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The geology, alteration and timing of porphyry intrusions and breccias associated with the development… Guitart, Agustin 2020

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iThe geology, alteration and  timing of porphyry intrusions and breccias associated with the development of Los Helados porphyry copper-gold deposit, ChilebyAgustin Guitart B.Sc.,Universidad de Buenos Aires, 2007 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OFTHE REQUIREMENTS FOR THE DEGREE OFMASTER OF SCIENCEinTHE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES(Geological Sciences)THE UNIVERSITY OF BRITISH COLUMBIA(Vancouver)July 2020© Agustin Guitart, 2020iiThe following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the thesis entitled:The geology, alteration and timing of porphyry intrusions and breccias associated with the development of Los Helados porphyry copper-gold deposit, Chile.submitted by                  Agustin Guitart             in partial fulfillment of the requirements for the degree of Master of Science                                                                                                    in Geological Sciences                                                                                                             Examining Committee:Dr Craig Hart, Director MDRU, Geological Sciences, UBC.                                                           Supervisor Dr Kelly Russell, Professor, Volcanology & Petrology Laboratory, UBC.                                       Supervisory Committee Member Dr Thomas Bissig  ,  MDRU reserch associate, UBC.                                                                                                                             Supervisory Committee MemberDr Sean Crowe, Associate professor, Department of Earth, Ocean and Atmospheric Sciences, UBCAdditional Examiner iiiAbstractThe Los Helados porphyry Cu-Au deposit is part of the Miocene belt of northern Chile, it is located at -28.34 Lat and -69.58 Long, between the Maricunga and El Indio metallogenic belts.Multiple intrusion and brecciation events occurred during the late Miocene in the Los Helados that gave rise to the current distribution of hydrothermal alteration assemblages and associated sulfide mineralization. The Miocene magmatic-hydrothermal history is divided in 6 stages grouped in pre-mineralization stage 1 (Quartz Feldspar Porphyry), inter-mineralization stages 2-3-4-5 (Fine Grained Plagioclase Crowded Porphyry, Matrix Rich Breccia, Cement Rich Breccia, Bimodal Plagioclase Porphyry) of which stages 3 and 4 are the main mineralizing events, and late- mineralization stage 6 (Biotite Plagioclase Porphyry).Based on U-Pb zircon ages, the duration of the magmatic processes is estimated between 13.97+/- 0.1 Ma (the age obtained for the precursor Quartz Feldspar Porphyry) and 13.75+/-0.13 (the age obtained for the youngest porphyry, the Biotite Plagioclase Porphyry). This estimation gives a minimum duration of 0.22 +/- 0.16 Ma for the magmatic processes at Los Helados.White micas are a common alteration component in all alteration assemblages at Los Helados, and changes in the chemistry of those micas can be detected using short-wave infrared spectra (SWIR). The economic ore metal (Cu, Au, Ag) at Los Helados is associated with the phengite composition indicating the copper deposition in less acidic conditions.Los Helados is located in a zone with a complex tectonic segmentation. On the one hand, it is situated near the present-day northern limit of the Chilean-Pampean flat-slab segment of the central Andes. On the other hand, translithospheric faults that can be traced from the Pacific coast of Chile, across the Cordillera Occidental, and into the Puna play an important role in the segmentation of the Andes at this latitude. As a result of this segmentation, Los Helados shows differences in terms of host rock, style of mineralization, depth of emplacement and alteration that distinguished it from the classic Au (Cu) porphyry deposits of the Maricunga metallogenetic belt.ivLay summaryPorphyry copper deposits play an important role in copper mining .  The discovery of new  deposits through exploration is essential to sustain the growing demand of the modern market; however, in recent decades, these discoveries have been sporadic. In this regard, the discovery of the Los Helados porphyry Cu-Au deposit is one of the most important of the last decade in northern Chile.This thesis unravels the sequence of Miocene porphyry intrusion and breccias that produced the current distribution of alteration and mineralization at Los Helados. This is supported by thorough documentation of lithology, alteration, and laboratory techniques including petrography, geochronology, whole-rock geochemistry, short-wave infrared spectroscopy, and X-ray diffraction methods.On a regional scale, the understanding of the geological features at Los Helados allows comparing with the adjacent metallogenic belts. This thesis concludes that the differences observed between deposits are due to changes in host-rocks and different emplacement depths.  vPrefaceThis work was supported by NGex Resources. The work is the result of the author´s work from September 2014 to September 2016. This thesis was done by the author, under the collaborative supervision of the committee members Craig Hart, Thomas Bissig, and Kelly Russell.The author is responsible for all descriptive data collected from detailed drill core logs and for sample selection intended for several analytical methods, including petrography, geochronology, short-wave infrared spectroscopy (SWIR), X-Ray Diffraction (XRD), and geochemistry.SWIR and XRD data collection and interpretation as well as petrographic descriptions were done by the author at UBC facilities.All radiometric age dating process was performed by Pacific Centre for Isotopic and Geochemical Research (PCIGR) of the Earth, Ocean and Atmospheric Sciences (EOAS), of The University of British Columbia.viTable of contentsAbstract .........................................................................................................................................iiiLay summary..................................................................................................................................ivPreface.............................................................................................................................................vTable of contents.............................................................................................................................viList of tables..................................................................................................................................xii List of figures................................................................................................................................xviList of abbreviations...................................................................................................................xxxiiChapter 1: Introduction....................................................................................................................1 1.1 Overview........................................................................................................................1 1.2 Objectives of this study..................................................................................................3 1.3 Location and access and climate....................................................................................3 1.4 Metallogenic setting: description of El Indio and Maricunga belts...............................5  1.4.1 The Maricunga belt.........................................................................................5  1.4.2 El Indio belt.....................................................................................................8 1.5 History of exploration..................................................................................................10 1.6 Porphyry copper deposits.............................................................................................10 1.7 Research approach and methodology...........................................................................11vii  1.7.1 Detailed drill logs and mapping....................................................................13  1.7.2 Petrography...................................................................................................13  1.7.3 Whole-rock geochemistry.............................................................................13  1.7.4 Geochronology..............................................................................................13  1.7.5 Short-wave infrared spectroscopy (SWIR)...................................................14  1.7.6 X-ray diffraction (XRD)................................................................................14Chapter 2: Geological framework..................................................................................................15 2.1 Geological setting........................................................................................................15 2.2 Lithology......................................................................................................................19  2.2.1 Late Paleozoic to Triassic basement rocks (Permo-Triassic suite)...............19   2.2.1.1 Granite............................................................................................19   2.2.1.2 Feldspar Phyric Rhyodacites.........................................................20   2.2.1.3 Andesite dikes................................................................................20   2.2.1.4 Gabbro-Diorite...............................................................................20  2.2.2 Miocene porphyry intrusions and breccias....................................................23   2.2.2.1 Quartz Feldspar Porphyry...............................................................25   2.2.2.2 Fine Grained Plagioclase Crowded Porphyry................................26   2.2.2.3 Matrix Rich Breccia.......................................................................28viii   2.2.2.4 Cement Rich Breccia......................................................................30   2.2.2.5 Bimodal Plagioclase Porphyry.......................................................32   2.2.2.6 Biotite Plagioclase Porphyry..........................................................34Chapter 3: Hydrothermal alteration and mineralization.................................................................38 3.1 Overview......................................................................................................................38 3.2 Alteration assemblages at Los Helados porphyry Cu-Au deposit................................43  3.2.1. K-feldspar (Potassic) alteration....................................................................43  3.2.2 Biotite (Potassic) alteration...........................................................................45  3.2.3 Sericite- magnetite -chlorite alteration..........................................................45  3.2.4 Sericite alteration..........................................................................................47  3.2.5 Epidote-chlorite alteration............................................................................47  3.2.6 Pyrophyllite-kaolinite alteration....................................................................47 3.3 Alteration zoning at the Los Helados porphyry Cu-Au deposit...................................48 3.4 White micas at the Los Helados porphyry Cu-Au deposit...........................................49  3.4.1 Short-wave infrared (SWIR) spectroscopy ..................................................49  3.4.2 SWIR spectroscopy results from Los Helados porphyry Cu-Au deposit......50 3.5 Vein paragenesis and timing of hydrothermal mineralization at Los  Helados                porphyry  Cu-Au deposit...................................................................................................54  3.5.1 Vein classification.........................................................................................54   3.5.1.1 Early veins......................................................................................55ix   3.5.1.2 Transitional veins...........................................................................56   3.5.1.3 Late veins.......................................................................................58  3.5.2 Vein and mineralization timing.....................................................................60   3.5.2.1 Veins in late-mineral phases...........................................................60   3.5.2.2 Veins in inter-mineral phases.........................................................62   3.5.2.3 Veins in pre-mineral phases............................................................63 3.6 Sulfide and metal zoning at the Los Helados porphyry Cu-Au deposit.......................63  3.6.1 Sulfide zoning................................................................................................63  3.6.2 Metal zoning.................................................................................................66   3.6.2.1 Copper distribution........................................................................66   3.6.2.2 Gold distribution............................................................................66   3.6.2.3 Silver distribution...........................................................................66   3.6.2.4 Molybdenum distribution..............................................................66Chapter 4: Whole rock geochemistry.............................................................................................69 4.1 Hydrothermal alteration effects...................................................................................69 4.2 Harker variation diagrams............................................................................................71 4.3 Trace element classification.........................................................................................73 4.4 Petrogenetic constraints from REE and trace elements...............................................74x 4.5 Adakite-like signature and porphyry fertility indicators of Miocene rocks.................77Chapter 5: Discussion....................................................................................................................80 5.1 Miocene magmatic and hydrothermal evolution of Los Helados................................80 5.2 Mineralization style......................................................................................................86 5.3 Molybdenite age...........................................................................................................87 5.4 Depth of emplacement.................................................................................................87 5.5 Variation of white mica composition and its relationship with copper            mineralization....................................................................................................................89  5.5.1 White mica crystallinity................................................................................92 5.6  Temperature and pH gradient......................................................................................93 5.7 Metallogenetic context of Los Helados.......................................................................94  5.7.1 El Indio metallogenetic belt and Los Helados..............................................94  5.7.2 Maricunga metallogenetic belt and Los Helados..........................................94 5.8 Regional-scale faults and segmentation of Los Andes.................................................99Chapter 6: Conclusions, exploration implications and future work............................................102 6.1 Conclusions................................................................................................................102  6.1.1 Miocene magmatic and hydrothermal evolution........................................102  6.1.2 Sulfide mineralization.................................................................................103  6.1.3  White micas and pH and copper sulfides...................................................103xi  6.1.4 Metallogenetic context of Los Helados......................................................104 6.2 Exploration implications............................................................................................104 6.3 Future works...............................................................................................................105References....................................................................................................................................107Appendix A: Petrography.............................................................................................................118Appendix B:Whole-rock geochemistry........................................................................................159Appendix C: Geochronology........................................................................................................166Appendix D: Short-Wave Infrared spectroscopy (SWIR)...........................................................176Appendix E: X-Ray Diffraction (XRD).......................................................................................202Appendix F: Drill core logging....................................................................................................216Appendix G: Drill Hole location, azimut, dip and deph.............................................................224xiiList of tablesTable 2.1: Characteristics of the Miocene intrusions in the Los Helados deposit area. Abbreviations: Miocene intrusives: BPP: Biotite Plagioclase Porphyry; BiPP: Bimodal Plagioclase Porphyry; FGPCP; Fine Grained Plagioclase Crowded Porphyry; QFP: Quartz Feldspar Porphyry. Minerals: Anhy: Anhydrite; Bio: biotite; Cpy: chalcopyrite; Cu: copper; Gyp: gypsum; Qz: quartz; Mg: magnetite; Plag: plagioclase; Ser: sericite................................Table 2.2: Characteristics of the Miocene hydrothermal breccias in the Los Helados area. Abbreviations: MRBX: Matrix Rich Breccia; CBX: Cement Rich Breccia; GRN: Granite, FPR: Feldspar Phyric Rhyodacites, AND: Andesites, GA/DIO:Gabbro-Diorite ......................Table 3.1: Hydrothermal alteration mineral assemblages documented at Los Helados. Abbreviations: Al: Albite; Anhy: Anhydrite; Bio: biotite; Cpy: chalcopyrite; Chl; chlorite; Dik: dickite; Epi: epidote; Gyp: gypsum; Ill: illite; Kao: kaolinite; Kfs: potassic feldspar; Qz: quartz; Mg: magnetite; Mo: molybdenite; Musc; muscovite; Plag: plagioclase; Py: pyrite; Pyr: pyrophyllite; Tour: tourmaline..........................................................................................Table 3.2: Main absorption features present in phyllosilicates and clays..................................Table 3.3: The characteristic features for white mica, clay, and chlorite minerals common to this study and the approximate position of their Al-OH absorption (Thompson et al., 1999)....Table 3.4: Alteration assemblages, white micas documented and the range of the values of the 2200 absorption feature..............................................................................................................Table 4.1: Summary of Petrogenetic Indicators for Crustal Magma Differentiation Depth/Pressure and Adakite-Like Features. Abbreviations: GRN: Granite, FPR: Feldspar Phyric Rhyodacites, AND: Andesites, GA/DIO: Gabbro- Diorite, BPP: Biotite Plagioclase Porphyry; BiPP: Bimodal Plagioclase Porphyry; FGPCP; Fine Grained Plagioclase Crowded Porphyry; QFP: Quartz Feldspar Porphyry.................................................................................................Table 5.1: The characteristics of the Al-OH absorption feature for white micas (Modified from Thompson et al., 1999)...............................................................................................................2424435051527589xiiiTable 5.2: White micas crystallinity values determined by the Kubler Index (KI) for drill holes LHDH 20 and LHDH24. The Kübler Index is negatively correlated with crystallinity. The more crystalline minerals yield lower values. ....................................................................Table 5.3: Characteristics of deposits from Maricunga, El Indio belt and Los Helados area.....Table 5.4: Characteristics of the veins present in the Maricunga metallogenic belt...................Table A1:  Location for petrography  samples...........................................................................Table A2: Description of the sample AG0001...........................................................................Table A3: Description of the sample AG0003........................................................................Table A4: Description of the sample AG0002...........................................................................Table A5: Description of the sample AG0004...........................................................................Table A6: Description of the sample AG0005............................................................................Table A7: Description of the sample AG0006..........................................................................Table A8: Description of the sample AG0007...........................................................................Table A9: Description of the sample AG0008...........................................................................Table A10: Description of the sample AG0009.........................................................................Table A11: Description of the sample AG0010..........................................................................Table A12: Description of the sample AG0011...........................................................................Table A13: Description of the sample AG0012....................................................................9396  99119120121122123124125126127128129130131xivTable A14: Description of the sample AG0013....................................................................Table A15: Description of the sample AG0014....................................................................Table A16: Description of the sample AG0015....................................................................Table A17: Description of the sample AG0016....................................................................Table A18: Description of the sample AG0018....................................................................Table A19: Description of the sample AG0019....................................................................Table A20: Description of the sample AG0020....................................................................Table A21: Description of the sample AG0021....................................................................Table A22: Description of the sample AG0022....................................................................Table A23: Description of the sample AG0023....................................................................Table A24: Description of the sample AG0024 and AG0025...............................................Table A25: Description of the sample AG0026....................................................................Table A26: Description of the sample AG0027....................................................................Table A27: Description of the sample AG0028....................................................................Table A28: Description of the sample AG0029....................................................................Table A29: Description of the sample AG200....................................................................Table A30: Description of the sample AG201........................................................................132133134135136137138139140141142143144145146147148xvTable A31: Description of the sample AG202........................................................................Table A32: Description of the sample AG203........................................................................Table A33: Description of the sample AG204........................................................................Table A34: Description of the sample AG205........................................................................Table A35: Description of the sample AG206.......................................................................Table A36: Description of the sample AG207.......................................................................Table A37: Description of the sample AG208........................................................................Table A38: Description of the sample AG210........................................................................Table A39: Description of the sample AG211........................................................................Table A40: Description of the sample 217.............................................................................Table B1:  Location for geochemical samples.......................................................................Table B2:  Geochemistry results.............................................................................................Table C1: Location for U/Pb geochronology samples...............................................................Table C2: U/PB geochronology data......................................................................................Table D1: Location for SWIR samples..................................................................................Table E1: Comparison between SWIR and XRD data. ..........................................................Table G1:  Drill hole location, altitude, azimuth, dip and depth..............................................149150151152153154155156157158160162168169178203217xviList of figuresFigure 1.1: Location of Los Helados with respect to other well-known deposits from northern Chile within the El Indio and Maricunga metallogenic belts. Modified from Cahill and Isacks (1992).......................................................................................................................................Figure 1.2: Generalized geology of the Maricunga belt (modified from Vila and Sillitoe, 1991 and Maksaev et al., 2014). Both Western (24 – 20 Ma) and Eastern (14 – 13 Ma) Sub-belts are also indicated............................................................................................................................Figure 1.3: Regional simplified geology of the El Indio-Pascua belt and location of mined deposits and major prospects (modified from Bissig et al., 2015)............................................Figure 1.4: Worldwide locations of porphyry Cu systems cited as examples of features discussed in the text along with five additional giant examples. The principal deposit type(s), contained metals, and age are also indicated (modified after Sillitoe, 2010)............................Figure 2.1: Lithological map of Los Helados porphyry Cu-Au deposit......................................Figure 2.2. E-W cross-section (line 6864800 E) showing lithology in depth at the Los Helados porphyry Cu-Au deposit.............................................................................................................Figure 2.3: N-S cross-section  (line 443400 N) showing lithology in depth at the Los Helados porphyry Cu-Au deposit.............................................................................................................Figure 2.4: Photographs of the Granite in outcrop and drill core. A) Andesite dike is cutting fresh granite (441100E-6864760N-UTM-19S). B) LHDH66- 4 m. Fresh granite. C) LHDH28- 38 m. Granite with hematite oxidized mafic minerals. D) LHDH29-38 m. Granite with sericitic alteration and disseminated pyrite.............................................................................................Figure 2.5: Photographs and microphotographs illustrating the aspect of Feldspar Phyric Rhyodacites in drill core samples and outcrops. A) LHDH71- 20 m. Pyrite vein is cutting the sample. B) LHDH13- 347 m. Phenocrysts of plagioclase up to 2.5 mm. C)- D) LHDH28- 90 m (sample AG0028). Microphotographs taken under plane-polarized light (C) and under cross-polarized light (D) showing feldspars altered to sericite...........................................................479121617181921xvii2222252627282931Figure 2.6: Gabbro-Diorite (sample AG 0026, 443208E- 6865700 N-UTM-19S). A) Fresh outcrop. B-C) Thin section from fresh outcrop taken under cross-polarized light and parallel light, respectively...........................................................................................................................Figure 2.7: 206PB/238U vs. 207Pb/235U Concordia plots and weighted mean dates of Gabbro-Diorite (sample AG0026, 443208E-6865700N-UTM-19S)........................................Figure 2.8: Quartz Feldspar Porphyry A) Sample from outcrop (sample AG129, 442702E-6864538N-UTM-19S). B) Sample from outcrop with sericitic alteration (sample AG130, 442705E-6864538S-UTM-19S). (C-D) Microphotographs from B taken under plane-polarized light (C) and under cross-polarized light (D)................................................Figure 2.9: 206Pb/238U vs. 207Pb/235U Concordia plots and weighted mean dates of QFP (sample AG129, 442702 E- 6864538 N-UTM-19S).................................................................Figure 2.10: Photos and thin sections from Fine Grained Plagioclase Crowded Porphyry. A) LHDH72- 806. B) LHDH50- 1210.  C) LHDH50 -1200. (D-E) Microphotographs taken under plane-polarized light (D) and under cross-polarized light (E) .....................................Figure 2.11: 206Pb/238U vs. 207Pb/235U Concordia plot of FGPCP (sample AG0012, LHDH21- 554 m)....................................................................................................................Figure 2.12: Photograph of the Matrix Rich breccia. A) LHDH58- 440 m, 0.41% Cu. granite and undifferentiated rounded clasts cut by a quartz-chalcopyrite vein. B) LHDH44-822 m, 0.32% Cu. Matrix Rich Breccia with large rounded clast of biotitized Gabbro-Diorite. C) LHDH62- 1046 m, 0.52% Cu. Matrix Rich Breccia showing clast andesite and undifferentiated. Quartz vein cut the sample. D) LHDH43-828 m, 0.43 % Cu. Rounded granite containing pre-brecciation vein fragment.........................................................................................................Figure 2.13: Photos of drillcore showing Cement Rich Breccia examples. A) LHDH24-320 m,0.53% Cu. Clast supported matrix with magnetite-chalcopyrite cement. B) LHDH27-1070 m. 0.67 % Cu. Cement dominated (magnetite-biotite-chalcopyrite) with matrix breccia. C) LHDH 17-373 m. 0.69 % Cu. Clast supported breccia with magnetite chalcopyrite cement....................................................................................................................................xviiiFigure 2.14: Photos of drillcore showing Cement Rich Breccia examples A) LHDH30- 390 m. 0.56% Cu. Tourmaline- Pyrite-Chalcopyrite cement. B) LHDH40-329 m, 0.9 %Cu. Tourmaline-Pyrite-Chalcopyrite cement. C) LHDH50- 92 m. Pyrite-gypsum cement.........................................................................................................................................Figure 2.15: Bimodal Plagioclase Porphyry (BiPP). A) LHDH48- 171 m. BiPP with Andesite xenolith. B) LHDH48- 252 m. BiPP with a Gabbro-Diorite xenolith. C)LHDH21- 260 m (sample AG0010) D) LHDH21- 260 m (sample AG0010). Microphotograph taken under plane-polarized light. E) LHDH21- 260 m (sample AG0010) Microphotograph taken under cross-polarized light....................................................................................................................Figure 2.16: 206Pb/238U vs. 207Pb/235U Concordia plot of BiPP(sample AG127, 442822E-6864601N- UTM-19S)................................................................................................Figure 2.17: Photos of Biotite Plagioclase Porphyry. A) LHDH26- 990 m. B) LHDH50-1210 m. C) LHDH17- 499 m. (D-E) LHDH21- 725(sample  AG0013). Microphotographs taken under plan-polarized and cross-polarized light......................................................... ..................Figure 2.18: 206Pb/238U vs. 207Pb/235U Concordia plot of BPP (sample AG0013)..............Figure 3.1. Alteration map of the Los Helados porphyry Cu-Au deposit, modified from Devine (2015 ). .....................................................................................................................................Figure 3.2. Detail of alteration map in Figure 3.1 modified from Devine, 2015 (NGex report)..........................................................................................................................................Figure 3.3: E-W cross-section (line 6864800 E) showing the distribution of lithologies and alteration types in depth at the Los Helados porphyry Cu-Au deposit (see Figure 3.2)............Figure 3.4:  N-S cross-section (line 443400 N) showing the distribution of lithologies and alteration types in depth at the Los Helados porphyry Cu-Au deposit (see Figure 3.2)...........Figure 3.5: Drill core sample pictures and photomicrographs showing characteristics of the K-feldspar (potassic) alteration at the Los Helados porphyry Cu-Au deposit. A) LHDH24-482 m. Pervasive replacement of plagioclase by K-feldspar (pink). B) LHDH24-488 m 323334363739404142xixK-feldspar alteration halos. C) LHDH21-1335 m. Alteration in vein halo and groundmass. D) LHDH21-1335 m. K -feldspar alteration on Matrix Rich Breccia. Note K-feldspar here is white (confirmed by cobalt nitrite staining, see appendix A, sample AG217)). The left side of the photo shows a sharp contact with the biotitized Gabbro-Diorite. E-F) LHDH21-1399 m (sample AG0018). Microphotograph and drill core sample picture of the biotitized Gabbro-Diorite. Hand sample shows a quartz-anhydrite vein. Abbreviations: Al: albite; Biot: biotite; Kfs: potassic feldspar; Qz: quartz..............................................................................................Figure 3.6: Drill core samples showing Sericite-chlorite-magnetite alteration. A) LHDH21-387 m. Feldspars are replaced by sericite, and mafic minerals are replaced by chlorite and magnetite. Late pyrite vein with sericitic halo is cutting the sample B) LHDH12- 545 m. Feldspars are replaced by sericite, and mafic minerals are replaced by chlorite and magnetite. Chalcopyrite veins are cutting an older quartz vein. C) LHDH24-380 m (AG210). Matrix Rich Breccia with magnetite-hematite-pyrite-chalcopyrite cement. D) LHDH24- 380 m (sample AG210). Microphotographs taken under cross-polarized light. Abbreviations: Cpy: chalcopyrite; Chl: chlorite; Mg: magnetite; Qz: quartz; Py: pyrite;  Ser:sericite.....................Figure 3.7: Drill core and outcrop photographs illustrating the characteristics of Sericitic alteration. A) LHDH50- 92 m (sample AG201).Jigsaw breccia cemented by pyrite. B) LHDH50- 92  (sample AG201). Microphotograph under cross-polarized light. Angular clasts totally altered to quartz and sericite cemented by pyrite. C) Outcrop of Feldspar Phyric Rhyodacite (442613E-6864811N-UTM-19S) with intense sericitic alteration cut by a stockwork of quartz veins. D)  LHDH27- 200m. Granite with intense sericitic alteration cut by quartz and pyrite veins. E). Outcrop of the Bimodal Plagioclase Porphyry (442490E-6864597N-UTM-19S) showing an example of weak sericitic alteration F) LHDH21-260 m (sample AG0010). Bimodal Plagioclase Porphyry. Microphotographs taken under cross-polarized light. Shows plagioclases partially altered to sericite. Abbreviations: Cpy: chalcopyrite; Qz: quartz; Py: pyrite..........................................................................................................................................Figure 3.8: The downhole strip log for LHDH24 comparing visual observations, geochemical data (copper and gold grades. The geochemical data is from NGEX), and SWIR results (Appendix D). The black boxes indicate the three zones described in the text. Dots are the value of the 2200 absorption feature; the color of the dot represents the alteration type...........Figure 3.9: SWIR spectra from LHDH24 drill core samples that show the presence of muscovite. With increasing depth, the shape of the spectra changes and the 2200nm feature shifts to indicate a more phengitic (Fe-rich) muscovite composition......................................4446485354xxFigure 3.10: LHDH 28- 560 m. Cross-cutting relationship in Fine Grained Plagioclase Crowded Porphyry. Numbers refer to the Code in Table 3.5. Abbreviations: Bio: biotite; Cpy: chalcopyrite; Kfs: potassium feldspar; Mo: molybdenite; Py: pyrite; Qz: quartz............Figure 3.11: LHDH50-1222 m. Cross-cutting relationship in Fine Grained Plagioclase Crowded Porphyry. Type 2a vein cut by younger vein types. Vein numbers refer to the codes in Table 3.5. Abbreviations: Kfs: potassium feldspar; Qz: quartz.............................................Figure 3.12: LHDH21-285 m. Cross-cutting relationship in Feldspar Phyric Rhyodacite. Numbers refer to the Code in Table 3.5. Abbreviations: Cpy: chalcopyrite; Py: pyrite Qz: quartz.............................................................................................................................................Figure 3.13: LHDH 28-775 m. Cross-cutting relationship in Feldspar Phyric Rhyodacite. Numbers refer to the Code in Table 3.5. Abbreviations: Cpy: chalcopyrite; Py: pyrite Qz: quartz; Ser: sericite....................................................................................................................Figure 3.14: LHDH 13-353 m. Cross-cutting relationship in Bimodal Plagioclase Porphyry. Numbers refer to the Code in Table 3.5. Abbreviations: Mg: magnetite; Py: pyrite, Qz: quartz..............................................................................................................................................Figure 3.15: LHDH72-506 m. Cross-cutting relationship in Matrix Rich Breccia. Numbers refer to the Code in Table 3.5. Abbreviations: Cpy: chalcopyrite; Mg: magnetite; Qz: quartz.............................................................................................................................................Figure 3.16: LHDH24-323 m. Cross-cutting relationship in Feldspar Phyric Rhyodacite. Numbers refer to the Code in Table 3.5. Abbreviations: Anhy: anhydrite; Cpy: chalcopyrite; Py: pyrite; Qz: quartz...............................................................................................................Figure 3.17: Schematic cross-cutting relationships between the veins and their classification into three distinct phases at Los Helados porphyry Cu-Au deposit. The relative timing of alteration types and total vein density are also shown in relation to the vein paragenesis. Vein numbers refer to the codes in Table 3.4. Abbreviations: Miocene intrusives: BPP: Biotite Plagioclase Porphyry; BiPP: Bimodal Plagioclase Porphyry; FGPCP; Fine Grained Plagioclase Crowded Porphyry; QFP: Quartz Feldspar Porphyry. Minerals: Bio: biotite; Chl: chlorite Epi: epidote; Kao: kaolinite; Kfs: potassium feldspar; Mg: magnetite; Pyr: pyrophyllite; Ser: sericite.......................................................................................................................................5757575959595961xxiFigure 3.18: Drill core photographs and reflected light photomicrograph illustrating hypogene Cu-Sulfide mineralization in breccias at Los Helados porphyry Cu-Au deposit. (A-B) LHDH50-93 m (AG201). Jigsaw breccia cemented by pyrite. (C-D) LHDH13-358 m (sample AG211). Matrix Rich Breccia with acicular crystals of hematite, pyrite, and chalcopyrite. Abbreviations: Cpy: chalcopyrite; Hm: hematite; Py: pyrite...................................................Figure 3.19: Drill core Photographs and reflected light photomicrograph illustrating hypogene Cu-Sulfide mineralization in breccias in the chalcopyrite-pyrite zone (A-B-C-D) and chalcopyrite zone (E-F) at Los Helados. (A-B) LHDH30-741 m (sample AG204). Cement rich breccia with chalcopyrite, pyrite, magnetite and hematite cement. (C-D) LHDH50-679 m (AG202). Cement Rich Breccia cemented by- chalcopyrite magnetite and less pyrite (E-F) LHDH34-920 m (sample AG200). Vein of chalcopyrite (Vein type 2C) with traces of molybdenite...............................................................................................................................Figure 3.20: E-W cross-section (line 6864800 E) showing the distribution of lithologies, alteration types, sulfides zoning and metal zoning in depth at the Los Helados porphyry Cu-Au deposit.................................................................................................................................Figure 3.21: N-S cross-section illustrating lithology, alteration, sulfides zoning, and metal zoning in depth at the Los Helados porphyry Cu-Au deposit.................................................Figure 4.1: Plot of (2Ca + Na + K)/Al versus K/Al molar (Stanley and Madeisky, 1994; Madeisky, 1996). Rocks from Los Helados have suffered alkaline metasomatism. The trend of the altered rocks toward K-mica (black arrow) agrees with the widespread sericite alteration documented...............................................................................................................................Figure 4.2: Loss on ignition (LOI) vs Total sulfurs (TOT/S). The blue lines indicate values on which it is considered intensely altered and not suitable for rock classification on the basis of major elements (Fulignati et al.1998)..................................................................................Figure 4.3A: Harker-type diagrams for Los Helados porphyry Cu-Au deposit. The dataset exhibits three groups based on the silica content. These three groups can also be discriminated with minor dispersion plotting Al, Y, and Ti. Diagrams of Na2O, K2O, Fe2O3, MgO, CaO, Sr and Ba show a greater dispersion showing that these elements were more mobile during the hydrothermal alteration documented in Los Helados..........................................................64656768707071xxiiFigure 4.3B: Harker-type diagrams for Los Helados porphyry Cu-Au deposit. The dataset exhibits three groups based on the silica content. These three groups can also be discriminated with minor dispersion plotting Al, Y, and Ti. Diagrams of Na2O, K2O, Fe2O3, MgO, CaO, Sr and Ba show a greater dispersion showing that these elements were more mobile during the hydrothermal alteration documented in Los Helados........................................................Figure 4.4 Volcanic rock classification: Winchester and Floyd, 1977. Miocene porphyries samples are classified in the trachy-andesite field. The more felsic Permo-Triassic rocks are classified as rhyodacites while the more mafic rocks fall towards the border andesite/basalt and sub alkali basalt fields.......................................................................................................Figure 4.5: Primitive mantle normalized trace element plot (McDonough et al., 1992). All units reveal typical patterns of subduction-related magmas....................................................Figure 4.6: Multi-element and REE spider diagram. Data is normalized to chondrite (Sun and McDonough, 1989). Los Helados units can be grouped into three groups based on the REE distribution patterns (Granite and Feldspar-Phyric Rhyodacites; Gabbro-Diorite; and Miocene porphyries)................................................................................................................Figure 4.7: A). Plot of Sr/Y vs. Y (Defant and Drummond, 1993). This plot shows that Miocene rocks from Los Helados all meet the criteria proposed for the definition of adakites B) La/Yb vs. silica (Richards and Kerrich, 2007). This plot indicates fractionation of garnet and amphibole for the Miocene rocks.......................................................................................Figure 5.1: W-E cross-section at 6864800 N. Reconstruction of the pre-Miocene and Miocene magmatic hydrothermal history of Los Helados porphyry Cu-Au deposit..............................Figure 5.2: Timetable based on geochronological data obtained on zircons (this thesis) and molybdenite (NGEx Minerals Inc. internal data), geological mapping, and core logging. ....Figure 5.3: Comparison between Los Helados Cement Rich Breccia and breccia Sur-Sur from Los Bronces. The figures use the same vertical scale. The central column indicates the variation of the hydrothermal cement according to the depth. The drawings were made on the same scale. The Sur-Sur Breccia drawing is modified from Frikken (2005)....................7273767779828385xxiiiFigure 5.4: Modified from Murakami et al., (2010). Relationships between Cu/Au ratio and depth. The estimated depth of porphyry-style deposits decreases with decreasing Cu/Au ratio. Solid lines are showing fitted trends for geological depth estimates (blue) and fluid inclusion microthermometry (red). The dashed vertical line indicates a molar Cu/ Au ratio of 4.0×104 as defined in Kesler et al. (2002) to separate copper-gold deposits from copper ± molybdenum deposits. The solid black vertical line indicates the Cu/Au molar ratio of Los Helados....................................................................................................................................Figure 5.5: E-W cross-section showing alteration domains and the variation of the 2200nm absorption feature with depth.....................................................................................................Figure 5.6: Relationship of the wavelengths of the 2200 absorption feature, copper grade, and depth for drillhole LHDH24 (see appendix D for SWIR data). Dashed lines in the uppermost window represent the zones described for the E-W cross-section. Yellow triangles represent superposition of sericite alteration (telescoping) over earlier sericite-magnetite-chlorite alteration...................................................................................................................................Figure 5.7: Location of Los Helados porphyry Cu-Au deposit respect to the Maricunga and El Indio belt. It also shown latest Oligocene- Miocene porphyry and high-sulfidation (HS) epithermal deposits in the El Indio and Maricunga metallogenetic belts, northern Chile. Modified from Cahill and Isacks (1992)...................................................................................Figure 5.8: Volcanic and hypabyssal rocks and porphyry/epithermal deposits of the Maricunga and El Indio metallogenic belts (Compiled by Gamonal 2015). The four periods are well represented in the Maricunga belt but to the south of 28, volcanic activity is only represented by rocks of the period 21-17 Ma..............................................................................................Figure 5.9: Map showing the distribution of the Late Paleozoic to Late Triassic rocks of northern Chile between latitudes 26° and 31°S (Modified from Maksaev 2014) showing the locations of “translithospheric” regional-scale faults (modified from Carrizo and Herrera (2019) and referenced therein)..................................................................................................Figure A1: Hand sample. Sample AG0001. ............................................................................Figure A2: Thin section-XLP. Sample AG0001.......................................................................8890919598101120120xxivFigure A3: Microphotograph: Magnification 2X   XLP. Sample AG0001...............................Figure A4: Hand sample. Sample   AG003. ...........................................................................Figure A5: Thin section-XLP. Sample   AG003.......................................................................Figure A6: Microphotograph. Magnification 2X -XLP. Sample   AG003...............................Figure A7: Hand sample Photograph. Sample AG0002...........................................................Figure A8: Thin section-XLP. Sample AG0002. ....................................................................Figure A9: Hand sample Photograph. Sample AG0004. ........................................................Figure A10: Thin section-XLP. Sample AG0004....................................................................Figure A11: Microphotograph. Magnification 2X -XLP. Sample AG0004.............................Figure A12: Hand sample Photograph. Sample AG0005......................................................... Figure A13: Thin section-XLP. Sample AG0005.....................................................................Figure A14: Microphotograph: Magnification 2X -XLP. Sample AG0006. ...........................Figure A15: Thin section-XLP. Sample AG0006. ..................................................................Figure A16: Hand sample Photograph. Sample AG0007..........................................................Figure A17: Thin section-XLP. Sample AG0007......................................................................Figure A18: Microphotograph Magnification 2X -XLP. Sample AG0007................................Figure A19: Hand sample Photograph. Sample AG0008.........................................................120121121121122122123123123124124125125126126126127xxvFigure A20: Thin section-XLP. Sample AG0008.......................................................................Figure A21: Hand sample Photograph. Sample AG0009...........................................................Figure A22: Thin section-XLP. Sample AG0009......................................................................Figure A23: Microphotograph Magnification 20X -XLP. Sample AG0009.  ...........................Figure A24: Hand sample Photograph. Sample AG0010...........................................................Figure A25: Thin section-XLP. Sample AG0010......................................................................Figure A26: Hand sample Photograph. Sample AG0011............................................................Figure A27: Thin section-XLP. Sample AG0011.......................................................................Figure A28: Hand sample Photograph. Sample AG0012. ........................................................Figure A29: Thin section-XLP. Sample AG0012......................................................................Figure A30: Microphotograph Magnification 5X -XLP. Sample AG0012. ..............................Figure A31. Hand sample Photograph. Sample AG 0013. ........................................................Figure A32: Thin section-XLP. Sample AG 0013. ...................................................................Figure A33: Hand sample Photograph. Sample AG0014. ........................................................Figure A34: Thin section-XLP. Sample AG0014.......................................................................Figure A35: Microphotograph Magnification 2X -XLP. Sample AG0014................................Figure A36: Hand sample Photograph. Sample AG0015..........................................................127128128128129129130130131131131132132133133133134xxviFigure A37: Thin section-XLP. Sample AG0015.......................................................................Figure A38: Hand sample Photograph. Sample AG0016...........................................................Figure A39: Thin section-XLP. Sample AG0016.......................................................................Figure A40: Hand sample Photograph. Sample AG0018.........................................................Figure A41: Thin section-XLP. Sample AG0018........................................................................Figure A42: Microphotograph Magnification 2X -XLP. Sample AG0018.................................Figure A43: Hand sample Photograph. Sample AG0019...........................................................Figure A44: Thin section-XLP. Sample AG0019.......................................................................Figure A45: Microphotograph Magnification 2X -XLP. Sample AG0019. ...............................Figure A46: Thin section-XLP. Sample AG0020......................................................................Figure A47: Hand sample Photograph. Sample AG0021..........................................................Figure A48: Thin section-XLP. Sample AG0021......................................................................Figure A49: Microphotograph. Magnification 2X -XLP. Sample AG0021..............................Figure A50: Hand sample Photograph. Sample AG0022.........................................................Figure A51: Thin section-XLP. Sample AG0022.....................................................................Figure A52: Microphotograph.  Magnification 2X -XLP. Sample AG0022..............................Figure A53: Outcrop Photograph. Sample AG0023. ................................................................134135135136136136137137137138139139139140140140141xxviiFigure A54: Thin section-XLP. Sample AG0023......................................................................Figure A55: Hand sample Photograph. Samples AG0024 and AG0025...................................Figure A56: Thin section-XLP. Samples AG0024 and AG0025...............................................Figure A57: Microphotograph. Magnification 2X -XLP. Samples AG0024 and AG0025........Figure A58: Thin section-XLP. Sample AG0026.....................................................................Figure A59: Hand sample Photograph. Sample AG0027. ........................................................Figure A60: Hand sample Photograph. Sample AG0028..........................................................Figure A61: Thin section-XLP. Sample AG0028......................................................................Figure A62: Hand sample Photograph. Sample AG0029.........................................................Figure A63: Thin section-XLP. Sample AG0029.......................................................................Figure A64: Hand sample Photograph. Sample AG200............................................................Figure A65: Thin section-XLP. Sample AG200. .....................................................................Figure A66: Microphotograph. Magnification 10X -XLP. Sample AG200..............................Figure A67: Hand sample Photograph. Sample AG201............................................................Figure A68: Thin section-XLP. Sample AG201........................................................................Figure A69: Microphotograph: Magnification 2X -XLP. Sample AG201................................Figure A70: Hand sample Photograph. Sample AG202. ........................................................141142142142143144145145146146147147147148148148149xxviiiFigure A71: Thin section-XLP. Sample AG202........................................................................Figure A72: Microphotograph. Magnification 20X -XLP. Sample AG202. ............................Figure A 73: Hand sample Photograph. Sample AG 203.........................................................Figure A74: Thin section-XLP. ample AG 203........................................................................Figure A75: Microphotograph. Magnification 2X -XLP. ample AG 203.................................Figure A76: Hand sample Photograph. Sample AG204.  ........................................................Figure A77: Thin section-XLP. Sample AG204.  ....................................................................Figure A78:  Microphotograph. Magnification 2X -XLP. Sample AG204.  ...........................Figure A79: Hand sample Photograph. Sample AG205. ......................................................... Figure A80: Thin section-XLP. Sample AG205.......................................................................Figure A81: Microphotograph. Magnification 2X -XLP. Sample AG205...............................Figure A82: Hand sample Photograph. Sample AG206. ........................................................Figure A83: Thin section-XLP. Sample AG206. .....................................................................Figure A84: Microphotograph. Magnification 2X -XLP. Sample AG206. .............................Figure A85: Hand sample Photograph. Sample AG207. ........................................................Figure A86: Thin section-XLP. Sample AG207. .....................................................................Figure A87: Microphotograph. Magnification 2X -XLP. Sample AG207. .............................149149150150150151151151152152152153153153154154154xxixFigure A88: Hand sample Photograph. Sample AG208.  ........................................................Figure A89: Thin section-XLP. Sample AG208.  .....................................................................Figure A90: Microphotograph. Magnification 2X -XLP. Sample AG208.  .............................Figure A91: Hand sample Photograph. Sample AG210.........................................................Figure A92: Thin section-XLP. Sample AG210. .....................................................................Figure A93: Microphotograph. Magnification 10X -XLP. Sample AG210. ............................Figure A 94: Hand sample Photograph. Sample AG211.........................................................Figure A 95: Thin section-XLP. Sample AG211......................................................................Figure A96: Hand sample Photograph. Sample AG217...........................................................Figure A97: Thin section-XLP. Sample AG217........................................................................Figure A98:  Cobalt nitrite staining: Yellow stain indicates K-feldpar. Sample AG217.........Figure C1: Concordia diagram. Sample AG0013......................................................................Figure C2: zircon detail of sample AG0013.............................................................................Figure C3: AG127 concordia diagram. Sample AG127.........................................................Figure C4: AG127 concordia diagram, youngest details...........................................................Figure C5: Zircons detail of sample AG127.............................................................................155155155156156156157157158158158171171172172172xxxFigure C6: Concordia diagram. Sample AG0012.....................................................................Figure C7: Concordia diagram (youngest details). Sample AG0012. .....................................Figure C8: Zircons of AG0012 sample......................................................................................Figure C9: Concordia diagram. Sample AG129.......................................................................Figure C10: Youngest data of Concordia diagram. Sample AG129.........................................Figure C11: Zircon of sample AG129.......................................................................................Figure C12: Weighted mean 206Pb/238U CA-TIMS dates of sample AG129........................Figure C13: Concordia diagram. Sample AG0026...................................................................Figure C14: Weighted mean 206Pb/238U CA-TIMS dates of sample AG0026.......................Figure E1: X-ray pattern form Los Helados drill hole. LHDH20 at 150 m.............................Figure E2: X-ray pattern form Los Helados drill hole. LHDH20 at 330 m. ............................Figure E3: X-ray pattern form Los Helados drill hole. LHDH20 at 330 m..............................Figure E4: X-ray pattern form Los Helados drill hole. LHDH20 at 590 m..............................Figure E5: X-ray pattern form Los Helados drill hole. LHDH20 at 640 m...............................Figure E6: X-ray pattern form Los Helados drill hole. LHDH20 at 720 m...............................Figure E7: X-ray pattern form Los Helados drill hole. LHDH24 at 60 m...............................Figure E8: X-ray pattern form Los Helados drill hole. LHDH24 at 130 m...............................173173173174174174174175175204205206207208209210211xxxiFigure E9: X-ray pattern form Los Helados drill hole. LHDH24 at 290 m...............................Figure E10: X-ray pattern form Los Helados drill hole. LHDH24 at 460 m.............................Figure E11: X-ray pattern form Los Helados drill hole. LHDH24 at 630 m...........................Figure E12: X-ray pattern form Los Helados drill hole. LHDH24 at 700 m...........................Figure F1: Examples of drill core logging.................................................................................Figure G1:  Drill hole location and drill hole traces.................................................................212213214215217227xxxiiAuEq  cm  DH  E  g/t   km   Lat  LOI  Long   m   mm   nm Ma   MORB   Moz   gold equivalentcentimeterdiamond drillingEastgrams per tonkilometer latitudelost of ignitionlongitudemetermillimeternanometremillion of years oldmid-ocean ridge basaltmillion of ouncesList of abbreviationsxxxiiiN    PCDs PPL  REE   RC RL  S  SWIR  Tqv W  XPL XRD  Ag  Al Alu   northporphyry copper deposits plane polarized light rare earth elementsreverse circulationreflected light Southshort-wave infraredtruncated quartz veinWestcross polarized light x-ray diffraction silveralbitealuniteMineral abbreviationsxxxivAnhy Bio Bn  Chl  Cov Cpy  Cu  Dik Epi  Gar  Gyp  Hem  Ill Kao Kfs Mg anhydritegoldbiotitebornitechloritecovellitechalcopyritecopperdickiteepidotegarnetgypsumhematiteillitekaolinitepotassic feldsparxxxvMo  Musc  Plag Pyr  Qz Rt  Ser  Sp  Tour  AND  BiPP BPP CRBX FGPCP FPRmolybdenitemuscoviteplagiclasepyrophyllitequartzrutilesericiteespecularitetourmalineLithology abbreviationsAndesitesBimodal Plagioclase  PorphyryBiotite Plagioclase PorphyryCement Rich BrecciaFine Grained Plagioclase Crowded Porphyry Feldspar Phyric RhyodacitexxxviGA-DIO GRN  MRBC QFP Gabbro-DioriteGraniteMatrix Rich BrecciaQuartz Feldspar Porphyry1Chapter 1. Introduction1.1 OverviewThe Miocene belt of northern Chile is one of the world’s most well-endowed regions for Cu and Au, hosting numerous gold-rich epithermal deposits such as La Coipa, Pascua Lama, El Indio, and Veladero (Martin et al., 1995; Bissig et al., 2001; Holley, 2012; Charchaflié et al., 2007; Gamonal, 2015), as well as gold-rich porphyry deposits such as Cerro Casale and Caspiche (Sillitoe et al., 2013). The earliest discoveries date back to 1975 when the El Indio Au-Ag-Cu deposit was discovered and was developed into a mine in 1981. The success of this discovery triggered intense exploration activity for epithermal deposits in the Andean Cordillera of central and northern Chile which led to the discoveries of many other deposits that led to the recognition of this metallogenic belt between 1980 and 1990 (Vila and Sillitoe 1991; Figure 1.1).In the early 2000s, it was recognized that the newly discovered deposits formed two main belts: the Maricunga to the north (Vila and Sillitoe 1991; Muntean and Einaudi, 2001); and the El Indio to the south (Martin et al., 1995; Bissig et al., 2001; Holley, 2012; Winocur et al., 2014). The area between these two belts gained the attention of explorers and the region emerged as a new exploration focus. This area had previously received less attention partly due to the poor preservation of extensive Miocene volcanic rocks which were incorrectly interpreted as an indication of the deep exhumation and, consequently, low potential for the discovery of Miocene epithermal and porphyry mineral deposits. As a direct consequence of the focused exploration, several important deposits were discovered in the subsequent 15 years, which demonstrates the continuity of Late Oligocene- Miocene mineralization. These discoveries include the porphyry deposits at Caserones (Cu-Mo), Josemaria (Cu-Au) and Los Helados (Cu-Au). Several other promising targets are also still being investigated.All of the porphyry deposits discovered in this region thus far are hosted in Permian-Triassic basement rocks. This is in contrast to both the Maricunga and El Indio deposits which typically have at least part of the system hosted within remnant Late Oligocene-Miocene volcanic rocks. The development of these porphyry deposits within Triassic basement rocks emphasized the lack of understanding of their controlling geological features and their differences that distinguished them from the classic porphyry deposits of the Maricunga belt.The Los Helados deposit was discovered in 2006 by the first diamond drill hole in the area, following-up on promising RC drilling results from the previous exploration season. Hole 1 intersected the main breccia body and intersected 518 m grading 0.47% Cu and 0.31 g/t Ag. The hole followed 2up on the initial identification of a Landsat and ASTER satellite image color anomaly in 2004 and geological mapping, surface geochemical sampling, and geophysical surveys (IP-resistivity and magnetometry) from 2004 to 2006. Key insights from alteration vectoring were an important part of the initial drill targeting. Follow-up drilling in subsequent years increased the size of the known mineralization and led to the drilling of hole 16 in 2010-11, which emphasized the large size of the mineralized system. Hole 16 drilled a 737 m interval of 0.64% copper and 0.30 g/t gold from 40 m downhole. From 2006 to 2015 eight drilling campaigns were carried out totaling 75,634 m in 88 drill holes, including five RC holes (1,366 m), and 83 DDH holes (74,268 m). The current mineral resource estimate for Los Helados (NGEx Resources, 2014) at a base case 0.5 % copper equivalent cut-off is: Indicated Resource: 981 million tonnes at a grade of 0.45 % copper and 0.18 g/t gold for a copper equivalent grade of 0.58%. Inferred Resource: 41 million tonnes at a grade of 0.41% copper and 0.13 g/t gold for a copper equivalent grade of 0.51%.There are several important characteristics of the Los Helados deposit that makes it a prime deposit for study. There is continuous vertical exposure of more than 1800 m of altered and mineralized rock, from the lower part of the advanced argillic alteration to the potassic alteration at the bottom of current drilled depth. Over this distance, there is limited compositional variability of the host rocks which provides an excellent opportunity to determine the anatomy of the magmatic-hydrothermal system through mapping the effects of the hydrothermal fluids on the host rock.Once the geology of the porphyry system at Los Helados is defined, including geologic features such as host rock, style of mineralization, depth of emplacement and alteration, provide the opportunity for comparison with other porphyry systems in the Maricunga belt to the north. The nature of the Los Helados mineral system differs significantly from the porphyry Au (-Cu) and epithermal Au-Ag deposits in the northward-contiguous Maricunga metallogenic belt. Determining the possible reasons for this will benefit regional exploration in the Miocene belt of northern Chile.This thesis presents new geological, geochemical and geochronological data which provides a basis for an increased understanding of the Miocene evolution of Los Helados Cu-Au porphyry. It also provides the opportunity to highlight the differences with nearly coeval deposits of the Maricunga metallogenetic belt. Lastly, new insights from these investigations will increase the mineral exploration success of the Los Helados area for success in future mineral exploration of similar targets.31.2 Objectives of this studyPorphyry deposits form large hydrothermal footprints and it is critical to understand the lateral and vertical alteration zonation within the system for improved vectoring towards higher-quality ore. However, many porphyry systems are hosted by a variety of rock types and may have suffered considerable post-emplacement deformation or erosion that has changed the geometry of the alteration patterns within the system. Los Helados offers a unique opportunity to establish not only the anatomy of a porphyry system without the complexities that many other systems may have, but also its magmatic and hydrothermal evolution. The Miocene belt of northern Chile is characterized by deposits of Maricunga and El Indio metallogenetic belt, but the geological features of Los Helados are markedly different from the classic Miocene deposits. Understanding these differences will help to increse exploration succes in the area of study.The objectives that will help clarify this are:• Establish the Miocene magmatic, and  hydrothermal history by reconstructing the sequence of intrusions of porphyries and breccias and veins that gave rise to the current distribution of hydrothermal alteration assemblages and associated sulfide mineralization.• Determine the three-dimensional geometric zonation in white mica distribution and determine the variations and spatial relationships with copper mineralization.• Establish the differences between Los Helados and deposits from the adjacent metallogenetic belts determining the possible reasons that produced the dissimilarities and define exploration guidelines.1.3 Location and access and climate.Los Helados Cu-Au porphyry deposit is located about 125 km southeast of the city of Copiapó (approximately 130,000 inhabitants) within the Chilean Andes at an elevation of 4,500 masl, at 28.34° S latitude and 69.58° W longitude (Figure 1.1). The deposit is accessed by road approximately 170 km or 2.5 hours of driving from Copiapó: A well-maintained sealed C-35 road passes southeast through the towns of Tierra Amarilla and Los Loros, and then the C-453 road towards the El Potro bridge. From there, driving 1 hour on a private road leads to the Los Helados camp.4The climate is dry to arid, with moderate to cold temperatures, annual precipitation of about 250 mm, and snow at higher elevation during the winter season. Fieldwork is generally restricted to mid-October - early May due to possible heavy snowfall and low temperatures.Figure 1.1: Location of Los Helados with respect to other well-known deposits from northern Chile within the El Indio and Maricunga metallogenic belts. Modified from Cahill and Isacks (1992).51.4 Metallogenic setting: description of El Indio and Maricunga beltsAlthough the Maricunga and El Indio belts are well known, there is sparse published geological information of the area between them. However, the discovery and development of new deposits such as Caserones, Los Helados and Josemaria during the last decade has demonstrated the potential and the economic importance of this intermediate area.1.4.1 The Maricunga beltThe Maricunga belt was defined by Vila and Sillitoe (1991) as an N-NE trending chain of andesitic to dacitic composite volcanoes of Miocene age, roughly 200 x 50 km in extent, between latitudes 26°S and 28° S and 4000 to 6000 masl. It is situated along the southwestern edge of the Altiplano- Puna plateau, close to the southern boundary of the active Central Volcanic Zone of the Andes with a non-volcanic segment between 28° and 33°S — the non-volcanic segment is widely attributed to shallow-angle subduction of the Nazca plate (commonly referred to as the Chilean or Pampean “flat-slab”) (Thorpe et al., 1982; Cahill and Isacks, 1992; Kay and Mpodozis, 2002) (Figure 1.1).The geology of this belt is described in numerous works, including Segerstrom (1968), Zentilli (1974), Mercado (1982), Vila and Sillitoe (1991); Davidson and Mpodozis (1991), Mpodozis et al. (1995), and Gamonal (2015) (Figure 1.2). The basement to the Maricunga belt comprises metasedimentary and felsic volcanic rocks and granitoids of late Paleozoic age. An unconformity separates the Paleozoic basement from the Triassic bimodal volcanic and sedimentary rocks that were deposited in extensional rift basins, and Jurassic to Early Cretaceous marine and continental sedimentary rocks that were deposited in a backarc basin that developed throughout northern Chile (Mercado, 1982; Mpodozis et al., 1995; Cornejo et al., 1998; Iriarte et al., 1999; Arriagada et al., 2006). In the southern Maricunga belt, an unconformity separates Paleocene volcanic units and Oligocene continental sedimentary sequences which are composed of red sandstones, siltstones, and conglomerates, including evaporitic horizons (Mpodozis and Kay, 2003).Early work by Vila and Sillitoe (1991) divided the Maricunga belt into four periods of volcanic activity (Vila and Sillitoe, 1991; Mpodozis et al., 1995; Gamonal, 2015): 1) Oligocene to early Miocene (26 – 21 Ma), 2) Early Miocene (21 - 17 Ma), 3) Early to mid-Miocene (17 - 11 Ma), and 4) Mid Miocene to Pliocene (11 - 4 Ma).The first epoch started in the late Oligocene to early Miocene (26 – 21 Ma) with the initiation of arc magmatism in this zone when the reorganization of Pacific plate motions led to the breakup of the 6Farallon plate into the Nazca and Cocos plates (Lonsdale, 2005). Volcanic activity and extensive hydrothermal alteration occurred during this event under a neutral to weakly extensional tectonic setting (Sillitoe et al.,2013). Volcanic centers included the large andesite stratovolcanoes and the mineralized Esperanza and La Coipa dacitic dome clusters in the north, and small dome complexes of La Pepa, Pantanillo and Refugio that host gold-silver epithermal mineralization in the south.The second epoch in the early Miocene from 21 to 17 Ma was characterized by a compressive tectonic setting associated with slab flattening (Mpodozis et al., 1995; Kay et al., 1994, 2008; Kay and Mpodozis, 2001). The contraction resulted in diminished volcanism, compressive deformation, and crustal thickening (Kay et al., 1994; Mpodozis et al., 1995). As a consequence, few mineral deposits formed during this period. The northern segment of the Maricunga belt includes the Atlas and Titán high-sulfidation epithermal prospects and at the southern end is the Caserones Cu-Mo porphyry deposit which is the only known occurrence of mineralization that can be assigned to this period.During the third metallogenic epoch (17 to 11 Ma), voluminous volcanic activity took place under more extensional conditions. Volcanic activity resumed with great intensity and generated several sets of compound stratovolcanoes (Kay et al.,1994), which extend through for >200 km of the Maricunga metallogenic belt. During the final stages of this volcanic episode (13-11 Ma), the belt was characterized by a period of mineralization that was associated with the emplacement Au porphyries. The mineralized areas are associated with Marte, Lobo, Escondido, Valy, and at the southern end of the belt, the mineralized porphyry of Co. Casale.From 11 Ma to 4 Ma the last metallogenic epoch was characterized by renewed contractional tectonism and marked geographic restriction of volcanism. Erosion of Miocene volcanoes exposed subvolcanic porphyry stocks, many of which are hydrothermally altered (Vila and Sillitoe, 1991).Several of the alteration zones host high-sulfidation epithermal Au-(Ag) and porphyry Au-(Cu) deposits. The high-sulfidation epithermal deposits include large-tonnage low-grade deposits (e.g., La Coipa; Oviedo et al., 1991) and bonanza-type veins (e.g., La Pepa). The porphyry Au-(Cu) deposits (e.g., Refugio, Cerro Casale, Caspiche, La Pepa, Marte, and Lobo) associated with quartz veinlets are hosted mainly by subvolcanic porphyry intrusions. The main host rock for both key deposit types the Maricunga deposits are volcanic rocks7Figure 1.2: Generalized geology of the Maricunga belt (modified from Vila and Sillitoe, 1991 and Maksaev et al., 2014). Both Western (24 – 20 Ma) and Eastern (14 – 13 Ma) Sub-belts are also indicated.81.4.2 El Indio beltThe El Indio belt is located on the crest of the Andes along the Argentina-Chile border between 29°S and 31°S above the present-day flat-subducting slab zone (Figure 1.1). The belt is defined by a series of advanced argillic lithocaps and containing high-sulfidation epithermal Au-Ag±Cu deposits and prospects. These deposits are confined between two reverse faults with opposite dips, the Baños del Toro Fault to the West and the Colangüil Fault in the East (Martin et al., 1995, Bissig et al., 2002) (Figure 1.3).The main deposits in this metallogenetic belt were emplaced between 9.4 and 6.2 Ma (Bissig et al., 2001). The El Indio system, a high-grade vein-hosted system with assemblages either of high- and intermediate-sulfidation (Deyell et al., 2004), has been dated between 7.8 and 5.0 Ma (Bissig et al., 2001; Deyell et al., 2004; Bissig et al., 2015). Pascua-Lama (26 Moz Au) is a high-sulfidation epithermal deposit that is hosted by several hydrothermal breccias (Deyell et al., 2004; Chouinard et al., 2005), with the main pulse of mineralization at 8.80 ± 0.60 Ma (40Ar/39Ar alunite; Deyell et al., 2005). Veladero (11 Moz Au) is a high-sulfidation system with mineralizing ages constrained between 12.70 ± 0.20 Ma and 8.58 ± 0.17 Ma (40Ar/39Ar alunite and jarosite, respectively; Holley, 2012).The basement rocks of the El Indio belt comprise Permian to Jurassic Choiyoi Group in Argentina (Charchaflié et al., 2007) and the age-equivalent Pastos Blancos Group in Chile (Bissig et al., 2001). Hypabyssal diorites of 36 to 30 Ma Bocatoma Unit (Martin et al., 1995; Bissig et al., 2001) intruded the basement, and both units are unconformably overlain by a thick sequence of late Oligocene volcanic and volcaniclastic rocks that were deposited in an extensional setting throughout the region (Winocur et al., 2015). This Oligocene to upper Miocene volcanic stratigraphy is represented by > 1500 m of subaerial volcanic rocks (Tilito Formation, Escabroso Group and Cerro de las Tórtolas Formation) and hypabyssal stocks (Infiernillo Unit) (Martin et al., 1995; Bissig et al., 2002; Gamonal, 2015; Winocur et al., 2015). After deposition of the Cerro Las Tórtolas Formation, volcanic activity decreased markedly and was represented by isolated dacitic ignimbrites of the Vacas Heladas Formation (12.8 to 11 Ma (Bissig et al., 2001)), and rhyolitic tuffs and volcaniclastic sedimentary rocks grouped in the Vallecito Formation (6.10 ± 0.40 to 5.50 ± 0.40 Ma (Holley, 2012)).9Figure 1.3: Regional simplified geology of the El Indio-Pascua belt and location of mined deposits and major prospects (modified from Bissig et al., 2015).101.5 History of explorationIn the area around Los Helados, local residents have indicated that the earliest mineral exploration was carried out by Shell (subsequently Billiton) in the late 1980s (NGEx Resources Inc/ Anonymous, 2010). This work included geological mapping, accompanied by rock, talus and stream sediment geochemical sampling, as part of a regional exploration program. In 1994, Barrick Gold Corporation conducted a 15-day stream sediment and rock sample geochemical survey in the Los Helados vicinity, but the results of this survey are unknown.In 2004 NGEx initiated a regional exploration survey comprising Landsat and ASTER satellite imagery analysis, outlining an alteration anomaly. The initial concessions were acquired in 2004. Preliminary mapping, rock-chip, and talus geochemical sampling were conducted in early 2005. Additional geochemistry, as well as IP-resistivity and magnetometry geophysical surveys were performed during the 2005-06 summer season. During the season 2006-2007, the first drilling campaign consisted of seven RC holes (1,366 m) designed to test the geophysics and geochemical anomalies. In the following seasons, seven diamond drill hole campaigns were carried out from 2007 to 2013 totaling 83 DDH holes (74,268 m). Mineral Resource estimates were completed on behalf of NGEx in 2012 and updated in 2013 and 2014.1.6 Porphyry copper depositsPorphyry copper deposits (PCDs) are large volumes of rock that form high-tonnage (greater than 100 million tons), low- to moderate-grade (0.3–2.0 % copper) ores (Richards,2003; Sillitoe, 2010). The ores consist of disseminated copper minerals and copper-bearing veins and breccias. The host rocks are highly-altered and may be volcanic rocks that are genetically-related to slightly younger granitoid or hypabyssal porphyry intrusions. Widespread and distinctive zones of hydrothermal alteration provide a useful footprint for explorers. Recent reviews of these characteristics are provided by Hedenquist and Richards (1998), Kerrich et al. (2000), Tosdal and Richards (2001), Richards (2003), Cooke et al. (2005) and Sillitoe (2010).PCDs are the most important source of copper in the world, and also are an important source of other metals, notably molybdenum, gold, and silver. By-product of rhenium, tellurium, platinum group elements, arsenic, and zinc are recovered from a few deposits. Despite their relatively low grades, PCDs have a significant societal and economic impact due to their size (hundreds of millions to billions of metric tons), long mine lives, and scale of mining operations. PCDs were the first type of metallic mineral deposit exploited by large-scale, open-pit mining methods in the early 20th century, a low-cost mining technique since then adapted to other large-tonnage, low-11grade mineral deposits.These deposits mostly form in time and space within the evolution of magmatic arcs along convergent plate margins where subduction of oceanic crust generates arc-type calc-alkaline magmatism that fractionates to generate hydrous, oxidized upper crustal granitoids genetically related to ores (Figure 1.5). In most cases, arc crust is relatively thick, and there is evidence for broadly coeval compressional or transpressional tectonism (Sillitoe, 1972; Tosdal and Richards, 2001).PCDs commonly are centered around small cylindrical porphyry stocks or swarms of dikes that in some cases are demonstrably the cupolas of larger underlying plutons or batholiths. Paragenetic studies suggest that most porphyry deposits are spatially and temporally associated with multiple and superimposed porphyry intrusions and hydrothermal alteration events (e.g., Gustafson et al., 2001; Redmond and Einaudi, 2010). The dimensions and geometries vary widely, due in part to post-ore intrusions, the varied types of host rocks that influence deposit morphology, and especially erosion and post-ore deformation including faulting and tilting (Sillitoe, 2010).The magmatic-hydrothermal evolution of calc-alkaline porphyry copper deposits has widely been studied through the field description of intrusive types, alteration assemblages, vein types, and cross-cutting relationships (e.g., Lowell and Guilbert, 1970; Gustafson and Hunt, 1975; Muntean and Einaudi, 2001; Redmond and Einaudi, 2010).1.7 Research approach and methodologyA combination of both field and laboratory techniques were employed to conduct this research study. Fieldwork comprised two visits to the Los Helados project where mapping and field observations were done. Detailed core logging of selected drill holes was performed in Copiapo city where the company has its core logging facility. Selected rock samples for geochemical and geochronological studies were collected from outcrops that are exposed in the project area and from drill-core. Appendix G shows a table and a figure with the location of the drillholes, azimuth, dip and depth.The study is also supported by laboratory-techniques including petrography (thin-sections and polished thin-sections), geochronology, whole-rock geochemistry, short-wave infrared spectroscopy (SWIR), and X-ray diffraction (XRD) methods.12Figure 1.4: Worldwide locations of porphyry Cu systems cited as examples of features discussed in the text along with five additional giant examples. The principal deposit type(s), contained metals, and age are also indicated (modified after Sillitoe, 2010)131.7.1 Detailed drill logs and mappingMapping and drill core logging methodology for this research was based on a slightly modified Anaconda method (Einaudi, 1997). Twelve complete drill holes and numerous intercepts were logged totaling more than 15000 m (Appendix F shows an example of the drill hole logging). The drill holes selected are part of two representative cross-sections on which this thesis is focused, one with north-south orientation (6864800 N) and other with west-east orientation (442400 W). For this research, the data collection was focused on vein types, geometry, mineral composition, alteration assemblage, and rock type.1.7.2 PetrographyThirty-nine representative samples of hydrothermally-altered and sulfide mineralized rock types were collected for petrographic analysis. Mineral assemblages, hydrothermal alteration and sulfide textures were described by a combination of transmitted and reflected light microscopy. The results are presented in Appendix A1.7.3 Whole-rock geochemistryA set of 27 representative samples were selected and analyzed for whole-rock geochemistry. The analysis included major, trace, and rare earth elements. These samples were analyzed at the Bureau Veritas Minerals (former Acme Analytical Laboratories Ltd.) laboratories, in Vancouver, BC, Canada. A complete list of the samples and procedures is presented in Appendix B.1.7.4 GeochronologyNew U-Pb TIMS zircon dates for porphyritic rocks from Los Helados are presented in order to constrain the timing of the Miocene porphyry intrusions. Additionally, a gabbro-diorite body was dated to determine the possible relationship with the Miocene system. For this thesis, a total of five zircon U-Pb ages were obtained by ID-TIMS: four for Miocene porphyries and one for the gabbro-diorite.All radiometric age dating process was performed at Pacific Centre for Isotopic and Geochemical Research (PCIGR) of the Earth, Ocean and Atmospheric Sciences (EOAS), of The University of British Columbia (UBC). The zircon grains were separated under standard mineral separation procedures, selecting between five and eight crack- and inclusion-free grains, which were chemically 14abraded, dissolved and homogenized with an isotope tracer (EARTHTIME ET535), to be finally thermally ionized, obtaining the isotopic ratios that can be used to calculate the Concordia diagrams and subsequent ages, a process that was performed with the Isoplot software (Ludwig, 2003). The emplacement age of a magmatic intrusion is best approximated by the youngest ID-TIMS age measured from a population of these zircon grains. The results are presented in Appendix C.1.7.5 Short-wave infrared spectroscopy (SWIR)Spectroscopic data were collected (by the author) for 600 samples using an Analytical Spectral Devices, Inc. TerraSpec™ short-wave infrared (SWIR) spectroscopic mineral analyzer. The samples span a vertical range from 0 to more than 1,300 meters below surface. The spectra were measured by placing rock-chips from diamond drill core above a light source for approx. 30 - 60 seconds. The light source was calibrated with a white plate standard approximately every 20 samples. Raw spectra were imported into The Spectral Geologist (TSG) v.7.0.1 software™ for viewing and extraction of numeric parameters such as the wavelength, width and depth of specific absorption features. Particularly important was the measurement of the absorption feature around 2,200 nm wavelength, which was extracted to investigate the properties of white micas.All mineral identification made by TSG was cross-checked manually by visual comparison with standard patterns. Identified minerals and exported wavelength information are presented in Appendix D.1.7.6 X-ray diffraction (XRD)X-Ray Diffraction (XRD) data collected by the author was used as support for petrography, short-wave Infrared spectroscopy results, and alteration assemblages. Additional XRD analyses were conducted on white micas recognized as sericite. XRD was conducted using a standard Siemens (Bruker) D5000 Bragg- Brentano diffractometer at the Department of Earth, Ocean and Ocean Sciences (EOAS), of The University of British Columbia (UBC), at Vancouver, BC, Canada. The diffraction spectra of the samples were compared to ICDD databases found in the EVA software in order to identify alteration minerals within each analyzed sample. The results are included in Appendix E.15Chapter 2. Geological framework2.1 Geological settingThe Andes Cordillera between 26º and 29º south latitude is characterized by Paleozoic to Cenozoic outcrops, arranged in blocks of horst and graben type (Davidson and Mpodozis, 1991) elongated in NE / SW and N / S direction and limited by regional inverse faults of NNE / SSW orientation (Jensen, 1976, Davidson and Mpodozis., 1991, Vila and Sillitoe, 1991; Mpodozis et al., 1995). This segment coincides with the current transitional zone between the Central Volcanic Zone (15º-28º South latitude) and the Flat Slab zone without volcanism (Barazangi and Isacks 1976, Bevis and Isacks, 1984, Sillitoe, 1991).Between 26º and 28º S, most of the Oligocene-Miocene magmatic-hydrothermal centers are hosted in Paleozoic and Mesozoic volcanic basement. This is known as the Maricunga belt (see section 1.4) and was studied by Segerstrom (1968); Mercado (1982); Villa y Sillitoe (1991); Mpodozis (1995); Camus (2003);  Davidson y Mpodozis (1991). South of the 28 °S, the granitic basement increases its area considerably and becomes the main host rock for the hydrothermal centers (Jensen 1976, and Martinez et al., 2015)The late Paleozoic to Triassic igneous units are the host rocks of Los Helados porphyry Cu-Au deposit. These rocks are known by a variety of names along the Andes of northern Chile and the Argentinean Frontal Cordillera. The most accepted name was giving by Stipanicic et al. (1968) who employed the name “Choiyoi Group” for volcanic rocks attributed to the Permian to Triassic outcropping in the Argentinean Cordillera, and this name has been widely used to refer to ʻPermo-Triassicʼ magmatism in both countries. The Choiyoi igneous province consists of volcano-plutonic complexes (Kay et al., 1988; Llambías et al., 1993; Llambías and Sato, 1995) that cover an estimated area of ~500,000 km2, which extends for about 2,500 km, from the Collahuasi area in northern Chile (20°30’S) to Neuquén and the northern Patagonian Andes of southern Argentina (44°S).In the project area rocks from the Choyoi Group are represented by the igneous unit known as the Montosa-El Potro plutonic complex (Mpodozis and Kay, 1990)). Permo-Triassic units are intruded by a series of andesitic dikes at a regional scale and by a Gabbro-Dioritic unit in the northern part of the deposit.16Figure 2.1: Lithological map of Los Helados porphyry Cu-Au deposit Four Miocene porphyry intrusions and two different hydrothermal breccias were documented during the surface mapping and core logging. Surface mapping was done using the top-of-drill hole lithologies as there is little surface exposure of bedrock at the base of the glacial valley. Figure 2.1 (surface map) shows that a unit mapped as a Quartz Feldspar Porphyry has a top-of-bedrock extent of about 400 x 500 m. The Matrix Rich Breccia body is at least 400 x 400 m at surface. Intruding the previous two units are Bimodal Plagioclase Porphyry dikes of 2 to 10 m width, and with a dominant 15° strike.17Figure 2.2. E-W cross-section (line 6864800 E) showing lithology in depth at the Los Helados porphyry Cu-Au deposit (see figure 2.1)The units that do not outcrop are shown in the cross-section (Figure 2.2 and Figure 2.3). The Fine Grained Plagioclase Crowded Porphyry forms dikes of 200 to 300 m deeper in the system and becomes narrower shallower while the Biotite Plagioclase Porphyry forms smaller dikes of about 10 m width. The Cement Rich Breccia forms an elongated body that intrudes the Matrix Rich Breccia.18Figure 2.3: N-S cross-section  (line 443400 N) showing lithology in depth at the Los Helados porphyry Cu-Au deposit (see Figure 2.1).192.2  Lithology2.2.1 Late Paleozoic to Triassic basement rocks (Permo-Triassic suite) 2.2.1.1GraniteThe oldest rocks documented are granites that can be correlated whit the Montosa-El Potro batholith. These rocks cover a large area which exceeds the mapped area (Figure 2.1). They are predominantly granite and granodiorite with a reddish color and a coarse granular texture formed by quartz, plagioclase, k-feldspar and biotite (Figure 2.4). In thin-section (sample AG0023), these rocks exhibit a medium to coarse-grained phaneritic texture which includes euhedral k-feldspar and plagioclase up to 8 mm, granular quartz, euhedral biotite and subhedral clinopyroxene as the main phases.Figure 2.4: Photographs of the Granite in outcrop and drill core. A) Andesite dike is cutting fresh granite (441100 E-6864760 N-UTM-19S). B) LHDH66-47 m. Fresh granite. C) LHDH28-38 m. Granite with hematite oxidized mafic minerals. D) LHDH29-38 m. Granite with sericitic alteration and disseminated pyrite20The age of this unit was assigned to Permian-Triassic by Mpodozis and Kay (1990). New geochronological U-Pb data (Martinez. F et al., 2015) corroborate this age between upper Permian- Lower Triassic (265-245 Ma).2.2.1.2 Feldspar Phyric RhyodacitesThis unit occupies the central and northeastern parts of the deposit. The body of this unit has an orientation of N-NE (Figures 2.1-2.2-2.3). The contact with the Granite is intrusive. This type of contact is evidenced in the drill-core since the surface outcrops are altered or covered.In thin section, the Feldspar Phyric Rhyodacites (FPR) contain approximately 30-35 % phenocrysts set in a fine-grained light grey groundmass consisting of quartz and anhedral plagioclase. The phenocryst assemblage consists of plagioclase (25-30%) up to 2.5 mm diameter and quartz (<10%). Examples of this porphyry can found in appendix A (samples AG0001, AG0003, AG0007, AG0009, AG0011, AG0012, AG0027, AG0028, AG0029)Based on cross-cutting relationships with younger lithologies, particularly the andesite dikes described below, this unit is inferred to belong to the Permo-Triassic suite.2.2.1.3 Andesite dikesAn array of dikes that strike NNE and have a steep westward dip cut the granite, particularly on the eastern side of the deposit area (Figure 2.1). Andesite dikes intrude granites and Feldspar Phyric Rhyodacites (see figure 2.4A). The width of the dikes varies from 30 cm to 7 m.  In hand sample, they are aphanitic to finely porphyritic texture with plagioclase up to 1.5 mm set in an aphanitic greenish groundmass.2.2.1.4 Gabbro-DioriteThis unit forms a stock located 500 m north of the deposit and also an array of N-NE trending dikes that crop out on the northern side of the deposit (Figure 2.1). This unit was documented intruding Granites and Feldspar Phyric Rhyodacites. In the E-W cross-section, this unit forms a sill on the west side of the deposit (Figure 2.2). The upper contact against the Feldspar Phyric Rhyodacite was documented at 600 m below surface in drill holes LHDH71 and LHDH61 while the lower contact was documented at 940 m below surface in drill hole LHDH71. The drill hole LHDH61 ends at 1253 m within Gabbro-Diorite with an unknown depth of the lower contact.21In thin section (samples AG0014, AG0015, AG0016, AG0018, AG0026) this unit presents a medium-grained phaneritic texture containing 70 % euhedral plagioclase, 10 % subhedral biotite, 5% amphibole, 5 % pyroxene, 5% epidote and 5% quartz (Figure 2.6A). Apatite is present as an accessory mineral. Opaque minerals are represented by magnetite.One sample was taken for U-Pb geochronology (sample AG0026), where a CA-ID-TIMS on five zircons gave a concordant age of 232+/- 0.15 Ma for this rock unit (Figure 2.7). Figure 2.5: Photographs and microphotographs illustrating the aspect of Feldspar Phyric Rhyodacites in drill core samples and outcrops. A) LHDH71- 20 m. Pyrite vein is cutting the sample. B) LHDH13- 347 m. Phenocrysts of plagioclase up to 2.5 mm. C)- D) LHDH28- 90 m (sample AG0028). Microphotographs taken under plane-polarized light (C) and under cross-polarized light (D) showing feldspars altered to sericite.22Figure 2.6: Gabbro-Diorite (sample AG 0026, 443208E-6865700N-UTM-19S). A) Fresh outcrop. B-C) Thin section from fresh outcrop taken under cross-polarized light and parallel light, respectively.Figure 2.7: 206PB/238U vs. 207Pb/235U Concordia plots and weighted mean dates of Gabbro-Diorite (sample AG 0026, 443208E- 6865700N-UTM-19S).232.2.2 Miocene Porphyry Intrusions and BrecciasMultiple intrusion and brecciation events occurred during the late Miocene in the Los Helados area. At least four porphyry and two breccia units can be distinguished on the basis of their texture, phenocryst abundances, degree of alteration, grades of mineralization and vein content. They have distinctive timing relationships relative to the main mineralization event. The earliest intrusion, the Quartz Feldspar Porphyry, is a pre-mineralization intrusion. The second (the Fine Grained Plagioclase Crowded Porphyry) and third intrusions (Bimodal Plagioclase Porphyry) are “inter- mineral” and are each associated with an event of brecciation and mineralization. The last intrusion, the Biotite Plagioclase Porphyry, was emplaced “post-mineral” relative timing. These porphyries and breccia units are described in the following sections in order of relative age, from oldest to youngest. Breccias are described on the basis of their components (clasts, matrix and cement) following the classification scheme proposed by Davies et al. (2008). The matrix is the fine-grained clastic component (less than 2mm) that occurs between the clasts. The cement is the crystalline component that may precipitate from an aqueous fluid or from magma. When precipitated from an aqueous fluid the cement includes ore minerals (chalcopyrite-bornite) and/or gangue minerals (tourmaline- quartz-pyrite-gypsum-anhydrite); when precipitated from magma, the cement may be crystalline igneous rock (diorite- or tonalite-cemented breccia).Clasts are the fragments of pre-existing rocks that are incorporated into a breccia. They are described in terms of shape (angular, sub-angular, or rounded) which relates to the energy levels of the breccias in which they are included. Angular clasts are evidence of low energy whereas rounded clasts indicate a high energy environment. Clast content is divided into monomictic (a single rock type as clasts) and polymictic (multiple rocks types as clasts). In general, monomictic breccias indicate limited clast transport, and therefore low energy environments. On the other hand, polymictic breccias are indicative of sampling of various litho-types and clast transportation, and therefore higher energy breccia environments. A single breccia body may change from polymictic to monomictic vertically through the course of its emplacement and from its central part to its margins. It should be noted that intense alteration may obscure the textural characteristics of the clasts, making it difficult to distinguish between lithologies.The following tables (Table 2.1 and 2.2) summarize the main characteristics of the intrusions and breccias described in the Los Helados area.24Abbreviations: Miocene intrusives: BPP: Biotite Plagioclase Porphyry; BiPP: Bimodal Plagioclase Porphyry; FGPCP; Fine Grained Plagioclase Crowded Porphyry; QFP: Quartz Feldspar Porphyry. Minerals: Anhy: anhydrite; Bio: biotite; Cpy: chalcopyrite; Cu: copper; Gyp: gypsum; Qz: quartz; Mg: magnetite; Plag: plagioclase; Ser: sericite. Abbreviations: MRBX: Matrix Rich Breccia; CBX: Cement Rich Breccia; GRN: Granite, FPR: Feldspar Phyric Rhyodacites, AND: Andesites, GA/DIO:Gabbro-Diorite. Minerals: Anhy: anhydrite; Bio: biotite; Cpy: chalcopyrite; Gyp: gypsum; Qz: quartz; Mg: magnetite.Code Internal OrganizationType of clasts Matrix %Cement  %Type of cementAlterationMatrix rich MRBXMonomictic, clast and matrix supportedFPR 20-30 <5 Cpy Py  Anhy  Chlorite alteration patches  at mid depth and strong pervasive Sericite alteration at shallower levelsPolymictic.  clast and matrix supportedFPR-QFP- FGPCP DIO-GRN20-30 <5 Cpy Py  AnhyK-feldspar at depth. Chlorite alteration patches  at mid depthHydrothermal cemented brecciaCBXMonomictic.  Jigsaw-fit,    Clast-supportedFPR-GRN-AND<5 >2-25 Py Gyp Tour Strong pervasive Sericite alterationMonomictic and polymictic, clast and matrix supportedFPR-GRN-AND-DIO-QFP-FGPCP<10 >2-25Mg Bio Anhy Cpy  PySericit alteration in the shallower levels. Chlorite-sericite alteration in the intermediate zone.  K-feldspar and biotite at depth. Table 2.1: Characteristics of the Miocene intrusions in the Los Helados deposit area.  Table 2.2: Characteristics of the Miocene hydrothermal breccias in the Los Helados area.CodePhenocryst/ groundmassPhenocryst assemblageGroundmass assemblageObservations Alteration VeinsBPP 45/55 Plag >Bio Plag Qz  Found at 600 m and deeper below surface and not outcropping.  Most abundant on the west side of the system but overall the least volumetrically important porphyry.   Weak sericitePy GypBiPP 35/65 Plag  Plag  Qz Dikes are found at all depths and at surface. Most abundant on the east side   Weak sericiteQz Py GypFG-PCP50/50 Plag  Plag  QzForms a stock at the root of the system and is present as dikes and as clasts in the MRBXK-feldsparQz  Anhy Py Mg Cpy QFP 35/65 Plag > Qz Plag QzCropping out in the south-east sector and present as a breccia clast.  K-feldspar and sericiteMg Qz Cpy252.2.2.1 Quartz Feldspar PorphyryThe Quartz Feldspar Porphyry unit (QFP) was mapped in the southeastern part of the project area mostly at exposures in road cuts and drill platforms and also in drill holes LHDH01, LHDH02, LHDH42, LHDH71, and LHDH72 (Figures 2.1 and 2.2). The outcrops on the southeastern slope indicate a NNE strike to the QFP intrusions. In drillholes, the contacts with the other units are obscured due to intense alteration. Clasts of this unit are visible in the breccias.In thin section (AG0005, AG0022), the QFP intrusion contains approximately 30-35% phenocrysts in a fine-grained light grey matrix of quartz and plagioclase (Figure.2.8). The phenocryst assemblage is composed of plagioclase (20-25%) and quartz (10-15%). Plagioclase crystals are subhedral and vary between 0.5 mm and 2.5mm. Quartz occurs as rounded anhedral grains with sizes between 0.03 mm and 3 mm. The presence of 10 to 15 % quartz grains is key for differentiating this unit from the Permo- Triassic Feldspar Phyric Rhyodacites where these rocks are intensely altered.A CA-ID-TIMS U-Pb zircon analysis gave a 13.97+/-0.10 Ma for this unit (sample AG129, Figure 2.9).Figure 2.8: Quartz Feldspar Porphyry A) Sample from outcrop (sample AG129, 442702E-6864538N, UTM-19S). B) Sample from outcrop with sericitic alteration (sample AG130, 442705E-6864538N-UTM-19S). (C-D) Microphotographs from B taken under plane-polarized light (C) and under cross-polarized light (D).26 Figure 2.9: 206Pb/238U vs. 207Pb/235U Concordia plots and weighted mean dates of QFP. (sampe AG129, 442702E-6864538N- UTM-19S)2.2.2.2 Fine Grained Plagioclase Crowded PorphyryThe Fine Grained Plagioclase Crowded Porphyry (FGPCP) does not crop out but has been intercepted in several drill holes (LHDH50, LHDH27, LHDH26, LHDH24, LHDH55, LHDH1, and LHDH66) (Figure 2.2 and Figure 2.3); it is also included as clasts in breccias. The east-west cross-section drawn in Figure 2.2 shows that this unit forms two finger-like intrusions that possibly coalesce at depth.In thin sections (samples AG0008, AG0019), it contains between 50 to 55 % phenocrysts in a fine-grained light grey matrix of quartz and plagioclase. The phenocryst assemblage is composed of euhedral/subhedral plagioclase up to 2 mm (45 %), quartz up to 1.5 mm (5%). The groundmass is composed of fine-grained microcrystalline quartz and plagioclase (Figure 2.10).A CA-ID-TIMS U-Pb zircon analysis gave a 13.50+/-0.32 Ma for this unit (Sample AG0012, LHDH21: 554 m, Figure 2.11). Please note that a xenocrystic grain with an age of 27.80 +/-0.29 was analyzed from the sample. 27 Figure 2.10: Photos and thin sections from Fine Grained Plagioclase Crowded Porphyry. All photos present potassium feldpar replacement. A) LHDH72- 806. Early quartz-biotite veins are being cut by quartz vein. B) LHDH50 1210. Wavy quartz vein is cut by quartz and quartz with potassium feldspar alteration halo. C) LHDH50 1200 Early quartz veins with greenish alteration halo are being cut by quartz and anhydrite veins. (D-E) Microphotographs taken under plane-polarized light (D) and under cross- polarized light (E) (sample AG0019).282.2.2.3 Matrix Rich BrecciaThe Matrix Rich Breccia has a surface extent of at least 400 x 400 m (Figure 2.1). The two sections drawn (Figures 2.2 and Figure 2.3) show a breccia body that is 900 x 600 m at depth and elongated along a north-south axis.The contacts are indistinct due to the intense overprinting alteration. In places it is challenging to separate the monomictic portions of the breccia margin from coherent rock of the same lithology as the clasts. The upper contact with the Permo-Triassic Feldspar Phyric Rhyodacite is inferred where truncated veins are no longer present.The Matrix Rich Breccia is characterized by the abundant matrix component (20-30%) derived from the surrounding units with less than 5 % hydrothermal cement (quartz- pyrite-chalcopyrite- anhydrite; Figure 2.12 and samples AG206, AG208, AG210, AG211 in appendix A). It can be divided into monomictic and polymictic domains. The former was documented from the contact with the Feldspar Phyric Rhyodacite to ~600 m below surface. It is clast-supported and dominated by angular/sub-angular clasts of Feldspar Phyric Rhyodacite. When below 600 m depth, the breccia Figure 2.11: 206Pb/238U vs. 207Pb/235U Concordia plot of FGPCP (Sample AG0012, LHDH21: 554 m).29Figure 2.12: Photograph of the Matrix Rich breccia. A) LHDH58-440 m, 0.41% Cu. granite and undifferentiated rounded clasts cut by a quartz-chalcopyrite vein. B) LHDH44-822 m, 0.32% Cu. Matrix Rich Breccia with large rounded clast of biotitized Gabbro-Diorite. C)LHDH62- 1046 m, 0.52% Cu. Matrix Rich Breccia showing clast andesite and undifferentiated. Quartz vein cut the sample. D) LHDH43-828 m, 0.43 % Cu. Rounded granite containing pre-brecciation vein fragment.30is polymictic where the dominant clast composition reflects the nearby host rocks. The base of this polymictic breccia contains clasts of Quartz Feldspar Porphyry, Feldspar Phyric Rhyodacite, Diorite, Granite and Fine Grained Plagioclase Crowded Porphyry. The abundance of Fine Grained Plagioclase Crowded Porphyry is high at the bottom where brecciated clasts and juvenile clasts are part of the Matrix Rich Breccia and this decreases upward. The texture of the breccia is also a function of the location within the breccia body. The central part is matrix-supported with subangular to rounded clasts whereas the lateral areas are clast-supported with angular clasts.2.2.2.4 Cement Rich BrecciaIn the east-west section (Figure 2.2), it occupies the central and eastern parts of the system from 1000 m (LHDH27) to 80 m depth (LHDH01). The documented relationships in the cross-section show that this breccia body forms an irregular pipe that dips to the west. It intrudes the Fine Grained Plagioclase Crowded Porphyry (FGPCP) at depth and then follows the contact between it and the earlier Matrix Rich Breccia. The width of this breccia ranges between 50 m and 200 m in the east-west section logged. The contacts with the host rocks are diffuse as it changes gradually from breccia to stockwork.Clast content and distribution within the Cement Rich Breccia (CBX) is also influenced by the pre- existing Matrix Rich Breccia. The CBX intruded the Matrix Rich Breccia, the clast composition of the two breccias follow the same distribution. The base is polymictic (Feldspar Phyric Rhyodacite, Gabbro-Diorite, Granite, Quartz Feldspar Porphyry, Bimodal Plagioclase Porphyry and Fine Grained Plagioclase Crowded Porphyry) with angular to sub-angular clasts while the top is monomictic in composition (Feldspar Phyric Rhyodacite) with angular clasts.Clast distribution is dominated by clast-supported and jigsaw-fit textures. Scarce zones of cement-supported breccia were documented. Figures 2.13 and 2.14 illustrates examples of this lithology. This unit contains highly variable proportions of mineral cement which fill the voids and cement the breccia. The cement volume ranges from more than 2 % to 25 % of the rock. The mineralogy of the cement varies with elevation through the breccia body. In the middle and upper levels (from 400 m to the top), the cement is composed by pyrite-gypsum-hematite-tourmaline (Figure 2.14). Below 400 m, breccia has been cemented by biotite-anhydrite-magnetite-chalcopyrite (samples AG200, AG201, AG202, AG203 appendix A)31Figure 2.13: Photos of drillcore showing Cement Rich Breccia examples. A) LHDH24-320 m. 0.53% Cu. Clast supported matrix with magnetite-chalcopyrite cement. B) LHDH27-1070 m. 0.67 % Cu. Cement dominated (magnetite-biotite-chalcopyrite) with matrix breccia. C) LHDH 17-373 m. 0.69 % Cu. Clast supported breccia with magnetite chalcopyrite cement.322.2.2.5  Bimodal Plagioclase PorphyryThe Bimodal Plagioclase Porphyry (BiPP) is represented by a series of outcrops that define dikes with a maximum width of 35 m. The outcrops are located on the southeastern hillside along the platforms access roads (Figure 2.1). Dikes of this unit are also present in drill holes from the central to the eastern part of the system. This porphyry has intrusive contacts with breccias and Feldspar Phyric Rhyodacites and contains xenoliths of Gabbro-Diorites and Andesites (Figure 2.15).Figure 2.14: Photos of drillcore showing Cement Rich Breccia examples A) LHDH30-390 m. 0.56% Cu. Tourmaline- Pyrite-Chalcopyrite cement. B) LHDH40-329 m, 0.9 %Cu. Tourmaline-Pyrite-Chalcopyrite cement. C) LHDH50-92 m. Pyrite-gypsum cement.33Figure 2.15: Bimodal Plagioclase Porphyry (BiPP). A) LHDH48-171 m. BiPP with Andesite xenolith. B) LHDH48-252 m. BiPP with a Gabbro-Diorite xenolith. C)LHDH21-260 m (sample AG0010). Intrusive contact between Cemented Rich Breccia and BiPP. D) LHDH21-260 m (sample AG0010). Microphotograph taken under plane-polarized light. E) LHDH21-260 m (sample AG0010) Microphotograph taken under cross-polarized light.34This unit has a greenish color. In thin section (sample AG0010), it shows porphyritic texture containing 35-40 % of phenocrysts in an aphanitic green-grey groundmass. The phenocryst assemblage is composed of euhedral to subhedral plagioclase with bimodal size distribution. The two dominant sizes are 5 mm and 2.5 mm. Euhedral biotite up to 0.3 mm partially altered to chlorite and sericite gives a greenish color to the rock. The groundmass is aphanitic with quartz and plagioclase (Figure 2.15).A CA-ID-TIMS U-Pb zircon analysis gave a 13.88+/-0.16 Ma for this unit (sample AG127, Figure 2.16). This sample presents an antecryst zircon of 14.47 +/-0.19 Ma. Antecryst refers to those zircon crystals that crystallized from an earlier pulse of magma and which are incorporated in a later pulse (Bacon and Lowenstern, 2005; Charlier et al., 2005; Miller et al., 2007).Figure 2.16: 206Pb/238U vs. 207Pb/235U Concordia plot of BiPP (sample AG127, 442822 E, 6864601 N, UTM, 19S)2.2.2.6 Biotite Plagioclase PorphyryBiotite Plagioclase Porphyry forms dikes that do not crop out. They are found at depths of 600 m and deeper, most commonly in the western side of the mineralized zone (Figure 2.2). These dikes are classified as a late mineral due to the sharp contacts (intrusive contacts), low copper content and weak degrees of alteration. They cut Feldspar Phyric Rhyodacites and breccias.35The dikes have an equigranular to moderately porphyritic texture containing 45 % phenocrysts and 55 % groundmass. The phenocryst assemblage is composed of euhedral plagioclase (35%) up to 5 mm zoned and biotite (5%) up to 3 mm euhedral. The groundmass is aphanitic containing fine quartz and plagioclase (Figure 2.17). Examples of this intrusive are described in appendix A (samples AG0002, AG0013)A CA-ID-TIMS U-Pb zircon analysis gave a 13.75+/-0.13 Ma for this unit (sample AG0013, Figure 2.18). This sample presents antecryst zircon of 14.35 +/-0.2 and 14.23 +/-0.06 Ma.  36Figure 2.17: Photos of Biotite Plagioclase Porphyry. A) LHDH26-990 m. B) LHDH50-1210 m. C) LHDH17-499 m. (D-E) LHDH21-725(sample AG0013). Microphotographs taken under plan-polarized and cross-polarized light 37Figure 2.18: 206Pb/238U vs. 207Pb/235U Concordia plot of BPP (sample AG0013)38Chapter 3. Hydrothermal alteration and mineralization3.1 OverviewIn porphyry systems, the alteration-mineralization zoning sequence typically affects several cubic kilometers of rock (e.g., Lowell and Guilbert, 1970; Beane and Titley, 1981; Sillitoe, 2010). As a final product of the hydrothermal alteration processes, it is common to observe a zoned (vertical and lateral) distribution of the alteration-mineralization products, represented by different mineralogical assemblages (Lowell and Guilbert, 1970). Considering the close relationship of this hydrothermal alteration zoning with the abundance of metals of economic interest, the correct identification of these zones is useful in exploration.At Los Helados, the alteration distribution at surface shows a concentric pattern with intense sericitic alteration in the center. Concentrically and outward the intensity of alteration decreases, passing to weak sericitic alteration and epidote-chlorite. A pyrophyllite-kaolinite alteration zone is documented at higher elevations surrounding sericitic zones (Figures 3.1and 3.2).The strong and weak intensity of the sericitic alteration is centered around the Miocene intrusions and breccias over an area of about 2 x 2 km at surface. The epidote-chlorite alteration affects the Granite and the Gabbro-Diorite units; it decreases in intensity from the center of the system to the borders although it extends beyond the area mapped (Figures 3.3 and 3.4).Vertically, the hydrothermal alteration extends to more than 1100 m depth. The deepest drill holes reach 1100 m below surface and end in potassic alteration (k-feldspar and biotite types) (Figures 3.3 and 3.4). Figure 3.3 and 3.4 shows the distribution of the different alteration types in two cross-sections. To unravel the hydrothermal history and to determine the timing of mineralization, vein types were classified based on their main features, documenting different veins types for each of the Miocene units to identify their different intrusive phases.39 Figure 3.1. Alteration map of the Los Helados porphyry Cu-Au deposit , modified from Devine (2015 ). 40Figure 3.2. Detail of alteration map  in Figure 3.1 modified from Devine, 2015. 41Figure 3.3: E-W cross-section (line 6864800 E) showing the distribution of lithologies and alteration types in depth at the Los Helados porphyry Cu-Au deposit (see Figure 3.2).42 Figure 3.4:  N-S cross-section (line 443400 N) showing the distribution of lithologies and alteration types in depth at the Los Helados porphyry Cu-Au deposit (see Figure 3.2).43 3.2 Alteration assemblages at Los Helados porphyry Cu-Au depositAlteration at the Los Helados porphyry Cu-Au deposit is divided into six types with distinct silicates, sulfides and primary-oxide mineral assemblages (Table 3.1). Preliminary description of mineral alteration assemblages was made by visual examination with hand lens. Laboratory techniques such as petrographic thin sections, Short-Wave Infrared Spectroscopy (SWIR) and X-ray diffraction (XRD) were used for mineral identification purposes to complement alteration assemblages descriptions.A detailed description of the different alteration types at the Los Helados porphyry Cu-Au deposit from oldest and deepest to youngest and highest within the system is presented in the following sections.Abbreviations: Al: albite; Anhy: anhydrite; Bio: biotite; Cpy: chalcopyrite; Chl; chlorite; Dik: dickite; Epi: epidote; Gyp: gypsum; Ill: illite; Kao: kaolinite; Kfs: potassic feldspar; Qz: quartz; Mg: magnetite; Mo: molybdenite; Musc; muscovite; Plag: plagioclase; Py: pyrite; Pyr: pyrophyllite; Tour: tourmaline.Alteration type Sub typeMineral assemblageSulfide associationKey mineralsSubordinate mineralsPyrophyllite-kaolinite Pyr  Kao Qz DikEpidote-chlorite Epi Chl Ser Gyp PySericiticStrong Musc  I Py Qz Hem Gyp Tour Py (-Cpy)Weak Musc  I Py Qz Hem Gyp (-Chl) Py (-Cpy)Sericite-chlorite-magnetite Musc Chl Mg Py Qz Esp Py Cpy Mg MoK-Feldspar Kfs Al Qz Chl Mg Anhy BioMg Cpy Py MoBiotite Bio Al Kfs Chl Mg Anhy 3.2.1 K-feldspar (potassic) alterationThe K-feldspar alteration type was documented in LHDH13 and LHDH24 below 450 m from surface; it becomes progressively more widespread with depth (Figure 3.3). This alteration continues beyond currently drilled depths. Potassium feldspar, albite, quartz and subordinate minerals (magnetite, chlorite, anhydrite and biotite) typically occur pervasively and also as quartz Table 3.1: Hydrothermal alteration mineral assemblages documented at Los Helados.44vein alteration halos. The potassium feldspar replacement of plagioclase is commonly seen in breccia- clasts as well as in the Quartz Plagioclase Porphyry, the Feldspar Phyric Rhyodacites, and in the Fine Grained Plagioclase Crowded Porphyry. The Fine Grained Plagioclase Crowded Porphyry shows a pervasive replacement as well as alteration halos to quartz veins. In hand sample, this alteration appears as either pinkish-colored but also in places with a white-color (the presence of potassium feldspar in the white-colored sections was confirmed by cobalt nitrite staining and Figure 3.5: Drill core sample pictures and photomicrographs showing characteristics of the K-feldspar (potassic) alteration at the Los Helados porphyry Cu-Au deposit. A) LHDH24-482 m. Pervasive replacement of plagioclase by K-feldspar (pink). B) LHDH24-488 m K-feldspar alteration halos. C) LHDH21-1335 m. Alteration in vein halo and groundmass. D) LHDH21-1335 m. K -feldspar alteration on Matrix Rich Breccia. Note K-feldspar here is white (confirmed by cobalt nitrite staining, see appendix A, sample AG217)). The left side of the photo shows a sharp contact with the biotitized Gabbro-Diorite. E-F) LHDH21-1399 m (samlpe AG0018). Microphotograph and drill core sample picture of the biotitized Gabbro-Diorite. Hand sample shows a quartz-anhydrite vein. Abbreviations: Al: albite; Biot: biotite; Kfs: potassic feldspar; Qz: quartz;45petrography (see appendix A, sample AG217). Figure 3.5 shows examples of K-feldspar alteration in drill-core samples. This zone is characterized by multi-generational quartz veins as well as quartz-chalcopyrite, magnetite and anhydrite veins. It also hosts the highest copper grades, due to the presence of veins and dissemination and breccia cement of chalcopyrite. 3.2.2 Biotite (potassic) alterationThe biotite alteration type is well represented in the Gabbro-Diorite where potassic alteration is observed as mafic minerals altered to biotite and plagioclase altered to albite and k-feldspar (Figure 3.5D). This alteration is closely related to the K-feldspar (potassic) alteration described above, is similar in relative timing and spatial distribution but restricted to mafic lithologies. It was also documented as biotite cement associated with the cement-rich breccia below 700 m below surface. Anhydrite, magnetite and chlorite are present as subordinate minerals. 3.2.3 Sericite- magnetite -chlorite alterationThis alteration zone occurs in the transition between the potassic and sericitic zones and occupies the upper part of the main copper ore zones (Figures 3.3 and 3.4). Sericite, chlorite, and magnetite characterize the primary mineral assemblage while specular hematite coexists as a subordinate mineral phase. Sericite refers to a field term that includes fine-grained white micas (phengite, muscovite, paragonite, and illite). In Los Helados the most widespread white mica is muscovite as was evidenced by SWIR characterization and core logging description.This alteration is characterized by partial to complete transformation of mafic minerals to chlorite and plagioclase to white micas (corroborated by portable short wave infrared spectrometer and X-ray diffraction, see white micas section). In hand sample, it appears as a pale green alteration assemblage of muscovite and chlorite (Figure 3.6). The white micas that replace plagioclase are a whitish color in the transition to the sericitic zone, where it becomes increasingly pale-green downward into the sericite-chlorite-magnetite zone. Muscovite is also abundant in selvages along millimeter to centimeter-scale quartz-pyrite veins. Chlorite occurs mostly as irregular patches replacing hydrothermal biotite in the breccias and replacing magmatic biotite in the intrusive rocks and granite in areas near a breccia body. Magnetite and hematite coexist as disseminated grains and veins.46Figure 3.6: Drill core sample pictures and photomicrographs showing sericite-chlorite-magnetite alteration assemblages at the Los Helados porphyry Cu-Au deposit. A) LHDH21-387 m. Feldspars are replaced by sericite, and mafic minerals are replaced by chlorite and magnetite. Late pyrite vein with sericitic halo is cutting the sample. B) LHDH12-545 m. Feldspars are replaced by sericite, and mafic minerals are replaced by chlorite and magnetite. Chalcopyrite veins are cutting an older quartz vein. C) LHDH24-380 m (sample AG210). Matrix Rich Breccia with magnetite-hematite-pyrite-chalcopyrite cement. D) LHDH24-380 m (sample AG210),. Photomicrographs under cross-polarized transmitted light. Abbreviations: Cpy: chalcopyrite; Chl: chlorite; Mg: magnetite; Qz: quartz; Py: pyrite; Ser: sericite.473.2.4 Sericite alterationTwo sub-types of sericitic alteration associated with the alteration intensity were recognized at the Los Helados porphyry Cu-Au deposit: In the strong sericitic alteration all feldspar has been completely replaced by white micas, while in weak sericitic alteration some plagioclase and potassium feldspar crystals remain (Figure 3.7). Strong-sericitic alteration is texturally destructive. Quartz (50-70 % vol), white micas (25-35% vol) and pyrite (5% vol) are the key minerals. Tourmaline and gypsum are found in veins and as a breccia cement. Hematite is present as a primary mineral and also altering magnetite. The replacement of the plagioclase by sericite is complete in the core of the system and decreases outward. The pervasive alteration occurs near to the breccia and affects the breccias, Feldspar Phyric Rhyodacites, and the proximal parts of the Granite (Figure 3.7).The weak-sericitic alteration is represented by a weak-moderate replacement of plagioclase by white micas and a weak chloritization of the mafic minerals (biotites). In this case, the texture of the primary rock is preserved (Figure 3.7 E-F)3.2.5 Epidote-chlorite alterationThe epidote-chlorite alteration at the Los Helados porphyry Cu-Au deposit forms a ring around the Sericitic and Pyrophyllite-kaolinite alterations (Figure 3.1) in which the outer edge extends beyond the mapped area. This alteration type affects the Granite and the Gabbro-Diorite units, the alteration intensity decreases from the center of the system to the borders.  It is mostly associated with weakly altered rocks around the periphery of the system, with epidote and chlorite replacing primary mafic minerals and with relicts of plagioclase and potassium feldspar. The rock texture is preserved and mafic phases are partially replaced by chlorite.3.2.6 Pyrophyllite-kaolinite alterationThe pyrophyllite-kaolinite alteration at the Los Helados porphyry Cu-Au deposit was identified in two areas during field mapping: One is located close to the main breccia body, on the northwestern edge (Figure 3.1), and other about 1 km to the south of the main breccia body in a topographically elevated area (about 500 m above the valley floor). This alteration type is characterized by the presence of pyrophyllite and kaolinite (-alunite) replacing feldspar and residual quartz, obliterating the original texture of the rock. 48Figure 3.7: Drill core and outcrop photographs and photomicrographs illustrating the characteristics of the sericitic alteration at the Los Helados porphyry Cu-Au deposit. A) LHDH50-92 m. (sample AG201). Jigsaw breccia cemented by pyrite and quartz. Angular clasts of Feldspar Phyric Rhyodacite are strongly altered. Feldspars are completely altered to sericite. B) LHDH50-92 m. (sample AG201), photomicrograph under cross-polarized transmitted light. Angular clasts completely altered to quartz and sericite cemented by pyrite. C) Outcrop of Feldspar Phyric Rhyodacite (442613E-6864811N-UTM-19S) with intense sericitic alteration cut by a stockwork of quartz veins. D) Granite with intense sericitic alteration cut by quartz and pyrite veins. E). Outcrop of the Bimodal Plagioclase Porphyry (442490E-6864597N-UTM-19S) showing an example of weak sericitic alteration F) LHDH21-260 m. (sample AG0010). Bimodal Plagioclase Porphyry. photomicrographs taken under cross-polarized transmitted light, showing plagioclases partially altered to sericite. Abbreviations; Qz: quartz; Py: pyrite.3.3 Alteration zoning at Los Helados porphyry Cu-Au depositBased on drill core observations and the vertical alteration types distribution (Figures 3.3 and 3.4) at the Los Helados porphyry Cu-Au deposit, some interesting aspects of the deposit-scale alteration zoning patterns are worth to de mentioned. 49Plagioclase replacement is more intense in the center of the system and decreases outwards, towards the margins, from strong-sericitic to weak-sericitic. In addition, the boundary between sericitic and potassic/sericite-chlorite-magnetite alteration has an inverted U shape.K-feldspar-rich alteration is widely developed in the Matrix Rich Breccia and Cement Rich Breccia as well as in the Fine Grained Plagioclase Crowded Porphyry. The biotite-rich alteration dominates the Gabbro-Diorite, as confirmed by the presence of diorites with biotite alteration on the east side of the main breccia body (Figure 3.3).The sericite-chlorite-magnetite (SCM) alteration is overprinted the K-feldspar alteration. It is spatially related to the upper contact of the Matrix rich breccia and the Feldspar Phyric Rhyodacites. This alteration forms a domain about 200 meters wide that flanks the sides of the Matrix Rich Breccia from 300 to 600 m in depth below the surface. The downward change from SCM to K-feldspar alteration is gradual and represented by the decrease of disseminated magnetite and chlorite and an increase of the K-feldspar.3.4 The white micas at the Los Helados porphyry Cu-Au depositWhite micas are present throughout the Los Helados porphyry Cu-Au deposit and are the major contributor to the short- wave infrared spectral responses (SWIR). They were documented especially in the sericite and sericite-chlorite-magnetite alteration types but also in the k-feldspar and biotite alteration zones. The distribution of sericite and the solid solution variations within it potentially provide a valuable vectoring tool (Halley et al., 2015).This section describes the application of SWIR spectroscopy to characterize the white micas across the deposit. 3.4.1 Short-wave infrared (SWIR) spectroscopy Numerous minerals within porphyry systems can be identified and mapped with SWIR, many of them present within the Los Helados porphyry Cu-Au deposit alteration system, including: white micas (paragonite-muscovite-phengite), chlorite (clinochlore-chlorite-chamosite), kaolinite, alunite, pyrophyllite, amphibole (hornblende and actinolite solid solutions), epidote (epidote to clinozoisite solid solutions), and locally biotite (solid solutions specify).Short-wave infrared spectra record the vibrational energy of molecular bonds within the 400 – 502500 nm region of the electromagnetic spectrum and are plotted as a reflection (percent) versus wavelength (nm). Atoms and molecules absorb energy as a function of their atomic structures. SWIR spectroscopy is particularly sensitive to -OH, -NH4, -CO3 radicals, H2O molecules and cation-OH bonds such as Al- OH, Mg-OH and Fe-OH, which are present in phyllosilicates and clays (Table 3.2). The compositional variations in phyllosilicates can be identified by analyzing the position and shape of the absorption features (Thompson et al., 1999).The characteristic Al-OH absorption feature for white micas and clays is at 2200 nm, whereas for chlorites, it is at 2250 nm (Fe-OH) and 2350 nm (Mg-OH) absorptions (Thompson et al., 1999). Characteristic SWIR absorption features for white micas group minerals (including muscovite, illite, paragonite and phengite; Deer et al., 1992), clays, and chlorite minerals observed at Los Helados  porphyry Cu-Au deposit and the approximate position of their Al-OH absorption feature are summarized in Table 3.3.  3.4.2 SWIR spectroscopy results from Los Helados porphyry Cu-Au depositSix hundred measurements were acquired throughout the study area, in core and outcrop samples. Sample selection focused on drill cores along the two defined cross-sections (Figure 3.3 and 3.4). Samples were analyzed and processed using The Spectral Geologist (TSG) software to characterize mineralogy and extract the positions and depths of spectral absorption features. Follow-up work using X-ray diffraction analyses was conducted on specific samples in order to confirm the reliability of spectral data.Table 3.2: Main absorption features present in phyllosilicates and clays. Modified from Thompson et al., 1999.Position Mechanism Mineral group~1400 OH and water Clays, sulfates, hydroxides, zeolites~1560 NH4 NH4 species~1800 OH Sulfates~1900 Molecular water Smectite~2200 Al-OH Clays, micas~2250 and 2350 Mg-OH Chlorite51Given that in Los Helados area, the porphyry-epithermal system is well preserved, from the argillic lithocap at the shallowest levels to the potassic alteration continuing beneath the 1150 m currently drilled depth, the data obtained from this study provides an excellent opportunity for studying vertical changes in the system behavior and apply them to to the exploration of new areas of interest.Of the 600 samples evaluated, 512 samples indicate the presence of muscovite. The spectral features of both micas are very similar; the only difference is that illite has a deeper H2O absorption feature at 1900nm. It has been demonstrated by Davies et al. (2003) that illite and muscovite cannot be readily distinguished by SWIR spectroscopy. Due to this subtle difference, in this study, both micas are treated as muscovites without differentiating between them.The distribution and composition of chlorite within the Los Helados porphyry Cu-Au deposit sections were also evaluated with the SWIR analysis, but due to its low optical reflectivity, the spectral features were challenging to determine. Moreover, the high concentration of white-micas in the Los Helados system, which have high reflectivity, obscures the chlorite spectral features. X-ray diffraction analysis determined that both muscovite and chlorite coexist in samples from 290 m below surface and deeper, where they occur together within the sericite-chlorite-magnetite alteration domain.Table 3.3: The characteristic features for white mica, clay, and chlorite minerals common to this study and the approximate position of their Al-OH absorption (Thompson et al., 1999).Mineral FormulaCharacteristic SWIR absorption featureWavelength of Al-OH absorption (2200 approx.)Muscovite (KAl2(AlSi3)O10(OH)2)Sharp feature at 1400, 1910, 2200nm.2198-2208 nmParagonite NaAl2Al3O10(OH)2 Similar to muscovite 2185-2193 nmPhengitic muscovite3K(Fe Mg) 0.5Al1.5 Similar to muscovite 2208-2215 nm(Al0.5Si3.5)O10(OH)2Chlorite (Fe, Mg, Al)6(Si, Al)4O10(OH)8 2260, 2350 nm -52The spectra of the white micas, particularly the location of the 2200 nm feature, vary within each alteration type. The variation is related to changes in the chemistry of the white micas (e.g., Cohen, 2011). The ranges determined for each alteration type at the Los Helados porphyry Cu-Au deposit are shown in Table 3.4.For further analysis of the variation SWIR mineral response, the drillhole LHDH24 was selected because it has the most significant number of samples and intersects the main alteration types. The downhole-strip log in Figure 3.8 compares visual observations, copper grade and SWIR results through the drill-hole LHDH24. Color dots represent the value of the 2200 nm absorption feature. Three zones can be distinguished based on the range of variation in the 2200 nm absorption feature (black boxes). The first zone extends from 0 to 330 m below surface (approximately) where values range from 2190 to 2204 nm. This zone coincides with the sericitic and the upper part of the sericite-chlorite-magnetite alteration and involves Granite and Feldspar Phyric Rhyodacite. In the second zone, the absorption values range from 2205 to 2220 nm and extend from 330 to 670 m below surface. The upper limit has a strong lithological control marked by the beginning of the Matrix Rich Breccia. The lower part involves Cement Rich Breccia. It partially covers the sericite- chlorite-magnetite and the upper portion of the k-feldspar alteration. The last zone extends from the 670 m to 940 m below surface where the drillhole intersects the Fine Grained Plagioclase Crowded Porphyry. Cement Rich Breccia and Fine Grained Plagioclase Crowded Porphyry with K-feldspar alteration were documented in this segment. The 2200nm absorption feature ranges between 2202 and 2210. The shift in the 2200 absorption feature with depth is seen in Figure 3.9.Table 3.4: Summary of alteration types, key mineral assemblages, white mica group minerals and range of values of the 2200nm absorption feature at the Los Helados porphyry Cu-Au deposit.Ateration typeKey Mineral assemblageWhite micas2200 absorption featurePyrophyllite-kaolinitepyrophyllite kaolinite  quartzparagonite 2190-2195Epidote-chlorite epidote  chlorite muscoviteStrong Sericiticmuscovite  pyrite quartzmuscovit-paragonite2190- 2204 Weak sericitic muscovite   pyrite quartzmuscovite phengite2204-2210Chloritic -magnetite -sericite chlorite magnetite muscovitemuscovite phengite2205-2220K-Feldspar k-Feldspar albite muscovite 2202-2210 Biotite Biotite albite muscovite53Figure 3.8: The downhole strip log for LHDH24 comparing visual observations, geochemical data (copper and gold grades. The geochemical data is from NGEX), and SWIR results (Appendix D). The black boxes indicate the three zones described in the text. Dots are the value of the 2200 absorption feature; the color of the dot represents the alteration type.54Figure 3.9: SWIR spectra from LHDH24 drill core samples that show the presence of muscovite. With increasing depth, the shape of the spectra changes and the 2200nm feature shifts to vaues  that indicate a more phengitic (Fe-rich) muscovite composition.3.5 Vein paragenesis and timing of hydrothermal mineralization at Los Helados porphyry Cu-Au deposit3.5.1 Vein classificationThe veins have been characterized based on mineral composition, geometry, cross-cutting relationships and in terms of their relative timing to other veins. Eleven distinct vein types have been recognized from all rock units at Los Helados. Table 3.5 summarizes the divisions made and the main features for each vein type.55The veinlet sequence in porphyry Cu deposits, first elaborated by Gustafson and Hunt (1975) at El Salvador, is used here for comparison purposes.3.5.1.1 Early veinsEarly veins are represented at Los Helados porphyry Cu-Au deposit by type 1, 2A, 2B, 2C and 2D (Table 3.5).Type 1: Quartz with sericite-biotite-feldspar-pyrite halo.The earliest veins observed at the Los Helados porphyry Cu-Au deposit correspond to granular quartz veins with biotite-potassium feldspar-pyrite-chalcopyrite halo (vein-type 1). These types of veins were not described by Gustafson and Hunt (1975). Other authors documented these veins at Butte (Meyer, 1965; Brimhall, 1977; Rusk et al., 2008a) and Bingham (Redmond et al.,  Abbreviations: Anhy: anhydrite; Bio: biotite; Cpy: chalcopyrite; Gyp: gypsum; Kfs: potassic feldspar; Qz: quartz; Mg: magnetite; Mo: molybdenite; Py: pyrite; Ser: sericiteCodeGustafson and Hunt (1975)Main mineral associationSubordinate mineralsGeometry Width (mm)Alteration halo  Width (mm)Early1 Qz  straight to slightly wavy1-5Bio Kfs  Py Cpy4-152A A Qz   Cpy wavy 3-25 Kfs 1-32B A Qz  Bio straight to slightly wavy0.3-3 Kfs 2-52C A Qz  Cpy Py Mo straight 5-20  none  2D A Qz  Cpy Py straight 3-7  none               Transitional3 B Qz CpY Py Qzstraight. Central suture 4-15  none  4 B Mg Cpy Qz Py  Anhystraight to slightly wavy1-40  none  5 B Anhy Cpy Qz straight 5-25 none  6 B Py Cpy Gyp straight 3-15  none  7 B Qz Mo PyPy Cpy Gyp Anhystraight 3-10  none  Late 8 D   Qz Py straight 5-20 Ser 5-30Table 3.5: type of veins documented at Los Helados, this table is showing a column for comparison with Gustafson and Hunt (1975).562004). These veins are also known as early dark micaceous (EDM) (Meyer, 1965). The width of the granular quartz infill varies between 1 to 5 mm while the alteration halo increases the width between 4 and 15 mm. The biotite ranges from brown to green with shreddy texture and potassium feldspar is replacing plagioclase. Generally, these veins are straight-walled (Figure 3.10), but in a few samples, undulous vein walls have also been observed. Type 2 (2A-2B-2C-2D): quartz veins with or without potassium feldspar halos.The “A” type (Gustafson and Hunt (1975)) in this thesis are described as type 2 (2A-2B-2C-2D). Type 2A veins are composed of wavy veins with granular quartz with thickness between 3 to 25 mm. These veins were documented only in the Fine Grained Plagioclase Crowded Porphyry. The K-feldspar alteration halo varies between 1 to 3 mm wide and is not always present. This type of vein is mostly sulfide-free; only rare fine chalcopyrite is present (Figure 3.11). Sample AG008-Appendix A- describes an example of this vein type.Type 2B corresponds to thin sinuous granular quartz veins (0.3 to 3 mm) with potassium feldspar alteration halo (2-5 mm). They are commonly found cutting wavy quartz veins (type 2A; Figure 3.11) and only contain scarce fine chalcopyrite.Straight quartz veins (vein types 2C and 2D) are the most abundant at the Los Helados porphyry Cu-Au deposit. They were also documented as truncated veins within the breccias. These granular quartz veins are sulfide free, have straight walls and do not have alteration halo (Table 3.5, Figures 3.11 and 3.12). The  main difference between types 2C and 2D is their thickness. The 2C veins have a thickness of 5-20 mm (sample AG0011, Appendix A), while 2D veins are relatively thinner (3-7 mm) (sample AG0003, Appendix A).3.5.1.2 Transitional VeinsTransitional veins are represented at Los Helados porphyry Cu-Au deposit by the types 3-4-5-6-7 (type “B” veins (Gustafson and Hunt (1975)) (Table 3.5)Type 3: Quartz with central suture of pyrite-chalcopyrite veins.Type 3 veins are granular quartz veins with a central suture of pyrite-chalcopyrite. These straight-walled veins have a thickness between 4 to 15 mm (Figure 3.13). 57Figure 3.10: LHDH 28- 560 m. Cross-cutting relationship in Fine Grained Plagioclase Crowded Porphyry. Numbers refer to the Code in Table 3.5. Abbreviations: Bio: biotite; Cpy: chalcopyrite; Kfs: potassium feldspar; Mo: molybdenite; Py: pyrite; Qz: quartz.Figure 3.11: LHDH50-1222 m. Cross-cutting relationship in Fine Grained Plagioclase Crowded Porphyry. Type 2a vein cut by younger vein types. Vein numbers refer to the codes in Table 3.5. Abbreviations: Kfs: potassium feldspar; Qz: quartz Figure 3.12: LHDH21-285 m. Cross-cutting relationship in Feldspar Phyric Rhyodacite. Numbers refer to the Code in Table 3.5. Abbreviations: Cpy: chalcopyrite; Py: pyrite Qz: quartz.58 Type 4: Magnetite (chalcopyrite-pyrite) veins.Magnetite and chalcopyrite make up a significant component of this vein- type. Other minerals commonly observed include subhedral biotite, hematite, pyrite, granular quartz, and tourmaline. Gangue minerals show a vertical zonation in the deposit. Biotite and anhydrite are common at depth while in the shallower parts pyrite, tourmaline and gypsum make up the major gangue minerals.These veins are commonly straight-walled although some examples have wavy walls (Figure 3.14) (Sample AG205, appendix A). The thickness varies depending on the distance from the main breccia body. Close to the breccia these veins can reach a thickness of 4 cm but they are narrower further away. Type 5: Anhydrite-chalcopyrite veins.Anhydrite-chalcopyrite veins (vein-type 5) are commonly straight-walled but in some cases they show a slight sinuosity (Figure 3.15). The width varies from 5 to 20 mm. These veins were documented with greater abundance in the drillholes LHDH56 and LHDH26 located in the western sector of the section E-W (Figure 3.3).Type 6: Pyrite-chalcopyrite veins.Pyrite-chalcopyrite veins (vein-type 6) have straight walls with a thickness between 3 to 15 mm. Besides the principal minerals (Py-Cpy), they may also contain gypsum, anhydrite and quartz as subordinate minerals (Figures 3.12 and 3.16)  Type 7: Quartz-molybdenite veins.Quartz-molybdenite (-chalcopyrite-pyrite) veins (type 7) have straight walls with a thickness between 3 and 10 mm (Figure 3.10 )3.5.1.3 Late veinsThe latest veins are represented at Los Helados porphyry Cu-Au deposit by the type (type “D” Gustafson and Hunt (1975)) 59Figure 3.14: LHDH72-506 m. Cross-cutting relationship in Matrix Rich Breccia. Numbers refer to the Code in Table 3.5. Abbreviations: Cpy: chalcopyrite; Mg: magnetite; Qz: quartz.Figure 3.15: LHDH24-323 m. Cross-cutting relationship in Feldspar Phyric Rhyodacite. Numbers refer to the Code in Table 3.5. Abbreviations: Anhy: anhydrite; Cpy: chalcopyrite; Py: pyrite; Qz: quartz.Figure 3.13: LHDH 28-775 m. Cross-cutting relationship in Feldspar Phyric Rhyodacite. Numbers refer to the Code in Table 3.5. Abbreviations: Cpy: chalcopyrite; Py: pyrite;  Qz: quartz; Ser: sericite.Figure 3.16: LHDH 13-353 m. Cross-cutting relationships in Bimodal Plagioclase Porphyry. Type 6 vein cuts type 4 vein, and both are cut by late Type 8. Abbreviations: Mg: magnetite; Py: pyrite, Qz: quartz.60Type 8: late pyrite with sericitic alteration halo.All previous sets of veins are cut by late pyrite veins with sericitic alteration halo (type 8). These veins always are straight-walled but vary in thickness in both the vein fill and alteration halo (Figure 3.10 and 3.14). The alteration halo ranges from 5 to 30 mm while the veins range from 5 to 20 mm (sample AG0011, appendix A),.3.5.2 Vein and mineralization Timing Porphyry Cu-related intrusions comprise multiple phases, emplaced immediately before (early-mineral porphyries), during (inter-mineral porphyries), near the end of (late-mineral porphyries), and after (post-mineral porphyries) alteration and mineralization events (Kirkham, 1971; Gustafson, 1978). At the Los Helados porphyry Cu-Au deposit, six episodes of porphyry and breccia intrusions, grouped into early-mineral (Quartz Feldspar Porphyry), inter-mineral (Fine Grained Plagioclase Crowded Porphyry, Matrix rich Breccia, Cement Rich Breccia, Bimodal Plagioclase Porphyry), and late- mineral (Biotite Plagioclase Porphyry), have been identified.To determine the hydrothermal history associated with the different generations of porphyry and breccia intrusion, vein types contained within each group were documented. Cross-cutting relationships between the vein types, vein density and alteration intensity generated during each episode of porphyry and breccia intrusion observed at the Los Helados porphyry Cu-Au deposit are summarized in Figure 3.17.Vein densities are used only for comparison purposes between intrusive phases. At the Los Helados porphyry Cu-Au deposit, vein densities are not strictly associated with copper grade as the majority of copper was introduced during the breccia phases. 3.5.2.1 Veins in late-mineral phases.The Biotite Plagioclase Porphyry (BPP) is the youngest hydrothermal pulse documented at Los Helados. It forms dikes between 2 to 30 m apparent thickness containing 0.2 % Cu (average). The vein density and vein variability are low compared with the older intrusions. Vein densities are low than 4 veins per meters. The only vein-type documented in this rock unit is the pyrite filled veins with white micas halos (type 8). These intrusions present a weak sericitic alteration (Figure 3.17).61Figure 3.17: Schematic crosscutting relationships between the veins and their classification into three distinct intrusive phases at the Los Helados porphyry Cu-Au deposit. The relative timing of alteration types and total vein density are also shown in relation to the vein paragenesis. Vein numbers refer to the codes in Table 3.4. Abbreviations: Miocene intrusives: BPP: Biotite Plagioclase Porphyry; BiPP: Bimodal Plagioclase Porphyry; FGPCP; Fine Grained Plagioclase Crowded Porphyry; QFP: Quartz Feldspar Porphyry. Minerals: Bio: biotite; Chl: chlorite Epi: epidote; Kao: kaolinite; Kfs: potassium feldspar; Mg: magnetite; Pyr: pyrophyllite; Ser: sericite.623.5.2.2 Veins in inter-mineral phasesThe veins that are temporally associated with the inter-mineral porphyries and breccias have the highest density and variability and compose the most important volume of copper in Los Helados. This hydrothermal event also contains significant chalcopyrite disseminations and as a breccia cement. The alteration as well as the veins densities are higher at the beginning of the inter mineral phases and get lower in the younger phases. Vein densities can reach up to 30 veins per meter in the Fine Grained Plagioclase Crowded Porphyry and decrease to values of 10 veins per meter in Bimodal Biotite Porphyry. In the breccia intrusive phases, most of veins documented as clasts correspond to type 2C and 2 D. Figure 3.17 shows that some veins are common to all porphyries and breccias while others were exclusively documented in one porphyry.The earliest veins at Los Helados were documented exclusively in the Fine Grained Plagioclase Crowded Porphyry (FGPCP) (Figure 3.10 and Figure 311). These veins include types 1 (quartz with sericite-biotite-potassium feldspar-pyrite halo), 2A (wavy quartz with a thickness between 3 to 25 mm) and 2B (quartz veins with potassium feldspar alteration halo). Examples of these veins were also documented as truncated veins in the Matrix Rich Breccia. Veins of type 1, 2A and 2B generally occur at depths greater than 800 m below surface, but a few examples of these veins were described in shallower positions, associates with finger-like FGPCP intrusions.The types 2C and 2D veins are volumetrically the most important set of veins and are found at all depths. These quartz-dominated veins containing variable amounts of chalcopyrite and pyrite were observed throughout all inter-mineral lithologies although vein densities are higher in the FGPCP. Cross-cutting relationships demonstrated that existed at least two generations of these veins.The vein types 3, 4, 5, 6 and 7 were documented throughout all inter mineral lithologies. Vein density is higher in the Fine Grained Plagioclase Crowded Porphyry and gets lower in the youngest lithologies. Veins that occur in the late mineral porphyries (types 8) are present within the inter mineral phases. (Figure 3.17). The copper grade of this stage is related to breccia cement and veins 2 (quartz variable amounts of chalcopyrite), 3 (quartz with central suture of pyrite-chalcopyrite), 5 (anhydrite-chalcopyrite), 6 (Pyrite- chalcopyrite) and disseminated chalcopyrite.633.5.2.3 Veins in pre-mineral phasesQuartz Feldspar Porphyry (QFP) represents the first Miocene intrusion. It forms an outcrop of about 500 x 350 m located at south of the main hydrothermal system.Vein densities and type of veins varies depending on where the measurement is done. In the southern part of the outcrop, the veins type documented are 2D (3 mm straight quartz) and 8 (pyrite with sericitic halo) with low density. In the northern exposure of this unit, near the contact with younger porphyry intrusions the copper grade, vein density, and vein types increase. Vein types documented there are the same as in the inter mineral phases although with lower densities than in the inter-mineral porphyries.3.6 Sulfide and Metal Zoning3.6.1 Sulfide zoningFour mineral zones were documented at Los Helados that are based on the presence and relative ratios (not total abundances) of the dominant sulfide species (Figures 3.20-3.21). From top downwards they are pyrite, pyrite-chalcopyrite, chalcopyrite-pyrite and chalcopyrite. This sulfide zonation shows a progressive downward increase in the amount of chalcopyrite relative to pyrite. There is a correlation between changes in sulfide species and the alteration zonation through the system.The pyrite zone is within the sericitic alteration; it occupies the first 20 to 55 meters from the surface in the center of the system (Figure 3.20). Pyrite is present as a primary mineral in veins, dissemination and as a breccia cement. The average size of the pyrite grains is 37 microns (QEMSCAN analysis, NGEX internal report from August 2013). Molybdenite was also documented in quartz-molybdenite veins with an average grain size of 6 microns. Pyrite zone examples are shown in figure 3.18 A-B. In this figure, pyrite constitutes the only mineral and is cementing a jigsaw-fit breccia. Traces of chalcocite and covellite were documented close to the surface in fracture zones during core logging. Copper grades in this zone are lower than 0.1 % Cu. The pyrite-chalcopyrite zone is located below the pyrite zone and the lower limit coincides with the lower limit of the sericitic alteration (Figures 3.20-3.21). Pyrite remains the dominant sulfide, accompanied by chalcopyrite. Both occur as a primary sulfide in veins, dissemination and as a breccia cement. The average grain size of the sulfides is 35 microns for pyrite and 21 microns for 64chalcopyrite (QEMSCAN analysis, NGEX internal report from August 2013). Quartz-molybdenite veins are rare. Copper grades in this zone vary depending on the vertical position. Close to the upper limit with the pyrite zone, the copper grade is close to 0.1 % and increases toward the deepest parts where copper values are up to 0.6 %. An example of the sulfides in the pyrite-chalcopyrite zone is shown in Figure 3.18 C-D The chalcopyrite-pyrite zone includes the sericite-chlorite-magnetite zone, the lower part of the sericitic zone, and k-feldspar and biotite zones (Figures 3.20-3.21). This zone has the same characteristic as the pyrite-chalcopyrite but chalcopyrite is the main sulfide and magnetite is also present. Figure 3.19 A-B illustrates the sulfide assemblage of this zone. Average copper grade in this zone is 0.5 % with local values over 1 %. The chalcopyrite zone is entirely in the k-feldspar and biotite zones. Chalcopyrite represents the main sulfide with an average grain size of 19 microns. It is found in veins, dissemination and as Figure 3.18: Drill core photographs and reflected light photomicrograph illustrating hypogene Cu-Sulfide mineralization in breccias at Los Helados porphyry Cu-Au deposit. (A-B) LHDH50-93 m (sample AG201). Jigsaw breccia cemented by pyrite. (C-D) LHDH13-358 m (sample AG211). Matrix Rich Breccia with acicular crystals of hematite, pyrite, and chalcopyrite. Abbreviations: Cpy: chalcopyrite; Hm: hematite; Py: pyrite.65Figure 3.19: Drill core Photographs and reflected light photomicrograph illustrating hypogene Cu-Sulfide mineralization in breccias in the chalcopyrite-pyrite zone (A-B-C-D) and chalcopyrite zone (E-F) at Los Helados porphyry Cu-Au deposit. (A-B) LHDH30-741 m (sample AG204). Cement rich breccia with chalcopyrite, pyrite, magnetite and hematite cement. (C-D) LHDH50-679 m (sample AG202). Cement Rich Breccia cemented by- chalcopyrite magnetite and less pyrite (E-F) LHDH34-920 m (sample AG200). Vein of chalcopyrite (Vein type 2C) with traces of molybdenite. Abbreviations: Cpy: chalcopyrite; Hm: hematite; Mg: magnetite; Py: pyrite.a breccia cement. Traces of bornite and molybdenite were documented in veins associated with quartz-chalcopyrite. Copper grade in this zones vary depending on the vertical position. Higher copper grades are found in the upper section and following the Cement Rich Breccia. Average copper values in this zone are between 0.5 %Cu with local zones over 1 % Cu. Below 900 m under surface, copper grades decrease to values under 0.35 %. Examples of the sulfides assemblages in this sulfide zone are shown in figure 3.19.  663.6.2 Metal zoning3.6.2.1 Copper distributionTotal copper volume distribution forms, in cross-sections, a different pattern than the sulfide species zonation although both contour lines are entirely below the chalcopyrite-pyrite zone. Copper distribution shows lithological control. The 0.5% copper contour line has a semi-circular shape. It starts at 300 m below surface where it is 300 m wide and continues to 1000 m depth where its width is 800 m. The figure 3.20 shows that the 0.5 % copper contour follows closely the Matrix Rich Breccia contact including the sericite- chlorite-magnetite, the k-feldspar alteration zones and also the deepest parts of the sericite alteration zone.The contour line for copper grades > 0.6 % has an elongate form of 500 m long for 200 m in its widest part and it extends from 350 m to 900 m below surface. Figure 3.20 shows that this is closely related to Cement Rich Breccia body particularly in the area of magnetite-chalcopyrite cement.3.6.2.2 The gold distributionThe gold distribution differs from the copper. Gold grades > 0.25 ppm occur in a semi-circular shape of 400 m for 500 m that starts at surface and is almost entirely in the zone with pyrite as the dominant sulfide.3.6.2.3 SilverSilver distribution shows the same pattern as Copper. The 0.5 % Cu contour coincides with values of 2 ppm Ag. 3.6.2.4  MolybdenumMolybdenite occurs as a trace sulfide in quartz and chalcopyrite veins (Figure 3.19). Molybdenum distribution occurs as local anomalies in Los Helados. and it does not represent an ore mineral. 67Figure 3.20: E-W cross-section (line 6864800 E) showing the distribution of lithologies, alteration types, sulfides zoning and metal zoning in depth at the Los Helados porphyry Cu-Au deposit (see Figure 3.2).68Figure 3.21: N-S cross-section illustrating lithology, alteration, sulfides zoning, and metal zoning in depth at the Los Helados porphyry Cu-Au deposit (see Figure 3.2).69Chapter 4.  Whole Rock Geochemistry4.1 Hydrothermal alteration effectsWhole-rock geochemical analyses were performed on the different lithologies in Los Helados (appendix B). A total of 27 samples were collected from outcrops and drill-core. Except for Granite and Gabbro-Diorite which were collected from unaltered outcrops, all samples show evidence for some degree of alteration. In these cases, the effect of hydrothermal alteration on whole-rock geochemical compositions has been assessed using a combination of petrography and geochemical parameters.The effects of the K-Na-Ca metasomatism are evaluated graphically in plots by using molar element ratios calculated from whole-rock geochemical data, which is fundamentally the same as the Pearce element ratio technique of Stanley and Madiesky (1994). In these plots, the effects of volume changes are eliminated by comparing ratios with the same denominator, a conserved element, and the expression of geochemical analyses as molar values allow comparison to mineral stoichiometries (Stanley and Madeisky, 1994; Madeisky, 1996). Plots of (2Ca + Na + K)/Al versus K/Al molar ratios provide a graphical means for evaluating the degree of K metasomatism, K, Ca, and Na depletion, and Ca-metasomatism affecting altered rocks. If Al is immobile during hydrothermal alteration, the magnitude of the displacement from a fresh-rock composition is proportional to the actual K, Na, and Ca transferred during hydrothermal alteration (Stanley and Madeisky, 1994). Figure 4.1 shows that samples from Los Helados have a trend toward potassium micas (sericite), which agrees with the intense sericitic alteration documented. The alteration was also assessed using loss-on-ignition (L.O.I) and total sulfur values. The increase of LOI and total sulfur is a proxy for the addition of chlorite, sericite, and sulfide alteration minerals (Fulignati et al.1998). Figure 4.2 shows that except for Granite and Gabbro-Diorite, the rest of the units have values of loss-on-ignition over 3% and total sulfur over 0.3 %. These high values indicate that the analyzed samples suffered a significant hydrothermal alteration and are not suitable for rock classification on the basis of major elements.70Figure 4.1: Plot of (2Ca + Na + K)/Al versus K/Al molar (Stanley and Madeisky, 1994; Madeisky, 1996). Rocks from Los Helados have suffered alkaline metasomatism. The trend of the altered rocks toward K-mica (black arrow) agrees with the widespread sericite alteration documented.Figure 4.2: Loss on ignition (LOI) vs Total sulfurs (TOT/S). The blue lines indicate values on which it is considered intensely altered and not suitable for rock classification on the basis of major elements (Fulignati et al.1998).714.2 Harker Variation DiagramsThe Harker diagrams from the figure 4.3A and 4.3B are applied to examine the geochemical characteristics of the different suits of rocks and also the behavior of a group of elements (Al, Y, K, Na, Fe, Ca, Ti, Sr, Ba, Mg) after the alteration documented at Los Helados.In general, the dataset exhibits three groups based on the silica content. The Gabbro-diorite, the Miocene intrusions and the Permo-Triassic units (Figure 4A and Figure 4B). These three groups can also be discriminated with minor dispersion plotting Al, Y, and Ti (Figure 4A and Figure 4B). Diagrams of Na2O, K2O, Fe2O3, MgO, CaO, Sr and Ba (Figure 4A and Figure 4B) show a greater dispersion showing that these elements were more mobile during the hydrothermal alteration documented in Los Helados. Figure 4.3A: Harker-type diagrams for Los Helados porphyry Cu-Au deposit. The dataset exhibits three groups based on the silica content. These three groups can also be discriminated with minor dispersion plotting Al, Y, and Ti. Diagrams of Na2O, K2O, Fe2O3, MgO, CaO, Sr and Ba show a greater dispersion showing that these elements were more mobile during the hydrothermal alteration documented in Los Helados.72 Figure 4.3B: Harker-type diagrams for Los Helados porphyry Cu-Au deposit. The dataset exhibits three groups based on the silica content. These three groups can also be discriminated with minor dispersion plotting Al, Y, and Ti. Diagrams of Na2O, K2O, Fe2O3, MgO, CaO, Sr and Ba show a greater dispersion showing that these elements were more mobile during the hydrothermal alteration documented in Los Helados.734.3  Trace element classificationThe main limitation of the rock classification based on major elements is the high mobility of SiO2- Na2O- K2O during hydrothermal alteration and such alteration is prevalent at Los Helados. Because of this, the geochemical characterization is done based on high field strength elements (HFSE). High Field Strength Elements such as Zr, Ti, Nb, and Y are generally considered to be much less mobile during hydrothermal alteration and weathering (Pearce, 1996; Winchester and Floyd, 1977).In the Zr/Ti versus Nb/Y classification diagram (Winchester and Floyd, 1977) for volcanic rocks (Figure 4.4), all Miocene porphyries samples are classified in the trachy-andesite field. The more felsic Permo-Triassic rocks are classified as rhyodacites with one sample in the trachy- andesites field while the more mafic rocks fall towards the border andesite/basalt and sub alkali basalt fields. Figure 4.4 Volcanic rock classification: Winchester and Floyd, 1977. Miocene porphyries samples are classified in the trachy-andesite field. The more felsic Permo-Triassic rocks are classified as rhyodacites while the more mafic rocks fall towards the border andesite/basalt and sub alkali basalt fields.744.4 Petrogenetic constraints from REE and trace elementsThe compositional variation of trace elements of Permo-Triassic and Miocene rocks are shown in Figure 4.5. Here, a primitive mantle normalized trace element plot (McDonough et al., 1992) for Los Helados units reveals typical patterns of subduction-related magmas, characterized by enrichment in large ion lithophile (LILE) relative to compatible elements such as heavy REE (HREE), and distinct negative anomalies for Nb, Ta. These elements are not mobilized by arc subduction melting processes (Richards, 2003).The REE all have similar chemical and physical properties. Small differences come from the change in the cation size which decreases systematically with the increasing atomic number from La to Lu. According to the size, REE elements are accommodated to certain mineral lattices. The HREE are preferentially incorporated into garnet and zircon, the medium MREE (Sm to Dy) into hornblende, whereas the light rare earth element (LREE) into titanite, apatite and allanite (Rollinson, 1993).The REE cations are normally 3+, although varying oxidation states can result in Eu and Ce occurring naturally in 2+ and 4+ states respectively. Eu and Ce behave differently depending on the valence estate. The divalent Eu cation substitute for Ca+2 in plagioclase and is thus a sensitive indicator for plagioclase fractionation (negative anomaly). In the case of oxidized magmas, the trivalent Eu does not partition with plagioclase, and no anomaly is observed. The lack of plagioclase fractionation and the suppression of plagioclase fractionation due to high magmatic water content also cause the lack of an Eu anomaly (Richards et al., 2012). On the other hand, a positive anomaly of Eu can indicate either plagioclase accumulation in the rock or fractionation of hornblende (Green and Pearson 1985). Europium anomalies (Table 4.1) are quantified using EuN/ Eu*= EuN/√[(SmN) (GdN)] (Taylor and McLennan,1985).Processes such as partial melting and fractional crystallization influence the REE patterns according to the distribution coefficients and abundances of the minerals involved. Because of this, the bulk rock REE patterns can be used to determine which minerals are present in the residuum where the melts were generated or were fractionated during the magma evolution. Steep REE patterns with heavy rare earth element (HREE) depletion are commonly interpreted as reflecting garnet control—either by fractional crystallization or residual in a melting source (e.g., Kay et al.,1987; Hildreth and Moorbath, 1988; Davidson et al., 2013). The concave-up pattern is interpreted as an amphibole control inherited from the source or primitive magma, reflecting the preference that amphibole has for middle rare earth elements (MREE) over HREE and LREE.75In the multi-element and REE spider diagrams in Figure 4.6 the data are normalized to chondrite (Sun and McDonough, 1989). In this figure, Granite and Feldspar Phyric Rhyodacites share some similar features. Both show negative Eu anomalies and a moderate concave-up pattern of the MREE-HREE inherited from fractionation of plagioclase and also a slight amphibole control in the magma source or primitive magma.The Gabbro-diorite (Figure 4.6, Table 4.1) has the lowest concentration of LREE among Los Helados lithologies. It shows a positive Eu anomaly and a moderate negative slope of MREE- HREE with concentration close to 10 times chondrite.  The Miocene intrusive porphyries display a strong HREE depletion combined with a slightly concave-upward pattern. These rocks do not show an Eu anomaly (Figure 4.6, Table 2).In summary, the rocks analyzed from Los Helados can be grouped into three groups based on  the REE distribution patterns (Granite and Feldspar Phyric Rhyodacites; Gabbro-Diorite; and Miocene porphyries). Except for the Gabbro-Diorite, trace element distribution pattern of the other two groups indicates crustal magma differentiation at progressively higher pressures.The ratio Sm/Yb is a reflection of the MREE to HREE slope and is used to discriminate the residual mineralogy. High values indicate garnet-hornblende, whereas low values indicate pyroxene- plagioclase fractionation (Rollinson, 1993). Table 4.1 shows that Permo-Triassic rocks have values from 1.8 to 2.23 according to a pyroxene-plagioclase fractionation while in the Miocene intrusive porphyries the values range from 4.38 to 7.59 according to a garnet-hornblende fractionation.Abbreviations: GRN: Granite, FPR: Feldspar Phyric Rhyodacites, AND: Andesites, GA/DIO: Gabbro- Diorite, BPP: Biotite Plagioclase Porphyry; BiPP: Bimodal Plagioclase Porphyry; FGPCP; Fine Grained Plagioclase Crowded Porphyry; QFP: Quartz Feldspar Porphyry.Lithology SiO2 %Adakite signatureEu anomalySm/Yb MREE-HREE geometrySr Y Yb Sr/Y La/YbMioceneBPP 62 1049 4.3 0.42 244 55 1 7.59Moderate concave-upwardBiPP 64 563 2.95 0.4 191 38 1 4.38FGPCP 65 524 4.2 0.41 125 31 1 5.17QFP 63 423 5.7 0.35 74 42 1 5.09Permo-Triassic GA/DIO 51 571 15.9 1.6 36 6 1.2 2.23 Moderately decreasing slopeFPR 69 116 13.2 1.5 9 17 0.8 2.1 Moderate concave-upwardGRN 70 244 35.9 2,1 7 10 0.5 1.82 Moderate concave-upwardTable 4.1: Summary of Petrogenetic Indicators 76Figure 4.5: Primitive mantle normalized trace element plot (McDonough et al., 1992). All units reveal typical patterns of subduction-related magmas77  Figure 4.6: Multi-element and REE spider diagram. Data is normalized to chondrite (Sun and McDonough, 1989). Los Helados units can be grouped into three groups based on the REE distribution patterns (Granite and Feldspar Phyric Rhyodacites; Gabbro-Diorite; and Miocene porphyries) 4.5 Adakite-like signature and porphyry fertility indicators of Miocene rocksThe “adakite” terminology was first coined by Defant and Drummond (1990), following the study of Kay (1978), to describe a rare type of magnesian andesite found near Adak Island in the Aleutians. It has been used to describe intermediate (> 56 % silica, mostly dacitic and andesitic) and unusually hydrous rocks, characterized by high La/Yb ratios (high ratios of LREE/HREE), high Sr concentrations (>400 ppm), low Y (<18 ppm). Kay (1978) suggested that these chemical characteristics were consistent with an origin as partial melts of subducted, garnetiferous oceanic crust, which had then reacted and partially equilibrated with the peridotitic asthenospheric mantle wedge during ascent in an oceanic crust.The initial use of the term implied a specific genesis from melting of the subducted slab (Kay, 1978; Defant and Drummond, 1990). However, it has been demonstrated that rocks with adakite- like composition can originate by multiple processes and do not necessarily reflect the initial 78source process (Richards and Kerry, 2007; Castillo, 2012). However, because an adakite is more oxidized and has higher water contents; many porphyry deposits present adakite-like signatures reflected in high Sr/Y and La/Yb ratios. Hence without implying genesis, those ratios still have value to indicate potentially fertile intrusions that may host economic deposits (Thieblemont et al., 1997; Bissig et al., 2017).Miocene rocks from Los Helados all meet the criteria proposed for the definition of adakites. The plot from Figure 4.7A (Defant and Drummond 1990,1993) uses the ratio Sr/Y versus Y to highlight the mutually exclusive roles fractionation of garnet in adakites (yielding high Sr/Y, low Y magmas) versus plagioclase fractionation in normal tholeiitic to calc.alkaline rocks (yielding low Sr/Y and normal to high Y). The plot La/Yb versus silica (Figure 4.7B), also indicates fractionation of garnet and amphibole for the Miocene rocks. These plots clearly distinguish Miocene rocks from Triassic rocks. 79 Figure 4.7: A). Plot of Sr/Y vs. Y (Defant and Drummond, 1993). This plot shows that Miocene rocks from Los Helados all meet the criteria proposed for the definition of adakites B) La/Yb vs. silica (Richards and Kerrich, 2007). This plot indicates fractionation of garnet and amphibole for the Miocene rocks80Chapter 5. Discussion5.1 Miocene magmatic and hydrothermal evolution of Los HeladosBased on geologic mapping, petrography and geochronological data, the Miocene magmatic- hydrothermal history of the Los Helados system can be divided into six stages. These six stages are grouped in pre-mineralization stage 1, inter-mineralization stages 2-3-4-5, of which stages 3 and 4 are the main mineralizing events, and late-mineralization stage 6. Figure 5.1 shows the reconstruction of the Miocene magmatic-hydrothermal history of Los Helados, and Figure 5.2 shows a timetable based on U-Pb geochronological data obtained on zircons, geological mapping, and core logging.CA-ID-TIMS U–Pb zircon geochronology is an effective method to determine the duration of magmatic processes (Rivera et al., 2014; Broderick et al., 2015; Buret et al.,2016). Improvements in the methodology by using chemical abrasion ID-TIMS on single grains has allowed for estimating the age of the eruption or emplacement by assigning the age to the youngest zircon(s) from a zircon population within a single sample (Bachmann et al., 2007; Miller et al., 2007; Schoene et al., 2010a). These methods were used in this study and so allow for the life span of the Miocene Los Helados magmatic system to be estimated between the first and the last stages documented (Figure 5.2); i.e. between 13.97 ± 0.10 Ma (the age obtained for the precursor Quartz Feldspar Porphyry) and 13.75 ± 0.13 (the age obtained for the youngest porphyry, the Biotite Plagioclase Porphyry). This estimation gives a duration of 220 +/- 16 K years for the magmatic processes at Los Helados. Although the median age obtained for the Fine Grained Plagioclase Crowded Porphyry appears to be younger than all other phases, the error on the age determined for this sample was higher and still allows for support of the observed field cross-cutting relationships. The pervasive alteration and intense veining documented in this intrusion could have produced a loss of Pb that resulted in higher variance on individual grains in this sample (Schoene et al.,2013).During the first stage of porphyry related magmatism, the Quartz Feldspar Porphyry was emplaced at Los Helados. Although the Quartz Feldspar Porphyry intrusion appears as a small body in the E-W cross-section, it has a large outcrop extent (400 x 400 m, see the surface map in Figure 2.1) in the southeastern part of the deposit. Results from the outcrop mapping and core logging suggest that the Quartz Feldspar Porphyry is associated with K-feldspar and sericitic alteration.81The highest density of veins within this unit is observed in proximity to the inter-mineralization porphyries and breccias, indicating that this unit was a precursor to the younger mineralization related units. These cross-cutting relationships also agree with the U-Pb age of 13.97 ± 0.10 Ma, which corresponds to the oldest age obtained for the Los Helados porphyries.During the second stage, the Fine Grained Plagioclase Crowded Porphyry was emplaced. This intrusion forms two fingers (Figure 5.1) and was cut by several deep holes. Intense potassic alteration and veining were documented during the drill core logging. Based on the size of these intrusions and the intensity of the alteration, it is possible that this porphyry forms the cupola of a bigger intrusion at depth (Figure 5.1). The CA-ID-TIMS U-Pb zircon analysis gave a 13.5 ± 0.32 Ma for this unit.In the third stage of igneous activity, the Matrix Hydrothermal Breccia intruded the older lithologies as a result of hydrothermal fluid release from the magma. The large cupola of Fine Grained Plagioclase Crowded Porphyry at depth is interpreted to be the source of the rapidly released fluids responsible for explosive breccia formation. The Matrix Rich Breccia is the volumetrically most prominent breccia type of the Los Helados deposit. Generally, the fragment lithologies closely reflect those of the closest wall rocks. The clast composition of this breccia shows an increase of Fine Grained Plagioclase Crowded Porphyry clasts with depth. Close to the breccia contact with the Fine Grained Plagioclase Crowded Porphyry some clasts have a distinctive ragged (or wispy) shape. This clast shape is commonly interpreted to reflect juvenile clasts (e.g., Davies et al., 2008). Juvenile clasts are derived by fragmentation of a parental magma and are a key feature to provide evidence for a direct magmatic contribution to breccia formation and help to infer fragmentation processes (Davies et al., 2008). Thus, the Fine Grained Plagioclase Crowded Porphyry is interpreted here as the causative intrusion of the Matrix Rich Breccia.Stages 2 and 3, comprising the intrusion of Fine Grained Plagioclase Crowded Porphyry and the Matrix Rich Breccia represent the main phase of economic metal (Cu, Au, Ag) deposition into the deposit. Given the size of the of this intrusion and the intensity of the alteration documented within it, the pervasive potassic alteration footprint at Los Helados is associated with the intrusion of the Fine Grained Plagioclase Crowded Porphyry. The decrease in alteration and veining intensity for the later intrusions is consistent with the waning of the magmatic-hydrothermal system (Ulrich and Heinrich, 2002).82Figure 5.1: W-E cross-section at 6864800 N. Reconstruction of the pre-Miocene and Miocene magmatic hydrothermal history of Los Helados.83Stage 4 includes the intrusion of the Cement Rich Breccia. This breccia dips to the west and is located between the Matrix Rich Breccia and the Fine Grained Plagioclase Crowded Porphyry (Figure 5.1). The contact between the Matrix Rich Breccia and the Fine Grained Plagioclase Crowded Porphyry represents a zone of high permeability for the hydrothermal fluids. The Cement Rich Breccia contains a distinctive sequence of hydrothermal minerals that varies according to the vertical elevation. The volume of hydrothermal cement varies between 2 and 25%. In the middle and upper levels (from 400 meters to the top) the cement is composed by pyrite-gypsum- specularite-tourmaline. In the deepest parts, the breccia is cemented by biotite-anhydrite-magnetite- chalcopyrite (Figure 5.3).Similar mineralogical zonation within a hydrothermal breccia body was also documented at Los Bronces in Brecha Sur-Sur by Frikken (2005). There, the mineralogical zonation in the breccia includes a transition from biotite-magnetite-chalcopyrite-anhydrite cement and related biotite alteration upward to tourmaline-specularite-pyrite-gypsum cement and quartz-sericite-tourmaline alteration. A two-stage process in the precipitation of the hydrothermal cement was documented. Figure 5.2: Timetable based on geochronological data obtained on zircons (this thesis) and molybdenite (NGEx Minerals Inc. internal data), Abbreviations: QFP, Quartz Feldspar Porphyry; FGPCP, Fine Grained Plagioclase Crowded Porphyry; BiPP, Bimodal Plagioclase Porphyry; BPP, Biotite Plagioclase Porphyry.84First, the oxide stage, anhydrite, specularite, and tourmaline were deposited from a low salinity, acidic, oxidized hybrid solution. During the second stage (the mineralization stage), quartz, chalcopyrite, magnetite, pyrite, tourmaline, and minor hematite precipitated (Frikken 2005). Based on the range of temperatures of homogenization obtained from fluid inclusions in quartz cement in the Brecha Sur-Sur, Frikken (2005) estimated that the main stage of chalcopyrite deposition in the sulfide cement at Sur-Sur have occurred at temperatures of approximately 450º to 300ºC.If a similar origin is assumed for the Cement Rich Breccia at Los Helados, the temperature conditions required for chalcopyrite precipitation were present between 350 and 1000 meters below the current surface. Below 1000 m depth, the abundance of chalcopyrite decreases.The presence of type 1 veins at depth in Los Helados, also known as early dark micaceous (EDM) veins, is associated with high temperatures. Redmond and Einaudi (2010) documented the presence of “early,” high-temperature veins, similar to the early dark micaceous (EDM) veins of Butte, Montana (Meyer, 1965), that represents the first introduction of copper and gold at temperatures of 500ºC°.During the fifth stage of igneous activity, the Bimodal Plagioclase Porphyry (BiPP) was emplaced. The Bimodal Plagioclase Porphyry is represented by a series of outcrops in the central deposit area that define dikes with a maximum width of 35 m and NNE strike (See map in  figure 2.1) associated with weak sericite alteration.There is a close spatial relationship between the Bimodal Plagioclase Porphyry and the Cement Rich Breccia (Figure 5.1). Certain clasts within the breccia also support a direct relationship to the Bimodal Plagioclase Porphyry. Clasts with irregular shapes from 3 cm to 10 cm of this unit were documented close to the Bimodal Plagioclase Porphyry dikes as a part of the Cement Rich Breccia. They can be classified as juvenile clasts following the definition given by Davies et al., (2008).The last pulse of magmatic activity in Los Helados is represented by the intrusion of the Biotite Plagioclase Porphyry, stage 6. In the cross-section presented in this thesis (Figure 5.1), these intrusions were documented at depths below 600 m from the surface. This late-mineral porphyry has a weak sericite alteration and only late veins (type 8) were documented within this unit.85 Figure 5.3: Comparison between Los Helados Cement Rich Breccia and breccia Sur-Sur from Los Bronces. The figures use the same vertical scale. The central column indicates the variation of the hydrothermal cement according to the depth. The drawings were made on the same scale. The Sur-Sur Breccia drawing is modified from Frikken (2005).865.2  Mineralization stylesMineralization at Los Helados occurs as breccia cement, dissemination, and in veins. Based on the dominant sulfide species, four mineral zones were documented. From top downwards they are pyrite, pyrite-chalcopyrite, chalcopyrite-pyrite and chalcopyrite (Figure 3.20). The ratio of chalcopyrite/pyrite increases downwards. There is a correlation between changes in sulfide species and the alteration zonation through the system.Eleven vein types were consistently logged at Los Helados. Vein densities are used comparatively between intrusive phases. In Los Helados vein densities are not strictly associated with copper grade as the majority of copper was introduced during the breccia phases. The earliest veins documented at Los Helados are the type 1 veins (Table 3.5). These are quartz veins with biotite, potassic feldspar, pyrite and traces of chalcopyrite alteration halo. This type of veins documented at Butte (Meyer, 1965; Brimhall, 1977; Rusk et al., 2008a) and Bingham (Redmond et al., 2004) are formed at temperatures of 500-600 °C.The next veins are the “A” type (Gustafson and Hunt,1975) and are herein described as type 2. These veins are mainly quartz veins with only a minor proportion of chalcopyrite. Type 2 veins are commonly associated with secondary potassic feldspar and secondary biotite alteration halos (Seedorff et al., 2005) formed at lithostatic pressure conditions at high temperatures (≥500°: Monecke et al., 2018). These quartz veins were emplaced in multiple episodes and display a progression from irregular-wavy to straight-walled with time. This pattern is similar to the changes in quartz vein characteristics described at other porphyry deposits (e.g., Gustafson and Hunt, 1975; Sillitoe, 2010; Monecke et al., 2018).The type “B” veins (Gustafson and Hunt, 1975) are the transitional veins and are represented in Los Helados by vein types 3-4-5-6-7 (Table 3.5). These veins were formed at the lithostatic- hydrostatic transition, where large pressure fluctuations are possible (Monecke et al., 2018). These veins have pyrite, chalcopyrite, molybdenite sulfides and gypsum, anhydrite and magnetite gangue.The paragenetically youngest veins documented correspond to “D” type veins (Gustafson and Hunt, 1975) or vein-type 8 at Los Helados. These are pyrite veins with sericite alteration halo and are present throughout all the lithologies.875.3 Molybdenite ageQuartz-molybdenite veins were documented cutting quartz-veins (type 2) and anhydrite- chalcopyrite veins (type 5). Only late pyrite veins (Type 9) cut molybdenite veins. A geochronology analysis by Re-Os on molybdenite gave an age of 13.10 +/- 0.32 My (Re concentration of the sample was between 302.2 ppm and 368.3 ppm). The sample was analyzed at Activation Laboratories  Ltd. Ontario, Canada in September 2011 (NGEx internal report). This age, which post-dates the youngest intrusion within the intrusive sequence (Figure 5.2) is supported by cross-cutting relationships with other vein types determined as part of this project.A similar late age for molybdenum mineralization was also documented at Bingham by Redmond and Einaudi (2010). There, quartz-molybdenite veins postdate the emplacement of the last porphyry and are in turn cut and offset by late quartz-sericite-pyrite veins.5.4  Depth of emplacementEmplacement depth considered here refers to the orebody relative to the surface at the time of mineralization. Murakami et al., (2010) studied 50 Cu-Au±Mo porphyries with the estimated formation depth based on two data types: geological features and microthermometry. Figure 5.4 indicates that the Cu/Au ratio of the ore deposits generally increases with increasing depth and also that Cu-Au deposits form at a shallower emplacement depth than Cu-Mo deposits. The Cu/Au ratio of Los Helados (black vertical line in figure 5.4) is consistent with a depth of emplacement between 1.8 km to 3.3 km when compared to other porphyry deposits. This data agrees with the depth of emplacement estimated from the topographic data in Los Helados where the top of the advanced-argillic alteration is currently exposed at 5250 m.a.s.l., on a high-elevation low relief surface above the deeply incised valley where Los Helados is located. Ore grade mineralization starts at 4200 m.a.s.l. and the mineralization extends to a depth of 3400 m a.s.l. This difference of elevation gives a minimum depth of emplacement of 1850 m.There is no precise measurement of the unroofing that affected Los Helados, which could increase the depth of emplacement considerably. To estimate it, at least the top of the system including most of the advanced argillic lithocap, and it’s contained steam-heated blanket, has been eroded away. There is evidence of the base of the advanced argillic alteration on the highest part of the system to be at 5100 masl. The steam-heated blanket at the El Indio metallogenetic belt (90 km south from Los Helados) can have a thickness of 200 to 300 m (Holley et al. 2017). This gives a minimum or 88unroofing of 300 m for Los Helados. The El Indio metalogenetic belt hydrothermal activity took place over a 3 m.y. (between 13.12 ± 0.18 Ma and 10.09 ± 0.08 Ma) period in the middle to late Miocene, based on 40Ar/39Ar analyses of alunite and jarosite (Holley et al.,2016). These ages coincide with the emplacement of Los Helados Porphyry. Using this estimate, the minimum depth of emplacement at Los Helados would be approximately 2150 m deep.On the other hand, Sillitoe et al., (2019) estimated an unroofing of more than 1000 m for Josemaria Cu-Au porphyry. In this case, the deposit formed at 24 to 24.5 Ma which is considerably older than Los Helados.Au-rich deposits from the Maricunga belt show a shallower emplacement depth than the Los Helados Cu-Au porphyry. Muntean and Einaudi (2001) estimated depth of emplacement of 0.5 to 1.5 km for Au-rich porphyries of the Maricunga belt (Figure 5.4). Sillitoe (1997) noted that the comagmatic extrusive and subvolcanic activity in the gold-mineralization centers of the Maricunga belt indicates a shallow depth of ore deposition.Figure 5.4: Modified from Murakami et al., (2010). Relationships between Cu/Au ratio and depth. The estimated depth of porphyry-style deposits decreases with decreasing Cu/Au ratio. Solid lines are showing fitted trends for geological depth estimates (blue) and fluid inclusion microthermometry (red). The dashed vertical line indicates a molar Cu/ Au ratio of 4.0×104 as defined in Kesler et al. (2002) to separate copper-gold deposits from copper ± molybdenum deposits. The solid black vertical line indicates the Cu/Au molar ratio of Los Helados.895.5 Variation of white mica composition and its relationship with copper mineralization.The spectral investigation of the Los Helados alteration system has focused on white micas because of their well understood spectral response and ubiquitous presence in a range of alteration zones. The wavelengths of Al(OH) absorption features in Los Helados spectra range between 2190 and 2220 nm (Table 5.1) suggesting that the Los Helados rocks contain white micas of diverse compositions, from paragonitic muscovite to and phengitic muscovite. The values and location of each sample can be revised in appendix D.Table 5.1: The characteristics of the Al-OH absorption feature for white micas (Modified from Thompson et al., 1999)Mineral FormulaCharacteristic SWIR absorption featureWavelength of Al-OH absorption (2200 approx.)Muscovite (KAl2(AlSi3)O10(OH)2)Sharp feature at 1400, 1910, 2200nm.2198-2208 nmParagonite NaAl2Al3O10(OH)2 Similar to muscovite 2185-2193 nmPhengitic muscovite3K(Fe Mg) 0.5Al1.5 Similar to muscovite 2208-2215 nm(Al0.5Si3.5)O10(OH)2On the E-W cross-section developed as part of this project, four zones are distinguished based on the range of the AlOH absorption feature wavelength and copper grades (Figure 5.5). The zones are roughly coincident with the alteration zones described in chapter 3 determined by mineral assemblages. The upper central zone composed by Feldspar Phyric Rhyodacites and Granite (yellow dashed line) coincides with the sericitic zone and has the lowest wavelength of the AL(OH) absorption feature (2190 to 2204 nm). The white micas here have a muscovite and paragonitic muscovite composition. These aluminum-rich micas indicate an acidic environment of formation (Cohen, 2011; Halley, 2012). There are two groups of samples within this zone (Figure 5.6): In the first group the wavelengths are lower than 2202 nm and copper values below 2000 ppm (yellow squares); in the second group samples have wavelengths between 2202-2204 nm and copper values between 3500-5500 ppm (yellow triangles). This latter group represents a superposition of sericite alteration over earlier sericite-magnetite-chlorite alteration. The superposition of sericite alteration over the earlier alteration assemblages is also supported by the presence of “A” type veins in the sericite alteration zone which indicates the original presence of potassic alteration.90At the periphery of this central area, the weak sericitic zone (light blue dashed line in figure 5.5) was documented on Granites and Feldspar Phyric Rhyodacites. The absorption wavelengths are between 2204 and 2210 nm, indicating a muscovite composition. The copper grade in this zone has values lower than 2500 ppm and decreases rapidly with distance from the center of the system towards the margins.The central zone (green dashed line in figure 5.5) is lithologically controlled by the presence of the Matrix Rich Breccia. It includes the sericite-magnetite-chlorite alteration and the top of potassic alteration and has the highest wavelength of the Al(OH) absorption feature in this zone ranges from 2205nm up to 2220 nm, but mostly between 2205 nm and 2212 nm. The white micas have a greenish color and correspond to a phengitic and muscovitic composition suggesting a more neutral environment than the sericitic alteration zone (Cohen, 2011; Halley, 2012).Figure 5.5: E-W cross-section showing alteration domains and the variation of the 2200nm absorption feature with depth.91Figure 5.6: Relationship of the wavelengths of the 2200 absorption feature, copper grade, and depth for drillhole LHDH24 (see appendix D for SWIR data). Dashed lines in the uppermost window represent the zones described for the E-W cross-section. Yellow triangles represent superposition of sericite alteration (telescoping) over earlier sericite-magnetite-chlorite alteration.92The lower zone (Magenta dashed line in figure 5.5) includes the Matrix Rich Breccia and the Gabbro-Diorite. It is within the potassic zone and has intermediate values in the range of 2202 to 2210 nm, although the majority of the data is between 2207 and 2210 nm. These values suggest normal muscovite composition. Here, the muscovite was documented in alteration halos in pyrite veins (type 8 or “D” veins from Gustafson and Hunt, 1975).The economic ore metal (Cu, Au, Ag) at Los Helados is found below the zone with the longest wavelengths of the Al (OH) absorption feature, associated with phengite composition, indicating the copper deposition in less acidic conditions (Figure 5.5 and 5.6).5.5.1 White mica crystallinityThe degree of crystallinity of phyllosilicate minerals can be used to infer relative changes in temperature (Merriman and Frey, 1999) with a greater degree of crystallinity indicating higher formation temperatures.Thirteen samples were chosen for calculating the white mica crystallinity at different depths and within different alteration zones. The white-mica crystallinity was calculated using the x-ray powder diffraction method. X-ray diffraction was used to determine the Kübler Index to calculate the crystallinity of the white micas. It is determined from the width of the basal 10Å illite peak at half the maximum peak height. The more crystalline minerals yield lower values. The Kübler Index is negatively correlated with crystallinity (Merriman and Frey, 1999).Table 5.2 indicates that the crystallinity values of the white micas calculated by the Kübler Index give lower values for samples in the potassic zone, which agrees with higher temperatures of formation.The samples analyzed were from two holes that both record a transition from upper sericitic alteration, through sericite-magnetite-chlorite, to deeper potassic alteration. A similar transition from lower values of crystallinity in the sericitic alteration zone, through to progressively higher values in the potassic alteration zone occurred in both holes.935.6 Temperature and pH gradientThe evolution of the hydrothermal-magmatic fluids within porphyry and epithermal systems has been extensively studied (Pudack et al., 2009; Reed et al., 2013; Hedenquist and Taran (2013) among others). Reed et al. (2013), modeled the reactions of a magmatic fluid at Butte, Montana. These authors concluded that the occurrence of the classical assemblage of porphyry copper deposit alteration types (potassic, sericitic, propylitic, and advanced argillic) is a consequence of their origin from a single fluid composition. As the magmatic-hydrothermal system cools, fluids change from neutral to acidic pH. One important factor for the neutral-to-acidic pH change with decreasing temperature is that SO2(aq), is the dominant sulfur species at high temperature, but it disproportionates with decreasing temperature, forming sulfuric acid and H2S. This chemical reaction highlights the importance of sulfur species in controlling pH supplying H+ to the hydrothermal fluid.The depth of emplacement of Butte was estimated by Murakami et al., (2010) between 7 and 7.5 km. Although Los Helados has a shallower depth of emplacement, the similarities with Butte in the composition of the host rock and the variation of the with micas indicate that the process of hydrothermal alteration that acted was similar in both deposits.Pudack et al., (2019) studied fluid inclusions on different quartz generations at Nevados de Famatina Hole ID depth Alt KILHDH20150Sericite0.148290 0.151330 Sericite magnetite chlorite0.152580 0.147640Potassic0.131720 0.133LHDH2460Sericite0.148130 0.16290 Sericite magnetite chlorite0.157380 0.159460 0.157630Potassic0.132700 0.127 Table 5.2: White micas crystallinity values determined by the Kubler Index (KI) for drill holes LHDH 20 and LHDH24. The Kübler Index is negatively correlated with crystallinity. The more crystalline minerals yield lower values. 94(northwest Argentina) to reconstruct the evolution of hydrothermal fluids from a deep magmatic source to the shallow epithermal environment. The depth of emplacement was estimated to be 1.7 km. The authors also concluded that paragenesis of quartz and sulfides at Famatina can be explained by one common source fluid.5.7 Metallogenetic context of Los HeladosGiven that Los Helados is located between two well-known Miocene metallogenetic belts (Maricunga to the north and El Indio belt to the south), it’s assignment to either of these belts, or an entirely separate metallogenic domain within the Miocene arc has been questioned (Sillitoe et al.,2019). Regional comparisons are made based on the data presented in chapter one (description of Maricunga and El Indio belts) and the data presented in chapters two and three.Two deposits of each sector were chosen for comparison. For the Maricunga belt Cerro Casale and Caspiche (both porphyry Au-Cu), for El Indio belt Veladero and Pascua-Lama (both high sulfidation epithermal Au-Ag) and for the study area Caserones (Porphyry Cu-Mo) and Los Helados (Cu-Au). Figure 5.7 shows the location of these deposits and the metallogenetic belts that are discussed here. The characteristics of each deposit are summarized in table 5.3.5.7.1 El Indio metallogenetic belt and Los HeladosAs can be seen from the figure 5.7 and table 5.3, besides the 100 km that separate them, there are differences in style of mineralization, age, tectonic environment and host rock between deposits from the El Indio Belt and the Los Helados area,The deposits and prospects of El Indio belt are defined by a series of advanced argillic alteration zones and contain high-sulfidation epithermal gold-silver ± copper mineralization (Maksaev et al., 1984; Martin et al., 1995; Bissig et al., 2001; Bissig et al., 2015). The age of these deposits ranges from 13 to 8 Ma and they are located close to the center of the Pampean flat-slab segment.5.7.2 Maricunga metallogenetic belt and Los HeladosDeposits of the Maricunga belt and Los Helados area share some characteristics. The ages of the deposits in the Maricunga belt range from 25 to 12.6 Ma and Los Helados is at the younger end of this age-range. They are situated geographically close (Cerro Casale is 60 km N of Los Helados). 95 Figure 5.7: Location of Los Helados respect to the Maricunga and El Indio belt. It also shown latest Oligocene- Miocene porphyry and high-sulfidation (HS) epithermal deposits in the El Indio and Maricunga metallogenetic belts, northern Chile. Modified from Cahill and Isacks (1992). The main differences between the Maricunga belt and Los Helados include different host rocks, mineralization styles, and depth of emplacement.96 Table 5.3: Characteristics of the selected deposits from Maricunga belt, El Indio belt and Los Helados area.Belt DepositDeposit typeAu Million OzCu Billion LbAg Million OzAge (Ma) Elevation SourceMaricunga Cero Casale Porphyry 11.62 2.89 29.34 15.8-13.9 4200- 4500 Munizaga,  2016CaspichePorphyry Au-Cu11.62 2.49 27.12 25 4100-4400 Sillitoe  et al., 2013Los Helados areaLos HeladosPorphyry  Cu-Au 5.7 9.7 49.2 13.9 13.5 4100-4600NGEX press release 2014;   This thesisCaserones Porphyry Cu-Mo7.08 17.5 4600Ramirez, 2010;            Caserones.clEl IndioVeladeroHigh sulfidation12.612.70±0.02 and 8.58±0.174200-4400Charchaflie et al.,  2007;  Holley  et al., 2012;    Holley 2012        Pascua-LamaHigh sulfidation26 8.8±0.6 4300-4500Deyell 2005;                           Bissig, 2002 ;         Chouinard et al., 2005The porphyry deposits from Maricunga, including those at Marte, Lobo, Refugio, La Pepa, and Volcán, typically contain gold as the only economically extractable metal, whereas those at Caspiche and Cerro Casale contain gold plus by-product copper potential. On the other hand, the deposits of the Los Helados area have copper as the main economically extractable mineral and gold or molybdenum (Los Caserones porphyry) as a by-product (Table 5.3).The main characteristic of the Maricunga belt is the N-NE trending chain of andesitic to dacitic composite volcanoes, part of a Miocene continental margin volcanoplutonic arc Muntean and Einaudi, 2001). These composite volcanoes are the main hosts for the deposits (La Pepa, Cerro Casale, Caspiche). Gamonal (2015) made a compilation of time and space distribution of volcanic rocks. This compilation is shown in figure 5.8. There, it can be seen that the four periods (26-21 Ma; 21-17 Ma; 17-11 Ma; 11-4 Ma) are well represented in the Maricunga belt but to the south of 28° (south of Cerro Casale and Caspiche) the extent of Neogene volcanic rocks decreases and the Tertiary volcanic activity is only represented by rocks of the period 21-17 Ma. This absence of rocks belonging to the two most important mineralizing periods of Maricunga (26-21 Ma and 17-11 Ma) has discouraged the exploration in this area in the past. Figure 5.9 (based in Maksaev 2014 and Carrizo and Herrera 2019) illustrates the increase of Triassic graintoids to the south of the 28°.97In summary, the 28 °S latitude represents the limit where volcanic rocks dominate to the north and Triassic granitoids to the south, marking a difference between the Maricunga belt, and the region that includes Los Helados.The vein types in the Marincunga belt were summarized by Muntean and Einaudi (2001) (Table 5.4). These authors grouped Maricunga belt veins into 4 classes (Table 5.4): A-veinlets (Gustafson and Hunt, 1975), banded quartz veinlets (Vila and Sillitoe, 1991; Vila et al., 1991; King, 1992; Muntean and Einaudi, 2000), D-veins (cf. Gustafson and Hunt, 1975), and quartz-alunite ledges (cf. Ransome, 1909).The earliest vein-type seen in Maricunga are A-veins consisting of quartz-magnetite-biotite- chalcopyrite with variable contents of potassic feldspar, pyrite, and other minerals (Muntean and Einaudi 2001).The banded quartz veinlets are the dominant veinlets in most Au-only porphyry deposits, as documented in the Maricunga belt (Muntean and Einaudi, 2000, 2001) and other shallow gold-rich porphyry deposits (Kodera et al., 2014; Rottier et al., 2016). These veins comprise layers of both translucent and dark-gray quartz (Vila and Sillitoe, 1991; Muntean and Einaudi, 2000, 2001), the color of the latter commonly caused by abundant vapor-rich fluid inclusions (Muntean and Einaudi, 2000).The high abundance of vapor-rich inclusions suggests that the quartz in these veins formed as a result of rapid decompression in shallow environments (<1,5 km: Monecke et al.,2018). This may have been caused by flashing of high-temperature magmatic-hydrothermal fluids (Muntean and Einaudi, 2000, 2001). Multielement analyses by Muntean and Einaudi (2001) indicate that these veins make a significant Au contribution. Zones where banded quartz veinlets predominate typically contain 0.5 to 2 ppm Au and less than 0.1 % Cu.D-veins documented in the Maricunga porphyries are similar to the ones described by Gustafson and Hunt (1975). These veins are formed by open-space filling composed of pyrite- quartz with a quartz-sericite-pyrite alteration halo.Quartz-alunite ledges are steeply-dipping replacement veins typical of the high-sulfidation epithermal environment (Muntean and Einaudi, 2001). The width of these quartz-alunite ledges varies from centimeters to meters. Some deposits as La Pepa have quartz-alunite ledges with high values of gold while others like Co. Casale do not have mineable gold (Vila and Sillitoe 1991).98Figure 5.8: Volcanic and hypabyssal rocks and porphyry/epithermal deposits of the Maricunga and El Indio metallogenic belts (Compiled by Gamonal 2015). The four periods are well represented in the Maricunga belt but to the south of 28, volcanic activity is only represented by rocks of the period 21-17 Ma.99 Abbreviations: Bio: Biotite; Cpy: chalcopyrite; Chl; chlorite; Epi: epidote; Gyp: gypsum; Kfs: potassic feldspar; Qz: quartz; Mg: magnetite;; Py: pyrite; Rt: rutile; Ser: sericiteThe most important difference of Maricunga deposits with respect to Los Helados and Caserones is the presence of banded quartz veins. These veins have high values of Au and low Cu which explain the high grade of Au in Maricunga porphyries and the particular Au/Cu signatures of the more Cu-rich deposits such as Los Helados area. The presence of these veins is also in accordance with a shallower environment of formation for the Maricunga deposits (<1.5 km) in comparison to the slightly deeper Los Helados (1.8-2.15 km)Vein Type SourceMain mineral associtaionSubordinate mineralsWidth  Alteration Halo Width AGustafson and Hunt (1975)Bio-Qz-Mg-Cpy-KfsPy-Chl-Bio 1-20 mm Ksp 1-10 mmBanded quartz veinletsVila and Sillitoe, 1991Qz-Kfs-Chl-Py-MgtEpi-Gyp-Cpy-Sp-Bn1-20 mm DGustafson and Hunt (1975)Qz-Py Ser-Sp-Cpy 1 mm Qz-Ser-Py mm to cmQuartz-alunite ledgesMuntean and Einaudi, 2001 Qz-Alu-Py Rt 0.5-5 m Qz-Kao-Py-Ser m Another difference of the Maricunga belts is that numerous districts (Co. Casale, La Pepa) are characterized by zones of advanced argillic assemblages such as the La Pepa host high-sulfidation epithermal gold close to the porphyry Au deposits (Muntean and Einaudi 2001). Los Helados and Caserones do only have subordinate advanced argillic alteration zones and no significant associated Au mineralization.5.8  Regional-scale faults and segmentation of Los AndesLos Helados is located in a complex tectonic environment. It is situated along the southwestern edge of the Altiplano-Puna plateau, close to the southern boundary of the active Central Volcanic Zone of the Andes that has a flat subduction amagmatic zone between 28° and 33°S (Thorpe et al., 1982; Cahill and Isacks, 1992; Kay and Mpodozis, 2002; Figure 5.7). This area is considered to be a major tectonic discontinuity of the Andean margin (Moore, 1979; Walker et al., 1991). However, large-scale NNW and NNE lineaments that can be traced from the Chilean Pacific coast to across the Cordillera Occidental and into the Puna (Figure 5.9), are considered to play an important role in Andes segmentation at this latitude. These lineaments, named as “translithospheric faults” Table 5.4: Summary of the characteristics of the veins present in the Maricunga metallogenic belt.100by Jacques (2003), O’Reilly et al. (2005), Griffin et al. (2013), and Carrizo and Herrera (2019). The origin of the “translitospheric fault” is explained by the complex history of supercontinents, assembly, breakup and collisions in the western margin of South America (i.e. Rapela et al., 1998a, b; Lucassen et al., 2000; Ramos, 2008a, b; Ramos, 2009; Hervé et al., 2007; Rapalini et al., 2010). Carrizo and Herrera (2019) consider that these transverse structures control the distribution of the geologic units. The Los Helados deposit is separated from the Maricunga deposits by two of these “translitospheric faults”, El Potro and Chañaral (Figure5.9). The map in figure 5.9 highlights the control on the emplacement  of the Triassic granitoids.The tectonomagmatic relevance of the “translithospheric faults” has been the focus of numerous studies (Clark et al., 1976 and Sillitoe (1981, 1988); Richards et al., 2001; Richards (2003); Carrizo and Herrera (2019)) and it could explain the differences in terms of host rock and depth of emplacement, uplift rate and erosion histories between deposits from the Maricunga metallogenetic belt and Los Helados deposit.101Figure 5.9: Map showing the distribution of the Late Paleozoic to Late Triassic rocks of northern Chile between latitudes 26° and 31°S (Modified from Maksaev 2014) showing the locations of “translithospheric” regional-scale faults (modified from Carrizo and Herrera (2019) and referenced therein)102Chapter 6. Conclusion, exploration implications and future work6.1 ConclusionsThis section summarizes the main conclusions based on new geological, geochronological, and geochemical data presented in this thesis.6.1.1 Miocene magmatic and hydrothermal evolution.New geological and geochronological evidence indicates that multiple intrusion and brecciation events occurred during the late Miocene in the Los Helados porphyry Cu-Au deposit. A minimum of four porphyry and two breccia units were distinguished. These six stages are grouped in pre-mineralization (stage 1), inter-mineralization (stages 2-3-4-5), and late- mineralization (stage 6).The pre-mineralization stage 1 (Quartz Feldspar Porphyry) is considered the precursor to the mineralization. This intrusive unit is associated with local k-feldspar and sericitic alteration. The inter-mineralization stages comprise Fine Grained Plagioclase Crowded Porphyry (stage 2), Matrix Rich Breccia (stage 3), Cement Rich Breccia (stage 4) and Bimodal Plagioclase Porphyry (stage 5). Two mineralization events were recorded at Los Helados: The first and most important alteration and mineralization event is related to stages 2 and 3, comprising the intrusion of Fine Grained Plagioclase Crowded Porphyry and the Matrix Rich Breccia respectively. The Fine Grained Plagioclase Crowded Porphyry is the most significant intrusion body which forms a big magmatic cupola at depth that accumulated fluids and gases to produce high-energy brecciation and intense veining and hydrothermal alteration. The brecciation produced the Matrix Rich Breccia, which is the volumetrically most prominent breccia type of the Los Helados deposit and hosts most of the copper mineralization. The second event of mineralization (stage 4), is related to the intrusion of the Cement Rich Breccia. This low energy breccia intrudes the Matrix Rich Breccia and the Feldspar Phyric Rhyodacite. It has an average width of 75 m and hosts the highest copper grades at Los Helados. The inter-mineralization stages finish with the intrusion of the Bimodal Plagioclase Porphyry (stage 5) represented by a series of outcrops that define dikes with a maximum width of 35 m related to a weak sericitic alteration and copper grade below 0.1 %. Late-mineralization (stage 6) is represented by Biotite Plagioclase Porphyry and is related to weak sericitic alteration. These intrusions represent the last magmatic phase in Los Helados.103New CA-ID-TIMS U–Pb zircon geochronology performed on the Miocene porphyries allowed to determine the duration of magmatic processes. Los Helados magmatic system to be estimated between the first and the last stages documented (Figure 5.2); i.e. between 13.97 ± 0.10 Ma (the age obtained for the precursor Quartz Feldspar Porphyry) and 13.75 ± 0.13 (the age obtained for the youngest porphyry, the Biotite Plagioclase Porphyry). This estimation gives a duration of 0.22 +/- 0.16 Ma for the magmatic processes at Los Helados.6.1.2 Sulfide mineralization and copper distributionFour mineral zones were documented at Los Helados, from the top downwards they are: pyrite, pyrite>chalcopyrite, chalcopyrite>pyrite and chalcopyrite. There is a correlation between changes in dominant sulfide species and the alteration zonation through the system.Copper grade distribution shows a strong lithological control at Los Helados. The Matrix Rich Breccia, the volumetrically most prominent breccia type, represents the main phase of economic metal deposition into the deposit. The temperature and pressure conditions required for chalcopyrite precipitation during the first event of mineralization were present at Los Helados between 350 and 1000 meters below the current surface. Below 1000 m depth, the presence of chalcopyrite decreases.The second breccia event (Cement Rich Breccia), richer in breccia-cement shows the highest copper values but it has smaller dimensions than the Matrix Rich Breccia. Based on cross-section on figures 2.2 and 2.3, this breccia extends to grater depth than 1000 m but decreases in diameter. It has the largest dimension on surface with approximately 400 m in the north-south section and 100 m in the east-west section. At a depth of 1000 meters below the surface, this breccia has a dimension of 100 x 100 m. The depth of this breccia has not been tested by drilling.6.1.3 White micas and pH and copper sulfide mineralsIn a vertical profile, three zones are distinguished based on the range of the AlOH absorption feature wavelength and copper grades. The upper part of the system coincides with the sericitic zone and has the lowest 2200 absorption feature wavelength (2190-2204 nm). The white micas here have a muscovite and paragonitic muscovite composition indicating an acidic environment of formation. This zone is dominated by pyrite with low copper grades. The central zone includes the sericite-magnetite-chlorite alteration and the top of potassic alteration and has the highest wavelength of the Al(OH) absorption feature in this zone ranges from 2205nm up to 2220 nm indicating less 104acidic conditions. The white micas here have a muscovite and phengitic-muscovite composition. The lower zone is within the potassic zone and has intermediate values in the range of 2202 to 2210 nm. The white mica crystallinity from the potassic zone is higher than in the sericitic and sericite- magnetite-chlorite zones. This agrees with higher temperatures for the potassic alteration assemblages.The economic ore metal (Cu, Au, Ag) at Los Helados is found in the zone with the longest wavelengths of the Al (OH) absorption feature, associated with phengite composition, indicating the copper deposition in less acidic conditions. 6.1.4 Metallogenetic context of Los HeladosThe orogen-parallel structures and NNW translithospheric faults have produced the segmentation of the Andes cordillera at The Los Helados latitude. Here the segmentation is evidenced by changes in the host rock, mineralization style and depth of emplacement. Au-rich porphyries and epithermal deposits from the Maricunga metallogenetic belt are emplaced in Miocene volcanic rocks at shallow emplacement levels. Toward the south, Cu (+/-Au) rich porphyries and epithermal deposits are emplaced in Permian to -Triassic granitoids at deeper emplacement levels.Given the differences in mineralization styles, host-rock and depth of emplacement, the Los Helados area deposits are metallogenetically different from the Maricunga belt deposits.6.2 Exploration implications: On a regional scale, the “translithospheric faults” have important tectonomagmatic relevance in the thesis area (Clark et al., 1976; Sillitoe (1981, 1988); Richards et al., 2001; Richards (2003); Carrizo and Herrera (2019)), and they can explain the differences in terms of host rock, depth of emplacement, mineralization style between deposits from the Maricunga metallogenetic belt and Los Helados deposit. In the past decades, the exploration of deposits in the study area was carried out using the model for the classic Maricunga deposits. After analyzing the differences between these deposits the parameters for the exploration should be modified for achieving greater success.Los Helados is hosted in late Paleozoic to Triassic granites whereas the deposits of the Maricunga belt are hosted in Miocene volcanic rocks. These differences lead to contrasting geometry, size of surface and vertical alteration footprint. Surface alteration footprint from Maricunga deposits can reach 10 km in diameter (Cerro Casale, Caspiche, La Copipa) (Davidson and Mpodozis (1991), 105satellite images). At Los Helados, the visible hydrothermal alteration footprint decreases laterally over a short distance. As a result, the surface alteration footprint covers a smaller area (2 km in diameter). Extensive outcrops and covered areas dominated by Pemo-Triassic granitoids are present to the south of the 28 °S latitude. This area has big exploration potential for hosting hydrothermal system with smaller alteration footprint than the Maricunga deposits.For Los Helados Cu-Au porphyry, a poorly mineralized lithocaps associated with the hydrothermal system and a deeper emplacement level of the orebody relative to the surface at the time of mineralization is evident, compared with the adjacent Maricunga belt Au-rich porphyries. Considering these two characteristics, the exploration should be open to testing deeper targets up to 1500 m below lithocaps where preserved. On a local scale, the ore-mineralization is lithologically controlled at Los Helados. Two breccia phases control the distribution of Cu. The first one, related to the Matrix Rich Breccia is the volumetrically most prominent breccia type of the Los Helados and represents the main phase of economic metal (Cu, Au, Ag) deposition into the deposit. The second event is represented by the Cement Rich Breccia, lithology cross-sections (figures 2.2 and 2.3) indicate that this breccia has a NS elongate axis. Surface dimension can reach 400 m in the NS direction and 150 m EW direction and get narrower toward the bottom. At 1000 m below surface the Cement Rich Breccia has a dimension of 100 x 100 m.SWIR spectral analysis has demonstrated to be a powerful tool to detect changes in temperature and acidity conditions (Cohen, 2011; Halley, 2012). Applying this technique regionally and locally could benefit the exploration results. At deposit scale, the location of the ALOH feature and white mica crystallinity could be used as a vector to Cu mineralization. SWIR spectral analysis in Los Helados hydrothermal sericite has AlOH spectral values between 2190 and 2220 nm. However, sericite associated with high Cu grades features wavelength values 2202 and 2210 nm. At a regional scale, the application of this technique in covered areas could help in the identification of new targets. Small variations in wavelength may vector towards a potential new target.6.3 Future work To help further understanding the Miocene magmatic and hydrothermal history of Los Helados and district scale exploration additional work is recommended. 106• To better constrain the duration of the magmatic and hydrothermal activity at Los Helados, it is recommended to increase the number of U-Pb samples on Miocene porphyries and also perform 40Ar/39Ar analyses of alunite and muscovite to determine the duration of the hydrothermal activity and link the lithocap formation into the intrusive history. • Fluid inclusion can assist to establish the depth of emplacement and to determine the thermodynamic evolution of the fluids responsible for the mineralization. • With the current level of knowledge of the anatomy, lithology, alteration, and mineralization of Los Helados porphyry, it is recommended to extend the analysis to the rest of the drill holes an update of the model. 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A., 1977, Geochemical discrimination of different magma series and their differentiation products using immobile elements: Chemical Geology, 20, 325-343.Winocur, D.A., Litvak, V.D., Ramos, V.A., 2014, Magmatic and tectonic evolution of the Oligocene Valle del Cura basin, Main Andes of Argentina and Chile: evidence for generalized extension: Geological Society of London Special Publication N° 399.Zentilli, M., 1974, Geological evolution and metallogenetic relationships in the Andes of northern Chile between 26° and 29° south: Unpublished Ph.D. thesis, Queen´s University, Ontario, Canada. 118Appendix A:   PetrographyTable A1:  Location for petrography  samples.Sample ID Thin sec-tionPolished section Analyte HOLE-ID DEPTHUTM W84E 19SUTM W84N 19S ALT DEMAG0001 X Drill Core LHDH17 157AG0002 X Drill Core LHDH17 439AG0003 X Drill Core LHDH17 358AG0004 X Drill Core LHDH17 589AG0005 X Drill Core LHDH17 705AG0006 X Drill Core LHDH17 755AG0007 X Drill Core LHDH17 1009AG0008 X Drill Core LHDH17 1182AG0009 X Drill Core LHDH21 25AG0010 X Drill Core LHDH21 260AG0011 X Drill Core LHDH21 342AG0012 X Drill Core LHDH21 554AG0013 X Drill Core LHDH21 725AG0014 X Drill Core LHDH21 1016AG0015 X Drill Core LHDH21 1141AG0016 X Drill Core LHDH21 1230AG0018 X Drill Core LHDH21 1399AG0019 X Drill Core LHDH28 679AG0020 X Drill Core LHDH28 779AG0021 X Drill Core LHDH28 947AG0022 X Outcrop 442795 6864581 4674AG0023 X Outcrop 441325 6864771 4839AG0024 X Outcrop 442340 6864630 4744AG0025 X Outcrop 442822 6864603 4698AG0026 X Outcrop 443208 6865700 3564AG0027 X Outcrop 442853 6863784 5144AG0028 X Drill Core LHDH28 496AG0029 X Drill Core LHDH29 521AG200 X Drill Core LHDH34 920AG201 X Drill Core LHDH50 93AG202 X Drill Core LHDH50 679AG203 X Drill Core LHDH26 958AG204 X Drill Core LHDH30 741AG205 X Drill Core LHDH72 401AG206 X Drill Core LHDH21 320AG207 X Drill Core LHDH22 720AG208 X Drill Core LHDH50 860AG210 X Drill Core LHDH24 380AG211 X Drill Core LHDH13 358AG217 X Drill Core LHDH21 1330120Figure A2: Thin section-XLP. Sample  AG0001Figure A1: Hand sample. Sample  AG0001.      Figure A3: Microphotograph: Magnification 2X   XLP. Sample  AG0001Description: Rock with porphyritic textur, light grey colour. It is formed by anhedral  phenocrists of plagioclase up to 3 mm totally altered to sericite. Abundant quartz phenocrysts up to 3.3 mm (the average is 1.5) with partial  magmatic reasorption. The groundmass is afanitic and it is formed by anhedral crystal of quartz-sericite <0,1mm. The rock is cut by quartz veins (type 2C).Phenocrysts 30 %Mineral % AlterationPlagioclase 25 SericiteQuartz 5Groundmass 70 % AlterationFeldspar 28 SericiteQuartz 35Opaques 2Sample ID DDH Depth m Rock Type AlterationAG0001    LHDH17 157 FPR Sericite-quartzTable A2: Description of the sample  AG0001121Figure A6: Microphotograph. Magnification 2X -XLP.Sample   AG003.Figure A5: Thin section-XLP. Sample   AG003.Figure A4: Hand sample. Sample   AG003. Description and notes: Rock with porphyritic texture, light grey colour. It is formed by anhedral phenocrists of plagioclase up to 3 mm totally altered to sericite. The groundmass is aphanitic formed by feldspar and quartz. Two set of quartz veins  (2D) are present in this sample .Phenocrysts 30 %Mineral % AlterationPLagioclase 23 SericiteQuartz 7Groundmass 70% AlterationFeldspar 25 SericiteQuartz 38Opaques 7Sample ID DDH Depth m Rock Type AlterationAG0003 LHDH17 358 FPR Sericite quartzTable A3: Description of the sample  AG0003122Figure A8: Thin section-XLP. Sample AG0002. Figure A7: Hand sample Photograph. Sample AG0002.  Description and notes:  Rock with porphyritic texture, whitish  in colour, composed  by plagioclase phenocriyst up to 3mm (subhedrals). Plagioclases are  partially raplaced by sericite (twinnings are partially visibles) ; Phenocrystals  of biotite up to 2.5 mm  are altered to chlorite  .  Tje groundmas is aphanitic composed by  plagioclase and quartz.Phenocrysts 40 % Mineral % AlterationPLagioclase 30 Weak sericiteBiotite 10Groundmass 60 % AlterationPlagioclase 20 SericiteQuartz 40 ChloriteSample ID DDH Depth m Rock Type AlterationAG0002 LHDH17 439 BPP SericiteTable A4: Description of the sample  AG0002123Figure A11: Microphotograph. Magnification 2X -XLP. Sample AG0004.Figure A10: Thin section-XLP. Sample AG0004.Figure A9: Hand sample Photograph. Sample AG0004. %Mineral % AlterationGroundmass % AlterationDescription and notes: aphanitic texture. Intense alteration. The original textur can not be seen. The phenocrystals have been completely remplaced by sericite. Quartz veins  (2 D)cut the sample.Sample ID DDH Depth m Rock Type AlterationAG0004 LHDH17 589 undetermined SericiteTable A5: Description of the sample  AG0004124Figure A13: Thin section-XLP. Sample AG0005.Figure A12: Hand sample Photograph . Sample AG0005. Description and notes: Quartz phenocrysts up to 3.5 mm, clear and subrounded. Plagioclase phenocrysts are totally replaced by sericite. Phenocrysts 30 %Mineral % AlterationQuartz 20Plagioclase 10 SericiteGroundmass 70 % AlterationQuartzplagioclase SericiteSample ID DDH Depth m Rock Type AlterationAG0005 LHDH17 705 QFP Sericite quartzTable A6: Description of the sample  AG0005125Figure A15: Thin section-XLP. Sample AG0006. Phenocrysts %Mineral % AlterationGroundmass % AlterationFigure A14: Microphotograph: Magnification 2X -XLP. Sample AG0006. Description and notes: The alteration has completelly altered the original texture. Quartz veins are cutting the sample. Sample ID DDH Depth m Rock Type AlterationAG0006 LHDH17 755  undeterminedTable A7: Description of the sample  AG0006126Figure A18: Microphotograph Magnification 2X -XLP. Sample AG0007.Figure A17: Thin section-XLP. Sample AG0007.Figure A16: Hand sample Photograph. Sample AG0007.Description and notes:  Rock with porphyric texture. Withe  and cream color . It is formed by phenocrysts  of feldespar (plagioclase)  altered (FK) ,  quartz is also present . The groundmass is formed by quartz, k-feldspar  and fine biotite. Quarz-anhydrite vein are present (0,3 to 0,6 cm).Phenocrysts 30 %Mineral % AlterationPLagioclase 25 SericiteQuartz 5Groundmass 70 % AlterationQuartz 50Biotite 10Feldspar 10 K-feldsparSample ID DDH Depth m Rock Type AlterationAG0007 LHDH17 1009 FPR Biotite K-FeldsparTable A8: Description of the sample  AG0007127Figure A19: Hand sample Photograph. Sample AG0008. Figure A20: Thin section-XLP. Sample AG0008.Description and notes: Rock with  porphyritic texture, light gray and pinkish color, consisting of plagioclase up to 3 mm, with  moderate replacement of k-feldspar  and  biotite phenocrysts up to 1.2 mm altered to chlorite and muscovite . The groundmass is aphanitic, formed by fine anhedral / subhedrals grains of quartz and feldpars  . Opaque minerals are pyrite. The rock is cut by irregular veinlets filled with quartz (2A).Phenocrysts 50 %Mineral % AlterationPLagioclase 43 K-feldsparBiotite 7Groundmass 50 % AlterationQuartz 35Feldspars 15Sample ID DDH Depth m Rock Type AlterationAG0008 LHDH17 1182 FGPCP K-feldsparTable A9: Description of the sample  AG0008128Figure A22: Thin section-XLP. Sample AG0009. Figure A21: Hand sample Photograph. Sample AG0009. Figure A23: Microphotograph Magnification 20X -XLP. Sample AG0009. Description and notes: Rock with porphyritic texture, white-cream color. It is formed by phenocrysts of anhedral  plagiolcasea up to 2mm totally altered to sericite. Very few quartz phenocrysts up to 2 mm subrounded. The groundmass is aphanitic and microfelsic formed by anhedral crystal of quartz and feldspar intensely altered to sericite.  It shows a microbreccia texture with blackish matrix with clasts of the same rock up to 5mm subangular. The matrix is hydrothermal formed by quartz pyrite and tourmaline.Phenocrysts 25 %Mineral % AlterationPlagioclse 23 SericiteQuartz 7Groundmass 75 % AlterationQuartzFeldspar SericiteSample ID DDH Depth m Rock Type AlterationAG0009 LHDH21 25 FPR Quartz SericiteTable A10: Description of the sample  AG0009129Figure A25: Thin section-XLP. Sample AG0010Figure A24: Hand sample Photograph. Sample AG0010Description and notes: Rock with porphyritic texture, withish-pale green in color. It is formed by   45% of subhedral-auhedral plagioclase phenocrysts (alterated to sericite) in an aphanitic microfelsic groundmass. Opaques are magnetite cpy and PyPhenocrysts 45 %Mineral % AlterationPLagioclase 40 Weak sericiteQuartz 5Groundmass 55 % AlterationQuartz 35plagioclase 15 SericiteBiotite 5Sample ID DDH Depth m Rock Type AlterationAG0010 LHDH21 260 BiPP Weak sericiteTable A11: Description of the sample  AG0010130Figure A26: Hand sample Photograph. Sample AG0011.Figure A27: Thin section-XLP. Sample AG0011.Description and notes: Rock with porphyritic texture. It is formed by 30 % of phenocrysts of plagioclase (intensely altered to sericite) and scarce quartz eyes.  The groundmass is formed by magmatic quartz and sericite microgranular. It presents two series of veins. The older  (type 2C)is 8mm wide formed by quartz and is being cut by 2 mm pyrite- quartz with sericite halo vein (type 8)Phenocrysts  30 %Mineral % AlterationPlagioclase 20 SericiteQuartz 10Groundmass 70 % AlterationQuartz 50Plagioclase 20 SericiteSample ID DDH Depth m Rock Type AlterationAG0011 LHDH21 342 FPR SericiteTable A12: Description of the sample  AG0011131Figure A29: Thin section-XLP. Sample AG0012.Figure A28: Hand sample Photograph. Sample AG0012. Figure A30: Microphotograph Magnification 5X -XLP. Sample AG0012. Phenocrysts 30 %Mineral % AlterationPlagioclase 25 SericiteQuartz 5Groundmass 70 % AlterationQuartz 40Plagioclase 30 SericiteDescription and notes: Rock with porphyritic texture, whiteish in color, formed by plagioclase phenocrystal up to 2.5mmSample ID DDH Depth m Rock Type AlterationAG0012 LHDH21 554 FPR Quartz SericiteTable A13: Description of the sample  AG0012132Figure A32: Thin section-XLP. Sample AG 0013. Figure A31. Hand sample Photograph. Sample AG 0013. Description and notes: Porphyric texture (45 Phenocrysts and 55 groundmass). It is formed by Phenocrysts of Plagioclase (euhedral -subhedral) up to 3mm, quartz and biotite. The groundmass is formed by quartz and plagioclase. It has a veinlet filled with quartz-pyrite with an alteration halo.Phenocrysts 45 %Mineral % AlterationPlagioclase 30 SericiteQuartz 8Biotite 7Groundmass 55 % AlterationPlagioclase 25 SericiteQuartz 30Sample ID DDH Depth m Rock Type AlterationAG0013 LHDH21 725 BPP Qartz SericiteTable A14: Description of the sample  AG0013133Figure A35: Microphotograph Magnification 2X -XLP. Sample AG0014.Figure A34: Thin section-XLP. Sample AG0014.Figure A33: Hand sample Photograph. Sample AG0014. Description and notes: Rock with medium phaneritic texture. It is formed by plagioclase euhedral to subhedral, biotite and quartz. Plagioclase are passing to k-feldspar and biotite is a common as alteration mineral.Mineral % AlterationPlagioclase 75 K-feldsparMafics minerals 15 BiotiteQuartz 10Sample ID DDH Depth m Rock Type AlterationAG0014 LHDH21 1016 Ga/Dio K-feldsparTable A15: Description of the sample  AG0014134Figure A37: Thin section-XLP. Sample AG0015.Figure A36: Hand sample Photograph . Sample AG0015.Sample ID DDH Depth m Rock Type AlterationAG0015 LHDH21 1141 Ga/Dio BiotiteDescription and notes: Rock with medium phaneritic texture. It is formed by euhedral to subhedral plagioclase, biotite replacing all the mafics minerals and quartz. Plagioclase are passing to k-feldspar and biotite is a common as alteration mineral.Mineral % AlterationPlagioclase 70 K-feldsparMafics minerals 20 BiotiteQuartz 10Table A16: Description of the sample  AG0015135Figure A39: Thin section-XLP. Sample AG0016. Figure A38: Hand sample Photograph . Sample AG0016.Description and notes: Rock with medium phaneritic texture. It is formed by euhedral to subhedral plagioclase, biotite replacing all the mafics minerals and quartz. Plagioclase are passing to k-feldspar and biotite is a common as alteration mineral. This samples was taken over a alteration halo. Sample ID DDH Depth m Rock Type AlterationAG0016 LHDH21 1230 Ga/DioMineral % AlterationPlagioclase 70 K-feldsparMafics minerals 20 BiotiteQuartz 10Table A17: Description of the sample  AG0016136Figure A42: Microphotograph Magnification 2X -XLP. Sample AG0018.Figure A41: Thin section-XLP. Sample AG0018Figure A40: Hand sample Photograph. Sample AG0018Description and notes: Rock with medium phaneritic texture, dark gray to blackish in color. It is formed by plagioclases from 1 to 4 mm partially altered to sericite. Mafics minerals are replaced by fine secondary biotite. The rock is cut by anhydrite vein.Mineral % AlterationPlagioclase 70 SericiteMafics 24 BiotiteQuartzSample ID DDH Depth m Rock Type AlterationAG0018 LHDH21 1399 Ga/DioTable A18: Description of the sample  AG0018137Figure A45: Microphotograph Magnification 2X -XLP. Sample AG0019. Figure A44: Thin section-XLP. Sample AG0019Figure A43: Hand sample Photograph . Sample AG0019Description and notes: Rock with crowded porphyritic texture, creamish to light green in color. It is formed by 50 % of plagioclase phenocrysts up to 3mm moderately altered to k-feldspar. The groundmass is   micro felsic composition.Phenocrysts 50 %Mineral % AlterationPlagioclase 45 K-feldsparQuartzGroundmass 50 % AlterationPlagioclase 20Quartz 30Sample ID DDH Depth m Rock Type AlterationAG0019 LHDH28 679 FGPCP K-feldsparTable A19: Description of the sample  AG0019138Figure A46: Thin section-XLP. Sample  AG0020. Phenocrysts %Mineral % AlterationGroundmass % AlterationDescription and notes: The most conspicuous feature of this sample is the veins. It shows quartz anhydrite vein with an alteration halo of   7mm formed by sericite an chalcopyrite cut by irregular quartz veinlet.Sample ID DDH Depth m Rock Type AlterationAG0020 LHDH28 779    UndeterminedTable A20: Description of the sample  AG0020139Figure A49: Microphotograph. Magnification 2X -XLP. Sample AG0021.Figure A48: Thin section-XLP. Sample AG0021.Figure A47: Hand sample Photograph. Sample AG0021.Description and notes: Rock with porphyritic texture, grey-greenish in color. It is formed by plagioclase up to 2,5 mm replaced by sericite. It also presents biotite phenocryts. The groundmass in microphelsic composition formed by anhedral crystals of qurtz and plagioclase. It shows an anhydrite vein with an sericitic halo.Phenocrysts 45 %Mineral % AlterationPlagioclase 35 SericiteQuartz 5Biotite 5 weak chloriteGroundmass 55 % AlterationPLagioclase 30 SericiteBiotite 10 weak chloriteSample ID DDH Depth m Rock Type AlterationAG0021 LHDH28 947 FGPCP SericiteTable A21: Description of the sample  AG0021140Figure A52: Microphotograph.  Magnification 2X -XLP. Sample AG0022.Figure A51: Thin section-XLP. Sample AG0022.Figure A50: Hand sample Photograph . Sample AG0022.Description and notes: Rock with porphyritic texture, light grey colour. It is formed by phenocrysts of quartz   and plagioclase   altered to sericite  . Abundant quartz phenocrysts up to 3.3 mm with partial magmatic resorption. The groundmass is aphanitic formed by anhedral crystal of qz-sericite < 0.1mm. Phenocrysts 35 %Mineral % AlterationPLagioclase 20 SericiteQuartz 15Groundmass 65 % AlterationPlagioclase 35 SericiteQuartz 30Sample ID DDH Depth m Rock Type AlterationAG0022 Outcrop QFP SericiteTable A22: Description of the sample  AG0022141Figure A54: Thin section-XLP. Sample AG0023.Figure A53: Outcrop Photograph. Sample AG0023. Phenocrysts %Mineral % AlterationPlagioclase 20 Waek sericiteQuartz 30K-feldspar 35Biotite 10 Weak chloritePyroxene 5Rock with phaneritic texture, medium to coarse grain. It is formed by potassic feldspar, plagioclase, quartz, biotite and pyroxenes. The plagioclases show weak sericitic alteration whereas biotites show weak chlorotic alteration. 441325 E-6864771 N-UTM-19S.Sample ID outcrop Rock Type AlterationAG0023 GRN Table A23: Description of the sample  AG0023142Figure A57: Microphotograph. Magnification 2X -XLP. Samples AG0024 and AG0025.Figure A56: Thin section-XLP. Samples AG0024 and AG0025.Figure A55: Hand sample Photograph . Samples AG0024 and AG0025.Description and notes: Rock with porphyritic texture, light green in color. It is formed by euhedral to subhedral plagioclase phenocrysts up to 2mm (with replacement of sericite). It shows 2 set of veinlet of 2 mm filed with quartz (vein type: 2 D)40 %Mineral % AlterationPlagioclase 32 SericiteQuartz 5Biotite 3Groundmass 60 % AlterationPlagioclase 20Quartz 40Sample ID Outcrop Rock Type AlterationAG0024-AG0025 BiPP SericiteTable A24: Description of the sample  AG0024 and AG0025143Figure A58: Thin section-XLP. Sample AG0026.Description and notes: Medium grain phaneritic texture. Hypidiomorphic, all minerals are subhedral. 443208 E- 6865700 N-UTM-19SSample ID outcrop Depth m Rock Type AlterationAG0026 Ga/DioPhenocrystsMineral % AlterationPlagioclase 73Biotite 10Amphibole 5Piroxene 5Epidote 5Table A25: Description of the sample  AG0026144Figure A59: Hand sample Photograph . Sample AG0027. Description and notes: Rock with porphyritic texture formed by 30% of phenocryst of plagioclase up to 4mm and 70 % of groundmass composed by quartz and plagioclase with a grain size average about 0.25 mm. 442853 E-6863784 N-UTM-19SPhenocrysts 30 %Mineral % AlterationQuartz 20Plagioclae 10 SericiteGroundmass 70 % AlterationQuartz 50Plagioclase 20 SericiteSample ID outcrop Rock Type AlterationAG0027 FPR SericitieTable A26: Description of the sample  AG0027145Figure A61: Thin section-XLP. Sample AG0028.Figure A60: Hand sample Photograph . Sample AG0028.Description and notes: Rock with porphyritic texture, light grey in colour. It is formed by phenocrysts of quartz (<1,5mm) and plagioclase totally altered to sericite (texture has been completely obliterated). The groundmass is aphanitic formed by anhedral crystal of quartz and sericite (< 0,2-0,5mm).  Quartz/pyrite vein (tyoe 8) cut the rock.Phenocrysts 35 %Mineral % AlterationPagioclase 25 SericiteQuartz 10Groundmass 65 % AlterationQuartz 40Plagioclase 25 SericiteSample ID DDH Depth m Rock Type AlterationAG0028 LHDH28 490 FPR SericiteTable A27: Description of the sample  AG0028146Figure A63: Thin section-XLP. Sample AG0029.Figure A62: Hand sample Photograph. Sample AG0029.Phenocrysts 35 %Mineral % AlterationPlagioclase 25 SericiteQuartz 10Groundmass % AlterationQuartz 40PLagioclase 25 SericiteSample ID DDH Depth m Rock Type AlterationAG0029 LHDH29 521   FPR SericiteDescription and notes: Rock with porphyritic texture, light grey in colour. It is formed by phenocrysts of quartz (<1,5mm) and plagioclase totally altered to sericite (texture has been completely obliterated). The groundmass is aphanitic formed by anhedral crystal of quartz and sericite (< 0,2-0,5mm). Table A28: Description of the sample  AG0029147Figure A65: Thin section-XLP. Sample AG200. Figure A64: Hand sample Photograph. Sample AG200. Figure A66: Microphotograph. Magnification 10X -XLP. Sample AG200. Description and notes: Breccia cemented by anhydrite chalcopyrite and traces of molybdenite and bornite. The clasts are granites.Cement Composition %Anhydrite 65Chalcopyrite 25Molybdenite 8Bornite 2Clasts composition %GRN 100Sample ID DDH Depth m Rock Type Cement %AG200 LHDH34 920 CBX 15Table A29: Description of the sample  AG200148Figure A68: Thin section-XLP. Sample AG201.  Figure A67: Hand sample Photograph. Sample AG201. Figure A69: Microphotograph: Magnification 2X -XLP. Sample AG201. Description and notes: Jig-saw breccia. Strong phillic alteration. Cement Composition %Pyrite 80Tourmaline 10Quartz 10Clasts composition %FPR 100Sample ID DDH Depth m Rock Type Cement %AG201 LHDH50 93 CBX 18Table A30: Description of the sample  AG201149Figure A71: Thin section-XLP. Sample AG202. Figure A70: Hand sample Photograph . Sample AG202. Figure A72: Microphotograph. Magnification 20X -XLP. Sample AG202. Description and notes:  CBX with 25 % of hysrothermal cement. Clasts are angulous. Cement Composition %Biotite 40Chalcopyrite 20Magnetite 20Pyrite 15Anhydrite 5Clasts composition %FPR 80Ga/Dio 20Sample ID DDH Depth m Rock Type Cement %AG202 LHDH50 679 CBX 25Table A31: Description of the sample  AG202150Figure A74: Thin section-XLP. ample AG 203.Figure A 73: Hand sample Photograph. Sample AG 203.Figure A75: Microphotograph. Magnification 2X -XLP. ample AG 203.Description and notes: Biotite rich matrix. Cement Composition %Biotite 60Chalcopyrite 15Magnetite 15Pyrite 10Clasts composition %GRN 65FPR 35Sample ID DDH Depth m Rock Type Cement %AG203 LHDH26 958 CBX 17Table A32: Description of the sample  AG203151Figure A77: Thin section-XLP. Sample AG204.  Figure A78:  Microphotograph. Magnification 2X -XLP. Sample AG204.  Description and notes: Matrix-rich breccia cemented by Chalcopyrite, magnetite and pyrite. Cement Composition %Chalcopyrite 60Magnetite 25Pyrite 15Clasts composition %FPR 90AND 10Sample ID DDH Depth m Rock Type Cement %AG204 LHDH30 741 CBX 17Figure A76: Hand sample Photograph. Sample AG204. Table A33: Description of the sample  AG204152Figure A80: Thin section-XLP. Sample AG205.  Figure A79: Hand sample Photograph. Sample AG205.  Figure A81: Microphotograph. Magnification 2X -XLP. Sample AG205. Description and notes: Cement-rich breccia. Hematite-magnetite-chalcopyrite vein cut the rock.Cement Composition %Magnetite 40Hematite 25Chalcopyrite 20Pyrite 15Clasts composition %QFP 60FPR 40Sample ID DDH Depth m Rock Type Cement %AG205 LHDH72 401 CBX 9Table A34: Description of the sample  AG205153Figure A83: Thin section-XLP. Sample AG206. Figure A82: Hand sample Photograph. Sample AG206. Figure A84: Microphotograph. Magnification 2X -XLP. Sample AG206. Description and notes: Matrix-rich breccia cemented by magnetite-pyrite-chalcopyriteCement Composition %Pyrite 45Magnetite 35Chalcopyrite 20Clasts composition %QFP 55FPR 45Sample ID DDH Depth m Rock Type Cement %AG206 LHDH21 320 MRBX 3Table A35: Description of the sample  AG206154Figure A86: Thin section-XLP. Sample AG207. Figure A85: Hand sample  Photograph. Sample AG207. Figure A87: Microphotograph. Magnification 2X -XLP. Sample AG207. Description and notes: Cement-rich breccia cemented by magnetite-biotite-chalcopyrite-anhydrite.Cement Composition % Magnetite 40 Biotite  30Chalcopyrite 15Anhydrite 15Clasts composition %FPR 90QFP 10Sample ID DDH Depth m Rock Type Cement %AG207 LHDH22 720 CBX 7Table A36: Description of the sample  AG207155Figure A89: Thin section-XLP. Sample AG208.  Figure A88: Hand sample Photograph. Sample AG208.  Figure A90: Microphotograph. Magnification 2X -XLP. Sample AG208.  Description and notes:  Cement-rich breccia cemented by magnetite-anhydrite-chalcopyrite-anhydrite.Cement Composition %Magnetite 60Anhydrite 20Chalcopyrite 20Clasts composition %FPR 25FGPCP 25GRN 15AND 15QFP 10Sample ID DDH Depth m Rock Type Cement %AG208 LHDH50 860 MRBX 3Table A37: Description of the sample  AG208156Figure A92: Thin section-XLP. Sample AG210. Figure A91: Hand sample Photograph. Sample AG210. Description and notes: Matrix rich breccia cemented by magnetite, hematite, pyrite and chalcopyrite. Sericite and chlorite are the dominants alterationminerals. Figure A93: Microphotograph. Magnification 10X -XLP. Sample AG210. Cement Composition %Magnetite 50Hematite 25Chalcopyrite 15Pyrite 20Clasts composition %FPR 100Sample ID DDH Depth m Rock Type Cement %AG210 LHDH24 380 MRBX 9Table A38: Description of the sample  AG210157Figure A94: Hand sample Photograph. Sample AG211. Figure A95: Thin section-XLP. Sample AG211.Cement Composition %Magetite 50Hematite 25Chalcopyrite 15Pyrite 10Clasts composition %FPR 100Sample ID DDH Depth m Rock Type Cement %AG211 LHDH13 358 MRBX 13Description and notes: Matrix rich breccia cemented by magnetite, hematite, pyrite and chalcopyrite. Table A39: Description of the sample  AG211158Figure A97: Thin section-XLP. Sample AG217.Figure A96: Hand sample Photograph. Sample AG217.Cement Composition %Quartz 90Chalcopyrite 5Pyrite 5Figure A98: Cobalt nitrite staining: Yellow stain indicates K-feldpar.Sample AG217.Description and notes:  Biotite replacement in the dark side and K-feldspar replacement in the white side.  The dark side is diorite and the white seem to be granite. The presence of K-feldspar is also confirmed by cobalt nitrite staining. Clasts composition %Gabbro/Diorite 50Granite 50Sample ID DDH Depth m Rock Type Cement %AG217 LHDH21 1330 MRBX 8Table A40: Description of the sample  AG217159Appendix B:   Whole-rock geochemistry160Sample ID Analyte HOLE-ID DEPTH UTM W84E 19S UTM W84N 19S ALT DEMAG0001 Drill Core LHDH17 157AG0002 Drill Core LHDH17 439AG0003 Drill Core LHDH17 358AG0005 Drill Core LHDH17 705AG0008 Drill Core LHDH17 1182AG0010 Drill Core LHDH21 260AG0012 Drill Core LHDH21 554AG0013 Drill Core LHDH21 725AG0015 Drill Core LHDH21 1141AG0020 Drill Core LHDH28 779AG0022 Outcrop 442795 6864581 4674AG0023 Outcrop 441325 6864771 4839AG0024 Outcrop 442340 6864630 4744AG0025 Outcrop 442822 6864603 4698AG0026 Outcrop 443208 6865700 3564AG0028 Drill Core LHDH28 496AG121 Outcrop 442821 6864527 4712AG122 Outcrop 442821 6864527 4712AG123 Outcrop 442821 6864527 4712AG125 Outcrop 442821 6864527 4712AG127 Outcrop 442822 6864601 4677AG128 Outcrop 442790 6864601 4674AG129 Outcrop 442702 6864538 4676AG130 Outcrop 442705 6864538 4676AG131 Outcrop 442688 6864549 4675AG132 Outcrop 442522 6864630 4575AG133 Outcrop 442361 6864635 4676Table B1:  Location for  geochemical  samples.161Sample and analytical methodsTwenty-seven samples from all the lithologies were selected for major, trace and rare-earth ele-ment geochemistry. Representative samples were selected from exploration drill core and outcrops. Samples were prepared for processing by cutting away weathered edges with a diamond embedded saw and then were individually packed in a plastic sample bag and given a unique sample name.The Los Helados samples were analyzed for whole-rock geochemistry at ACME Labs Vancouver. Major oxides were analyzed by X-ray fluorescence (XRF) with a Lithium metaborate fusion finish. Trace elements were analyzed by inductively coupled plasma mass spectroscopy (ICP-MS) with a lithium metaborate/tetraborate fusion finish. Nitric acid digestion was used for rare earth (REE) and refractory element results. Aqua Regia digestion was used for precious and base metal resultsSample preparation and analytical procedures (Taken from Bureau Veritas Minerals 2015)Procedure Code Description CRU80 Crush to 80% passing 10 mesh PULCB Pulverize Ceramic Bowl PULSW Extra wash with sand between each sample in pulverizer LF600 XRF Whole Rock Extended & ICP-MS Trace Elements Table D1:  Acme codes used for Los Helados samples162Method LF700Sample Unit Analyte Wgt SiO2 Al2O3 Fe2O3 CaO MgO Na2O K2O MnO TiO2 P2O5 Cr2O3 Ba LOI CuUnit KG % % % % % % % % % % % % % %AG0001 FP Drill Core 0.25 64.2 12.55 9.62 0.77 0.31 0.06 3.78 <0.01 0.31 0.15 <0.001 0.02 7.4 0.23AG0002 BPP Drill Core 0.41 63.3 16.63 6.21 0.78 1.32 3.89 2.68 0.05 0.44 0.18 <0.001 0.04 3.96 0.11AG0003 FP Drill Core 0.36 68.7 12.82 4.7 1.69 0.47 0.09 4.11 0.02 0.35 0.08 <0.001 0.03 6.13 0.4AG0005 QFP Drill Core 0.26 63.2 15.07 4.32 2.04 0.84 3.37 4.66 <0.01 0.37 0.14 <0.001 0.09 4.61 0.9AG0008 FGPCP Drill Core 0.2 66.2 16.14 1.06 3.05 0.9 5 4.04 0.01 0.39 0.14 <0.001 0.1 3.02 0.15AG0010 BiPP Drill Core 0.27 60.4 15.61 5.35 2.49 1.32 3.21 3.69 0.02 0.43 0.15 <0.001 0.04 6.47 0.29AG0012 FP Drill Core 0.3 61.1 15.79 4.37 2.37 1.14 3.1 3.62 0.03 0.41 0.16 <0.001 0.04 6.96 0.88AG0013 BPP Drill Core 0.25 61.5 16.08 1.86 3.23 1.1 5.07 3.25 0.01 0.49 0.18 <0.001 0.07 6.49 0.16AG0015 TON Drill Core 0.23 46.1 18.67 7.66 7.99 4.79 3.7 2.98 0.03 1 0.15 0.016 0.02 4.06 0.42AG0020 INDET Drill Core 0.29 63 15.42 2.25 2.88 1.58 5.58 2.53 0.02 0.79 0.34 <0.001 0.03 5.18 0.51AG0022 QFP Rock 0.79 63.9 15.63 2.08 2.92 0.59 0.35 4.63 <0.01 0.39 0.04 <0.001 0.07 7.84 0.02AG0023 GRN Rock 0.63 69.9 14.8 2.77 1.96 0.77 3.95 3.96 0.07 0.4 0.11 <0.001 0.07 1.1 <0.01AG0024 BiPP Rock 0.84 64.7 16.77 3.61 1.51 1.14 6.04 1.92 0.02 0.45 0.15 <0.001 0.09 3.61 <0.01AG0025 BiPP Rock 0.99 64 16.56 3.29 1.92 1.01 4.87 3.43 0.02 0.44 0.14 <0.001 0.15 4.18 <0.01AG0026 TON Rock 0.93 50.8 17.75 10.45 9.09 4.73 3.53 0.55 0.16 1.35 0.35 0.002 0.02 1.16 <0.01AG0028 FP Drill Core 0.32 70.3 13.45 2.32 1.27 0.76 1.62 5.28 <0.01 0.38 0.1 <0.001 0.07 3.66 0.5AG121 BiPP Drill Core 3.24 66.3 14.02 3.94 1.72 1.26 1.62 3.37 0.02 0.38 0.04 <0.001 0.08 5.13 0.09AG122 GRN Drill Core 3.10 72.5 13.15 2.70 0.67 0.68 1.06 3.64 0.01 0.36 0.05 <0.001 0.14 3.71 0.01AG123 BiPP Drill Core 2.66 71.9 14.03 2.54 0.85 0.56 0.16 4.22 <0.01 0.40 0.05 <0.001 0.11 4.13 0.02AG125 BiPP Drill Core 2.94 61.0 15.25 7.65 1.81 1.09 5.26 1.95 0.02 0.38 0.05 <0.001 0.04 4.84 0.06AG127 BiPP Drill Core 2.54 66.8 16.22 1.95 1.66 0.46 0.40 4.68 <0.01 0.43 0.11 0.003 0.10 5.41 <0.01AG128 QFP Drill Core 3.90 61.6 14.92 4.96 2.44 1.52 4.85 1.97 0.02 0.37 0.04 <0.001 0.02 6.12 0.20AG129 QFP Drill Core 3.24 59.0 12.74 6.59 4.16 0.71 0.16 3.91 <0.01 0.32 0.05 <0.001 0.06 8.03 0.15AG130 INDET Drill Core 0.72 22.0 5.55 42.92 0.89 0.02 0.13 1.29 <0.01 0.08 0.09 <0.001 0.08 26.19 0.03AG131 INDET Drill Core 4.26 65.0 16.57 3.51 1.70 1.36 5.61 2.00 0.04 0.44 0.07 <0.001 0.07 3.84 0.09AG132 BiPP Drill Core 2.64 61.8 17.42 5.15 1.27 0.85 4.30 2.92 <0.01 0.55 0.17 <0.001 0.05 4.38 0.09Table B2:  Geochemistry results.163Method LF700 TC000 LF100Sample Ni Pb SO3 Sr V2O5 Zn Zr SUM TOT/C TOT/S Ba Be Co Cs Ga Hf Nb Rb Sn Sr% % % % % % % % % % PPM PPM PPM PPM PPM PPM PPM PPM PPM PPMAG0001 <0.01 <0.01 0.095 0.004 0.006 <0.001 0.014 99.53 <0.02 7.31 176 3 30.7 1.4 13.4 4.6 7.9 89.8 14 29.3AG0002 <0.01 <0.01 0.099 0.106 0.012 0.022 0.013 99.85 0.21 0.4 376 2 1.6 1.3 20.3 3.8 4.2 64.4 4 1049.2AG0003 <0.01 <0.01 0.371 0.007 0.006 <0.001 0.015 100.05 0.04 2.97 282 1 12 1.4 22.6 4.7 7.9 90.7 13 67AG0005 <0.01 <0.01 0.159 0.036 0.006 0.002 0.012 100.08 0.1 1.93 961 1 4.5 0.3 21.7 3.7 4.4 67.4 6 410.4AG0008 <0.01 <0.01 0.13 0.078 0.006 0.002 0.008 100.5 0.07 0.98 1015 3 2.1 0.5 18.7 3.8 3.9 41.1 1 784.9AG0010 <0.01 <0.01 0.267 0.02 0.009 0.006 0.011 99.88 0.17 3.17 367 <1 0.5 1.2 22 3.5 3.8 89.3 5 152AG0012 <0.01 <0.01 0.34 0.02 0.009 0.01 0.01 100.55 0.05 2.12 334 4 6.8 1.9 17.7 3.6 3.8 73.6 4 206.6AG0013 <0.01 <0.01 0.342 0.046 0.01 0.002 0.014 99.93 0.06 2.09 712 1 2.4 0.6 18.5 3.8 4.2 56.2 3 513.1AG0015 <0.01 <0.01 2.346 0.042 0.039 0.005 0.003 100.15 <0.02 2.13 202 <1 16.9 1.1 20.5 1.9 4.7 95.2 2 488.7AG0020 <0.01 <0.01 0.25 0.031 0.014 0.004 0.016 100.55 0.05 1.87 345 2 2.9 0.6 12.5 4.4 8.1 57.7 5 263.4AG0022 <0.01 <0.01 1.277 0.073 0.006 <0.001 0.013 99.88 <0.02 1.88 766 4 1.1 3.5 23.5 4.1 4.6 154.6 6 761.1AG0023 <0.01 <0.01 <0.002 0.029 0.004 0.001 0.017 99.87 <0.02 <0.02 743 4 3.9 2.8 15.7 5.4 13.8 176.1 2 244.1AG0024 <0.01 <0.01 0.04 0.053 0.009 0.007 0.013 100.14 <0.02 0.6 866 <1 5.5 0.3 22 4.3 4.1 43.6 2 573.8AG0025 <0.01 <0.01 0.072 0.071 0.01 0.006 0.014 100.24 <0.02 0.69 1610 4 4.4 0.5 22.2 4.2 4 63.2 2 683.8AG0026 <0.01 <0.01 <0.002 0.043 0.05 0.009 <0.002 100.01 <0.02 0.03 238 3 30.5 0.5 19.4 1.6 2.1 10.5 <1 571.2AG0028 <0.01 <0.01 0.182 0.016 0.009 0.002 0.015 100.07 0.09 1.13 743 4 2.1 0.7 11.7 4.5 7.8 81.6 5 120.4AG121 <0.01 <0.01 1.237 0.021 0.008 0.007 0.019 99.35 <0.02 1.12 764 3 3.7 2.6 14.6 5.3 9.6 110.6 7 165.4AG122 <0.01 <0.01 0.557 0.012 0.007 0.004 0.015 99.32 <0.02 0.75 1309 1 1.6 2.8 13.3 4.8 9.7 104.0 5 110.4AG123 <0.01 0.01 0.779 0.013 0.006 0.001 0.020 99.81 <0.02 0.90 1055 4 1.6 3.1 16.8 5.5 9.3 124.9 6 135.4AG125 <0.01 <0.01 0.463 0.035 0.011 0.005 0.012 99.94 <0.02 1.04 360 2 3.1 0.4 22.1 3.5 3.7 63.2 7 341.2AG127 <0.01 <0.01 1.250 0.037 0.012 0.001 0.013 99.58 <0.02 1.22 988 <1 1.1 0.9 25.1 4.5 4.8 147.2 8 384.8AG128 <0.01 <0.01 0.519 0.017 0.008 0.006 0.014 99.70 <0.02 1.51 154 <1 2.4 1.7 17.8 3.7 4.3 64.4 4 155.7AG129 <0.01 <0.01 3.525 0.012 0.009 0.003 0.010 99.50 <0.02 3.04 541 <1 3.3 2.5 21.1 2.9 3.4 125.4 13 184.5AG130 <0.01 0.01 0.356 0.040 <0.002 <0.001 <0.002 99.76 <0.02 36.29 819 <1 28.9 0.2 3.2 0.7 0.8 20.8 7 461.5AG131 <0.01 <0.01 0.380 0.055 0.010 0.010 0.015 100.78 <0.02 0.76 636 3 6.2 0.7 21.6 3.6 4.4 47.1 2 562.7AG132 <0.01 <0.01 0.498 0.046 0.012 0.003 0.012 99.55 <0.02 1.00 469 4 5.6 0.3 22.3 4.3 3.9 83.6 3 435.9AG133 <0.01 <0.01 0.384 0.078 0.011 0.008 0.014 101.31 <0.02 0.80 1003 5 4.8 1.0 21.3 4.0 4.0 38.1 2 759.2164Method LF100Sample Ta Th U V W Zr Y La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb LuPPM PPM PPM PPM PPM PPM PPM PPM PPM PPM PPM PPM PPM PPM PPM PPM PPM PPM PPM PPM PPMAG0001 0.6 7.1 0.9 55 4.9 184.5 6.2 30.2 55.8 5.87 19.3 2.95 0.74 1.82 0.22 1.16 0.2 0.62 0.12 0.79 0.12AG0002 0.2 1.9 1.1 73 2.4 149.4 4.5 21.9 43.6 5.1 19.1 2.92 0.75 1.82 0.2 0.93 0.15 0.43 0.07 0.37 0.04AG0003 0.8 8.2 1.5 46 5.3 186.8 9 24.1 45.8 4.81 16.7 2.64 0.72 2.31 0.29 1.77 0.32 0.99 0.15 1.17 0.18AG0005 0.3 2.7 0.9 55 3 143.2 4.4 19.8 37.5 4.36 15.9 2.38 0.68 1.56 0.17 0.8 0.16 0.42 0.05 0.38 0.06AG0008 0.2 2 0.4 49 2.5 145.8 4.2 20.1 40.6 4.76 17.6 2.72 0.67 1.57 0.19 0.93 0.14 0.37 0.06 0.41 0.05AG0010 0.3 2.6 1.2 53 1.3 144.8 4.2 23 43.6 5.09 19 2.77 0.76 1.78 0.19 0.9 0.14 0.4 0.06 0.39 0.05AG0012 0.2 2 1.4 53 3.4 146 4.6 24.4 48.4 5.74 21.9 3.32 0.88 2.04 0.23 1.11 0.16 0.39 0.06 0.39 0.06AG0013 0.2 2.2 0.8 59 3.6 135.3 4.3 21.2 42.8 4.96 19.5 2.87 0.77 1.88 0.19 0.83 0.13 0.46 0.05 0.42 0.05AG0015 0.2 1 0.3 224 <0.5 79.4 14.5 15.3 30 3.62 15.1 3 1.11 3.08 0.46 2.64 0.49 1.6 0.22 1.26 0.19AG0020 0.6 5.8 2 81 8.1 193.6 17.1 23.9 49.8 5.84 23.5 4.41 1.28 3.84 0.55 3.15 0.58 1.79 0.26 1.64 0.26AG0022 0.3 2.3 0.8 43 1.2 158.9 2.8 15.5 28.3 2.99 10.9 1.67 0.33 0.88 0.09 0.54 0.08 0.29 0.04 0.31 0.05AG0023 2 17.7 2 32 0.6 189.1 35.9 42 83.6 9.18 33.7 6.67 1.06 6.3 0.98 6.04 1.24 3.66 0.59 4.07 0.6AG0024 0.3 2.2 0.9 60 0.7 160.2 2.8 14.1 24.5 2.6 9.4 1.46 0.38 1.05 0.12 0.71 0.12 0.33 0.03 0.37 0.04AG0025 0.3 2.3 0.9 47 0.7 160.7 2.9 15 27.5 2.98 10.2 1.7 0.47 1.14 0.14 0.72 0.11 0.35 0.04 0.27 0.05AG0026 0.2 0.8 <0.1 294 <0.5 67.5 15.9 10.3 23.7 3.2 15.7 3.34 1.36 3.56 0.55 3.2 0.61 1.63 0.24 1.66 0.24AG0028 0.7 9 1.3 42 4 185.4 12.8 25.3 47.4 4.98 17.5 2.78 0.7 2.42 0.35 2.21 0.42 1.44 0.22 1.55 0.24AG121 0.7 7.1 2.1 37 1.1 206.4 15.1 28.0 53.7 5.77 20.1 3.29 0.74 2.78 0.44 2.37 0.49 1.74 0.25 1.84 0.29AG122 0.8 15.1 1.6 36 2.1 181.4 19.6 38.4 76.4 8.04 27.1 4.26 0.70 3.40 0.52 2.91 0.63 2.10 0.34 2.15 0.35AG123 0.8 7.7 1.8 30 1.8 205.2 10.5 23.7 47.4 5.07 18.7 2.35 0.51 1.85 0.28 1.48 0.38 1.23 0.23 1.56 0.24AG125 0.2 2.9 1.7 57 0.8 136.7 5.3 20.6 40.4 4.53 16.8 2.33 0.60 1.54 0.18 0.86 0.17 0.47 0.06 0.37 0.07AG127 0.3 2.6 0.8 52 1.5 156.4 3.1 21.5 41.2 4.02 13.7 1.75 0.35 0.92 0.11 0.58 0.10 0.33 0.04 0.33 0.05AG128 0.3 3.3 1.0 41 0.9 139.6 4.4 21.0 40.3 4.66 17.1 2.67 0.72 1.51 0.20 0.83 0.15 0.41 0.06 0.37 0.06AG129 0.2 2.7 1.1 42 1.5 108.6 3.4 19.5 37.9 4.29 14.6 1.66 0.44 1.10 0.12 0.58 0.14 0.35 0.05 0.35 0.05AG130 <0.1 1.3 0.3 18 1.0 26.9 0.9 9.6 17.3 2.10 9.0 1.09 0.21 0.40 0.03 0.13 0.03 0.09 <0.01 0.07 0.01AG131 0.2 2.2 1.3 49 <0.5 138.9 2.7 12.6 23.8 2.73 11.2 1.62 0.48 1.06 0.13 0.66 0.12 0.30 0.05 0.28 0.05AG132 0.3 3.5 1.9 75 0.8 163.3 7.0 23.8 48.8 5.77 21.7 3.30 0.90 2.12 0.26 1.43 0.25 0.73 0.10 0.72 0.10AG133 0.3 2.4 1.0 55 <0.5 153.0 3.4 16.6 31.0 3.16 11.4 1.71 0.51 1.26 0.14 0.76 0.12 0.37 0.06 0.40 0.06165Method AQ200Sample Mo Cu Pb Zn Ni As Cd Sb Bi Ag Au Hg Tl SePPM PPM PPM PPM PPM PPM PPM PPM PPM PPM PPB PPM PPM PPMAG0001 20.8 2385.1 6.4 15 6.3 162 <0.1 0.1 0.4 0.8 192.4 0.11 <0.1 3.9AG0002 9.2 1153.3 0.9 120 3.1 2.8 0.1 <0.1 <0.1 0.3 38 <0.01 0.1 <0.5AG0003 1.9 3971 3.9 8 3.8 <0.5 <0.1 <0.1 0.1 1 1308.8 0.04 <0.1 4.4AG0005 6.6 9106.7 3.7 32 5.4 <0.5 <0.1 <0.1 <0.1 2.9 222.7 <0.01 <0.1 4.5AG0008 27.5 1535.6 5.5 35 2.7 0.8 <0.1 <0.1 <0.1 0.7 38.2 <0.01 <0.1 0.8AG0010 3.6 2809 3.6 55 1.5 <0.5 <0.1 <0.1 <0.1 0.7 43.1 <0.01 0.1 1.4AG0012 152.7 8623.5 32.7 87 6.2 5.8 0.1 0.2 0.2 2 69.7 0.04 <0.1 3.6AG0013 4.4 1627.8 3.5 23 3.9 <0.5 <0.1 <0.1 <0.1 0.6 24.8 0.01 0.1 2AG0015 2.8 4252.4 3.5 50 53.8 <0.5 <0.1 <0.1 0.4 4 81.4 <0.01 0.5 3.1AG0020 4 4959.8 3.2 30 9.6 <0.5 <0.1 0.1 <0.1 1.3 99.1 0.03 0.2 3AG0022 11.8 222.8 13.6 9 0.6 3 <0.1 <0.1 0.2 0.5 46 0.03 0.1 0.9AG0023 1.3 1.9 5 24 0.9 <0.5 0.1 <0.1 <0.1 <0.1 <0.5 <0.01 <0.1 <0.5AG0024 2.1 53.6 6.5 55 2 1.1 <0.1 <0.1 <0.1 0.4 48.1 <0.01 <0.1 <0.5AG0025 2.9 86.3 7.6 54 2.2 1.6 0.1 <0.1 0.2 1.2 155.9 <0.01 <0.1 <0.5AG0026 0.8 65.5 4.1 54 7.1 1.2 <0.1 <0.1 <0.1 <0.1 1.6 <0.01 <0.1 <0.5AG0028 12.2 4899.4 2.2 19 2.4 3 <0.1 <0.1 <0.1 1.3 235.9 0.04 <0.1 3.3AG121 7.3 896.6 3.9 54 3.4 3.0 <0.1 <0.1 0.2 0.4 9.0 0.01 <0.1 <0.5AG122 18.0 106.5 6.6 21 1.2 5.0 <0.1 0.2 0.2 0.4 24.3 0.17 <0.1 <0.5AG123 4.0 187.3 3.9 4 0.8 3.5 <0.1 <0.1 0.5 0.5 43.7 0.04 <0.1 <0.5AG125 4.6 552.6 2.8 39 3.3 2.8 <0.1 <0.1 <0.1 0.2 29.9 0.01 <0.1 <0.5AG127 5.2 44.7 2.1 7 0.2 0.7 <0.1 <0.1 0.2 0.1 52.0 0.02 <0.1 1.1AG128 5.9 2009.3 3.4 54 1.0 1.4 <0.1 <0.1 <0.1 0.3 23.4 <0.01 <0.1 <0.5AG129 12.0 1551.6 2.4 17 0.9 36.7 <0.1 0.8 0.1 0.9 198.9 0.04 0.2 1.9AG130 4.0 365.8 16.4 16 2.9 1.2 <0.1 0.5 1.0 10.6 577.2 2.31 <0.1 37.4AG131 2.5 855.4 11.4 83 2.3 6.1 <0.1 <0.1 0.1 1.2 71.4 0.07 <0.1 <0.5AG132 2.7 905.9 1.1 17 2.0 3.4 <0.1 <0.1 <0.1 0.3 72.3 0.02 <0.1 <0.5AG133 1.2 128.6 6.6 61 2.0 0.7 <0.1 <0.1 <0.1 0.6 94.8 0.01 <0.1 <0.5166Appendix C:   U/Pb Zircon geochronology167 Appendix C: U/Pb Zircon geochronology sample preparation, analytical methods and data. CA-TIMS procedures were provided by the Pacific Centre for Isotopic and Geochemical Re-search. Minor changes have been made to the text. A similar decription on of this procedure can also be found in texts such as Mundil et al. (2004), Mattinson (2005) and Scoates and Friedman (2008).Chemical Abrasion Procedures, grain dissolution and analytical methods: After rock samples have undergone standard mineral separation procedures zircons are hand-picked in alcohol.  The clearest, crack- and inclusion-free grains are selected, photographed and then annealed in quartz glass crucibles at 900˚C for 60 hours.  Annealed grains are transferred into 3.5 mL PFA screw top beakers, ultrapure HF (up to 50% strength, 500 mL) and HNO3 (up to 14 N, 50 mL) are added and caps are closed finger tight.  The beakers are placed in 125 mL PTFE liners (up to four per liner) and about 2 mL HF and 0.2 mL HNO3 of the same strength as acid within beakers containing samples are added to the liners. The liners are then slid into stainless steel Parr™ high pressure dissolution devices, which are sealed and brought up to a maximum of 200˚C for 8-16 hours (typically 175˚C for 12 hours).   Beakers are removed from liners and zircon is separated from leachate. Zircons are rinsed with >18 MΩ.cm water and sub boiled acetone. Then 2 mL of subboiled 6N HCl is added and beakers are set on a hotplate at 80˚-130˚C for 30 minutes and again rinsed with water and acetone.  Masses are estimated from the dimensions (volumes) of grains.  Single grains are transferred into clean 300 mL PFA mi-crocapsules (crucibles), and 50 mL 50% HF and 5 mL 14 N HNO3 are added. Each is spiked with a 233-235U-205Pb tracer solution (UBC or EARTHTIME ET535), capped and again placed in a Parr liner (8-15 microcapsules per liner).  HF and nitric acids in a 10:1 ratio, respectively, are added to the liner, which is then placed in Parr high pressure device and dissolution is achieved at 240˚C for 40 hours.  The resulting solutions are dried on a hotplate at 130˚C, 50 mL 6N HCl is added to microcapsules and fluorides are dissolved in high pressure Parr devices for 12 hours at 210˚C.  HCl solutions are transferred into clean 7 mL PFA beakers and dried with 2 mL of 0.5 N H3PO4.   Samples are loaded onto degassed, zone-refined Re filaments in 2 mL of silicic acid emitter (Gerstenberger and Haase, 1997).   168 Isotopic ratios are measured a modifed single collector VG-54R or 354S (with Sector 54 elec-tronics) thermal ionization mass spectrometer equiped with analogue Daly photomultipliers.  Analytical blanks are 0.2 pg for U and up to 1 pg for Pb. U fractionation was determined directly on individual runs using the EARTHTIME ET535 mixed 233-235U-205Pb isotopic tracer and Pb iso-topic ratios were corrected for fractionation of 0.25%/amu, based on replicate analyses of NBS-982 reference material and the values recommended by Thirlwall (2000).  Data reduction em-ployed the excel-based program of Schmitz and Schoene (2007). Standard concordia diagrams were constructed and regression intercepts, weighted averages calculated with Isoplot (Ludwig, 2003). Unless otherwise noted all errors are quoted at the 2 sigma or 95% level of confidence. Isotopic dates are calculated with the deay constants l238=1.55125E-10 and l235=9.8485E-10 (Jaffe et al, 1971). EARTHTIME U-Pb synthetic solutions  are analysed on an on-going basis to moni-tor the accuracy of results.  Sample ID Analyte HOLE-ID DEPTHUTM W84E 19SUTM W84N 19SALT DEMAG0012 Drill Core LHDH21 554AG0013 Drill Core LHDH21 725AG0026 Outcrop 443208 6865700 3564AG127 Outcrop 442822 6864601 4677AG129 Outcrop 442702 6864538 4676 Table C1: Location for U/Pb geochronology  samples.169Table C2: U/PB geochronology data.170Table C2 cont.  : U/PB geochronology data171Figure C2: zircon detail of sample AG0013.Figure C1:Concordia diagram. Sample AG0013.Sample ID: AG0013172Figure C5: Zircons detail of sample AG127.Figure C4: AG127 concordia diagram, youngest de-tails.Figure C3: AG127 concordia diagram. Sample AG127.Sample ID: AG127173Figure C8: Zircons of AG0012 sample.Figure C7: Concordia diagram (youngest details). Sample AG0012. Figure C6: Concordia diagram. Sample AG0012.Sample ID: AG0012174Figure C12: Weighted mean 206Pb/238U CA-TIMS dates of sample AG129.Figure C11: Zircon of sample AG129.Figure C10: Youngest data of Concordia diagram. Sample AG129.   Figure C9: Concordia diagram. Sample AG129.Sample ID: AG0129175Figure C14: Weighted mean 206Pb/238U CA-TIMS dates of sample AG0026.Figure C13: Concordia diagram. Sample AG0026.Sample ID: AG0026176Appendix D:   Short-Wave Infrared spectroscopy (SWIR)177SWIR data of selected samples of Los HeladosThis appendix consists of short-wave infrared methodology (SWIR) data of selected samples from the Los Helados Cu/Au porphyry, using a portable reflectance spectrometer ASD Terraspec ®. Analytical spectra interpretation was done used The Spectral Geologist software (TSA_S). Wavelength 2200nm (w2200) is the absorption feature for muscovite and wavelength 2350nm (w2350) is the absorption feature for chlorite. Maximum depth of the absorption features in the wavelength 1900nm and 2200nm are (hqd1900) and (hqd2200), respectively. Sericite crystallinity was calculated as the AlOH peak depth at ~2,200 nm divided by the H2O peak depth at ~1,900 nm on a hull quotient SWIR spectrum. 178Hole-Id Depth UTM W84EUTM W84NALT  Mineral 1  Mineral 2  w 2200  hdq 2200w 2350 hdq 2350hdq 1900LHDH02 98 Muscovite 2205.94 0.256 2344.16 0.12 0.27LHDH02 118 Paragonite 2194.09 0.389 2346.13 0.24 0.36LHDH02 130 Illite 2201.35 0.206 2343.49 0.13 0.20LHDH02 140 Muscovite 2199.19 0.359 2358.6 0.26 0.42LHDH02 150 Muscovite 2196.87 0.303 2339.63 0.16 0.30LHDH02 160 Muscovite 2201.72 0.34 2344.56 0.20 0.30LHDH02 172 Muscovite 2202.17 0.212 2351.35 0.14 0.22LHDH02 178 Paragonite 2195.38 0.327 2341.65 0.12 0.47LHDH02 180 Muscovite 2195.79 0.469 NULL 0.36 0.40LHDH02 194 Muscovite 2199.06 0.375 2347.37 0.28 0.26LHDH02 204 Muscovite 2196.58 0.39 2332.61 0.30 0.35LHDH02 212 Illite 2203.61 0.478 2352.34 0.27 0.60LHDH02 224 Muscovite 2201.06 0.364 2345.34 0.23 0.34LHDH02 234 Illite 2198.26 0.641 NULL 0.35 0.84LHDH02 244 Illite 2199.82 0.415 2338.92 0.24 0.40LHDH02 262 Muscovite 2204.01 0.297 2334.15 0.18 0.30LHDH02 274 Illite 2198.07 0.431 2348.39 0.26 0.28LHDH02 284 Muscovite 2194.59 0.389 2348.65 0.29 0.64LHDH02 292 Muscovite 2203.45 0.349 2343.04 0.24 0.53LHDH02 302 Muscovite 2205.32 0.284 2339.45 0.18 0.31LHDH02 322 Illite 2209.27 0.187 2345.99 0.14 0.23LHDH02 352 Muscovite 2208.93 0.15 2351.98 0.12 0.22LHDH02 362 Muscovite 2206.35 0.272 2340.67 0.18 0.21 Table D1: Location and SWIR results.179LHDH02 372 Muscovite 2203.23 0.317 2350.91 0.22 0.24LHDH02 382 Muscovite 2197.10 0.257 2352.75 0.15 0.15LHDH02 392 Muscovite 2209.11 0.177 2351.34 0.15 0.15LHDH02 402 Muscovite 2205.07 0.172 2337.03 0.11 0.25LHDH02 414 Muscovite 2210.57 0.162 2342.42 0.12 0.18LHDH02 436 Muscovite 2205.51 0.285 2338.04 0.24 0.26LHDH02 458 Muscovite 2205.72 0.264 2340.36 NULL 0.27LHDH02 468 Illite 2195.56 0.218 2350.31 0.15 0.19LHDH02 490 Illite 2207.86 0.144 NULL 0.14 0.14LHDH10 26 Illite 2207.21 0.273 2336.75 0.16 0.32LHDH10 34 Muscovite 2200.18 0.157 2339.08 0.09 0.32LHDH10 66 Muscovite 2205.38 0.321 2338.7 0.17 0.45LHDH10 68 Illite 2204.14 0.244 2355.24 0.12 0.33LHDH10 84 Muscovite 2207.53 0.263 2343.59 0.17 0.31LHDH10 104 Muscovite 2210.48 0.194 2350.5 0.11 0.33LHDH10 114 Muscovite 2203.62 0.289 2338.74 0.14 0.28LHDH10 302 Muscovite 2203.63 0.245 2342.58 0.15 0.28LHDH10 314 Muscovite 2202.87 0.221 NULL 0.12 0.18LHDH10 322 Muscovite 2198.42 0.158 2340.61 0.08 0.15LHDH10 338 Muscovite 2195.57 0.274 2339.27 0.17 0.22LHDH10 348 Paragonite 2204.41 0.169 2354.23 0.13 0.26LHDH17 157 Muscovite NULL 2199.86 0.384 2348.63 0.21 0.10LHDH17 358 Muscovite NULL 2202.92 0.418 2349.16 0.22 0.18LHDH17 439 Muscovite Kaolinite 2208.9 0.286 2350.16 0.13 0.18LHDH17 491 Muscovite Gypsum 2210.54 0.184 2351.58 0.13 0.18LHDH17 491 Muscovite NULL 2209.19 0.188 2348.91 0.13 0.12LHDH17 524 Muscovite NULL 2206.22 0.105 2336.54 0.08 0.11180LHDH17 589 Muscovite NULL 2204.66 0.2 2350.08 0.11 0.03LHDH17 659 Muscovite Gypsum 2208.91 0.14 2343.31 0.03 0.24LHDH17 659 Muscovite Gypsum 2208.87 0.187 2347.21 0.07 0.25LHDH17 705 Muscovite NULL 2204.99 0.18 2349.84 0.11 0.06LHDH17 755 Biotite Muscovite 2208.79 0.118 2343.76 0.15 0.13LHDH17 766 Muscovite Gypsum 2209.25 0.139 2343.73 0.04 0.28LHDH17 795 Muscovite Gypsum 2208.71 0.083 2349.61 0.03 0.22LHDH17 795 Muscovite Gypsum 2209.22 0.145 2348.47 0.05 0.27LHDH17 795 Muscovite Gypsum 2209.13 0.118 2342.96 0.04 0.26LHDH17 826 Gypsum Muscovite 2209.89 0.068 2339.5 0.01 0.27LHDH17 826 Muscovite Gypsum 2209.23 0.12 2341.25 0.02 0.27LHDH17 835 Muscovite Kaolinite 2208.59 0.218 2348.62 0.08 0.21LHDH17 835 Muscovite Kaolinite 2208.63 0.185 2350.4 0.06 0.16LHDH17 889 Muscovite Gypsum 2208.6 0.185 2348.09 0.03 0.28LHDH17 889 Muscovite Gypsum 2208.71 0.185 2347.15 0.03 0.28LHDH17 947 Phlogopite Gypsum NULL NULL 2331.36 0.07 0.15LHDH17 990 Gypsum Phengite 2213.42 0.044 2332.33 0.03 0.28LHDH17 1007 Gypsum NULL NULL NULL 2329.28 0.04 0.35LHDH17 1009 Phlogopite Muscovite 2211.28 0.032 2334.65 0.10 0.07LHDH17 1073 Illite NULL 2208.59 0.157 2339.7 0.06 0.33LHDH17 1073 Muscovite NULL 2207.85 0.109 2339.95 0.04 0.28LHDH17 1119 Phlogopite NULL NULL NULL 2333.84 0.08 0.10LHDH17 1182 IntChlorite Illite 2208.04 0.1 2334.27 0.09 0.16LHDH17 1185 Muscovite NULL 2208.34 0.133 2336.57 0.19 0.13LHDH19 20 Muscovite NULL 2202.04 0.31 2347.83 0.14 0.19LHDH19 30 Illite Gypsum 2195.82 0.359 2345.16 0.14 0.28LHDH19 40 Muscovite Gypsum 2202.71 0.391 2346.69 0.17 0.40181LHDH19 50 Muscovite Gypsum 2200.05 0.265 2347.06 0.11 0.24LHDH19 60 Muscovite Gypsum 2204.93 0.309 2346.78 0.13 0.35LHDH19 70 Muscovite Gypsum 2208.44 0.064 2347.39 0.02 0.12LHDH19 80 Muscovite NULL 2208.92 0.176 2349.69 0.08 0.13LHDH19 90 Muscovite Gypsum 2199.22 0.316 2345.98 0.12 0.28LHDH19 90 Muscovite Gypsum 2199.19 0.316 2344.56 0.11 0.28LHDH19 100 Muscovite Gypsum 2200.12 0.305 2347.83 0.12 0.26LHDH19 100 Muscovite Gypsum 2200.5 0.304 2347.32 0.13 0.26LHDH19 100 Paragonite Gypsum 2195.07 0.24 2341.52 0.06 0.18LHDH19 100 Paragonite Gypsum 2195.03 0.241 2345.64 0.07 0.18LHDH19 130 Muscovite Gypsum 2198.78 0.33 2347.09 0.14 0.30LHDH19 140 Muscovite Gypsum 2201.07 0.271 2347.71 0.11 0.24LHDH19 150 Muscovite Gypsum 2203.89 0.269 2349.64 0.14 0.28LHDH19 150 Muscovite Gypsum 2204.2 0.271 2348.82 0.13 0.28LHDH19 160 Illite Gypsum 2198.7 0.255 2346.44 0.06 0.35LHDH19 170 Muscovite Gypsum 2201.32 0.233 2347.58 0.08 0.20LHDH19 180 Muscovite Gypsum 2205.59 0.252 2348.54 0.09 0.30LHDH19 190 Muscovite Gypsum 2200.05 0.449 2346.41 0.17 0.54LHDH19 200 Muscovite Gypsum 2201.13 0.352 2344.84 0.15 0.34LHDH19 210 Muscovite NULL 2200.82 0.321 2345.88 0.15 0.21LHDH19 220 Muscovite Gypsum 2202.54 0.255 2347.12 0.11 0.27LHDH19 230 Muscovite Gypsum 2200.46 0.283 2346.12 0.07 0.42LHDH19 240 Muscovite Gypsum 2199.58 0.193 2345.64 0.08 0.15LHDH19 250 Illite Gypsum 2198.49 0.299 2341.65 0.13 0.23LHDH19 260 Muscovite NULL 2200.26 0.267 2349.54 0.13 0.14LHDH19 270 Muscovite NULL 2202.91 0.118 2343.16 0.08 0.09LHDH19 280 Muscovite Gypsum 2202.65 0.086 2352.38 0.04 0.08182LHDH19 290 Muscovite Gypsum 2204.53 0.143 2349.88 0.06 0.22LHDH19 300 Muscovite NULL 2202.74 0.271 2345.56 0.13 0.06LHDH19 310 Muscovite NULL 2202.33 0.196 2348.39 0.09 0.10LHDH19 320 Muscovite Gypsum 2203.92 0.162 2347.99 0.06 0.12LHDH19 320 Muscovite Gypsum 2202.61 0.302 2345.45 0.09 0.33LHDH19 330 Muscovite Gypsum 2203.56 0.155 2350.25 0.06 0.14LHDH19 340 Muscovite NULL 2203.16 0.243 2350.68 0.11 0.17LHDH19 350 Muscovite NULL 2208.36 0.168 2350.98 0.09 0.06LHDH19 360 Muscovite NULL 2203.54 0.157 2346.86 0.06 0.21LHDH19 370 Muscovite Gypsum 2209.95 0.247 2351.58 0.13 0.32LHDH19 370 Muscovite Gypsum 2210.1 0.144 2349.87 0.05 0.19LHDH19 380 Muscovite Gypsum 2209.72 0.169 2348.77 0.08 0.15LHDH19 390 Muscovite NULL 2203.59 0.194 2348.5 0.10 0.13LHDH19 400 Muscovite Gypsum 2210.25 0.356 2346.82 0.18 0.42LHDH19 410 Muscovite Gypsum 2213.59 0.069 2353.59 0.02 0.15LHDH19 410 Gypsum Muscovite 2214 0.101 2339.46 0.01 0.33LHDH19 420 Muscovite Gypsum 2211.65 0.084 2343.78 0.02 0.17LHDH19 420 Muscovite Gypsum 2211.93 0.090 2351.66 0.02 0.24LHDH19 430 Muscovite Gypsum 2206.31 0.267 2349.43 0.14 0.22LHDH19 440 Gypsum Muscovite 2210.49 0.216 2348.51 0.05 0.58LHDH19 450 IntChlorite Gypsum NULL NULL 2341.37 0.13 0.27LHDH19 450 Muscovite NULL 2209.73 0.178 2350.41 0.07 0.16LHDH19 460 Muscovite NULL 2208.89 0.085 2346.58 0.04 0.05LHDH19 460 Muscovite Gypsum 2208.64 0.090 2349.64 0.03 0.15LHDH19 480 Muscovite Gypsum 2210.52 0.096 2342.35 0.03 0.23LHDH19 490 Muscovite Gypsum 2210.98 0.128 2351.78 0.04 0.25183LHDH19 500 Muscovite Montmo-rillonite2209.2 0.147 2350.48 0.05 0.14LHDH19 510 Muscovite Gypsum 2211.25 0.103 2352.25 0.05 0.16LHDH19 520 Muscovite Gypsum 2210.18 0.124 2349.46 0.06 0.16LHDH19 530 Muscovite Gypsum 2210.57 0.183 2351.26 0.03 0.42LHDH19 540 Illite NULL 2200.85 0.251 2348.88 0.12 0.06LHDH19 540 Muscovite Gypsum 2208.52 0.089 2351.14 0.03 0.11LHDH19 550 Muscovite Gypsum 2209.54 0.089 2352.54 0.03 0.11LHDH19 560 Muscovite Gypsum 2210.1 0.181 2344.65 0.07 0.26LHDH19 570 Muscovite Gypsum 2211.79 0.091 2350.76 0.05 0.16LHDH19 580 Muscovite Gypsum 2209.46 0.046 2352 0.01 0.12LHDH19 590 Muscovite Gypsum 2209.6 0.090 2350.59 0.02 0.25LHDH19 600 Muscovite Gypsum 2210.28 0.081 2350.76 0.03 0.19LHDH19 610 Muscovite Gypsum 2209.58 0.203 2349.69 0.01 0.47LHDH19 610 Muscovite Gypsum 2209.38 0.189 2349.5 0.02 0.42LHDH19 620 Muscovite NULL 2200.82 0.228 2346.35 0.11 0.12LHDH19 630 Muscovite Gypsum 2208.85 0.187 2348.97 0.05 0.32LHDH19 640 Muscovite Gypsum 2208.67 0.181 2352.37 0.05 0.27LHDH19 650 Muscovite Gypsum 2206.01 0.2 2347.08 0.08 0.28LHDH19 650 Muscovite NULL 2205.36 0.274 2349.01 0.13 0.21LHDH19 660 Muscovite NULL 2208.31 0.14 2345.83 0.07 0.11LHDH19 670 Muscovite Gypsum 2209.61 0.081 2353.93 0.01 0.22LHDH19 670 Muscovite Gypsum 2209.15 0.081 2341.76 0.01 0.22LHDH19 680 Muscovite Gypsum 2205.88 0.078 2344.51 0.03 0.09LHDH19 680 Muscovite NULL 2207.31 0.117 2350.7 0.07 0.08LHDH19 680 Muscovite NULL 2206.34 0.118 2349.66 0.06 0.08LHDH19 690 Muscovite Gypsum 2205.72 0.096 2352.02 0.03 0.17184LHDH19 700 Muscovite Gypsum 2207.66 0.301 2349.61 0.14 0.25LHDH19 700 Muscovite MgChlorite 2207.5 0.118 2350.69 0.07 0.05LHDH19 700 Muscovite MgChlorite 2207.88 0.126 2350.29 0.07 0.06LHDH19 720 Muscovite Kaolinite 2208.29 0.243 2349.7 0.11 0.14LHDH19 730 Muscovite NULL 2207.83 0.299 2350.04 0.17 0.18LHDH19 740 Muscovite NULL 2205.4 0.122 2350.15 0.08 0.03LHDH19 750 Muscovite NULL 2209.39 0.097 2351.73 0.05 0.06LHDH20 30 Muscovite Gypsum 2209 0.202 2348.51 0.08 0.24LHDH20 40 Muscovite NULL 2205.99 0.19 2346.33 0.08 0.20LHDH20 50 Muscovite NULL 2200.28 0.338 2344 0.14 0.26LHDH20 60 Muscovite Gypsum 2201.56 0.274 2349.14 0.12 0.26LHDH20 70 Muscovite NULL 2200.81 0.396 2345.87 0.20 0.25LHDH20 80 Muscovite NULL 2206.02 0.325 2347.48 0.16 0.21LHDH20 90 Muscovite Gypsum 2206.1 0.143 2346.44 0.06 0.19LHDH20 100 Muscovite Gypsum 2204.54 0.223 2347.88 0.11 0.25LHDH20 110 Muscovite Gypsum 2207.46 0.162 2346.16 0.06 0.23LHDH20 120 Muscovite Gypsum 2204.32 0.108 2346.51 0.03 0.34LHDH20 130 Muscovite NULL 2202.82 0.313 2347.79 0.16 0.12LHDH20 140 Muscovite Gypsum 2205.02 0.118 2350.84 0.03 0.37LHDH20 150 Muscovite Gypsum 2204.4 0.112 2347.67 0.02 0.47LHDH20 160 MgChlorite Gypsum NULL NULL 2333.75 0.04 0.11LHDH20 170 Muscovite NULL 2202.5 0.158 2347.89 0.07 0.12LHDH20 180 Muscovite NULL 2201.34 0.14 2349.77 0.05 0.56LHDH20 190 Muscovite NULL 2200.67 0.187 2343.8 0.08 0.44LHDH20 200 Muscovite NULL 2201.83 0.25 2345.88 0.13 0.13LHDH20 210 Muscovite Gypsum 2202.27 0.119 2346.13 0.05 0.29LHDH20 220 Muscovite NULL 2201.05 0.151 2344.04 0.06 0.05185LHDH20 230 Muscovite NULL 2201.58 0.161 2346.46 0.06 0.38LHDH20 240 Illite Gypsum 2198.89 0.136 2347.29 0.04 0.44LHDH20 250 Muscovite Gypsum 2202.32 0.124 2348.39 0.05 0.35LHDH20 260 Muscovite Gypsum 2200.74 0.186 2345.34 0.07 0.21LHDH20 270 Palygorskite Gypsum NULL NULL 2347.95 0.01 0.42LHDH20 280 Muscovite NULL 2199.92 0.359 2346.61 0.16 0.13LHDH20 290 Illite NULL 2198.91 0.289 2346.64 0.13 0.15LHDH20 300 Illite NULL 2199.1 0.281 2347.97 0.14 0.10LHDH20 310 Illite Gypsum 2202.21 0.338 2350.95 0.16 0.42LHDH20 320 Illite Gypsum 2201.57 0.305 2346.58 0.14 0.36LHDH20 330 Illite Gypsum 2200.95 0.196 2346.94 0.04 0.44LHDH20 340 Muscovite NULL 2202.58 0.189 2348.08 0.06 0.42LHDH20 350 Illite Gypsum 2199.43 0.277 2346.37 0.10 0.28LHDH20 360 Muscovite NULL 2202.37 0.167 2346.43 0.07 0.22LHDH20 370 Muscovite NULL 2202.83 0.253 2347.37 0.12 0.14LHDH20 380 Muscovite NULL 2202.59 0.318 2348.19 0.15 0.22LHDH20 390 Muscovite NULL 2203.18 0.313 2346.28 0.14 0.27LHDH20 400 Muscovite Gypsum 2204.3 0.166 2348.23 0.05 0.17LHDH20 410 Muscovite Gypsum 2202.48 0.225 2349.42 0.09 0.24LHDH20 420 Muscovite NULL 2202.64 0.079 2350.4 0.03 0.26LHDH20 430 Muscovite NULL 2205.39 0.241 2350.1 0.13 0.13LHDH20 440 Muscovite Gypsum 2204.08 0.211 2347.43 0.11 0.33LHDH20 460 Muscovite Gypsum 2203.69 0.18 2352 0.07 0.23LHDH20 470 Muscovite NULL 2204.05 0.146 2354.86 0.07 0.09LHDH20 470 Muscovite NULL 2204.83 0.144 2351.48 0.07 0.09LHDH20 480 Muscovite NULL 2202.93 0.089 2348.86 0.03 0.13LHDH20 490 Muscovite NULL 2204.03 0.101 2352.56 0.04 0.03186LHDH20 500 Muscovite NULL 2203.79 0.202 2350.42 0.10 0.10LHDH20 510 Muscovite NULL 2203.49 0.251 2346.73 0.12 0.17LHDH20 520 Muscovite Gypsum 2203.35 0.111 2350.09 0.05 0.11LHDH20 540 Muscovite Gypsum 2209.25 0.118 2344.27 0.06 0.12LHDH20 550 Muscovite NULL 2205.4 0.133 2344.85 0.05 0.10LHDH20 560 Muscovite NULL 2204.25 0.119 2341.65 0.07 0.08LHDH20 570 Muscovite Gypsum 2207.87 0.083 2347.36 0.04 0.09LHDH20 580 Muscovite NULL 2204.31 0.115 2350.47 0.08 0.08LHDH20 590 Gypsum K_Alunite NULL NULL 2321.64 0.04 0.41LHDH20 600 Muscovite NULL 2207.52 0.084 2353.51 0.04 0.03LHDH20 600 Palygorskite NULL NULL NULL 2342.46 0.01 0.29LHDH20 610 Muscovite NULL 2207 0.132 2349.44 0.10 0.06LHDH20 610 Muscovite NULL 2207.75 0.112 2344.37 0.05 0.08LHDH20 620 Muscovite NULL 2209.66 0.121 2350.99 0.06 0.07LHDH20 640 Muscovite Gypsum 2207.41 0.142 2347.02 0.02 0.24LHDH20 650 Muscovite NULL 2207.35 0.088 2342.82 0.04 0.03LHDH20 660 Muscovite Siderite 2205.64 0.124 2345.61 0.06 0.22LHDH20 670 Muscovite NULL 2208.64 0.122 2347.97 0.08 0.05LHDH20 680 Muscovite NULL 2209.2 0.103 2343.65 0.05 0.06LHDH20 690 Muscovite NULL 2208.04 0.088 2344.12 0.03 0.07LHDH20 700 Muscovite NULL 2209.26 0.076 2337.8 0.09 0.04LHDH20 720 Illite Kaolinite 2208.76 0.077 2324.25 NULL 0.11LHDH20 730 Muscovite NULL 2205.06 0.212 2350.29 0.10 0.12LHDH20 740 Muscovite MgChlorite 2205.38 0.218 2345.35 0.15 0.03LHDH20 750 Muscovite NULL 2207.87 0.154 2343.35 0.11 0.09LHDH21 25 Muscovite NULL 2199.22 0.326 2346.76 0.11 0.19LHDH21 110 Muscovite Kaolinite 2208.75 0.173 2341.98 0.07 0.23187LHDH21 110 Illite NULL 2200.58 0.371 2348.95 0.24 0.09LHDH21 110 Muscovite NULL 2200.51 0.309 2349.53 0.18 0.09LHDH21 116 Muscovite Gypsum 2202.63 0.147 2346.35 0.06 0.16LHDH21 132 Muscovite NULL 2207.47 0.052 2342.44 0.05 0.08LHDH21 132 Muscovite NULL 2207.79 0.041 2343.92 0.04 0.08LHDH21 133 Muscovite Gypsum 2208.41 0.178 2346.77 0.05 0.23LHDH21 133 Muscovite Gypsum 2208.66 0.139 2349.63 0.01 0.29LHDH21 143 Halloysite Gypsum NULL NULL 2345.05 0.03 0.16LHDH21 143 Muscovite Kaolinite 2208.57 0.146 2329.53 0.05 0.14LHDH21 215 Muscovite Gypsum 2207.48 0.277 2348.93 0.10 0.38LHDH21 215 Muscovite Gypsum 2205.21 0.244 2349.52 0.10 0.24LHDH21 226 Muscovite Gypsum 2210.87 0.18 2348.35 0.06 0.24LHDH21 226 Muscovite Gypsum 2209.09 0.123 2347.07 0.06 0.12LHDH21 226 Muscovite Gypsum 2209.16 0.228 2349.24 0.12 0.20LHDH21 260 Muscovite Gypsum 2209.81 0.202 2350.29 0.08 0.23LHDH21 306 Muscovite Gypsum 2203.79 0.203 2350.18 0.10 0.23LHDH21 306 Muscovite Gypsum 2205.4 0.205 2350.18 0.09 0.23LHDH21 342 Muscovite NULL 2206.21 0.2 2348.33 0.11 0.11LHDH21 357 Muscovite Gypsum 2208.97 0.225 NULL NULL 0.29LHDH21 357 Muscovite NULL 2207.53 0.182 2353.47 0.09 0.15LHDH21 389 Muscovite Gypsum 2209.95 0.189 2346.84 0.09 0.24LHDH21 389 Muscovite Gypsum 2203.05 0.219 2346.75 0.09 0.32LHDH21 554 Muscovite NULL 2209.92 0.27 2350.81 0.14 0.26LHDH21 587 Muscovite Gypsum 2207.9 0.19 2343.69 0.09 0.31LHDH21 587 Muscovite Gypsum 2207.37 0.195 2344.26 0.08 0.38LHDH21 587 Muscovite Gypsum 2207.15 0.25 2347.07 0.10 0.37LHDH21 602 Gypsum Muscovite 2209.67 0.144 2357.78 NULL 0.46188LHDH21 602 Muscovite Gypsum 2208.21 0.295 2346.19 0.10 0.39LHDH21 725 Muscovite Gypsum 2210.03 0.218 2342.07 0.05 0.50LHDH21 934 Muscovite NULL 2208.9 0.165 2348.03 0.07 0.15LHDH21 934 Muscovite Gypsum 2208.97 0.163 2342.13 0.03 0.38LHDH21 954 Muscovite Gypsum 2209.13 0.231 2344.38 0.05 0.43LHDH21 954 Muscovite Gypsum 2209.18 0.23 2343.55 0.05 0.43LHDH21 957 Muscovite Kaolinite 2208.8 0.149 2342.36 0.05 0.19LHDH21 957 Muscovite Kaolinite 2208.82 0.133 2345.74 0.05 0.17LHDH21 1016 Muscovite Gypsum 2206.56 0.156 2336.32 0.10 0.29LHDH21 1141 Phlogopite NULL NULL NULL 2326.86 0.12 0.10LHDH21 1173 Kaolinite Phlogo-pite1NULL NULL 2327.73 0.08 0.14LHDH21 1230 Biotite Horn-blendeNULL NULL 2336.16 0.20 0.19LHDH21 1330 Phlogopite Gypsum NULL NULL 2326.61 0.06 0.06LHDH21 1393 Phlogopite Kaolinite NULL NULL 2329.46 0.13 0.11LHDH21 1399 Phlogopite Kaolinite NULL NULL 2327.16 0.15 0.13LHDH21 Muscovite Gypsum 2211.48 0.185 2346 0.09 0.20LHDH23 40 Muscovite Jarosite 2201.13 0.31 2347.18 0.09 0.12LHDH23 50 Illite Paragonite 2195.79 0.37 2342.98 0.14 0.18LHDH23 60 Illite K_Alunite 2192.3 0.324 2321.77 0.13 0.08LHDH23 60 Illite K_Alunite 2192.36 0.331 2321.92 0.13 0.08LHDH23 70 Illite NULL 2198.37 0.329 2345.44 0.13 0.10LHDH23 80 Muscovite NULL 2199.32 0.46 2347.44 0.21 0.13LHDH23 80 Muscovite NULL 2199.1 0.422 2346.71 0.19 0.10LHDH23 90 Illite Paragonite 2196.43 0.294 2345.19 0.13 0.11LHDH23 100 Paragonite Gypsum 2194.52 0.189 2338.32 0.05 0.28LHDH23 110 Muscovite NULL 2197.6 0.211 2348.12 0.08 0.11189LHDH23 120 Paragonite NULL 2195.8 0.28 2349.78 0.11 0.26LHDH23 130 Muscovite Gypsum 2198.12 0.174 2345.6 0.05 0.15LHDH23 140 Illite Gypsum 2198.02 0.303 2347.33 0.13 0.27LHDH23 150 Paragonite Gypsum 2194.25 0.359 2343.34 0.11 0.45LHDH23 150 Illite Gypsum 2195.99 0.255 2343.32 0.06 0.36LHDH23 160 Muscovite Gypsum 2199.08 0.309 2346.19 0.10 0.40LHDH23 170 Illite Gypsum 2197.93 0.307 2343.92 0.13 0.26LHDH23 180 Muscovite NULL 2201.89 0.261 2349.44 0.13 0.10LHDH23 190 Illite Paragonite 2196.93 0.346 2343.49 0.15 0.13LHDH23 200 Muscovite NULL 2202.24 0.085 2350 0.04 0.09LHDH23 210 Muscovite Gypsum 2201.6 0.212 2342.52 0.02 0.50LHDH23 220 Muscovite Gypsum 2203.34 0.209 2347.43 0.05 0.38LHDH23 230 Muscovite Gypsum 2205.28 0.040 2335.47 0.01 0.17LHDH23 230 Muscovite Gypsum 2206.39 0.071 2340.7 0.02 0.15LHDH23 240 Muscovite NULL 2205.03 0.187 2345.27 0.08 0.17LHDH23 240 Muscovite Gypsum 2207.58 0.205 2348.36 0.03 0.41LHDH23 250 Muscovite Gypsum 2204.35 0.169 2342.43 0.05 0.22LHDH23 260 Muscovite Gypsum 2201.56 0.495 2347.15 0.25 0.50LHDH23 270 Muscovite Gypsum 2202.23 0.219 2347.69 0.09 0.21LHDH23 280 Muscovite NULL 2203.21 0.233 2347.36 0.10 0.16LHDH23 280 Muscovite NULL 2202.1 0.397 2347.31 0.18 0.29LHDH23 290 Muscovite Gypsum 2203.35 0.119 2351.33 0.05 0.11LHDH23 300 Muscovite NULL 2203.82 0.261 2349.48 0.14 0.12LHDH23 310 Muscovite Gypsum 2205.48 0.123 2338.46 0.04 0.16LHDH23 320 Muscovite Gypsum 2205.42 0.232 2350.19 0.10 0.22LHDH23 330 Muscovite NULL 2206.51 0.205 2350.06 0.11 0.07LHDH23 330 Muscovite NULL 2207.36 0.192 2346.86 0.10 0.11190LHDH23 340 Muscovite Gypsum 2207.79 0.156 2346.79 0.06 0.16LHDH23 340 Muscovite Gypsum 2206.49 0.163 2344.2 0.04 0.25LHDH23 360 Muscovite Gypsum 2205.32 0.205 2346.85 0.05 0.39LHDH23 360 Gypsum NULL NULL NULL 2354.37 NULL 0.52LHDH23 370 Muscovite Gypsum 2208.02 0.146 2350.24 0.05 0.20LHDH23 380 Muscovite NULL 2207.08 0.145 2349.85 0.09 0.04LHDH23 380 Muscovite NULL 2207.69 0.155 2350.05 0.10 0.03LHDH23 390 Muscovite NULL 2205.63 0.139 2349.54 0.07 0.03LHDH23 390 Muscovite NULL 2208.25 0.154 2351.01 0.08 0.05LHDH23 400 Muscovite Gypsum 2210.96 0.17 2348.18 0.04 0.33LHDH23 400 Muscovite NULL 2209.6 0.155 2350.46 0.09 0.03LHDH23 410 Muscovite Gypsum 2213.02 0.23 2347.69 0.09 0.22LHDH23 410 Muscovite Gypsum 2208.01 0.28 2350.86 0.14 0.21LHDH23 420 Muscovite Gypsum 2209.65 0.149 2348.42 0.07 0.15LHDH23 430 Muscovite NULL 2204.49 0.223 2348.36 0.11 0.10LHDH23 440 Kaolinite Gypsum NULL NULL 2327.28 0.01 0.17LHDH23 440 Kaolinite Muscovite 2208.76 0.132 2353.5 0.02 0.13LHDH23 460 Muscovite NULL 2208.78 0.238 2349.02 0.13 0.05LHDH23 460 Muscovite NULL 2208.97 0.238 2349.98 0.13 0.05LHDH23 460 Muscovite NULL 2208.68 0.242 2350.33 0.13 0.07LHDH23 470 Muscovite Gypsum 2208.17 0.123 2348.54 0.05 0.12LHDH23 470 Muscovite NULL 2208.83 0.138 2342.85 0.09 0.05LHDH24 30 Illite NULL 2197.22 0.16 2342.93 0.05 0.06LHDH24 40 Muscovite Gypsum 2202.69 0.168 2342.09 0.05 0.24LHDH24 50 Gypsum NULL NULL NULL 2352.45 0.04 0.63LHDH24 50 Muscovite Gypsum 2216.89 0.041 2352.96 0.02 0.13LHDH24 51 Muscovite NULL 2199.92 0.325 2346.35 0.15 0.23191LHDH24 80 Muscovite NULL 2200.77 0.303 2346.42 0.13 0.19LHDH24 90 Muscovite NULL 2199.88 0.272 2345.83 0.12 0.16LHDH24 100 Illite Gypsum 2198.79 0.359 2347.18 0.10 0.46LHDH24 100 Muscovite Gypsum 2199.51 0.221 2344.05 0.07 0.27LHDH24 110 Muscovite NULL 2199.24 0.368 2349.55 0.17 0.16LHDH24 110 Muscovite NULL 2200.52 0.388 2347.86 0.21 0.09LHDH24 120 Muscovite NULL 2201.79 0.269 2349.48 0.14 0.10LHDH24 120 Illite Gypsum 2196.93 0.269 2344.32 0.09 0.21LHDH24 130 Illite Gypsum 2197.06 0.269 2345.99 0.09 0.21LHDH24 140 Muscovite Gypsum 2199.58 0.223 2344.69 0.08 0.27LHDH24 140 Muscovite A 2200.38 0.324 2344.57 0.15 0.26LHDH24 150 Muscovite Gypsum 2200.22 0.325 2344.93 0.14 0.26LHDH24 150 Muscovite NULL 2199.93 0.493 2345.84 0.26 0.31LHDH24 160 Illite NULL 2197.15 0.32 2344.98 0.15 0.16LHDH24 160 Kaolinite Gypsum NULL NULL 2351.53 NULL 0.45LHDH24 170 Gypsum Illite 2197.31 0.199 2342.89 0.01 0.46LHDH24 170 Illite Gypsum 2198.78 0.196 2345.19 0.05 0.22LHDH24 180 Muscovite Gypsum 2198.87 0.116 2342.73 0.02 0.17LHDH24 180 Muscovite Gypsum 2200.09 0.126 2345.47 0.03 0.18LHDH24 190 Muscovite Gypsum 2198.57 0.247 2342.17 0.08 0.29LHDH24 200 Muscovite NULL 2199.9 0.093 2346.79 0.03 0.05LHDH24 210 Muscovite NULL 2201.96 0.158 2345.07 0.06 0.09LHDH24 220 Muscovite Gypsum 2201.48 0.119 2342.76 0.03 0.21LHDH24 230 Muscovite Gypsum 2203.51 0.215 2348.81 0.08 0.23LHDH24 230 Muscovite NULL 2201.62 0.354 2346.94 0.16 0.15LHDH24 240 Muscovite Gypsum 2203.53 0.106 2350.51 0.04 0.13LHDH24 240 Muscovite Gypsum 2209.56 0.193 2346.31 0.07 0.28192LHDH24 250 Muscovite Gypsum 2202.4 0.256 2348.9 0.12 0.25LHDH24 250 Muscovite Gypsum 2202.91 0.177 2344.14 0.07 0.16LHDH24 260 Muscovite Gypsum 2202.3 0.125 2350.21 0.05 0.11LHDH24 280 Muscovite Gypsum 2203.04 0.087 2350.76 0.01 0.28LHDH24 280 Muscovite Gypsum 2204.17 0.146 2345.02 0.03 0.30LHDH24 290 Muscovite Gypsum 2213.85 0.102 2338.82 0.03 0.30LHDH24 290 Muscovite Gypsum 2213.34 0.042 2342.75 0.01 0.16LHDH24 300 Muscovite Gypsum 2206.3 0.099 2345.15 0.02 0.16LHDH24 300 Muscovite Gypsum 2204.43 0.115 2343.26 0.03 0.17LHDH24 330 Muscovite Gypsum 2207.63 0.254 2348.11 0.13 0.24LHDH24 330 Muscovite Gypsum 2212.18 0.223 2349.94 0.04 0.48LHDH24 340 Muscovite Gypsum 2210.12 0.095 2347.29 0.03 0.10LHDH24 350 Muscovite NULL 2210.34 0.125 2353.14 0.06 0.07LHDH24 360 Muscovite NULL 2207.92 0.107 2349.93 0.04 0.11LHDH24 360 IntChlorite Gypsum NULL NULL 2340.05 0.08 0.37LHDH24 380 Muscovite NULL 2207.7 0.346 2349.66 0.19 0.25LHDH24 380 Muscovite NULL 2207.42 0.23 2347.45 0.11 0.18LHDH24 390 Muscovite Gypsum 2211.64 0.081 2351.02 0.02 0.22LHDH24 390 Muscovite Gypsum 2215.57 0.065 2338.87 0.05 0.19LHDH24 400 Muscovite NULL 2209.65 0.255 2347.51 0.14 0.19LHDH24 400 Muscovite Gypsum 2209.84 0.225 2345.15 0.11 0.27LHDH24 410 Muscovite NULL 2208.17 0.165 2348.08 0.09 0.07LHDH24 410 Muscovite NULL 2208.4 0.229 2348.38 0.14 0.12LHDH24 420 Muscovite Gypsum 2210.11 0.308 2348.13 0.15 0.31LHDH24 440 Muscovite NULL 2208.38 0.209 2350.25 0.12 0.08LHDH24 450 Muscovite NULL 2208.13 0.174 2348.81 0.09 0.09LHDH24 450 Muscovite Gypsum 2210.09 0.21 2344.94 0.04 0.42193LHDH24 460 Muscovite Gypsum 2210.22 0.12 2348.35 0.04 0.21LHDH24 470 Muscovite NULL 2207.98 0.129 2353.4 0.08 0.08LHDH24 470 Muscovite Gypsum 2211.43 0.139 2354.47 0.07 0.34LHDH24 480 Muscovite Gypsum 2209.2 0.064 2358.5 0.02 0.16LHDH24 480 Muscovite Gypsum 2211.58 0.060 2344.3 0.01 0.24LHDH24 490 Muscovite Gypsum 2210.72 0.129 2350.52 0.06 0.15LHDH24 490 Muscovite Gypsum 2209.73 0.15 2350.7 0.06 0.23LHDH24 500 Muscovite Gypsum 2209.43 0.083 2356.08 0.03 0.21LHDH24 510 Muscovite Gypsum 2210.36 0.091 2342.57 0.01 0.18LHDH24 520 Muscovite NULL 2208.91 0.146 2348.52 0.08 0.05LHDH24 530 Muscovite Gypsum 2207.44 0.030 2325.74 0.01 0.07LHDH24 530 Muscovite Gypsum 2213.75 0.082 2342.43 0.03 0.21LHDH24 540 Phengite Gypsum 2219.12 0.046 2350.83 0.03 0.13LHDH24 540 Muscovite NULL 2213.36 0.291 2347.74 0.16 0.24LHDH24 550 Muscovite Gypsum 2209.85 0.070 2348.48 0.01 0.21LHDH24 580 Muscovite Gypsum 2211.18 0.063 2356.43 NULL 0.16LHDH24 600 Muscovite NULL 2207.54 0.278 2348.39 0.15 0.13LHDH24 600 Muscovite Gypsum 2208.88 0.296 2350.67 0.14 0.32LHDH24 610 Muscovite Gypsum 2209.96 0.040 2356.98 0.03 0.22LHDH24 620 Gypsum NULL NULL NULL 2330.51 0.01 0.13LHDH24 630 Muscovite Gypsum 2205.87 0.151 2349.07 0.04 0.27LHDH24 640 Muscovite Gypsum 2207.83 0.050 2345.35 0.02 0.11LHDH24 650 Muscovite Gypsum 2211.61 0.071 2351.3 0.01 0.23LHDH24 660 Muscovite Gypsum 2208.8 0.089 2336.66 0.03 0.20LHDH24 670 Gypsum Muscovite 2210.34 0.060 2331.39 0.04 0.31LHDH24 680 Muscovite NULL 2209.92 0.155 2345.7 0.08 0.09LHDH24 680 Gypsum Muscovite 2210.41 0.094 2351.64 0.01 0.32194LHDH24 710 Muscovite NULL 2206.92 0.123 2349.57 0.08 0.08LHDH24 720 Muscovite Gypsum 2208.43 0.15 2347.39 0.06 0.35LHDH24 730 Muscovite NULL 2202.81 0.283 2347.48 0.14 0.07LHDH24 740 Gypsum Phengite 2215.42 0.054 2337.02 0.01 0.30LHDH24 750 IntChlorite FeTourma-lineNULL NULL 2336.83 0.18 0.13LHDH24 760 Muscovite NULL 2206.03 0.258 2349.22 0.16 0.10LHDH24 770 Muscovite Gypsum 2208.63 0.25 2348.33 0.10 0.27LHDH24 780 Muscovite Gypsum 2209.23 0.137 2351 0.03 0.27LHDH24 790 Muscovite NULL 2207.36 0.111 2347.11 0.06 0.10LHDH24 800 Muscovite Gypsum 2208.49 0.181 2345.8 0.08 0.18LHDH24 810 Muscovite Gypsum 2208.95 0.288 2349.73 0.14 0.30LHDH24 820 Muscovite NULL 2208.06 0.215 2351.04 0.12 0.07LHDH24 830 Muscovite Gypsum 2208.95 0.191 2344.36 0.12 0.20LHDH24 840 Muscovite NULL 2207.7 0.19 2352.28 0.11 0.13LHDH24 870 Muscovite Gypsum 2207.01 0.249 2349.76 0.09 0.33LHDH24 890 Muscovite Gypsum 2208.77 0.069 2353.52 0.01 0.21LHDH24 900 Muscovite Gypsum 2209.6 0.057 2349.58 0.01 0.19LHDH24 910 Muscovite NULL 2202.43 0.352 2349.37 0.19 0.11LHDH24 920 Muscovite NULL 2205 0.131 2340.76 0.10 0.11LHDH24 930 Muscovite NULL 2204.22 0.289 2348.17 0.17 0.06LHDH28 451 Muscovite Gypsum 2208.14 0.147 2346.02 0.05 0.27LHDH28 451 Muscovite Gypsum 2208.68 0.108 2352.38 0.03 0.23LHDH28 496 Muscovite NULL 2205 0.326 2348.61 0.20 0.19LHDH28 499 Gypsum Muscovite 2209.04 0.166 2352.89 0.01 0.39LHDH28 499 Muscovite Gypsum 2208 0.23 2348.19 0.09 0.39LHDH28 521 Muscovite NULL 2203.42 0.444 2348.63 0.25 0.14LHDH28 577 Muscovite Gypsum 2208.27 0.243 2344.97 0.09 0.34195LHDH28 577 Muscovite Gypsum 2208.3 0.226 2349 0.07 0.38LHDH28 679 Muscovite Gypsum 2205.57 0.248 2345.58 0.11 0.34LHDH28 779 Muscovite Gypsum 2206.14 0.286 2346.33 0.14 0.31LHDH28 947 Muscovite NULL 2203.19 0.546 2348.12 0.34 0.06LHDH39 190 Muscovite NULL 2207.4 0.147 2345.48 0.09 0.13LHDH39 190 Muscovite Gypsum 2209.89 0.186 2347.68 0.08 0.28LHDH39 256 Muscovite Gypsum 2208.47 0.135 2346.49 0.03 0.30LHDH39 370 Muscovite Gypsum 2209.29 0.34 2350.05 0.09 0.47LHDH39 370 Halloysite Gypsum NULL NULL 2350.51 0.05 0.35LHDH39 557 Muscovite NULL 2202.98 0.175 2347.52 0.07 0.23LHDH39 557 Muscovite NULL 2204.9 0.11 2343.44 0.08 0.09LHDH39 614 Muscovite Epidote 2211.37 0.061 2345.99 0.06 0.07LHDH39 660 Gypsum NULL NULL NULL 2337.5 0.05 0.06LHDH39 902 Muscovite IntChlorite 2210.88 0.094 2341.99 0.09 0.09LHDH39 902 Muscovite Phlogo-pite12208.09 0.071 2339.43 0.15 0.09LHDH39 949 Phlogopite NULL NULL NULL 2332.67 0.10 0.04LHDH39 949 Phlogopite NULL NULL NULL 2331.42 0.06 0.05LHDH39 983 Phlogopite NULL NULL NULL 2322.07 0.14 0.04LHDH45 200 Muscovite Gypsum 2206.3 0.206 2348.78 0.08 0.28LHDH45 537 Muscovite NULL 2208.02 0.267 2350.78 0.14 0.17LHDH49 450 Muscovite Gypsum 2203.41 0.176 2348.04 0.08 0.22LHDH49 450 Muscovite Gypsum 2205.46 0.172 2344.55 0.06 0.36OUT-CROPMuscovite Gypsum 2202.49 0.449 2347.89 0.21 0.40OUT-CROPIllite Prehnite 2198.26 0.241 2352.35 0.22 0.31196OUT-CROPMuscovite NULL 2209.11 0.154 2350.06 0.07 0.18OUT-CROPMuscovite Gypsum 2209.14 0.132 2344.33 0.07 0.18OUT-CROPPrehnite Epidote NULL NULL 2353.54 0.27 0.10OUT-CROPIllite NULL 2201.21 0.148 2344.61 0.08 0.24Illite Gypsum 2197.81 0.442 2345.48 0.18 0.35442505 6864686 Muscovite NULL 2202.86 0.362 2347.86 0.17 0.19442326 6864682 Muscovite NULL 2199.99 0.368 2346.73 0.17 0.11442326 6864682 Muscovite NULL 2200.58 0.384 2345.28 0.16 0.23442321 6864638 Muscovite Gypsum 2201.36 0.376 2346.89 0.16 0.33442340 6864630 Muscovite Gypsum 2207.53 0.125 2350.52 0.07 0.15442550 6864620 Muscovite Gypsum 2204.04 0.335 2349.1 0.14 0.33442600 6864620 Muscovite Gypsum 2204.03 0.334 2349.08 0.13 0.33442600 6864595 Illite Gypsum 2197.28 0.412 2344.23 0.16 0.40442810 6864513 Muscovite Gypsum 2208.82 0.216 2348.79 0.10 0.19442790 6864505 Muscovite Gypsum 2212.18 0.27 2349.76 0.10 0.34442790 6864505 Muscovite NULL 2211.54 0.223 2349.87 0.11 0.13442654 6864572 Muscovite Gypsum 2205.94 0.239 2348.56 0.14 0.22442654 6864572 Illite NULL 2197.63 0.412 2345.9 0.17 0.27442654 6864572 Illite NULL 2198.01 0.418 2345.34 0.17 0.28442654 6864572 Illite Gypsum 2198.58 0.395 2346.65 0.16 0.32442811 6864606 Muscovite NULL 2205.12 0.176 2346.12 0.08 0.15443122 6864988 Muscovite NULL 2199.41 0.431 2347.75 0.21 0.11442305 6864508 Illite NULL 2199.79 0.54 2345.16 0.26 0.30442305 6864508 Illite Jarosite 2200.65 0.344 2347.08 0.13 0.07197442334 6865294 Diaspore Gypsum NULL NULL 2359.16 0.02 0.34442334 6865294 Diaspore NULL NULL NULL NULL NULL 0.31442372 6865325 Diaspore Gypsum NULL NULL NULL NULL 0.27442372 6865325 Diaspore Gypsum NULL NULL 2349.36 NULL 0.31442417 6865537 Illite Phengite 2203.94 0.392 2347.58 0.21 0.13442417 6865496 Muscovite NULL 2211.92 0.27 2349.17 0.12 0.09442841 6864802 Illite Gypsum 2196.41 0.435 2344.31 0.16 0.41442841 6864802 Illite Gypsum 2196.63 0.398 2348.18 0.16 0.33442458 6864549 Muscovite Gypsum 2207.02 0.187 2343.38 0.04 0.49442557 6864512 Muscovite Gypsum 2206.68 0.155 2350.56 0.07 0.31442467 6864510 Illite NULL 2195.64 0.393 2343.29 0.16 0.23442467 6864510 Illite Gypsum 2195.88 0.397 2342.01 0.14 0.31442500 6464419 Muscovite Gypsum 2208.61 0.41 2348.47 0.19 0.38442488 6864418 Illite Gypsum 2207.18 0.212 2349.48 0.03 0.39442488 6864418 Gypsum Illite 2208.7 0.255 2345.18 NULL 0.55442469 6864418 Muscovite Gypsum 2205.17 0.236 2350.11 0.09 0.36442469 6864418 Muscovite Gypsum 2204.66 0.272 2349.04 0.12 0.38442450 6864415 Muscovite Gypsum 2204.13 0.38 2350.02 0.14 0.39442450 6864415 Muscovite NULL 2203.76 0.426 2348.84 0.19 0.20442428 6864407 Muscovite Gypsum 2211.27 0.177 2349.2 0.05 0.27442428 6864407 Muscovite NULL 2211.1 0.124 2351.34 0.06 0.17442414 6864401 Muscovite Gypsum 2202.44 0.251 2348.08 0.09 0.30442414 6864401 Muscovite Gypsum 2203.29 0.262 2345.28 0.09 0.28442410 6864385 Muscovite NULL 2202.55 0.381 2347.2 0.15 0.31442410 6864385 Muscovite Gypsum 2202.65 0.363 2345.46 0.13 0.43442409 6864364 Muscovite NULL 2203.36 0.427 2347.81 0.20 0.26442409 6864364 Muscovite Gypsum 2201.44 0.402 2347.06 0.14 0.39198442409 6864364 Muscovite Gypsum 2201.24 0.411 2346.69 0.16 0.37442409 6864324 IntChlorite Gypsum NULL NULL 2342.24 0.15 0.31442409 6864324 IntChlorite Gypsum NULL NULL 2343.45 0.10 0.29442384 6864310 Muscovite Jarosite 2210.28 0.261 2349.65 0.09 0.19442384 6864310 Phengite Illite 2211.26 0.278 2348.74 0.11 0.17442375 6864289 Muscovite Gypsum 2209.74 0.12 2343.89 0.11 0.19442375 6864289 Muscovite NULL 2210.52 0.241 2349.36 0.11 0.14442373 6864314 Muscovite NULL 2210.31 0.37 2348.4 0.17 0.28442348 6864383 4776 Muscovite NULL 2207.07 0.18 2347.67 0.06 0.25442336 6864431 4764 Muscovite Gypsum 2211.46 0.096 2344.7 0.06 0.27442336 6864431 Muscovite Gypsum 2211.25 0.094 2346.89 0.03 0.29442357 6864465 4746 Illite Jarosite 2199.92 0.345 2345.95 0.11 0.12442406 6864496 4742 Muscovite Gypsum 2205.42 0.302 2350.81 0.14 0.35442406 6864496 Muscovite NULL 2204.82 0.3 2348.66 0.16 0.18442477 6864512 4743 Muscovite Gypsum 2201.24 0.448 2347.44 0.19 0.45442477 6864512 Illite Gypsum 2201.25 0.422 2346.57 0.17 0.44442557 6864516 4738 Muscovite NULL 2209.25 0.175 2349.55 0.08 0.21442557 6864516 Muscovite NULL 2210.13 0.14 2351.04 0.09 0.12442557 6864516 Muscovite NULL 2210.21 0.144 2351.01 0.08 0.12442324 6864423 4747 Muscovite Gypsum 2209.26 0.266 2348.99 0.07 0.37442324 6864423 Muscovite Gypsum 2211.06 0.3 2349.53 0.06 0.50442311 6864441 4741 Muscovite NULL 2208.88 0.197 2348.97 0.10 0.17442311 6864441 Muscovite Siderite 2209.2 0.131 2347.08 0.06 0.16442410 6864543 4714 Muscovite Gypsum 2209.1 0.178 2347.77 0.03 0.45442410 6864543 Muscovite Gypsum 2208.44 0.189 2344.6 0.05 0.43442499 6864568 4714 Illite Gypsum 2200.52 0.333 2347.12 0.08 0.34442499 6864568 Muscovite Gypsum 2199.89 0.416 2345.93 0.17 0.38199442592 6864592 Muscovite Gypsum 2206.2 0.255 2348.96 0.13 0.33442592 6864592 Muscovite Gypsum 2210.73 0.199 2343.87 0.05 0.39442688 6864551 4680 Muscovite Gypsum 2206.23 0.272 2350.68 0.11 0.32442688 6864551 Muscovite NULL 2205.96 0.249 2349.36 0.13 0.22442775 6864610 4686 Muscovite Gypsum 2201.17 0.402 2348.62 0.16 0.35442775 6864610 Muscovite Gypsum 2200.38 0.391 2348.13 0.15 0.36442746 6864496 4714 Muscovite Gypsum 2203.38 0.411 2346.69 0.16 0.45442746 6864496 Muscovite Gypsum 2203.26 0.369 2347.06 0.13 0.42442684 6864551 4679 Muscovite Gypsum 2204.61 0.274 2348.93 0.12 0.24442684 6864551 Muscovite NULL 2203.29 0.337 2348.88 0.16 0.21442215 6864592 4634 Muscovite NULL 2203.04 0.403 2347.72 0.19 0.18442215 6864592 Muscovite Jarosite 2204.36 0.223 2347.45 0.08 0.11442858 6864817 4553 Muscovite Jarosite 2208.39 0.101 2350.61 0.01 0.15442858 6864817 Muscovite NULL 2208.39 0.17 2346.79 0.07 0.13442079 6863804 4739 Illite Kaolinite 2207.85 0.195 2351.24 0.09 0.27442079 6863804 FeChlorite Illite 2208.91 0.105 2352.01 0.09 0.22442173 6863737 4800 Illite Gypsum 2212 0.146 2349.48 0.03 0.32442173 6863737 Illite Gypsum 2211.22 0.094 2350.7 0.01 0.26442173 6863737 Illite NULL 2207.49 0.054 2354.4 0.03 0.19442216 6863830 4801 Illite NULL 2207.93 0.053 2354.56 0.03 0.15442216 6863830 Illite NULL 2197.85 0.461 2344.85 0.21 0.43442199 6863662 4845 Illite NULL 2196.74 0.401 2344.56 0.15 0.36442077 6863585 4853 Illite Jarosite 2201.31 0.251 2345.55 0.04 0.15442163 6863550 4908 Illite Phengite 2210.58 0.338 2346.54 0.20 0.25442158 6863500 4925 Illite Phengite 2210.09 0.27 2347.96 0.13 0.23442288 6863519 4953 Illite Phengite 2209.01 0.222 2349.08 0.10 0.27442288 6863519 4925 Muscovite Ankerite 2208.32 0.086 2344.18 0.06 0.17200442288 6863519 4953 Illite Phengite 2202.71 0.374 2345.65 0.19 0.19442288 6863519 4953 Illite NULL 2201.95 0.319 2346.6 0.14 0.19442748 6863737 5128 Siderite Muscovite 2207.49 0.033 2345.94 0.03 0.10442748 6863737 5128 Muscovite Ankerite 2204.77 0.147 2341.49 0.09 0.16442853 6863784 5144 Kaolinite K_Alunite 2208.66 0.141 2320.82 0.03 0.06442853 6863784 5144 Kaolinite K_Alunite 2208.66 0.191 2321.21 0.05 0.08442662 6864017 5028 Illite Paragonite 2195.93 0.31 2343.2 0.11 0.10442662 6864017 5028 Illite Paragonite 2195.82 0.285 2341.99 0.09 0.08442634 6864107 4975 Illite NULL 2198.57 0.282 2345.88 0.10 0.12442634 6864107 4975 Muscovite Jarosite 2200.6 0.186 2352.19 0.03 0.17442634 6864107 4975 Illite Jarosite 2197.64 0.38 2346.07 0.09 0.15442634 6864107 4975 Illite Jarosite 2197.35 0.331 2346.03 0.12 0.14443346 6865216 4520 Muscovite Gypsum 2201.81 0.202 2346.86 0.08 0.22443740 6864980 4761 FeChlorite Brucite 2208.99 0.028 2348.52 0.05 0.06443740 6864980 4761 Illite Gypsum 2200.04 0.326 2342.42 0.06 0.48443740 6864980 4761 IntChlorite Muscovite 2211.58 0.079 2348.45 0.08 0.14443740 6864980 4761 Muscovite Ankerite 2203.91 0.083 2347.64 0.05 0.16443765 6864944 4944 Epidote NULL 2207.4 0.031 2333.29 0.04 0.08442424 6865951 4367 FeTourma-lineHalloysite 2206.33 0.072 2319.5 NULL 0.11442276 6863454 4969 Muscovite NULL 2204.1 0.146 2350 0.08 0.11442276 6863454 4969 MgChlorite NULL 2229.21 0.026 2331.71 0.07 0.07442276 6863454 4969 Siderite FeTourma-line2202.59 0.029 2324.88 0.07 0.07442276 6863454 4969 Opal Jarosite 2208.31 0.073 2300.25 NULL 0.17442276 6863454 4969 Diaspore NULL 2207.23 0.099 NULL 0.04 0.22442276 6863454 4969 Jarosite NULL 2228.45 0.096 NULL NULL 0.20201442276 6863454 4969 Jarosite Gypsum 2211.38 0.069 NULL NULL 0.24442276 6863454 4969 FeTourma-lineBrucite 2202.14 0.068 2330.85 0.09 0.09442276 6863454 4969 Jarosite Gypsum 2203.01 0.047 NULL NULL 0.17442276 6863454 4969 Jarosite NULL 2205.69 0.057 NULL NULL 0.12442276 6863454 4969 Jarosite NULL 2204.56 0.052 2302.4 NULL 0.17442276 6863454 4969 Jarosite Gypsum 2202.4 0.047 NULL NULL 0.14442246 6863497 4941 Muscovite Kaolinite 2206.91 0.226 2350.5 0.08 0.17443347 6865417 4506 Muscovite NULL 2201.64 0.33 2347.6 0.15 0.22443347 6865417 4506 Muscovite NULL 2201.86 0.373 2346.54 0.18 0.26442821 6864527 4712 Muscovite Gypsum 2207.66 0.161 2350.81 0.05 0.24442821 6864527 4712 Muscovite NULL 2207.77 0.124 2349.56 0.05 0.16442821 6864527 4712 Muscovite Gypsum 2203.96 0.321 2350.04 0.14 0.26442821 6864527 4712 IntChlorite Muscovite 2207.09 0.153 2344.16 0.13 0.19442743 6864483 4712 IntChlorite Muscovite 2205.43 0.151 2347.31 0.15 0.17442743 6864483 4712 Muscovite NULL 2204.16 0.147 2344.43 0.05 0.12442743 6864483 4712 Muscovite NULL 2204.83 0.175 2346.68 0.08 0.13442743 6864483 4712 Muscovite NULL 2202.67 0.395 2347.3 0.18 0.31442743 6864483 4712 Muscovite Gypsum 2204.11 0.342 2349.12 0.15 0.33442790 6864601 4711 Muscovite Gypsum 2199.3 0.381 2344.97 0.13 0.38442790 6864601 4711 Illite Gypsum 2200.7 0.366 2348.05 0.13 0.33442790 6864601 4711 Illite Gypsum 2200.23 0.363 2349.74 0.14 0.33442702 6864538 4676 Muscovite Gypsum 2209.5 0.118 2346 0.04 0.24442702 6864538 4676 Illite NULL 2207.47 0.067 2352.96 0.03 0.13442522 6864630 4712 Muscovite Gypsum 2209.16 0.091 2348.28 0.06 0.20442361 6864635 4712 Muscovite NULL 2202.78 0.233 2346.91 0.10 0.18442495 6864682 4712 Illite NULL 2206.91 0.054 2347 0.02 0.09202Appendix E: X-Ray Diffraction (XRD)203X-Ray Diffraction (XRD) was used as support for petrography, short-wave Infrared spectroscopy results, and alteration assemblages. Twelve samples were analyzed.  XRD was conducted using a standard Siemens (Bruker) D5000 Bragg-Brentano diffractometer at the Department of Earth, Ocean and Ocean Sciences (EOAS), of The University of British Columbia (UBC), at Vancouver, BC, Canada. The diffraction spectra of the samples were compared to ICDD databases found in the EVA software in order to identify alteration minerals within each analyzed sample. Twelve samples were analyzed.Abbreviations: Al: albite; Chl; chlorite; Gyp: gypsum; Ill: illite; Kao: kaolinite; Kfs: potassic feldspar; Qz: quartz; Mg: magnetite; Musc; muscovite; Py: pyrite. MRBX: Matrix Rich Breccia; CBX: Cement Rich Breccia; FPR: Feldspar Phyric Rhyodacites.Hole ID Depth Lithology AlterationSWIR XRDWhite mica ALOH (nm) KI Minerals identifiedLHDH20150 FPR SER Paragonite-Musc 2197.76 0.148 Musc-Gyp-Py- Qz290 FPR SER Paragonite-Musc 2198.91 0.151 Musc-Ill-Gyp-Py-Qz330 FPR SCM Musc 2200.95 0.169 Musc-Gyp-Py- Qz590 CBX SCM Musc 2204.31 0.238 Musc-Gyp-Py- Qz- Kao640 CBX KK Phentitic-Musc 2207.41 0.131 Musc-Gyp-Py- Chl-Qz720 CBX KK Phentitic-Musc 2208.76 0.171 Musc-Gyp- Chl-Qz-Al LHDH2460 GRN SER Paragonite-Musc 2194.33 0.148 Musc-Gyp-Hem- Qz-Alcop130 GRN SER Paragonite-Musc 2192.89 0.159 Musc-Ill-Gyp-Py- Qz290 FPR SCM Musc 2202.54 0.162 Musc-Gyp-Py- Qz-Chl-Al380 MRBX SCM Phentitic-Musc 2207.7 0.159 Musc-Gyp-Py- Qz-Chl460 MRBX SCM Phentitic-Musc 2210.22 0.167 Musc-Gyp-Py- Qz-Chl-Al-Mg630 MRBX KK Phentitic-Musc 2205.87 0.132 Musc-Gyp-Qz-Chl-Al-Mg700 MRBX KK Musc 2207.32 0.127 Musc-Gyp-Py-Qz-Chl-KfsTable E1: Comparison between SWIR and XRD data. SWIR data shows the 2200 nm absorption feature and the composition of the with micas. XRD data shows the Kübler Index (see section 5.5.1) and the minerals identified.  204Figure E1: X-ray pattern form Los Helados drill hole. LHDH20 at 150 m.205Figure E2: X-ray pattern form Los Helados drill hole. LHDH20 at 330 m. 206Figure E3: X-ray pattern form Los Helados drill hole. LHDH20 at 330 m.207Figure E4: X-ray pattern form Los Helados drill hole. LHDH20 at 590 m.208Figure E5: X-ray pattern form Los Helados drill hole. LHDH20 at 640 m.209Figure E6: X-ray pattern form Los Helados drill hole. LHDH20 at 720 m.210Figure E7: X-ray pattern form Los Helados drill hole. LHDH24 at 60 m211Figure E8: X-ray pattern form Los Helados drill hole. LHDH24 at 130 m.212Figure E9: X-ray pattern form Los Helados drill hole. LHDH24 at 290 m.213Figure E10: X-ray pattern form Los Helados drill hole. LHDH24 at 460 m.214Figure E11: X-ray pattern form Los Helados drill hole. LHDH24 at 630 m.215Figure E12: X-ray pattern form Los Helados drill hole. LHDH24 at 700 m.216Appendix F:   Drill core logging217This section shows an example of the drill hole logging method using for Los Helados. Mapping and drill core logging methodology for this research was based on a slightly modified Anaconda method (Einaudi, 1997). Twelve complete drill holes and numerous intercepts were logged total-ing more than 15000 m . For this research, the data collection was focused on vein types, geome-try, mineral composition, alteration assemblage, and rock type.  Figure F1: Examples of drillcore logging. 218219220221222223224Appendix G:   Drill Holes225Table G1:  Drill hole location, altitude, azimuth, dip and depth.Hole ID UTM-19S-E UTM-19S-N Altitude Azimut Dip DepthLHRC39 442422 6865774 4464 0 -90 254.00LHRC40 442435 6864639 4643 110 -80 300.00LHRC41 442696 6864992 4495 90 -80 300.00LHRC42 442425 6865408 4582 270 -80 292.00LHRC43 443098 6865402 4423 0 -90 174.00LHRC44 443067 6865996 4341 270 -75 50.00LHRC45 442302 6864995 4537 270 -80 300.00LHDH01 442618 6864814 4536 90 -80 530.45LHDH02 442586 6864593 4675 90 -90 506.45LHDH03 442341 6864634 4645 180 -80 750.20LHDH04 442851 6864814 4545 270 -75 779.00LHDH05 442683 6865235 4468 0 -75 869.15LHDH06 442850 6865054 4475 270 -75 764.60LHDH07 443023 6865388 4410 0 -75 800.15LHDH08 443018 6865174 4464 90 -75 755.15LHDH09 442798 6865800 4388 270 -75 476.15LHDH10 442523 6864310 4827 270 -75 351.00LHDH11 443350 6865436 4483 90 -75 491.15LHDH12 442700 6864997 4492 270 -75 751.00LHDH13 442398 6864800 4575 90 -75 742.30LHDH14 442999 6865110 4470 270 -80 1384.55LHDH15 442875 6865199 4448 270 -75 711.00LHDH16 442660 6864900 4516 270 -75 777.00LHDH17 442803 6864895 4522 270 -75 1205.10LHDH18 442678 6864701 4590 270 -75 695.40LHDH19 442502 6864690 4611 270 -75 1028.00LHDH20 442922 6864877 4537 270 -75 750.00LHDH21 442530 6864904 4527 270 -75 750.00LHDH21 442530 6864904 4527 270 -75 1507.05LHDH22 442557 6865004 4513 270 -75 1306.30LHDH23 442406 6864895 4555 270 -75 1016.50LHDH24 442279 6864801 4570 90 -75 937.80LHDH25 442268 6864902 4559 270 -75 500.70LHDH26 442003 6864795 4580 90 -80 1185.65LHDH27 442199 6864799 4584 90 -80 1175.00LHDH28 442201 6864895 4568 270 -75 1018.60LHDH29 442222 6864986 4541 270 -75 982.50LHDH30 442596 6865193 4497 270 -75 1010.00LHDH31 442907 6865001 4489 270 -75 1000.00226Hole ID UTM-19S-E UTM-19S-N Altitude Azimut Dip DepthLHDH33 442195 6865094 4561 270 -75 1012.90LHDH34 442199 6864699 4594 270 -75 978.20LHDH35 442800 6865099 4462 270 -75 1042.50LHDH36 442408 6865002 4537 270 -75 675.00LHDH37 441801 6864703 4681 0 -90 1206.50LHDH38 442407 6865210 4537 270 -75 1001.50LHDH39 442921 6864882 4537 0 -90 1029.20LHDH40 442598 6865093 4490 270 -75 1000.00LHDH41 442209 6865198 4592 270 -75 985.00LHDH42 442750 6864607 4657 0 -90 848.40LHDH43 442599 6865296 4493 270 -75 943.10LHDH44 442356 6865109 4531 270 -75 1023.20LHDH45 442004 6864893 4581 270 -75 641.00LHDH46 442357 6864694 4625 270 -75 1247.20LHDH47 442800 6865300 4446 270 -75 248.40LHDH48 442592 6864498 4727 90 -75 1213.50LHDH49 442079 6864899 4560 270 -75 1158.70LHDH50 442403 6865210 4537 180 -60 1270.80LHDH51 441918 6864606 4617 90 -85 1500.00LHDH52 442808 6864658 4624 270 -78 1193.50LHDH53 443029 6865004 4508 270 -78 860.60LHDH54 442305 6864508 4706 90 -75 1198.65LHDH55 442593 6865296 4493 180 -60 1291.80LHDH56 441899 6864794 4603 90 -82 1180.60LHDH57 442598 6864496 4727 180 -60 797.80LHDH58 442049 6864595 4608 90 -75 1326.05LHDH59 442805 6864521 4727 180 -60 1233.10LHDH60 442342 6864629 4645 90 -75 185.75LHDH61 442929 6864772 4605 90 -75 1252.95LHDH62 442618 6865414 4492 270 -75 1447.00LHDH63 442115 6864012 4676 90 -60 1255.00LHDH65 442807 6864521 4722 90 -75 1183.65LHDH66 442107 6864207 4641 25 -60 1323.30LHDH67 442107 6864390 4618 270 -70 909.30LHDH68 443352 6865437 4483 270 -75 1236.05LHDH69 442804 6864659 4624 0 -90 1155.45LHDH70 442203 6865396 4556 270 -75 1089.30LHDH71 442928 6864772 4605 270 -80 1301.70LHDH72 442700 6864850 4533 270 -75 1100.00227Figure G1:  Drill hole location and drill hole traces.

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