6.1\u00C2\u00A0 459\u00C2\u00A0 336\u00C2\u00A0 1139\u00C2\u00A0 405\u00C2\u00A0 642\u00C2\u00A0 915\u00C2\u00A0 25\u00C2\u00A0 19\u00C2\u00A0 13\u00C2\u00A0 44\u00C2\u00A0 42\u00C2\u00A0 22\u00C2\u00A0 14.2\u00C2\u00A0 16.7\u00C2\u00A0 15.1\u00C2\u00A0 14.8\u00C2\u00A0 15.1\u00C2\u00A0 14.6\u00C2\u00A0 0.01422(0.22)\u00C2\u00A0 0.01483(0.26)\u00C2\u00A0 0.01457(0.19)\u00C2\u00A0 0.01470(0.18)\u00C2\u00A0 0.01442(0.13)\u00C2\u00A0 0.01452(0.12)\u00C2\u00A0 0.0938(2.30)\u00C2\u00A0 0.0974(0.87)\u00C2\u00A0 0.0961(0.37)\u00C2\u00A0 0.0972(1.29)\u00C2\u00A0 0.0952(1.33)\u00C2\u00A0 0.0958(0.78)\u00C2\u00A0 0.04783(2.19)\u00C2\u00A0 0.04764(0.75)\u00C2\u00A0 0.04781(0.29)\u00C2\u00A0 0.04795(1.21)\u00C2\u00A0 0.04788(1.27)\u00C2\u00A0 0.04786(0.74)\u00C2\u00A0 91.1(0.4)\u00C2\u00A0 94.9(0.5)\u00C2\u00A0 93.3(0.4)\u00C2\u00A0 94.1(0.3)\u00C2\u00A0 92.3(0.2)\u00C2\u00A0 92.9(0.2)\u00C2\u00A0 91.0(105.5)\u00C2\u00A0 81.5(35.6)\u00C2\u00A0 89.8(13.4)\u00C2\u00A0 96.6(57.2)\u00C2\u00A0 93.3(60.6)\u00C2\u00A0 92.4(35.0)\u00C2\u00A0 Sample\u00C2\u00A0LW\u00E2\u0080\u0090086\u00C2\u00A0 A:\u00C2\u00A0N2,+74\u00C2\u00A0 B:\u00C2\u00A0N2,+74\u00C2\u00A0 C:\u00C2\u00A0N2,+74\u00C2\u00A0 D:\u00C2\u00A0N2,+104\u00C2\u00A0 E:\u00C2\u00A0N2,+74\u00C2\u00A0 F:\u00C2\u00A0N2,+74\u00C2\u00A0 0.044\u00C2\u00A0 0.043\u00C2\u00A0 0.058\u00C2\u00A0 0.048\u00C2\u00A0 0.015\u00C2\u00A0 0.017\u00C2\u00A0 531\u00C2\u00A0 441\u00C2\u00A0 432\u00C2\u00A0 306\u00C2\u00A0 631\u00C2\u00A0 392\u00C2\u00A0 8.6\u00C2\u00A0 7.3\u00C2\u00A0 7.0\u00C2\u00A0 4.9\u00C2\u00A0 10.3\u00C2\u00A0 6.3\u00C2\u00A0 1189\u00C2\u00A0 1750\u00C2\u00A0 1274\u00C2\u00A0 1150\u00C2\u00A0 825\u00C2\u00A0 318\u00C2\u00A0 19\u00C2\u00A0 10\u00C2\u00A0 19\u00C2\u00A0 12\u00C2\u00A0 11\u00C2\u00A0 20\u00C2\u00A0 14.9\u00C2\u00A0 15.1\u00C2\u00A0 13.9\u00C2\u00A0 11.3\u00C2\u00A0 15.1\u00C2\u00A0 15.4\u00C2\u00A0 0.01534(0.13)\u00C2\u00A0 0.01553(0.13)\u00C2\u00A0 0.01551(0.14)\u00C2\u00A0 0.01562(0.13)\u00C2\u00A0 0.01540(0.28)\u00C2\u00A0 0.01502(0.24)\u00C2\u00A0 0.1034(0.86)\u00C2\u00A0 0.1027(0.60)\u00C2\u00A0 0.1027(0.81)\u00C2\u00A0 0.1053(0.31)\u00C2\u00A0 0.1013(0.61)\u00C2\u00A0 0.0993(2.91)\u00C2\u00A0 0.04889(0.82)\u00C2\u00A0 0.04794(0.56)\u00C2\u00A0 0.04802(0.77)\u00C2\u00A0 0.04888(0.24)\u00C2\u00A0 0.04771(0.50)\u00C2\u00A0 0.04795(2.79)\u00C2\u00A0 98.1(0.3)\u00C2\u00A0 99.3(0.3)\u00C2\u00A0 99.2(0.3)\u00C2\u00A0 99.9(0.3)\u00C2\u00A0 98.5(0.5)\u00C2\u00A0 96.1(0.5)\u00C2\u00A0 142.7(38.3)\u00C2\u00A0 96.5(26.4)\u00C2\u00A0 100.1(36.2)\u00C2\u00A0 141.9(11.4)\u00C2\u00A0 84.8(23.8)\u00C2\u00A0 96.7(132.4)\u00C2\u00A0 Sample\u00C2\u00A0LW\u00E2\u0080\u0090151\u00C2\u00A0 A:\u00C2\u00A0N2,+74\u00C2\u00A0 B:\u00C2\u00A0N2,+104\u00C2\u00A0 C:\u00C2\u00A0N2,<74\u00C2\u00A0 0.018\u00C2\u00A0 0.052\u00C2\u00A0 0.060\u00C2\u00A0 489\u00C2\u00A0 486\u00C2\u00A0 303\u00C2\u00A0 10.8\u00C2\u00A0 5.8\u00C2\u00A0 19.0\u00C2\u00A0 2583\u00C2\u00A0 1417\u00C2\u00A0 1005\u00C2\u00A0 4\u00C2\u00A0 13\u00C2\u00A0 67\u00C2\u00A0 14.2\u00C2\u00A0 13.7\u00C2\u00A0 11.0\u00C2\u00A0 0.02069(0.19)\u00C2\u00A0 0.01147(0.18)\u00C2\u00A0 0.05982(0.14)\u00C2\u00A0 0.1808(0.29)\u00C2\u00A0 0.0785(0.39)\u00C2\u00A0 0.7176(0.28)\u00C2\u00A0 0.06337(0.21)\u00C2\u00A0 0.04963(0.33)\u00C2\u00A0 0.08700(0.20)\u00C2\u00A0 132.0(0.5)\u00C2\u00A0 73.5(0.3)\u00C2\u00A0 374.5(1.0)\u00C2\u00A0 720.8(8.8)\u00C2\u00A0 177.5(15.2)\u00C2\u00A0 1360.5(7.6)\u00C2\u00A0 \u00C2\u00A0 1 \u00C2\u00A0N1,N2\u00C2\u00A0=\u00C2\u00A0non\u00E2\u0080\u0090magnetic\u00C2\u00A0at\u00C2\u00A0n\u00C2\u00A0degrees\u00C2\u00A0side\u00C2\u00A0slope\u00C2\u00A0on\u00C2\u00A0Frantz\u00C2\u00A0magnetic\u00C2\u00A0separator;\u00C2\u00A0grain\u00C2\u00A0size\u00C2\u00A0given\u00C2\u00A0in\u00C2\u00A0microns.\u00C2\u00A0 2 \u00C2\u00A0radiogenic\u00C2\u00A0Pb;\u00C2\u00A0corrected\u00C2\u00A0for\u00C2\u00A0blank,\u00C2\u00A0initial\u00C2\u00A0common\u00C2\u00A0Pb,\u00C2\u00A0and\u00C2\u00A0spike\u00C2\u00A0 3 \u00C2\u00A0corrected\u00C2\u00A0for\u00C2\u00A0spike\u00C2\u00A0and\u00C2\u00A0fractionation\u00C2\u00A0 4 \u00C2\u00A0corrected\u00C2\u00A0for\u00C2\u00A0blank\u00C2\u00A0Pb\u00C2\u00A0and\u00C2\u00A0U,\u00C2\u00A0and\u00C2\u00A0common\u00C2\u00A0Pb\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0A\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A0211\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0A2.\u00C2\u00A0\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0zircon\u00C2\u00A0analytical\u00C2\u00A0data\u00C2\u00A0obtained\u00C2\u00A0using\u00C2\u00A0the\u00C2\u00A0SHRIMP\u00E2\u0080\u0090RG\u00C2\u00A0method.\u00C2\u00A0 Spot\u00C2\u00A0 Name\u00C2\u00A0 Meas\u00C2\u00A0 204Pb/\u00C2\u00A0 206Pb\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 Meas\u00C2\u00A0 207Pb/\u00C2\u00A0 206Pb\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 Meas\u00C2\u00A0 208Pb /\u00C2\u00A0 206Pb\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 Th\u00C2\u00A0 ppm\u00C2\u00A0 U\u00C2\u00A0 ppm\u00C2\u00A0 232Th /238U\u00C2\u00A0 Corr\u00C2\u00A0 206Pb /238U\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 Rad\u00C2\u00A0 206Pb\u00C2\u00A0 (ppm)\u00C2\u00A0 207\u00C2\u00A0 corr\u00C2\u00A0 206Pb\u00C2\u00A0 /238U\u00C2\u00A0 Age\u00C2\u00A0 1\u00CF\u0083\u00C2\u00A0 err\u00C2\u00A0 204\u00C2\u00A0 corr\u00C2\u00A0 207Pb\u00C2\u00A0 /206Pb\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 204\u00C2\u00A0 corr\u00C2\u00A0 207Pb /235U\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 204\u00C2\u00A0 corr\u00C2\u00A0 206Pb /238U\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 err\u00C2\u00A0 corr\u00C2\u00A0 TG1\u00E2\u0080\u0090136\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0dacite\u00C2\u00A0pebble\u00C2\u00A0breccias\u00C2\u00A0 1.1*\u00C2\u00A0 0.001146\u00C2\u00A0 65\u00C2\u00A0 .053\u00C2\u00A0 6.2\u00C2\u00A0 .082\u00C2\u00A0 8.9\u00C2\u00A0 39\u00C2\u00A0 129\u00C2\u00A0 0.26\u00C2\u00A0 .016\u00C2\u00A0 2.1\u00C2\u00A0 2.1\u00C2\u00A0 100.9\u00C2\u00A0 2.1\u00C2\u00A0 .0358\u00C2\u00A0 33.5\u00C2\u00A0 0.08\u00C2\u00A0 33.6\u00C2\u00A0 .0156\u00C2\u00A0 2.4\u00C2\u00A0 .073\u00C2\u00A0 2.1*\u00C2\u00A0 0.000000\u00C2\u00A0 0\u00C2\u00A0 .049\u00C2\u00A0 3.8\u00C2\u00A0 .168\u00C2\u00A0 3.0\u00C2\u00A0 158\u00C2\u00A0 287\u00C2\u00A0 0.50\u00C2\u00A0 .016\u00C2\u00A0 1.3\u00C2\u00A0 4.4\u00C2\u00A0 100.1\u00C2\u00A0 1.4\u00C2\u00A0 .0489\u00C2\u00A0 3.8\u00C2\u00A0 0.11\u00C2\u00A0 4.1\u00C2\u00A0 .0157\u00C2\u00A0 1.3\u00C2\u00A0 .330\u00C2\u00A0 3.1*\u00C2\u00A0 0.000453\u00C2\u00A0 47\u00C2\u00A0 .049\u00C2\u00A0 4.3\u00C2\u00A0 .152\u00C2\u00A0 3.6\u00C2\u00A0 117\u00C2\u00A0 227\u00C2\u00A0 0.46\u00C2\u00A0 .016\u00C2\u00A0 1.5\u00C2\u00A0 3.6\u00C2\u00A0 99.8\u00C2\u00A0 1.5\u00C2\u00A0 .0424\u00C2\u00A0 9.3\u00C2\u00A0 0.09\u00C2\u00A0 9.4\u00C2\u00A0 .0155\u00C2\u00A0 1.5\u00C2\u00A0 .163\u00C2\u00A0 4.1\u00C2\u00A0 0.000000\u00C2\u00A0 0\u00C2\u00A0 .050\u00C2\u00A0 4.6\u00C2\u00A0 .141\u00C2\u00A0 3.9\u00C2\u00A0 102\u00C2\u00A0 208\u00C2\u00A0 0.43\u00C2\u00A0 .017\u00C2\u00A0 1.6\u00C2\u00A0 3.5\u00C2\u00A0 106.4\u00C2\u00A0 1.7\u00C2\u00A0 .0500\u00C2\u00A0 4.6\u00C2\u00A0 0.11\u00C2\u00A0 4.8\u00C2\u00A0 .0167\u00C2\u00A0 1.6\u00C2\u00A0 .321\u00C2\u00A0 5.1\u00C2\u00A0 0.000071\u00C2\u00A0 52\u00C2\u00A0 .050\u00C2\u00A0 1.7\u00C2\u00A0 .246\u00C2\u00A0 1.0\u00C2\u00A0 1521\u00C2\u00A0 1807\u00C2\u00A0 0.76\u00C2\u00A0 .016\u00C2\u00A0 0.7\u00C2\u00A0 29.3\u00C2\u00A0 104.8\u00C2\u00A0 0.8\u00C2\u00A0 .0494\u00C2\u00A0 2.1\u00C2\u00A0 0.11\u00C2\u00A0 2.2\u00C2\u00A0 .0164\u00C2\u00A0 0.7\u00C2\u00A0 .334\u00C2\u00A0 6.1\u00C2\u00A0 0.000000\u00C2\u00A0 0\u00C2\u00A0 .051\u00C2\u00A0 3.2\u00C2\u00A0 .263\u00C2\u00A0 1.8\u00C2\u00A0 690\u00C2\u00A0 771\u00C2\u00A0 0.79\u00C2\u00A0 .016\u00C2\u00A0 1.4\u00C2\u00A0 12.5\u00C2\u00A0 103.1\u00C2\u00A0 1.5\u00C2\u00A0 .0506\u00C2\u00A0 3.2\u00C2\u00A0 0.11\u00C2\u00A0 3.5\u00C2\u00A0 .0162\u00C2\u00A0 1.4\u00C2\u00A0 .404\u00C2\u00A0 7.1\u00C2\u00A0 0.000574\u00C2\u00A0 55\u00C2\u00A0 .049\u00C2\u00A0 5.6\u00C2\u00A0 .200\u00C2\u00A0 2.6\u00C2\u00A0 218\u00C2\u00A0 329\u00C2\u00A0 0.58\u00C2\u00A0 .017\u00C2\u00A0 1.1\u00C2\u00A0 5.6\u00C2\u00A0 106.5\u00C2\u00A0 1.2\u00C2\u00A0 .0408\u00C2\u00A0 13.8\u00C2\u00A0 0.09\u00C2\u00A0 13.8\u00C2\u00A0 .0165\u00C2\u00A0 1.2\u00C2\u00A0 .090\u00C2\u00A0 8.1*\u00C2\u00A0 0.000000\u00C2\u00A0 0\u00C2\u00A0 .058\u00C2\u00A0 4.7\u00C2\u00A0 .140\u00C2\u00A0 3.8\u00C2\u00A0 110\u00C2\u00A0 228\u00C2\u00A0 0.43\u00C2\u00A0 .018\u00C2\u00A0 1.3\u00C2\u00A0 4.0\u00C2\u00A0 111.6\u00C2\u00A0 1.5\u00C2\u00A0 .0577\u00C2\u00A0 4.7\u00C2\u00A0 0.14\u00C2\u00A0 4.9\u00C2\u00A0 .0176\u00C2\u00A0 1.3\u00C2\u00A0 .271\u00C2\u00A0 9.1\u00C2\u00A0 0.000120\u00C2\u00A0 49\u00C2\u00A0 .050\u00C2\u00A0 2.7\u00C2\u00A0 .228\u00C2\u00A0 1.6\u00C2\u00A0 611\u00C2\u00A0 769\u00C2\u00A0 0.70\u00C2\u00A0 .016\u00C2\u00A0 0.9\u00C2\u00A0 12.6\u00C2\u00A0 104.1\u00C2\u00A0 0.9\u00C2\u00A0 .0487\u00C2\u00A0 3.3\u00C2\u00A0 0.11\u00C2\u00A0 3.5\u00C2\u00A0 .0163\u00C2\u00A0 0.9\u00C2\u00A0 .256\u00C2\u00A0 10.1\u00C2\u00A0 0.000291\u00C2\u00A0 49\u00C2\u00A0 .051\u00C2\u00A0 4.2\u00C2\u00A0 .148\u00C2\u00A0 3.1\u00C2\u00A0 153\u00C2\u00A0 309\u00C2\u00A0 0.44\u00C2\u00A0 .017\u00C2\u00A0 1.7\u00C2\u00A0 5.3\u00C2\u00A0 108.4\u00C2\u00A0 1.8\u00C2\u00A0 .0469\u00C2\u00A0 6.6\u00C2\u00A0 0.11\u00C2\u00A0 6.8\u00C2\u00A0 .0169\u00C2\u00A0 1.7\u00C2\u00A0 .247\u00C2\u00A0 11.1\u00C2\u00A0 0.000000\u00C2\u00A0 0\u00C2\u00A0 .045\u00C2\u00A0 5.3\u00C2\u00A0 .114\u00C2\u00A0 4.9\u00C2\u00A0 88\u00C2\u00A0 232\u00C2\u00A0 0.34\u00C2\u00A0 .016\u00C2\u00A0 1.4\u00C2\u00A0 3.7\u00C2\u00A0 102.0\u00C2\u00A0 1.5\u00C2\u00A0 .0452\u00C2\u00A0 5.3\u00C2\u00A0 0.10\u00C2\u00A0 5.5\u00C2\u00A0 .0159\u00C2\u00A0 1.4\u00C2\u00A0 .261\u00C2\u00A0 12.1\u00C2\u00A0 0.000703\u00C2\u00A0 56\u00C2\u00A0 .049\u00C2\u00A0 5.0\u00C2\u00A0 .141\u00C2\u00A0 7.7\u00C2\u00A0 119\u00C2\u00A0 253\u00C2\u00A0 0.42\u00C2\u00A0 .016\u00C2\u00A0 1.3\u00C2\u00A0 4.2\u00C2\u00A0 104.6\u00C2\u00A0 1.4\u00C2\u00A0 .0386\u00C2\u00A0 17.1\u00C2\u00A0 0.09\u00C2\u00A0 17.2\u00C2\u00A0 .0162\u00C2\u00A0 1.5\u00C2\u00A0 .086\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 LW\u00E2\u0080\u0090016\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0rhyolite\u00C2\u00A0quartz\u00C2\u00A0porphyry\u00C2\u00A0dyke\u00C2\u00A0 1 64\u00C2\u00A0 .048\u00C2\u00A0 4.6\u00C2\u00A0 .215\u00C2\u00A0 2.9\u00C2\u00A0 127\u00C2\u00A0 197\u00C2\u00A0 0.66\u00C2\u00A0 .016\u00C2\u00A0 1.2\u00C2\u00A0 2.8\u00C2\u00A0 105.1\u00C2\u00A0 1.3\u00C2\u00A0 .0522\u00C2\u00A0 7.1\u00C2\u00A0 0.12\u00C2\u00A0 7.2\u00C2\u00A0 .0165\u00C2\u00A0 1.3\u00C2\u00A0 .175\u00C2\u00A0 2*\u00C2\u00A0 0.000329\u00C2\u00A0 38\u00C2\u00A0 .048\u00C2\u00A0 2.9\u00C2\u00A0 .283\u00C2\u00A0 1.7\u00C2\u00A0 417\u00C2\u00A0 495\u00C2\u00A0 0.87\u00C2\u00A0 .017\u00C2\u00A0 0.7\u00C2\u00A0 7.1\u00C2\u00A0 106.9\u00C2\u00A0 0.8\u00C2\u00A0 .0436\u00C2\u00A0 5.4\u00C2\u00A0 0.10\u00C2\u00A0 5.5\u00C2\u00A0 .0166\u00C2\u00A0 0.8\u00C2\u00A0 .142\u00C2\u00A0 3\u00C2\u00A0 0.000922\u00C2\u00A0 27\u00C2\u00A0 .067\u00C2\u00A0 3.8\u00C2\u00A0 .225\u00C2\u00A0 2.8\u00C2\u00A0 133\u00C2\u00A0 237\u00C2\u00A0 0.58\u00C2\u00A0 .016\u00C2\u00A0 1.1\u00C2\u00A0 3.3\u00C2\u00A0 101.1\u00C2\u00A0 1.2\u00C2\u00A0 .0536\u00C2\u00A0 8.5\u00C2\u00A0 0.12\u00C2\u00A0 8.6\u00C2\u00A0 .0159\u00C2\u00A0 1.2\u00C2\u00A0 .141\u00C2\u00A0 4\u00C2\u00A0 0.000127\u00C2\u00A0 40\u00C2\u00A0 .050\u00C2\u00A0 3.1\u00C2\u00A0 .338\u00C2\u00A0 1.7\u00C2\u00A0 483\u00C2\u00A0 483\u00C2\u00A0 1.03\u00C2\u00A0 .016\u00C2\u00A0 0.8\u00C2\u00A0 6.8\u00C2\u00A0 104.2\u00C2\u00A0 0.9\u00C2\u00A0 .0482\u00C2\u00A0 3.6\u00C2\u00A0 0.11\u00C2\u00A0 3.7\u00C2\u00A0 .0163\u00C2\u00A0 0.8\u00C2\u00A0 .221\u00C2\u00A0 5 63\u00C2\u00A0 .067\u00C2\u00A0 6.9\u00C2\u00A0 .231\u00C2\u00A0 4.9\u00C2\u00A0 43\u00C2\u00A0 86\u00C2\u00A0 0.52\u00C2\u00A0 .017\u00C2\u00A0 2.0\u00C2\u00A0 1.2\u00C2\u00A0 103.8\u00C2\u00A0 2.1\u00C2\u00A0 .0782\u00C2\u00A0 10.5\u00C2\u00A0 0.18\u00C2\u00A0 10.7\u00C2\u00A0 .0168\u00C2\u00A0 2.1\u00C2\u00A0 .200\u00C2\u00A0 6\u00C2\u00A0 0.000377\u00C2\u00A0 39\u00C2\u00A0 .052\u00C2\u00A0 4.7\u00C2\u00A0 .181\u00C2\u00A0 3.4\u00C2\u00A0 113\u00C2\u00A0 213\u00C2\u00A0 0.55\u00C2\u00A0 .016\u00C2\u00A0 1.2\u00C2\u00A0 3.0\u00C2\u00A0 103.0\u00C2\u00A0 1.3\u00C2\u00A0 .0466\u00C2\u00A0 7.1\u00C2\u00A0 0.10\u00C2\u00A0 7.2\u00C2\u00A0 .0161\u00C2\u00A0 1.3\u00C2\u00A0 .176\u00C2\u00A0 7\u00C2\u00A0 0.000523\u00C2\u00A0 40\u00C2\u00A0 .049\u00C2\u00A0 4.5\u00C2\u00A0 .190\u00C2\u00A0 3.2\u00C2\u00A0 143\u00C2\u00A0 251\u00C2\u00A0 0.59\u00C2\u00A0 .016\u00C2\u00A0 1.2\u00C2\u00A0 3.5\u00C2\u00A0 104.4\u00C2\u00A0 1.2\u00C2\u00A0 .0416\u00C2\u00A0 9.3\u00C2\u00A0 0.09\u00C2\u00A0 9.4\u00C2\u00A0 .0162\u00C2\u00A0 1.2\u00C2\u00A0 .130\u00C2\u00A0 8 3\u00C2\u00A0 .049\u00C2\u00A0 5.8\u00C2\u00A0 .249\u00C2\u00A0 3.5\u00C2\u00A0 139\u00C2\u00A0 179\u00C2\u00A0 0.80\u00C2\u00A0 .016\u00C2\u00A0 1.5\u00C2\u00A0 2.5\u00C2\u00A0 102.9\u00C2\u00A0 1.5\u00C2\u00A0 .0582\u00C2\u00A0 4.9\u00C2\u00A0 0.13\u00C2\u00A0 5.1\u00C2\u00A0 .0163\u00C2\u00A0 1.5\u00C2\u00A0 .284\u00C2\u00A0 9\u00C2\u00A0 0.000407\u00C2\u00A0 30\u00C2\u00A0 .048\u00C2\u00A0 3.2\u00C2\u00A0 .356\u00C2\u00A0 2.0\u00C2\u00A0 512\u00C2\u00A0 480\u00C2\u00A0 1.10\u00C2\u00A0 .016\u00C2\u00A0 1.0\u00C2\u00A0 6.7\u00C2\u00A0 103.4\u00C2\u00A0 1.0\u00C2\u00A0 .0418\u00C2\u00A0 5.8\u00C2\u00A0 0.09\u00C2\u00A0 5.9\u00C2\u00A0 .0160\u00C2\u00A0 1.0\u00C2\u00A0 .167\u00C2\u00A0 10*\u00C2\u00A0 0.000000\u00C2\u00A0 0\u00C2\u00A0 .050\u00C2\u00A0 2.3\u00C2\u00A0 .414\u00C2\u00A0 1.1\u00C2\u00A0 1219\u00C2\u00A0 986\u00C2\u00A0 1.28\u00C2\u00A0 .017\u00C2\u00A0 0.6\u00C2\u00A0 14.2\u00C2\u00A0 107.0\u00C2\u00A0 0.6\u00C2\u00A0 .0496\u00C2\u00A0 2.3\u00C2\u00A0 0.11\u00C2\u00A0 2.3\u00C2\u00A0 .0168\u00C2\u00A0 0.6\u00C2\u00A0 .250\u00C2\u00A0 11 61\u00C2\u00A0 .049\u00C2\u00A0 12.8\u00C2\u00A0 .147\u00C2\u00A0 8.5\u00C2\u00A0 24\u00C2\u00A0 57\u00C2\u00A0 0.43\u00C2\u00A0 .016\u00C2\u00A0 2.7\u00C2\u00A0 0.8\u00C2\u00A0 100.6\u00C2\u00A0 2.8\u00C2\u00A0 .0498\u00C2\u00A0 12.5\u00C2\u00A0 0.11\u00C2\u00A0 12.8\u00C2\u00A0 .0158\u00C2\u00A0 2.7\u00C2\u00A0 .212\u00C2\u00A0 12 2\u00C2\u00A0 .049\u00C2\u00A0 4.7\u00C2\u00A0 .265\u00C2\u00A0 2.8\u00C2\u00A0 253\u00C2\u00A0 326\u00C2\u00A0 0.80\u00C2\u00A0 .016\u00C2\u00A0 1.2\u00C2\u00A0 4.4\u00C2\u00A0 101.0\u00C2\u00A0 1.2\u00C2\u00A0 .0553\u00C2\u00A0 4.1\u00C2\u00A0 0.12\u00C2\u00A0 4.3\u00C2\u00A0 .0159\u00C2\u00A0 1.2\u00C2\u00A0 .274\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0A\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A0212\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0A2\u00C2\u00A0continued.\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Meas\u00C2\u00A0 204Pb/\u00C2\u00A0 206Pb\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 Meas\u00C2\u00A0 207Pb/\u00C2\u00A0 206Pb\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 Meas\u00C2\u00A0 208Pb /\u00C2\u00A0 206Pb\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 Th\u00C2\u00A0 ppm\u00C2\u00A0 U\u00C2\u00A0 ppm\u00C2\u00A0 232Th\u00C2\u00A0 /238U\u00C2\u00A0 Corr\u00C2\u00A0 206Pb\u00C2\u00A0 /238U\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 Rad\u00C2\u00A0 206Pb\u00C2\u00A0 (ppm)\u00C2\u00A0 207\u00C2\u00A0 corr\u00C2\u00A0 206Pb\u00C2\u00A0 /238U\u00C2\u00A0 Age\u00C2\u00A0 1\u00CF\u0083\u00C2\u00A0 err\u00C2\u00A0 204\u00C2\u00A0 corr\u00C2\u00A0 207Pb\u00C2\u00A0 /206Pb\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 204\u00C2\u00A0 corr\u00C2\u00A0 207Pb\u00C2\u00A0 /235U\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 204\u00C2\u00A0 corr\u00C2\u00A0 206Pb\u00C2\u00A0 /238U\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 err\u00C2\u00A0 corr\u00C2\u00A0 LW\u00E2\u0080\u0090013\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0rhyolite\u00C2\u00A0quartz\u00C2\u00A0porphyry\u00C2\u00A0dyke\u00C2\u00A0 1\u00C2\u00A0 0.000982\u00C2\u00A0 16\u00C2\u00A0 .048\u00C2\u00A0 4.3\u00C2\u00A0 .089\u00C2\u00A0 5.3\u00C2\u00A0 52\u00C2\u00A0 198\u00C2\u00A0 0.27\u00C2\u00A0 .015\u00C2\u00A0 1.5\u00C2\u00A0 2.6\u00C2\u00A0 96.6\u00C2\u00A0 1.4\u00C2\u00A0 .0334\u00C2\u00A0 11.0\u00C2\u00A0 0.07\u00C2\u00A0 11.1\u00C2\u00A0 .0148\u00C2\u00A0 1.5\u00C2\u00A0 .135\u00C2\u00A0 2a\u00C2\u00A0 0.000758\u00C2\u00A0 34\u00C2\u00A0 .047\u00C2\u00A0 3.0\u00C2\u00A0 .174\u00C2\u00A0 2.9\u00C2\u00A0 185\u00C2\u00A0 358\u00C2\u00A0 0.53\u00C2\u00A0 .016\u00C2\u00A0 1.1\u00C2\u00A0 4.9\u00C2\u00A0 102.4\u00C2\u00A0 1.2\u00C2\u00A0 .0352\u00C2\u00A0 12.4\u00C2\u00A0 0.08\u00C2\u00A0 12.4\u00C2\u00A0 .0158\u00C2\u00A0 1.2\u00C2\u00A0 .098\u00C2\u00A0 2b\u00C2\u00A0 0.000661\u00C2\u00A0 38\u00C2\u00A0 .050\u00C2\u00A0 3.0\u00C2\u00A0 .155\u00C2\u00A0 3.2\u00C2\u00A0 150\u00C2\u00A0 343\u00C2\u00A0 0.45\u00C2\u00A0 .015\u00C2\u00A0 1.1\u00C2\u00A0 4.5\u00C2\u00A0 97.8\u00C2\u00A0 1.1\u00C2\u00A0 .0404\u00C2\u00A0 10.5\u00C2\u00A0 0.08\u00C2\u00A0 10.5\u00C2\u00A0 .0151\u00C2\u00A0 1.2\u00C2\u00A0 .116\u00C2\u00A0 3*\u00C2\u00A0 0.001972\u00C2\u00A0 16\u00C2\u00A0 .051\u00C2\u00A0 4.5\u00C2\u00A0 .151\u00C2\u00A0 4.0\u00C2\u00A0 107\u00C2\u00A0 268\u00C2\u00A0 0.41\u00C2\u00A0 .017\u00C2\u00A0 1.4\u00C2\u00A0 3.9\u00C2\u00A0 106.5\u00C2\u00A0 1.6\u00C2\u00A0 .0209\u00C2\u00A0 32.2\u00C2\u00A0 0.05\u00C2\u00A0 32.3\u00C2\u00A0 .0161\u00C2\u00A0 1.6\u00C2\u00A0 .048\u00C2\u00A0 4\u00C2\u00A0 0.000201\u00C2\u00A0 67\u00C2\u00A0 .046\u00C2\u00A0 4.0\u00C2\u00A0 .091\u00C2\u00A0 5.2\u00C2\u00A0 57\u00C2\u00A0 198\u00C2\u00A0 0.30\u00C2\u00A0 .015\u00C2\u00A0 1.5\u00C2\u00A0 2.6\u00C2\u00A0 98.4\u00C2\u00A0 1.5\u00C2\u00A0 .0430\u00C2\u00A0 6.4\u00C2\u00A0 0.09\u00C2\u00A0 6.6\u00C2\u00A0 .0153\u00C2\u00A0 1.5\u00C2\u00A0 .231\u00C2\u00A0 5\u00C2\u00A0 0.000457\u00C2\u00A0 69\u00C2\u00A0 .046\u00C2\u00A0 2.8\u00C2\u00A0 .191\u00C2\u00A0 3.8\u00C2\u00A0 235\u00C2\u00A0 410\u00C2\u00A0 0.59\u00C2\u00A0 .016\u00C2\u00A0 1.2\u00C2\u00A0 5.5\u00C2\u00A0 100.7\u00C2\u00A0 1.2\u00C2\u00A0 .0396\u00C2\u00A0 12.6\u00C2\u00A0 0.09\u00C2\u00A0 12.7\u00C2\u00A0 .0156\u00C2\u00A0 1.3\u00C2\u00A0 .104\u00C2\u00A0 6\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 108\u00C2\u00A0 .049\u00C2\u00A0 1.7\u00C2\u00A0 .171\u00C2\u00A0 2.1\u00C2\u00A0 590\u00C2\u00A0 1160\u00C2\u00A0 0.53\u00C2\u00A0 .016\u00C2\u00A0 0.6\u00C2\u00A0 15.5\u00C2\u00A0 99.5\u00C2\u00A0 0.6\u00C2\u00A0 .0493\u00C2\u00A0 1.9\u00C2\u00A0 0.11\u00C2\u00A0 2.0\u00C2\u00A0 .0156\u00C2\u00A0 0.6\u00C2\u00A0 .318\u00C2\u00A0 7\u00C2\u00A0 0.012278\u00C2\u00A0 9\u00C2\u00A0 .235\u00C2\u00A0 3.9\u00C2\u00A0 .601\u00C2\u00A0 4.5\u00C2\u00A0 120\u00C2\u00A0 273\u00C2\u00A0 0.46\u00C2\u00A0 .020\u00C2\u00A0 1.1\u00C2\u00A0 4.7\u00C2\u00A0 98.5\u00C2\u00A0 4.0\u00C2\u00A0 .0566\u00C2\u00A0 65.8\u00C2\u00A0 0.12\u00C2\u00A0 65.8\u00C2\u00A0 .0156\u00C2\u00A0 2.8\u00C2\u00A0 .042\u00C2\u00A0 8* 42\u00C2\u00A0 .050\u00C2\u00A0 6.2\u00C2\u00A0 .135\u00C2\u00A0 4.5\u00C2\u00A0 74\u00C2\u00A0 198\u00C2\u00A0 0.39\u00C2\u00A0 .017\u00C2\u00A0 1.7\u00C2\u00A0 2.9\u00C2\u00A0 110.5\u00C2\u00A0 1.9\u00C2\u00A0 .0657\u00C2\u00A0 11.5\u00C2\u00A0 0.16\u00C2\u00A0 11.7\u00C2\u00A0 .0177\u00C2\u00A0 1.9\u00C2\u00A0 .164\u00C2\u00A0 9\u00C2\u00A0 0.001503\u00C2\u00A0 30\u00C2\u00A0 .048\u00C2\u00A0 3.7\u00C2\u00A0 .164\u00C2\u00A0 3.8\u00C2\u00A0 117\u00C2\u00A0 246\u00C2\u00A0 0.49\u00C2\u00A0 .016\u00C2\u00A0 1.4\u00C2\u00A0 3.5\u00C2\u00A0 104.6\u00C2\u00A0 1.5\u00C2\u00A0 .0253\u00C2\u00A0 31.0\u00C2\u00A0 0.06\u00C2\u00A0 31.0\u00C2\u00A0 .0159\u00C2\u00A0 1.6\u00C2\u00A0 .053\u00C2\u00A0 10\u00C2\u00A0 0.001397\u00C2\u00A0 28\u00C2\u00A0 .050\u00C2\u00A0 3.1\u00C2\u00A0 .201\u00C2\u00A0 2.9\u00C2\u00A0 168\u00C2\u00A0 307\u00C2\u00A0 0.56\u00C2\u00A0 .016\u00C2\u00A0 1.2\u00C2\u00A0 4.1\u00C2\u00A0 99.3\u00C2\u00A0 1.2\u00C2\u00A0 .0289\u00C2\u00A0 23.3\u00C2\u00A0 0.06\u00C2\u00A0 23.3\u00C2\u00A0 .0152\u00C2\u00A0 1.4\u00C2\u00A0 .059\u00C2\u00A0 11*\u00C2\u00A0 0.003831\u00C2\u00A0 24\u00C2\u00A0 .066\u00C2\u00A0 3.5\u00C2\u00A0 .156\u00C2\u00A0 4.7\u00C2\u00A0 124\u00C2\u00A0 274\u00C2\u00A0 0.47\u00C2\u00A0 .017\u00C2\u00A0 1.5\u00C2\u00A0 4.1\u00C2\u00A0 108.5\u00C2\u00A0 1.7 .0162\u00C2\u00A0 2.3 LW\u00E2\u0080\u0090078\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0rhyolite\u00C2\u00A0boulder\u00C2\u00A0volcaniclastic\u00C2\u00A0 1*\u00C2\u00A0 0.000814\u00C2\u00A0 32\u00C2\u00A0 .050\u00C2\u00A0 4.6\u00C2\u00A0 .140\u00C2\u00A0 3.7\u00C2\u00A0 89\u00C2\u00A0 216\u00C2\u00A0 0.43\u00C2\u00A0 .015\u00C2\u00A0 1.2\u00C2\u00A0 2.8\u00C2\u00A0 95.4\u00C2\u00A0 1.2\u00C2\u00A0 .0374\u00C2\u00A0 12.5\u00C2\u00A0 0.08\u00C2\u00A0 12.6\u00C2\u00A0 .0147\u00C2\u00A0 1.3\u00C2\u00A0 .103\u00C2\u00A0 2\u00C2\u00A0 0.000802\u00C2\u00A0 27\u00C2\u00A0 .046\u00C2\u00A0 6.3\u00C2\u00A0 .090\u00C2\u00A0 6.0\u00C2\u00A0 34\u00C2\u00A0 125\u00C2\u00A0 0.28\u00C2\u00A0 .016\u00C2\u00A0 1.6\u00C2\u00A0 1.7\u00C2\u00A0 100.4\u00C2\u00A0 1.6\u00C2\u00A0 .0342\u00C2\u00A0 13.2\u00C2\u00A0 0.07\u00C2\u00A0 13.3\u00C2\u00A0 .0154\u00C2\u00A0 1.6\u00C2\u00A0 .122\u00C2\u00A0 3 56\u00C2\u00A0 .052\u00C2\u00A0 5.9\u00C2\u00A0 .128\u00C2\u00A0 5.1\u00C2\u00A0 47\u00C2\u00A0 150\u00C2\u00A0 0.32\u00C2\u00A0 .016\u00C2\u00A0 1.5\u00C2\u00A0 2.0\u00C2\u00A0 99.9\u00C2\u00A0 1.6\u00C2\u00A0 .0666\u00C2\u00A0 13.2\u00C2\u00A0 0.15\u00C2\u00A0 13.3\u00C2\u00A0 .0160\u00C2\u00A0 1.8\u00C2\u00A0 .138\u00C2\u00A0 4\u00C2\u00A0 0.000860\u00C2\u00A0 26\u00C2\u00A0 .058\u00C2\u00A0 4.9\u00C2\u00A0 .139\u00C2\u00A0 4.3\u00C2\u00A0 55\u00C2\u00A0 170\u00C2\u00A0 0.33\u00C2\u00A0 .016\u00C2\u00A0 1.4\u00C2\u00A0 2.3\u00C2\u00A0 98.4\u00C2\u00A0 1.4\u00C2\u00A0 .0450\u00C2\u00A0 10.1\u00C2\u00A0 0.10\u00C2\u00A0 10.2\u00C2\u00A0 .0153\u00C2\u00A0 1.4\u00C2\u00A0 .141\u00C2\u00A0 5 2\u00C2\u00A0 .051\u00C2\u00A0 6.4\u00C2\u00A0 .095\u00C2\u00A0 6.1\u00C2\u00A0 36\u00C2\u00A0 125\u00C2\u00A0 0.29\u00C2\u00A0 .016\u00C2\u00A0 1.6\u00C2\u00A0 1.7\u00C2\u00A0 99.4\u00C2\u00A0 1.7\u00C2\u00A0 .0543\u00C2\u00A0 5.9\u00C2\u00A0 0.12\u00C2\u00A0 6.2\u00C2\u00A0 .0157\u00C2\u00A0 1.6\u00C2\u00A0 .265\u00C2\u00A0 6\u00C2\u00A0 0.000416\u00C2\u00A0 67\u00C2\u00A0 .049\u00C2\u00A0 4.7\u00C2\u00A0 .128\u00C2\u00A0 3.9\u00C2\u00A0 77\u00C2\u00A0 214\u00C2\u00A0 0.37\u00C2\u00A0 .015\u00C2\u00A0 1.2\u00C2\u00A0 2.8\u00C2\u00A0 96.5\u00C2\u00A0 1.2\u00C2\u00A0 .0429\u00C2\u00A0 11.1\u00C2\u00A0 0.09\u00C2\u00A0 11.2\u00C2\u00A0 .0150\u00C2\u00A0 1.3\u00C2\u00A0 .118\u00C2\u00A0 7\u00C2\u00A0 0.000180\u00C2\u00A0 65\u00C2\u00A0 .048\u00C2\u00A0 3.6\u00C2\u00A0 .155\u00C2\u00A0 2.7\u00C2\u00A0 149\u00C2\u00A0 336\u00C2\u00A0 0.46\u00C2\u00A0 .016\u00C2\u00A0 0.9\u00C2\u00A0 4.5\u00C2\u00A0 100.5\u00C2\u00A0 0.9\u00C2\u00A0 .0450\u00C2\u00A0 5.5\u00C2\u00A0 0.10\u00C2\u00A0 5.5\u00C2\u00A0 .0157\u00C2\u00A0 0.9\u00C2\u00A0 .171\u00C2\u00A0 8\u00C2\u00A0 0.000032\u00C2\u00A0 1278\u00C2\u00A0 .059\u00C2\u00A0 6.3\u00C2\u00A0 .089\u00C2\u00A0 6.8\u00C2\u00A0 23\u00C2\u00A0 109\u00C2\u00A0 0.22\u00C2\u00A0 .015\u00C2\u00A0 1.7\u00C2\u00A0 1.4\u00C2\u00A0 97.6\u00C2\u00A0 1.7\u00C2\u00A0 .0585\u00C2\u00A0 11.9\u00C2\u00A0 0.12\u00C2\u00A0 12.1\u00C2\u00A0 .0155\u00C2\u00A0 1.9\u00C2\u00A0 .155\u00C2\u00A0 9\u00C2\u00A0 0.000418\u00C2\u00A0 47\u00C2\u00A0 .049\u00C2\u00A0 3.9\u00C2\u00A0 .133\u00C2\u00A0 3.2\u00C2\u00A0 114\u00C2\u00A0 287\u00C2\u00A0 0.41\u00C2\u00A0 .016\u00C2\u00A0 1.0\u00C2\u00A0 3.8\u00C2\u00A0 99.7\u00C2\u00A0 1.0\u00C2\u00A0 .0428\u00C2\u00A0 8.3\u00C2\u00A0 0.09\u00C2\u00A0 8.4\u00C2\u00A0 .0155\u00C2\u00A0 1.1\u00C2\u00A0 .129\u00C2\u00A0 10\u00C2\u00A0 0.000990\u00C2\u00A0 44\u00C2\u00A0 .050\u00C2\u00A0 5.2\u00C2\u00A0 .144\u00C2\u00A0 4.1\u00C2\u00A0 67\u00C2\u00A0 161\u00C2\u00A0 0.43\u00C2\u00A0 .016\u00C2\u00A0 1.4\u00C2\u00A0 2.1\u00C2\u00A0 99.0\u00C2\u00A0 1.4\u00C2\u00A0 .0348\u00C2\u00A0 20.8\u00C2\u00A0 0.07\u00C2\u00A0 20.8\u00C2\u00A0 .0152\u00C2\u00A0 1.6\u00C2\u00A0 .076\u00C2\u00A0 11 46\u00C2\u00A0 .049\u00C2\u00A0 2.6\u00C2\u00A0 .177\u00C2\u00A0 1.9\u00C2\u00A0 344\u00C2\u00A0 647\u00C2\u00A0 0.55\u00C2\u00A0 .015\u00C2\u00A0 0.7\u00C2\u00A0 8.6\u00C2\u00A0 98.4\u00C2\u00A0 0.7\u00C2\u00A0 .0511\u00C2\u00A0 3.0\u00C2\u00A0 0.11\u00C2\u00A0 3.1\u00C2\u00A0 .0154\u00C2\u00A0 0.7\u00C2\u00A0 .222\u00C2\u00A0 12\u00C2\u00A0 0.001679\u00C2\u00A0 23\u00C2\u00A0 .054\u00C2\u00A0 7.5\u00C2\u00A0 .104\u00C2\u00A0 9.4\u00C2\u00A0 21\u00C2\u00A0 73\u00C2\u00A0 0.29\u00C2\u00A0 .015\u00C2\u00A0 2.0\u00C2\u00A0 1.0\u00C2\u00A0 96.9\u00C2\u00A0 2.0\u00C2\u00A0 .0291\u00C2\u00A0 25.7\u00C2\u00A0 0.06\u00C2\u00A0 25.8\u00C2\u00A0 .0148\u00C2\u00A0 2.1\u00C2\u00A0 .082\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0A\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A0213\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0A2\u00C2\u00A0continued.\u00C2\u00A0 Spot\u00C2\u00A0 Name\u00C2\u00A0 Meas\u00C2\u00A0 204Pb/\u00C2\u00A0 206Pb\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 Meas\u00C2\u00A0 207Pb/\u00C2\u00A0 206Pb\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 Meas\u00C2\u00A0 208Pb /\u00C2\u00A0 206Pb\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 Th\u00C2\u00A0 ppm\u00C2\u00A0 U\u00C2\u00A0 ppm\u00C2\u00A0 232Th\u00C2\u00A0 /238U\u00C2\u00A0 Corr\u00C2\u00A0 206Pb\u00C2\u00A0 /238U\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 Rad\u00C2\u00A0 206Pb\u00C2\u00A0 (ppm)\u00C2\u00A0 207\u00C2\u00A0 corr\u00C2\u00A0 206Pb\u00C2\u00A0 /238U\u00C2\u00A0 Age\u00C2\u00A0 1\u00CF\u0083\u00C2\u00A0 err\u00C2\u00A0 204\u00C2\u00A0 corr\u00C2\u00A0 207Pb\u00C2\u00A0 /206Pb\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 204\u00C2\u00A0 corr\u00C2\u00A0 207Pb\u00C2\u00A0 /235U\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 204\u00C2\u00A0 corr\u00C2\u00A0 206Pb\u00C2\u00A0 /238U\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 err\u00C2\u00A0 corr\u00C2\u00A0 LW\u00E2\u0080\u0090043\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0rhyolite\u00C2\u00A0quartz\u00E2\u0080\u0090feldspar\u00C2\u00A0porphyry\u00C2\u00A0dyke\u00C2\u00A0 1*\u00C2\u00A0 0.001361\u00C2\u00A0 89\u00C2\u00A0 .047\u00C2\u00A0 12.0\u00C2\u00A0 .164\u00C2\u00A0 8.4\u00C2\u00A0 37\u00C2\u00A0 90\u00C2\u00A0 0.42\u00C2\u00A0 .007\u00C2\u00A0 2.7\u00C2\u00A0 0.5\u00C2\u00A0 43.7\u00C2\u00A0 1.2\u00C2\u00A0 .0262\u00C2\u00A0 74.9\u00C2\u00A0 0.02\u00C2\u00A0 75.0\u00C2\u00A0 .0066\u00C2\u00A0 3.5\u00C2\u00A0 .046\u00C2\u00A0 2\u00C2\u00A0 0.000407\u00C2\u00A0 37\u00C2\u00A0 .050\u00C2\u00A0 2.9\u00C2\u00A0 .057\u00C2\u00A0 2.7\u00C2\u00A0 169\u00C2\u00A0 1071\u00C2\u00A0 0.16\u00C2\u00A0 .014\u00C2\u00A0 0.6\u00C2\u00A0 13.3\u00C2\u00A0 92.3\u00C2\u00A0 0.5\u00C2\u00A0 .0435\u00C2\u00A0 6.2\u00C2\u00A0 0.09\u00C2\u00A0 6.3\u00C2\u00A0 .0143\u00C2\u00A0 0.6\u00C2\u00A0 .100\u00C2\u00A0 3\u00C2\u00A0 0.000078\u00C2\u00A0 96\u00C2\u00A0 .048\u00C2\u00A0 2.3\u00C2\u00A0 .053\u00C2\u00A0 2.9\u00C2\u00A0 173\u00C2\u00A0 1109\u00C2\u00A0 0.16\u00C2\u00A0 .014\u00C2\u00A0 0.6\u00C2\u00A0 13.7\u00C2\u00A0 92.0\u00C2\u00A0 0.5\u00C2\u00A0 .0467\u00C2\u00A0 3.3\u00C2\u00A0 0.09\u00C2\u00A0 3.4\u00C2\u00A0 .0144\u00C2\u00A0 0.6\u00C2\u00A0 .177\u00C2\u00A0 4\u00C2\u00A0 0.000215\u00C2\u00A0 53\u00C2\u00A0 .049\u00C2\u00A0 2.3\u00C2\u00A0 .054\u00C2\u00A0 2.9\u00C2\u00A0 177\u00C2\u00A0 1087\u00C2\u00A0 0.17\u00C2\u00A0 .014\u00C2\u00A0 0.6\u00C2\u00A0 13.2\u00C2\u00A0 90.5\u00C2\u00A0 0.5\u00C2\u00A0 .0462\u00C2\u00A0 4.5\u00C2\u00A0 0.09\u00C2\u00A0 4.5\u00C2\u00A0 .0141\u00C2\u00A0 0.6\u00C2\u00A0 .139\u00C2\u00A0 5\u00C2\u00A0 0.000052\u00C2\u00A0 211\u00C2\u00A0 .047\u00C2\u00A0 3.6\u00C2\u00A0 .181\u00C2\u00A0 2.5\u00C2\u00A0 198\u00C2\u00A0 377\u00C2\u00A0 0.54\u00C2\u00A0 .014\u00C2\u00A0 0.9\u00C2\u00A0 4.6\u00C2\u00A0 90.5\u00C2\u00A0 0.8\u00C2\u00A0 .0466\u00C2\u00A0 5.0\u00C2\u00A0 0.09\u00C2\u00A0 5.1\u00C2\u00A0 .0141\u00C2\u00A0 0.9\u00C2\u00A0 .180\u00C2\u00A0 6\u00C2\u00A0 0.001839\u00C2\u00A0 40\u00C2\u00A0 .077\u00C2\u00A0 12.3\u00C2\u00A0 .464\u00C2\u00A0 5.6\u00C2\u00A0 426\u00C2\u00A0 422\u00C2\u00A0 1.04\u00C2\u00A0 .015\u00C2\u00A0 1.0\u00C2\u00A0 5.5\u00C2\u00A0 93.1\u00C2\u00A0 1.5\u00C2\u00A0 .0505\u00C2\u00A0 29.8\u00C2\u00A0 0.10\u00C2\u00A0 29.8\u00C2\u00A0 .0146\u00C2\u00A0 1.7\u00C2\u00A0 .058\u00C2\u00A0 7*\u00C2\u00A0 0.000596\u00C2\u00A0 51\u00C2\u00A0 .053\u00C2\u00A0 4.1\u00C2\u00A0 .211\u00C2\u00A0 2.8\u00C2\u00A0 344\u00C2\u00A0 546\u00C2\u00A0 0.65\u00C2\u00A0 .007\u00C2\u00A0 1.0\u00C2\u00A0 3.5\u00C2\u00A0 47.0\u00C2\u00A0 0.5\u00C2\u00A0 .0440\u00C2\u00A0 11.5\u00C2\u00A0 0.04\u00C2\u00A0 11.6\u00C2\u00A0 .0073\u00C2\u00A0 1.2\u00C2\u00A0 .101\u00C2\u00A0 8\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 91\u00C2\u00A0 .050\u00C2\u00A0 2.1\u00C2\u00A0 .054\u00C2\u00A0 2.7\u00C2\u00A0 174\u00C2\u00A0 1144\u00C2\u00A0 0.16\u00C2\u00A0 .014\u00C2\u00A0 0.6\u00C2\u00A0 14.2\u00C2\u00A0 91.9\u00C2\u00A0 0.5\u00C2\u00A0 .0518\u00C2\u00A0 3.6\u00C2\u00A0 0.10\u00C2\u00A0 3.7\u00C2\u00A0 .0144\u00C2\u00A0 0.6\u00C2\u00A0 .159\u00C2\u00A0 9*\u00C2\u00A0 0.000259\u00C2\u00A0 46\u00C2\u00A0 .050\u00C2\u00A0 1.8\u00C2\u00A0 .077\u00C2\u00A0 2.3\u00C2\u00A0 342\u00C2\u00A0 1586\u00C2\u00A0 0.22\u00C2\u00A0 .015\u00C2\u00A0 0.5\u00C2\u00A0 20.3\u00C2\u00A0 95.2\u00C2\u00A0 0.5\u00C2\u00A0 .0459\u00C2\u00A0 4.3\u00C2\u00A0 0.09\u00C2\u00A0 4.4\u00C2\u00A0 .0148\u00C2\u00A0 0.6\u00C2\u00A0 .132\u00C2\u00A0 10 2\u00C2\u00A0 .047\u00C2\u00A0 3.9\u00C2\u00A0 .150\u00C2\u00A0 2.9\u00C2\u00A0 149\u00C2\u00A0 347\u00C2\u00A0 0.44\u00C2\u00A0 .014\u00C2\u00A0 1.0\u00C2\u00A0 4.2\u00C2\u00A0 89.5\u00C2\u00A0 0.9\u00C2\u00A0 .0525\u00C2\u00A0 3.5\u00C2\u00A0 0.10\u00C2\u00A0 3.7\u00C2\u00A0 .0141\u00C2\u00A0 1.0\u00C2\u00A0 .266\u00C2\u00A0 11\u00C2\u00A0 0.000077\u00C2\u00A0 40\u00C2\u00A0 .049\u00C2\u00A0 2.4\u00C2\u00A0 .049\u00C2\u00A0 3.2\u00C2\u00A0 98\u00C2\u00A0 744\u00C2\u00A0 0.14\u00C2\u00A0 .014\u00C2\u00A0 0.6\u00C2\u00A0 8.9\u00C2\u00A0 89.0\u00C2\u00A0 0.6\u00C2\u00A0 .0480\u00C2\u00A0 2.7\u00C2\u00A0 0.09\u00C2\u00A0 2.8\u00C2\u00A0 .0139\u00C2\u00A0 0.6\u00C2\u00A0 .230\u00C2\u00A0 12\u00C2\u00A0 0.001341\u00C2\u00A0 45\u00C2\u00A0 .046\u00C2\u00A0 6.0\u00C2\u00A0 .129\u00C2\u00A0 4.8\u00C2\u00A0 52\u00C2\u00A0 149\u00C2\u00A0 0.36\u00C2\u00A0 .014\u00C2\u00A0 1.5\u00C2\u00A0 1.8\u00C2\u00A0 91.0\u00C2\u00A0 1.4\u00C2\u00A0 .0257\u00C2\u00A0 38.1\u00C2\u00A0 0.05\u00C2\u00A0 38.1\u00C2\u00A0 .0138\u00C2\u00A0 1.8\u00C2\u00A0 .048\u00C2\u00A0 \u00C2\u00A0 LW\u00E2\u0080\u0090066\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0quartz\u00C2\u00A0porphyritic\u00C2\u00A0rhyolite\u00C2\u00A0breccias\u00C2\u00A0 1 1\u00C2\u00A0 .128\u00C2\u00A0 2.7\u00C2\u00A0 .218\u00C2\u00A0 2.2\u00C2\u00A0 109\u00C2\u00A0 545\u00C2\u00A0 0.44\u00C2\u00A0 .195\u00C2\u00A0 0.7\u00C2\u00A0 43.1\u00C2\u00A0 1079.8\u00C2\u00A0 12.5\u00C2\u00A0 .1276\u00C2\u00A0 2.7\u00C2\u00A0 3.44\u00C2\u00A0 2.7\u00C2\u00A0 .1953\u00C2\u00A0 0.7\u00C2\u00A0 .238\u00C2\u00A0 2\u00C2\u00A0 0.003032\u00C2\u00A0 31\u00C2\u00A0 .091\u00C2\u00A0 3.5\u00C2\u00A0 .223\u00C2\u00A0 3.4\u00C2\u00A0 74\u00C2\u00A0 1484\u00C2\u00A0 0.33\u00C2\u00A0 .016\u00C2\u00A0 1.2\u00C2\u00A0 3.2\u00C2\u00A0 99.6\u00C2\u00A0 1.4\u00C2\u00A0 .0464\u00C2\u00A0 35.0\u00C2\u00A0 0.10\u00C2\u00A0 35.1\u00C2\u00A0 .0155\u00C2\u00A0 2.2\u00C2\u00A0 .062\u00C2\u00A0 3\u00C2\u00A0 0.000481\u00C2\u00A0 48\u00C2\u00A0 .055\u00C2\u00A0 3.9\u00C2\u00A0 .143\u00C2\u00A0 3.7\u00C2\u00A0 127\u00C2\u00A0 710\u00C2\u00A0 0.40\u00C2\u00A0 .016\u00C2\u00A0 1.1\u00C2\u00A0 4.4\u00C2\u00A0 99.8\u00C2\u00A0 1.1\u00C2\u00A0 .0482\u00C2\u00A0 8.7\u00C2\u00A0 0.10\u00C2\u00A0 8.7\u00C2\u00A0 .0156\u00C2\u00A0 1.1\u00C2\u00A0 .131\u00C2\u00A0 4 4\u00C2\u00A0 .045\u00C2\u00A0 10.0\u00C2\u00A0 .182\u00C2\u00A0 7.4\u00C2\u00A0 142\u00C2\u00A0 4113\u00C2\u00A0 0.56\u00C2\u00A0 .004\u00C2\u00A0 2.2\u00C2\u00A0 0.8\u00C2\u00A0 24.1\u00C2\u00A0 0.5\u00C2\u00A0 .0561\u00C2\u00A0 8.4\u00C2\u00A0 0.03\u00C2\u00A0 8.7\u00C2\u00A0 .0038\u00C2\u00A0 2.2\u00C2\u00A0 .251\u00C2\u00A0 5\u00C2\u00A0 0.002298\u00C2\u00A0 31\u00C2\u00A0 .050\u00C2\u00A0 6.8\u00C2\u00A0 .213\u00C2\u00A0 5.2\u00C2\u00A0 416\u00C2\u00A0 264\u00C2\u00A0 0.60\u00C2\u00A0 .002\u00C2\u00A0 1.6\u00C2\u00A0 1.4\u00C2\u00A0 14.4\u00C2\u00A0 0.2\u00C2\u00A0 .0147\u00C2\u00A0 86.7\u00C2\u00A0 0.00\u00C2\u00A0 86.8\u00C2\u00A0 .0022\u00C2\u00A0 2.1\u00C2\u00A0 .024\u00C2\u00A0 6\u00C2\u00A0 0.000029\u00C2\u00A0 67\u00C2\u00A0 .115\u00C2\u00A0 1.2\u00C2\u00A0 .607\u00C2\u00A0 1.1\u00C2\u00A0 149\u00C2\u00A0 230\u00C2\u00A0 2.09\u00C2\u00A0 .342\u00C2\u00A0 1.0\u00C2\u00A0 21.7\u00C2\u00A0 1899.8\u00C2\u00A0 20.3\u00C2\u00A0 .1150\u00C2\u00A0 1.2\u00C2\u00A0 5.43\u00C2\u00A0 1.6\u00C2\u00A0 .3421\u00C2\u00A0 1.0\u00C2\u00A0 .648\u00C2\u00A0 7 51\u00C2\u00A0 .049\u00C2\u00A0 10.4\u00C2\u00A0 .150\u00C2\u00A0 8.9\u00C2\u00A0 241\u00C2\u00A0 328\u00C2\u00A0 0.46\u00C2\u00A0 .002\u00C2\u00A0 2.3\u00C2\u00A0 0.8\u00C2\u00A0 10.4\u00C2\u00A0 0.2\u00C2\u00A0 .0962\u00C2\u00A0 24.8\u00C2\u00A0 0.02\u00C2\u00A0 25.1\u00C2\u00A0 .0017\u00C2\u00A0 3.7\u00C2\u00A0 .149\u00C2\u00A0 8\u00C2\u00A0 0.001324\u00C2\u00A0 24\u00C2\u00A0 .065\u00C2\u00A0 2.5\u00C2\u00A0 .157\u00C2\u00A0 3.1\u00C2\u00A0 1487\u00C2\u00A0 29\u00C2\u00A0 0.37\u00C2\u00A0 .002\u00C2\u00A0 0.7\u00C2\u00A0 8.2\u00C2\u00A0 14.6\u00C2\u00A0 0.1\u00C2\u00A0 .0456\u00C2\u00A0 12.8\u00C2\u00A0 0.01\u00C2\u00A0 12.8\u00C2\u00A0 .0023\u00C2\u00A0 0.9\u00C2\u00A0 .072\u00C2\u00A0 9\u00C2\u00A0 0.000013\u00C2\u00A0 606\u00C2\u00A0 .097\u00C2\u00A0 1.5\u00C2\u00A0 .041\u00C2\u00A0 3.5\u00C2\u00A0 9\u00C2\u00A0 257\u00C2\u00A0 0.14\u00C2\u00A0 .273\u00C2\u00A0 1.1\u00C2\u00A0 15.5\u00C2\u00A0 1554.4\u00C2\u00A0 16.8\u00C2\u00A0 .0969\u00C2\u00A0 1.9\u00C2\u00A0 3.65\u00C2\u00A0 2.2\u00C2\u00A0 .2729\u00C2\u00A0 1.1\u00C2\u00A0 .501\u00C2\u00A0 10\u00C2\u00A0 0.001595\u00C2\u00A0 25\u00C2\u00A0 .095\u00C2\u00A0 2.7\u00C2\u00A0 .166\u00C2\u00A0 3.1\u00C2\u00A0 12\u00C2\u00A0 66\u00C2\u00A0 0.42\u00C2\u00A0 .193\u00C2\u00A0 1.6\u00C2\u00A0 4.8\u00C2\u00A0 1114.5\u00C2\u00A0 18.4\u00C2\u00A0 .0722\u00C2\u00A0 10.0\u00C2\u00A0 1.87\u00C2\u00A0 10.1\u00C2\u00A0 .1876\u00C2\u00A0 1.8\u00C2\u00A0 .179\u00C2\u00A0 11\u00C2\u00A0 0.004730\u00C2\u00A0 22\u00C2\u00A0 .089\u00C2\u00A0 3.7\u00C2\u00A0 .283\u00C2\u00A0 3.2\u00C2\u00A0 739\u00C2\u00A0 74\u00C2\u00A0 0.51\u00C2\u00A0 .002\u00C2\u00A0 1.1\u00C2\u00A0 2.7\u00C2\u00A0 13.0\u00C2\u00A0 0.2 .0019\u00C2\u00A0 2.4 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0A\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A0214\u00C2\u00A0 \u00C2\u00A0Appendix\u00C2\u00A0A\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A0215\u00C2\u00A0 \u00C2\u00A0 Table\u00C2\u00A0A2\u00C2\u00A0continued.\u00C2\u00A0 Spot\u00C2\u00A0 Name\u00C2\u00A0 Meas\u00C2\u00A0 204Pb/\u00C2\u00A0 206Pb\u00C2\u00A0 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172\u00C2\u00A0 523\u00C2\u00A0 0.84\u00C2\u00A0 .100\u00C2\u00A0 0.7\u00C2\u00A0 18.2\u00C2\u00A0 614.4\u00C2\u00A0 4.2\u00C2\u00A0 .0607\u00C2\u00A0 4.1\u00C2\u00A0 0.84\u00C2\u00A0 4.1\u00C2\u00A0 .1001\u00C2\u00A0 0.7\u00C2\u00A0 .172\u00C2\u00A0 2\u00C2\u00A0 0.000043\u00C2\u00A0 35\u00C2\u00A0 .073\u00C2\u00A0 1.1\u00C2\u00A0 .002\u00C2\u00A0 9.5\u00C2\u00A0 3\u00C2\u00A0 495\u00C2\u00A0 0.01\u00C2\u00A0 .158\u00C2\u00A0 0.7\u00C2\u00A0 55.0\u00C2\u00A0 942.7\u00C2\u00A0 6.1\u00C2\u00A0 .0727\u00C2\u00A0 1.2\u00C2\u00A0 1.58\u00C2\u00A0 1.4\u00C2\u00A0 .1579\u00C2\u00A0 0.7\u00C2\u00A0 .483\u00C2\u00A0 3\u00C2\u00A0 0.000016\u00C2\u00A0 67\u00C2\u00A0 .161\u00C2\u00A0 4.7\u00C2\u00A0 .103\u00C2\u00A0 1.4\u00C2\u00A0 47\u00C2\u00A0 207\u00C2\u00A0 0.32\u00C2\u00A0 .454\u00C2\u00A0 1.1\u00C2\u00A0 59.4\u00C2\u00A0 2395.7\u00C2\u00A0 41.7\u00C2\u00A0 .1609\u00C2\u00A0 4.7\u00C2\u00A0 10.08\u00C2\u00A0 4.8\u00C2\u00A0 .4543\u00C2\u00A0 1.1\u00C2\u00A0 .229\u00C2\u00A0 4\u00C2\u00A0 0.000085\u00C2\u00A0 41\u00C2\u00A0 .050\u00C2\u00A0 2.6\u00C2\u00A0 .251\u00C2\u00A0 1.8\u00C2\u00A0 334\u00C2\u00A0 716\u00C2\u00A0 0.76\u00C2\u00A0 .030\u00C2\u00A0 0.7\u00C2\u00A0 11.7\u00C2\u00A0 191.6\u00C2\u00A0 1.4\u00C2\u00A0 .0487\u00C2\u00A0 2.9\u00C2\u00A0 0.20\u00C2\u00A0 3.0\u00C2\u00A0 .0301\u00C2\u00A0 0.7\u00C2\u00A0 .247\u00C2\u00A0 5\u00C2\u00A0 0.000016\u00C2\u00A0 3231\u00C2\u00A0 .052\u00C2\u00A0 10.0\u00C2\u00A0 .141\u00C2\u00A0 7.2\u00C2\u00A0 191\u00C2\u00A0 452\u00C2\u00A0 0.40\u00C2\u00A0 .004\u00C2\u00A0 1.6\u00C2\u00A0 1.7\u00C2\u00A0 25.8\u00C2\u00A0 0.4\u00C2\u00A0 .0515\u00C2\u00A0 18.0\u00C2\u00A0 0.03\u00C2\u00A0 18.1\u00C2\u00A0 .0040\u00C2\u00A0 1.8\u00C2\u00A0 .102\u00C2\u00A0 6\u00C2\u00A0 0.000140\u00C2\u00A0 48\u00C2\u00A0 .051\u00C2\u00A0 2.2\u00C2\u00A0 .234\u00C2\u00A0 1.6\u00C2\u00A0 292\u00C2\u00A0 393\u00C2\u00A0 0.77\u00C2\u00A0 .045\u00C2\u00A0 0.7\u00C2\u00A0 15.3\u00C2\u00A0 284.7\u00C2\u00A0 1.9\u00C2\u00A0 .0494\u00C2\u00A0 3.1\u00C2\u00A0 0.31\u00C2\u00A0 3.2\u00C2\u00A0 .0450\u00C2\u00A0 0.7\u00C2\u00A0 .214\u00C2\u00A0 7\u00C2\u00A0 0.000094\u00C2\u00A0 41\u00C2\u00A0 .071\u00C2\u00A0 1.2\u00C2\u00A0 .100\u00C2\u00A0 1.5\u00C2\u00A0 95\u00C2\u00A0 211\u00C2\u00A0 0.32\u00C2\u00A0 .151\u00C2\u00A0 0.6\u00C2\u00A0 39.9\u00C2\u00A0 906.6\u00C2\u00A0 5.1\u00C2\u00A0 .0692\u00C2\u00A0 1.4\u00C2\u00A0 1.44\u00C2\u00A0 1.6\u00C2\u00A0 .1510\u00C2\u00A0 0.6\u00C2\u00A0 .373\u00C2\u00A0 8\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 4\u00C2\u00A0 .050\u00C2\u00A0 7.9\u00C2\u00A0 .139\u00C2\u00A0 7.7\u00C2\u00A0 83\u00C2\u00A0 307\u00C2\u00A0 0.41\u00C2\u00A0 .007\u00C2\u00A0 1.9\u00C2\u00A0 1.3\u00C2\u00A0 47.2\u00C2\u00A0 0.9\u00C2\u00A0 .0677\u00C2\u00A0 6.8\u00C2\u00A0 0.07\u00C2\u00A0 7.0\u00C2\u00A0 .0075\u00C2\u00A0 1.9\u00C2\u00A0 .265\u00C2\u00A0 9\u00C2\u00A0 0.001478\u00C2\u00A0 28\u00C2\u00A0 .052\u00C2\u00A0 3.1\u00C2\u00A0 .177\u00C2\u00A0 2.6\u00C2\u00A0 349\u00C2\u00A0 405\u00C2\u00A0 0.50\u00C2\u00A0 .014\u00C2\u00A0 0.8\u00C2\u00A0 8.9\u00C2\u00A0 92.2\u00C2\u00A0 0.8\u00C2\u00A0 .0294\u00C2\u00A0 24.6\u00C2\u00A0 0.06\u00C2\u00A0 24.6\u00C2\u00A0 .0141\u00C2\u00A0 1.1\u00C2\u00A0 .045\u00C2\u00A0 10\u00C2\u00A0 0.000047\u00C2\u00A0 46\u00C2\u00A0 .080\u00C2\u00A0 0.9\u00C2\u00A0 .124\u00C2\u00A0 1.1\u00C2\u00A0 115\u00C2\u00A0 294\u00C2\u00A0 0.40\u00C2\u00A0 .196\u00C2\u00A0 0.6\u00C2\u00A0 49.4\u00C2\u00A0 1149.6\u00C2\u00A0 6.3\u00C2\u00A0 .0792\u00C2\u00A0 1.0\u00C2\u00A0 2.13\u00C2\u00A0 1.2\u00C2\u00A0 .1955\u00C2\u00A0 0.6\u00C2\u00A0 .472\u00C2\u00A0 11 4\u00C2\u00A0 .052\u00C2\u00A0 9.5\u00C2\u00A0 .175\u00C2\u00A0 7.9\u00C2\u00A0 241\u00C2\u00A0 152\u00C2\u00A0 0.48\u00C2\u00A0 .002\u00C2\u00A0 2.2\u00C2\u00A0 0.8\u00C2\u00A0 11.8\u00C2\u00A0 0.3\u00C2\u00A0 .0958\u00C2\u00A0 8.0\u00C2\u00A0 0.03\u00C2\u00A0 8.3\u00C2\u00A0 .0019\u00C2\u00A0 2.2\u00C2\u00A0 .266\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 LW\u00E2\u0080\u0090033\u00C2\u00A0\u00E2\u0080\u0090quartz\u00E2\u0080\u0090feldspar\u00C2\u00A0porphyritic\u00C2\u00A0rhyolite\u00C2\u00A0dyke\u00C2\u00A0 1.1\u00C2\u00A0 0.000267\u00C2\u00A0 47\u00C2\u00A0 .047\u00C2\u00A0 3.8\u00C2\u00A0 .075\u00C2\u00A0 4.6\u00C2\u00A0 364\u00C2\u00A0 2097\u00C2\u00A0 0.23\u00C2\u00A0 .003\u00C2\u00A0 0.9\u00C2\u00A0 4.9\u00C2\u00A0 21.8\u00C2\u00A0 0.2\u00C2\u00A0 .0433\u00C2\u00A0 6.1\u00C2\u00A0 0.02\u00C2\u00A0 6.2\u00C2\u00A0 .0034\u00C2\u00A0 0.9\u00C2\u00A0 .148\u00C2\u00A0 1.1\u00C2\u00A0 0.000302\u00C2\u00A0 17\u00C2\u00A0 .183\u00C2\u00A0 0.6\u00C2\u00A0 .142\u00C2\u00A0 1.9\u00C2\u00A0 94\u00C2\u00A0 475\u00C2\u00A0 0.57\u00C2\u00A0 .485\u00C2\u00A0 0.7\u00C2\u00A0 70.7\u00C2\u00A0 2490.6\u00C2\u00A0 24.2\u00C2\u00A0 .1794\u00C2\u00A0 0.8\u00C2\u00A0 11.94\u00C2\u00A0 1.1\u00C2\u00A0 .4827\u00C2\u00A0 0.7\u00C2\u00A0 .676\u00C2\u00A0 2\u00C2\u00A0 0.000082\u00C2\u00A0 52\u00C2\u00A0 .082\u00C2\u00A0 1.1\u00C2\u00A0 .139\u00C2\u00A0 1.3\u00C2\u00A0 86\u00C2\u00A0 1671\u00C2\u00A0 0.45\u00C2\u00A0 .199\u00C2\u00A0 0.7\u00C2\u00A0 33.9\u00C2\u00A0 1167.5\u00C2\u00A0 7.6\u00C2\u00A0 .0804\u00C2\u00A0 1.4\u00C2\u00A0 2.21\u00C2\u00A0 1.6\u00C2\u00A0 .1989\u00C2\u00A0 0.7\u00C2\u00A0 .431\u00C2\u00A0 4\u00C2\u00A0 0.000883\u00C2\u00A0 43\u00C2\u00A0 .052\u00C2\u00A0 5.1\u00C2\u00A0 .126\u00C2\u00A0 5.1\u00C2\u00A0 727\u00C2\u00A0 98\u00C2\u00A0 0.36\u00C2\u00A0 .001\u00C2\u00A0 1.3\u00C2\u00A0 2.5\u00C2\u00A0 9.0\u00C2\u00A0 0.1\u00C2\u00A0 .0393\u00C2\u00A0 16.7\u00C2\u00A0 0.01\u00C2\u00A0 16.8\u00C2\u00A0 .0014\u00C2\u00A0 1.4\u00C2\u00A0 .086\u00C2\u00A0 5\u00C2\u00A0 0.005973\u00C2\u00A0 32\u00C2\u00A0 .086\u00C2\u00A0 9.2\u00C2\u00A0 .183\u00C2\u00A0 5.9\u00C2\u00A0 30\u00C2\u00A0 3219\u00C2\u00A0 0.32\u00C2\u00A0 .016\u00C2\u00A0 1.9\u00C2\u00A0 1.4\u00C2\u00A0 98.2\u00C2\u00A0 2.2 .0144\u00C2\u00A0 4.3 6\u00C2\u00A0 0.033547\u00C2\u00A0 8\u00C2\u00A0 .480\u00C2\u00A0 3.1\u00C2\u00A0 1.264\u00C2\u00A0 3.9\u00C2\u00A0 365\u00C2\u00A0 1689\u00C2\u00A0 0.79\u00C2\u00A0 .008\u00C2\u00A0 1.2\u00C2\u00A0 3.1\u00C2\u00A0 22.8\u00C2\u00A0 3.3 .0030\u00C2\u00A0 15.6 7\u00C2\u00A0 0.000056\u00C2\u00A0 49\u00C2\u00A0 .083\u00C2\u00A0 0.7\u00C2\u00A0 .091\u00C2\u00A0 1.2\u00C2\u00A0 154\u00C2\u00A0 1533\u00C2\u00A0 0.30\u00C2\u00A0 .218\u00C2\u00A0 0.4\u00C2\u00A0 99.6\u00C2\u00A0 1271.5\u00C2\u00A0 5.3\u00C2\u00A0 .0820\u00C2\u00A0 0.8\u00C2\u00A0 2.46\u00C2\u00A0 1.0\u00C2\u00A0 .2177\u00C2\u00A0 0.4\u00C2\u00A0 .447\u00C2\u00A0 10\u00C2\u00A0 0.000037\u00C2\u00A0 78\u00C2\u00A0 .051\u00C2\u00A0 1.1\u00C2\u00A0 .020\u00C2\u00A0 2.7\u00C2\u00A0 94\u00C2\u00A0 156\u00C2\u00A0 0.06\u00C2\u00A0 .037\u00C2\u00A0 0.3\u00C2\u00A0 48.7\u00C2\u00A0 234.0\u00C2\u00A0 0.8\u00C2\u00A0 .0505\u00C2\u00A0 1.4\u00C2\u00A0 0.26\u00C2\u00A0 1.5\u00C2\u00A0 .0369\u00C2\u00A0 0.3\u00C2\u00A0 .235\u00C2\u00A0 11\u00C2\u00A0 0.003089\u00C2\u00A0 5\u00C2\u00A0 .093\u00C2\u00A0 2.9\u00C2\u00A0 .122\u00C2\u00A0 6.1\u00C2\u00A0 314\u00C2\u00A0 98\u00C2\u00A0 0.10\u00C2\u00A0 .030\u00C2\u00A0 0.3\u00C2\u00A0 82.7\u00C2\u00A0 179.9\u00C2\u00A0 1.5\u00C2\u00A0 .0479\u00C2\u00A0 15.7\u00C2\u00A0 0.19\u00C2\u00A0 15.8\u00C2\u00A0 .0282\u00C2\u00A0 0.5\u00C2\u00A0 .033\u00C2\u00A0 12\u00C2\u00A0 0.000089\u00C2\u00A0 16\u00C2\u00A0 .052\u00C2\u00A0 1.2\u00C2\u00A0 .018\u00C2\u00A0 3.1\u00C2\u00A0 82\u00C2\u00A0 198\u00C2\u00A0 0.05\u00C2\u00A0 .036\u00C2\u00A0 0.3\u00C2\u00A0 51.8\u00C2\u00A0 225.8\u00C2\u00A0 0.8\u00C2\u00A0 .0507\u00C2\u00A0 1.3\u00C2\u00A0 0.25\u00C2\u00A0 1.4\u00C2\u00A0 .0357\u00C2\u00A0 0.3\u00C2\u00A0 .250\u00C2\u00A0 13\u00C2\u00A0 0.000091\u00C2\u00A0 35\u00C2\u00A0 .129\u00C2\u00A0 0.7\u00C2\u00A0 .192\u00C2\u00A0 0.9\u00C2\u00A0 132\u00C2\u00A0 532\u00C2\u00A0 0.57\u00C2\u00A0 .252\u00C2\u00A0 0.5\u00C2\u00A0 52.3\u00C2\u00A0 1378.0\u00C2\u00A0 12.1\u00C2\u00A0 .1280\u00C2\u00A0 0.8\u00C2\u00A0 4.44\u00C2\u00A0 1.0\u00C2\u00A0 .2513\u00C2\u00A0 0.5\u00C2\u00A0 .551\u00C2\u00A0 14 1\u00C2\u00A0 .060\u00C2\u00A0 2.5\u00C2\u00A0 .053\u00C2\u00A0 4.0\u00C2\u00A0 15\u00C2\u00A0 242\u00C2\u00A0 0.16\u00C2\u00A0 .097\u00C2\u00A0 1.0\u00C2\u00A0 8.1\u00C2\u00A0 596.5\u00C2\u00A0 5.9\u00C2\u00A0 .0618\u00C2\u00A0 2.5\u00C2\u00A0 0.83\u00C2\u00A0 2.7\u00C2\u00A0 .0972\u00C2\u00A0 1.0\u00C2\u00A0 .372\u00C2\u00A0 15\u00C2\u00A0 0.000128\u00C2\u00A0 86\u00C2\u00A0 .057\u00C2\u00A0 2.5\u00C2\u00A0 .206\u00C2\u00A0 2.0\u00C2\u00A0 99\u00C2\u00A0 170\u00C2\u00A0 0.66\u00C2\u00A0 .066\u00C2\u00A0 0.9\u00C2\u00A0 8.8\u00C2\u00A0 410.3\u00C2\u00A0 3.6\u00C2\u00A0 .0554\u00C2\u00A0 3.9\u00C2\u00A0 0.50\u00C2\u00A0 4.0\u00C2\u00A0 .0658\u00C2\u00A0 0.9\u00C2\u00A0 .223\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0Figure\u00C2\u00A0A1.\u00C2\u00A0\u00C2\u00A0SEM\u00C2\u00A0Cathodoluminesence\u00C2\u00A0images\u00C2\u00A0of\u00C2\u00A0zircons\u00C2\u00A0showing\u00C2\u00A0location\u00C2\u00A0of\u00C2\u00A0spot\u00C2\u00A0analyses\u00C2\u00A0for\u00C2\u00A0 SHRIMP\u00E2\u0080\u0090RG\u00C2\u00A0data.\u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0A\u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A0216\u00C2\u00A0 \u00C2\u00A0Appendix\u00C2\u00A0A\u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A0217\u00C2\u00A0 A.2\u00C2\u00A0 Additional\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0Zircon\u00C2\u00A0Geochronologic\u00C2\u00A0Data\u00C2\u00A0 Sensitive\u00C2\u00A0High\u00C2\u00A0Resolution\u00C2\u00A0Ion\u00C2\u00A0Microprobe\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0Reverse\u00C2\u00A0Geometry\u00C2\u00A0(SHRIMP\u00E2\u0080\u0090RG)\u00C2\u00A0data\u00C2\u00A0are\u00C2\u00A0 provided\u00C2\u00A0here\u00C2\u00A0for\u00C2\u00A04\u00C2\u00A0samples\u00C2\u00A0not\u00C2\u00A0reported\u00C2\u00A0elsewhere\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0thesis.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0Two\u00C2\u00A0samples,\u00C2\u00A0LW\u00E2\u0080\u009030\u00C2\u00A0and\u00C2\u00A0 LW\u00E2\u0080\u009031,\u00C2\u00A0were\u00C2\u00A0collected\u00C2\u00A0by\u00C2\u00A0the\u00C2\u00A0author\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Amotape\u00C2\u00A0range\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0west\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0main\u00C2\u00A0study\u00C2\u00A0area\u00C2\u00A0 (refer\u00C2\u00A0to\u00C2\u00A0Fig.\u00C2\u00A0A2;\u00C2\u00A0locations\u00C2\u00A0and\u00C2\u00A0sample\u00C2\u00A0descriptions\u00C2\u00A0are\u00C2\u00A0given\u00C2\u00A0in\u00C2\u00A0table\u00C2\u00A0A3).\u00C2\u00A0\u00C2\u00A0Samples\u00C2\u00A01601\u00C2\u00A0and\u00C2\u00A0 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.052\u00C2\u00A0 6.7\u00C2\u00A0 .213\u00C2\u00A0 13\u00C2\u00A0 1.7\u00C2\u00A0 1.2\u00C2\u00A0 282\u00C2\u00A0 34.0\u00C2\u00A0 0.05\u00C2\u00A0 34.1\u00C2\u00A0 .0122\u00C2\u00A0 2.0\u00C2\u00A0 .059\u00C2\u00A0 3\u00C2\u00A0 0.000898\u00C2\u00A0 40\u00C2\u00A0 .051\u00C2\u00A0 8.3\u00C2\u00A0 .137\u00C2\u00A0 24\u00C2\u00A0 76\u00C2\u00A0 0.33\u00C2\u00A0 .012\u00C2\u00A0 2.1\u00C2\u00A0 0.8\u00C2\u00A0 78.0\u00C2\u00A0 1.7\u00C2\u00A0 .0378\u00C2\u00A0 18.5\u00C2\u00A0 0.06\u00C2\u00A0 18.7\u00C2\u00A0 .0120\u00C2\u00A0 2.2\u00C2\u00A0 .119\u00C2\u00A0 4\u00C2\u00A0 0.00 4 \u00C2\u00A0 .012\u00C2\u00A0 2.0 \u00C2\u00A0 9\u00C2\u00A0 37.5\u00C2\u00A0 0.05\u00C2\u00A0 37.6\u00C2\u00A0 .0120\u00C2\u00A0 2.3\u00C2\u00A0 .062\u00C2\u00A0 5\u00C2\u00A0 0.000657\u00C2\u00A0 33\u00C2\u00A0 .053\u00C2\u00A0 3.2\u00C2\u00A0 .115\u00C2\u00A0 .012\u00C2\u00A0 0.8\u00C2\u00A0 6.2\u00C2\u00A0 76.2\u00C2\u00A0 0.6\u00C2\u00A0 .0430\u00C2\u00A0 8.6\u00C2\u00A0 0.07\u00C2\u00A0 8.6\u00C2\u00A0 .0118\u00C2\u00A0 0.9\u00C2\u00A0 .105\u00C2\u00A0 6\u00C2\u00A0 0.001168\u00C2\u00A0 43\u00C2\u00A0 .057\u00C2\u00A0 6.4\u00C2\u00A0 .127\u00C2\u00A0 36\u00C2\u00A0 112\u00C2\u00A0 0.33\u00C2\u00A0 .013\u00C2\u00A0 2.0\u00C2\u00A0 1.2\u00C2\u00A0 81.3\u00C2\u00A0 1.7\u00C2\u00A0 .0391\u00C2\u00A0 21.8\u00C2\u00A0 0.07\u00C2\u00A0 21.9\u00C2\u00A0 .0126\u00C2\u00A0 2.2\u00C2\u00A0 .102\u00C2\u00A0 7\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 3\u00C2\u00A0 1.2 \u00C2\u00A0 \u00C2\u00A0 7.2\u00C2\u00A0 0.08\u00C2\u00A0 7.3\u00C2\u00A0 .0126\u00C2\u00A0 1.2\u00C2\u00A0 .168\u00C2\u00A0 8\u00C2\u00A0 \u00E2\u0080\u00900.000647\u00C2\u00A0 54\u00C2\u00A0 .051\u00C2\u00A0 .082\u00C2\u00A0 \u00C2\u00A0 1.1\u00C2\u00A0 3.4\u00C2\u00A0 80.6\u00C2\u00A0 0.9\u00C2\u00A0 .0604\u00C2\u00A0 9.1\u00C2\u00A0 0.11\u00C2\u00A0 9.1\u00C2\u00A0 .0128\u00C2\u00A0 1.2\u00C2\u00A0 .134\u00C2\u00A0 9\u00C2\u00A0 00 6 \u00C2\u00A0 .102\u00C2\u00A0 13\u00C2\u00A0 1.7 \u00C2\u00A0 93\u00C2\u00A0 40.9\u00C2\u00A0 0.05\u00C2\u00A0 41.0\u00C2\u00A0 .0123\u00C2\u00A0 2.2\u00C2\u00A0 .054\u00C2\u00A0 10\u00C2\u00A0 0.000778\u00C2\u00A0 21\u00C2\u00A0 .050\u00C2\u00A0 271\u00C2\u00A0 0.27\u00C2\u00A0 .012\u00C2\u00A0 1.1\u00C2\u00A0 2.9\u00C2\u00A0 78.4\u00C2\u00A0 0.9\u00C2\u00A0 .0381\u00C2\u00A0 9.0\u00C2\u00A0 0.06\u00C2\u00A0 9.1\u00C2\u00A0 .0121\u00C2\u00A0 1.2\u00C2\u00A0 .128\u00C2\u00A0 11\u00C2\u00A0 0.000005\u00C2\u00A0 7280\u00C2\u00A0 .050\u00C2\u00A0 4.6\u00C2\u00A0 .180\u00C2\u00A0 3.2\u00C2\u00A0 134\u00C2\u00A0 258\u00C2\u00A0 0.54\u00C2\u00A0 .013\u00C2\u00A0 1.2\u00C2\u00A0 2.9\u00C2\u00A0 83.6\u00C2\u00A0 1.0\u00C2\u00A0 .0500\u00C2\u00A0 11.1\u00C2\u00A0 0.09\u00C2\u00A0 11.2\u00C2\u00A0 .0131\u00C2\u00A0 1.3\u00C2\u00A0 .118\u00C2\u00A0 1601\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0\"Linderos\u00C2\u00A0Porphyry\"\u00C2\u00A0prospect.\u00C2\u00A0\u00C2\u00A0Granodioritic\u00C2\u00A0porphyry\u00C2\u00A0with\u00C2\u00A0veining.\u00C2\u00A0 1\u00C2\u00A0 0.002663\u00C2\u00A0 48\u00C2\u00A0 .054\u00C2\u00A0 9.2\u00C2\u00A0 .079\u00C2\u00A0 10.2\u00C2\u00A0 11\u00C2\u00A0 52\u00C2\u00A0 0.22\u00C2\u00A0 .014\u00C2\u00A0 2.5\u00C2\u00A0 0.6\u00C2\u00A0 86.1\u00C2\u00A0 2.2\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 .0129\u00C2\u00A0 3.5\u00C2\u00A0 \u00C2\u00A0 2\u00C2\u00A0 0.001124\u00C2\u00A0 67\u00C2\u00A0 .053\u00C2\u00A0 7.9\u00C2\u00A0 .083\u00C2\u00A0 8.4\u00C2\u00A0 13\u00C2\u00A0 71\u00C2\u00A0 0.19\u00C2\u00A0 .014\u00C2\u00A0 2.1\u00C2\u00A0 0.9\u00C2\u00A0 90.5\u00C2\u00A0 2.0\u00C2\u00A0 .0362\u00C2\u00A0 33.9\u00C2\u00A0 0.07\u00C2\u00A0 34.0\u00C2\u00A0 .0139\u00C2\u00A0 2.5\u00C2\u00A0 .074\u00C2\u00A0 3\u00C2\u00A0 0.000000\u00C2\u00A0 0\u00C2\u00A0 .054\u00C2\u00A0 6.0\u00C2\u00A0 .076\u00C2\u00A0 6.6\u00C2\u00A0 24\u00C2\u00A0 125\u00C2\u00A0 0.20\u00C2\u00A0 .014\u00C2\u00A0 1.6\u00C2\u00A0 1.5\u00C2\u00A0 87.2\u00C2\u00A0 1.4\u00C2\u00A0 .0543\u00C2\u00A0 6.0\u00C2\u00A0 0.10\u00C2\u00A0 6.3\u00C2\u00A0 .0137\u00C2\u00A0 1.6\u00C2\u00A0 .258\u00C2\u00A0 4\u00C2\u00A0 \u00E2\u0080\u00900.000769\u00C2\u00A0 3\u00C2\u00A0 .048\u00C2\u00A0 6.2\u00C2\u00A0 .066\u00C2\u00A0 6.8\u00C2\u00A0 26\u00C2\u00A0 138\u00C2\u00A0 0.19\u00C2\u00A0 .014\u00C2\u00A0 1.5\u00C2\u00A0 1.6\u00C2\u00A0 87.9\u00C2\u00A0 1.4\u00C2\u00A0 .0594\u00C2\u00A0 5.1\u00C2\u00A0 0.11\u00C2\u00A0 5.3\u00C2\u00A0 .0139\u00C2\u00A0 1.5\u00C2\u00A0 .285\u00C2\u00A0 5\u00C2\u00A0 0.001286\u00C2\u00A0 66\u00C2\u00A0 .048\u00C2\u00A0 8.4\u00C2\u00A0 .101\u00C2\u00A0 7.9\u00C2\u00A0 16\u00C2\u00A0 69\u00C2\u00A0 0.24\u00C2\u00A0 .013\u00C2\u00A0 2.1\u00C2\u00A0 0.8\u00C2\u00A0 84.4\u00C2\u00A0 1.8\u00C2\u00A0 .0291\u00C2\u00A0 47.4\u00C2\u00A0 0.05\u00C2\u00A0 47.5\u00C2\u00A0 .0129\u00C2\u00A0 2.6\u00C2\u00A0 .056\u00C2\u00A0 6\u00C2\u00A0 0.000946\u00C2\u00A0 72\u00C2\u00A0 .048\u00C2\u00A0 6.7\u00C2\u00A0 .076\u00C2\u00A0 7.0\u00C2\u00A0 25\u00C2\u00A0 113\u00C2\u00A0 0.23\u00C2\u00A0 .014\u00C2\u00A0 1.7\u00C2\u00A0 1.4\u00C2\u00A0 91.8\u00C2\u00A0 1.6\u00C2\u00A0 .0336\u00C2\u00A0 32.4\u00C2\u00A0 0.07\u00C2\u00A0 32.4\u00C2\u00A0 .0141\u00C2\u00A0 2.1\u00C2\u00A0 .064\u00C2\u00A0 7\u00C2\u00A0 0.000000\u00C2\u00A0 0\u00C2\u00A0 .057\u00C2\u00A0 7.3\u00C2\u00A0 .073\u00C2\u00A0 8.9\u00C2\u00A0 16\u00C2\u00A0 80\u00C2\u00A0 0.20\u00C2\u00A0 .014\u00C2\u00A0 2.0\u00C2\u00A0 0.9\u00C2\u00A0 85.9\u00C2\u00A0 1.8\u00C2\u00A0 .0572\u00C2\u00A0 7.3\u00C2\u00A0 0.11\u00C2\u00A0 7.6\u00C2\u00A0 .0136\u00C2\u00A0 2.0\u00C2\u00A0 .265\u00C2\u00A0 8\u00C2\u00A0 0.001973\u00C2\u00A0 26\u00C2\u00A0 .049\u00C2\u00A0 8.0\u00C2\u00A0 .093\u00C2\u00A0 7.8\u00C2\u00A0 18\u00C2\u00A0 72\u00C2\u00A0 0.26\u00C2\u00A0 .014\u00C2\u00A0 2.1\u00C2\u00A0 0.9\u00C2\u00A0 91.2\u00C2\u00A0 1.9\u00C2\u00A0 .0188\u00C2\u00A0 48.8\u00C2\u00A0 0.04\u00C2\u00A0 48.9\u00C2\u00A0 .0138\u00C2\u00A0 2.3\u00C2\u00A0 .047\u00C2\u00A0 9\u00C2\u00A0 0.000717\u00C2\u00A0 41\u00C2\u00A0 .050\u00C2\u00A0 4.0\u00C2\u00A0 .214\u00C2\u00A0 5.8\u00C2\u00A0 173\u00C2\u00A0 279\u00C2\u00A0 0.64\u00C2\u00A0 .014\u00C2\u00A0 1.0\u00C2\u00A0 3.4\u00C2\u00A0 89.4\u00C2\u00A0 0.9\u00C2\u00A0 .0390\u00C2\u00A0 12.6\u00C2\u00A0 0.07\u00C2\u00A0 12.6\u00C2\u00A0 .0138\u00C2\u00A0 1.2\u00C2\u00A0 .093\u00C2\u00A0 10\u00C2\u00A0 \u00E2\u0080\u00900.000381\u00C2\u00A0 50\u00C2\u00A0 .051\u00C2\u00A0 5.0\u00C2\u00A0 .093\u00C2\u00A0 5.0\u00C2\u00A0 51\u00C2\u00A0 187\u00C2\u00A0 0.28\u00C2\u00A0 .014\u00C2\u00A0 1.3\u00C2\u00A0 2.2\u00C2\u00A0 87.4\u00C2\u00A0 1.2\u00C2\u00A0 .0570\u00C2\u00A0 6.6\u00C2\u00A0 0.11\u00C2\u00A0 6.8\u00C2\u00A0 .0138\u00C2\u00A0 1.3\u00C2\u00A0 .199\u00C2\u00A0 11\u00C2\u00A0 0.001837\u00C2\u00A0 41\u00C2\u00A0 .047\u00C2\u00A0 5.2\u00C2\u00A0 .083\u00C2\u00A0 5.7\u00C2\u00A0 37\u00C2\u00A0 172\u00C2\u00A0 0.22\u00C2\u00A0 .013\u00C2\u00A0 1.3\u00C2\u00A0 2.0\u00C2\u00A0 86.3\u00C2\u00A0 1.2\u00C2\u00A0 .0190\u00C2\u00A0 64.4\u00C2\u00A0 0.03\u00C2\u00A0 64.5\u00C2\u00A0 .0130\u00C2\u00A0 1.9\u00C2\u00A0 .030\u00C2\u00A0 \u00C2\u00A0 0000\u00C2\u00A0 0\u00C2\u00A0 .053 8.4\u00C2\u00A0 .124\u00C2\u00A0 7.8\u00C2\u00A0 19\u00C2\u00A0 62\u00C2\u00A0 0.31\u00C2\u00A0 .012 4.5\u00C2\u00A0 66\u00C2\u00A0 114\u00C2\u00A0 0.60\u00C2\u00A0 .0 6.8\u00C2\u00A0 \u00C2\u00A0 0.7 79.1\u00C2\u00A0 2.2\u00C2\u00A0 .0528\u00C2\u00A0 8.4\u00C2\u00A0 0.0 79.8\u00C2\u00A0 1.4\u00C2\u00A0 .0 1547\u00C2\u00A0 1\u00C2\u00A0 .052 7.7\u00C2\u00A0 .216\u00C2\u00A0 5.2\u00C2\u00A0 46\u00C2\u00A0 83\u00C2\u00A0 0.57\u00C2\u00A0 2.9\u00C2\u00A0 241\u00C2\u00A0 604\u00C2\u00A0 0.41\u00C2\u00A0 5.9\u00C2\u00A0 \u00C2\u00A0 0.9 78.5\u00C2\u00A0 1.6\u00C2\u00A0 .028 0.000359\u00C2\u00A0 41\u00C2\u00A0 .050 4.7\u00C2\u00A0 .123 4.1\u00C2\u00A0 5.3\u00C2\u00A0 84\u00C2\u00A0 238\u00C2\u00A0 0.36\u00C2\u00A0 .01 4.2\u00C2\u00A0 69\u00C2\u00A0 315\u00C2\u00A0 0.23\u00C2\u00A0 .013 \u00C2\u00A0 2.6 80.7\u00C2\u00A0 1.0\u00C2\u00A0 .0448 0. 1194\u00C2\u00A0 2\u00C2\u00A0 .047 7.0\u00C2\u00A0 4.4\u00C2\u00A0 .094\u00C2\u00A0 9.0\u00C2\u00A0 30\u00C2\u00A0 112\u00C2\u00A0 0.27\u00C2\u00A0 .0 4.3\u00C2\u00A0 70\u00C2\u00A0 \u00C2\u00A0 1.2 80.7\u00C2\u00A0 1.4\u00C2\u00A0 .02 Appendix\u00C2\u00A0A\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A0219\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0A4\u00C2\u00A0continued.\u00C2\u00A0 \u00C2\u00A0 206 206 206 238 238 206 235 Corr\u00C2\u00A0 206Pb / U\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 Rad\u00C2\u00A0 206Pb\u00C2\u00A0 (ppm)\u00C2\u00A0 207\u00C2\u00A0 corr\u00C2\u00A0 206Pb\u00C2\u00A0 /238U\u00C2\u00A0 Age\u00C2\u00A0 1\u00CF\u0083\u00C2\u00A0 err\u00C2\u00A0 204\u00C2\u00A0 corr\u00C2\u00A0 207Pb\u00C2\u00A0 / Pb\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 204\u00C2\u00A0 corr\u00C2\u00A0 207Pb\u00C2\u00A0 / U\u00C2\u00A0 204\u00C2\u00A0 corr\u00C2\u00A0 206Pb /238U\u00C2\u00A0 Meas\u00C2\u00A0 204Pb/\u00C2\u00A0 Pb\u00C2\u00A0 Meas\u00C2\u00A0 207Pb/\u00C2\u00A0 Pb\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 Meas\u00C2\u00A0 208Pb/\u00C2\u00A0 Pb\u00C2\u00A0 232Th / U\u00C2\u00A0 Spot\u00C2\u00A0 Name\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 Th\u00C2\u00A0 ppm\u00C2\u00A0 U\u00C2\u00A0 ppm\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 err\u00C2\u00A0 corr\u00C2\u00A0 LW\u00E2\u0080\u009030\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0Biotite\u00C2\u00A0+/\u00E2\u0080\u0090hornblende\u00E2\u0080\u0090bearing\u00C2\u00A0coarse\u00C2\u00A0grained\u00C2\u00A0meta\u00E2\u0080\u0090granodiorite\u00C2\u00A0w/\u00C2\u00A0some\u00C2\u00A0xenoliths\u00C2\u00A0 1\u00C2\u00A0 0.000151\u00C2\u00A0 32\u00C2\u00A0 .054\u00C2\u00A0 1.2\u00C2\u00A0 .024\u00C2\u00A0 2.9\u00C2\u00A0 81\u00C2\u00A0 1 4 2 1 8 23 4 2 1 7 2 1 5 2 2 6 20 1 5 2 1 1 2 4 2 1 2 0.25\u00C2\u00A0 .128\u00C2\u00A0 0.4\u00C2\u00A0 73.4\u00C2\u00A0 771.3\u00C2\u00A0 3.7\u00C2\u00A0 .0685\u00C2\u00A0 2.3\u00C2\u00A0 1.21\u00C2\u00A0 2.4\u00C2\u00A0 .1277\u00C2\u00A0 0.4\u00C2\u00A0 .189\u00C2\u00A0 3\u00C2\u00A0 1 2 2 4 .0593\u00C2\u00A0 1.6\u00C2\u00A0 0.65\u00C2\u00A0 1.7\u00C2\u00A0 4\u00C2\u00A0 1 10 5\u00C2\u00A0 3 1 3 5 6\u00C2\u00A0 2 1 5 7\u00C2\u00A0 1 1 4 8\u00C2\u00A0 1 10 1 9\u00C2\u00A0 1 2 5 4 520\u00C2\u00A0 41\u00C2\u00A0 0.06\u00C2\u00A0 .037\u00C2\u00A0 0.4\u00C2\u00A0 5.7\u00C2\u00A0 32.8\u00C2\u00A0 0.9\u00C2\u00A0 .0515\u00C2\u00A0 1.9\u00C2\u00A0 0.26\u00C2\u00A0 2.0\u00C2\u00A0 .0368\u00C2\u00A0 0.4\u00C2\u00A0 .189\u00C2\u00A0 2\u00C2\u00A0 0.000184\u00C2\u00A0 51\u00C2\u00A0 .069\u00C2\u00A0 2.5\u00C2\u00A0 .221\u00C2\u00A0 2.2\u00C2\u00A0 45\u00C2\u00A0 0.68\u00C2\u00A0 .134\u00C2\u00A0 1.2\u00C2\u00A0 7.9\u00C2\u00A0 09.3\u00C2\u00A0 9.5\u00C2\u00A0 .0667\u00C2\u00A0 3.4\u00C2\u00A0 1.23\u00C2\u00A0 3.6\u00C2\u00A0 .1339\u00C2\u00A0 1.2\u00C2\u00A0 .338\u00C2\u00A0 3\u00C2\u00A0 0.000024\u00C2\u00A0 41\u00C2\u00A0 .050\u00C2\u00A0 1.2\u00C2\u00A0 .018\u00C2\u00A0 3.0\u00C2\u00A0 78\u00C2\u00A0 32\u00C2\u00A0 0.05\u00C2\u00A0 0.4\u00C2\u00A0 8.6\u00C2\u00A0 35.5\u00C2\u00A0 1.0\u00C2\u00A0 .0499\u00C2\u00A0 1.3\u00C2\u00A0 0.26\u00C2\u00A0 1.3\u00C2\u00A0 .0372\u00C2\u00A0 0.4\u00C2\u00A0 .313\u00C2\u00A0.037\u00C2\u00A0 4\u00C2\u00A0 0.000068\u00C2\u00A0 22\u00C2\u00A0 .051\u00C2\u00A0 1.1\u00C2\u00A0 .018\u00C2\u00A0 2.7\u00C2\u00A0 177\u00C2\u00A0 8 737\u00C2\u00A0 66\u00C2\u00A0 0.08\u00C2\u00A0 .036\u00C2\u00A0 0.3\u00C2\u00A0 1.8\u00C2\u00A0 27.1\u00C2\u00A0 0.8\u00C2\u00A0 .0497\u00C2\u00A0 1.2\u00C2\u00A0 0.25\u00C2\u00A0 1.3\u00C2\u00A0 .0358\u00C2\u00A0 0.3\u00C2\u00A0 .258\u00C2\u00A0 5\u00C2\u00A0 0.000217\u00C2\u00A0 22\u00C2\u00A0 .051\u00C2\u00A0 1.0\u00C2\u00A0 .007\u00C2\u00A0 4.2\u00C2\u00A0 54\u00C2\u00A0 0.03\u00C2\u00A0 .036\u00C2\u00A0 0.3\u00C2\u00A0 8.1\u00C2\u00A0 29.3\u00C2\u00A0 0.7\u00C2\u00A0 .0479\u00C2\u00A0 2.1\u00C2\u00A0 0.24\u00C2\u00A0 2.1\u00C2\u00A0 .0361\u00C2\u00A0 0.3\u00C2\u00A0 .147\u00C2\u00A0 6\u00C2\u00A0 0.000034\u00C2\u00A0 39\u00C2\u00A0 .062\u00C2\u00A0 1.3\u00C2\u00A0 .024\u00C2\u00A0 3.2\u00C2\u00A0 26\u00C2\u00A0 587\u00C2\u00A0 0.08\u00C2\u00A0 .103\u00C2\u00A0 0.6\u00C2\u00A0 8.8\u00C2\u00A0 28.8\u00C2\u00A0 3.5\u00C2\u00A0 .0614\u00C2\u00A0 1.4\u00C2\u00A0 0.87\u00C2\u00A0 1.5\u00C2\u00A0 .1026\u00C2\u00A0 0.6\u00C2\u00A0 .374\u00C2\u00A0 7\u00C2\u00A0 0.000001\u00C2\u00A0 78\u00C2\u00A0 .052\u00C2\u00A0 1.1\u00C2\u00A0 .015\u00C2\u00A0 3.0\u00C2\u00A0 80\u00C2\u00A0 324\u00C2\u00A0 0.05\u00C2\u00A0 .036\u00C2\u00A0 0.3\u00C2\u00A0 3.5\u00C2\u00A0 26.7\u00C2\u00A0 0.7\u00C2\u00A0 .0516\u00C2\u00A0 1.2\u00C2\u00A0 0.25\u00C2\u00A0 1.2\u00C2\u00A0 .0358\u00C2\u00A0 0.3\u00C2\u00A0 .262\u00C2\u00A0 8\u00C2\u00A0 0.000152\u00C2\u00A0 21\u00C2\u00A0 .051\u00C2\u00A0 1.9\u00C2\u00A0 .058\u00C2\u00A0 2.7\u00C2\u00A0 03\u00C2\u00A0 528\u00C2\u00A0 0.18\u00C2\u00A0 .036\u00C2\u00A0 0.6\u00C2\u00A0 8.2\u00C2\u00A0 28.3\u00C2\u00A0 1.3\u00C2\u00A0 .0490\u00C2\u00A0 2.3\u00C2\u00A0 0.24\u00C2\u00A0 2.4\u00C2\u00A0 .0360\u00C2\u00A0 0.6\u00C2\u00A0 .242\u00C2\u00A0 9\u00C2\u00A0 0.000090\u00C2\u00A0 38\u00C2\u00A0 .051\u00C2\u00A0 1.3\u00C2\u00A0 .019\u00C2\u00A0 3.1\u00C2\u00A0 88\u00C2\u00A0 366\u00C2\u00A0 0.07\u00C2\u00A0 .037\u00C2\u00A0 0.4\u00C2\u00A0 2.3\u00C2\u00A0 35.4\u00C2\u00A0 0.9\u00C2\u00A0 .0493\u00C2\u00A0 1.7\u00C2\u00A0 0.25\u00C2\u00A0 1.7\u00C2\u00A0 .0371\u00C2\u00A0 0.4\u00C2\u00A0 .225\u00C2\u00A0 20\u00C2\u00A0 0.000085\u00C2\u00A0 14\u00C2\u00A0 .051\u00C2\u00A0 1.9\u00C2\u00A0 .020\u00C2\u00A0 4.6\u00C2\u00A0 32\u00C2\u00A0 .279\u00C2\u00A0305\u00C2\u00A0 0.06\u00C2\u00A0 .036\u00C2\u00A0 0.6\u00C2\u00A0 6.4\u00C2\u00A0 28.8\u00C2\u00A0 1.3\u00C2\u00A0 .0496\u00C2\u00A0 2.0\u00C2\u00A0 0.25\u00C2\u00A0 2.1\u00C2\u00A0 .0361\u00C2\u00A0 0.6\u00C2\u00A0 21\u00C2\u00A0 0.000107\u00C2\u00A0 42\u00C2\u00A0 .054\u00C2\u00A0 1.5\u00C2\u00A0 .056\u00C2\u00A0 2.7\u00C2\u00A0 50\u00C2\u00A0 210\u00C2\u00A0 0.14\u00C2\u00A0 .055\u00C2\u00A0 0.7\u00C2\u00A0 17.4\u00C2\u00A0 347.1\u00C2\u00A0 2.4\u00C2\u00A0 .0528\u00C2\u00A0 2.0\u00C2\u00A0 0.40\u00C2\u00A0 2.2\u00C2\u00A0 .0553\u00C2\u00A0 0.7\u00C2\u00A0 .329\u00C2\u00A0 22\u00C2\u00A0 0.000029\u00C2\u00A0 34\u00C2\u00A0 .069\u00C2\u00A0 2.3\u00C2\u00A0 .085\u00C2\u00A0 2.9\u00C2\u00A0 161\u00C2\u00A0 88\u00C2\u00A0 2 0.000096\u00C2\u00A0 22\u00C2\u00A0 .061\u00C2\u00A0 1.4\u00C2\u00A0 .165\u00C2\u00A0 1.6\u00C2\u00A0 22\u00C2\u00A0 12\u00C2\u00A0 0.41\u00C2\u00A0 .080\u00C2\u00A0 0.6\u00C2\u00A0 .372\u00C2\u00A0 .417\u00C2\u00A0 1.0\u00C2\u00A0 94.0\u00C2\u00A0 3.1\u00C2\u00A0 .0799\u00C2\u00A0 0.6\u00C2\u00A0 2 \u00E2\u0080\u00900.000135\u00C2\u00A0 56\u00C2\u00A0 .077\u00C2\u00A0 1.5\u00C2\u00A0 .269\u00C2\u00A0 1.6\u00C2\u00A0 83\u00C2\u00A0 340\u00C2\u00A0 0.87\u00C2\u00A0 .181\u00C2\u00A0 0.9\u00C2\u00A0 5.5\u00C2\u00A0 69.9\u00C2\u00A0 9.7\u00C2\u00A0 .0791\u00C2\u00A0 2.0\u00C2\u00A0 1.98\u00C2\u00A0 2.2\u00C2\u00A0 .1815\u00C2\u00A0 0.9\u00C2\u00A0 .339\u00C2\u00A02 0.000159\u00C2\u00A0 9\u00C2\u00A0 .059\u00C2\u00A0 2.6\u00C2\u00A0 .342\u00C2\u00A0 1.2\u00C2\u00A0 51\u00C2\u00A0 326\u00C2\u00A0 4.13\u00C2\u00A0 .091\u00C2\u00A0 1.1\u00C2\u00A0 6.9\u00C2\u00A0 60.8\u00C2\u00A0 6.3\u00C2\u00A0 .0568\u00C2\u00A0 3.2\u00C2\u00A0 0.71\u00C2\u00A0 3.4\u00C2\u00A0 .0907\u00C2\u00A0 1.1\u00C2\u00A0 .343\u00C2\u00A02 0.000038\u00C2\u00A0 67\u00C2\u00A0 .058\u00C2\u00A0 1.9\u00C2\u00A0 .444\u00C2\u00A0 1.1\u00C2\u00A0 86\u00C2\u00A0 668\u00C2\u00A0 1.39\u00C2\u00A0 .097\u00C2\u00A0 0.7\u00C2\u00A0 7.6\u00C2\u00A0 96.1\u00C2\u00A0 4.3\u00C2\u00A0 .0572\u00C2\u00A0 2.0\u00C2\u00A0 0.76\u00C2\u00A0 2.1\u00C2\u00A0 .0966\u00C2\u00A0 0.7\u00C2\u00A0 .368\u00C2\u00A02 \u00E2\u0080\u00900.000058\u00C2\u00A0 59\u00C2\u00A0 .057\u00C2\u00A0 1.8\u00C2\u00A0 .218\u00C2\u00A0 1.7\u00C2\u00A0 38\u00C2\u00A0 69\u00C2\u00A0 0.68\u00C2\u00A0 .080\u00C2\u00A0 0.8\u00C2\u00A0 4.4\u00C2\u00A0 96.2\u00C2\u00A0 3.9\u00C2\u00A0 .0581\u00C2\u00A0 2.0\u00C2\u00A0 0.64\u00C2\u00A0 2.1\u00C2\u00A0 .0801\u00C2\u00A0 0.8\u00C2\u00A0 .524\u00C2\u00A02 0.000082\u00C2\u00A0 52\u00C2\u00A0 .080\u00C2\u00A0 1.3\u00C2\u00A0 .135\u00C2\u00A0 1.8\u00C2\u00A0 45\u00C2\u00A0 120\u00C2\u00A0 0.39\u00C2\u00A0 .178\u00C2\u00A0 1.0\u00C2\u00A0 8.4\u00C2\u00A0 50.5\u00C2\u00A0 0.0\u00C2\u00A0 .0790\u00C2\u00A0 1.6\u00C2\u00A0 1.94\u00C2\u00A0 1.9\u00C2\u00A0 .1780\u00C2\u00A0 1.0\u00C2\u00A0 2 0.000051\u00C2\u00A0 44\u00C2\u00A0 .063\u00C2\u00A0 2.6\u00C2\u00A0 .128\u00C2\u00A0 3.8\u00C2\u00A0 33\u00C2\u00A0 99\u00C2\u00A0 0.40\u00C2\u00A0 .098\u00C2\u00A0 0.6\u00C2\u00A0 8.5\u00C2\u00A0 97.8\u00C2\u00A0 3.9\u00C2\u00A0 .0622\u00C2\u00A0 2.7\u00C2\u00A0 0.84\u00C2\u00A0 2.7\u00C2\u00A0 .0975\u00C2\u00A0 0.6\u00C2\u00A0 .234\u00C2\u00A0 Appendix\u00C2\u00A0A\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A0220\u00C2\u00A0 \u00C2\u00A0Appendix\u00C2\u00A0A\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A0221\u00C2\u00A0 Spot\u00C2\u00A0 \u00C2\u00A0 Meas\u00C2\u00A0 2 %\u00C2\u00A0 Meas\u00C2\u00A0 %\u00C2\u00A0 Meas\u00C2\u00A0 %\u00C2\u00A0 Th\u00C2\u00A0 U\u00C2\u00A0 \u00C2\u00A0 232Th Corr\u00C2\u00A0 %\u00C2\u00A0 Rad\u00C2\u00A0 207\u00C2\u00A0 1\u00CF\u0083\u00C2\u00A0 204\u00C2\u00A0 %\u00C2\u00A0 204\u00C2\u00A0 %\u00C2\u00A0 204\u00C2\u00A0 %\u00C2\u00A0 err\u00C2\u00A0 Table\u00C2\u00A0A4\u00C2\u00A0continued.\u00C2\u00A0 Name 04Pb/\u00C2\u00A0 206Pb\u00C2\u00A0 err\u00C2\u00A0 207Pb/\u00C2\u00A0 206Pb\u00C2\u00A0 err\u00C2\u00A0 208Pb/\u00C2\u00A0 206Pb\u00C2\u00A0 err\u00C2\u00A0 ppm\u00C2\u00A0 ppm /238U\u00C2\u00A0 206Pb /238U\u00C2\u00A0 err\u00C2\u00A0 206Pb\u00C2\u00A0 (ppm)\u00C2\u00A0 corr\u00C2\u00A0 206Pb\u00C2\u00A0 /238U\u00C2\u00A0 Age\u00C2\u00A0 err\u00C2\u00A0 corr\u00C2\u00A0 207Pb\u00C2\u00A0 /206Pb\u00C2\u00A0 err\u00C2\u00A0 corr\u00C2\u00A0 207Pb\u00C2\u00A0 /235U\u00C2\u00A0 err\u00C2\u00A0 corr\u00C2\u00A0 206Pb /238U\u00C2\u00A0 err\u00C2\u00A0 corr\u00C2\u00A0 LW\u00E2\u0080\u009031\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0 ite\u00E2\u0080\u0090 \u00E2\u0080\u0090be me rai anMuscov biotite aring\u00C2\u00A0 d\u00E2\u0080\u0090g ned\u00C2\u00A0gr ite\u00C2\u00A0 1\u00C2\u00A0 0.008481\u00C2\u00A0 6\u00C2\u00A0 .174\u00C2\u00A0 2.0\u00C2\u00A0 .326\u00C2\u00A0 2.7\u00C2\u00A0 239\u00C2\u00A0 1632\u00C2\u00A0 0.03\u00C2\u00A0 .016\u00C2\u00A0 0.3\u00C2\u00A0 110.7\u00C2\u00A0 86.8\u00C2\u00A0 2.0\u00C2\u00A0 .0489\u00C2\u00A0 44.7\u00C2\u00A0 0.09\u00C2\u00A0 44.7\u00C2\u00A0 .0136\u00C2\u00A0 1.4\u00C2\u00A0 .032\u00C2\u00A0 1 1 11 3 \u00C2\u00A0 \u00C2\u00A0 1 \u00C2\u00A0 3 \u00C2\u00A0 \u00C2\u00A0 1 1 1 1 2 1 1 3 1 24\u00C2\u00A0 0.000076\u00C2\u00A0 36\u00C2\u00A0 .073\u00C2\u00A0 1.2\u00C2\u00A0 .254\u00C2\u00A0 1.2\u00C2\u00A0 133\u00C2\u00A0 168\u00C2\u00A0 0.82\u00C2\u00A0 .164\u00C2\u00A0 0.7\u00C2\u00A0 23.7\u00C2\u00A0 980.6\u00C2\u00A0 7.1\u00C2\u00A0 .0716\u00C2\u00A0 1.4\u00C2\u00A0 1.62\u00C2\u00A0 1.6\u00C2\u00A0 .1642\u00C2\u00A0 0.7\u00C2\u00A0 .467\u00C2\u00A0 25\u00C2\u00A0 0.000000\u00C2\u00A0 0\u00C2\u00A0 .177\u00C2\u00A0 1.4\u00C2\u00A0 .139\u00C2\u00A0 2.1\u00C2\u00A0 137\u00C2\u00A0 970\u00C2\u00A0 0.49\u00C2\u00A0 .428\u00C2\u00A0 1.4\u00C2\u00A0 107.1\u00C2\u00A0 2190.5\u00C2\u00A0 37.8\u00C2\u00A0 .1774\u00C2\u00A0 1.4\u00C2\u00A0 10.48\u00C2\u00A0 2.0\u00C2\u00A0 .4285\u00C2\u00A0 1.4\u00C2\u00A0 .695\u00C2\u00A0 26\u00C2\u00A0 0.000035\u00C2\u00A0 45\u00C2\u00A0 .073\u00C2\u00A0 1.1\u00C2\u00A0 .032\u00C2\u00A0 7.5\u00C2\u00A0 29\u00C2\u00A0 3366\u00C2\u00A0 0.11\u00C2\u00A0 .148\u00C2\u00A0 0.6\u00C2\u00A0 36.7\u00C2\u00A0 883.6\u00C2\u00A0 5.5\u00C2\u00A0 .0727\u00C2\u00A0 1.1\u00C2\u00A0 1.48\u00C2\u00A0 1.3\u00C2\u00A0 .1477\u00C2\u00A0 0.6\u00C2\u00A0 .481\u00C2\u00A0 27\u00C2\u00A0 \u00E2\u0080\u00900.000139\u00C2\u00A0 55\u00C2\u00A0 .096\u00C2\u00A0 1.2\u00C2\u00A0 .205\u00C2\u00A0 1.5\u00C2\u00A0 55\u00C2\u00A0 86\u00C2\u00A0 0.67\u00C2\u00A0 .263\u00C2\u00A0 0.9\u00C2\u00A0 19.4\u00C2\u00A0 1500.9\u00C2\u00A0 14.1\u00C2\u00A0 .0976\u00C2\u00A0 1.6\u00C2\u00A0 3.55\u00C2\u00A0 1.9\u00C2\u00A0 .2635\u00C2\u00A0 1.0\u00C2\u00A0 .505\u00C2\u00A0 28\u00C2\u00A0 0.000000\u00C2\u00A0 0\u00C2\u00A0 .060\u00C2\u00A0 1.4\u00C2\u00A0 .100\u00C2\u00A0 4.6\u00C2\u00A0 189\u00C2\u00A0 254\u00C2\u00A0 0.29\u00C2\u00A0 .110\u00C2\u00A0 0.5\u00C2\u00A0 63.1\u00C2\u00A0 675.7\u00C2\u00A0 3.1\u00C2\u00A0 .0603\u00C2\u00A0 1.4\u00C2\u00A0 0.92\u00C2\u00A0 1.5\u00C2\u00A0 .1103\u00C2\u00A0 0.5\u00C2\u00A0 .305\u00C2\u00A0 29\u00C2\u00A0 0.000037\u00C2\u00A0 67\u00C2\u00A0 .058\u00C2\u00A0 1.6\u00C2\u00A0 .626\u00C2\u00A0 1.0\u00C2\u00A0 451\u00C2\u00A0 237\u00C2\u00A0 1.97\u00C2\u00A0 .085\u00C2\u00A0 0.7\u00C2\u00A0 17.3\u00C2\u00A0 527.1\u00C2\u00A0 3.7\u00C2\u00A0 .0576\u00C2\u00A0 1.8\u00C2\u00A0 0.68\u00C2\u00A0 1.9\u00C2\u00A0 .0852\u00C2\u00A0 0.7\u00C2\u00A0 .380\u00C2\u00A0 30\u00C2\u00A0 \u00E2\u0080\u00900.000164\u00C2\u00A0 1\u00C2\u00A0 .052\u00C2\u00A0 2.5\u00C2\u00A0 .207\u00C2\u00A0 2.3\u00C2\u00A0 144\u00C2\u00A0 47\u00C2\u00A0 0.66\u00C2\u00A0 .042\u00C2\u00A0 0.9\u00C2\u00A0 8.1\u00C2\u00A0 263.6\u00C2\u00A0 2.4\u00C2\u00A0 .0548\u00C2\u00A0 2.4\u00C2\u00A0 0.32\u00C2\u00A0 2.6\u00C2\u00A0 .0419\u00C2\u00A0 0.9\u00C2\u00A0 .349\u00C2\u00A0 31\u00C2\u00A0 0.000032\u00C2\u00A0 16\u00C2\u00A0 .163\u00C2\u00A0 1.5\u00C2\u00A0 .102\u00C2\u00A0 1.0\u00C2\u00A0 65\u00C2\u00A0 291\u00C2\u00A0 0.36\u00C2\u00A0 .454\u00C2\u00A0 1.2\u00C2\u00A0 72.5\u00C2\u00A0 2381.7\u00C2\u00A0 33.6\u00C2\u00A0 .1631\u00C2\u00A0 1.5\u00C2\u00A0 10.19\u00C2\u00A0 1.9\u00C2\u00A0 .4533\u00C2\u00A0 1.2\u00C2\u00A0 .616\u00C2\u00A0 32\u00C2\u00A0 0.000041\u00C2\u00A0 5\u00C2\u00A0 .064\u00C2\u00A0 1.0\u00C2\u00A0 .121\u00C2\u00A0 1.3\u00C2\u00A0 148\u00C2\u00A0 186\u00C2\u00A0 0.35\u00C2\u00A0 .119\u00C2\u00A0 0.5\u00C2\u00A0 44.1\u00C2\u00A0 723.7\u00C2\u00A0 3.5\u00C2\u00A0 .0629\u00C2\u00A0 1.0\u00C2\u00A0 1.03\u00C2\u00A0 1.2\u00C2\u00A0 .1187\u00C2\u00A0 0.5\u00C2\u00A0 .426\u00C2\u00A0 2\u00C2\u00A0 0.008222\u00C2\u00A0 5\u00C2\u00A0 .160\u00C2\u00A0 0.7\u00C2\u00A0 .291\u00C2\u00A0 1.5\u00C2\u00A0 64\u00C2\u00A0 8038\u00C2\u00A0 0.04\u00C2\u00A0 .029\u00C2\u00A0 0.4\u00C2\u00A0 92.7\u00C2\u00A0 157.4\u00C2\u00A0 3.1\u00C2\u00A0 .0371\u00C2\u00A0 55.7\u00C2\u00A0 0.12\u00C2\u00A0 55.7\u00C2\u00A0 .0244\u00C2\u00A0 1.4\u00C2\u00A0 .025\u00C2\u00A0 3\u00C2\u00A0 0.002552\u00C2\u00A0 10\u00C2\u00A0 .086\u00C2\u00A0 1.4\u00C2\u00A0 .096\u00C2\u00A0 3.7\u00C2\u00A0 54\u00C2\u00A0 5149\u00C2\u00A0 0.03\u00C2\u00A0 .025\u00C2\u00A0 0.4\u00C2\u00A0 2.8\u00C2\u00A0 155.0\u00C2\u00A0 1.1\u00C2\u00A0 .0484\u00C2\u00A0 14.0\u00C2\u00A0 0.16\u00C2\u00A0 14.1\u00C2\u00A0 .0243\u00C2\u00A0 0.7\u00C2\u00A0 .049\u00C2\u00A0 4\u00C2\u00A0 0.002809\u00C2\u00A0 5\u00C2\u00A0 .093\u00C2\u00A0 1.1\u00C2\u00A0 .116\u00C2\u00A0 2.2\u00C2\u00A0 56\u00C2\u00A0 3772\u00C2\u00A0 0.10\u00C2\u00A0 .027\u00C2\u00A0 0.2\u00C2\u00A0 89.5\u00C2\u00A0 162.7\u00C2\u00A0 1.2\u00C2\u00A0 .0522\u00C2\u00A0 12.0\u00C2\u00A0 0.18\u00C2\u00A0 12.0\u00C2\u00A0 .0256\u00C2\u00A0 0.4\u00C2\u00A0 .037\u00C2\u00A0 5\u00C2\u00A0 0.000164\u00C2\u00A0 38\u00C2\u00A0 .051\u00C2\u00A0 1.3\u00C2\u00A0 .003\u00C2\u00A0 7.3\u00C2\u00A0 18\u00C2\u00A0 3856\u00C2\u00A0 0.01\u00C2\u00A0 .036\u00C2\u00A0 0.4\u00C2\u00A0 60.5\u00C2\u00A0 227.2\u00C2\u00A0 0.9\u00C2\u00A0 .0487\u00C2\u00A0 2.4\u00C2\u00A0 0.24\u00C2\u00A0 2.4\u00C2\u00A0 .0358\u00C2\u00A0 0.4\u00C2\u00A0 .162\u00C2\u00A0 6 \u00E2\u0080\u00900.000243\u00C2\u00A0 1\u00C2\u00A0 .053\u00C2\u00A0 2.9\u00C2\u00A0 .215\u00C2\u00A0 2.2\u00C2\u00A0 83\u00C2\u00A0 117\u00C2\u00A0 0.68\u00C2\u00A0 .067\u00C2\u00A0 1.0\u00C2\u00A0 7.3\u00C2\u00A0 419.5\u00C2\u00A0 4.0\u00C2\u00A0 .0566\u00C2\u00A0 2.9\u00C2\u00A0 0.53\u00C2\u00A0 3.0\u00C2\u00A0 .0673\u00C2\u00A0 1.0\u00C2\u00A0 .320\u00C2\u00A0 10 0.000949\u00C2\u00A0 20\u00C2\u00A0 .052\u00C2\u00A0 3.7\u00C2\u00A0 .054\u00C2\u00A0 6.4\u00C2\u00A0 19\u00C2\u00A0 964\u00C2\u00A0 0.16\u00C2\u00A0 .036\u00C2\u00A0 1.3\u00C2\u00A0 3.6\u00C2\u00A0 228.7\u00C2\u00A0 3.0\u00C2\u00A0 .0375\u00C2\u00A0 10.4\u00C2\u00A0 0.18\u00C2\u00A0 10.5\u00C2\u00A0 .0355\u00C2\u00A0 1.4\u00C2\u00A0 .129\u00C2\u00A0 11 \u00E2\u0080\u00900.000015\u00C2\u00A0 0\u00C2\u00A0 .072\u00C2\u00A0 0.5\u00C2\u00A0 .111\u00C2\u00A0 1.3\u00C2\u00A0 41\u00C2\u00A0 399\u00C2\u00A0 0.36\u00C2\u00A0 .166\u00C2\u00A0 0.4\u00C2\u00A0 137.9\u00C2\u00A0 987.5\u00C2\u00A0 3.4\u00C2\u00A0 .0721\u00C2\u00A0 0.5\u00C2\u00A0 1.65\u00C2\u00A0 0.6\u00C2\u00A0 .1656\u00C2\u00A0 0.4\u00C2\u00A0 .565\u00C2\u00A0 12 0.000044\u00C2\u00A0 35\u00C2\u00A0 .075\u00C2\u00A0 0.5\u00C2\u00A0 .131\u00C2\u00A0 0.9\u00C2\u00A0 336\u00C2\u00A0 227\u00C2\u00A0 0.37\u00C2\u00A0 .164\u00C2\u00A0 0.4\u00C2\u00A0 132.6\u00C2\u00A0 972.9\u00C2\u00A0 3.5\u00C2\u00A0 .0747\u00C2\u00A0 0.6\u00C2\u00A0 1.68\u00C2\u00A0 0.7\u00C2\u00A0 .1636\u00C2\u00A0 0.4\u00C2\u00A0 .506\u00C2\u00A0 13 0.000162\u00C2\u00A0 48\u00C2\u00A0 .050\u00C2\u00A0 2.0\u00C2\u00A0 .065\u00C2\u00A0 3.2\u00C2\u00A0 79\u00C2\u00A0 471\u00C2\u00A0 0.21\u00C2\u00A0 .036\u00C2\u00A0 0.7\u00C2\u00A0 12.4\u00C2\u00A0 228.7\u00C2\u00A0 1.7\u00C2\u00A0 .0476\u00C2\u00A0 3.3\u00C2\u00A0 0.24\u00C2\u00A0 3.4\u00C2\u00A0 .0360\u00C2\u00A0 0.7\u00C2\u00A0 .219\u00C2\u00A0 14\u00C2\u00A0 0.000032\u00C2\u00A0 40\u00C2\u00A0 .114\u00C2\u00A0 0.7\u00C2\u00A0 .124\u00C2\u00A0 2.4\u00C2\u00A0 00\u00C2\u00A0 052\u00C2\u00A0 0.44\u00C2\u00A0 .323\u00C2\u00A0 0.6\u00C2\u00A0 65.6\u00C2\u00A0 794.4\u00C2\u00A0 1.6\u00C2\u00A0 .1133\u00C2\u00A0 0.7\u00C2\u00A0 5.04\u00C2\u00A0 0.9\u00C2\u00A0 .3225\u00C2\u00A0 0.6\u00C2\u00A0 .685\u00C2\u00A0 15\u00C2\u00A0 0.000059\u00C2\u00A0 17\u00C2\u00A0 .053\u00C2\u00A0 1.5\u00C2\u00A0 .146\u00C2\u00A0 1.6\u00C2\u00A0 12\u00C2\u00A0 126\u00C2\u00A0 0.47\u00C2\u00A0 .057\u00C2\u00A0 0.6\u00C2\u00A0 23.0\u00C2\u00A0 357.2\u00C2\u00A0 2.0\u00C2\u00A0 .0520\u00C2\u00A0 1.5\u00C2\u00A0 0.41\u00C2\u00A0 1.6\u00C2\u00A0 .0569\u00C2\u00A0 0.6\u00C2\u00A0 .350\u00C2\u00A0 16\u00C2\u00A0 0.000012\u00C2\u00A0 30\u00C2\u00A0 .101\u00C2\u00A0 0.4\u00C2\u00A0 .013\u00C2\u00A0 2.2\u00C2\u00A0 153\u00C2\u00A0 236\u00C2\u00A0 0.05\u00C2\u00A0 .205\u00C2\u00A0 0.2\u00C2\u00A0 593.3\u00C2\u00A0 172.6\u00C2\u00A0 4.7\u00C2\u00A0 .1007\u00C2\u00A0 0.4\u00C2\u00A0 2.85\u00C2\u00A0 0.5\u00C2\u00A0 .2052\u00C2\u00A0 0.2\u00C2\u00A0 .397\u00C2\u00A0 17\u00C2\u00A0 0.000042\u00C2\u00A0 35\u00C2\u00A0 .099\u00C2\u00A0 0.7\u00C2\u00A0 .135\u00C2\u00A0 1.1\u00C2\u00A0 109\u00C2\u00A0 75\u00C2\u00A0 0.44\u00C2\u00A0 .284\u00C2\u00A0 0.6\u00C2\u00A0 62.0\u00C2\u00A0 611.8\u00C2\u00A0 8.9\u00C2\u00A0 .0982\u00C2\u00A0 0.7\u00C2\u00A0 3.84\u00C2\u00A0 0.9\u00C2\u00A0 .2836\u00C2\u00A0 0.6\u00C2\u00A0 .608\u00C2\u00A0 18\u00C2\u00A0 0.000025\u00C2\u00A0 45\u00C2\u00A0 .053\u00C2\u00A0 0.9\u00C2\u00A0 .100\u00C2\u00A0 1.2\u00C2\u00A0 23\u00C2\u00A0 571\u00C2\u00A0 0.32\u00C2\u00A0 .060\u00C2\u00A0 0.4\u00C2\u00A0 54.5\u00C2\u00A0 377.7\u00C2\u00A0 1.4\u00C2\u00A0 .0528\u00C2\u00A0 1.0\u00C2\u00A0 0.44\u00C2\u00A0 1.1\u00C2\u00A0 .0602\u00C2\u00A0 0.4\u00C2\u00A0 .348\u00C2\u00A0 19\u00C2\u00A0 0.000044\u00C2\u00A0 66\u00C2\u00A0 .061\u00C2\u00A0 1.7\u00C2\u00A0 .138\u00C2\u00A0 2.0\u00C2\u00A0 73\u00C2\u00A0 180\u00C2\u00A0 0.42\u00C2\u00A0 .101\u00C2\u00A0 0.8\u00C2\u00A0 5.5\u00C2\u00A0 618.1\u00C2\u00A0 4.9\u00C2\u00A0 .0605\u00C2\u00A0 1.8\u00C2\u00A0 0.84\u00C2\u00A0 2.0\u00C2\u00A0 .1006\u00C2\u00A0 0.8\u00C2\u00A0 .398\u00C2\u00A0 20\u00C2\u00A0 0.000165\u00C2\u00A0 40\u00C2\u00A0 .056\u00C2\u00A0 2.9\u00C2\u00A0 .272\u00C2\u00A0 2.4\u00C2\u00A0 61\u00C2\u00A0 666\u00C2\u00A0 0.84\u00C2\u00A0 .086\u00C2\u00A0 1.3\u00C2\u00A0 5.5\u00C2\u00A0 532.9\u00C2\u00A0 6.6\u00C2\u00A0 .0534\u00C2\u00A0 3.6\u00C2\u00A0 0.63\u00C2\u00A0 3.8\u00C2\u00A0 .0857\u00C2\u00A0 1.3\u00C2\u00A0 .334\u00C2\u00A0 21\u00C2\u00A0 0.000208\u00C2\u00A0 66\u00C2\u00A0 .047\u00C2\u00A0 4.0\u00C2\u00A0 .188\u00C2\u00A0 3.7\u00C2\u00A0 975\u00C2\u00A0 432\u00C2\u00A0 0.62\u00C2\u00A0 .002\u00C2\u00A0 1.2\u00C2\u00A0 3.5\u00C2\u00A0 15.9\u00C2\u00A0 0.2\u00C2\u00A0 .0437\u00C2\u00A0 6.4\u00C2\u00A0 0.01\u00C2\u00A0 6.5\u00C2\u00A0 .0025\u00C2\u00A0 1.2\u00C2\u00A0 .186\u00C2\u00A0 22\u00C2\u00A0 0.000071\u00C2\u00A0 40\u00C2\u00A0 .112\u00C2\u00A0 1.4\u00C2\u00A0 .545\u00C2\u00A0 1.2\u00C2\u00A0 82\u00C2\u00A0 289\u00C2\u00A0 1.79\u00C2\u00A0 .331\u00C2\u00A0 1.3\u00C2\u00A0 13.4\u00C2\u00A0 1847.7\u00C2\u00A0 23.9\u00C2\u00A0 .1108\u00C2\u00A0 1.5\u00C2\u00A0 5.06\u00C2\u00A0 1.9\u00C2\u00A0 .3310\u00C2\u00A0 1.3\u00C2\u00A0 .656\u00C2\u00A0 23\u00C2\u00A0 0.000034\u00C2\u00A0 27\u00C2\u00A0 .059\u00C2\u00A0 1.0\u00C2\u00A0 .187\u00C2\u00A0 1.0\u00C2\u00A0 327\u00C2\u00A0 943\u00C2\u00A0 0.59\u00C2\u00A0 .094\u00C2\u00A0 0.5\u00C2\u00A0 46.4\u00C2\u00A0 582.6\u00C2\u00A0 2.6\u00C2\u00A0 .0581\u00C2\u00A0 1.0\u00C2\u00A0 0.76\u00C2\u00A0 1.1\u00C2\u00A0 .0944\u00C2\u00A0 0.5\u00C2\u00A0 .405\u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Figu geochronology\u00C2\u00A0samples.\u00C2\u00A0 re\u00C2\u00A0A2.\u00C2\u00A0\u00C2\u00A0Regional\u00C2\u00A0geologic\u00C2\u00A0map\u00C2\u00A0of\u00C2\u00A0northwestern\u00C2\u00A0Per\u00C3\u00BA\u00C2\u00A0showing\u00C2\u00A0the\u00C2\u00A0location\u00C2\u00A0of\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0zircon\u00C2\u00A0 Appendix\u00C2\u00A0A\u00C2\u00A0 Pag 2 \u00C2\u00A0e\u00C2\u00A0 22\u00C2\u00A0 \u00C2\u00A070 80 90 100 110 20 6 P b/ 23 8 U a ge (M a) box heights are 2\u00CF\u0083 Age = 78.7 \u00C2\u00B1 1.4 (MSWD = 3.2) \u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A0A3.\u00C2\u00A0\u00C2\u00A0Box\u00C2\u00A0plot\u00C2\u00A0for\u00C2\u00A0all\u00C2\u00A0sample\u00C2\u00A0points\u00C2\u00A0for\u00C2\u00A0sample\u00C2\u00A0LW\u00E2\u0080\u009030\u00C2\u00A0illustrating\u00C2\u00A0207Pb\u00E2\u0080\u0090corrected\u00C2\u00A0 206Pb*/238U\u00C2\u00A0data\u00C2\u00A0with\u00C2\u00A0error\u00C2\u00A0bars\u00C2\u00A0at\u00C2\u00A02\u00CF\u0083.\u00C2\u00A0\u00C2\u00A0Open\u00C2\u00A0boxes\u00C2\u00A0are\u00C2\u00A0omitted\u00C2\u00A0whereas\u00C2\u00A0solid\u00C2\u00A0boxes\u00C2\u00A0were\u00C2\u00A0 included\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0age\u00C2\u00A0calculation.\u00C2\u00A0\u00C2\u00A0Ages\u00C2\u00A0given\u00C2\u00A0are\u00C2\u00A0206Pb/238U\u00C2\u00A0with\u00C2\u00A02\u00CF\u0083\u00C2\u00A0uncertainties.\u00C2\u00A0 \u00C2\u00A0 70 80 90 100 110 20 6 P b/ 23 8 U a ge (M a) Age = 88.1 \u00C2\u00B1 1.4 (MSWD = 8.5) box heights are 2\u00CF\u0083 \u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A0A4.\u00C2\u00A0\u00C2\u00A0Box\u00C2\u00A0plot\u00C2\u00A0for\u00C2\u00A0all\u00C2\u00A0sample\u00C2\u00A0points\u00C2\u00A0for\u00C2\u00A0sample\u00C2\u00A0LW\u00E2\u0080\u009031\u00C2\u00A0illustrating\u00C2\u00A0207Pb\u00E2\u0080\u0090corrected\u00C2\u00A0 206Pb*/238U\u00C2\u00A0data\u00C2\u00A0with\u00C2\u00A0error\u00C2\u00A0bars\u00C2\u00A0at\u00C2\u00A02\u00CF\u0083.\u00C2\u00A0\u00C2\u00A0Open\u00C2\u00A0boxes\u00C2\u00A0are\u00C2\u00A0omitted\u00C2\u00A0whereas\u00C2\u00A0solid\u00C2\u00A0boxes\u00C2\u00A0were\u00C2\u00A0 included\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0age\u00C2\u00A0calculation.\u00C2\u00A0\u00C2\u00A0Ages\u00C2\u00A0given\u00C2\u00A0are\u00C2\u00A0206Pb/238U\u00C2\u00A0with\u00C2\u00A02\u00CF\u0083\u00C2\u00A0uncertainties.\u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0A\u00C2\u00A0 Page\u00C2\u00A0223\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A00 200 400 600 800 1000 1200 20 6 P b/ 23 8 U a ge (M a) box heights are 2\u00CF\u0083 Age 230.2 \u00C2\u00B1 2.9 (MSWD = 65) \u00C2\u00A0 Figure\u00C2\u00A0A5.\u00C2\u00A0\u00C2\u00A0Box\u00C2\u00A0plot\u00C2\u00A0for\u00C2\u00A0all\u00C2\u00A0sample\u00C2\u00A0points\u00C2\u00A0for\u00C2\u00A0sample\u00C2\u00A03763\u00C2\u00A0illustrating\u00C2\u00A0207 \u00E2\u0080\u0090corrected\u00C2\u00A0 s re\u00C2\u00A0 included\u00C2\u00A0 s\u00C2\u00A0 Pb 206Pb*/238U\u00C2\u00A0data\u00C2\u00A0with\u00C2\u00A0error\u00C2\u00A0bars\u00C2\u00A0at\u00C2\u00A02\u00CF\u0083.\u00C2\u00A0\u00C2\u00A0Open\u00C2\u00A0boxes\u00C2\u00A0are\u00C2\u00A0omitted\u00C2\u00A0wherea \u00C2\u00A0solid\u00C2\u00A0boxes\u00C2\u00A0we in\u00C2\u00A0the\u00C2\u00A0age\u00C2\u00A0calculation\u00C2\u00A0(and\u00C2\u00A0are\u00C2\u00A0noted\u00C2\u00A0by\u00C2\u00A0those\u00C2\u00A0encircled\u00C2\u00A0with\u00C2\u00A0the\u00C2\u00A0dashed\u00C2\u00A0line).\u00C2\u00A0\u00C2\u00A0Age given\u00C2\u00A0are\u00C2\u00A0206Pb/238U\u00C2\u00A0with\u00C2\u00A02\u00CF\u0083\u00C2\u00A0uncertainties.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 0 500 1000 1500 2000 2500 20 6 P b/ 23 8 U a ge (M a) box heights are 2\u00CF\u0083 \u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A0A6.\u00C2\u00A0\u00C2\u00A0Box\u00C2\u00A0plot\u00C2\u00A0for\u00C2\u00A0all\u00C2\u00A0sample\u00C2\u00A0points\u00C2\u00A0for\u00C2\u00A0sample\u00C2\u00A01601\u00C2\u00A0illustrating\u00C2\u00A0207Pb\u00E2\u0080\u0090corrected\u00C2\u00A0 206Pb*/238U\u00C2\u00A0data\u00C2\u00A0with\u00C2\u00A0error\u00C2\u00A0bars\u00C2\u00A0at\u00C2\u00A02\u00CF\u0083.\u00C2\u00A0\u00C2\u00A0No\u00C2\u00A0age\u00C2\u00A0was\u00C2\u00A0determined\u00C2\u00A0for\u00C2\u00A0this\u00C2\u00A0sample,\u00C2\u00A0though\u00C2\u00A0the\u00C2\u00A0 circled\u00C2\u00A0data\u00C2\u00A0points\u00C2\u00A0represent\u00C2\u00A0possible\u00C2\u00A0igneous\u00C2\u00A0age\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0sample.\u00C2\u00A0\u00C2\u00A0Ages\u00C2\u00A0given\u00C2\u00A0are\u00C2\u00A0206 238Pb/ U\u00C2\u00A0with\u00C2\u00A0 \u00CF\u0083\u00C2\u00A0uncertainties.\u00C2\u00A02 Appendix\u00C2\u00A0A\u00C2\u00A0 Page\u00C2\u00A0224\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0Appendix\u00C2\u00A0A\u00C2\u00A0 Page\u00C2\u00A0225\u00C2\u00A0 \u00C2\u00A0 A.4\u00C2\u00A0 References\u00C2\u00A0 Chiaradia,\u00C2\u00A0M.,\u00C2\u00A0Fontbote,\u00C2\u00A0L.,\u00C2\u00A0and\u00C2\u00A0Paladines,\u00C2\u00A0A.\u00C2\u00A0\u00C2\u00A02004.\u00C2\u00A0\u00C2\u00A0Metal\u00C2\u00A0sources\u00C2\u00A0in\u00C2\u00A0mineral\u00C2\u00A0deposits\u00C2\u00A0and\u00C2\u00A0 crustal\u00C2\u00A0rocks\u00C2\u00A0of\u00C2\u00A0Ecuador\u00C2\u00A0(1\u00C2\u00A0degrees\u00C2\u00A0N\u00E2\u0080\u00904\u00C2\u00A0degrees\u00C2\u00A0S);\u00C2\u00A0a\u00C2\u00A0lead\u00C2\u00A0isotope\u00C2\u00A0synthesis,\u00C2\u00A0Economic\u00C2\u00A0 Geology\u00C2\u00A0and\u00C2\u00A0the\u00C2\u00A0Bulletin\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0Economic\u00C2\u00A0Geologists,\u00C2\u00A099:\u00C2\u00A01085\u00E2\u0080\u00901106.\u00C2\u00A0 \u00C2\u00A0 Krogh,\u00C2\u00A0T.E.\u00C2\u00A0\u00C2\u00A01982.\u00C2\u00A0\u00C2\u00A0Improved\u00C2\u00A0accuracy\u00C2\u00A0of\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0zircon\u00C2\u00A0ages\u00C2\u00A0by\u00C2\u00A0the\u00C2\u00A0creation\u00C2\u00A0of\u00C2\u00A0more\u00C2\u00A0concordant\u00C2\u00A0 systems\u00C2\u00A0using\u00C2\u00A0an\u00C2\u00A0air\u00C2\u00A0abrasion\u00C2\u00A0technique.\u00C2\u00A0Geochimica\u00C2\u00A0et\u00C2\u00A0Cosmochimica\u00C2\u00A0Acta,\u00C2\u00A046:\u00C2\u00A0637\u00E2\u0080\u0090649.\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Noble,\u00C2\u00A0S.R.,\u00C2\u00A0Aspden,\u00C2\u00A0J.A.,\u00C2\u00A0and\u00C2\u00A0Jemielita,\u00C2\u00A0R.A.\u00C2\u00A0\u00C2\u00A01997.\u00C2\u00A0\u00C2\u00A0Northern\u00C2\u00A0Andean\u00C2\u00A0crustal\u00C2\u00A0evolution;\u00C2\u00A0new\u00C2\u00A0U\u00E2\u0080\u0090 Pb\u00C2\u00A0geochronological\u00C2\u00A0constraints\u00C2\u00A0from\u00C2\u00A0Ecuador.\u00C2\u00A0Geological\u00C2\u00A0Society\u00C2\u00A0of\u00C2\u00A0America\u00C2\u00A0Bulletin,\u00C2\u00A0109:\u00C2\u00A0 789\u00E2\u0080\u0090798.\u00C2\u00A0 \u00C2\u00A0 Mortensen,\u00C2\u00A0J.K.,\u00C2\u00A0Ghosh,\u00C2\u00A0D.,\u00C2\u00A0and\u00C2\u00A0Ferri,\u00C2\u00A0F.\u00C2\u00A0\u00C2\u00A01995.\u00C2\u00A0\u00C2\u00A0U\u00E2\u0080\u0090Pb\u00C2\u00A0age\u00C2\u00A0constraints\u00C2\u00A0of\u00C2\u00A0intrusive\u00C2\u00A0rocks\u00C2\u00A0 associated\u00C2\u00A0with\u00C2\u00A0Copper\u00E2\u0080\u0090Gold\u00C2\u00A0porphyry\u00C2\u00A0deposits\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Canadian\u00C2\u00A0Cordillera,\u00C2\u00A0in\u00C2\u00A0Schroeter,\u00C2\u00A0T.G.,\u00C2\u00A0 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All\u00C2\u00A0analyses\u00C2\u00A0reported\u00C2\u00A0were\u00C2\u00A0performed\u00C2\u00A0on\u00C2\u00A0hornblende\u00C2\u00A0mineral\u00C2\u00A0separates.\u00C2\u00A0\u00C2\u00A0Several\u00C2\u00A0feldspar\u00C2\u00A0 and\u00C2\u00A0biotite\u00C2\u00A0mineral\u00C2\u00A0separates\u00C2\u00A0were\u00C2\u00A0analyzed\u00C2\u00A0but\u00C2\u00A0yielded\u00C2\u00A0more\u00C2\u00A0variable\u00C2\u00A0results.\u00C2\u00A0\u00C2\u00A0Sample\u00C2\u00A0LW\u00E2\u0080\u009006,\u00C2\u00A0 a\u00C2\u00A0hornblende\u00C2\u00A0granodiorite\u00C2\u00A0pluton\u00C2\u00A0exposed\u00C2\u00A0for\u00C2\u00A0several\u00C2\u00A0kilometres\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0western\u00C2\u00A0sector\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 map\u00C2\u00A0area,\u00C2\u00A0yielded\u00C2\u00A0a\u00C2\u00A0plateau\u00C2\u00A0age\u00C2\u00A0of\u00C2\u00A047.1\u00C2\u00A0\u00C2\u00B1\u00C2\u00A03.1\u00C2\u00A0Ma\u00C2\u00A0with\u00C2\u00A0MSWD\u00C2\u00A0of\u00C2\u00A00.85\u00C2\u00A0using\u00C2\u00A0100%\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A039Ar\u00C2\u00A0 (Fig.\u00C2\u00A0B2).\u00C2\u00A0\u00C2\u00A0Located\u00C2\u00A0close\u00C2\u00A0to\u00C2\u00A0LW\u00E2\u0080\u009006,\u00C2\u00A0sample\u00C2\u00A0LW\u00E2\u0080\u009007\u00C2\u00A0was\u00C2\u00A0collected\u00C2\u00A0from\u00C2\u00A0a\u00C2\u00A0volcaniclastic\u00C2\u00A0unit\u00C2\u00A0and\u00C2\u00A0 yielded\u00C2\u00A0a\u00C2\u00A0plateau\u00C2\u00A0age\u00C2\u00A0of\u00C2\u00A048.6\u00C2\u00A0\u00C2\u00B1\u00C2\u00A07.4\u00C2\u00A0Ma\u00C2\u00A0with\u00C2\u00A0MSWD\u00C2\u00A0of\u00C2\u00A01.3\u00C2\u00A0using\u00C2\u00A075%\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A039Ar\u00C2\u00A0(Fig.\u00C2\u00A0B3).\u00C2\u00A0\u00C2\u00A0The\u00C2\u00A0 age\u00C2\u00A0is\u00C2\u00A0interpreted\u00C2\u00A0as\u00C2\u00A0a\u00C2\u00A0reset\u00C2\u00A0due\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0thermal\u00C2\u00A0effects\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0proximal\u00C2\u00A0granodiorite\u00C2\u00A0intrusion.\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Sample\u00C2\u00A0LW\u00E2\u0080\u009036\u00C2\u00A0(hornblende\u00C2\u00A0diorite)\u00C2\u00A0is\u00C2\u00A0located\u00C2\u00A0approximately\u00C2\u00A010\u00C2\u00A0km\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0east\u00C2\u00A0of\u00C2\u00A0samples\u00C2\u00A0 LW\u00E2\u0080\u009006\u00C2\u00A0and\u00C2\u00A0\u00E2\u0080\u009007,\u00C2\u00A0and\u00C2\u00A0very\u00C2\u00A0similar\u00C2\u00A0in\u00C2\u00A0composition\u00C2\u00A0as\u00C2\u00A0LW\u00E2\u0080\u009006.\u00C2\u00A0\u00C2\u00A0This\u00C2\u00A0sample\u00C2\u00A0produced\u00C2\u00A0a\u00C2\u00A0plateau\u00C2\u00A0age\u00C2\u00A0 of\u00C2\u00A052.2\u00C2\u00A0Ma\u00C2\u00A0\u00C2\u00B1\u00C2\u00A03.4\u00C2\u00A0Ma\u00C2\u00A0with\u00C2\u00A0MSWD\u00C2\u00A0of\u00C2\u00A00.99\u00C2\u00A0including\u00C2\u00A096%\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A039Ar\u00C2\u00A0(Fig.\u00C2\u00A0B4).\u00C2\u00A0\u00C2\u00A0Sample\u00C2\u00A0LW\u00E2\u0080\u009088,\u00C2\u00A0a\u00C2\u00A0 hornblende\u00C2\u00A0porphyry\u00C2\u00A0dyke\u00C2\u00A0northeast\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Los\u00C2\u00A0Lomas\u00C2\u00A0batholith,\u00C2\u00A0yielded\u00C2\u00A0a\u00C2\u00A0similar\u00C2\u00A0but\u00C2\u00A0less\u00C2\u00A0 precise\u00C2\u00A0plateau\u00C2\u00A0age\u00C2\u00A0of\u00C2\u00A055.0\u00C2\u00A0Ma\u00C2\u00A0\u00C2\u00B1\u00C2\u00A03.8\u00C2\u00A0Ma\u00C2\u00A0with\u00C2\u00A0MSWD\u00C2\u00A0of\u00C2\u00A01.7\u00C2\u00A0factoring\u00C2\u00A0in\u00C2\u00A044%\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A039Ar\u00C2\u00A0(Fig.\u00C2\u00A0B5).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Sample\u00C2\u00A0LW\u00E2\u0080\u009085\u00C2\u00A0is\u00C2\u00A0a\u00C2\u00A0hornblende\u00C2\u00A0granite\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0Los\u00C2\u00A0Lomas\u00C2\u00A0batholith\u00C2\u00A0and\u00C2\u00A0yields\u00C2\u00A0a\u00C2\u00A0plateau\u00C2\u00A0age\u00C2\u00A0 of\u00C2\u00A072.4\u00C2\u00A0Ma\u00C2\u00A0\u00C2\u00B1\u00C2\u00A03.4\u00C2\u00A0Ma\u00C2\u00A0with\u00C2\u00A0MSWD\u00C2\u00A0of\u00C2\u00A01.4\u00C2\u00A0including\u00C2\u00A095.5%\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A039Ar\u00C2\u00A0(Fig.\u00C2\u00A0B6).\u00C2\u00A0\u00C2\u00A0A\u00C2\u00A0similar\u00C2\u00A0age\u00C2\u00A0was\u00C2\u00A0 determined\u00C2\u00A0from\u00C2\u00A0LW\u00E2\u0080\u009061,\u00C2\u00A0a\u00C2\u00A0hornblende\u00C2\u00A0and\u00C2\u00A0plagiclase\u00C2\u00A0porphyritic\u00C2\u00A0dyke\u00C2\u00A0southeast\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0 batholith.\u00C2\u00A0\u00C2\u00A0LW\u00E2\u0080\u009061\u00C2\u00A0yielded\u00C2\u00A0a\u00C2\u00A0plateau\u00C2\u00A0age\u00C2\u00A0of\u00C2\u00A074.9\u00C2\u00A0Ma\u00C2\u00A0\u00C2\u00B1\u00C2\u00A03.3\u00C2\u00A0Ma\u00C2\u00A0with\u00C2\u00A0MSWD\u00C2\u00A0of\u00C2\u00A01.4\u00C2\u00A0including\u00C2\u00A097.3%\u00C2\u00A0 of\u00C2\u00A0the\u00C2\u00A039Ar\u00C2\u00A0(Fig.\u00C2\u00A07).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 t \u00C2\u00A0Appendix\u00C2\u00A0B\u00C2\u00A0 \u00C2\u00A0 page\u00C2\u00A0228\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Zone\u00C2\u00A017,\u00C2\u00A0Southern\u00C2\u00A0Hemisphere\u00C2\u00A0(WGS84).\u00C2\u00A0 Sample Rock Type Analyzed Easting Northing \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Table\u00C2\u00A0B1.\u00C2\u00A0\u00C2\u00A040Ar\u00E2\u0080\u009039Ar\u00C2\u00A0rock\u00C2\u00A0sample\u00C2\u00A0description\u00C2\u00A0and\u00C2\u00A0location\u00C2\u00A0data.\u00C2\u00A0\u00C2\u00A0Eastings\u00C2\u00A0and\u00C2\u00A0northings\u00C2\u00A0are\u00C2\u00A0UTM \u00C2\u00A0 Mineral LW-06 hornblende granodiorite hornblende 559404 9481200 LW-07 hornblende-plagioclase +/- (volcaniclastic) hornblende 560758 9483392 quartz porphyritic rhyolite LW-36 hornblende-bearing diorite hornblende 567854 9479640 LW LW-85 hornblende-bearing granite hornblende 581496 9485511 -88 hornblende porphyry dyke hornblende 588812 9490854 LW-61 hornblende-plagioclase porphyry dyke hornblende 584704 9466924 \u00C2\u00A0 \u00C2\u00A0 Laser1 Isotope Ratios Power (%) 40Ar/39Ar 38Ar/39Ar 37Ar/39Ar Ca/K l/K %40 39Ar 40Ar*/39ArK Age\u00C2\u00B12\u00CF\u0083 LW-06 (granodiorite), hornblende, J = 0.008961\u00C2\u00B10.000016; volume 39ArK = 68.82 x 10-10cm3, integrated age = 4 Ma (2\u00CF\u0083) C Ar % 8.06\u00C2\u00B15.81 36Ar/39Ar 2 179.290\u00C2\u00B10.041 0.524\u00C2\u00B10.088 0.555\u00C2\u00B10.041 0.093 1 1.42-2.913\u00C2\u00B19.923 -47.72\u00C2\u00B1164.71 2.5 53.563 0.020 0.186 0.038 0.118 0.024 0.032 6.953.852 3.183 61.22 49.74 3 20.973 0.014 0.512 0.018 0.127 0.020 0.113 6.53.650 1.316 58.07 20.60 3.7 12.038 0.010 2.298 0.014 0.027 0.637 0.525 41.123.154 0.423 50.28 6.64 3.7 10.434 0.014 2.338 0.019 0.054 0.326 0.535 33.012.873 0.234 45.86 3.69 3.9 42.628 0.023 2.022 0.042 0.307 0.023 0.462 2.594.238 2.680 67.24 41.74 4.2 27.371 0.046 2.613 0.047 0.222 0.052 0.599 4.212.351 2.589 37.61 41.00 5.5 28.936 0.024 3.496 0.028 0.202 0.039 0.803 4.212.271 1.715 36.34 27.17 LW-07 (rhyolitic volcaniclastic), hornblende, J = 0.008959\u00C2\u00B10.000016; v = 10-10cm3, integrate 0.29\u00C2\u00B17.66 Ma (2\u00CF\u0083) 2 84.108\u00C2\u00B10.033 0.116\u00C2\u00B10.092 0.328\u00C2\u00B10.048 0.281\u00C2\u00B10.062 1.095 0.012 2.842.298\u00C2\u00B14.463 36.76\u00C2\u00B170.68 2.3 57.582 0.032 0.085 0.117 0.218 0.399 0.204 0.065 2.431 0.008 10 4.86-1.962 3.635 -31.99 59.80 2.6 55.344 0.049 0.168 0.072 0.333 0.390 0 6 119. 3.49-9.606 4.926 -162.34 87.11 2.9 56.241 0.062 0.673 0.080 0.534 0.112 0 5 115.8 1.94-7.331 5.689 -122.56 98.42 3.2 14.654 0.026 2.293 0.033 0.092 0.051 0 4 84.5 11.81.955 0.693 31.33 11.01 3.4 14.165 0.023 2.610 0.033 0.088 0.172 0 0.598 76.0 14.283.004 1.114 47.91 17.54 3.6 10.680 0.021 2.418 0.029 0.058 0.143 0.025 0.109 1.208 0.553 62.3 21.833.613 0.814 57.47 12.74 3.8 10.875 0.019 2.463 0.019 0.058 0.133 0.028 0.099 1.175 0.564 67.9 21.853.141 0.806 50.06 12.67 4 20.564 0.033 2.652 0.033 0.164 0.108 0 0.608 89.6 7.051.790 1.756 28.70 27.93 4.3 34.468 0.030 3.272 0.035 0.305 0.097 0 0.753 96.6 3.260.908 3.429 14.62 54.97 4.8 26.172 0.038 3.663 0.041 0.217 0.070 0 0.843 9 4.681.489 2.168 23.91 34.58 6 45.223 0.057 3.231 0.061 0.447 0.060 0.155 0.109 2.33 0.745 95.1 2.131.689 4.356 27.10 69.36 0.6 0.1 0.0 0.0 0.0 0.1 0.0 0.0 22 69 60 31 27 35 88 94 olum \u00C2\u00B10.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0 e 39 66 66 74 46 31 69 06 65 ArK 1 0 0 0 2 0 1 59.67 x .26 .47 .56 .55 .10 .773 2.74 .328 4 7 3 2 6 01.71 92.38 79.71 72.47 70.56 88.07 89.68 90.66 d age = 3 96.99 3.62 3 8 3 4 9 2 4 6 3 8 .223 .222 .045 .040 0.0 0.1 0.0 0.0 87 04 57 97 5.60 5.73 1.12 1.822 1 0.02 7 0.14 4 0.52 .066 .119 .088 0.0 0.1 0.0 93 01 91 2.58 2.35 1.868 5 3 \u00C2\u00A0 \u00C2\u00A0 Table\u00C2\u00A0B2.\u00C2\u00A0\u00C2\u00A040Ar\u00E2\u0080\u009039Ar\u00C2\u00A0age\u00C2\u00A0data\u00C2\u00A0for\u00C2\u00A0plutonic\u00C2\u00A0and\u00C2\u00A0volcanic\u00C2\u00A0rock m e\u00C2\u00A0 \u00C2\u00A0basin.\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0flux\u00C2\u00A0monitors:\u00C2\u00A024.36\u00C2\u00A0Ma\u00C2\u00A0MAC\u00E2\u0080\u009083\u00C2\u00A0 biotite\u00C2\u00A0(Sandeman\u00C2\u00A0et\u00C2\u00A0al.\u00C2\u00A01999);\u00C2\u00A028.02\u00C2\u00A0Ma\u00C2\u00A0FCs\u00C2\u00A0(Renne\u00C2\u00A0et\u00C2\u00A0al. 9 \u00C2\u00A0 \u00C2\u00A0ratios:\u00C2\u00A0(40 39Ar)K=0.0302,\u00C2\u00A0(37Ar/39Ar)Ca=1416.4306,\u00C2\u00A0 (36Ar/39Ar)Ca=0.3952,\u00C2\u00A0Ca/K=1.83(37ArCa/39ArK). \u00C2\u00A0sa ,\u00C2\u00A019 ple 8). s\u00C2\u00A0f \u00C2\u00A0\u00C2\u00A0Is ro oto m\u00C2\u00A0th pe Lancones Neutron Ar/production Appendix\u00C2\u00A0B\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 page\u00C2\u00A0229\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Laser1 Isotope Ratios Power 40Ar/39Ar 38Ar/ Ar Ar/ Ar 36Ar/39Ar Cl/K % Ar % Ar Ar*/39ArK Age\u00C2\u00B12\u00CF\u0083 W (diorite 0.0 = 119 3 d (%) 39 37 39 Ca/K 40 39 40 L -36 ), hornblende, J = 08957\u00C2\u00B10.000014; volume 39ArK .09 x 10-10cm , integrate age = 45.60\u00C2\u00B15.34 Ma (2\u00CF\u0083) 2807.088\u00C2\u00B10.133 4.622\u00C2\u00B10.148 4.732\u00C2\u00B10.133 3.176\u00C2\u00B10.159 18.431 1.1 116.3 0.08-134.518\u00C2\u00B197.834 2.3 1 1.4 1. 6 01 0.41 0. 0.4 1. 1 10 1.3 2.9 0. 0.3 0. 1 02.8 2.25-2 0. 0.2 1. 0 97.5 2.08 0. 0.1 0. 0 93.5 4.38 0. 0.0 0. 3 80.8 29.6 0. 0.0 0.27 3 79.6 4.63 0. 0.0 1. 4 73.3 9.48 4.412.268 0.015 2.086 0.022 0.061 0.073 0.033 0.050 1.342 0.477 74.52 10.712.837 0.479 5.27 7.54 0 52.82 11.66 5. 0. 0.0 1. 5 77.2 5.53 W-8 hyritic d nde, 0. 39ArK x m3, i ed ag (2\u00CF\u0083) 41.196 0.085 107.03 0.01 2 0.024 103.94 0.18 0.005 95.06 0.79 0.006 92.22 1.68 0.005 94.42 2.32 3.4 0.006 97.04 2.43 0.005 91.4 2.4 0.007 85.14 3.58 4.5 0.872 0.094 81.91 7.83 5.510.698 0.011 1.195 0.014 0.011 1.156 0.024 0.040 0.516 0.271 65.26 32.173.606 0.286 57.29 4.48 6.58.140 0.011 0.575 0.013 0.006 0.523 0.014 0.028 0.242 0.129 47.85 46.614.131 0.130 65.48 2.03 420.678 0.295 2.883 0.300 .080 0.295 58 0.301 792 0. 21 1 .78 -7.308 28.118 -122.14 486.20 2.6129.388 0.058 0.801 0.065 363 0.061 54 0.087 624 0. 64 3 -3.700 8.991 -60.81 150.27 88.059 0.038 0.517 0.045 210 0.041 08 0.057 835 0. 04 1 8 .439 4.031 -39.85 66.59 3.271.519 0.033 0.372 0.063 239 0.037 39 0.076 737 0. 73 5 1.601 4.878 25.69 77.72 3.538.914 0.031 0.363 0.049 113 0.038 25 0.062 752 0. 75 2 2.337 2.003 37.37 31.71 3.818.493 0.011 1.742 0.014 026 0.854 52 0.022 785 0. 96 5 3.436 0.313 54.69 4.91 418.810 0.021 1.437 0.025 035 0.046 52 0.051 8 0. 26 4 1 3.645 0.738 57.95 11.54 4.212.455 0.014 1.998 0.023 041 0.123 33 0.078 261 0. 56 5 1 3.138 0.742 50.01 11.66 4.813.818 0.017 2.141 0.018 0.051 0.025 0.037 0.068 0.279 .489 73.6 9.543.317 0.743 4 516.820 0.023 2.228 0.025 105 0.055 48 0.070 678 0. 09 2 3.360 0.981 53.50 15.40 L 8 (hornblende porp yke), hornble J = 0.008948\u00C2\u00B1 000016; volume = 235.18 10-10c ntegrat e = 56.86\u00C2\u00B12.77 Ma 24172.030\u00C2\u00B10.287 3.098\u00C2\u00B10.304 5.441\u00C2\u00B10.288 15.269\u00C2\u00B10.290 -475.602\u00C2\u00B1321.56 2.3351.623 0.046 0.352 0.066 0.676 0.054 1.262 0.074 4.794 -13.108 22.908 -225.07 418.93 2.683.108 0.039 0.087 0.129 0.160 0.061 0.276 0.077 1.346 3.699 5.803 58.74 90.68 2.956.227 0.016 0.073 0.059 0.085 0.087 0.180 0.049 1.308 4.052 2.640 64.26 41.12 3.241.108 0.031 0.061 0.108 0.063 0.063 0.134 0.079 1.022 2.107 2.891 33.69 45.80 30.804 0.013 0.057 0.067 0.065 0.092 0.104 0.069 1.298 0.800 2.104 12.87 33.72 3.629.437 0.024 0.052 0.106 0.054 0.143 0.094 0.052 0.483 2.263 1.318 36.17 20.85 3.923.220 0.022 0.058 0.056 0.039 0.275 0.069 0.046 0.517 3.143 0.857 50.04 13.45 18.237 0.020 0.431 0.028 0.027 0.116 0.052 0.038 3.111 0.508 49.54 7.98 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Table\u00C2\u00A0B2\u00C2\u00A0continued. Appendix\u00C2\u00A0B\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 page\u00C2\u00A0230\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0Appendix\u00C2\u00A0B\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 page\u00C2\u00A0231\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Laser1 Isotope Ratios ower (%) Ar 39Ar K Ar r*/39ArK \u00CF\u0083 LW-85 (gran 0.00 4; 27 3, integr e 4\u00C2\u00B11. a (2\u00CF\u0083 P 40Ar/39Ar 38Ar/39Ar 37Ar/39 36Ar/ Ca/K Cl/ %40 %39Ar 40A Age\u00C2\u00B12 ite), hornblende, J = 8954\u00C2\u00B10.00001 volume 39Ar =K 3.18 x 10-10cm ated ag = 70.8 91 M ) 0 6 57 93 14 04.4 .955 120.15 2 0 84 39 083 5.83 .794 .18 2 0 44 .3 062 6.33 .992 .57 2 1 93 42 .24 9.38 .568 .53 3 1 32 19 436 5.19 .222 44 3 1 42 456 9.79 .161 50 3 2 64 462 1.36 .261 06 3 2 41 44 458 7.27 .176 73 .477 42.69 70.49 9.49 LW-61 (hornbl orph rn 08 olum x 3, int 1 Ma \u00CF\u0083) 3 84 78 3.72 67.377 \u00C2\u00B12117.39 2 1 73 256 5.26 58.106 446.85 2 1 00 249 0.06 9.862 2.29 2 1 32 452 8.34 14.924 271.14 3 3 09 731 80.5 .410 2.04 3 3 .8 745 46.7 .331 .12 3 3 56 738 2.11 .306 .74 3 3 83 742 53.3 .787 2.24 4 5 18 268 9.18 .310 2.16 1.725 1.233 92.74 2 180.329\u00C2\u00B10.044 .745\u00C2\u00B10.050 0.494\u00C2\u00B1 0.04 0.641\u00C2\u00B10.0 1. 6 0. 3 1 0.41-7.245\u00C2\u00B16 -121.01\u00C2\u00B1 .3 39.408 0.025 .394 0.040 0.102 0.029 0.118 0.0 0. 4 0. 8 1.985.054 2 79.85 43 .6 26.917 0.017 .296 0.030 0.093 0.024 0.082 0.0 0 1 0. 8 2.163.209 0 51.11 15 .9 20.263 0.016 .065 0.023 0.072 0.038 0.058 0.0 0. 9 0 7 2.873.648 1 57.98 24 72.16 3..2 .5 8 10.751 0.018 .910 0.020 0.016 0.292 0.022 0.0 0. 7 0. 5 14.094.557 0 .095 0.009 .997 0.012 -0.015 1.902 0.012 0.0 0 0. 3 36.124.717 0 74.63 2. .7 7.993 0.018 .022 0.019 ERR 0.013 0.0 0 0. 4 15.944.392 0 69.59 4. 72.10 2..9 7.791 0.017 .003 0.021 0.019 0.180 0.012 0.0 0. 5 0. 3 14.744.553 0 4.1 8.436 0.014 2.085 0.016 0.018 1.034 0.015 0.089 0 0 8.644.337 0.400 68.73 6.21 4.4 13.390 0.009 2.280 0.014 0.031 0.549 0.032 0.065 0 0.521 59.67 3.054.450 0.611 ende-plagioclase p yritic dyke), ho blende, J = 0.0 954\u00C2\u00B10.000014; v e 39Ar =K 15. 273.18 10-10cm egrated age = 70.84\u00C2\u00B11.9 (2 2 1318.31\u00C2\u00B10.09 .67\u00C2\u00B10.11 2.38\u00C2\u00B10.09 4.72\u00C2\u00B10.09 1 0. 2 10 0.1-54.262\u00C2\u00B1 -1200.38 .3 737.79 0.12 .40 0.14 2.67 0.13 2.74 0.13 11. 1 0. 10 0.09-39.216 -780.45 1 .6 594.23 0.08 .32 0.12 2.05 0.08 2.12 0.12 10. 4 0. 10 0.12-0.358 6 -5.79 113 .9 185.90 0.10 .98 0.11 0.92 0.10 0.71 0.12 8. 6 0. 10 0.32-12.368 -211.77 .2 24.20 0.03 .18 0.04 0.11 0.29 0.07 0.07 2. 8 0. 3.443.790 1 60.21 2 .5 9.60 0.02 .25 0.02 0.02 0.24 0.02 0.06 0 7 0. 32.294.811 0 76.09 5 .7 8.70 0.01 .22 0.02 0.01 0.19 0.01 0.07 0. 9 0. 4 42.254.778 0 75.58 4 .9 10.50 0.03 .23 0.02 0.03 0.88 0.02 0.11 0. 2 0. 16.274.406 0 69.81 1 .3 32.68 0.04 .49 0.04 0.13 0.06 0.11 0.11 1. 2 1. 8 2.432.808 3 44.80 5 5.5 28.46 0.03 5.34 0.03 0.13 0.22 0.10 0.06 2.71.613 1.466 25.87 23.35 \u00C2\u00A0 Table\u00C2\u00A0B2\u00C2\u00A0continued. \u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 Figure \u00C2\u00A0 is\u00C2\u00A0UTM\u00C2\u00A0Zone\u00C2\u00A017,\u00C2\u00A0Southern\u00C2\u00A0Hemisphere\u00C2\u00A0(WGS84).\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0B1\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0Geology\u00C2\u00A0map\u00C2\u00A0of\u00C2\u00A0study\u00C2\u00A0area\u00C2\u00A0showing\u00C2\u00A0the\u00C2\u00A0location\u00C2\u00A0of\u00C2\u00A0Ar\u00E2\u0080\u0090Ar\u00C2\u00A0samples.\u00C2\u00A0\u00C2\u00A0Map\u00C2\u00A0projection Appendix\u00C2\u00A0B\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 page\u00C2\u00A0232\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A00 20 40 60 80 100 120 0 20 40 60 80 100 Cumulative 39Ar Percent A ge (M a) Plateau age = 47.1 \u00C2\u00B1 3.1 Ma (2\u00CF\u0083, including J-error of .16%) MSWD = 0.85, probability=0.55 Includes 100% of the 39Ar Plateau steps are filled, rejected steps are open box heights are 2\u00CF\u0083 \u00C2\u00A0 Figure\u00C2\u00A0B2\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A0Step\u00E2\u0080\u0090heating\u00C2\u00A0cumulative\u00C2\u00A0percent\u00C2\u00A0of\u00C2\u00A039Ar\u00C2\u00A0released\u00C2\u00A0vs.\u00C2\u00A0age\u00C2\u00A0plot\u00C2\u00A0for\u00C2\u00A0sample\u00C2\u00A0LW\u00E2\u0080\u009006\u00C2\u00A0 (granodiorite).\u00C2\u00A0 \u00C2\u00A0 0 10 20 30 40 50 60 70 80 90 100 110 120 0 20 40 60 80 100 Cumulative 39Ar Percent A ge (M a) Plateau age = 48.6 \u00C2\u00B1 7.4 Ma (2\u00CF\u0083, including J-error of .16%) MSWD = 1.3, probability=0.24 Includes 75.1% of the 39Ar Plateau steps are filled, rejected steps are open box heights are 2\u00CF\u0083 \u00C2\u00A0 \u00C2\u00A0 igure\u00C2\u00A0B3\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0Step\u00E2\u0080\u0090heating\u00C2\u00A0cumulative\u00C2\u00A0percent\u00C2\u00A0of\u00C2\u00A039Ar\u00C2\u00A0released\u00C2\u00A0vs.\u00C2\u00A0age\u00C2\u00A0plot\u00C2\u00A0for\u00C2\u00A0sample\u00C2\u00A0LW\u00E2\u0080\u009007\u00C2\u00A0F (rhyolitic\u00C2\u00A0volcaniclastic)\u00C2\u00A0 Appendix\u00C2\u00A0B\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 page\u00C2\u00A0233\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A00 20 40 60 80 100 120 0 20 40 60 80 100 Cumulative 39Ar Percent A ge (M a) Plateau age = 52.2 \u00C2\u00B1 3.4 Ma (2\u00CF\u0083, including J-error of .16%) MSWD = 0.99, probability=0.44 Includes 96% of the 39Ar Plateau steps are filled, rejected steps are open box heights are 2\u00CF\u0083 \u00C2\u00A0 \u00C2\u00A0 39Figure\u00C2\u00A0B4\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A0Step\u00E2\u0080\u0090heating\u00C2\u00A0cumulative\u00C2\u00A0percent\u00C2\u00A0of\u00C2\u00A0 Ar\u00C2\u00A0released\u00C2\u00A0vs.\u00C2\u00A0age\u00C2\u00A0plot\u00C2\u00A0for\u00C2\u00A0sample\u00C2\u00A0LW\u00E2\u0080\u009036\u00C2\u00A0 (diorite).\u00C2\u00A0 \u00C2\u00A0 0 20 40 60 80 100 120 0 20 40 60 80 100 Cumulative 39Ar Percent A ge (M a) Plateau age = 55.0 \u00C2\u00B1 3.8 Ma (2\u00CF\u0083, including J-error of .16%) MSWD = 1.7, probability=0.18 Includes 43.6% of the 39Ar Plateau steps are filled, rejected steps are open box heights are 2\u00CF\u0083 \u00C2\u00A0 \u00C2\u00A0 igure\u00C2\u00A0B5\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0Step\u00E2\u0080\u0090heating\u00C2\u00A0cumulative\u00C2\u00A0percent\u00C2\u00A0of\u00C2\u00A039Ar\u00C2\u00A0released\u00C2\u00A0vs.\u00C2\u00A0age\u00C2\u00A0plot\u00C2\u00A0for\u00C2\u00A0sample\u00C2\u00A0LW\u00E2\u0080\u009088\u00C2\u00A0 \u00C2\u00A0 F (hornblende\u00C2\u00A0porphyritic\u00C2\u00A0dyke).\u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0B\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 page\u00C2\u00A0234\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A00 20 40 60 80 100 120 0 20 40 60 80 100 Cumulative 39Ar Percent A ge (M a) Plateau age = 72.4 \u00C2\u00B1 1.5 Ma (2\u00CF\u0083, including J-error of .16%) MSWD = 1.4, probability=0.23 Includes 95.5% of the 39Ar Plateau steps are filled, rejected steps are open box heights are 2\u00CF\u0083 \u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A0B6\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0Step\u00E2\u0080\u0090heating\u00C2\u00A0cumulative\u00C2\u00A0percent\u00C2\u00A0of\u00C2\u00A039Ar\u00C2\u00A0released\u00C2\u00A0vs.\u00C2\u00A0age\u00C2\u00A0plot\u00C2\u00A0for\u00C2\u00A0sample\u00C2\u00A0LW\u00E2\u0080\u009085\u00C2\u00A0 (hornblende\u00C2\u00A0granite).\u00C2\u00A0 \u00C2\u00A0 0 20 40 60 80 100 120 0 20 40 60 80 100 Cumulative 39Ar Percent A ge (M a) Plateau age = 74.9 \u00C2\u00B1 3.3 Ma (2\u00CF\u0083, including J-error of .16%) MSWD = 1.4, probability=0.18 Includes 97.3% of the 39Ar Plateau steps are filled, rejected steps are open box heights are 2\u00CF\u0083 \u00C2\u00A0 \u00C2\u00A0 Figure\u00C2\u00A0B7\u00C2\u00A0\u00E2\u0080\u0090\u00C2\u00A0Step\u00E2\u0080\u0090heating\u00C2\u00A0cumulative\u00C2\u00A0percent\u00C2\u00A0of\u00C2\u00A039Ar\u00C2\u00A0released\u00C2\u00A0vs.\u00C2\u00A0age\u00C2\u00A0plot\u00C2\u00A0for\u00C2\u00A0sample\u00C2\u00A0LW\u00E2\u0080\u009061\u00C2\u00A0 (hornblende\u00E2\u0080\u0090plagioclase\u00C2\u00A0porphyritic\u00C2\u00A0dyke).\u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0B\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 page\u00C2\u00A0235\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0Appendix\u00C2\u00A0B\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 page\u00C2\u00A0236\u00C2\u00A0\u00C2\u00A0 B.3\u00C2\u00A0 References\u00C2\u00A0 Renne,\u00C2\u00A0P.R.,\u00C2\u00A0Swisher,\u00C2\u00A0C.C.,\u00C2\u00A0III,\u00C2\u00A0Deino,\u00C2\u00A0A.L.,\u00C2\u00A0Karner,\u00C2\u00A0D.B.,\u00C2\u00A0Owens,\u00C2\u00A0T.\u00C2\u00A0and\u00C2\u00A0DePaolo,\u00C2\u00A0D.J.\u00C2\u00A0\u00C2\u00A01998.\u00C2\u00A0\u00C2\u00A0 Intercalibration\u00C2\u00A0of\u00C2\u00A0standards,\u00C2\u00A0absolute\u00C2\u00A0ages\u00C2\u00A0and\u00C2\u00A0uncertainties\u00C2\u00A0in\u00C2\u00A040Ar/39Ar\u00C2\u00A0dating.\u00C2\u00A0\u00C2\u00A0 Chemical\u00C2\u00A0Geology,\u00C2\u00A0145:\u00C2\u00A0117\u00E2\u0080\u0090152.\u00C2\u00A0 Sandeman,\u00C2\u00A0H.A.,\u00C2\u00A0Archibald,\u00C2\u00A0D.A.,\u00C2\u00A0Grant,\u00C2\u00A0J.W.,\u00C2\u00A0Villeneuve,\u00C2\u00A0M.E.,\u00C2\u00A0Ford,\u00C2\u00A0F.D.\u00C2\u00A0\u00C2\u00A02000.\u00C2\u00A0\u00C2\u00A0 Characterization\u00C2\u00A0of\u00C2\u00A0the\u00C2\u00A0chemical\u00C2\u00A0composition\u00C2\u00A0and\u00C2\u00A0(super\u00C2\u00A040)\u00C2\u00A0Ar\u00E2\u0080\u0090\u00C2\u00A0(super\u00C2\u00A039)\u00C2\u00A0Ar\u00C2\u00A0systematics\u00C2\u00A0 of\u00C2\u00A0intralaboratory\u00C2\u00A0standard\u00C2\u00A0MAC\u00E2\u0080\u009083\u00C2\u00A0biotite.\u00C2\u00A0\u00C2\u00A0Current\u00C2\u00A0Research,\u00C2\u00A0Geological\u00C2\u00A0Survey\u00C2\u00A0of\u00C2\u00A0 Canada,\u00C2\u00A0Report:\u00C2\u00A01999\u00E2\u0080\u0090F,\u00C2\u00A0pp.13\u00E2\u0080\u009026.\u00C2\u00A0 \u00C2\u00A0Appendix\u00C2\u00A0C.\u00C2\u00A0\u00C2\u00A0Lithogeochemistry\u00C2\u00A0 ck\u00C2\u00A0analyses\u00C2\u00A0were\u00C2\u00A0performed\u00C2\u00A0from\u00C2\u00A0samples\u00C2\u00A0of\u00C2\u00A0volcanic\u00C2\u00A0 and Sam sits\u00C2\u00A0were\u00C2\u00A0collected\u00C2\u00A0mostly\u00C2\u00A0from\u00C2\u00A0core\u00C2\u00A0in\u00C2\u00A02000\u00C2\u00A0and\u00C2\u00A0were\u00C2\u00A0 analyzed\u00C2\u00A0at\u00C2\u00A0Bondar\u00E2\u0080\u0090Clegg\u00C2\u00A0Laboratories\u00C2\u00A0(now\u00C2\u00A0ALS\u00C2\u00A0Chemex)\u00C2\u00A0in\u00C2\u00A0Vancouver,\u00C2\u00A0Canada\u00C2\u00A0using\u00C2\u00A0 inductively\u00C2\u00A0coupled\u00C2\u00A0plasma\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A0atomic\u00C2\u00A0emission\u00C2\u00A0spectrometry\u00C2\u00A0(ICP\u00E2\u0080\u0090AES)\u00C2\u00A0and\u00C2\u00A0subsequently\u00C2\u00A0for\u00C2\u00A0 additional\u00C2\u00A0trace\u00C2\u00A0elements\u00C2\u00A0(including\u00C2\u00A0rare\u00C2\u00A0earth\u00C2\u00A0elements)\u00C2\u00A0using\u00C2\u00A0inductively\u00C2\u00A0coupled\u00C2\u00A0plasma\u00C2\u00A0\u00E2\u0080\u0093\u00C2\u00A0 mass\u00C2\u00A0spectrometry\u00C2\u00A0(ICP\u00E2\u0080\u0090MS)\u00C2\u00A0at\u00C2\u00A0Memorial\u00C2\u00A0University,\u00C2\u00A0St.\u00C2\u00A0John\u00E2\u0080\u0099s,\u00C2\u00A0Canada\u00C2\u00A0(Table\u00C2\u00A0C1).\u00C2\u00A0\u00C2\u00A0Regional\u00C2\u00A0 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andesite;\u00C2\u00A0B\u00C2\u00A0=\u00C2\u00A0basalt;\u00C2\u00A0R\u00C2\u00A0=\u00C2\u00A0rhyolite;\u00C2\u00A0RD\u00C2\u00A0=\u00C2\u00A0rhyolite\u00C2\u00A0dyke\u00C2\u00A0(post\u00C2\u00A0mineralization);\u00C2\u00A0bx\u00C2\u00A0=\u00C2\u00A0breccia.\u00C2\u00A0 le\u00C2\u00A0C1.\u00C2\u00A0\u00C2\u00A0Whole\u00C2\u00A0rock\u00C2\u00A0geochemical\u00C2\u00A0analyses.\u00C2\u00A0\u00C2\u00A0Major\u00C2\u00A0oxides\u00C2\u00A0are\u00C2\u00A0from\u00C2\u00A0Bondar\u00E2\u0080\u0090Clegg\u00C2\u00A0Laborato Formation;\u00C2\u00A0CEEF\u00C2\u00A0=\u00C2\u00A0Cerro\u00C2\u00A0El\u00C2\u00A0Ereo\u00C2\u00A0Formation;\u00C2\u00A0LBF\u00C2\u00A0=\u00C2\u00A0La\u00C2\u00A0Bocana\u00C2\u00A0Formation.\u00C2\u00A0\u00C2\u00A0D\u00C2\u00A0=\u00C2\u00A0dacite;\u00C2\u00A0A\u00C2\u00A0=\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Page\u00C2\u00A0239\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0C1.\u00C2\u00A0\u00C2\u00A0(Cont)\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Page\u00C2\u00A0240\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0C1.\u00C2\u00A0\u00C2\u00A0(Cont)\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Page\u00C2\u00A0241\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0C1.\u00C2\u00A0\u00C2\u00A0(Cont)\u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Page\u00C2\u00A0242\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0C1.\u00C2\u00A0\u00C2\u00A0(Cont)\u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Page\u00C2\u00A0243\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0C1.\u00C2\u00A0\u00C2\u00A0(Cont)\u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Page\u00C2\u00A0244\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0C1.\u00C2\u00A0\u00C2\u00A0(Cont)\u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Page\u00C2\u00A0245\u00C2\u00A0 \u00C2\u00A0Tab \u00C2\u00A0geochemical\u00C2\u00A0analyses.\u00C2\u00A0\u00C2\u00A0Major\u00C2\u00A0oxides\u00C2\u00A0are\u00C2\u00A0from\u00C2\u00A0Bondar\u00E2\u0080\u0090Clegg\u00C2\u00A0Laboratories.\u00C2\u00A0\u00C2\u00A0 Trace\u00C2\u00A0elements\u00C2\u00A0are\u00C2\u00A0from\u00C2\u00A0Memorial\u00C2\u00A0University.\u00C2\u00A0 le\u00C2\u00A0C2.\u00C2\u00A0\u00C2\u00A0Whole\u00C2\u00A0rock \u00C2\u00A0 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Page\u00C2\u00A0246\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0C2.\u00C2\u00A0(cont)\u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Page\u00C2\u00A0247\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0C2.\u00C2\u00A0(cont)\u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Page\u00C2\u00A0248\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0C2.\u00C2\u00A0(cont)\u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Page\u00C2\u00A0249\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0C2.\u00C2\u00A0(cont)\u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Page\u00C2\u00A0250\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0C2.\u00C2\u00A0(cont)\u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Page\u00C2\u00A0251\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0C2.\u00C2\u00A0(cont)\u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Page\u00C2\u00A0252\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0C2.\u00C2\u00A0(cont)\u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Page\u00C2\u00A0253\u00C2\u00A0 \u00C2\u00A0Table\u00C2\u00A0C2.\u00C2\u00A0(cont)\u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Page\u00C2\u00A0254\u00C2\u00A0 \u00C2\u00A0Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Page\u00C2\u00A0255\u00C2\u00A0 Table\u00C2\u00A0C2.\u00C2\u00A0(cont)\u00C2\u00A0 \u00C2\u00A0Page\u00C2\u00A0256\u00C2\u00A0 Table\u00C2\u00A0C3.\u00C2\u00A0\u00C2\u00A0Memorial\u00C2\u00A0University\u00C2\u00A0analyses\u00C2\u00A0of\u00C2\u00A0in\u00E2\u0080\u0090house\u00C2\u00A0standards\u00C2\u00A0run\u00C2\u00A0with\u00C2\u00A0samples\u00C2\u00A0from\u00C2\u00A0this\u00C2\u00A0study.\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Sample Y Zr Nb Ba La Ce Pr Nd Sm Eu Gd 157 MRG-1(MUN run 78-108) 11.5 107 22.3 49.4 8.83 25.8 3.71 17.6 4.34 1.38 BR-688 (MUN run 161-191 17.81 59.15 4.87 163.33 4.98 11.55 1.65 8.03 2.3 0.94 MRG-AVG 9.9912991 113.71705 25.255068 44.090476 7.678709 21.623305 3.1389724 15.492122 4.2540543 1.3832493 BRG-AVG 16.617819 64.413971 5.6533517 160.0276 4.7409816 10.870648 1.5547568 7.6410572 2.3681281 1.0108726 Limit of Detection 0.0092306 0.0628715 0.0238228 0.1546975 0.0076891 0.0057409 0.0065007 0.0302344 0.0189688 0.0055531 0.0178039 BLANK-25 1.9430877 1.4203941 0.0493796 1.8309588 0.4939528 0.135662 0.0931578 0.0151615 0.0030624 BLANK-26 2.3479125 1.2090626 0.007367 1.8103243 0.6192861 0.1073477 0.1291485 0.0122866 BLANK-27 2.424286 0.8357417 0.0299783 2.0968618 0.6481933 0.1368853 0.1210043 0.0110069 BLANK-28 1.9764842 0.8066353 0.0033698 1.6830069 0.5683987 0.1494276 0.1208334 BR-688-27 17.697234 67.612528 6.071878 175.38593 5.1200486 11.651453 1.6719865 8.168316 2.479277 1.0672273 #N/A BR-688-25 15.538405 61.215414 5.2348254 144.66928 4.3619146 10.089843 1.4375272 7.1137983 2.2569791 0.954518 #N/A MRG-1-25 9.7308945 112.67704 25.065669 42.10709 7.4229731 21.054179 3.0390699 15.046007 4.185491 1.3668896 #N/A MRG-1-27 10.251704 114.75705 25.444467 46.073862 7.9344449 22.192431 3.2388748 15.938237 4.3226176 1.3996091 #N/A Sample Gd 160 Tb Dy Ho Er Tm Yb Lu Hf Ta Th MRG-1(MUN run 78-108) 3.97 0.52 3 0.49 1.16 0.14 0.79 0.11 3.89 0.74 0.82 BR-688 (MUN run 161-191 2.88 0.48 3.21 0.7 2.1 0.3 2 0.3 1.54 0.18 0.33 MRG-AVG 3.8189632 0.5027635 2.7189793 0.466624 1.1822944 0.1327873 0.7418058 0.1039626 4.8753173 0.3638535 0.6921084 BRG-AVG 2.9389857 0.485098 3.268199 0.7128201 2.2701266 0.3059436 1.9527507 0.318213 2.1618878 0.1723741 0.3225851 Limit of Detection 0.0104266 0.0039823 0.015266 0.0029849 0.0136461 0.0054858 0.0154391 0.0023617 0.0174635 0.0154686 0.0038651 BLANK-25 0.009143 0.0992321 0.0027314 0.0084104 0.0030661 0.000543 0.1602147 0.005113 0.5111245 0.003583 0.0288197 BLANK-26 0.009946 0.1484815 0.0077109 0.2101635 0.0081732 0.4856024 0.0028297 0.0224256 BLANK-27 0.0101534 0.2162612 0.0018642 0.0081206 0.1912325 0.0066691 0.4225627 0.0015785 0.0186191 BLANK-28 0.0103336 0.1376261 0.0011799 0.0083888 0.3672724 0.0091971 0.4107917 0.002473 0.0213467 BR-688-27 3.1231084 0.5225309 3.5320501 0.7495594 2.3861954 0.3243691 2.0867531 0.3387535 2.2301692 0.1580354 0.3493235 BR-688-25 2.754863 0.447665 3.0043479 0.6760809 2.1540577 0.2875182 1.8187484 0.2976726 2.0936064 0.1867129 0.2958467 MRG-1-25 3.7526247 0.4878681 2.6569843 0.4629034 1.1875442 0.1324349 0.7319475 0.1028635 4.8652768 0.4407932 0.6503028 MRG-1-27 3.8853017 0.5176589 2.7809743 0.4703446 1.1770445 0.1331398 0.7516642 0.1050616 4.8853579 0.2869139 0.7339139 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0Table\u00C2\u00A0C4.\u00C2\u00A0\u00C2\u00A0ALS\u00C2\u00A0Chemex\u00C2\u00A0analyses\u00C2\u00A0of\u00C2\u00A0MDRU\u00C2\u00A0standards\u00C2\u00A0run\u00C2\u00A0with\u00C2\u00A0samples\u00C2\u00A0from\u00C2\u00A0this\u00C2\u00A0study.\u00C2\u00A0 \u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 SAMPLE Al2O3 BaO CaO Cr2O3 Fe2O3 K2O MgO MnO Na2O P2O5 SiO2 SrO TiO2 LOI TOTAL Ag Ba Ce Co Cr Cs Cu Dy Er Eu Ga BAS1 15.36 0.02 8.14 0.03 10.83 0.53 7.19 0.13 3.28 0.26 52.75 0.05 1.22 -0.17 99.62 <1 180.0 21.0 51.5 260 0.1 275 2.9 1.5 1.2 20 BAS1 15.52 0.02 8.1 0.03 10.76 0.54 7.14 0.13 3.3 0.24 52.98 0.05 1.23 -0.11 99.93 <1 187.0 20.5 44.0 230 0.1 155 2.8 1.4 1.1 20 BAS1 15.61 0.02 8.1 0.03 10.85 0.55 7.19 0.14 3.36 0.15 53.34 0.05 1.24 -0.27 100.35 <1 184.5 22.0 43.0 180 0.1 45 3.1 1.6 1.1 18 BAS1 Average (n=3) 15.50 0.02 8.11 0.03 10.81 0.54 7.17 0.13 3.31 0.22 53.02 0.05 1.23 -0.18 99.97 183.8 21.2 46.2 223 0.1 158 2.9 1.5 1.1 19 BAS-1 (Piercey, 2001) 15.12 8.28 11.16 0.56 7.35 0.14 3.28 0.22 53.56 1.31 0.78 100.96 0.28 194 21.8 42.2 226.6 0.12 59.6 3.26 1.54 1.28 19.6 P-1 14.32 0.09 3.51 0.01 3.77 2.03 1.01 0.07 3.8 0.1 70.12 0.02 0.35 0.59 99.79 <1 822 25 7.5 160 1.2 15 2.9 1.9 0.7 15 P-1 14.39 0.09 3.38 0.01 3.77 2.08 1.02 0.07 3.89 0.13 70.3 0.02 0.35 0.33 99.83 <1 798 25 8.5 180 1.3 15 3 2.1 0.8 15 P-1 14.37 0.09 3.54 0.01 3.75 2.05 1.02 0.07 3.85 0.07 70.41 0.02 0.35 0.38 99.98 P-1 Average (n=3) 14.36 0.09 3.48 0.01 3.76 2.05 1.02 0.07 3.85 0.10 70.28 0.02 0.35 0.43 99.87 810 25 8 170 1.25 15 2.95 2 0.75 15 P-1 (Piercey, 2001) 14.1 3.49 3.9 2.12 1.11 0.08 3.8 0.08 70.96 0.38 0.72 100.56 0.3 724 28 6.2 149.2 1.22 15.5 3.34 2.1 0.78 15 LOD 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 1 0.5 0.5 0.5 10 0.1 5 0.1 0.1 0.1 1 SAMPLE Gd Hf Ho La Lu Mo Nb Nd Ni Pb Pr Rb Sm Sn Sr Ta Tb Th Tl Tm U V W Y Yb Zn Zr BAS1 3.4 2 0.6 8.5 0.2 8 8 13.0 190 20 2.9 7.6 3.4 1 483 0.5 0.5 1 <0.5 0.2 <0.5 200 2 15.5 1.4 120 84.5 BAS1 3.3 2 0.6 8.5 0.1 8 7 13.5 175 5 2.9 7 3.4 1 490 <0.5 0.5 1 <0.5 0.2 <0.5 190 2 15 1.3 105 80 BAS1 3.4 2 0.6 11.0 0.1 6 7 13.0 160 5 2.8 7.4 3.1 1 404 0.5 0.5 <1 <0.5 0.2 <0.5 165 2 16 1.2 110 79.5 BAS1 Average (n=3) 3.4 2 0.6 9.3 0.1 7 7 13.2 175 10 2.9 7.3 3.3 1 459 0.5 0.5 1 0.2 185 2 15.5 1.3 112 81 BAS-1 (Piercey, 2001) 3.8 2.36 0.61 9.28 0.21 2.24 8.2 13.6 172 4.4 3 6.96 3.5 1.2 502 0.45 0.57 0.84 0.06 0.23 0.32 152 18.4 1.4 91.4 94.5 P-1 2.7 4 0.7 11.5 0.4 6 4 12.5 5 5 3.1 51.4 2.9 3 247 <0.5 0.5 5 <0.5 0.4 1.5 70 4 19.5 2.3 50 131.5 P-1 3.1 4 0.7 11.5 0.4 6 5 12.5 10 15 3.2 52.4 2.9 2 244 0.5 0.5 5 <0.5 0.3 2 85 2 20.5 2.3 50 142.5 P-1 P-1 Average (n=3) 2.9 4 0.7 11.5 0.4 6 4.5 12.5 7.5 10 3.15 51.9 2.9 2.5 245.5 0.5 0.5 5 0.35 1.75 77.5 3 20 2.3 50 137 P-1 (Piercey, 2001) 3.12 3.76 0.72 13.2 0.4 0.52 3.78 13 10.2 3.36 50.4 2.92 2.44 256 0.3 0.52 4.38 0.31 0.35 1.48 58.2 22.8 2.46 44 126 LOD 0.1 1 0.1 0.5 0.1 2 1 0.5 5 5 0.1 0.2 0.1 1 0.1 0.5 0.1 1 0.5 0.1 0.5 5 1 0.5 0.1 5 0.5 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 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Figure\u00C2\u00A0C8.\u00C2\u00A0(following\u00C2\u00A0page).\u00C2\u00A0\u00C2\u00A0Primitive\u00C2\u00A0mantle\u00E2\u0080\u0090normalized\u00C2\u00A0trace\u00C2\u00A0element\u00C2\u00A0diagrams\u00C2\u00A0for\u00C2\u00A0repeat\u00C2\u00A0analyses\u00C2\u00A0of\u00C2\u00A0in\u00E2\u0080\u0090house\u00C2\u00A0and\u00C2\u00A0internal\u00C2\u00A0reference\u00C2\u00A0 material\u00C2\u00A0conducted\u00C2\u00A0during\u00C2\u00A0this\u00C2\u00A0study.\u00C2\u00A0\u00C2\u00A0A.\u00C2\u00A0\u00C2\u00A0ICP\u00E2\u0080\u0090MS\u00C2\u00A0data\u00C2\u00A0(Memorial\u00C2\u00A0Univ.)\u00C2\u00A0for\u00C2\u00A0standards\u00C2\u00A0MRG\u00E2\u0080\u00901\u00C2\u00A0and\u00C2\u00A0BR\u00E2\u0080\u0090688\u00C2\u00A0compared\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0detection\u00C2\u00A0limit.\u00C2\u00A0\u00C2\u00A0 B.\u00C2\u00A0\u00C2\u00A0Average\u00C2\u00A0analyses\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0reference\u00C2\u00A0materials\u00C2\u00A0from\u00C2\u00A0this\u00C2\u00A0study\u00C2\u00A0in\u00C2\u00A0(A)\u00C2\u00A0compared\u00C2\u00A0to\u00C2\u00A0given\u00C2\u00A0values\u00C2\u00A0from\u00C2\u00A0previous\u00C2\u00A0analysis\u00C2\u00A0by\u00C2\u00A0Memorial\u00C2\u00A0Univ.\u00C2\u00A0of\u00C2\u00A0 the\u00C2\u00A0material.\u00C2\u00A0C.\u00C2\u00A0\u00C2\u00A0ICP\u00E2\u0080\u0090AES\u00C2\u00A0data\u00C2\u00A0(ALS\u00C2\u00A0Chemex)\u00C2\u00A0for\u00C2\u00A0MDRU\u00C2\u00A0reference\u00C2\u00A0samples\u00C2\u00A0BAS\u00E2\u0080\u00901\u00C2\u00A0and\u00C2\u00A0P\u00E2\u0080\u00901\u00C2\u00A0as\u00C2\u00A0compared\u00C2\u00A0to\u00C2\u00A0the\u00C2\u00A0detection\u00C2\u00A0limit\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0 technique.\u00C2\u00A0\u00C2\u00A0D.\u00C2\u00A0\u00C2\u00A0Average\u00C2\u00A0values\u00C2\u00A0for\u00C2\u00A0the\u00C2\u00A0reference\u00C2\u00A0materials\u00C2\u00A0from\u00C2\u00A0this\u00C2\u00A0study\u00C2\u00A0from\u00C2\u00A0in\u00C2\u00A0(C)\u00C2\u00A0compared\u00C2\u00A0to\u00C2\u00A0data\u00C2\u00A0from\u00C2\u00A0Piercey\u00C2\u00A0(2001).\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 \u00C2\u00A0 Page\u00C2\u00A0259\u00C2\u00A0 \u00C2\u00A0C.2\u00C2\u00A0 References\u00C2\u00A0 Longerich,\u00C2\u00A0H.P.,\u00C2\u00A0Jenner,\u00C2\u00A0G.A.,\u00C2\u00A0Fryer,\u00C2\u00A0B.J.\u00C2\u00A0and\u00C2\u00A0Jackson,\u00C2\u00A0S.E.,\u00C2\u00A01990.\u00C2\u00A0Inductively\u00C2\u00A0coupled\u00C2\u00A0plasma\u00E2\u0080\u0090 mass\u00C2\u00A0spectrometric\u00C2\u00A0analysis\u00C2\u00A0of\u00C2\u00A0geological\u00C2\u00A0samples:\u00C2\u00A0an\u00C2\u00A0overview.\u00C2\u00A0Chemical\u00C2\u00A0Geology\u00C2\u00A083:\u00C2\u00A0105\u00E2\u0080\u0090 118.\u00C2\u00A0 \u00C2\u00A0 Piercey,\u00C2\u00A0S.J.\u00C2\u00A0\u00C2\u00A02001.\u00C2\u00A0\u00C2\u00A0Petrology\u00C2\u00A0and\u00C2\u00A0tectonic\u00C2\u00A0setting\u00C2\u00A0of\u00C2\u00A0felsic\u00C2\u00A0and\u00C2\u00A0mafic\u00C2\u00A0volcanic\u00C2\u00A0and\u00C2\u00A0intrusive\u00C2\u00A0 rocks\u00C2\u00A0in\u00C2\u00A0the\u00C2\u00A0Finlayson\u00C2\u00A0Lake\u00C2\u00A0volcanic\u00E2\u0080\u0090hosted\u00C2\u00A0massive\u00C2\u00A0sulphide\u00C2\u00A0(VHMS)\u00C2\u00A0district,\u00C2\u00A0Yukon\u00C2\u00A0 Canada:\u00C2\u00A0A\u00C2\u00A0record\u00C2\u00A0of\u00C2\u00A0mid\u00E2\u0080\u0090Paleozoic\u00C2\u00A0arc\u00C2\u00A0and\u00C2\u00A0back\u00E2\u0080\u0090arc\u00C2\u00A0magmatism\u00C2\u00A0and\u00C2\u00A0metallogeny.\u00C2\u00A0 Unpublished\u00C2\u00A0Ph.D.\u00C2\u00A0thesis,\u00C2\u00A0The\u00C2\u00A0University\u00C2\u00A0of\u00C2\u00A0British\u00C2\u00A0Columbia,\u00C2\u00A0304\u00C2\u00A0p.\u00C2\u00A0 \u00C2\u00A0 Appendix\u00C2\u00A0C\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0\u00C2\u00A0 Page\u00C2\u00A0260\u00C2\u00A0"@en . "Thesis/Dissertation"@en . "2008-11"@en . "10.14288/1.0052903"@en . "eng"@en . "Geological Sciences"@en . "Vancouver : University of British Columbia Library"@en . "University of British Columbia"@en . "Attribution-NonCommercial-NoDerivatives 4.0 International"@en . "http://creativecommons.org/licenses/by-nc-nd/4.0/"@en . "Graduate"@en . "The genesis of \u00E2\u0080\u0098giant\u00E2\u0080\u0099 copper-zinc-gold-silver volcanogenic massive sulphide deposits at Tambogrande, Per\u00C3\u00BA : age, tectonic setting, paleomorphology, lithogeochemistry, and radiogenic isotopes"@en . "Text"@en . "http://hdl.handle.net/2429/773"@en .