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Cretaceous porphyry magmatic-hydrothermal systems in the Tchaikazan River area, southwest B.C Hollis, Lucy 2009

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CRETACEOUS PORPHYRY MAGMATIC-HYDROTHERMAL SYSTEMS IN THE TCHAIKAZAN RIVER AREA, SOUTHWEST B.C. by Lucy Hollis M.Sci. (Hons), University of Birmingham, 2006 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in The Faculty of Graduate Studies (Geological Sciences) THE UNIVERISTY OF BRITISH COLUMBIA (Vancouver) April 2009 © Lucy Hollis ABSTRACT The Hub, Charlie and Northwest Copper are spatially related mineral showings (Cu ± Mo) located in the Tchaikazan River area of southwest British Columbia. The Tchaikazan River area is located on the boundary between the Intermontane Belt and southeast Coast Belt (SECB). Evidence of magmatic-hydrothermal alteration is preserved throughout the study area. Multiple episodes of magmatic-hydrothermal activity are associated with these three centres of porphyry-style mineralization. The Hub diorite is the oldest dated pluton in the area, with a U-Pb zircon emplacement age of 81.19 ± 0.78 Ma. ZFT/AFT data suggests an emplacement depth of> 4km for the Hub diorite. The Hub diorite is crosscut by a biotite ± magnetite (± quartz) matrix/cemented hydrothermal breccia. A feldspar hornblende dyke crosscuts both the diorite and hydrothermal breccia and gives a U-Pb zircon age of 79.9 ± 1.5 Ma. Copper, molybdenite ± galena occurs in quartz veining and cement to the hydrothermal breccia. ZFT/U-Pb and Ar-Ar ages for the Hub diorite are within error of each other. AFT data suggests an average erosion rate of 40 m!myr for intrusive rocks in the Taseko Lakes area. Field relationships, geophysical anomalies, geochronology, and stable isotope data suggest that there are three centres for magmatic-hydrothermal activity in the Tchaikazan River area: The Hub, Northwest Copper pluton, and Ravioli Ridge. The area displays evidence for multiple, temporally-distinct intrusive, alteration and mineralizing events. 11 Abstract.ii TABLE OF CONTENTS iii List of Tables viii List of Figures viiii Acknowledgements xiv CHAPTER I 16 INTRODUCTION 16 1.1 INTRODUCTION 16 1.2 MAGMATIC-HYDROTHERMAL SYSTEMS IN THE SOUTHERN COAST MOUNTAINS, B.C 16 1.3 RESEARCH GOALS 17 1.4 RESEARCH APPROACH 18 1.5 STUDY AREA 20 1.6 PREVIOUS GEOLOGICAL RESEARCH AND MINERAL EXPLORATION 21 1.7 THESIS STRUCTURE 24 CHAPTER II 28 REVIEW OF PORPHYRY MAGMATIC-HYDROTHERMAL SYSTEMS 28 2.1 INTRODUCTION 28 2.2 SIZE 28 2.3 SPATIAL DISTRIBUTION 28 2.4 TEMPORAL DISTRIBUTION 29 2.5 GEOLOGICAL ATTRIBUTES 30 2.5.1 Geological setting and related magmatic rocks 30 2.5.2 Morphology 30 2.5.3 Structure 31 2.5.4 Hydrothermal alteration 31 2.5.5 Mineralization 33 2.5.6 Fluid Evolution 33 111 2.5.7 Porphyry to epithermal continuum .35 CHAPTER III 42 GEOLOGICAL AND GEOCHRONOLOGICAL FRAMEWORK OF MAGMATIC-HYDROTHERMAL ACTIVITY IN THE TCHAIKAZAN RIVER AREA 42 3.1 REGIONAL GEOLGIC SETTING 42 3.2 LOCAL GEOLOGIC SETTING - FIELD OBSERVATIONS 43 3.2.1 Tchaikazan River Formation 44 Volcanic facies 44 Volcano-sedimentary facies 44 Sedimentary facies 45 3.2.2 Powell Creek Formation 46 Coherent facies 46 Non-massive facies 46 3.2.3 Intrusive rocks 48 Hub Intrusive Complex 49 Northwest Copper Intrusive Complex 49 Other Intrusive Rocks 50 Subsurface Intrusive Rocks 51 3.3 REGIONAL METAMORPHISM 51 3.4 STRUCTURAL GEOLOGY OF THE FIELD AREA 52 3.4.1 Large thrust faults 52 3.4.2 Large normal faults 53 3.4.3 Other large faults (unknown displacement) 54 3.4.4 Small-scale structures (faults, fractures, veins) 54 3.4.5 The Tchaikazan fault 55 3.5 GEOCHRONOLOGY 55 40Ar-39rGeochronology 56 U-Pb Geochronology 56 3.5.1 Discussion 57 3.6 FISSION-TRACK THERMOCHRONOLOGY 58 iv 3.6.1 Introduction .58 3.6.2 Methodology 59 3.6.3 Results 59 3.6.4 Interpretation 59 CHAPTER IV 89 PALAEOGEOGRAPHY AND TECTONIC SETTING OF THE TCHAIKAZAN RIVER AREA 89 4.1 LOCAL PALAEOGEOGRAPHICAL SETTING 89 4.2 TECTONIC DEVELOPMENT 91 4.3 FELSIC INTRUSION HISTORY 92 4.4 EXHUMATION 93 CHAPTER V 98 PHYSIO-CHEMICAL MANIFESTATIONS OF MAGMATIC HYDROTHERMAL SYSTEMS IN THE TCHAIKAZAN RIVER AREA 98 5.1 DEPOSIT SCALE FRAMEWORK OF PORPHYRY MINERALIZATION 98 5.2 GEOLOGICAL SETTING 98 5.2.1 The Hub Porphyry 98 5.2.2 Charlie-Northwest Copper 99 5.3 HYDROTHERMAL ALTERATION 99 5.3.1 The Hub Porphyry 100 Hydrothermal Breccia 100 Magnetite ± biotite alteration 100 Sericite alteration 101 Chlorite ± epidote alteration 101 Silicification 101 5.3.2 Charlie-Northwest Copper 102 Propylitic alteration assemblage 102 Phyllic alteration 103 Kaolinite—dickite—illite alteration (Advanced Argillic) 103 V Quartz-diaspore assemblage (Advanced Argillic) 104 Silicification 104 5.4 PARAGENESIS 104 5.4.1 Hub 105 5.4.2 Charlie-Northwest Copper 105 5.5 ORE ASSEMBLAGES 106 5.5.1 Hub 106 5.5.2 Charlie-Northwest Copper 107 5.6 AGE OF MINERALIZATION 108 5.6.1 Hub 108 5.6.2 Charlie-Northwest Copper 109 5.7 FLUID INCLUSION MICROTHERMOMETRY 110 5.7.1 Sampling and analytical techniques 110 5.7.2 Description of fluid inclusions from the Hub porphyry deposit 110 5.7.3 Description of fluid inclusions from the Charlie-Northwest Copper area 111 5.7.4 Discussion 112 5.8 STABLE ISOTOPE STUDY 112 5.8.1 Sampling and analytical techniques 113 Carbonate stable isotope analyses 114 Oxygen and Hydrogen stable isotope analyses 114 5.8.2 The Hub porphyry deposit 114 Oxygen stable isotope analysis of quartz veins 114 Oxygen stable isotope analysis of quartz-magnetite 115 Oxygen stable isotope analysis of magnetite 115 5.8.3 Charlie-Northwest Copper 115 Carbonate stable isotope analysis of calcite veins 115 Oxygen stable isotope analysis of quartz veins 116 Oxygen stable isotope analysis of quartz-magnetite veins 116 Hydrogen and Oxygen stable analysis of kaolinite alteration 116 5.8.4 Discussion and Interpretation 117 vi CHAPTER VI .144 GENESIS AND EVOLUTION OF THE MAGMATIC - HYDROTHERMAL SYSTEM IN THE TCHAIKAZAN RIVER AREA 144 6.1 THE TCHAIKAZAN RIVER AREA - A LINKED MAGMATIC-HYDROTHERMAL SYSTEM(S) 144 The Hub porphyry deposit 144 Ravioli Ridge 148 Northwest Copper pluton 150 Distal hydrothermal alteration 151 Interpretation of hydrothermal systems within a porphyry-epithermal continuum 151 CHAPTER VII 156 INTEGRATED GEOLOGICAL EVOLUTION OF THE TCHAIKAZAN RIVER AREA: Conclusions and Implications 156 REFERENCES 160 APPENDICES 169 Appendix 1: DRILL LOGS 169 Appendix 2: FULL DATA SET FOR GEOCHRONOLOGY STUDY 215 Appendix 3: FLUID INCLUSION MICROTHERMOMETRY 223 vii LIST OF TABLES CHAPTER III Table 3.1 Table of the volcano-sedimentary facies observed in the Powell Creek Formation 67 Table 3.2 Summary of geochronological age dates from the Tchaikazan River area 81 Table 3.3 Summary of collected thermochronology samples 85 CHAPTER V Table 5.1 Summary of the styles of mineralization and paragenesis 120 Table 5.2 Summary of the veins and hydrothermal alteration at the Hub porphyry deposit 129 Table 5.3 Summary of the veins and hydrothermal alteration in the Charlie-Northwest Copper area 134 Table 5.4 Summary of silicate vein samples for 0 stable isotope analysis 139 Table 5.5 Summary of calcite vein samples for C and 0 isotope analysis 142 vii’ LIST OF FIGURES PLATE I Geological map of the Tehaikazan River area, Hub trench map, and stratigraphic section through part of the Powell Creek See insert CHAPTER I Figure 1.1 Map of Canada showing the distribution of selected porphyry deposits, illustrating their metallogenic affinity and size 26 Figure 1.2 Map of British Columbia, with study area and highlighting proximal magmatic-hydrothermal deposits 27 CHAPTER II Figure 2.1 A) Graph showing the world’s 25 largest porphyry deposits, in terms of grade (Cu wt %) and tonnage (Mt) and B) Graph showing the ages of the 25 largest porphyry deposits in the world (Simplified from Cooke et al., 2005) 36 Figure 2.2 Schematic relationships between depth and age-frequency distributions. From Kesler and Wilkinson, 2005 37 Figure 2.3 A) Cross section through a subduction zone and continental arc. B) Schematic cross section through a porphyry Cu-forming volcano plutonic system (From Richards, 2003) 38 Figure 2.4 Hypothesized vertical cross section through a model porphyry system: A) Zonation of hydrothermal mineral assemblages and, B) Distribution of sulfide minerals. (Simplified from Lowell and Guilbert, 1970) 39 Figure 2.5 Map of the Ann-Mason porphyry copper deposits, Nevada. Hydrothermal alteration mineral zoning is shown, plus hypothesized fluid flow pathways. Simplified from Dilles and Einaudi, (1992) 40 Figure 2.6 Schematic cross sections illustrating three potential fluid evolution regimes, which may occur separately above a magma chamber emplaced at different depths or develop sequentially during the evolution of a single, ix vertically extensive porphyry to epithermal system (Modified from Williams-Jones and Heinrich, 2005) 41 CHAPTER III Figure 3.1 Stratigraphic relationships in the Tchaikazan River study area: A) Regional geology map showing the distribution of terranes and regional fault system - Modified from Israel Ct al., (2006). Study area highlight by hatched rectangle. B) Stratigraphic chart to accompany Figure 3.1A 61 Figure 3.2 Schematic summary of the tectonic setting and inferred sediment sources of the Early to mid-Cretaceous rocks in the Tyaughton-Methow basin (From Blevings, 2008) 62 Figure 33 Geological map of the Tchaikazan River area 63 Figure 3.4 Geological legend to accompany figure 3.3 64 Figure 3.5 Photoplate of the Tchaikazan River Formation: sedimentary facies 65 Figure 3.6 Photoplate of the varied volcanic textures exhibited by the Powell Creek Formation 66 Figure 3.7 Stratigraphic section through part of the Powell Creek dominated by resedimented units 68 Figure 3.8 Geology map of the Hub porphyry trenches and location of drillholes O8TSK-02, 03, 04 and 06, drillholes sighted towards 320° at — 60°and-65° 69 Figure 3.9 Photoplate with igneous textures associated with the Hub diorite 70 Figure 3.10 Interpreted geological cross sections through part of the Hub porphyry deposit 71 Figure 3.11 Photoplate showing the igneous rocks attributed to the Northwest Copper pluton 72 Figure 3.12 Photoplate showing the Northwest Copper syenite and associated igneous textures 73 Figure 3.13 Photoplate of other intrusive rocks in the Tchaikazan River area 74 Figure 3.14 Geological cross sections through of the Tchaikazan River area 75 x Figure 3.15 Magnetic anomaly map with interpreted geological contacts and facies distributions illustrated 76 Figure 3.16 Photoplate of an exposure of the Northwest Copper thrust fault 77 Figure 3.17 Photoplate of features associated with Northwest Copper thrust fault 78 Figure 3.18 Photoplate, taken facing north; showing the Charlie area (left) comprised of coherent andesite of the Tchaikazan River Formation, juxtaposed against the younger Powell Creek Formation by the Northwest Copper thrust fault 79 Figure 3.19 Equal-area, lower hemisphere stereonet plots showing the orientation of veins in the Charlie-Northwest Copper areas 80 Figure 3.20 Ar-Ar plateau ages for representative intrusive rocks from the Tchaikazan River area 82 Figure 3.21 U-Pb geochronology diagrams for samples of intrusive rock from the Tchaikazan River area 83 Figure 3.22 Summary diagram for radiogenic isotope geochronology for the Tchaikazan River area 84 Figure 3.23 Plot showing all age data for the suite of samples form the Taseko Lakes area 86 Figure 3.24 Thermochronology analysis on the Taseko Lakes sample suite 87 Figure 3.25 Schematic diagram illustrating the emplacement and exhumation history of the Tchaikazan River area 88 CHAPTER IV Figure 4.1 Tectonic evolution for the Southeast Coast Belt (SECB) and Tchaikazan River area. (Modified from Israel et al., 2006) 94 Figure 4.2 Reconstruction of the volcano-sedimentary system within the Tchaikazan River area, including major facies associations and tectonic setting (Modified from Israel, 2001) 95 Figure 4.3 Schematic reconstruction of the volcanic facies of the Powell Creek Formation: primary volcanic, resedimented volcanic rocks and volcaniclastic rocks 96 xi Figure 4.4 Schematic reconstruction of the development of thrust faults through the Tchaikazan River area 97 CHAPTER V Figure 5.1 Schematic map of observed hydrothermal mineral assemblages in the Tchaikazan River area; compiled data from mineral mapping, in addition to SWIR analysis 119 Figure 5.2 Map of the Hub porphyry trenches. Pervasive hydrothermal alteration is mapped, including sericite-chiorite, chiorite-epidote and biotite ± magnetite alteration 121 Figure 5.3 Comparison of features observed from drill core and surface outcrop within the biotite ± magnetite-cemented hydrothermal breccia 122 Figure 5.4 Hand specimen slab from the Hub hydrothermal breccia 123 Figure 5.5 Photoplate of biotite ± magnetite alteration in the Hub porphyry system 124 Figure 5.6 Photoplate of other styles of alteration in the Hub porphyry deposit: sericite, chlorite-epidote, and silicification 125 Figure 5.7 Photoplate of the styles of alteration in the Charlie-Northwest Copper area 126 Figure 5.8 Photoplate of advanced argillic alteration on the western flank of Ravioli ridge 127 Figure 5.9 Slab from the quartz diaspore area of alteration with textural and compositional features 128 Figure 5.10 Photoplate of hand and thin sections of the veins within Charlie-Northwest Copper area 130 Figure 5.11 Photoplate showing the styles of veining at the Hub porphyry system...131 Figure 5.12 Photoplate illustrating the major styles of mineralization observed in the Hub porphyry intrusive complex 132 Figure 5.13 Photoplate of backscatter SEM images from the Hub porphyry deposit 133 xii Figure 5.14 Photoplate of the variation in vein types, composition, alteration and textures from veins within Charlie-Northwest Copper area. 135 Figure 5.15 Photoplate showing the styles of mineralization in the Charlie-Northwest Copper area 136 Figure 5.16 Schematic paragenetic relationship diagrams for: A) the Hub porphyry deposit and B) Charlie-Northwest Copper area 137 Figure 5.17 Photomicrographs of thick sections for fluid inclusion analysis 138 Figure 5.18 Oxygen isotope data from powdered quartz vein samples for the Hub, Charlie and Northwest Copper 140 Figure 5.19 Oxygen and carbon isotope data from powdered calcite veins from the Charlie-Northwest Copper area: A) Map of the study area showing the location of isotope samples collected for analysis using carbon and oxygen stable isotopes, and B) Oxygen and carbon isotopic data for calcite veins from the study area 141 Figure 5.20 Quartz-magnetite mineral pair from vein in the Northwest Copper area, illustrating fractionation factors and corresponding temperatures based on quartz-magnetite geothermometry 143 CHAPTER VI Figure 6.1 Schematic model for the evolution of the Hub porphyry deposit 153 Figure 6.2 Schematic model for the establishment of a magmatic-hydrothermal system beneath the Ravioli ridge in the Northwest Copper area 154 Figure 6.3 Eh-pH diagram showing the stability fields of selected copper minerals 155 CHAPTER VII Figure 7.1 Schematic integrated geological evolution of the Tchaikazan River area 159 xiii ACKNOWLEDGEMENTS My supervisor Dr Ken Hickey has provided scientific support and guidance, plus many in-depth, mind-bending discussions for which I am thankful. I will always remember him loitering near the chocolate machine, often peeved about the lack of Mars bars. Lori Kennedy is thanked for being the primary supervisor for the first year of the project and providing a wealth of knowledge concerning all things structural. Both are thanked for partaking in memorable boulder rolling and sample-bag sledding during field visits. Galore Resources Inc. provided both funding and logistical support during fieldwork. Geoscience BC is a non-profit organization that is industry-led and provided financial backing for analytical procedures that contributed greatly to the final project. As for all those grad students, too many to mention here, all of whom were more than willing to participate in debates (sometimes geology-related) over several pints at twoonie Tuesday (you know who you are) — see you next Tuesday! It was a pleasure to have Scott Blevings as a field partner, lab mate and friend throughout my time at UBC - thanks big buddy. Thanks to Rosie, RE, and Jackie, who were all pillars of support throughout my M.Sc experience. Special thanks to Jenni; an all-round, amazing friend - you were by my side when I was floundering, always encouraging me to jump back in and swim against the tide. From night’s in sipping on pop, watching truly crap tv, to trips to G.I. In the last months I truly appreciated all those meals on wheels you prepared. And yes, I even appreciated inserting every last comma in those final edits of yours so a big thank you. Truthfully, I will treasure my years at UBC, surrounded by an eclectic bunch of scientists, students, friends and fellow sufferers. Last, but not least, I’d like to say a big thank you to my parents, without whose encouragement, and unconditional, unrelenting support I would never have made it this far. Thank you. xiv DEDICATION ‘Tb myparents. Ifyou canfiCCtuIe unforgIvIng mInute ‘WIth sIxty secon6s’ worth of distance run, yours Is the Earth antieverything that’s In It, Anti- which Is more - you’1TIe a Man, my son! -X4Cing xv CHAPTER I INTRODUCTION 1.1 INTRODUCTION Porphyry deposits are the major source of the world’s Cu and Mo (Sinclair, 2007). They are large hydrothermal systems intimately related to the exsolution of fluids from magma intruded into high levels of the Earth’s crust. Tectonic environments, magma composition, and crustal environment of emplacement all play a role in determining the metal endowment of these deposits (Richards, 2003). From the distribution of porphyry deposits around the world it is clear that the magmatic-hydrothermal systems responsible for their genesis occur in pulses that are restricted in both time and space. Canadian porphyry deposits developed during the Jurassic, Cretaceous, and Eocene (Sinclair, 2007). The western Cordillera of Canada has several large porphyry deposits (e.g., Highland Valley, Galore Creek, Island Copper, and Gibraltar) (Figure 1.1). The majority of these deposits are associated with Mesozoic alkaline magmatism and are located in the Stikine and Quesnel terranes (Lowell and Guilbert, 1970; Cooke et al., 2005). There are a few, less well-known, occurrences of large copper porphyry deposits in other terranes of British Columbia (B.C.) and these porphyry deposits occur in close spatial association to the Coast Plutonic Complex (CPC); the largest of which is the Prosperity (formerly known as Fish Lake) Cu-Au porphyry deposit (Figures 1.1 and 1.2). Additional occurrences of hydrothermal alteration and mineralization occur within 25 km of the Prosperity Cu-Au porphyry deposit in rocks of a similar age and paleogeographic-tectonic setting. These occurrences lie in the Tchaikazan River area of the Taseko Lakes region and may represent a newly recognized tectono temporal suite of porphyry Cu deposits in B.C. One of the most fundamental problems in exploration for porphyry deposits is the ability to distinguish the few fertile igneous complexes from the many barren ones. The Tchaikazan River area may represent an area with a concentration of fertile igneous complexes, where the potential for new discoveries is high. 1.2 MAGMATIC-HYDROTHERMAL SYSTEMS IN THE SOUTHERN COAST MOUNTAINS, B.C. The Tchaikazan River area, located within the Coast Mountains of southwest British Columbia, hosts numerous, small, polymetallic mineral showings. Three of these, Hub, Charlie, and Northwest Copper, form the basis of this M.Sc. study. To date, the host rocks, 16 mineralization, and hydrothermal alteration of these showings are poorly documented. This study aims to fill the knowledge gap surrounding these spatially associated mineral occurrences. The Hub is a porphyry-style Cu-Mo showing hosted by a suite of -80 Ma intrusive rocks and is located at the base of the Tchaikazan River valley. Copper-molybdenite mineralization is hosted in quartz-sulphide stockwork veining and as a cement to a hydrothermal breccia. The Charlie showing is located to the north of the Hub, and comprises polymetallic quartz veins hosted within Cretaceous volcanic rocks. Professor H.V. Warren from the University of British Columbia discovered Au-bearing veins in the Charlie area during 1945 (Schau, 2006). The Northwest Copper area is the largest showing, in terms of surface extent, forming much of the northern part of the study area. The prospect comprises secondary Cu (malachite and azurite) together with chalcocite, native Cu-bearing quartz veins, and epidote-chalcopyrite-magnetite veins. This study integrates geological mapping, petrography, geochronology, thermochronology, a fluid inclusion study, and stable isotope studies to present a geological framework for understanding the development of the magmatic-hydrothermal system within the Tchaikazan River area and the larger Taseko Lakes area of southwest B.C. This project is one of two concurrent M.Sc. studies researching the links between Cretaceous igneous rocks and mineralization within the Taseko Lakes area, specifically focussing on the spatial and temporal evolution of epithermal and porphyry systems. These M.Sc. studies are financially supported by Galore Resources Inc. and Geoscience B.C. Galore Resources Inc. is a Vancouver-based mineral exploration company presently focused on exploration for copper and gold in British Columbia and Mexico. The company currently holds claim blocks hosting porphyry-style prospects, three of which (Hub, Charlie, and Northwest Copper) form the focus of this M. Sc. project. 1.3 RESEARCH GOALS The specific goal of this M.Sc. project is to characterize the spatial and temporal evolution of porphyry-style magmatism, mineralization, and hydrothermal alteration within the Tchaikazan valley. The thesis aimed to test the hypothesis that the mineral occurrences within the study area (Hub, Charlie, and Northwest Copper) may be linked by a single, large, magmatic-hydrothermal system. This goal was achieved by pursuing the following research strategies: - Characterize mineralogical alteration associated with magmatic-hydrothermal systems. The mineralogy of hydrothermal alteration is important in understanding the temperature and chemistry of these ore deposits. 17 - Determine the age of intrusion, alteration, and mineralization to see if the mineral showings occupy similar magmatic ages to each other, or to other known deposits in the Taseko Lakes area. - Understand the physiochemical evolution of the hydrothermal systems. - Define the tectonic and geological framework of hydrothermal activity. 1.4 RESEARCH APPROACH In order to fully answer these questions a combination of geological bedrock and alteration mineral mapping, core logging, sampling, and laboratory techniques were utilized. Analytical techniques employed include: (1) petrography and reflected light microscopy and the scanning electron microscope (SEM); (2) geochemical analysis; (3) geochronology, particularly 238U-06Pb and 40Ar-39; (4) X-Ray diffraction (XRD) and Shortwave Infrared (SWIR) spectrometry using an ASD Terraspec© portable spectrometer; (5) apatite and zircon thermochronology; (6) oxygen, hydrogen, and carbon stable isotope analysis; and (7) fluid inclusion studies. Geological mapping and core logging: Fieldwork was conducted over two field seasons, June- August 2006 and July-August 2007. The priority of the first phase of fieldwork was to collect geological data and representative samples of rock- and alteration-types. The second phase consisted of 1:1,000-scale bedrock mapping and builds upon mapping completed by Israel (2001). More detailed, 1:100-scale mapping was employed at the Hub porphyry deposit, where limited exposure created a need for increased detail of rocks exposed in historical trenches. Mapping was complemented by core logging of four diamond drill holes (approximately 1000 m) during the summer of 2008 working for Equity Exploration Consultants Ltd. Petrography: A total of 121 thin and polished sections were analyzed petrographically. Optical mineralogy techniques were utilized to characterize: (1) primary mineralogy; (2) alteration mineral assemblages; (3) hydrothermal veins and associated alteration haloes; and (4) the mineralogy and texture of ore minerals. Cathodoluminescence (CL) was used to aid with textural characterization of quartz veins. Shortwave infrared analysis: Short wave infrared (SWIR) analysis allows rapid identification of minerals that would otherwise only be identified as fine-grained clay. SWIR analysis was performed on hand samples using a TerraSpec® SWIR spectrometer from Analytical Spectral Devices Inc. to complement the detailed alteration and mineral mapping. The Terraspec is a 18 spectrometer that measures the infrared (1300-2500-nm wavelength) radiation reflected from geological samples. Light reacting with molecular bonds of a sample can cause a characteristic spectral response. It is from these characteristic absorption features that key minerals can be identified; in particular hydrous minerals (0H, H20, C032,NH4,A1OH, FeOH, and MgOH) that commonly form during hydrothermal alteration. A white reference standard has 100% reflectance across the whole spectrum is used to calibrate the calculations for the reflectance of the samples. Calibration was carried out approximately every 30 measurements taken. Multiple measurements were made in order to check for heterogeneities in the sample. The software programme TSG Professional 2007 aided interpretation of the collected spectra, which were then compared against reference spectra provided by another software programme SpecMin Pro software (SIT, 2002). Readers are referred to Clark et al. (1990) and Thompson et al. (1999) for more details on SWIR techniques and their application to geological materials. X-Ray diffraction: Ten powdered samples were analyzed using XRD techniques in a Siemens D5000 Diffractometer with a Vantech- 1 detector. Diffraction took place at 0.2° increments from 3 to 80° and was controlled using the XRD Commander Control software. Identification of clay minerals and other mineral phases was completed according to methods described in Brindley and Brown (1980). Geochronology: Four bulk samples of intrusive rocks were analyzed using U-Pb zircon techniques. Zircons were separated from their host rocks using conventional mineral separation methods. Approximately 25 of the coarsest, most inclusion-free grains were selected, mounted in an epoxy puck along with several grains of internationally accepted -1 1 OOMa FC- 1 standard zircon. The surface of the mount is washed with dilute nitric acid. Analyses are carried out using a New Wave 213 nm Nd-YAG laser coupled to a Thermo Finnigan Element2 high-resolution ICP-MS. Helium is used as the carrier gas. Data are reduced using the GLITTER software marketed by the GEMOC group at Macquarrie University in Sydney, Australia. Interpreted crystallization ages are based on weighted average of the calculated 206Pb/38Uages. Errors for the final interpreted age for each sample are given to the 2 sigma level using the method of Ludwig (2003). Mineral separates for 40Ar-39r analysis were hand-picked, washed in acetone, dried, wrapped in aluminum foil and stacked in an irradiation capsule with similar-aged samples and neutron flux monitors (Fish Canyon Tuff sanidine (FCs), 28.02 Ma (Renne et al., 1998). The samples were irradiated on January 4 through January 6, 2007 at the McMaster Nuclear Reactor 19 in Hamilton, Ontario, for 90 MWH, with a neutron flux of approximately 6x1 013 neutrons/cm2/s. Analyses (n=48) of 16 neutron flux monitor positions produced errors of <0.5% in the J value. The samples were analyzed on May 11 through May 16, 2007, at the Noble Gas Laboratory, Pacific Centre for Isotopic and Geochemical Research, University of British Columbia, Vancouver, BC, Canada. The mineral separates were step-heated at incrementally higher powers in the defocused beam of a lOW CO2 laser (New Wave Research MIR1 0) until fused. The gas evolved from each step was analyzed by a VG5400 mass spectrometer equipped with an ion- counting electron multiplier. All measurements were corrected for total system blank, mass spectrometer sensitivity, mass discrimination, radioactive decay during and subsequent to irradiation, as well as interfering Ar from atmospheric contamination and the irradiation of Ca, Cl and K (Isotope production ratios: (40Ar/39r)K = 0.0302 ± 0.00006,(37ArI9r)ca = 1416.4±0.5, (36Ar/9r)ca= 0.3952±0.0004, Ca/K = 1.83±0.01(37Arca/9rK).). Thermochronology: Bulk samples of intrusive lithologies were crushed and separated by ALS Chemex in Vancouver, B.C. Crushed samples were then sent to Ray Donelick at Apatite to Zircon, Inc. in Violi Idaho. Apatite and zircon mineral separates were dated using fission track methods. Detailed methodology is described by Reiners and Brandon (2006). SEM analysis: Ten carbon-coated thin sections were analyzed at 10 kV with beam current from 1 to 40 nA, using the Philips XL-30 Scanning Electron Microscope (with Princeton Gamma-Tech energy-dispersion X-ray spectrometer and image analysis systems) at the University of British Columbia, Department of Earth and Ocean Sciences. Fluid inclusion study: Microthermometric analyses of fluid inclusions from 5 doubly polished thin sections were performed to record the temperature of homogenization and determine the salinity of fluids. The Linkham THMSG 600 stage at the University of British Columbia, Department of Earth and Ocean Sciences was used to collect microthermometric measurements. Precision is ± 3.0°C for temperatures below 30°C and ± 0.2°C for temperatures above 3 0°C. 1.5 STUDY AREA The study area is located about 200 kilometres north of Vancouver (Figure 1.2) within the Taseko Lakes map area (Energy, Mines, and Resources Canada, map sheet 920/4) on the eastern margin of the Coast Plutonic Complex. The Ts’yl-os Provincial Park is located to the west within the Coast Mountains. Several large U-shaped valleys cut the area, the largest of 20 which is the north-south trending Taseko Lake Valley. The wide valleys and alpine terrain of the area show a transition from well-forested valley floors, to upper open alpine slopes. Elevations range from 1300 m to just under 3000 m, with the tree line located around 2000 m. The study area has a long history of mineral exploration and was granted high status for prospectability by the British Columbia Geological Survey (McLaren, 1990). The current M.Sc. study builds on Israel’s earlier study (Israel, 1999; Israel, 2001). Geological mapping, sample collection, and analysis were combined with the production of stratigraphic logs for selected parts of the Powell Creek Formation. Mapping reinforced much of the geological descriptions provided by Israel (2001), but highlighted some discrepancies and produced a different geological map. 1.6 PREVIOUS GEOLOGICAL RESEARCH AND MINERAL EXPLORATION Mineralization in the area is interpreted to be part of a magmatic-hydrothermal system with linked porphyry deposits that developed post-accretion in the late Cenozoic to Mesozoic (McMilIan et al., 1996). The geology of the Taseko Lakes area reflects a long history of deformation, alteration, and several episodes of mineralization related to Mesozoic and Cenozoic intrusions. Bateman (1914) first described the geology of the Taseko Lakes area. Comprehensive geological maps covering the Taseko Lakes area (920) were compiled by Tipper in 1963 and 1978, at scales of 1:253,440 and 1:250,000 respectively. McLaren (1990) further refined these maps to a scale of 1:100,000, forming part of a mineral assessment review of the Chilko Lake Planning Area. Detailed regional structural and tectonic studies formed the basis of a M.Sc. thesis by Israel (1999). Areas to the southeast of the Tehaikazan River area have been described in detail by Schiarizza et al. (1997), including a 1:100,000-scale map of the Taseko-Bridge River area (92J114, 15, 16; 920/1, 2, 3). In the Tchaikazan River area itself, McLaren (1990) conducted one of the most detailed geological surveys as part of a mineral assessment project by the British Columbia Geological Survey Branch. This was completed with a 1:100,000-scale map, which prior to the M. Sc. thesis by Israel (1999) represented the most detailed geological work within the Tchaikazan River area. Previous work on porphyry systems in the region includes brief summaries of the alteration associated with the systems, particularly in the Northwest Copper area (Bruce, 2000). Subsequent to this study there has been renewed interest in the exploration and development of the Taseko Lakes region. The interest is most likely related to the development of the Prosperity Cu-Au porphyry deposit. Prosperity is recognized as the largest bulk tonnage deposit ever 21 discovered in B.C., with an estimated mineable reserve of 960 million tonnes containing 4.4 billion pounds of Cu and 12 million ounces of Au. Despite these well publicized exploration projects there are still few, detailed deposit-scale studies available that integrate geological mapping, geochronology, geochemistry, and isotope studies. Therefore, one of the key aims of this M.Sc. is to characterize the spatial and temporal evolution of porphyry-style magmatism, mineralization, and hydrothermal alteration and place it within a geological framework. Regional Mineral Exploration Major porphyry deposits located close to the study area include Poison Mountain (M1NFILE 0920 046), Taseko (Empress) (MINFILE 0920 033), Prosperity (M1NFILE 0920 041), and Chita (MINFILE 0920 049) (Figure 1.2). The Prosperity porphyry Cu-Au deposit is located approximately 25 km north of the study area. It was originally staked in the 1930’s when it was known as the Fish Lake deposit (Heinrich, 1991). Hydrothermal alteration in the area can be striking and encompasses a range of both porphyry Cu and epithermal deposits (Schiarizza et al., 1997). Local Mineral Exploration The Tchaikazan River area contains areas of polymetallic mineralization and associated hydrothermal alteration. Three main areas (Hub, Charlie, and Northwest Copper) form the focus of this study (Plate I). Hub: The Hub showing is located proximal to the Tchaikazan River, with many of the surface outcrops lapped by the fast-flowing river (Plate I). Much of the area proximal to these outcrops is under vegetation cover and water-sodden, in places becoming bog-like. Exploration at Hub has therefore been limited to geological prospecting, trenching, and geochemical soil surveying. Presented herein is a summary of historical exploration at the Hub showing. Following the discovery of Au-Ag mineralization at the near-by Charlie showing, Cu and Mo mineralization were located along the banks of the Tchaikazan River in 1954. Falconbridge was the first mineral exploration company to show an interest in the Hub area in 1967; they carried out trenching, and drilled 6 diamond drill holes to the north of the Tchaikazan River in the area now known as the Hub showing. Between 1969 and 1973, Rio Tinto carried out a soil geochemistry program, testing for Cu and Mo anomalies, and drilled 434 m in 6 drill holes that intersected low values of Cu and Mo. In 1976, Zelon Chemicals acquired the mineral claims. During the period 1978 to 22 1982 Suncor took over the property and work was focused on producing geophysical data for the Hub showing, completing magnetometer, VLF electromagnetic, and induced polarization surveys. Suncor also drilled a total of 1,536 m in 8 drill holes, intersecting low Cu-Mo-Au-Ag values. Little work was carried out from the late 1980’s until the mid 1990’s. Between 1994 and 1999 the Jaguar Group (including International Jaguar and Pellaire Gold Mines) carried out a regional sampling program and airborne magnetic survey. Galore Resources Inc. acquired the property in 2005 and recently re-evaluated airborne geophysical data, as well as completing new magnetic and electromagnetic surveys. During summer of 2008 Equity Exploration Consultants Ltd. initiated a drilling program for Galore Resources Inc., completing 7 holes at the Hub showing. Significant intersections of copper were reported (Bartsch et al., 2009). Charlie: The Charlie showing is located on a steep mountain slope/ridge north of the Tchaikazan River, and is dominantly scree-covered. In 1945, Professor Harry Warren collected limited samples from the Charlie showing that were reported to contain native gold, silver, and gold tellurides hosted in quartz veins (Schau, 2006). Following up on these initial discoveries, limited soil sampling, a magnetometer survey, and a trenching program were completed during 1966, in addition to 8 drill holes totaling 1,250 m. In 1968 further trenching and a magnetometer survey were completed. The Charlie-Northwest Copper area is recognized as a highly prospective area of mesothermal precious metal/polymetallic vein and porphyry Cu-Mo (± Au) deposits. McLaren (1986) stated that the Charlie vein might be viewed as a precious metal epithermal vein system related to the predominantly volcanic lithologies and the large area of fracturing. Northwest Copper: The presence of the Charlie (Cu-Mo-Au) prospect to the south led to exploration in the surrounding area by International Jaguar in 1998 (Pezzot, 2005). Their work outlined a mineralized area of at least 8 km2 that is now identified as the Northwest Copper prospect. International Jaguar Equities implemented a diamond drilling program at Northwest Copper in 1999. Three drill holes were completed targeting surface Cu oxide showings, disseminated Cu, and porphyry style alteration (DDH 99-01: azimuth 008°; dip -45°; depth 267.4 m, DDH 99-02: azimuth 000°; dip -45° ; depth 257.Om, and DDH 99-03: azimuth 035°; dip -50°; depth 137.5 m). Several workers (Israel, 2001; Bruce, 2000; Blevings, 2008; Hollis et al., 2007) have studied the Northwest Copper area in terms of magmatic-hydrothermal alteration and mineralization. During the 2008 field season Equity Exploration Consultants Ltd. drilled a single 310.3 m deep diamond drill hole. The drill was oriented 110°/-60°, aiming to intersect the 23 interpreted acid leach cap (advanced argillic alteration) on the western flank of Ravioli Ridge and did not intersect any significant mineralization. The study area for this M. Sc. project is located within a wider area that contains abundant manifestations of magmatic-hydrothermal activity (Figure 1 .2B). These indicators to mineralization include small areas of secondary Cu and primary sulphide mineralization. The study area is host to three such prospective areas: Hub, Charlie, and Northwest Copper (Plate I). Several larger Cu and Au deposits occur relatively close to the study area, including: the Bralome Au mesothermal district, Chita Cu-Mo porphyry deposit, Poison Mountain Cu porphyry, and the Prosperity Cu-Au porphyry deposit. The Prosperity deposit occurs only 25 km north of the Tchaikazan River area and has the potential to become one of B.C. ‘s largest porphyry Cu-Au deposits (Figure 1.1). Several of these other examples of hydrothermal systems were part of the focus of an M.Sc. by Blevings (2008), who studied the Empress, Taylor-Windfall, and Pellaire deposits. The Empress deposit is southeast of the Tchaikazan River valley and is characterized by high- temperature (quartz-magnetite) alteration of the host intrusive rocks. Hydrothermal veining is common in the Empress deposit, and typically comprises quartz, gypsum, and Fe-oxides. The Taylor-Windfall Au-Ag epithermal deposit is located approximately 7 km east of the Tchaikazan River valley, near Battlement Creek and the Empress deposit, The deposit is vein- hosted and has been explored since the early 1900’s. It was the focus of an M.Sc. thesis by Price (1986) who characterized the mineralization and hydrothermal alteration. The Pellaire Au deposit represents another of these historical hydrothermal deposits; it too has been known about since the beginning of the century and has produced Au from five separate adits. Re-sampling and surveying of the property has occurred during the last few decades. 1.7 THESIS STRUCTURE This thesis is presented in traditional format with seven chapters. Chapter I (this chapter) is an introduction to the thesis. Chapter II provides an overview of porphyry magmatic hydrothermal systems and an introduction to issues relating to their genesis. Chapter III presents the geological and geochronological framework of the host rocks to mineralization. Chapter IV gives the palaeotectonic setting of the study area. Chapter V presents the physio-chemical manifestations of the magmatic-hydrothermal system and includes stable isotope and fluid inclusion data. Chapter VI provides the genesis and evolution of the magmatic-hydrothermal 24 systems in the study area. Chapter VII is an integrated geological history of the study area and thesis conclusions and implications. 25 USA Deposit Commodities Deposit Size • Cu-Au El Mo El Large • Cu I W-Mo 0 Medium • Cu-Mo El Ag Small El Au Kilometers — — — 0 200 500 Figure 1.1: Map of Canada showing the distribution of selected porphyry deposits, their metallogenic affinity and size (simplified from Sinclair, 2007). Km Figure 1.2: Map of British Columbia, with study area highlighting proximal magmatic-hydrothermal deposits. 0 250 500 OMI FOR INT CB INS = Omineca = Foreland = Intermontane = Coast = Insular Key deposit tve Highland Valley Copper Mountain O Alkaline porphyry • Calcalkaline porphyry • Past producer • Developed prospect 27 CHAPTER II REVIEW OF PORPHYRY MAGMATIC-HYDROTHERMAL SYSTEMS 2.1 INTRODUCTION A succinct definition of porphyry deposits is elusive, but has been defined as copper- bearing sulphides localized in a fracture network or stockwork and as disseminated grains in the rock matrix (Seedorf et a!., 2005). Resultant shallow (1-4 km) alteration and mineralization of host rock is genetically linked to magma emplaced at shallow levels in the Earth’s crust (6-8 km) (Beane and Titley, 1982). Associated magmas are typically intermediate to silicic in composition and related to magmatic arcs, above subduction zones (Berger et al., 2008; Seedorfet al., 2005). Porphyry systems are the most important primary source of Cu ore, and magmatic hydrothermal processes in these systems have been investigated in great detail (Halter et al., 2004). They are also sources of Au, Mo, Ag, and Sn, with significant byproducts being Re, W, In, Pt, Pd, and Se. These deposits typically contain large tonnages with low- to medium-grade of ore metals (Sinclair, 2007). Other deposit-types can be genetically related to porphyry deposits, including skams, high-sulphidation epithennal veins, and polymetallic veins (Berger et a!., 2008; Seedorf et al., 2005; Arribas et al., 2005). Sillitoe and Perelló (2005) described Fe-oxide-Cu-Au manto, Cu- bearing volcanogenic massive suiphide deposits, and Cu skarns spatially associated with porphyry Cu belts in the Andes. The relative lack of structural control and the size of porphyry deposits serves to distinguish them from these other types of ore deposits (Sinclair, 2007). 2.2 SIZE Porphyry deposits are large and can potentially contain up to several hundred million tonnes of ore; they range in size from tens of millions, to billions of tonnes (Sinclair, 2007). Grades of primary mineralization typically range up to 0.8% Cu and 0.02% Mo (Lowell and Guilbert, 1970). Gold contents range from approximately 0.004 to 0.35g/t (Sinclair, 2007). Most of the world’s discovered Cu, similar to other metals, is located in the few largest deposits (Singer et al., 2005) (Figure 2.1). 2.3 SPATIAL DISTRIBUTION Porphyry deposits occur in arc-related settings of various ages throughout the world. They are restricted to the Mesozoic to Cenozoic age orogenic belts in western North and South 28 America, around the western margin of the Pacific basin, and in the Tethyan orogenic belt in Eastern Europe and Southern Asia (Sinclair, 2007). Rarer are the arc-related deposits occurring within the Palaeozoic orogens of Central Asia, eastern North America, and Precambrian terranes. In Canada, porphyry deposits are clustered on the western margin of the Cordillera, within British Columbia, the Yukon and, to a lesser extent, the Northwest Territories. In contrast, the cratonic provinces of Alberta, Saskatchewan, and Manitoba are devoid of deposits. Farther east, deposits occur sporadically within Ontario, Quebec, and New Brunswick (Figure 1.1). 2.4 TEMPORAL DISTRIBUTION Many authors have investigated the timing and frequency of porphyry Cu deposits (Gustafson and Hunt, 1974; Meyer, 1972: Kesler and Wilkinson, 2006). The geological record shows porphyry Cu deposits ranging in age from Archaean to Recent, however most appear to be Jurassic or younger (Sinclair, 2007). Few porphyry Cu deposits have been identified that are older than 450 Ma (Cooke et al., 2005). In fact, very few porphyry deposits are known to be older than 200 Ma. Kelser and Wilkinson (2006) suggest that the temporal distribution of ore deposits is controlled largely by exhumation, burial, uplift, and erosion exposing subsurface material and suggested that erosional destruction the temporal pattern displayed by ore deposits. Ore deposits now observed at surface are presumed to have formed at depth, and only through the passage of geologic time and exhumation are they brought to the surface. The geologic record displays few young porphyry deposits. Their exhumation to the surface requires sufficient geologic time; many are still buried and therefore not visible at surface. The Jurassic, Cretaceous, and Eocene correspond to peak porphyry mineralizing periods in Canada (Sinclair, 2007). Authors have noted the pattern of most porphyry Cu deposits to form within the last 75 million years (with a modal of 12 m.y., with few forming older than 200 Ma) (Figures 2.1B and 2.2) (McMillan and Panteleyev, 1982; Cooke et al., 2005; Kesler and Wilkinson, 2006). Deformation and metamorphism of these older deposits may obscure primary features, making them difficult to recognize (McMillan and Panteleyev, 1982). The observed spatial trend of Cenozoic deposits is therefore likely to be a function of preservation, since the fundamental crustal-scale processes needed to form porphyry deposits have occurred throughout geological time. 29 2.5 GEOLOGICAL ATTRIBUTES 2.5.1 Geological setting and related magmatic rocks Porphyry Cu deposits are commonly associated with convergent plate boundaries and areas of andesitic volcanism (Sillitoe, 1973; Sillitoe and Bonham, 1984; Titley, 1982). Sillitoe (1988) noticed that crustal thickening associated with compressive tectonism was synchronous with the formation of giant porphyry Cu deposits. Most porphyry deposits form in subduction related continental and island-arc settings (Sillitoe, 1998; Gustafson and Hunt, 1975; Sinclair, 2007) (Figure 2.3). One of the defining characteristics of porphyry deposits is their genetic association with multiphase, porphyritic, granitic rocks, which are rich in sulphur, and oxidized (Berger et al., 2008). Intrusive rocks associated with porphyry Cu and porphyry Cu-Au deposits tend to be caic alkaline, predominantly hornblende- andlor biotite-bearing diorite to monzogranite (Richards, 2003; Sinclair, 2007; Seedorf et a!., 2005). Syenogranite, quartz monzonite, and quartz monzodiorite also occur in some porphyry deposits (Berger et al., 2008). 2.5.2 Morphology Singer et al. (2008) compiled data for the dimensions of selected porphyry Cu deposits worldwide. Porphyry Cu deposits are known to exist in many shapes; orebodies may be oval, spherical, lens-like, or cylindrical. Orebodies can measure several thousands of metres in three- dimensions. The length extent of a porphyry Cu deposit can be up to 4-5 kin, while the median size of hydrothermal alteration is 7-8 km2(Sinclair, 2007; Berger et al., 2008). The vertical extent of porphyry Cu deposits is somewhat dependent upon the lower Cu cutoff grade, which will vary with Cu prices and mining costs (Berger et a!., 2008). At Bingham, Utah, the vertical extent of mineable Cu approaches 1.4 km (Berger et a!., 2008). In terms of hydrothermal alteration, the vertical extent observed in porphyry deposits is variable depending largely on the size of the magmatic-hydrothermal system. At the Ann-Mason deposit, Yerington, Dilles (1992) suggests that greater than 30 km3 of the rock between 1 and 6 km depth is affected by hydrothermal alteration. Potassic alteration is observed to a depth of 6 km at the Ann-Mason deposit, indicating that the scale of hydrothermal alteration exhibited by these magmatic-hydrothenna! systems can be extremely large. 30 2.5.3 Structure Large-scale regional structures can be important to the distribution of porphyry deposits, e.g., the Rio Grande rift system is a locus for porphyry Mo deposits (Sinclair, 2007). Fault intersections and strongly fractured zones are thought to be particularly important in the development of these magmatic-hydrothermal systems (McMillan and Panteleyev, 1980). These large-scale structures create structural corridors ripe for the emplacement of upwelling magma and exsolved fluids. At the deposit scale, associated structures can result in a variety of mineralizing styles, including veins, stockwork, fractures, and breccia pipes (Sinclair, 2007). 2.5.4 Hydrothermal alteration Hydrothermal alteration in porphyry deposits is commonly mineralogically zoned (Lowell and Guilbert, 1970; McMillan and Panteleyev, 1982; Berger et al., 2008). Lowell and Guilbert’s description of the San Manuel-Kalamazoo ore body in Arizona and comprehensive review of 27 other porphyry deposits was a benchmark for porphyry research. The Lowell and Guilbert model consists of four alteration zones forming concentric shells (Figure 2.4A): orthoclase-biotite (potassic); quartz-sericite-pyrite (phyllic); illite-kaolinite-pyrite (argillic); and chiorite-epidote (propylitic). The concentric shells were thought to develop from the mixing of differently sourced fluids (Lowell and Guilbert, 1970; Berger et al., 2008). Central potassic alteration was thought to have formed from the up-flow of magmatic fluids. The thermally driven convection of surrounding meteoric waters leads to the distal development of the propylitic alteration zone. The Lowell and Guilbert model (1970) therefore formed a solid foundation upon which much of the subsequent decades porphyry research was built. The diorite model of Hollister et al. (1974) differs from the Lowell and Guilbert (1970) model. It focuses on quartz diorite to diorite intrusions from the Appalachian orogen instead of quartz monzonite to granodiorite intrusions. The alteration zoning of Hollister (1974) is poorly defined. In the potassic alteration zone, K-feldspar is not a prominent phase (as it is in the Lowell & Guilbert model); it may contain microcline in addition to, or in place of, orthoclase, and epidote may accompany chlorite. Phyllic alteration is considered to be poorly developed; instead a large propylitic, chlorite-rich assemblage is developed. Pyrite is not as extensively developed as an alteration mineral. Hollister attributes the differences between the models to the greater age and depth of erosion of the Appalachian orogen porphyry deposits (Hollister et al., 1974). Following the early work by Lowell and Guilbert (1970) and Hollister et al. (1974), a group of authors produced detailed deposit-scale studies, many expanding the simple model of concentrically zoned hydrothermal alteration (Dilles and Einaudi, 1992; Dilles et al., 2000; 31 Gustafson & Hunt, 1975; Proffett, 2003; Ulrich & Heinrich, 2001). The Lowell and Guilbert model lacks a context of timing of the alteration and overprinting relationships between alteration zones. Although it has proved useful in exploration and as a generalized framework for porphyry genesis, it does not, and was never intended to be applied to every porphyry Cu deposit. In many porphyry Cu deposits, alteration zones are complex, with phyllic alteration overprinting earlier alteration, rather than forming an intermediate zone, as it does in the Lowell and Guilbert model. This pattern of overprinting alteration suggests that there must instead be multiple pulses of fluid rather than a single fluid pulse of fluid flow (Rusk et al., 2008). Dilles (2000) and Dilles and Einaudi (1992) produced an integrated study on the Ann- Mason porphyry Cu deposit, Nevada (Figure 2.5). The integration of geologic and hydrothermal alteration mineral mapping, petrographic, and fluid inclusion studies produced a geological model for the origin and flow path of hydrothermal fluids through time and space. Post-ore tilting in the Late Tertiary rotated the Ann-Mason porphyry Cu deposit 90 degrees providing an unparalleled section through the vertical extent of a porphyry Cu deposit. Dilles and Einaudi (1992) identified several hydrothermal alteration assemblages including: (i) early potassic (phlogopite-K-feldspar); (ii) early sodic-calcic (actinolite-oligoclase); (iii) chlorite-albite; (iv) sericite-quartz; (v) alunite pyrophyllite; and (vi) diaspore-corundum-zunite. Dilles and Einaudi (1992) suggest at least 3 hydrothermal fluids of different origins were involved in the generation of the alteration and mineralization observed at Yerington. This was a diversion from the simplistic, earlier theories where a single fluid pulse created all hydrothermal alteration. Earliest porphyry events were accompanied by the interaction of two fluids: (1) a cooling, saline, hydrothermal fluid of magmatic origin linked to potassic alteration; and (2) a heating, saline fluid of non-magmatic origin linked to sodic-calcic alteration. These patterns are overprinted by a lower temperature, dilute, and convecting, non-magmatic hydrothermal fluids of surface water origin causing sodic and sericitic alteration (Dilles and Einaudi, 1992). The Dilles & Einaudi study illustrates the importance of a clear paragenesis of overprinting relationships and intrusions when considering the origin of hydrothermal alteration in a porphyry environment. Hydrothermal alteration may be described as pervasive, selective, or localized along veins (Dilles, 1987; Dilles and Einaudi, 1992). This spectrum of alteration imparts characteristic textures to the rocks that are associated with porphyry deposits, including complete destruction of igneous textures, intersecting stockwork veins, and partial replacement of primary igneous minerals with hydrothermal mineral assemblages. 32 2.5.5 Mineralization The principle hypogene Cu-bearing sulphide mineral in porphyry systems is chalcopyrite, although bornite, enargite, and chalcocite may occur (Berger et al., 2008). Other ore minerals include tennantite-tetrahedrite, molybdenite, enargite, magnetite, and hematite (Gustafson & Hunt, 1975). Pyrite is by far the most abundant sulphide mineral in porphyry Cu deposits. Copper ore mineral assemblages are a function of the chemical composition of the fluid phase and the pressure/temperature conditions of the fluid (Gustafson and Hunt, 1974; Berger et al., 2008). The most common ore-sulphide assemblage in unoxidized ores is chalcopyrite ± bornite, with pyrite and minor molybdenite. The pattern of hydrothermal alteration and sulphide mineralization can be complex because of overlapping effects from multiple intrusions (Gustafson and Hunt, 1975). This overprinting effect is observed within the El Salvador porphyry deposit. Gustafson and Hunt (1975) stated that much of the Cu was emplaced during an early stage hydrothermal event that followed early intrusions, which resulted in the central zone of K-silicate and chalcopyrite-bornite surrounded by realms of decreasing suiphides. However, Gustafson and Hunt (1975) recognized the intrusion of a later porphyry complex, which destroyed much of the early alteration and contributed minor chalcopyrite-pyrite and abundant molybdenite. This latter assemblage marks a transition in temperature regime and chemical character of the ore-forming fluid (Misra, 1999). As a result, the El Salvador study (Gustafson & Hunt, 1975) highlights the significance of multiple intrusions and fluid pulses in the porphyry realm. Zoning of sulphide mineralization in porphyry Cu deposits has been recognized and discussed by many authors (e.g., Lowell and Guilbert, 1970; Titley and Beane, 1982) (Figure 2.3B). Lowell and Guilbert (1970) noted a progressive gradation in the distribution of sulphides in almost all the deposits they studied. This sequence progressed from a core zone of dominantly disseminated sulphides, through veinlets and disseminations, to a peripheral zone dominated by veins and veinlets. Hypogene mineralization in porphyry deposits occurs in both the intrusions and wallrocks. 2.5.6 Fluid Evolution The predominant volatile in magmas in the Earth’s crust is H20; thus the principal volatile in magmas associated with a porphyry deposit is H2O (Burnham, 1997). Volatiles, such as, HCL, HF, H2S, SO2,H2, and C02, also play important roles during the separation of fluid from a crystallizing magma (Burnham, 1997). 33 It has generally been accepted that hydrothermal fluids in porphyry Cu deposits have two single-phase fluids: magmatic and meteoric. However, recent studies indicate that the single- phase fluid view may be simplistic (Einaudi and Dilles, 1992; Nonnan et al., 1991; Harris and Golding, 2002; Williams-Jones and Heinrich, 2005; Rusk and Reed, 2008). Fluid inclusion studies and supporting isotopic data can provide strong evidence for fluid pathways and sources. These techniques often illustrate that saline magmatic-hydrothermal fluids undergo a complex history of separation of volatile components into two fluids, a hypersaline liquid, and a vapor phase (Redmond et al., 2004). The theory of two single-phase fluid sources has prevailed, despite evidence that the dominant transport agent in several hydrothermal deposit types is a vapor (Williams-Jones and Heinrich, 2005). A vapor is a water-rich, salt-bearing fluid with a density below the critical density of the mixture of interest (Williams-Jones and Heinrich, 2005). Henley and McNabb (1978) published a paper suggesting that in the porphyry environment a plume of vapor is the transporting medium, not a single-phase fluid as previously suggested. Few researchers appeared to consider this option, with a few exceptions (i.e., Sillitoe, 1983), until Heinrich et al. (1992) reported vapor fluid inclusions in the Mole granite, Australia that contained far greater amounts of Cu than their liquid counterparts (Williams-Jones and Heinrich, 2005). Since then, other studies on porphyry Cu deposits have yielded high concentrations of Cu in the vapor phase. The advent of microanalytical techniques employing PIXE and laser ablation induced coupled plasma mass spectrometry (LA-ICPMS) led to an interest in investigating the role of vapor as a medium of metal transport in ore-forming systems. Rusk et al. (2004) illustrated that porphyry stockwork at Butte, Montana were caused by a single-phase fluid of low salinity (—4 wt. % NaCl) and intermediate density (—0.6 g cm3). Williams-Jones and Heinrich (2005) present a model for the fluid evolution regime in the porphyry environment (Figure 2.6). They suggested three fluid evolution regimes: (a) the fumerole stage; (b) the porphyry stage; and (c) the epithermal stage. As a result of cooling, each stage possesses different fluid evolution pathways. The three regimes may occur separately above magma chambers or develop sequentially during the evolution of a single, vertically extensive, porphyry to epithermal system. The exsolution of fluids under supralithostatic pressures at the cupola zone of magma chambers initiates hydrofracturing and the presence of a single-phase fluid of low to medium salinity (Williams-Jones and Heinrich, 2005). Above this, at pressures approaching lithostatic—vaporstatic, hypersaline liquid condenses from vapor. A single-phase fluid of low to intermediate density may exsolve and cool at pressures that are sufficient enough that it may never intersect the two-phase surface. The Butte Cu-Mo porphyry was likely formed from Cu-rich single-phase fluids of this type (Heinrich et al., 2004; 34 Rusk et al., 2008). Low to medium salinity sulphur-rich vapors deposit porphyry Cu-Au in presence of a volumetrically minor hypersaline liquid. Deeper, expanding, cooling, metal- depleted vapors are responsible for the advanced argillic zones, often distal to the porphyry environment (Williams-Jones and Heinrich, 2005). 2.5.7 Porphyry to epithermal continuum Spatial and temporal transitions/links exist within porphyry copper systems to advanced argillic and high suiphidation-state assemblages (Sillitoe, 1973; Gustafson and Hunt, 1975; Muntean et al., 2001). Recent studies, such as that at the Lepanto high-sulphidation Au-Cu and adjacent Far Southeast porphyry Cu-Au deposits have highlighted that such transitions do exist (Arribas et al., 1995). At least 15 examples of linked porphyry Cu deposits and epithermal deposits have been documented in the Andean Cordillera (e.g., Nevados de Famatina and La Mejicana, Argentina; Losada-Calderon and McPhail, 1996; Maricunga belt, Chile, Muntean and Einaudi, 2001; Agua Rica, Argentina, Landtwing et al., 2002) and southeastern Asia (e.g., Lepanton, Phillippines: Arribas et al., 1995). Geochronology from characteristic epithermal alunite and hydrothermal biotite and illite form the porphyry system and Lepanto and Far Southeast deposit indicate both epithermal and porphyry mineralization fromed from an evolving magmatic-hydrothermal system. This temporal relationship strengthens arguments for a genetic link between these two styles of ore deposit, and has implications for exploration (Arribas et al., 1995). Where on style of mineralization is found, there is potential for the other nearby. 35 I IHIuniNnniu0..10• Figure 2.1: A) Graph showing the world’s 25 largest porphyry deposits in terms of grade (Cu wt %) and tonnage (Mt) and B) Graph showing the ages of the 25 largest porphyry deposits in the world. (Simplified from Cooke et al., 2005) Sar Chesmeh 0 Grasberg Escondida • N. & C. Chile A S. & C. America USA/Mexico o Eurasia 0 SW Pacific A 1.4 1.2 1.0 0.8 () 0.6 0.4 0.2 0.0 0 2,500 5,000 7,500 10,000 12,500 Tonnage (Mt) Escondid Norte yu • Tolgoit1Bingham 0 • Rosario Pima Los Pelambres RayED La Granja 0 Butte A A • Cujaone Toki Kal’makyr / Aktogay Aiderly • Rio Blanco Teniente . • Chuquicamata Morenci-Metcalf A 0Lone Star •Rad ElCananeaomiro Tomic __________ C. Colorado (Panama) •N.&C.Chile 0 AS.&C.America 0 0 USA/Mexico Eurasia SW Pacific B 100 80 .60 M. Miocene - Pliocene 0 ci) C Cu C 0 0 Eocene - Oligocene 40 Palaeocene - eocene Palaeozoic 20 0 ci) Cu 0 C.) . E cDOI— •5 o 0 ) 9 CuD C Cu S .9 0) O ci) -. ‘.- — Cu - - Cr) 0 ° 9 0 Cu C ‘ 0 Cl) C o CD -J Cuci) C CuQ -J 0 I C.) E 2 9 0 •0 Cu Cu Cu F 9 Cu C Cl) Cu >Cl) C 0 E 0 • Cl) - • Cu C,) C 0)j (t,0 - 0 . 36 II _____ 15 10 5 200 160 120 80 40 0 Figure 2.2: Schematic relationships between emplacement depth (grey boxes), and age-frequency distributions (lower curves). A) Deposits emplaced at Earth’s surface should be most abundant at youngest age (1) and decrease in abundance steadily with increasing age (2, 3), B) Young deposits emplaced at depth should be largely absent from the surface (1) because time is required for them to be exhumed (2), after which they decrease in abundance (3), and C) Age-frequency distributions of porphyry copper deposits. From Kesler and Wilkinson, (2005). Increasing age Increasing age Porphyry Copper deposits n = 455 Bin size = 2 m.y. Modal Age = 12 m.y. 37 Figure 2.3: A) Cross section through a subduction zone and continental arc (Modified from Richards, 2003). B) Schematic cross section through a porphyry Cu-forming volcano plutonic system (From Richards, 2003). Asthenosphere crystalline basement Feeder dyke complex 38 Figure 2.4: Hypothesized vertical cross section through a model porphyry system: A) Zonation of hydrothermal mineral assemblages and; B) Distribution of sulfide minerals. Simplified from Lowell and Guilbert(1 970). Abbreviations- Ag: Silver, AIb: albite, Anh: Anhydrite, Biotite, Carb: Carbonate, Cp: Chalcopyrite, ChI: Epidote, Gal: Galena, K-feld: K-feldspar, Kao: Magnetite, Py: Pyrite, Qtz: Quartz, Ser: Sericite. Au: Gold, Bi: Chlorite, Epi: Kaolinite, Mag: Key to hydrothermal zoning D PROPYLITICChI - Epi - Carb -Aib Ii’ PHYLLIC LJ Qtz-Ser-Py ARGILLIC Qtz-Kao - chi D POTASSICQtz - K-feld - Bi -± ser ± anh fl Qtz - sericite -chlorite -Kfdspr ii 39 02 km 3 4 5 6 Figure 2.5: Map of the Ann-Mason porphyry copper deposit, Nevada. Hydrothermal alteration mineral zoning is shown, plus hypothesized fluid flow pathways. Late Cenozoic normal faulting has tilted a 3- by 5- km block containing the mid-Jurassic Ann-Mason porphyry copper deposit —90°and exposed the hydrothermal alteration pattern in cross section from 1- to 6-km paleodepth. Simplified from Dilles and Einaudi (1992) I Skarn (garnet - diopside) Sodic-Calcic (oligoclase - actinolite - sphene) Potassic (biotite ± K-feldspar) Weak biotite Fluid flow pathway Endoskarn (plagioclase - diopside) Weak Sodic-Calcic (epidote - sphene ± albite ± actinolite) Propylitic (albite - epidote - actinolite - chlorite - hematite) 40 Low-density, salt-free, HC1 SO2 ± H2S-rich vapor causes acid leached ‘vuggy’ quartz and advanced argillic alteration Generally barren Quiet degassing from internally convecting magma chamber ______ Deeper-sourced expanding vapor extends acid leaching and advanced argillic alteration; vapor is metal-depleted by cooling and deposition at greater depth. 4 Argillic ± sericite alteration Porphyry Cu ± Au deposition by low-medium salinity in presence of volumetrically minor hypersaline liquid; late within quartz veinlets in potassic zone Hypersaline liquid condensing from predominant vapor; quartz stockworrk veining and pervasive potassic alteration Supralithostatic pressure of exsolving fluid initiates hydrofracturing (single-phase fluid of low to medium salinity Low-salinity liquid derived from contracted magmatic vapor precipitates epthermal Au ± En ± Py by boiling, fluid mixing or fluid-desulfidation Acid neutralization by feldspar-destructive phyllic alteration, maintains Au concentration in low-salinity magmatic fluid Low-moderate salinity magmatic vapor contracts to aqueous liquid of same composition by cooling from >500°C to <350°C at pressures above critical curve; Cu-Fe precipitation Phase separation of buoyant H2S So2 Cu Au As-rich vapor from condensing hypersaline liquid rich in FeCI2. Potassic alteration ± deep porphyry Cu-Au mineralization Intermediate-density, medium salinity magmatic fluid separating as a single phase from hydrous magma Figure 2.6: Schematic cross-sections illustrating three potential fluid evolution regimes in magmatic-hydrothermal systems, which may occur separately above a magma chamber emplaced at different depths or develop sequentially during the evolution of a single, vertically extensive porphyry to epithermal system. From Ullrich and Heinrich (2006). Fumerole Stage Ii Legend I I Advanced argillic alteration I I Phyllic alteration Cu-Fe sulph ides I I Barren potassic (+ magnetite) I I Solidified porphyry ± propylitic alteration I I Partially molten magma Porphyry Stage u1\ Epithermal Stage 41 CHAPTER III GEOLOGICAL AND GEOCHRONOLOGICAL FRAMEWORK OF THE MAGMATIC-HYDROTHERMAL SYSTEMS IN THE TCHAIKAZAN RIVER AREA 3.0 REGIONAL GEOLOGIC SETTING The Tchaikazan River area of southwest B.C. is located near the eastern limit of the Coast Plutonic Complex, which forms the core of the longest mountain belt in the western Cordillera (Rusmore and Woodsworth, 1991). The batholith is thought to be a product of subduction of the Insular Superterrane along the continental margin of North America during the Jurassic-to-Eocene periods. British Columbia is composed of orogenic belts that are part of a larger geographic area known as the Canadian Cordillera. The Coast Belt forms the suture zone between the geomorphological belts of the Intermontane Belt (to the east) and the Insular Belt (to the west). In southern B.C., the Coast Belt is divided into the Southwest and Southeast Coast Belts. The Southwest Coast Belt (SWCB) consists of Mid-Jurassic to Mid-Cretaceous plutonic rocks and lesser Early Cretaceous volcanic rocks. The Southeast Coast Belt (SECB) comprises Mid- Jurassic to Mid-Cretaceous, dominantly elastic rocks of the Tyaughton-Methow basin, including the Relay Mountain, Jackass Mountain, and the Taylor Creek Groups. The Jackass Mountain Group overlies rocks of the Cadwallader terrane to the north and the Relay Mountain and Taylor Creek Goups overlie the Bridge River terrane to the south (Israel et al., 2006). This M.Sc. study area includes Early Cretaceous arc rocks and elastic rocks consisting of mainly small volcanic arcs and overlap assemblages that were amalgamated during the Mid Cretaceous (Figures 3.1 and 3.2) (McLaren, 1990; Schiarizza et aL, 1997; Monger et al., 1994; Tipper, 1969 and 1978; Israel, 2001). The SECB is host to numerous prospective and past- producing deposits, including the Bralorne Mining District and Prosperity Cu-Au deposit. Israel et al. (2006) stated that folded panels of rock separated by thrust faults or steeply dipping strike-slip faults characterize the study area. Three phases of deformation are recognized within the Tchaikazan River area: (a) Dl, north- to north-east-directed, large-scale thrust/reverse faulting and fault-related folding; (b) D2, regional and local sinistral faulting; and (c) D3, dextral strike-slip faulting. The Tchaikazan Fault is the largest structure in the study area and cross-cuts all other features. It is believed to have formed during the D3 event, the latest Cretaceous to Eocene dextral strike-slip event that affected the entire SECB (McLaren, 1990; Schiarizza et al., 1997). The sense and amount of displacement on the Tchaikazan Fault have not yet been 42 determined for the study area. However, the northwestern part of the fault yields apparent dextral offset of 7 to 8 km (Mustard and van der Heyden, 1997). The deformation inferred by Israel et al. (2006) is somewhat earlier than the deformation recorded by similar faults in the area, such as the Chita Creek and Fortress Ridge Faults. These faults are components of the Yakalom Fault system, which was active during Early to Middle Eocene time (Figure 3.1A). The Tchaikazan Fault is interpreted to have been the locus for 40 to 50 km of sinistral displacement, prior to its reactivation as an Eocene dextral strike-slip fault (Israel et al., 2006). Most lineaments observed in the Tchaikazan River area are interpreted as relating to the Cretaceous to Eocene dextral strike-slip D3 event that affected the whole of the SECB (McLaren, 1990; Schiarizza et al., 1997). They may represent splays off larger faults formed during the youngest D3 event. Numerous smaller structures that cross-cut all other structures are related to these larger structures (Israel et a!., 2006). Evidence for hydrothermal activity and mineralization is widespread throughout the SECB, highlighted by the numerous small metallic showings, developed prospects, and altered host rocks. All previously reported mineralization in the SECB is hydrothermal in origin, and covers the spectrum of porphyry, epithermal, and mesothermal mineralization (Bruce, 2000; Israel, 2001; Blevings, 2008). Israel (2001) concluded that the Taseko Lakes area represents the transition between the Gambier arc and the Tyaughton basin, and suggested that the uplift of Early Cretaceous rocks provided a source for the upper Tyaughton basin (Figure 3.2). By Mid-Cretaceous time contractional deformation (Dl) was dominant. Sinistral, strike-slip, and contractional fault movements occurred in the area from the Mid-Cretaceous to the Tertiary (D2) (Schiarizza et al., 1997; Israel et a!., 2006; Journeay and Friedman, 1993). During the Late Paleocene to Eocene periods contractional movement was superseded by dominantly dextral strike-slip movement (D3), forming large-scale faults (e.g., Tchaikazan and Yakalom Faults) (Figures 3.1 and 3.2). 3.1 LOCAL GEOLOGICAL SETTING — FIELD OBSERVATIONS The study area comprises faulted, Cretaceous to Eocene sedimentary, volcanic, and associated intrusive rocks (Figure 3.1). The faulting, similarity of rock-types, and lack of marker horizons, creates an intricate geology that has been reviewed many times (Tipper, 1963; Woodsworth and Tipper, 1978). Regional-scale geological maps have been produced by McLaren (1990), Schiarrizza (1999), Israel (2001), and Israel et al. (2006) (Figure 3.1). The two main stratigraphic units recognized in the study area are the Early Cretaceous volcano-sedimentary Tchaikazan River Formation and the Late Cretaceous Powell Creek 43 Formation (McLaren, 1990; Israel, 2001). These units are the host to several polymetallic showings, including the Hub, Charlie, and Northwest Copper prospects (Plate I). Dividing the area is a large east-west striking thrust sheet that places rocks of the Tchaikazan River Formation above rocks of the Powell Creek Formation (Figure 3.3). 3.1.1 Tchaikazan River Formation The formation was named by Israel (2001) and previously mapped as the Taylor Creek Group by McLaren (1990). Israel (2001) stated that fossil evidence suggests an age as old as 140 Ma (Berriasian). The Mt. Pilkington intrusion cross-cuts the formation and yields a U/Pb zircon age of 102 ± 2 Ma (Israel, 2001), giving a minimal depositional age. The Mt. McLeod batholith cuts the formation to the southwest of the study area and provides a minimal depositional age of 103.8 ± 0.5 Ma (Israel et al., 2006). The Tchaikazan River Formation is here, based on field mapping by the author, split into three facies associations: (i) a sedimentary-dominated facies; (ii) volcano-sedimentary facies; and (iii) a volcanic-dominated facies (Figure 3.3; Plate I). These divisions are an extension of the two-fold facies division presented by Irasel (2001). The sedimentary-dominated facies includes rocks in the southwest of the study area that Israel previously attributed to the Falls Creek Formation. These rocks are reinterpreted here as part of the Tchaikazan River Formation. Volcanic facies: The volcanic facies is estimated to be at least 1000 m thick and is characterized by an intercalation of sedimentary and subaqueous to subaerial volcanic rocks and andesite/basalt flow units (Israel, 2001). Massive, coherent andesite to basalt/andesite flows dominate the upper parts of the volcanic facies. They are often variably phenocryst-rich, with homblende or plagioclase phenocrysts, hornblende usually being the more abundant. Brecciated volcanic units are common lower in the statigraphy, but are less abundant than in the Powell Creek Formation observed to the west (see below). Both breccia clasts and matrix material are generally andesitic, with only subtle differences in textures (aphanitic versus vesicular). Clast shape is highly variable ranging from subangular to subrounded. Preferential weathering of the matrix material compared to the clasts is observed. Columnar jointed volcanic breccias were observed in the southwest of the study area. Volcano-sedimentary fades: Rocks of the volcano-sedimentary facies of the Tchaikazan River Formation are widespread in the southeast and eastern parts of the field area, forming much of the Charlie-Northwest Copper area. It is characterized by packages of fine- to medium-grained 44 elastic rocks and minor, coherent, andesite flows. Intercalated sandstone, siltstone, and mudstone occur within the facies. Grain size, bed thickness, structure, and rock-type are highly variable throughout the facies. Sandstones are generally lithic arkose to feldspathic wacke, grading into siltstones. Clast and grain shapes are generally subrounded and moderately sorted. Mudstone units are characterized by their fine matrix and dark grey-green colour. Bedding is either massive or weakly parallel laminated; no cross-bedding or other palaeocurrent indicators were observed. Mudstone units tend to overly coarser units and indicate a crude fining upwards environment of deposition. Relatively small (<15 m thick), lobe-like, syn-sedimentary intrusions are also present in the upper sections of the Tchaikazan River Formation. They are typically porphyritic, feldspar-rich, and cross-cut fine-grained, black mudstones. Fragmentation and peperitic margins are observed at intrusive contacts. These peperites were common at high elevations towards the eastern limits of the mapped area (Figure 3.5). Contact zones are generally irregular, undulating, and comprise clasts of the host sediment mingled and dispersed through the intruding lithology. Israel et al. (2006) inferred that the sedimentary facies occurs below the volcanic facies and geological mapping from this study supports this conclusion. Israel (2001) placed sedimentary-dominated outcrops within the Falls Creek Formation. Here we suggest that these rocks are instead a facies variation of the Tchaikazan River Formation and do not separate these rocks into the Falls Creek Formation. Israel (2001) suggested that the sedimentary rocks of the Tchaikazan River Formation are at least 136 Ma, maybe even as old as 146 Ma. This study confirms an age greater than 80 Ma (see section 3.4). Sedimentary fades: Israel et al. (2001) estimated a thickness of up to 500 m for the sedimentary facies, based upon an estimate from the ‘type’ section at the Twin Creeks area. Sedimentary rocks including fme-grained mudstones, siltstones, sandstones, and pebble conglomerates are observed. The sedimentary package is bounded to the northwest by the Northwest Copper thrust fault. The sedimentary packages dip moderately, with dip directions ranging from southeast to southwest. The sedimentary rocks are intercalated with rare volcaniclastic rocks and coherent volcanic flow units, typically less than 1 m thick. Upper parts of the sedimentary facies show many characteristics of the Bouma turbidite sequences. Complete sequences (A-E) are uncommon within the area, but, partial Bouma sequences are observed and interpreted to be part of deposits formed by turbidity currents and sandy debris flows. Structures such as graded-bedding, laminations, bioturbation, rip-up clasts, and load and flame structures were observed within the sequences of sedimentary rocks (Figures 3.5C and D). Israel (2001) chose to separate this area of dominantly sedimentary rocks and place 45 it into the younger Falls River Formation. Israel (2001) stated that the Falls River Formation and the Tchaikazan River Formation could be distinguished by the relative greater abundance of fine grained marine sedimentary units observed in the Falls River Formation. 3.1.2 Powell Creek Formation The Powell Creek Formation is an extensive package of rocks covering most of the Northwest Copper area to the south of the Tchaikazan fault (Figure 3.3). The formation comprises greater than 2 km thickness of volcanic lithologies and can be crudely divided into the coherent and non-massive facies. The coherent facies is comprised of massive, coherent, dominantly andesitic volcanic flows. In contrast, fragmental volcanic breccias, matrix-supported breccias, and volcaniclastic sandstones characterize the non-massive facies. Coherent facies: The coherent facies of the Powell Creek Formation is dominantly andesitic, with rare basalts. Coherent volcanic flows dominate the Northwest Copper area, particularly along the northern part of Ravioli Ridge (Figure 3.3). The andesites are variable in colour and texture; however they are typically plagioclase-phyric with plagioclase phenocryst size ranging from 1 to 5 mm and phenocryst content ranging from 5 to 10%. Apparently aphyric textured lava flows were also locally evident. Non-massive facies: The non-massive facies of the Powell Creek Formation lacks significant thicknesses of coherent andesite flows. Instead, bedded volcaniclastic sediments, volcanic breccias, debris flows, and pyroclastic deposits are common. Andesite flows are volumetrically minor in the non-massive facies and rarely reach thicknesses greater than a few metres. Concentrations of brittle fractures oriented perpendicular to the upper contacts of lava flows were observed. Volcaniclastic (resedimented) sandstones are relatively common in the non-massive facies of the Powell Creek Formation (Figure 3 .6E). The sandstone units are typically bedded and dip moderately to steeply to the southwest. Individual grains are generally subrounded to subangular in shape. The sandstones are typically crystal-rich with coarse feldspar crystals, volcanic lithic clasts, and mudstone intraclasts. Crystal-rich, volcanogenic sedimentary deposits are dominant in the stratigraphic log produced for part of the Powell Creek Formation (Plate I; Figure 3.7). These deposits are likely derived by erosion of volcanic units that were significantly reworked prior to final deposition. 46 Volcanic breccias account for greater than half of the observed volcanic facies in the Northwest Copper area. Breccias composed of andesite clasts and andesite matrix are relatively common .in the non-massive facies. Breccia clasts do not appear to represent any source outside the formation. These breccias are interpreted as flow front breccias or brecciated tops of lava flows. Clasts are poorly sorted and subangular in form, with irregular grain boundaries. Well- bedded volcanic sandstones are typically poorly cemented. Where matrix material is rare, crystal concentrations are high. Clasts of maroon-coloured, aphanitic andesite are commonly observed in the sandstones. These clasts range in size from a few mm to 40 mm in diameter. Plagioclase phenocrysts are common in the resedimented volcanic sandstone units. Way-up structures are locally evident (Figure 3.7), but fining of volcaniclastic units appears to be the most useful tool for the determination of stratigraphic top for the resedimented units. Pinching and swelling of the units is widespread throughout the formation. Volcaniclastic aggregates, containing particles and crystals from pre-existing andesite units are regularly observed in the Northwest Copper area. Texturally variable brecciated units are commonly observed in the non-massive facies. Rounded to sub-rounded andesite clasts are common in the breccias with clast typically several centimeters in diameter, although clast size is variable. Breccias are typically matrix-supported, with fine-medium sized lithic components forming the matrix. Differential weathering of the matrix material to clasts is commonly observed, causing clasts to protrude from the matrix that contains them (Plate I; Figures 3.6A and B). Poorly sorted, volcaniclastic breccias are frequently observed in the study area. They are typically matrix-supported, although locally clast-supported fabrics are developed. Particle/clast size ranges from clay- to boulder-sized particles. Andesite is the dominant clast composition observed in the Northwest Copper area. Contacts between debris flows are generally sharp. The textures exhibited are similar to those inferred for block and ash type deposits. Clast size, composition, and sorting are highly variable in the Powell Creek Formation. Large, decimeter-scale blocks of coherent lava flow were ‘rafled’ on top of debris flow units (Figure 3 .6C). Blanketing of fine-grained pyroclastic material atop coherent andesite lava flow units was observed in the northern part of the study area (Figures 3.6D and E). The Powell Creek Formation has been well studied in areas to the northeast and east of the Tchaikazan River area. To the northeast, the formation is intruded by the 92.4 ± 0.3 Ma Dickson-McClure batholith (Parrish, 1992; Schiarizza et al., 1997) and relationships that suggest the base must be Turonian (93.5 ± 0.8 Ma and 89.3 ± 1 Ma) in age (Israel et al., 2006). McLaren (1990) used 40Ar-39r dating on hornblende and provided ages for the base of the formation of 94.6 ± 6.6 Ma, 95.9 Ma to 78.95 ± 4.1 Ma from the highest levels in the stratigraphy (Maxson, 47 1996). Schiarizza et al. (1997) inferred the formation to be at least 93.5 ± 0.8 to 89.3 ± 1 Ma in age. Interpretation In ancient volcanic sequences, establishing a primary origin for poorly sorted, ungraded, monomict mass-flow deposits lacking evidence of hot emplacement can be difficult (McPhie et al., 1993). Hence, the similar internal textures of much of the breccias observed at Northwest Copper can be assigned to either a volcaniclastic debris flow or primary block and ash deposit origin. Transport of volcaniclastic particles from the site of initial fragmentation may be continuous with a primary volcanic clast-forming process (auto-brecciation), or involve surface sedimentary transporting agents, such as water. The open framework character, the sandy-matrix, and the massive nature of much of the volcaniclastic deposits of the Powell Creek Formation are consistent with debris flow and lahar events (Cas and Wright, 1998), where the dominant transport agent was likely debris flows, debris avalanches, and fluvial subaqueous currents. Bedforms in these deposits indicate rapid (commonly mass-flow) deposition (McPhie et al., 1993). The dominance of volcaniclastic and resedimented volcanic deposits in the Powell Creek Formation indicates an active and variable environment of deposition, likely involving transport in mass-flow, traction, and suspension. The Powell Creek Formation includes a variety of volcanic deposits. These include primary deposits, resedimented volcaniclastic, and volcanogenic sedimentary deposits (Table 3.1). Schiarizzia et al. (1997) interpreted the deposition of the formation through processes of non-marine volcanic and volcaniclastic conditions. This is consistent with the data presented here, inferring that non-marine sedimentation developed as a result of the erosion of uplifted orogens. Uplift of the Coast Mountains led to the westward erosion of volcanic island arc clastic sediments and deposition of the Powell Creek Formation during the Late Cretaceous (Rusmore and Woodsworth, 1991). 3.1.3 Intrusive rocks The study area is host to abundant and widespread intrusive rocks, ranging from dykes to larger plutonic bodies (Figure 3.3). The largest of these bodies is located within the Tchaikazan River valley and is informally known as the Hub diorite/granodiorite (Hollis et a!., 2009). It is this diorite/granodiorite that hosts much of the porphyry-style mineralization observed at the Hub deposit. 48 Hub Intrusive Complex A suite of several igneous rocks characterizes the Hub porphyry deposit; however outcrops are dominated by a diorite/granodiorite (Figure 3.8, Plate I). The Hub diorite/granodiorite is volumetrically the most extensive igneous rock, accounting for greater than 60% of the Hub porphyry deposit. The Hub diorite is a coarsely crystalline, massive, porphyritic diorite. It is composed of plagioclase (—50%), biotite (10-25%), and hornblende (25%) phenocrysts in an aphanitic, plagioclase-dominated groundmass. Plagioclase phenocrysts are well formed and are oscillatory-zoned. The full to partial replacement of plagioclase by sericite is common. Biotite and homblende phenocrysts are generally pseudomorphed by aggregates of chlorite (Figure 3.9). The Hub intrusion shows variability from the diorite composition: granodiorite is also observed, but is relatively minor when compared to the diorite phase. Geochronology(40Ar-39r and 238U-06Pb -zircon) constrained the age of the Hub diorite to approximately 80 Ma (see section 3.4). A sample of the Hub diorite was collected for analysis by ZFT and AFT analysis yielded ages of —76 Ma and 31 Ma respectively (see section 3.5). Feldspar porphyry dykes considered to be part of this intrusive centre were also sampled from the Charlie area, where they cross-cut the Early Cretaceous rocks of the Tchaikazan River Formation. These yielded ages of 79.9 ± 1.1 Ma (GO-i) and 76.6 ± 0.7 Ma (GO-2) (see section 3.4). A 5 rn-wide, unmineralized feldspar-hornblende porphyry dyke cross-cuts the Hub diorite and contains up to 7% pyrite (Figure 3.8). Feldspar is typically completely altered to sericite and mafic minerals altered to chlorite, epidote, and magnetite. This single feldspar-homblende dyke yielded a U-Pb age of —70 Ma (see section 3.4). An unmineralized plug of equigranular monzonite cross-cuts the Hub diorite and is inferred to post-date the main phase of mineralization and hydrothermal alteration. Limited drill hole data provided a cross-section through part of the Hub intrusive complex (Figure 3.10). Hydrothermal alteration commonly obscured geological contacts between intrusive bodies and drill hole spacing limits the correlation of intersections in between drill holes. A series of diorite/granodiorite intrusive bodies are the most geologically feasible model for subsurface intrusions, with later feldspar-hornblende dykes cross-cutting the main diorite/granodiorite stock. Northwest Copper Intrusive Complex The youngest known intrusion in the study area is the Northwest Copper pluton, which is exposed in a small plug (Plate I, Figure 3.11). The pluton is located within a small hanging glacial cirque; outcrops are observed in both the northern and southern walls and inferred to be 49 the same intrusion. It is felsic in composition, containing approximately 40% quartz, 30% plagioclase, and 30% mafic minerals and opaques, including biotite and hornblende (Figures 3.11 B and D). Chlorite aggregates pseudomorph phenocrysts of homblende. The intrusion is complex with several compositional variations (Figure 3.11 B), which include changes in the proportions of hornblende and feldspar. Numerous round xenoliths of the Powell Creek Formation are included within the intrusion (Figure 3.11 C). Several aplite dykes cross-cut the main intrusive body and comprise over 80% alkali feldspar and quartz. The Northwest Copper pluton yielded a U-Pb zircon age of 57.33 ± 0.85 Ma (see section 3.4). Several hornblende-phyric diorite dykes are located proximal to the Northwest Copper pluton and are inferred to be part of the same magmatic pulse. They are sub-vertically oriented, trend northwest-southeast, and are typically about 5 m thick (Figure 3.11A). The dykes are relatively unaltered and most homblende is relatively fresh. One of these dykes, proximal to the Northwest Copper pluton, gave a 40Ar-39r hornblende cooling age of 60.01 ± 0.46 Ma (see section 3.4). It is not known whether these dykes cross-cut the Northwest Copper pluton. Other Intrusive Rocks Other smaller bodies of intrusive rocks are common throughout the study area; these cannot be directly correlated to the larger Northwest Copper pluton or the Hub diorite, but are inferred to be part of the larger magmatic-hydrothermal system within the Tchaikazan River area. A small plug of syenite occurs within the north part of Ravioli Ridge (Figures 3.2 and 3.12A). Small syenite dykes appear to cross-cut a larger felsic intrusive rock (Figure 3.12B). It is equigranular and comprises over 60% anhedral feldspar crystals, 30% quartz, and 10% hornblende (Figure 3. 12C and D). Feldspar is typically altered to sericite. Primary twinning remains in some of the least-altered plagioclase crystals. Epidote replaces feldspar and accounts for 5% of the syenite. Finely disseminated magnetite replaces, and is associated with, Fe-rich chlorite. Throughout the study area numerous feldspar-hornblende dykes of unknown age cross cut the Cretaceous volcanic rocks (Figures 3.3 and 3.13). These dykes could be related to the nearby Tchaikazan Rapids pluton (60 Ma) north of the Tchaikazan fault. These dykes are commonly intensely chloritized and sericite replaces plagioclase feldspars. Intensely altered dyke margins are typically pervasively weathered extending several centimetres into the surrounding, usually volcanic host rock. Millimetre-scale calcite veining is typically concentrated at these dyke margins. 50 Subsurface Intrusive Rocks To complement regional mapping and geochemistry, Galore Resources Inc. conducted an aeromagnetic survey of the Taskeo Lakes area. Several subsurface intrusive bodies are inferred to be present in the study area based on the presence of aeromagnetic anomalies (Figure 3.15). S.J.V. Consultants collected the aeromagnetic survey during the summer of 2005 and the data was reanalyzed by Klein (2008). Magnetic highs correspond well to known intrusive bodies, even though they occur within volcanic rocks that typically also produce a highly magnetic signature. Other magnetic highs are interpreted to represent subsurface intrusions, potentially of a similar age to the Hub or Northwest Copper intrusive rocks (Figure 3.15). Much of the survey area is underlain by relatively low magnetic responses that fall within a 500nT range between 55,000 and 55,500nT (Pezzot, 2006). However, the magnetic response around the Hub showing displays a significant increase in magnetic amplitude (>56,000 nTs). Changes in magnetic data to the northwest of the Hub showing reflect changes in lithology or facies change in the regional geology. Several northwesterly trending magnetic lineations dominate and likely represent faults. Magnetic data for the Northwest Copper area shows several areas of higher magnetic response (Figure 3.15) that generally correspond to known or inferred intrusive bodies. In particular, a strong magnetic gradient was observed for the Ravioli Ridge area, where a 4 km2 magnetic anomaly is centered. Several smaller magnetic highs are located to the southwest of this main magnetic feature. One of these smaller anomalies located in the southwest of the mapped area is beneath a small outcrop of the Northwest Copper pluton. The Northwest Copper pluton is therefore inferred to be larger than its surface exposure would suggest. Localized high magnetic responses to the north of the Hub anomaly correspond well to areas mapped as thick, coherent lava flow units of the Tchaikazan River Formation. 3.2 REGIONAL METAMORPHISM The rocks of the Tchaikazan River area exhibit a mineral assemblage that could be attributed to a local hydrothermal phenomenon, but could easily be assigned to a regional metamorphic signature. Chlorite, epidote, albite, calcite, and quartz are variably developed in the volcanic rocks of the Tchaikazan River and Powell Creek Formations. This mineral assemblage varies in intensity from selectively developed to pervasive. Prograde metamorphism of mafic and intermediate volcanic rocks is characterized by the growth of hydrous mineral phases replacing primary igneous phases. However, propylitic assemblages of porphyry systems are themselves hydrous mineral phases. Smith (2005) 51 describes metamorphic alteration mineral assemblages of quartz-albite-chlorite-epidote-carbonate ± prehnite ± pumpellyite ± actinolite. Therefore, difficulty arises whilst attempting to assign these mineral assemblages to either processes of regional metamorphism or porphyry-related hydrothermal alteration (Cas and Wright, 1998; Wilson et al., 2003; Cannell et al., 2005). For example, work describing the regional metamorphism of the Ordovician volcanic sequences in the Cadia district based upon the distribution of secondary mineral assemblages (Smith, 1969) appears very similar to hydrothermal alteration described by Wilson et a!. (2003). McLaren (1990) stated that most rocks attributed to the Taseko-Bridge River area are unmetamorphosed or are affected by very low metamorphic grade; higher metamorphic grade rocks occur locally near some of the large Cretaceous-Tertiary plutonic rocks. Commonly observed metamorphic minerals include chlorite, epidote, prehnite, calcite, albite, and quartz (McLaren, 1990). In this study, chlorite-epidote-prehnite-calcite-albite is observed throughout much of the volcanic rocks of the Tchaikazan River area, and it is this assemblage that cannot be discriminated with any confidence from weak background regional metamorphism. Therefore, the widespread chiorite-epidote-albite-carbonate mineral assemblage, so ubiquitous in the volcanic rocks within the study area, cannot be directly related to the porphyry system, and could represent a regional metamorphic hydration event. Large hydrothermal systems may have develop along the margins of the large mass of the Coast Plutonic Complex, creating this (intense to weak) epidote-carbonate (± chlorite ± albite) alteration. However, the development of zones of intense epidote alteration and veining in the Tchaikazan River area can be distinguished from any background regional metamorphic hydration event. These areas of intense epidote alteration (see Chapter V) are typically located proximal to plutonic bodies or large-scale faults. It is difficult to conceive how isochemical (regional) metamorphism could produce the spatial distribution of the degree of alteration, and hence such transformations require intensive metasomatism, which is most readily achieved by hot, hydrothermal fluid. 3.3 STRUCTURAL GEOLOGY OF THE FIELD AREA 3.3.1 Large thrust faults The study area is divided by three large thrust faults: Ravioli, Linguine, and Tagliatelle (Figure 3.3). These faults dissect the stratigraphy and form ramp and flat geometries. Rocks attributed to the Powell Creek Formation form the flats, with rocks of the Tchaikazan River Formation forming the ramps (Figure 3.14). A large, northerly dipping normal fault cuts the Ravioli fault (Figures 3.3 and 3.14). Bedding of the Tchaikazan River Formation sedimentary 52 and volcano-sedimentary facies, as well as resedimented units of the Powell Creek Formation, generally dip steeply to the south-southwest (Figure 3.3). Several large intrusive bodies are intruded into this thrusted stratigraphic package (Figure 3.3). A large scale contractional, north verging thrust fault (Ravioli fault) placing andesite rocks of the Early Cretaceous Tchaikazan River Formation atop the younger Powell Creek Formation (Figures 3.3, 3.14 and 3.16). The faults dip moderately to steeply to the southwest and generally strike east-west (Figure 3.16). The Ravioli thrust fault at Northwest Copper has a mylonite fabric defined by fine-grained aggregates of mica and chlorite. Similar mylonite rocks are observed to the west, again in the vicinity of the Linguine thrust fault (Figure 3.17), similar to that reported by Blevings (2008). The fault zone is interpreted to have created permeable pathways for the ingress of fluids in the fault zone. Phyllosilicate minerals, such as mica and chlorite, replace plagioclase and hornblende. Intense illite alteration was observed in proximity to the Ravioli thrust fault to the north of the study area, where Avalanche Creek, marks the thrusted contact between the Tchaikazan River Formation and Powell Creek Formation (Figure 3.18). Blevings (2008) observed a mylonite along the Ravioli thrust with a foliation defmed by quartz-feldspar ribbons and chlorite. An illite sample taken from the Ravioli thrust zone (to the south), interpreted to represent the age of thrust fault movement, reported by produced a40Ar-39r plateau age of 60.53 ± 0.33 Ma (Blevings, 2008). The mylonite foliation is defined in the sample by quartz-feldspar ribbons, chlorite with anomalous blue interference colours, and fine-grained Fe-oxides. The protolith for the mylonite was likely an andesite. After reassessment of the same sample by this author, it is observed that the illite does not define a shear fabric, as previously stated by Blevings (2008), but is actually oriented normal to the foliation (Figures 3.17C and D). Ribbons of recrystallized quartz ± chlorite define the foliation, with illite orientated normal to the fabric. Therefore the illite sampled in Blevings (2008) actually post-dates the formation of the mylonite foliation and does not date movement along the thrust. Timing of thrusting is not well constrained, but it is likely that the contraction observed in the study area is part of the East Waddington thrust belt. Deformation within this belt is known to have been active by 87 Ma, and possibly earlier, and completed by 84 Ma (Rusmore and Woodsworth, 1994; Umhoefer et al., 1994). Therefore it is likely that movement in the Northwest Copper fault system occurred during this time period. 3.3.2 Large normal faults A large, inferred normal fault crosscuts and offsets the Ravioli thrust fault (Figure 3.3). The normal fault is inferred from field relationships, in particular, outcrops of the Powell Creek 53 Formation to the south of the Ravioli thrust fault. The total intensity magnetic map supports the presence of the normal fault, with outcrop of Powell Creek Formation giving higher magnetic responses than the sedimentary parts of the Tchaikazan River Formation to the south. The northwest part of the mapped area is dissected by a large, normal fault that cuts the Powell Creek Formation (Figures 3.3 and 3.14). It is inferred to dip moderately (>450) to the southwest. The fault is characterized by intense kaolinte-dickite alteration and silicification of the Powell Creek Formation in the hanging wall to the south of the fault plane. The volcanic facies in the footwall of the fault is intensely altered to chlorite and clay. The fault plane contains slickensides that indicate the downward movement of Powell Creek Formation to the south (in the hanging wall). 3.3.3 Other large faults (unknown displacement) Several large fault zones are identified throughout the study area, in particular around the Charlie showing, to the northwest of the Tchaikazan River. Dislocated packages of rocks are often separated by metre-scale voids in outcrop or gouge-rich zones. These zones are typically sub-vertical in orientation, and strike northwest-southeast. It is often difficult to identify a particular sense of displacement in such zones. 3.3.4 Small-scale structures (faults, fractures, veins) Small-scale faults are recognized throughout the study area, and are often delineated by the juxtaposition of different rock-types. Fracturing is locally developed in the Charlie- Northwest Copper area. Shear zones, brittle fracturing, and vein density generally increase to the northwest of the Tchaikazan valley. Southeast-trending, high-angle reverse fault zones are common in the Charlie area. These zones can reach up to several metres wide and are typified by zones of penetrative fractured rock, creating outcrops that are often rubbly in appearance. Veining is a prevalent feature throughout the study area. Several compositions of veins are observed, including: quartz-only; quartz-sulphide; calcite-only; calcite-quartz; and epidote veins. Steronet plots (Figure 3.19) show a general clustering of data, with veins dipping steeply to the northeast and northwest. A significant portion of the veins measured dip shallowly to the north (Figure 3.1 9B and C). In general, carbonate veins and massive quartz veins dip steeply to the north and are observed at high elevations in the Charlie-Northwest Copper area. In contrast, barren and suiphide-bearing dogtooth quartz veins dip shallowly to the north (Figure 3.1 9C). These shallowly dipping quartz veins cross-cut earlier quartz and calcite composite veins in the Charlie area. Shallow to moderate dipping veins were preferentially mineralized, these included veins bearing native copper, chalcocite, and pyrite. 54 Calcite-only veins display a range of orientations; however, there is a clustering of veins that dip shallowly to the north. Quartz-calcite veins measured in the Charlie-Northwest Copper area show a similar pattern in orientation; most dip steeply to moderately towards the north, with a few exceptions dipping shallowly to the northwest (Figure 3.1 9F). Vein compositions, cross cutting relationships, and paragenesis are discussed further in Chapter V. 3.3.5 The Tchaikazan fault The Tchaikazan fault, observed to the north of the Ravioli Ridge, is a northwest-southeast striking high-angle dextral fault (Figure 3.3) (Israel, 2001) and represents the largest structure observed in the study area. The Tchaikazan fault is inferred to possess a strike length of nearly 200 km and suggested offset of 8 km of dextral movement (Israel, 2001). It is inferred to be a step-over fault related to the larger scale Yakalom fault (Schiarizza et al., 1997; Israel et a!., 2006). The position of the Tchaikazan Fault to the northern limits of the mapped study area is in part inferred (Figure 3.3). The fault trends through a glacial valley, with rocks of the Powell Creek Formation to the south and the Tchaikazan Rapids pluton and Taylor Creek Group to the north. In the study area, the fault is exposed in a relatively wide (30 m zone), paralleling the Tchaikazan River. Faulted packages of rocks are observed; highly deformed shales and volcaniclastic rocks attributed to the Tchaikazan River Formation (Israel et al., 2006) form much of the deformed outcrop. A vertical foliation dominates this rare outcrop of the Tchaikazan fault. The Tchaikazan Fault is interpreted to have formed during an initial phase of sinistral deformation during the Cretaceous, and was reactivated during the Eocene in a dextral phase of deformation (Schiarizza et a!., 1997; Israel et al., 2006). The timing of this dextral phase of deformation could be from 77 to 44 Ma, based upon the activity of the Yakalom Fault (77 to 67 Ma) and the Chita Creek Fault (47 to 44 Ma) (Blevings, 2008). 3.4 GEOCHRONOLOGY Rock samples suitable for isotopic dating were collected during the 2006 and 2007 field seasons to precisely constrain the age of volcano-stratigraphic sequences and intrusive rocks. The redistribution of the Tchaikazan River Formation and Powell Creek Formation by tectonic deformation and the unknown age of the major intrusive rocks in the area necessitated the application of geochronology. U-Pb and Ar-Ar geochronological data from this study have been combined with U-Pb and Ar-Ar ages from other studies (Israel, 2001; Israel et al., 2006; Blevings, 2008) to constrain the age of the major stratigraphic units, intrusive rocks, and deformation events. 55 The age of intrusive rocks within the study area was previously unknown. This study provides new data on the timing of magmatic activity within the Tchaikazan River area. The timing of cross-cutting intrusive rocks is important in attempting to reconstruct the magmatic hydrothermal system of the Tchaikazan River area. The application of geochronometers to a suite of rocks such as those at the Hub intrusive complex can potentially yield information about magmatic activity, cooling, and its relationship to hydrothermal alteration. Bulk samples were collected from the Hub intrusive complex, diorite dykes from the lower slopes of the Charlie ridge, and the Northwest Copper pluton. These samples were submitted for U-Pb zircon dating at the Pacific Centre for Isotopic and Geochemical Research (PCIGR) in the Department of Earth and Ocean Sciences at The University of British Columbia. All rocks collected yielded zircons suitable for analysis. Mineral separates of biotite and hornblende were also hand picked from crushed samples and submitted for40Ar-39r analyses. Ages for intrusive samples (06-LH-HUB-36, 06-LH-HLIB-38, O6LH-HIJB-45, O6LH- GOl, O6LH-039-1, and 07-LH-231-1) were obtained from primary biotite or hornblende phenocryst phases (Tables 3.2 and 3.3). All samples yielded 40Ar-39r plateau ages (Figure 3.20) with results summarized in Table 3.3 and the full data set is in Appendix II. 40Ar-39r Geochronology: The Ar-Ar system is useful for dating the cooling ages of intrusive rocks. The parent isotope 40K decays to the daughter isotope 39Ar. Above the closure temperature of the mineral to be dated, Ar flows in and out of the mineral at random. Below the closure temperature, the mineral structure closes and Ar is sealed in. Homblende has a closure temperature of 520°C (Blanckenburg, et al. 2004); therefore ages yielded from 40Ar-39r analysis of hornblende are interpreted to be close to the initial cooling ages of the intrusions. Biotite has a closure temperature of 300°C (Hanes, 1991) and constrains a minimum cooling age for the intrusive rocks. Table 3.2 presents a summary of the samples collected for Ar-Ar analysis. U-Pb Geochronology: Five bulk samples of intrusive rock were submitted for U-Pb laser ablation dating (O6LH-GO1, 06-LH-G02, O6LH-HUB-45, O7LH-009, and O7LH-238). All samples yielded suitable zircon fractions. Results are summarized in Tables 3.2 and 3.4. Concordia plots are shown in Figure 3.21, and the full data set is included in Appendix II. For U-Pb isochrons to be valid it is assumed that the samples remained closed to U and Pb during the lifetime of the system being dated (Dickin, 2005). Zircon mineral fractions are used from the Tchaikazan River samples for age determinations in the U-Pb system. Minerals such as zircon that have remained closed to U and Pb give concordant ages when plotted as 56 206Pb/38U(Dickin, 2005). Table 3.4 presents a list of all samples submitted for U-Pb analysis and a description of their main geological characteristics. 3.4.1 Discussion The U-Pb ages all represent the crystallization ages of the respective intrusions and are generally synchronous with much of the hydrothermal activity in the area. Samples GO 1 and G02 were sampled from dykes that cross-cut Tchaikazan River Formation andesite from the Charlie area (Figure 3.3), and may represent igneous phases related to the Hub intrusive complex to the southeast. Both samples yielded similar concordant zircon ages of 79.9 ± 1.5 Ma and 76.41 ± 0.98 Ma respectively. Therefore the ages confirm that the Tchaikazan River Formation must be older than at least 79.9 ± 1.5 Ma. These ages are comparable to ages generated from samples from the Hub intrusive complex, indicating a period of magmatism from approximately 80 to 70 Ma. Sample O7LH-009, a diorite from the Hub intrusive complex, yielded an age of 81.19 ± 0.78 Ma. These dates are similar to the ages generated from 40Ar-39r analyses of biotite and homblende mineral separates, indicating that the dominant period of magmatism at the Hub intrusive complex was around 80 Ma. Sample O7LH-238 was obtained from the Northwest Copper pluton (Figure 3.21E) and yielded an age of 57.33 ± 0.85 Ma. The Northwest Copper pluton intrudes andesite flow units of the Tchaikazan River Formation. These ages are significantly younger than other dates from the Hub intrusive complex and Charlie areas, indicating that magmatism in the Northwest Copper area is younger. This Eocene age is similar to the Poison Mountain (Cu-Mo) porphyry deposit which is located 75 km east of the study area, where K-Ar geochronology dates the intrusion, potassic alteration, and mineralization 59 to 56 Ma (MINFILE 0920 046). The Poison Mountain granodiorite and quartz diorite stocks intrude rocks attributed to the Lower Cretaceous Jackass Mountain Group (M1NFILE 0920 046). In British Columbia, as in other parts of the Cordillera, mid Cretaceous to Early Eocene magmatism was episodic. Arc magmatism took place dominantly during the Cretaceous time (ca. 144-65 Ma). Data presented here suggests that magmatic activity in the Tchaikazan River area may have been restricted to relatively narrow time periods from around 81-79 Ma (Hub intrusive complex) and 60 — 57 Ma (Northwest Copper pluton and Tchaikazan Rapids pluton) (Figure 3.22). Mineral occurrences are coincident with Late Cretaceous and Eocene age volcanic and plutonic rocks in the Tchaikazan River area. This suggests a history of arc volcanism during the Cretaceous, followed by separate major intrusive events at approximately 80 and 60 Ma. The 57 timing of mineralization at the Hub has been bracketed by dating the main Hub diorite intrusion and a later intra- to post-mineralization dyke. Hence mineralization at the Hub porphyry is restricted to between 81.5 and 69.9 Ma. Although some caution should be exercised in the interpretation of Ar-Ar dates for strongly hydrothermally altered rock, such as those sampled from porphyry deposits (Friedman et al., 2001), the Ar-Ar and U-Pb data presented here are consistent with Late Cretaceous intrusion and mineralization. In general, the Ar-Ar dates are in agreement with the U-Pb ages, where data for both systems exist for the same intrusion. 3.5 FISSION-TRACK THERMOCHRONOLOGY 3.5.1 Introduction The evolution of porphyry copper deposits is strongly affected by the depth of emplacement and the effect this has on the solubility of volatiles and metals in the hydrothermal fluid (see section 2.4). Fluid inclusion samples were prepared from several veins from the Charlie-Northwest Copper area but yielded no independent evidence of pressure and hence depth. Instead here we use low-temperature fission-track thermochronology to constrain the depth at which mineralization occuffed, and to estimate rates of exhumation. Age-elevation plots of multiple thermochronometers for the Hub diorite can produce estimates of exhumation rates, assuming a steady geothermal gradient (Spotila, 2005). The thermochronometers most appropriate for estimating exhumation related to landscape or neotectonic history are (U-Th)/He and fission-track dating (Spotila, 2005). Despite a number of shortcomings, age-elevation plots are often used to infer denudation and uplift rates (Gallagher et a!., 2005). The ability to quantify the exhumation in the Tchaikazan River area allows an estimate of crystallization depth of the Hub porphyry and the rates of exhumation. Fission-tracks are defects in the crystal lattice due to ionization damage resulting from the fission decay of 238U at a rate of 10’6a’ (Fleischer et al., 1975; Wagner and van der Haute, 1992). Minerals such as apatite, zircon, and sphene contain the appropriate range in concentration of 238U over geological time scales (1-1000 ppm) (Gallagher et al., 2005). Fission-tracks are optically observable and occur at a statistically constant rate, these factors make them a practical method of dating minerals (Gallagher et al., 2005). Below a certain temperature, the rate of damage due to fission decay exceeds the rate of damage annealing and fission tracks are retained. AFT dating of apatite, titanite, zircon, and other minerals in rock samples from a region of high relief, especially when coupled with Ar-Ar dating of biotite, homblende, and feldspar, 58 make it possible to reconstruct the uplift and cooling history of such regions. 3.5.2 Methodology A bulk sample of the Hub diorite, collected from the base of the Tchaikazan River valley, (Plate I), was crushed and separated by ALS Chemex in Vancouver, B.C. Crushed samples were then sent to Ray Donelick at Apatite to Zircon Inc. in Viola, Idaho. Apatite mineral separates were dated using fission track dating methods. Two thermochronometers, zircon fission-track (ZFT) and apatite fission-track (AFT) were utilized, and AFT and ZFT ages were determined by the ICP-MS method described by Donelick et al. (2005). The Hub diorite sample was part of a larger regional sample suite of intrusive rocks (Table 5.7), which was collected by Blevings (2008). The sample suite covers a vertical sample transect of approximately 1000 m. The effective closure temperatures for the thermochronometers in this study are: ZFT 200 to 240°C (Reiners and Brandon, 2006); and AFT between 90 and 120°C (Ketcham et al., 1999). Closure temperature is strongly dependent upon cooling rate, with the effective closure temperatures for minerals increasing with increasing cooling rates (Reiners and Brandon, 2006). 3.5.3 Results ZFT from the Hub diorite yielded thennochronological dates of 76.6 ± 4.7 Ma and AFT yielded a date of 31.4 ± 1.8 Ma (Figure 3.25). A summary of thermochronolgy data, including U/Pb, Ar-Ar, ZFT, and AFT is presented in Table 3.3. The correspondence between UPb, 40Ar-39, and ZFT data imply that the Hub diorite cooled to below 220°C immediately after emplacement. For geothermal gradients of 25-30°C/km (assuming an average surface temperature of 10-20°C) this correspondence implies an emplacement depth of no greater than 7-8 km. The AFT date of 31.4 ±1.8 Ma is significantly younger than the emplacement age of the Hub diorite and is thought to be a product of exhumation, rather than the cooling of the pluton. For a closure temperature of 110°C, and a geothermal gradient of 25-3 0°C/km, this corresponds to a maximum depth of 3-4 km at approximately 31 Ma. 3.5.4 Interpretation The suite of intrusive rocks from different elevations was collected for AFT analysis to assess age-elevation relationships (AER) in the Tchaikazan River area. When the samples were 59 plotted on an age vs. elevation plot (Figure 3.24) and a line of best fit plotted through, a corresponding average exhumation rate of 40 m/Myr can be calculated over period between 55- 30 Ma (Figure 3.24). Using this average exhumation rate it would imply that the present exposure of the Hub porphyry was approximately 1 km deeper at 55 Ma than when it passed through the closure temperature. If the same exhumation rate continued back to the time of emplacement it would imply an additional depth of another 1 km, for an initial emplacement depth of 5-6 km. In comparison, the estimated stratigraphic thickness of the units above the emplacement depth of the Hub porphyry is estimated at greater than approximately 4 km; therefore the stratigraphic data is in broad agreement with the ZFT/AFT estimate (Figure 3.25). Contractional movement is known to have occurred prior to the formation of the Hub porphyry deposit at 80 Ma (Umhoefer et al., 1994; Schiarizza et at., 1997). Therefore, the mapped thust fault buried the Powell Creek Formation and contributed to a thickening of the stratigraphic section in the Tchaikazan River area. The Hub porphyry pluton was intruded into the stacked thrust sheet, likely into the Powell Creek Formation. Previous regional studies suggest that the Falls River and Powell Creek formations overlie the Tchaikazan River Formation. The Tchaikazan River Formation occurs beneath a mantle of Powell Creek Formation volcanic and volcaniclastic rocks, which are estimated to reach up to 3-4 km (Schiarizza et al., 1997). Estimates for stratigraphic thicknesses therefore support the hypothesis that the Hub porphyry deposit was emplaced at greater than 4 km depth. 60 BFigure 3.1: A) Regional geology map showing the distribution of terranes, simplified regional goelogy and regional fault system. Modified from Israel et al., (2006). Study area is highlighted by hatched rectangle. B) Stratigraphic chart for Figure 3.1A 5? 51 Bralome fault systen Carpenter Lake Powell Creek Formation Powell Creek Formation Powell Creek Formation Taylor Creek Group Falls River Formation Taylor Creek Group cc t I 0 D 0 a) C) cc a) C) 0 0 0 cc -) C) 0 0 cc I C cc S a) C 00 cc9 oa) LI Tchaikazan River Formation LI Jackass Mountain Group Relay M untain Group a) C a) a) cc -o cc() x a) 0 S 0 C-) a) > a) 0) ccTchaikazan River Area East Waddington belt Northeast of Tchaikazan Fault 61 Insular and SWCB Southeast Coat Belt Intermontane Superterrane Wrangellia and Western Coast Belt w Study Gambler Arc area Tyaughton Basin Methow Basin Cadwallader F Volcanic petrofacies ______ Cherty petrofacies ___ Arkosic petrofacies Bridge River Terrane North America Continental mass Figure 3.2: Schematic summary of the tectonic setting and inferred sediment sources of the Early to Mid-Cretaceous rocks in the Tyaughton-Methow basin (From Garver, 1992; Schiarizza et al., 1997). See hatched box for the location of the study area. - Il Co C 1 CD () () 0 CD 0 Co C, CD 3 CD 0 -h CD CD CD N CD CD -, CD CD Key to the Geology of the Tchaikazan River area J Quaternary cover Intrusive rocks Symbols Northwest Copper syenite - - - - Geologic contact (approximate) Unknown age Northwest Copper pluton -— Bedding 40Equigranular diorite; U-Pb = 57.33 ± 0.85 Ma Hub diorite y y Thrust fault - Identity and existence certain, Porphyriticdiorite/granodiorite, multiphase intrusion: location accurate. Sawteeth on upper U-Pb = 81.19 ± 0.78 Ma (tectonically higher) plate E] Tchaikazan Rapids Pluton - Thrust fault - Identity and existence certain,U-Pb = 89.3 ± 1.4 Ma (Blevings, 2008) location approximate. Sawteeth on upper Volcanic and sedimentary rocks (tectonically higher) plate Powell Creek Formation: Massive fades VV Thrust fault - Identity and existence certain,location inferred. Sawteeth on upperCoherent andesite, to basaltic-andesite lava flows, (tectonically higher) plate volcanic breccias and plagioclase-phyric andesite. Minor volcaniclastic components. (3-4 km thick) __L__ Normal fault - Identity and existence certain, Powell Creek Formation: Non-massive location accurate. Bar on downthrown block2 Non-massive volcaniclastic deposits; polymictic andesite breccias, lahar-like flow units, breccias with tuffaceous matrix. •••• Normal fault - Identity and existence questionable, location approximate. Taylor Creek Group Bar on downthrown block Massive micaceous sandstone, conglomerates and black shale/mudstone. North of the Tchaikazan Fault (2-4 km thick) ...... Strike-slip fault, right-lateral offset. Identity (not mapped in this study). and existence certain, location inferred. Arrows show relative movement Tchaikazan River Formation: Volcanic fades Coherent andesite lava flows, with minor andesite Ductile shear zone or mylonite zone -j breccias/ volcaniclastic sandstones increasing towardsthe top of the unit (1 km thick). Porphyritic feldspar-hornblende dykes Tchaikazan River Formation: Volcano-sedimentary facies Coherent andesite lava flows, interbedded with mudstones, Roads siltstones and sandstones, peperitic contacts observed (500m). Tchaikazan River Formation: Sedimentary facies ii Fossil Locality Interbeddeci cobble conglomerates, sandstones, siltstones c and black shale/mudstones. Fossils locally developed (500m).---- Limit of Geological Mapping Relay Mountain Group LineamentSandstones, siltstones, locally calcareous, fossil-rich conglomerates, including crinoid and bivalve components. A fossil collection was assigned an age of -136- 130 Ma io (Israel, 2001) Not observed in the study area. I Figure 3.4: Geological legend to accompany figure 3.3, showing stratigraphic units, structural and topographical information. 64 Figure 3.5: Photoplate of the Tchaikazan River Formation: sedimentary-dominated facies: A) Well- bedded, planar sandstones. B) Peperitic contact of mudstone and intrusive unit. C) Coarse poorly- sorted sediments with rip-up clasts. D) Syn-sedimentary folding. E) Large-scale folding in Formation. 65 — ; / Parallel bedded mudstones dominate topography Figure 3.6: Photoplate of the Powell Creek Formation A) Andesite clasts within a coarse grained resedimented volcanic-derived matrix. B) Plagioclase-phyric andesite clasts set within an aphanitic andesite matrix. C) Coherent andesite flow unit on top of resedimented volcaniclastic sandstone unit. D) Blanketing of coarse, resedimented volcanic material on top of coherent andesite flow unit at Northwest Copper. E) Similar to D, but observed in the Charlie area. F) 5 m-thick package of resedimented, non-massive Powell Creek Formation. Plagioclase-phyric andesite ciasts Bedded, resedimented volcaniclastic rocks Resedimented volcaniclastic sandstone Coherent andesite flow unit Coherent vesicular andesite flow 66 Table 3.1: Summary table of the lithological units in the Powell Creek Formation and interpreted facies and fragmentation process. Lithofacies observed in the Powell Creek Volcanic facies Coherent vs. Formation from the (Interpretation) Volcaniclastic Facies Mono-polymict Main structures observed Interpreted class Tchaikazan River area of fragmentation Plagioclase-phyric Lava flow Coherent Flow or shallow Monomict Vesicles or no vesicles. Brecciated Lava or intrusion andesite level intrusion flow tops. Chilled flow tops Volcanic breccia Flow dome Volcaniclastic Brecciated post- Monomict or Variable breccia textures: sorting, Volcangenic eruption polymict angularity, phenocryst content Volcanic breccia (primary) Lava flow top Volcaniclastic Autobrecciated Monomict Moderately sorted. Blocky, angular Volcanogenic andesite andesite clasts. Within andesite (primary) matrix commonly Poorly sorted volcanic Debris avalanche Volcaniclastic Syn-volcanic Polymictic Poorly sorted. Non-stratified. Volcanogenic breccia - Lahar deposit from flow dome Massive-graded or diffusely sedimentary bedded. Thickness: <lmto >lOOm. Unconsolidated, non- welded Volcaniclastic sandstone Sub-aerially Volcaniclastic Epiclastic Polymictic Textures common in surface Sedimentary reworked: Rivers, sedimentary environments. Matrix alluvial fans supported. Bedding surfaces common Red andesitic breccia. Competent andesite, minor fracture- coating chlorite. Red, andesitic breccia. Clast-supported volcanic breccia. Lahar-style deposit at base, dominated by metre-scale clasts. Interbedded andesite and reworked volcanics Brecciated andesite, propylitic altered clasts. Interbedded competent andesites and resedimented volcanic breccia. Increasing clast size Felsic dyke, with “snowflake” alteration at contacts. Thickly bedded, altered breccia. Differential weathering of clasts to matrix. flow. Fractured andesite flow top breccia. Competent moderately phyric andesite Figure 3.7: Stratigraphic section through part of the Powell Creek formation dominated by resedimented units A) photo of detailed section A. B) Localized zeolite infilling in volcaniclastic sandstone. C) Coarse sandstone bedding planes and D) Fracture-flow top to andesite flow. Key to geology 2.5cm = 50m 08TSK-\ een O8TSK-02 O8TSK-03 Figure 3.8 - Geology map of the Hub porphyry trenches and location of drillholes 08-TSK-02, 03, 04, and 06, drillholes sighted towards 320° at 60 and 65°: A) Photo looking Northeast along part of the Tchaikazan River and the Hub trenches, B) Contact of the Hub diorite with the crosscutting feldspar-hornblende porphyry dyke, and C) Typical view of the Hub diorite. • Porphyritic diorite Quartz monzanite Diorite dyke Porphyritic hornblende-phyric dyke Extent of geological trench cutting • Position of diamond drillhole I -Ø I) :-1:\ Feldspar- horn blende yry dyke Figure 39: Photoplate showing photos of thin sections from intrusive rocks of the Hub porphyry intrusive complex. A) Typical Hub diorite, porphyritic texture in crossed polars. B) Same as in A but viewed in plane polarized light, C) Large, oscillatory-zoned plagioclase phenocryst. D) Quartz monzonite, with partial sericite alteration replacement of feldspars. 70 No vertical exaggeration Figure 3.10: Interpreted geological cross-sections through part of the Hub porphyry deposit: A) Location of the Hub drill collars and the corresponding magnetic anomaly. B) Interpreted cross section through drill holes O8TSK-04, -02, -03, and -06 (see Appendix I for drill core logs). Notice the hydrothermal breccia at the margins of the diorite bodies and the cross-cutting feldspar-hornblende dyke. C) Same section with differing geological interpretation, the often gradational and biotite magnetite-altered contacts between the Hub diorite and the hydrothermal breccia make the delineation of geological contacts difficult. No vertical exaggeration SE Drill core Inferred geology! Porphyritic Hub diorite LZI Porphyritic Hub diorite Hydrothermal breccia - biotiteHydrothermal breccia + magnetite alteration Andesite Andesite (Powell Creek) Porphyritic feldspar-hornblende dyke Feldspar-hornblende dyke J Overburden Underlying pluton Figure 3.11: Photoplate of the Northwest Copper pluton: A) View facing north of the Northwest Copper pluton. B) Field photo showing variations of diorite within the pluton mass. C) Rounded xenoliths of the country rock within the pluton. D) Thin section of Northwest Copper pluton in crossed polars. E) thin section of diorite dyke in proximity to the Northwest Copper pluton in plane polarized light. 72 H Amazon Ridge Subcropof iwitrusive rock Figure 3.12: Photoplate of the Northwest Copper syenite and associated intrusive rocks: A) Field photograph, showing the subcropping felsic intrusion and distinctive orange colouration of the ridgetop. B) Felsic intrusive rock with dykes of syenite within. C) Syenite in crossed polars, showing sericite alteration to feldspar. D) same as in C, but viewed in plane polarized light and cloudy sericite alteration of equigranular feldsparcrystals. Facing west 73 Figure 3.13: Photoplate of other intrusive rocks found in the Tchaikazan River are. A) Diorite dyke (Gol) from the lower slopes of the Charlie showing. B) Highly weathered, porphyritic feldspar-rich dyke in the Powell Creek formation. C) Fetdspar-phyric dyke with ‘snowflake’ alteration of plagioclase to sericite and illite. D) Characteristic ‘popcorn’ or snowflake’ weathering of plagioclase phenocrysts. E) Thin section in plane polarized light of altered porphyritic dyke, showing epidote replacing hornblende14 (top left). F) Same as in E in crossed polars, showing intense sericite alteration of the matrix. Intense sericite alteration of feldspar phenocrysts — 2800 — 2700 — 2600 — 2500 — 2400 — 2300 — 2200 — 2100 — 2000 — 1900 — 1800 1700 2800 800 2700 700 2600 600 2500 t_- 2500 2400 I_2400 2300 2300 2200 I_2200 2100 2100 2000 2000 1900 1900 1800 1800 1700 1700 1600 1600 1500 1500 1400 1400 14 N 453676 mE, 5669825 mN 451723 mE, 5674897 mN Figure 3.14: Geological cross sections of the Tchaikazan River area: A) A to B, illustrating the thrusted contacts that dissect the study area, and the dominance of the Powell Creek Formation. B) C to D, illustrating the spatial distribution of the three showings (Hub, Charlie and Northwest Copper) and their geological context. Location of cross-sections shown on Figure 3.3, and legend to accompany cross-sections on Figure 3.4. Tagliatelle thrust Linguine thrust U) a) a) E A No verticsl essggerstion North 449356 mE, 5668844mN / + // rut )÷ /v z / Z / Underlying diorite pluton Southeast Northwest U) a) a) E B 449896 mE, 567489 mN No verticsl exsggerstion C D Key to magnetic data: Observed outcrop of the _________ Tchaikazan Rapids pluton N Increasing Magnetic intensity (nT) Figure 3.15: Total magnetic intensity map. Results of an aeromagnetic survey flown by S.J.V. Consultants during the summer 2005. Survey lines were established approximately east-west in the Hub area, whereas they were oriented northeast-northwest over the Northwest Copper area. Observed geological contacts and facies distributions illustrated, local highs correspond well to known intrusive bodies or inferred subsurface plutonic bodies at depth (i.e. Northwest Copper pluton and the Hub intrusive complex). Locally thicknesses of coherent andesite correspond to magnetic highs also. Sedimentary rocks typically display a magnetic low signature. Much of the map area is defined by a relatively low magnetic response. (Klien, 2008). j I L. Syenite and diorite j. / in outcrop ThN* Magnetic low •_7 ( I __ —c - Coherent \\ andesite of the \ \ ‘> Powell Creek 1 ( c— Formation //2 ,s \ / / ( 1: // // Northwest Copper ) / pluton in outcrop ) // ) Subsurface Northwest / Copper plutol Coherent andesite observed in outcrop —h / - “ } ‘j-1 - anefthI9h ‘ -‘ - -‘ 1 subsurface I Magnetic high associated ‘. .J Hu,M,trusIy with Powell Creek Formation .... compiexj ‘I__I - — /l_J .\ -‘ v- - Jz 1 1 76 Figure 3.16- Photo plate of an exposure of the Northwest Copper thrust: A) Field photograph facing east the maroon-coloured volcaniclastic rocks of the Powell Creek formation sit beneath the Tchaikazan River formation, B) The exposed thrust, with intense carbonate and Fe-oxide altered thrust zone, and C) Detail of the calcite veining and rust-coloured, carbonate altered thrust. 77 Figure 3.17: Photoplate of features associated with the Linguine thrust fau’t at Northwest Copper,, exposed to the western edge of the study area, near the Northwest Copper pluton. A) Exposed thrust fault plane, with significant Fe-oxide staining and quartz veining developed. B) Shear fabrics developed in the exposed thrust plane and associated quartz veining. C) Thin section of mylonite fabric from within the Northwest Copper thrust fault, chlorite forms parallel to the fabric, illite normal to the fabric in plane polarized light. D) Same as in C, but viewed in crossed polarized light, notice the anomalous blue interference colour for chlorite and opaque porphyroclast. E) Phyllonite fabric developed in the rocks proximal to the thrust faut.l 78 Figure 3.18: Photoplate, taken facing north, showing the Charlie area (left) comprised of coherent andesite of the Tchaikazan River Formation, juxtaposed against the younger Powell Creek Formation by the Ravioli thrust fault. 79 A N N C N Figure 3.19: Equal-area, lower hemisphere steronet plots showing the orientation of veins in the Charlie-Northwest Copper areas. A) Orientation of quartz veins, showing high density of shallowly dipping to the north. B) Contoured data for quartz veins, showing a clustering of northerly steep northerly dipping veins. C) Orientation of quartz - sulphide veins in the Charlie-Northwest Copper area. D) Plot showing calcite-only veins from the Charlie Northwest Copper area. E) Quartz-calcite veins from Charlie-Northwest Copper area; most dipping to the north. D N E 00 Table 3.2 - Summary of Geochronology samples and rationale for sampling from the Tchaikazan River area 5670561 Northwest Equigranular Diorite Copper 5670167 Northwest Porphyritic diorite Copper Northwest Andesite Determine the age of the Northwest Copper pluton; is it U-Pb related to the Hub intrusive centre? Determine the age of dyke; is it related to the Northwest Ar-Ar Copper pluton? To date the andesite from this outcrop Ar-Ar Field Name UTM Easting Nng Locality Rock Type Justification Yield Hub Intrusive Complex rocks O7LH-009 453430 5668870 Hub trench Porphyritic diorite. Samples forms the main Hub diorite intrusive phase, U-Pb 81.2 ± 0.78 provide a crystallization age O6LH-HUB-45 453434 5668870 Hub trench Feldspar-hornblende dyke Crosscuts the Hub diorite and hydrothermal breccia and is U-Pb itself intensely sericite -altered O6LH-HUB-36 453430 5668870 Hub trench Porphyritic diorite dyke Intimately associated with the main Hub diorite Ar-Ar 80.5 ± 0.42 O6LH-HUB-38 453432 5668870 Hub trench Porphyritic diorite Hub diorite Ar-Ar 79.6 ± 0.42 O6LH-Hub-45 453434 5668870 Hub trench Feldspar-hornblende dyke Hornblende constrain a cooling age for the dyke Ar-Ar 69.6 ± 1.1 Charlie Ridge O6LH-GO1 453136 5669870 Charlie Feldspar-hornblende dyke Determine whether this magmatism is related to the Hub U-Pb 80.85 ± 0.87 or Northwest Copper intrusive centres. O6LH-GO1 453136 5669870 Charlie Feldspar-hornblende dyke Determine whether this magmatism is related to the Hub Ar-Ar 77.5 ± 0.97 or Northwest Copper intrusive centres. O6LH-G02 4553353 5669938 Charlie Feldspar-hornblende dyke Determine whether this magmatism is related to the Hub U-Pb 76.6 ± 0.7 or Northwest Copper intrusive centres. Northwest Copper pluton O7LH-238 447595 O7LH-231 447561 O6LH-039-1 Copper 57.3 ± 0.85 60.0 ± 0.46 22.2 ± 0.70 00 (PI*t***.9e-78565042 (2 . nd*ding J.rror 08.5%) MSV40 0.64. p*obObity40.72 787% 01 the A O6LH-HUB-36 - Hub diorite too 40Ar/°9r (biotite) = 80.53±0.42 Ma (2cy) 65* 56.53*0.4260 (2Riinorof.5%) I MOWO 1.88060546*65.12 I btLde, 88.4% 0088* ftxJ 40 20 40 40 40 100 -Gum ulative39Ar Percent Hub diorite 40Ar/°9r (biotite) 79.56 ± 0.42 Ma (2a) 140 B 120 100 80 40 20 20 46 60 80 100 Cumulative 39Ar Percent C ____ O6LH-HUB-45 100 Feldspar - Horn blende dyke 69.6 ± 1.1 Ma (2a) (0 . 00806*9 0000 08.8%) 20 MOWS. 1.07. p,06e011180.38 0 20 40 88 40 800 Cumulative Ar Percent _____ O7LH-231-1 -Diorite dyke from Northwest Copper 80 = 60.01 ± 0.46 Ma (2cr) 60 40 f’PIotoooese. 60.01*0.46 Mc 22, in*Iod(r,g J-errOr 08.5%) MSWtI 0.93. p7600b46y*0 46 0 20 40 60 80 100 Cumulative Ar Percent E Feldspar porphyry dyke = 77.49 ± 0.97 Ma (2(3) Charlie dyke 20 Gol 0 20 40 60 80 100 -Cumulative39ArPercent Figure 3.20: Ar-Ar plateau ages for representative intrusive rocks from the Tchaikazan River area. A) Sample O6LH-HUB-36. B) Sample O6LH-HUB-38. C) Sample O6LH-HUB-45. D) Sample O7LH- 231-1, Sample06LH-GO1. F)SampleO6LH-039-1. 82 Figure 3.21: U-Pb geochronology diagrams for samples of intrusive rock from the Tchaikazan River area. A) Sample of Charlie dyke, O6LH-GO1. B) Sample of most northerly Charlie dyke O6LH-G02. C) Sample from the main Hub diorite phase, O7LH-009. D) Sample of feldspar-hornblende dyke, O6LH-HU B-45. E) Sample of the Northwest Copper pluton, O7LH-238. A Charlie dyke (south) ci 0) B, O6LH-GO1 cj Hub diorite O6LH-G02 D Feldspar-hornblende porphyry dyke 94 86 G) 0) <78 O6LH-HUB-45O7LH-009 E Northwest Copper Pluton 1) 0) O7LH-238 83 • U-Pb age - Zircon: Hub porphyry D U-Pb age - Zircon: Northwest Copper • Ar-Ar age - Biotite: Hub porphyryHub diorite O7LH-HUB-38 • Ar-Ar age - Hornblende: Hub porphyry _____ D Ar-Ar age - Hornblende: Northwest CopperHub diorite ___ O7LH-HUB-36 O7LH-HUB-45 __________________________________________ North Charliedyke Northwest Copper O7LH-GO1 I diorite dykeO7LH-231 -1 Andesite dyke 5-0—H O6LH-039-1 Northwest Copper pluton O7LH-238 South Charlie dyke O7LH-G02 I I _ ___ North Charlie dykeI I O7LH-GO1 Hub intrusive suite Hub diorite O7LH-009 I I I I 100 80 60 40 2OMa Age (Ma) Figure 3.22: Summary diagram for radiogenic isotope geochronology for the Tchaikazan River area 84 Table 3.3: Summary of thermochronological data from the Taseko Lakes area: including UIPb, Ar-Ar, ZFT, APi, and Zhe results. Sample field name Lab -8 Easting Nortiling Elevation Locationr Rock Type (or Best Field Name U-Pb ArlAr Within AFT (Ma) ZFT (Ma) AFT AFT ZFT (Ma) ZFT 2 (m) Guess) (zircon) (Ma) (Biotite) (Ma) error? (Ma) 2a 07-SB-GEO-O1 891-01 497161 5663935 1850 TC Fine-grained quartz Grizzly Cabin pluton 100 y 49.4 ± 5.5 88±4.9 49.4 11 88.0 9.8 mnnzndiorite 1850 1850 07-SB-GEO-02 891-02 471890 5661590 1420 EMP Porphyritic granite Empress pInion 87.0±1.4 y 33.3 ± 2.5 92.5 ±4.5 33.3 5 92.5 9.0 1420 07-SB-.GEO-04 891-03 473567 5660789 2120 EMP Equigranuiar Mount McLeod 83.2 ± 2.6 y 40.8 ± 2.4 94.7 ± 4.8 40.8 4.8 94.7 9.6 granodiorite granodiurite 2120 2120 07-SB-GEO-05 891-04 476935 5662480 2100 TW Altered equigranular Battlement ridge granite 45.0 ± 6.2 45.6 ± 2.3 45.0 12.4 45.6 4.6 granite 2100 2100 07-SB-GEO-12 891-05 473633 5658101 2550 EMP Coarse grained biotite Mount McLeod 86.0 ± 1.3 y 55.6 ± 3.3 94.7 ± 4.6 55.6 6.6 94.7 9.2 granite granodiorite 2550 2550 06-SB-GEO-2 891-07 450078 5675682 2250 NWC Fine plagioclase Tchaikazan Rapids pluton 89.3 ± 1.4 nol requested 71.4* ± 3.5 0 71.4 7.0 hornblende porphyry 2250 2250 07-LH-GEO-03 891-06 453432 5668870 1575 HUB Purphyritic Hub diorite intrusion 81.19 ± 0.78 79.56 ± 0.42 y 31.4 ± 1.8 76.6 ± 4.7 31.4 3.6 76.6 9.4 diorite/granodlurite 1575 1575 TC - Twin Creeks; EMP - Empress; TW- Taylor Windfall; NWC - Northwest Copper; HUB - The Hub ZIte closure 180 ZFT closure 220 AFT closure 110 geothermal gradient (CIkm) 30 O7SB-GEO-12 - U-Pb -- O7SB-GEO-12-ZFT O7SB-GEO-12-AFT I--I- 07SB-GEO-04-UIPb F---I O7SB-GEO-04-ZFT -—-- 07SB-GEO-04-AFT i-.-i 07SB-GEO-02 - U/Pb I-’-I- 07SB-GEO-02-ZFT I_—O--J- - O7SB-GEO-02-AFT 1-0-I E Co(0 O7SB-GEO-01 - U/Pb O7SB-GEO-01 -ZFT i——I O7SB-GEO-01 -AFT __- O6SB-GEO-02- U/Pb I-.--I- O6SB-GEO-02-ZFT i-a-i O7LH-GEO-03-ZFT i—e---I- 07LH-GEO-03-U!Pb 07LH-GEO-03-AFT j-4 I I I I I I 0.0 20.0 40.0 60.0 80.0 100.0 120.0 Age (Ma) Key to samples 2 a error Thermochronometer • Mt McLeod granodiorite - • Tchaikazan Rapids pluton 0 - ZFT o Mt McLeod granodiorite * Hub diorite - U/Pb • Mt McLeod granite * Grizzly Cabin pluton 0 - AFT Figure 3.23: Plot showing all age data for the suite of samples from the Taseko Lakes area; showing ZFT, U/Pb and AFT ages for each sample. All U/Pb and ZFT ages are within 2a error of each other. Additional sample data from Blevings (2008). 86 Thermoch ronometer 0 -AFT 4000 3500 / 3000 , , , 2500 E ‘/ _________________________________________ / rrir, Key to sample location . 1500 ____________ ____________ 0 Empress (O7SB-GEO-02) W • The Hub diorite (07-LH-GEO-03) 1000 / - • Grizzly Cabin (07-SB-GEO-01) 500 • Mt McLeod Gre (07-SB-GEO-12) • Mt McLeod Gdr (07-SB-GEO-04) 0.0 20.0 40.0 60.0 80.0 100.0 120.0 Age (Ma) Figure 3.24: Age-Elevation plot of intrusive igneous rocks from the Taseko Lakes area, illustrating the best-fit line for the exhumation rate. Samples were collected over a range of elevations; the Hub diorite was collected from the valley floor. See Table 3.3 for full dataset. Additonal samples from Blevings (2008). 87 Figure 3.25: Schematic diagram illustrating the emplacement and exhumation history of the Tchaikazan River area. Data compiled from AFTIZFT analysis. Intrusion of Hub diorite -80 Ma 60 Ma Intrusion of Northwest Copper pluton 1 km 2 km 3 km 30 Ma -c 0. 4km Present day 5 km Diorite dyke at 60.01 ± 0.46 Ma (Ar/Ar horn blende) 6 km 7 km 8 km Present depth of Hub porphyry AFT (110°C) Intrusion at 57.33 ± 0.85 Ma (U/Pb zircon) Northwest Copper pluton Hub diorite intrusion \ Present erosion level Depth of closure temperature 00 00 CHAPTER IV PALAEOGEOGRAPHY AND TECTONIC SETTING OF THE TCHAIKAZAN RIVER AREA 4.1 LOCAL PALAEOGEOGRAPHICAL SETTING The Tchaikazan River area likely represents a transitional depositional environment between arc and marginal basin. The volcanic-dominated lithologies belonging to the Tchaikazan River Formation, Falls Creek Formation, and Powell Creek Formation are related to the Gambier arc. During the Cretaceous, the Gambier arc provided a sediment source from the west for the Tyaughton-Methow sedimentary basin (Figure 3.2). Eastward migration of the Gambier arc and uplift and erosion of Early Cretaceous units supplied sediment to the upper portions of the syn tectonic Tyaughton Basin (Garver, 1992). The translation of the Gambier arc and Southwest Coast Belt to the west was accompanied by a southwards movement, juxtaposing rocks of the SWCB that are more “Stikine-like’ to the west, with rocks of the SECB that are more ‘Cadwallader-like” to the east. The Cadwallader terrane is a Late Triassic volcanic arc that was originally situated to the east of the Bridge River Complex, but is now found throughout most of the length of the SECB (Umhoefer and Schiarizza, 1996). By 1 30 Ma the Southwest and Southeast Coast Belts were amalgamated, based on the overlap of Early Cretaceous rocks onto Cadwallader associated rocks (Israel, 2001). Sinistral translation of the SWCB is inferred during Mid-Cretaceous time, this is coincident with regional unconformities separating Early and mid Cretaceous rocks (e.g., between Relay Mountain and Taylor Creek Groups) (Israel, 2001). The continued eastward migration of the Gambier arc was characterized by the deposition of the voluminous deposits of dominantly subaerial continental arc rocks of the Powell Creek Formation (Israel et al., 2006). Closure of the Tyaughton-Methow basin and regional uplift was initiated by contractional deformation (Figure 4.1). This period of contraction was followed by volcano- sedimentary deposition, as evident in the Taylor Creek Group and Powell Creek Formation. Throughout much of the Cretaceous period the Tchaikazan River area underwent volcanic eruptions. Magmatic activity increased towards the upper parts of the Tchaikazan River Formation, eventually overwhelming the predominantly sedimentary system. The extrusion of magma and clastic sedimentation occurred contemporaneously throughout the Late Cretaceous. The depositional environment of the Tchaikazan River Formation sedimentary facies suggests submarine deposition. Fine-grained mudstones, siltstones, and sandstones are interpreted as incomplete turbidite sequences, indicating they were deposited in a slope environment. Graded bedding, rip-up clasts, and syn-sedimentary folding exhibited by the 89 sedimentary facies characterize deposition in relatively deep-water environment. Texturally and compositionally mature sandstones are rare in the succession, however they indicate the addition of sediments from continental sources, as well as volcanic environments such as the Gambier arc (Blevings, 2008). The Tchaikazan River Fonnation likely represents a shallowing upwards sequence of marine rocks, deposited near an active arc region. The Tchaikazan River Formation shows three main characteristic volcano-sedimentary associations: (1) deep marine, fine-grained sediments with intercalated coarse-grained sediments; (2) intercalated volcanic flows and volcaniclastic sandstones; and (3) debris flows, igneous breccias, and sub-aerial lava flows (Figure 4.2). Shallowing of the depositional system is inferred from increased proportions of coarse pebble conglomerates, interbedded with volcaniclastic sandstones. Terrestrial plant fossil material from the sedimentary facies also supports a shallowing of the succession and addition of terrestrial sources. The increase in volcanic material towards the stratigraphic top of the Tchaikazan River Formation suggests a progressive increase in arc related volcanism. The caic-alkaline signatures of the volcanic rocks place them into volcanic arc-related and marginal basin settings, produced by subduction under the continental margin. In general, peperite domains are less than a few m3, occurring along contacts between fine-grained sediment and small intermediate composition intrusions. Peperitic textures indicate the intrusion and interaction of magma into wet sediment or sediment-laden water (Skilling et aL, 2002; Waichel et al., 2007). Sedimentation and magmatism must therefore have been contemporaneous. The presence of peperitic intrusions in the inferred upper parts of the formation suggests that wet, unconsolidated sedimentary packages persisted during the aggradation of the formation. Although not mapped in this study area, the Falls River Formation regionally overlies the Tchaikazan River Formation. Israel (2001) suggests similar stratigraphic relationships for the Falls River Formation as observed in the Tchaikazan River Formation, and states that the Falls River Formation comprises intermediate to felsic composition volcanic rocks and a dominance of sedimentary rock-types. Hence, the Tchaikazan River and Falls River Formation likely developed under similar near shore marine depositional setting with associated fan system and volcanic input from the nearby active Gambier Arc. The Powell Creek Formation is the youngest observed lithological unit in the study area and is comprised of coherent andesite flow units, andesite breccias, and lahar-like, resedimented volcaniclastic deposits. The Powell Creek Formation exhibits aspects of deposition that can be attributed to both sub-aqueous and sub-aerial environments (Figure 4.3). The purple/maroon colour of much of the formation suggests abundant hematite and oxidization owing to the 90 subaerial environment. Volcaniclastic rocks are often well-bedded and indicative of sub-aqueous deposition. Units comprise thick to massively bedded, poorly sorted, matrix-supported, cobble conglomerates. The matrix to these breccias was mostly granular in texture and plagioclase phyric clasts are often rounded. These massive, breccia flow units are interpreted as lahar-like deposits, suggesting sub-aerial deposition. In conclusion, the features attributed to the rocks within the Tchaikazan River area reveal protracted periods of marine deposition within a fluctuating environment, ranging from submarine to periods of sub-aerial deposition. In terms of relative sea level, the area experienced a transgression throughout the deposition of the early Cretaceous Tchaikazan River Formation sedimentary-dominated facies. The volcano-sedimentary facies, with increased volcanic input from proximal volcanic dome complexes (Figure 4.3), was deposited until the sedimentary system was overwhelmed by volcanic material at the top of the Tchaikazan River Formation. Renewed magmatic input is a product of the volcanic arc setting. Deposition of the Powell Creek Formation indicates a return to emergent, sub-aerial deposition of volcanogenic and volcaniclastic rocks. In contrast to the largely water-driven sedimentary processes developed in the older Tchaikazan River and Falls River Formations, the Powell Creek Formation was dominated by the construction and destruction of flow dome complexes. Proximal andesite lava flows, and volcanic breccias would have been shed from the flanks of the domes. Volcaniclastic material, typical of the Powell Creek Formation, was likely formed from channel- and fluvial-dominated processes on the flanks of the volcanic dome complexes (Cas and Wright, 1988). Based on these observations it is envisaged that the Powell Creek Formation represents a regionally extensive period of andesite-dominated volcanism, with multiple source vents and possibly overlapping stratocones (Figures 4.2 and 4.3). Steep-sided stratovolcanoes and the sedimentary processes that accompany them, similar to those envisaged for the Bajo de la Alumbrera deposit (Harris eta!., 2006), are suggested as the volcanic setting for the Powell Creek Formation in the Tchaikazan River area. The relatively thick (several 100 m) debris flows and sedimentary volcaniclastic flows are typically associated with mass-wasting processes and degradation of stratocones (Cas and Wright, 1988). 4.2 TECTONIC DEVELOPMENT The physical expressions of deformation observed and documented within this study can be placed into the regional deformation history as previously documented by Israel et al. (2006). This deformation history of the area is divided into three separate events, Dl to D3 (see section 3.3). 91 The thrust faults observed in the Northwest Copper area coffelate well to the Dl events described by Israel (2001) and Israel et al. (2006). They dip moderately to the southwest and generally strike east-west, placing rocks of the Tchaikazan River Formation over those of the Powell Creek Formation. These faults are interpreted as evidence for regional contraction and are attributed to the East Waddington thrust belt, which is known to have been active from —-87, possibly earlier, and finished by 84 Ma (Rusmore and Woodsworth, 1991; Umhoefer et al., 1994; Israel et al., 2006). A minimum age is provided by a concordant U-Pb zircon age of 68 ± 0.5 Ma for a post-tectonic pluton (Rusmore and Woodsworth, 1991). The Ar-Ar illite age of ——60.5 Ma from mylonite reported by Blevings (2008) (discussed in section 3.3.1) is somewhat younger than deformation recorded by the 87-68 Ma age of the East Waddington Thrust Belt, however, re evaluation of the sample concluded that the illite did not define the shear fabric in the sample. The illite in the mylonite sample could represent weak intermediate argillic alteration, probably associated with the Northwest Copper pluton. The Northwest Copper pluton is dated by U-Pb and Ar-Ar to —-57-60 Ma. Faults located in the Charlie area could fall into the D2 regional deformation framework as they possess many of the physical attributes described by Israel et al. (2006) for D2 faulting: they are typically sub-vertical in orientation, with faults zones of several meters in size, and cut rocks of the Tchaikazan River Formation. Neither throw nor sense of movement across a single fault is was able to be determined, owing to the similar nature of rocks in the hanging and footwalls of these faults. The final phase of deformation (D3) has been linked to movement of the Tchaikazan Fault (Israel et al., 2006). The Tchaikazan Fault was likely active during late Cretaceous and was subsequently reactivated during the Eocene as a dextral strike-slip fault (Israel et al., 2006). 4.3 FELSIC INTRUSION HISTORY There are two temporally distinct periods of intrusive activity. The first began —80 Ma, evident in the Hub intrusive complex and accompanying diorite dykes in the Charlie area. The second, evident in the Northwest Copper intrusive complex, began ——60 Ma. U/Pb and Ar-Ar data suggests that the first episode of intermediate to mafic magmatism was coincident with contractional deformation. McLaren (1990) stated that igneous intrusions, at times associated with volcanism, occurred during much of the interval from Mid-Cretaceous though to Neogene. These intrusions coincided with major deformational events in the region, and spanned the change from dominantly contractional structural regime in the mid- to Late Cretaceous to one of dextral strike-slip and normal faulting in the Cretaceous and Tertiary. 92 The age of low-grade metamorphism is not well constrained. It may in part have occurred during Cretaceous contractional deformation, as greenschist-facies regional metamorphism of this age is well documented in the deeper parts of the eastern Coast Belt orogen to the south (McLaren, 1990). Alternatively, or in addition, some of the metamorphism may be attributed to terrane-specific event (Triassic-Jurassic accretion subduction). 4.4 EXHUMATION An average exhumation rate of 40 mlMyr (calculated from Figure 3.24) indicates that the present exposure of the Hub was approximately 1 km deeper at 50 Ma than when it passed through the closure temperature for apatite. If the calculated exhumation rates stayed consistent throughout the geological history of the region, to the emplacement of the Hub porphyry at 81 Ma, it would imply an additional 1.5 km and a total depth of 5-6 km. Regional crustal shortening occurred at 87 Ma with the development of several thrust slices in the Tchaikazan River area. The present erosion level illustrates the emplacement of the Hub pluton in the Powell Creek Formation; with two successive thrust slices juxtaposed above (Figure 4.4). 93 Jurassic Middle Jurassic accretion of the Insular superterrane. Deposition of the Tyaughton-Methow basin on the Cadwallader and Bridge River terranes begins in the Middle Jurassic. The source material for the Tyaughton-Methow basin is likely the Stikine-Cadwallader arc material. Early Cretaceous A A A A Sinistral movement, coupled with subduction, likely within a transpressional system. The Gambier Arc is built upon Insular superterrane basement and faulted-slices of the Stikine-Cadwallader arc. Jura-Cretaceous arc provides a source to the west for the Methow-Tyaughton basin. Sinistral movement is active until at least 89 Ma. Mid-Cretaceous contractional ‘crunch’ is exhibited by the NE-directed Waddington thrust belt and the SW verging Coast Belt thrust system. Figure 4.1: Tectonic evolution for the South east Coast Belt (SECB) and the Tchaikazan River area. Modified from Israel et al. (2006). A A A A AA ‘A AA I Mid-Cretaceous I IA IAA • Study area East Waddington belt (EWB) and Gambier Group. Intermontane superterrane Methow-Tyaughton basin Insular superterrane Bridge River Accretionary complex 94 Lava flows, turbidites and volcanic-derived sandstones and coarse conglomerates. Deposition by resedimentation of volcanic products. Sub-aqueous deep marine turbidite deposition within submarine fan environment. Figure 4.2: Reconstruction of the volcano-sedimentary system within theTchaikazan River Formation, including major facies associations and u tectonic setting (modified from Israel, 2001). Key to sedimentary facies = Coarse andesite clast = Resedimented volcanics = Sandstones, siltstones = Siltstones, mudstones Ash deposited distal to vent Multiple source vents for volcanic material Autobrecciation proximal to vent and are typically andesite in composition. Flow-front breccias are a common facies. Debris flows and resedimented volcaniclastic units. Sub-aerial lava flows and associated pyroclastic deposits. / Figure 4.3: Schematic reconstruction of the volcanic facies of the Powell Creek Formation: primary volcanic, resedimented volcanic rocks and volcaniclastic rocks (After Cas and Wright, (1998). 96 A B Figure 4.4: Schematic reconstruction of the development of thrust faults through the Tchaikazan River area. A) Regional stratigraphy prior to thrusting event. B) Regional contraction and development of initial thrust along lower basal detachment surface and send thrust. C) Steep thrust cutting through stratigraphy, bringing Tchaikazan River Formation above Powell Creek. D) Tilting of thrusted sequence, with present day cross section overlain. Stratigraphic sequence prior to initiation of thrusting Pc - Powell Creek Formation Try - Tchaikazan River Formation - volcanic Trt - Tchaikazan River Formation - volcano-sedimentary Regional contraction - Thrust development - Stage 2 Lower detachment Trs - Tchaikazan River Formation - sedimentary D Tilting of sequence and present erosion surface CHAPTER V PHYSIO-CHEMICAL MANIFESTATIONS OF MAGMATIC HYDROTHERMAL SYSTEMS IN THE TCHAIKAZAN RIVER AREA 5.1 DEPOSIT SCALE FRAMEWORK OF PORPHYRY MINERALIZATION The study area can be divided into three hydrothermal alteration and mineralization domains: the Hub Cu-Mo porphyry deposit; the Charlie Au vein prospect; and the Northwest Copper Cu vein prospect. The Charlie and Northwest Copper prospects are here described together, owing to the similarities in the character of observed hydrothermal alteration and mineralization (Figure 5.1). The Hub porphyry is located within the Tchaikazan River Valley, where it is exposed alongside the Tchaikazan River (Figure 5.2; Plate I). Exposure is generally poor and limited to a few hundred metres of exposure within man-made geological trenches. Additional sub-surface data is available from four drill holes. Copper mineralization is hosted in the Hub diorite and surrounding andesite host rocks. Evidence of hydrothermal activity includes: a phase of hydrothermal breccia; biotite-magnetite alteration; locally intense sericite and propylitic alteration; and chalcopyrite ± bomite ± molybdenite mineralization. The Charlie and Northwest Copper prospects are located to the northwest of the Hub porphyry deposit (Plate I). Together these areas comprise greater than 90% of the study area. Numerous mineral showings, containing chalcopyrite, pyrite, native copper, galena, and tetrahedrite, are located in the talus-laden slopes rising from the Tchaikazan River valley, and evidence for hydrothermal alteration is variably developed across these areas. 5.2 GEOLOGICAL SETTING 5.2.1 The Hub Porphyry Previous to this study, the geological context of the Hub porphyry was poorly documented and understood. The outcrops of the Hub porphyry deposit, located at the Tchaikazan River, are isolated from the nearest outcrops to the north (within the Charlie area). Therefore, much uncertainty surrounded the geological context of the Hub deposit. There is no observed fault between the outcrops of the Hub porphyry deposit and the nearest outcrops at the Charlie area. However, aeromagnetic data does indicate that a large normal fault could be interpreted to occur between the Hub porphyry and the Charlie-Northwest Copper area and this is the geometry shown on figure 3.3. Faulting is prevalent in the surrounding area (Charlie and 98 Northwest Copper), and it is possible that the Hub has been displaced to some degree relative to the Charlie and Northwest Copper. The Hub porphyry deposit is an intrusive complex comprising diorite, granodiorite, quartz monzonite and feldspar-homblende dykes. The host/wallrocks to these intrusions are not observed in outcrop, but are seen at depth in drill holes. 5.2.2 Charlie-Northwest Copper The Charlie-Northwest Copper area comprises fault-bounded Cretaceous volcano- sedimentary rocks of the Tchaikazan River and Powell Creek Fonnations. The Powell Creek Fonnation dominates the Northwest Copper area. Regionally it is estimated to have a thickness of up to 3 km (Schiarizza et a!., 1997). Bedding in resedimented volcanic units and contacts of coherent lava flows of the Northwest Copper area generally dip moderately to the southwest. The Tchaikazan River Formation is thrust above the Powell Creek Formation in the southeast part of the study area. Bedding within the sedimentary rocks of the Tchaikazan River Formation generally dip steeply towards the south-southwest. Several large-scale lineaments in topography are observed within the Charlie-Northwest Copper area and are interpreted as large- scale faults of unknown displacement and kinematics. There are several outcrops of intrusive lithologies; the Eocene Northwest Copper pluton, dated at ‘57 Ma (U-Pb zircon); a small outcrop of syenite dyke; and numerous feldspar-hornblende, and diorite porphyry dykes. 5.3 HYDROTHERMAL ALTERATION Hydrothermal alteration is the chemical replacement of the original minerals of a rock by new minerals; a hydrothermal fluid delivering chemical reactants and removing the aqueous reaction products (Reed, 1996). In this study it is important to distinguish hydrothermal alteration from mineralogical change brought about by regional metamorphic hydration of minerals. Difficulty arises when confronted with mineral assemblages containing the minerals albite, chlorite, epidote, and carbonate (see section 3.2). These minerals match descriptions in literature of ‘propylitic’ hydrothermal alteration of intermediate to mafic rocks also represent greenschist metamorphic assemblage (Reed, 1996; Wilson et a!., 2003). Reed (1996) stated that the term ‘propylitic’ should be restricted to mineral assemblages that include all of the minerals albite, chlorite, and epidote. This definition allows propylitic alteration to be distinguished from the processes of albitization, chloritization, and epidotization. In a regional context, the background alteration of the volcanic rocks of the Tchaikazan River Formation and the Powell Creek Formation comprises weak to intense chiorite-epidote-calcite development. 99 5.3.1 The Hub Porphyry Hydrothermal Breccia A biotite ± magnetite cemented/matrix hydrothermal breccia is volumetrically the second-most extensive lithology observed at the Hub showing after the Hub diorite phase. Recent drilling has shown the breccia extends to a depth of at least 260 m. The hydrothermal breccia is typically ‘—60% matrix/cement, 30% clast material, and 0-10% open space. The fragmented nature of the breccia is observed at both outcrop- and thin section-scale. Hand samples of the breccia are composed of comminuted rock fragments. Fragments are dominated by compositions reflecting the immediate walfrocks, including a plagioclase-phyric andesite, diorite, quartz vein fragments, and rare monzonite (Figures 5.3 and 5.4). All fragments appear to have undergone some degree of hydrothermal alteration. Fragments are typically sub-angular to sub-rounded and 1-5 cm in diameter, although larger blocks of andesite (metres in size) are present, based upon logging from drill core. The breccia consists in part of fine-grained matrix, composed of fragmental plagioclase phenocrysts. Pervasive biotite ± magnetite alteration can mask clast composition owing to the black colour, and often fme-grained texture of the rock. Chemical precipitates such as magnetite and disseminated sulphides, which appear to infill void space, sometimes cement clasts. The breccia is most common in the upper parts of drill holes, where it dominantly forms along the margins of the Hub diorite. Clasts are chaotically organized and no jigsaw-fit textures were observed. The lack of jigsaw-fit textures indicates relative rotation and transportation of the clasts, although transport distances may not be significant. Magnetite ± biotite alteration The magnetite ± biotite mineral assemblage is confined to the Hub porphyry deposit (Figure 5.1). The magnetite ± biotite alteration ranges from intense biotite-only alteration, to biotite ± magnetite, and pervasive magnetite. The locally intense, fine-grained form of the biotite-magnetite alteration and subsequent overprinting by sericite-chlorite alteration, followed by brecciation and mineralization sometimes impede identification of protoliths. Intense biotite ± magnetite alteration is characterized by shreddy biotite in the matrix of the altered host rock and replacing mafic minerals, often accompanied by fine-grained magnetite. Strong biotite-only alteration is restricted to the hydrothermal breccia, with weaker magnetite only alteration observed in the Hub diorite. In the andesite walirocks (observed in drill core), biotite ± magnetite alteration is dominated by microscopic magnetite and biotite, which obliterates original texture. Although magnetite and biotite are the dominant phases, this 100 alteration assemblage also contains minor quartz as a cement phase. Alteration biotite occurs in four important modes: (1) as hairline veinlets, together with chalcopyrite, quartz and muscovite; (2) as fine-grained, saccharoidal pervasive replacement of groundmass; (3) stubby crystals replacing primary hornblende and biotite; and (4) as euhedral large biotite phenocrysts replacing igneous biotite (Figure 5.5). Hydrothermal biotite typically replaces magmatic biotite and hornblende, and is often pseudomorphed by later chlorite. The breccia is pigmented by groundmass biotitization. The magnetite is typically fine-grained (<1 mm) and pervasively in the groundmass of the Hub diorite. Sericite alteration Weak to moderate sericite alteration is observed throughout much of the plagioclase phenocrysts of the Hub diorite. Locally sericite alteration partially replaces plagioclase phenocrysts of the Hub diorite (Figure 5.6A). Sericite alteration cross-cuts the diorite, hydrothermal breccia, and biotite-magnetite alteration. Intense, texturally destructive sericite alteration is observed within the youngest feldspar-homblende dyke at the Hub showing (Figure 5.6B and C). Chlorite ± epidote alteration Chlorite and epidote are typically observed together within the Hub diorite. The replacement of primary biotite, plagioclase, and hornblende by chlorite is common (Figure 5.6D). The matrix of the diorite often exhibits a strong green tinge; attributed to an influx of chlorite. Secondary biotite of the magnetite-biotite alteration is pseudomorphed by chlorite, seen as shreddy chlorite after shreddy biotite (Figure 5 .6E). Fine-grained chlorite ± epidote alteration is locally developed. Later chlorite alteration has affected the magmatic, disseminated, and vein replacement biotite in the biotite ± magnetite alteration zone. Silicification Silicification of the Hub diorite is commonly manifested as replacement of plagioclase feldspar by quartz. Pervasive silicification results in a complete destruction of primary igneous textures in the diorite and a replacement with fme-grained, matte-luster silica. The fine-grained nature and green-cream colouration distinguish the silicified areas from the host Hub diorite. The silicified areas are typically up to 5 cm in thickness and appear to coalesce into several stringer like areas of silica. Contacts of the Hub diorite with these silicified regions are generally sharp. 101 Locally, contact zones between the Hub diorite and the hydrothermal breccias are also silicified (Figure 5.3). Once again these silicified zones are generally sharp, extend up to 5 mm into the host Hub diorite, and are generally parallel to the contact. 5.3.2 Charlie-Northwest Copper Propylitic alteration assemblage A chlorite-epidote ± calcite ± albite mineral assemblage is widespread throughout the andesite rocks of the Tchaikazan River and Powell Creek Formations in the Charlie and Northwest Copper areas (Figure 5.1). Typically these alteration minerals replace primary igneous phases, such as hornblende, biotite, and plagioclase (Figure 5.7A). In this study propylitic alteration assemblage is divided into an index, based on the intensity of alteration. The index ranges from 1 to 3, where 1 equates to intense epidote alteration (Figure 5.7A), 2 is strong epidote veining and pervasive chlorite alteration (Figure 5.7B), and 3 is chlorite-calcite-albite ± epidote. As the propylitic index increases, the number of mineral phases also increases. In the propylitic mineral assemblage (1) epidote alteration and vein epidote (Figure 5.7C) are largely found proximal to large-scale faults, and/or quartz-carbonate veining, particularly in the Northwest Copper area (Figure 5.1). In these altered regions epidote typically replaces mafic phenocrysts of the andesite rocks assigned to the Tchaikazan River and Powell Creek Formations. Fine-grained massive, epidote pods and vein epidote are located near to the Northwest Copper pluton. Interestingly, andradite garnet was found in an isolated sample within this alteration assemblage suggesting components of higher temperature calcic alteration (Figure 5.7D). The proximity to the Northwest Copper pluton may have provided the heat and fluid necessary for epidote alteration. Strong hydrofracturing often associated with shallow intrusions, such as the Northwest Copper pluton, may increase the permeability of host rocks, not only for magmatic-related metasomatic fluids, but also for later, cooler, meteoric fluids (Meinert, 1992). Chlorite and epidote are abundant in the propylitic mineral assemblage (2), and the rock is altered to a dark green mass, with little original texture preserved and fine-grained, partial to complete replacement of host rock matrix and phenocrysts by chlorite and epidote. Strong chlorite ± pyrite alteration was observed on fracture planes in drill core from the Ravioli Ridge area (O8TSK-05, see Appendix I). Chlorite is ubiquitous as mafic mineral replacements, fracture coatings, and veinlets within the Northwest Copper area and is found in association with magnetite, hematite, and quartz. Copious epidote clusters are observed in the matrix of the 102 andesite, within plagioclase sites, and also within some quartz veins. Where epidote is observed, crystals tend to be small, euhedral to subhedral, and located within degraded plagioclase in association with sericite. Minor prehnite (Ca2AIAlSi3Oio(OH))was identified by SWIR analysis and when observed it was often in association with fine-grained epidote, or intergrown with chlorite. Propylitic mineral assemblage (3) is the most widespread in the study area (Figure 5.1). Chlorite-epidote ± carbonate ± quartz ± albite is developed in the andesite rocks of the Powell Creek and Tchaikazan River Formations. It is characterized by the partial replacement of plagioclase, homblende, and clinopyroxene phenocrysts by fine-grained chlorite and epidote, and with chlorite, calcite, and fine-grained quartz in the matrix. Phyllic alteration Phyllic or sericitic alteration in the Charlie and Northwest Copper areas is locally developed. Phyllic alteration contains sericite, minor quartz, chlorite, and hematite. It occurs on the Ravioli Ridge area, in andesite and feldspar porphyry dykes, where it is typically expressed as the replacement of plagioclase and mafic minerals by sericite. The quartz-pyrite-sericite assemblage is developed in parts of the Tchaikazan River Formation volcanic facies. Sericite alteration may occur as blebs replacing the matrix and phenocryst components of coherent lava flow units. Sericite is common as selvages to quartz-sulphide veins across the area, including the Hub. Kaolinite- dickite -illite alteration (Advanced Argillic) Areas of advanced argillic alteration (kaolinite, dickite, and halloysite; identified by SWIR techniques) locally cross-cut sericite alteration. The advanced argillic alteration is locally developed on the western flank of Ravioli Ridge (Figure 5.1). The zone is proximal to a large east-west, striking dip-slip fault (Figure 3.3). Rocks of the Powell Creek Formation located in the hanging wall appear to have undergone significant silicification. Drilling has shown that clay alteration is known to occur to a depth of at least 125 m from the surface (O8TSK-05, Appendix I). Kaolinite, dickite, montmorillonite, and halloysite (Figure 5.7E) locally destroy original rock constituents and textures. Clay imparts a distinctive white/yellow colour and mottled texture to the rock, which strongly contrasts surrounding maroon-coloured Powell Creek Formation. Typical temperatures of formation for kaolinite and dickite are -200-3 00°C and 125-28°C, respectively (Keller, 1978). 103 Quartz-diaspore alteration (Advanced Argillic) The assemblage quartz-diaspore was observed in a locality along the Ravioli ridge (Figure 5.1). The alteration assemblage is accompanied by tetrahedrite in a 15 m wide linear zone, oriented approximately east-west. The zone was identified by an abundance of malachite and azurite coating rock surfaces in outcrop. Diaspore is recognized in hand specimen by a finely mottled alteration effect and from SWIR studies on several hand samples. Acicular diaspore forms the infill to the breccia with fine-grained quartz (Figure 5 .7F). The rock is brecciated, with clasts of quartz-dominated material within a diaspore dominated matrix (Figure 5.8). Tetrahedrite is typically coarse-grained and occurs at the margins of the quartz-diaspore dominated clasts (Figure 5.9). Silicification occurs peripheral to many of the clasts, and can reach up to 10 mm into the host altered volcanic rock. Clasts are dominantly 1-3 cm in size and are assumed to be of andesite composition, similar to the surrounding wallrocks of the Powell Creek Formation. The matrix to the breccia is typically pervasively altered to quartz and the protolith is not identifiable, although is assumed to be of andesite composition. Diaspore is typically classified as a mineral that occurs as part of the advanced argillic alteration of high sulphidation epithermal deposits and upper parts of some porphyry systems (Arribas and Hedenquist, 1995; Rye, 1993). Typical temperatures for the formation of diaspore in the active Phillippine volcanic systems are 200-300°C (Khasgerel et al., 2006). Its presence suggests moderate temperatures (200-300°C), very low pH (<3), high f02, and aluminous rich environment (Khashgerel et al., 2006; Keller, 1978). Silicification Silicification is the least abundant of the alteration types in the Charlie-Northwest Copper area, occurring proximal to large-scale faults (Figure 5.1). Primary textures are commonly obliterated. Silicification is locally developed in the Powell Creek Formation, where the resedimented facies is most often affected by this style of alteration. This preferential development is possibly a function of the greater permeability and greater fluid flow by the non massive volcanic facies. 5.4 PARAGENESIS Hydrothermal alteration, veining, and textural relationships of suiphide minerals illustrate multiple overprinting relationships for the hydrothermal system in the Tchaikazan River area. 104 5.4.1 Hub Early, high-temperature alteration mineral phases consist of biotite ± magnetite ± quartz alteration. Mineralization is inferred to have occurred within the high-temperature alteration zones. Propylitic alteration could have been synchronous with this high temperature alteration, as the intrusion of a pluton at depth creates propylitic alteration distal to the high-temperature core of the porphyry system. Propylitic alteration continues as long as the magmatic system exists. With the waxing of magmatic input propylitic the footprint of the propylitic mineral assemblages is extended closer to the causative intrusion. This leads to the early, high temperature, pervasive biotite ± magnetite alteration being locally overprinted by chiorite-epidote alteration. Texturally, this is observed as shreddy chlorite, replacing biotite in the hydrothermal breccia and Hub diorite. Silicification and sericite alteration are locally developed at the Hub and appear to post-date biotite ± magnetite alteration, inferred by the cross-cutting sericite alteration in the feldspar hornblende dykes. Veining at the Hub porphyry is outlined in Table 5.2. Quartz veins and quartz ± sulphide veins cross-cut the Hub diorite and hydrothermal breccia. Veining is locally texturally destructive affecting the groundmass of the Hub diorite. Quartz veins commonly have sericite haloes. 5.4.2 Charlie-Northwest Copper Discrete areas of intense propylitic alteration, epidote alteration, kaolinite-dickite, and quartz-diaspore alteration characterize hydrothermal alteration in the Charlie-Northwest Copper area. These areas are spatially associated with the Northwest Copper pluton, Ravioli Ridge, and the inferred position of the Northwest Copper thrust faults (Figure 5.1). Advanced argillic alteration consists of fine-grained alumino-silicates that appear to be superimposed over other, earlier alteration types. Weak background chlorite ± epidote ± calcite ± albite ± quartz alteration is observed proximal to the sericite altered locations. Propylitic alteration, comprising chlorite epidote-calcite ± albite ± quartz affects much of the andesite on the topographic highs of Charlie and Northwest Copper (Figure 5.1). Cross-cutting relationships are observed in veins from the Tchaikazan River area and are outlined in Table 5.2. Shallow-moderately dipping dogtooth quartz ± sulphide veins cross-cut earlier, steep carbonate veins in the Charlie and Northwest Copper area (Figure 5.1OA). The same generation of shallow-moderately dipping dogtooth quartz veins is observed to cross-cut epidote veins ± quartz alteration haloes (Figure 5.1 OB). This relationship is observed often in the 105 Charlie-Northwest Copper area. Figure 5.1 0C illustrates the cross-cutting relationship between quartz and epidote veining, with the epidote vein offset several centimeters. Figure 5.1 OD shows a planar massive calcite vein, the cross-cutting relationships of this vein-type are unknown in the Tchaikazan River area. These veins typically show intense chlorite-epidote alteration haloes. Quartz and carbonate veins are locally developed in the Northwest Copper area, their cross cutting relationships to other vein-types was not observed, although they typically dip steeply to the northwest, rarely contain suiphide mineralization, and generally lack significant alteration selvages. 5.5 ORE ASSEMBLAGES The distribution of metals is compiled from rock samples from the three main areas of study and interpreted geological and mineralization/alteration mapping. Sulphide minerals precipitate from hydrothermal solution when their constituent metals and sulphide are more stable residing in the solid than in aqueous solution (Reed et al., 2006). In the porphyry environment sulphides may precipitate owing to an increase in pH, which liberates suiphide from H2S or HS Cooling of the hydrothermal system is another way through which sulphides can precipitate, where intrinsic suiphide mineral stability is greater (Reed et a!., 2006). The spatial and temporal distribution of veins and associated hydrothermal alteration is based on cross-cutting relationships and mineral overprinting textures. This distribution and spatial association of metals, such as Cu, Mo, and Pb, with respect to the alteration styles that they accompany are described below. 5.5.1 Hub The Hub porphyry deposit displays styles of mineralization that are typically attributed to porphyry hydrothermal-magmatic systems. Stockwork veins/veinlets and the hydrothermal breccia host the bulk of Cu (± Mo) mineralization. Stockwork veining has been recognized in other porphyry studies and used as vector to porphyry-style mineralization (Gustafson & Hunt, 1975; Seedorf et a!., 2005; Cannell et a!., 2005). Table 5.2 documents the vein paragenesis, alteration, and associated suiphides of the Hub porphyry deposit. In porphyry deposits, Cu (± Mo, Au) mineralization typically occurs as zones arranged around a causative intrusion (Lowell and Guilbert, 1970; Seedorf et al., 2005). The Hub porphyry deposit exhibits this trait. Copper (± Mo) minerals, including chalcopyrite and molybdenite, occur as fine disseminated grains and as coarse crystals in the centre-line of quartz stockwork veining. Biotite ± magnetite alteration often corresponds to the metal anomalies at the 106 Hub. Therefore it is inferred that the biotite ± magnetite alteration and brecciation were important in the metal endowment of the Hub showing. Magnetite-biotite (locally chlorite) veins are the earliest vein generation observed at the Hub porphyry (Figure 5.11 A and B). Locally, they are found in diorite clasts in the hydrothermal breccia but more typically magnetite is fine-grained in veinlets associated with quartz, chalcopyrite, and pyrite (Figure 5.11 C). Quartz-chalcopyrite-pyrite veins have sericite-chiorite alteration selvages (up to 5 mm thick) (Figure 5.11 D). Chalcopyrite, and chalcopyrite-pyrite stringers cross-cut the Hub diorite and they are cross-cut by thin (up to 10 mm) sulphide-poor quartz veins, which lack an alteration selvage (Figure 5.11 E). Steeply dipping (100 to core axis), fine anhydrite veinlets are observed to cross-cut the hydrothermal breccia. Quartz ± anhydrite ± pyrite-sericite veins are locally developed and displace the fine anhydrite veinlets in drill core (typically 50-60 0 to the core axis). The terminal vein-stage, thick (up to 30 mm), sulphide-poor quartz veins are observed to cut quartz ± anhydrite-chalcopyrite-pyrite veins and all other vein- types when observed. The Hub porphyry deposit provides examples of a variety of sulphide mineral textures (Figure 5.12). Chalcopyrite is the most commonly observed Cu sulphide mineral (Figure 5.1 2A) and occurs as a centre-fill to quartz veins, as chalcopyrite veinlets (Figure 5.12B-D), disseminated, and as a void-filling cement (Figure 5.1 2E). Molybdenite is locally developed on the margins of quartz-anhydrite veins, and as a fracture-coating (Figure 5.1 2F). Disseminated suiphides are common in the Hub porphyry deposit; euhedral chalcopyrite and pyrite grains are readily observed in hand specimen and thin section (Figure 5. 14A). Chalcopyrite-pyrite ± quartz is a common cement to the hydrothermal breccia (Figure 5.1 3B and C). Magnetite is typically developed throughout the hydrothermal breccia (Figure 5.13D). Galena is rare is in the Hub porphyry deposit and was identified using back-scattered SEM images (Figure 5. 13E). 5.5.2 Charlie-Northwest Copper The Charlie-Northwest Copper area hosts many different vein—types, ore assemblages, and hydrothermal alteration assemblages, many of which are not observed or developed within the Hub porphyry deposit. Table 5.3 indicates vein paragenesis, alteration, and mineralization observed in the Charlie-Northwest Copper area. Vein assemblages can be divided into those that contain ore minerals and those that are barren. Copper mineralization in the Charlie- Northwest Copper is evident as disseminated grains and veinlets and Cu minerals observed include chalcopyrite, chalcocite, native copper, and rare bornite (Figures 5.14 and 5.15). Quartz-chalcopyrite-pyrite ± galena veins are spatially restricted to the Charlie area. 107 Chalcopyrite, pyrite, and galena are typically coarse-grained, up to 3 mm in size and distributed throughout the quartz veins (Figure 5.1 5A and B). Quartz-pyrite veins are locally developed on the flanks of the Charlie ridge. Pyrite is typically coarse-grained and in the centre of massive and combtooth-textured quartz veins. Sericite alteration selvages are locally developed with this vein-type. Shallowly dipping, native Cu-bearing quartz veins are locally developed in the Northwest Copper area. They are spatially restricted to the Powell Creek Formation non-massive facies. Disseminated and vein-style textured native Cu was observed (Figure 5.1 5C-E). Quartz-calcite chalcocite veins are typified by malachite staining in outcrop. Chalcocite is typically fine-grained and in veinlets. Epidote-quartz-magnetite-chalcopyrite-pyrite veins are spatially associated with the Northwest Copper pluton in the southwest of the study area. Chalcopyrite and pyrite occur as coarse disseminated grains and veinlets. Magnetite in the veins is typically fine-grained and intergrown with quartz. Disseminated and veinlet tetrahedrite is found in association with quartz-diaspore alteration in the Ravioli ridge area (Figure 5.1). In this location tetrahedrite is abundant as coarse, anhedral grains, up to 10 mm in size surrounded by a matrix comprising microcrystalline quartz and diaspore. 5.6 AGE OF MINERALIZATION 5.6.1 Hub The paragenetic sequence of mineralization is outlined in Figure 5.16. The earliest mineralized veins at the Hub porphyry deposit are magnetite-biotite veins (Figure 5.16A); these are synchronous with quartz-magnetite ± chalcopyrite veins and cross-cut the hydrothermal breccia. Quartz-magnetite ± chalcopyrite veins are cross-cut by quartz-magnetite ± chalcopyrite ± pyrite veins and are therefore inferred to have formed synchronously, or soon after each other. Quartz ± molybdenite ± pyrite ± chalcopyrite veinlets cross-cut and therefore post-date quartz-magnetite ± chalcopyrite ± pyrite veinlets. Pyrite ± chalcopyrite stringers cross-cut quartz-sulphide bearing veins. Quartz ± anhydrite-pyrite-sericite veins are inferred to be late in the paragenetic sequence as they lack significant Cu-Mo mineralization and are often accompanied by intense sericite alteration of the host rock. Quartz-pyrite-chalcopyrite veins are included within clasts of the breccia. Therefore, a fluid pulse responsible for quartz-chalcopyrite-pyrite veins is cut by brecciation. Mineralization is locally developed in the Hub diorite, which has a U-Pb zircon 108 emplacement age of 81.19 ± 0.78 Ma, and a late-stage (magmatic), post-mineralization feldspar homblende dyke yielded a homblende Ar-Ar age of 69.9 ± 1.5 Ma. Therefore given the sulphide and vein paragenesis presented above, it is inferred that Cu-Mo mineralization occurred between —P81 and —‘70 Ma. 5.6.2. Charlie-Northwest Copper Cross-cutting relationships between mineralized veins in the Charlie-Northwest Copper area were often difficult to observe, given their spatially restricted distribution. They are typically restricted to the Charlie ridge. Chalcopyrite was observed in a dyke at the Charlie showing (sample O6LH-GO1) which yielded a U-Pb zircon age of 76.41 ± 0.98 Ma. The similar composition, age, spatial association, and sulphide assemblage of this dyke to that at the Hub suggests that magmatism and mineralization at these two localities may be temporally linked. There is no temporal link between intrusions at Northwest Copper with either the Charlie showing or Hub porphyry deposit. Therefore the veining observed in the Charlie-Northwest Copper may represent multiple phases. Similar vein compositions are observed proximal to the Northwest Copper pluton and at the Hub porphyry deposit. At both locations quartz-magnetite-chalcopyrite ± pyrite veins are locally developed. Given the distance between these two locations (5-6 km), their paragenetic relationship cannot be detennined by field relationships. Stable isotope evidence suggests a temperature of --500°C (see section 5.7) for quartz-magnetite-chalcopyrite veins. This high- temperature suggests these veins are related to the emplacement of the Northwest Copper pluton at 57 Ma and are formed from magmatic-derived fluids. This young age for the Northwest Copper pluton compared to the 80-70 Ma age proposed for the Hub porphyry system indicates that veining in the Northwest Copper area may represent a separate temporal event and the development of multiple mineralizing magmatic-hydrothermal systems. The paragenetic evolution of the Charlie-Northwest Copper mineralized veins cannot be accurately discriminated owing to the lack of cross-cutting relationships between individual mineralized veins. Quartz chalcopyrite-pyrite ± galena veins in the Charlie area are inferred to be high temperature and likely early in the evolution of the mineralizing system in the Charlie-Northwest Copper area (Figure 5.16B). Disseminated and vein tetrahedrite was locally observed in a breccia with quartz-diaspore alteration. This veining is inferred to cross-cut propylitic alteration. Quartz and diaspore are known to occur within the advanced argillic alteration assemblages of porphyry deposits and high-sulphidation epithermal deposits (Arribas et al., 1995). The mineral assemblage observed in 109 this outcrop on Ravioli Ridge is similar to those reported from the Lepanto high-suiphidation epithermal deposit; where hypogene advanced argillic alteration, and high-sulphidation-state minerals, such as the Cu-sulfosalt mineral tetrahedrite are reported (Arribas et al., 1995). Native Cu and chalcocite veins were spatially restricted to the Powell Creek Formation non-massive facies in the Northwest Copper area and are typically associated with dense calcite veining. Figure 5.1 5D illustrates the form of these thin (<10 mm thick) native Cu stringers, often accompanied by Cu carbonate minerals, such as malachite (Figure 5.1 5C-E). When viewed in reflected light (Figure 5.1 SE) the native Cu is typically coarse-grained and often utilizes pre existing contacts or fractures between resedimented volcanic units. 5.7 FLUID INCLUSION MICROTHERMOMETRY Fluid inclusions have been widely applied in research into porphyry ore deposits (Rusk et al., 2008). Porphyry deposits form where magmatic-hydrothermal fluids permeate intrusive igneous rocks. These fluids form a stockwork of quartz and quartz-sulphide veins. The distribution and types of fluid inclusions were analyzed from selected quartz vein samples from the study area in order to learn more about the temperature, pressure, and compositional evolution of the hydrothermal fluids that formed the mineral showings in the Tchaikazan River area. 5.7.1 Sampling and analytical techniques A total of 5 doubly polished thin sections of quartz vein material were chosen after petrographic analysis. Selected veins typically host sulphide mineralization and are coarse grained and massive in texture. The fluid inclusions within were variable in type, distribution pattern, homogenization temperature, phase content, and volume percent vapor; a pattern common in other porphyry copper deposits (Wilkinson, 2001). Complete microthermometric results are presented in Appendix III. NaC1 equivalent salinities were calculated using the final melting temperature (Tm (ice)) of ice in liquid-vapor inclusions. Petrography was employed and inclusions were identified and classified according to schemes presented in Samson et al. (2003). 5.7.2 Description of fluid inclusions from the Hub porphyry deposit Unfortunately, primary fluid inclusion assemblages could not be identified in samples of quartz veins taken from the Hub porphyry. The dense concentration and small size of the fluid inclusions contributed to the lack of the correct inclusions necessary for microthermometric analysis. Hence, no microthermometric data is available for the Hub porphyry deposit. 110 5.7.3 Description of fluid inclusions from the Charlie-Northwest Copper area Microthermometric studies were performed on three quartz veins from the Charlie- Northwest Copper area (Figure 5.17). The aim of these studies was to approximate pressure- temperature-compositional (P-T-X) conditions of the magmatic-hydrothermal system. Veins were chosen that contained chalcopyrite ± pyrite mineralization. Quartz grains vary in size from 0.1 to 10 mm in length, with larger inclusions hosted by larger grains. Some bias towards larger inclusions was necessary due to microscopic limitations. Smaller grains generally host abundant fluid inclusions, but the density is too high to allow identification of individual inclusions that are appropriate for microthennometric analysis. Three types of inclusion were identified in the Charlie-Northwest Copper sainples: (1) Small, monophase liquid inclusions are the most abundant inclusion-type, and are interpreted as secondary in occurrence. They are therefore unsuitable for microthermometry. (2) Liquid-Vapor (L-V) inclusions are common in the vein samples studied and are assumed to comprise H20 and NaCI. They are typically sub-rounded and vary in size from 5- 40!Im. Vapor content varies from 15 to 40 volume percent. Tm (ice) measurements for ice correspond to salinities between 1.7 and 20.3 wt. % NaCl. These L-V fluid inclusions always homogenized into the liquid phases with Th(total) occurring between 190 and 230°C. (3) Vapor-rich inclusions (V>50%) are less common in the samples studied. They are typically sub-rounded and dominated by a large vapor bubble. Primary fluid inclusions (P) were rarely developed or too small to readily be analyzed (Figure 5.17) which is a common problem in samples from the porphyry environment. Bias towards larger inclusions was necessary. Growth zones in quartz crystals are the usual host to these primary inclusions (Figure 5.1 7A). These inclusions were however, too small for analysis (<Sjim). The inclusions are liquid-rich, two-phase (L + V), sub-spherical and lack secondary daughter minerals. A single, small vapor phase/bubble typically accounts for less than 15% of the inclusion (maximum of 40%). Secondary (S) and pseudosecondary (PS) fluid inclusions are abundant (Figure 5.1 7B), typically small, and cross-cut crystal boundaries. Measurements of Tm 111 (ice) for the liquid-rich, halite-undersaturated inclusions range between —0.8 and —3.4°C and homogenize at temperatures between 169 and 193°C (Table 5.6). The inclusions measured trapped low-salinity; dilute fluids under conditions between 190 and 23 0°C. Fluid inclusions proved inconclusive for generating a palaeodepth. The minimum temperature of 169°C represents the minimum temperature for vein-forming fluid within the Charlie-Northwest Copper area. However, secondary inclusions were measured so this temperature does not represent the first phase of fluid formation in these veins, but a later fluid in the evolution of the magmatic-hydrothermal system. Despite the small data set, some distinct trends exist: (1) all inclusions measured in the quartz veins homogenized above 169°C; and (2) most inclusions had similar liquid to vapour ratios. 5.7.4 Discussion The lack of fluid inclusion assemblages that could be definitely identified as primary assemblages creates difficulties in estimating temperature of entrapment and possible palaeodepth. Many authors cite boiling/phase separation in magmatic-hydrothennal systems as a primary mechanism for mobilization and concentration of metals in the formation of ore deposits (Drummond and Ohmoto, 1985). The coexistence of liquid-rich and vapor-rich fluid inclusions is the most common evidence cited for the presence of boiling in a system. The samples studied therefore do not show unequivocal evidence for boiling of the hydrothermal system. There is a lack of high temperature and high salinity fluid inclusions from the veins studied from within the Tchaikazan River area. The lack of high temperature fluid inclusions may suggest that the high temperature fluid inclusions were previously destroyed or overprinted by retrograde processes and what we are seeing now is evidence of secondary or pseudosecondary fluids evolving post-mineralization. Low salinity fluids are recorded in the Butte porphyry system (Rusk et al., 2004). Rusk et al., (2004) infer low-salinity fluids are formed from the unmixing of a parental low salinity magmatic fluid, however the fluid inclusion at Butte represent samples of a single-phase parental magma-derived aqueous fluid. Such single phase fluid inclusions were not observed within the samples from the Tchaikazan River area. 5.8 STABLE ISOTOPES Of the large number of naturally occurring stable isotopes, hydrogen, carbon, and oxygen have the necessary properties to be of use in determining the temperature of co-existing mineral phases, and the potential source of hydrothermal fluids. Determining the carbon and oxygen 112 isotopic values of carbonates can provide information regarding fluid sources, and may provide information into the formation of the vein material (Rollinson, 1993). Most carbon in nature is made up of ‘2C (98.9%), with the rest mainly consisting of ‘3C (Browniow, 1996). Carbon in hydrothermal fluids can be present in a number of forms, but occurs primarily as CO2 or CH4. There are large isotopic fractionations between reduced and oxidized carbon species and the abundance of these species in solution is largely a function of temperature, pH, and 102 (Rye and Ohmoto, 1974; Rye, 1993). Thus, for meaningful interpretation, carbon isotope data must be tied to detailed geologic studies. Carbonate minerals can precipitate from fluids containing oxidized carbon species, including C02,H2C03,HC03, and C032. Carbon may be derived from a magmatic source, oxidation of reduced carbon reservoirs, or by leaching of sedimentary carbonates. The distinctive 6’3C values of each of these sources, aids the determination of the CO2 source (Rollinson, 1993). The complex nature of fractionation processes can hinder the interpretation of the source to a particular source region, e.g., the mixing of two diverse reservoirs, sedimentary organic carbon (-26 to -38%o) and seawater (-O%o), can generate &3C values in the mantle range (-2 to -8%o) (Rollinson, 1993). Oxygen is the most abundant element of earth, it occurs in gaseous, liquid, and solid compounds. Oxygen has three stable isotopes with the following abundances: 160 (99.763%); ‘0 (0.0375%); and (0.1995%) (Hoefs, 2004). Oxygen isotopic composition, expressed as 180 is a measure of the ratio of 180 (0.1995% natural abundance) to 160 (99.763%) in the sample as it deviates away from the oxygen isotope standard (VSMOW — Vienna standard mean ocean water). The oxygen isotope composition of a rock depends on the 180 contents of the constituent minerals and the mineral proportions. Oxygen isotope ratio analysis provides a tool for the study of water/rock interaction. Shifting oxygen isotope ratios of the rock and/or fluid away from their initial values indicate that their compositions are not in equilibrium (Hoefs, 2004). Calculation of the 6’0 of the water in equilibrium with hydrothermal carbonate is difficult owing to the lack of precise formation temperatures, which are necessary given the temperature dependency of the oxygen isotope fractionation (O’Neil et al., 1969). The ambient temperature of the hydrothermal system must have been greater 1 20°C (the closure temperature of apatite fission track). The age-elevation plot and the ZFT date suggest a syn-mineralization depth at 5-6 km depth. Therefore, temperatures >120°C are considered to be geologically realistic for veins formed within the Tchaikazan River hydrothermal system, and fractionation temperatures below this range are not considered. 113 5.8.1 Sampling and analytical techniques Carbonate stable isotope analyses Calcite cement from carbonate veins have been analyzed for their O’O and O’3C isotopes. Janet Gabites at the University of British Columbia (PCIGR) analyzed powdered carbonate vein samples, using the gas bench and a Delta P1usXL mass spectrometer in continuous flow mode. Samples were acidified with 99% phosphoric acid in helium flushed sealed vials, and the headspace gas was measured in a helium flow. Corrections for fractionation were done through repeat analyses of UBC internal carbonate standards BN 13, BN 83-2, and H6M. These have been calibrated against NBS international standards NBS 18 and 19. The 6’3C and 6180 values were corrected to VPBD and VSMOW based on an average of multiple analyses of NBS standards 18 and 19. Oxygen and Hydrogen stable isotope analyses Oxygen isotopic analysis of 12 quartz vein samples, 2 magnetite vein samples, and a whole rock sample were performed by Kerry Klassen at Queen’s University in July and November 2008. Analyses were carried out using a Bromine Pentaflouride extraction line and a Finnigan Mat 253 Mass spectrometer. 6180 and 3D results have been corrected to VSMOW. The equivalent fluid values of 6180 and 613C were calculated using equations from Ohmoto and Rye (1979) and O’Neil et al. (1969). Fractionation corrections were calculated at 500°C and 300°C for quartz veins, 200°C for kaolinite, and 400°C for magnetite and epidote veins. These temperatures are estimated to correspond to the temperatures presented in porphyry literature (Cooke et at., 2005; Seedorfet at., 2005; Gustafson & Hunt, 1975). 5.8.2 The Hub porphyry deposit Oxygen stable isotope analysis of quartz veins A total of 6 quartz veins were sampled for analysis using 180 isotopes. Summary statistics of 0 isotope results are presented in Table 5.4. These veins typically contain suiphides (chalcopyrite and pyrite) and have grey sericite or sericite-chiorite haloes. Similar sericite and sericite-chlorite haloes are known to form around veins at temperatures of 400-450°C in the Butte porphyry system (Rusk et at., 2004) and sericite alteration in the Island Copper deposit occurred at temperatures of 360-420°C (Arancibia and Clark, 1996). Hence, a range of fractionation temperatures of 350°C, 450°C, and 500°C are used in fractionation calculations for these quartz veins. Quartz veins from the Hub displayed 0180 (SMOW) rock values ranging from +6.5 to 114 +12.2%o, averaging 8.3%o. Quartz mineral data has been used to calculate 6’80H20 in order to assess the source and formation processes of oxygen at temperatures of ‘500°C and 350°C. Figure 5.18 shows &80 (%o) VSMOW values for selected quartz veins in the study area. Oxygen stable isotope analysis of quartz-magnetite A pair of quartz-magnetite mineral separates were drilled from a single vein at the Hub porphyry deposit (Samples 07-LH-Hub-q and O7LH-Hub-m) (Table 5.4). The samples were analyzed to constrain the temperature of the fluids responsible for the quartz-magnetite ore- forming stage at the Hub porphyry. Unfortunately the samples yielded a fractionation factor that was too low to generate a feasible temperature for quartz-magnetite fractionation geothermometry. However, these veins are spatially related to biotite ± magnetite ± quartz alteration. At the Island Copper porphyry Cu-Au-Mo deposit, B.C., magnetite-rich alteration is inferred to occur at temperatures 500°C (Arancibia and Clark, 1996). Oxygen stable isotope analysis of magnetite Two powdered magnetite samples were taken from veins within the Hub porphyry for analysis using 6180 stable isotopes (Samples O6LH-Hub-09m and O7LH-HLJB-m). These samples yielded values of 3.7%o and 4.7%o. A temperature of 500°C was used to calculate equivalent fluid values for magnetite. This temperature is similar to those documented for magnetite-bearing veins in other porphyry deposits (Arancibia and Clark, 1996). Calculated values for the fluid in equilibrium with magnetite were 9. 8%o and 10. 8%o using the magnetite water equilibrium equation of Zheng (1991). 5.8.3 Charlie-Northwest Copper Carbon stable isotope analysis of calcite veins A total of 12 samples of vein calcite were sampled from the Charlie-Northwest Copper area (Figure 5.1 9A). These veins were typically massive calcite-only veins or quartz veins with a calcite centre-fill. Uncorrected Ô’3C and 8180 values are shown in Table 5.5. Calculated Ô’3C fluid values range from -1.2 to -9.5%o, and 8180 fluid values range from +6.5 to +l2.2%o. Fractionation corrections for equivalent 6180 and 6’3H20isotopic values at 300°C were calculated using equations from Beaudoin and Therrien (2008). The majority of the powdered vein calcite samples plot within the magmatic water field (Sharp, 2006; Rollinson, 1993) (Figure 5.19B), suggesting that the veins were precipitated from 115 dominantly magmatic fluids. However, 3 vein samples (2 from Northwest Copper) fall outside of this field, displaying higher values of &80. A powdered vein from Northwest Copper also displays a higher ö’3C value. These anomalous values may be explained by contamination from other minerals during separation for analysis, which is feasible given the small-scale of the areas drilled. However, Kerrich and Wyman (1990) stated that the same signature could be created by leaching of carbonate host rocks or oxidation of free carbon, and do not necessarily indicate that the CO2 is of mantle or magmatic origin. Therefore the C and 0 isotope data obtained in this study do not clearly discriminate the sources of the fluid. Oxygen stable isotope analysis of quartz veins Twenty samples of powdered quartz were drilled from vein material sampled from the Charlie-Northwest Copper area and submitted for analysis of 6180. Fractionation temperatures of greater than 200°C are used in this study. Temperatures of 3 00°C are inferred to be significantly higher than the ambient temperature of the host rocks. Magmatic bodies create thermally driven convection cells with fluid temperatures greater than that of the inferred ambient temperature (<200°C). Therefore a temperature of 3 00°C represents a conservative, geologically realistic estimate. Values for 6180 range from 7.1 to l5.5%o, with an average of 11.1%o. Complete data for 6180 of quartz samples is shown in Table 5.4. Fluid values were calculated for quartz veins at temperatures of 500°C and 300°C using equations from Matsushima et al. (1979). 6180 isotopic evidence suggests that the quartz vein-forming fluid shows a variation in isotopic signatures (Figure 5.18). The majority fall into the realm of meteoric water, with a few exceptions, which lie within the magmatic water field. Oxygen stable isotope analysis of quartz-magnetite veins A pair of quartz-magnetite mineral separates were analyzed for their oxygen isotopic composition in order to place a constraint on the possible temperature of formation of the minerals. The quartz-magnetite is inferred to have formed in equilibrium due to intergrowth mineral vein textures. Quartz-magnetite pairs from the samples 07-LH-230 generated 6180 (VSMOW)(quap.zmagnetite) values of 1 O.8%o. This fractionation factor corresponds to an equilibrium temperature of 490°C using equations from Chiba et al. (1989) (Figure 5.20A). 116 Hydrogen and Oxygen stable analysis of kaolinite alteration A sample of a kaolinite mineral sample from the Northwest Copper advanced argillic alteration zone yielded a 6180 rock value of 6.6%o (VSMOW), and a 6D rock value of -113%o (VSMOW) (Table 5.4). The corrected 6’80H20 value was calculated using equations from Lambert and Epstein (1980). This sample was analyzed in order to constrain the likely source of the fluids responsible for the pervasive kaolinite- dominated alteration on the western flank of Ravioli Ridge. Unfortunately the values plot well outside of the fields of magmatic or meteoric fonnation waters, indicating either that the sample may have been impure, or several sources are responsible for the kaolinite sample. 5.8.4 Discussion and Interpretation Fractionation of mineral species is highly temperature dependant (Figure 5.18). At 500°C quartz veins from the Hub display &80H20 values that can be attributed to a magmatic source. However, a shift in fractionation temperature to a minimum of 300°C creates a decrease in isotopic fluid values, indicating deposition from a dominantly meteoric fluid source. Using the spatial relationship of the veins to high temperature biotite-magnetite alteration and their sericite haloes, it is inferred that temperatures of 400-450°C are more realistic. At such temperatures a transitional source between meteoric and magmatic fluids is observed. The veins observed at observed at Charlie-Northwest Copper, are different than those at the Hub, both in terms of host rock, alteration, and mineralization. Temperatures >250°C are used in calculation of fluid values for these veins. The veins at Charlie-Northwest Copper are inferred to be somewhat lower in temperature to those observed at the Hub. There is no spatial association between veins in the Charlie-Northwest Copper area and high-temperature K-silicate alteration. At 400°C those quartz veins with chalcopyrite, galena, and pyrite from the Charlie area plot within the magmatic water field (Figure 5.18). These are of contrast to several of the quartz veins sampled from the Charlie-Northwest Copper area, which show a more depleted 8’0uo signature, indicating that meteoric water may have been involved in their formation (Figure 5.18). Samples of calcite veins were analyzed using 6’80H20 and 613C02 values (Figure 5.19B). 6180 and 8’3C calcite trends from the Tchaikazan River area are mostly consistent with precipitation from a magmatic source. Highly positive values indicate that mixing with meteoric fluids was not a likely precipitation mechanism, because meteoric water has more negative 6180 values (Cambell and Larson, 1998). Figure 5.18 shows an array of data points that define a broad zone, the scatter in the data points means that it is not possible to discriminate between calcite 117 precipitation from progressively decreasing fluid/rock ratios and a change in temperature (decrease) or calcite precipitation overprinting a more evolved fluid overprinting earlier-formed hydrothermal calcite. In general, 18O values for the Tchaikazan River area show a clustering of values around 6-896o for quartz veins from the Hub. Quartz-sulphide veins sampled from the Charlie area are in good agreement with ö180 values of —1 O%o. Calculatedö18Oiuo values from Northwest Copper quartz veins display the greatest range, the lowest at 4.896o (Sample O7LH-213). There is a clustering of veins showing magmatic 6180 values (6- 1 O%o), with a few with more enriched values of >12%o. Pairs of quartz and calcite intergrown from veins yielded fractionation factors too small to yield a reasonable temperature for the formation of the veins given the geological framework. The difference in 6180 likely indicates different fluid formation temperatures, and several pulses of hydrothermal fluid through a single vein locality. 118 — Sense of movement o 500 l000m Figure 5.1: Schematic map of observed hydrothermal mineral assemblages in the Tchaikazan River area; compiled data from mineral mapping in addition to SWI R analyses. 119 Legend to hydrothermal alteration mineral assemblages Epidote (ca) alteration Biotite ± magnetite alteration y y Thrust faultPervasive and vein-hosted Propylitic alteration (index 1 2) E1 Quartz-diaspore alteration chlorite, calcite, albite, ± epidote Propylitic alteration (index 3) Epidote veining, pervasive chlorite Sericite alteration (phyllic) carbonate alteration Kaolinite-dickite-illite alteration — — — — Normal fault E1 Silicification Strike-slip fault Unknown/or background regional metamorphic grade E1 Undifferentiated valley fill High density vening Table 5.1: A summary of hydrothermal alteration and mineralization sequences for the Tchaikazan River study area, compiled from field and petrographic observations. Transitional LateEarly Least (High temperature) (Feldspar (Feldspardestructive) destructive)Altered Minerals Bio-Mag (K- I Chi-Epi- IQtz-mag Qtz-seri Di-kao I Qtz-diafdpr) Aib Hornblende Bio, Chi Bio Seri, Chio Chlo, Ep, Seri, ChloCal, Aib Biotite Bio, Chl Mag Chi, Sen Qtz-dia, Ill, Kao,Plagioclase K-fdspr (rare) chlo Pig, Sen Chi, Sen Dkt, Mnt. Abundant AbundantMag. Hem. Mag Hem. Hem. >40% >80% Diss. Suiphides Dis Cpy, moly Cpy, Pyr Mainly Py, Pyr Tetra. moly, py, some Cpy minor bn Veins and Qtz-mag, Qtz- Qtz-py, Epi, Cpy, Diss. Mai,Qtz-Cpy Pyr Rarely Py veinlets Cpy-moly Cal, Py azu py Primary DestroyedPreserved rock and Destroyed Somewhat Destroyed,Destroyed mostly mostly preserved brecciatedtexture breccia 4 CHARLIE NORTHWEST COPPER HUB Centre of Magmatic-hydrothermal system Notes: Mineral abbreviations: Bio-Biotite, Chi-Chiorite, Epi-Epidote, Cal-Calcite, Seri-Sericite, Mag-Magnetite, Plg-Plagioclase, Ill-Illite, Kao-Kaolinite, Dkt-Dickite, Mnt-Montmorillonite, Hem-Hematite, Dia-Diaspore, Tetra-Tetrahedrite, Mal-Malachite, Azu-Azurite, Qtz-Quartz, Pyr-Pyrite, Cpy-Chaicopyrite, Moly-Molybdenite, Bn-Bornite. 120 Intensely illite-altered Monzonite is not altered by magnetite - biotite. Partial sericite, chlorite, epidote alteration only Pervasive feldspar destructive alteration - sericite abundant chlorite after hornblende and up to 10% disseminated pyrite feldspar-hornblende dyke, similar to phase to the southwest /90 Abundant secondary biotite, up to ‘-5% dissminated magnetite. Chalcopyrite, pyrite and magnetite in quartz veins and as small stringers 45 19 14 Sporadic outcrop; brecciation common Epidote observed I Ii I II I I 31 28 20 27 4— Secondary biotite dominant in primary mafic igneous mineral sites 2.5cm=50m Strong biotite-magnetite alteration: often accompanied by feldspar growth. 1— 12 01 18E / Intense magnetite alteration of Hub diorite, often accompanied by a brecciated texture 47 —. 54 zp B Key to pervasive alteration Sericite-chlorite Chlorite-epidote Biotite-magnetite silicification 31 sample numberi.e O6LHhub-31 Figure 5.2: Map of the Hub porphyry trenches. Pervasive hydrothermal alteration is mapped, including sericite-chlorite, chlorite-epidote and biotite-magnetite alteration (Letters refer to the position of photographs from Figure 5.3 - comparison of drill core and outcrop. Drill Core Outcrop Figure 5.3: Comparison of features observed from drill core and surface outcrop within the biotite magnetite cemented hydrothermal breccia. A) Hole 08TSK-02, depth= 100.2 m. Contact between the Hub diorite and the hydrothermal breccia. B) Same relationship as observed in A, taken from surficial trenches at the Hub showing. C) Hole Q8TSK-02, depth = 256 m. Clastic breccia, with granodiorite and quartz sulphide veining. D) Same clastic relationship as seen in D, large sub-rounded clast of altered diorite. E) Hole O8TSK-06, depth =89 m. Clastic breccia, with andesite and vein quartz clasts. F) Same textural and compositional relationship as observed in drill core (F). 122 ic 13 = Quartz after plagioclase RE = Rock Elour ---- = Clast margin EP = Eine-granied porphyry = Qt vein QV = Quartz Vein = Suiphide Figure 5.4: Hand specimen slab from the Hub hydrothermal breccia . A) Photograph of hand specimen, showing the pervasive biotite ± magnetite alteration giving a black-coloured rock in hand specimen. B) Schematic diagram with textural features highlighted - truncated quartz veining, sulfide mineralization, pervasive K-silicate alteration, and variation in clast texture, roundness and composition. I 123 Figure 5.5: Photoplate of the biotite - magnetite alteration in the Hub porphyry system. A) Fine-grained biotite - magnetite infilling as cement. B) Strongly biotite-altered clast in hydrothermal breccia (left), in contact with Hub diorite clast (right). C) Secondary biotite pseudomorphing hornblende phenocryst in plane polarized light. D) Fine, stubby secondary biotite replacing igneous biotite in the Hub diorite. 124 Figure 5.6: Photoplate of the styles of alteration at the Hub porphyry deposit. A) Partial sericite alteration of feldspars in the Hub diorite. B) Pervaisve sericite alteration of the feldspar- hornblende dyke. C) Feldspar - hornblende dyke, with significant pyrite content and mafic xenolith. D) Chlorite - epidote alteration of biotite in the Hub diorite. E) Chlorite-altered hornblende, with secondary biotite replacing chlorite. 125 Figure 5. 7: Photoplate showing the styles of hydrothermal alteration in the Charlie-Northwest Copper area. A) Thin section in plane polarized light, showing a quartz-epidote vein in sericite-epidote altered andesite. B) Thin section in plane polarized light, showing intense epidote replacement of the igneous groundmass. C) Intense epidote veining in the Powell Creek Formation coherent facies, D) Thin section of garnet and epidote in crossed polars, taken from a location near the Northwest Copper pluton. E) Kaolinite-dickite ± microcystalline quartz alteration of the Powell Creek Formation, in crossed polars. F) Thin section for the quartz-diaspore alteration, showing the infilling of the matrix by diaspore and quartz-altered clasts. 126 Figure 5.8: Photoplate of advanced argillic alteration on the western flank of Ravioli ridge. A) Field photograph taken facing south with a view of the yellow, earthy alteration zone. B) Field monkey standing atop the intense clay alteration (photo courtesy of Scott Blevings). C) Inferred position of normal fault with intense clay-dominated alteration. D) Looking down on exposed fault plane, with intense clay alteration below. 127 • •1 Figure 5.9: A) Photograph of a hand sample slab from the quartz-diaspore alteration on Ravioli ridge. B) Schematic sketch highlighting the main textural and compositional features, plus tetrahedrite mineralization. cmO 2 4 I_I 128 Table 5.2- Summary of Vein Paragenesis, Alteration and Mineralization for the Hub porphyry deposit Vein C U’ Closest vein descriptionparagentic Vein Name Mineralogy Features Abundance Associated intrusions, alteration, suiphides rosscu ing from Cannell et al., 2005 and tage ( annCu Mo VA relationships et aL, 2005)sequence Gustafson and Hunt, 1975. Quartz stringers Quartz (minor chlorite) Thin (<3 mm), abundant. Fragments of these veins are - - C Hub Dionte Crosscut and offset by sub-vertical Crosscuts the Hub Earliest vein type at the Hub Hydrothermal observed in the hydrothermal breccia. magnetic (altered to chlorite) veinlets diorite and is often porphyry brecciated Quartz, Ca Quartz + Fine-grained magnetic Straight-edged, combtooth quartz and magnelite in - - R Hub Diorite Associated with biotte - magneite atteratioCrosscstn Hub diorite Ia veins from Cannell at at., Magmatic plagioclase, centre of vein and are found 2005 magnetite truncated in clasto of the hydrothermal E breccia a Sulfide, chlorite Sulfide (chalcopyrite, pyrite, rare Thin (<5 mm), abundant, sulfides form commonly in C R C Hub Diorite Form the centre to re—opened veins? Crosscut by quartz + 2 chlorite veins Magmatic (quartz and molybdenite) centm of veiniet, often have chlorite or sericite halo Chalcopyrite, pyrite and rare molybdenite. sulphide veins sericite) (<3mm) Vein selvages absent. Molybdenite Dominantly molybdenite (a pyrite) Thin (<1mm thick), stringers of molybdenite. Fracture- - C C Hub Diortte Intense, coarse-grained sencite haloes Crosscut Hub Diorite stringers coating texture on fresh surfaces, extending up to 5 mm into host diorite. Quartz 1- Sulfide Quartz - chalcopyrite - bomite Thick (up 1040 mm) straight-edged veins. Chlorite ± C - C Hub Diorite Associated with potassic alteration. Crosscut Sulfide, 2a/2e veins from Cannell ci at., Magmatic muscovite selvages from 2 mm to 10mm into host Sulphides are chalcopyrite, pyrite, rare chlorite (quartz and 2005; B veins from Gustafson rock. bornite. sericite veins & Hunt, 1975) Quartz - white mica Quartz - muscovite, (a chalcopynte), and rare Massive-textured, interlocking quartz and muscovite - - R Hub Diurite Unknown Magmatic pyrite crystals. Gypsum - sulfide Gypsum (after anhydrite), molybdenite, chalcrThick (10-60mm), straight-edged; sulfide seam R C R Hub Diorite Phyllic haloes (sericite); suiphides are Cronscuts the Hub 3 veins (PH) stage from Hydrothermal L (molybdenite) chalcopyrite, pyrite and molybdenite and diorita Cannell et al., 2005; D-veins Main Mo-rich tend to be coarne-grained and parallel to (Gustafson & Hunt, 1975). fluid) vein walls e Carbonate Carbonate (some gangue and sulphide) Sericite and chlorite babes - up to 1 mm thick R R C Hub Diorite Phyllic babes; feldspar destructive. Crosscut all 1,2,3 4c veins veins. Mineralization Disseminated Fine-graised disseminated chalcopyrite, Bomita and guiana are rarely observed. Chalcopynte Hydrothermal Accompanied by hydrothermal biotite and Abundant Ihorughout N/A sulphides mulybdenite, bomite, pyrite and trace galena readily developed in the hydrothermal breccia. Pyrite breccia and magnetite. Pyrite is typically accompanied main diorile phase and chalcopyrite am closely associated, rarer in Hub by chlorite development and in hydrothermal diorite breccia Disseminated Coarse grained pyrite Range from 5-10 % disseminated pyrite in sericite- Hub diorile; Dominantly developed in the feldspar- Crosuculs the Hub N/A Late Magmabc pyrite altered porphyry dyke Feldspar- porphyry dyke. diorite and porphyry dyke hydrothermal breccia. Disseminated - Coarse-grained chalcopyrite, pyrite Sulphides grains occur in void spaces in breccia Hydrothermal Associated with potassic alteration, Post-intrusion and N/A Late void filling brenda hydrothermal breccia brecdiution hydrothermal sslphides A relative scale of the estimated vein abundance (VA) and Cu, Mo abundance for each vein stage: A = abundant, C = common, R = rare, - = absent ,Mássive calcite Figure 5.10: Photographs showing major vein types, alteration haloes and cross cutting relationships from the Charlie Northwest Copper areas. A) Sub-vertical, early calcite vein, crosscut by barren, dogtooth quartz vein. B) Shallowly dipping dogtooth quartz vein with pyrite. C) Epidote vein crosscut and offset by later quartz vein proximal to the Northwest Copper pluton. D) Hand sample of massive calcite vein with diffusive epidote - chlorite alteration selvage affecting the host Powell Creek Formation. E) lntergrown quartz and calcite vein from within the Tchaikazan River Formation. F) Quartz- calcite vein, massive calcite infilling quartz vein. Chlorite Th Epidte E C) It) c’.J 130 Figure 5. 11: Photoplate showing the styles of veining at the Hub porphyry system. A) Quartz vein with centre-fill of magnetite-biotite crosscutting the hydrothermal breccia. B) Cross-cutting relationship between a quartz vein and a biotite (altered to chlorite) vein. C) Planar, straight-edged quartz vein with chalcopyrite in centre-line, crosscutting the hydrothermal breccia. D) Coarse muscovite selvage to quartz vein. E) Thin section in crossed polarized light, showing a quartz vein cross-cutting a chalcopyrite-quartz stringer. 131 Figure 5.12: Photoplate illustrating the major styles of mineralization in the Hub porphyry intrusive complex: A) Quartz - chalcopyrite stringer, cross-cut by quartz-only vein. B) Drill core showing quartz - sulphide composite vein, suphides include molybdenite and pyrite. C) Stringers of chalcopyrite with intense chlorite halo and sericite-altered host rock, viewed in crossed polar. D) Same as in C but viewed in reflected light. E) Clustering of sulphides. Pyrite forming the largest sulphides, with magnetite and chalcopyrite. F) Surficial coating of molybdenite on fracture surfaces. 132 I’ GA An:.V Spui Miiq’i Del WD I I 20 pin 150kV 6.0 2612x 066 10.1 Figure 5.13: Photoplate of back-scatter SEM images from the Hub porphyry deposit: A) Chalcopyrite (1) and pyrite (2) in void space of the Hub breccia. B) Euhedral quartz crystal infihling as cemen. C) Void filling chalcopyrite(1), with inclusion of fluroapatite, and pyrite (3). D) Biotite (Bl)-magnetite (MG) altered clast. E) Galena found in the biotite-magnetite altered breccia. 133 Table 5.3 -Summary of commonly observed vein types, alteration and mineralization observed in the Charlie-Northwest Copper area. Vein Name Mineralogy Features Orientation Abundance1 Associated intrusions, alteration, sulphides andCu Mo VA rock types Quartz, chalcopyrite - pyrite - galena Native Copper + Quartz-carbonate + native disseminated copper native copper Thick (up to 4 cm), combtooth-texturect vein, with centre-fill of sulphide. Thin (<3 cm), massive, planar-sided veins, with disseminated and stringer native copper developed at vein margins, also often associated with disseminated native copper. C - C Observed dominantly Tctraikazan River Formation: volcanic fades. C - R Malachite and chyrsocolla used as vector towards these veins. Observed in the Powell Creek Formation only. Chalcocite Chalcocite + malachite, chrysocolla Thin (3- 15mm thick), often associated with quartz stringers. Secondary copper carbonate minerals. Black, metallic lustre to chalcocite C - R Preferentially developed in the resedimented facies of the Powell Creek Formation. Intense epidote alteration of plagioclase in andesite host rocks. Quartz- diaspora - tetrahedrite Quartz, diaspore, tetrahedrite Brecciated vein, with quartz, diaspora and coarse tetrahedrite (up to 5%). Tetrahedrtte is coarse grained (up to 10mm) and forms veinleta. - - R Oxidation developed on surfaces. Diaspora alteration developed around brecciated, mineralized (tetrahedrite) quartz vein. Epidote - Epidote - chalcopynte - clialcopyrite - magnetite (rare garnet) magnetite Combtooth Quartz and Calcite quartz and calcite centre Massive Calcite - only carbonate Quartz - Quartz and calcite carbonate Massive Quartz Quartz -only Combtooth Quartz (± suTpflides) Quartz Massive epidote, chalcopyrite, and magnetite, rare pyrite and garnet. Magnetite forms thin (up to 7 mm thick) stringers. Combtooth quartz with centre-fill of calcite, Shallowly dipping (25’ to EINE) Massive calcite (2-100mm) thick veins, Randomly oriented. Typically planar. Quartz crystals intergrown with fine-grained calcite. Multiple generations of quartz. Milky quartz in planar-sided veins (10-70mm thick). Combtooth quartz, growing to centre of vein. Sharp, planar margins. Suiphides (chalcopyrite. pyrite and rare galena) form in these veins. Epidote only. Veins range from (20- 100 mm thickness). Massive calcite. Veins range in thickness from mm up to 50mm. Typically planar vein margins. C - R Found in zone surrounding the Northwest Copper pluton. 10 - 50 mm thick selvages of chlorite and illite. Wallrock andesite (Powell Creek Formation) strongly magnetic. R R R Creamy, massive calcite, appears to be later infill to combtooth quartz vein. - - C Vein margins exhibit chlorite. epidote, calcite haloes up to 20 mm in host andesite R R R Chlorite haloes to veins, chlorite replacing plagioclase and homblende in andesite. - - C Devteoped in Tchaikazan River Formation and Powell Creek Formation. Epidote selvages up to 10mm in andesite host (07-170). R R R Restricted spatially; north of the Hub porphyry. Little or no alteration setvages. These veins are often crosscut by sub-vertical carbonate veins. - - C These veins are often closely associated with milky, quartz veinlets. Illite alteration haloes (up to 80 mm into host rock). - R R Chlorite, epidote, calcite alteration extending up to 20 mm into host andesite is common Conibtooth quartz - sulphide Epidote - only Massive, fine-grained epidote veins Calcite veins Massive calcite 79/135, 13/335. Shallowly (16- 38’) to NW Two dominant orientations: 226/46 and 331/81 A relative scale of the estimated vein abundance lIA) and Cu, Mo abundance for each vein stage: A = abundant, C = common, R = rare, - = absent Figure 5.14: Photoplate of the variation in vein-types, composition, alteration, and textures of veins within the Charlie-Northwest Copper areas. A) Planar quartz-epidote vein with chlorite-altered andesite host rock. B) Intense chlorite, calcite, albite, quartz alteration affecting a high-density veined area. C) Irregular, chaotically-organized carbonated veining in chlorite - altered andesite host rock. D) Epidote veining, with quartz alteration selvage, E) Intense epidote veining, with quartz selvages. F) Massive calcite, with coarse muscovite crystals. B - Hemame’ I k 135 Figure 5. 15: Photoplate showing the styles of hypogene and secondary mineralization in the Charlie- Northwest Copper area. A) Chalcopyrite in planar, quartz vein hosted by the Tchaikazan River Formation volcanic facies. B) Quartz vein from the Charlie area with chalcopyrite, pyrite and galena in reflected light, C) Stringers of native copper, malachite staining and associated quartz veinlets in volcanic rock of the Powell Creek Formation. D) Disseminated native copper in quartz vein, with intense epidote alteration in the surrounding host andesite rock. E) Native copper in reflected light from thin section, same sample as seen in C. F) Quartz-chalcocite vein in re-sedimented facies of the Powell Creek Formation. 136 AStage Vein Early Main Late Mineralogy Mineralization Mineralization Mineralization I Mag - Bio (Cl) II Qtz-Mag±Cpy —. III Qtz - Mag ± Cpy ± Py — IV Qtz ± Mo ± Cpy ±Py — — — — V Qtz-Py-Cpy VI Py±Cpy VII Anh veinlets VIII Qz±Anh+Py+Ser Vilil Qtz - sulfide poor Mag: Magnetite, Bio: Biotite, Qtz: Quartz, Cpy: Chalcopyilte, Py: Pyrite, Anh: Anhydrite, and Ser: Sericite. B Stage Vein Early Main Late Mineralogy Mineralization Mineralization Mineralization I Qz-Cpy-Py±Ga . . II Qz-±Py —— ‘ III Qtz-Dia-Tet — .‘ IV Qtz-Ca-NatCu V Qtz-Ca-Chal Qtz: Quartz, Cpy: Chalcopyrite, Py: Pyrite, Dia: Diaspore, Tet: Tetrahedrite, NatCu: Native Copper, and Chal: Chalcocite Figure 5.16: Schematic paragenetic relationship diagrams for A) the Hub porphyry deposit and B) Charlie- Northwest Copper area. 137 Figure 5.17: Photomicrographs of thick sections for fluid inclusion analysis. A) Sample O6LH-064-1, showing dogtooth quartz crystals. B) Inferred primary zoning along quartz crystal margins. C) Sample O7LH-225, showing coarsely crystalline quartz vein. D) Quartz grain with pronounced growth zone of fluid inclusions. E) Thick section of sample O7LH-040, showing composite growth of quartz veining. F) Crosscutting fluid inclusion assemblage trails, indicating several generations of hydrothermal fluid. 138 Table 5.4 Table of uncorrected Oxygen stable isotope data for silciate minerals from veins in the Tchaikazan River area iur I l8- oI .,inera. 0 100Sample no. separate Vein or rock description Wt/0H2 (VSMOW) O6LH-1 12 kaolinite Kaolinite-dickite (advanced argillic) 14.5 11.7 O6LH-058-4 quartz Massive Quartz with pyrite, cpy 13.6 11.9 O7LH-1 00-4 quartz Crustiform quartz vein from Hub w/pyrite 15.8 10.3 O7LH-230 quartz Massive Quartz vein w/ garnet and epidote 16.3 14.3 O7LH-230 magnetite Massive Quartz vein w/ garnet and epidote 9.3 3.4 O6LH-HUB-09m magnetite Massive magnetite 10.2 3.7 O7LH-HUB quartz Quartz vein with pyr, cpy and mol 16.3 9.5 O7LH-132-2 quartz Massive quartz with chalcocite 14.6 8.6 O7LH-225 quartz Quartz 14.7 8.2 O6LH-HUB-38 quartz Quartz vein + magnetite 16.3 8.7 O7LH-059-2 epidote Epidote 13.8 7.5 O6LH-082A quartz Quartz from quartz-diaspore alteration 15.3 14.5 O6LH-43A quartz Massive quartz vein with py, cpy and gal 17.2 12.2 O7LH-102 quartz Quartz vein 16.5 9.5 O7LH-019-2 quartz Quartz vein 15.2 9.2 OO7LH-CHUCK quartz Crustiform quartz vein w/ pyrite 17.2 11.9 O7LH-230E epidote Massive Quartz vein w/ garnet and epidote 13.6 7.2 O7LH-NWCublade quartz Quartz from possible bladed quartz vein 13.2 9.0 O7LH-231 quartz Quartz vein proximal to NW Cu pluton 16.7 14.8 O7LH-049-3 quartz Massive quartz with minor late calacite 15.4 15.5 O7LH-142 quartz Quartz from within quartz-carbonate vein 13.2 9.4 O7LH-228-2 quartz Quartz vein in intense epidote-andesite 14.5 9.6 O7LH-HUBm magnetite Magnetite from quartz-magnetite vein 10.6 4.7 O7LH-HUBq quartz Quartz from quartz-magnetite vein 16.0 9.2 O7LH-040 quartz Dogtooth quartz-sulfide vein 15.4 12.2 Mineral 0 3D(VSMOSample no. Host Rock WthH2O separate W) O6LH-112 Kaolinite Kaolinite-dickite (advanced argillic) 6.6 -113 139 High temperature ‘-500°C granitoid andesite meteoric water magmatic water metamorphic water Cl) 0 E U) 0 2 Legend to quartz veins Northwest Copper ___ TheHub 4567 89101112 ‘13 14 8180 (%o)VSMOW Moderate temperature —350°C granitoid andesite meteoric water magmatic water metamorphic water .. 3 Legend to quartz veins Shift in isotopic values with decreasing temperature _____ ° ______________________ Northwest 2 Copper Charlie The Hub 1234567891011121314 8180H20 (%o)VSMOW Figure 5.18: A) Oxygen isotope data from powdered quartz vein material from Hub, Charlie, and Northwest Copper. Typical oxygen values for granitoids, andesite, magmatic, meteoric and metamorphic waters are shown. ö18O fractionation corrections calculated at 500°C from Matsushima et al. (1979). B) Same dataset as in A above, but plotted using a fractionation factor supplied by Matsushima et al.,(1 979) at 350°C. Notice the significant shift decrease in ö180 values into the dominantly meteoricfield. 140 6180 (%o)VSMOW Figure 5.19: Map showing the location of vein calcite isotope samples collected for analysis using carbon and oxygen stable isotopes. B) Oxygen and carbon isotopic data for calcite veins from the study area. Fields from Rollinson (1993) and Sharp (2006) and Cretaceous seawater values from Veizer et al. (1999). 4 3 2 0 —1 0 -2 0 C.) cc -6 -7 -8 -9 -10 —11 Unaltered limestone Cretaceous seawater • • O7LH-044 Magmatic water / OiL 213 _____ Meteoric water 07LH089 • O7LH-071 • • O7U-f-O49-3 i Legend to calcite vein Charlie Northwest Copper -1 0 5 10 15 20 141 Table 5.5 - Table of uncorrected Oxygen and Carbon stable isotope data for calcite veins in the Tchaikazan River area 5mm chlorite Chlorite, minor sericite Little or none Minor chlorite Chllorite altered andesite Little or none Chlorite ± epidote hematite Pervasive chlorite ± epidote Tchaikazan River Formation Powell Creek Formation Powell Creek Formation (non-massive) Coherent andesite Coherent andesite Tchaikazan River Formation volcanic Tchaikazan River Formation Powell Creek Formation (coherent) Powell Creek Formation Powell Creek Formation? Powell Creek Formation (non-massive) -7.634 12.686 -11.931 12.487 -11.863 12.418 Standard dl3C%0 d180%0Sample no. Vein-type Vein selvage Host Rock Formation Deviation (VPDB) (VSMOW) - 0.056LHOO4-1 LH044-1 LH089 LH 142 LH142 bI LH7 I LH77 LH96-1 O7LH-21 3a Calcite Calcite Calcite Calcite Calcite Calcite Calcite Calcite Calcite -5.275 -5.301 12.004 12.074 O7LH-049-3c Calcite- quartz? O7LH-171c Calcite 0.044 0.088 0.047 0.145 0.080 0.050 0.053 0.047 0.043 0.053 Chlorite Epidote -7.873 11.932 -7.678 12.279 -7.950 16.878 -3.605 13.866 -6.865 15.704 -3.605 13.866 Quartz-magnetite mineral pair LI Figure 5.20: Quartz-magnetite mineral pair from Northwest Copper, illustrating fractionation factors and corresponding temperatures based on quartz-magnetite geothermometry. Temperatures calculated using equations from Chiba et al. (1989). -r / 490 ‘“ 500 400 300 a) ci) ‘ 200 ci) C 0 0 100 -100 -2 0 2 4 6 8 10 12 I061T(K)2 143 CHAPTER VI GENESIS AND EVOLUTION OF THE MAGMATIC - HYDROTHERMAL SYSTEM IN THE TCHAIKAZAN RIVER AREA 6.1 THE TCHAIKAZAN RIVER AREA - A LINKED MAGMATIC-HYDROTHERMAL SYSTEM (S) Field relationships, geophysical anomalies, geochronology, and stable isotope data all suggest there are three centres for magmatic-hydrothermal activity in the Tchaikazan River area. These areas are: a) The Hub; b) the Northwest Copper pluton; and c) the Ravioli Ridge area. The study area, therefore, displays evidence for multiple hydrothermal systems in similar space, and time. Two of the areas are known to be different in terms of their timing (The Hub and Northwest Copper); the timing of hydrothermal activity on the Ravioli ridge is uncertain. Geochronology (see chapter III), shows that The Hub magmatic-hydrothermal system was active from 8O Ma to 7O Ma, in contrast to the 6O Ma Northwest Copper pluton. This section will present a model for the evolution of each area, and discuss geologic, tectonic, and chemical controls related to the magmatic-hydrothermal system as a whole. Schematic diagrams for the evolution of the Hub and the Ravioli Ridge areas are presented in Figures 6.1 and 6.2 and each area is discussed in further detail below. The Hub porphyry deposit The Hub porphyry deposit displays many of the features typical of cab-alkaline porphyry copper systems (e.g., Guilbert and Lowell, 1974; Gustafson and Hunt, 1975) (Chapter II). It comprises a porphyritic diorite/granodiorite intrusion and a hydrothermal breccia, the latter hosting much of the biotite ± magnetite hydrothermal alteration, and associated suiphide mineralization. Several pulses of intrusive activity are recorded within the Hub intrusive complex: diorite; granodiorite; a quartz monzonite plug; and several feldspar-homblende dykes. Outcrops of the Hub intrusive complex correspond to a large 2 km wide magnetic high in the Tchaikazan River valley (Figure 3.15). Based upon the geological interpretation of the aeromagnetic data, the Hub area was displaced (post-mineralization) down relative to the Charlie area to the north. This downward movement to the south, means that the Hub likely intruded into rocks of the Powell Creek Formation at >5-6 km at approximately 80 Ma (Figure 6. 1B). Analysis of the aeromagnetic data suggests it is unlikely that a large intrusive body lies at depth beneath the Charlie area (Figure 3.15). Hence the Charlie dykes may be related to the same large 144 intrusive centre responsible for the Hub diorite/granodiorite or may be emplaced laterally from the Hub porphyry prior to normal movement along the inferred fault now separating the two areas. The majority of the suiphide-bearing veins in the Charlie-Northwest Copper area are flat- lying or shallowly dipping. For shallowly dipping veins to form (such as those observed in the study area) several conditions must be met: a) low differential stresses, and a3 must be oriented vertical, such as that exhibited by a compressional tectonic environment. Barren quartz veins, quartz-magnetite ± pyrite ± chalcopyrite veining, and associated silicification are inferred to have begun in the Hub diorite shortly after its intrusion at —80 Ma (Figure 6.1C). The Hub hydrothermal breccia forms at the margins of the Hub diorite (Figure 6.1 D). Barren quartz veins and quartz-magnetite ± pyrite ± chalcopyrite veins are included within diorite clasts in the Hub hydrothermal breccia. There are also fine-grained andesite clasts, which are likely of Powell Creek Formation affmity (Figure 6.1 E). The biotite ± magnetite hydrothermal alteration is confined to the Hub porphyry deposit only (see Chapter V). Temperatures of 400-600°C (Seedorf et al., 2005) are required to produce this type of hydrothermal alteration assemblage. The biotite ± magnetite alteration is interpreted here as a high-temperature expression of the core of the Hub porphyry magmatic-hydrothermal system. The abundance of biotite ± magnetite in the hydrothermal breccia indicates a relatively oxidized (JO2 —NNO to HM buffer), iron-rich environment of formation (Rowins, 2000; Arancibia et al., 1996). The lack of abundant pyrite in the Hub porphyry system suggests that the current erosion level at the Hub does not reveal the ‘pyrite shell’, which is often evident in many porphyry systems (Lowell and Guilbert, 1970). The dominance of biotite ± magnetite alteration and lack of pyrite indicate that much of the Hub porphyry deposit may have been eroded and the current level shows a position deep within the central potassic zone of the porphyry model. Clasts from all intrusive rocks exposed at the Hub porphyry deposit except the feldspar-hornblende dykes are included within the hydrothermal breccia (Figure 6.1 E). These dykes are therefore inferred to be post-brecciation and post- mineralization. The breccia is largely clast-supported, but areas are locally matrix-supported. Open space cement, accompanied by Cu sulphides, and 5-10% matrix is observed (Figure 6. iF). Moderate matrix (up to 30%) and subangular to subrounded clasts, possible clast rotation, and chaotic organization provide evidence for clast transport, abrasion, rounding, and minor matrix production. Clasts with truncated veins and clasts of quartz-sulphide vein material are minor, but significant, components that provided insight into the timing relationships between hydrothermal phases. Generally the hydrothermal breccia (both matrix and clasts) is strongly overprinted by biotite ± magnetite alteration (Figure 6. iF). The field relationships do not allow the delineation of precise geometries for the hydrothermal breccia bodies. Interpretation of outcrop and drill core 145 logging showed finger-like, dykes, and pods of the Hub hydrothermal breccia throughout the deposit (Figure 3.11). Discontinuous rinds of hydrothermal breccia are intimately associated with the margins of the Hub diorite/granodiorite (Figure 6.1 D and F). The Hub hydrothermal breccia could be interpreted as a phreatic (or hydraulic breccia). Phreatic breccias are characterized by clast transport and the focusing of fluids into the breccia facies following the onset of geothermal activity (Davies et al., 2008). Renewed magmatic input from an underlying plutonic body beneath the Hub porphyry deposit could potentially provide the necessary increased heat and fluid flow capable of initiating brecciation. This energy release from underlying hydrous magmas leads to fragmentation, which in turn leads to second boiling. It is not clear from field relationships what processes initiated brecciation at the Hub porphyry. Only once the lithostatic load is breached, by the creation of fluid channelways to the surface can processes of second boiling occur (Landtwing et al., 2002). Release of magmatic fluids during second boiling and decompression is common in porphyry systems, and produces a wide variety of breccia-types accompanying the intrusions (Sillitoe, 1985). Energy release results in mixing and milling of rock fragments in an almost fluidized, clast-rich material. The Hub hydrothermal breccia is similar to breccias observed in other porphyry deposits, such as the El Teniente porphyry deposit (Cooke et al., 2005). At El Teniente, Chile, the Braden pipe truncates the Teniente Dacite Porphyry intrusion. The Braden pipe consists of a polymict rock-flour breccia containing poorly sorted clasts of all rock-types present in the deposit. Brecciation at El Teniente is thought to occur synchronously with quartz, anhydrite, chalcopyrite, bornite, and pyrite mineralization (Klemm et al., 2007). The suiphide assemblage, polymict composition, and cross cutting relationships of the Braden Pipe are similar to those observed within the hydrothermal breccia of the Hub porphyry deposit. The quartz ± chalcopyrite-pyrite assemblage is found as a cement phase in the hydrothermal breccia, indicating that significant Cu was added at this stage (Figure 6.1 G-H). The fluid pulse that caused the biotite-magnetite hydrothermal alteration can probably be attributed to introducing significant Cu ± Mo, as well as some of the chlorite-epidote alteration. Molybdenite is locally observed in association with pyrite, with chalcopyrite absent, this in interpreted as a phase of Mo-rich fluid, which is after the event that added Cu-Mo (Figure 6.11). Quartz ± anhydrite ± pyrite-sericite veins are generally sulphide-poor and likely indicate a waning in the mineralizing system (Figure 6. 1J). Quartz-pyrite-anhydrite-molybdenite veins are relatively sparse and most analogous to the D veins from Cannel et al. (2005). Quartz veining is an essential part of this high-temperature alteration and the development of intricate networks of stockwork veining is observed within the Hub porphyry 146 deposit. Such veins are also documented in other porphyry deposits worldwide; e.g., El Salvador, Bajo de la Alumbrera, and El Teniente (Gustafson and Hunt, 1975: Cooke et al., 2005). Typically quartz veins in porphyry copper deposits are inferred to form in an environment dominated by magmatic fluids, exsolved from a crystallizing plutonic body (Gustafson and Hunt, 1975; Sillitoe, 1995; Ullrich and Heinrich, 2001; Proffett 2003). Chalcopyrite-molybdenite ± bomite mineralization is associated with the Hub diorite and probably represents the main metal- introducing stage in the deposit. Barren quartz stringers are the earliest veins to occur within the Hub porphyry deposit, they are observed within magnetite-biotite-altered clasts of the hydrothermal breccias and Hub diorite. They are generally sub-vertical in outcrop and range in thickness from a few mm up to 50 mm. No alteration selvages are developed on these early barren vein sets. Quartz-plagioclase magnetite veins appear to be early in the paragenetic history of the Hub porphyry deposit. They are common throughout the Hub diorite and truncated at clast margins within the hydrothermal breccias, indicating that they formed prior to the brecciation event. Additional vein-types which are most likely associated, or synchronous, with the high temperature biotite-magnetite alteration and Cu mineralization are the chalcopyrite-chiorite-, molybdenite stringers, quartz-pyrite-, quartz- white mica (Table 6.1). Quartz-chalcopyrite veins cut earlier magnetite (altering to chlorite) stringers. Paragenetically, the veins become increasingly magnetite-poor and pyrite-rich (Chapter V) as temperatures of the magmatic-hydrothermal systems decrease, and fluids evolve to lower pH (Barnes and Czamanske, 1967) and higherjS2(Meyer and Hemley, 1967). Stable isotope 6180 data (Chapter V) for formation temperature of 350°C for quartz magnetite ± chalcopyrite veins with sericite haloes indicate that the Hub veins represent fluid compositions transitional between meteoric and magmatic values. At higher values reaching up to 500°C, which may also be possible given the spatial association of these veins to biotite magnetite alteration, the veins plot within the magmatic fluid field (Section 5.7). The Hub veins are inferred to have formed at temperatures greater than 350°C; therefore it is likely that overall the source was a magmatic fluid (Section 5.7). All intrusive rocks of the Hub intrusive complex are altered to propylitic assemblages dominated by chlorite-epidote ± albite. In the Hub diorite, chlorite-epidote alteration overprints earlier biotite ± magnetite alteration, with shreddy chlorite after shreddy biotite. Propylitic alteration at the Hub porphyry deposit was probably contemporaneous with biotite ± magnetite alteration but continued after intrusion of the unmineralized feldspar porphyry dykes (Figure 6.1K). 147 Feldspar-destructive (sericite ± clay minerals) alteration overprinted earlier alteration types at the Hub. Its intensity is variable, from minor sericite replacement along fractures in plagioclase phenocrysts of the Hub diorite, and partial replacement of plagioclase phenocrysts, to complete texturally destructive sericite alteration in the unmineralized feldspar-hornblende porphyry dykes. Intense feldspar-destructive sericite alteration is also observed as vein selvages to gypsum-suiphide, carbonate, epidote-magnetite-chalcopyrite, and epidote veins. Other vein-types lack clear cross-cutting relationships and their relative timing cannot be fully constrained. Gypsum veins are a common occurrence in drill core but were not observed at surface. They always occur within the Hub diorite and commonly contain molybdenite and pyrite seams close to the vein margins. Gypsum and anhydrite veins are common to porphyry deposits, e.g., Bajo de la Alumbrera, El Teniente, and El Salvador (Ulrich and Heinrich, 2001; Gustafson & Hunt, 1975). Gypsum can form in two ways in the porphyry environment, either replacing earlier deposited anhydrite veins through hydration, or from surface weathering (Ulrich & Heinrich, 2001). Weathering of gypsum veins was observed in the top of drill core, where a rubbly texture dominated the drill core. In contrast to the Gustafson & Hunt study (1975) of the El Salvador deposit, where anhydrite deposition occurred throughout the period of primary mineralization, the lack of Cu sulphides in the anhydrite veins observed in the Hub porphyry are more similar to that described by Ulirich & Heinrich (2001) from the Bajo de Ia Alumbrera deposit, Argentina. At the Hub porphyry deposit, the timing relationship of the anhydrite veins is ambiguous, but the occurrence in Hub diorite indicates they are related to a later fluid pulse, lacking in Cu-bearing sulphides, yet rich in molybdenite and pyrite (Figure 6.11 and J). From cross-cutting relationships it is inferred that these molybdenite—rich veins formed from a slightly later pulse of Mo-rich fluid subsequent to a Cu-rich mineralizing event. This is similar to the inferred paragenesis described by Ulrich & Heinrich (2001) for mineralization at the Bajo de la Alumbrera deposit. Ravioli Ridge The second area/centre of magmatic-hydrothermal alteration is located on Ravioli Ridge, central to the Northwest Copper area (Figure 5.1). The area comprises locally developed kaolinite-dickite, quartz-diaspore, and widespread propylitic and sericite alteration. Figure 6.2 illustrates a schematic representation for the genesis of the observed hydrothermal patterns. The area of kaolinite-dickite alteration comprises a locally developed patch of cream coloured, fine-grained rock on the western side of Ravioli Ridge. A large (4 km2) magnetic anomaly covers much of Ravioli Ridge and is coincident with the kaolinite-dickite alteration 148 (Figure 3.15). Ravioli Ridge comprises Powell Creek Formation volcaniclastic sediments to the south, grading into more massive, coherent andesite of the Powell Creek Formation to the north. A small area of diorite, and associated syenite dykes, crops out on the northwest flank of the ridge. The magnetic anomaly there is thought to correspond to an intrusive body beneath Ravioli Ridge. Kaolinite-dickite-halloysite ± montmorillonite and quartz-diaspore alteration crop out on Ravioli Ridge. The timing of this kaolinite-dominated alteration mineral assemblage is ambiguous, but it is inferred to cross-cut and post-date areas of propylitic and sericite alteration. The limited distribution of the advanced argillic, kaolinite-dominated hydrothermal alteration suggests that it may have existed above a shallow pluton (revealed from magnetic anomaly map — Figure 3.15) or it may form in a structurally controlled zone, from the focusing of acidic fluids (Shinohara and Hedenquist, 1997; Ulrich and Heinrich, 2002). The release of low-density, HC1- SO2 ± HS-rich vapor from the underlying pluton and the disproportiontion ofH2S can cause such advanced argillic alteration (Figure 2.6A). This alteration may therefore be controlled locally by faulting, creating increased permeability for fluid flow from an underlying plutonic body. Ullrich and Heinrich (2001) describe feldspar destructive alteration controlled by structures, which is most widely developed near the top of the Bajo de la Alumbrera porphyry system. It could be locally controlled by faulting and linked to increased fluid flow and rock/fluid interaction or could be linked to a pluton at depth. Heinrich et al. (2004) state that a structurally focused fluid may become increasingly acidic as the system cools to temperatures below 400°C. Dickite forms at slightly higher temperatures (-200-250°C) than kaolinite (150-200°C). Halloysite is known to occur widely in magmatic hydrothermal systems involving hydrothermally altered igneous rocks. It forms from the weathering of feldspars at even lower temperatures (60-75°C) (Hedenquist and White, 2005; Joussein, et al., 2005). The disproportionation of acid of the host-rock produces H. The result is a very acidic fluid (4 > pH > 1) capable of producing such advanced argillic alteration as observed at Northwest Copper. The Raviloli ridge area is thought to have been approximately 3-5 km deeper than the present level of exposure at 80 Ma. It is inferred that advanced argillic alteration formed from an acidic fluid. Diaspore, kaolinite, and dickite alteration are spatially related to Ravioli Ridge and known to occur at temperatures of greater than 150°C; hence the alteration observed on Ravioli Ridge may represent the effect of a hot, ascending magmatic vapor (Figure 2.6B) causing acid leaching and advanced argillic alteration. Fluid-rock interaction and fluid mixing cools the fluid and decreases the acidity. Alternatively, faulting could create corridors for the downwelling of 149 acidic fluids sourced from other vapors making the groundwater acidic. The mixing of the rock with structurally controlled acidic fluids could create such an advanced argillic alteration. The occurrence of vein-hosted native Cu and chalcocite mineralization in the Ravioli Ridge area are likely products of near-surface weathering processes, in which ground-water transports metals from a source region or leached zone to a locus of enrichment where these ions are reprecipitated as secondary ore compounds (Ague et al., 1989). Above the water table the stability fields of secondary Cu minerals are controlled essentially by pH which controls the solubilities of complexing ligands (i.e., CO2, OW, SO etc.) and determines which of the relevant Cu complexes are likely to be saturated in any given environment (Figure 6.3). Chalcopyrite may be dissolved in the leached zone of porphyry copper deposits and subsequently reprecipitated as supergene chalcocite (Figure 6.3). Locally developed malachite and chrysocolla are inferred to be related to the precipitation of these oxidized minerals from groundwaters that are saturated with respect to one or more of the various components that make up the minerals. Many of the large Chilean porphyry copper deposits exhibit developed supergene copper and oxide zones (e.g., the Chuquicamata, El Salvador, and El Abra porphyry deposits) (Robb, 2005). Northwest Copper pluton The third area or magmatic-hydrothermal centre is located around the Northwest Copper pluton. Outcrops of Northwest Copper pluton again correspond to a 2 km irregular shaped magnetic high, located in the southwest corner of the study area. Northwest Copper is spatially associated with the Hub deposit, which occurs 4 km to the northwest. The Hub porphyry deposit is also inferred to sit within the same package of Powell Creek Formation as the Northwest Copper pluton. Porphyry-style quartz-magnetite and epidote veining, rare garnet, and associated sulphide mineralization are locally developed in the andesite rock proximal to the Northwest Copper pluton. Stable isotope geothermometry indicates that the quartz-magnetite veins formed at a temperature of —500°C. This temperature is reasonable for porphyry-style main-stage mineralization as a result of fluids exsolved from an underlying pluton (Roedder, 1971; Dilles et al., 1992; Rusk and Reed, 2008). Stable isotopeö18OH2o values from quartz veins proximal to the pluton indicate a magmatic source for vein-forming fluids, likely exsolved from the Northwest Copper pluton. Stable isotope ‘8OH2o values indicate quartz veins with chlorite alteration selvages formed from a mix of meteoric and magmatic fluids (Section 5.7). Stable isotope &8OH20 and613CH20 data indicate precipitation from magmatic fluids, which is in agreement with the suggested ambient temperature of >200°C, and abundant sericite-chlorite alteration associated with many of the veins. 150 Distal hydrothermal alteration Large expanses of propylitic hydrothermal alteration, similar to those mineral assemblages observed within the Charlie-Northwest Copper area are recognized to form as part of distal alteration assemblages in porphyry Cu systems worldwide (Lowell & Guilbert, 1970; Gustafson & Hunt, 1975; Proffett, 2003; Seedorf et at, 2005). Therefore, in the simplest terms, the chlorite-epidote-albite ± calcite alteration observed in the volcanic sequences several kilometers from the Hub porphyry deposit (the hypothesized centre of the porphyry system) equates to distal hydrothermal alteration. However, as discussed in Chapter III, difficulty arises in trying to distinguish propylitic alteration from regional ‘background’ alteration, which can also consist of a mineral assemblage of chlorite-epidote-calcite. From porphyry literature, the outer limits of propylitic mineral assemblages in some cases are poorly defined, mineralogically and texturally, leaving an assemblage that is difficult to reconcile with regional metamorphic processes (Lowell & Guilbert, 1970; Wilson et al., 2003). Intense epidote alteration and veining, locally accompanied by elevated Cu content (chalcopyrite) in and around the Northwest Copper pluton provides evidence for the juxtaposition of several magmatic-hydrothermal centres. An increased density of veining (epidote, quartz-epidote, quartz-calcite) commonly accompanies the distribution of strong epidote alteration. This spatial distribution can be broadly tied to the Northwest Copper thrust fault system and locally to the Northwest Copper pluton. Mineralization and alteration is inferred to post-date movement of the thrust faults, which are inferred to have been active from 87-84 Ma (Rusmore and Journeay, 1991). Timing of mineralization in the Northwest Copper area is unknown; more data is needed to precisely date the hydrothermal system and sulphide minerals. The timing of mineralization at the Hub porphyry deposit is inferred to have occurred between -80 and 69 Ma, from U-Pb age of the Hub diorite and an Ar-Ar age from a cross-cutting post-mineralization feldspar-hornblende dyke. Interpretation of hydrothermal systems within a porphyry-epithermal continuum Spatial and temporal links exist between the magmatic-hydrothermal systems outlined above. Temporal links exist between the intrusive rocks of the Hub porphyry and porphyry dykes from the Charlie area. The kaolinite-dickite-halloysite alteration at Northwest Copper is unlikely to have been sourced from a causative intrusion form the Hub porphyry system. The Hub system is inferred to have formed at a depth of >5 km, whereas the inferred vertical position of the clay dominated alteration is likely only several hundred metres above the Hub system, assuming undisturbed stratigraphy. The clay-dominated alteration likely formed at temperatures between 151 125°C (dickite) and 200-300°C (kaolinite) (Keller, 1978). The advanced argillic alteration (quartz-diaspore) atop Ravioli Ridge is typical of high-suiphidation epithermal environment (Muntean and Einaudi, 2001). This alteration assemblage is similarly unlikely to have a genetic link to the porphyry-style mineralization observed at Hub, given the limited vertical exposure above the Hub. However, the large magnetic anomaly beneath Ravioli Ridge could represent evidence of a shallow pluton capable of producing such acidic alteration. Synchronous production of high-temperature biotite ± magnetite alteration at Hub and high-suiphidation epithermal-style alteration at Northwest Copper is therefore unlikely owing to inferred vertical distance between the two areas. Contrasting Ar-Ar and U-Pb ages for the magmatic centres in the study area suggest hydrothermal alteration is related to several temporally-distinct magmatic hydrothermal systems and at present there is not enough data to definitively suggest which hydrothermal alteration assemblages are attributed to which magmatic centre. 152 Figure 6.1 - Schematic diagram for the evolution of the Hub porphyry deposit. See chapter VI for detailed description of diagram. Intrusion of Hub diorite —80 Ma >3km + +! + +\ + + Andesite - probably Powell Creek Hub diorite/granodiorite Hub hydrothermal breccia Feldspar-hornblende dyke Quartz vein with Cu sulphide Quartz vein with biotite-magnetite E] Quartz - white mica vein — Sulphide stringer + chlorite + quartz — Molybdenite stringer — Anhydrite veins — Carbonate veins • Disseminated chalcopynte, bomite O Disseminated Fe sulfide - Pyrite Fluid flow path 153 Figure 6.2 - Schematic model for the establishment of a magmatic-hydrothermal system beneath Ravioli ridge in the Northwest Copper area: Key features include the Advanced argillic and kaolinte-dickite alteration, a shallow diorite pluton, syenite dykes and vapor alteration 154 Figure 6.3 - Eh-pH diagram showing the stability fields of selected copper minerals at 25°C and I atmosphere (From Robb, 2005). 1.0 0.5 0 0 -0.5 -1.0 1 01 a, Q. U, 0 E a 0. I v.40 1 I 0.83 0 2 4 6 8 10 12 14 pH 155 CHAPTER VII INTEGRATED GEOLOGICAL EVOLUTION OF THE STUDY AREA Conclusions and Implications Cretaceous igneous rocks in the study area (or in the Southeast Coast Belt), and by implication the economic deposits which they give rise to, were generated by processes associated with subduction of oceanic lithosphere beneath the ancestral North American continental margin (Sillitoe, 1980). Kinematic analysis of the surrounding area indicates an active period of crustal shortening from the mid-Cretaceous to the Tertiary. Within the study area, structures mapped at Northwest Copper perhaps best illustrate these older over younger structural relationships, where the older Tchaikazan River Formation overlies the Powell Creek Formation. The relationship between faulting and mineralization is still not well constrained, but most evidence supports faulting prior to, or at the waning of, the main mineralizing event. A magmatic-hydrothermal system or systems are inferred to be centered on calc-alkaline intrusions in the Hub and Charlie-Northwest Copper areas. Magmatism in the Tchaikazan River area took place in an island arc setting. Porphyry copper mineralization in the area formed in two distinct stages, the first during arc evolution, at 80 Ma, and the second, at approximately 60 Ma, resulting from periodic during the Eocene. The intrusion of numerous caic-alkaline plutons and stocks, and dykes of feldspar-porphyry and andesite to, basaltic composition is envisaged for the Tchaikazan River area during the Cretaceous. The Tchaikazan River area therefore represents a transitional depositional environment between the Gambier arc to the west and marginal basins of the Methow-Tyaughton terranes to the east. Figure 7.1 provides a schematic temporal diagram of the major tectonic, intrusive, magmatic-hydrothermal, and exhumation events recorded in the rocks now observed in the Tchaikazan River area. The tectonic framework for the development of magmatic-hydrothermal systems in the Tchaikazan River area portrays regional movement prior to the development of porphyry-style mineralization (at least at the Hub area) (Figure 7.1). Contractional deformation is known to have occurred in the area from -87-84 Ma. This deformation led to the thickening of the stratigraphic sequence, with the Tchaikazan River Formation thrust upon the younger Powell Creek Formation. A major normal fault is inferred to exist between the present location of the Hub porphyry deposit and the Charlie area; this fault was not observed during geological mapping, but its interpretation was aided by aeromagnetic data. The inferred displacement of this normal fault is down to the south. This relative movement of units places the Hub porphyry 156 deposit in rocks that are inferred to belong to the Powell Creek Formation. The Powell Creek Formation is the youngest stratigraphic unit observed in the study area, and the intrusion of the Hub porphyry into it can be explained by creating a compressive tectonic regime, whereby regional thrusting occurs prior to intrusion of the Hub diorite/granodiorite. This deformation creates a thickened stratigraphic package comprising mainly Cretaceous age rocks into which the Hub intrusive complex was intruded, at a depth more akin to the generally accepted depth of porphyry systems (e.g., 2-6 km). Physical expressions of a large-scale magmatic-hydrothermal system are evident throughout the Tchaikazan River area, and include veining, sulphide mineralization, and zones of hydrothermal mineral assemblages. The first pulse of magmatic-hydrothermal activity occurred at 80-70 Ma, and is centered on the Hub porphyry deposit (Figure 7.1). High-temperature biotite ± magnetite, hydrothermal brecciation, silicification, and quartz-sulphide mineralization was likely coeval with chiorite-epidote and sericite alteration of the Hub diorite/granodiorite intrusion. Late-stage feldspar-hornblende porphyry dykes cross-cut all other lithologies and record the fmal pulse of magmatic activity in the deposit. The similar ages and geological composition of the intrusive rocks of the Hub porphyry to the dykes observed in the Charlie area suggest that mineralization at both localities are likely products of magmatism from the same large calc-alkaline intrusive body. The magnetic anomaly supports the theory of a large intrusive body at depth to the west-southwest of the Hub porphyry deposit, which could easily provide a magmatic source for the intrusive rocks located in the Charlie area (Figure 7.1). The Northwest Copper area contrasts with the Hub intrusive complex, in terms of mineralogy, alteration, and age. The widespread propylitic alteration present in much of the Northwest Copper area cannot be easily linked to either the 80 Ma or 60 Ma magmatic hydrothermal events. Geochronology confirms that 80 and 60 Ma intrusive rocks crop out in the Tchaikazan River area. Copper mineralization and hydrothermal alteration is spatially related to the Northwest Copper pluton and possibly an intrusive body beneath Ravioli Ridge. The localized kaolinite-dickite and advanced argillic (quartz-diaspore) mineral assemblages may be the result of an acidic condensate from an underlying plutonic body (Figure 7.1). In conclusion, the Hub porphyry deposit is of similar age to other magmatic hydrothermal deposits in the Taseko Lakes region, in particular the 80 Ma Prosperity porphyry deposit. The similar age and hypothesized depth of the Hub porphyry and Prosperity deposits likely correspond to an 80 Ma suite of magmatic-hydrothermal systems in the Taseko Lakes region which formed in response to crustal-scale subduction-related magmatism. The recognition 157 of similar rock types, hydrothermal alteration styles, and mineralization offer evidence that the mineral showings located in the Tchaikazan River area are related to the same suite of porphyry producing cale-alkaline magmatism observed in the wider Taseko Lakes region. 158 1 km 2 km 3 km 4 km 5 km 6 km Normal faulting ‘ Northwest Copper pluton Present erosion level Advanced argillic alteration “-‘ — Sulfide minerlizationCj Hub diorite intrusion Depth of closure temperature Fluid flow path Figure 7.1- Schematic integrated geological evolution oftheTchaikazan River area, illustrating emplacement of plutons, exhumation, tectonic history and magmatic-hydrothermal systems (Not to scale). 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(1991): Calculation of oxygen isotope fractionation in metal oxides. Geochim Cosmochim Acta, 55. pp. 2299-2307. 168 APPENDIX I DRILL LOGS (2008 FIELD SEASON) 169 EQUITY EXPLORATION DRILL LOGCONSULTANTS LTD. Project: Taseko Collar elevation: 1594.0 m Hole: 08TsK-01 Azimuth: 320.0’ Proposed: O8TSK-A Dip: 6500 Location: 453207 m East 5668942 m North Length: 25.00 m Prospect: Hub Date started: Date completed: 2008/07/18 2008/07/19 Claim: 354057 Objective: Logged by: L.Hollis To follow-up on prospective geochemical surveys and to try and intersect the northern margin of identified Drilled by: No Limit magnetic high. Assayed by: ALS Chemex Core size: HQ Dip tests by: ReflexSS SUMMARY LOG: 0.0 -4.6 m: CASING 4.6 -25.0 m: DIORITE: CL- & MS-altered; QZ veining; 0.5% CP, tr. BO, tr. MO, 0.5% PY 25.0 m: EOH 170 I,—7% /7 \,9 I—//% // ..:t// /7— I,— /7—/7% // ‘// 7/ \// 7/— ,, /7% /7— , // ‘I /7—/7% /7 // // \\// // 15.90 18.80_Diorite__________________________________ Medium-grained diorite. Moderate core competency. CL- altered matrix and mafic phenocrysts. Large PF phenocrysts. Moderately dense QZ+I-PY+I-CP veining. PY /7 stringers with mm-scale MS selvages. Small faults (less than 10 cm) lined with CYorMU. 0.00 4.60_Casing I o._ 4o qg flinritA Project: Taseko Hole Number: O8TSK-01 From To Rock-type & Description From To Width Sample CU Mo Au 0 5 5 4 43 4° Grey-green, medium- to coarse-grained diorite. Core is moderately competent5 CL and MS-altered. QZ veining throughout, most are up to 2 cm wide. <c 5.11 Fault 25.00°> <@ 6.60 QZ Vein 10.00°> <1 6.90 CY Fault Gouge 80.00°> ss In QZ veins Pyrite 0.50%su In QZ veins Chalcopyrite 0.50%sa In QZ veinslon fractures Bomite 0.10%sa Of BI & HB Chlorite 3.00°ae Alteration of PF Sericite 2.00°c 4.StL_ L5Q_ 9,SQ_ G0800501 1185_ 46___ Q.Q0f .SL. 7.0L. 1.50._ G0800502 1150_ 45___ 0005 L00_ 8.SQ_ LSL. G0800503 SZS_ 2S.__ <Q.005 \r 9.90 15.90_Diorite I Greyish-green, moderately competent diorite. Contains large, oscillatory.zoned PF phenocrysts. Mafic minerals are weakly altered to CL QZ veining with MS selvages (Ito 20 mm In width). @ 9.90 QZ-PY Vein 30.00°> < 10.14 CY Fault Gouge 20.00°> <@ 10.40 QZ-PY Vein 40.00°> <t 12.60 QZ.PY Vein 40.00°> e Alteration of BI phenocrysts Chlorite 3.00°ce Alteration of large PF phenocrysts Sericite 200°csc In QZ veins Pyrite 1.00%c e In QZ veins Chalcopyrite 0.50%ce On fractures within QZ veins Molybdenite 0.10%sos On fractures with CP & PY Bornite 0.10%c 15 850 1ono i.sn ° 4 8.50 10.00 I50’”°°’°” 415 115 <0.005 IflflA 11 50 1 50 11.50 12.50 Inn 42.500 i45fl Inn nnannsn7 10.501 .4ARn un 252 in ennnc i.5ueuuouo .5AA AA enflnc IAcfl ICUn Inn ,uc .5 ,05 2 en anc - en nnc —1 <@ 16.40 QZ-PY-CP-MO Vein 60.00° 10.00mm> 16.60 17.60 16.60 16.60 1.00 G0800511 612 18 <0005 17.60 18.60 1.00 1_oo,,’°°,,S°.-° 321 17 <0005 192 2 <0.005 2008111103 Equity Exploration Consultants Ltd. *graphic log notto scale Page 1 of 2 <@18.40 QZ-CP-PY Vein 60.000 10.00m> Pervasive green tinge to rock Chlorite 3.00°c a Sencite alteration along veins margins and alteration of plagloclase phenocrysts Sericite 2.00°w< In OZ veins, typically along vein margins Pyrite 0.10%>> a In QZ veinslon fractures Chalcopynte 0.10*>> <<In —10 mm wide QZ veins Molybdenite 0.10%>> 18.80 21.00_Diorite I Green-grey, medium.grained diorite. Core competency is good. CL is the main alteration mineral, altering mafic phenocrysts and matrix material. Large P1° phenocrysts are dominant. Minor quartz veining, most containing sulphides (PY, CP, and trace BO) with MS selvages. <@ 18.90 QZ-PY-CP Vein 60.00° 8.00mm> 20 - <@ 19.30 QZ-PY-CP-BO Vein 26.00° 6.00mm> a Alteration of matrix Chlorite 2.00°c a P1° phenos Sericite 2.00°ca In QZ veins Pyrlte 0.50%s a In QZ veins Chalcopynte 050°s a On fractures in QZ veins Bornite 0.10%a a In mm-size QZ veins Magnetite 0.10<A>m 21.00 25.00_Diorite I Greylsh.green, medium-grained diorite with P1° and HB phenocrysts. 02 veins wit strong MS selvages increase in width and MO content <@ 21.40 QZ-PY Vein 30.00° 10.00mm> <@21.70 QZ-MO Vein 70.00° 30.00mm> <<Pervasive Chlorite 2.00°s a Selvages to 02 veins Sericite 2.00°c <<In 02 veins & trace disseminated Pyrite 0.50%s a In some 02 veins Chalcopyrtte 0.10°c ° Along margins of 02 veins Molybdenite 0.50%s 9cnn 2 fin FAIl I Project: Taseko Hole Number: O8TSK-O1 From To Rock-type & Description I From To Width Sample <<pm ‘p°m pi a Sc 0 3 0 0. 0 41 40 5 0 4 , // of /“!‘ I— I, I— 0 4’ii // i // i/; /1 I,—//% II II ‘0, if’ ii f, ii— 0 lit? 1I0_ ILSL tQQ_ 130800514 <tSI_ 8__ -0.0D6 19.5Q 2A.7Q IJL. G0800515 ‘114_ 2L_ c0.0ll6 20.Z0 ‘.t8Q_ tIQ_ G0800516 ‘.86 4__ <tOOL )I <<fl ,, on i in A5AAc17 7A 2 <A AAS 9QA 9A9fl lSA tAkAfl51R <11 5 A Af)5 2008111103 Equity Exploration Consultants Ltd. °graphiclognottoscale Page A EQUITY I CONSULTANTS LTD. DRILL LOG v4 Project: Taseko Collar elevation: 1594.0 m Hole: O8TSK-02 Azimuth: 320.0° Proposed: O8TSK-A Dip: -60.0° Location: 453207 m East 5668942 m North Length: 304.20 m Prospect: Hub Date started: Date completed: 2008/07/19 2008/07/27 Claim: 354057 Objective: Logged by: L.Hollis To follow-up on prospective geochemical surveys and to try and intersect the northern margin of the Drilled by: No Limit identified magnetic high; drilling at same location as drill hole O8TSK-01, but at a shallower dip. Assayed by: ALS Chemex Core size: HQ/NQ Dip tests by: Reflex MS SUMMARY LOG: 0.0 - 4.6 m: CASING 4.6 - 57.7 m: DIORITE: MS-altered; QZ veining; 0.5% CP, PY, tr. MO 57.7- 60.4 m: BRECCIA: MG-Bl-CL-altered; QZ veining; 2% PY, 1% CP 60.4- 65.8 m: ANDESITE: MG-Bl-altered; 2% PY, 1% CP 65.8- 86.70m: DIORITE: MS-altered; QZ veining; 2% PY, 1% CP 86.7- 101.Om: ANDESITE: MG-Bl-altered; QZ veining; 0.1% PY, 0.5% CP 101.0- 224.Om: DIORITE: MG-SI-altered; QZ veining; 0.3% PY, 0.3% CP, 0.01% MO 224.0- 245.Om: BRECCIA: MG-Bl-altered; QZ veining; 0.5% CP, 1.5% PY, 0.05% MO 245.0- 304.2m: ANDSITE: MG-Bl-altered, MS on fractures; QZ veining; 0.5% CP, 1.5% PY, 0.1%MO 304.2m: EOH 173 a b () F’ ) F’ .) F’ ) F’ ) F’ ) 0 0) 01 . F’ ) 0 CD - 0 ) . C ) - m CD 0 0 0 0 0 0 0 0 0 0 0 0 0 0 - < 01 01 01 01 0 1 0 1 (3 1 (3 1 0 1 01 01 01 01 0 ) c D c D ( D ( 0 ( o ( o ( o c C o D c D ( D p - . F’ ) CD - F’ 0 ) . . C, ) F’ ) 01 CD 0 ) . F’ . 0 n m 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o x C. ) C. ) C. ) C. ) C. ) C, ) C, ) C, ) C. ) C. ) C, ) C.’ ) C. ) C. ) > F’ ) F’ ) F’ ) F’ ) F’ .) - ‘ . F’ ) F’ ) F’ ) F’ ) F’ ) F’ ) F’ ) F’ ) N P F ’ ) C C .) F’ ) p p 0) CD . CD CO . - J 01 01 F’ ) - 01 (3 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 — I I I 0 C) 0 (11 — 0 ’ p - CD o — C, 01 — 4 (I) 0 - I CD g 2 - ‘ Ø C D 0 00800519 843 ______ 00800520 393 00800521 487 00800522 427 G0800523 377 __ __ 00800524 566 00800525 00800526 325 00800627 259 00800528 457 00800529 427 00800530 443 G0800631 326 G0800532 440 G0800533 372 00800534 268 00800535 245 00800536 294 Project: Taseko Hole Number: O8TSK-02 I From To Rock-type & Description / _________ ______ ppm 0.00 6.00_Casing I 4.60 23.80_Diorite I To Sample ‘ II I,— 10 9— // \// /1 ‘// 9— K” 11 9 I, 4,, 1/ 20 //°t9 /7°..”,, 9f I 23.80 39.00_Diorite I /4”I Green, fine- to medium.gralned diorite. Core competency is moderate. QZ vein width varies from stringers to 50 mm. Dominant vein orientation is —90 to con25 Fine-grained, porphynitic diorite. The fine-gralned nature of the core is assumed to be an alteration effect. Core competency is poor. Weathered material at the top of the hole. Strong MS alteration of fracture planes. 2 cm wide brecciated zone at top of hole which truncates QZ veins - QZ-MG-PY infills voids. Pervasive (matrix & phenos) Chlorite 3.00°sss On fractures Sericite 3.00°c a Pyrite 0.50%a o Chalcopyrite 0.30%c , Molybdenite 0.10%s <@ 5.00 CY-nch Fault Gouge 35.00°> <@ 6.30 QZ Vein 70.00° 10.00mm> <@ 6.60 QZ Vein 25.00° 8.00mm> <@ 7.75 QZ-PY.MO Vein 65.00° 15.00mm> <t 11.70 QZ-PY-CP Vein 35.00° 10.00mm> <@ 13.10 QZVein 70.00° 20.00mm> <@ 13.20 QZ Vein 20.00°> <@ 14.70 CY Fault 80.00°> <@ 16.50 02 -PY-MO Vein 70.00° 20.00mm> <@ 17.00 02 .PY.CP+metallic dark grey mineral Vein 60.00°. 10.00mm> < 17.15 green CY Fault 40.00° 50.00mm> <c 17.60 green CY Fault 25.00°> <@ 18.00 green CY- MS? Fault 40.00° <@ 19.00 QZ-PY Vein 6.00° 3.00mm> <@19.80 QZ.PY.M0 Vein 30.00° 8.00mm> <@21.40 QZ-MO Vein 70.00° 25.00mm> <@22.30 QZ-GY-PY Vein 60.00° 40.00mm> <@ 22.50 CY.MS Fault Gouge 40.00° 15.00mm > <@ 23.60 QZ.PY-MG Vein 70.00° 3.00mm> Cu I ppm 9 010 0 \ \100° I 4° ‘1 Au ppm <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 0.007 <0.005 <0.005 <0.005 0.005 <0.006 <0.005 <0.005 0.008 <0.005 <0.005 0 0 0 5 0 ‘, at From -- -- -- — 40 40 40 0 4 H H .jj JL 050 5 5L H 25.50 00 0 50 0 9 3 5 5 6.50 Width 5 00 0 0 1.00 2008/11103 Equity Exploration Consultants Ltd. *graphic log notto scale Page I of 11 00800537 00800538 IG0800539 j29o lii 1<0005 116 1<0.005 [<o.005 Project: Taseko Hole Number: O8TSK-02 Cu Mo AuFrom To Rock-type & Description I From To Width Sample 400 0.50 4050 40 0 0 4 1.00 G0800541 307 27 <0.005 I am 27.89_ 29.89_ I.09_ G0800542 475_ 4L_ <0.095 28.50_ 29.5L 1.99_ G0800543 491._ 7L_ 0.905 29.5.9.. tOQ_ G0a00544 5I2 24__ Q.9QL 2 tOL 954 39.89. Th5L. 1.OL G0800546 ZIL_ 1L._ 9.995 3i89_ 12.5L. t0L G0800547 414_ IL._ <Q.995 32.59_ Th5L tOO G0800648 42L 14 9.00L 33.59 4.50_ 1.P0_ G0800549 212_ Zt_ 9.9Q 45 tSL 241 23 <000C 39 39.59 L 34 <95 39.59_ ILSL. tOO_ G0800552 473_ it_. <J.095 37.5Q_ 38.S0. LQL_ G0800553 374_ 42_ <0&Q5 Q0 Q89Q55L 434 83 <95 axis, with another prominent set at 35-45 to core axis. Fracture-coating PY-MO. Trace-minor CP in QZ veining as blebs. Areas of intense MS alteration between cross.cutting veins. Strong CL alteration of diorite. a 36.10. 37.20 Alteration of PF & HB Sericite 4.00*5 Cross.cutting, MS selvages Quartz Veining 3.00°io*o 30.74- 31.20 clay Fault Zone a a Chlorite 2.00 a 23.80- 27.50 Chalcopyrlte 0.1%a a 36.10- 39.00 Chalcopyrite 0.1%a so 23.80- 27.50 Molybdenlte 0.02%s e 36.10- 37.20 Molybdenite 1.00%a a Pyrite 0.30%a a Chalcopyrlte 0.30% 30 — <@ 23.85 QZ.PY Vein 30.00° 8.00mm> <t 24.40 QZ-PY Vein 50.00° 7.00mm> <i 26.10 QZ Vein 60.00° 10.00mm> <i 23.80 QZ Vein 30.00° 15.00mm> <@ 27.30 (1) QZ-CP Vein 45.00°-35.OOmm> <o 27.45 (2) QZ-CL (previously BI?) Vein 70.00° 8.00mm> <@ 28.50 QZ-FP (CL selvage) Vein 89.00° 25.00mm> < 29.40 Planar margins, lilite? Fault Gouge 90.00° 40.00mm> 33 — <c 29.55 QZ-MO.PY Vein 85.00° 55.00mm> <t 29.94 QZ-PY Vein 40.00° 15.00mm> <@ 31.00 QZ-PY-CP Vein 30.00° 8.00mm> <@ 37.50 QZ (MS selvage) Vein 20.00° 2.00mm> <@ 37.80 QZ-MO-PY Vein 30.00° 12.00mm> < 38.20 MS-MG clots, CL Fracture 60.00° 9OO........57.7O_Diorite I Dark grey, medium.grained diorite. Core competency is poor to moderate. Alteration obscures the crystalline texture of diorite. Core is weakly magnetic in patches, Inferred to be secondary MG in the matrix. MS and MS-CL alteraticos. — QZ veins with strong MS selvages, locally coarse MO. Fracture-coating PY-CP-MO. a Alt of FP, BI, & HB phenos Chlorite 3.00°sa Vein selvages Seilcite 2.00*55 Patchy alt of matrix & mafic phenos Magnetite 2.00°a so Dominantly as fracture coatings Pyrite 1.00%s a Chalcopyrite 0.1%a a Smears on fracture planes Molybdenite O.01%s e 50.70- 54.90 Chalcopyrite 0.30%a a Pyrite 0.10%a a Molybdenite 0.10 <@ 39.10 MS-PY coating Fracture 80.00° 10.00mm> <@ 39.20 QZ.PY-CP.MG Vein 60.00° 7.00mm> — I— I,— II— /1 5,, I— ‘I I— I— ,J.* I— I— I, I— I— I,— ‘I I4 \9o 39.90_ 4Q.0Q t09.. G0a00555 253_ L__ Q.095 40.09_ 4t0L t09_ G0800656 328_._ 6___ <9.995 4t09_ 42.09 t09_ c30800557 312_ 8.._ <0.90S 42.09... 43.09.. G0800558 510. 22.. 0...009.. 43.09_ 44.09_ tOO_ G0800559 2Z2.__ 8_____ 9.908 44.09_ 49.99_ 1QQ_ G0800560 338__. L___ <9.9Q8 45.09... 45.SL 1.90_ G0a00561 214___ 5__.__ <Q.995 46.QQ_ 41.00.. 1.90_ G0800562 521___ 6_____ cO&Q8 4Z.OQ_ 4L00 tOQ_ r °542_ 2L_ <9.tIQS 49.09_ 49.99 LOL I 385_ 29_ <it.995 4.LOIL 49.09.. 1.90 G0800565 49.90_ S0.OL LOL. G0800566 55L_ 131_ <Q.995 59.90_ 51.00.. L09_ G0800567 399_ 5 <0.905 St00 52.0 L0D 080055L 291 20 9.09L 2008111103 Equity Exploration Consultants Ltd. *graphiclognottoscale — Page 2ofll 52.0L 5Q0- 1.00 662 314 0.007 < 39.60 PY-MO Fracture 85.00°> <@ 39.90 QZ-PY Vein 20.00°> <@ 40.30 PY Fracture 50.00°> <@ 40.50 Slickensides of QZ-MS Fault 35.00°> @ 42.10 QZ-PY Vein 50.00° 2.00mm> <s 42.10 MS Fracture 40.00°> <@ 42.80 QZ-PY (MS selvage) Vein 35.00° 8.00mm> <@ 43.20 QZ-PY-CP-MG Vein 50.00° 8.00mm> <s 43.25 PY-MS-coated Fracture 85.00°> <@ 43.50 MS-PY-CP coated Fracture 80.00°> <il 44.00 QZ-MG-PY Vein 50.00° 20.00mm> <@ 44.30 QZ-MS-PY Fracture 60.00°> @ 44.50 QZ-PY-CL Vein 95.00° 8.00mm> <e 45.00 MS-Q2-EP Fracture 45.00°> <sgl 45.60 MS-coated Fracture 70.00°> @ 46.00 QZ.MS Vein 30.00° 7.00mm> <@ 46.90 CY Fault 20.00° 2.00mm> <c 47.60 QZ (MS selvage) Vein 65.00° 4.00mm> @ 48.00 PY-MS Fracture 8.00°> <( 48.10 QZ-MG.CP-PY Vein 65.00°4.OOmm> 48.40 CV Fault 89.00°> <@ 49.20 MO.PY Fracture 85.00°> <@ 49.30 QZ-CP.MO Vein 80.00° 25.00mm> <@ 49.70 QZ -MO-PY Vein 75.00° 10.00mm> <@ 51.10 MG.HE Fracture 30.00°> <@ 51.25 QZ-CP.PY Vein 70.00° 3.00mm> <@ 51.80 PY-CP coated Fracture 50.00°> <@ 51.85 QZ-PY Vein 75.00° 3.00mm> <@ 52.40 QZ-FP-MO (margins)-PY-CP (centre-flll).MS Vein 87.00° 15.00mm> <@ 52.55 QZ-MO-PY-CP (centre fill) Vein 50.00° 15.00mm> <@ 52.60 PY-CP Fracture 60.00°> <1ff 52.80 PY Fracture 70.00°> <@ 53.50 QZ-MG Vein 40.00° 8.00mm> <@ 53.60 MO-PY-CP Fracture 80.00°> <@ 53.90 QZ-PY-MO Vein 70.00°-10.OOmm> <@ 54.35 QZ (MS selvage) Vein 85.00° 12.00mm> <@ 54.50 PY Fracture 85.00°> <@ 54.80 QZ Vein 40.00° 10.00mm .< ct 55.00 QZ (MS selvage) Vein 90.00° 5.OOmm2..... Project: Taseko Hole Number: O8TSK-02 — From To Rock-type & Description Cu Mo AuFrom To Wth Sample 3 0 3 3 3 0 4 0 4 0 45 — 0 44 0• 6300 54fln Inn nanncn 36 0 006 54.OQ_ -5500 LQQ_ G0800571 415 10_ co.0Q5 55.00_ Ss.00 1.00_ G0800572 410 1I_ <0.005 S5.00_ SLZtL t70_ G0800573 ‘8L 21_ <0.Q0S\ 50_ I, 1/ I,— // ‘-4, II I,— // II— II // I,, I, I’’, I, 4ti, 55 2008111103 Equity Exploration Consultants Ltd. *graphic log not to scale Page 3 of 11 ‘It, II // II , I, II ‘II Project: Taseko Hole Number: O8TSK-02 From To Rock-type & Description / From To Width Sample Cu Mo Au - ppm 40 <@ 51.25 PY-CP Fracture 70.000> <i 51.65 QZ-PY Vein 20.003. 0mm> 57.70 60.40_Breccia - Hydrothermal(?) I Dark grey to black breccia. Moderately to strongly magnetic. Locally clasts of diorite and truncated QZ veins. Clasts have sharp margins and can be irregular Inform. Strongly CL-altered. Fracture-coating PY common. a Alteration of dlorite clasts Chlorite 3.00*00 a Biotite 3.000,, mg aPyrite 2.00%oo 00 Chalcopyrite 1.00%a Magnetite 3.000,, <@ 58.14 PY.coated Fracture 50.000> <o 59.20 Pyrlte.coatlng Fracture 90.000> <i 59.10 Fracture 90.000> fl4fl SRA AndAmitm L70_ 581L 100_ G0800574 77 SL_ 0.005 8.70_ 61L40_ j7Q_ G0800575 ‘S 21___ 0.008 Fine-grained black rock. MG-BI alteration. Core competency Is poor. High density of fractures, no preferred orientation. Rock is moderately magnetIc. Fracture-coating PY-CP. sAlteration of matrix Magnetite 3.00*,, a Biotite 3.00*,, a Chalcopyrite 0.75%,, o Pyrlte 2.50% <@ 60.40 Fracture 30.00’> <i 60.70 QZ Vein 60.00* 20.00mm> Sn *10 6580 8670 Dioritm SI Afl SI *10 I no 57 An 5 An 0 0. 0 5 0 -I--- I flfl Ifl5flflS7S ARC C2 An I flfl tnsnne77 a,s 9*1 Si— 45 40 5 I n 005 flnsnnc7a goq as 0, 4 n floe 64.40 I0 flnQnnc7a 2II 65.40 en one 1.00 G0800581I 594 8 0.006 Greenish-grey, medium- to coarse-grained diorite. Core competency Is good. Large zoned PF phenocrysts. CL after BI and HB. Matrix has a strong green tinge - imparted by CL QZ stockwork veining (typically <Ito 20 mm, 20-40 to core axis). QZ veins with CL infills (after MG?). PY occurs as fracture-coatings, with trace CP. 10 — o Chalcopyrite 1.00%so Pyrite 2.00%s a With PY-CP Quartz Veining 3.00°oos Chlorite 3.00’s <@ 66.50 QZ-PY Vein 20.00’ 5.00mm> <c 66.80 PY Fracture 25.00°> <@ 68.80 QZ-MO Vein 75.00’ 25.00mm> 75 — <c 68.85 MS-MO Fracture 70.00’> —1 00 5&40_ 65.OQ_ .5Q_ G0800582 SQL_ IL__ 0.005 88.QQ_ 6LtI0_ 100_ G0800583 tSZ__ 30___ 0.00S 4L00 6500 100_ G0800584 0L_ 14___ &1I5 Z.QP 6.00_ t00_ G0800585 58.00_ 69.tIO_ 100_ G0800586 243_ 49_ D.005 59*00_ 70.00_ I00_ G08005s7 4I._ 31_ 0.0Q5 Z0.00_ Zt00_ 100_ G0800588 468_ 28L_ 0.0Q5 Th00 Z2L 100 006 Z2.QL 73.00_ 100_ G0800590 25L_ W___ 0.0Q 23.00 Z40 100 G08005i 3i9 4 Z400.. Th..0L .1.0L G0800592 309_ 29_ 0.01l5 71.00_ 7SQL 100_ G0800593 278_ 2L_ tLQQS 75ll_ 77QQ_ jQQ_ G0800594 542 21_ Q.00L ??.0L Z8.00_ j0Q_ G0800595 501_ 6I__ 0.SQL 00 Z9L I0Q G30Q 311 6L 05 2008111103 Equity Exploration Consultants Ltd. *graphiclognottoscale Page 4of 11 <@ 70.60 QZ-MO (margins) Vein 80.00° 1.00mm> <@ 71.00 QZ-PY-CP Vein 20.00° 15.00mm> <@ 72.40 QZ-CL Vein 75.00° 3.00mm> <@ 74.90 CY-rlch Fault Gouge 85.00° 60.00mm <@ 75.30 QZ-PY Vein 50.00° 20.00mm> <@ 75.30 MO Fracture 85.00°> <@ 77.70 MO-MS Fracture 86.00°> <@ 78.10 QZ-MO Vein 78.00° 20.00mm> <@ 79.45 QZ.CP-PY Vein 80.00° 10.00mm> <@ 79.80 QZ-PY Vein 2000° 30.00mm> <@ 80.20 QZ-PY (MS halo) Vein 85.00° 8.00mm> <i 81.40 QZ-CP-PY Vein 70.00° 15.00mm> 85 — 86.70 101.00_Andesite I Dark grey to black, altered andesite(?) with possible phenocrysts. Core competency is poor. Possible fault zone as core is so rubbly? Rock is weakly magnetic, black colour due to secondary BI? Locally intense MS and CY alteration around veins. Mineralization is focused in veinlets < 1mm wide. PY-CP are the most common suiphides, locally disseminated In host rock. 90 — s 86.70- 90.30 Biotite 3.00°ss 90.30-101.00 Biotite 2.00°se Magnetite 2.00°ss Pynte 0.06%es 86.70- 90.30 Chalcopyrite 0.50%ass 90.30-1 01 .00 Chalcopyrite 0.10%oo< 86.70- 95.70 Chlorite 3.00°es 95.70-101.00 Chlorite 2.00°ss Quartz Veining 3.00°s <@ 90.30 QZ-PY-CP-MO (MO at margins) Vein 50.00° 20.00mm> <@ 91.20 CY-rich Fault Gouge 30.00° 10.00mm> <@ 91.75 QZ-PY-CP Vein 20.00° 13.00mm> <@ 92.35 QZ-PY Vein 45.00° 5.00mm> <@ 92.30 HE-CY Fracture 60.00°> <@ 92.70 CY-nch Fault Gouge 40.00° 30.00mm> <@ 93.00 QZ-PY-CP Vein 70.00° 12.00mm> <@ 95.80 QZ-PY.CL Vein 46.00° 5.00mm> <@ 96.30 PY-MO Fracture 10.00°> <@ 97.70 QZ-PY Vein 75.00° 5.00mm> <@100.50 QZ -FP-PY Vein 15.00° 5.00mm> <@100.60 QZ-PY Vein 70.00° 4.00mm> 101.00 169.10_Diorite I — Project: Taseko Hole Number: O8TSK-02 From To Rock-type & Description j From To Width Sample °pm Om pi 053 0 3 0 0.510 5 0 4 0 4 0 4 40 — 7onn nnnn inn flnRnnKo7 ‘C efl nnc 4 I, // €2 ‘1 €2 /1 LSQ 404 005 iQQ 82Q0 tQQ 31S 2 2.l_ 62gQ_ t0_ G0800600 254__ 13_ Q.GQ5 Q_ 14.QQ_ tQQ_ G0800601 2986_ 46___ Q06_ 4,0Q_ 85QQ_ tQS_ G0800602 334__ $._ Q006 6.0Q.. 86.QQ_ L00_ G0800603 50L_ 3L_ Q.QOL S.0_ 8LS_ tS_ G0800604 36__ 12___ <0.005 87,S0 i00 Q5P050L Z.QQ_ 85.0Q_ iQ0_ 130800606 51L_ 142_ <0.005 LOD_ 80.00_ i00_ 130800607 112i_ <0.OQS S.QL 90.00... 1.QL_ 130800608 84L_ 216_ 0.05L SQ.0L 9t00_ LQ0. 130800609 1150_ 20&_ 0.QQ5_ 81.0Q_ 92.00_ t00_ 130800610 764__ 5j_ <0.0Q5 52.Q0_ 93.0Q_ tQL 130800611 66L_ 3L_ OOQL 83.00_ 94.Q0_ i00_ 130800612 56L_ SL_ Q.QGL 4.0tt_ 96.Q0_ I.0L 130800613 475_ 3L_ 0..QQL 85.QL 96.00_ 100__ .GQ500614_ 922_ 328_ 0.QQL 55.0L 97.00_ i,00._ 130800615 96L_ 924_ 000L 57.0L 96.0Q_ tO0._ 130800616 105Q_ 82__ 0.QQL 58.0L 99.00. tQ0._ 130800617 862_ SL_ 0.OQL 9,00_ 180.00 1.QL 130800618 755_ WL_ 0006_ i0Q.80 IGLOO LQL 130800619 61L.... 74__ <0.006 95 — 100_ \- \r° iG1.S0 IGLOO Q.00_ 130800620 2008111/03 Equity Exploration Consultants Ltd. °graphiclognottoscale Page Light grey-green diorite, core competency is moderate to poor. Large <10 mm PP phenocrysts. CL alteration of BI and HB phenocrysts. Several generations of QZ veins cross-cut each other. Large (>10 mm) veins have MS alteration selvages, bleaching the unit. QZ-MO veins. — a 101.00- 156.10 pervasIve Chlorite 3.00°ee 156.10- 169.10 Chlorite 2.00°a<s 155.30- 169.10 Biotite 2.00°cc 102.70- 105.50 On fractures Chalcopyrite 0.10%cc 112.00- 128.00 In QZ veins Chalcopyrite 0.10%aa 102.70- 105.50 Magnetite 1.00*ca 112.00- 128.00 Molybdenite 0.03%,,a 129.00. 133.40 Molybdenite 001%ca 137.20- 142.60 Molybdenlte 0.05%aa 155.30- 155.90 Molybdenite 0.01 %aa 156..?.— 169.10 Molybdenite 0.02%uv 101.00- 105.50 Pyrite 1.00%ea 105.50- 169.10 Pyrite 0.01%a a 109.00- 110.39 Quartz Veining 2.00°ss a Quartz Veining 3.00°c <@102.50 QZ-PY-MG-CL Vein 15.00° 10.00mm> <@104.80 MS Fracture 60.00°> 015... <@105.20 QZ-PY-CL Vein 85.00° 30.00mm> <@105.45 PY-CP Fracture 65.00°> <@106.20 QZ-PY-CL Vein 90.00° 35.00mm> <@107.00 QZ-CL (MS selvage) Vein 40.00° 20.00mm> <@105.50 CY-rich Fault Gouge 40.00° 40.00mm> 120 <@109.05 QZ-CL Vein 45.00° 4.00mm> — <@109.90 Dominant orientation Fracture 50.00°> <@110.70 OX-MG Vein 20.00° 9.00mm> <@113.60 QZ-CL Vein 60.00° 3.00mm> <@113.70 QZ-PY Vein 65.00° 3.00mm> <@114.30 QZ-PY-MO Vein 80.00°40.OOmm> 125 <@116.20 PYVein 110.00° 1.00mm> <@117.10 Qz-PY-MS Vein 50.00° 40.00mm> <@117.50 Qz-PY-MO Vein 40.00° 60.00mm> <@121.05 QZ Vein 80.00° 6.00mm> <@121.30 QZ-PY-MO Vein 60.00° 10.00mm> ioo_ <@123.20 OX-MO Vein 60.00° 25.00mm> <@124.00 QZ-MO-PY-CP Vein 60.00° 50.00mm> <@125.00 QZ PY.MO Vein 70.00° 60.00mm> <@126.40 OX-MS Vein 30.00° 5.00mm> <@127.30 QZ.CP Vein 85.00° 3.00mm> <@129.30 QZ-PY Vein 70.00° 8.00mm> — <@131.30 OX-MG Vein 40.00° 3.00mm> .< @ 131.60 OX-MO Vein 70.00° 50.00mm> 2008111103 Equity Exploration Consultants Ltd. Project: Taseko Hole Number: O8TSK-02 Cu Mo AuFrom To Rock-type & Description j From To Mdth Sample 0. 0 5 0 40 G0800621 554 43 I 0.006II II I, 7/— /1 /7% 1/ /7 ‘I— II II II 1/ /7 /7 “1 // I K” /7 // K” // 102.00 103.00 100_ 00800622 28L 15. <0.000 103.00 104.00 t00_ 00800623 615_ 6L_ 0.005 404.00105.90 tl0. 60900924. 5.05. l 0.005. 104.00 105.5.0 1.50_ G0500625 105.50 107.00 L50_ 00800626 60L 37 0.OOL 105.00105.00 t00 60800527. 497 10 0.005. 109.05 110.00 t00_ 00800628 334 L Q.00L 110.05 111.00 t00_ 00800629 34L_ Z 0.005. 111.05 112.00 t00_ G0800630 34L_ 1L_ 0.055. 112.00 113.00 t00_ 00800631 80L_ L__ 0.005. 112.05114.00 t00 60000632. 440 32_ <0.009 114.00 115.00 t00_ 00800633 ‘.4L_ 0L__ Q.005 115.05 11.0Q tO0. 60900635. Z1 13 00 115.00 117.00 L0Q_ 00800635 11L 4.. <5.05.5 IILOO 114.00 t00_ G0800636 52 2L 9.005. 114.05 115.05 tOO_ 00800637 3Di L_. 9.005. 115.05 120.00 t00_ G0800638 16L t 9.005. 125.00 121.00 1.0Q_ 00800639 57 L 0.011. 121.05 122.00 tOL 00800640 caj 294 0.007. 122.05 123.00 t00_ 00800641 185_ 1L_ 9.505. 123.05 124.50 t00_ 00800642 0.L_ °L_ 9.005. 124.00 125.00 t00_ 00800643 243_ 1L_ 0.005. 125.05 125.00 t00_ 00800644 37L 5L 0.005. 125.00 126.L0 L00_ G0800645 125.00127.00 t00 60000045. 7A5 74_ 0.017. 127.05 125.06 t00_ 00800647 69L 55. 0.511 125.00 129.50 1.0L G0800648 392. 1L_ 0.505. 129.00 130.5Q t00_ 00800649 795. 23. 0.505. 130.00 131.50 t00_ 00800650 343_ 5.__ 0.007. 131.05 132.00 t00_ G0800651 415_ 4&_ Q.50L 132.05 133.55 t00_ G0800652 40L_ __ 9.505. 133.00 134.55 t50_ 00800653 SSL 15. 00L 134.00 135.00 1.00_ G0800654 5.52_. L_ 5.012. 135.05 136.90 t00_ G0800655 594 192 0.022. 135.00 137.00 t00_ 00800656 864 52 0.025. 137.00 138.00 t00_ 00800667 8.SL 29 0.03 134.05 139.00 1.90_ G0800658 41L -31 0.005. \ \cS° of \of 1° 4— 00 C 11000 14000 100 nRnnscq IRS 0007 °graphic log not to scale Page 60th <@144.40 QZ-PY-CL Vein 20° 2.00mm> <@151.70 QZ-PY-CL Vein 65.00° 20.00mm> 169.10 197.00_Breccia - Hydrothermal(? I Dark-grey to black, medium- to fine-gralned breccia. The decrease in grain si0170 — is due to alteration, obscuring the original igneous texture. Core competency is moderate. Dionte clasts dominate, with andesite and QZ vein fragments. BI alteration obscures some of the PF phenocrysts. QZ-PY and rare MO veins. QZ-CL Project: Taseko Hole Number: O8TSK-02 From To Rock-type & Description — — Cu Mo AuFrom To tMdth Sample 0 4 139.00 140.00 1.00 00800660 140_ 145_ 150 155_ 160_ 165_ II I I /1 /7 I I 1 II I 7% I Ii II 7% /1 /1 0 50 0 0 \ \0° \r r \5’ 0 0. 0 5 0 4 0 4 0 4 0 140.00 14tQ tQQ_ 00800661 4j5_ 44_ Q.O1L i4 t0Q O6QQ55 151 2Q4 QQL 142.00 143.Q L0L 00800653 495__ 7___ Q.QOL I4.9Q 144.Q t00_ 00800664 323_ 1L_ <Q0Q5 j4399 j44Q 19Q_ 00800668 j44.QQ j45.fl 1JQ_ G0800666 195__ 3___ 0..005 I4S.0O 145.Q 1g 00800667 243_ 7__ %Q05 14590 14Z.Q L0L 00800658 ‘595_ 22_ <0.005 i4LQ L00 Q50Q65L 54 5 i45.QQ 149.Q 1.9O G0800670 35i_ L_ <Q.P5 i4 t 040Q57t 165 ‘1 9Q5 isc ThI L90 QS0O5ZZ IZL Q0L 151.60. t52.Qf tOL 00800673 241__ 39_ Q6QL 152.60. 151.9 L0L 00800674 410_ 5___ Q.00L 151.60 154.00. L9L 00800675 0Q_ 4___._ <.6.905 154.60 155.00. G0800676 25 1.2__ 0.065 155.QQ 155.90. 100_ 00800677 t33_ ‘t___._ <0.095 155.00. 15L00. tQQ 980Q5Z5. 153 17_ <0.005 ISZ.00. 155.00. 100 00005l 181 <0.905 j55.0Q 155.00. 1.0L 00800680 t6L_ 0L___ <0.095 155.00. 160.00. tQL 00800681 167__ ‘L__ <9.096 16Q0Q 151.00. 1.0L G0800682 IOL__ __ <0.096 15L00 162.60. 1.00_ 00800683 ‘.30__ 15__ <9.096 182.90.165.00. L0Q 04005 10L 18L <0.095 .142.60. 163.00. 1.00_ 00800685 143.00 144.00. 1.0Q_ 00800686 31._.. __ <0.095 164.00. 1459k 1.00_ 00800687 195.__ 15__ <00Q5 165.0Q 164.00. 1.00_ 00800688 ‘.24__ 14_ <9.0Q6 164.00. 167.00. t90_ 00800689 111__ 10__ <9.006 ISLQ0. 165.00. t00_ 00800690 99_ q %OOL 165.00.165.00. t00 950086I 429 c4 <9.096 149.00 170.00. 1.09. 00800692 107L 3___ <0.006 170.90.171.00. 1.00 0860685. Z4 <0.005 17i00 172.00. 1.0L 00800686 -145 t____ <0.095 172.00 173.00. t0ft_ 00800695 t14_ 15__ <9.Q95 173.00 174.00. 1.00_. 00800696 414_ 5__ <9.096 174.00 175.00. 1.0L 00800697 177_ 66_ <9.005 2008111103 Equity Exploration Consultants Ltd. *graphic log notto scale Page 7of 11 ‘Op Project: Taseko Hole Number: O8TSK-02 From To Rock-type & Description From To Width Sample pm p°m p 0 3 0 0.50 0 40 339 12 <0.005veins are also common. Dominant vein orientation is 70-80 to core axis. ° 5° 175_ a 169.10- 170.10 Replacing PF & mafics Sericite 3.00°ca 183.80- 184.10 bleached IrS appearance Sericite 4.00°ca Of andesite clastslmatrix Biotite 2.00*55 Pervasive Chlorite 3.00°a5< in QZ veins Molybdenite 0.01%aa Pyrite 0.30%a <4 169.10- 170.10 Chalcopyrite 0.10%o o< 184.90- 170.75 patchy Magnetite 3.00°c loo_ <@169.30 QZ-MO-PY-CP Vein 65.00° 80.00mm> <@169.50 Fault Gouge 15.00°> <@170.20 CY-rich Fault Gouge 85.00° 50.00mm> <@172.60 QZ-PY Vein 87.000> <@176.70 QZ-PY Vein 85.00° 15.00mm> 185_ <@178.90 QZ-PY-MO Vein 80.00° 10.00mm> <@182.50 QZ-MO Vein 85.0020.00mm> <@189.90 QZ-CL Vein 75.00° 40.00mm> <@191.60 QZVein 80.00°4.OOmm> 190_ 195_ I9ZAL...219.OO_Breccia - Hydrothermal(?) I Black, fine.grained breccia with clasts of diorite. Core competency is very good. Moderately to strongly magnetic; MG-Bi alteration. Clasts of diorite in the fine.grained material are CL-altered. QZ veins crosscut the unit, — 50 mm 000_ spacing. Locally finely disseminated sulphides; distribution not consistent. QZ-CP-PY veining. a 212.60- 214.00 Broken core with gouge material Fault Zone cc Quartz Veining 3.00°ooo< Proximal to veinslin matrix Chlorite 2.00°e<i Biotite 3.00°c*< Pervasive Magnetite 3.00°ea Disseminatedlin QZ veins Pyrite 2.00%oia Chalcopyrite 1.00%g_ <@198.00 Fault Gouge 87.00°> <@198.00 CY-rich Fault Gouge 87.00° 50.00mm> <@200.36 QZ-PY-CP Vein 75.00° 35.00mm <@202.30 PY-CP Vein 70.00° 3.00mm> — I I 179.00. 171.00 100_ G0500699 581..... 5........ Q.Q05. lTh00. ff7.00 0.00 0400700 177.00.178.00 100 95QQ70t 48Z Si 0.000... 178.00. 179.00 1.00.... G0800702 392.... 24 0.000. 179.Qft 190.00 100.... G0300703 323.... 9__ %005 140.00. 191.00 lOlL. G0800704 ‘Ijl_ 5... 0.009.. 190.00. 141.00 100.... G0800705 141.40. 152.00 100.... G0800706 142..... L......... 0.005 142.00.183.00 100. .00400707 82 S 0.000. 143.00. 144.00 100.... G0800708 ‘14_... !L...... 0.005 184.00. 199.00. .tQ0_. G0800709 59..... IL..... Q.005 145.00.165.00 100 04007iL S01 L Q.0Q5 186.00.167.00 1.00 0400Z11 553 I 0.000. 147.00. 188.00 100 G0500712 459... 5....... 0.009.. 148.00. 189.00 1.00.... G0800713 519..... L......... 0.008. 149.00. 190.00 100_ G0800714 57L 19.... 0.OQS 190.00. 191.00 100.... G0800715 404 29........ 0.005.. 140.00.192.00149... 080Q71L 140 14 192.00. 193.00 100 G0300717 4L_ Q.0QL 193.00. 194.00 lolL. G0800718 829. I.4......... 0.005.. 194.00. 195.00 lOlL. G0500719 .599.... 64........ Q.OO9. 195.00. 196.00 100... G0800720 4L 9.405. 195.00. 147.50 i5L.. G0800721 149.... L......... 0.009. 197.50.115.00 0.50 0800Z2L 149. 1 0.009. 198.00. 199.00 lOlL.. G0800723 599.... 1........... 0.006. 199.00. 200.00 1.O0 G0800724 q1s.... 5___ 0.01_ 199.00. 200.00 1.00.... G0800725 200.00. 201.90 1.00.... G0800726 869.... 7...... Q.00Z 20.t00. 202.00 100 080OZ2L 795 19 0.00L 202.00. 203.00 1.00... G0300728 605.. 4........... 0.006. 203.00. 204.00 1.00.... G0800729 462 6............ <0.005 204.00. 205.00 1.00... G0800730 309... 9........... 0.005. 205.00.206.00 100 Q8Q0Z3i 649. 65 0.007. 206.00. 207.00 1.00... G0800732 399.... 109..... 0,005. 207.00.208.001.40... 0800Z3L 520 14 0.005 208.00. 209.00 1.0L_ G0800734 1411... 41........ Q.0.L.. 209.00. 210.00 1.00.... 40800735 687..... 219...... 9..005. 210.00. 21100 100.... G0800736 629.... -32_...... 0.005. \cf 00 t’) 2008111103 Equity Exploration Consultants Ltd. °graphiclognottoscale Page Page 9ofll Project: Taseko Hole Number: O8TSK-02 From To Rock-type & Description / , ‘ From To Width Sample Cu Mo Au _______ ppm ppm ppm <@202.50 CY-rlch Fracture 60.00°> 210 0 50 3 0 05 0 5 < 0 0 <@208.60 QZ-PY (CL selvage) Vein 80.00° 4.00mm> >3’ <@208.78 QZ-CP Vein 50.00° 25.00mm> <@214.70 QZ-PY Vein 57.00° 25.00mm> <@215.10 QZ-PY-CL Vein > <@215.50 QZ-CP-PY Vein 90.00° 3.00mm> 215 <@217.70 QZ-PY-CP Vein 85.00° 20.00mm> 224.00_Diorite Medlum-grained, porphyritic diorite. Core competency varies from poor to J moderate. Fingers of breccia less than 20 cm. Pervasive MS-CL alteration. 220 QZ-PY.CP stockwork with MS selvages; MS alteration is most Intense proximal to stockwork veining. \h0 <@221.07 QZ-PY Vein 60.00° 3.OOm> / <@224.51 QZ (CL selvage) Vein 40.00° 5.00mm> <@223.15 CP-PY Fracture 40.00°> os Pervasive Chlorite 3.00°coms 3.00°cs< Chalcopyrite 0.30°hc so 0.1 Pyrite /i 0.10%ss 245.00_Breccia - Hydrothermal(? Dark grey to black breccia. Matrix is fine- to medium-grained almost 225 aphanitic in places (where alteration obscures the igneous texture). Clasts ct< dominantly altered diorite. QZ veining throughout, some with PY and CP. QZ dominant veins with trace PY are cross-cut and offset by QZ-PY-CL veins. \ Strongly to moderately magnetic, rock appears to be composed of comminuted ro fragments. PY-CL veins are the most abundant vein-type. 4S c °2*’ \° c Chalcopyrite 0.50%c os Pyrite 1.50so Biotite 2.00°c c Chlorite 3.00°c c Magnetite 2.00*5 C Molybdenite 0.05%c <@225.10 QZ-CP Vein 70.00° 4.00mm> -, 235 -8 <@225.25 QZ-PY-CP Vein 60.00° 4.00mm> <@228.40 QZ-CP Vein 70.00° 9.00mm> <@231.10 QZ-CP Vein 70.00° 10.00mm> <@235.10 QZ-CL-PY Fracture 80.00°> °21 \ < 236.60 QZ-PY Vein 60.00° 20.00mm> 2008111103 Equity Exploration Consultants Ltd. °graphic log not to scale Project: Taseko Hole Number: O8TSK-02 From To Rock-type & Description 1 . Cu Mo Au‘ From To Width Sample . .__k ppm ppm ppm < @ 240.25 QZ-PY-MS Vein 85.00° 20.00mm> 240 0 50 0 0 0 0 0 5 4 IS 4 0 4 0 5 0 4 240.00 241.00 1.00 G0800769 1005 63 0.007 < ct 243.40 QZ-PY Vein 70.00° 5.00mm> 241.00 242.00 1.00 G0800770 637 108 <0.005 °°5 \‘ 242.00 243.00 1.00 G0800771 1050 104 0.013 \10° ,( 243.00 244.00 1.00 G0800772 1085 112 0.011 \oo° 244.00 245.00 1.00 G0800773 616 94 <0.005 245.00 304.20_Andesite I zs 245.00 246.00 1.00 G0800774 414 22 0.005 Fine-gralned, aphanitic In places. Moderately to strongly magnetic (MG-BI 1 246.00 247.00 1.00 G0800775 321 8 <0.006 alteration). QZ-PY-CP-MO veins (sulphides minor) with MS selvages, typically 2 . J \,c$5° 247.00 248.00 1.00 G0800776 704 43 0.006 to 15mm wide and 60-80 degrees TCA. 248.00 242.00 1.00 G0800777 754 106 0.007 ‘. 249.00 250.00 1.00 G0800778 1015 34 0.007 o 280.25- 280.50 Igneous texture destroyed, bleached Silicification 4.00°ooi \,°‘ 250.00 251.00 1.00 030800779 1185 48 0.011 Pervasive overprint Chlorite 2.00°eso Secondary in clasts Biotite 2.00°ae IS 251.00 251.00 0.00 030800780 Alteration of clasts Magnetite 3.00°c 44 Chalcopyrite 0.50%ss 44 Pyrite 1.50%ss c : 251.00 252.00 1.00 030800781 900 32 <0.005 Molybdenite 0.10%uso 245.00- 258.50 Chalcopynte 0.30%sos 262.50- 269.40 : 252.00 253.00 1.00 G0800782 664 29 <0.005 Chalcopyrite 0.10%soo 269.40- 276.00 Chalcopynte 1.00%ou 298.10- 304.20 253.00 254.00 1.00 030800783 617 141 <0.005 Chalcopynteo.10%o 254.00 255.00 1.00 030800784 961 106 0.009 zoo I 254.00 255.00 1.00 00800785 <@245.60 QZ-CP-PYVein85.00°5.OOmm> 255.00 256.00 1.00 00800786 886 60 0.006 < @ 245.60 CY Fracture 75.00°> ° 256.00 257.00 1.00 (30800787 1650 149 0.01 < @ 247.10 QZ-MG-CL Vein 60.00° 3.00mm> 257.00 258.00 1.00 00800788 782 88 0.005 < @ 247.60 QZ-PY Vein 78.00° 6.00mm> ;_i 258.00 259.00 1.00 00800789 496 37 <0.005 < @ 249.85 CL Fracture 55.00°> 264 - 259.00 260.00 1.00 (30800790 1540 64 0.006 < @ 256.60 PY Vein 80.00° 5.00mm> . :. 260.00 261.00 1.00 00800791 513 12 <0.005 < @ 257.10 PY-QZ Vein 4.00mm> ,_ 1 261.00 262.00 1.00 00800792 887 79 0.005 < @ 257.80 CL Fracture 89.00°> . \ 1 262.00 263.00 1.00 00800793 1165 69 0.008 <@258.85 aZ-CL Vein 70.00°30.OOmm> 263.00 264.00 1.00 G0800794 570 61 0.005 < 259.30 CL Fracture 80.00°> I 264.00 265.00 1.00 00800795 568 109 <0.005 < @261.43 QZ-PY Vein 75.00° 17.00mm> 1 I 265.00 266.00 1.00 00800796 716 68 <0.005 < @ 262.07 PY Fracture 50.00°> 266.00 267.00 1.00 (30800797 677 30 <0.005 < @ 262.30 QZ.PY Vein 70.00° 30.00mm> 267.00 268.00 1.00 00800798 333 51 <0.005 < @ 262.50 QZ-PY-MO Vein 45.00° 70.00mm> 268.00 269.00 1.00 00800799 668 71 0.005 < @ 263.70 QZ-PY Vein 80.00° 20.00mm> .. 269.00 270.00 1.00 00800800 826 84 <0.005 <@264.06 PY Fracture 70.00°> 270 \j10’ 270.00 271.00 1.00 G0800801 910 49 0.005 <@264.20 QZ-PYVein56.00°10.OOmm> . 271.00 272.00 1.00 030800802 644 32 <0.005 < @ 264.80 QZ-CP-PY Vein 75.00° 35.00mm> ., 272.00 273.00 1.00 030800803 903 141 0.005 < @ 269.40 QZ Vein 78.00° 25.00mm> \‘ 273.00 274.00 1.00 G0800804 380 12 <0.005 < @ 269.50 CP-CL Vein 90.00° 4.00mm> 273.00 274.00 1.00 00800805 < @ 270.25 QZ-MS Vein 70.00° 8.00mm> ,- : - “°““°“““ °°°‘°“°“° f’ n,’° 2008111103 Equity Exploration Consultants Ltd. *graphiclognottoscale Page lOofil00 <@280.00 CL Fracture 80.00°> <@271.00 QZ-CP Vein 50.00° 10.00mm> <@273.06 QZ-CP-PY Vein 65.00° 20.00mm> <@276.30 Qz-CP Vein 75.00° 40.00mm> <@276.90 QZ.CP.PY Vein 87.00° 5.00mm> <@277.80 QZ Vein 50.00° 50.OOm <@278.30 PY-CL Fracture 4.00°> <@281.70 QZ-PY Vein 80.00° 5.00mm> <@282.40 PY-CP coating Fracture 75.00°> <@282.80 QZ-MG Vein 45.00° 40.00mm> <@283.30 QZ-CP Vein 86.00° 6.00mm> <@283.50 QZ-CP-PY Vein 55.00° 30.00mm> <@287.40 QZ-Ep Vein 75.00° 3.00mm> <@293.10 QZ-MG Vein 5.00° 5.00mm> <@295.20 PY Vein 65.00° 2.00mm> <@295.30 PY Fracture 45.00°> <@296.10 QZ-Cl Vein 40.00° 40.00mm> <@296.50 QZ-CL Vein 56.00° 35.00mm> <@298.80 QZ-PY-MG (MS selvage) Vein 65.00° 5.00mm> <@299.10 QZ Vein 65.00° 25.00mm> <@301.90 QZ.CP (CL selvage) Vein 89.00° 20.00mm> <@302.00 CY Fault 65.00°> <@302.50 QZ-CL Vein 70.00° 40.00mm> <@303.20 QZ-PY Vein 60.00° 4.00mm> <@303.90 QZ-PY Vein 90.00° 5.00mm> Project: Taseko Hole Number: O8TSK-02 From To Rock-type & Description j From To Witii Sample Mo Au -- - 5 3 F 0 400 6 5 7S On 7R no i no 82OOARO7 58 n nos \° 280 283.. 200.. 295.. 300 - 278.0 2Th9 t90_ (30800808 782 30i_ 6.05 271.0 278.0 L0Q_ (30800809 680 44_ Q.09S 278.0 2Z941Q. 1.0_ G0800810 53J_ 35___ 0.00_ 278.0 30Q& 1.0Q fl89Q81i °,12 58 296.0 281.0 tDL Q8QO812 85 281.0 282.0k tOQ_ (30800813 475 2L_ 6.005 282.00 283. tOQ_ (30800814 40L 21L_ Q.093 283.00 Z84.0 t98 (30800815 1.02526. 2L_ 6.0S 284.00 285.Q L0Q_ (30800816 538_ 18._ Q.00S 285.00 2li.0 tOQ_ (30800817 79& 44. Q.00L 286.00 287.0 tDQ_ (30800818 42& IL_ Q.00S 287.00 288.0 t2L Q89Q8i9 808 3Q %QQ8 285.00 2I8.J3 0.0Q_ (30800820 285.00 289.0 IJIQ_ (30800821 5Q4_ OL_ 0.005 289.00 290.0 tO_ (30800822 309_ 18._ Q.05 290.00 29t0 tOQ_ (30800823 625_ 3L_ Q.05_ 29QQ 292.0k iO0. Q8QQS24 48L Z7 6.0S 291.0 292.D tDO (30800825 292.0283.00. tOL Q8QQ82L 68L 2L 0.05 293.0 284.00. tDQ_ (30800827 105L 60 0.01_ 294.00 295.00. tOO_ (30800828 1Q80 4L_ Q.OOL 295.0 296.00. tQQ_ G0800829 804 65 Q.01I 296.00 297.00. tlIO_ (30800830 3.07_ 52_ O.00. 297.00 298.00. 1.00_ (30800831 684 4 Q.0Q5_ 298.00 299.00. tO_ (30800832 31L_ 7Q Q.OQt 289.00 300.00. tQQ_ (30800833 !88_ Zt 0fl 30.00 301.00. t0Q_ (30800834 617 28__ Q.009. 301.00 3.02.00. 1.00_ (30800835 I1OL 12L_ 0.09_ 302.0 303.00. t0Q_ G0800836 2200 28L_ Q.OIL 303.00 304.20. t2L. (30800837 t1QL 222_ Q.01t 4041 20 (fl 20 FOH I 00 2008111103 Equity Exploration Consultants Ltd. °graphic log not to scale — — Page 11 of 11 ,A, • EQUITY I EXPLORATIONI CONSULTANTS LTD Project: Taseko Collar elevation: 2192.Om Hole: O8TSK-05 Azimuth: 110.00 Proposed: O8TSK-E Dip: 60.00 Location: 449473 m East 5671695 m North Length: 310.30m Prospect: NW Copper Date started: Date completed: 2008/08/12 2008/08/22 Claim: 354055 Objective: Logged by: L Hollis . To drill acid leach cap exposed on the western flank of Northwest Copper Ridge. Drilled by: No Limit Assayed by: ALS Chemex Core size: HQ/NQ Dip tests by: Reflex MS SUMMARY LOG: 0.0 - 14.6m: Casing 14.6 - 27.4: Andesite. Strong CY-alteration. Fracture-coating FE - 1%. 27.4 - 36.3: Undifferentiated Volcanic. Strong clay-alteration. 36.4 - 54.3: Andesite. Moderate CY-CL-alteration, weak EP. 54.3 - 58.7: Undifferentiated Volcanic. Strong CY-alteration. 58.7 - 139.5: Andesite, minor undifferentiated volcanic. CL-MS-alteration. 0.2% PY. 139.5- 158.2: Andesite. CL-altered. CA-GY + QZ veining. 158.2- 184.5: Undifferentiated Volcanic. CA-QZ veining. 184.5- 218.8: Volcaniclastc. CA-GY+QZ veining. HE on fractures. 0.1% PY. 218.8- 249.0: Andesite. CA-GY veining. CL-alteration. 249.0 - 281.9: Andesite, minor volcaniclastic. CA-veinings. Local MS-alteration. 281.9- 310.3: Volcaniclastic, minor andesite. CA-GY veining. CL-alteration. 0.1% PY. 186 A - I b 4 m o ) r 3 g ) o C -l -< 0) 0) 0) 0) 0) 0) — — b o o iz N P - . 0 0 0 (3 - 0 o o 0 0 0 0 c i I I I 0 G) 0 p CD — . 0 — CD C), 0 CD D) 01 IC fl Cl ) CD ‘S a’ 00 “V “V “V 36.34 45.10_Andesite I Fine-grained black to dark green andesite. Core competence varies -moderate to 37.15 m, where the core becomes crumbly (fragments maximum of 5 cm). Rubbly Project: Taseko Hole Number: O8TSK-05 From To Rock-type & Description j From To Width sample Cu Mo AuEE J ppm 0 40 40 40 40 0 4 0.00 14.60_Casing I 10 — 14.60 21.30_Volcanic - undifferentiated I Core competence is poor - milled rock, with core loss. Bleached rock with FP — phenocrysts. Protolith could be feldspar-phyric andesite. Surfaces coated with fe-oxides. 20 — 21.30 27.45_Andesite I Fine-grained black-dark green andesite? Core is blocky, highly-fractured; poor core recovery. Fractures covered with Fe-oxides. Up to 40% PF phenocrysts, often squat in shape (1 mm). Hard to see igneous texture due to broken nature of core. MInor QZ veinlets. o Fracture-coating Fe 4.00*00 Alteration of FP phenocrysts Sericite 2.00o 0 20 4 [ 1440_ 2L30_ 5.7Q_ G0811370 9L_ 2__ Q.QOL 25 — 27.45 36.34_Volcanic - undifferentiated I Core is bufflcream-coloured and composed of clays and rock fragments. Rock is strongly altered to clays. Can see rare relict FP(?) phenocryst sites. 30 — Fe-oxides are present - imparting orange-colour to core. a Core is CY and rock frags Clay 3.00*0 35 — 21.30 24.40 3.10 G0811371 217 1 0.008 24.40 27.40 3.00 G0811372 195 1 0.006 cc cc 77 tA 20 On 90 On 2 CA 4, Ofl l9 On s nfl snaiism ‘1R7 Sq On 51 On IA0ll17A i nn C IA On 197 ta On A Al Kfl0ll17C 09 I flfl A Al C tiUttll3Ib a’ A A19 fln241177 ‘I, A fllC 2008111104 Equity Exploration Consultants Ltd. tgraphic log nottoscale Page 1 of 12 ,MQ 1.Q0_ G0811378 124__ 5___ 00QL z.3Q__ 39.QQ_ tZQ_ G0811379 14L_ 4__ Q.0i_ Z.3Q 39.QL t7Q 051i3 42.QL 3.40_ G0811381 12L_ 4___ 0005 surfaces. c 45.10- 45.30 Bleached Clay 3.00°c os 45.30- 45.30 Alteration of FP phenos Chlorite 2.00*5 <@ 60.07 FE Fracture 60.00°> <@ 59.80 FE-EP Fracture 70.00°> GO c 60.25- 60.40 angular fragments, CY-rich Fault Gouge Zones ms& m L 01L Page 2of12 from 38.5 to 42 m - fault zone? FP phenocrysts account for —25%. CL+i-EP alteration of phenocrysts. Densely fractured, no preferred orientation. Fractures coated with fe-oxides, impart a rusty discolouration to core. s Chlorite 2.00°c c Epidote 2.00°c s Staining on fracture surfaces Limonite 2.00°c Project: Taseko Hole Number: O8TSK-05 Cu Mo AuFrom To Rock-type & Description j From To V4dth Sample 004 40 — 0 3 0 4 0 4 0 4 0 40 40 4 0 4 45.10 54.30_Andesite I Black andesite, core competency is poor to moderate. Dense fracture network (coated in Fe-oxides) giving core rubbyibroken texture with angular void spaces. Up to 20% FP phenocrysta; CL-altered. Limonite and Fe-staining on most 50 — 40.70 45.10 4.40 G0811382 143 8 0.011 51.20 54.30 3.10 45.10 51.20 6.10 G0811383 113 12 0.013 51.20 54.30 3.10 .54L_58.70_Volcanic - undifferentiated I Orange from 54.3 to 58 m, where colour changes to buff. Rock is strongly — altered. Fine-grained, unconsolidated clay material. Core competence is very-poor, generally clay-sand sized particles in core box. Gouge-like texture; clay-rich. Small rock fragments in gouge appear to be andesite in composition - same volcanic unit as before. 40 Pervasive CY 4.00°c G0811384 90 6 GOSI 1386 0.006 58.70 60.25_Andesite I Core competence is good. Fine- to medium-grained andesite, FP phenocrysts, wit HB (replaced by CL). FP are soft and likely replaced by MS. Phenocrysts are up to 2 mm in size. Dense fracture network, covered with Fe-oxides, gives core a pseudo-brecciated texture. Fe.oxide in the sites of phenocrysts - PY after CL? 54.30 57.30 3.00 G081l386 144 7 57.30 58.70 1.40 G081l3a7 91 5 0.009 0.009 50 — 58.70 60.20 1.50 G0811388 112 9 0.006 60.25 60.94_Volcanic - undifferentiated I Core is strongly clay-altered and bleached in appearance. Core competence is poor. Rock Is gouge-like - fault gouge zone? Similar core consistency to clay-rich zones seen above. \r inqA cn 60.20 63.40 3.20 G0811389 95 12 0.01 2008111104 Equity Exploration Consultants Ltd. *graphic log not to scale Dark grey to black medium-grained andesite. Up to 30% FP (tabular to Irregular In shape) & HB phenocrysts. Hint of a flow texture. MS & CY alteration of FP phenocrysts - now soft. Dense fracture-network, with no preferred orientation, coated with FE; Intensely fractured with FE from 68-69 m. Clots of FE material between 68.96 and 69.36 m weathered from vein material? a Alteration of PF phenocrysts Sencite 3.00°soa Clay 2.00*a < 64.10 CY Fracture 75.00°> <@ 64.26 FE Fracture 70.00°> 69.50 72.50_Andesite I Maroon to dark green clastic andesite. Core competent but highly fractured (no preferred orientation). Phenocrysts of FP (up to 35%) replaced by MS or CY. is — Rare clasts of similar composition andesite. Stringers of HE at 70.0 m (streak red). Paddy areas of FE are common, typically measuring 10-20 mm in diameter. Fractures are FE-costed. Possible veining - now replaced with clay material. s Alteration of mafic phenocrysts Chlorite 2.00°aa FP alteration Sericite <@ 72.35 FE Fracture 10.00°> <@ 72.10 FE Fracture 10.00°> 72.50 73.55_Volcanic - undifferentiated I Sandy-beige, assumed to be similar volcanic protolith to that observed before. Core competency is extremely poor. Core is unconsolidated and has a gougy texture; strongly clay-altered, mm-scale clasts of andesite. Project: Taseko Hole Number: O8TSK-05 From To Rock-type & Description j , From To Width Sample Cu Mo Au - -- 0 54 0 3 0 4 4 4 5 4 0 4 4 4 05.50 L t 64.SQ_ 5Z.5Q tQQ_ G0811393 tlL_ 4___ 0.005 SZ.5Q_ 685L tQQ_ G0811394 134_ 4__ Q.t12_ 64.40_ 89.SL 1,Q_ G0811395 IOL_ 3____ Q.QQ6_ ga_sn 7fl50 ton 70Sfl 7150 71 50 72S0 inn V. Vv VV V. VV VV V. VV VV aon (SnRit’457 66 4 00flg en i 5351511355 SR 1 <n_one 0 0n7 <4 Clay 3.00°a 7Sfl 7255 InC Liusll.sss Z35L_76.O4_Andesite I Black to dark green fine-grained, FP-phyilc andesite (up to 40% FP). Minor flow texture. Core competence Is moderately to intensely fractured -no preferable orientation. Core become blocky and rubbly st 75.4 m. 75 <@ 73.67 FE Fracture 10.00°> 76.04 88.20_Andesite I Dark grey-green PF-phyrlc andesite, core competent. Flne.gralned matrix. Locally rounded clasts. Zones of CY alteration sporadically throughout the .interval (light buff and softer) which are proximal to intense fracturing. un IC tflflflC 74.60 75.60 73.65 74.50 0.95 G0811400 64 <1 <0.005 1.10 G0811401 61 <1 0.005 Th.60_ Z8.40 3.0Q_ G0811402 1Q.4..._ t___ 0.QQ5 Th.6Q_ 9,4Q tQQ_ G0811403 7L_ 3__ Q&0L 79.5Q_ 6QS0 tQQ_ G0811404 73_ Z__ Q.Q05_ 79.5Q_ 6Q.5Q 1.QQ_ G0811405 61_en 1fl0 2008111104 Equity Exploration Consultants Ltd. *grephic log not to scale Page 3of12 Fractures are coated in FE, impart a orange (rusty) colouration to the core. FE stringers are common. Poddy and stringers of HE throughout the interval, 80 - stingers mostly 1 mm wide. o Pods Hematite 0.50%so 78.55- 79.25 Clay 2.00*50 Alteration of FP phenocrysts Sericite 2.00°oo 81.25- 81.60 buff; loss of igneous texture Clay 3.00*00 81.70- 88.20 Alteration of phenocrysts Clay 1.00*5 85 — <@ 82.97 CY & andesite fragments Fault Gouge 60.00°> < 76.10 CV Vein 60.00° 10.00mm> 88.20 91 .70_Andesite I Dark grey to light grey-yellow (changes with depth). Core competency is poor; coherent rock that is crumbly with most forming small angular chips. Strongly clay-altered with relict phenocrysts (assumed to be FP - andesite protolith). QI 7fl lfl A An,i Light grey-green, altered andesite with relict FP phenocrysts. Core competency is very poor; core crumbles on contact and is mostly in rubbly sections. Up to 35% tabular PF phenocrysts. Mafic minerals are strongly MS-ICY-altered. Pervasive CL-MS.CY alteration likely causes the unconolidated nature of the core. Poddy FE from 91.7-94.40 m - weathering of PY? Fracture-coating PY is common. Thin veins of GY-PY - fracture-controlled? o Altered FP Sericite 3.00°x o Clay 3.00*5 a Chlorite 2.00*so 91.70- 94.40 Fracture-coating Pyrite 1.00-2.00%so 94.40- 97.30 Fracture-coating Pyrite 0.50-1.00%oo 97.30- 101.20 As coating & with GY veins Pyrite 0.50-1.00%*oe 91.70- 94.30 pods of rusty alteratIon AlbIte 0.10-0.50%ea Staining with FE Jarosite OiO°a <@ 91.92 GY Vein 45.00° 2.00mm <@ 92.20 GYVein 50.00° 1.00mm> <@ 94.12 GY-PYven 65.00° 2.00mm> <i 97.10 GY-PY Vein 20.00° 1.00mm> <@100.50 GYVein 80.00° 1.00mm> Project: Taseko Hole Number: O8TSK-05 From To Rock-type & Description / From To WkIth Sample Cu Mo AuEE EEL ppm 050 38 40 45 40 48 4 0 4 81.60 82.60 1.00 G0811407 76 1 0.006 62.60_ 83,5Q_ L00_ G0811408 90_ t__ 0.OL 0.S0_ M50_ t00_ G0811409 80__ 1i.._ 0.POL 84.60_ 8S.50_ tOQ_ G0811410 9L_ 4__ Q.005 8S.60_ 65.60_ L00_ G0811411 4t_ 5__ 0.QOL 86L 8L60 LQ Q5114IL 9 4 0QL SLSL 8S.2Q_ Q.SL_ G0811413 t13_ 4__ .00L o Bleaching and softening of core Clay 3.00°a 9° - <@ 91.02 GYVein 60.00° 2.00mm> <@ 91.05 GY VeIn 80.00° 30.00mm> aft 909 as 9fl as ,n I 0909 Sn 909 on 909 -.-—— 55U011414 4 nfl ci ,n In, 53U511415 a nn 9 ‘A ..- n nns 9 7A A Afl7 A A Al -I o4’)n o.,.,n 4 nfl a In flflQ4iAl7 CO 93.90 ° 4 flflDálAlQ A 96.90 96.90 CO A flflA ,,.,,,__ 010811419 A 0.00 96.90 97.90 n nn7 1.00 97.90 98.90 flflO44Afl 1.00 9890 9990 102 99_go 1_no 10090 114 0.007 1_no 99_go l0O90 1_no 119 0.007 10090 101_go 100 120 0.008 <1 <0_flos 131 n_one 2008/11104 Equity Exploration Consultants Ltd. °graphic log not to scale Page 4of12 Project: Taseko Hole Number: O8TSK-05 From To Rock-type & Description o From To Width Sample Cu Mo Au .— — — i 30 4 i40 50 0 4 0 4102.60 115.20_Andesite I Dark purple coherent andesite. Core competency is poor to moderate. Andesite is FP-phyrlc (25%) wIth a dark maroon, aphanitic matrix. All phenocrysts are altered to CL. Chlorite Is ubiquitous as fracture-coatings, phenocrysts, and veinlets. Fracture-coating PYthroughout interval, with hematite-staining. — Rare GY fractures. o Pervasive & fracture-coating Chlorite 3.00°eo 103.04- 104.18 Pod and surficial Hematite 0.20%oo 102.60- 106.10 Fracture-coating! disseminated Pyrite 0.20%oso 106.10- 109.20 Surficlal coating Pyrite 0.50%oo 109.20- 115.20 On fractures Pyrite 0.10%o 11o_ <@112.00 CL-HE Vein 2.00° 3.00mm> <@111.18 CL-PY Fracture 50.000> <@111.28 CL-HE-PY Fracture 60.00°> <@111.55 CL-GY-PY Fracture 70.00°> <@112.09 CL Fracture 65.00°> 1 101.90 102.90 1.00 00811427 107 1 0.006 2Q W80 tQ Q8ii42L 12Z t QL W80 W6J 20 Q8fl42L 12L i_ QQ6 6i t09J i43Q 1Q8 1_ 0QL i5.j 110.fO LQ0_ 00811431 114_ t_ Q.005 110.10 112.10 20Q_ 00811432 114_ 3__ 0.00L 11210 115.10 210_ G0811433 IOL_ L__ QIOL 115.20 121.50_Andesite_ Light grey altered andesite. Core competency Is veiy poor; all core is Intensely fractured creating very fissile rock materiaL Same protolith as before - rare relict FP phenocrysts. CL alteration most evident on fractures. PY on fractures and finely disseminated. MS-CY alteration bleaches the rock and causes a loss in igneous texture. o Disseminated Pyrite 0.30%oo Alteration of FP phenocrysts Sericite 3.00*00 120_ Clay 2.00°oo Albite 0.10%o 121.50 124.40_Volcanic - undifferentiated I Light grey incredibly crumbly (core coherence is very poor). Relict igneous textures of FP phenocrysts - altered to MS.CY. Trace to minor PY disseminated throughout (cubic crystal forms). ° Alteration of FP phenocrysts Clay 3.00°o a Alteration of FP Sericite 3.00*00 Pyrite 0.75%o 118.10 115.10 1.ona.0*. fl00.0 99 <1 0.006 12030 122.50 2.20 ,,ne,.,, 104 63 0.02 0.008 I 124.40 139.50_Andesite I Core is rubbly, locally competency increases. Andesite is generally porphyhtid5 In texture, with FP- and HB-phyric zones. HB-phyrlc andesite with CL alteration l1Ofl l&Afl )5fl I 2flOllA7 IRS I 0 flflC - - -- .. SI 2008111104 Equity Exploration Consultants Ltd. *graphic log not to scale Page 5 of 12 124.40 12L4 30D_ 00811438 112__ 1__ Q.OQL 127.40 13010. 21L 00811439 80._ 1___ 0105_ 130.00 131.50 1.50 0.006 LJ Project: Taseko Hole Number: O8TSK-05 Cu Mo AuFrom To Rock-type & Description From To Width Sample — — — St 30 4 0! 1’41 On l’0’, On ‘,flfl flflRl 1554 7, ei n fine IF 133.60 133.15 6QQ_ G0811442 75___ 6___ Q.QOL (pervasive and on fractures) from 120.0- 129.60 m and 131.0 - 133.0 m. Above and below this is the typical maroon FP-phyric andesite. Flow contacts are generally sharp. PY is rare - on fractures. a 124.40- 139.60 Chlorite 2.00°aa 127.50- 128.50 Competency decreases Clay 2.00°aa 133.30- 139.50 Competency is greatly reduced Fault Zone 0°aa 126.15- 128.45 Fracture-coating Pyrite 0.60%a 135_ <@132.75 GY Fracture 65.00°> <@132.82 GY Fracture 80.000> 139.50 152.95_Andesite I 140_ Dark purple-greenish coherent andesite, core competency is poor. FP-phyric andesite (25-40% squat- subrounded phenocrysts) in a maroon flne-gralned matrix. Trace pyrite. Rock is intensely fractured - most fracture planes are coated with HE-CL-GY. 145.. a Pervasive Chlorite 3.00*so a concentrated on fracture surfaces Hematite 0.10%,oa 142.60- 145.45 trace on fractures Pyrite 0.10%a <@147.90 CL-HE Fracture 55.00°> <@149.50 GY-CL Fracture 40.00°> <@152.56 HE-GY-CL Fracture 25.00°> 152.95 1 58.20_Andesite I Dark purple medium-grained andesite. Core competency is poor-angular clasts fill interval. HE-staining on most fractures. GY veining (white, soft, does not fizz with acid) is the dominant vein4ype. Cross-cuffing veinlets, average a few mm thick. Some surfaces have slickensides - some fault movement? 155_ <<pervasive and on fractures Chlorite 3.00°a <@153.47 GY-CL (irregular) Vein 35.00°> <@153.80 CY-CL Fracture 45.00°> <@156.90 GYVein 10.000> <@157.70 HE Fracture 38.00°> 15820 181.25_Volcanic - undifferentiated I Dark maroon with a greenish hue (CL alteration). Core competency Is generally poor. Fine-grained andesite(?). Moderate to Intense QZ-FP veining. QZ veiniJ.. 2008111104 Equity Exploration Consultants Ltd. jq an iai no I an isi nn is, an i en -._.=_=— 020611445 isi nn is, an i en 40 —.— 02061i444 , is, an isa fin i an 47 n ni , ,aAfln iagnn ,nn n fine - 020611440 iACflfl lA7flfl inn is, flflfluIAA7 a, IC, n fine 7, 148.50 150.00 1.50 —4 150.00 151.60 1.50 -n fine G0811450 139 G081 1461 <1 120 <0.005 <1 <0.006 isian iann ian 1a<nn iaan Ian iasan laann ian St tInSi iaao <1 taann 15700 ian as 1R7 an L2Uo11q44 <finns <1 a, <n nna 020811440 <1 75 04.0.45 !&LtL_ 0,0011000 <n nna Si Nt 0<7 <n nna Si <n <ma 158.20 159.70 L5Q_ G0811457 51___ 1__...... <.6Q5 158.70 15i2 t62 Q5L 33 <1 <0006 161.20 164.00 2.80 G0811459 40 <1 <0.005 *graphic log not to scale Page Got 12 Project: Taseko Hole Number: O8TSK-05 From To Rock-type & Description j (14 mm) with CL-HE alteration. Chaotic veining makes interval crumbly, where core fractures along veining. CL alteration on fractures. ii Chaotic with CL selvages Quartz Veining 2.00* so 175.80- 180.30 Angular & 165.. rubbly Fault Zone o <@160.32 QZ-FP (CL selvage) Vein 30.00*4.00mm> <@167.50 CL Fracture 70.00*> <@167.70 QZ-CL-HE Vein 10.00* 5.00mm> 170_ <@180.00 QZ Vein 80.00*3.00mm> 776.. 18o I8j2L_j84.50Volcanic - undifferentiated I Dark purple medium-grained volcanoclastic andesite? Increased core competenc Veining becomes more prominent (CA-QZ stockwork veining) core looks like crackle breccia texture. Veins have CL alteration (green hue to many of the veins). Some veins are very soft - suggesting some GY-AH. No mineralization observed In veining. The dominant vein orientation is parallel to core axis. <@181.35 CA.QZ-CL veining, minor Gypsum Vein 25.00° 8.00mm> <@181.75 CA-QZ-GY-Cl. Vein 50.00° 5.00mm <@184.35 QZ Vein 3.00*> 184.50 212.80_Volcaniclastic I Light purple-green, medium-gralned volcaniclastic (igneous texture hard to 185.. identify). FP phenocrysts - altered to CL, proximal to veining. Veinlets throughout, typically at 65-90 to core axIs. Sub-angular to sub-rounded clasts (andesite In composition?). Veining at contacts between flow units. Composite CA-GY-HE veIning, often Irregular and range In width. Abundant blebs of HE, in veining and dIsseminated. At 202.9 m QZ-PY (at margins) vein is cross-cut by 198..later CA-GY veining. 0 40 4 0 4 2008111104 Equity Exploration Consultants Ltd. °graphic log not to scale Page 7of12 Project: Taseko From To Rock-type & Description a Calcite Veining 2.50*sse 194.40-194.45 Clay-dominated Fault Gouge Zone 90.OOaa 202.45- 204.50 DissemInated, around QZ veins Pyrite 0.5%sa 184.50- 202.50 Disseminated & in veins Hematite 0.50%as 184.50- 212.00 Pervasive Chlorite 1.50°ea 207.60- 209.70 Finely diseminated Pyrite 0.10%a 195 <@185.00 CA-GY-HE Vein 40.00° 6.00mm> <@185.56 CA-GY-HE Vein 5.00° 20.00mm> <@186.90 GY-CA Vein 40.00° 3.00mm> <@187.23 GY-HE Vein 65.00° 30.00mm> <@190.45 CA Vein 35.00° 10.00mm> <@191.00 CA Vein 45.00° 2.00mm> <@191.80 CA-GY (minor CL at margins) Vein 85.00° 25.00mm> <@194.80 CA-GY Vein 20.00° 30.00mm> <@196.80 GY-CA Vein 35.00° 28.00mm> <@199.35 GY Fracture 40.00° 2.00mm> <@200.70 CA Vein 35.00-45.00° 1.00-5.00mm> <@202.90 QZ-PY Vein 30.00-15.00° 10.00mm> <@207.70 AC-CA Fracture 50.00°> <@209.40 CA-HE-CL Vein 35.00° 3.00mm> <@210.50 HE.CL-CA Fracture 30.00°> <@212.30 GY-CA-CL-HE Fracture 40.00°> <@212.60 CA-GY Vein 75.00-80.00° 25.00mm> <@214.60 CA Vein 85.00° 35.00mm> <@215.55 CA-CL Vein 25.00° 2.00mm> 212.80 218.80_Volcaniclastic I Similar to above - variation in colour and dominant igneous texture only. HB phenocrysts. Still voicaniclastic - likely andesite in composition. Decreased veining - moderately veined. Weak-moderate CL alteration. CA-GY-QZ composite veining, but CA dominates. HE on fractures and often associated with veining. Locally pinwred hue-HE staining? 215_ <@214.60 CA Vein 85.00° 35.00mm> <@215.55 CA-CL Vein 25.00° 2.00mm <@215.85 CA-GY Vein 50.00° 30.00mm> <@219.45 CA-GY (centre-fill) Vein 90.00° 45.00mm> <@220.36 CA-GY Vein 90.00° 25.00mm> <@220.00 CA-HE Vein 60.00° 3.00mm> 1 r Hole Number: O8TSK-05 2 5 4 5 4 5 4 0 4 0 4 0 4 From To Width Sample lasso 19550 ina° a Cu Mo ppm ppm Au ppm o so 202_ 205_ 210_ 100.5Q 107.50 iQQ_ G0811479 93__ 5___ <Q.QQ5 i57.sa 1050 I00 Q81i450 101 2 çQ.5fl5 10S.50 109.50 1.00_ G0811481 132_ t__ Q.Q0& 109.50 200.50 1.5Q_ G0811482 SL_ t__ Q.OQL 200.50 201.50 1.QQ_ G0811483 IQL_ t__ <iLQQS 201.5w 200.50 iQQ Q811A8L 99 t c0.005 201.5k 202.50 1.5Q Q8114SL 202.5 203.50 i00 Q81L 11L t cO.5Q5 2Q3.5 204.50 iQQ Q8415L 109 t c0.006 205 203.50 150 Q4014S 101 0L 2Q5.5 205.50 1.50 021i4S 77 t <006 2Q5 20L50 10000 63 t <006 2QL5 203.50 1.5Q 128 t <006 2Q9.5L 209.50 1.50_ G0811492 13L_ 2__ -Q.006 209.50 210.50 100_ (30811493 13L_ L_ cQ.oQS 210.5 21150 100 051J49L 405 <1 0.0Q5 211.59. 213.50 1.0Q_ (30811498 SL_ 4__ 9.005 213.50 214.50 100 212.50 213.50 1.00 95 5 <0.005 214.50 215.50 1.00 215.50 21650 tOO 72 21&50 21650 000 184 <0.005 <1 21650 21750 1_On 99 0.005 <1 2I7SO 2l9Sn 1aa 0.005 114 <1 so <a-ens <aans 2008111104 Equity Exploration Consultants Ltd. *graphic log not to scale Page Sot 12 2I$L246.50_Andesite I Dark green, medium-grained andesite, core competent. HB & FP phenocysts (t 20% HB, 15% FP) in fine-grained matrix. CA+i.QZ-GY veining (typically few mm wide up to 20 mm; —90 and 70 to core axis. HE on fractures - typically asociated with CA veining and fractures. a Fracture-coating & around vein margins Hematite 0.50%aa Calcite Veining 225 1.50°c s Alteration of HB Chlorite 1.50°cc 240.20- 245.50 Calcite Veining 2.50°c <@229.73 QZ-CA-GY Vein 65.00° 10.00-15.50mm> 230_ <@230.60 CA Vein 70.00° 20.00mm> <@243.60 CA-EP Vein 70.00-80.00° 2.00mm> <@244.50 GY-CA with sub-angular clasts of andesite Vein 50.00° 10.00mm> <@245.70 CA-CL Vein 20.00° 3.00mm> <@245.35 CA-GY-CL Vein 70.00° 4.00mm> 235_ Project: Taseko Hole Number: O8TSK-05 From To Rock-type & Description Cu Mo Auy From To Width Sample 0 4 0 4 ,lacn ,laen Inn .... tue1,5u3 0 ‘40 100 GQIQ 21Q ‘.2Q0 tO_ G0811505 a2Q.50 2i50 tQ0 Q24i 24 1 005 22L40 ‘.22.40 100 G0811507 70_ Q05 222.40 223.40 LQ0 GOBI 1508 63. j__ Q.0Q5 223.50224.50 t00 024i40 94 2 0Q5 224.50 23.Q0 3.50 040Ii 7 2 005 223.00 220.40 1.5Q_ G0811511 45 4_ Qg5 220.50 231.40 230_ G0811512 toL_ t__ Q.Q08 231.50233.30 UQ O0311iI 2 i 233.30 224.20 IAO_ (24811514 IOL_ __ 0.0Q5 234.70 236.40 tZQ_ G0811515 120 3. 236A0 ULOQ t5Q 0311I 4 Q08 237.00 ‘.30.40 1.50 (24811517 ISL 3. 230.40 240.0 L50_ GOShISIS t31 <L 0.305 240.00242.40 t60 Q81L 91 1 05 242.40 243.40 t50_ G0811520 10.L 2 Q.QQ 343.90 ‘44A0 0.50 G0311$21 8 1 95 344.40 ‘Ai90 L5Q 031i52L L 0.005 245.90 246.30 340 (24811523 133. 4 Q.090 0 3 0 4 0 4 0 4 0 4 4 1. 2Aft fl 9A0 AG 240_ 245_ Dark green, medium-grained andesite. Core competent. Localized flows of HB-phyric andesite (FP phenocrysts in a fine-gralned igneous matrix). CA-GY veining (typically few mm, up to 40 mm; often 80-90 to core axis and 0-10). CA veins with GY centres are common. Rare CL alteration associated with veining. <sCalcite Veining 3.00° cc Chlorite 1.50°c .< @247.00 CA Vein 60.00° 3.00mm> 246.40 247.90 246.40 247.90 1.60 G0811524 110 1 <0.005 1.50 247.90 249.40 G0811525 1.50 G0811526 91 1 <0.005 2008111104 Equity Exploration Consultants Ltd. °graphic log notto scale Page 9of12 <@248.86 CA (-1 m, salmon pink?) Vein 12.00° 4.00mm> <@250.70 CA-GY-AH (salmon pink) Vein 70.00° 2.00mm> <@251.00 PY Fracture 10.00°> <@252.20 GY-CA Vein 15.00° 15.00mm> <@252.70 GY-CA Vein 30.00° 25.00mm> Project: Taseko Hole Number: O8TSK-05 From To Rock-type & Description From To Width Sample Cu Mo Au? — — — E!L. 249.00 259.20 Volcanicbstic Purple-dark grey, medium- to coarse-grained volcaniclastic. Core competent Locally porphyritic and HB-rich (30%). Sub-rounded clasts of feldspar.phyric andesite. Weakly developed CA veining (typically few mm). No mineralization observed. a Chlorite 1.50°ooi 249.30- 250.90 Calcite Veining 1.00°ae 250.90- 252.10 Intense, thin, anastomising Calcite Veining 3.50*5 255_ <@256.50 CA-HE Fracture 75.00°> <@257.80 CA Fracture 50.00°> 0! 259.20 298.10 Andosite 249.40 250.90 t50_ 00811527 91___ 1___ <0.Q06 260.90257.40 ti Q6I1528 °,2 252.40 253.90 t50__ 00811529 4t t__ c0.005 ‘302 On ‘300 An I Cfl 256.90 258.40 1.50 I (i0311530256.40 256.90 t5Q_ 00811531 85 f_ Q,ggL 74 <1 <0.005 0 3 0 4 0 4 0 4 3 4 0 4 \t° Dark grey.green porphyritic andesite. Core competent Phenocryst population 260_(—10 up to 35%) dominated by squat HB phenocrysts, locally CL-altered. Also FP phenocrysts are altered to CL-MS. Irregular CA veins with diffuse margins (typically less than 5 mm wide, unmineralized, 55-70 to core axis). Moderate pervasive CL alteration, with CL-EP selvages. Thin microveinlets with alteration haloes of ms(?). Trace HE - particularly along fracture planes. MS alteration around cluster of CA veins at 279.6 m. 276.2 and 278.6 m: FSPO, gradational contact, medium-grained and locally up to 20-30% phenocrysts. 281.9-282.8 m: VCLC. Dark maroon volcaniclastic with sub-rounded clasts p265 — andesite of varying Composition and phenocryst content Vary from FP-phyric (up to 3 mm, squat) to phenocryst-poor, almost aphanitic andesite. FP phenocrysts exhibit flowtextures, flowing around clasts. Chaotic igneous texture. MS alteration at both the upper and lower contact with the dark green andesite. 282.8-298.1 m: Pervasive alteration surrounding a 8 cm wide, massive QZ-CA vein with fragments of host rock and a dark mineral disseminated (tetrahedrite?), that is typically associated with PY. 256.40 259.90 t5Q_ 00811533 83. SI <0.006 259.90 261.40 t5L 00811534 103_ t__ <.0.006 251.40 252.90 LS0_ G0811535 IIL_ Si_ <.0406 262.90 254.40 1.50_ G0811536 12L_ £L_ 0.005 254.40255.90 t40 L 116. <1 %0Q5 266.90 257.40 L50_ 00811538 1iI L_ 0.00S 257.40 256.90 t50_ 00811539 79. cQ.0QS 257.40 265.90 l4tL_ 00811640 255.90 270.40 t50_ G0811541 82. L_ 0.005 70.40 271.00 1.00 40SI1ML 93 Q.0QL 271.00 273.40 1.60 00311543 109. j <0.006 273.40274.90 L60 051i644 64L 2 c9.0Q5 2_13.40 274.90 1.6Q 00811545 274.90 276.40 L6Q_ 00311546 137 L_ <0.0Q5 276.40 277.90 1.SQ_ 00811547 94 L_ <0.005 271.90 279.40 1.6Q 00811545 141 <1___ cQ.006 279.40 280.90 1.5Q_ 00311549 77 j__ <_0.0QS 250.90 26.1.90 1.00 00811550 IOL <1____ <Q.005 281.90 ‘.47.80 0.90 0511551 57 <1 c0.005 262.90 ‘.64.80 L6L 00811552 18L L_ cO.005 284.90 ‘.65.80 1.6Q_ 00811553 15L 2__ 0’l.02L 2008111104 Equity Exploration Consultants Ltd. *graphic log notto scale Page 270_ <<Alteration of HB & in veins Chlorite 2.50°s a 259.20- 269.80 Epldote 1.50°a <<269.80-291.60 Hematite 0.30%aa 269.80- 274.00 Serlcite 1.50°c a 281 .90-282.80 Pervasive -vein related? Sericite 2.00*5 a 259.20- 260.00 In veins & on fractures Pyrite 0.20%s a 285.2- 286.20 Pyrlte 3.00%aa 259.2- 279.60 Calcite Veining 1.50<ca 279.60- 281.30 Calcite Veining 3.50*55 281.30- 291.60 Calcite Veining 1.50*sa Chaotic Calcite Veining 35Q* <@259.50 CA-PY Vein 30.00° 10.00mm> <@262.10 CA-EP (at margins) Vein 40.00° 4.00mm> <@262.40 QZ-CA-EP (EP at margins) Vein 80.00° 24.00mm> <@263.40 CA-CL-GY Vein 40.00° 2.00mm> <i@264.00 QZ-CA Vein 40.00° 1.00mm> <@264.35 CA (EP selvage 25mm) Vein 55.00° 8.00mm> <@265.20 CL-CA composite Vein 4.00° 40.00mm> <@265.50 CA-CL Vein 30.00° 1.00mm> <@265.50 CA-GY (salmon pink) Vein 50.00° 4.00mm> <@267.30 CA-FP-CL (crustiform) Vein 30.00° 20.00mm> <@267.90 CA-CL Fracture 45.00°> <@269.30 CA-GY Vein 8.00° 3.00mm> <@270.90 CA-CL Vein 250.00°> <@271.30 CA-GY-CL-EP Vein 20.00° 3.00mm> <c271.70 CA-CL (at margins) Vein 55.00° 4.00mm> <@272.70 CA (massive crystalline) Vein 20.00° 5.00mm> <@272.80 CA-CL-GY Vein 25.00° 5.00mm> <@273.25 CA-DOL vein Vein 75.00° 20.00mm> <@273.80 CA Vein 70.00° 3.00mm> <@274.50 CA-CL Vein 25.00-55.00° 3.00mm> <@274.90 CL Fracture 45.00°> <@275.65 CA-CL Vein 65.00° 5.00mm> <@275.90 CA (CL selvages) Vein 50.00° 7.00mm> <@277.10 CA-HE Fracture 30.00°> <@277.30 CA-GY Vein 60.00<2.00mm> <@278.50 GY-CA (continuous for 30 cm) Vein 10.00<2.00mm> <@279.20 CA Vein 70.00° 20.00mm> <@279.50 CA (MS selvage 30 mm) Vein 70.00° 3.00mm> <@281.90 HB-phyric ands & vclc Contact 50.00°> <@282.50 CA-QZ Vein 60.00<4.00mm> Project: Taseko Hole Number: O8TSK-05 From To Rock-type & Description / From To Width Sample o°pm p°m pi 0 40 40 40 40 4 285.80 287.30 1.50 111 2 0.031 28Z30 255<SP 14Q_ G0811555 4L st 2SS,8G SQ 1.S G0811556 94_ —_--- 25030 29t80 tSQ G0811557 112 t__ 0.0lI5 2SI.G LSQ_ G0811558 1i8__ 1____ Q.QQS_ 283.30 284.80 L80 G0811559 14L L_ 0.005 254.80 286.30 t5 (28811580 04. t__ Q.QIL 8 50 4 \° \ \ 27< — 280_ 0<5 290_ IE_ 00 2008111104 Equity Exploration Consultants Ltd. *graphic log notto scale Page 11 of 12 <i 282.70 HE Fracture 50.00°> <@286.80 QZ.CA-PY (+ darkgrey mineral) Vein 30.00° 80.00mm> <@286.90 CA-QZ (composite) Vein 60.00° 25.00mm> <@287.50 CA 55.00° 2.00mm> <@289.10 QZ-CA (CL selvage) Vein 55.00° 2.00.8.00mm> <@289.60 QZ-HE Fracture 25.00°> <@290.40 CA.CY Vein 20.00° 2.00mm> <@292.50 AH-CL Vein 45.00° 15.00mm> <@293.50 QZ-M5 Vein 80.00° 35.00mm> <@293.70 CL-HE Fracture 65.00°> <@294.70 CA 35.00° 4.00mm> <@295.50 QZ.CA-MS Vein 35.00° 20.00mm> <@296.20 GY-CA Vein 50.00° 40.00mm> 29L10_.310.30_Volcaniclastic I Dark green with areas of maroon voicaniciastic andesite. Sub-rounded clasts of maroon andesite which become larger with depth. Sharp clast boundaries, so3- with veins exploiting the contact. VaryIng phenocryst content. CL-MS alteration locally obscures original igneous texture. Decreased veining intensity. Vein thickness average several mm only. • 298.10- 310.30 Calcite Veining 1.00°.. Alteration of FP phenocrysts Sericite305 - 1.00°. <@300.90 QZ-CA (with andesite clasts) Vein 50.00° 5.00mm> <@301.20 GY-CA-CL Vein 15.00° 2.00-5.00mm> <@303.60 02-CA (CL selvages) Vein 40.00° 5.00mm> 298.40 299.90 1.50 jQ_31O.3O_EOH___________________________________ Project: Taseko Hole Number: O8TSK-05 From To Rock-type & Description From To VAdth Sample pm p0m p 50 0 400 40 40 40 40 4 0 4 290_ \ 0 • ,‘ 255..30 250..40 2JQ 00811561 t55 <j Q0j G0811562 94 <1 0.006 259.00 3O1AQ .tSQ_ 00811563 W2 ‘c1._ Q..QQL 0i.40 302.OQ j.5Q__ 00811654 9S___ ci____ ooos 01.4P 02.00 1SQ__ 00811565 04.4Q t00_ 00811566 144_ j .005 04.4 30590 tSQ_. G0811567 95____ 1____ 0005_ 05.50 30L4Q t5Q__ 00811558 52 <1____ 0.0Q5 7.4Q 0000 t50_ 00811569 tlL_ 1_.. Q.0PS Q8.9 3iQ3Q t40_ 00811570 12L.. L Q.000 2008111104 Equity Exploration Consultants Ltd. *graphiclognottoscale — — — Pel2ofl2 ,A, • EQUITY I EXPLORATIONI CONSULTANTS LTD. Project: Taseko Collar elevation: 1592.Om Hole: O8TSK-06 Azimuth: 320.00 Proposed: O8TSK-D Dip: -65.0° Location: 453337 m East 5668764 m North Length: 304.80 m Prospect: Hub Date started: Date completed: 2008/08/23 2008/08/28 Claim: 354057 Objective: Logged by. L.Hollis O8TSK-06 was collared 150 m to the southeast of drill hole O8TSK-03, in the mag low. Drilled by: No Limit Assayed by: ALS Chemex Core size: HO/NO Dip tests by: Reflex MS SUMMARY LOG: 0.0 — 9.3 m: CASING. 9.3 - 77.Om: DIORITE. MG-Bl-altered. QZ-veins. Localized MS. CP:0.3-3%,PY:0.3-3%, MO: 0.01% 77.0 - 86.5m: BRECCIA - Intrusive (?). MG-Bl-altered. QZ veins. CP:1.5-2%, PY-1.5%, MO: 0.01-0.03%. 86.5 - 91.Om: GRANODIORITE. CL-SI-altered. CP: 0.3%, PY-0.5%, MO:0.01%. 91.0 - 159.lm: BRECCIA - Intrusive (?). MG-BI-altered. QZ veins. CP:0.1%, PY:0.1-0.3%. 159.1 - 161.Om: ANDESITE. MG-aLtered. QZ-GY veins. Localized MS-SI-alteration. 161.0-256.5m: ANDESITE. MG-altered. QZveins. CP: 0.1-1%, PY: 0.3-1%, MO: 0.01-0.03%. 256.5- 269.8m: DIORITE. MG-altered. QZ veins. PY: 0.5-1%, MO: 0.03%. 269.8- 274.lm: FELDSPAR PORPHYRY. MS-CL-altered. PY:3-4%. 274.1 -278.4m: DIORITE. MG-altered. QZveins. PY:0.5-1%, CP:0.3%, MO:0.01%. 278.4-304.8m: ANDESITE. MG-CL-altered. QZveins. PY: 0.3-0.5%, CP: 0.05-0.1%. 304.8 m: EOH 200 , a4 ,I 4 - 01 () r’, ) C O - (11 . C’ ) 2. m CD 0) C 0 ) 1% ) 01 - - J () CD 01 C Q C -< C ) 0) 01 (31 (51 01 01 01 . - . 01 - . n m 0 0 0 0 0 C 0 0 0 0 0 o x 3 ( ) > N P 01 L ) C ) . 11 . C’ ) C’ ) - C’ ) - C C o o C C C C C C 0 0 C z . I I I 0 C) I 0 o 05 C)) 0 — I Co o - I n 0) c o rn 0 0 ) Project: Taseko Hole Number: O8TSK-06 From To Rock-type & Description 0.00 9.30_Casing I Poor recovery milled pieces of core 9.30 17.00_Dlorlte I Dark grey, porphyritic diorite; same rock as seen in previous holes at the Hub (O8TSK-01, -02, -03, and -04). Core competency is moderate. PF phenocrysts (up to 25%), typically 5 mm long. Pervasive MG-Bl+I-Sl alteratIon of matrix and Mi6 - alteration of BI and HB phenocrysts. Locally, alteratIon makes the rock appear less porphyritic. Weak QZ-CP-PY (trace BO) veining, typically 10 mm wide, ,7 — locally with MO. Localized MS-CL.PY alteration as vein selvages. Fracture-coating CP-PY.MG.MO. /17.5/; a Pervasive throughout matrix Biotite 2.50*5 a Pervasive throughout matrix ,,1 Msgnetite 2.50°sa 13.80- 15.00 VeIn-related Sericite 3.50°aa 9.30. 13.80 Alteration of Bl, HB, & matrix Chlorite 2.50°c a 13.80- 15.00 Pervasive, matrix Chlorite 3.50*ca 15.00- 17.00 Chlorite 2.50*55 9.30- 13.80 Pyrite 1.50%sa 13.80- 15.00 Pyrite 3.00%aa 15.00- 17.00 Pynte 1.50-2.00%a a /7.S 9.30- 17.00 Vein-related Chalcopyrite 1.50%e a At margins of QZ veins Molybdenite 0.10%s @ 9.38 PY-MG Fracture 42.00°> <@ 9.63 QZ-CP Vein 70.00° 5.00mm> <@ 9.70 Qz-cP-MG Vein 65.00° 1.50mm> <@ 10.80 QZ-(trace PY) Vein 55.00° 3.00mm> <@ 11.20 QZ-CP Vein 40.00° 18.00mm> <@ 11.90 QZ-CP-MO (at margins) Vein 70.00° 9.00mm> <@ 11.99 QZ-CP (trace in centre) Vein 60.00° 15.00mm> <@ 1245 QZ-PY-CP Vein 60.00° 2.00mm> 15 <@ 12.45 PY Vein 65.00° 1.00mm> - <@ 12.65 QZ-MU-PY Vein 40.00° 3.00mm> <@ 13.00 CP Fracture 30.00° 1.00mm> <@ 14.00 QZ-PY-(trace MO) Vein 70.00° 36.00mm> <@ 14.30 QZ-PY (trace MO) Vein 68.00° 45.00mm> 2008111103 Equity Exploration Consultants Ltd. *graphic log not to scale Page 1 ofl3 <@ 16.30 QZ Vein 35.00° 3.00mm> @ 16.80 QZ-CP-MO Vein 50.00° 2.00mm> 17.00 32.50_Diorite__________ Porphyritic diorite, same as above. Good core competency. Oscillatory-zoned FP phenocrysts (25%) typically —5 mm in size, up to 10 mm. Alteration gives the phenocrysts fuzzy edges. Patchy BI-MG alteration. MS strongly developed as large selvages to QZ veins. Moderate, pervasive CL alteration. PY-CP..trace MO on fractures and as veinlets. Sub.rounded clast of CL-altered, equigranular quartz monzonite (81-MG alteration absent). ° Patchy Biotite 2.50°s a Patches & blebs on fractures Magnetite 2.00°sa Around veins Chlorite 2.50*5 a Vein-associated Serlcite 1.50*55 17.00- 24.05 Pyrite 2.00%aa 24.05- 27.00 Pyrlte 1.50%sa 17.00- 20.05 Chalcopyrite 1.50%aa 20.05- 24.05 Chalcopyrite 0.30%,>a 24.05- 27.00 Chalcopyrite 0.50%aa 20 — 17.00- 25.00 Molybdenite 0.10%s a Molybdenite 0.20%aa Pervasively replaces matrix Magnetite 2.50°sa Biotite 2.50°s a Replaces BI Chlorite 3.00°a a Locally replaces FPI in selvages Sericite 2.50*55 Pyrite 1.50%ee Molybdenite 0.20%a a 27.00- 30.80 Chalcopynte 0.75%a a 30.80- 32.50 Chalcopyrite 1.00%a </ 17.28 MO-PY Fracture 60.00°> <i 17.38 QZ-PY-CP Vein 40.00° 9.00mm> <@ 17.60 PY-PO Fracture 30.00°> < 17.90 MS-PY Fracture 65.00°> <@ 18.80 QZ-CP-PY Vein 12.00° 1.00mm> <t 19.10 QZ-FP-CP Vein 60.00° 8.00mm> <@ 19.10 PY.QZ Vein 60.00° 1.00mm> <@ 19.25 CP-PY Fracture > <@ 19.40 QZ-MU Vein 75.00° 2.00mm> <@ 1950 QZ-MS-PY Vein 45.00° 2.00mm> </ 20.15 QZ-PY-CP Vein 50.00° 2.00mm> <t 20.35 QZ-CP-MO Vein 60.00° 10.00mm> </ 21.40 QZ-CP Fracture 40.00°> <@ 22.90 QZ-CP (in centre) Vein 70.00° 8.00mm> <c 23.60 QZ-FP-PY Vein 60.00° 6.00mm> <c 24.00 MO Fracture 66.00°> < 24.05 MO Vein 50.00° 4.00mm> <I 24.20 PY-CP Fracture 15.00°> Project: Taseko Hole Number: O8TSK-06 > CuMo AuIonFrom To Rock-type & Descript From To Width Sample 050 5 40 05 3 0 0. 0 5 0 4 “4 I, II I, ‘4 7 /7 ‘4- ‘4 /74 // “4 // ‘7% /\j 7% /7% “4‘ I, //44 /.,%44 // ‘4- ‘7— “404 “7%- “4, ILSQ_ 1J.30_ 40_ G0811578 1ii 32_ %Z3L 1L3Q 18Q 100 ZL 8ZL 21 %OSL 18.30 IL3Q_ .Q0 G0811580 1.&30 19.3L I0Q_ G0811581 755_ 24_ %SIL 19.3Q 21L3L IOL G0811582 1ll7Q_ 43_ O.OIL 20.30 2j.3Q_ iSL G0811583 73L_ St_ ‘iL 213Q 22.30_ jOQ_ G0811554 ZZL_ IL_ %21Z ‘1.3Q 22.3Q_ tOO— G0811585 22.3Q 23.30_ iQL G0811586 1520_ 5L_ ‘I.Q3L L tOO- 08i1SL 4O- 3L 44 24.3Q 26.3L jQO- G0811588 1310_ 52_ Q.OZL 25.30 26.30 iOQ_ G0811589 1340_ 255_ %04L 26.30 aZ.3L tOO- G0811590 692_ 202__ Q.OL ZL3 28L tQ0 O89t Z94 43 0IL 28.30 29 tOO- 089 6Th 5L 02L 29.30 3Q.3L tOO- G0811593 124Q_ 62__ Q.OO4 30.3Q 3tL jOQ_ G0811594 1O25_ 2O5_ 01019 31.30 32L tOO- 081i9L 889 36 Q2 25 — 2008111/03 Equity Exploration Consultants Ltd. ‘graphic log not to scale Page 2 of 13 @ 24.50 QZ-PY Vein 12.00° 5.00mm> <c 25.10 PY-CP-MG Fracture 60.00°> @ 25.70 MO-PY-CP Vein 75.00° 5.00mm> @ 25.80 QZ-PY Vein 60.00° 6.00mm> <@ 26.40 QZ-PY-CP Vein 15.00° 12.00mm> <@ 26.30 QZ-MO (margins) Vein 66.00° 10.00mm> <( 27.20 CP-MO-BO Fracture 75.00°> <@ 27.65 QZ-PY(Minor) Vein 60.00° 2.00mm> <@ 27.90 MG-CP Fracture 80.00°> <@ 28.05 QZ-PY (MS selvage) Vein 60.00° 3.00mm> <@ 28.30 QZ-PY-CP Vein 65.00° 2.00mm> <@ 29.30 QZ-PY-CP Vein 50.00° 1.00mm> <> 29.75 QZ-PY (trace) Vein 40.00° 4.00mm> <@ 30.62 QZ-PY-MO (Mo at margins) Vein 65.00° 9.00mm> <1 30.90 QZ-CP-PY Vein 80.00°> <l 31.60 QZ-PY Vein 40.00° 8.00mm> <@ 32.30 QZ-PY Vein 60.00° 2.00mm> <i 33.20 MS-QZ-PY Fracture 50.00°> Light grey diorite, good core competency. Fine-grained mottled appearance - lose good porphyrltc texture, however locally large FP phenocrysts. Increase in KF alteration? QZ veining, with MS-CL selvages. Increase in disseminated and interstitial CP.PY. Gradational contact between intrusions? Small clasts of <@ 33.10 QZ-MS-PY Fracture 50.00°> <i 33.40 QZ Vein 80.00° 5.00mm> <@ 33.60 CP-PY Fracture 70.00°> <@ 34.05 QZ (CL-MS selvage) Vein 45.00° 5.00mm> Project: Taseko From To Rock-type & Hole Number: O8TSK-06 a On fractures, in veins & disseminated Pyrite 2.00%>, a Disseminated & in fractures Chalcopyrite 1.50%a Dark grey to black porpyntic diorite. Moderate to good core competency. Texture locally obscured by alteration; matrix beomes fine-grained and dark grey with large, relict FP phenocrysts, often with fuzzy boundaries. Pervasive I and CL alteration. . .... Equity Exploration Consultants Ltd. °graphic log not to scale Project: Taseko From To Rock-type & Description selvages. PY, CP, and MO also as fracture coatings. Thin 02 veinlets often contain flakes of MO. Intense MS-CL indicative of phyUic alteration. Disseminated PY and CP from 60 m. 46.3-51.2 m: Milky 02 veins cut by QZ-PY-MO veins (all with CL-MS selvages). 54.3-57.3 m: Interstial CP, PY, and MO. QZ-PY-CP stringers (<1=1 mm) cross-cut 40 — core intensely, some have MS selvages. Sub-angular clast of altered andesite at —56 m (strongly magnetic, fine-grained, contains truncated 02 vein). 60.4-66.5 m: Sub-rounded clasts of CL-altered granodiorite, up to 13 cm in length. Could be dykes although no chilled margins observed. 02 veining throughout diorite but not granodiorite. <Obscures igneous texture Magnetite 2.50°sa Local Biotite 2.50°s a Pervasively replaces HB & SI Chlorite 2.50*5< Proximal to veining Sericite 2.50°se Quartz Veining 3.00’sa 35.40- 57.30 Pyrite 1.50%aa 35.40- 38.30 Chalcopyrite 0.30%aamo 0.10%aa 38.30- 42.40 Chalcopyrite 0.50%soemo 0.30%sa 42.40- 49.00 Chalcopyrite 0.75%sse 42.40- 54.30 Molybdenite 0.10%aa 49.00- 54.30 40 — Chalcopyrite 1.25%aa 54.30- 57.30 Chalcopy rite 0.75%aa Molybdenite 1.00%a a 57.30- 66.50 Pyrite 1.00%a <57.30- 71.50 Chalcopyrite 0.30%sa 57.30- 77.00 Molybdenite 0.10%ae 66.50- 71.50 Pynte 0.50%s a 71.50- 77.50 Pyrite 0.50%se Chalcopyrite 2.00%s <@ 35.45 QZ-CP (MS-CL selvage) Vein 50.00° 6.00mm> <@36.40 QZ-PY Vein 80.00° 7.00mm> <@ 36.60 QZ-MO-CP Vein 60.00° 5.00mm> <@37.10 CP-QZ Vein 35.00° 2.00mm> <@ 37.20 MU-QZ.CP-PY-MG Fracture 35.00°> <c 37.30 QZ-CP-MO Vein 65.00°’ <@37.50 QZ-MU.CP Vein 30.00° 5.00mm> <@ 38.40 QZ-PY-CP-MO Vein 70.00° 15.00mm> <@ 38.70 EP Fracture 30.00°> <@ 40.67 QZ-PY-CP Vein 70.00° 4.00mm> <@ 42.96 QZ-CP-PY-MO Vein 40.00° 4.00mm> <c 46.80 QZ-GL-MO-CP-PY Vein 50.00° 4.00mm> <@ 48.10 QZ-KF Vein 80.00° 3.00mm> <@ 48.16 MU-CP-PY Fracture 85.00°> <@ 49.80 QZ-PY-CP-MG Vein 70.00° 3.00mm> <@ 51.40 QZ-PY-CP Vein 50.00° 5.00mm> <@ 51.60 PY-MS Fracture 75.00°> K 0 5 Hole Number: O8TSK-06 0 40 40 4 0 5 From To Width 0 4 40.30 41.30 tOO S I Cu Moamp e ppm ppm ppm it’ I— I— I— I, II II I— ‘ // <‘ I,— , // so_ 4t30_ 42.30_ t0_ G0811606 1150_ 1ø Q.008 42 43.3Q L00 048I80L 534 65 Q1 433Q_ 44.30 tQ0_ 00811608 485_ WL P&1± 44 4 1QQ 05fl60 1680 39Z Q1L 45.30_ 46.3L 1&P_ 00811610 USL 312__ Q.212 45.30_ 4l.Q_ i.PP_ 00811611 298L 13L Q.1L 473L 48.3Q 1QP 00811612 1SQQ_ 1 Q.072 48.3L 49L tQQ_ 00811613 260L 1Q QJSL 49.30_ 50.3L LOQ_ 00811614 1515_ I SO.3L. 51.30 tOQ_ 00811615 629_ L_ Q.02L Si3L S2.3L jQ_ 00811616 82L 184 Q.0Ii S2 530 IQQ 0811 1205 123 0.013 54.3Q tOQ 08IIS1L 959 98 54.3Q_ 55.Q_ j9_ 00811619 15i0 64. Q,042 5SQ 55.30 0Q P8iiS20 5.Q_ 55jg jQ 00811621 189L 1fi__ 0.0Th 86i0_ 173L 1.QQ_ G0811622 U85_ 136_ m 73p c&3g jgg 00811623 150L S4 0.0W 8.3Q 59.3p jQ_ 00811624 1000 69 07 8.3Q_ 59.3L 1.00. 00811625 89.30_ 60.30 j.0P_ 00811626 1305_ -34_ 9.0W 80.30_ 1.30 tQO_ 00811627 1I70_ 3s 4t3L 62.3L L00_ 00811628 955_ ZL_ QJII2. 5Z30 6130 L00 08ii82L 1125 348 0.0II 83.3O 540 t00 08ii8Th 1S 8 9.0W 54.3L. S5.30_ t 00811631 841_ Th__ ‘I.008 8S.3L S6.30_ L01L 00811632 jj55_ j 9.0j3 86Q L3Q 100 G0811403 2Q Q.OIL 87.30_ 6531 1.OQ_ 00811634 1650_ t17_ Q.015 830 53Q IQQ 00J8Th 1470 29 q.019 89.30_ 70.30 j.gQ_ 00511636 127 135 9.005 10.30_ 72.30 2.QQ_ 00811637 107L 34 0.ei 12.30_ 73.30 jflQ_ 00811638 1575_ 35 0JJ 13.30 7A30 LQ0 0081183L 1350 l85 Q.0iI 14.30_ 75.3Q 1.09_ 00811640 112L SL_ 9.02_ 1i30_ 7&3Q j.0O_ 00811641 1630_ ‘I& 9.02L 15.3Q Th00 0.7O 0081iS4 5410 34 9.021 55 — I 2008111103 Equity Exploration Consultants Ltd. °graphic log not to scale Page 4of13 I— I— “—‘I, I— I— If II I— Project: Taseko Hole Number: O8TSK-06 From To Rock-type & Description j From To Width Sample pm po 050 <@ 51.80 QZ-MO-CP Vein 45.00° 4.00mm> <@ 52.10 QZ-MO-CP Vein 15.00° 4.00mm <@52.10 QZ-MU-PY-MO Vein 150.00° 5.00mm> <@ 58.50 CL-MO-PY Siickenslide 70.00°> <@ 52.65 QZ-PY-MO (crustiform) Vein 65.00° 15.00mm> <@ 53.70 MG-CP-PY Fracture 70.00°> <@ 54.60 QZ-PY Vein 50.00° 5.00mm> <@ 54.90 QZ-CP-PY Vein 50.00° 13.00mm> <@ 55.16 QZ-MU-PY-CP Vein 80.00° 3.00mm> <@ 56.60 QZ-MO (margins) Vein 70.00° 5.00mm> <@ 56.70 MU-QZ-PY Vein 55.00° 3.00mm> <@ 57.90 CP-PY-MG Fracture 50.00°> <@ 58.40 QZ (CL selvage) Vein 60.00° 20.00mm> <@ 58.60 MU Fracture 70.00°> <@ 58.90 CL-CY Slickenslide 35.00°> <@ 59.09 QZ-PY-CP-MO Vein 65.00° 5.00-9.00mm> <@ 60.25 QZ Vein 55.00° 3.00mm> <@ 60.70 PY-MG Fracture 60.00°> <@ 60.90 CP-PY Fracture 55.00°> <@61.80 MG-PY-CP Fracture 50.00°> <@ 62.10 QZ-PY Vein 50.00° 2.00mm> <@ 62.80 QZ-MO-PY (MO at margins) Vein 70.00° 20.00mm> <@ 63.00 QZ.PY Fracture 70.00°> <@ 63.20 02 (crustiform, CL selvage) Vein 50.00° 6.00mm> <@ 64.00 QZ Vein 15.00° 4.00mm> <@64.40 02 Vein 65.00° 5.00mm> <@ 64.80 02 (crustiform) Vein 60.00° 20.00mm> <@ 65.40 MU-QZ (CL-MS selvage) Vein 60.00° 3.00mm> <@ 67.90 02 (MS-CL-PY selvage) Vein 70.00° 3.00mm> <@68.10 QZ-PY Fracture 65.000> <@ 68.70 02 Vein 55.00° 2.00mm> <@ 69.30 QZ-PY Vein 60.00° 4.00mm> <@ 69.75 02-MO (margins) Vein 60.00° 8.00mm> <@ 69.48 02 (CL seivage) Vein 55.00° 1.00-3.00mm> <@ 70.10 02-MS Fracture 60.00°> <@ 70.60 QZ-PY-CP Vein 70.00° 5.00mm> <@ 71.80 QZ-CP (CL-MS selvage) Vein 70.00° 1.00mm> <@ 72.00 QZ-MU-PY Vein 70.00° 4.00mm> <@ 72.55 Massive QZ-CP Vein 40.00° 5.00mm> LOG 50 40 40 405 0 4 \ \45S 4 2008111103 Equity Exploration Consultants Ltd. °graphic log not to scale Page 5 of 13t)C Project: Taseko Hole Number: O8TSK-06 < 77.40 Q2-CP-PY-M0 Vein 50.00° 5.00mm> <i 77.60 QZ-CP-M0 (at margins) Vein 50.00° 7.00mm> <@ 77.90 QZ-MU-CP-PY (MS selvage) Vein 60.00° 6.00mm> <@ 78.10 QZ-MO (MS-CL selvage) Vein 50.00° 3.00mm> <@ 78.70 QZ-PY Vein 85.00° 2.00mm> < 78.90 QZ-PY-CP-MO Vein 30.00° 12.00mm> <i 79.00 QZ-PY (cross.cut by QZ.CP.PY.MO) Vein 30.00° 4.00mm> <c 79.65 CP.PY Vein 30.00° 1.00mm> < 79.90 02 (CL selvage) Vein 70.00° 4.00mm> <© 80.60 QZ.CP-MO Vein 67.00° 4.00mm> <@ 81.00 QZ-PY (MS selvage) Vein 60.00° 4.00mm> <@ 81.90 PY Fracture 35.00°> <i 82.20 QZ Vein 60.00° 8.00mm> <@ 83.80 02-MO Vein 70.00° 3.00mm> 85.50 QZ-PY (MU-MS-CL selvage) Vein 60.00° 6.00mm> 86.50 91.00_Granodiorite_______________ Coarse.grained, CL-altered granodiorite. Altered groundmass .pigmented black by secondary BI. Coarse.gralned granodiorite is interbedded with a fine-grained diorite (aiso MG-Bl altered). Sharp margins between the 2 lithologies. moderate-strong intensity. Suiphide content is dramatiaily I Equity Exploration Consultants Ltd. From To Rock-type & Description 73.10 QZ-CP (CL-MU selvage) Vein 50.00° 2.00mm> <@ 74.20 QZ-CP-PY-MO Vein 70.00° 12.00mm> <t 74.50 QZ--PY-CP-MO Vein 50.00° 2.00mm> <t 74.70 CY-MU Fracture 30.00°> 77.00 86.50_Breccia - H Core competency is good. Decrease in phenocryst size (because of alteration). Clasts are Bl.Si.altered andesite and 02 vein fragments. Large fine-grained, altered andesite ciast with sharp clast boundaries at 85.8-86.1 m. Moderate Si-alteration also. 02 veining crosscuts clasts, and breccia appears to include brecciated massive 02 vein material. Veining crosscuts ciasts and strong chloritizes the clast. CP.PY÷I-MO in matrix of breccia: 2-3% PY; 1.5-2% CP; and —0.5% MO. 02 veins contain massive PY-CP and MO (typicaily at r Veining imparts intense MS+I-CL alteration to the rock, bleaching of vein haloes. ° Magnetite 2.50°s a Biotite 2.50°seProximal to veins Sericite 2.50°sa Proximal to veins Chlorite 3.00*sa Chalcopyrite 2.O0%s a 77.00. 80.40 Pyrite 1.50%s a 80.40- 86.50 Pyrite 2.50%sa Molybdenite 0.01%s 80 85 *graphic log not to scale in the coarse-grained granodiorite. a Chlorite 3.00°> e Sericite 2.00*s e Silicification 2.00°se Pyrite 0.50%> s Chalcopyrite 0.30%> a Molybdenite 0.01%> <@ 86.80 QZ Vein 50.00° 10.00mm> <c 87.30 QZ-PY Vein 45.00° 4.00mm> <@ 88.40 QZ Vein 75.00° 1200mm> <@ 89.10 QZ-PY Vein 70.00° 5.00mm> <@ 90.45 QZ-PY Vein 20.00° 2.00mm> 91.00 159.10_Breccia - Hydrothermal(?) I Dark grey to black, polymictic, matrix-supported breccia with intervals of unbrecciated grey diorite. Core competent - GY on fractures. Matrix is fine-grained QZ-Bl-MG. Clasts are typically sub-angular with sharp margins and are comprised of: 95 —(I) Black, fine.grained, Bl-MG-altered andesite (locally porphyritic) (2) Grey, medium- to coarse-grained, porphyritic, Bl-Sl+!-MG -altered diorite (7-15% PF phenos, up to 15mm, squat, irregular margins) (3) Grey-green CL-altered granodiorite (4) QZ vein fragments Unit is variably magnetic dependent on abundance of different clast.types. 100. Several generations of QZ-PY+i-CP veining with intensive MS+/-CL selvages. Disseminated PY. Locally SI-altered (decrease in grain size and bleaching). 137.8 - 149.4 m: Decreased CP, CL replacing BI alteration, QZ-PY-MO vein cuts MO-QZ vein. los - a Quartz Veining 2.50°s a 91.00 -97.70 Silicification 3.50*> s Chlorite 3.00°>> Sericite 3.50*s> Pyrite 0.75%> s Chalcopyrite 0.20%> s 91.00- 149.40 Molybdenite 0.01%s s 91.00 - 105.00 Biotite 3.00°> >91.00-112.50 In clasts and matrix Magnetite 3.S0°os ll0_ a 97.70- 105.00 Chalcopyrite 0.10%> a 97.70-112.50 Pyrite 0.30%>> Chlorite 2.00*> >97.70-124.40 As vein selvages Sericite 2.50*9 >105.00-112.50 Biotite 2.00*9> Chalcopyrite 0.30%> >112.50-115.00 Biotite 1.00*9> Chlorite 3.50°>> Chalcopyrite 0.50%>> Pyrite Project: Taseko Hole Number: O8TSK-06 From To Rock-type & Description j — — — Cu Mo AuFrom To Width Sample ppm ppm ppm 50 0.50 50 40 °I° 110 5 0 4 1/ I,— I,— // 9O L \‘r A \° 9L00_ 92.00_ 4.00_ G0811657 94S__ 458__ D.005 9200 93.0L i00 8I165L 114Q Q.014 93.00_ 94.Q0_ I00_ 00811659 164Q_ Z41_ Q.015. 94.00_ 94.00_ &0_ 00811660 94,40_ 95.QQ_ j.Q0_ 00811661 tl.91L_ 1Z4__ 0.00L 95.OIL 95.00_ i0fl_ G0811662 234Q_ 61___ Q.05Z_ 95.00_ 97.00_ I.QQ_ 00811663 1520_ Z26__ 0.052_ 97.00_ 98.00_ I00_ 00811664 1270_ IZI_ 0.02L 97.00 98.0L 10G 040 98.00_ 90.00_ I00_ 00811666 79_ 140__ Q.0.14_ 99.00 100.00 1.00 1IL 12305_0.092 100.00 lDt00 1.0Q_ 00811668 ‘IOL_ IIL_ Q.0.11 IQiQO 102.0fl i00 08114S 6S4 09 0.0W 102.00 101.00 iQL_ G0811670 640._. 60__ 0.02_ 103.00 404.00 iOQ_ (0811671 822 8L_ Q.O1L 104.00 105.00 iOQ_ (0811672 lOSft_ 25_ 0.0W 105.00105.00 iQ0 8S 11i Q.022 105.00 107.00 1.0fl_ G0811674 1890_ 164_ Q.OIL 107.00 105.00 iQQ_ 00811675 93L_ ISL_ Oi2L 108.00109.00 i00 Q8116ZL 1680 1S4 0.IOL 109.00 11D0 1Q fl8111ZL 400 59 Qi4L 110.30 litSO iSQ_ 00811678 2400._ 6Q.___ 0.074. fltSO 111.30 tS0 081107L l66S 40 111.10 11410 iS0_ G0811680 198L 87___ 0075 114.30 110.10 1.S0. G0811681 1823_ 19S_._ 0.02S_ 110.10 111.30 i40._ G0811682 2340_ 64___ 0.O1L L80 110.30 tS0 Q8 1833 138 0.011 11tS0 120.30 tS0 081133 1335 3L 0.02 2008111103 Equity Exploration Consultants Ltd. *grsphic log not to scale Psge 7 of 13 .112.50-127.40 Magnetite 2.00°. .115.00-127.40 Chlorite 2.00°e Pyrite 0.30%. . 116.00- 169.10 Chalcopyrite 0.10%. . 12740- 137.80 Magnetite 3.00°.. Silicificatlon 1.00°. .127.40-159.10 Chlorite 1.00°.. Pyrite 0.10%. 120_ 137.80- 143.90 Silicification 2.00*. e 137.80- 159.10 Biotite 2.00°.. Magnetite 2.00*, s 149.40- 159.10 Sericite 2.00°. e Sillcificatlon 1.00°.. Molybdenite 0.03%. < 91.20 QZ Vein 10.00° 3.00mm> 125 <@ 94.00 PY-QZ Vein 80.00° 2.00mm> — <@ 95.70 02 Vein 50.00° 5.00mm> <@ 96.30 MO Fracture 60.00°> <@ 97.97 QZ-MO-CP-PY Vein 70.00° 8.00mm> <@ 99.80 QZ-MU-PY-CP-MO (MS selvage) Vein 40.00° 4.00mm> <@100.60 QZ-PY Vein 40.00° 5.00mm> 130_ <@101.90 QZ-PY Vein 75.00° 15.00mm> <@103.40 QZ-CP-PY Vein 60.00° 4.00mm> <@103.90 QZ-MO-PY (margins) Vein 65.00° 5.00mm> <@105.90 QZ-MU-CP-MO Vein 50.00° 50.00mm> <@105.50 QZ-PY Vein 450.00° 30.00mm> 135 - <@150.30 QZ-CP-MO (MO at margins) Vein 60.00° 80.00mm> <@106.70 QZ-PY-MO Vein 60.00° 90.00mm> <i 112.90 QZ-PY.CP Vein 50.00° 2.00mm> <c 113.70 QZVein 60.00°10.OOmm> <@116.30 QZ-PY (MS-CL selvage) Vein 30.00° 8.00mm> <@118.40 QZ-PY Vein 30.00° 4.00-6.00mm> 140_ <@118.70 02-MO Vein 70.00° 8.00mm> <@121.40 C1Z-PY Vein 60.00° 50.00mm> <@127.90 QZ-CP Vein 55.00° 6.00mm> <i 130.76 QZ-PY Vein 60.00° 10.00mm> <@131.90 QZ-PY-CP Vein 70.00° 9.00mm> <@133.60 QZ-GY- PY Vein 85.00° 7.00mm> — <@137.20 02 Vein 30.00° 6.00mm> <@137.7002 Vein 60.00° 30.00mm> <@139.70 QZ-MO-PY-CP (crustiform, CL.MS selvage) Vein 60.00° 11.00mm> <@137.80 CL-GY Fracture 30.00°> <@143.20 02-MO Vein 70.00° 33.00mm> 150.. <@143.90 GY-QZ-PY-MO Vein 75.00° 2.00mm> Project: Taseko Hole Number: O8TSK-06 Cu Mo AuFrom To Rock-type & Description From To Width Sample 0 53 0 40 119.30 12080 t50 G08116850 30 ê \ \r. r \ \, i20.50. 122.30 t6Q_ G08l1686 202L 59_ 0.Q34_ i22.3 123.50 t6Q_ (08116S7 23.OL. 59.. Q.Q3L 122.80 125.30 1.SQ C0811688 206L.. 12. °.04L 1.25.3k 126.50 LSL. 130511559. 29Q9 liQ_ °40L 126.5k 128.30 140_ (0R11690 186L 50__ °t.53L 128.3 129.50 t5P_ G0811691 223L SL_ A.04L 12S.5 j3j.3Q 40_ 00811692 165L 54._ .Q41 i3i3 132.50 L5Q_ 00811693 255L 9L t05.L 132.5k 134.30 1.50_ 00811694 1705 74 0.OSL 134.3 136.50 t50 0S11495 1320 25 0.52L 1354 137.30 tSL_ cosiiss& 1810.. 5L 004L 137.3k 135.50 1.50_ 00811697 125 IIL_ 0.60L 135.S 140.30 tSL.. GQ51169&. 1495_ ISL_ fl04L 140.3k 141.50 1.50_ G0811699 145L SL_ ft3SL 14j.5 14140 0.OL 00811700 44t5 14340 L5Q 0Siil0L 1245 fl& O04L 143.3 144.50 tSQ_ 00811702 144L SL_ ‘1.069.. 144.5 14540 fl 00Mi260 1560 35 ‘1.048- 146.3& 147.50 1-50— 00811704 146L. 4L_ %055 146.35 147.80 t5Q_ 00811705 142.8514940 t50 051i70L t795 60 149.35150.80 160 il5Z 1500-67_0.D84 150.85 152.30 t5Q_ 00811708 149j.. St_ %DSL 152.35 153.80 1.50- 00811709 2120- 5L_ ‘1.058- 153.85 156.30 1.50_ 00811710 2580- 54__ Q.QSL 155.35 156.80 1.50- GOSII7II 241L. IQL_ r5.OSL 155.55 158.30 UL 00911712 155L 54__ ‘1.088- L : 2008111103 Equity Exploration Consultants Ltd. °graphic log not to scale Page 8of 13 <@146.10 GY (cutting QZ-PY) Vein 60.00° 2.00mm> < 147.10 QZ-PY Vein 50.00° 1.00mm> <@148.90 GY Fracture 50.00° 3.00mm> <l 151.87 MU-GY-PY Vein 70.00° 3.00mm> <@154.50 MU-QZ Vein 55.00° 4.00mm> <@154.90 QZ-PY-M0 Vein 70.00° 10.00mm> <@157.40 MS-PY-CP-MG Fracture 65.00°> <l 159.14 PY (MS selvage) Vein 60.00° 5.00mm> 159,1Q161.OO_Andesite I Coherent, fine-grained andesite; gradational contact with breccia. Core competent. >30% fine-grained FP phenos. CL-altered with silicified areas, less MG than breccia above. Finely disseminated PY & CP. QZ veining with selvages of MSIGY? (soft, white mineral, doesnt fizz with HCI), typically —50-70 to core axis. 160_ a 159.10- 160.00 Chlorite 1.00°ssss 160.00- 161.00 Proximal to veins Silicification 2.00-3.00°ca Chlorite 2.00°c <@160.60 QZ-M0 Vein 50.00° 4.00mm> <@161.45 QZ-M0 Vein 70.00° 4.00mm> <@162.60 QZ-FP-M0 (margins) Vein 60.00° 21.00mm> j6jOO178.9O_Breccia - Hydrothermal(?) I Polymlctic breccla with MG+1.Bl matrix, as above. Core competent. Strongly magnetic; highest within clasts of fine-grained, altered andesite. Fragmented QZ veins (10% of clasts). Clasts are sub-rounded to angular, and QZ veins cross-cut clast margins. Matrix is comprised of comminuted rock and crystal sos — fragments. Sections of less magnetic diorite lower in the interval. a 161.00- 177.80 Magnetite 3.50°ssa 177.80- 178.90 Magnetite 2.50°c a Pyrite 0.30%c a Molybdenite 0.03%ss c Chalcopyrite 0.10%c <@164.10 QZ-PY-M0 Vein 60.00° 10.00mm> <@167.30 QZ-PY-M0 Vein 85.00° 2.00mm> <@170.70 QZ-PY-M0 Vein 80.00° 8.00mm> <@172.10 QZ-MO-PY Vein 70.00° 12.00mm> < 171.30 QZ-PY-CP-M0 (margins) Vein 85.00° 20.00mm> <s 176.30 QZ-PY (MS selvaqe) Vein 70.00° 3.00mm> Project: Taseko Hole Number: O8TSK-06 — CuMo AuFrom To Rock-type & Description From To Width Sample 0 50 0 3 0 0. 155_ 0 4 156.3C 156.50 t50 0S1Ili 45D 2SL 156.8l 151.30 1.SQ_ G0811714 316L. ISL_ 0.12L \‘r \ \ \ .4.5 tv C 170_ 175_ 162 t5Q GQSJI1IS 3510 284 6.09L 162.5 154.30 tSQ_ 00811716 3ZItL 1iL_ 0..ISL 164,3 156.46 tSQ_ G0811717 Z450_ 3L._ 0.IL_ 165.54, 167.30 1.50_ 00811718 247L. SL_ 0.Q9_ 167.34, 155.50 t5Q_ 00811719 265L_ 8L_ 0.1SL 165.8k 17Q 0 G051Il2 4610 160 6.20L 1.70.34, 11180 1.S0_ G081i721 1600 8Z 6.072_ 171.54, 117.30 1,50_ 00811722 299L 13L_ Q.032_ 113.30. 114,46 tSQ_ 00811723 1520_ 12L_ Q.03L 174.50. 116.30 1.SQ_ 00811724 1160 66 Q.01i 174.50. 116.46 t5L.. G0811725 176.30. 117.50 1.50_ 00811726 1300_ 14 0.325_ 177.54, 118.46 110 G0811727 151L 44.L_ 0.02_ 2008111103 Equity Exploration Consultants Ltd. *graphic log not to scale Page 9 of 13 <@177.50 QZ-PY (margins) Vein 60.00° 50.00mm <@178.90 Between Breccia - Hydrothermal(?) and Andesite Contact 60.00°> 178.90 214.00_Andesite I Black andesite with dykes of green-grey diorite, core competent. Andesite is 180 - flne.grained with <1 mm FP phenocrysts, SI-altered, and is moderately to strongly magnetic. QZ veins with MU-MS or MS-CL-HE-EP selvages, PY+/-CP vein also minor QZ-DOL-GY and QZ-MG-CL veinlets. Fracture planes are coated with CL+I-PY-CP. Disseminated PY through both units. 186-201.3 m: Planar-sided dykiets of diorite, CL-MS+i-Sl-altered. Crackle 185_ breccia from 200.3 -200.6 m; QZ veins with KF alteration. 20t3-214 m: Dykes of porphyritic diorite, as above. CL after HB and altering matrix. QZ veins cut contacts. a Magnetite 3.00°a a Silicification 7.00°sa Proximal to QZ veins Sericite 190 2.00°sa Fractures Chlorite 2.50*55 Quartz Veining 3.00°sa Pyrite 0.30%sa Chalcopyrite 0.10%s <@179.40 QZ-GY Vein 60.00° 2.00mm> <@182.40 QZ-PY (MS selvage) Vein 50.00° 5.00mm> <@186.30 QZ-GY-MU-CP Vein 60.00° 4.00mm> <@195.00 QZ-GY-HE Vein 65.00° 10.00mm> <@196.10 QZ FP-CP-PY Vein 70.00° 3.00mm> <@197.60 QZ-PY (CL selvage) Vein 65.00° 3.00mm> <@201.14 QZ-GY-MG Vein 70.00° 27.00mm> <@207.60 QZ-MG-PY (MS selvage) Vein 60.00° 5.00mm> <@207.90 QZ-GY-MO Vein 60.00° 2.00mm> <@209.80 QZ-MG Vein 55.00° 2.00mm> <@210.30 QZ-PY-MO Vein 70.00° 15.00mm> Project: Taseko Hole Number: O8TSK-06 — ——From To Rock-type & Description Cu Mo AuFrom To Width Sample ppm 0 0. 0 40 40 0 4\cf \° \f\‘r \ I, 50 1] 0 00 195_ 200 205_ 210_ 118.90 180.40 I.80 G0811728 1.440_ 57__ 022 180.40 181.80 i.80_ G0811729 1140 4_ %OIL 18.t90 183.40 I.80_ G0811730 1290_ 32__ %OL_ 143.40 184.80 i40_ G0811731 1180_. 2___ .02_ 164.80 1660 1SQ 081il3 1059 89 185.40 187.40 t80_ G0811733 695_ 1iL_ Q.OQS 167.60169.80 i.8 08Ii14 2140 148 189.40 190.40 j.59_ G0811735 889_ 4L__ fl.81L 1SQ.40 182.30 i.50_ G0811736 1290_ S9___ %022 192.30 193.40 tS0_ Q0811737 2018.. 1iL_ i.042. 183.80 188.30 t80_ G0811738 1390_ 140__ 0.828 195.30 196.80 ISIL_ G0811739 115Q_ 104._ Q.024_ 198.40 196.40 8.00_ G0811740 198.60198.80 i.80 Q81i24L 1090 8L flAiL 198.40 199.80 t50_ (20811742 lSiQ_ 104_ °.04._ 189.80 201.30 I.89_ G0811743 2990_ 114__ 0.843. 201.30 202.80 tS0_ G0811744 2470_ 67___ 0.008_ 201.30 202.40 t50_ G0811745 20280 204.40 ISL_ G0811746 655_ O.0Q6 204.30 205.40 t50_ (20811747 842_ 18___ flAOL 205.40 207.80 15Q_ (20811748 ZSQ_ 52___ Q.O1L 207.40 208.80 tSQ_ G0811749 1210_ 164__ Q.01L 206.80 210.40 i.5L_ (20811750 754_ 57___ 0014 210.30 211.80 i.80_ (20811751 778_ -57____ Q.009_ 21180 tl3.30 1.80_ G0811752 708_ 98__ 0&L_ 210.40 214.40 150_ G0811753 882_ 254_ 0.01i 214.60 216.20 i.80_ (20811754 540 84__ 0.OOL 216.30217.80 180 081I25L 878 91 0.0Th -a 1 214.00 219.50_Diorite I Coarse-grained, porphyritic diorite with small (up to 25 mm), sub-angular 2008111103 Equity Exploration Consultants Ltd. *graphic log nottoscale Page Project: Taseko From To Rock-type & Description xenoliths of andesite. —30% FP phenocrysts, obscured by alteration - mottled appearance. Diorite is CL-altered with minor MG-alteration; CL after MG(?) an5— BI. Where alteration Is strongest only 10% PF phenos seen. QZ+1-PY veins. s Quartz Veining 3.00°es Chlorite 2.00°na Magnetite 1.00*55 Sericite 2.00°se Pyrite 0.50%ss Chalcopyrite 0.10%>> <@215.90 QZ-PY-CL Vein 40.00° 5.00mm> <@216.70 QZ-PY (margins) Vein 70.00° 10.00mm> <@218.90 QZ-GY Vein 90.00° 2.00mm> <@219.50 Between Diorite and ANDS; sharp, planar Contact 40.00°> 2195Q_235.O0_Andesite_______________________________ Black, fine-grained, feldspar-phyric andesite, as before. Core competent Moderately magnetic. Irregular QZ-PY veins with CL-MS-PY selvages (<1 -65 mm wide). s Magnetite 3.00°seln areas of Intense veining Chlorite 3.00°oe Quartz Veining 3.00°s 225_ <@222.26 QZ-PY Vein 90.00° 15.00mm> <@222.87 QZ-PY-CL (centre-fill) Vein 60.00° 10.00mm> <@225.00 QZ-PY Vein 80.00° 2.00mm> <@228.30 QZ-PY-MO.AC Vein 70.00° 10.00mm> <@231.10 GY Vein 40.00° 2.00mm> <@233.50 QZ-CL-HE (CL selvage) Vein 55.00° 20.00mm> <@233.70 QZ Vein 65.00° 35.00mm> 235.00 256.50_Andesite I 235_ Black, fine-grained andesite with fine-gralned squat FP phenocrysts. Core competent MG+I-Bl-altered. QZ+I-PY veins with bleached CL selvages, core fractures along veins. Veined core has pseudo-brecciated appearance. Interstitial PY and trace CP. 240_ ii Magnetite 3.00°s Chlorite 2.00*ss 235.00- 241.60 Pyrite 0.30%ss 241.60- 256.50 Pyrite 0.50%o*i 235.00- 247.70 Chalcopynte 0.10%ss Molybdenite 0.01%s*i 247.70- 256.50 Chatcopyrite 0.50%ssmo 0.03%s <@236.87 QZ Vein 70.00° 20.00mm> 245_ Hole Number: O8TSK-06 0 40 500 5045 4 From 0 4 To Width 217.80 218.80 1.00 Cu Mo AuSample ppm ppm ppm G0811756 483 66 <0005 L lasso> ,lconn inn145 nfl III lfl I Cfl flnei 4757Ill Ifl I2’2 Sn II— II \/ I,— /7 ,// 7/— 7/ /7%, 7/ ifl,n I’> en a en Ce 024 11421% ICn 094 In fl file CA SAC fl file SC laIn n nie 230_ 227.30 228.80 1.50 G0811763 1640 1.50 228.80 230.30 1.50 G0811764 1480 230.30 231.80 194 0.026 G0811765 65 231.80 233.30 0.036 1.50 233.30 234.80 1.50 G0811766 1080 39 0.031 G0811767 826 1.50 G081176a 38 1820 0.015 79 0.04 4— 348G 3S30 tSQ_ G0811769 l0ZQ_ 60___ 0.021 230.30 23L8Q L50 GQSIiIZ0. 12Z0 22140230.30 t30 00511271 00 0.021 230.30 30Q.0Q 00511121 1Q Z2 Q.03 240.80 ‘AZ0 180 00301271 1260 Th 0.011 2420 45Q 40 30fl7 130 47 Q17 243.40 4L30 111 G0811775 1420_ 143_ QJt22 240.30 246.30 tSQ_ G0811776 t470_ 5L__ 0.021 240.80240.30 t3 00301271 W90 - %11 245.30246.30 t50 00311771 410 -o2 0.021 240.40 ‘.6130 L3Q_ (30811779 ‘.510_ Z_._ Q.031 243.40 241.30 tS3._ (30811780 2008/11/03 Equity Exploration Consultants Ltd. *graphic log not to scale Page 11 of 13 a Chlorite 2.00*), a Magnetite 1.OO*sa Pyrite 0.50%s a Pyrite 3.00%a a Sericite 3.00°ss a Chlorite 3.00*s // l// I,— II // ‘I/f // /f— II ‘I/f f/i //%‘l/f f/i // ‘I/f f/i If \\j f/i II ‘I\IJ I/i f/i // I/i 1/ \\// /) Project: Taseko Hole Number: O8TSK-06 From To Rock-type & Description j From To Width Sample ,Upm pn i <@237.40 QZ-FP-MO (margins) Vein 50.00° 6.00mm> <@240.90 QZ-CP-PY Vein 80.00° 5.00mm> <@243.00 QZ.CP-PY (centre-fill) Vein 85.00° 10.00mm> <@245.45 QZ.PY-CP (centre-fill) Vein 50.00° 35.00mm> <@246.85 QZ-GY-PY Vein 80.00° 6.00mm> <@253.77 QZ-GY-CP-MO Vein 45.00° 6.00-15.00mm> <@256.40 GY (QZ.PY-MO at margins as stringer) Vein 80.00° 13.00mm> <@256.80 Between ANDS-DIOR, sharp Contact 80.00°> 1 S )O 5 0 4 250_ 255_ 25130 25250 2340 74 0837 28Z50 54ft t50 08ii782 18 4L 254.30 255.5 j5Q_ G0811783 454L 4L_ 0.022 256.50 264.90_Diorite I Diorite with intervals of andesite. Gradational contact. Diorite is locally porphyritic with FP phenocrysts up to 7 mm. Both are MG-Bi-altered; alteration locally obscures porphyritic texture. Dense QZ veining - QZ-MO veins with MO at margins of veins (1 - 12 mm wide, typically 50-70 or 10 to core axis). 265_ ° 256.53.260.50 Magnetite 1.00°sa 260.60- 264.90 Magnetite 300*aa Pyrite 0.50%sa Molybdenite 0.03%s <@260.14 QZ-MO (margins) Vein 65.00° 12.00mm> <@261.80 QZ.MO (CL selvage) Vein 60.00° 4.00mm> 264.90 269.80_Diorite 265- Locally porphyrltic diorite with angular xenoliths of fine-gralned andesite. PF phenocrysts are MS-altered. Weak MG alteration, overprinted by moderate CL alteration, which obscures porphyritic texture In places. Pervasive alteration of the saccharoidai-textured matrix. QZveinlng. 255.80 256.80 1.00 26&80 26680 tOO 1105 222 0.012 25680 258.30 1.50 25830 25980 150 25850 25130 Ian GORI 1757 1250 44 Rl 38 ean Ian 579 0009 17 an 254 38 1 50 1395 nn1 LJUOI 1lo 5-3 lien 0815 LU5II lag 252 4355 0 4 5 0 812 Ac 5 5 8 nie 0 4 \‘r \‘r <@267.79 QZ-QZ -PY Fracture 65.00° 20.00mm> <@270.30 PY-CL Fracture 65.00°> 265.80 267.30 264.30 265.80 1.50 “°“1 632 67 <0005 1.50 25730 259R0 Z50 702 51 269.80 274.10_Feldspar Porphyry I 270 Feldspar porphyry dyke, core competent. 25% FP and HB phenocrysts In a — saccharoidal-textured matrix. Pervasive MS alteration. Ha are CL-altered. FP phenos strongly MS-altered. Up to 3% dIsseminated PY. Low density of QZ veinlets (only several microveinlets). PY on fractures. 497 <0005 75 <A_nba 269.80 270.30 0.50 270.30 27t80 t50 flflO4l 764 271.50 273.80 2.00 894 noa78l 167 189 <0005 14 ISO <0.005 7 <0.005 2008111103 Equity Exploration Consultants Ltd. °graphic log not to scale Page 12 of 13 274.10 278.40_Diorite I Coarse-grained, porphyritic diorite. Core competency Is moderate; some core loss. Angular xenoliths of black, altered, fine-grained andesite. Intense, 275... pervasive CL-alteration, Imparts green hue to core, Intense QZ-CP-PY+I.MO veining. e Pyrite 0.50%s e Chalcopyrite 0.30%s a Molybdenite 0.01%s <@278.26 MIlky QZ-CL-CP-PY Vein 30.0r 6.00mm> <@278.40 PY-coated Fracture 56.00> 27L40_304.80_Andesite I Black, fine-grained andesite. Core competent Intense QZ.PY-CP.MO veining (1 - 280_ 35 mm). Larger QZ veins have MO in centre as fine stnngers. Coarse CP and PT interstitial in areas where veining creates brecciated texture. CL-alteration around intense veining. a Pervasive, patchy Magnetite 3.00*55 Chlorite 2.00*50 278.40- 287.30 Pyrite 0.30%ea 287.30- 292.00 Pyrlte 0.50%s** 292.00- 304.80 Pynte 0.01 %ao 278.40-292.00 Chalcopyrlte 0.10%s a 287.30- 292.00 Molybdenite 0.01%e <@283.10 QZ-CP-MO (margins) Vein 70.00* 27.00mm> <@284.90 QZ-MO (centre) Vein 55.00* 55.00mm> <@287.90 QZ-CP-MO Vein 70.00* 40.00mm> <@290.60 QZ (CL selvage) Vein 30.00 5.00.10.00mm> <@295.20 QZ Vein 80.00* 5.00mm> <@298.30 QZ-MO Vein 50.00* 30.00mm> Project: Taseko Hole Number: O8TSK-06 From To Rock-type & Description From To Width Sample pm Om pi 555 5 50 5 5 0 4 273.80 274.80 1.00 0811797 291 16 <0.005 \ ‘9 -.,1’ I— ‘9— 5 45 4 274.8 276.30 I40_ G0811798 634__ 74__ <0,995 276.3k 277.25 I.95_ G0811799 77L 35_ <0.005 zz azzo o i0L 429. 4 ZZL8 279.40 Q.9L 05iIQL 95L 275.4e 279.00 I.50_ G0811802 789 42____ 0.005 27 281.40 1.SL (30811803 1.248_ 6L__ 0.01_ 25Z,9 284.40 i8L Q8iI4Q4 85L 57_ 0.996. 282.9k 284.40 i.8Q_ G0811805 284A 284.90 iSL 08U80L l57 29L 0.906. 285.0 287.40 I.80_ G0811807 1315_ 12t__ 0.916. 2L4 284.90 I8Q 08fl80L 90 93_ 9.0D 286.0 309,40 j.99. G0811809 825__ IZZ_ 0.995 29.0.4c 291.90 iSQ_ G0811810 S8L 196. 9.005 201.00 293.40 L80_ GOSlIRIl 1148_ WL_ 9.006. 293.40 294.00 i.80_ G0811812 710 5..6.___ 0.Q05 294.00295.40 18Q 98iI9i3 1384 9.943. 295A 297.90 t59 Q81i8I4 59L 12L 0.916. 297.90 299.40 I.SL G0811815 744_ 74_ Q.91__ 209.40 399.90 i.8Q_ G0811816 804_ 36____ Q.914 300.00302.40 t50 081i81L T$L 90 9.906. 302.40 399.90 j.5Q_ G0811818 1055_ 63._ 0,999 303.90 304.80 0.SQ._ G0811819 1448_ IQ1_ 9&L_ 304.40 304.80 9.OL_ GORIIS2O 290,., 295_ 350_ \ naxn nxn PflH I 2008111103 Equity Exploration Consultants Ltd. *graphiclognottoscale Page APPENDIX 2 FULL DATA SET FOR GEOCHRONOLOGY STUDY 215 Geochronology detailed methodology Zircons were analyzed using laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) at the PCIGR at the University of British Columbia. Zircons were handpicked from the heavy mineral concentrate and mounted in an epoxy puck along with several grains of the P1eovice zircon standard (Sláma et al., 2007) and brought to a very high polish. High quality portions of each grain free of alteration, inclusions, or cores were selected for analysis. The surface of the mount was washed for 10 minutes with dilute nitric acid and rinsed in ultraclean water prior to analysis. A New Wave UP-213 laser ablation system and a ThermoFinnigan Element2 single collector, double-focusing, magnetic sector ICP-MS was employed for the analyses. The analytical methodology employed is modified somewhat from that described by Chang et al. (2006). Line scans rather than spot analyses were employed in order to minimize elemental fractionation during the analyses. Backgrounds were measured with the laser shutter closed for ten seconds, followed by data collection with the laser firing for approximately 29 seconds. The time-integrated signals were analyzed using the GLITTER software, which automatically subtracts background measurements, propagates all analytical errors, and calculates isotopic ratios and ages. Corrections for mass and elemental fractionation were made by bracketing analyses of unknown grains with replicate analyses of the zircon standard. A typical analytical session consists of four analyses of the standard zircon, followed by four analyses of unknown zircons, two standard analyses, four unknown analyses, etc., and finally four standard analyses. Final interpretation and plotting of the analytical results employ the ISOPLOT software (Ludwig, 2003). Interpreted ages are based on a weighted average of the individual calculated 207Pb/6 ages. 216 Table A.2 4°Ar - 39Ar geochronological dataset Laser Isotope Ratios Power(%)1 40Arfl9r 38ArI9r 37ArI9r 36Arfl9r CaIK CIIK %40Ar atm f 39Ar OAr*I39ArK Age ± 2a O6LH-HUB-36 - Biotite J = 0.010060±0.0000022; volume 39ArK =3131.53; integrated age = 79.35 ± 0.26 Ma 2 566.900±0.013 0.441±0.029 0.124±0.039 1.945±0.021 0.905 0.014 101.41 0.06 -8.052±9.881 -152.39±195.13 2.3 66.857 0.008 0.102 0.025 0.035 0.063 0.224 0.020 0.6 0.011 99.09 0.52 0.578 1.250 10.46 22.56 2.6 12.710 0.006 0.050 0.016 0.007 0.025 0.030 0.018 0.136 0.007 69.5 4.12 3.829 0.164 68.18 2.87 2.8 5.895 0.004 0.046 0.012 0.004 0.045 0.005 0.019 0.072 0.007 24.38 6.89 4.403 0.034 78.19 0.59 3 5.074 0.005 0.047 0.010 0.003 0.036 0.002 0.028 0.059 0.007 9.55 8.62 4.535 0.026 80.49 0.45 3.2 4.894 0.004 0.048 0.011 0.003 0.022 0.001 0.029 0.07 0.008 6.54 11.08 4.523 0.023 80.27 0.40 3.4 4.718 0.004 0.047 0.012 0.008 0.019 0.001 0.056 0.174 0.008 2.6 9.04 4.540 0.022 80.57 0.38 3.6 4.7150.004 0.0470.014 0.0060.019 0.0000.077 0.115 0.008 2.1 8.66 4.5600.022 80.91 0.39 3.8 4.6520.004 0.0460.010 0.0040.029 0.0000.089 0.086 0.007 1.34 11.19 4.5370.021 80.52 0.37 4 4.6240.004 0.0470.009 0.0050.019 0.0000.077 0.099 0.008 1.18 14.25 4.521 0.020 80.24 0.34 4.2 4.6370.004 0.0480.010 0.0080.021 0.0000.056 0.176 0.008 1.24 11.3 4.5280.020 80.36 0.34 4.4 4.646 0.004 0.048 0.016 0.007 0.018 0.000 0.091 0.14 0.008 0.97 8.08 4.544 0.020 80.63 0.35 4.6 4.658 0.004 0.049 0.012 0.006 0.032 0.000 0.102 0.129 0.008 0.81 6.19 4.556 0.021 80.85 0.37 O6LH-HUB-38 - Biotite J = 0.010066±0.000002; volume39ArK=3426.14; integrated age 77.86±0.23 Ma 2 121.408±0.010 0.114±0.059 0.096±0.049 0.410±0.019 1.558 0.005 99.74 0.17 0.289±2.061 5.25±37.33 2.2 21 .269 0.006 0.057 0.045 0.053 0.029 0.067 0.021 1.082 0.007 93.05 0.66 1.432 0.413 25.82 7.40 2.4 13.5040.005 0.0390.019 0.0140.030 0.0350.018 0.29 0.004 76.09 2.7 3.181 0.190 56.86 3.34 2.6 8.8240.004 0.0320.015 0.0070.022 0.0160.017 0.146 0.004 53.64 7.29 4.0450.083 72.01 1.44 2.8 5.202 0.005 0.027 0.012 0.003 0.034 0.002 0.025 0.05 0.003 13.7 10.52 4.440 0.028 78.88 0.49 3 4.798 0.005 0.027 0.018 0.005 0.030 0.001 0.030 0.094 0.003 5.35 9.35 4.489 0.024 79.73 0.42 3.2 4.648 0.004 0.027 0.015 0.005 0.028 0.001 0.077 0.113 0.003 2.7 7.32 4.466 0.024 79.34 0.41 3.4 4.606 0.004 0.027 0.012 0.004 0.029 0.000 0.039 0.075 0.003 1.65 12.78 4.481 0.019 79.60 0.34 3.7 4.599 0.004 0.028 0.013 0.006 0.035 0.000 0.094 0.123 0.003 1.65 10.38 4.472 0.021 79.44 0.37 4 4.5890.004 0.0280.012 0.0040.033 0.0000.070 0.076 0.003 1.26 11.71 4.481 0.021 79.59 0.36 4.3 4.5740.004 0.0290.011 0.0040.030 0.0000.055 0.091 0.004 1.16 11.03 4.471 0.019 79.41 0.34 4.6 4.5900.004 0.0300.015 0.0050.023 0.0000.085 0.1 0.004 1.12 8.17 4.4840.020 79.64 0.35 5 4.6000.004 0.0330.013 0.0070.028 0.0000.082 0.161 0.004 1.18 7.94 4.4900.020 79.75 0.35 -a Table A.2 40Ar - 39Ar geochronological dataset O6LH-HUB-45 - Hornblende J = 0.010078±0.000004; volume39ArK=177.82; integrated age = 69.17±2.21 Ma 2 85.305±0.012 0.188±0.068 0.121±0.066 0.279±0.030 1.139 0.028 95.39 1.17 3.826±2.299 68.25±40.25 2.3 20.165 0.005 0.047 0.046 0.110 0.033 0.056 0.033 2.207 0.005 80.12 5.91 3.885 0.551 69.28 9.65 2.6 41.478 0.009 0.053 0.039 0.165 0.018 0.129 0.018 3.687 0.003 91.23 15.47 3.591 0.657 64.14 11.54 2.8 11.706 0.009 0.027 0.036 1.137 0.016 0.030 0.030 26.306 0.002 63.87 12.29 4.152 0.270 73.96 4.72 3.1 6.4240.009 0.0180.046 0.6140.016 0.011 0.027 14.13 0 38.95 25.63 3.8370.098 68.45 1.71 3.3 4.948 0.010 0.016 0.045 0.453 0.016 0.005 0.056 10.36 0 17.25 19.03 3.947 0.097 70.38 1.69 3.5 5.372 0.008 0.019 0.056 0.531 0.017 0.008 0.063 12.022 0.001 21.88 7.25 3.865 0.146 68.94 2.55 3.8 6.708 0.009 0.034 0.047 1.415 0.017 0.015 0.050 32.793 0.004 39.09 8.26 3.885 0.229 69.29 4.00 4.2 9.411 0.009 0.081 0.041 2.411 0.015 0.0280.034 56.429 0.014 54.6 4.99 4.0640.282 72.42 4.93 O7LH-231-1 - Hornblende J = 0.005270±0.000008; volume39Ark =168.92; integrated age = 60.60 ± 0.54 Ma; 2 27.6317±0.0157 0.1898±0.0738 1.4742±1.0901 0.0727±0.0906 4.435 0.036 59.78 0.39 7.999±1.964 74.49±17.92 2.2 17.7348 0.0100 0.0856 0.1190 0.8586 0.6236 0.0420 0.0519 2.566 0.014 62.45 1.46 5.845 0.642 54.73 5.92 2.4 9.8563 0.0084 0.0469 0.0601 0.8388 0.2018 0.0154 0.1067 2.507 0.007 34.78 2.6 5.621 0.492 52.66 4.54 2.6 9.2075 0.0061 0.0351 0.0576 1.2592 0.1900 0.0108 0.0423 3.767 0.004 24 3.65 6.326 0.143 59.16 1.31 2.8 9.6066 0.0079 0.0384 0.1062 1.2984 0.0913 0.0109 0.1002 3.884 0.005 25.59 5.1 6.670 0.328 62.33 3.01 3 10.45390.0110 0.04760.1194 1.25450.2152 0.01230.2173 3.753 0.007 23.23 2.91 7.1840.797 67.04 7.30 3.2 9.7256 0.0091 0.1865 0.0354 2.5585 0.0368 0.0100 0.1078 7.666 0.039 21.73 6.24 7.208 0.326 67.26 2.99 3.6 7.80580.0068 0.35160.0232 5.22300.0184 0.00680.0928 15.694 0.078 13.58 13.39 6.5490.194 61.22 1.78 3.8 7.0989 0.0052 0.3484 0.0177 5.9932 0.0135 0.0051 0.0285 18.021 0.077 7.93 26.34 6.436 0.056 60.18 0.52 4 6.7853 0.0052 0.31 70 0.0127 6.3320 0.0135 0.0043 0.0318 19.047 0.07 4.49 30.51 6.394 0.054 59.79 0.50 4.2 7.2485 0.0114 0.2632 0.0168 5.4205 0.0331 0.0060 0.1826 16.436 0.057 5.68 5.68 6.324 0.337 59.15 3.10 5 8.50400.0166 0.3031 0.0840 4.61470.1285 0.01120.2510 14.007 0.066 7.6 1.74 6.2050.846 58.05 7.78 00 Table A.2 40Ar - 39Ar geochronological dataset O6LH-GO1 - Biotite J = 0.010093±0.0000062; volume39Ark=244.4; integrated age = 71.83 ± 1.32 Ma; 2 80.602±0.009 0.152±0.045 0.212±0.029 0.263±0.023 4.07 0.021 95.35 1.56 3.675±1.645 65.71±28.87 2.3 21 .281 0.006 0.070 0.023 0.135 0.020 0.062 0.030 3 0.01 84.6 8.44 3.209 0.543 57.50 9.57 2.5 13.848 0.007 0.048 0.037 0.097 0.030 0.038 0.018 2.136 0.006 78.56 10.89 2.897 0.204 51.99 3.60 2.7 10.175 0.006 0.044 0.023 0.132 0.024 0.022 0.029 2.969 0.006 61.08 10.06 3.848 0.193 68.74 3.39 2.9 7.983 0.008 0.057 0.050 0.269 0.018 0.014 0.051 6.186 0.009 45.52 9.52 4.203 0.213 74.95 3.72 3.1 6.8630.006 0.1570.019 0.6440.014 0.011 0.030 15.103 0.033 35.09 12.81 4.3370.101 77.29 1.77 3.3 7.165 0.009 0.202 0.016 0.784 0.015 0.012 0.039 18.431 0.043 36.97 12.6 4.405 0.150 78.49 2.61 3.5 6.4690.009 0.2530.014 0.9580.016 0.011 0.031 22.578 0.055 31.18 13.03 4.341 0.110 77.36 1.92 3.7 6.7040.008 0.271 0.016 1.0840.015 0.0120.025 25.608 0.059 33.09 13.28 4.3860.098 78.15 1.70 4 7.1920.012 0.201 0.028 0.8820.018 0.0130.039 20.711 0.043 37.78 7.8 4.3050.167 76.74 2.92 O6LH-039-1 - Horn blende J = 0.010089±0.000004; volume39ArK=216.69; integrated age = 21.74 ± 0.96 Ma; 2 56.072±0.016 0.154±0.091 0.197±0.051 0.194±0.033 1.707 0.024 98.28 0.55 0.873±1.817 15.83±32.78 2.3 8.7650.018 0.0620.053 0.0460.050 0.0270.060 0.511 0.01 86.15 2.95 1.0720.485 19.41 8.74 2.6 3.4890.006 0.1130.030 0.0580.058 0.0090.086 1.077 0.022 64.94 6.21 1.0560.228 19.12 4.11 2.8 5.1260.009 0.2400.023 0.1430.035 0.0150.041 2.976 0.052 76.2 5.01 1.0760.179 19.48 3.22 3 4.0860.006 0.3970.026 0.2970.021 0.011 0.077 6.641 0.088 63.53 4.57 1.2700.259 22.97 4.65 3.2 9.623 0.006 0.819 0.012 0.689 0.014 0.031 0.024 16.169 0.185 87.36 14.02 1.170 0.219 21.18 3.94 3.4 5.5580.006 0.7840.011 0.7830.014 0.0180.021 18.443 0.178 77.79 19.71 1.1840.111 21.43 1.99 3.6 3.303 0.010 0.675 0.013 0.801 0.015 0.010 0.029 18.869 0.153 58.13 20.66 1.312 0.084 23.72 1.51 3.8 1.6590.013 0.5920.017 0.851 0.018 0.0050.036 20.068 0.134 19.15 21.67 1.2290.053 22.23 0.95 4.1 1.8680.014 0.7930.022 0.7860.019 0.0060.147 18.416 0.181 13.52 4.66 1.1430.272 20.68 4.90 lntensity in the defocused beam of a 10-W CO2 laser 2The J-value indicates the irradiation flux for each sample, which was calculated relative to the neutron flux monitors (Fish Canyon Tuff saidine; 28.02; Renne et al., 1998) \Folumes are 1E3 cm3 NPT Table A2 - U-Pb Laser Ablation geochronology dataset Isotopic Compositions (Ia) Isotopic Ages (Ia) Sample number and rock type Fraction pb207!Pb6 Pb207/U35 Pb206!U38 Pb207IP6 Pb207!U35 Pb206IU38 1 0.05384 0.08313 0.01138 364.3 81.1 72.9 2 0.04847 0.07835 0.0117 122.5 76.6 75 3 0.04595 0.0746 0.01205 0.1 73.1 77.2 4 0.04582 0.074 0.01201 0.1 72.5 77 5 0.04704 0.07472 0.01152 50.9 73.2 73.8 O6LH-G02 6 0.05137 0.08278 0.01222 257.3 80.8 78.3 (Northern 7 0.05064 0.08221 0.01185 224.3 80.2 75.9 Charlie dyke) 8 0.05132 0.08614 0.01218 255 83.9 78.1 Location: 9 0.04371 0.07306 0.01214 0.1 71.6 77.8 (4553353mE, 10 0.05245 0.0852 0.01219 305.2 83 78.1 5669938mN) 11 0.05195 0.0846 0.01167 283.3 82.5 74.8 12 0.04941 0.08049 0.01192 167.4 78.6 76.4 13 0.05218 0.08379 0.01147 293.5 81.7 73.5 14 0.05007 0.07997 0.01225 198.4 78.1 78.5 15 0.0492 0.07959 0.01209 157.3 77.8 77.5 16 0.04711 0.07568 0.01178 54.6 74.1 75.5 1 0.04882 0.07931 0.01253 139.1 77.5 80.3 2 0.04956 0.08503 0.0124 174.5 82.9 79.4 3 0.05023 0.08678 0.01257 205.5 84.5 80.5 4 0.05464 0.09322 0.01262 397.3 90.5 80.8 5 0.04844 0.08467 0.01289 120.8 82.5 82.6 O6LH-GO1 6 0.05267 0.09442 0.0127 314.4 91.6 81.3 (Southern 7 0.05469 0.09656 0.0124 400.1 93.6 79.5 Charlie dyke) 8 0.04575 0.081 58 0.01307 0.1 79.6 83.7 Location: 9 0.05273 0.08797 0.01254 317.3 85.6 80.3 (453136mE, 10 0.0444 0.07909 0.01273 0.1 77.3 81.5 5669870mN) 11 0.05014 0.0853 0.01265 201.5 83.1 81 12 0.06327 0.10544 0.01201 717.2 101.8 76.9 13 0.05453 0.09503 0.01252 393 92.2 80.2 14 0.04507 0.07894 0.01291 0.1 77.1 82.7 15 0.0459 0.08057 0.01263 0.1 78.7 80.9 16 0.04925 0.08288 0.01265 160 80.8 81 220 Table A2 - U-Pb Laser Ablation geochronology dataset Isotopic Compositions (Ia) Isotopic Ages (Ia)Sample number and rock type Fraction Pb207IP6 Pb207IU35 Pb206IU38 Pb207IP6 Pb207IU35 Pb206!U38 1 0.0477 0.0791 0.0119 83.5 77.3 76.4 2 0.0475 0.0822 0.01 23 73.2 80.2 78.9 3 0.0482 0.0834 0.0124 111 81.3 79.5 4 0.0476 0.0857 0.0128 77.2 83.5 82.2 5 0.0495 0.0871 0.0128 170.7 84.8 81.8 6 0.0475 0.0833 0.0128 75.9 81.2 81.9 7 0.0484 0.0863 0.0130 120 84 83 O7LH-009 (Hub 8 0.0476 0.0807 0.0125 79 78.8 80.2 diorite) 9 0.0475 0.0842 0.0126 75.2 82.1 80.5 Location: 10 0.0477 0.0833 0.0129 80.9 81.3 82.5 (453430mE, 11 0.0477 0.0836 0.0126 81.7 81.5 80.5 5668870mN) 12 0.0491 0.0865 0.0129 151.3 84.2 82.9 13 0.0479 0.0815 0.0124 94.6 79.6 79.3 14 0.0480 0.0830 0.0126 98.7 80.9 80.5 15 0.0488 0.0898 0.0131 135.9 87.4 83.8 16 0.0479 0.0790 0.0124 92.1 77.2 79.3 17 0.0476 0.0838 0.0127 79.2 81.7 81.4 18 0.0485 0.0841 0.0126 123.1 82 80.9 19 0.0475 0.0795 0.0122 73.2 77.7 78 1 0.0463 0.0567 0.0092 14.2 56 58.8 2 0.0521 0.0630 0.0087 290.9 62 56 3 0.0477 0.0616 0.0093 82.1 60.7 59.7 4 0.0468 0.0591 0.0090 38.8 58.3 58 5 0.0481 0.0609 0.0091 101.8 60 58.6 O7LH-238 6 0.0493 0.0625 0.0090 160.3 61.5 58 (Northwest 7 0.0541 0.0637 0.0087 373.7 62.7 55.7 Copper pluton) 8 0.0471 0.0585 0.0087 52.5 57.7 55.8 Location: 9 0.0476 0.0590 0.0089 79.8 58.2 57 (447595mE, 10 0.0472 0.0575 0.0088 56.2 56.8 56.5 5670561mN) 11 0.0469 0.0592 0.0091 42.9 58.4 58.3 12 0.0494 0.0600 0.0088 165.7 59.2 56.2 13 0.0468 0.0569 0.0088 37.2 56.2 56.5 14 0.0517 0.0614 0.0086 272.4 60.5 54.9 15 0.0498 0.0678 0.0097 184.6 66.6 62.1 16 0.0501 0.0585 0.0083 198.9 57.7 53.2 221 Table A2 - U-Pb Laser Ablation geochronology dataset Isotopic Compositions (Ia) Isotopic Ages (Ia)Sample number and rock type Fraction Pb207IP6 Pb207/U35 Pb206IU38 Pb207IP6 Pb207IU35 Pb206IU38 1 0.05406 0.10031 0.01344 373.3 97.1 86 2 0.04897 0.09557 0.0144 146.6 92.7 92.2 3 0.05996 0.11244 0.01319 602.2 108.2 84.5 4 0.06248 0.12262 0.01366 690.5 117.4 87.5 O6LH-HUB-45 5 0.04103 0.0759 0.013 0.1 74.3 83.3 (Feldspar- 6 0.04953 0.08263 0.01211 173.2 80.6 77.6 hornblende 7 0.04378 0.07511 0.01285 0.1 73.5 82.3 porphyry dykes) 8 0.0463 0.07788 0.01221 13.1 76.2 78.2 Location: 9 0.04934 0.08349 0.01227 163.9 81.4 78.6 10 0.05081 0.08848 0.01276 232.4 86.1 81.8 11 0.04579 0.07805 0.01257 0.1 76.3 80.5 12 0.05525 0.09147 0.01232 422.2 88.9 79 13 0.04938 0.09163 0.0129 166.1 89 82.6 14 0.0559 0.09404 0.01218 448.2 91.3 78.1 15 0.06152 0.10034 0.0122 657.5 97.1 78.2 222 APPENDIX 3 FLUID INCLUSION MICROTHERMOMETRY 223 APPENDIX 3 - Summary table of microthermometric data for fluid inclusions from quath vein samples from the Tchaikazan River area Sample Number Chip Number Type Tm (ice) Thtot Salinity O7LH-225 I L-V -1.2 154 2 O7LH-225 I L-V -0.9 128 1.4 O7LH-225 I L-V -0.8 131 1.46 O7LH-225 1 L-V -0.4 136 0.2 07LH-225 I L-V -0.8 128 1.4 O7LH-225 I L-V -1.1 132 1.3 O7LH-225 I L-V -1.5 154 2.47 O7LH-225 I L-V -1.3 129 2.24 O7LH-225 I L-V -0.9 109 1.43 O7LH-225 1 L-V -1.2 154 2 O7LH-225 I L-V -1.4 163 2.78 O7LH-225 1 L-V -1.3 147 2.2 O7LH-225 1 L-V -2.1 140 4.5 O7LH-225 1 L-V -0.4 150 0.86 O7LH-225 1 L-V -0.6 154 0.98 O7LH-225 1 L-V -0.3 149 0.18 O7LH-225 I L-V -2.8 1.63 2.78 O7LH-225 I L-V -0.7 143 5 O7LH-225 I L-V -1.2 145 2.1 O7LH-225 1 L-V -0.1 152 0.16 O7LH-37-2 I L-V -3 190 10 O7LH-37-2 1 L-V -2.9 193.4 10.1 O7LH-37-2 1 L-V -1.7 180.2 5.6 O7LH-37-2 1 L-V -2.8 180.6 7.2 O7LH-37-2 1 L-V -0.7 110 5.5 O7LH-37-2 I L-V -4.5 187 7.05 O7LH-37-2 I L-V -3.4 188.1 7.7 O7LH-37-2 1 L-V -2.9 183.2 7.4 O7LH-37-2 1 L-V -3 188 7.5 O7LH-37-2 2 L-V -2.7 180 5.7 O7LH-37-2 2 L-V -3.5 183 5.6 O7LH-37-2 2 L-V -2.3 178 5.6 fV7 I I I ‘I I ‘.1 .1 7 fl A 224 APPENDIX 3 - Summary table of microthermometric data for fluid inclusions from quartz vein samples from the Tchaikazan River area Sample Number Chip Number Type Tm (ice) Thtot Salinity O7LH-040 I L-V -2.9 169 5 O7LH-040 2 L-V -4.5 166 6.4 O7LH-040 2 L-V -3.4 176 4.7 225

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