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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  .  TABLE OF CONTENTS  ii 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  1.7  EXPLORATION  21  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  CHAPTER III  .35  42  GEOLOGICAL AND GEOCHRONOLOGICAL FRAMEWORK OF MAGMATIC-HYDROTHERMAL ACTIVITY IN THE TCHAIKAZAN RIVER AREA  42  3.1  REGIONAL GEOLGIC SETTING  3.2  LOCAL GEOLOGIC SETTING 3.2.1  3.2.2  3.2.3  -  42 FIELD OBSERVATIONS  Tchaikazan River Formation  43 44  Volcanic facies  44  Volcano-sedimentary facies  44  Sedimentary facies  45  Powell Creek Formation  46  Coherent facies  46  Non-massive facies  46  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  3.5  3.6  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  GEOCHRONOLOGY  55  Ar Geochronology 39 Ar40  56  U-Pb Geochronology  56  3.5.1 Discussion  57  FISSION-TRACK THERMOCHRONOLOGY  58  iv  3.6.1 3.6.2  Introduction Methodology  .58 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 5.3.1  5.3.2  99  The Hub Porphyry  100  Hydrothermal Breccia  100  Magnetite ± biotite alteration  100  Sericite alteration  101  Chlorite ± epidote alteration  101  Silicification  101  Charlie-Northwest Copper  102  Propylitic alteration assemblage  102  Phyllic alteration  103  Kaolinite—dickite—illite alteration (Advanced Argillic)  103  V  5.4  5.5  5.6  Quartz-diaspore assemblage (Advanced Argillic)  104  Silicification  104  PARAGENESIS  104  5.4.1  Hub  105  5.4.2  Charlie-Northwest Copper  105  ORE ASSEMBLAGES  106  5.5.1  Hub  106  5.5.2  Charlie-Northwest Copper  107  AGE OF MINERALIZATION  108  5.6.1  Hub  108  5.6.2  Charlie-Northwest Copper  109  FLUID INCLUSION MICROTHERMOMETRY  5.7  5.7.1  Sampling and analytical techniques  5.7.2  Description of fluid inclusions from the Hub  porphyry deposit 5.7.3  5.8  110 110  110  Description of fluid inclusions from the  Charlie-Northwest Copper area  111  5.7.4  112  Discussion  STABLE ISOTOPE STUDY  112  5.8.1  Sampling and analytical techniques  113  Carbonate stable isotope analyses  114  Oxygen and Hydrogen stable isotope analyses  114  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  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  Discussion and Interpretation  117  5.8.2  5.8.3  5.8.4  vi  CHAPTER VI  .144  GENESIS AND EVOLUTION OF THE MAGMATIC  -  HYDROTHERMAL  SYSTEM IN THE TCHAIKAZAN RIVER AREA  6.1  THE TCHAIKAZAN RIVER AREA  -  144  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  Table 3.2  Table 3.3  67  Summary of geochronological age dates from the Tchaikazan River area  81  Summary of collected thermochronology samples  85  CHAPTER V Table 5.1  Summary of the styles of mineralization and paragenesis  Table 5.2  Summary of the veins and hydrothermal alteration at the Hub porphyry deposit  Table 5.3  120  129  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  Figure 1.2  26  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)  Figure 2.2  Schematic relationships between depth and age-frequency distributions. From Kesler and Wilkinson, 2005  Figure 2.3  36  37  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)  Figure 2.4  38  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)  Figure 2.5  39  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)  Figure 2.6  40  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 Figure 3.2  61  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  Figure 3.7  Stratigraphic section through part of the Powell Creek dominated by resedimented units  Figure 3.8  66  68  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  Figure 3.11  Photoplate showing the igneous rocks attributed to the Northwest Copper pluton  Figure 3.12  71  72  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  Figure 3.19  79  Equal-area, lower hemisphere stereonet plots showing the orientation of veins in the Charlie-Northwest Copper areas  Figure 3.20  80  Ar-Ar plateau ages for representative intrusive rocks from the Tchaikazan River area  Figure 3.21  82  U-Pb geochronology diagrams for samples of intrusive rock from the Tchaikazan River area  Figure 3.22  83  Summary diagram for radiogenic isotope geochronology for the Tchaikazan River area  Figure 3.23  84  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)  Figure 4.2  94  Reconstruction of the volcano-sedimentary system within the Tchaikazan River area, including major facies associations and tectonic setting (Modified from Israel, 2001)  Figure 4.3  95  Schematic reconstruction of the volcanic facies of the Powell Creek Formation:  primary  volcaniclastic rocks  volcanic,  resedimented  volcanic  rocks  and 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  Figure 5.2  119  Map of the Hub porphyry trenches. Pervasive hydrothermal alteration is mapped,  including sericite-chiorite,  chiorite-epidote and biotite  magnetite alteration Figure 5.3  ±  121  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  Figure 5.6  Photoplate of other styles of alteration in the Hub porphyry deposit: sericite, chlorite-epidote, and silicification  Figure 5.7  127  Slab from the quartz diaspore area of alteration with textural and compositional features  Figure 5.10  126  Photoplate of advanced argillic alteration on the western flank of Ravioli ridge  Figure 5.9  125  Photoplate of the styles of alteration in the Charlie-Northwest Copper area  Figure 5.8  124  128  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  Figure 5.13  132  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  Figure 5.16  136  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  Figure 5.19  140  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  Figure 5.20  141  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  Figure 6.2  Schematic model for the establishment of a magmatic-hydrothermal system beneath the Ravioli ridge in the Northwest Copper area  Figure 6.3  153  154  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  .  If you canfiCCtuIe unforgIvIng mInute ‘WIth sIxty secon6s’ worth of distance run, yours Is the Earth anti everything 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 238 Pb 206 UAr; (4) X-Ray diffraction (XRD) and Shortwave Infrared (SWIR) spectrometry using 39 Arand 40 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, H 0, C0 2 , NH 2 3 , A1OH, FeOH, and MgOH) that 4 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  U ages. Errors for 238 Pb/ crystallization ages are based on weighted average of the calculated 206 the final interpreted age for each sample are given to the 2 sigma level using the method of Ludwig (2003). Mineral separates for 40 Ar analysis were hand-picked, washed in acetone, dried, 39 Arwrapped 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/cm /s. 2 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 CO 2 laser (New Wave Research MIR1 0) until fused. The gas evolved from each step was analyzed by a VG5400 mass spectrometer equipped with an ioncounting 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: Ar/ 40 ( Ar)K 39 36 = 0.3952±0.0004, Ca/K ( Ar)ca 39 Ar/  =  =  0.0302 ± 0.00006, ArI 37 ( Ar)ca 39  =  1416.4±0.5,  1.83±0.01 Arca/ 37 ( ArK).). 39  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 km 2 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 hightemperature (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 veinhosted 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  Deposit Commodities USA  • • •  El  El I El  Cu-Au Cu Cu-Mo Au  Deposit Size Mo W-Mo Ag  El 0  Large Medium Small  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).  0  Km 250  500  Key deposit tve OMI FOR INT CB INS  = = = = =  Omineca Foreland Intermontane Coast Insular  Alkaline porphyry • Calcalkaline porphyry • Past producer • Developed prospect O  Highland Valley  Copper Mountain  Figure 1.2: Map of British Columbia, with study area highlighting proximal magmatic-hydrothermal deposits.  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 copperbearing 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, Cubearing 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 threedimensions. 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 km 2 (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 km 3 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 AnnMason 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 with pyrite and minor molybdenite.  ±  bornite,  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 H 0; thus the principal 2 volatile in magmas associated with a porphyry deposit is H O (Burnham, 1997). Volatiles, such 2 as, HCL, HF, H S, SO 2 ,H 2 , and C0 2 , also play important roles during the separation of fluid from 2 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 singlephase 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 cm ). Williams-Jones and Heinrich (2005) present a model for the 3 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  A  1.4  • N. & C. Chile  Sar Chesmeh A S. & C. America 0 Grasberg USA/Mexico Escondida Escondid Eurasia Norte yu 0 SW Pacific Bingham 1 • Tolgoi t 0 • Rosario Los Pelambres • Rio Blanco Pima RayED La Granja Teniente • 0 Butte . A A Morenci-Metcalf 0 • Cujaone Chuquicamata Lone Star 0 A Toki ElCananea •Rad omiro Kal’makyr  1.2  o  1.0  0.8 ()  0.6 0.4  /  Tomic  Aktogay Aiderly  C. Colorado (Panama)  •N.&C.Chile 0 Eurasia AS.&C.America 0 SW 0 USA/Mexico Pacific  2,500  5,000  7,500  0.2 0.0  0  10,000  12,500  Tonnage (Mt)  B  100 M. Miocene Pliocene -  Eocene Oligocene -  80  Palaeocene eocene -  .  60  Palaeozoic  0 ci) C Cu C  40  0  0  20  0 ci) .  .. 0 IHIuniNnniu 1 • I 010 Cu  0 C.)  cDO  I— •5  9  )  C Cu  D  E  o  S  Cu  0) ci)  -.  -  .9  °  -  9 Cu  0 Cl)  0  O — Cu Cr) 0 0 C ‘  o  -J  0  C CD  C.)  E  ‘.-  Cuci) C  C Cl)  E  Cl)  Cu  0  •  > C Cl)  0  -  •  I  2 CuQ 9 -J  0 •0 Cu  C  (t,0 0  Cu C,) 0)j  Cu Cu  9  F  Cu  .  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  Increasing age  II Increasing age  15 10  Porphyry Copper deposits n = 455 Bin size = 2 m.y. Modal Age = 12 m.y.  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).  37  Asthenosphere  crystalline basement  Feeder dyke complex  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). 38  Key to hydrothermal zoning  D  PROPYLITIC ChI - Epi - Carb -Aib  Ii’ LJ  PHYLLIC Qtz-Ser-Py ARGILLIC Qtz-Kao - chi  D fl  POTASSIC  Qtz - K-feld  -  Bi -± ser ± anh  Qtz - sericite chlorite -Kfdspr  ii  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, Au: Gold, Bi: Biotite, Carb: Carbonate, Cp: Chalcopyrite, ChI: Chlorite, Epi: Epidote, Gal: Galena, K-feld: K-feldspar, Kao: Kaolinite, Mag: Magnetite, Py: Pyrite, Qtz: Quartz, Ser: Sericite.  39  0  I  2 km 3  4  5  6 Skarn (garnet diopside) Sodic-Calcic (oligoclase actinolite Potassic (biotite ± K-feldspar) -  -  -  sphene)  Weak biotite  Fluid flow pathway  Endoskarn (plagioclase diopside) Weak Sodic-Calcic (epidote sphene ± albite ± actinolite) Propylitic (albite epidote actinolite chlorite hematite) -  -  -  -  -  -  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 5km 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)  40  Low-density, salt-free, HC1 SO 2±H S-rich vapor 2 causes acid leached ‘vuggy’ quartz and advanced argillic alteration  Fumerole Stage  Generally barren Quiet degassing from internally convecting magma chamber  Ii  Legend  I I  I I  I I I  I I I  Advanced argillic alteration Phyllic alteration Cu-Fe sulph ides Barren potassic (+ magnetite) Solidified porphyry ± propylitic alteration Partially molten magma  Deeper-sourced expanding vapor extends acid leaching and advanced argillic alteration; vapor is metal-depleted by cooling and deposition at greater depth. Porphyry Stage  u1\  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 Epithermal Stage  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 H S So 2 2 Cu Au As-rich vapor from condensing hypersaline liquid rich in FeCI . Potassic 2 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).  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 pastproducing 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). contractional deformation (Dl) was dominant.  By Mid-Cretaceous time  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. Wellbedded 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 40 Ar dating on hornblende and provided ages for the base of the formation of 39 Ar94.6  ±  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 Ar40 and 238 ( Ar 39 Pb -zircon) constrained the age of the Hub diorite 206 Uto 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 40 Ar hornblende cooling age of 60.01 39 Ar-  ±  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 km 2 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 a 40 Ar 39 Arplateau 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 for 40 Ar analyses. 39 ArAges for intrusive samples (06-LH-HUB-36, 06-LH-HLIB-38, O6LH-HIJB-45, O6LHGOl, 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 40 Ar plateau ages (Figure 3.20) 39 Arwith results summarized in Table 3.3 and the full data set is in Appendix II.  Ar Geochronology: The Ar-Ar system is useful for dating the cooling ages of intrusive 39 Ar40 rocks.  The parent isotope 40 K decays to the daughter isotope 39 Ar.  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 40 Ar analysis 39 Arof 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). samples yielded suitable zircon fractions.  All  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  U (Dickin, 2005). Table 3.4 presents a list of all samples submitted for U-Pb analysis and 238 Pb/ 206 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 40 Ar analyses of biotite and 39 Arhomblende 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 238 U at a rate of 10’ a’ (Fleischer et al., 1975; Wagner and van der Haute, 6 1992).  Minerals such as apatite, zircon, and sphene contain the appropriate range in  concentration of 238 U 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 yielded a date of 31.4  ±  ±  4.7 Ma and AFT  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, 40 Ar, and ZFT data imply that the Hub diorite 39 Arcooled 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 5530 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  5?  51  Bralome fault systen  B  cc t I  Powell Creek Formation  Powell Creek Formation  Powell Creek Formation  Taylor Creek Group  Falls River Formation  Taylor Creek Group  Carpenter Lake  0 D 0  a)  C)  cc  a) C)  LI  Tchaikazan River Formation  0 0 0  cc  LI Jackass Mountain Group  Relay M untain Group a) C  -)  x  a) C)  0  a)  S  a)  cc  C-)  I  a)  cc -o cc  0 0  0  >  C  cc S  () a)  0)  a)  Tchaikazan River Area  C  cc  00  cc9  oa)  East Waddington belt  Northeast of Tchaikazan Fault  Figure 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 61  Insular and SWCB  w  Gambler Arc  Southeast Coat Belt  Intermontane Superterrane  Study area  F Tyaughton Basin  Methow Basin  Wrangellia and Western Coast Belt Cadwallader North America Continental mass Volcanic petrofacies Cherty petrofacies  Bridge River Terrane  Arkosic petrofacies  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.  CD  CD  -,  CD  CD N CD  CD  CD  -h  0  CD  3  CD 0 Co C, CD  0  -Il Co C 1 CD () ()  Key to the Geology of the Tchaikazan River area J Quaternary cover  E]  Intrusive rocks Northwest Copper syenite Unknown age Northwest Copper pluton Equigranular diorite; U-Pb = 57.33 ± 0.85 Ma Hub diorite Porphyriticdiorite/granodiorite, multiphase intrusion: U-Pb = 81.19 ± 0.78 Ma Tchaikazan Rapids Pluton U-Pb = 89.3 ± 1.4 Ma (Blevings, 2008)  -  -  -  -  -—  40  y  y  -  VV Powell Creek Formation: Massive fades Coherent andesite, to basaltic-andesite lava flows, volcanic breccias and plagioclase-phyric andesite. Minor volcaniclastic components. (3-4 km thick) __L__ Powell Creek Formation: Non-massive Non-massive volcaniclastic deposits; polymictic andesite breccias, lahar-like flow units, breccias with tuffaceous matrix. ••••  Taylor Creek Group Massive micaceous sandstone, conglomerates and black shale/mudstone. North of the Tchaikazan Fault (2-4 km thick) (not mapped in this study).  ......  Tchaikazan River Formation: Volcanic fades Coherent andesite lava flows, with minor andesite breccias/ volcaniclastic sandstones increasing towards the top of the unit (1 km thick).  -j  Tchaikazan River Formation: Volcano-sedimentary facies Coherent andesite lava flows, interbedded with mudstones, siltstones and sandstones, peperitic contacts observed (500m).  c  ii Tchaikazan River Formation: Sedimentary facies Interbeddeci cobble conglomerates, sandstones, siltstones and black shale/mudstones. Fossils locally developed (500m).---Relay Mountain Group Sandstones, siltstones, locally calcareous, fossil-rich conglomerates, including crinoid and bivalve components. A fossil collection was assigned an age of -136- 130 Ma (Israel, 2001) Not observed in the study area.  Bedding Thrust fault Identity and existence certain, location accurate. Sawteeth on upper (tectonically higher) plate -  Thrust fault Identity and existence certain, location approximate. Sawteeth on upper (tectonically higher) plate -  Volcanic and sedimentary rocks  2  Symbols Geologic contact (approximate)  Thrust fault Identity and existence certain, location inferred. Sawteeth on upper (tectonically higher) plate -  Normal fault Identity and existence certain, location accurate. Bar on downthrown block -  Normal fault Identity and existence questionable, location approximate. Bar on downthrown block -  Strike-slip fault, right-lateral offset. Identity and existence certain, location inferred. Arrows show relative movement Ductile shear zone or mylonite zone Porphyritic feldspar-hornblende dykes Roads Fossil Locality Limit of Geological Mapping Lineament io I  Figure 3.4: Geological legend to accompany figure 3.3, showing stratigraphic units, structural and topographical information.  64  /  — ;  Parallel bedded mudstones dominate topography  Figure 3.5: Photoplate of the Tchaikazan River Formation: sedimentary-dominated facies: A) Wellbedded, planar sandstones. B) Peperitic contact of mudstone and intrusive unit. C) Coarse poorlysorted sediments with rip-up clasts. D) Syn-sedimentary folding. E) Large-scale folding in Formation.  65  Plagioclase-phyric andesite ciasts  Bedded, resedimented volcaniclastic rocks  Resedimented volcaniclastic sandstone  Coherent andesite flow unit  Coherent vesicular andesite flow  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. 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 Formation from the Tchaikazan River area  Volcanic facies (Interpretation)  Coherent vs. Volcaniclastic  Plagioclase-phyric andesite  Lava flow  Coherent  Flow or shallow Monomict level intrusion  Vesicles or no vesicles. Brecciated Lava or intrusion flow tops. Chilled flow tops  Volcanic breccia  Flow dome  Volcaniclastic  Brecciated post- Monomict or eruption polymict  Variable breccia textures: sorting, angularity, phenocryst content  Volcanic breccia (primary) Lava flow top  Volcaniclastic  Autobrecciated andesite (primary)  Monomict  Moderately sorted. Blocky, angular Volcanogenic andesite clasts. Within andesite matrix commonly  Poorly sorted volcanic breccia Lahar deposit  Debris avalanche from flow dome  Volcaniclastic  Syn-volcanic  Polymictic  Poorly sorted. Non-stratified. Massive-graded or diffusely bedded. Thickness: <lmto >lOOm. Unconsolidated, nonwelded  Volcaniclastic sandstone  Sub-aerially reworked: Rivers, alluvial fans  Volcaniclastic  Epiclastic  Polymictic  Textures common in surface Sedimentary sedimentary environments. Matrix supported. Bedding surfaces common  -  Facies  Mono-polymict Main structures observed  Interpreted class of fragmentation  Volcangenic  Volcanogenic sedimentary  Red andesitic breccia. 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.  Fractured andesite flow top breccia. Competent moderately phyric andesite flow. Competent andesite, minor fracturecoating 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. 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  Porphyritic diorite Quartz monzanite Diorite dyke Porphyritic hornblende-phyric dyke Extent of geological trench cutting  •  Position of diamond drillhole een  I  08TSK-\ O8TSK-02 O8TSK-03  -Ø  I)  :-1:\ Feldsparhorn blende yry dyke  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. -  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  No vertical exaggeration SE  !  Drill core Porphyritic Hub diorite Hydrothermal breccia Andesite  J  Inferred geology  LZI  Porphyritic Hub diorite Hydrothermal breccia biotite magnetite alteration -  +  Andesite (Powell Creek)  Porphyritic feldspar-hornblende dyke  Feldspar-hornblende dyke  Overburden  Underlying pluton  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.  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  Facing west 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.  73  Intense sericite alteration of feldspar phenocrysts  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 hornblende 14 (top left). F) Same as in E in crossed polars, showing intense sericite alteration of the matrix.  Tagliatelle thrust  Linguine thrust  North  —  — — —  U)  —  a) a) E  —  —  /  +  —  rut  A  //  )÷  —  /v /  z  —  Z /  —  Underlying diorite pluton  No verticsl essggerstion  2800 2700 2600 2500 2400 2300 2200 2100 2000 1900 1800 1700  B  449356 mE, 5668844mN  449896 mE, 567489 mN  Southeast  2800 2700 2600 2500  t_-  2400 U)  a)  a)  E  Northwest  800 700 600 2500  I_2400  2300 2200 2100 2000 1900 1800 1700 1600 1500 1400  2300 I_2200 2100 2000 1900 1800 1700 1600 1500 1400  C  No verticsl exsggerstion  14 453676 mE, 5669825 mN  D N 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.  Observed outcrop of the Tchaikazan Rapids pluton  j  N Magnetic low  Syenite and diorite in outcrop  /  I  L.  ThN*  j.  •_7  (  \  //  Northwest Copper pluton in outcrop  )  // )  I \\ \ ‘>  __  c— ,s  —c  Coherent andesite of the Powell Creek Formation  -  1(  ) /  1:  //2  \  ( //  /  / Coherent andesite observed in outcrop  Subsurface  /  Northwest Copper plutol  /  }  “  -  —h  ‘j-1  h 9 anefthI ‘  I —  -‘  ‘I__I /l_J .\  v-  -‘  -‘  -  Magnetic high associated with Powell Creek Formation  ‘.  1  subsurface Hu,M,trusIy compiexj  .J ....  -  1  -  Jz  1  Key to magnetic data:  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).  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  D  N  N  C  N  E 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. -  00  Table 3.2 Summary of Geochronology samples and rationale for sampling from the Tchaikazan River area -  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, 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 or Northwest Copper intrusive centres.  U-Pb  80.85 ± 0.87  O6LH-GO1  453136  5669870  Charlie  Feldspar-hornblende dyke  Determine whether this magmatism is related to the Hub or Northwest Copper intrusive centres.  Ar-Ar  77.5 ± 0.97  O6LH-G02  4553353  5669938  Charlie  Feldspar-hornblende dyke  Determine whether this magmatism is related to the Hub or Northwest Copper intrusive centres.  U-Pb  76.6 ± 0.7  Northwest Copper Northwest Copper Northwest Copper  Equigranular Diorite  Determine the age of the Northwest Copper pluton; is it related to the Hub intrusive centre? Determine the age of dyke; is it related to the Northwest Copper pluton? To date the andesite from this outcrop  U-Pb  57.3 ± 0.85  Ar-Ar  60.0 ± 0.46  Ar-Ar  22.2 ± 0.70  U-Pb  81.2 ± 0.78  Northwest Copper pluton O7LH-238  447595  5670561  O7LH-231  447561  5670167  O6LH-039-1  00  Porphyritic diorite Andesite  140  A  B  O6LH-HUB-36 Hub diorite Ar (biotite) 9 Ar/° 40 = 80.53±0.42 Ma (2cy) -  too  Hub diorite r (biotite) 40 A 9 Ar/° 79.56 ± 0.42 Ma (2a)  120  100  80  65*  60  40  56.53*0.42  - 78565042 (PI*t***. e 9  (2Riinorof.5%)  I MOWO I  (2  1.88060546*65.12  btLde, 88.4% 0088*  ftxJ  20  .  nd*ding J.rror 08.5%)  MSV40  0.64. p*obObity40.72 787% 01 the  40 40  20  40  40  20  100  C  60  80  100  O7LH-231-1 -Diorite dyke from Northwest Copper = 60.01 ± 0.46 Ma (2cr)  O6LH-HUB-45 Feldspar Horn blende dyke 69.6 ± 1.1 Ma (2a) -  100  46  Cumulative 39 Ar Percent  Ar Percent 39 -Gum ulative  80  60  (0 . 00806*9 0000 08.8%) MOWS. 1.07. p,06e011180.38  20  0  20  40  88  40  40  f’PIotoooese. 60.01*0.46 Mc 22, in*Iod(r,g J-errOr 08.5%) MSWtI 0.93. p7600b46y*0 46  800  Cumulative Ar Percent  0  20  40  60  80  100  Cumulative Ar Percent  E  Feldspar porphyry dyke = 77.49 ± 0.97 Ma (2(3)  Charlie dyke Gol  20  0  20  40  60  80  100  Ar Percent 39 -Cumulative  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 O7LH231-1, Sample06LH-GO1. F)SampleO6LH-039-1.  82  A  B,  Charlie dyke (south)  ci  0)  O6LH-G02  O6LH-GO1  cj  Hub diorite  Feldspar-hornblende porphyry dyke  D  94  86  G) 0) <78  O6LH-HUB-45  O7LH-009  E  Northwest Copper Pluton  1) 0)  O7LH-238  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.  83  • U-Pb age Zircon: Hub porphyry D U-Pb age Zircon: Northwest Copper • Ar-Ar age Biotite: Hub porphyry Ar-Ar age Hornblende: Hub porphyry D Ar-Ar age Hornblende: Northwest Copper -  -  Hub diorite  -  •  O7LH-HUB-38 Hub diorite O7LH-HUB-36  -  -  O7LH-HUB-45 North Charliedyke I O7LH-GO1  Northwest Copper diorite dyke O7LH-231 -1  Andesite dyke O6LH-039-1  5-0—H Northwest Copper pluton O7LH-238 South Charlie dyke O7LH-G02 I I  I  I  North Charlie dyke O7LH-GO1  Hub intrusive  suite  Hub diorite O7LH-009  100  I 80  I 60  I  40  I 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 (m) Guess) 07-SB-GEO-O1  891-01  497161  5663935  1850  TC  U-Pb ArlAr (zircon) (Ma) (Biotite) (Ma)  Within error?  AFT (Ma)  ZFT (Ma)  AFT (Ma)  AFT 2a  ZFT (Ma) ZFT 2  Fine-grained quartz mnnzndiorite  Grizzly Cabin pluton  100  y  49.4 ± 5.5  88±4.9  49.4  11  88.0  9.8  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  EMP  Equigranuiar granodiorite  Mount McLeod granodiurite  83.2 ± 2.6  y  40.8 ± 2.4  94.7 ± 4.8  40.8  4.8  94.7  9.6  45.0 ± 6.2  45.6 ± 2.3  45.0  12.4  45.6  4.6  55.6 ± 3.3  94.7 ± 4.6  55.6  6.6  94.7  9.2  nol requested  71.4* ± 3.5  0  71.4  7.0  31.4 ± 1.8  76.6 ± 4.7  3.6  76.6  9.4  ZIte closure  180  ZFT closure AFT closure geothermal gradient (CIkm)  220 110 30  1850 07-SB-GEO-02  891-02  471890  5661590  07-SB-.GEO-04  891-03  473567  5660789  1850 1420 1420 2120 2120  07-SB-GEO-05  07-SB-GEO-12  891-04  891-05  476935  473633  5662480  2120 2100  TW  Altered equigranular granite  Battlement ridge granite  5658101  2100 2100 2550  EMP  Coarse grained biotite granite  Mount McLeod granodiorite  86.0 ± 1.3  y  2550 2550 06-SB-GEO-2  07-LH-GEO-03  891-07  891-06  450078  453432  5675682  2250  NWC  Fine plagioclase hornblende porphyry  Tchaikazan Rapids pluton 89.3 ± 1.4  5668870  2250 2250 1575  HUB  Purphyritic diorite/granodlurite  Hub diorite intrusion  81.19 ± 0.78 79.56 ± 0.42  y  31.4  1575 1575 TC Twin Creeks; EMP Empress; TW- Taylor Windfall; NWC Northwest Copper; HUB The Hub -  -  -  -  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  20.0  0.0  40.0  I  60.0  I  I  80.0  I  100.0  120.0  Age (Ma)  Key to samples •  Mt McLeod granodiorite  o  Mt McLeod granodiorite  •  Mt McLeod granite  Figure 3.23:  2 a error -  • * *  Tchaikazan Rapids pluton  Thermochronometer  0  Hub diorite Grizzly Cabin pluton  -  -  0  -  ZFT U/Pb AFT  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. (2008).  Additional sample data from Blevings  86  Thermoch ronometer 0  -AFT  4000 3500 /  3000  , , ,  2500 E /  rrir,  .  W  /‘ Key to sample location  0 Empress (O7SB-GEO-02)  1500 1000  • The Hub diorite (07-LH-GEO-03) • Grizzly Cabin (07-SB-GEO-01) • Mt McLeod Gre (07-SB-GEO-12)  / -  500  • 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  Intrusion of Hub diorite -80 Ma  Intrusion of Northwest Copper pluton 60 Ma  Present day 30 Ma  1 km 2 km 3 km -c 0.  Present depth of Hub porphyry  Diorite dyke at 60.01 ± 0.46 Ma (Ar/Ar horn blende)  4km AFT (110°C) 5 km 6 km 7 km Northwest Copper pluton 8 km  Intrusion at 57.33 ± 0.85 Ma (U/Pb zircon)  Hub diorite intrusion  \  Present erosion level  Depth of closure temperature  Figure 3.25: Schematic diagram illustrating the emplacement and exhumation history of the Tchaikazan River area. Data compiled from AFTIZFT analysis.  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 m , 3 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. occurred  during  Cretaceous  contractional  deformation,  as  It may in part have  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.  A A A A AA ‘A AA  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.  I  Early Cretaceous 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.  Mid-Cretaceous  I  Sinistral movement is active until at least 89 Ma.  IA  IA A  Mid-Cretaceous contractional ‘crunch’ is exhibited by the NE-directed Waddington thrust belt and the SW verging Coast Belt thrust system.  A A  • Study area  A A  East Waddington belt (EWB) and Gambier Group. Intermontane superterrane Methow-Tyaughton basin Insular superterrane Bridge River Accretionary complex  Figure 4.1: Tectonic evolution for the South east Coast Belt (SECB) and the Tchaikazan River area. Modified from Israel et al. (2006). 94  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.  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.  u  /  Figure 4.2: Reconstruction of the volcano-sedimentary system within theTchaikazan River Formation, including major facies associations and tectonic setting (modified from Israel, 2001).  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 Stratigraphic sequence prior to initiation of thrusting  Pc Try Trt  Trs  -  -  -  -  Regional contraction Thrust development Stage 2 -  -  Powell Creek Formation  Lower detachment  Tchaikazan River Formation volcanic -  Tchaikazan River Formation volcano-sedimentary -  Tchaikazan River Formation sedimentary -  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.  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 volcanosedimentary 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 largescale 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  ±  ±  biotite alteration ranges from intense biotite-only alteration, to  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. chlorite  ±  Strong  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 2 A (Ca ( O 3 ) AlSi io(OH) I 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 f0 , and aluminous rich environment (Khashgerel et al., 2 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). obliterated.  Primary textures are commonly  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 alteration.  ±  magnetite  ±  quartz  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 veins cross-cut the Hub diorite and hydrothermal breccia.  ±  sulphide  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 H S or HS 2 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). porphyry deposit exhibits this trait.  The Hub  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 veintypes 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 Quartz-magnetite  ±  ±  chalcopyrite veins and cross-cut the hydrothermal breccia.  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  ±  pyrite veinlets. Pyrite  ±  chalcopyrite veinlets cross-cut and therefore post-date quartz-magnetite ± ±  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 CharlieNorthwest Copper area (Figure 5.17). The aim of these studies was to approximate pressuretemperature-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 H 0 and NaCI. They are typically sub-rounded and vary in size from 52 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 ‘ C (98.9%), with the rest mainly consisting of ‘ 2 C 3 (Browniow, 1996). Carbon in hydrothermal fluids can be present in a number of forms, but occurs primarily as CO 2 or CH . There are large isotopic fractionations between reduced and 4 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 C0 , 3 2 C0 HC0 2 H , , 3 and C03 . 2  Carbon may be derived from a magmatic source, oxidation of reduced carbon  reservoirs, or by leaching of sedimentary carbonates. The distinctive 6’ C values of each of these 3 sources, aids the determination of the CO 2 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 & C values in the mantle range (-2 to -8%o) (Rollinson, 1993). 3 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: ‘0 (0.0375%); and 180  160  (99.763%);  (0.1995%) (Hoefs, 2004). Oxygen isotopic composition, expressed as  is a measure of the ratio of  180  (0.1995% natural abundance) to  sample as it deviates away from the oxygen isotope standard (VSMOW  —  160  (99.763%) in the  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’ C isotopes. 3  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’ C and 6180 values 3 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  61 3 C  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  0H20 8 6’  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 oreforming stage at the Hub porphyry. Unfortunately the samples yielded a fractionation factor that was  too  low  to  geothermometry.  generate  a  feasible  temperature  for  quartz-magnetite  However, these veins are spatially related to biotite  ±  fractionation  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).  samples yielded values of 3.7%o and 4.7%o. equivalent fluid values for magnetite.  These  A temperature of 500°C was used to calculate  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’ C and 3 fluid values range from -1.2  8180  to -9.5%o, and  values are shown in Table 5.5. Calculated Ô’ C 3 8180  fluid values range from +6.5 to +l2.2%o.  Fractionation corrections for equivalent 6180 and 6’ 0 isotopic values at 300°C were calculated 2 H 3 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  C value. These anomalous values may be explained by contamination from 3 displays a higher ö’ 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 CO 2 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  6180  range from 7.1 to l5.5%o, with an average of 11.1%o. Complete data for  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 (VSMOW) (Table 5.4).  6180  rock value of 6.6%o (VSMOW), and a 6D rock value of -113%o  The corrected  0H20 8 6’  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). 500°C quartz veins from the Hub display  0H20 8 &  At  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 8 have  been  involved  in  their  formation  (Figure  5.18).  Samples of calcite veins were analyzed using 6’ 0H20 and 613C 8 02 values (Figure 5.19B).  6180  and 8’ C calcite trends from the Tchaikazan River area are mostly consistent with precipitation 3 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 0 18 values of —1 O%o. Calculated Oiuo ö 18 values from Northwest Copper ö 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 >1 2 %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  Legend to hydrothermal alteration mineral assemblages (ca) alteration Epidote Pervasive and vein-hosted Propylitic alteration (index 1 2) chlorite, calcite, albite, ± epidote Propylitic alteration (index 3) Epidote veining, pervasive chlorite  Biotite ± magnetite alteration  E1 E1  Kaolinite-dickite-illite alteration  E1  —  Undifferentiated valley fill  —  Thrust fault  y — —  Silicification Unknown/or background regional metamorphic grade  Sericite alteration (phyllic) carbonate alteration  Quartz-diaspore alteration  y  Normal fault Strike-slip fault  —  o  Sense of movement 500  l000m  High density vening  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  Table 5.1: A summary of hydrothermal alteration and mineralization sequences for the Tchaikazan River study area, compiled from field and petrographic observations.  Least Altered Minerals  Early (High temperature) Bio-Mag (Kfdpr)  Qtz-mag  Hornblende  Bio, Chi  Bio  Biotite  Bio, Chl  Mag  Plagioclase  K-fdspr (rare)  chlo  Mag.  Abundant >40%  Suiphides  Dis Cpy, moly  Veins and veinlets  Qtz-mag, QtzCpy-moly  Primary rock texture  Preserved mostly  Abundant >80% Diss. Cpy, moly, py, minor bn Qtz-py, Qtz-Cpy py Destroyed and breccia  Transitional (Feldspar destructive) I Chi-EpiQtz-seri  Di-kao  Aib  Seri, Chio  4  Late (Feldspar destructive)  Chlo, Ep, Cal, Aib Chi, Sen  I I  Qtz-dia  Seri, Chlo Qtz-dia,  Pig, Sen  Chi, Sen  Ill, Kao, Dkt, Mnt.  Hem.  Mag  Hem.  Hem.  Pyr  Mainly Py, some Cpy  Pyr  Tetra.  Pyr  Epi, Cpy, Cal, Py  Rarely Py  Diss. Mai, azu  Destroyed mostly  Somewhat preserved  Destroyed  Destroyed, brecciated  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 feldspar-hornblende dyke, similar to phase to the southwest  Abundant secondary biotite, up to ‘-5% dissminated magnetite. Chalcopyrite, pyrite and magnetite in quartz veins and as small stringers  /90  Strong biotite-magnetite alteration: often accompanied by feldspar growth. Sporadic outcrop; brecciation common  47  45 I I I  01 18E  19  Ii II I  31  20  28 27  Pervasive feldspar destructive alteration sericite abundant chlorite after hornblende and up to 10% disseminated pyrite  4—  -  /  Intense magnetite alteration of Hub diorite, often accompanied by a brecciated texture  Secondary biotite dominant in primary mafic igneous mineral sites  Key to pervasive alteration Sericite-chlorite Chlorite-epidote Monzonite is not altered by magnetite biotite. Partial sericite, chlorite, epidote alteration only  Biotite-magnetite  -  2.5cm=50m  silicification 31  sample number i.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. -  54  zp  1—  12  14  Epidote observed  —.  B  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  I  ic RE = Rock Elour EP = Eine-granied porphyry QV = Quartz Vein  13 ----  = = = =  Quartz after plagioclase Clast margin Qt 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. .  -  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  • •1  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  2 4 cmO I_I  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.  128  Table 5.2- Summary of Vein Paragenesis, Alteration and Mineralization for the Hub porphyry deposit  Vein paragentic sequence  E a  Vein Name  Mineralogy  Quartz stringers  Quartz (minor chlorite)  Thin (<3 mm), abundant. Fragments of these veins are observed in the hydrothermal breccia.  Quartz, Ca plagioclase, magnetite  Quartz  Fine-grained magnetic  Straight-edged, combtooth quartz and magnelite in centre of vein  Sulfide, chlorite (quartz and sericite)  Sulfide (chalcopyrite, pyrite, rare molybdenite)  Thin (<5 mm), abundant, sulfides form commonly in centm of veiniet, often have chlorite or sericite halo (<3mm)  Molybdenite stringers  Dominantly molybdenite (a pyrite)  Thin (<1mm thick), stringers of molybdenite. Fracturecoating texture on fresh surfaces,  Quartz  Quartz chalcopyrite bomite  Thick (up 1040 mm) straight-edged veins. Chlorite ± muscovite selvages from 2 mm to 10mm into host rock.  1-  Sulfide  +  -  Quartz white mica Quartz pyrite  -  muscovite, (a chalcopynte), and rare Massive-textured, interlocking quartz and muscovite crystals.  Associated intrusions, alteration, suiphides  Closest vein description from Cannell et al., 2005 and Gustafson and Hunt, 1975.  C rosscu U’ing relationships  -  C  Hub Dionte  Crosscut and offset by sub-vertical magnetic (altered to chlorite) veinlets  -  -  R  Hub Diorite  Associated with biotte magneite atteratioCrosscstn Hub diorite Ia veins from Cannell at at., and are found 2005 truncated in clasto of the hydrothermal breccia  Magmatic  C  R  C  Hub Diorite  Form the centre to re—opened veins? Crosscut by quartz Chalcopyrite, pyrite and rare molybdenite. sulphide veins Vein selvages absent.  2 chlorite veins  Magmatic  -  C  C  Hub Diortte  Intense, coarse-grained sencite haloes extending up to 5 mm into host diorite.  Crosscut Hub Diorite  C  Hub Diorite  Associated with potassic alteration. Sulphides are chalcopyrite, pyrite, rare bornite.  Crosscut Sulfide, chlorite (quartz and sericite veins  2a/2e veins from Cannell ci at., 2005; B veins from Gustafson & Hunt, 1975)  Magmatic  C  -  Crosscuts the Hub diorite and is often brecciated  Earliest vein type at the Hub porphyry  -  +  -  -  R  Hub Diurite  Unknown  Gypsum (after anhydrite), molybdenite, chalcrThick (10-60mm), straight-edged; sulfide seam (molybdenite)  R  C  R  Hub Diorite  Phyllic haloes (sericite); suiphides are chalcopyrite, pyrite and molybdenite and tend to be coarne-grained and parallel to vein walls  Cronscuts the Hub diorita  3 veins (PH) stage from Cannell et al., 2005; D-veins (Gustafson & Hunt, 1975).  Carbonate  Carbonate (some gangue and sulphide)  R  R  C  Hub Diorite  Phyllic babes; feldspar destructive.  Crosscut all 1,2,3 veins.  4c veins  Accompanied by hydrothermal biotite and Abundant Ihorughout N/A magnetite. Pyrite is typically accompanied main diorile phase by chlorite development and in hydrothermal breccia  -  L  -  Sericite and chlorite babes up to 1 mm thick -  tage ( ann et aL, 2005)  -  Gypsum sulfide  -  e  Abundance Cu Mo VA  Features  Hydrothermal  Magmatic Hydrothermal Main Mo-rich fluid)  Mineralization Disseminated sulphides  Fine-graised disseminated chalcopyrite, Bomita and guiana are rarely observed. Chalcopynte mulybdenite, bomite, pyrite and trace galena readily developed in the hydrothermal breccia. Pyrite and chalcopyrite am closely associated,  Hydrothermal breccia and rarer in Hub diorite  Disseminated pyrite  Coarse grained pyrite  Range from 5-10 % disseminated pyrite in sericitealtered porphyry dyke  Hub diorile; Dominantly developed in the feldsparFeldsparporphyry dyke. porphyry dyke  Crosuculs the Hub diorite and hydrothermal breccia.  N/A  Late Magmabc  Coarse-grained chalcopyrite, pyrite  Sulphides grains occur in void spaces in breccia  Hydrothermal brenda  Post-intrusion and brecdiution  N/A  Late hydrothermal  Disseminated void filling 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  Associated with potassic alteration, hydrothermal breccia  Chlorite  Th E  ,Mássive calcite  Epidte  C) It)  c’.J  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. 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 150kV 6.0 2612x  Del WD 066 10.1  I  I  20 pin  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  Conibtooth quartz sulphide  Quartz, chalcopyrite pyrite galena -  -  Native Copper disseminated native copper  +  Quartz-carbonate copper  +  Abundance 1 Cu Mo VA  Associated intrusions, alteration, sulphides and rock types  Thick (up to 4 cm), combtooth-texturect vein, with centre-fill of sulphide.  C  C  Observed dominantly Tctraikazan River Formation: volcanic fades.  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  R  Malachite and chyrsocolla used as vector towards these veins. Observed in the Powell Creek Formation only.  C  R  Preferentially developed in the resedimented facies of the Powell Creek Formation. Intense epidote alteration of plagioclase in andesite host rocks.  R  Oxidation developed on surfaces. Diaspora alteration developed around brecciated, mineralized (tetrahedrite) quartz vein.  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.  Features  Mineralogy  -  native  Chalcocite  Chalcocite + malachite, chrysocolla  Thin (3- 15mm thick), often associated with quartz stringers. Secondary copper carbonate minerals. Black, metallic lustre to chalcocite  Quartzdiaspora 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.  Epidote chalcopynte magnetite (rare garnet)  Massive epidote, chalcopyrite, and magnetite, rare pyrite and garnet. Magnetite forms thin (up to 7 mm thick) stringers.  Combtooth quartz and calcite centre  Quartz and Calcite  Combtooth quartz with centre-fill of calcite,  Massive carbonate  Calcite only  Massive calcite (2-100mm) thick veins, Randomly oriented. Typically planar.  -  Epidote clialcopyrite magnetite  -  -  -  -  -  Quartz Quartz and calcite carbonate Massive Quartz Quartz -only  Quartz crystals intergrown with fine-grained calcite. Multiple generations of quartz. Milky quartz in planar-sided veins (10-70mm thick).  Combtooth Quartz  Quartz (± suTpflides)  Combtooth quartz, growing to centre of vein. Sharp, planar margins. Suiphides (chalcopyrite. pyrite and rare galena) form in these veins.  Epidote only veins  Massive, fine-grained epidote  Epidote only. Veins range from (20- 100 mm thickness).  Calcite veins  Massive calcite  Massive calcite. Veins range in thickness from mm up to 50mm. Typically planar vein margins.  -  -  Orientation  -  C  -  -  -  -  -  -  Shallowly dipping (25’ to EINE)  R  R  -  R 79/135, 13/335.  -  Shallowly (1638’) to NW  R  R -  R  -  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  -  =  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  Chlorite haloes to veins, chlorite replacing plagioclase and homblende in andesite. Devteoped in Tchaikazan River Formation and Powell Creek Formation. Epidote selvages up to 10mm in andesite host (07-170).  C  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  Chlorite, epidote, calcite alteration extending up to 20 mm into host andesite is common  common, R  =  rare,  -  =  absent  B -  Hemame’  I  k  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. -  135  Figure 5. 15: Photoplate showing the styles of hypogene and secondary mineralization in the CharlieNorthwest 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  A Vein Mineralogy  Stage  Early Mineralization  I  Mag  II  Qtz-Mag±Cpy  III  Qtz Mag ± Cpy ± Py Qtz ± Mo ± Cpy ±Py Qtz-Py-Cpy Py±Cpy Anh veinlets Qz±Anh+Py+Ser Qtz sulfide poor  -  V VI VII VIII  Vilil  Late Mineralization  Bio (Cl) —. —  -  IV  Main Mineralization  — — — —  -  Mag: Magnetite, Bio: Biotite,  Qtz:  Quartz, Cpy: Chalcopyilte, Py: Pyrite, Anh: Anhydrite, and Ser: Sericite.  B Stage  Qtz:  Vein Mineralogy  I  Qz-Cpy-Py±Ga  II  Qz-±Py  III  Qtz-Dia-Tet  IV  Qtz-Ca-NatCu  V  Qtz-Ca-Chal  Early Mineralization  Main Mineralization .  Late Mineralization  . —— —  ‘ .‘  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) CharlieNorthwest 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 .,inera.I separate kaolinite quartz quartz quartz magnetite magnetite quartz quartz quartz quartz epidote quartz quartz quartz quartz quartz epidote quartz quartz quartz quartz quartz magnetite quartz quartz  l8-  iur  Sample no. O6LH-1 12 O6LH-058-4 O7LH-1 00-4 O7LH-230 O7LH-230 O6LH-HUB-09m O7LH-HUB O7LH-132-2 O7LH-225 O6LH-HUB-38 O7LH-059-2 O6LH-082A O6LH-43A O7LH-102 O7LH-019-2 OO7LH-CHUCK O7LH-230E O7LH-NWCublade O7LH-231 O7LH-049-3 O7LH-142 O7LH-228-2 O7LH-HUBm O7LH-HUBq O7LH-040 Sample no. O6LH-112  Mineral separate Kaolinite  Vein or rock description Kaolinite-dickite (advanced argillic) Massive Quartz with pyrite, cpy Crustiform quartz vein from Hub w/pyrite Massive Quartz vein w/ garnet and epidote Massive Quartz vein w/ garnet and epidote Massive magnetite Quartz vein with pyr, cpy and mol Massive quartz with chalcocite Quartz Quartz vein + magnetite Epidote Quartz from quartz-diaspore alteration Massive quartz vein with py, cpy and gal Quartz vein Quartz vein Crustiform quartz vein w/ pyrite Massive Quartz vein w/ garnet and epidote Quartz from possible bladed quartz vein Quartz vein proximal to NW Cu pluton Massive quartz with minor late calacite Quartz from within quartz-carbonate vein Quartz vein in intense epidote-andesite Magnetite from quartz-magnetite vein Quartz from quartz-magnetite vein Dogtooth quartz-sulfide vein Host Rock Kaolinite-dickite (advanced argillic)  0 Wt/ 2 H 0  14.5 13.6 15.8 16.3 9.3 10.2 16.3 14.6 14.7 16.3 13.8 15.3 17.2 16.5 15.2 17.2 13.6 13.2 16.7 15.4 13.2 14.5 10.6 16.0 15.4  oI  100  (VSMOW) 11.7 11.9 10.3 14.3 3.4 3.7 9.5 8.6 8.2 8.7 7.5 14.5 12.2 9.5 9.2 11.9 7.2 9.0 14.8 15.5 9.4 9.6 4.7 9.2 12.2  3D(VSMO W) 6.6 -113  0 WthH O 2  139  High temperature ‘-500°C granitoid andesite magmatic water  meteoric water  metamorphic water Cl) 0  E U)  0  2  Legend to quartz veins Northwest Copper  TheHub 4567 89101112 8180 (%o)VSMOW  ‘13  14  Moderate temperature —350°C granitoid andesite magmatic water  meteoric water  metamorphic water ..  3  Legend to quartz veins Shift in isotopic values with decreasing temperature  °  2  Northwest 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. O 18 fractionation ö 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 0 18 values into the dominantly ö meteoricfield.  140  4 3  Unaltered limestone  2  Cretaceous seawater  0 —1 0 0  •  -2 • O7LH-044  Magmatic water  / OiL 213  C.)  07LH089  •  cc  -6  O7LH-071  Meteoric water  -7 -8  • O7U-f-O49-3  -9  •  -10  i  Legend to calcite vein  Charlie Northwest Copper  —11 -1  0  10  5 6180  15  20  (%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). 141  Table 5.5 Table of uncorrected Oxygen and Carbon stable isotope data for calcite veins in the Tchaikazan River area -  Sample no.  Vein-type  LHOO4-1 LH044-1  Calcite Calcite  LH089 LH 142 LH142 bI  Calcite Calcite Calcite  LH7 I LH77  Calcite Calcite  LH96-1 O7LH-21 3a  Calcite Calcite  -  O7LH-049-3c Calcite- quartz? O7LH-171c Calcite  Vein selvage 5mm chlorite Chlorite, minor sericite Little or none Minor chlorite Chllorite altered andesite Little or none Chlorite ± epidote  Host Rock Formation  Standard Deviation  dl3C% 0 (VPDB)  d180% 0 (VSMOW)  Tchaikazan River Formation Powell Creek Formation  0.056 0.044  -5.275 -5.301  12.004 12.074  Powell Creek Formation (non-massive) Coherent andesite Coherent andesite  0.088 0.047 0.145  -7.634 -11.931 -11.863  12.686 12.487 12.418  Tchaikazan River Formation volcanic Tchaikazan River Formation  0.080 0.050  -7.873 -7.678  11.932 12.279  hematite Powell Creek Formation (coherent) Pervasive chlorite Powell Creek Formation ± epidote  0.053 0.047  -7.950 -3.605  16.878 13.866  Chlorite Epidote  0.043 0.053  -6.865 -3.605  15.704 13.866  Powell Creek Formation? Powell Creek Formation (non-massive)  -r  490  Quartz-magnetite mineral pair  500 400 a)  LI  300  ci) ‘  /  ‘“  200  ci)  100 C  0  0 -100 -2  0  2  4  6  8  10  12  I2 1T(K) 6 0  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).  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 mineralization.  ±  magnetite hydrothermal alteration, and associated suiphide  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 flatlying 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 (JO 2 —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). anhydrite  ±  Quartz  ±  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 metalintroducing 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-, quartzwhite 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 2 (Meyer and Hemley, 1967). pH (Barnes and Czamanske, 1967) and higherjS Stable isotope magnetite  ±  6180  data (Chapter V) for formation temperature of 350°C for quartz  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 earlier biotite  ±  ±  albite. In the Hub diorite, chlorite-epidote alteration overprints  magnetite alteration, with shreddy chlorite after shreddy biotite.  alteration at the Hub porphyry deposit was probably contemporaneous with biotite  Propylitic ±  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 km ) magnetic 2 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, HC1SO ± HS-rich vapor from the underlying pluton and the disproportiontion of H 2 S can cause such 2 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., CO , OW, SO etc.) and determines which of the 2 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 isotope OH2o 18 values from quartz veins proximal to the ö pluton indicate a magmatic source for vein-forming fluids, likely exsolved from the Northwest Copper pluton. Stable isotope ‘ OH2o values indicate quartz veins with chlorite alteration 8 selvages formed from a mix of meteoric and magmatic fluids (Section 5.7). OH20 8 &  Stable isotope  and CH20 13 data indicate precipitation from magmatic fluids, which is in agreement with 6  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. production of high-temperature biotite  ±  Synchronous  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  Intrusion of Hub diorite —80 Ma >3km  +\ + +!  + + +  Andesite probably Powell Creek -  Hub diorite/granodiorite Hub hydrothermal breccia Feldspar-hornblende dyke  E] — —  —  —  • O  Quartz vein with Cu sulphide Quartz vein with biotite-magnetite Quartz white mica vein Sulphide stringer + chlorite + quartz Molybdenite stringer Anhydrite veins Carbonate veins Disseminated chalcopynte, bomite Disseminated Fe sulfide Pyrite Fluid flow path  -  -  Figure 6.1 Schematic diagram for the evolution of the Hub porphyry deposit. See chapter VI for detailed description of diagram. -  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  1.0  0.5 1 01 a, Q. U, 0  0  E  0  a0. I v.40  1 -0.5  I 0.83  -1.0 0  2  4  6  8  10  12  14  pH  Figure 6.3 Eh-pH diagram showing the stability fields of selected copper minerals at 25°C and I atmosphere (From Robb, 2005). -  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  Regional thrusting (Dl)  Intrusion of Hub diorite into powell Creek —80 Ma  —87-84 Ma  Intrusion of Northwest Copper pluton 6OMa  Present day Northwest Copper  Charlie  3OMa  1 km 2 km 3 km 4 km  AFT (1100 C)  5 km 6 km  Normal faulting  ‘  Northwest Copper pluton  Present erosion level “-‘  Cj  Hub diorite intrusion  Depth of closure temperature  Advanced argillic alteration —  Sulfide minerlization 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).  REFERENCES Ague, J.J., and Brimhall, G.H. 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(1997): Characteristics and controls of the largest porphyry copper-gold and epithermal gold deposits in the circum-Pacific region. Australian Journal ofEarth Sciences,44:3, pp. 373- 388. Sillitoe, R.H., and Perelló, J., (2005): Andean copper province: Tectonomagmatic settings, deposit types, metallogeny, exploration and discovery: ECONOMIC GEOLOGY 100TH ANNIVERSARY VOLUME, p. 845-890. Sillitoe, R.H., and Thomspon, J.F.H. (2006): Changes in mineral exploration practice: Consequences for discovery. Society of Economic Geologists Special Publication 12, pp. 193219. Sinclair, W.D. (2007): Porphyry Deposits, in Goodfellow, W.D., ed., Mineral Deposits of Canada: A synthesis of Major Deposit-Types, District Metallogeny, the Evolution of Geological Provinces, and Exploration Methods: Geological Association of Canada, Mineral Deposits Division, Special Publication No.5, p. 223-243. Skilling, LP., White, J.D.L., and McPhie, J. (2002): Peperite: a review of magma—sediment mingling. Journal of Volcanology and Geothermal Research, V.114, 1-2, PP. 1-17. Sláma, J., J., Koler, J., Condon, D.J. Crowley, J.L., Gerdes, A., Hanchar, J.M., Horstwood, M.S.A., Morris, G.A., Nasdala, N., Norberg, N., Schaltegger, U., Schoene, B., Tubrett, M.N. and Whitehouse, M.J., (2007): Pleovice zircon A new natural reference material for U—Pb and Hf isotopic microanalysis, Chemical Geology, v. 249, pp. 1-35. —  Smith, R.E. (1969): Zones of progressive regional burial metamorphism in part of the Tasman geosynclines, eastern Australia: Journal ofPetrology, v.10, pp. 144-163. Smith, R.E. (2005): The Ridgeway gold-copper deposit: A high-grade alkali porphyry deposit in the Lachian fold belt, New South Wales, Australia A discussion. Economic Geology, V.100, pp. 175-178. —  Spotila, J.A. (2005): Applications of Low-Temperature Thermochronology to Quantification of Recent Exhumation in Mountain Belts. Reviews in Mineralogy & Geochemistry, 58, pp. 449-466. Steiner, A., (1977): The Wairakei geothermal area, North Island, New Zealand; its subsurface geology and hydrothermal rock alteration: Wellington, New Zealand, New Zealand geological Survey, l33p. Thompson, A.J.B., Hauff, P.L. and Robataille, A.J. (1999): Alteration mapping in exploration application of short-wave infrared (SWIR) spectroscopy. Society of Economic Geologists Newsletter 38, pp. 16-27.  —  167  Tipper, H.W. (1963): Geology, Taseko Lakes, British Columbia (92-0). Map 29-1963. Geological Survey of Canada. Tipper, H.W. 1978. Taseko Lakes (920) Map Area, Geological Survey of Canada Open File 534. Ulrich, C.A., Gunther, D., Audetat, A., Ulrich, T., and Frischknecht, R. (1999): Metal fractionation between magmatic brine and vapor, determined by microanalysis of fluid inclusions. Geology, v. 27, 8, pp. 755-758. Ulrich, T, and Heinrich, C.A. (2001): Geology and Alteration Geochemistry of the Porphyry CuAu Deposit at Bajo de la Alumbrera, Argentina, Economic Geology, 96; 8, pp. 1719-1742. Umhoefer, P.J., and Schiarizza, P. (1996): Latest Cretaceous to Early Tertiary dextral strike-slip faulting onthe southeastern Yalakom fault system, southeastern Coast Belt, British Columbia. Geological Society of America Bulletin 108: 768-785. Umhoefer, P.J., Rusmore, M.E., and Woodsworth, G.J. (1994). Contrasting tectonostratigraphy and structure in the Coast Belt near Chilko Lake, British Columbia: Unrelated terranes or an arc backarc transect?. Canadian Journal ofEarth Sciences, 31: 1700-1713.  —  Wagner, G.A and van der Haute, P. Publishers, Dordrecht.  (1992):  Fission-Track Dating.  Kiuwer Academic  Waichel, B.L, de Lima, E.F., Sommer, C.A., and Lubachesky, R. (2007): Peperite formed by lava flows over sediments: An example from the central Paraná Continental Flood Basalts, Brazil. Journal ofvolcanology and geothermal research, V 159, p 343-354 Williams, T.J., Candela, P.A., and Piccoli, P.M. (1995): The partitioning of copper between silicate melts and two-phase aqueous fluids: An experimental investigaton at 1 kbar, 800°C, and 0.5 kbar, 850°C: Contributions to Mineralogy and Petrology, 121, pp. 388-399. Wilkinson, J.J. pp.229-272.  (2001):  Fluid inclusions in hydrothermal ore deposits.  Lithos, v. 55. 1-4.  Williams-Jones, A.E., and Heinrich, C.A. (2005): Vapor Transport of Metals and the Formation of Magmatic-Hydrothermal Ore Deposits. Economic Geology. Anniversary Special Paper 100, pp. 1313-1324. Wilson, A.J., Cooke, D.J., and Harper, B.J. (2003): The Ridgeway gold-copper deposit: A high grade alkali porphyry deposit in the Lachian fold belt, New South Wales, Australia: Economic Geology, v. 98, pp. 1637-1666. Yardley, B.W.D. (1993): An Introduction to Metamorphic Petrology, Longman Scientific and Technical, Longman Group, UK Zheng, Y.F. (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 CONSULTANTS LTD.  DRILL LOG  Project:  Taseko  Collar elevation:  Hole:  08TsK-01  Azimuth:  Proposed:  O8TSK-A  Dip:  Location:  453207 m East  Prospect:  Hub  Claim:  354057  Logged by:  L.Hollis  Drilled by:  No Limit  Assayed by:  ALS Chemex  Core size:  HQ  Dip tests by:  ReflexSS  5668942 m North  Length:  1594.0 m 320.0’ 6500 25.00 m  Date started:  Date completed:  2008/07/18  2008/07/19  Objective: To follow-up on prospective geochemical surveys and to try and intersect the northern margin of identified magnetic high.  SUMMARY LOG: 0.0 -4.6 m: 4.6 -25.0 m: 25.0 m:  CASING DIORITE: CL- & MS-altered; QZ veining; 0.5% CP, tr. BO, tr. MO, 0.5% PY EOH  170  Project: Taseko From  To  Hole Number: O8TSK-01  Rock-type & Description  From °  0.00  4.60_Casing  4o  qg  I  flinritA  and MS-altered. QZ veining throughout, most are up to 2 cm wide.  <@ 6.60 QZ Vein 10.00°> <1 6.90 CY Fault Gouge 80.00°>  /7— /7% // ‘//  2.00°c  7/ \// 7/—  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  ,,  I  Greyish-green, moderately competent diorite. Contains large, oscillatory.zoned PF phenocrysts. Mafic minerals are weakly altered to CL QZ veining with MS  /7%  selvages (Ito 20 mm In width).  /7— , //  @ 9.90 QZ-PY Vein 30.00°>  43  4°  To  Width  Sample  Mo  CU  Au  4  G0800501  1185_  G0800502  1150_ 45___ 0005  G0800503  SZS_ 2S.__ <Q.005  46___ Q.Q0f  \r  8.50  10.00  I50’”°°’°”  850  1ono  i.sn  415  115  <0.005  IflflA  11 50  1 50  252  in  ennnc  11.50  12.50  Inn  nnannsn7  .5AA  AA  enflnc  42.500  i45fl  Inn  i.5ueuuouo  ,uc  .5  en  10.501  .4ARn  un  ,05  2  en nnc  IAcfl  ICUn  Inn  anc  -  10.14 CY Fault Gouge 20.00°>  <@ 10.40 QZ-PY Vein 40.00°> <t 12.60 QZ.PY Vein 40.00°> e  4  I,—  ss  <  5  4.StL_ L5Q_ 9,SQ_ .SL. 7.0L. 1.50._ L00_ 8.SQ_ LSL.  I,— 7%  /7 \,9 I— //% // ..:t// /7—  <c 5.11 Fault 25.00°>  15.90_Diorite  5  o._  Grey-green, medium- to coarse-grained diorite. Core is moderately competent5 CL  9.90  0  ‘I  Alteration of BI phenocrysts Chlorite 3.00°ce Alteration of large PF  /7—  /7% /7 //  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  // \\//  //  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  16.60  16.60  1.00  G0800511  612  18  <0005  16.60  17.60  1_oo,,’°°,,S°.-°  321  17  <0005  17.60  18.60  1.00  192  2  <0.005  /7  stringers with mm-scale MS selvages. Small faults (less than 10 cm) lined with CYorMU. <@ 16.40 QZ-PY-CP-MO Vein 60.00° 10.00mm> —1  2008111103  Equity Exploration Consultants Ltd.  *graphic log notto scale  Page 1 of 2  Project: Taseko From  To  Hole Number: O8TSK-O1  I  Rock-type & Description  <@18.40 QZ-CP-PY Vein 60.000 10.00m> Pervasive green tinge to rock Chlorite 3.00°c  a  , a  From Sc  0  3  0  0.  0  41  40  5  0  To  Width  Sample  <<pm  ‘p°m  pi  4  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  of  /“!‘  I  1I0_  ILSL  tQQ_  130800514  19.5Q 20.Z0  2A.7Q  IJL.  G0800515  8__ -0.0D6 ‘114_ 2L_ c0.0ll6  ‘.t8Q_  tIQ_  G0800516  ‘.86  )I <<fl  ,, on  i  in  A5AAc17  9QA  9A9fl  lSA  tAkAfl51R  <tSI_  4__  <tOOL  7A  2  <A AAS  <11  5  A Af)5  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> <@ 19.30 QZ-PY-CP-BO Vein 26.00° 6.00mm>  20  -  I— I, I— 0  a  Alteration of matrix Chlorite 2.00°c  veins Pyrlte 0.50%s  a  veins Bornite 0.10%a  21.00  a  4’ii  P1° phenos Sericite 2.00°ca In QZ a On fractures in QZ  In QZ veins Chalcopynte 050°s a  In mm-size QZ veins Magnetite 0.10<A>m  25.00_Diorite  I  // i Greylsh.green, medium-grained diorite with P1° and HB phenocrysts. 02 veins wit // i/; strong MS selvages increase in width and MO content /1  <@ 21.40 QZ-PY Vein 30.00° 10.00mm> <@21.70 QZ-MO Vein 70.00° 30.00mm> <<Pervasive Chlorite 2.00°s  I,— //% II II  Selvages to 02 veins Sericite 2.00°c <<In 02 ‘0, if’ a In some 02 veins Chalcopyrtte 0.10°c ii f, ii— ° Along margins of 02 veins Molybdenite 0.50%s 0 lit? 9cnn 2 fin FAIl I a  veins & trace disseminated Pyrite 0.50%s  2008111103  Equity Exploration Consultants Ltd.  °graphiclognottoscale  Page  A  4 v  EQUITY I  CONSULTANTS LTD.  DRILL LOG  Project:  Taseko  Collar elevation:  Hole:  O8TSK-02  Azimuth:  320.0°  Proposed:  O8TSK-A  Dip:  -60.0°  Location:  453207 m East  Prospect:  Hub  Claim:  354057  Logged by:  L.Hollis  Drilled by:  No Limit  Assayed by:  ALS Chemex  Core size:  HQ/NQ  Dip tests by:  Reflex MS  5668942 m North  Length:  1594.0 m  304.20 m  Date started:  Date completed:  2008/07/19  2008/07/27  Objective: To follow-up on prospective geochemical surveys and to try and intersect the northern margin of the identified magnetic high; drilling at same location as drill hole O8TSK-01, but at a shallower dip.  SUMMARY LOG: 0.0 4.6 m: 4.6 57.7 m: 57.7- 60.4 m: 60.4- 65.8 m: 65.8- 86.70m: 86.7- 101.Om: 101.0- 224.Om: 224.0- 245.Om: 245.0- 304.2m: 304.2m: -  -  CASING DIORITE: MS-altered; QZ veining; 0.5% CP, PY, tr. MO BRECCIA: MG-Bl-CL-altered; QZ veining; 2% PY, 1% CP ANDESITE: MG-Bl-altered; 2% PY, 1% CP DIORITE: MS-altered; QZ veining; 2% PY, 1% CP ANDESITE: MG-Bl-altered; QZ veining; 0.1% PY, 0.5% CP DIORITE: MG-SI-altered; QZ veining; 0.3% PY, 0.3% CP, 0.01% MO BRECCIA: MG-Bl-altered; QZ veining; 0.5% CP, 1.5% PY, 0.05% MO ANDSITE: MG-Bl-altered, MS on fractures; QZ veining; 0.5% CP, 1.5% PY, 0.1%MO EOH  173  2  (I)  —4  01  o  p  —  (11  0  F’) 0) F’.) F’) 01  F’) .  F’) F’) 0  CD -  0) .  C) -  .  0  CD  0)  0  C.) F’)  C.) F’)  0  .  C.) F’)  0  CD  C.) F’)  0  CO  C.) F’.)  0  .  0  -J  C,) F’) F’) -‘.  C,)  0  0  C,) C.) F’) F’) CC.) 01 01  0  C.) F’) F’) F’)  0  -  C,) F’)  0  01  C.’) F’)  0  (31  C.) F’) p  p 0 0  C.) F’)  00000000000000  .  —  N  >  01 01 01 01 01 01 (31 (31 01 01 01 01 01 0) cDcD(D(0(o(o(ocCoDcD(Dp-. F’) CD -F’ 0) C,) F’) 01 CD 0) .F’. 0  00000000000000  () 0  CD  b  m  g  0  -‘ ØCD  0-I  CD  0’ CD — C,  0 C)  I I I  P  ox  n  -<  m  a  Project: Taseko From  To  0.00  6.00_Casing  Hole Number: O8TSK-02  /  Rock-type & Description  ‘, --  010  0  0  0  0  5  40  0  --  40  --  40  From  at  To  Width  Sample  —  0  Cu ppm  I  ppm  Au ppm  4  I ‘  4.60  I  23.80_Diorite  H H  II  Fine-grained, porphynitic diorite. The fine-gralned nature of the core is assumed to be an alteration effect. Core competency is poor. Weathered  5  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.  00  I,—  -  \  0  Pervasive (matrix & phenos) Chlorite 3.00°sss On fractures Sericite 3.00°c a ,  Molybdenite 0.10%s 10  50 9— // \//  <@ 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>  11  <c  17.60 green CY Fault 25.00°>  K”  487  <0.005  00800522  427  <0.005  G0800523  377  <0.005  00800524  566  <0.005  00800526  325  0.007  00800627  259  <0.005  00800528  457  <0.005  00800529  427  <0.005  00800530  443  0.005  G0800631  326  <0.006  G0800532  440  <0.005  G0800533  372  <0.005  00800534  268  00800535  245  9  0.008 <0.005  00800536  294  <0.005  I 4°  20  9 //°t /7°..”,,  >  f 9  <@ 23.60 QZ.PY-MG Vein 70.00° 3.00mm>  ‘1  I  I  5  /4”I  5  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 con 25 2008/11103  <0.005  00800521  I,  4,, 1/  <@21.40 QZ-MO Vein 70.00° 25.00mm>  39.00_Diorite  <0.005  \100°  <@19.80 QZ.PY.M0 Vein 30.00° 8.00mm>  23.80  393  9  <@ 18.00 green CY- MS? Fault 40.00° <@ 19.00 QZ-PY Vein 6.00° 3.00mm>  <@22.30 QZ-GY-PY Vein 60.00° 40.00mm> <@ 22.50 CY.MS Fault Gouge 40.00° 15.00mm  JL 050 3  <@ 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>  00  9  <@ 13.10 QZVein 70.00° 20.00mm> <@ 13.20 QZ Vein 20.00°> <@ 14.70 CY Fault 80.00°>  <  0  /1 ‘// 9—  843  00800520  00800525  .jj  Pyrite 0.50%a o Chalcopyrite 0.30%c  00800519  Equity Exploration Consultants Ltd.  H  5L 25.50 *graphic log notto scale  0  00800537  lii  0  00800538  116  5 6.50  1.00  IG0800539 o 29 j  1<0005 1<0.005 [<o.005  Page I of 11  I  Project: Taseko From  To  Hole Number: O8TSK-02  I  Rock-type & Description  axis, with another prominent set at 35-45 to core axis. Fracture-coating PY-MO.  From 0  0.50  50  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  1.00  I,—  G0800543  491._ 7L_ 0.905  II—  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  32.59_ 33.59 45 39 39.59_  Th5L  G0800648  414_ IL._ <Q.995 42L 9.00L 14 212_ Zt_ 9.9Q <000C 23 241 L 34 <95  37.5Q_  38.S0.  —  I—  <i 23.80 QZ Vein 30.00° 15.00mm>  4  Au  307  so 23.80- 27.50 Molybdenlte 0.02%s e 36.10- 37.20 Molybdenite 1.00%a a  <i 26.10 QZ Vein 60.00° 10.00mm>  0  Mo  475_ 4L_ <0.095  5,,  <@ 23.85 QZ.PY Vein 30.00° 8.00mm> <t 24.40 QZ-PY Vein 50.00° 7.00mm>  0  Cu  G0800542  /1  30  40  Sample G0800541  2.00 a 23.80- 27.50 Chalcopyrlte 0.1%a a 36.10- 39.00 Chalcopyrite 0.1%a Pyrite 0.30%a a Chalcopyrlte 0.30%  40  Width  27.89_ 29.89_ I.09_ 28.50_ 29.5L 1.99_  I—  Trace-minor CP in QZ veining as blebs. Areas of intense MS alteration between cross.cutting veins. Strong CL alteration of diorite.  40  To  ‘I  tOO  27  <0.005  4.50_ 1.P0_ G0800549 tSL 39.59 ILSL. tOO_ G0800552  473_ it_.  <J.095  G0800553  374_ 42_  <0&Q5  Q0 Q89Q55L 434 83  <95  I am  LQL_  <@ 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>  I— 33  —  I—  <c 29.55 QZ-MO.PY Vein 85.00° 55.00mm> <t 29.94 QZ-PY Vein 40.00° 15.00mm>  ,J.*  <@ 31.00 QZ-PY-CP Vein 30.00° 8.00mm> <@ 37.50 QZ (MS selvage) Vein 20.00° 2.00mm>  4  <@ 37.80 QZ-MO-PY Vein 30.00° 12.00mm> < 38.20 MS-MG clots, CL Fracture 60.00°  9OO........57.7O_Diorite  I—  I  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.  I, —  I— I—  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  I,—  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  ‘I  Molybdenite 0.10 <@ 39.10 MS-PY coating Fracture 80.00° 10.00mm> <@ 39.20 QZ.PY-CP.MG Vein 60.00° 7.00mm>  2008111103  —  Equity Exploration Consultants Ltd.  I  \9o 39.90_ 4Q.0Q  t09..  G0a00555  253_ L__  40.09_ 4t0L  t09_  G0800656  t09_  c30800557  328_._ 6___ <9.995 312_ 8.._ <0.90S  4t09_ 42.09...  42.09  Q.095  G0800558  510.  22..  0...009..  43.09_ 44.09_  tOO_  G0800559  2Z2.__ 8_____  9.908  44.09_ 45.09... 46.QQ_ 4Z.OQ_ 49.09_ 4.LOIL 49.90_  1QQ_ 1.90_ 1.90_ tOQ_ LOL 1.90 LOL. L09_ L0D  G0800560  338__.  L___  <9.9Q8  G0a00561  214___ 521___ °542_ 385_  5__.__ <Q.995 6_____ cO&Q8 2L_ <9.tIQS 29_ <it.995  43.09..  49.99_ 45.SL 41.00.. 4L00 49.99 49.09.. S0.OL 59.90_ 51.00.. St00 52.0 52.0L 5Q0*graphiclognottoscale  1.00 —  G0800562  r I G0800565  G0800566  55L_ 131_ 399_ 5 20 080055L 291 662 314 G0800567  <Q.995  <0.905 9.09L 0.007  Page 2ofll  Project: Taseko From  To  Hole Number:  Rock-type & Description  From 3  <  I,  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>  O8TSK-02  45  \  —  0  3  3  3  0  4  0  4  0  4  0•  0  —  Cu  Mo  Au  To  Wth  Sample  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  4  <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>  1/ I,—  <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>  ‘-4, II  <e 45.00 MS-Q2-EP Fracture 45.00°> I,—  <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°>  II—  50_  II  <( 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>  I,,  <@ 49.70 QZ -MO-PY Vein 75.00° 10.00mm> <@ 51.10 MG.HE Fracture 30.00°>  I,  <@ 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  I’’,  55  I,  4ti,  55.00 QZ (MS selvage) Vein 90.00° 5.OOmm2.....  2008111103  Equity Exploration Consultants Ltd.  *graphic log not to scale  Page 3 of 11  Project: Taseko From  Hole Number: O8TSK-02  /  Rock-type & Description  To  From  To  Width  Sample  Cu  Mo  0  0.  0  5  0  40  45  40  5  0,  Au  ppm  -  4  <@ 51.25 PY-CP Fracture 70.000> 3.00mm> 0 <i 51.65 QZ-PY Vein 20.00  57.70  60.40_Breccia  -  Hydrothermal(?)  I  I  Dark grey to black breccia. Moderately to strongly magnetic. Locally clasts of  L70_ 581L 100_  G0800574  77  SL_  8.70_ 61L40_  j7Q_  G0800575  ‘S  21___ 0.008  Sn *10  SI Afl  I  no  Ifl5flflS7S  ARC  9*1  n 005  SI *10  57  An  I flfl  tnsnne77  a,s  as  n floe  C2 An  I flfl  flnsnnc7a  goq  I0  en one  flnQnnc7a  2II  G0800581  594  8  0.006  5&40_ 65.OQ_ .5Q_  G0800582  SQL_  IL__ 0.005  88.QQ_ 6LtI0_ 100_ 4L00 6500 100_ Z.QP 6.00_ t00_  G0800583  tSZ__  30___ 0.00S  G0800584  0L_  14___ &1I5  58.00_ 69.tIO_ 100_  G0800586  243_  49_ D.005  59*00_ Z0.00_ Th00 Z2.QL  G08005s7  4I._  31_  G0800588  468_  28L_ 0.0Q5  0.005  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  I  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>  6580  8670  ‘It,  Large zoned PF phenocrysts. CL after BI and HB. Matrix has a strong green tinge  II  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.  II 10  —  ,  o Chalcopyrite 1.00%so Pyrite 2.00%s a With PY-CP Quartz Veining 3.00°oos  Chlorite 3.00’s  00  2008111103  23.00  I, II  <@ 66.50 QZ-PY Vein 20.00’ 5.00mm> <c 66.80 PY Fracture 25.00°>  —1  64.40  Dioritm  <@ 68.80 QZ-MO Vein 75.00’ 25.00mm> <c 68.85 MS-MO Fracture 70.00’>  An  65.40  1.00  Si—  Greenish-grey, medium- to coarse-grained diorite. Core competency Is good.  -  5  ‘II  75  —  Equity Exploration Consultants Ltd.  -I---  70.00_ Zt00_ Z2L 73.00_  I00_ 100_ 100 100_ Z40 100  G0800585  0.0Q5  006 25L_ W___ 0.0Q G08005i 3i9 4 G0800590  Z400.. Th..0L .1.0L  G0800592  309_  29_ 0.01l5  71.00_ 7SQL 100_ 75ll_ 77QQ_ jQQ_  G0800593  278_  2L_  G0800594  542  21_ Q.00L  Z8.00_ j0Q_ 00 Z9L I0Q  G0800595  501_  6I__ 0.SQL  ??.0L  *graphiclognottoscale  G30Q 311  6L  tLQQS  05  Page 4of 11  Project: Taseko From  To  Hole Number: O8TSK-02  Rock-type & Description  j 053  <@ 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>  0  4I,  <@ 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°>  40  —  //  0  4  0  4  0  4  From  To  Width  Sample  7onn  nnnn  inn  flnRnnKo7  iQQ 2.l_ Q_ 4,0Q_ 6.0Q..  82Q0 62gQ_ 14.QQ_ 85QQ_ 86.QQ_  S.0_  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 <  1mm wide.  PY-CP are the most common suiphides, locally disseminated In host rock. 90  —  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  pi efl  nnc  005  31S 2  t0_  G0800600  254__ 13_ Q.GQ5  tQQ_ tQS_ L00_  G0800601  2986_  G0800602  334__  G0800603  50L_  8LS_ tS_  G0800604  36__ 12___ <0.005  46___ Q06_ $._ Q006 3L_ Q.QOL  <@ 91.75 QZ-PY-CP Vein 20.00° 13.00mm> <@ 92.35 QZ-PY Vein 45.00° 5.00mm>  142_ <0.005 112i_ <0.OQS  9,00_ 180.00 1.QL i0Q.80 IGLOO LQL  130800618  216_ 0.05L 20&_ 0.QQ5_ 5j_ <0.0Q5 3L_ OOQL SL_ Q.QGL 3L_ 0..QQL 328_ 0.QQL 924_ 000L 82__ 0.QQL 862_ SL_ 0.OQL 755_ WL_ 0006_  130800619  61L....  iG1.S0 IGLOO Q.00_  130800620  58.0L <@ 90.30 QZ-PY-CP-MO (MO at margins) Vein 50.00° 20.00mm> <@ 91.20 CY-rich Fault Gouge 30.00° 10.00mm>  99.00.  tQ0._  130800617  74__ <0.006  95 — \-  <@ 92.30 HE-CY Fracture 60.00°> <@ 92.70 CY-nch Fault Gouge 40.00° 30.00mm>  \r°  <@ 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>  2008111/03  tQQ  i00 Q5P050L Z.QQ_ iQ0_ 130800606 51L_ LOD_ i00_ 130800607 S.QL 1.QL_ 130800608 84L_ 130800609 1150_ SQ.0L LQ0. 81.0Q_ t00_ 130800610 764__ 52.Q0_ tQL 130800611 66L_ 83.00_ 94.Q0_ i00_ 130800612 56L_ 4.0tt_ 96.Q0_ I.0L 130800613 475_ 85.QL 96.00_ 100__ .GQ500614_ 922_ 55.0L 97.00_ i,00._ 130800615 96L_ 57.0L 96.0Q_ tO0._ 130800616 105Q_  I  101.00_Andesite  169.10_Diorite  Om  ‘C  404  87,S0 85.0Q_ 80.00_ 90.00... 9t00_ 92.00_ 93.0Q_  Dark grey to black, altered andesite(?) with possible phenocrysts. Core  101.00  °pm  €2 —  /1  s  5  ‘1 85  alteration around veins. Mineralization is focused in veinlets  0.510  €2  <@ 80.20 QZ-PY (MS halo) Vein 85.00° 8.00mm> <i 81.40 QZ-CP-PY Vein 70.00° 15.00mm>  86.70  0  LSQ  <@ 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>  3  100_  I  Equity Exploration Consultants Ltd.  —  °graphiclognottoscale  Page  Project: Taseko From  To  Hole Number: O8TSK-02  j  Rock-type & Description  From 0.  0  5  0  Sample  Cu  Mo  Au  40  II  G0800621  554  43  0.006  phenocrysts. CL alteration of BI and HB phenocrysts. Several generations of QZ  II  102.00  103.00  100_  00800622  28L  15.  <0.000  103.00 104.00 404.00105.90  t00_  I,  tl0.  00800623 615_ 60900924. 5.05.  104.00  105.5.0  1.50_  G0500625  105.50  107.00  L50_  00800626  60L  37  0.OOL  t00  497  10  0.005.  t00_  60800527. 00800628  334  L Q.00L Z 0.005.  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  7/—  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  105.00105.00 109.05 110.00  /1  137.20- 142.60 Molybdenlte 0.05%aa 155.30- 155.90 Molybdenite 0.01 %aa 156..?.—  I  /7%  169.10 Molybdenite 0.02%uv 101.00- 105.50 Pyrite 1.00%ea 105.50- 169.10 Pyrite  <@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°>  <@105.50 CY-rich Fault Gouge 40.00° 40.00mm> <@109.05 QZ-CL Vein 45.00° 4.00mm>  34L_ 1L_ 0.055.  113.00  00800631  80L_  L__ 0.005.  440  32_ <0.009  /7  114.00  115.00  t00_  ‘.4L_  L__ Q.005 0  ‘I—  115.05 11.0Q 115.00 117.00  tO0. L0Q_  60900635. Z1 13 00 00800635 11L 4.. <5.05.5  II  IILOO  114.00  t00_  G0800636  52  2L 9.005.  114.05  115.05  tOO_  00800637  3Di  L_.  115.05  120.00  t00_  G0800638  16L  125.00 121.05  121.00  1.0Q_  00800639  122.00  tOL  00800640  57 caj  t 9.005. L 0.011. 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.  II  —  1/  /7  125  \ \cS°  /7  <@117.50 Qz-PY-MO Vein 40.00° 60.00mm>  “1  <@121.05 QZ Vein 80.00° 6.00mm>  //  ioo_  // —  K” //  Equity Exploration Consultants Ltd.  69L  55. 0.511  132.00 133.55  392.  1L_ 0.505.  795.  23.  00800650  343_ 5.__ 0.007.  t00_  G0800651  415_  t00_  G0800652  40L_  133.00 134.55 134.00 135.00  t50_  00800653  SSL  1.00_  G0800654  5.52_. L_ 5.012.  135.05  136.90  t00_  G0800655  135.00  137.00  t00_  00800656  594 864  137.00  131.05  I  <@127.30 QZ.CP Vein 85.00° 3.00mm> <@129.30 QZ-PY Vein 70.00° 8.00mm>  74_ 0.017.  00800647 G0800648  132.05  K” /7  G0800645 60000045. 7A5  129.50  129.00 130.5Q 130.00 131.50 \of  <@125.00 QZ PY.MO Vein 70.00° 60.00mm> <@126.40 OX-MS Vein 30.00° 5.00mm>  L00_  00800649  125.00  <@123.20 OX-MO Vein 60.00° 25.00mm> <@124.00 QZ-MO-PY-CP Vein 60.00° 50.00mm>  1° °graphic log not to scale  9.005.  t00 t00_ 1.0L t00_ t00_  125.00 126.L0 125.00127.00 127.05 125.06  of  <@116.20 PYVein 110.00° 1.00mm> <@117.10 Qz-PY-MS Vein 50.00° 40.00mm>  2008111103  34L_  G0800630  60000632. 00800633  <@113.70 QZ-PY Vein 65.00° 3.00mm>  <@131.30 OX-MG Vein 40.00° 3.00mm> .< @ 131.60 OX-MO Vein 70.00° 50.00mm>  00800629  t00  120  <@110.70 OX-MG Vein 20.00° 9.00mm> <@113.60 QZ-CL Vein 60.00° 3.00mm>  <@121.30 QZ-PY-MO Vein 60.00° 10.00mm>  t00_  t00_ t00_  <@109.90 Dominant orientation Fracture 50.00°>  <@114.30 QZ-PY-MO Vein 80.00°40.OOmm>  111.00  112.05114.00  II  <@106.20 QZ-PY-CL Vein 90.00° 35.00mm> <@107.00 QZ-CL (MS selvage) Vein 40.00° 20.00mm>  6L_ 0.005 l 0.005.  111.05 112.00  110.05 112.00  1/  0.01%a a 109.00- 110.39 Quartz Veining 2.00°ss a Quartz Veining 3.00°c  00 C  Mdth  Light grey-green diorite, core competency is moderate to poor. Large <10 mm PP veins cross-cut each other. Large (>10 mm) veins have MS alteration selvages,  4—  To  0.505.  4&_ Q.50L __  9.505.  15. 00L  138.00  t00_  00800667  8.SL  192 0.022. 52 0.025. 29 0.03  134.05 139.00  1.90_  41L  -31 0.005.  11000  100  G0800658 nRnnscq  14000  IRS  0007 Page 60th  Project: Taseko From  To  Hole Number: O8TSK-02  Rock-type & Description 0  50  0  0  0  0.  0  5  0  4  0  4  0  4  0  0  From  —  To  139.00  140.00  —  tMdth  Sample  1.00  00800660  Cu  Mo  Au  4  II  <@144.40 QZ-PY-CL Vein 20° 2.00mm> <@151.70 QZ-PY-CL Vein 65.00° 20.00mm>  I 140_  I /1 145_  14tQ tQQ_ i4 t0Q 142.00 143.Q L0L I4.9Q 144.Q t00_ j4399 j44Q 19Q_ j44.QQ j45.fl 1JQ_ I4S.0O 145.Q 1g  00800661 4j5_ 44_ O6QQ55 151 2Q4 00800653 495__ 7___ 00800664 323_ 1L_  14590  140.00  /7  14Z.Q L0L  i4LQ L00 i45.QQ 149.Q 1.9O i4 t  \ I  Q.O1L QQL  Q.QOL <Q0Q5  00800668 G0800666  195__  3___ 0..005  00800667  243_  00800658  ‘595_  7__ %Q05 22_ <0.005  Q50Q65L 54 G0800670 35i_  5 ‘1  L_ <Q.P5  isc  ThI L90  040Q57t 165 QS0O5ZZ IZL  151.60.  t52.Qf tOL  00800673  241__  39_  Q6QL  1  152.60.  151.9  L0L  00800674  410_  5___  Q.00L  II  151.60 154.00. L9L 154.60 155.00.  00800675  0Q_  I 150  \0°  I  155.QQ 155.90. 155_  7%  100_  155.00. 15L00. tQQ  \r  ISZ.00. 155.00.  100  j55.0Q 155.00. 1.0L  155.00. 160.00. tQL 16Q0Q 151.00. 1.0L 15L00 162.60. 1.00_ L0Q  I 160_  Ii  .142.60. 163.00. 1.00_ 143.00 144.00. 1.0Q_  II  9Q5  Q0L  G0800676  4___._ <.6.905 25 1.2__ 0.065  00800677  t33_  ‘t___._ <0.095  980Q5Z5. 153 17_ <0.005 00005l 181 <0.905 00800680 t6L_ 0 L___ <0.095 00800681 167__ ‘L__ <9.096 G0800682 IOL__ <0.096 __  00800683  ‘.30__ 04005 10L 00800685  15__ <9.096 18L <0.095  00800686  31._..  164.00. 1459k 1.00_  00800687  195.__  15__ <00Q5  165.0Q 164.00.  1.00_  00800688  ‘.24__  14_  164.00. 167.00.  t90_  00800689  111__  ISLQ0. 165.00. t00_  00800690  99_ t00  950086I 429  10__ <9.006 q %OOL c4 <9.096  149.00 170.00. 1.09.  00800692  107L  3___ <0.006 1.00 17i00 172.00. 1.0L  0860685.  Z4  <0.005  00800686  -145  t____ <0.095  is due to alteration, obscuring the original igneous texture. Core competency  172.00 173.00. t0ft_  00800695  t14_  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  173.00 174.00. 1.00_.  00800696 00800697  414_  15__ <9.Q95 5__ <9.096  177_  66_  165_  7%  r  /1 /1  169.10  197.00_Breccia Hydrothermal(? -  Dark-grey to black, medium- to fine-gralned breccia. The decrease in grain  2008111103  I si0170  \5’  —  Equity Exploration Consultants Ltd.  174.00 175.00. 1.0L *graphic log notto scale  __  <0.095 <9.0Q6  <9.005  Page 7of 11  Project: Taseko From  To  Hole Number: O8TSK-02  Rock-type & Description  From ° 5°  veins are also common. Dominant vein orientation is 70-80 to core axis.  0  3  0  0.50  0  Sample  5........ Q.Q05.  95QQ70t 48Z G0800702 392.... G0300703 323....  Si 0.000...  140.00. 191.00 lOlL.  G0800704  ‘Ijl_  5... 0.009..  190.00. 141.00 100....  G0800705  142..... 82  L......... 0.005 S 0.000. !L...... 0.005 IL..... Q.005 100  3.00°c  178.00. 179.00 1.00.... 179.Qft 190.00 100....  loo_  <@169.30 QZ-MO-PY-CP Vein 65.00° 80.00mm> <@169.50 Fault Gouge 15.00°>  141.40. 152.00 100....  G0800706 100.  .00400707  <@170.20 CY-rich Fault Gouge 85.00° 50.00mm> <@172.60 QZ-PY Vein 87.000>  143.00. 185_  <@176.70 QZ-PY Vein 85.00° 15.00mm> <@178.90 QZ-PY-MO Vein 80.00° 10.00mm>  <@191.60 QZVein 80.00°4.OOmm> 190_  —  50 mm  \cf  a 212.60- 214.00 Broken core with gouge material Fault Zone cc Quartz Veining  Pyrite  ‘Op  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> 2008111103  —  Equity Exploration Consultants Ltd.  191.00 100....  G0800715  404  199.00  lOlL..  G0800723  599....  24  <0.005  0.000.  9__ %005  L Q.0Q5 I 0.000. 5....... 0.009.. L......... 0.008.  19.... 0.OQS 29........ 0.005..  14 4L_ Q.0QL I.4......... 0.005..  64........ Q.OO9. 4L 9.405.  L......... 0.009.  1  0.009.  1........... 0.006.  G0800724 q1s.... 5___ 0.01_ 1.O0 1.00.... G0800725 1.00.... G0800726 869.... 7...... Q.00Z 100 080OZ2L 795 19 0.00L 202.00. 203.00 1.00... G0300728 605.. 4........... 0.006. 6............ <0.005 203.00. 204.00 1.00.... G0800729 462 204.00. 205.00 1.00... G0800730 309... 9........... 0.005. 100 Q8Q0Z3i 649. 65 0.007. 206.00. 207.00 1.00... G0800732 399.... 109..... 0,005. 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.  199.00. 199.00. 200.00. 20.t00.  000_  3.00°ooo< Proximal to veinslin matrix Chlorite 2.00°e<i Biotite 3.00°c*< Pervasive  04007iL S01 080Q71L 140 G0300717 192.00. 193.00 100 193.00. 194.00 lolL. G0800718 829. 194.00. 195.00 lOlL. G0500719 .599.... 195.00. 196.00 100... G0800720 195.00. 147.50 i5L.. G0800721 149.... 0.50 0800Z2L 149. 198.00.  spacing. Locally finely disseminated sulphides; distribution not consistent. QZ-CP-PY veining.  Magnetite 3.00°ea Disseminatedlin QZ veins  59.....  190.00.  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,  ‘14_...  G0800709  0400Z11 553 G0500712 459... 147.00. 188.00 100 148.00. 189.00 1.00.... G0800713 519..... 149.00. 190.00 100_ G0800714 57L  I  I  -  G0800708 1.00  195_  I9ZAL...219.OO_Breccia Hydrothermal(?)  144.00 100....  184.00. 199.00. .tQ0_. 100  I  20.00mm> 0 <@182.50 QZ-MO Vein 85.00 <@189.90 QZ-CL Vein 75.00° 40.00mm>  p  581.....  G0500699  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 169.10- 170.10 Chalcopyrite 0.10%o o< 184.90- 170.75 patchy Magnetite  p°m 12  lTh00. ff7.00 0.00 0400700  <4  pm 339  a 169.10- 170.10 Replacing PF & mafics Sericite 3.00°ca 183.80- 184.10  0.30%a  t’)  Width  179.00. 171.00 100_  175_  00  To  40  °graphiclognottoscale  200.00 200.00 201.90 202.00  Page  Project: Taseko From  To  Hole Number: O8TSK-02  /  Rock-type & Description  <@202.50 CY-rlch Fracture 60.00°>  0  210  ,  50  3  0  05 0  5  ‘  From  To  Width  Sample  Cu  Mo  ppm  ppm  Au  ppm  <  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> <@217.70 QZ-PY-CP Vein 85.00° 20.00mm>  215  224.00_Diorite  J  Medlum-grained, porphyritic diorite. Core competency varies from poor to 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. 0 \h  <@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  °2*’  c \°  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> <@225.25 QZ-PY-CP Vein 60.00° 4.00mm>  -,  -8  235  <@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°> < 236.60 QZ-PY Vein 60.00° 20.00mm>  2008111103  °21  Equity Exploration Consultants Ltd.  \ °graphic log not to scale  Page 9ofll  Hole Number: O8TSK-02  Project: Taseko From  To  1  Rock-type & Description  Au ppm  Width  Sample  240.00  241.00  1.00  G0800769  1005  63  0.007  241.00  242.00  1.00  G0800770  637  108  <0.005  242.00  243.00  1.00  G0800771  1050  104  0.013  243.00  244.00  1.00  G0800772  1085  112  0.011  244.00  245.00  1.00  G0800773  616  94  <0.005  245.00  246.00  1.00  G0800774  414  22  0.005  246.00  247.00  1.00  G0800775  321  8  <0.006  247.00  248.00  1.00  G0800776  704  43  0.006  248.00  242.00  1.00  G0800777  754  106  0.007  249.00  250.00  1.00  G0800778  1015  34  0.007  \,°‘  250.00  251.00  1.00  030800779  1185  48  0.011  IS  251.00  251.00  0.00  030800780  :  251.00  252.00  1.00  030800781  900  32  <0.005  :  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  254.00  255.00  1.00  00800785  255.00  256.00  1.00  00800786  886  60  0.006  256.00  257.00  1.00  (30800787  1650  149  0.01  257.00  258.00  1.00  00800788  782  88  0.005  258.00  259.00  1.00  00800789  496  37  <0.005  259.00  260.00  1.00  (30800790  1540  64  0.006  260.00  261.00  1.00  00800791  513  12  <0.005  1  261.00  262.00  1.00  00800792  887  79  0.005  1  262.00  263.00  1.00  00800793  1165  69  0.008  263.00  264.00  1.00  G0800794  570  61  0.005  264.00  265.00  1.00  00800795  568  109  <0.005  265.00  266.00  1.00  00800796  716  68  <0.005  PY Fracture 50.00°>  266.00  267.00  1.00  (30800797  677  30  <0.005  QZ.PY Vein 70.00° 30.00mm>  267.00  268.00  1.00  00800798  333  51  <0.005  QZ-PY-MO Vein 45.00° 70.00mm>  268.00  269.00  1.00  00800799  668  71  0.005  269.00  270.00  1.00  00800800  826  84  <0.005  270.00  271.00  1.00  G0800801  910  49  0.005  271.00  272.00  1.00  030800802  644  32  <0.005  272.00  273.00  1.00  030800803  903  141  0.005  273.00  274.00  1.00  G0800804  380  12  <0.005  273.00  274.00  1.00  00800805  0  50  0  0  0  4 IS  4  0  4  0  5  0  QZ-PY Vein 70.00° 5.00mm> °°5  \‘ \10°  ,(  \oo° 245.00  5  240  QZ-PY-MS Vein 85.00° 20.00mm>  @ 240.25 < ct 243.40 <  I  304.20_Andesite  zs  1  Fine-gralned, aphanitic In places. Moderately to strongly magnetic (MG-BI alteration). QZ-PY-CP-MO veins (sulphides minor) with MS selvages, typically 2  J  .  \,c$5°  to 15mm wide and 60-80 degrees TCA. ‘.  o  280.25- 280.50 Igneous texture destroyed, bleached Silicification 4.00°ooi  Pervasive overprint Chlorite 2.00°eso Secondary in clasts Biotite 2.00°ae Alteration of clasts Magnetite 3.00°c  44  Chalcopyrite 0.50%ss  44  Pyrite 1.50%ss  c  Molybdenite 0.10%uso 245.00- 258.50 Chalcopynte 0.30%sos 262.50- 269.40  zoo I <@245.60 QZ-CP-PYVein85.00°5.OOmm>  @ 245.60 CY Fracture 75.00°> < @ 247.10 QZ-MG-CL Vein 60.00° 3.00mm> < @ 247.60 QZ-PY Vein 78.00° 6.00mm> < @ 249.85 CL Fracture 55.00°> < @ 256.60 PY Vein 80.00° 5.00mm> < @ 257.10 PY-QZ Vein 4.00mm> < @ 257.80 CL Fracture 89.00°> <  °  ;_i 264  < <  :.  . ,_  \  .  259.30 CL Fracture 80.00°> 1  @261.43 QZ-PY Vein 75.00° 17.00mm>  @ 262.07 < @ 262.30 < @ 262.50 < @ 263.70 <  QZ-PY Vein 80.00° 20.00mm>  <@264.06 PY Fracture 70.00°> <@264.20 QZ-PYVein56.00°10.OOmm>  @ 264.80 < @ 269.40 < @ 269.50 < @ 270.25 <  2008111103  I  I  ..  \j10’  270 .  QZ-CP-PY Vein 75.00° 35.00mm>  .,  QZ Vein 78.00° 25.00mm>  \‘  CP-CL Vein 90.00° 4.00mm> QZ-MS Vein 70.00° 8.00mm>  .  4  -  <@258.85 aZ-CL Vein 70.00°30.OOmm>  00  Mo ppm  Cu ppm  To  0  From  ‘  .__k  .  0  ,-  :  Equity Exploration Consultants Ltd.  “°““°“““  -  *graphiclognottoscale  °°°‘°“°“°  f’ n,’° Page lOofil  Project: Taseko From  To  Hole Number: O8TSK-02  Rock-type & Description  j  From  To  Witii  --  5  3  0  6  5  0  40  no  no  82OOARO7  58  n nos  30i_ 44_ 35___ 58 85 2L_ 21L_ 2L_  6.05 Q.09S 0.00_  7R  278.0 271.0 278.0 278.0  <@282.40 PY-CP coating Fracture 75.00°>  281.0 282.00 283.00  2Th9 t90_ (30800808 278.0 L0Q_ (30800809 2Z941Q. 1.0_ G0800810 fl89Q81i 30Q& 1.0Q 281.0 tDL Q8QO812 282.0k tOQ_ (30800813 283. tOQ_ (30800814 (30800815 Z84.0 t98  <@282.80 QZ-MG Vein 45.00° 40.00mm>  284.00  285.Q L0Q_  (30800816  538_  18._ Q.00S  285.00  2li.0 tOQ_  (30800817  79&  44.  286.00 287.0 tDQ_ (30800818 287.00 288.0 t2L Q89Q8i9 285.00 2I8.J3 0.0Q_ (30800820  42&  808  IL_ Q.00S 3Q %QQ8 OL_ 0.005  F  <@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  280  296.0  <@278.30 PY-CL Fracture 4.00°> <@281.70 QZ-PY Vein 80.00° 5.00mm>  <@283.30 QZ-CP Vein 86.00° 6.00mm> <@283.50 QZ-CP-PY Vein 55.00° 30.00mm>  283..  <@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>  200..  i  Au -  7S On  <@280.00 CL Fracture 80.00°> <@271.00 QZ-CP Vein 50.00° 10.00mm>  782 680  53J_ °,12 475  40L 1.02526.  Q.00L  289.0  IJIQ_  (30800821  5Q4_  289.00  290.0  tO_  (30800822  309_  18._ Q.05  290.00  29t0  tOQ_  (30800823  625_  3L_ Q.05_  29QQ 292.0k iO0.  <@298.80 QZ-PY-MG (MS selvage) Vein 65.00° 5.00mm> <@299.10 QZ Vein 65.00° 25.00mm>  291.0  292.D tDO  Q8QQS24 48L  Z7 6.0S  (30800825  292.0283.00. tOL Q8QQ82L 68L 293.0 284.00. tDQ_ (30800827 105L 294.00 295.00. tOO_ (30800828 1Q80  295..  6.005 Q.093 6.0S  285.00  <@296.50 QZ-CL Vein 56.00° 35.00mm>  <@301.90 QZ.CP (CL selvage) Vein 89.00° 20.00mm> <@302.00 CY Fault 65.00°>  2L  0.05  60 0.01_  4L_ Q.OOL  <@302.50 QZ-CL Vein 70.00° 40.00mm>  295.0  296.00.  tQQ_  G0800829  804  65  <@303.20 QZ-PY Vein 60.00° 4.00mm>  296.00  297.00.  tlIO_  (30800830  3.07_  52_ O.00.  <@303.90 QZ-PY Vein 90.00° 5.00mm>  297.00  298.00.  1.00_  (30800831  684  4 Q.0Q5_  31L_  300  298.00 299.00. tO_ (30800832 289.00 300.00. tQQ_ (30800833 30.00  301.00.  t0Q_  (30800834  617  301.00  3.02.00.  1.00_  (30800835  I1OL  12L_ 0.09_  2200  28L_ Q.OIL 222_ Q.01t  303.00 4041 20  (fl 20 FOH  2008111103  Q.01I  7Q Q.OQt 0fl Zt 28__ Q.009.  !88_  -  302.0 303.00. t0Q_ G0800836  00  Mo  Sample  304.20.  t2L.  (30800837  t1QL  I  Equity Exploration Consultants Ltd.  °graphic log not to scale  — —  Page 11 of 11  ,A,  • EQUITY  I I  EXPLORATION CONSULTANTS LTD  Project:  Taseko  Collar elevation:  Hole:  O8TSK-05  Azimuth:  110.00  Proposed:  O8TSK-E  Dip:  60.00  Location:  449473 m East  Prospect:  NW Copper  Claim:  354055  Logged by:  L Hollis  5671695 m North  2192.Om  Length:  310.30m  Date started:  Date completed:  2008/08/12  2008/08/22  Objective: .  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: 14.6 27.4: 27.4 36.3: 36.4 54.3: 54.3 58.7: 58.7 139.5: 139.5- 158.2: 158.2- 184.5: 184.5- 218.8: 218.8- 249.0: 249.0 281.9: 281.9- 310.3: -  -  -  -  -  -  -  Casing Andesite. Strong CY-alteration. Fracture-coating FE 1%. Undifferentiated Volcanic. Strong clay-alteration. Andesite. Moderate CY-CL-alteration, weak EP. Undifferentiated Volcanic. Strong CY-alteration. Andesite, minor undifferentiated volcanic. CL-MS-alteration. 0.2% PY. Andesite. CL-altered. CA-GY + QZ veining. Undifferentiated Volcanic. CA-QZ veining. Volcaniclastc. CA-GY+QZ veining. HE on fractures. 0.1% PY. Andesite. CA-GY veining. CL-alteration. Andesite, minor volcaniclastic. CA-veinings. Local MS-alteration. Volcaniclastic, minor andesite. CA-GY veining. CL-alteration. 0.1% PY. -  186  00  0 01  C),  0  p  0  0)  0)  0)  0)  0)  0  o o  0  0 0  (3 0  0  -  0 0  boo  0)  o)r3g)o  N  -.  —  CD  ‘S a’  4  I  —.  0 G)  I I I  ci  P  iz  —  C -l -<  m  A  CD D) ICfl Cl) CD  CD —  b  -  Project: Taseko From  To  Hole Number:  j  Rock-type & Description  From 0  0.00  14.60_Casing  20  4  0  40  40  40  40  0  To  Width  sample  Cu  Mo  EE J  Au ppm  4  I  10  14.60  O8TSK-05  21.30_Volcanic undifferentiated  —  I  1440_ 2L30_  5.7Q_  G0811370  9L_  2__ Q.QOL  21.30  24.40  3.10  G0811371  217  1  0.008  24.40  27.40  3.00  G0811372  195  1  0.006  77 tA  20  On  2 CA  snaiism  ‘1R7  C  A Al  90 On  4, Ofl  s nfl  IA0ll17A  197  Core is bufflcream-coloured and composed of clays and rock fragments. Rock is  l9 On  Sq On  i  nn  Kfl0ll17C  09  C  A A19  strongly altered to clays. Can see rare relict FP(?) phenocryst sites. Fe-oxides are present imparting orange-colour to core.  51 On  IA On  I flfl  tiUttll3Ib  a’  ‘I,  A fllC  -  Core competence is poor milled rock, with core loss. Bleached rock with FP -  —  phenocrysts. Protolith could be feldspar-phyric andesite. Surfaces coated with  “V  fe-oxides. “V  20  21.30  27.45_Andesite  —  I  “V  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  25  Fracture-coating Fe 4.00*00 Alteration of FP phenocrysts Sericite 2.00o  27.45  36.34_Volcanic undifferentiated -  —  I 30  —  ta On  -  A Al  fln241177  a Core is CY and rock frags Clay 3.00*0 35  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  cc cc  2008111104  Equity Exploration Consultants Ltd.  [  ,MQ  1.Q0_  G0811378  124__  5___ 00QL  z.3Q__ 39.QQ_  tZQ_  G0811379  14L_  4__ Q.0i_  39.QL  t7Q  42.QL  3.40_  051i3 G0811381  12L_  4___ 0005  Z.3Q  graphic log nottoscale t  Page 1 of 12  Project: Taseko From  To  Hole Number: O8TSK-05  j  Rock-type & Description  004  from 38.5 to 42 m fault zone? FP phenocrysts account for —25%. CL+i-EP  0  3  0  4  0  4  0  4  0  40  40  4  0  -  40  alteration of phenocrysts. Densely fractured, no preferred orientation. Fractures coated with fe-oxides, impart a  4  Cu  From  To  V4dth  Sample  40.70  45.10  4.40  G0811382  143  Mo  Au  8  0.011  —  rusty discolouration to core.  s Chlorite 2.00°c c Epidote 2.00°c s Staining on fracture surfaces Limonite  2.00°c  45.10  54.30_Andesite  I  45.10  51.20  6.10  G0811383  113  12  0.013  Black andesite, core competency is poor to moderate. Dense fracture network  51.20  54.30  3.10  G0811384  90  6  0.006  (coated in Fe-oxides) giving core rubbyibroken texture with angular void  51.20  54.30  3.10  GOSI 1386  54.30  57.30  3.00  G081l386  144  7  0.009  57.30  58.70  1.40  G081l3a7  91  5  0.009  58.70  60.20  1.50  G0811388  112  9  0.006  60.20  63.40  3.20  G0811389  95  12  0.01  L  01L  spaces. Up to 20% FP phenocrysta; CL-altered. Limonite and Fe-staining on most  surfaces.  50  —  c 45.10- 45.30 Bleached Clay 3.00°c os 45.30- 45.30 Alteration of FP phenos Chlorite 2.00*5  .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  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? -  <@ 60.07 FE Fracture 60.00°> <@ 59.80 FE-EP Fracture 70.00°>  60.25  60.94_Volcanic undifferentiated -  50  —  \r  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. c 60.25- 60.40 angular fragments, CY-rich Fault Gouge Zones  inqA GO  2008111104  cn  ms& m  Equity Exploration Consultants Ltd.  *graphic log not to scale  Page 2of12  Project: Taseko From  To  Hole Number: O8TSK-05  j  Rock-type & Description  From  ,  To  Width  Sample  Cu -  0  54  0  3  0  4  4  4  5  4  0  4  4  Mo  Au  --  4  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  05.50  L  t  phenocrysts now soft. Dense fracture-network, with no preferred orientation,  64.SQ_  5Z.5Q  tQQ_  G0811393  tlL_  4___ 0.005  coated with FE; Intensely fractured with FE from 68-69 m. Clots of FE material  SZ.5Q_  685L  tQQ_  G0811394  134_  4__  between 68.96 and 69.36 m weathered from vein material?  64.40_  89.SL  1,Q_  G0811395  IOL_  3____ Q.QQ6_  ga_sn  7fl50  ton  66  4  00flg  70Sfl  7150  aon  (SnRit’457  en  i  <n_one  71 50  72S0  inn  5351511355  SR  1  0 0n7  7Sfl  7255  InC  Liusll.sss  un  IC  tflflflC  73.65  74.50  0.95  G0811400  64  <1  <0.005  74.60  75.60  1.10  G0811401  61  <1  0.005  Th.60_  Z8.40  3.0Q_  G0811402  1Q.4..._  t___ 0.QQ5  Th.6Q_  9,4Q  G0811403  79.5Q_  6QS0  7L_ 73_  3__ Q&0L  Dark grey-green PF-phyrlc andesite, core competent. Flne.gralned matrix.  tQQ_ tQQ_  Locally rounded clasts. Zones of CY alteration sporadically throughout the  79.5Q_  6Q.5Q  1.QQ_  G0811405  61_en  1fl0  -  Q.t12_  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  I  72.50_Andesite  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,  <4  V. Vv VV V. VV  mm-scale clasts of andesite.  VV V. VV  Clay 3.00°a  Z35L_76.O4_Andesite  I  VV  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  .interval (light buff and softer) which are proximal to intense fracturing. 2008111104  Equity Exploration Consultants Ltd.  *grephic log not to scale  G0811404  Z__ Q.Q05_  Page 3of12  Project: Taseko From  To  Hole Number: O8TSK-05  /  Rock-type & Description  050  38  40  45  40  48  4  0  To  WkIth  Sample  81.60  82.60  1.00  G0811407  62.60_  83,5Q_  Cu  Mo  EE  EEL  Au  ppm  4  Fractures are coated in FE, impart a orange (rusty) colouration to the core. FE 80  From  -  0.006  84.60_  8S.50_  tOQ_  G0811410  8S.60_  65.60_ L00_  G0811411  4t_  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  86L  8L60  LQ  SLSL  Q5114IL 9 4 0QL 8S.2Q_ Q.SL_ G0811413 t13_ 4__ .00L  aft  85  0.S0_  1  o Pods Hematite 0.50%so 78.55- 79.25 Clay 2.00*50 Alteration of FP  stingers mostly 1 mm wide.  L00_ G0811408 M50_ t00_ G0811409  76  t__ 0.OL 80__ 1i.._ 0.POL 9L_ 4__ Q.005  stringers are common. Poddy and stringers of HE throughout the interval,  90_  5__ 0.QOL  —  <@ 82.97 CY & andesite fragments Fault Gouge 60.00°> < 76.10 CV Vein 60.00° 10.00mm>  88.20  I  91 .70_Andesite  Dark grey to light grey-yellow (changes with depth). Core competency is poor;  4  coherent rock that is crumbly with most forming small angular chips. Strongly clay-altered with relict phenocrysts (assumed to be FP andesite protolith). -  o  Bleaching and softening of core Clay 3.00°a  9°  -  909  as  9fl  -.-——  I 0909  55U011414  In,  9  n nns  as ,n  Sn  909  4 nfl  53U511415  ‘A  9  A Afl7  on  ci  ,n  a nn  7A  A  A Al  o.,.,n  4 nfl  flflQ4iAl7  CO  A  A flflA  a  flflDálAlQ  CO  A  n nn7  909  ..-  <@ 91.02 GYVein 60.00° 2.00mm> <@ 91.05 GY VeIn 80.00° 30.00mm> o4’)n  QI 7fl  lfl A An,i  In  Light grey-green, altered andesite with relict FP phenocrysts. Core competency  93.90  °  is very poor; core crumbles on contact and is mostly in rubbly sections. Up to  96.90  96.90  0.00  35% tabular PF phenocrysts. Mafic minerals are strongly MS-ICY-altered.  96.90  97.90  1.00  102  0.007  97.90  98.90  1.00  114  0.007  9890  9990  1_no  119  99_go  10090  1_no  120  99_go  l0O90  1_no  10090  101_go  100  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 -  -I  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  ,,.,,,__  010811419  flflO44Afl  131  0.008 <1  <0_flos  n_one  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>  2008/11104  Equity Exploration Consultants Ltd.  °graphic log not to scale  Page 4of12  Project: Taseko From  To  Hole Number: O8TSK-05  Rock-type & Description  o .—  0  50  30  4  4 i  0  4  0  4  From —  To  Width  Sample  Cu  Mo  Au  i  —  101.90  102.90  1.00  00811427  2Q  W80  tQ  Q8ii42L 12Z t  Dark purple coherent andesite. Core competency is poor to moderate. Andesite is  W80  W6J  20  FP-phyrlc (25%) wIth a dark maroon, aphanitic matrix. All phenocrysts are  6i  t09J  Q8fl42L 12L i_ QQ6 i43Q 1Q8 1_ 0QL  altered to CL. Chlorite Is ubiquitous as fracture-coatings, phenocrysts, and  i5.j  110.fO  LQ0_  00811431  114_  t_ Q.005  110.10 112.10 11210 115.10  20Q_  00811432  114_  3__ 0.00L  210_  G0811433  IOL_ L__ QIOL  fl00.0  99  102.60  115.20_Andesite  I  veinlets. Fracture-coating PYthroughout interval, with hematite-staining.  —  Rare GY fractures.  107  1  0.006  QL  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°> 115.10  115.20  1  121.50_Andesite_  1.ona.0*.  ,,ne,.,,  118.10  <1  0.006  104  0.02  63  0.008  12030  122.50  2.20  l1Ofl  l&Afl  )5fl  124.40  12L4 30D_  00811438  112__ 1__ Q.OQL  127.40 130.00  13010.  00811439  80._  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  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  2flOllA7  IRS  I  0 flflC  Alteration of FP Sericite 3.00*00  Pyrite 0.75%o  124.40  139.50_Andesite  I  Core is rubbly, locally competency increases. Andesite is generally porphyhtid 5 In texture, with FP- and HB-phyric zones. HB-phyrlc andesite with CL alteration 2008111104 LJ  Equity Exploration Consultants Ltd.  I  -  *graphic log not to scale  -  131.50  --  21L 1.50  .  .  SI  1___ 0105_ 0.006 Page 5 of 12  Project: Taseko From  To  Hole Number: O8TSK-05  Rock-type & Description  From  To  Width  —  —  (pervasive and on fractures) from 120.0- 129.60 m and 131.0 133.0 m. Above  1’41 On  l’0’, On  and below this is the typical maroon FP-phyric andesite. Flow contacts are  133.60 133.15  30  St  4  Sample  Cu  Mo  Au  —  0! ‘,flfl  flflRl 1554  7,  6QQ_  G0811442  75___ 6___  ei  n fine  -  Q.QOL  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 126.15128.45 Fracture-coating Pyrite 0.60%a 135_  <@132.75 GY Fracture 65.00°> <@132.82 GY Fracture 80.000>  139.50  I  152.95_Andesite  an  020611445  40  ,  n ni  isi nn is, an  i en  02061i444  47  ,  n fine  andesite (25-40% squat- subrounded phenocrysts) in a maroon flne-gralned  isi nn  is, an  i en  matrix. Trace pyrite. Rock is intensely fractured most fracture planes are  is,  an  isa fin  i an  020611440  is,  a,  n fine  coated with HE-CL-GY.  ,aAfln  iagnn  ,nn  flflfluIAA7  IC,  iACflfl  lA7flfl  inn  Dark purple-greenish coherent andesite, core competency is poor. FP-phyric  jq  140_  -  an  iai  no  I  —.— -._.=_=—  -  7,  —4  -n fine  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  IF  148.50  150.00  1.50  G0811450  139  <1  <0.005  150.00  151.60  1.50  G081 1461  120  <1  <0.006  St  <1  <finns  <1  <n nna  <1  <n nna  <@147.90 CL-HE Fracture 55.00°> <@149.50 GY-CL Fracture 40.00°> <@152.56 HE-GY-CL Fracture 25.00°> isian  iann  ian  1a<nn  iaan  Ian  tInSi iaao  Dark purple medium-grained andesite. Core competency is poor-angular clasts  iasan  laann  ian  L2Uo11q44  as a,  fill interval. HE-staining on most fractures. GY veining (white, soft, does not  taann  15700  ian  020811440  75  Si  <n nna  fizz with acid) is the dominant vein4ype. Cross-cuffing veinlets, average a  1R7  an  04.0.45  !&LtL_  0,0011000  0<7  Si  <n <ma  158.20  159.70  L5Q_  158.70 161.20  15i2 t62  G0811457 51___ 1__...... Q5L 33 <1 <1 G0811459 40  152.95  1 58.20_Andesite  I  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>  Nt  <@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.  *graphic log not to scale  164.00  2.80  <.6Q5 <0006 <0.005  Page Got 12  Project: Taseko From  To  Hole Number: O8TSK-05  j  Rock-type & Description  0  4  0  4  0  4  (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> <@180.00 QZ Vein 80.00*3.00mm>  170_  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 later CA-GY veining.  2008111104  198..  Equity Exploration Consultants Ltd.  °graphic log not to scale  Page 7of12  Hole Number: O8TSK-05  Project: Taseko From  Rock-type & Description  To  From  1  o 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-  so  r  2  5  4  5  4  5  4  0  4  0  4  0  4  lasso  To 19550  Width  Sample  Cu ppm  ina°  100.5Q 107.50 iQQ_  G0811479  i57.sa 1050 I00 Q81i450  Mo ppm  Au ppm  a 93__ 5___  <Q.QQ5  101  2  çQ.5fl5  202.50 Disseminated & in veins Hematite 0.50%as 184.50- 212.00 Pervasive  10S.50  109.50 1.00_  G0811481  132_  t__  Q.Q0&  Chlorite 1.50°ea 207.60- 209.70 Finely diseminated Pyrite 0.10%a  109.50 200.50 1.5Q_  G0811482  SL_ t__  Q.OQL  200.50 201.5w 201.5k 202.5 2Q3.5 205 2Q5.5  G0811483  IQL_ t__  <iLQQS  Q811A8L Q8114SL Q81L Q8415L Q4014S 021i4S  99 t c0.005  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> 202_  <@191.00 CA Vein 45.00° 2.00mm>  201.50 200.50 202.50 203.50 204.50 203.50 205.50  1.QQ_ iQQ 1.5Q i00 iQQ 150 1.50  11L t cO.5Q5 109 t c0.006 101 0L 77 t <006  20L50 10000 63 t <006 1.5Q 128 t <006 2Q9.5L 209.50 1.50_ G0811492 13L_ 2__ -Q.006  <@191.80 CA-GY (minor CL at margins) Vein 85.00° 25.00mm> <@194.80 CA-GY Vein 20.00° 30.00mm>  2Q5  2QL5 203.50  <@196.80 GY-CA Vein 35.00° 28.00mm> <@199.35 GY Fracture 40.00° 2.00mm>  209.50  <@200.70 CA Vein 35.00-45.00° 1.00-5.00mm> <@202.90 QZ-PY Vein 30.00-15.00° 10.00mm>  210.50 100_  210.5 21150 100 205_  211.59.  213.50 1.0Q_  (30811493  cQ.oQS  051J49L  13L_ L_ 405 <1  0.0Q5  (30811498  SL_ 4__  9.005  <0.005  <@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> 210_  <@214.60 CA Vein 85.00° 35.00mm> <@215.55 CA-CL Vein 25.00° 2.00mm>  212.50  213.50  1.00  95  I  213.50  214.50  100  72  Similar to above variation in colour and dominant igneous texture only. HB  214.50  215.50  1.00  184  <1  0.005  phenocrysts. Still voicaniclastic likely andesite in composition. Decreased  215.50  21650  tOO  99  <1  0.005  veining moderately veined. Weak-moderate CL alteration. CA-GY-QZ composite  21&50  21650  000  veining, but CA dominates. HE on fractures and often associated with veining.  21650  21750  1_On  114  <1  <a-ens  Locally pinwred hue-HE staining?  2I7SO  2l9Sn  1aa  so  212.80  218.80_Volcaniclastic -  -  -  215_  5  <0.005  <aans  <@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> 2008111104  Equity Exploration Consultants Ltd.  *graphic log not to scale  Page Sot 12  Project: Taseko From  To  Hole Number:  Rock-type & Description  From  y 0  3  0  4  0  4  0  4  0  4  0  4  0  I  2I$L246.50_Andesite  O8TSK-05 To  Width  Sample  Cu  ,lacn  ,laen  Inn  tue1,5u3  0  ‘40  100  GQIQ  ....  Dark green, medium-grained andesite, core competent. HB & FP phenocysts (t  21Q  ‘.2Q0 tO_  G0811505  a2Q.50  2i50  tQ0  Q24i 24  wide up to 20 mm; —90 and 70 to core axis. HE on fractures typically  22L40  ‘.22.40  100  G0811507  70_  asociated with CA veining and fractures.  222.40  223.40  LQ0  GOBI 1508  63.  a  Fracture-coating & around vein margins Hematite 0.50%aa Calcite Veining  1.50°c  s  223.50224.50 t00 224.50 23.Q0 3.50  225  Alteration of HB Chlorite 1.50°cc 240.20- 245.50 Calcite Veining  2.50°c  <@230.60 CA Vein 70.00° 20.00mm>  230_  4  <@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_  024i40 94 040Ii 7  1  005  Q05 j__  Q.0Q5  2  0Q5  2  G0811511  45  005 4_ Qg5  230_  G0811512  toL_  t__ Q.Q08  UQ  2 120  223.00  220.40  1.5Q_  220.50  231.40  231.50233.30 <@229.73 QZ-CA-GY Vein 65.00° 10.00-15.50mm>  Au  4  20% HB, 15% FP) in fine-grained matrix. CA+i.QZ-GY veining (typically few mm -  Mo  233.30  224.20  IAO_  O0311iI (24811514  234.70  236.40  tZQ_  G0811515  236A0 ULOQ  t5Q  0311I  237.00  ‘.30.40  1.50  (24811517  ISL  3.  230.40  240.0  L50_  GOShISIS  t31  0.305  240.00242.40  Q81L 91 G0811520  2  Q.QQ  343.90 ‘44A0  t60 t50_ 0.50  <L 1  G0311$21 8  1  95  344.40  ‘Ai90  L5Q  L 0.005  245.90  246.30  340  031i52L (24811523  133.  4 Q.090  246.40  247.90  1.60  G0811524  110  1  <0.005  246.40  247.90  1.50  G0811525  247.90  249.40  1.50  G0811526  91  1  <0.005  242.40  243.40  IOL_  i __  0.0Q5  3.  4 Q08  10.L  05  240_  245_  2Aft fl  9A0 AG  1.  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>  2008111104  Equity Exploration Consultants Ltd.  °graphic log notto scale  Page 9of12  Project: Taseko From  To  Hole Number: O8TSK-05  Rock-type & Description  From  ?  —  0  3  0  4  0  4  0  4  3  4  0  To  Width  Sample  —  Cu  Mo  Au  E!L.  —  4  <@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>  249.00  0!  259.20 Volcanicbstic  00811527  249.40 250.90 260.90257.40  t50_  Purple-dark grey, medium- to coarse-grained volcaniclastic. Core competent Locally porphyritic and HB-rich (30%). Sub-rounded clasts of feldspar.phyric  252.40  253.90  t50__  00811529  andesite. Weakly developed CA veining (typically few mm). No mineralization  ‘302  On  ‘300 An  I Cfl  (i0311530  I  observed.  ti Q6I1528  91___ 1___ <0.Q06 °,2 4t t__  c0.005  256.40 256.90  t5Q_ 00811531  85  f_ Q,ggL  256.90  258.40  1.50  74  <1  256.40  259.90  t5Q_  00811533  83.  SI <0.006  t5L  00811534  103_ t__ <.0.006  <0.005  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°>  259.20  \t°  298.10 Andosite  259.90 261.40  Dark grey.green porphyritic andesite. Core competent Phenocryst population  251.40 252.90  LS0_ G0811535  IIL_ Si_ <.0406  (—10 up to 35%) dominated by squat HB phenocrysts, locally CL-altered. Also FP  262.90  1.50_  G0811536  phenocrysts are altered to CL-MS. Irregular CA veins with diffuse margins  254.40255.90 t40 L 116.  12L_ £L_ 0.005 <1 %0Q5  (typically less than 5 mm wide, unmineralized, 55-70 to core axis). Moderate  266.90  257.40  L50_  00811538  1iI  pervasive CL alteration, with CL-EP selvages. Thin microveinlets with  257.40  256.90  t50_  00811539  79.  alteration haloes of ms(?). Trace HE particularly along fracture planes. MS  257.40  265.90  l4tL_  00811640  alteration around cluster of CA veins at 279.6 m.  255.90  270.40  t50_  260_  -  254.40  G0811541  L_ 0.00S  cQ.0QS  82. L_ 0.005  70.40 271.00 1.00  40SI1ML 93  276.2 and 278.6 m: FSPO, gradational contact, medium-grained and locally up to  271.00  00311543  20-30% phenocrysts.  273.40274.90 L60  051i644 64L  andesite of varying Composition and phenocryst content Vary from FP-phyric (up to 3 mm, squat) to phenocryst-poor, almost aphanitic andesite. FP phenocrysts  2_13.40 274.90 274.90 276.40 276.40 277.90  1.6Q L6Q_ 1.SQ_  00811545 00311546  exhibit flowtextures, flowing around clasts. Chaotic igneous texture. MS  271.90  279.40  1.6Q  00811545  141  <1___  alteration at both the upper and lower contact with the dark green andesite.  279.40  280.90  1.5Q_  00311549  77  j__ <_0.0QS  IOL <1____ <Q.005 57 <1 c0.005  281.9-282.8 m: VCLC. Dark maroon volcaniclastic with sub-rounded clasts p265  —  273.40  1.60  00811547  250.90  26.1.90  1.00  00811550  282.8-298.1 m: Pervasive alteration surrounding a 8 cm wide, massive QZ-CA vein  281.90  ‘.47.80  0.90  with fragments of host rock and a dark mineral disseminated (tetrahedrite?),  262.90 ‘.64.80 L6L  0511551 00811552  that is typically associated with PY.  284.90  00811553  2008111104  Equity Exploration Consultants Ltd.  *graphic log notto scale  ‘.65.80  1.6Q_  109.  Q.0QL j 2  <0.006 c9.0Q5  137 L_ <0.0Q5 L_ <0.005  94  cQ.006  18L  L_ cO.005  15L  2__ 0 ’l.02L Page  Project: Taseko From  To  Hole Number: O8TSK-05  Rock-type & Description  From  / 8  50  4  0  40  40  40  40  4  270_  <<Alteration of HB & in veins Chlorite 2.50°s a 259.20- 269.80 Epldote 1.50°a  285.80  To  Width  287.30  1.50  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*  o°pm  p°m  111  2  st  pi 0.031  255<SP 14Q_ 2SS,8G SQ 1.S 25030 29t80 tSQ 2SI.G LSQ_  G0811555  4L  G0811556  94_  G0811557  112 t__ 0.0lI5  G0811558  1i8__ 1____ Q.QQS_  283.30  284.80  L80  G0811559  14L  254.80  286.30  t5  (28811580  04. t__ Q.QIL  28Z30  <<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  Sample  —_---  L_ 0.005  <@259.50 CA-PY Vein 30.00° 10.00mm> <@262.10 CA-EP (at margins) Vein 40.00° 4.00mm>  27<  —  <@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°>  280_  IE_  <@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>  0<5  <@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> 2008111104 00  290_  Equity Exploration Consultants Ltd.  *graphic log notto scale  Page 11 of 12  Project: Taseko From  To  Hole Number: O8TSK-05  Rock-type & Description  From 50  <i  00  40  40  40  40  4  0  4  0  To  VAdth  Sample  pm  p0m  p  4  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°> <@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>  290_  <@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 0  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 Sericite 305  00811561  t55  <j  Q0j  298.40  G0811562  94  <1  0.006  00811563  W2  00811654  9S___  ‘c1._ Q..QQL ci____ ooos  00811566  144_  j  G0811567  95____  299.90  1.50  259.00 3O1AQ .tSQ_ 0i.40 302.OQ j.5Q__  maroon andesite which become larger with depth. Sharp clast boundaries, so3with veins exploiting the contact. VaryIng phenocryst content. CL-MS alteration  255..30 250..40 2JQ  -  1.00°.  01.4P 02.00 1SQ__ 04.4Q t00_ 04.4 30590 tSQ_. 05.50 30L4Q t5Q__  00811565  00811558  52  7.4Q 0000  t50_  00811569  tlL_  1____ 0005_ <1____ 0.0Q5 1_.. Q.0PS  Q8.9 3iQ3Q  t40_  00811570  12L..  L  .005  Q.000  <@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>  jQ_31O.3O_EOH___________________________________  2008111104  Equity Exploration Consultants Ltd.  *graphiclognottoscale  — —  —  Pel2ofl2  ,A,  • EQUITY  EXPLORATION CONSULTANTS LTD.  I I  Project:  Taseko  Collar elevation:  Hole:  O8TSK-06  Azimuth:  320.00  Proposed:  O8TSK-D  Dip:  -65.0°  Location:  453337 m East  Prospect:  Hub  Claim:  354057  Logged by.  L.Hollis  Drilled by:  No Limit  Assayed by:  ALS Chemex  Core size:  HO/NO  Dip tests by:  Reflex MS  5668764 m North  Length:  1592.Om  304.80 m  Date started:  Date completed:  2008/08/23  2008/08/28  Objective: O8TSK-06 was collared 150 m to the southeast of drill hole O8TSK-03, in the mag low.  SUMMARY LOG: 0.0 9.3 m: 9.3 77.Om: 77.0 86.5m: 86.5 91.Om: 91.0 159.lm: 159.1 - 161.Om: 161.0-256.5m: 256.5- 269.8m: 269.8- 274.lm: 274.1 -278.4m: 278.4-304.8m: 304.8 m: —  -  -  -  -  CASING. DIORITE. MG-Bl-altered. QZ-veins. Localized MS. CP:0.3-3%,PY:0.3-3%, MO: 0.01% BRECCIA Intrusive (?). MG-Bl-altered. QZ veins. CP:1.5-2%, PY-1.5%, MO: 0.01-0.03%. GRANODIORITE. CL-SI-altered. CP: 0.3%, PY-0.5%, MO:0.01%. BRECCIA - Intrusive (?). MG-BI-altered. QZ veins. CP:0.1%, PY:0.1-0.3%. ANDESITE. MG-aLtered. QZ-GY veins. Localized MS-SI-alteration. ANDESITE. MG-altered. QZveins. CP: 0.1-1%, PY: 0.3-1%, MO: 0.01-0.03%. DIORITE. MG-altered. QZ veins. PY: 0.5-1%, MO: 0.03%. FELDSPAR PORPHYRY. MS-CL-altered. PY:3-4%. DIORITE. MG-altered. QZveins. PY:0.5-1%, CP:0.3%, MO:0.01%. ANDESITE. MG-CL-altered. QZveins. PY: 0.3-0.5%, CP: 0.05-0.1%. EOH -  200  I  0)  C))  05  o  0  (31  01  0)  01  01  1%)  (51  C  r’,)  01  -  O  01  -J  -  .  ()  (11  -  CD  .  C  .  C) 01  01  C’)  C) C  L)  o o  01  C  .11.  C  C’)  C  C’)  C  -  C  C’)  0  -  0  C  C  C  3()  00000C00000  0)  ()  C  01  0)  -  z.  N  >  -.  2. CD  0 0)  corn  0 C)  I I I  P  ox  nm  -<  C  m Q  0—I Co o -In  ,I  4  4 ,a  Project: Taseko From  To  0.00  9.30_Casing  Hole Number:  O8TSK-06  Rock-type & Description 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  ,7 —  less porphyritic. Weak QZ-CP-PY (trace BO) veining, typically 10 mm wide, locally with MO. Localized MS-CL.PY alteration as vein selvages. Fracture-coating CP-PY.MG.MO.  /17.5/;  ,,1  a Pervasive throughout matrix Biotite 2.50*5 a Pervasive throughout matrix  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> <@ 12.45 PY Vein 65.00° 1.00mm>  15 -  <@ 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  Project: Taseko From  To  Hole Number: O8TSK-06 >  Rock-type & Descript Ion  From 5  050  <@ 16.30 QZ Vein 35.00° 3.00mm> @ 16.80 QZ-CP-MO Vein 50.00° 2.00mm>  3  0  0.  0  5  0  4  5  40  Width  Sample  CuMo  Au  1ii 32_ 21  %OSL  0  I, II  17.00  To  32.50_Diorite__________  ILSQ_ 1J.30_ 40_  G0811578  %Z3L  Porphyritic diorite, same as above. Good core competency. Oscillatory-zoned FP  18.30  IL3Q_  100 ZL 8ZL G0811580 .Q0  phenocrysts (25%) typically —5 mm in size, up to 10 mm. Alteration gives the  1.&30  19.3L  I0Q_  G0811581  755_  24_  %SIL  phenocrysts fuzzy edges. Patchy BI-MG alteration. MS strongly developed as  19.3Q  21L3L IOL  G0811582  1ll7Q_  43_  O.OIL  large selvages to QZ veins. Moderate, pervasive CL alteration. PY-CP..trace MO  20.30  2j.3Q_ iSL  G0811583  73L_ St_  on fractures and as veinlets. Sub.rounded clast of CL-altered, equigranular  213Q  G0811554  ‘1.3Q  22.30_ jOQ_ 22.3Q_ tOO—  22.3Q  23.30_ iQL  G0811586  24.3Q  L tOO- 08i1SL 4O- 3L 44 26.3L jQO- G0811588 1310_ 52_ Q.OZL  I,  quartz monzonite (81-MG alteration absent).  “4 ‘4  7 /7  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 °  ‘4  20  G0811585 1520_  5L_  ‘I.Q3L  25.30  26.30  iOQ_  G0811589  1340_  26.30  aZ.3L tOO-  G0811590  692_ 202__ Q.OL  // “4  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  17.00- 25.00 Molybdenite 0.10%s a Molybdenite 0.20%aa Pervasively replaces  //  0.20%a a 27.00- 30.80 Chalcopynte 0.75%a a 30.80- 32.50 Chalcopyrite  1.00%a  ‘iL ZZL_ IL_ %21Z  /74  —  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  </  18Q  ‘4-  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  1L3Q  ‘7% /\j  G0811594  30.3Q  3tL jOQ_  31.30  32L tOO- 081i9L 889  255_  1O25_ 2O5_ 36  %04L  01019 Q2  7%  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°>  /7%  <  “4‘  I,  <@ 18.80 QZ-CP-PY Vein 12.00° 1.00mm> <t 19.10 QZ-FP-CP Vein 60.00° 8.00mm>  //44  <@ 19.10 PY.QZ Vein 60.00° 1.00mm> <@ 19.25 CP-PY Fracture >  /.,%44  <@ 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>  25  —  //  ‘4-  ‘7— “4  04  “7%“4,  <I 24.20 PY-CP Fracture 15.00°> 2008111/03  Equity Exploration Consultants Ltd.  ‘graphic log not to scale  Page 2 of 13  Project: Taseko From @ <c @ @  To  Hole Number: O8TSK-06  Rock-type &  24.50 QZ-PY Vein 12.00° 5.00mm> 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  a On fractures, in veins & disseminated Pyrite 2.00%>, a Disseminated & in  fractures Chalcopyrite 1.50%a <@ 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>  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  Hole Number: O8TSK-06 K  Rock-type & Description  0  selvages. PY, CP, and MO also as fracture coatings. Thin 02 veinlets often  5  0  40  40  4  0  5  0  it’  contain flakes of MO. Intense MS-CL indicative of phyUic alteration. I— 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  Width  40.30  41.30  tOO G0811606  1150_  II  4l.Q_ i.PP_  00811611  298L  13L  Q.1L  473L  48.3Q  1QP  00811612  1SQQ_  1  Q.072  48.3L  49L  00811613  260L  1Q QJSL  49.30_  50.3L  tQQ_ LOQ_  00811614  1515_  I  tOQ_  00811615  629_ L_ Q.02L  54.3Q_ 55.Q_ j9_ 5SQ  —  Chalcopyrite 1.25%aa 54.30- 57.30 Chalcopy rite 0.75%aa Molybdenite 1.00%a  I— ‘ //  <@ 36.60 QZ-MO-CP Vein 60.00° 5.00mm> <@37.10 CP-QZ Vein 35.00° 2.00mm>  189L  1fi__ 0.0Th  U85_  136_  73p  00811623  150L 1000  S4 0.0W 69 07 -34_ 9.0W  8.3Q  59.3p  jQ_  00811624  59.3L  1.00.  00811625  89.30_  60.30  j.0P_  00811626  1305_  80.30_ 1.30  tQO_  00811627  1I70_  3s  L00_  00811628  955_  ZL_ QJII2.  62.3L  jj55_  S6.30_ L01L  00811632  86Q  L3Q  100  <@ 38.70 EP Fracture 30.00°> <@ 40.67 QZ-PY-CP Vein 70.00° 4.00mm>  87.30_  6531  1.OQ_  G0811403 00811634  <@ 42.96 QZ-CP-PY-MO Vein 40.00° 4.00mm> <c 46.80 QZ-GL-MO-CP-PY Vein 50.00° 4.00mm>  89.30_  70.30  j.gQ_  00511636  127  10.30_  72.30  2.QQ_  00811637  107L  <@ 48.10 QZ-KF Vein 80.00° 3.00mm> <@ 48.16 MU-CP-PY Fracture 85.00°>  12.30_ 73.30  jflQ_  00811638  1575_  7A30  LQ0  830 53Q IQQ  //  13.30 —  <@ 51.60 PY-MS Fracture 75.00°> 2008111103  Equity Exploration Consultants Ltd.  m  8.3Q_  8S.3L  ,  55  Q,042  5Z30 6130 L00 08ii82L 1125 348 0.0II 08ii8Th 1S 8 83.3O 540 t00 9.0W 54.3L. S5.30_ t 00811631 841_ Th__ ‘I.008  so_  <@37.50 QZ-MU.CP Vein 30.00° 5.00mm> <@ 38.40 QZ-PY-CP-MO Vein 70.00° 15.00mm>  64.  G0811622  4t3L  <‘ I,—  15i0  1.QQ_ jgg  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  00811619  0Q P8iiS20 00811621 jQ  173L c&3g  86i0_  <@ 35.45 QZ-CP (MS-CL selvage) Vein 50.00° 6.00mm> <@36.40 QZ-PY Vein 80.00° 7.00mm>  55.30  5.Q_ 55jg  II  a 57.30- 66.50 Pyrite 1.00%a <57.30- 71.50 Chalcopyrite 0.30%sa 57.30-  <@ 49.80 QZ-PY-CP-MG Vein 70.00° 3.00mm> <@ 51.40 QZ-PY-CP Vein 50.00° 5.00mm>  1ø Q.008 65 Q1  S2.3L jQ_ 00811616 82L 184 Q.0Ii S2 530 IQQ 0811 1205 123 0.013 08IIS1L 959 98 54.3Q tOQ  0.30%aamo 0.10%aa 38.30- 42.40 Chalcopyrite 0.50%soemo 0.30%sa 42.40- 49.00  <@ 37.20 MU-QZ.CP-PY-MG Fracture 35.00°> <c 37.30 QZ-CP-MO Vein 65.00°’  ppm  Si3L I,  Veining 3.00’sa 35.40- 57.30 Pyrite 1.50%aa 35.40- 38.30 Chalcopyrite 40  Mo ppm  45.30_  SO.3L. 51.30  Chalcopyrite 0.75%sse 42.40- 54.30 Molybdenite 0.10%aa 49.00- 54.30  Cu ppm  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  I—  <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  S amp I e  42 43.3Q L00 048I80L 534  I—  length. Could be dykes although no chilled margins observed. 02 veining throughout diorite but not granodiorite.  To  4t30_ 42.30_ t0_  —  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  From 4  I °graphic log not to scale  1650_  00J8Th 1470  14.30_ 75.3Q  1.09_  0081183L 1350 00811640 112L  1i30_  7&3Q  j.0O_  00811641  15.3Q  Th00  0.7O  0081iS4 5410  1630_  j  9.0j3  2Q  Q.OIL  t17_ Q.015 29 q.019 135 9.005 34 35  0.ei 0JJ  l85 Q.0iI  SL_ 9.02_ ‘I& 9.02L 34 9.021 Page 4of13  Project: Taseko From  To  Hole Number: O8TSK-06  j  Rock-type & Description  <@52.10 QZ-MU-PY-MO Vein 150.00° 5.00mm> <@ 58.50 CL-MO-PY Siickenslide 70.00°> <@ 52.65 QZ-PY-MO (crust iform) Vein 65.00° 15.00mm> <@ 53.70 MG-CP-PY Fracture 70.00°>  From  050  <@ 51.80 QZ-MO-CP Vein 45.00° 4.00mm> <@ 52.10 QZ-MO-CP Vein 15.00° 4.00mm  LOG  50  40  40  405  0  To  Width  Sample  pm  po  4  I— I— “—‘I,  <@ 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>  5S 4 \  4  <@ 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>  I—  <@ 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>  I—  If  II  <@ 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>  I—  <@ 72.55 Massive QZ-CP Vein 40.00° 5.00mm> t) C  2008111103  Equity Exploration Consultants Ltd.  °graphic log not to scale  Page 5 of 13  Project: Taseko From  To  Hole Number: O8TSK-06  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. 80  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  <  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>  85  <@ 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.  *graphic log not to scale  Project: Taseko From  To  Hole Number: O8TSK-06  j  Rock-type & Description  From  —  50  in the coarse-grained granodiorite.  0.50  50  40  °I°  5  110  0  To  —  —  Width  Sample  Cu ppm  Mo ppm  Au ppm  4  1/  a Chlorite 3.00°> e Sericite 2.00*s e Silicification 2.00°se Pyrite 0.50%> s I,—  Chalcopyrite 0.30%> a Molybdenite 0.01%>  I,—  <@ 86.80 QZ Vein 50.00° 10.00mm> <c 87.30 QZ-PY Vein 45.00° 4.00mm>  \‘r  9O  <@ 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  L  9L00_ 92.00_ 4.00_  G0811657  94S__ 458__ D.005  9200  93.0L i00  8I165L  114Q  unbrecciated grey diorite. Core competent GY on fractures. Matrix is  93.00_  94.Q0_ I00_  00811659  164Q_ Z41_ Q.015.  fine-grained QZ-Bl-MG. Clasts are typically sub-angular with sharp margins and  94.00_  94.00_ &0_  00811660  are comprised of:  94,40_  95.QQ_ j.Q0_  00811661  tl.91L_ 1Z4__ 0.00L  95.OIL  95.00_ i0fl_  G0811662  234Q_ 61___ Q.05Z_  (2) Grey, medium- to coarse-grained, porphyritic, Bl-Sl+!-MG -altered diorite  95.00_  97.00_ I.QQ_  00811663  (7-15% PF phenos, up to 15mm, squat, irregular margins)  97.00_  98.00_ I00_  00811664  1520_ Z26__ 0.052_ 1270_ IZI_ 0.02L  (3) Grey-green CL-altered granodiorite  97.00 98.0L 10G  (4) QZ vein fragments  98.00_  90.00_  99.00  100.00 1.00  Several generations of QZ-PY+i-CP veining with intensive MS+/-CL selvages.  100.00  Disseminated PY. Locally SI-altered (decrease in grain size and bleaching).  IQiQO  137.8 149.4 m: Decreased CP, CL replacing BI alteration, QZ-PY-MO vein cuts -  102.00  MO-QZ vein.  103.00 104.00  -  A  Dark grey to black, polymictic, matrix-supported breccia with intervals of -  (I) Black, fine.grained, Bl-MG-altered andesite (locally porphyritic)  Unit is variably magnetic dependent on abundance of different clast.types.  a Quartz Veining 2.50°s  95  —  100.  los  00811666  79_  12305_0.092  lDt00 1.0Q_  ‘IOL_  102.0fl i00  08114S  6S4 09 0.0W  101.00 iQL_  G0811670  640._.  60__ 0.02_  404.00 iOQ_  (0811671  822  8L_ Q.O1L  105.00 iOQ_  (0811672  lOSft_ 25_ 0.0W  105.00105.00 iQ0 107.00 1.0fl_  Pyrite 0.75%> s Chalcopyrite 0.20%>  107.00  105.00 iQQ_  s 91.00- 149.40 Molybdenite 0.01%s  108.00109.00 i00 109.00 11D0 1Q  105.00 Biotite 3.00°>  >91.00-112.50 In clasts and matrix Magnetite 3.S0°os  140__  Q.0.14_  IIL_ Q.0.11  -  105.00  -  040 1IL 00811668  I00_  a 91.00 -97.70 Silicification 3.50*> s Chlorite 3.00°>> Sericite 3.50*s>  s 91.00  Q.014  G0811674  8S 1890_  11i Q.022 164_ Q.OIL  00811675  93L_  ISL_ Oi2L  Q8116ZL 1680 fl8111ZL 400  1S4 0.IOL 59 Qi4L  110.30  litSO iSQ_  00811678  a 97.70- 105.00 Chalcopyrite 0.10%>  fltSO  111.30 tS0  081107L l66S 40  a 97.70-112.50 Pyrite 0.30%>> Chlorite 2.00*> >97.70-124.40 As vein selvages Sericite 2.50*9  111.10  11410 iS0_  G0811680  198L  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  11tS0  120.30 tS0  081133 1335  ll0_  >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  2008111103  Equity Exploration Consultants Ltd.  \°  *grsphic log not to scale  2400._ 6Q.___ 0.074. 87___ 0075  138 0.011  3L 0.02 Psge 7 of 13  Project: Taseko From  To  Hole Number: O8TSK-06  Rock-type & Description  From 0  .112.50-127.40 Magnetite 2.00°.  30  ê  0  53  0  40  To  Width  Sample  Cu  119.30  12080  t50  G0811685  .115.00-127.40 Chlorite 2.00°e Pyrite 0.30%.  i20.50.  122.30  t6Q_  G08l1686  202L  . 116.00- 169.10 Chalcopyrite 0.10%.  i22.3 123.50  t6Q_  (08116S7  23.OL.  122.80  1.SQ  . 12740- 137.80 Magnetite 3.00°.. Silicificatlon  1.00°.  .127.40-159.10 Chlorite 1.00°.. Pyrite 0.10%. 137.80- 143.90 Silicification 2.00*.  120_  e 137.80- 159.10 Biotite 2.00°.. Magnetite 2.00*,  91.20 QZ Vein 10.00° 3.00mm>  <@ 94.00 PY-QZ Vein 80.00° 2.00mm> <@ 95.70 02 Vein 50.00° 5.00mm>  125 —  <@ 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> <@103.90 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> <@150.30 QZ-CP-MO (MO at margins) Vein 60.00° 80.00mm>  135  -  <@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>  0.Q34_  59.. Q.Q3L 206L.. 12. °.04L  130511559. 29Q9  liQ_ °40L  126.5k 128.30  (0R11690  186L  50__ °t.53L  140_ t5P_ 40_  G0811691  223L  00811692  165L  SL_ A.04L 54._ .Q41  L5Q_  00811693  255L  9L t05.L  132.5k 134.30  1.50_  00811694  1705  74  134.3  t50  0S11495 1320  25 0.52L  1354 137.30  tSL_  cosiiss& 1810..  5L 004L  137.3k 135.50  1.50_  00811697  135.S 140.30  tSL..  GQ51169&. 1495_ ISL_ fl04L  140.3k 141.50  1.50_  G0811699  14j.5 14140  0.OL  00811700  136.50  0.OSL  125 IIL_ 0.60L 145L  SL_ ft3SL  14340  L5Q  0Siil0L 1245  fl&  143.3 144.50  tSQ_  00811702  144L  SL_ ‘1.069..  144.5 14540  fl  146.3& 147.50  1-50—  00Mi260 00811704  1560 35 ‘1.048146L. 4L_ %055  44t5  \r. r  <@103.40 QZ-CP-PY Vein 60.00° 4.00mm>  C0811688  59_  Au  1.25.3k 126.50 LSL. 128.3 129.50 12S.5 j3j.3Q i3i3 132.50  s 149.40- 159.10 Sericite 2.00°. e Sillcificatlon 1.00°.. Molybdenite 0.03%.  <  125.30  Mo  O04L  146.35 147.80  t5Q_  00811705  142.8514940 149.35150.80 150.85 152.30 152.35 153.80  t50 160 t5Q_  051i70L t795 60 il5Z 1500-67_0.D84  1.50-  00811709  00811708  149j..  153.85 156.30  1.50_  00811710  155.35 156.80  1.50-  GOSII7II  St_ %DSL ‘1.0582580- 54__ Q.QSL 241L. IQL_ r5.OSL  155.55 158.30  UL  00911712  155L  2120- 5L_  54__ ‘1.088-  <@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> <@143.90 GY-QZ-PY-MO Vein 75.00° 2.00mm> 2008111103  150..  Equity Exploration Consultants Ltd.  L  °graphic log not to scale  Page 8of 13  Project: Taseko From  To  Hole Number: O8TSK-06  Rock-type & Description  From 0  <@146.10 GY (cutting QZ-PY) Vein 60.00° 2.00mm> <  147.10 QZ-PY Vein 50.00° 1.00mm>  50  \‘r  0  3  0  0.  0  To  —  Width  Sample  CuMo  Au  4  <@148.90 GY Fracture 50.00° 3.00mm> <l 151.87 MU-GY-PY Vein 70.00° 3.00mm> 155_  <@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 156.3C 156.50  t50  0S1Ili 45D  156.8l  151.30  1.SQ_  G0811714  316L.  ISL_ 0.12L  2SL  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  162  t5Q  284  154.30  tSQ_  GQSJI1IS 00811716  3510  162.5  3ZItL  1iL_ 0..ISL  164,3  156.46  tSQ_  G0811717  Z450_ 3L._ 0.IL_  165.54,  167.30  1.50_  00811718  247L.  167.34,  155.50  t5Q_  00811719  265L_ 8L_ 0.1SL  165.8k 17Q 1.70.34, 11180 171.54, 117.30  0 1.S0_ 1,50_  G051Il2 4610 G081i721 1600 00811722 299L  113.30.  114,46  tSQ_  00811723  1520_  12L_ Q.03L  174.50.  116.30  1.SQ_  00811724  1160  66  174.50.  116.46  t5L..  G0811725  <@167.30 QZ-PY-M0 Vein 85.00° 2.00mm>  176.30.  117.50  1.50_  00811726  1300_  14 0.325_  <@170.70 QZ-PY-M0 Vein 80.00° 8.00mm>  177.54,  118.46  110  G0811727  151L  44.L_ 0.02_  -  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. .4.5  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 170_  tv  <@164.10 QZ-PY-M0 Vein 60.00° 10.00mm>  <@172.10 QZ-MO-PY Vein 70.00° 12.00mm> < 171.30 QZ-PY-CP-M0 (margins) Vein 85.00° 20.00mm>  6.09L  SL_ 0.Q9_  160 6.20L 8Z 6.072_ 13L_ Q.032_ Q.01i  175_  <s 176.30 QZ-PY (MS selvaqe) Vein 70.00° 3.00mm> C  2008111103  Equity Exploration Consultants Ltd.  *graphic log not to scale  Page 9 of 13  Project: Taseko From  To  Hole Number:  O8TSK-06 —  Rock-type & Description  From 50  \cf  0  0.  0  00  0  40  40  0  ——  To  Width  Sample  Cu  Mo  Au ppm  4  <@177.50 QZ-PY (margins) Vein 60.00° 50.00mm <@178.90 Between Breccia Hydrothermal(?) and Andesite Contact 60.00°> -  178.90  I  214.00_Andesite  118.90  180.40 I.80  G0811728  1.440_  57__ 022  180.40  181.80 i.80_  G0811729  1140  4_ %OIL  flne.grained with <1 mm FP phenocrysts, SI-altered, and is moderately to  18.t90  G0811730  143.40 164.80  183.40 184.80 1660 187.40  I.80_  strongly magnetic. QZ veins with MU-MS or MS-CL-HE-EP selvages, PY+/-CP vein  i40_  G0811731  1290_ 32__ %OL_ 1180_. 2___ .02_  Black andesite with dykes of green-grey diorite, core competent. Andesite is  180  -  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. 190  a Magnetite 3.00°a a Silicification 7.00°sa Proximal to QZ veins Sericite 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>  \f  195_  \‘r  \  <@196.10 QZ FP-CP-PY Vein 70.00° 3.00mm> <@197.60 QZ-PY (CL selvage) Vein 65.00° 3.00mm>  200  <@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>  205_  1SQ 185.40 t80_ 167.60169.80 i.8 189.40 190.40 j.59_ 1SQ.40 182.30 i.50_ 192.30 193.40 tS0_  081il3 1059  89  G0811733  695_  1iL_ Q.OQS  08Ii14  2140 148  G0811735  889_  4L__ fl.81L  G0811736  1290_  S9___ %022  Q0811737  2018..  183.80  188.30 t80_  G0811738  1390_  1iL_ i.042. 140__ 0.828  195.30  196.80  ISIL_  G0811739  115Q_  104._ Q.024_  198.40 196.40 8.00_ 198.60198.80 i.80 198.40 199.80 t50_ 189.80 201.30 I.89_  G0811740  flAiL  Q81i24L 1090  8L  (20811742  lSiQ_  104_ °.04._  G0811743  2990_  114__ 0.843.  201.30 202.80 tS0_  G0811744  2470_  67___  201.30  202.40 t50_  G0811745  20280  0.008_  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 0014  206.80  210.40 i.5L_  (20811750  754_  57___  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  <@210.30 QZ-PY-MO Vein 70.00° 15.00mm>  1]  210_  214.00  219.50_Diorite  I  214.60 216.20 i.80_ 216.30217.80 180  I,  Coarse-grained, porphyritic diorite with small (up to 25 mm), sub-angular  (20811754 540 081I25L 878  84__ 0.OOL 91  -a 1  2008111103  Equity Exploration Consultants Ltd.  *graphic log nottoscale  Page  0.0Th  Project: Taseko From  To  Hole Number: O8TSK-06  Rock-type & Description  xenoliths of andesite. —30% FP phenocrysts, obscured by alteration  From -  mottled  00  II—  appearance. Diorite is CL-altered with minor MG-alteration; CL after MG(?) an 5  —  BI. Where alteration Is strongest only 10% PF phenos seen. QZ+1-PY veins.  5045  4  0  40  5  0  4  Cu ppm  To  Width  Sample  217.80  218.80  1.00  G0811756  lasso>  ,lconn  inn  flnei 4757  145 nfl  III lfl  I Cfl  Ill Ifl  I2’2 Sn  a en  SAC  I’> en  11421%  ICn  laIn  Mo ppm  Au ppm  483  66  <0005  ifl,n  Ce  fl file  024  CA  fl file  SC  n nie  II \/ I,— /7 ,//  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%>>  7/—  <@215.90 QZ-PY-CL Vein 40.00° 5.00mm>  7/  <@216.70 QZ-PY (margins) Vein 70.00° 10.00mm> <@218.90 QZ-GY Vein 90.00° 2.00mm>  /7%,  <@219.50 Between Diorite and ANDS; sharp, planar Contact 40.00°> 7/  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  L  094 In  Magnetite 3.00°seln areas of Intense veining Chlorite 3.00°oe Quartz Veining  227.30  228.80  225_  3.00°s  1.50  G0811763  1640  194  0.026  1.50  G0811764  1480  65  0.036  G0811765  228.80  230.30  1.50  <@222.26 QZ-PY Vein 90.00° 15.00mm>  230.30  231.80  1.50  G0811766  1080  39  0.031  <@222.87 QZ-PY-CL (centre-fill) Vein 60.00° 10.00mm> <@225.00 QZ-PY Vein 80.00° 2.00mm>  231.80  233.30  1.50  G0811767  826  38  0.015  233.30  234.80  1.50  G081176a  1820  79  0.04  348G  3S30  60___ 0.021  <@228.30 QZ-PY-MO.AC Vein 70.00° 10.00mm>  230_  <@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_  G0811769  l0ZQ_  L50  GQSIiIZ0.  12Z0  t30  00511271  Black, fine-grained andesite with fine-gralned squat FP phenocrysts. Core  22140230.30  competent MG+I-Bl-altered. QZ+I-PY veins with bleached CL selvages, core  230.30  30Q.0Q  fractures along veins. Veined core has pseudo-brecciated appearance.  240.80  ‘AZ0  Interstitial PY and trace CP.  2420 45Q 240_  ii  243.40  Magnetite 3.00°s Chlorite 2.00*ss 235.00- 241.60 Pyrite 0.30%ss 241.60-  247.70- 256.50 Chatcopyrite 0.50%ssmo 0.03%s <@236.87 QZ Vein 70.00° 20.00mm> 2008/11/03  245_  Equity Exploration Consultants Ltd.  *graphic log not to scale  00 1Q  Z2 Q.03  180  00301271  1260  Th 0.011  40  30fl7 G0811775  130 47 Q17 1420_ 143_ QJt22  G0811776  t470_  246.30 240.80240.30 245.30246.30 240.40 ‘.6130  tSQ_ t3 t50 L3Q_  00301271 W90 00311771 410  243.40  tS3._  (30811780  241.30  0.021  00511121  4L30 111  240.30  256.50 Pyrite 0.50%o*i 235.00- 247.70 Chalcopynte 0.10%ss Molybdenite 0.01%s*i  4—  tSQ_  230.30 23L8Q  (30811779  ‘.510_  5L__ 0.021 -  -o2  %11 0.021  Z_._ Q.031  Page 11 of 13  Project: Taseko From  To  Hole Number: O8TSK-06  j  Rock-type & Description  1  <@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> 250_  <@246.85 QZ-GY-PY Vein 80.00° 6.00mm>  From S  )O  5  0  4  0  4  5  5  5  0  4  To  Width  Sample  ,Upm  pn  i  25130  25250  2340  74  28Z50  18  4L  254.30  54ft t50 08ii782 255.5 j5Q_ G0811783  0837  454L  4L_ 0.022  26&80  26680  tOO  1105  222  0.012  255.80  256.80  1.00  25680  258.30  1.50  25830  25980  150  25850  25130  Ian  Rl 38  ean  Ian  an  254 38  264.30 265.80  <@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°> 255_  264.90_Diorite  256.50  I  Diorite with intervals of andesite. Gradational contact. Diorite is locally  // l//  porphyritic with FP phenocrysts up to 7 mm. Both are MG-Bi-altered; alteration  I,—  locally obscures porphyritic texture. Dense QZ veining QZ-MO veins with MO  II  -  at margins of veins (1  -  12 mm wide, typically 50-70 or 10 to core axis). 265_  ° Magnetite 1.00°sa 260.60- 264.90 Magnetite 300*aa Pyrite  // ‘I/f //  0.50%sa Molybdenite 0.03%s <@260.14 QZ-MO (margins) Vein 65.00° 12.00mm>  /f—  <@261.80 QZ.MO (CL selvage) Vein 60.00° 4.00mm>  II ‘I/f f/i  264.90  //%‘l/f  269.80_Diorite  265-  f/i  Locally porphyrltic diorite with angular xenoliths of fine-gralned andesite. PF  //  phenocrysts are MS-altered. Weak MG alteration, overprinted by moderate CL  If  a  0009  17  nn1  1395  5-3  0815  LJUOI 1lo  lien  252  0 812  1 50  LU5II lag  4355  Ac  8  265.80  1.50  “°“1  632  67  <0005  267.30  1.50  702  51  <0005  25730  259R0  Z50  497  75  <A_nba  269.80  270.30  0.50  flflO4l  764  894  167  <0005  270.30  27t80  t50  noa78l  189  14  <0.005  271.50  273.80  2.00  ISO  7  <0.005  nie  \\j  f/i  of the saccharoidai-textured matrix. QZveinlng. Chlorite 2.00*),  ‘I/f  44  f/i  alteration, which obscures porphyritic texture In places. Pervasive alteration  a  \‘r  1250 579  GORI 1757  II ‘I\IJ I/i  Magnetite 1.OO*sa Pyrite 0.50%s  f/i  <@267.79 QZ-QZ -PY Fracture 65.00° 20.00mm>  // I/i  <@270.30 PY-CL Fracture 65.00°>  269.80  274.10_Feldspar Porphyry  I  Feldspar porphyry dyke, core competent. 25% FP and HB phenocrysts In a  1/ \\// 270 —  saccharoidal-textured matrix. Pervasive MS alteration. Ha are CL-altered. FP phenos strongly MS-altered. Up to 3% dIsseminated PY. Low density of QZ  \‘r  /)  veinlets (only several microveinlets). PY on fractures.  a  Pyrite 3.00%a  2008111103  a  Sericite 3.00°ss  a  Chlorite 3.00*s  Equity Exploration Consultants Ltd.  °graphic log not to scale  Page 12 of 13  Project: Taseko From  To  Hole Number: O8TSK-06  Rock-type & Description  From 5  555  274.10  278.40_Diorite  50  5  5  5  45  4  0  I 275...  pervasive CL-alteration, Imparts green hue to core, Intense QZ-CP-PY+I.MO  Width  Sample  1.00  0811797  291  16  <0.005  G0811798  634__  74__  <0,995  pm  Om  pi  273.80  274.80  274.8  276.30 I40_  35_ <0.005 276.3k 277.25 I.95_ G0811799 77L zz azzo o i0L 429. 4 ZZL8 279.40 Q.9L 05iIQL 95L  Coarse-grained, porphyritic diorite. Core competency Is moderate; some core loss. Angular xenoliths of black, altered, fine-grained andesite. Intense,  To  4  ‘9 -.,1’  veining.  e Pyrite 0.50%s e Chalcopyrite 0.30%s a Molybdenite 0.01%s I— <@278.26 MIlky QZ-CL-CP-PY Vein 30.0r 6.00mm> <@278.40 PY-coated Fracture 56.00>  27L40_304.80_Andesite  ‘9—  I  275.4e 279.00 I.50_  G0811802  789  27  281.40 1.SL  (30811803  1.248_  35 mm). Larger QZ veins have MO in centre as fine stnngers. Coarse CP and PT  25Z,9  284.40 i8L  Q8iI4Q4 85L  interstitial in areas where veining creates brecciated texture. CL-alteration  282.9k 284A 285.0 2L4  Black, fine-grained andesite. Core competent Intense QZ.PY-CP.MO veining (1  -  280_  42____ 0.005 6L__ 0.01_ 57_ 0.996.  0.30%ea 287.30- 292.00 Pyrlte 0.50%s** 292.00- 304.80 Pynte 0.01 %ao  284.40 284.90 287.40 284.90 286.0 309,40  278.40-292.00 Chalcopyrlte 0.10%s a 287.30- 292.00 Molybdenite 0.01%e  29.0.4c 291.90 iSQ_  G0811810  S8L  196.  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 295A 297.90 t59  98iI9i3 1384 Q81i8I4 59L  12L  9.943. 0.916. Q.91__  around intense veining. a Pervasive, patchy Magnetite 3.00*55 Chlorite 2.00*50 278.40- 287.30 Pyrite  <@283.10 QZ-CP-MO (margins) Vein 70.00* 27.00mm> <@284.90 QZ-MO (centre) Vein 55.00* 55.00mm>  \  290,.,  <@287.90 QZ-CP-MO Vein 70.00* 40.00mm> <@290.60 QZ (CL selvage) Vein 30.00> <@295.20 QZ Vein 80.00* 5.00mm> <@298.30 QZ-MO Vein 50.00* 30.00mm> 295_  i.8Q_ G0811805 iSL 08U80L l57 I.80_ G0811807 1315_ I8Q 08fl80L 90 G0811809 825__ j.99.  29L  93_ 9.0D  IZZ_ 0.995  297.90 299.40 I.SL  G0811815  744_  74_  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  350_  2008111103  nxn PflH  I  Equity Exploration Consultants Ltd.  *graphiclognottoscale  9.005  209.40 399.90 i.8Q_  \  naxn  0.906.  12t__ 0.916.  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 Pb ages. 206 Pb/ individual calculated 207  216  °Ar 39 Table A.2 4 Ar geochronological dataset -  Laser Power(%) 1  40 A 9 Arfl r  Isotope Ratios Ar 39 ArI 37 38 Ar 39 ArI  36 A 9 Arfl r  CaIK  CIIK  40 atm % Ar  f 39 Ar  ArK 39 OAr*I  Age ± 2a  0.905  0.014  101.41  0.06  -8.052±9.881  -152.39±195.13  0.6  0.011  99.09  0.52  0.578 1.250  10.46 22.56  O6LH-HUB-36 Biotite -  J  =  0.010060±0.0000022; volume 39 ArK =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 2.3 66.857 0.008 0.102 0.025 0.035 0.063 0.224 0.020 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  0.008  2.6  9.04  4.540 0.022  80.57 0.38 80.91  3.4  4.718 0.004  0.047 0.012  0.008 0.019  0.001 0.056  0.174  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  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  0.39 80.52 0.37 80.24 0.34  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  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; volume ArK=3426.14; 39 integrated age 77.86±0.23 Ma 2 121.408±0.010 0.114±0.059 0.096±0.049 0.410±0.019 21 .269 0.006 2.2 0.053 0.029 0.057 0.045 0.067 0.021  0.005  99.74  0.17  0.289±2.061  5.25±37.33  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  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  56.86 3.34 72.01 1.44  2.8  5.202 0.005 4.798 0.005 4.648 0.004 4.606 0.004 4.599 0.004 4.5890.004 4.5740.004 4.5900.004 4.6000.004  0.027 0.012  0.003 0.034  0.002 0.025  13.7  10.52  0.005 0.030 0.005 0.028 0.004 0.029 0.006 0.035 0.0040.033 0.0040.030 0.0050.023 0.0070.028  0.001 0.030 0.001 0.077 0.000 0.039 0.000 0.094 0.0000.070 0.0000.055 0.0000.085 0.0000.082  0.05 0.094 0.113 0.075 0.123 0.076 0.091 0.1 0.161  0.003  0.027 0.018 0.027 0.015 0.027 0.012 0.028 0.013 0.0280.012 0.0290.011 0.0300.015 0.0330.013  5.35 2.7 1.65 1.65 1.26 1.16 1.12 1.18  9.35 7.32 12.78 10.38 11.71 11.03 8.17 7.94  4.440 0.028 4.489 0.024 4.466 0.024 4.481 0.019 4.472 0.021 4.481 0.021 4.471 0.019 4.4840.020 4.4900.020  78.88 79.73 79.34 79.60 79.44 79.59 79.41 79.64 79.75  3 3.2 3.4 3.7 4 4.3 4.6 5 -a  1.558 1.082  0.003 0.003 0.003 0.003 0.003 0.004 0.004 0.004  0.49 0.42 0.41 0.34 0.37 0.36 0.34 0.35 0.35  Table A.2 40 Ar 39 Ar geochronological dataset -  O6LH-HUB-45 Hornblende -  J  =  0.010078±0.000004; volume ArK=177.82; 39 integrated age 2 85.305±0.012 0.188±0.068 0.121±0.066 2.3 20.165 0.005 0.047 0.046 0.110 0.033 2.6 41.478 0.009 0.053 0.039 0.165 0.018 2.8  11.706 0.009  3.1  =  69.17±2.21 Ma 0.279±0.030  1.139  0.028  95.39  1.17  3.826±2.299  0.056 0.033  2.207  0.005  80.12  5.91  3.885 0.551  69.28 9.65  0.129 0.018  3.687  0.003  91.23  15.47  3.591 0.657  64.14 11.54  26.306  0.002  63.87  12.29  4.152 0.270  73.96 4.72  14.13  0  38.95  25.63  3.8370.098  68.45 1.71  6.4240.009  0.6140.016  0.030 0.030 0.011 0.027  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  0.019 0.056  12.022  0.001  21.88  7.25  3.865 0.146  68.94 2.55  0.034 0.047  0.531 0.017 1.415 0.017  0.008 0.063  3.8  5.372 0.008 6.708 0.009  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  4.435  0.036  59.78  0.39  7.999±1.964  74.49±17.92  2.566  0.014  62.45  1.46  5.845 0.642  54.73 5.92  34.78  2.6  5.621 0.492  52.66 4.54  3.65  6.326 0.143  59.16 1.31  -  1.137 0.016  Hornblende  0.005270±0.000008; 39 volume =168.92; integrated age = 60.60 ± 0.54 Ma; Ark 2 27.6317±0.0157 0.1898±0.0738 1.4742±1.0901 0.0727±0.0906 2.2  17.7348 0.0100 0.0856 0.1190 0.8586 0.6236 0.0420 0.0519 9.8563 0.0084 0.0469 0.0601 0.8388 0.2018 0.0154 0.1067 9.2075 0.0061 0.0351 0.0576 1.2592 0.1900 0.0108 0.0423 9.6066 0.0079 0.0384 0.1062 1.2984 0.0913 0.0109 0.1002 10.45390.0110 0.04760.1194 1.25450.2152 0.01230.2173  2.507  0.007  3.767  0.004  24  3.884  0.005  25.59  5.1  6.670 0.328  62.33 3.01  3.753  0.007  23.23  2.91  7.1840.797  67.04 7.30  3.2  9.7256 0.0091  7.666  0.039  21.73  6.24  7.208 0.326  67.26 2.99  3.6  7.80580.0068  15.694  0.078  13.58  13.39  6.5490.194  61.22 1.78  3.8  7.0989 0.0052  18.021  0.077  7.93  26.34  6.436 0.056  60.18 0.52  4  19.047  0.07  4.49  30.51  6.394 0.054  4.2  6.7853 0.0052 7.2485 0.0114  16.436  0.057  5.68  5.68  6.324 0.337  59.79 0.50 59.15 3.10  5  8.50400.0166  14.007  0.066  7.6  1.74  6.2050.846  58.05 7.78  2.4 2.6 2.8 3  00  68.25±40.25  0.027 0.036 0.0180.046  O7LH-231-1 J  =  0.1865 0.0354 2.5585 0.0368 0.0100 0.1078 0.35160.0232 5.22300.0184 0.00680.0928 0.3484 0.0177 5.9932 0.0135 0.0051 0.0285 0.31 70 0.0127 6.3320 0.0135 0.0043 0.0318 0.2632 0.0168 5.4205 0.0331 0.0060 0.1826 0.3031 0.0840 4.61470.1285 0.01120.2510  Table A.2 40 Ar 39 Ar geochronological dataset -  O6LH-GO1 J  =  =  =  71.83 ± 1.32 Ma; 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  0.194±0.033  1.707  0.024  98.28  0.55  0.873±1.817  15.83±32.78  0.0270.060  0.511  0.01  86.15  2.95  1.0720.485  19.41 8.74 19.12 4.11  O6LH-039-1 J  Biotite  -  0.010093±0.0000062; 39 volume =244.4; integrated age Ark 80.602±0.009 0.152±0.045 0.212±0.029 2  -  Horn blende  0.010089±0.000004; 39 volume integrated age ArK=216.69; 56.072±0.016 2 0.197±0.051 0.154±0.091 2.3 8.7650.018 0.0460.050 0.0620.053  =  21.74 ± 0.96 Ma;  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  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  6.641  0.088  1.2700.259  22.97 4.65  9.623 0.006  0.819 0.012  0.689 0.014  16.169  0.185  63.53 87.36  4.57  3.2  0.011 0.077 0.031 0.024  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 CO 2 laser 2 T he 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 1 3 NPT 13 cm E  Table A2 U-Pb Laser Ablation geochronology dataset -  Sample number and rock type  O6LH-G02 (Northern Charlie dyke) Location: (4553353mE, 5669938mN)  O6LH-GO1 (Southern Charlie dyke) Location: (453136mE, 5669870mN)  Isotopic Compositions (Ia) Fraction  206 !Pb 207 pb  235 /U 207 Pb  238 !U 206 Pb  1  0.05384  0.08313  2  0.04847  0.07835  0.01138 0.0117  3 4  0.04595  0.0746  0.04582  5  Isotopic Ages (Ia) 206 IPb 207 Pb  235 !U 207 Pb  238 IU 206 Pb  364.3  81.1  72.9  122.5 0.1  76.6 73.1  75  0.01205  0.074  0.01201  0.1  72.5  77  0.04704  0.07472  0.01152  73.2  73.8  6  0.05137  0.08278  0.01222  50.9 257.3  78.3  7  0.05064  0.08221  0.01185  224.3  80.8 80.2  8  0.05132  0.08614  0.01218  255  83.9  78.1  9 10  0.04371  0.07306  0.01214  0.1  71.6  77.8  0.05245  0.0852  0.01219  305.2  83  78.1  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  77.2  75.9  1  0.04882  0.07931  0.01253  139.1  77.5  2  0.04956  0.0124 0.01257  174.5  82.9  80.3 79.4  205.5  84.5  80.5  90.5 82.5  80.8  3  0.05023  0.08503 0.08678  4  0.05464  0.09322  0.01262  5  0.04844  0.08467  0.01289  397.3 120.8  6  0.05267  0.09442  0.0127  314.4  91.6  81.3  7  0.05469  0.09656  0.0124  400.1  93.6  79.5  8  0.04575  0.081 58  0.01307  0.1  79.6  83.7  82.6  9  0.05273  0.08797  0.01254  317.3  85.6  10  0.0444  0.07909  0.01273  0.1  77.3  80.3 81.5  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 -  Sample number and rock type  O7LH-009 (Hub diorite) Location: (453430mE, 5668870mN)  O7LH-238 (Northwest Copper pluton) Location: (447595mE, 5670561mN)  Isotopic Compositions (Ia) Fraction  206 IPb 207 Pb  235 IU 207 Pb  238 IU 206 Pb  Isotopic Ages (Ia) 206 IPb 207 Pb  235 IU 207 Pb 77.3  238 !U 206 Pb  1  0.0477  0.0791  0.0119  83.5  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  0.0495  0.0871  0.0128  170.7  83.5 84.8  82.2  5 6  0.0475  0.0833  0.0128  75.9  81.2  81.9  7  0.0484  0.0863  0.0130  120  84  83  8  0.0476  0.0807  0.0125  79  78.8  80.2  9  0.0475  0.0842  0.0126  75.2  82.1  80.5  10  0.0477  0.0833  0.0129  80.9  81.3  82.5  11  0.0477  0.0836  0.0126  81.7  81.5  12  0.0491  0.0129  151.3  84.2  80.5 82.9  13  0.0479  0.0865 0.0815  0.0124  94.6  79.6  79.3  14  0.0480  0.0830  0.0126  98.7  80.5  15  0.0488  0.0898  0.0131  135.9  80.9 87.4  16  0.0479  0.0790  0.0124  92.1  77.2  83.8 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  81.8  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  6 7  0.0493  0.0625  0.0090  160.3  61.5  0.0541  0.0637  0.0087  373.7  62.7  58 55.7  8  0.0471  0.0585  0.0087  52.5  57.7  9 10  0.0476 0.0472 0.0469 0.0494 0.0468 0.0517 0.0498 0.0501  0.0590 0.0575 0.0592 0.0600 0.0569 0.0614 0.0678 0.0585  0.0089 0.0088 0.0091 0.0088 0.0088 0.0086 0.0097 0.0083  79.8 56.2 42.9 165.7 37.2 272.4 184.6 198.9  58.2 56.8 58.4 59.2 56.2 60.5 66.6 57.7  11 12 13 14 15 16  55.8 57  56.5 58.3 56.2 56.5 54.9 62.1 53.2  221  Table A2 U-Pb Laser Ablation geochronology dataset -  Sample number and rock type  O6LH-HUB-45 (Feldsparhornblende porphyry dykes) Location:  Isotopic Compositions (Ia) Fraction  206 IPb 207 Pb  235 /U 207 Pb  238 IU 206 Pb  Isotopic Ages (Ia) 206 IPb 207 Pb  235 IU 207 Pb  238 IU 206 Pb  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  87.5  0.04103  0.0759  0.013  690.5 0.1  117.4  5  74.3  83.3  6  0.04953  0.08263  0.01211  173.2  0.04378  0.07511  0.01285  0.1  80.6 73.5  77.6  7 8  0.0463  0.07788  0.01221  13.1  76.2  78.2  9 10  0.04934  0.08349  0.01227  163.9  81.4  78.6  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  79  0.04938  0.09163  89  82.6  14  0.0559 0.06152  0.09404  0.0129 0.01218  422.2 166.1  88.9  13  448.2  91.3  78.1  0.10034  0.0122  657.5  97.1  78.2  15  82.3  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 O7LH-225 O7LH-225 O7LH-225 07LH-225 O7LH-225 O7LH-225 O7LH-225 O7LH-225 O7LH-225 O7LH-225 O7LH-225 O7LH-225 O7LH-225 O7LH-225 O7LH-225 O7LH-225 O7LH-225 O7LH-225 O7LH-225  I I I 1 I I I I I 1 I 1 1 1 1 1 I I I 1  L-V L-V L-V L-V L-V L-V L-V L-V L-V L-V L-V L-V L-V L-V L-V L-V L-V L-V L-V L-V  -1.2 -0.9 -0.8 -0.4 -0.8 -1.1 -1.5 -1.3 -0.9 -1.2 -1.4 -1.3 -2.1 -0.4 -0.6 -0.3 -2.8 -0.7 -1.2 -0.1  154 128 131 136 128 132 154 129 109 154 163 147 140 150 154 149 1.63 143 145 152  2 1.4 1.46 0.2 1.4 1.3 2.47 2.24 1.43 2 2.78 2.2 4.5 0.86 0.98 0.18 2.78 5 2.1 0.16  O7LH-37-2 O7LH-37-2 O7LH-37-2 O7LH-37-2 O7LH-37-2 O7LH-37-2 O7LH-37-2 O7LH-37-2 O7LH-37-2 O7LH-37-2 O7LH-37-2 O7LH-37-2  I 1 1 1 1 I I 1 1 2 2 2  L-V L-V L-V L-V L-V L-V L-V L-V L-V L-V L-V L-V  -3 -2.9 -1.7 -2.8 -0.7 -4.5 -3.4 -2.9 -3 -2.7 -3.5 -2.3  190 193.4 180.2 180.6 110 187 188.1 183.2 188 180 183 178  10 10.1 5.6 7.2 5.5 7.05 7.7 7.4 7.5 5.7 5.6 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 O7LH-040 O7LH-040  I 2 2  L-V L-V L-V  -2.9 -4.5 -3.4  169 166 176  5 6.4 4.7  225  


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