Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Variation in hydrothermal muscovite and chlorite composition in the Highland Valley porphyry Cu-Mo district,… Alva Jimenez, Tatiana Romy 2011

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
24-ubc_2011_fall_alvajimenez_tatiana.pdf [ 112.31MB ]
Metadata
JSON: 24-1.0053171.json
JSON-LD: 24-1.0053171-ld.json
RDF/XML (Pretty): 24-1.0053171-rdf.xml
RDF/JSON: 24-1.0053171-rdf.json
Turtle: 24-1.0053171-turtle.txt
N-Triples: 24-1.0053171-rdf-ntriples.txt
Original Record: 24-1.0053171-source.json
Full Text
24-1.0053171-fulltext.txt
Citation
24-1.0053171.ris

Full Text

VARIATION IN HYDROTHERMAL MUSCOVITE AND CHLORITE COMPOSITION IN THE HIGHLAND VALLEY PORPHYRY Cu-Mo DISTRICT, BRITISH COLUMBIA, CANADA   by  Tatiana Romy Alva Jimenez  Geologist Universidad Nacional de Ingenieria, 2000  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 UNIVERSITY OF BRITISH COLUMBIA (Vancouver)  September, 2011  © Tatiana Romy Alva Jimenez, 2011  Abstract Muscovitic mica and chlorite are common alteration components in porphyry Cu-Mo deposits. Their mineral chemistry varies depending on the degree of fluid rock interaction, pressure and temperature and can therefore be used as alteration vector. At the Valley porphyry Cu-Mo deposit of the Highland Valley porphyry district, southern British Columbia, muscovitic mica forms part of the high-temperature K-silicate assemblage. It also forms in the adjacent Bethsaida Zone and the abandoned Alwin mine some 4 km to the west, where it is associated with quartz-sulfide veins. The host rock of these areas is granodiorite of the Bethsaida phase of the Guichon Creek batholith. In the Bethlehem deposits, fine- to medium-grained muscovitic mica and chlorite form parallel to fractures or disseminated in a more mafic host rock. The muscovitic mica forms as several textural varieties, including vein selvages where they replace the rock, replacement of igneous biotite and feldspar whereas chlorite replaces mostly biotite and amphibole. Muscovite in the core of the Valley deposit is sodium-bearing (ca. 0.6wt%Na2O, 0.8wt%MgO), but is more phengitic (ca. 0.2wt%Na2O, 1.29wt%MgO) at the Alwin mine and the Bethlehem deposits. Titanium, Li, Sn, V and Sr are present in higher concentrations in muscovites from the Valley deposit compared to those from other areas. In contrast Tl, Rb, Cs, B, Mn, Co and Zn concentrations are higher in muscovite from the Alwin mine, Bethsaida zone and Bethlehem than those from the Valley deposit. Major and trace element chemistry of muscovite reflects decreasing temperature and increasing pH from the central porphyry zones Valley to the peripheral hydrothermal systems. High concentrations of Cs, Rb and Tl in whole-rocks indicate extensive muscovite alteration, whereas high Li, Zn, Mn and Co relate to abundant hydrothermal chlorite in the whole rock. The variability in the chemistry of muscovite and chlorite is also detected using short-wave infrared spectra (SWIR). An absorption feature between 2200 nm to 2202 nm characterizes the Na-bearing muscovites from Valley, whereas more phengitic-muscovites from Alwin and Bethlehem deposits have an absorption feature between 2205 nm to 2209 nm. Mg-rich chlorites have an absorption feature at around 2341 nm, whereas the same feature shifts to 2350 nm for Fe-rich chlorites. Muscovite and chlorite chemistry varies laterally in porphyry Cu-Mo districts and is also reflected in SWIR spectra and whole rock geochemistry, techniques widely used in exploration.     ii   Table of Contents Abstract ..............................................................................................................ii Table of Contents ..............................................................................................iii List of Tables ....................................................................................................vii List of Figures ................................................................................................... ix Acknowledgements ......................................................................................... xiv Dedication ........................................................................................................ xvi Chapter 1: Introduction .................................................................................... 1 1.1 Porphyry copper deposits ................................................................................................ 1 1.2 Alteration in porphyry deposits…………………………………………………………2 1.3 Muscovite and chlorite in porphyry copper deposits……………………………………5 1.4 Objective of the project…………………………………………………………………7 1.4.1  Rationale.………………………………………………………………………………...7  1.5 Overview of the thesis…………………………………………………………………..8 1.6 Mineralogy and chemistry of muscovite and chlorite…………………………………..9 1.6.1  Muscovite………………………………………………………………………………...9  1.6.2  Chlorite………………………………………………………………………………….13     Chapter 2: Highland Valley porphyry copper-molybdenum district…......17 2.1 Introduction…………………………………………………………………………..17 2.2 Location……………………………………………………………………………...17 2.3 Exploration history…………………………………………………………………..21 2.4 Production in Highland Valley district………………………………………………21 2.5 Regional setting……………………………………………………………………...22 2.5.1  Host rock: The Guichon Creek Batholith ........................................................................22  2.6 Structural characteristics in the Highland Valley district……………………………25 2.7 Ore mineralization event in Highland Valley………..………………………………25     iii   2.8 Alteration in the Highland Valley district: Valley deposit, Alwin mine and Bethlehem deposits………………………………………………………………………………27 2.8.1  Silic alteration and quartz veinlet stockwork…………………………………………...27  2.8.2  Potassic alteration………………………………………………………………………27  2.8.3  Phyllic alteration………………………………………………………………………..30  2.8.4  Propylitic alteration……………………………………………………………………..31  2.8.5  Pervasive sericite and kaolinite…………………………………………………………32  2.8.6  Intermediate argillic alteration………………………………………………………….32  2.9 Other nonmetalic minerals in Highland Valley district……………………………...33 2.10 Metallic minerals and zoning at Highland Valley: Valley deposit, Bethsaida Zone and Bethlehem deposits…………………………………………………………………..34    Chapter 3: Alteration assemblages at Highland Valley as framework for hydrothermal muscovite and chlorite chemistry…………………………...38 3.1 Introduction…………………………………………………………………………..38 3.2 Samples………………………………………………………………………………38 3.3 Local setting: Highland Valley host rock……………………………………………39 3.4 Muscovite and chlorite textural classification……………………………………….41 3.4.1  Textural classification of muscovite……………………………………………………41  3.4.2  Textural classification of chlorites……………………………………………………...44  3.5 Alteration Assemblages.……………………………………………………………..47 3.5.1  Sodic calcic alteration…………………………………………………………………..47  3.5.2  K-feldspar and biotite alteration………………………………………………………..54  3.5.3  Phyllic alteration (muscovite - chlorite paragenesis)……….…………………………..56  3.5.4  Distal phyllic alteration………..………………………………………………………..61  3.5.5  Late clay alteration……………………………………………………………………...63  3.6 Discussion…………………………………………………………………………....65  Chapter 4: Variation of muscovite and chlorite in the Highland Valley district…………………………………………………………………………66 4.1 Introduction…………………………………………………………………………..66    iv   4.2 Methodology and sample preparation………………………………………………..67 4.2.1  Electron microprobe methodology……………………………………………………...67  4.2.2  Short wave infrared methodology (SWIR)……………………………………………...69  4.2.3  Laser ablation methodology…………………………………………………………….69  4.2.4  Whole rock geochemistry methodology………………………………………………...72  4.3 Muscovite and chlorite chemistry from electron microprobe analysis………………...73 4.3.1  Muscovite major element compositions…...……………………………………………73  4.3.2  Chlorite major element composition…..………………………………………………..83  4.4 Muscovite and chlorite microprobe analysis in comparison with SWIR analysis…….89 4.4.1  Electrom microprobe versus SWIR data - muscovite…………………………………..90  4.4.2  Electrom microprobe versus SWIR data - chlorite……………………………………..95  4.4.3  Discussion………………………………………..……………………………………..96  4.5 LA-ICP-MS analysis…………………………………………………………………97 4.5.1  LA-ICP-MS data………………………………………………………………………..97  4.5.2  LA-ICP-MS results in muscovite……………………………………………………….97  4.5.3  Trace elements analysis in muscovite - thin section technique ……………………….104  4.5.4  Discussion of LA-ICP-MS data for muscovites (Bethsaida phase - Bethlehem phase -  Guichon Variety)………………………………………………………………………………105 4.5.5  LA-ICP-MS results in chlorite………………………………………………………...108  4.5.6  Trace elements according to birefringence chlorite color of the Bethlehem phase and the  Guichon Variety…………………………………………………………………………..……111 4.5.7  Trace elements versus aluminum concentration in chlorite……...……………………114  4.5.8  Discussion of LA-ICP-MS data for chlorites (Bethlehem phase-Guichon Variety) ….115  4.6 Whole rock geochemistry at Highland Valley……………...………………………116 4.6.1  Compositional variability in host rock………………………………………………...116  4.6.2  Alteration influence on alkali element concentration…………………………………118  4.6.3  Comparison of LA-ICP-MS and whole rock geochemistry…………………………..119  4.6.4  Bethsaida phase, Bethlehem phase and Guichon Variety muscovite-chlorite comparison……………………………………………………………………………..123        v   Chapter 5: Conclusions.…………………………………………………….126 5.1 Muscovite chemistry………………………………………………………………….126 5.2 Chlorite chemistry……………………………………………………………………129 5.3 Implications of muscovite and chlorite chemical variations…………………………130 5.4 Exploration implications..……………………………………………………………132      References…………………………………………………………………...135    Appendices…………………………………………………………………..146 Appendix A1: XRD analysis in comparison with SWIR data for muscovites……………146 A1.1 Introduccion…………………………………………………………………………….146 A1.2 Methodology……………………………………………………………………………146 A1.3 Results…………………………………………………………………………………..146 A1.4 Examples………………………………………………………………………………..147  Appendix A2 : Petrographic hand sample description....................................................... 156 Appendix A3 : Electron microprobe analyses of muscovite and chlorite.......................... 162 Appendix A4 : LA-ICP-MS analyses of muscovite and chlorite....................................... 205 Appendix A5 : Whole rock geochemistry of selected samples of Highland Valley district………………………………………………………………………………...227 Appendix A6 : SWIR data of selected samples of Highland Valley district ..................... 232     vi   LIST OF TABLES  Table 1.1 General major and trace element substitutions in muscovite……………………..12 Table 1.2 General major and trace element substitutions in chlorite………………………..16 Table 2.1 Guichon Creek batholith phases and principal mineralogy description…………..24 Table 3.1 Textural muscovite definition based on grain size and place of occurrence……...42 Table 3.2 Chlorite birefringence colors and mineral replacement. Chorite occurrences from the Bethlehem phase, Guichon Variety and the Valley deposit….…………………………..45 Table 3.3 Detailed classification of assemblages of the studied transect Alwin-ValleyBethlehem................................................................................................................................49 Table 3.4 Muscovite textural types and corresponding alteration types…………………….65 Table 4.1 Detection limits values for electron microprobe analysis………………………...68 Table 4.2 Muscovite and chlorite parameters for formula standardization………………….68 Table 4.3 Principal trace elements that show a lateral variation in muscovite from the Bethlehem phase……………………………………………………………………………..99 Table 4.4 Principal trace elements that show good correlation or significative concentrations in the muscovite from Bethlehem phase and Guichon Variety………….............................102 Table 4.5 Principal trace elements that show good correlation or significative concentrations in the chlorite from Bethehem phase and Guichon Variety………………………………..109 Table 4.6 Comparative table of trace element concentrations in the muscovite versus whole rock geochemistry (WRG) from the transect Alwin-Valley-Bethlehem deposits.…………123 Table 4.7 Comparative table of trace element concentrations in muscovite and chlorite versus whole rock geochemistry (WRG) from Bethlehem phase and Guichon Variety……...…...124 Table A2.1 Hand sample petrographic description of selected samples. Transect (AlwinValley-Bethlehem)………………………………………………………………………….157 Table A2.2 Hand sample petrographic description – all data set…………………………..158 Table A3.1 Electron microprobe analyses of muscovite – Bethsaida phase……………….163 Table A3.2 Electron microprobe analyses of muscovite – Bethlehem phase and Guichon Variety………………………………………………………………………………………180 Table A3.3 Electron microprobe analyses of chlorite – Valley deposit……………………190     vii   Table A3.4 Electron microprobe analyses of chlorite – Bethlehem phase and Guichon Variety………………………………………………………………………………………193 Table A4.1 Error percentages based on average and standard deviation of analytical runs for limits of detection for GSE-1G standard……….…………………………………………..206 Table A4.2 LA-ICP-MS analyses of muscovite (grain-mount method)…………………...207 Table A4.3 LA-ICP-MS analyses of chlorite (grain-mount method)……………………...219 Table A4.4 LA-ICP-MS analyses of muscovite (thin-section method)…………………....224 Table A4.5 LA-ICP-MS analyses of chlorite (thin-section method)………………………226 Table A5.1 Upper and lower detection limits (LOD) for geochemistry (ALS Chemex method ME-MS61)………………………………………………………………………………….227 Table A5.2 Whole rock geochemistry from the transect Alwin-Valley-Bethlehem……….228 Table A6.1 SWIR data from selected samples of the transect Alwin-Valley-Bethlehem…233     viii   LIST OF FIGURES  Figure 1.1 Flow path and alteration zoning diagram typical for porphyry deposits after Seedorff (2005)………………………………………………………………………………..4 Figure 1.2 Phase diagram for the system K2O-Al2O3-SiO2-H2O-KCl at P(H2O)=1kbar showing the boundaries of several alteration types according to temperature and Log (KCl+K+/mHCl+H+). Redrafted after Hemley and Jones (1964), Montoya and Hemley (1975), and Hemley et al., (1980), Seedorff et al., 2005 and Tosdal et al., (2009). B. Phase diagrams showing the effect of variable temperature from 150° to 700°C, pH and activity of Mg and K. Redrafted after Seedorff et al., 2005………………………………... ………………………..6 Figure 1.3 Ideal muscovite structure showing the package layer and cation arrangement (Redrafted after Deer et al., (2003)...…………………………………………………….......11 Figure 1.4 Chlorite structure shows t-o-t trioctahedral layers alternate with brucite layer. Redrafted after Deer et al., (2009)………………………………………………………...…15 Figure 2.1 Regional location map of Highland Valley District related to the Canadian Coordillera Intermontane Belt in the Quesnellia Terrane of British Columbia. After Monger and Price, 1979.……………………………............................................................................18 Figure 2.2 Geology of the Guichon Creek Batholith with the location of the major mineral deposits of Highland Valley District (modified after McMillan, 1976)..……………………19 Figure 2.3 Interpretative cross-section of the Guichon Creek batholith based on geology, gravity and mineral deposits studies by Ager et al., 1973; McMillan, 1976 (modified after Casselman et al., 1995) and expanded view.…………………………..…………………….20 Figure 2.4 Detailed geology of the Bethlehem area (modified after Briskey, 1981)..………26 Figure 2.5 Planar and cross section view of approximate distribution of epidote and secondary biotite in the Jersey orebody (Bethlehem deposit) and Cross section through the Jersey ore body shown in A. (Modified after Briskey, 1981)………………………………..29 Figure 2.6 Map distribution for green sericite and chlorite veins around the Valley deposit and the principal deposits at the center of the Guichon Creek batholith, also in the map the projection of batholith root zone to surface of Highland Valley. (Modified after Casselman et al., 1995).……………………………………………………………………………………..31 Figure 2.7 Mineralization in Highland Valley district………………………………………36 Figure 2.8 Metallic mineral distribution in the Jersey pit-Bethlehem deposits (specularite, pyrite, chalcopyrite and bornite) and vertical view of A (modified after Briskey 1981)……37 Figure 3.1 Sample location map transparent-colored according to the intrusive phase rock of the Guichon Creek batholith map and schematic cross-section…..…………...……………..40     ix   Figure 3.2 Photograph having the dominant host rock types from the studied transect across Highland Valley district (Alwin-Valley-Bethlehem). ……………………….........................41 Figure 3.3 Photomicrographs of the principal muscovite and chlorite textural types taken in cross-polarized light………………………………………………………………….……....46 Figure 3.4 Mineral assemblages and alteration phases from Alwin mine through the Valley deposit based on crosscutting and minerals associations done in this study and schematic mineral assemblage and alteration phases of the Bethlehem deposits base on this study and previous studies from Osatenko and Jones (1976), and Briskey (1981) …………………….50 Figure 3.5 Map showing alteration outline according to the samples considered for this study and schematic cross-section…………….…….……………………………………………...51 Figure 3.6 Sodic-calcic alteration type assemblages from Bethlehem phase, hand samples, cross-polarized and backscattered electron image photomicrograph…………………… ….52 Figure 3.7 K-feldspar and biotite alteration (potassic alteration), hand sample, crosspolarized light, plane-polarized light and backscattered electron image photomicrograph ...55 Figure 3.8 Distal veins from Highland Valley cross section Alwin-Bethsaida Zone-Valley deposit, hand sample photomicrograph.……………………………………………………..58 Figure 3.9 Representative samples of phyllic alteration, hand sample and cross-polarized light photomicrograph……………………………………………………………..………....59 Figure 3.10 Breccia sample (G192) from the Iona pit-Guichon Variety, plane- and crosspolarized light photomicrograph……..………………………………………………………60 Figure 3.11 Distal phyllic alteration around the Bethlehem deposits, hand samples and crosspolarized light photomicrograph ………...…………………………………………………..62 Figure 3.12 Clay minerals hand samples and cross-polarized light photomicrograph from the Bethsaida phase…………………………................................................................................64 Figure 4.1 Electron microprobe data – Na(pfu) versus Si(pfu) of muscovite altering the Bethaida phase……………………………………………………………………………….74 Figure 4.2 Electron microprobe data – Fe+Mg+Si (pfu) versus Al cation total (pfu) of muscovite from the Bethsaida phase…………………………………………………………76 Figure 4.3 Electron microprobe data – Fe(pfu) versus Mg (pfu) and Mg(pfu) versus Si(pfu) p of muscovite from the Bethsaida phase………………..…………………………………….77 Figure 4.4 Aerial photo with location map of samples from the Bethlehem phase and Guichon Variety according to alteration type ……………………………………………….79 Figure 4.5 Electron microprobe data – Na(pfu) versus Si(pfu), Fe+Mg+Si(pfu) versus Al cation total (pfu) and Fe(pfu) versus Mg (pfu) of muscovite from the Bethlehem phase and Guichon Variety……………………………………………………………………...............79     x   Figure 4.6 Major element variations in muscovite from Alwin, Valley and Bethlehem deposits (data are colored according to location)…………………………………...………..82 Figure 4.7 Electron microprobe data Mg(pfu) versus Fe(pfu) in chlorite from the Bethlehem phase and Guichon Variety shown according to alteration type,....….………………………85 Figure 4.8 Aerial photo showing Fe distribution in chlorite from Bethlehem and Guichon samples according to electron microprobe data…….………………………………………..86 Figure 4.9 Electron microprobe data – Mg/(Mg+Fe+Mn)(pfu) versus Alvi/(sum Oct)(pfu) of chlorite from the Bethlehem phase and Guichon Variety according to the alteration type……………………………………………………...……………….......……………….87 Figure 4.10 Electron microprobe data – Fe(pfu) versus Mg(pfu) from Bethlehem phase and Guichon Variety showing chlorite composition relative to the birefringence color ………...88 Figure 4.11 Probe data color coded by SWIR results for muscovite of the Bethsaida phase. Data colored according to 5 equal ranges in the 2200 nm wavelength absorption feature. Plots Na(pfu) versus Si(pfu), K(pfu) versus Si(pfu) and K+Na(pfu) versus Si(pfu)…….………...91 Figure 4.12 Probe data color coded by SWIR results for muscovite from the Bethlehem phase and Guichon Variety. Data colored according to 5 equal ranges in the 2200 nm wavelength absorption feature. Plots K+Na+2Ca (pfu) versus Al cation total and Na(pfu) versus Si(pfu)………………...………………………………………………………………93 Figure 4.13 SWIR comparison between muscovite from Bethsaida and the BethlehemGuichon rocks………………………………………………………………………………..94 Figure 4.14 Probe data color coded by SWIR results for chlorite from the Bethlehem phase and Guichon Variety. Data colored according to 5 equal ranges in the 2350 nm wavelength absorption feature. Plot Mg(pfu) versus Fe(pfu)……………….……………………………95 Figure 4.15 Trace element trend of muscovite in the Betshaida intrusive phase..…………100 Figure 4.16 Trace elements in muscovite from the Bethlehem phase and Guichon Variety rocks. All data correspond to muscovite of the phyllic alteration……………………...…..103 Figure 4.17 Trace element in three textural types of muscovite from sample HVD039 (Alwin mine)…………………………………………………………………….………………….105 Figure 4.18 Aerial photo showing summary of the trace elements in muscovite from the Bethsaida intrusive phase…………………………………………………………….…….107 Figure 4.19 Trace element in chlorite from the Bethlehem phase and Guichon Variety….110 Figure 4.20 Zinc versus Li trace elements in chlorite according to the birefringence color (samples from the Bethlehem phase and Guichon Variety). Plots Zn(ppm) versus Li(ppm) and Zn/Li(LA-ICP-MS) versus Fe/Mg average data of electron microprobe ……………..112 Figure 4.21 Trace elements concentrations of chlorite from sample BTA20 (Guichon Variety) according birefringence color…………………………………………………….113    xi   Figure 4.22 Examples of some trace elements in chlorite with respect to the aluminum content in the octahedral site. Plots Zn(ppm), Ba(ppm), Mo(ppm) and Cu(ppm) versus Al(vi)/(sum Oct)……………………………………………………………………………114 Figure 4.23 Geochemical variations showing compositional element groups in the Guichon Creek Batholith (cross-section Alwin-Valley-Bethlehem deposits). Plots Mg(wt%), Th(ppm), Y(ppm), P(ppm), Ti(wt%), V(ppm)……………………..…………………………………117 Figure 4.24 Molar ratio plot showing projected alkali composition diagram according to the host rock type in Highland Valley …………………………………………………………118 Figure 4.25 Muscovite versus whole rock trace element geochemistry from Bethsaida phase in ppm. Plots Rb, Cs, Tl, Li and V.……….………………………………………………...120 Figure 4.26 Muscovite and chlorite versus whole rock trace element geochemistry in ppm from Bethlehem phase and Guichon Variety (biotite rich granodiorite and hornblende rich granodiorite, respectively). Plots Zn, Co, Li, Mn, Cs, Th….……………………………….122 Figure 4.27 Muscovite versus whole rock trace element geochemistry in ppm from the Bethsaida phase, Bethlehem phase and Guichon Variety. Plots Th, Cs, Rb……..………...124 Figure 4.28 Chlorite versus whole rock trace element geochemistry in ppm from the Bethsaida phase (Valley deposit), Bethlehem phase and Guichon Variety. Plots V, Co and Cs……………………………………………………………………...……………………125 Figure 5.1 Schematic and comparative diagram showing the variability of muscovite chemistry cross section (Alwin-Valley-Bethlehem deposits)…..…………………………..133 Figure 5.2 Schematic and comparative diagram showing result of chlorite composition variability around the Bethlehem deposits………………………………………………….134 Figure A1.1 Comparative graph showing the relation of the ratio of depth at the minimum point of absorption feature between 1900 nm and 220 0nm measured using SWIR data and the mineral classification by XRD………………………………………………………….148 Figure A1.2: Sample HVA01 (gray area) from the Valley margin. Hand sample photo, crosspolarized photomicrograph, SWIR spectrum for muscovite and XRD spectra after glycol treatment……………………………………………………………………………………149 Figure A1.3: Sample HVA01 (creamy area) from the Valley margin. Hand sample photo, cross-polarized photomicrograph, SWIR spectrum for muscovite and XRD spectra after glycol treatment…………………………………………………………………………….150 Figure A1.4: Sample HVD06 (margin of the Valley deposit). Hand sample, cross-polarized photomicrograph, SWIR spectrum and XRD analysis……………………………………..151 Figure A1.5: BTA04 sample from the sodic-calcic area of Bethlehem phase. Hand sample, cross-polarized photomicrograph of the XRD area (point 1 in hand sample figure) and crosspolarized photomicrograph of the areas selected for microprobe analysis (point 2 in hand sample figure). SWIR spectrum…………………………………………………………….152     xii   Figure A1.6. XRD spectra of sample BTA04. XRD spectra after glycol treatment……….153 Figure A1.7: Sample G107 of the phyllic/sodic-calcic transition alteration of the Bethlehem phase. Hand sample, cross-polarized photomicrograph, parallel-polarized photomicrograph and SWIR spectrum of the absorption features at around 1900 nm and 2200 nm…………154 Figure A1.8: XRD spectrum of sample G107 and XRD spectrum after glycol treatment...155     xiii   ACKNOWLEDGMENTS  This thesis project is part of the MDRU Porphyry Footprint project. Teck provided financial support along with the National Sciences and Engineeing Research Council of Canada (NSERC). Highland Valley Copper provided access to the mine site. Additional financial support was received from Imperial Metals Inc., BHP Billiton, Barrick Gold Corp. Freeport McMoRan and Vale. An SEG and Geoscience BC grant are also acknowledged. Special thanks and gratitude are extended to my supervisor Richard Tosdal who, despite the distance, constantly communicated with me, and knew how to push me and guide me through this project. I also wish to thank Farhad Bouzari, Greg Dipple, Thomas Bissig, John Dilles and Scott Halley for their valuable comments, dedication, edits and suggestions. I also wish to acknowledge the MDRU staff: Craig Hart, Karie Smith, Manjit Dosanjh and Arne Toma for their administrative support and the full collaboration with this project. I would like to thank Mati Raudsepp for helping and teaching me in the use of the Electron Microbeam/X-Ray Diffraction Facility. Similarly to Alison Koleszar from the W. M. Keck Collaboratory for Plasma Spectrometry lab at OSU. But nothing could have been possible without the unconditional support of my family. A mis padres Mercedes y Alfonso: gracias por que ustedes son mi guia, mi ejemplo y mi fortaleza, y por que siempre me han apoyado sin dudarlo en todas las desiciones tomadas en mi vida. Madre, gracias porque lo sacrificas todo para ayudarnos. A mis hermanos Roxana y Alfonso: sus palabras de aliento me han servido de mucho siempre, ustedes son parte de mi fuerza, gracias por confiar en mi y por estar unidos siempre a pesar de la distacia. To my husband Thomas: Thanks for understanding me and supporting me in my career and thanks because you are a great partner and a wonderful father. To my daughter Kira: thanks baby for allowing Mami to go to school, you have been my big inspiration. A todos ustedes los quiero mucho!     xiv   To all my dear friends from Vancouver and Lima and those who migrated somewhere in the world searching for a new destination. Thank you guys, I could feel your energy and the voice of encouragement permanently. Thanks to my office mates Jaime, Alfonso, Razique, it was good to be the only women in the office sometimes, I felt happily spoiled by you guys when you prepared the coffee for me. Also thanks to my friends and colleagues from MDRU-UBC, Will, Moira, Leanne, Leif, Brendan, Jack, Jess, Betsy and Lizzy. It was a great experience to be a student again and meet nice people. And a VERY special thanks to all my good friends and family who were with me in the most difficult time of my life: Maria Bissig, Alejandra Medina (Ale, eres tan buena, muchas gracias por socorrerme con Kira), Nory (y el preciosin que viene en camino), Lukas, Sabine, Yanet and Kely, Rebeca and Abraham, Cesar and Paola (mas que primos, mis amigos!), Jaime, Santiago, Alfonso, Ayesha and Shawn, Esther, Karie (I will miss you guys, thanks for being there), Jarek, Luis, Murray, Karen B., Steffany L.B., also to my uncondicionals friends since 25 years ago: Catherine L., Mercy, Karina S. and Cecilia W., and to my most crazy friend in the world, Catherina A., and to my first boss that I had who is now my friend and guide Pilar Rodriguez.     xv      To my little Kira You will see, There won’t be more difficult obstacles in your life anymore, I love you!                    xvi   CHAPTER 1 Introduction  1.1 Porphyry copper deposits Porphyry copper deposits are one of the most important types of magmatic hydrothermal deposits, being the most predominant source of copper in the world and providing around three-quarters of the copper in the world and half of the molybdenum (Dilles et al., 2000; Sillitoe 2010). Porphyry Cu deposits are related spatially, temporally and genetically to hypabyssal dioritic to granitic plutons (Seedorff et al., 2005), which represent the “supply chambers” for magmas and fluids rich in metal, sulfur, acid and alkalis. These intrusions extend upward and focus the buoyantly rising hydrothermal fluid upward and outward through the system (Sillitoe, 2010). The systems have large tonnages but low to moderate ore grades; are emplaced generally at 1-4 km and locally deeper depths; have an overall fluid temperature evolution from high to low temperatures; and are characterized by stockwork- and breccia type-hosted ore. hydrothermal alteration.  All are characterized by large amounts of  Some deposits have undergone supergene enrichment. The  hydrothermal alteration, which is a metasomatic processes involving extensive fluid - hostrock interaction, is extensive and typically zoned on a deposit scale (Lowell and Guilbert, 1970; Seedorff et al., 2005), but also around veins and fractures. Recognition of alteration associated with formation of a porphyry Cu deposit is critical for both exploration and discovery of new deposits as well as the understanding of the physiochemical evolution of hydrothermal systems. This thesis focuses on one of the lesser understood aspects of these economically important hydrothermal systems, that is the variation in chemical compositions of white micas (principally muscovitic micas) and chlorites laterally from a porphyry Cu-Mo deposit. This study utilized quartz-sulfide veins with selvages of muscovite and/or chlorite to document the changes over a 10 km distance in the Highland Valley district of British Columbia that incorporates several hydrothermal systems as well as host rocks of slightly varying composition.     1   1.2. Alteration in porphyry copper deposits Alteration in porphyry copper deposits is zoned about the multiple intrusions that form the core of the deposit (Fig. 1.1).  The magmatic hydrothermal plume that rises  buoyantly forms potassic assemblages at high temperature in the vicinity of the porphyry intrusion. This high temperature assemblage is overprinted and overlain by phyllic (sericitic) and advanced argillic alteration at shallower depths as the rising magmatic hydrothermal fluid cools and becomes more acidic. Peripheral to the magmatic hydrothermal plume is thermally driven circulation of ambient fluids forming propylitic, and at higher temperature sodic and sodic-calcic alteration assemblages (Dilles et al., 2000; Seedorff et al., 2005; Sillitoe, 2010). Late during the evolution of the porphyry system, the ambient fluid interacts with the lower temperature and still rising magmatic hydrothermal fluid to form intermediate argillic alteration assemblages. These typical alteration assmeblages are not developed equally in all deposits. Seedorff et al. (2005) in Figure 1.1 shows the interaction of fluid path with the host rock in porphyry deposits and the range of alteration assemblages present in porphyry Cu deposits. Some salient features of these typical alteration assemblages are listed below. Potassic alteration is chemically produced by alkali exchange and dominates the higher temperature, deep and proximal part of porphyry systems (Seedorff et al., 2005). A typical assemblage is quartz, K-feldspar, biotite and/or anhydrite and magnetite (Gustafson and Hunt 1975). Biotite will dominate in more mafic silicate rich rocks, whereas K-feldspar will dominate where the rocks are relatively mafic poor. Phyllic alteration (sericitic) is produced by the hydrolytic reaction in which feldspar (K-felspar and plagioclase) alters to white mica and quartz (note that the term sericite is usually applied for fine-grained muscovite) at temperatures below 550°C (Seedorf et al., 2005). Phyllic alteration forms selvages that may vary from millimeter to meter scales along fractures and faults, commonly accompanied with sulfides and quartz (Gustafson and Hunt, 1975). The quartz-sulfide veins with selvages of muscovite ± chlorite have been referred to as “D-veins” using the classification of Gustafson and Hunt (1975). This type of vein    2   commonly forms late during the life of the porphyry hydrothermal system and more importantly from an exploration perspective can be distributed over several kilometers laterally and vertically from the porphyry Cu deposit core. For example, these veins are present up to around 10 km laterally at Butte, Montana (Rusk et al., 2008), and up to 3 km vertically at Yerington (Dilles, 1987). At Highland Valley, the focus of this study, quartzsulfide veins with selvages of muscovite and/or chlorite are present from the Valley pit through the low grade Bethsaida Zone to Alwin Mine, located as much as 4 km south west of the Valley deposits (see chapter 2). Propylitic alteration consists of weakly metasomatized rocks formed by the volatile addition such as CO2 and H2O from the circulating ambient fluid. It is confined to the flanks, distal sides and peripheral upper areas of a porphyry deposit (Seedorff et al., 2005). Characteristic mineral assemblages contain chlorite, epidote with stable relict of igneous Kfeldspar and Na-plagioclase (Dilles and Enaudi, 1992). Sodic and Sodic-calcic alteration is produced by alkalic chloride non-magmatic fluid at temperatures up to and greater than 400°C. This alteration reflects alkali metasomatism by addition of Na and Ca rich from the fluid to the alteration minerals and loss of K and Fe minerals through fluid migration. There is in essence a net gain of Na±Ca and loss of K±Fe (Dilles and Enaudi., 1992; Dilles and Proffett, 1995). The typical assemblage described in the literature for sodic-calcic alteration is sodium-rich plagioclase, actinolite and titanite as principal minerals, and epidote, chlorite, diopside and calcite being commonly present (Carten, 1986; Dilles and Enaudi, 1992). Intermediate argillic alteration is a weaker and lower temperature (~200°C) form of hydrolytic alteration that commonly has a component of both the acidic magmatic hydrothermal fluid and the external circulating ambient fluid (Sillitoe 1993, 2000; Arancibia and Clark, 1996). Kaolinite, illite, montmorillonite and smectite replace plagioclase and chlorite replaces igneous or hydrothermal mafic minerals (Seedorff et al., 2005). K-feldspar and sodium-rich plagioclase are generally stable in these environments.        3   Figure 1.1: Flow path and alteration zoning diagram typical for porphyry deposits after Seedorff (2005). A. Model shows potassic alteration is overlain by sericitic alteration. B. Advanced argillic alteration preferently in shallow levels in the system up to the paleosurface. C. Hydrolitic alteration enclosed within and extending upward above the potassic alteration. D. Sodic-calcic and potassic alteration located at depth in the center of the system.     4   1.3. Muscovite and chlorite in porphyry copper deposits The occurrence of “white mica” (general term for muscovite, phengite, paragonite, illite) and chlorite, in a particular set of alteration or in the “D-vein” type (explanation above) in a porphyry system, are a source of valuable information due to variable chemical composition in time, temperature and space. Their study and interpretation is a useful tool for deciphering processes involved in diagenesis, regional deformation or alteration in hydrothermal environments (Frey et al., 1980; Johson and Oliver, 1990; Gutierrez-Alonso and Nieto, 1996). The Composition of these minerals reflects the physiochemical environment of formation. In hydrothermal systems, chemical composition of white mica and chlorite is controlled by pressure (depth of formation), temperature, composition of protolith and fluid, pH and Eh (Parry et al., 1984; Guidotti, 1984; De Caritat et al., 1993). Chemical variations of white mica have been mostly identified in metamorphosed and volcanogenic massive sulfide (VMS) deposits (Abad et al., 2003; Takeshita et al., 2004; Jones et al., 2005 among others). Unfortunately theres is limited information for these minerals in porphyry copper deposits. White micas such as muscovite in hydrothermal ore deposits are stable at intermediate to high acidity. In porphyry copper systems, they typically are related to copperore zones, whereas iron-magnesium phengite micas are mostly associated with lower temperatures in the upper and outer sericitic alteration zones (John et al., 2010; Fig. 1.2A). In the experimental thermodynamic data of Helgeson et al., (1978), the stability field of muscovite at 1 kbar of pressure varies with temperature. In a diagram of log (aMg2+/a2H+) versus log (aK+/aH+), the field of stability of muscovite at 300°C is wider but decreases considerably with the increase of the temperature. At 600°C, muscovite stability totally disappears and the stability field of andalusite and K-feldspar increase considerably (Hemley and Jones, 1964; Montoya and Hemley, 1975; Hemley et al., 1980) (Fig. 1.2). In contrast at temperatures below 200°C, illite and other minerals such as kaolinite and chlorite are stable. Similarly, chlorite is stable from 150°C to 400°C but the stability field becomes smaller at 500°C (Fig. 1.2B). Equation 1.1 shows how muscovite stability is influenced by pH. In an acidic environment, aluminum-rich muscovite is stabilized by reaction progressing to the left. Conversely, in a neutral environment, an increase in SiO2, K+ or Fe+2 supply stabilizes Fe-Mg     5   rich phengite: Equation 1.1. K(Al)oct2AlSi3O10(OH)2 + 3Fe2+ + 2K+ +9SiO2 +6H2O ⇔ 3K(AlFe2+)oct(Si4)tetO10(OH)2 + 8H+  Similarly, chlorite occurs with a wide range of iron and magnesium substitutions. Equation 1.2 shows that Al-poor chlorite is stable under neutral conditions and high Mg and Fe, whereas Al-rich chlorite is stable under acid conditions (J.H. Dilles, 2010, pers. comm.). Equation 1.2. 2(Mg)5Al(AlSi3)O10(OH)8 + 12H+ = (Mg4Al)Al(Al2Si2)O10(OH)8 + 6Mg2+ + 4SiO2 + 10H2O  Figure 1.2: A. Phase diagram for the system K2O-Al2O3-SiO2-H2O-KCl at P(H2O)=1kbar showing the boundaries of several alteration types according to temperature and Log (KCl+K+/mHCl+H+). Redrafted after Hemley and Jones (1964), Montoya and Hemley (1975), and Hemley et al., (1980), Seedorff et al., 2005 and Tosdal et al., (2009). B. Phase diagrams showing the effect of variable temperature from 150° to 700°C, pH and activity of Mg and K. Redrafted after Seedorff et al., 2005.     6   1.4. Objective of the project This study has two principal goals: -  Identify the footprint of the hydrothermal alteration in the Highland Valley porphyry deposits, focusing on the textural and chemical lateral variation in muscovite and chlorite across the hydrothermally altered centers.  -  Establish a lateral exploration vector of major and trace elements in muscovite and chlorite using analytical laboratory work such as petrography, electron microprobe analysis (EMPA), XRD and laser ablation–inductively coupled plasma-mass spectrometry (LA-ICP-MS) and compare them with less time-consuming techniques widely used by exploration companies such as multi-element geochemistry and shortwave infrared analysis (SWIR).  This thesis project is part of a larger collaborative project title “Footprints of porphyry Cu deposits: Vectors to the hydrothermal center using mineral mapping and lithogeochemsitry”. The Footprint project is led by Richard M. Tosdal, Scott W. Halley and John H. Dilles and includes research sites at the Highland Valley district, the Yerington district (vertical zonation), both Cu-Mo systems, and the Red Chris Cu-Au porphyry district. The footprint project has as objective to generate vertical and horizontal hydrothermal zonation with the result of the chemical variation in major and trace elements in these three different deposits. The Footprint project was generated by Mineral Deposit Research Unit and Oregon State University in collaboration with the following companies: Teck Corporation, BHP Billiton, Barrick Gold, Freeport McMoRan, Imperial Metals, Vale Inco and the Canadian government NSERC-CRSNG. This thesis concentrated on alteration mineral chemistry and lateral zonation in the Highland Valley District. 1.4.1. Rationale The Highland Valley district, which is hosted in the calc-alkaline Triassic Guichon Creek batholith (McMillan, 1985), is located in south-central British Columbia, Canada. The    7   benefit of the Highland Valley district is the large lateral area of alteration with limited compositional variation of the host rock, which provides an excellent opportunity to examine the range of muscovite compositions associated with large scale hydrothermal alteration that constitutes mineralizing porphyry environments. 1.5. Overview of the thesis Petrography, scanning electron microscopy, electron microprobe analysis and laserablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) were combined to map the major and trace element variations in the hydrothermal chlorite and muscovite across the Highland Valley district. The results are presented in a series of traditional format chapters, following a brief outline of the fundamentals of muscovite and chlorite mineral chemistry. The chapters are as follows; Chapter 1, Introductory chapter with background information on the stoichiometry of muscovite and chlorite. Chapter 2, presents background geological information of the Highland Valley district, focusing on the Valley and the Bethlehem deposits. Chapter 3, represents a detailed petrographic analysis of 25 representative samples selected from 106 samples collected along a transect from the Alwin mine to Valley and the Bethlehem deposits. These representative samples have been studied by various geochemical techniques. Alteration assemblages and textural context for muscovite and chlorite were studied in detail. Chapter 4, presents the results of major and trace element characteristics of muscovite and chlorite using electron microprobe and LA-ICP-MS. These results are compared with data obtained through less time-consuming techniques such as whole rock geochemistry and short wave infrared spectroscopy (SWIR). Chapter 5, Conclusions and exploration implications.     8   1.6. Mineralogy and chemistry of muscovite and chlorite White mica refers to a group of light-colored phyllosilicate minerals such as muscovite, phengite, paragonite, margarite and celadonite (Parry, 1984). Chlorite is a mineral group with a layered structure, which in many respects resemble the micas. Sericite is a field term for fine-grained white mica, which in addition to muscovite may include pyrophyllite, paragonite or even phlogopite and occasionally illitic mica-like minerals and interlayered disordered micas with other sheet-structures such as montmorillonite, chlorite and vermiculite (Meyer and Hemley, 1967).  However, the textural term sericite will not be utilized for this thesis because a detailed textural classification and quantitative analysis of the minerals has been undertaken (see chapter 3 and chapter 4). Both white mica and chlorite are common minerals formed in a wide range of hydrothermal, igneous and metamorphic environments. Thus they have the potential to record gradients and changes in fluid chemistry within the environment of formation. Muscovite is the most common of the white micas and together with chlorite will be the focus of this chapter. 1.6.1.Muscovite Considered as the most common of the white micas, and compositionally related to feldspar, feldspathoids and quartz, muscovite is an aluminosilicate (Deer et al., 1992; Bailey, 1984) that is very common in K- and Al-rich metamorphic rocks such as phyllites, schists and gneisses.  Muscovite also occurs in silica-rich plutonic rocks such as granites and  pegmatites (Kerr, 1959) and K-silicate hydrothermal alteration (Deer et al., 2003). The physical properties of the muscovite are distinct and include pearl-transparent color, flaky shape and perfect (001) cleavage. It is also flexible, elastic and forms pseudohexagonal crystals. In thin section, muscovite is identified by its strong birefringence color and cleavage (Kerr, 1959). Muscovite is classified according to the occupancy and substitution in the structure to di-octahedral micas. Muscovite is also classified as “True mica” on the basis of the interlayer cation (Rieder, 1998), with K+ the common cation to balance the charge. The interlayer site is interconnected with a tetrahedral-octahedral-tetrahedral layer (t-o-t) or “2:1 layer” in which    9   aluminum (Al) substitute for ¼ silicon (Si) in the tetrahedral group (Bailey, 1984): Si4+ = Al3+ (tetrahedral) + K+ (interlayer) and the octahedral site is generally occupied by Al (Fig. 1.3). The “t-o-t” layer units are bonded together by relatively weak A-O bonds (A=interlayer cation, O=apical oxygen of the tetrahedral). Because K+ is a large monovalent cation, the A-O bonds are weak. This accounts for the perfect cleavage (001) and high flexiblility of muscovite. In contrast, if the interlayer site were occupied by a large divalent cation such as Ca+2, the A-O bond are stronger and less flexible, which is a typical characteristics of brittle micas, such as margarite (Deer et al., 2003). The structural accommodation in the ideal layered muscovite occurs and it depends on the stacking arrangement either because of the rotation between layers or the regular translations of layers (Deer et al., 2003). The principal polytypes in the muscovites are 2M1, 1M, 3T and 2M2, however the most common polytype is the 2M1 for muscovite. Polytypes occur when two polymorphs (ability of a mineral to crystallize with more than one type of structure) differ only in the stacking of identical, two-dimensional sheet or layers (Klein and Hurlbut, 1985). The ideal formula of muscovite and parameters proposed by Rieder et al.(1998) are as follows with values in per formula unit (p.f.u): KAl[6]2☐Al[4]Si3O10(OH)2 [4] [6]  Si = 3.0 – 3.1  Al = 1.9-2.0  K = 0.7 – 1.0, (ΣA ≥0.85) * [6]  R2+ /([6]R2+ + [6]R3+) < 0.25 **  [6]  Al / ([6]Al + [6]Fe3+) = 0.5-1.0  Al[4]Si3= tetrahedral layer cation * A= interlayer cation or “K site” ** R=octahedral layer cation or [6]Al site OH= anion site  Several major and trace element substitutions may occur in either the tetrahedral, octahedral or interlayer position in the structure of muscovite (Deer et al., 2003). These    10   substitutions are shown in Table 1.1 and explained in detail as chemistry is an important topic in the development of the thesis.  Figure 1.3: Ideal muscovite structure showing the package layer and cation arrangement. Redrafted after Deer et al., (2003)     11   Table 1.1. General major and trace element substitutions in muscovite  References: Bailey, 1984; Munoz, 1984; Guidotti, 1984; Deer et al., 1992; Dahl et al., 1993; Guidotti and Sassi, 1998; Deer et al., 2003; Rieder, 2001.     12   1.6.2. Chlorite Chlorite includes an extensive group of isostructural phyllosilicates with a high degree of isomorphous substitution found in several geological environments (Hey, 1954; De Caritat et al., 1993). Chlorite properties such as color, chemical composition or structural configuration vary due to cation substitution in the structure (Deer et al., 2009), which in turn can be caused by temperature, pressure and the bulk-rock composition (De Caritat et al., 1993; Zane et al., 1998). Chlorite analysis, mainly in low-grade metamorphic rocks, shows three parameters that influence compositional variations. These are: the Fe/Mg ratio, the extent of the Tschermak exchange (Table 1.2) and the di-octahedral substitution between Al3+ and Mg2+ producing one vacancy in the octahedral layer. Additionally the Fe/Mg ratio and the replacement of Si by Al affect chlorite color (Hey, 1954; Deer et al., 2009). Bulk composition is thought to be one of the main parameters responsible for chlorite chemical variation (Kranidiotis and MacLean, 1987; Zane et al., 1998; Deer et al., 2009). In the Los Azufres geothermal fields in Mexico, the Al[4] content in the tetrahedral site is strictly and positively correlated with temperature but the variation of Mg and Fe content is host-rock dependant (Cathelineau and Nieva, 1985). In a study comparing geothermal systems and hydrothermal ore deposits, Shikazono and Kawahata (1987) showed that in geothermal systems the Fe/Mg ratios of chlorite depend on the composition of the original rock, but in a hydrothermal environment related to the Cu-Pb-Zn vein type and Kuroko mineralization the Fe/Mg ratio is strongly controlled by the fluid composition. In a different study on chlorite from New Brunswick, Canada, Lentz et al. (1997) demonstrated that the Mn/(Mn+Fe+Mg) ratio reflect the whole rock Mn content. Principal physical properties in the chlorite group are: green, dark green to colorless, soft and cleavage parallel in one direction (Kerr, 1959). In thin section, chlorite pleochroism is typically weak but may be strong in iron-rich chlorite varieties. Chromian-chlorite with strongly pleochroic violet or pink and manganiferous clinochlore with intense bluish-green color have been also reported (Deer et al., 2009).     13   The structure of chlorite consists of a negatively charged “tetrahedral-octahedraltetrahedral” (t-o-t) or “talc-like layer”: Mg3Si3AlO10(OH)21- (hypothetical composition) and a positive charged interlayer also called “brucite-like layer” Mg2Al(OH)61+  (hypothetical  composition). Substitution of Al in the brucite-like layer generates a positive charge that balances the negative charge due to the Al substitution for Si in the talc-like layer (Deer et al., 2009) (Figure 1.4). Chlorite is subdivided into three sub-groups: dioctahedral, di-trioctahedral and trioctahedral (Bailey, 1980). Trioctahedral chlorite have 6 octahedral cations per O10(OH)8 and equivalent Al ions in the octahedral and tetrahedral layers. The trioctahedral chlorite is the most abundant natural chlorite in which Al content is the dominant octahedral ion (Bailey, 1980; Wiewióra and Weiss, 1990); Dioctahedral chlorite has less than 5 octahedral cations per O10(OH)8 in the “t-o-t” layer and interlayer (uncommon chlorites) (Deer et al., 2009). Di-Trioctahedral chlorite, is dioctahedral in the t-o-t layer but tri-octahedral in the interlayer sheet (uncommon chlorites) (Bailey, 1980). The formula of the chlorite can be expressed as follows by Brown and Bailey (1962), Foster (1962), Deer et al., (2009); values in atoms per formula unit (pfu): (R2+, R3+)6vi(Si4-xAlx)ivO10(OH)8 R2+= Mg, Fe2+(commonly), Zn, Ni, Mn R3+= Al, Fe, Cr Also: Ti4+, V3+, Cu2+ and Li+ (minor) (R2+,R3+)6 = octahedral site (Si4-xAlx)= tetrahedral site x=1-3; charge 28 Ideal formula: (Mg, Fe)6(Si,Al)4O10 (OH)8 Si= 2.30 – 3.39 pfu Fe/(Fe+Mg) = 0.01 – 0.96 Al (tot oct)= 6 pfu     14   Major cation components are Si, Al, Fe and Mg for the chlorite formula. Principal substitutions that stabilize the chlorite structure can occur in both layers (talc and brucite-like layers) and is explained in Table 1.2 in detail.  Figure 1.4: Chlorite structure shows t-o-t trioctahedral layers alternate with brucite layer. Redrafted after Deer et al., (2009)  Iron content in chlorites The percentage of Fe+2 and Fe+3 can be calculated using wet chemical analyses. However Walshe (1986) calculated the ferric ion (Fe+3) using electron microprobe analyses and thermodynamic parameters. Based on the iron analyses in chlorites, Cathelineau and Nieva (1985) supported the idea that the Fe3+ is generally low (less than 5% of the total Fe). Bayliss (1975) suggested that Fe+3 (ferric iron) is commonly an oxidation product of ferrous iron with a loss of hydrogen.   Fe3+ substitute with reduction of H2O and loss H2  Fe2+ (OH-)2 = Fe3+ (OOH) However, Foster (1962) suggested that Fe+3 has relevance in the structure of many  chlorites and suggested that Fe+3-rich chlorites were formed by alteration of the mineral by Fe3+-rich fluids and should not be interpreted as a secondary oxidation product.     15   Table 1.2. General major and trace element substitutions in chlorite  (1)  (1)  (1)  Chamosite is the ferroan equivalent of clinochlore, which together form a solid solution series (clinochloreferroan clinochlore-magnesian chamosite-chamosite). References: Smith et al., 1946; Foster, 1964; Bayliss, 1975; Bayley, 1980; Walshe, 1986; Wiewióra and Weiss, 1990; Gonzalez et al., 1991; De Caritat et al., 1993; Gonzalez Lopez et al. 1993; Deer et al., 2009.     16   CHAPTER 2  Highland Valley porphyry copper-molybdenum district   2.1. Introduction The alteration history of the porphyry Cu-Mo deposits and prospects in Highland Valley has been previously established (McMillan, 1976, 1985; Jones, 1975; Osatenko and Jones, 1976; Reed and Jambor, 1976; Briskey and Bellamy, 1976; Briskey, 1981; Casselman et al., 1995). This early work is briefly summarized in this chapter and provides the basis for the petrographic classification of the studied samples (Chapter 3) and the understanding of the chemical variation in muscovite and chlorite (Chapter 4) in a transect from the Alwin mine through the Valley deposit to the Bethlehem deposits.  2.2. Location The Highland Valley porphyry copper-molybdenum district is located 54 km southwest of Kamloops and 350 km northeast of Vancouver in south-central British Columbia, Canada. The district lies in the southern portion of the Quesnel Terrane, within the Intermontane Belt physiographic province (Figure 2.1). The district is hosted in the late Upper Triassic calc-alkaline Guichon Creek batholith and contains five major deposits (Valley, Lornex, Highmont, Bethlehem and JA; Figure 2.2), two smaller deposits Krain and South Seas north of the Bethlehem pits, as well as several small delineated deposits such as Ann Number 1 and Minex and small high-grade vein deposits, which include Alwin (called OK/Dekalb in the past), Snowstorm and Aberdeen (McMillan, 1976). The abandoned Alwin mine is located about 4 km southwest of the Valley pit. Spatially, the district occurs in an area of over 10 x10 km and to depth of over 1 km elevation differences (Figure 2.2; Figure 2.3A).     17   Figure 2.1: Regional location map of Highland Valley District related to the Canadian coordillera intermontane belt in the Quesnellia Terrane of British Columbia. After Monger and Price, 1979.     18   Figure 2.2: Geology of the Guichon Creek batholith with the location of the major mineral deposits of Highland Valley district (modified after McMillan, 1976).     19   Figure 2.3: A. Interpretative cross-section of the Guichon Creek batholith based on geology, gravity and mineral deposits studies by Ager et al., 1973; McMillan, 1976 (modified after Casselman et al., 1995). B. Expanded view of the square in A. Valley and Lornex are hosted dominantly in the Bethsaida phase, Alwin probably formed in a deeper part of the pluton compared to Bethlehem.     20   2.3. Exploration history Exploration of the Highland Valley district began around 1896 and focused on the mineralization at surface at Alwin (Casselman et al., 1995). In the early 1900s, the highgrade veins of the Snowstorm zone were discovered. In 1919, testing of the Iona pit at Bethlehem began (McMillan 1985; Casselman et al., 1995). In 1955, exploration intensity in the area increased. In 1964, the Lornex deposit was discovered and in 1966 a drill campaign at Highmont outlined the first orebody. The Valley Copper was discovered in 1967 and JA in 1971 (McMillan, 1985). Production at the Lornex mine began in 1972. It was not until 1982 that Valley Copper began production and became the most important mine in operation of the district. Production at the Bethlehem deposits started in 1962 with a low-grade but large tonnage operation under the ownership of Bethlehem Copper Corporation Ltd. The Bethlehem production came from their four orebodies deposit: Jersey, East Jersey, Huesties and Iona (Briskey, 1981). In 1980, the Bethlehem mines closed due to low copper prices (McMillan, 1985). The Highmont mine operated between 1980 and 1984 but closed due to low metal price. In 2005, the East pit of Highmont was re-started and became part of the Highland Valley Copper partnership (Witt, 2008). Current mining is focused in the Valley and Lornex pits.  2.4. Production in Highland Valley district Currently Highland Valley Copper operates the open pits Valley (principal producer), Lornex and Highmont in the district. These open pits are the largest copper mine in Canada (InfoMine, 2011). The Highland Valley Copper is a partnership of Teck Cominco (95%) and Highmont Mining Company (5%); Highmont Mining has Teck Cominco as a 50% shareholder effectively giving Teck Cominco a 97.5% interest in Highland Valley Copper (Highland Valley Copper technical report, 2008). Teck acquired 100% of Cominco in July 2001 (Teck, 2011). Total recorded copper and molybdenum production in Highland Valley between 1894 and 2010 has been 1,428 M tonnes with 5,181x103 tonnes of Cu, 83x103 tonnes of Mo, 9.5 tonnes of Au and 1,516 tonnes of Ag (Ministry of Energy and Mines, 2011). In 2009, total    21   reserve (proven and probable) of the Valley, Lornex and Highmont mine were 440 million tonnes at 0.354% Cu and 0.0077% Mo. Additional total resources (measured and inferred) of the Lornex and Highmont mine estimates 201.18 millions tonnes grading 0.279% Cu, 0.0136% Mo (data updated at Dec 31, 2009, information from Highland Valley Copper internal report). Alwin mine, developed as a high-grade vein deposit, is currently property of San Marco Resources. In 1980, a total production was 155,000 tonnes grading 1.54% Cu (San  Marco Resources, 2011). Past production from Bethlehem deposits since 1962 are combined total production of 105.87 million tonnes grading 0.4% Cu.  2.5. Regional setting The Highland Valley porphyry copper deposits are hosted in the late Upper Triassic calc-alkaline Guichon Creek batholith (McMillan, 1985). The batholith intruded and thermally metamorphosed the Carnian to Norian Nicola Group composed of basaltic to andesitic volcanic and volcaniclastic rocks (Casselman et al., 1995) that form part of the Quesnel Terrane. The Guichon Creek batholith is one of a series of plutons intruding the Upper Triassic island arc volcanic rocks of the Nicola group (Mortimer, 1986). All the principal deposits of Highland Valley occur in the central area of the Guichon Creek batholith. Deposits are related to the youngest intrusive phases of the batholith (McMillan, 1985) (Figure 2.2).  2.5.1. Host rock: The Guichon Creek batholith. The Guichon Creek batholith is a roughly concentrical multiphase pluton (Northcote, 1969) that extends approximately 20 km in width and 65 km in length (Figure 2.2). Gravity model and magnetic data (Ager et al., 1973) indicate that the intrusion has a pipe-like root zone under Highland Valley plunging 80° to the northeast, resulting in relatively shallow, flat-lying funnel-shaped body (Figure 2.3A). This early interpretation of a “mushroom   22   shaped” structure for the batholith was later confirmed using seismic and potential field analyses by Roy and Clowes (2000). Rocks at the border of the batholith are older and more mafic (medium-grained diorite and quartz diorite), whereas in the central part they are younger and more felsic (granodiorite to quartz-monzonite) (Casselman et al., 1995). Mortimer et al. (1990) reported a U-Pb zircon age of 210 Ma ± 3 Ma from biotite-hornblende granodiorite of the Guichon Variety of the Highland Valley phase. The Guichon Creek batholith is composed of several phases distinguished by compositional and textural criteria (Northcote, 1969; McMillan, 1976). Four phases and their varieties are recognized. From the border to the inner part, these are: the Border phase (also known as the Hybrid phase), the Highland Valley phase composed by Guichon and Chataway varieties, the Bethlehem phase, and the Bethsaida phase, which includes a textural variety referred to as the Skeena Variety (McMillan, 1985) (Table 2.1, Figure 2.3). The younger phases intrude the older phases. The contact between the Border phase and Highland Valley phase (older phases) is everywhere gradational, the Bethlehem and Bethsaida phases (younger phases) cut the older phases (McMillan, 1976). Northcote (1969) and McMillan (1976) among others describe the crystallization of the batholith. The Border and Highland Valley phases are the oldest phases, forming the outer part of a semiconcordant pluton emplaced into the Nicola – Cache Creek groups. The young Bethlehem phase intruded the Highland Valley and Border phases. The Bethsaida phase intruded the Bethlehem phase and forms dikes and small plugs in them (McMillan, 1976). On the margin, the Bethsaida phase includes the Skeena Variety. Late dacite porphyry dike swarms, trending north along the Guichon Creek batholith, intrude all phases of the batholith except the Chataway Variety and the Border phase (Figure 2.2) (McMillan, 1976; Briskey, 1981). To the north of the Highland Valley fault, the Bethlehem, South Seas, and Krain deposits are associated with a dike swarm (postBethlehem dikes) that has textural and chemical similarities to the Bethlehem intrusive phase. To the south of the Highland Valley fault, dikes intruding the Skeena Variety and the Bethsaida phase have similar textural and mineralogical characteristics to the Bethsaida phase and are likely related to the later (post-Skeena dikes) (McMillan, 1976; Briskey, 1981).     23   Breccia bodies occur as three forms. Intrusive breccias occurs along intrusive contacts, pipe breccia occurs locally with the north-trending swarm of porphyry dikes becoming part of the intrusive Highland Valley, Bethlehem and Bethsaida phases. Fault breccias are related to fault structures (Briskey, 1981). Sedimentary, volcanic and volcaniclastic rocks were deposited after the batholith was emplaced in the Jurassic (Ashcroft Formation), Cretaceous (Spences bridge Group) and Tertiary (Kamloops Group) (McMillan, 1967) (Figure 2.2).  Table 2.1: Guichon Creek batholith phases and principal mineralogy description.  References: Northcote, 1969; McMillan, 1976; Briskey, 1980.     24   2.6. Structural characteristics in the Highland Valley district Several sets of faults and fractures cross the Highland Valley district. The principal trend is northerly and is represented by the Lornex fault and the Guichon Creek fault that bound the batholith to the east (Figure 2.2). The Lornex fault is intersected by northwesterlytrending faults, the Skuhun Creek, Highland Valley and Barnes Creeks faults (Casselman et al., 1995) (Figure 2.2). The intersection of the Lornex fault with the Highland Valley fault truncates Valley Copper deposit to the west (Figure 2.2). Near the Lornex deposit, the fault dip varies from moderate to steep toward the west, whereas around Valley pit it dips steeply to the east (McMillan, 1976; Waldner et al., 1976). At Valley and Lornex deposits, the Lornex fault separates the Bethsaida phase on the west from the Bethlehem phase and Skeena Variety at the east. The principal structural trends are reflected in the veins and fractures within porphyry Cu-Mo deposits. The main faults are post-mineral and truncate the ore bodies (Casselman et al., 1995). At the Bethlehem deposits, the principal faults trend north and are concentrated in the east-central part of the Huestis pit, the west-central part of the Jersey pit (where it is called the Jersey fault), the east-central part of the East Jersey pit (also East Jersey faults) and in the central part of the Iona zone (Figure 2.4). All faults dip steeply to the west or are vertical Many of these faults cut the mineralized Bethlehem breccias (Briskey and Bellamy, 1976) and are thus post-mineralization.  2.7. Ore mineralization event in Highland Valley Mineralization in Highland Valley is hosted in veins, faults and breccias where the intensity of alteration is linked to the intensity of fracturing. Two mineralization events are identified. The oldest event followed emplacement of the Bethlehem phase and coincided with the intrusion of dikes and breccia pipe formation in the batholith. The Bethlehem deposits Krain and South Seas formed at this time. The second, younger mineralizing event, and the most important was the porphyry Cu-Mo mineralization that followed emplacement of the Bethsaida phase. The Valley, Lornex, Highmont, JA, and several other deposits formed at this time (Casselman et al., 1995).    25   Figure 2.4: Detailed geology of the Bethlehem area (modified after Briskey, 1981)     26   2.8. Alteration in the Highland Valley district: Valley deposit, Alwin mine and Bethlehem deposits Several types of alteration have been previously recognized in the Highland Valley District. They are: silicic, potassic, propylitic, phyllic, pervasive sericite and kaolinite and intermediate argillic alteration. These assemblages are briefly described in this chapter to provide context for the observations and slight modifications presented in Chapter 3.  2.8.1. Silicic alteration and quartz veinlet stockwork Pervasive quartz replacement of wall rock defines the silicic alteration assemblage of Casselman et al. (1995; see also McMillan, 1985). Abundant quartz veins are associated with the alteration. Two types are recognized, primarily in the Valley and Lornex pits (Osatenko and Jones 1976; Casselman et al., 1995): 1) quartz vuggy with envelopes of sericite and Kfeldspar (associated with mineralization) and 2) quartz fine- to medium-grained veins without selvages or sulfides (most abundant).  2.8.2. Potassic alteration In Highland Valley, potassic alteration is defined by hydrothermal biotite and potassium feldspar. The potassic alteration is well developed in all the deposits of the Highland Valley district, especially those located in the central part (Valley deposit, Bethlehem deposits) of the district and in the Highmont and JA orebodies (Casselman et al., 1995). At the Valley deposit, potassic alteration is common in the deeper levels and developed adjacent to the quartz veins (McMillan 1985). It is poorly mineralized (Casselman et al., 1995). There, K-feldspar is associated with hydrothermal muscovite. Secondary Kfeldspar occurs as fractured-controlled replacement of host rocks and more commonly is     27   disseminated or concentrated in selvages to quartz veinlets. Minor secondary biotite replaces primary biotite or forms thin veinlets (Osatenko and Jones, 1976). In contrast, at the Bethlehem deposits secondary biotite is the principal mineral that defines the potassic alteration. Hydrothermal potassium feldspar is less abundant. Major concentrations of secondary biotite form in the Jersey ore body where they are associated with the bornite-rich core zone at depth in the deposit (Figure 2.5). There, hydrothermal biotite is commonly replaced by chlorite. Secondary biotite is widespread near the breccias in the Iona pit and moderately developed in the Huestis pit (Briskey, 1981; Casselman et al., 1995). Secondary biotite replaces primary biotite, hornblende, some actinolite and the breccia matrix (Briskey, 1981). It also forms veinlets and fracture coatings. Secondary biotite is mostly associated with chlorite, bornite and chalcopyrite (Briskey and Bellami, 1976).     28   Figure 2.5: A. Planar view of approximate distribution of epidote and secondary biotite in the Jersey orebody (Bethlehem deposits). B. Cross section through the Jersey ore body shown in A. (Modified after Briskey, 1981).     29   2.8.3. Phyllic alteration Phyllic alteration is moderately to well developed in the Highland Valley District, and is closely associated with mineralization. Phyllic alteration is fracture-controlled. At the Valley pit, vein “sericitic” alteration of Osatenko and Jones (1976) forms envelopes on quartz veinlets that are 0.5-25 mm in width. Sericite also forms replacement in fractured-controlled zones that range from 0.5 to 30 mm in width. There zones according to Osatenko and Jones (1976) are composed of fine-grained quartz, medium-grained sericite (2M1 type), minor calcite, brick-red hematite, kaolinitized and sericitized feldspar, sericitized biotite, bornite, chalcopyrite, pyrite (trace) and molybdenite. Areas with higher concentrations of vein sericitic alteration coincide with zones greater than 0.50% Cu. At Lornex, phyllic alteration is less developed but an important copper host (Casselman et al., 1995). The quartz-sulphide veinlets with sericite envelopes are typical for the phyllic alteration at Lornex and Highmont, but narrower sericite selvages are developed at Highmont than at Lornex (Reed and Jambor, 1976). At JA, phyllic alteration is also weakly developed (Figure 2.6). At Bethlehem, white mica described by Briskey (1981) and Briskey and Bellamy (1976) is widespread but fine-grained, being only been identified by XRD analysis. White mica is present in all but the most unaltered rocks of the Jersey and Huestis orebodies, whereas at the Iona pit, white mica is commonly correlated with the breccias. Briskey (1981) suggests that white mica abundance in the Bethlehem phase seems slightly higher than in the Guichon Variety. Higher concentrations of white mica are also roughly correlated with areas of higher than 0.1 wt % of copper. At Bethlehem, white mica mostly replaces orthoclase, and is commonly associated with calcite and epidote (Briskey and Bellamy, 1976).     30   Figure 2.6: Map distribution for green “sericite” (A) and chlorite (B) veins around the Valley deposit and the principal deposits at the center of the Guichon Creek batholith, also in the map the projection of batholith root zone to surface of Highland Valley. (Modified after Casselman et al., 1995).  2.8.4. Propylitic alteration: In the Valley deposit and peripheral zones as well as at Lornex, JA and Highmont, propylitic alteration is weakly to moderately developed. It is characterized by the alteration of plagioclase to less intense sericite, epidote, clinozoisite and calcite and the alteration of biotite to chlorite (Osatenko and Jones, 1976; Casselman et al., 1995). At Bethlehem, propylitic alteration is more visually prominent than in the other deposits. There, epidote dominates especially at the outer southern margin of Jersey and    31   Huestis (Briskey, 1981). Epidote is more abundant in the peripheral zones, around the hydrothermal biotite-dominated core (Figure 2.6; Briskey, 1981). Epidote occurs in veins, veinlets, filling fractures and disseminated replacing calcic plagioclase and primary mafic minerals (Briskey and Bellamy, 1976). At Bethlehem, epidote is associated with chlorite, white mica, calcite, quartz, specularite, chalcopyrite and pyrite (Briskey and Bellami, 1976). The association of actinolite with epidote and chlorite described by Briskey (1981) may indicate a sodic-calcic alteration assemblage. This will be explained in detail in Chapter 3.  2.8.5. Pervasive sericite and kaolinite This type of alteration has only been recognized at the Valley pit (Osatenko and Jones, 1976). It is interpreted to be “gradational from the propylitic alteration”. The defining characteristic of this type of alteration is the alteration of plagioclase by white/green finegrained sericite and kaolinite. This classification will not be used herein as muscovite and kaolinite are not in equilibrium (Seedorff et al., 2005). This alteration is considered intermediate argillic, and described below.  2.8.6. Intermediate argillic alteration Intermediate argillic alteration at Highland Valley is defined by the alteration of feldspars by kaolinite and sericite with or without montmorillonite (McMillan, 1985; Casselman et al., 1995). Intermediate argillic alteration is present in all the deposits in variable intensity. At the Valley deposit, kaolinite is the dominant clay-mineral in the deposit with lesser montmorillonite on the west side of the deposit (Jones, 1975). At Valley, argillic alteration is moderately to strongly developed in which the alteration intensity is related to fracture intensity. This alteration overprints propylitic and pervasive phyllic alteration (Casselman et al., 1995).     32   At the Bethlehem deposits, X-ray diffraction analyses by Briskey (1981) show that kaolinite and montmorillonite minerals compose only approximately 10% of the average modal composition in the propylitic, phyllic and potassic alteration. Mosaics of kaolinite normally replace plagioclase and hornblende and are associated with “white mica”, montmorillonite,  chlorite,  carbonates,  epidote,  quartz  and  secondary  plagioclase.  Montmorillonite is more intense in the phyllic zone of the Jersey pit where it replaces plagioclase and less commonly ferromagnesian minerals (Briskey, 1981).  2.9. Other nonmetallic minerals in Highland Valley district Black schorlitic tourmaline is present erratically across the Bethlhem deposits but is not common at the Valley and Lornex deposits (Briskey, 1981; McMillan, 1985). Tourmaline is abundant in breccias that have a quartz-rich matrix from the Iona zone and it is widespread marginally and into the ore zones (Briskey, 1981). Tourmaline is also present in the vicinity of and probably related to breccia bodies at JA, Highmont and South Seas near (McMillan, 1985). Actinolite is distributed throughout the Bethlehem deposits. According to Briskey (1981), smaller amounts of actinolite occurs mainly in veins and veinlets, as a product of alteration of hornblende, minor biotite and locally plagioclase. Briskey (1981) demonstrated that actinolite abundance decreases from the propylitic, potassic to phyllic alteration. Actinolite is also recognized at Highmont and JA. At Highmont, actinolite locally occurs in veinlets and patches (Reed and Jambor, 1976). Carbonates (mainly calcite), gypsum and zeolites are common through at Highland Valley as late-stage veins in-fill and alteration. Late calcite in veins (post-ore) is very common in all the deposits. Calcite replaces feldspars and coats fractures (McMillan, 1985). Gypsum is abundant as veins and filling fractures and post dates zeolites at Valley and JA (Casselman et al., 1995). At Bethlehem, calcite is common in the peripheral vein assemblage, abundant in breccia contents and widespread in veinlets throught the Bethlehem deposits (Briskey, 1981). Zeolite (laumontite) occurs in veins and as fracture coatings and as alteration halos around fractures, typically intergrown with gypsum. Zeolites are mostly    33   present in Bethlehem, Highmont and JA (Briskey and Bellamy, 1976; Red and Jambor, 1976).  2.10. Metallic minerals and zoning at Highland Valley: Valley deposit, Bethsaida Zone and Bethlehem deposits Metal-bearing sulfide minerals in the Highland Valley deposits are chalcopyrite, bornite, pyrite and molybdenite, with minor sphalerite, galena, pyrrhotite, tetrahedrite, enargite and covellite (Casselman et al., 1995). The typical pattern from centre to margin of the deposits is from bornite through chalcopyrite to a pyrite-dominant zone (Casselman et al., 1995; McMillan, 1985). Examples of the mode of occurrence of the metals in Highland Valley are shown in Figure 2.7. At the Valley deposit, the bulk of the chalcopyrite and bornite is correlated with areas of abundant vein sericitic alteration and quartz veinlets (Osatenko and Jones, 1976; Casselman et al., 1995). Scarce covellite, pyrrhotite, sphalerite and galena are also recognized. Molybdenite occurs with chalcopyrite with or without pyrite, usually in quartz veinlets in zones of vein sericitic alteration (Osatenko and Jones 1976). The Bethsaida Zone (Casselman et al., 1995) is located 1 km southwest of the Valley deposit. The area was defined by a chargeability anomaly and consists of weakly mineralized Bethsaida phase rocks. Minerals are similar to that in the Valley deposit (R.M. Tosdal and J.H. Dilles, 2009, written comm.). In the Bethlehem deposits, mineralization occurs within the dike swarm, in breccias or densely fractured zones along and/or adjacent to the Guichon quartz diorite-granodiorite and Bethlehem granodiorite contact (McMillan, 1976). Common metals are chalcopyrite, bornite, pyrite, specularite and molybdenite, with lesser magnetite and chalcocite and traces of tetrahedrite and galena (Briskey and Bellamy, 1976). Metal distribution at the Jersey orebody is concentric (Figure 2.8) with high-grade Cu largely contained in the bornite-rich central zone (inner halo). Chalcopyrite predominates outside of the inner halo, and Cu grades can exceed 0.5%. Low–grade Cu coincides with the pyrite halo (outer halo) (Briskey, 1981).     34   Specularite is vein-controlled and peripheral to the pyrite halo in the Jersey orebody. Specularite is associated with green sericite, epidote, quartz, carbonates, chalcopyrite, bornite and rarely tourmaline (Briskey, 1981). Briskey (1981) suggests a probable “zonal pattern” occuring in the Huestis orebody (Figure 2.8). Copper in the Iona zone is related to the breccia where it is erratically distributed (Briskey, 1981). Molybdenite is not abundant and is erratically distributed, commonly in the chalcopyrite outer zones of the deposit (Casselman et al., 1995).     35   Figure 2.7: Mineralization style in the Highland Valley district A. Quartz-muscovite-chalcopyrite±bornite vein of the Bethsaida Zone. B. Quartz-bornite-chalcopyrite-K-feldspar-biotite, and muscovite occurring in a vein of the Valley deposit. C. Chalcopyrite and quartz vein with oxide filled with crystals of calcite (Iona pitBethlehem). D. Hairline sulfide vein with no selvages cut the quartz monzonite host rock of Bethsaida. E. Photograph shows previous cut parallel to the vein, showing chalcopyrite and bornite (Bethsaida). F. Disseminated chalcopyrite of the D-vein selvage together with pervasive-coarse muscovite and quartz (Alwin mine). G. Plane polarized light photomicrograph shows pinkish bornite overgrown by yellowish chalcopyrite (Bethsaida Zone). H. Vein-controlled mineralization in phyllic alteration (Alwin Mine).     36   Figure 2.8: A. Metallic mineral distribution in the Jersey pit-Bethlehem deposits (specularite, pyrite, chalcopyrite and bornite). B.Vertical view of A (modified after Briskey 1981).     37   CHAPTER 3 Alteration assemblages at Highland Valley as a framework for hydrothermal muscovite and chlorite chemistry  3.1.Introduction The objective of this chapter is to establish the alteration types and cross-cutting relationships as well as to describe textural types of muscovite and chlorite within the context of the mapped alteration assemblages described in Chapter 2. In addition, one alteration assemblage not distinguished in previous studies is also described below. Rocks from three different intrusive phases within the Guichon Creek batholith are present in the Alwin-Valley-Bethlehem transect. They are of importance for the interpretation of the data since they can influence alteration minerals, physical-chemical properties and trace elements (for Chapter 4). These are: 1) the quartz-monzonite to granodiorite of the Bethsaida phase, which hosts the Alwin Mine, the Bethsaida Zone and the Valley deposit; 2) the more mafic quartz-diorite to granodiorite corresponding to the Guichon Variety of the Highland Valley phase (hornblende-rich granodiorite); and 3) the granodiorite of the Bethlehem phase (biotite-rich granodiorite), which together with the hornblende granodiorite hosts the Bethlehem deposits (detailed description in Chapter 2).  3.2. Samples Sampling was carried out in two campaigns. The first sampling campaign carried out in 2008 included 60 samples from outcrops and exposures hosted by the Bethsaida phase in a transect from the Alwin mine, Bethsaida Zone and the Valley deposit (samples collected by Richard Tosdal and John Dilles). The second sampling campaign was completed in 2009 across the three open pits of the Bethlehem mine, Huestis, Jersey and Iona; a total of 46 samples were collected. From the large suite of rocks collected, a group of samples were     38   selected for detailed study that best represent the range of muscovite and chlorite in rocks and in association with alteration assemblage. These samples include nine from the Bethsaida phase (transect from the margin of the Valley deposit, through the Bethsaida, ending at the Alwin mine, Figure 3.1) and sixteen samples from the Bethlehem phase and Guichon Variety collected around the pits forming the Bethlehem deposits (Figure 3.1). All samples selected for detailed petrographic study focused on the identification of the alteration halo of minerals and their compositions in the Alwin-Valley-Bethlehem areas. The following instruments were utilized to establish the paragenesis and alteration assemblages. These are: 1) A Nikon Polarizing Eclipse E600 POL microscope; 2) Scanning electron microscope (SEM) by energy dispersive spectroscopy (EDS) and backscattered electron imaging (BSE) with an accelerating voltage beam 15 kV. The SEM is a Phillips XL30 with Bruker Quantax 200 and microanalysis system and light element XFLASH 4010 silicon drift detector. Photomicrographs tracked the analyzed point and were compared with the SEM images to ensure analysis of the proper location to minimize ambiguity of results. 3.3. Local setting: Highland Valley host rock Host rock compositions in the samples from the Bethsaida phase transect (Valley deposit-Valley margin -Bethsaida Zone –Bethsaida margin- Alwin mine) (Figure 3,1) indicate slight textural and composition variations from a phenocryst-crowded granodiorite at Alwin mine and Valley deposits to mainly equigranular granodiorite in the Bethsaida Zone. Despite the slight variation in phenocryt content, the Bethsaida rocks are relatively homogeneous and are hereafter referred to simply as granodiorite (Figure 3.2). Field observations of the Guichon Variety and Bethlehem phase demonstrate that the Guichon rocks are mainly granodiorite, rich in hornblende and lesser biotite, whereas the Bethlehem phase consists of granodiorite rich in biotite and lesser hornblende. Thus, the Guichon Variety is referred to as hornblende granodiorite and the Bethlehem phase as biotite granodiorite (Figure 3.1, Figure 3.2).     39   Figure 3.1: A. Sample location map transparent-colored according to the intrusive phase rock of the Guichon Creek batholith map (Figure 2.2, chapter 2). B. Schematic cross-section as indicated in A.     40   Figure 3.2. Photographies having the dominant host rock types from the studied transect across Highland Valley district (Alwin-Valley-Bethlehem). A. Quartz monzonite sample from the Bethsaida phase. B. Granodiorite sample from the margins of the Bethsaida phase. C. Mafic enclave in granodiorite south of Jersey Pit - Bethlehem phase. D. Sample corresponding to the least altered rock of the Guichon Variety.  3.4. Muscovite and chlorite textural classification 3.4.1.Textural classification of muscovite Six textural type of white mica were identified in Alwin mine, the Bethsaida Zone, Valley deposit and across the Bethlehem deposits (Table 3.1). The white mica selected for this study is muscovitic based on electron microprobe analysis (see chapter 4). The textural classification is based on grain size and mode of occurrence. All muscovite described herein is a product of alteration. Brief sample descriptions follow, with reference to hand samples, petrography and SEM.    41   Table 3.1: Textural muscovite definition based on grain size and place of occurrence  Medium to coarse-grained pervasive muscovite (Mc) and muscovite in vein (Mv) Medium to coarse-grained crystals ranging from 0.4 mm to 1 mm define the muscovite textural type Mc (Table 3.1). Where present, muscovite Mc is commonly pervasive through at the rock and lacks a preferred orientation (Figure 3.3C). It is best developed in the rocks of the Bethsaida phase specialy in samples from the Alwin Mine, and the Valley deposit and is less common in the Bethsaida Zone. Textural type Mc has not been observed around the Bethlehem deposits. In hand sample, Mc is pearl-silver color and intergrown with coarse quartz. Muscovite textural type Mc alters mainly to plagioclase and K-feldspar. Muscovite in veins (Mv) forms a subset of Mc, as these samples appear transitional to muscovite Mc. Textural type muscovite Mv is medium to coarse grained, oriented parallel to the vein margins (Figure 3.3A). Muscovite Mv is recognized in samples from the Valley pit (Bethsaida phase) only.    42   Medium to fine-grained pervasive muscovite (Mp and Mfp) Medium-grained muscovite with crystals from 0.1 mm-0.4 mm forms the textural type Mp (Table 3.1). Plagioclase and K-feldspar are moderately to pervasively replaced by Mp muscovite. Individual crystals have no preferred orientation and locally fill fractures in cores of plagioclase. Muscovite Mp is intergrown with quartz, apatite, zircon and rutile. Some samples show remnants of igneous textures whereas in others igneous texture is obliterated by alteration. In the latter case, muscovite Mp is accompanied by abundant medium grained quartz and copper sulfides. Examples are samples HVD032, HVD020, HVD036 from the Bethsaida Zone (Figure 3.1, 3.3B and D). Muscovite Mp is best developed in rocks from the Alwin mine, Bethsaida Zone, and less around the Valley deposit and the Bethlehem deposits. In the Bethlehem deposits, samples that present this type of mica texture are BTA26 (with a grain size around 0.3mm) and BTA28, BTA18 and G178 (grain sizes 0.10.3mm). In contrast to muscovite Mp from the Bethsaida intrusive phase, muscovites Mp around Bethlehem deposits are associated with quartz, calcite, chlorite, epidote and specular hematite. Fine-grained muscovite (Mfp) forms a subset in the Mp textural type. It is characterized by grain size around 0.1mm. This textural type is observed for example in samples BTA16 and BTA14 from south Jersey and north of Iona pit, respectively (Figure 3.3D). Medium-grained muscovite replacing biotite (Mb) Medium to coarse-grained muscovite with a defined orientation of cleavage parallel to biotite orientation defines textural type Mb. This mica replaced biotite or chlorite that had previously replaced biotite. Although there is no relict of biotite in most of the samples, the original mineral can be inferred from the textural characteristics and other associated secondary mineral inclusions of rutile and titanite. This textural type is mainly present in the Bethsaida phase, but it is locally present in the Bethlehem phase (sample BTA16). This textural type is largely absent in samples from Bethlehem phase and Guichon Variety. In samples from the Valley deposit, relicts of biotite are partly replaced by textural type Mb and chlorite (Figure. 3.3B). In the Bethlehem phase, Mb textural type is commonly associated    43   with more pervasive mica type (Mp). This Mb textural type replaces biotite directly without evidence for an intermediary chlorite replacement. Very fine-grained muscovite dusting in plagioclase (Md) Muscovite textural type Md consists of individual crystals of around 0.02 mm in diameter concentrated in igneous plagioclase cores (Figure 3.3F) and locally in igneous Kfeldspar. The original rock texture is well preserved. The textural type Md is common at Bethlehem deposits where it is associated with rocks altered to a sodic-calcic assemblage, which is later overprinted by illite (see detailed description in the alteration section below). 3.4.2. Textural classification of chlorite Chlorite classification is based on mode of occurrence and birefringence color. Chlorite has not been observed in the muscovite selvages of quartz-sulfide veins from Bethsaida phase except in the Valley deposit, but it is abundant across the Bethlehem deposits where it is intimately associated with epidote (sodic-calcic assemblage) and muscovite (phyllic assemblage). At the Valley deposit, chlorite together with muscovite replaces biotite. In the Bethlehem phase and Guichon Variety rocks, chlorite replaces biotite and amphibole (samples BTA20, G175 and G184). In the sodic calcic altered areas (see below), titanite is the dominant inclusion mineral with lesser rutile and apatite. Chlorite birefringence color varies in the Valley deposit and the Bethlehem deposits (Table 3.2). In the Valley deposit, the chlorite birefringence is brown, whereas at Bethlehem phase and Guichon Variety rocks it varies from greenish-brown to brownish and blue-purple. In the sodic calcic altered areas of Bethlehem phase, epidote is associated mostly with blue chlorite whereas brown-green chlorite is mostly associated with muscovite.     44   Table 3.2: Chlorite birefringence colors and mineral replacement. Chlorite occurrences from the Bethlehem phase, Guichon Variety and the Valley deposit     45   Figure 3.3: Photomicrographs of the principal muscovite and chlorite textural types taken in cross-polarized light. A. Muscovite in vein (Mv) and quartz intergrown with K-feldspar alteration (HVD044, 770 level-Valley deposit). B. Muscovite replacing biotite (Mb), orientation reflects former biotite grain and encloses rutile and titanite; Mb is also surrounded by pervasive muscovite (Mp) (HVD039, Alwin Mine). C. Coarse muscovite Mc intergrown with quartz (HVD049, 1000 level-Valley deposit). D. Fine pervasive muscovite (Mfp) with Mb overprinted by calcite (BTA16-Bethlehem). E. Blue chlorite surrounded by pervasive muscovite (G178Bethlehem). F. Dusty muscovite (Md) alters plagioclase, green chlorite with inclusions of epidote (BTA04Bethlehem). Quartz (Qtz), K-feldspar (K-spar), rutile (Rut), apatite (Ap), calcite (Calc), magnetite (Mg), epidote (Epi), chlorite (Chl), illite (Illi).     46   3.5. Alteration assemblages The alteration assemblages and distribution described below is based on petrographic observations from the samples taken along the transect Alwin-Valley-Bethlehem. Table 3.3 summarizes the alteration phases. A schematic mineral assemblages and alteration sequence is outline in Figure 3.4 and summarizes the mineral assemblages and their compatible alteration types in the transect Alwin-Valley-Bethlehem study herein. Figure 3.5 illustrates schematically the spatial distribution of the alteration emplaced in their respectively phases. The alteration identified in this study is placed in context of previous work summarized in Chapter 2 (McMillan, 1976; Osatenko and Jones,, 1976; Briskey and Bellamy,, 1976; Briskey 1981; Casselman et al., 1985).  3.5.1. Sodic calcic alteration Sodic-calcic alteration, in contrast to the other types of alteration, has not been previously recognized as a distinct alteration assemblage in Highland Valley district. Instead, it has been included within the propylitic alteration (see chapter 2; Briskey, 1981). It is pervasive in outcrops in the Bethlehem area whereas around Valley it forms discrete fracture controlled zones. The Mineral association is albite, titanite, chlorite, magnetite, epidote and actinolite. The samples are sulfide poor. Alteration, where intense, destroys the original rock texture resulting in a characteristic cream-pinkish color, where the pink-stained color can be attributed to the hematization of the intrusive host rock (Briskey, 1981). At the Bethlehem deposits, sodic-calcic alteration is strongest in the southern area of the Huestis pit where Bethlehem biotite granodiorite is the dominant host rock. Albite and epidote are overprinted by dusty muscovite, brown to blue chlorite and illite (Table 3.3; Figure 3.6 A, B and C; Figure 3.4). Two generation of epidote veins are present: early epidote+quartz veins have selvages of albite that are characteristic of the sodic-calcic. Other epidote+quartz and epidote veins are present but as a late stage and lack albite. These are locally overprinted by calcite veins (Figure 3.6 D; Figure 3.4). Dusty muscovite is common in minor quantity in this alteration type, with crystals sizes ~0.02 mm altering primarily     47   plagioclase. Titanite is present as inclusions in chlorite. Weak to moderate sodic-calcic alteration is present in the Jersey pit, where it is probably transitional between propylitic alteration and more intense sodic-calcic alteration, as has been described elsewhere (Dilles and Einaudi, 1992).     48   Table 3.3: Detailed classification of assemblages based on samples of the studied transect Alwin-ValleyBethlehem. Mc: coarse muscovite, Mp: pervasive muscovite, Mfp: fine pervasive muscovite, Md: dusty muscovite (see texture classification table 3.1), Chl:chlorite, Epi: epidote, Calc:calcite, Illi:illite, Kao: kaolinite, Smec:smectite, Alb:albite, Qtz:quartz, SpHm: specular hematite, Mg: magnetite, Cp: chalcopyrite, Hm: hematite, Bn: bornite, Rut:rutile, Bar:barite, Fluo:fluorite, Bio: biotite, Ksp: K-feldspar, brw:brown, blu: blue the latest correspond to the chlorite birefringence color.     49   Figure 3.4: A. Mineral assemblages and alteration phases from Alwin mine through the Valley deposit based on crosscutting and minerals associations done in this study. B. Schematic mineral assemblage and alteration phases of the Bethlehem deposits base on this study and previous studies from Osatenko and Jones (1976), and Briskey (1981). Thick solid lines represent abundance of the mineral present everywhere in the assemblage, thin solid lines represent less abundance of the mineral present everywhere in the assemblage, dash lines represent sporadic mineral in the assemblage.     50   Figure 3.5: A. Map showing alteration outline according to the samples considered for this study (see Table 3.1). The total length of the Alwin-Valley- Bethlehem transect is about 10 km. B. Schematic cross-section as indicated in A.     51      52   Figure 3.6: Sodic–calcic alteration type assemblages from Bethlehem phase. A. Hand sample shows early epidote-quartz vein with selvages of albite overprinted by illite and calcite (BTA04 sample). B. Cross-polarized light photomicrograph of the sample in picture A. C. Hand sample shows typical early epidote veins with selvages of albite (Bethlehem phase). D. Cross-polarized light photomicrograph shows late epidote vein cutting fine grained albite in rock, and relicts of feldspar alters to illite (G107 sample). E. Cross-polarized light photomicrograph shows blue chlorite with inclusion of magnetite, epidote and dusty muscovite (BTA02 sample). F. Cross-polarized light photomicrograph shows late calcite vein cutting feldspar altered to illite (BTA04 sample). G. Backscattered electron image (SEM) of chlorite (enlargement of F photomicrograph) with inclusions of titanite, magnetie and apatite. Quartz (Qtz), albite (Alb), chlorite (Chl), illite (Illi), epidote (Epi), calcite (Calc), plagioclase (Plag), apatite (Ap), magnetite (Mg), titanite (Tit). Figure caption on page 52.     53   3.5.2. K-feldspar and biotite alteration The assemblage K-feldspar and biotite defines the principal minerals of potassic alteration (see chapter 2). Representative samples in the transect Alwin-Valley-Bethlehem deposits are principally from by the Valley deposit samples that correspond to the deeper levels of the pit. In the Valley deposit, samples from the 770 and 1000 levels are characterized by hydrothermal K-feldspar, quartz and biotite, where K-feldspar forms as selvages to the quartz veins (Table 3.3). Coarse muscovite (Mc) is intergrown with Kfeldspar that forms selvages to the quartz veins or fills fractures. Biotite is overgrown by brown chlorite and coarse muscovite (Figure 3.4). Rutile and barite are associated with chlorite in the deepest sample (HVD044). Fluorite is associated with barite in the chlorite from the upper part of the Valley deposit sample (Figure 3.7).     54   Figure 3.7: K-feldspar and biotite alteration (potassic alteration). A. Hand sample photograph from Valley deposit (770 level). Blue square represents the thin section area with spots selected for microprobe analysis (reference to chapter 5), red dashed line represent quartz vein with K-feldspar overprinted by coarse muscovite, black circles represent areas for SWIR measurement (reference to appendix). B. Hand sample photograph from Valley deposit (1000 level), similar description than A. C. Backscattered electron image (SEM) showing remnant of K-feldspar overgrown by muscovite in vein D. Cross-polarized light photomicrograph shows muscovite Mb intergrown with chlorite, also dusty illite. E. Cross polarized light photomicrograph from the Valley deposit (1000 level) shows coarse muscovite and chlorite overprinting K-feldspar, orange dashed line represent the area of enlarged in F. F. chlorite and muscovite overgrown biotite, also dusty kaolinite alters feldspars. G. SEM photomicrograph shows fluorite and barite intergrowth in the chlorite-muscovite border (1000 level sample from Valley Pit). Quartz (Qtz), K-feldspar (K-spar), albite (Alb), chlorite (Chl), illite (Illi), kaolinite (Kao), biotite (Bio). Fluorite (Flu), barite (Bar).     55   3.5.3. Phyllic alteration (muscovite – chlorite paragenesis) Muscovite and chlorite form part of the phyllic alteration. Phyllic alteration is moderately to well developed across the deposit. In the Bethsaida phase, phyllic alteration is closely linked to the quartz-sulfide veins with muscovite selvages that can be mapped from the Valley deposit to the Alwin Mine over than 4 km. Along the transect, alteration selvages in the vein vary with the host rock type. In the Bethsaida granodiorite, chlorite is completely replaced by muscovite, whereas in the more mafic Bethlehem phase and Guichon Variety, coarse chlorite is intergrown with muscovite in the selvages. At Bethlehem, quartz-sulfide veins with muscovite-chlorite selvages are locally observed in areas of intense phyllic alteration. The quartz-sulfide veins with muscovite selvages from the Bethsaida phase and the quartz-sulfide veins with muscovite-chlorite selvages from the Bethlehem phase and Guichon Variety are composed of chalcopyrite-bornite with quartz and muscovite that vary in texture and size (Figure 3.8; Figure 3.4). Muscovite and chlorite partially to completely replace feldspars and mafic minerals. Table 3.3 shows the mineral association for the phyllic alteration subdivided into chlorite-muscovite and muscovite assemblages. The width of these veins varies laterally from pervasive flooding (centimeter scales) of the wallrock with massive pale green phengitic-muscovite (typical in the Alwin Mine) to hairline millimetric, fine-to medium-grained muscovite that is found throughout the Bethsaida phase (Figure 3.8D). Replacement of feldspar by muscovite is intense close to the vein where it destroys the original texture of the rock (Figure 3.9 C and D). Muscovite textural types are also indicative of the intensity and potentially depth of the system. Coarse muscovite is commonly observed in the relatively deep potassic zone in the Valley Pit, but also forms at the Alwin Mine. Medium-grained pervasive muscovite destroys plagioclase and K-feldspars completely in the Bethsaida Zone. Fine-grained to medium-grained pervasive muscovite in plagioclase is more common in a relatively shallower Bethlehem deposits (Figure 2.3A). Rutile is common with the muscovite+chlorite+quartz+sulphides assemblages. In the Bethsaida phase where muscovite is more pervasive, and the muscovite textural type Mb (muscovite after biotite) occurs, rutile replaces titanite. This is not as common in the phyllic areas of Bethlehem phase and Guichon Variety as in Bethsaida. Rutile in porphyry deposits is     56   closely related to the hydrothermal alteration of titanium-rich phases such as titanite, biotite, Ti-magnetite and ilmenite at temperatures between 400°C and 700°C (Rabbia et al., 2009). At Highland Valley, rutile results from the biotite breakdown. Two probable events of phyllic alteration are present in the breccia at Iona: clasts have been affected by pervasive muscovite (Mp) with brown chlorite and quartz, whereas the clastic matrix is altered by brown to blue chlorite and pervasive muscovite with quartz overprinted by late epidote (Figure 3.10). Chorite occurs as breccia cement. Specular hematite forms part of the phyllic assemblage at the Bethlehem deposits. Specular hematite locally replaces chlorite.     57   Figure 3.8. Distal veins from Highland Valley cross section Alwin-Bethsaida Zone-Valley deposit. A. Pervasive muscovite flooding at Alwin mine with chalcopyrite and bornite. B. Hairline quartz-sulfide vein with selvages of green sericite in a relatively fresh rock from Bethsaida Zone. C. Muscovite flooded chalcopyritequartz vein (Alwin mine). D. Quartz-sulfide with selvages of dark muscovite (margin Bethsaida). E. Quartzsulfide (chalcopyrite+bornite) vein with muscovite selvages from the Valley deposit margin, cream colored part correspond to kaolinite with minor illite and albite. Chalcopyrite (Cp), quartz (Qtz), bornite (Bn).     58   Figure 3.9: Representative samples of phyllic alteration. A. Hand sample shows pervasive muscovite with quartz and chalcopyrite (Bethsaida Zone) B. Cross-polarized light photomicrograph of the same sample described in A, shows coarse muscovite (Mc) with inclusions of chalcopyrite surrounded by pervasive muscovite (Mp). C. Hand sample shows quartz-sulfide vein with muscovite selvage (Bethsaida margin) D. Photomicrograph of the same sample described in C, under cross-polarized light, represents the area marked as circle in C and shows pervasive muscovite alteration in the selvages, texture is preserved on the border of the selvage. E. Hand sample shows specular hematite (SpHm) vein cemented with calcite+epidote cutting pervasive muscovite and minor chlorite (Iona pit-Bethlehem phase). F. Cross-polarized light photomicrograph of sample described in E, specular hematite surround chlorite, calcite and epidote filling spaces in a pervasive muscovitic altered rock. Quartz (Qtz), chalcopyrite (Cp), chlorite (Chl), kaolinite (Kao), epidote (Epi), calcite (Calc), specular hematite (SpHm).     59   Figure 3.10: Breccia sample (G192) from the Iona pit-Guichon Variety. A. Plane-polarized light photomicrograph shows brown chlorite cement in the breccia. B. Cross-polarized light photomicrograph of the same sample shows clast of the breccia altered to muscovite, quartz and brown chlorite and matrix with quartz, muscovite, blue chlorite and epidote. Chlorite (Chl), quartz (Qtz), epidote (Epi).     60   3.5.4. Distal phyllic alteration Distal phyllic alteration shows different characteristics across the district compared with samples from the more proximal intense phyllic alteration zone (Figure 3.11). It is defined by chlorite, illite, scarce muscovite and lesser epidote (Table 3.3). Chlorite and epidote partly replace amphibole and biotite (Figure 3.4). Hydrothermal magnetite is associated with chlorite. Albite is present in minor amounts. Veins of epidote and calcite are absent, which distinguishs the assemblage from the sodic-calcic alteration zone. This alteration is more veinlet-controlled than pervasive. Distal phyllic alteration is herein defined as an alteration zone separate from phyllic alteration, the latter representing a more proximal setting.     61   Figure 3.11: Distal phyllic alteration around the Bethlehem deposits A. Hand sample (G134) located north of the Jersey pit, Guichon Variety. B. Cross-polarized light photomicrograph described in A, shows hornblende partially altered to chlorite, inclusions of magnetite and feldspar slightly altered to illite. C. Hand sample shows albite replacing K-feldspar (sample G184, marginal zone of the Jersey pit, Guichon Variety) D. Cross-polarized light photomicrograph of sample described in C, shows chlorite replaces biotite and hornblende. E. Hand sample show most altered rock with albite replacing K-feldspar, with epidote and chlorite (sample G175 south of the Iona pit, Bethlehem phase) F. Cross-polarized light photomicrograph shows chlorite and epidote replace hornblende. Epidote (Epi), magnetite (Mg), illite (Illi), hornblende (Hn), chlorite (Chl), albite (Alb), biotite (Bio), plagioclase (Plag).     62   3.5.5. Late clay alteration Kaolinite, illite and/or smectite form a common late stage of alteration (Figure 3.4). These clay minerals are present in the deepest part of the Valley deposit and across the Bethlehem deposits and give the rock a dusty brownish appearance in transmitted light. Clays are not present where muscovite alteration is very intense. Kaolinite was detected by XRD in samples from the Alwin Mine, the Valley deposit and margin of the Valley deposit. At the Alwin mine, kaolinite completely altered phenocrysts of feldspar and is overgrown by calcite (Figure 3.12 A and B). At the margin of the Valley deposit, kaolinite with ankerite replaced K-feldspar (Figure 3.12 C and D). Kaolinite is usually evident as an outer selvage to muscovite-quartz-chalcopyrite-bornite veins (Figure 3.8E and 3.9C; Table 3.3). Illite and illite+smectite, detected by XRD, are present mainly in samples from Bethlehem phase and Guichon Variety and the Valley deposit rocks. Illite and smectite occur with kaolinite and are only overprinted by late epidote and calcite veins. Montmorillonite was not identified in any of the samples.     63   Figure 3.12: Clay minerals. A. Cross-polarized light photomicrograph of Alwin mine shows coarse muscovite (Mc) with quartz, chalcopyrite and rutile. The green arrow shows the area of enlargement in the next picture. B. Backscattered electron image (SEM) enlargement of area marked with an arrow in A, shows kaolinite replacing feldspar and later overgrown by calcite. C. Hand sample photo shows quartz-sulfide with muscovite selvage vein and kaolinite in the wallrock (HVA01 -Valley margin). D. Cross-polarized light photomicrograph of sample described in C, shows kaolinite replacing feldspar in less physically altered rock outside of the quartzsulfide vein with muscovite selvage. Kaolinite is overgrown by ankerite. Quartz (Qtz), chalcopyrite (Cp), rutile (Rut), kaolinite (Kao), calcite (Calc), apatite (Ap), k-feldspar (K-spar), ankerite (Ank).     64   3.6. Discussion Muscovite and chlorite in Highland Valley occur principally in the potassic and phyllic alteration zones. In the potassic alteration zones, coarse white muscovite and muscovite in veins are abundant and associated with secondary K-feldespar, quartz, chlorite and biotite. In the muscovite-chlorite paragenesis, representing phyllic alteration, green to white pervasive muscovite together with chlorite form part of the selvages of quartz-sulfide veins. From the Valley deposit to the Bethsaida Zone and Alwin mine, quartz-sulfide veins with muscovite selvages can be mapped over a 4 km horizontal distance. Thus, the phyllic alteration hosted in the Bethsaida phase is a laterally extensive alteration zone affecting a single rock type. In the more mafic host rocks of Bethlehem phase and Guichon Variety, the quartz-sulfide veins with muscovite-chlorite selvages are less widespread. Hence the alteration minerals at Highland Valley are host rock-controlled since in the more mafic rocks at Bethlehem, chlorite is more abundant. Muscovite and chlorite also vary texturally depending on the host rock. Thus, coarse muscovite and intense medium-grained pervasive muscovite are very common in the Bethsaida phase, whereas medium to fine-grained muscovite is common in the Bethlehem deposits (Table 3.4). This textural variety is also consistent with muscovite being finer-grained at shallower depths of emplacement than Valley, as inferred by Ager et al., (1973) and McMillan (1976) (see chapter 2, Figure 2.3B). The presence of dusty muscovite mostly occurring in the sodic-calcic alteration is probably the result of late overprint. XRD analyses of these samples show some of them are mainly illite and electron microprobe of the slightly coarser grains confirm existence of muscovite. Therefore these samples are probably a mixture of illite – muscovite (Table 3.4). Table 3.4: Muscovite textural types and corresponding alteration types in which it is mostly present.     65   CHAPTER 4 Variation of muscovite and chlorite composition in the Highland Valley district  4.1. Introduction The Highland Valley porphyry district represents an excellent opportunity to examine the lateral extent of large-scale hydrothermal circulation that constitutes the mineralizing porphyry environment. In porphyry systems, the evolution of these hydrothermal fluids and the interaction with the protolith at different pressure and temperature form halos of alteration in which minerals such as muscovite and chlorite are commonly present and occur over a wide range of temperature and fluid chemistry. Within this environment, the chemistry of chlorite and muscovite can be indicative of the degree of interaction between fluids and the host rock since these minerals may host variably mobile elements depending on the distance from the center of the system. This chapter presents analytical data from muscovite and chlorite in the Highland Valley porphyry district along the transect from Alwin to the Valley and the Bethlehem deposits. Quantitative major element compositions were analyzed using electron microprobe (EMPA). These results were later compared with short-wave infrared spectral data (SWIR). Laser ablation –inductively coupled plasma spectrometry (LA-ICP-MS) was applied to gain a better understanding of the trace element zonation along the same transect (Alwin-ValleyBethlehem). These data are then compared to whole rock geochemistry (WRG) data, which typically are more readily available in an exploration setting. Additional XRD analysis were important to establish correct mineral assemblages (see appendix).     66   4.2 Methodology and sample preparation. 4.2.1. Electron microprobe methodology Electron microprobe analyses of muscovite and chlorite were done on polished thin sections on a fully automated CAMECA SX-50 instrument, operating in the wavelengthdispersion mode with the following operating conditions: accelerating voltage, 15 kV; beam current, 10 nA; peak count time, 20 s (40 s for F, Cl); background count-time, 10 s (20 s for F, Cl); spot diameter, 10 µm. Data reduction was done using the 'PAP' φ(ρZ) method (Pouchou and Pichoir 1985). For the elements considered, the following standards, X-ray lines and crystals were used: synthetic phlogopite, FKα, TAP; Sodium albite, NaKα, TAP; Aluminum kyanite, AlKα, TAP; synthetic phlogopite Flourine, MgKα, TAP; synthetic phlogopite, SiKα, TAP; scapolite, ClKα, PET; synthetic phlogopite, KKα, PET; diopside, CaKα, PET; rutile, TiKα, PET; synthetic magnesiochromite, CrKα, LIF; manganese synthetic rhodonite, MnKα, LIF; Iron synthetic fayalite, FeKα, LIF; Barium barite, BaLα, PET. Muscovite and chlorite grains texturally defined in Chapter 3 were analyzed using the electron microprobe. Several measurements per grain were done to obtain better representation. Microprobe data was determined in wt% oxide. Contained Fe was reported as FeO. The detection limit that applies for analysis of muscovites and chlorites are given in Table 4.1. Oxide percent values less than the detection limit were considered as zero. Data were calculated in an excel spreadsheet in which formulas were normalized on the basis of 11 anhydrous oxygens for white mica, and 14 anhydrous oxygens for chlorite. The water content was not measured. Water is calculated based on mineral stoichioimetry, assuming full occupancy of the site by F, Cl and OH. Final chemical formula data were determined on the basis of the criteria outlined in Table 4.2. Graphical depiction of compositional data were prepared using IoGas software. Entire data set is in Appendix A3.     67   Table 4.1: Detection limits for electron microprobe analysis are 3-sigma peak counts above background counts adjusted for standard counts and ZAF corrections.  Table 4.2: Muscovite and chlorite parameters for formula standardization. Octahedral (Oct), cation (cat), tetrahedral (Tet), oxide (Ox), ions per formula unit (pfu).     68   4.2.2. Short wave infrared methodology (SWIR) Short wave infrared methodology was used with a ASD Terraspec® portable reflectance spectrometer. Analytical spectra interpretation utilized The Spectral Geologist software. Two scans were taken for each rough cut offcut from thin sections and the scan with the better analytical signal was chosen. Data was exported to Excel and each graphic is compared with standard muscovite and chlorite models from the library default file of the software. Total description of SWIR data in Table A6.1.  4.2.3. Laser ablation methodology Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was completed at the W.M. Keck Collaboratory for Plasma Spectrometry at Oregon State University USA. Muscovite and chlorite from selected samples were separated and polished grain mounts were prepared from these samples. In situ laser ablation was done on three thin section samples. The term “grain-mount” comes from encapsulating the hand picked mineral with epoxy-based resin in a plastic mold under relatively low temperatures. The detailed sample preparation procedure is summarized below. Grain-mounts maximize the amount of data obtained in a short amount of instrument time. They also are easier for running standards. In addition, the analytical precision is better and the detection limit is lower for grain-mounts because the analyzed grains are thicker than the 30 µm for polished sections. The disadvantage of this method is the time-consuming sample preparation and the loss of paragenetic context of the analyzed grains. Using thin section samples for LA-ICP-MS allows for better tracking of the grains with backscattered electron image (SEM) photos and is the best way to get information on the zonation of minerals composition. Laser ablation analysis on thin sections was the preferred method for the analysis of specific muscovite and chlorite where the textural context was important. Fifteen muscovite-rich samples from the Alwin mine, the Bethsaida Zone, the Valley Deposit and the Bethlehem pits and eight chlorite samples from the Valley Deposit and across the Bethlehem pits were selected for grain mount method, and three samples from the     69   Alwin Mine, Valley Deposit and east of Jersey pit-Bethlehem were selected for thin section method. Laser sample preparation for using grain-mount and thin section techniques Grain-mount sample preparation was made from coarse and pervasive muscovite and chlorites. Separation of muscovite was done by crushing the sample and hand-picking the muscovite and chlorite crystals. After separation, grain-mount preparation was carried out as follows: 1.- A glass petrographic slide was prepared using a double-sided tape by attaching a double sided tape to a glass slide commonly used for thin-section preparation. 2.- Under a binocular microscope, grains were selected and mounted in a row. A map of the grains with the respective sample number was prepared. Mica sheets were placed parallel to basal cleavage (001). As many grain samples as possible were placed on a slide, keeping the outer few mm free of mineral grains. 4.- A plexiglass ring (25mm plastic mould) was placed around the grains and pressed down firmly so it sealed around the base. 5.- The epoxy (epoxicure) was mixed: 5 parts resin and 1 part hardener, stirred for 2 minutes for thorough mixing, poured carefully into the ring until it gently covers the grains. 6.-Under a binocular microscope, a fine wire to tease out any air bubbles was used. 7.-The moulds were put in a 50°C oven for 4 hours. 8.-These were removed from the oven and left to cool for an hour before polishing. The final product was called a “plug”.  Plug Test: HVD049, BTA28, G131 (muscovites and chlorite) Plug 1: samples HVD049, HVD 20, G178 (all muscovites) Plug 2: samples HVD044, HVD050, BTA18, BTA26, BTA14 (all muscovites) Plug 3: samples HVD039, HVD032, HVD036, HVD06 (all muscovites) Plug 4: samples HVA01, BTA28, BTA16 (all muscovites)     70   Plug 5: samples HVD049, G178, BTA14, BTA16, BTA04 (all chlorites) Plug 6: samples HVD044, G131, BTA20 (all chlorites) Thin section 1: sample HVD039 (all muscovite) Thin section 2: sample HVD049 (muscovite), sample BTA20 (chlorite) The “plug Test” was made to test the quality of the analysis (the final data of this plug was not considered since the analysis were carried out with a smaller laser spot size). Major element compositions of the same samples have been previously analyzed in polished thin section on the electron microprobe. Due to the softness of the micas and chlorites, and the different sizes of these minerals, polishing them is the key part of the procedure. The polishing process was as follows: starting with 400 grit the samples were gently polished until the epoxy layer was exposed. Then a 600 grit polish was used followed by a 1200 grit polish, carefully checking the samples with a microscope until the micas were exposed. Care was taken to avoid loosing the small sheet grains. Finally, a 1.0-micron alumina powder mixed with water was used to gently polish the plugs for better visibility under the laser microscope. The thin section sample preparation for laser ablation is relatively simple. Commercial thin section preparation facilities (e.g., Vancouver Petrographics) readily prepare adequate polished sections. Polished sections were used for samples where different textural type of muscovite and chlorite were analyzed. Prior to the laser analysis, thin sections were analyzed using backscattered electron imaging to determine the exact muscovite and chlorite grains. LA-ICP-MS technique Trace element concentrations were obtained with a New Wave DUV 193 µm ArF Excimer laser and VG PQ ExCell Quadrupole ICP-MS. Ablation was done using He as the aerosol carrier gas flow (0.81/min), a nebulizer gas flow (0.95 l/min) (Ar) and a outer cool gas flow (13.00 l/min) (Ar) with a RF power of 1350 W, a vacuum pressure of 8.0 x 10-7 mbar (analyzer) and 1.6 mbar (expansion chamber) (Kent et al., 2004). Each individual    71   analysis represents 45 seconds of data acquisition during ablation with a wavelength of 193 nm, frequency of 4 Hz for the grain mounts samples and 3 Hz for the thin section samples. The spot diameter was 100 µm for grain mounts and thin sections. Pulse duration was 15 ns and the output energy was 200 mJ at 193 nm (~15 J/cm2). The calibration standard was GSE1G (see Appendix A4, Table A4.1) and the secondary standards BCR-2G and BHVO-2G. Ten standards were used for each run of approximately 45 sample measurements. SiO2 wt% measured by electron microprobe was used for the internal standard calculation. 7Li, 29  11  B,  Si, 31P, 45Sc, 47Ti, 51V, 52Cr, 55Mn, 59Co, 63Cu, 65Cu, 66Zn, 68Zn, 75As, 77Se, 85Rb, 86Sr, 95Mo,  118  Sn,  125  Te,  133  Cs,  137  Ba,  138  Ba,  182  W,  208  Pb,  209  Bi,  232  Th,  238  U,  205  Tl concentrations were  measured for each data point. Laser ablation measures two isotopes for Ba, Cu and Zn. For these elements, only the measured concentrations of the more abundant isotope (63Cu, 138Ba, 66  Zn) have been plotted in the diagrams. The analytical run takes 45 seconds for each point selected. Initial data was reduced  using LaserCalc 2.0 and Laser Tram 2.2, software designed by Adam Kent (Oregon State University). Final values after selection are presented in this chapter. The total result gave 406 analyses from which only 276 were selected on the basis of the analytical quality (error statistics with low errors and homogeneity of material analyzed).  4.2.4.Whole rock geochemistry methodology Aliquots of the same samples used for polished sections were sent for multi-element geochemical analyzis. Samples were analyzed at ALS-Chemex laboratories in North Vancouver, being analytical package ME-MS61. This Ultra-Trace Package in which the elements are analyzed by ICP-MS following HF-HNO3-HClO4 digestion, HCl leach, provides elemental concentration data for Ag, Al, As, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, Ge, Hf, In, K, La, Li, Mg, Mn, Mo, Na, Nb, Ni,P, Pb, Rb, Re, S, Sb, Sc, Se, Sn, Sr, Ta, Te, Th, Ti, Tl, U, V, W, Y, Zn, Zr and Cu. However, resistive minerals such as zircon may be incompletely dissolved during this procedure (ALS Laboratory group, 2011), thus limiting the reliability of some elements such as Zr, Hf and Nb. Comparing the analytical data produced during this study through the 4-acid digestion with compositions of the     72   Bethsaida phase reported by Casselman et al. (1995) confirm the discrepancy. For pulverizing, low chrome steel pulverizing equipment was used. Upper and lower detection limits (LOD) is in Appendix A5, Table A5.1.  4.3. Muscovite and chlorite chemistry from electron microprobe analysis 4.3.1. Muscovite major element compositions The bulk rock composition is an important constraint on the composition, alteration, mineralogy, and texture of muscovite and chlorite. Because of this influence, the mineral chemical data was grouped by the principal types of host rocks present: the Bethsaida phase intrusive host rock (granodiorite), the Bethlehem phase and the Guichon Variety (biotite-rich granodiorite and the hornblende-rich granodiorite, respectively). Muscovite samples from the Bethsaida phase (Bethsaida granodiorite) The potassium content in the muscovites from the Bethsaida phase is relatively consistent from the Alwin mine to the Valley pit and varies from 0.882 to 0.997 (pfu) which, as explained in Chapter 1, is close to the ideal muscovite composition. Total “K-site” in the muscovite, which is the sum of K+Ca+Na (pfu), is in the range of 0.906 to 1.051 for the Bethsaida granodiorite. However, Na varies considerably. The sodium content in the samples from the Bethsaida phase decreases in distance from the Valley deposit to the Alwin mine forming a trend. The muscovite is paragonitic (Na-bearing) in samples from the Valley deposit. Sodium varies from 0.0485 to 0.0890 pfu with a mean of 0.0736 pfu at the Valley deposit, whereas in the Alwin mine Na varies from 0.0147 to 0.0390 pfu with a mean of 0.0272 pfu (Figure 4.1). The exception in this trend is represented by sample HVD06 from the Valley margin. This sample differs from the nearby sample HVA01, which contains Na similar to the Valley deposit and fits the trend. Muscovite becames progressively enriched in Na with the increase of temperature (Guidotti and Sassi, 1976; Guidotti, 1984). Ca content is low, mostly under 0.010 pfu. In addition to Ca, Ba may be also incorporated into the interlayer cation site. Only half the electron microprobe analyses of Ba were above the detection limit between 0.0027 and 0.013 (max in Alwin mine). Silicon increases from 3.11     73   pfu (mean) in Valley deposit to 3.27 at the Alwin mine. Sample HVD06 falls outside the trend with distinctly higher Si content (mean 3.29 pfu). Sample HVD06 is a green muscovite of medium to fine grain size. Texturally, muscovite in HVD06 is pervasive but also replaces biotite, however there is no chemical difference between these two textural types. Sample HVA01 is gray-white muscovite and contains coarse pervasive muscovite similar to those found in the Valley deposit but coarser than those from sample HVD06. In Figure 4.1, the data are colored according to the sample location since they represent spatial variation, sample HVD06 is represented as inverted blue triangle (Figure 4.1).  Figure 4.1: Electron microprobe data of muscovite altering the Bethsaida phase. Values given per formula unit (pfu), the trend shows the best sodium distribution of Microprobe data in the Bethsaida phase. Data colored according to the location of the samples (see insert map). Red arrow shows the possible temperature relationship respect to the Na content; the temperature bein higher at Valley and lower at Alwin. Oxide percent values for Na less than the detection limit were considered as zero and are not plotted.     74   Looking at the octahedral site of the muscovite formula, if the Mg+Fe+Si content is plotted versus the aluminum cation total [Al 2+ VI  IV  VI  (tet)  +Al  (oct)  ] guided by the Tschermak  IV  substitution formula ((Mg, Fe ) , Si =Al , Al ; substitution of AlIV, AlVI by Mg and Fe see chapter 1), it is evident that the largest Tschermak substitution occurred in the samples from the Valley deposit. This substitution occurs to a larger degree in the Alwin mine than in the Bethsaida Zone and the Valley deposit. Muscovites from the Alwin mine, Bethsaida margin and sample HVD06 are more phengitic than those from Valley. Based on the limited samples analyzed, there may be also a smaller scale zonation of phengite and Na content in muscovites around the Bethsaida Zone with slightly elevated Na but lower phengite in muscovite from the Bethsaida Zone compared to sample from the Bethsaida margin (Figure 4.1 and Figure 4.2). Iron versus Mg shows a scattered plot and poor correlation overall but individual samples may show better correlation. For example, Alwin has higher Fe and Mg whereas Bethsaida Zone samples have generally higher Mg than Valley (Figure 4.3). Additionaly, HVD06 shows moderate to increase in Fe with strong increase in Mg (Figure 4.3A). Magnesium and Si have a slightly positive correlation trend from low Si and Mg values at Valley to higher but somewhat scattered Si and Mg values at the Alwin mine (Figure 4.3B). Additional elements such as Ti have similar concentrations across the entire transect and are mostly lower than 0.05 pfu. Manganese is relatively high Alwin and at the Bethsaida margin (HVD050) 0.004 pfu (mean) and low in the Valley deposit (0.0018 pfu mean). Fluorine is accommodated in the anion site of the muscovite formula (see Chapter 1), but is mostly below the detection limit; only 13% of the data (spots measured) are above the detection limit. Those analyses correspond to the samples of the Bethsaida Zone (max 0.1 pfu), HVD06 (max 0.11pfu) and the 1000-bench sample (HVD044) from the Valley deposit (max F content: 0.070 pfu). Since these values are low and close to detection limit they are not shown graphically. At the Valley deposit, samples HVD044 (770 bench Valley pit) and HVD049 (1000 bench Valley pit) show only minor compositional variation even though they differ in elevation. Potassium, Al, Na and Ba are constant in both samples. In the octahedral site,     75   elements such as Mn, Ti, Mg are also constant and only a slightly variation occurs with respect to Fe which is higher in 770-bench sample than in the 1000-bench sample. Since the chemistry of samples from the Valley deposit is relatively uniform, both samples are plotted using the same color (Figure 4.1, 4.2, 4.3).  Figure 4.2: Muscovites near the Valley deposit has a greater Tschermak (less phengitic component) than those in the Alwin mine (more phengitic). Samples from Bethsaida zone scatter between the two apparent end members. Legend comes from the inserted map in Figure 4.1.     76   A)  B)  Figure 4.3: Electron microprobe data in pfu for Fe and Mg in muscovite from the Bethsaida phase. A. Fe versus Mg shows no correlation. B. Mg versus Si shows a slightly positive correlation. Legend comes from the inserted map in Figure 4.1. Outliers with higher concentrations of Mg correspond to muscovite replacing biotite in sample HVD06. XRD analysis confirmed that this sample does not have any biotite left. Oxide percent values for Fe and Mg less than the detection limit were considered as zero and are not plotted.     77   Muscovite samples from the Bethlehem phase and the Guichon Variety (biotie granodiorite and hornblende granodiorite) Samples from the Bethlehem phase and Guichon Variety are colored and classified according the alteration zone where they are located (Figure 4.4). Potassium, Na and Ca at Bethlehem phase and Guichon Variety do not show significant variations compared to Bethsaida phase data. Sodium content is very low and relatively uniform from 0.01pfu to 0.04 pfu with few data points up to 0.16 pfu. Barium shows slightly higher concentrations in muscovite from the sodic-calcic alteration zones compared with those from the phyllic alteration. Silicon is higher than in the Bethsaida phase (3.19 to 3.38 pfu), with the highest pfu values present in samples from the distal phyllic alteration (sample G184 with Si ranging from 3.3 pfu to 3.38 pfu). In general, the interlayer substitution of the muscovites does not show significant trends with Na, Fe and/or Mg (Figure 4.5). In the octahedral site, different populations of data, albeit with large overlaps, may be representative of the alteration type. Thus, Mg-rich muscovites characterize the distal phyllic zone (0.21pfu mean) whereas relatively Fe-rich with moderate Mg characterize the intense phyllic zone and, relatively Mg-rich and Fe-poor muscovites correspond to the sodic-calcic alteration (Figure 4.5). Manganese is generally below detection limit with exception of the sample from the distal phyllic alteration (G184) where it can be up to 0.006 pfu. Chlorine values are mostly below detection limits, but some values may reach up to 0.0047 pfu. Fluorine values are also mostly below detection limit with the exception of few muscovites from the intense phyllic alteration where F varies from 0.045 pfu to 0.065 pfu. Titanium is low in the muscovites from Bethlehem and Guichon with a maximum of 0.011pfu and a mean of 0.0047 pfu.     78   Figure 4.4: Aerial photo with location of samples from the Bethlehem phase and Guichon Variety according to alteration type (see Table 3.3).     79   Figure 4.5: Muscovite data from Bethlehem phase and Guichon Variety colored according alteration type and symbolized by host rock. A. Sodium versus Si. B. Plot of Fe+Mg+Si versus Al cation total (Al (tet) + Al (oct)), black line represents the ideal Tschermak substitution line. C. Magnesium vs Fe plot with data from Bethlehem and Guichon muscovite.     80   Muscovite of the Bethsaida phase versus Bethlehem phase and Guichon Variety discussion The chemistry of muscovite has been treated separately (see above) since the host rock composition including the Bethlehem phase (biotite granodiorite) and Guichon Variety (hornblende granodiorite) are more mafic than the Bethsaida phase (granodiorite). Comparing muscovite chemistry of all the host rock types mentioned above in same plots, helps to demonstrate how muscovite varies spatially across the Alwin-Valley-Bethlehem transect (Figure 4.6). Overall, samples from the Valley deposits tend to be closer to the muscovite-paragonite end-member composition. The muscovites from Alwin mine (Bethsaida phase), Bethlehem phase and Guichon Variety are close to the muscovitephengite end member composition suggesting the limited effect of the host rock in the chemistry of muscovite. The total K-site content in the muscovite, which is the sum of K, Na and Ca are over 0.80 pfu, which imply that these number fall in the range of the muscovite compositon (Figure 4.6A). Another way to look at the subtitution in the K-site is using K/(K+Na+2Ca) ratio versus Al cation total (Figure 4.6B). This diagram reflects the paragonitic content in the muscovite; the lowest K content corresponds to samples with the most extensive Ca and Na substitution. The Na content is highest in samples from the Valley deposit whereas the Na content at Bethlehem and Guichon is low and uniform (Figure 4.6C). Consequently, the K content increases slightly at Bethlehem and Guichon compared to the Valley deposit since Na and K occupy the same crystal structural site in muscovite. Total Al content is higher in muscovite from the Valley deposit than in those from Bethlehem and Guichon. This reflects the greater Al substitution by Fe + Mg in the muscovite from Bethlehem, Guichon and Alwin (phengitic-muscovite) compared to those from the Valley deposit (Figure 4.6 D). In summary, muscovite chemistry reflects its location within the hydrothermal system and with it the alteration style. It also may reflect variations in host rock composition.     81   Figure 4.6: Major element variations in muscovite from Alwin, Valley and Bethlehem deposits (data are colored according to location not as alteration type). Outlier values correspond to dusty muscovite of the Bethlehem phase principally. A. K+Na+2Ca versus total Aluminum (Al6+Al4), solid line represents the muscovite end member formula. B. K/(K+Na+2Ca) versus Al cation total show the paragonite content in the muscovite. C. Sodium versus silica shows the sodium substitution. D. Fe+Mg+Si versus Al cation total. Zoom of the area where the bulk of the data plot (see inset diagram). Solid line represents the ideal Tschermak substitution line.     82   4.3.2. Chlorite major element composition Coarse chlorite with variable birefringence is pervasive in the Bethlehem phase and Guichon Variety (see Chapter 3). In contrast, chlorite is only present in two samples from the Valley deposit (see Chapter 3), therefore chlorite analytical data for Valley are not presented. Chlorite is part of the quartz-sulfide vein with muscovite assemblage but it is also associated with other mineral assemblages such as sodic-calcic or distal phyllic alteration. Electron microprobe measurements were performed on carefully selected chlorite grains and the most reliable data were selected after standardization (Table 4.2). When plotting data from chlorites according to the alteration assemblage, it is evident that Mg-rich chlorite is present mostly in the sodic-calcic, weak-moderately sodic-calcic and distal phyllic alteration zones, whereas Fe-rich chlorite is more common in the intense phyllic alteration assemblages (Figure 4.7). The outlier values in the trend shown in Figure 4.7 represent chlorite in sample BTA28 and BTA18 from the phyllic alteration of the Bethlehem phase and Guichon Variety respectively, which have considerable amounts of specular hematite. Sample BTA28, is cut by a specular hematite vein, whereas in BTA18 specular hematite is widespread. Iron content is better represented in Figure 4.8 that shows a map view of the Bethlehem deposits and the chlorite samples for which microprobe data were obteined. The data were classified in five groups of equal percentages and color coded in Figure 4.8. The most Fe-rich group is concentrated around the Iona pit and south east of Jersey pit. The high concentration of Fe in the phyllic alteration coincides with presence of specular hematite, which may indicate that chlorite incorporates Fe3+ in relatively oxidized conditions. However, all the samples from the phyllic alteration are associated with the specular hematite (see Table 3.3 in Chapter 3). For example, sample G178 has higher concentration of Fe but it does not have specular hematite or hematite. However, blue chlorite (description below) is abundant, which implies that the high Fe content in this sample comes from the blue chlorite and not from the specular hematite.     83   Potassium content in chlorite is below 0.012 pfu with a few outliers from 0.02 to 0.08 and a mean of 0.045 pfu. Potassium values above the detection limit are higher in chlorite of the phyllic alteration than in chlorites of the sodic-calcic and distal phyllic zones. Sodium is generally under 0.018 pfu in the phyllic alteration but a large percentage of the values are below detection limit. Calcium in chlorite is relatively uniform and low (commonly below 0.025 pfu, with outliers values from 0.03 to 0.23 pfu an a mean of 0.01 pfu). Approximately the 99% of the spot analyses for Ba were below the detection limit. Octahedral aluminum (AlVI) is slightly higher in chlorite of the phyllic alteration than in chlorite from the sodic-calcic and the distal phyllic alteration (Figure 4.9). On the other hand, Mg (Mg/(Mg+Fe+Mn)) concentration is higher in the chlorite from the distal phyllic, strong and moderate sodic-calcic alteration than that at chlorite from the intense phyllic alteration (Figure 4.9). Manganese is scattered ranging from 0.005-0.08 pfu with a mean of 0.027 pfu. Chromium is mostly below detection limit (with few maximum peaks of 0.0089 pfu). Titanium values are mostly below 0.016 pfu with outliers from 0.03 to 0.23 in the sodic-calcic and distal phyllic alteration. In the tetrahedral site, the Si content is moderately higher in the sodic-calcic alteration than in the phyllic alteration, contrary to the tetrahedral aluminum (AlIV). In the anion site (OH-site), elements such as F have values above the detection limit ranging from 0.065 to 0.108 pfu but mostly in the sodic-calcic and distal phyllic alteration. Chlorine is mostly below the detection limit, few outliers range from 0.004 to 0.005 pfu. Fluorine, chlorite and water (OH) sum eight in the anion site since the chlorite formula is based on 8 cations.     84   Figure 4.7: A. Magnesium versus Fe in chlorite from the Bethlehem phase and Guichon Variety shown according to alteration type. Dashed red line encloses microprobe values from two samples shown in B and C. B. Plane-polarized light photomicrograph of sample BTA28 showing pervasive muscovite (Mp) intergrowing with chlorite and specular hematite. C. Plane-polarized light photomicrograph of sample BTA18 showing specular hematite crystals and chlorite.     85   Figure 4.8: Aerial photo showing Fe distribution in chlorite from Bethlehem and Guichon samples. Electron microprobe data colored and divided in 5 equal ranges. Dashed orange line encloses Fe rich samples and matches the distribution of quartz-sulfide veins with muscovite-chlorite selvage (phyllic alteration samples), whereas blue, light blue and green are characterized by lower amounts of Fe. White dashed line separates the two types of host rocks in the area. Iron-rich chlorites are present in the eastern side of the Bethlehem mines largely within the Iona pit where phyllic alteration is most intense. Magnesium-rich chlorites are present in samples outside the mineralized cores in association with weak dusty muscovite and illite.     86   Figura 4.9: Mg/(Mg+Fe+Mn) versus AlVI/(sum Oct) of chlorite microprobe values from Bethlehem phase and Guichon Variety according to the alteration type. Sum Octahedral (Oct) is the sum of elements in the octahedral site (AlVI, Ti, Fe, Mn, Mg and Cr). Outlier values near the bottom of graphic correspond to the samples BTA18 and BTA28 with high concentration of specular hematite (see fig. 4.8). Oxide percent values for Mg, Fe or Mn less than the detection limit were considered as zero.     87   Chlorite composition compared to birefringence color Chlorite composition also varies according to the birefringence color at the Bethlehem phase, the Guichon Variety and the Valley deposit (Table 3.2-chapter 3). In a plot of Fe versus Mg, greenish chlorite has the highest Mg content whereas blue chlorite is richest in Fe (Figure 4.10). Brown chlorite from the Valley deposit has an intermediate Fe/Mg composition and plot in the middle of the trend.  Figure 4.10: Electron microprobe data showing chlorite composition relative to birefringence color. Iron versus Mg plot of Bethlehem phase and Guichon Variety shows greenish chlorites are higher in Mg whereas blue chlorites are higher in Fe (Bethlehem area:Biotite-granodiorite and Hornblende-granodiorite). Outlier dots in the lower right corner correspond to samples BTA28 and BTA18 rich in specular hematite (see Figure 4.7).     88   4.4. Muscovite and chlorite microprobe analysis compared with SWIR analysis Field portable short-wave infrared (SWIR) spectrometers are used to detect the compositional variation of hydrous minerals such as clays, micas, chlorites, talc, epidote, amphiboles and sulphates as well as carbonates (Jones et al., 2005). The measurement of wavelength position of the absorption feature for white micas (muscovite, phengite, paragonite, illite) is in 2200 nm (Al-OH) region (Clark, 1999), whereas chlorite has a Fe-OH absorption feature at about 2250 and a Mg-OH absorption feature at about 2350 nm. Thus variation in the mineral chemistry can be detected by a shift in the absorption feature for muscovite and chlorite (Thompson et al., 1999). In the white mica compositional range, the subtle variation in the wavelengths of the Al-OH absorption feature is principally controlled by the proportion of the major elements in the Al octahedral site in the muscovite structure. Thus, absorption features less than 2195 nm are characteristic for white micas with high Al and low Fe-Mg content; whereas wavelength more than 2216 nm represent white micas with lower Al content but higher Fe-Mg content (Jones et al., 2005). According to Post and Noble, (1993) and Herrmann et al., (2001), Na-bearing white micas (paragonite) have an absorption feature between 2190 nm and 2195 nm; K-bearing white micas (muscovites) between 2200 nm and 2228 nm; and Fe-Mg white micas (phengites) between 2216 and 2228 nm. However, Jones et al., (2005) suggest intermediate wavelengths for samples with white mica of intermediate composition. SWIR data are compared to electron microprobe data in a plot of Na versus Si (Figure 4.11A and Figure 4.13). It is replotted according to the absorption feature for muscovite (2200 nm) of the Valley deposit, Bethlehem phase and Guichon Variety. Similarly, a plot of Fe versus Mg is used to examine the absorption in the chlorite (2350 nm) from Bethlehem phase and Guichon Variety. The comparative plots are colored according to 5 equal ranges to generate a clear pattern of variability. Plots are separated for host rock types as it has been treated through this thesis and finally all data is plotted together. Additional XRD analysis in comparison with SWIR data for muscovite is presented in Appendix A1.     89   4.4.1. Electron microprobe versus SWIR data - muscovite Bethsaida phase In the Bethsaida phase, the SWIR data in muscovite varies with composition. Shorter wavelength (2200-2202 nm) corresponds to Na-rich muscovite from the Valley deposit (Figure 4.11A). Absorption wavelength increases up to 2203 nm in the Bethsaida Zone where the Na content decreases and to even higher wavelength (2206 nm) in the muscovite from the Alwin mine and Bethsaida margin, which have less Na and more Fe-Mg. The wavelength of 2205 corresponds to the sample HVD06 (referred in Figure 4.1) that correspond to a fine- to medium-grained green muscovite (see appendix A1, Figure A1.2). If only the K content is plotted against the absorption features (Figure 4.11B), the data have a scattered distribution, but some muscovite with low K contents correspond to those with higher absorption wavelength of the 2200 nm. However, if the two major components of the octahedral site of the muscovite structure, which are K and Na (Ca is negligible), are plotted (Figure 4.11C), then we can see the same tendency as shown in the Na versus Si diagram.     90      91   Figure 4.11: Probe data color coded by SWIR results for muscovite of the Bethsaida phase. Data colored according to 5 equal ranges in the 2200 nm wavelength absorption feature. A. Sodium versus Si shows lower wavelength represents Na rich muscovite. Higher wavelength represents Fe+Mg rich muscovite (phengites). B. Potassium versus Si shows a scattered plot. C. Potassium and Na versus Si shows similar tendency than in the Na versus Si diagram.  Bethlehem phase and Guichon Variety In the Bethlehem phase and Guichon Variety, electron microprobe analyses demonstrate a small variation for muscovite. Thus the SWIR data also shows a limited range of the principal absorption feature. Two examples are given in Figure 4.12 in which A and B show an scattered pattern without a clear trend in the 2200nm wavelength.     92   Figure 4.12: Probe data color coded by SWIR results for muscovite from the Bethlehem phase and Guichon Variety. Data colored according to 5 equal ranges in the 2200 nm wavelength absorption feature. A. Plot K+Na+2Ca versus Al cation total. B. Sodium versus Si.     93   Overall district A plot of Na versus Si (Figure 4.13) best represents the compositional variation of muscovite from the Alwin-Valley-Bethlehem transect and this is reflected in the SWIR wavelength ranges. At a regional scale, muscovite from the Valley deposits and the Bethsaida Zone, which are relatively rich in Na, have a shorter wavelength absorption feature from 2200nm to 2204nm, whereas the more phengite-rich muscovite from Alwin, Bethsaida margin and Betlehem deposits have the absorption feature at higher wavelength from 2205nm to 2209nm.  Figure 4.13: SWIR comparison between muscovite from Bethsaida and the Bethlehem-Guichon rocks. Solid black circle represent samples from Bethlehem phase and Guichon Variety inserted in the Bethsaida phase trend.     94   4.4.2. Electron microprobe versus SWIR data - chlorite Bethlehem phase and Guichon Variety In the Bethlehem phase and Guichon Variety, the SWIR data in chlorite reflect the compositional variation in Fe and Mg. Magnesium-rich chlorites have a shorter wavelength absorption feature at 2350nm whereas Fe-rich chlorites have the absorption feature slightly higher at 2350nm (Figure 4.14) consistent with the proposal by Pontual et al., (1997). Thus SWIR data of chlorite can potentially be used to map the variation in the host rocks, that is the Bethlehem phase and Guichon Variety. The exception is chlorite occuring with intense specular hematite (SpHm), which, as previously stated, affects the Fe content in the chlorite. SWIR data are also consistent with a higher Fe content of these chlorite.  Figure 4.14: Probe data color coded by SWIR results for chlorite from the Bethlehem phase and Guichon Variety. Data colored according to 5 equal ranges in the 2350 nm wavelength absorption feature. Chlorite affected by specular hematite (SpHm) plot in the lower right corner.     95   4.4.3. Discussion Short-wave infrared analysis (SWIR) can qualitatively distinguish chemical variations in muscovite and chlorite. An increase of Fe, Mg and Si in the muscovite is reflected in an increasing wavelength of the 2200 nm absorption feature. In addition, the depth of the absorption feature in the 1900 nm area for muscovite showed considerable change in depth depending on the Mg/Na ratio (see Apendix A1). The samples analyzed in this study contain dominantly muscovite (K-bearing “white mica”). Despite the subtle enrichment in Na at Valley deposit, the “white micas” are still muscovite and not paragonite. Thus, as suggested by Jones et al., (2005), Na-bearing muscovite from Valley have an absorption feature of (2200-2202 nm), which is between the absorption wavelength of pure muscovite (~2200 nm) and pure paragonite (~2195 nm), but closer to muscovite. The absorption feature of muscovite from Alwin (2206 nm) and Bethelehm (2205-2209 nm) are closer to pure phengite white micas, whereas the Bethsaida Zone (2200-2203 nm) lies in between of pure muscovite and phengite. Iron-rich chlorites have an absorption feature at higher wavelength at ~2350 nm, whereas this feature moves to slightly lower wavelength (~2341 nm) with higher Mg content. Thus, SWIR data may be used to map the Fe and Mg compositional trend of chlorite at Bethlehem.     96   4.5. LA-ICP-MS analyses 4.5.1. LA-ICP-MS data Laser ablation data for muscovites were obtained in samples where the muscovite content is high and where the grain size is large enough to permit separation of grains for the grain-mount technique (see methodology section above). Thus, only muscovite of the phyllic and potassic alteration zones has been selected; dusty muscovite from the sodic-calcic and distal phyllic alteration zones of the Bethlehem deposits were not analyzed by this technique. Laser ablation in thin section was done in one sample with three different textural muscovite types to determine any possible chemistry variation in trace element concentration. Chlorite analyses, using the grain-mount technique, has been obtained from the Bethlehem phase and Guichon Variety as chlorite is restricted in the Valley to Alwin area, being only present in the potassic alteration zones in the Valley deposit. LA-ICP-MS in thin section was also done in one single chlorite sample with several chlorite birenfringence colors. Elements showing systematic variations are presented in tables in this chapter. Refer to Appendix A4 for the complete data.  4.5.2. LA-ICP-MS results in muscovite Bethsaida phase In the Bethsaida phase Rb, Cs and B in muscovite are well correlated with Tl. Boron and Rb are positively correlated with Cs and Rb is also correlated with B (Figure 4.15 A and B). Rubidium, Cs, B and Tl content in muscovite increases with distance away from the Valley deposit (Table 4.3). In contrast, Li and Sr are negatively correlated with Cs, B, Rb and Tl. Lithium, Sr, Ti, Sn and V decrease with distance away from the Valley deposit and are most depleted near the Alwin mine (Figure 4.15 A,B,C,D; Table 4.3), the highest concentrations of these elements correlate with Na-bearing muscovite. Muscovites from sample HVD06 are anomalous in Ti and Zn. This sample has unusually high Ti contents probably due to rutile inclusions in muscovite grain type Mb (muscovite replacing biotite). Due to this possibility, Ti values in HVD06 may reflect contamination from fine-grained     97   intergrown rutile and are not considered further (Table 4.3). Zinc values increase moderately from the Valley deposit to Alwin, but the highest concentrations are found again in sample HVD06 from the Valley margin (Figure 4.15). Phosphorus content is low at Alwin, Bethsaida margin and Bethsaida Zone but higher at the Valley deposit. Tungsten is low at Valley deposit and Alwin but relatively higher at the Bethsaida Zone. Molybdenum is more scattered and only locally high values of up to 31.3 ppm have been recorded at Valley margin. Relatively high concentration of Cu are recorded in the muscovite from the Bethsaida Zone (sample HVD036), whereas Cu values in muscovite at the Valley deposit are mostly below the detection limit (Figure 4.15F). There is no systematic variation between 63  Cu and 65Cu and only the 63Cu values are plotted. Manganese is highest at the Alwin mine  (Figure 4.15 F). Cobalt has relatively high concentration at Alwin mine and low concentration in the Valley deposit and Bethsaida Zone. Barium values are variable for all areas in the Bethsaida phase (Table 4.3, detailed data in appendix A4), with the highest value of 1541 ppm recorded for the Valley deposit. The following elements show low concentrations or no systematic variation (not included in Table 4.3): Arsenic is very scattered and mostly under 2ppm, being slightly higher at the Bethsaida Zone (see appendix A4). Uranium has values very close to the detection limit throughout the sample set. Lead has only been detected in sample HVD06 from the Valley margin. Scandium is relatively low and uniform (mostly under 10ppm and two values around 70 ppm at HVD036-Bethsaida Zone and HVD06-Valley margin. Chromium shows no district scale systematic variation. Bismuth, Te, Se and Th show only scarce data above the detection limit in all samples and Se was not detected in any of the muscovite from the Alwin mine.     98   Table 4.3: Principal trace elements that show a lateral variation in muscovite from the Bethsaida phase.  The table summarizes the minimum (min), maximum (max) and mean from the detailed table give in the appendix; “n” is the number of data taken for the mean, “n” is smaller for Mo, Cu, Sr in some zones because some analyses were below detection limit in these elements. Limits of detection for stardard used in LA-ICPMS is in Table A4.1.     99   Figure 4.15: Trace element trend of muscovites in the Bethsaida intrusive phase. A. Boron is positively correlated with Cs. B: Rubidium is positively correlated with Tl. C. Lithium is negatively correlated with Cs. D. Strontium is negatively correlated with Tl. E. Zinc is positively correlated with B. F. Copper shows major concentrations in Bethsaida zone and Valley margin, whereas Mn has major concentrations in Alwin mine and Bethsaida margin. (Cu corresponds to the 63Cu).     100   Bethlehem phase and Guichon Variety Trace element analyses in muscovite from Bethlehem are from the phyllic alteration of the Bethlehem phase and Guichon Variety rocks. For this reason, the interpretation is based on the host rock type (Figure 4.16; see chapter 3). Elements showing a positive correlation are Rb versus Tl, V versus Ba, Co versus Mn and Cu versus Zn (Table 4.4, Figure 4.16). From these plots it is evident that Mn shows the best correlations in muscovite from Bethlehem phase and Guichon Variety. Manganese has also a positive correlation with Co, Cu, Zn, Cs and W (e.g. Figure 5.16 D). Vanadium and Ba show greater concentrations in muscovite from Bethlehem phase than the Guichon Variety (Figure 4.16 C) but this tendency is not well defined with other elements. Other trace elements (B, P, Sr, Sc, Sn) are scattered with no clear trend. Titanium variation is scattered but can reach higher concentrations up to 1056 ppm (in sample BTA28 of the Guichon Variety). Lithium variation is scattered with maximum concentration of 8.8 ppm. Chromium is scattered, normally below 15 ppm. Other elements with low concentration are U, Th, As, Bi (see appendix table). Molybdenum is normally at low concentrations except for sample BTA28 of the Guichon Variety (Table 4.4). Tellurium and Se are mostly below detection limit (see appendix table). In general, sample BTA18 has the highest concentrations of Pb, W, Sc, Cs, Co and Mn. In contrast sample G178 has the lowest content in the majority of the trace elements, both samples correspond to the Guichon Variety.     101   Table 4.4: Principal trace elements that show good correlation or significative concentrations in the muscovite from Bethlehem phase and Guichon Variety.  The Table summarized the minimum (min), maximum (max) and mean from the detailed table given in the appendix; “n” is the number of data taken for the mean, is smaller for W, Mo, Li, Sr and Tl in some muscovites because some analyses were below detection limit in these elements. Limits of detection for standard used in LA-ICP-MS is in Table A4.1.     102   Figure 4.16: Trace elements in muscovite from the Bethlehem phase and Guichon Variety rocks. All data correspond to muscovite of the phyllic alteration. A. Rubidium versus Tl with the lowest values in sample G178. B. Boron versus Cs showing the highest concentrations of Cs in BTA18 and lowest in G178. C. Vanadium versus Ba, showing higher concentration in these elements in Bethlehem phase rather Guichon Variety. D. Cobalt versus Mn shows a good correlation, highest Mn concentrations are in muscovite of BTA18. E. Copper versus Zn, plot show scattered behavior. F. Copper versus Ti, Ti increases over 600ppm mostly in muscovite from Bethlehem phase. Trace element values less than the detection limit were considered as zero.     103   4.5.3. Trace elements analysis in muscovite – thin section technique LA-ICP-MS in thin section was applied to sample HVD039 of the Alwin mine area of the Bethsaida phase. This sample was selected for laser ablation in situ as it has three textural muscovite types in one single sample (Mp= pervasive muscovite with size of the grain 0.1mm-0.4mm muscovite; Mc= coarse muscovite, with size of the grain 0.4mm-1mm; and Mb= muscovite replacing biotite with variable size of the grain) and because of the coarsegrained nature of this sample. LA-ICP-MS analysis on thin section was applied using the same spot diameter of 100µm for the three types of muscovite. Electron microprobe analysis showed the major elements concentrations of different muscovite types of this sample did not vary according to the textural type. However, LAICP-MS analysis showed that concentration of Li, Sc, Ti, V, Rb, Cs and Sn vary systematically depending on muscovite type. These elements are present at higher concentrations in coarse muscovite or in muscovite replacing biotite than in a pervasive muscovite (Figure 4.17). It might be considered that this variation in trace element concentration is related to the composition of the original mineral replaced by muscovite. However, this probably had little effect because some variation of the trace element can be seen in coarse versus fine grain muscovite both replacing plagioclase phenocrysts. Therefore changes in muscovite composition reflect several fluid stages, with different composition that generated coarse and fine grained muscovite.     104   Figure 4.17: Trace element data in three textural types of muscovite from sample HVD039 (Alwin mine). A. Rubidium versus Sn. B. Vanadium versus Li. C. Scandium versus Cs. D. Titanium versus Cs.  4.5.4. Discussion of LA-ICP-MS data for muscovite (Bethsaida phase –Bethlehem phase – Guichon Variety) Laser ablation analysis in muscovites from the Bethsaida phase, Bethlehem phase and Guichon Variety has been treated separately as the host rocks influence the chemistry and texture of muscovite. Trace element concentration in muscovite from the Bethsaida phase exhibit lateral variations in the Alwin mine to the Valley transect (Figure 4.18). Titanium, Li, Sn, V and Sr have higher concentrations in the muscovite of the Valley deposit than in those from Alwin and Bethsaida margin. Conversely, Tl, Rb, Cs, B, Mn, Co and Zn have higher concentrations in the muscovite from Alwin mine and Bethsaida margin, which are more phengitic muscovite.    105   The major and trace elements that can substitute in the structure of the muscovite are reviewed in Chapter 1. Elements, such as Tl, Rb, Ba, Cs and Sr, substitute for potassium in the interlayer site, and thus they exhibit good correlations between each other in the analyzed samples from Highland Valley. The exception is Ba, which is more scattered with slightly higher concentration in muscovite from Bethlehem deposits than at Valley. The correlation between Rb and Tl observed in all areas studied herein can be explained by the almost identical ionic radii and similar chemical properties (Ahrens, 1948). Manganese, Cr, Ti, Li and V are common trace elements substituting for Al and/or Mg or Fe in the octahedral site. Manganese has a good positive correlation with Co, Cu, Zn, V, W and Sc specially in muscovite from Bethlehem phase and Guichon Variety. This observation suggests that elements with valence +2 can substitute for Mn in the octahedral site. Similarly Co and Zn may substitute for Al, Fe and/or Mg in the octahedral site (Tiller and Hodgson, 1962) as probably Cu does. Scandium substitutes for major elements such as Al and Fe+3 of ferromagnesian minerals. However, Sc in the muscovite studied herein from Highland Valley is low in most samples. The exception is in the Valley margin (HVD06) and HVD036 from the Bethsaida Zone where Sc content is up 70 ppm. In the tetrahedral site, elements such as B can substitute for Al. Other elements such as Te, Th, Se, U or Te can be important trace elements in muscovites from other types of environments such us pegmatites. At Highland Valley, only a few concentrations of these elements are above the detection limit. Tin concentrations are moderate to considerable at Highland Valley, Sn rich muscovites have been related to Fe3+ in barren pegmatites in Sweden (Smeds, 1992).     106   .  Figure 4.18: Aerial photo showing summary of the trace elements in muscovite from the Bethsaida intrusive phase. Titanium, Li, Sn, V and Sr are present at higher concentrations in muscovite from the Valley deposit than near Alwin and Bethsaida Zone. Thalium, Rb, Cs, B, Mn, Co and Zn have higher concentrations in muscovites from Alwin than Valley and Bethsaida Zone.     107   4.5.5. LA-ICP-MS results in chlorite Seven samples across Bethlehem phase and Guichon Variety were selected for laser ablation, six by grain-mount method and one by thin section method. Trace elements in chlorite show more scattered patterns compared to muscovite and large overlaps if plotted according to alteration type. However, Mn, Zn and Li show good positive correlations between each other. These elements substitute in the octahedral site of the chlorite structure. An example is given in a plot of Li versus Zn (Figure 4.19 A; Table 4.5), in which the highest concentration of Zn corresponds to the phyllic alteration samples with the exception of a few low concentrations for sample BTA16 (sample that has the highest concentration in Rb, Ba and B) (Figure 4.19). The lowest Zn and Li values occur in chlorite replacing amphibole in areas of the weak to moderate sodic-calcic alteration. Similarly, Li has highest concentration in the chlorite from the phyllic and strong sodic-calcic alteration. A plot of Mn versus Co shows a similar trend, in which Co shows the highest concentration in the chlorite from Guichon Variety (sample G178) (Figure 4.19 B). Copper and Mo show different behavior (Figure 4.19 C). Chlorite associated with strong phyllic alteration is copper-rich and chlorite associated with weak phyllic alteration, overprinting the weak sodic-calcic alteration, is Mo-rich. This might be related to Mo anomalies peripheral to copper mineralization zone. Vanadium and Ti are relatively abundant (Table 4.5) but scattered. Other elements have lower concentration and limited compositional range. These include: Cr, Cs, Sr, Ba, Bi, Tl, As, Th and Sn (see Table 4.5). Tungsten is variable with the highest concentrations in sample G178 (phyllic alteration from Guichon Variety). Lead and U are mostly below 10 ppm, with the highest peak in sample BTA20 (weak to moderate alteration from Guichon Variety). Tellurium and Se were mostly below detection limits (see Appendix A4).     108   Table 4.5: Principal trace elements that show good correlation or significative concentrations in the chlorite from Bethlehem phase and Guichon Variety.  The Table summarized the minimum (min), maximum (max) and mean from the detailed table given in the appendix; “n” is the number of data taken for the mean; “n” is smaller for Li, B, P, Ti, Cr, Cu, As, Rb,Sr, Mo, Sn, Cs, W, Pb, Bi, Th, U and Tl in some chlorite because some analyses were below detection limit in these elements. Limits of detection for stardard used in LA-ICP-MS is found in Table A4.1.     109   Figure 4.19: Trace element in chlorite from the Bethlehem phase and Guichon Variety. A. Lithium and Zn in chlorite is highest in the phyllic alteration, where highest Fe content is observed (see Figure 4.8). B. Copper in chlorite is variable in the phyllic and strong sodic-calcic alteration areas. Molybdenum in chlorite is variable at the weak sodic-calcic alteration area.     110   4.5.6. Trace elements according to birefringence chlorite color of the Bethlehem phase and the Guichon Variety Chlorite composition also varies according to the birefringence color (see also Chapter 3; Table 3.2). However, the trace elements do not clearly show this systematic compositional trend. Only the Zn concentration seems to vary with the birefringence color (Figure 4.20A and B). Blue chlorite from the Bethlehem phase and Guichon Variety have slightly higher Zn concentrations than brown-green chlorite whereas dark chlorite (replacing amphibole) has the lowest concentration of Li and Zn and is the chemically most distinctive chlorite type. Thus, Zn-rich chlorite is also rich in Fe since blue chlorite shows higher Fe concentration than the green-brown chlorite, which is Mg-rich (see Figure 4.10). Additionaly, a comparative plot of Zn/Li versus Fe/Mg shows that higher concentrations of Zn in blue chlorites of the phyllic zone correlates with higher Fe content (Figure 4.10B). However, the sample BTA20 (Guichon Variety sample; LA-ICP-MS - thin section methodology), shows that the highest concentrations of Ba and Sn are in the dark chlorite (replacing amphibole) rather than the blue or green chlorite (replacing biotite). In this sample, P, Sr, Rb, Th and Tl show scattered behavior among the three chlorite types, whereas Ti, V, Cr, Mn, Sc, Co, Sn, Cu, Zn, As, Pb, Cs and W were higher in the green to brown chlorites than the dark chlorite (Figure 4.21).     111   Figure 4.20: A) Zinc versus Li trace elements in chlorite according to the birefringence color (samples from the Bethlehem phase and Guichon Variety). Black circle represents high Zn concentration. B) Plot showing average laser ablation data of the ratio Zn/Li versus average data of microprobe Fe/Mg ratio. Blue chlorite from phyllic alteration shows higher concentrations of Zn and Fe than brown, blue or dark chlorite of the strong sodic-calcic alteration; np=mean of microprobe data, nl=mean of laser ablation data.     112   Figure 4.21: Trace elements concentrations of chlorite from sample BTA20 (Guichon Variety) according to birefringence color. A. Barium versus Sn shows positive correlation, higher concentrations of Ba and Sn in dark chlorite and low in the blue chlorite. B. Uranium versus W shows a positive correlation, higher concentration of these elements occurs in the green chlorite rather dark chlorite. C. Uranium versus Pb shows a positive correlation in which Pb has higher concentration in green chlorite rather dark chlorite.     113   4.5.7. Trace elements versus aluminum concentration in chlorite The averages of octahedral Al (from microprobe data) versus trace elements of chlorite from the Bethlehem and Guichon samples show a clear variation according to alteration type (Figure 4.22). The ratio Alvi/sum octvi from the phyllic alteration range from 0.20756 to 0.2113 pfu, in the weak sodic-calcic alteration varies from 0.2047 to 0.2054 pfu, whereas in the strong sodic-calcic alteration varies from 0.1984 to 0.2004 pfu. In contrast most trace elements do not show a systematic variation with alteration type.  Figure 4.22: Examples of some trace elements in chlorite with respect to the aluminum content in the octahedral site (from microprobe average data); Alvi =octahedral aluminum; sum octv= sum of the total octahedral site (Alv, Ti, Fe, Mn, Mg, Cr, Ca, Na, K, Ba); Alvi/sum octvi >0.2075 correspond to the rocks of the phyllic alteration (acid conditions), whereas Alvi/sum octvi < 0.2054 correspond to the weak and strong sodiccalcic alteration alteration (neutral conditions). No clear correlation between Zn, Ba, Mo and Cu with Al site occupancy can be observed     114   .  4.5.8. Discussion of LA-ICP-MS data for chlorites (Bethlehem phase-Guichon Variety) Chlorite, from the Bethlehem phase and Guichon Variety show scattered trace element distribution. However, Zn shows a good correlation not only with Li and Mn, but also with Fe. The highest concentration of Zn is present in the phyllic alteration (Figure 4.19). Cobalt shows a similar association. Trace elements, Mn, Zn, Li and Co, substitute in the octahedral site of the chlorite, which explains the correlation among these elements. The blue birefringence color of chlorite from the Bethlehem phase and Guichon Variety is not a consequence of the Cr content (Kerr, 1959). The correlation of birefringence and Zn content may reflect the Fe content (see Figure 4.10). The concentration of Cu in chlorite varies widely in phyllic and Na-calcic alteration probably reflecting the effects of precursor alteration styles. Molybdenum concentration, on the other hand, is variable but generally higher in the weak sodic-calcic alteration reflecting samples outside of the Cu zones. In general, most of the trace element concentrations are higher in blue and green chlorites (chlorite replacing biotite) than in the dark chlorites (chlorite replacing amphiboleBTA20). Additionally, the substitution of Al in the octahedral site can reflect the acidity of the fluid. Aluminum variation in Highland Valley has also been noted in the porphyry Cu system at Yerington in Nevada-USA (J.H. Dilles, 2010, pers. comm.). The acidity of the fluid is reflected by the octahedral site occupancy in the chlorite structure. The ratio Alvi/sum octvi of less than 0.2 is typical for neutral conditions whereas Alvi/sum octvi higher than 0.2 reflects more acidic conditions. Around the Bethlehem deposits (Bethlehem and Guichon rocks) the absolute values for this ratio differ slightly from those at Yerington but show the same relative tendency. The ratio Alvi/sum octvi higher than 0.207 in the phyllic zone reflect the more acid conditions and whereas values lower than 0.205 reflect the more neutral pH conditions at the sodic-calcic alteration.     115   4.6. Whole rock geochemistry at Highland Valley Whole rock geochemical analysis was performed on 204 rocks across the Highland Valley district, in the transect Alwin-Valley-Bethlehem deposits. The objective was to recognize large-scale patterns of zonation and locally compare the mineral chemistry described above with the whole rock geochemistry (WRG). 4.6.1 Compositional variability in host rock The following section presents the variability of the elements according to the three host rock types recognized in the transect Alwin-Valley-Bethlehem deposits. Figure 5.16 shows Ti, P, Y, Th, Mg and V, which form a positive trend against Sc and reflect geochemical variations in compositional element groups. A similar pattern is observed with respect to Nb and Co (not shown in figure). In the Guichon Variety, which is a more mafic host rock than the Bethlehem and Bethsaida phase, Nb, P, Co, Ti, Sc, Y, Th, Mg and V are generally highest, whereas in the the most felsic Bethsaida phase, these elements are generally present at lower concentrations. An exception occurs with V (Figure 4.23F) in which a group of data from the Bethsaida phase lies out of the linear correlation with Sc. This high concentration of V belongs mainly the strong coarse muscovite alteration of the Valley deposit and part of the phyllic alteration of the Bethsaida Zone samples. This correlates with high V concentration in muscovite from the Valley deposits according to the laser ablation data (Figure 4.18). Comparing the least altered samples with the entire data set (Figure 4.23), it is evident that Ti, Sc, Y were not mobile during the alteration. These elements are generally considered immobile in hydrothermal systems (Finlow-Bates and Stumpfl, 1981).     116   Figure 4.23: Geochemical variations showing compositional element groups in the Guichon Creek Batholith (cross-section Alwin-Valley-Bethlehem deposits). A. Magnesium versus Sc. B. Thorium versus Sc. C. Yttrium versus Sc. D. Phosphorus versus Sc. E. Titanium versus Sc. F. Vanadium versus Sc. Open circles indicate least altered samples of each igneous host rock type. Solid circle represent anomalous V values of strong muscovite concentration from the Valley deposit and part of the Bethsaida Zone.     117   4.6.2. Alteration influence on alkali element concentration One way to represent the degree of mobility of the alkali elements is using the K/Al molar versus (2Ca+Na+K)/Al molar ratio (Graham et al., 1995) (Figure 4.24). The altered samples, corresponding to the Valley deposit (Bethsaida phase) trend towards K-feldspar and biotite alteration. These samples have large amounts of coarse muscovite as part of the potassic alteration at the Valley deposit (see chapter 3). Muscovite-rich samples (Mp, Mc, Mb; see detailed textural definition Table 3.1; chapter 3) have a tendency towards the Kbearing mica alteration corner, whereas the samples with only minor muscovite (Md) fall in the albite-plagioclase zone, which represents the relative depletion of K in the Bethlehem phase and Guichon Variety (sodic-calcic alteration zone).  Figure 4.24: Molar ratio plot showing projected alkali composition diagram according to the host rock type in Highland Valley. Square symbols represent samples used for electron microprobe and LA-ICP-MS analytical analysis. Empty circles represent least altered rocks. The red arrow represents the alteration trend of the muscovite rich samples towards the K-bearing mica. Dashed red line encloses all the samples taken in the Valley deposit. These samples exhibit evidence for potassic alteration. After Graham et al., 1995. KS (Kfeldspar), Bt (biotite), Kln (kaolinite), Chl (chlorite), Ab (albite), Plg (plagioclase), K-mica (potassic mica), Ilt (illite).     118   4.6.3. Comparison of LA-ICP-MS and whole rock geochemistry Comparison was made between the composition of host rocks and muscovite or chlorite within the same sample.  In the case of the Bethsaida phase, different colors  correspond to the muscovite from the Valley deposit, the Bethsaida Zone, the Bethsaida Zone margin and the Alwin mine (Figure 4.15). For the Bethlehem phase and Guichon Variety rock samples both muscovite and chlorite were separated according to host rock type for the interpretation. This comparison is useful to determine which are the elements that concentrate most in the muscovite or chlorite structure. Bethsaida phase Trace elements in muscovite of the Bethsaida phase such as Cs, Rb, Tl and V to a lesser extent Sr, Li and Co show a correlation with the whole rock geochemistry (Figure 4.25). Muscovite faithfully tracks whole rock compositions for these elements but not for others whose major sites are other minerals (Table 4.6).     119   Figure 4.25: Muscovite versus whole rock trace element geochemistry from Bethsaida phase in ppm. A. Rubidium. B. Cesium. C. Thalium. D. Lithium. E. Vanadium.     120   Bethlehem phase and Guichon Variety Comparing trace elements in chlorite and muscovite in the Bethlehem phase and the Guichon Variety where chlorite is abundant, shows that Zn, Co, Mn and Li are more concentrated in chlorite compared to muscovite and the whole rock. Thus, Zn, Li, Co and Mn in the whole rock maybe controlled by the amount of chlorite in the rock, where sulfide content is low. In contrast, Ba, Cs, Rb and Tl have higher concentrations in the muscovite than in the chlorite and whole rock geochemistry, indicating that these elements enter the muscovite structure (Figure 4.26). Strontium shows a higher concentration in the whole rock geochemistry than in the muscovite and chlorite. Cu only exhibits higher concentration in the chlorite than in the muscovite, but there is no clear relationship with respect to the whole rock geochemistry. Vanadium in chlorite forms a positive correlation with V in the muscovite suggesting these are the major hosts in the whole rocks. In summary, elevated concentrations of Zn, Li, Co and Mn in whole rock geochemical data indirectly indicate that considerable amounts of hydrothermal chlorite are present in the rock. Likewise, elevated Ba, Cs, Rb and Tl concentrations may indicate muscovite alteration.     121   Figure 4.26: Muscovite (purple) and chlorite (green) versus whole rock trace element geochemistry in ppm from Bethlehem phase and Guichon Variety (biotite rich granodiorite and hornblende rich granodiorite, respectively). A. Zinc. B. Cobalt. C. Lithium. D. Manganese. E. Cesium. F. Thalium.     122   4.6.4. Bethsaida phase, Bethlehem phase and Guichon Variety muscovite-chlorite comparison If we compare the trace element concentrations versus the whole rock geochemistry in muscovite across the entire Alwin-Valley-Bethlehem transect, only Cs and Rb show a good positive correlation (Figure 4.27). Tl is well correlated in the Bethsaida phase but not in the Bethlehem phase and Guichon Variety rocks (Figure 4.27, Table 4.6). Additionally, concentrations of Tl, Rb and Cs are approximately three times higher in muscovite than in whole rocks, which suggests that muscovite is a significant host of these elements. A comparison of trace element concentrations in chlorite with whole rock geochemistry across the three host rock types also shows correlations. Cobalt shows a good positive correlation with the whole rock geochemistry in the three types of host rocks similar to V. The exception is the sample G131 from the Guichon Variety, which does not fit in the trend. Cesium only shows a positive correlation in Bethlehem and Guichon rocks but not in the chlorite from the Valley deposit (Figure 4.28, Table 4.7). However, Cs concentrations in chlorite are equivalent to the whole rock geochemistry indicating that Cs is more dominant in muscovite. Cobalt is considerably higher in chlorite than in the whole rock chemistry suggesting that it is chlorite controlled. Vanadium is more concentrated in chlorite and muscovite of Valley than in the whole rock, indicating that this element is controlled by the proximal location of muscovite and to a lesser extent by chlorite abundance. Table 4.6: Comparative table of trace element concentrations in the muscovite versus whole rock geochemistry (WRG) from the transect Alwin-Valley-Bethlehem deposits.     123   Table 4.7: Comparative table of trace element concentrations in muscovite and chlorite versus whole rock geochemistry (WRG) from Bethlehem phase and Guichon Variety.  Figure 4.27: Muscovite versus whole rock trace element geochemistry in ppm from the Bethaida phase, Bethlehem phase and Guichon Variety. A. Thalium trace element versus Tl geochemistry. B. Cesium C. Rubidium.     124   Figure 4.28: Chlorite versus whole rock trace element geochemistry in ppm from the Bethaida phase (Valley deposit), Bethlehem phase and Guichon Variety. A. Vanadium. B. Cobalt. C. Cesium.     125   CHAPTER 5 Conclusions The major and trace element compositions of muscovite and chlorite across the Highland Valley district from the inactive Alwin Mine on the west, through the Bethsaida zone and nearby Valley deposit to the cluster of porphyry deposit at Bethlehem show systematic lateral variations (Figure 5.1 and Figure 5.2). These spatial variations in muscovite and chlorite chemical composition reflect the variability in the temperature and acidity of hydrothermal fluids within and between these deposits. The district is divided into two parts based upon host rock composition. On the west are deposits hosted in the Bethsaida phase of the Guichon Creek batholith; these include the Alwin veins system and the Valley porphyry Cu-Mo system, which represent separate and distinct hydrothermal centers. Adjacent to the Valley deposit is the low Cu-grade Bethsaida zone, which may represent still a third hydrothermal system as suggested by a chargeability anomaly (Casselman et al., 1995) and by the alteration intensity and textural characteristics as well as the variations in muscovite chemistry.  In contrast, host rocks to the Bethlehem  porphyry cluster (Huestis, Jersey and Iona deposits) are slightly more mafic. Moreover, extensive Na-Ca alteration derived from circulating non-magmatic fluids (Dilles and Einaudi, 1992) overprints the potassic and phyllic porphyry alteration. The more mafic host rocks and differing alteration history distinguishes the Bethlehem deposits from the Valley-BethsaidaAlwin system. These differences also affect the chemistry of muscovite and chlorite to some extent.  5.1. Muscovite chemistry The homogeneity of the rock of the Bethsaida phase (Alwin-Bethsaida-Valley) minimizes the effect of host rock composition on hydrothermal mineral chemistry. Hence, variation in muscovite chemistry directly reflects hydrothermal processes. Muscovite is the dominant mineral in the selvage of quartz-sulfide veins whereas chlorite is subordinate. Coarse-white muscovite from the Valley deposit has higher concentrations of Na and, thus, is     126   more paragonitic (ca. 0.6%Na2O, 0.08%MgO). This muscovite also has detectable halogens (F, Cl). The Na-rich muscovite together with K-feldspar and Na-plagioclase indicate high temperature of formation from a largely magmatic fluid (Brimhall, 1977; Muñoz, 1984). In contrast, muscovite from the margin of the undeveloped and low-grade Bethsaida Zone and the historically producing Alwin mine (4 km away from the Valley deposit) contains less Na and are phengitic (ca. 0.2wt%Na2O, 1.29wt%MgO) reflecting the Tschemark substitution [(Fe,Mg)2+ (Si)4+ = (Altet)3+(Aloct)3+]. These compositional changes between system reflect differing fluid temperature and more pH conditions. Within the Valley and Bethsaida zone, muscovite becomes more phengitic and contains less Na toward the margin of the hydrothermal system, reflecting decreasing temperature and more neutral pH conditions. The Alwin mine has similar muscovitic compositions to those found at the margin of the Valley deposit and Bethsaida zone. Within the Valley-Bethsaida-Alwin system, the numerous muscovite textural varieties are indistinguishable chemically in the major elements and therefore the chemistry of these elements only reflects the location of the muscovite within the porphyry system. However some trace element such as Rb, Sc, V, Li, Ti, Sn and Cs show slight differences in concentration depending upon protoliths for the muscovite.  For example, coarse and  pervasive muscovite replacing plagioclase or biotite, have slightly different trace element contents. The variation in trace elements could reflect either different fluid stages or just as likely chemical differences inherited from the original mineral replaced by muscovite. Despite the local variations, the chemical variations of the muscovite overall are consistent with changes in physiochemistry across the hydrothermal system(s) and in particular reflect a decline in temperature and increase in pH of the fluid from Valley to the Bethsaida Zone to the Alwin mine. Muscovite composition also tracks the solubility and mobility of some elements. Titanium and Sn are generally not very soluble and only are mobile in a relatively high temperature but low pH fluid. Their presence in muscovite likely reflects the original protoliths mineral that was replaced. On the other hand, alkalies (Cs, Rb), Tl and transition metals (Mn, Zn) are mobile at moderate pH and at lower temperature (Chaffee et al., 1976; Finlow-Bates and Stumpfl, 1981; Hastie et al., 2007). Cesium, Rb, and Tl elements increase     127   in concentration in the muscovite from Valley, to Bethsaida, and finally to Alwin. Similar changes are seen in in the whole rock geochemistry, which indicates that muscovite is the mineral hosting these elements within the porphyry system. The chemical variations recorded in the major and trace elements in the muscovite are partly reflected in the SWIR spectra in the muscovite from the Bethsaida phase. Sodium-rich muscovite has a lower absorption wavelength of 2200 nm to 2202 nm whereas phengiticmuscovite has a higher absorption wavelength of 2205 nm to 2206 nm. Thus, SWIR data can be used as a proxy to estimate the relative Na content in the muscovite in Highland Valley, as Na likely substituted for K in the muscovite. Although the host rock is different from the Bethsaida phase, the muscovite in the more mafic Bethlehem phase and Guichon Variety hosting the Bethlehem deposits fit the overall variations mapped in the Valley-Bethsaida-Alwin transect. Similar to the muscovite from the Alwin mine and Bethsaida margin, muscovite from the Bethlehem deposits is more phengitic than those from Valley. The phengite content in the muscovite from Bethlehem also indicates more neutral pH, and potentially lower temperature of formation than at the Valley deposit as suggested by John et al. (2010) (Figure 5.1). However, in contrast to the Valley deposit and Bethsaida zone, distal white mica at Bethlehem is illitic in composition, and not the higher temperature muscovite. Trace elements such as Tl, Rb, Cs, B, Co in muscovite from Bethlehem show similar variations in concentrations to those from Alwin and Bethsaida margin, whereas these elements are considerably lower in muscovite from the Valley deposit (see Table 4.3 and Table 4.4 in chapter 4). Manganese and Zn are present at lower concentration in muscovite from Bethlehem than in those from Alwin but muscovite from Valley is similar. Thus, absolute concentrations of these elements are probably controlled by the host rock, but variations likely reflect variations in fluid composition. SWIR spectra of muscovite from Bethlehem have, like those from Alwin and Bethsaida margin, an absorption wavelength of 2205 nm to 2209 nm indicative of low Na but high Fe and Mg content. The variability in the chemistry of the muscovite shows similar pattern to the east (Betlehem deposits) and to the west (Alwin mine) from Valley. This likely reflects the     128   characteristics of the individual hydrothermal systems rather than the influence of the host rock.  5.2. Chlorite chemistry Chlorite is not uniformly present across the Alwin-Valley-Bethlehem deposits as the selvages of quartz-sulfides veins cutting the Bethsaida phase generally lack chlorite. The lack of chlorite is inferred to be due to the more felsic and Fe-poor composition of the Bethsaida phase. Nonetheless, chlorite is common in the Bethlehem deposits, reflecting the more mafic host rocks. There, a zonation of the Fe content is mapped with Fe-rich chlorite related to intense muscovite-chlorite alteration (phyllic alteration), whereas Mg-rich chlorite is mostly associated with quartz-sulfide veins with dusty muscovite and chlorite selvages outside the mineralized cores or where intense epidote-chlorite (Na-Ca) alteration is present. Fe-rich chlorite, which generally has blue birefringence, has higher concentrations of Zn. Slightly higher concentrations of Sn and Ba are present in dark chlorite that directly replaces igneous amphibole, which suggests these elements are controlled by the precursor mineral. Fe-rich chlorite also contains a greater content of octahedral Al, which represents a more acidic environment than the surrounding Mg-rich but octahedral Al poor chlorite (J.H. Dilles, 2010, pers. comm.). This observation is consistent with the hydrolytic mineral assemblage of muscovite-chlorite (phyllic), which is superposed in the Bethlehem deposits on the higher temperature K silicate alteration. Chlorite also incorporates trace elements such as Li, Zn, Mn and Co, an observation also noted at Yerington (Cohen, 2011).  Rocks with elevated  concentrations of these elements may indicate chlorite-rich alteration. Chlorite shows a variation in the SWIR spectra at the 2350 nm absorption feature. Iron-rich chlorite has a higher wavelength at around 2349 nm whereas the Mg-rich chlorite has shorter wavelengths from 2341 nm to 2348 nm. However, the presence of Fe-oxides, reflecting potentially excess Fe, will affect the wavelength as Fe-rich chlorite associated with specular hematite has an absorption feature also at 2341 nm. For chlorite, the associated mineral appears to complicate an apparently simple relationship.     129   5.3. Implications of muscovite and chlorite chemical variations Hydrothermal fluids associated with porphyry Cu deposits are two-fold. One is the high-temperature fluid exsolved directly from the crystallizing magma chamber and rises buoyantly. Water – rock interactions and cooling will change the fluid. Cooling changes the fluid composition to more acidic compositions whereas water-rock interaction buffer the fluid toward more neutral pH, particularly in the feldspar-dominated rocks found at Highland Valley. The second fluid is the thermally driven external fluid present in the rocks. Where chloride-bearing fluids are present, significant Na-Ca alteration is possible leading to wholesale compositional changes in the rocks (Dilles and Einaudi, 1992). This is the case for the Bethlehem deposit, whereas Na-Ca alteration is only recognized on the fringes of the Valley and Bethsaida zone systems. Thus, the mapped changes in the muscovite and chlorite composition documented herein must reflect the competing hydrothermal processes superposed upon original differences in host rock. Sodium can substitute for K in muscovite at high temperatures (Brimhall, 1977 and references therein). Thus, change in Na content mapped within the Valley deposit from higher concentrations in the core to lower concentrations on the margin can be simply interpreted as changes in temperature. The higher temperature inferred for the core of the porphyry system is consistent with the observation of coarse-grained muscovite intergrown with K-feldspar at Valley. Muscovite here may be part of the high temperature potassic assemblage of quartz-biotite-K feldspar-muscovite or, alternatively may indicate a transition between potassic and phyllic alteration assemblages, but it is not part of an overprinting intermediate temperature phyllic alteration. However, the late and Na-poor, pale green and phengitic muscovite represented by sample HVD-06 likely is part of a phyllic overprint onto the higher temperature potassic alteration. The lack of significant Na in the muscovite at Alwin indicates that that chalcopyrite-bornite bearing vein system is a lower temperature system. Within the Valley and Bethlehem porphyry systems, the Fe-Mg contents of muscovite vary from the center or areas of high temperature alteration toward the periphery of the center.  This change is also evident in the low-Cu grade Bethsaida zone, which lends  credence to the hypothesis the zone represents a distinct hydrothermal center. The change in    130   muscovite chemistry toward more phengitic compositions outward toward the margin must reflect variations in pH, presumably due to the capacity of the rock to buffer the hydrothermal fluid. At Bethlehem, the distal white micas are illitic in composition, an observation that reflects decreasing temperature outward from the core of the porphyry Cu systems. Cohen (2011) reports similar variation in white mica chemistry from the core to margins of the Yerington system in Nevada. Overall, a trend to more phengitic micas applies to the Valley-Bethsaida-Alwin transect on the whole. The Alwin deposit, which is a small vein system, has many of the same textural features noted in the Valley deposit, with pervasive muscovite containing chalcopyrite and bornite, a sulfide mineral assemblage that characterized the potassic core at the Valley. Why the Alwin system is phengitic, and therefore reflecting more neutral pH conditions, is unknown. It simply could be the effect of different depths, as the Alwin mine sits at a slightly higher elevation than does the Valley deposit. However, there is little difference in elevation between the Bethsaida and Alwin systems.  Clearly there is a  difference in temperature of the two systems in view of the difference in the paragonitic component in the muscovite. Whether this observation suggest that the Alwin vein may represent the upper parts of a still deeper porphyry system similar to the Valley deposit is not known.  However, the differences in temperature in the similar alteration assemblages  suggest that this could be the case. It also could represent just a smaller system that did not evolve to the same extent as that at Valley and to a lesser extent Bethsaida zone. Chlorite at Bethlehem is part of the phyllic alteration as well as during Na-Ca alteration. The mapped transition from higher Fe chlorite in the core of the porphyry system to the margin where the chlorite is lesser Fe rich and thus more Mg has been noted in modern geothermal systems (Martinez-Serrano and Dubois, 1998; Inoue et al., 2010). These are attributed to changes in fluid chemistry as well as temperature, much like the changes in phengite content in the muscovite. In a constant host rock, higher Fe contents reflect higher temperature of formation (Inoue et al., 2010). The associations of Mg-rich chlorite with illitic micas and Fe-rich chlorite with muscovite at Bethlehem is entirely consistent with what would be expected across the temperature gradient from the core to the distal (>1 km) fringe of the porphyry Cu deposit.     131   5.4. Exploration implications Zonation of major and trace elements in muscovite and chlorite is an integral part of the alteration footprint of porphyry deposits, and can be used to vector towards ore. However, less time consuming techniques than detailed petrography, XRD, and electron microprobe analysis are required in the exploration environment. The SWIR spectroscopy offers this option, but the variations must be calibrated. At Highland Valley, this study has demonstrated a zonation in the Na of the muscovite at the 2200 nm wavelengths and a zonation in the Fe and Mg content in the chlorites at the 2350 nm wavelengths, which can be applied in exploration programs. Thus, these may be used to map the lateral variation of the hydrothermal system or identify superimposing porphyry centers in complex  mineralized areas. Whole rock geochemistry demonstrated that Cs, Rb and Tl may be guide elements to identify the abundance of muscovite in the whole rock. Additionally, higher concentrations of V detected in the whole rock may also be correlated with the higher concentration in the muscovite using laser ablation analysis. Similarly high concentrations of Zn, Co, Mn and Li provide guide elements to chlorite controls on the bulk chemistry of the rock. The concentration of these elements helps to constrain the intensity and lateral zonation of the magmatic hydrothermal system. However more detailed studies on mineral abundances also considering sulfide content will certainly be needed.     132   Figure 5.1: Schematic and comparative diagram showing the variability of muscovite chemistry. Pervasive muscovite (Mp), muscovite replacing biotite (Mb), coarse muscovite (Mc), muscovite in veins (Mv), fine-pervasive muscovite (Mfp), dusty muscovite (Md). Inset aerial photo shows the representative samples chosen for this study (detailed figure is shown in Figure 3.1) and the A-A’ cross section.     133   Figure 5.2: Schematic and comparative diagram showing results of chlorite composition variability. The comparison among the techniques used indicates that the chemistry represents to the types of alteration around the Bethlehem deposits and no host rock influence.     134   References  Abad, I., Gutiérrez-Alonso, G., Nieto, F., Gertner, I., Becker, A., and Cabero, A., 2003, The structure and the phyllosilicates (chemistry, crystallinity and texture) of Talas AlaTau (Tien Shan, Kyrgyz Republic): comparison with more recent subduction complexes, Tectonophysics, v.365, p. 103-127. Ahrens, L.H., 1948, The unique association of thallium and rubidium in minerals: The Journal of Geology, v.56, N6, p.578-590. Ager, C.A., McMillan, W.J. and Ulrych, T.J., 1973, Gravity, magnetics and geology of the Guichon Creek batholith, British Columbia: Ministry of Energy, Mines and Petroleum Resources, Bulletin 62, p.18. ALS Laboratory Group, May 2011, http://www.alsglobal.com Arancibia, O.N., and Clark, A.H., 1996, Early magnetite-amphibole-plagioclase alterationmineralization in the Island Copper porphyry copper-gold-molybdenum deposit, British Columbia: Economic Geology, v.91, p.402-438. Bailey, S.W., 1980, Summary of recommendations of AIPEA nomenclature committee on clay minerals: American Mineralogist, v. 65, p.1-7. Bailey, S.W., 1984, Classification and structures of the micas and crystal chemistry of the true micas, Reviews in Mineralogy, Micas: Mineralogical Society of America, v.13, p. 1-60. Bayliss, P., 1975, Nomenclature of the trioctahedral chlorites: Canadian Mineralogist, v. 13, p.178-180. Brimhall, G.H., Jr., 1977, Early fracture-controlled disseminated mineralization at Butte, Montana: Economic Geology, v.72, p.37-59.     135   Briskey, J.A. and Bellamy, J.R., 1976, Bethlehem Copper’s Jersey, East Jersey, Huestis and Iona Deposits: In Porphyry Deposits of the Canadian Cordillera: The Canadian Institute of Mining and Metallurgy, Special Volume 15, p.105-119. Briskey, J.A., 1981, Geology, petrology, and geochemistry of the Jersey, East Jersey, Huestis, and Iona Porphyry Copper-Molybdenum Deposits, Highland Valley, British Columbia, Ph.D. thesis, Oregon State University, Corvallis, Oregon, p.427. Brown, B.E., and Bailey, S.W., 1962, Chlorite polytypism: I; Regular and semi-random onelayer structures; American Mineralogist, v.47, p.819-50 Casselman, M.J., McMillan, W.J., Newman, K.M., 1995, Highland Valley porphyry copper deposits near Kamloops, British Columbia: A review and update with emphasis on the Valley deposit: Porphyry Deposits of the Northwestern Cordillera of North America: The Canadian Institute of Mining and Metallurgy, Paper 8, p.161-191. Carten, R.B., 1986, Sodium-calcium metasomatism: Chemical, temporal, and spatial relationships at the Yerington, Nevada, porphyry copper deposit: Economic Geology, v.81, p.1495-1519. Cathelineau, M. and Nieva, D., 1985, A chlorite solid solution geothermometer The Los Azufres (Mexico) geothermal system: Contributions to Mineralogy Petrology, v.91, p.235-244. Clark, R.N., 1999, Spectroscopy of rocks and minerals, and principles of spectroscopy, in Rencz, A.N., ed., Remote sensing for the earth sciences: Manual of remote sensing: New York, Wiley, v.3, p.3-58. Chaffee, M.A., 1976, The zonal distribution of selected elements above the Kalamazoo porphyry copper deposit, San Manuel district, Pinal County, Arizona: Journal of Geochemical Exploration, v.5, p. 145-165. Cohen, J.F., 2011, Mineralogy and geochemistry of hydrothermal alteration at the AnnMason porphyry copper deposit, Nevada: Comparison of large-scale ore exploration     136   techniques to mineral chemistry, Master thesis, Oregon State University, Corvallis, Oregon, p.593. Dahl, P.S., When, D.C., and Feldmann, S.G., 1993, The systematics of trace-element partitioning between coexisting muscovite and biotite in metamorphic rocks from the Black Hills, South Dakota, USA: Geochimica et Cosmochimica Acta, v.57, p.2487505. De Caritat, P., Hutcheon, I., and Walshe, J. L., 1993, Chlorite geothermometry: A Review: Clays and Clays Minerals, v.41, No.2, p.219-239. Deer, W.A., Howie, R.A., and Zussman, J., 1992: An introduction to The Rock-Forming Minerals, 2nd edition, p.279-297. Deer, W.A., Howie, R.A., and Zussman, J., 2003: Rock-Forming Minerals, Sheet silicates: Micas, v3A, 2nd edition, p.1-308. Deer, W.A., Howie, R.A., and Zussman, J., 2009: Rock-Forming Minerals, Layered Silicates Excluding Micas and Clay Minerals, v.3B, 2nd edition, p.81-156. Dilles, J.H., 1987, The petrology of the Yerington batholith, Nevada: Evidence for the evolution of porphyry copper ore fluids: Economic Gology, v.82, p.1750-1789. Dilles, J.H., and Einaudi, M.T., 1992, Wall-rock alteration and hydrothermal flow paths about the Ann-Mason porphyry copper deposit, Nevada-A 6-Km Reconstruction: Economic Geology, v.87, p.1963-2001. Dilles, J.H., and Proffett, J.M., 1995, Metallogenesis of the Yerington batholith, Nevada: Arizona Geological Society Digest 20, p.306-315. Dilles, J.H., Proffett J.M., Seedorff, E., Einaudi, M.T., and Barton M.D., 2000, Overview of the Yerington porphyry copper district: Magmatic to non-magmaticc sources of hydrothermal fluids: Their flow paths and alteration affects on rocks and Cu-Mo-FeAu ores, in Thompson, T.B. ed.: Economic Geology, Guidebook 32, p.55-66.     137   Finlow-Bates, T., and Stumpfl, E.F., 1981, The behaviour of so-called immobile elements in hydrothermally altered rocks associated with volcanogenic submarine-exhalative ore depoits: Mineral Deposita, v.16, p.319-328. Foster, M.D., 1962, Interpretation of the composition and a classification of the chlorites: US Geological Survey Professional Paper 414A, p.1-33. Foster, M.D., 1964, Water contents of micas and chlorites: US Geological Survey Professional Paper, 474-F, p.1-15. Frey, M., Teichmuller, M., Teichmüller, R., Mullis, J., Kuenzi, B., Breitschmid, A., Gruner, U., Schwizer, B., 1980, Very low-grade metamorphism in extermnal parts of the Central Alps, illite “crystallinity”, coal rank and fluid inclusion data. Eclogae Geologicae Helvetiae, v.73, p.173-203. Graham, I.J., Cole, J.W., Briggs, R.M. Gamble, J.A., and Smith, I.E.M., 1995, Petrology and petrogenesis of volcanic rocks from Taupo volcanic zone: A general overview: Journal of Volcanology and Geothermal Research, v.68, p. 59-88. Guidotti, C.V., and Sassi, F.P., 1976, Muscovite as a petrogenetic indicator mineral in pelitic schists, Neues Jahrbuch für Mineralogie, v.153, p.97-142. Guidotti, C.V. 1984, Micas in metamorphic rocks: Reviews in Mineralogy, 13, Ed. S. W. Bailey, Mineralogical Society of America, p.357-467. Guidotti, C.V., and Sassi, F.P., 1998, Petrogenetic significance of Na-K white mica mineralogy: Recent advances for metamorphic rocks; European Journal of Mineralogy, v.10, p.815-854. Gutierrez-Alonso, G., and Nieto, F., 1996, White-mica “crystallinity” finite strain and cleavage development across a large Varisca structure, NW Spain: Journal of the Geological Society, v.153, p.287-299. Gustafson, L.B., and Hunt, J.P., 1975, The porphyry copper deposit at El Salvador, Chile: Economic Geology, v.70, N.5, p.857-912.     138   Gonzalez Lopez, J.M., Subias Perez, I., Fernandez-Nieto, C., and Fanlo Gonzalez, I., 1993, Lithium-bearing hydrothermal alteration phyllosilicates related to Portalet fluorite ore (Pyrenees, Huesca, Spain): Clay Minerals, v.28, p.275-83. Hastie, A.R., Kerr, A.C., Pearce, J.A., and Mitchell, S.F., 2007, Classification of altered volcanic island arc rocks using immobile trace elements: development of the Th-Co discrimination diagram: Journal of Petrology, v.48, n°12, p.2341-2357. Helgeson, H.C., Delany, J.M., Nesbitt, H.W., and Bird, D.K., 1978, Summary and critique of thermodynamic properties of rock-forming minerals: American Journal of Science, v.278A. p.229. Hemley, J.J., and Jones, W.R., 1964, Chemical aspects of hydrothermal alteration with emphasis on hydrogen metasomatism: Economic Geology, v.59, p. 538–569. Hemley, J.J., Montoya, J.W., Marinenko, J.W., and Luce, R.W., 1980, Equilibria in the system Al2O3-SiO2-H2O and some general implications for alteration/mineralization processes: Economic Geology, v. 75, p.210–228.  Hey, M.H, 1954, A new review of the chlorite: The Mineralogical Magazine, v.30, p.277292. Herrmann, W., Blake, M., Doyle, M., Huston, D., Kamprad, J., Merry, N. and Pontual, S., 2001, Short wavelength infrared (SWIR) spectral analysis of hydrothermal alteration zones associated with base metal sulfide deposits at Rosebery and Western Tharsis, Tasmania, and Highway-Reward, Queensland: Economic Geology, v. 96, p.939-955. InfoMine, May 2011, http://www.infomine.com Inoue, A., Kurokawa, K., and Hatta, T., 2010, Application of chlorite geothermometer to hydrothermal alteration in toyaha geothermal system, southwestern Hokkaido Japan: Resource Geology, v.60, N°1, p.52-70.     139   Jaboyedoff, M., 1999, Transformation des interstratifiés illite-smectite vers l’illite et la phengite: un exemple dans la série carbonatée du domaine Briansςonnais des Alpes suisses romandes. Thèse Université de Lausanne, p.452. John, D. A., Ayuso, R. A., Barton, M. D., Blakely, R. J., Bodnar, R. J., Dilles, J. H., Gray, F., Graybeal, F. T., Mars J. C., McPhee D. K., Seal, R. R., Taylor, R. D., and. Vikre, P. G, 2010, Porphyry Copper Deposit Model: United States Geological Survey, Scientific Investigations Report, 5070-B, 186 p. Johnson, M., and Oliver, G., 1990, Precollision and postcollision thermal events in the Himalaya: Geology v.18, p.753-756. Jones, M.B., 1975, Hydrothermal alteration and mineralization of the Valley Copper Deposit, Highland Valley, British Columbia, unpublished PhD thesis, Oregon State University, Corvallis, Oregon. Jones, S., Herrmann, W., and Gemmell, J.B., 2005, Short wavelength infrared spectral characteristics of the HW horizon: Implications for exploration in the Myra Falls volcanic-hosted massive sulfide camp Vancouver Island, British Columbia, Canada: Economic Geology, v.100, p. 273-294. Kent, A.J.R., Stolper, E.M., Francis, D. Woodhead, J., Frei, R., Eiler, J., 2004, Mantle heterogeneity during the formation of the North Atlantic Igneous Province: Constraints from trace element and Sr-Nd-Os-O isotope systematics of Baffin Island picrites: Geochemistry Geophysics Geosystems, v.5, number 11, p.1-26. Kerr, P.F. 1959, Silicates: Sheet structures and Mineraloids: Optical Mineralogy, third edition, chapter 16, p.383-424. Klein, C., and Hurlbut, Jr.,C.S., 1985, Manual of Mineralogy (after James D. Dana), 20th edition, p. 367-583. Kranidiotis, P., and MacLean, W.H., 1987, Systematics of chlorite alteration at the Phelps Dodge massive sulfide deposit, Matagami, Quebec: Economic Geology, v.82, p.18981911.     140   Lanzon B., and Champion, D., 1991, The I-S to illite reaction in the late stages of diagenesis: American Journal of Science, v.291, p. 473-506. Lentz, D.R., Hall, D.C., and Hoy, L.D., 1997, Chemostratigraphic, alteration and oxygen isototpic trends in a profile through the stratigraphic sequence hosting the Heath Steele B zone massive sulphide deposit, New Brunswick: The Canadian Mineralogist, 35, p.841-74. Lowell, J.D. and Guilbert, J.M., 1970, Lateral and vertical alteration-mineralization zoning in porphyry ore deposits: Economic Geology, v.65, p. 373-408. Martinez-Serrano, R.G., and Dubois, M., 1998, Chemical variations in chlorite at the Los Humeros geothermal system, Mexico: Clays and clay Minerals, v.46, p.615-628. McMillan, W.J. 1976, Geology and genesis of the Highland Valley ore deposits and the Guichon Creek batholith: In Porphyry Deposits of the Canadian Cordillera: The Canadian Institute of Mining and Metallurgy, Special Volume 15, p.85-104. McMillan, W.J., 1985, Geology and ore deposits of the Highland Valley camp: Geological Association of Canada, Mineral Deposits Division, Field guide and reference manual series, Number 1, p.1-87. Meyer, C. and Hemley, J.J., 1967, Wall Rock Alteration in Barnes, H.L., ed., Geochemistry of hydrothermal ore deposits: New York, Holt, Rinehart and Winston, p.166-235. Meunier, A. and Velde, B., 2004, Illite, origins, evolution and metamorphism: Springer, New York, p.286. Ministry of Energy and Mines, May 2011, http://www.empr.gov.bc.ca/Mining/Geoscience Monger, J.W.H., and Price, R.A., 1979, Geodynamic Evolution of the Canadian Cordillera – progress and problems: Canadian Journal of Earth Sciences, v.16, p.770-791. Montoya, J.W., and Hemley, J.J., 1975, Activity relations and stabilities in alkali feldspar and mica alteration reactions: Economic Geology, v.70, p.577-583.     141   Mortimer, N., 1986, Two belts of Late Triassic, arc-related, potassic igneous rocks in the North American Cordillera: Geology, 14, p. 1035-1038. Mortimer, N., Van Der Heyden, P., Armstrong, R.L., and Harakal, J., 1990, U-Pb and K-Ar dates related to the timing of magmatism and deformation in the Cache Creek Terrane and Quesnellia, southern British Columbia: Canadian Journal of Earth Sciences v.27, p.117-123. Munoz, 1984, F-OH and Cl-OH Exchange in micas with applications to hydrothermal ore deposits in micas, edited by Bailey, S.W., Reviews in Mineralogy: Mineralogical Society of America, v.13, p.469-491. Northcote, K.E., 1969, Geology and geochronology of the Guichon Creek Batholith, British Columbia Department of Mines and Petroleum Resources Bulletin, N°56, p.73 Osatenko, M.J. and Jones, M.B., 1976, Valley Copper. In Porphyry Deposits of the Canadian Cordillera: The Canadian Institute of Mining and Metallurgy, Special Volume 15, p.130-143. Parry, W.T., Ballantyne, J.M., and Jacobs, D.C., 1984, Geochemistry of hydrothermal sericite from Roosvelt Hot Springs and the Tintic and Santa Rita porphyry copper systems: Economic Geology, v.79, p.72-86. Pontual, S., Merry, N., and Gamson, P., 1997, Spectral interpretation field manual: Kew, Victoria 3101, Australia, Ausspec International Pty. Ltd., G-Mex, v.1, p.169. Post, J.L., and Noble, P.L., 1993, The near-infrared combination band frequencies of dioctohedral smectites, micas and illites: Clays and Clay Minerals, v.41, p.639-644. Pouchou, J.L. and Pichoir, F. (1985): PAP φ(ρZ) procedure for improved quantitative microanalysis. Microbeam Analysis, p.104-106. Rabbia, O.M., Hernández, L.B., French D.H., King, R.W., Ayers J.C., 2009, The El Teniente porphyry Cu-Mo deposit from a hydrothermal rutile perspective: Mineralium Deposita v.44, p.849-866.     142   Reed, A.J. and Jambor, J.L., 1976, Highmont: Linearly zoned copper-molybdenum porphyry deposits and their significance in the genesis of the Highland Valley Ores, In Porphyry Deposits of the Canadian Cordillera: The Canadian Institute of Mining and Metallurgy, Special Volume 15, p.163-181. Rieder, M., Cavazzini, G, D’Yakonov, Y.S., Frank-Kamenetskii, V.A., Gottardi G., Guggenheim, S., Koval, P.V., Müller, G., Neiva, A.M.R., Radoslovich, E.W., Robert J.L., Sassi, F.P., Takeda, H., Weiss, Z., and Wones, D.R., 1998, Nomenclature of the micas: The Canadian Mineralogist, v.36, p.905-912. Rieder, M, 2001, Mineral nomenclature in the mica group: the promise and the reality: European Journal of Mineralogy 13, p.1009-1012. Rusk, B.G., Reed, M.H., and Dilles, J.H., 2008, Fluid inclusion evidence for magmatichydrothermal fluid evolution in the porphyry copper-molybdenum deposit at Butte, Montana: Economic Geology, v.103, p.307-334. Roy, B., and Clowes, R., 2000, Seismic and potential-field imaging of the Guichon Creek batholith, British Columbia, Canada, to delineate structures hosting porphyry copper deposits: Geophysics, v.65, N5, p.1418-1434. San Marco Resources, May 2011, http://www.sanmarcocorp.com/s/Alwin.asp. Seedorff, E., Dilles, J.H., Proffett, Jr. J.M., Einaudi, M.T., Zurcher, L., Stavast, W.J.A., Johnson, D.A. and Barton, M.D., 2005, Porphyry deposits: characteristics and origin of hypogene features: Economic Geologists 100th Anniversary Volume, p.251-298. Shikazono, N. and Kawahata, H., 1987, Compositional differences in chlorite from hydrothermally altered rocks and hydrothermal ore deposits: Canadian Mineralogist, v.25, p.465-474. Sillitoe, R.H., 1993, Epithermal models: Genetic types, geometrical controls and shallow features: Geological Association of Canada Special Paper 40, p.403-417. Sillitoe, R.H., 2000, Gold-rich porphyry deposits: Descriptive and genetic models and their role in exploration and discovery: Reviews in Economic Geology, v.13, p.315-345.    143   Sillitoe, R.H., 2010, Porphyry Copper Systems: Economic Geology, v.105, p.3-41. Smeds, S.A., 1992, Trace elements in potassium-feldspar and muscovite as a guide in the prospecting for lithium- and tin-bearing pegmatite’s in Sweden: Journal of Geochemical Exploration, v.42, Issues 2-3, p.351-369. Smith, W.C., Bannister, F. A., and Hey, M.H., 1946, Pennantite, a new manganese-rich chlorite from Benallt mine, Rhiw, Caernarvonshire, Mineralogical Magazine, v. 27, p.217-30. Takeshita, H., Gouzu, C., and Itaya, T., 2004, Chemical features of white micas from the Piemonte calc-schists, Western Alps and implications for K-Ar ages of metamorphism: Godwana Research, v.7, p.457-466. Teck, May 2011, www.teck.com Tiller, K.G. and Hodgson, J.F., 1962, The specific sorption of cobalt and zinc by layer silicates, 9th Conf.: Clays and Clay Minerals, p. 393–403. Tosdal, R.M, Dilles, J.H., and Cooke, D.R., 2009, From source to sinks in auriferous magmatic-hydrothermal porphyry and epithermal deposits: Elements, v.5, p.289-295. Thompson, A.J.B., Hauff, P.L., and Robitaille, A.J., 1999, Alteration mapping in exploration: Application of short-wave infrared (SWIR) spectroscopy: Economic Geology, v.39, p.16-26. Waldner, M.W., Smith, G.D. and Willis, R.O., 1976, Lornex. In Porphyry Deposits of the Canadian Cordillera. Edited by A. Sutherland Brown: The Canadian Institute of Mining and Metallurgy, Special Volume 15, p.120-129. Walshe J.L., 1986, A Six-component chlorite solid solution model and the conditions of chlorite formation in hydrothermal and geothermal systems: Economic Geology, v.81, p.681-703.     144   Wiewióra, A., and Weiss, Z., 1990, Crystallochemical classification of phyllosilicates based on the unified system of projection of chemical composition: II. The chlorite Group: Clay Minerals, v.25, p.83-92. Witt, P., 2008, Review of Highland Valley Copper Operations, British Columbia: Technical Report, Highland Valley Copper. Zane, A., Sassi, R., and Guidotti, C.V., 1998, New data on metamorphic chlorite as a petrogenetic indicador mineral with special regard to greenschist-facies Rocks: Canadian Mineralogist., v.36, p.26.     145   APPENDIX A1 XRD analysis in comparison with SWIR data for muscovites  A1.1. Introduction Wavelength position typically overlaps for minerals such as muscovite, alunite, illitesmectite and illite in the AlOH feature at around 2200 nm (Thompson et al., 1999). For this reason, the distinction between muscovite and illite is challenging or leads to ambiguous identification. In this appendix, a few representative examples comparing short-wave infrared (SWIR) data X-ray powder-diffraction (XRD) analysis are presented. However these analyses were mostly done on all fine-to medium-grained muscovite studied in detail in this thesis. A1.2. Methodology X-ray powder-diffraction (XRD) was done on 15 samples from the transect AlwinValley-Bethlehem. Sample material was mainly extracted from the off-cuts of thin sections using a Dremel Micro Drill tool in the specific areas of interest. XRD was necessary for proper mineral identification. Glycol treatment was later done to detect the smectite content in mica. On the other hand, SWIR was used on the whole set of samples collected for the project (204 samples). But only the samples selected for detailed chemical work for this study were analyzed in detail. SWIR spectra are presented using the HullQuot (when the spectrum is normalized between zero to one) in the Y-axes for ease of comparison and to see the full range of the spectra. Wavelength in nm is presented the X-axes. A1.3.Results After comparing the general spectra of the samples, a correct identification of illite versus muscovite was usually possible by comparing the depth of absorption feature (hqd) at 1900 nm and 2200 nm. Figure A1 shows an example how illite can clearly be distinguished from muscovite by comparing the ratios of the maximum depth of the absorption features hqd1900 and hqd2200 (hqd1900/hqd2200). The ratio is greater than 0.75 for illite and ilite/smectite, whereas the ratio ranges from 0.21 to 0.69 for muscovite. Kaolinite has a ratio    146   of 0.79. Note that the ratio of BTA20 is extremely high. This value may be to the particularly short depth of absorption feature at 2200 nm, which may reflect the low muscovite/illite abundance.  A1.4. Examples Two of the samples analyzed by XRD were from coarse muscovite and provide a baseline of a well-crystalline muscovite to which the other samples can be compared (Figure A2). The full-width at half-height (FWHM) values obtained are 0.132° 2θ for the Valley deposit sample (sample HVD049) and 0.112 for the Valley margin (sample HVA01). The latter is presented in Figure A2. Theoretically, the FWHM is lower than 0.25 °2θ for mica and higher for illite (Lanzon and Champion 1991; Jaboyedoff, 1999; Meunier and Velde, 2004). The sample HVA01 represents a quartz-sulfide vein with a selvage of muscovite in the phyllic alteration of the Valley margin. (Figure A2 - gray area). SWIR shows a typical spectrum for muscovite. The deeper absorption feature (hqd) at around 1900 nm is shorter than the one around the 2200 nm, resulting in the hqd1900/hqd2200 ratio of 0.33. In contrast, in the same sample (Figure A3, cream-colored area), XRD reflect kaolinite and a small peak of muscovite or illite (this is difficult to determinate because the small content of these phases); the hqd1900/hqd2200 for the kaolinite is 0.79. After glycol treatment, smectite was confirmed for this part of the sample. SWIR also detect the kaolinite spectra. Sample HVD06 is green fine-to medium-grained muscovite from the Valley margin. XRD of this sample demonstrates the muscovite content FWHM (0.16°2θ) and absence of illite or smectite. This is consistent with the data obtained using electron microprobe analysis. SWIR spectrum shows a deeper absorption feature (hqd) at around 2200 nm than at around 1900 nm, resulting in the hqd1900/hqd2200 ratio of 0.69 (Figure A4) Sample BTA04 from the sodic-calcic area of Bethlehem shows that the FWHM was 1.232°2θ much higher than pure illite and probably corresponds to an illite+smectite mixed layer clay (Figure A5,A6). In the SWIR spectrum, the deeper absorption feature (hqd) at around 1900nm is shorter than that around the 2200nm wavelength. The hqd1900/hqd2200 is 1.23.    147   Sample G107, from the phyllic to weak to moderate sodic-calcic alteration, shows a mixture of muscovite and illite. According to microprobe results, the K+ content in G107 is high enough to be considered muscovite. However, petrographic observations and XRD analysis reveal the presence of illite indicating a mixture of both micas in this sample (Figure A7, A8) and a small amount of smectite was also identified by XRD. SWIR data shows a deeper absorption feature at around 2200nm than that around 1900 nm. The hqd1900/hqd2200 is 0.54  Figure A1.1: Comparative graph showing the relation of the ratio of depth at the minimum point of absorption feature between 1900 nm and 220 0nm measured using SWIR data and the mineral classification by XRD. Hull quotient depth (hqd) represents the spectral feature depth at 1900 and 2200 nm. Green dots correspond to illite, and illite+smectite samples, the darkest green is a kaolinite-rich sample and the red dots are muscovite, muscovite+smectite, muscovite+kaolinite samples. Samples with XRD analyses: BTA02, BTA04, BTA14, G107, G131, G134, G175, G184, HVA01, HVA01kao, HVD050, HVD044 (outer side the coarse muscovite halo), HVD049, HVD036 and HVD06. The rest of the samples are interpreted by electron microprobe.     148   Figure A1.2: Sample HVA01 (gray area) from the Valley margin (phyllic alteration). A. Hand sample showing the area of thin section. Circles correspond to microprobe analysis, whereas red crosses represent area of XRD analysis. B. Cross-polarized photomicrograph shows coarse muscovite (Mc). C. SWIR spectrum showing the absorption feature depth (hqd) at around 1900 nm and 2200 nm for the muscovite. E. XRD spectra after glycol treatment showing muscovite for which the full-width at half-height (FWHM) is 0.112 °2θ. It also shows a minor peak of kaolinite. Smectite was not detected.     149   Figure A1.3: Sample HVA01 (creamy area) from the Valley margin (phyllic alteration). A. Hand sample showing the area of thin section. Circles correspond to microprobe analysis, whereas red crosses represent area of XRD analysis. B. Cross-polarized photomicrograph shows kaolinite/illite-smectite with individual grains of muscovite (Mp). C. SWIR spectrum showing the absorption feature depth (hqd) at around 1900 nm and 2200 nm for the muscovite. E. XRD spectra after glycol treatment shows principally kaolinite and small amount of interlayer illite-smectite mixed mineral.     150   Figure A1.4: Sample HVD06 (margin of the Valley deposit). A. Hand sample shows green-fine to mediumgrained muscovite and the area of the thin section. Circles correspond to microprobe analysis whereas red crosses represent area of XRD analysis. B. Cross-polarized photomicrograph shows pervasive muscovite (Mp) and muscovite after biotite (Mb) intergrown with quartz and overprinted by calcite. C. SWIR spectrum of the same sample shows a deeper feature at around 1900 nm and 2200 nm. D. XRD analysis show a narrow peak at 10°2θ that correspond to a muscovite crystal. The full-width at half-height (FWHM) is 0.16 °2θ. No smectite was detected in this sample.     151   Figure A1.5: BTA04 sample from the sodic-calcic area of Bethlehem phase. A. Hand sample shows the area of thin section, circles correspond to microprobe analysis, red crosses represent area of XRD analysis. B. Crosspolarized photomicrograph of the XRD area (point 1 in Figure A) shows illite+smectite dusting albite (albitequartz-epidote assemblage). C. Cross-polarized photomicrograph of the areas selected for microprobe analysis (point 2 in Figure A) shows dusty muscovite (Md) and chlorite crystals (chl) (note the size of the dusty muscovite and the high birefringence color in comparison to the illite. D. SWIR spectrum showing the absorption feature depth (hqd) at around 1900 nm and 2200 nm.     152   Figure A1.6. XRD spectra of sample BTA04 showing interlayered illite+smectite mineral with full-width at half-height (FWHM) is 1.232°2θ. XRD spectra after glycol treatment shows shift the mixed mineral away from the original spectra to his 10°2θ. The spectrum also exhibits chlorite and albite peaks.     153   Figure A1.7: Sample G107 of the phyllic/sodic-calcic transition alteration of the Bethlehem phase. A. Hand sample showing the area of thin section. Circles correspond to microprobe analysis, whereas red crosses represent area of XRD analysis. B. Cross-polarized photomicrograph shows fine pervasive muscovite completely replacing feldspar (plagioclase). C. Parallel-polarized photomicrograph of photo in B, showing illite and chlorite. D. SWIR Spectrum of the off-cut of the thin section interpreted to reflect illite and epidote. SWIR spectrum shows the absorption features at around 1900 nm and 2200 nm (ratio 0.54).     154   Figure A1.8: XRD spectrum of sample G107 showing muscovite as well as albite and calcite The width of the peak at 10 2°θ peak suggests the presence of minor interlayer illite-muscovite. F. XRD spectrum after glycol treatment shows a slight shift in the 10 °2θ peak indicative of illite-smectite interlayer. The full-width at halfheight (FWHM) is 0.166 °2θ.     155   APPENDIX A2 A2. Petrographic hand sample description This appendix describes the hand samples collected during two field campaigns. Table A2.1 corresponds to the petrographic description of the selected samples in the transect (Alwin-Valley-Bethlehem). Table A2.2 corresponds to the entire data set consisting of samples collected by Tatiana Alva, Richard Tosdal and John Dilles. This appendix corresponds to the data discussed in chapter 3.     156      Table A2.1: Hand sample petrographic description of selected samples. Transect (Alwin-Valley-Bethlehem).                                  Elevation is given in meter above sea level. Muscovite (Ms), Quartz (Qz), Bornite (Bn), Sericite (Ser), Chalcopyrite (Cp), Pyrite (Py), Epidote (Ep), Chlorite (Chl), Iron oxide (OxFe), Pyrite (Py), Specular hematite (SpHm), Amphibole (Amph), K-feldspar (Ksp), Albite (alb), Goethite (goeth), Carbonate (carb), Hornblenden(Hnbd), Biotite (bt), Beth-crowd (Bethsaida crowed), Beth-equig (Bethsaida equigranular), Copper oxide (Cu-ox).       157        Table A2.2: Hand sample petrographic description – all data set.                                       158   Table A2.2: Hand sample petrographic description – all data set.       159      Table A2.2: Hand sample petrographic description – all data set.                                         160      Table A2.2: Hand sample petrographic description – all data set.                  161   APPENDIX A3 A3. Electron microprobe analyses of muscovite and chlorite This appendix consists of electron microprobe analyses of muscovite and chlorite from the Bethsaida phase, Bethlehem phase and Guichon Variety of the Highland Valley district discussed in Chapter 4. It is divided into four parts: A3.1 Electron microprobe analyses of muscovite from the Bethsaida phase A3.2. Electron microprobe analyses of muscovite from the Bethlehem phase and Guichon Variety. A3.3. Electron microprobe analyses of chlorite from the Valley deposit A3.4. Electron microprobe analyses of chlorite from the Bethlehem phase and Guichon Variety. Analyses with totals above 98 wt% (total oxide +H2O) were considered. Values of muscovites are given in oxides % and cations per formula unit on the basis of O10(OH)2 and Fe as FeO. Values of chlorites are given in oxides % and cations per formula unit on the basis of O10(OH)8 and Fe as FeO. Full details of the parameters for formula standardization are given in Table 4.2, Chapter 4.       162      Table A3.1: Electron microprobe analyses of muscovite – Bethsaida phase.   *Normalized on the basis of 11 anhydrous oxygens for muscovite           163      Table A3.1: Electron microprobe analyses of muscovite – Bethsaida phase   *Normalized on the basis  *Normalized on the basis of 11 anhydrous oxygen for muscovite     164        Table A3.1: Electron microprobe analyses of muscovite – Bethsaida phase   *Normalized on the basis of 11 anhydrous oxygen for muscovite         165        Table A3.1: Electron microprobe analyses of muscovite – Bethsaida phase   *Normalized on the basis of 11 anhydrous oxygen for muscovite        166        Table A3.1: Electron microprobe analyses of muscovite – Bethsaida phase   *Normalized on the basis of 11 anhydrous oxygen for muscovite        167        Table A3.1: Electron microprobe analyses of muscovite – Bethsaida phase   *Normalized on the basis of 11 anhydrous oxygen for muscovite        168        Table A3.1: Electron microprobe analyses of muscovite – Bethsaida phase   *Normalized on the basis of 11 anhydrous oxygen for muscovite        169        Table A3.1: Electron microprobe analyses of muscovite – Bethsaida phase   *Normalized on the basis of 11 anhydrous oxygen for muscovite        170        Table A3.1: Electron microprobe analyses of muscovite – Bethsaida phase   *Normalized on the basis of 11 anhydrous oxygen for muscovite        171        Table A3.1: Electron microprobe analyses of muscovite – Bethsaida phase   *Normalized on the basis of 11 anhydrous oxygen for muscovite        172        Table A3.1: Electron microprobe analyses of muscovite – Bethsaida phase   *Normalized on the basis of 11 anhydrous oxygen for muscovite        173        Table A3.1: Electron microprobe analyses of muscovite – Bethsaida phase   *Normalized on the basis of 11 anhydrous oxygen for muscovite        174        Table A3.1: Electron microprobe analyses of muscovite – Bethsaida phase   *Normalized on the basis of 11 anhydrous oxygen for muscovite        175        Table A3.1: Electron microprobe analyses of muscovite – Bethsaida phase   *Normalized on the basis of 11 anhydrous oxygen for muscovite        176        Table A3.1: Electron microprobe analyses of muscovite – Bethsaida phase   *Normalized on the basis of 11 anhydrous oxygen for muscovite        177        Table A3.1: Electron microprobe analyses of muscovite – Bethsaida phase   *Normalized on the basis of 11 anhydrous oxygen for muscovite        178        Table A3.1: Electron microprobe analyses of muscovite – Bethsaida phase                                   *Normalized on the basis of 11 anhydrous oxygens for muscovite    179      Table A3.2: Electron microprobe analyses of muscovite – Bethlehem phase and Guichon Variety.  *Normalized on the basis of 11 anhydrous oxygen for muscovite        180        Table A3.2: Electron microprobe analyses of muscovite – Bethlehem phase and Guichon Variety   *Normalized on the basis of 11 anhydrous oxygen for muscovite        181        Table A3.2: Electron microprobe analyses of muscovite – Bethlehem phase and Guichon Variety   *Normalized on the basis of 11 anhydrous oxygen        182        Table A3.2: Electron microprobe analyses of muscovite – Bethlehem phase and Guichon Variety   *Normalized on the basis of 11 anhydrous oxygen for muscovite        183        Table A3.2: Electron microprobe analyses of muscovite – Bethlehem phase and Guichon Variety   *Normalized on the basis of 11 anhydrous oxygens for muscovite       184        Table A3.2: Electron microprobe analyses of muscovite – Bethlehem phase and Guichon Variety   *Normalized on the basis of 11 anhydrous oxygens for muscovite         185        Table A3.2: Electron microprobe analyses of muscovite – Bethlehem phase and Guichon Variety   *Normalized on the basis of 11 anhydrous oxygens for muscovite         186      Table A3.2: Electron microprobe analyses of muscovite – Bethlehem phase and Guichon Variety   *Normalized on the basis of 11 anhydrous oxygens for muscovite     187        Table A3.2: Electron microprobe analyses of muscovite – Bethlehem phase and Guichon Variety   *Normalized on the basis of 11 anhydrous oxygens for muscovite         188        Table A3.2: Electron microprobe analyses of muscovite – Bethlehem phase and Guichon Variety   *Normalized on the basis of 11 anhydrous oxygens for muscovite        189   Table A3.3: Electron microprobe analyses of chlorite – Valley deposit  *Normalized on the basis of 14 anhydrous oxygens for chlorite      190   Table A3.3: Electron microprobe analyses of chlorite – Valley deposit.  *Nomalized on the basis of 14 anhydrous oxygens for chlorite      191      Table A3.3: Electron microprobe analyses of chlorite – Valley deposit                                     *Normalized on the basis of 14 anhydrous oxygens for chlorite     192      Table A3.4: Electron microprobe analyses of chlorite – Bethlehem phase and Guichon Variety.     *Normalized on the basis of 14 anhydrous oxygens for chlorite     193      Table A3.4: Electron microprobe analyses of chlorite – Bethlehem phase and Guichon Variety      *Normalized on the basis of 14 anhydrous oxygens for chlorite     194      Table A3.4: Electron microprobe analyses of chlorite – Bethlehem phase and Guichon Variety      *Normalized on the basis of 14 anhydrous oxygens for chlorite     195      Table A3.4: Electron microprobe analyses of chlorite – Bethlehem phase and Guichon Variety      *Normalized on the basis of 14 anhydrous oxygens for chlorite     196      Table A3.4: Electron microprobe analyses of chlorite – Bethlehem phase and Guichon Variety      *Normalized on the basis of 14 anhydrous oxygens for chlorite     197      Table A3.4: Electron microprobe analyses of chlorite – Bethlehem phase and Guichon Variety      *Normalized on the basis of 14 anhydrous oxygens for chlorite     198      Table A3.4: Electron microprobe analyses of chlorite – Bethlehem phase and Guichon Variety      *Normalized on the basis of 14 anhydrous oxygens for chlorite     199      Table A3.4: Electron microprobe analyses of chlorite – Bethlehem phase and Guichon Variety      *Normalized on the basis of 14 anhydrous oxygens for chlorite     200      Table A3.4: Electron microprobe analyses of chlorite – Bethlehem phase and Guichon Variety      *Normalized on the basis of 14 anhydrous oxygens for chlorite     201      Table A3.4: Electron microprobe analyses of chlorite – Bethlehem phase and Guichon Variety           202      Table A3.4: Electron microprobe analyses of chlorite – Bethlehem phase and Guichon Variety      *Normalized on the basis of 14 anhydrous oxygens for chlorite     203   Table A3.4: Electron microprobe analyses of chlorite – Bethlehem phase and Guichon Variety                                   *Normalized on the basis of 14 anhidrous oxygens for chlorite       204   A4. LA-ICP-MS analyses of muscovite and chlorite This appendix consists of LA-ICP-MS analyses of muscovite and chlorite from the Bethsaida phase, Bethlehem phase and Guichon Variety of the Highland Valley district. It is divided into four parts: A4.1. LA-ICP-MS limit of detection for standard GSE-1G, A4.2. LA-ICP-MS analyses of muscovite (grain-mount method), A4.3. LA-ICP-MS analyses of chlorite (grain-mount method), A4.4. LA-ICP-MS analyses of muscovite (thin-section method), and A4.5. LA-ICP-MS analyses of chlorite (thin-section method). Concentration value of each element is given in ppm. The database was normalized to SiO2 wt% defined by electron microprobe measurement presented in appendix A3. An internal error (σ=±1 wt%) for SiO2 values was incorporated in the normalization.     205   Table A4.1. Error percentages based on average and standard deviation of analytical runs for limits of detection for GSE-1G standard.  *See laser ablation methodology (Chapter 4) for plug description.        206      Table A4.2: LA-ICP-MS analyses of muscovite (grain-mount method).         207      Table A4.2: LA-ICP-MS analyses of muscovite (grain-mount method).          208      Table A4.2: LA-ICP-MS analyses of muscovite (grain-mount method).           209   Table A4.2: LA-ICP-MS analyses of muscovite (grain-mount method).          210      Table A4.2: LA-ICP-MS analyses of muscovite (grain-mount method).          211      Table A4.2: LA-ICP-MS analyses of muscovite (grain-mount method).          212      Table A4.2: LA-ICP-MS analyses of muscovite (grain-mount method).          213      Table A4.2: LA-ICP-MS analyses of muscovite (grain-mount method).          214      Table A4.2: LA-ICP-MS analyses of muscovite (grain-mount method).          215      Table A4.2: LA-ICP-MS analyses of muscovite (grain-mount method).          216      Table A4.2: LA-ICP-MS analyses of muscovite (grain-mount method)             217   Table A4.2: LA-ICP-MS analyses of muscovite (grain-mount method).                                         218        Table A4.3: LA-ICP-MS analyses of chlorite (grain-mount method)         219        Table A4.3: LA-ICP-MS analyses of chlorite (grain-mount method).         220        Table A4.3: LA-ICP-MS analyses of chlorite (grain-mount method).          221        Table A4.3: LA-ICP-MS analyses of chlorite (grain-mount method).          222        Table A4.3: LA-ICP-MS analyses of chlorite (grain-mount method).                                       223        Table A4.4: LA-ICP-MS analyses of muscovite (thin-section method).          224      Table A4.4: LA-ICP-MS analyses of muscovite (thin-section method).                                     225        Table A4.5: LA-ICP-MS analyses of chlorite (thin-section method).                                        226   APPENDIX A5 A5.Whole rock geochemistry of selected samples of Highland Valley district This appendix consists of whole rock geochemistry of selected samples from the transect Alwin-Valley-Bethlehem discussed in chapter 4. Element concentration is given in ppm and wt%.    Table A5.1 Upper and lower detection limits (LOD) for geochemistry (ALS Chemex method ME-MS61)                                   227      Table A5.2: Whole rock geochemistry from the transect Alwin-Valley-Bethlehem.                  228      Table A5.2: Whole rock geochemistry from the transect Alwin-Valley-Bethlehem.                  229      Table A5.2: Whole rock geochemistry from the transect Alwin-Valley-Bethlehem.                  230   Table A5.2: Whole rock geochemistry from the transect Alwin-Valley-Bethlehem.                                       231   APPENDIX A6 A6. SWIR data of selected samples of Highland Valley district This appendix consists of short-wave infrared methodology (SWIR) data of selected samples from the transect Alwin-Valley-Bethlehem discussed in Chapter 4 and Appendix A, using a portable reflectance spectrometer ASD Terraspec ®. Analytical spectra interpretation used The Spectral Geologist software (TSA_S). Wavelength 2200nm (w2200) is the absorption feature for muscovite and wavelength 2350nm (w2350) is the absorption feature for chlorite. Maximum depth of the absorption features in the wavelength 1900nm and 2200nm are (hqd1900) and (hqd2200), respectively.           232      Table A6.1: SWIR data from selected samples of the transect Alwin-Valley-Bethlehem.           233   

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.24.1-0053171/manifest

Comment

Related Items