Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Bedrock geochemistry of porphry copper deposits, Highland Valley, British Columbia Olade, Moses Ayodele Deleson 1974

You don't seem to have a PDF reader installed, try download the pdf

Item Metadata

Download

Media
UBC_1975_A1 O43_3.pdf [ 30.72MB ]
[if-you-see-this-DO-NOT-CLICK]
Metadata
JSON: 1.0052878.json
JSON-LD: 1.0052878+ld.json
RDF/XML (Pretty): 1.0052878.xml
RDF/JSON: 1.0052878+rdf.json
Turtle: 1.0052878+rdf-turtle.txt
N-Triples: 1.0052878+rdf-ntriples.txt
Original Record: 1.0052878 +original-record.json
Full Text
1.0052878.txt
Citation
1.0052878.ris

Full Text

BEDROCK GEOCHEMISTRY OF PORPHYRY COPPER DEPOSITS, HIGHLAND VALLEY, BRITISH COLUMBIA  "  M06ES AYODELE DELESON OLADE Sc., (Hons.), University of Ibadan, Nigeria, 1969 M. Sc., University of Alberta, 1972  A THESIS SUBMITTED IN PARTIAL FULFILLMENT DF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in the department of GEOLOGICAL SCIENCES  We accept this thesis as conforming to the required starncjard  The University of British Columbia October 197^  In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree the Library shal make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of m y Department by his representatives. It is understood that copying or publication of this thesis for financial gain shal not be alowed without m y written permission.  Department of The University of British Cou lmba i Vancouver 8. Canada CJ£VLJOC-,ICA-L.  Date 7^ N|ov/. 19 7 f  SaBr^CES  ia  ABSTRACT  The f e a s i b i l i t y of u t i l i z i n g bedrock and mineral geochemistry i n the exploration for porphyry copper deposits has been investigated i n the Highland Valley copper d i s t r i c t .  More than  1500 bedrock samples collected from the v i c i n i t y of the Valley Copper, Bethlehem-JA, Lornex, Highmont and Skeena deposits together with 60 fresh unmineralized samples covering the Guichon Creek batho l i t h (Northcote, 1968) were analyzed for more than 20 elements using t o t a l and p a r t i a l digestion.  An efficacious sulphide-selective  technique, not used previously i n bedrock geochemistry was developed during this investigation. Chemical variations i n fresh rocks of the Guichon Creek batholith are consistent with a model of fractional c r y s t a l l i z a t i o n of a calc-alkaline d i o r i t i c magma, Cu, l i k e other femic elements (Zn, Mn, V, T i , Ni, Co, Fe, Mg), generally decreases with increasing magmatic fractionation.  This geochemical pattern i s commonly char-  a c t e r i s t i c of unmineralized intrusions suggesting that ore metals were not derived by differentiation of a Cu-rich Guichon Creek magma as proposed by previous workers,  Results of isotopic studies (Field  et a l . , 1973) are however, consistent with a model of derivation of ore metals from a subcrustal source, most probably subducted oceanic crust or upper mantle. Detailed bedrock geochemistry around mineralization reveals that S and Cu show the highest geochemical contrast, with halos extending up to 0.5km from mineralized zones.  Of these two elements,  ib  S shows the more consistent pattern. phile elements (Rb, Sr  f  Dispersions of the l i t h o -  Ba, K, Ca, Na) are controlled "by type  and intensity of wall-rock alteration, with halos extending s l i g h t l y beyond ore zones but within the alteration envelope. Distribution of the femic elements (Zn, Mn, V, T i , Ni, Co, Fe,  Mg)  i s controlled principally by primary lithology, although minor hydrothermal redistribution i s apparent.  Hg defines a broad  anomaly at Bethlehem-JA but i s absent at Valley Copper. B anomalies are well developed at Lornex and Highmont but less prominent at Valley Copper and Bethlehem-JA. Results of factor analysis are consistent with subjective interpretations of metal associations and ore-forming processes, Mineral geochemistry indicates that b i o t i t e , magnetite and quartz-feldspar phases from mineralized samples are enriched i n Cu but depleted i n Ni, Zn, Mn, Co and Mg, relative to background samples.  Better geochemical contrast i s obtained with whole-rock  than mineral analysis, consequently the use of mineral phases offers no advantages for exploration i n the Highland Valley, In exploration for porphyry copper deposits of the Highland Valley type, S, Cu, Rb, Sr, Ba, K, Na, B and Hg i n bedrock can be useful i n delineating intensely altered and mineralized zones.  ii TABLE OF CONTENTS Page ABSTRACT  i  TABLE OF CONTENTS  i i  LIST OF TABLES  ix  LIST OF FIGURES (Volume l )  xiii  LIST OF FIGURES (Volume 11)  •  xviii  LIST OF PLATES  xxiii VYV1  ACKNOWLEDGEMENTS 1  CHAPTER ONE: INTRODUCTION  2 2  GENERAL STATEMENT LOCATION AND ACCESS  .1..'  3  OBJECTIVES OF STUDY  3  BEDROCK GEOCHEMISTRY IN MINERAL EXPLORATION - PREVIOUS WORK  5  (a) Regional Geochemical Patterns Cb) Hydrothermal Dispersion Patterns (c) Mineral Geochemical Patterns  CHAPTER TWO: GEOLOGIC SETTING OF GUICHON CREEK BATHOLITH I:  GUICHON CREEK BATHOLITH  5 7 9  12 12 13  REGIONAL SETTING  13  PETROLOGY AND STRUCTURE  1^  ECONOMIC MINERALIZATION  19  iii Page IIj  HIGHLAND VALLEY  21  INTRODUCTION  21  GEOLOGY OF MINERAL DEPOSITS  21  (a} (b) (c) (d)  Bethlehem-JA Valley Copper Lornex and Skeena Highmont .  21 25 27 30  35  CHAPTER THREE: WALL-ROCK ALTERATION  35  INTRODUCTION  36  (a) General Statement (b) Methods of Study and Terminology BETHLEHEM-JA  % 36 38  (a) Main Stage Pervasive Alteration Potassic Alteration A r g i l l i c Alteration Propylitic Alteration (b) Late Stage Alteration Zeolites Epidote (c) Sulphide Zoning VALLEY COPPER (a) Pervasive A r g i l l i c Alteration (b) Vein Alteration ( i ) Early Phase Veining Barren Quartz Veins Quartz-Potash Feldspar Veins ( i i ) Main Phase Veining Quartz-Sericite Veins Potash Feldspar Alteration ( i i i ) Late Phase Veining (c) Sulphide Zoning  41 41 42 43 44 44 46 46 49 49 51 51 52 52 52 52 53 54 54  iv Page 56  LORNEX  56 59 59 60 6l 61 62 62 63  (a) Early Stage Pervasive Alteration Propylitic Propy-Argillic Zone A r g i l l i c Zone (b) Main Stage Alteration Quartz-Sericite Alteration •' Potash-Feldspar Veining Gypsum Veining (c) Sulphide Zoning  63  SKEENA HIGHMONT ' '  63  •-'  66 66 66 69 70 70  (a) Pervasive Alteration Propylitic Alteration Propy-Argillic Alteration A r g i l l i c Alteration (b) Vein Alteration Quartz-Sericite Alteration Quartz-Potash Feldspar Veining Quartz-Tourmaline-Biotite Alteration Gypsum Veining (c) Sulphide Zoning  70 70 71 71  FACTORS CONTROLLING WALL-ROCK ALTERATION (a) (b) (c) (d)  71 74 75 76  Host. Rock Composition Intensity of Faulting and Fracturing Composition of Mineralizing Solutions Structural Levels of Ore Formation  77  SUMMARY AND CONCLUSIONS  CHAPTER FOURi  . SAMPLING AND ANALYTICAL TECHNIQUES  SAMPLE COLLECTION (a) Outcrop Sampling (b) Drill-Core Sampling SAMPLE PREPARATION  8  0 80 81 81 83 84  V  Page (a) Crushing and Grinding (b) Mineral Separation  84 84 85  ANALYTICAL TECHNIQUES. (a) Emission Spectrography (b) X-Ray Fluorescence Spectrometry Major Elements Minor Elements (c) Ion-Selective Electrodes Total-Extractable Halogens Water-Extractable Halogens (d) Atomic Absorption Spectrophotometry H F - H C I O K - H N O ^ . Digestion HNO^-HCIO^ Digestion Pre-Analytical Treatment for Hg Determination (i) Sulphide Selective Decompositions Aqua Regia H 0 -Ascorbic Acid KC10 -HC1 ?  ?  3  POTASSIUM CHLORATE-HYDROCHLORIC ACIDs LEACH FOR BEDROCK GEOCHEMISTRY (a) Cb) (c) (d) (e) (f)  86 86 86 89 89 89 91 91  93  99 99 99 99 100 100  A SULPHIDE SELECTIVE  Introduction Analytical Procedure Experimental Work and Results Discussion Applications to Geochemical Exploration Conclusions  CHAPTER FIVEj  102 102 102 102 106 111  114 REGIONAL GEOCHEMISTRY  114  INTRODUCTION  115  RESULTS  115  (a) Major Elements (b) Trace Elements (i) Introduction ( i i ) Distribution of Copper ( i i i ) Distribution of S, Rb, Sr, Cl and F  115 122 122 124 126  DISCUSSION  140  SUMMARY AND CONCLUSIONS  145  vi Page CHAPTER SIX:  147  METAL DISPERSION IN BEDROCK AROUND MINERALIZATION  14-7  INTRODUCTION  148  DATA HANDLING  148 150  RESULTS BETHLEHEM-JA  150  .  (a) Geochemical Patterns Related to Primary Lithology 150 (b) Geochemical Patterns Related to Hydrothermal Alteration 157 (c) Geochemical Patterns Related to Mineralization l6l (i) Distribution of Ore Elements l6l ( i i ) Distribution of Pathfinder Elements 163 (d) R-mode Factor Analysis 166 (e) General Discussion and Summary 171 173  VALLEY COPPER (a^ Geochemical Patterns Related to Hydrothermal Alteration (b) Geochemical Patterns Related to Mineralization (i) Ore Elements ( i i ) Pathfinder Elements . (c) R-mode Factor Analysis (d) General Discussion and Summary  179 182 182 186 186 191 193  LORNEX  Geochemical Patterns Related to Litholoty 197 Geochemical Patterns Related to Hydrothermal Alteration 200 Geochemical Patterns Related to Lornex Fault 202 Geochemical Patterns Related to Mineralization 206 R-mode Factor Analysis 209 (i) Surface samples 209 ( i i ) Subsurface samples 215 (f) General Discussion and Summary 216 (a) (b) (c) (d) (e)  HIGHM0NT  220  (a) (b) (c) (d)  Geochemical Patterns Related to Lithology 220 Geochemical Patterns Related to Hydrothermal Alteration 225 Geochemical, Patterns Related to Mineralization 225 R-mode Factor Analysis 229 235  SKEENA Distribution of Cu, Zn, Mn, CaO, Fe 0~, KgO 2  235  vii Page DISCUSSION Applications to Mineral Exploration CONCLUSIONS  CHAPTER SEVEN:  240 247 251  253  MICRO-GEOCHEMICAL DISPERSION IN MINERALS  253  INTRODUCTION  254  METHODS OF STUDY  255  RESULTS  259  (a) Biotite (b) Magnetite (c) Quartz-Feldspar  259 26l 263  DISCUSSION  263  (a) Form of Trace Elements i n Mineral Phases (b) Chemical Variations Related to Modal Composition (c) Variations Related to Chemical Composition of Mineral Phases Biotites (d) Chemical Variations Related to Mineralization ( i ) Biotites ( i i ) Magnetites ( i i i ) Quartz-Feldspar GEOCHEMICAL CONTRAST  .  265 269 275 279 279 281 -283 285  SUMMARY AND CONCLUSIONS '  287  CHAPTER EIGHT:  289  ,  ORE-FORMING PROCESSES AT HIGHLAND VALLEY INTRODUCTION (a) General Statement (b) Ore Genetic Models f o r Porphyry Copper Deposits ORIGIN OF GUICHON CREEK BATHOLITH AND SOURCE OF METALS  289 290 290 290 292  viii Page (a) Provenance of Guichon Creek Magma and Associated Metals 292 297  (b) Level of Emplacement and Volatile Pressures  300  NATURE OF ALTERATION-MINERALIZATION PROCESSES (a) Mineral S t a b i l i t y Fields  300  (b) Bedrock Geochemical Evidence  301  DISCUSSION  301  CONCLUSIONS  310  CHAPTER NINE:  311 312  SUMMARY AND CONCLUSIONS :(<a) Regional Geochemistry Cb) Detailed Bedrock Geochemistry . (c) Mineral Geochemistry (d^ Sulphide Selective Digestion Ce) Ore-forming Processes at Highland Valley (f) Applications of Bedrock Geochemistry i n Exploration  312 313 315 316 318 318  REFERENCES  322  APPENDIX A  337  B  3^9  C  361  D  378  VOLUME I I Maps depicting metal distribution patterns at Bethlehem-JA  t  Copper, Lornex, Highmont and Skeena,  Valley  ix LIST OF TABLES Table  - . .!  .  Page  I  Units and Phases of the Guichon Creek batholith.  15  II  Size production, capacity, grade and ore mineralogy of mineral deposits, Guichon Creek batholith  20  III  Summary of sampling and chemical analysis  82  IV  Spectrographic equipment and standard operating  V  Spectral l i n e s and precision a t the 95% confidence l e v e l of emission spectrographic analysis  88  VI  Operating conditions f o r P h i l i p s 1010 X-ray spectrometer  90a  VII  Equipment and stock reagents i n ion-selective electrode analysis  90b  VIII  Comparison of f l u o r i n e and chlorine contents of U.S.G.S. standard rocks  92  IX  Operating conditions f o r Techtron AA-U spectrophotometer  94  X  Operating conditions f o r the Perkin Elmer 303 spectrophotometer  95  XI  Operating conditions f o r the J a r r e l l - A s h 82-270 spectrophotometer  96  XII  A n a l y t i c a l precision of HF/HCL0^/HN0„ digestion a t the 95% confidence l e v e l estimated from paired samples  97  XIII  conditions87  Comparison of trace and major element contents of U.S.G.S. standard rocks  98  XIV  E f f e c t of composition of standards on atomic absorption  XV  Comparison of leaches on ultramafic standard UM1, UM2 and UM4 E f f e c t of amount of KCL0~ added on release of copper with KCLO^-HCl leach  108  XVII  E f f e c t of grinding on release of copper and zinc with KCIO^-HCI leach  109  XVIII  Comparison of a n a l y t i c a l r e s u l t s obtained from KC10-HC1 digests using atomic absorption and colorimetry  112  XVI  101  105  X  Page XIX  Means, ranges and mean normative composition of i n t r u s i v e u n i t s , Guichon Creek b a t h o l i t h  117  Means and ranges' of trace elements i n rocks of Guichon Creek b a t h o l i t h  123  Abundances of sulphur, rubidium and strontium i n rocks of Guichon Creek b a t h o l i t h  128  Abundances of mercury i n rocks of Guichon Creek batholith  129  XXIII Abundances of chlorine and f l u o r i n e i n rocks of Guichon Creek b a t h o l i t h  135  XX XXI XXII  XXIV  Means and ranges of trace elements at Bethlehem-JA.,-..:. - , :: -  :  :  XXV XXVI  .  151  Means and ranges of some metal concentrations i n p r i n c i p a l l i t h o l o g i c u n i t s , Bethlehem-JA 2800 Level  154  Correlation matrix of trace and major element contents, Bethlehem-JA 2800 Level  156  XXVII Chemical variations associated with types of a l t e r a t i o n , Bethlehem-JA 2800 Level  158  XXVIII Relationships among copper, potassium and potential pathfinder elements, Bethlehem-JA 2800 Level  167  XXIX  Element associations of d i f f e r e n t f a c t o r models, trace and major element content of rocks, Bethlehem-JA, 2800 Level  168  XXX  R-mode Varimax Factor Matrix,. Bethlehem-JA 2800 Level  169  XXXI  Comparison of mean icontent and geochemical contrast i n background and anomalous samples, Bethlehem-JA 2800 Level  172  XXXII Means, deviations and ranges of trace and major elements of Valley Copper  176  XXXIII Chemical variations associated with types of a l t e r a t i o n , Valley Copper 36OO Level XXXIV Correlation c o e f f i c i e n t s , Valley Copper 36OO Level XXXV  Element associations of d i f f e r e n t factor models, Valley Copper 36OO Level  180 187  188  xi Page XXXVI  Varimax Factor Matrix, Valley. Copper  XXXVII  ComparisonsCof mean element content i n background and mineralized samples,.Valley Copper 3 6 O O Level  36OO  Level  189 1 9 2  XXXVIII  Means and ranges of trace and major elements, Lornex property  1 9 6  XXXIX  Means and ranges of metal concentrations i n l i t h o l o g i c units, Lornex Surface  1 9 8  XL  Means and ranges of element abundances associated with alteration types, Lornex Subsurface  2 0 1  XLI  Metal concentrations along the Lornex Fault  204  XLII  Correlation coefficients,•.'Lornex Subsurface  2 1 0  XLIII  R-mode Varimax Factor Matrix, Lornex Surface  2 1 1  XLIV  Metal associations of different factor models, Lornex . Subsurface  2 1 2  XLV  Correlation Coefficients, Lornex Subsurface  XLVI XLVII  R-mode Varimax Factor Matrix, Lornex Subsurface 214 Comparison of v a r i a b i l i t y i n copper contents of background and mineralized samples, Lornex 2 1 8 Comparison of metal contents and contrast i n background  XLVTII  and mineralized areas, Lornex property  2 1 3  2 1 9  XLIX  Means and ranges of trace and major elements at Highmont 2 2 3  L  Means and ranges of metal concentrations i n l i t h o l o g i c units, Highmont Surface 224 Metal concentrations associated with types of alteration,  LI  Highmont property  2 2 6  LIl  Correlation matrix, Highmont Subsurface  2 3 0  LIII  Metal associations of different factor models, Highmont Subsurface 2 3 1 Varimax Factor Matrix, Highmont Subsurface 2 3 2  LIV  xii Page LV LVI LVII  Comparison of v a r i a b i l i t y i n copper contents of background and mineralized samples, Highmont  236  Comparison between metal concentrations i n background and mineralized zones, Highmont  237  Comparison of r e l a t i v e contrast and extent of halos at Highland Valley deposits  248  LVIII  Trace element and modal content of whole rock samples  258  LIX  Trace and major element contents of minerals  260  LX  Student T test of background and anomalous samples  262  LXI  KCIO^-HCI extractable metal i n mineral phases  264  LXII  Correlation matrix f o r modal analysis and trace element content of rocks and minerals Comparison of geochemical contrast i n whole rock and mineral separates  276 286  Rb, Sr, Rb/Sr, K/Rb, and S r Cordilleran intrusions  296  LXIII LXIV  8 ?  /Sr  8 6  abundances of some  xiii LIST OF FIGURES FIGURE  Page 1s  Location of study area  4  2:  Geology of Guichon Creek b a t h o l i t h  3:  Simplified modal variations i n rocks of the Guichon  16  Creek b a t h o l i t h  18  4:  Generalized geology of Highland Valley  22  5:  General geology of Bethlehem-JA, 2800 Level  24  6:  General geology of Valley Copper  26  ?:  Generalized geology of Lornex and Skeena Mines  28  8:  Simplified geology across a section at Lornex mine  29  9:  Simplified geology of Highmont property  31  10:  Simplified geology across a section at Highmont  33  11:  Generalized a l t e r a t i o n map,  39  12:  Generalized a l t e r a t i o n across a section of Bethlehem-JA  40  13:  D i s t r i b u t i o n of z e o l i t e a l t e r a t i o n at Bethlehem-JA  45  14:  Generalized sulphide zoning at Bethlehem-JA  47  15:  Generalized v e r t i c a l d i s t r i b u t i o n of sulphides at  Bethlehem-JA, 2800 Level  Bethlehem-JA  48  16:  Generalized a l t e r a t i o n map,  Valley Copper  17:  Generalized a l t e r a t i o n map,  Lornex  18:  Generalized a l t e r a t i o n i n a section across Highmont  58  19:  Sulphide d i s t r i b u t i o n at Lornex mine  64  20:  Wall-rock a l t e r a t i o n map,  65  21:  Generalized a l t e r a t i o n map,  22:  Generalized a l t e r a t i o n map  4900  3600  Level  Level  Skeena mine Highmont property i n a section across Highmont  50 57  67 68  xiv FIGURE  Page 23a: 23b:  Mineral zoning and copper grade at Highmont property  72  Distribution of MoSg i n relation to mineral zoning at Highmont  73  24s  Comparison of % of t o t a l metal extracted by p a r t i a l 104 extraction techniques  25:  Relationship between the amount of metal extracted _'il07 and time of grinding  26:  Location of samples used i n regional study, Guichon Creek batholith 116  27:  Variation diagrams i n Guichon Creek rocks showing major element concentrations versus Larsen d i f f e r entiation index  119  AFM variation diagram f o r rocks of Guichon Creek batholith  120  28: 29: 30a:  ' CaO-Na 0-K 0 variations f o r rocks of Guichon Creek batholith 121 ?  ?  Distribution of Copper i n relation to Larsen differentiation index  125  Regional distribution of aqua regia extractable copper i n rocks of Guichon Creek batholith  125  Relationship between Copper and Iron i n rocks of Guichon Creek batholith  127  Relationship between rubidium and potassium i n rocks of Guichon Creek batholith  131  Plots of K/Rb versus K i n rocks of Guichon Creek batholith  132  33s  Plots of K/Rb and Ca/Sr versus Larsen d i f f e r e n t i a tion index  133  . 34:  Variation diagrams i n Guichon Creek rocks showing trace element « concentrations plotted against LDI  137  Relationship between Iron and Zinc i n rocks of Guichon Creek batholith  138  30b: 31: 32: 32b:  A  35:  XV  FIGURE  Page 36:  Relationship between Iron and Manganese i n rocks of the Guichon b a t h o l i t h  3 7 a : Variation of Nickel '.with Iron i n rocks of Guichon Creek b a t h o l i t h 37b:  Variation of Nickel with Magnesium i n Guichon Creek b a t h o l i t h  139 141 141  3 8 a : Relationship between Cobalt and Iron i n Guichon Creek b a t h o l i t h  142  3 8 b : Relationship between Cobalt and Magnesium i n Guichon Creek rocks  142  39s  Relationship between Zinc and Magnesium contents of rocks, Bethlehem-JA 2 8 0 0 Level  40:  Flot;of Rubidium versus Potassium, Bethlehem-JA 2800 Level  41:  Plot of Strontium versus Calcium, Bethlehem-JA  42:  155 160  2800 Level  160  Log p r o b a b i l i t y plot"of Copper a t Bethlehem-JA  162  43:  Relationship between t o t a l and water-extractable Chlorine i n rocks, Bethlehem-JA, 2 8 0 0 Level 4 4 a ; Schematic diagram showing extent and r e l a t i v e i n t e n s i t y of primary halos, Bethlehem-JA 2800 Level  165 174  44b: S6hematic diagram showing d i s t r i b u t i o n of f a c t o r  45:  scores, Bethlehem-JA 2800 Level  175  Log p r o b a b i l i t y p l o t of Copper a t Valley Copper  183  46: "Relationship between Copper and Potassium a t Valley Copper 3600 Level 4 7 a : Schematic diagram showing extent and r e l a t i v e i n t e n s i t y of primary halos, Valley Copper 36OO Level  194  4 7 b : Schematic diagram showing d i s t r i b u t i o n of f a c t o r scores, Valley Copper 36OO Level  195  48: 49:  185  Plot of Barium versus Potassium i n background samples, Lornex Surface  I99  Manganese versus Iron i n unmineralized samples, Lornex Surface  I99  xvi FIGURE  Page 50:  Relationship between Mercury and Zinc along Lornex Fault  205  51:  Log probability plot of Copper at Lornex  20?  52:  Schematic diagram showing extent and r e l a t i v e intensity of primary halos, Lornex Subsurface Schematic diagram showing distribution of factor  221  scores, Lornex Subsurface  222  5^:  Log probability plot of Copper at Highmont  227  55*  Schematic diagram showing extent and relative intensity of primary halos, Highmont Subsurface 239 Schematic diagram showing distribution of factor 238 scores, Highmont Subsurface Location of rock and mineral samples, Highland Valley 256  53s  56: 57: 58: 59' 60:  Proportions of t o t a l Copper and Zinc extracted from b i o t i t e s by KCLO^-HCl digestion  266  Proportions of t o t a l Copper and Zinc extracted from magnetites by KCLO^-HCl digestion  267  Proportions of t o t a l Copper and Zinc extracted from quartz-feldspar phases by KCLO^-HCl digestion  268  6l: Relationship between whole-rock copper and modal proportions of b i o t i t e 62: 63: 64: 65: 66: 67:  270  Relationship between modal and Copper contents of biotites  271  Plot of modal b i o t i t e versus Copper from b i o t i t e i n whole rock  272  Relationship between whole-rock Copper and percent accessory minerals i n rocks  273  Covariance of Copper and modal K-feldspar in-whole rocks  274  Plot of modal b i o t i t e versus Zinc from b i o t i t e i n whole rocks '  277  Copper versus Iron i n b i o t i t e s  278  xvii FIGURE  Page 68s  Copper versus Magnesium i n b i o t i t e s  2  69s. Relationship between t o t a l Copper i n whole rocks and b i o t i t e s 70s 71: 72: 73*  78  280  Relationship between Copper contents of whole rocks and magnetites  282  Relationship between Copper contents of whole rocks and quartz-feldspar f r a c t i o n s  284  Plot of Potassium versus Rubidium and K/Rb r a t i o s / i n rocks of Guichon Creek b a t h o l i t h  293  Plot of Rubidium versus Strontium i n rocks of Guichon Creek b a t h o l i t h  294  74:  Plot of normative Ab-Or-Qz proportions f o r the Guichon Creek samples compared with boundary curves and minima at 2, 4, 7 and 10 kb P„ _ 298  75s  Gain and l o s s of p r i n c i p a l rock constituents through a l t e r a t i o n and mineralization, Valley Copper  H0 2  76:  302  Model f o r chemical and mineral zoning and evolution of ore-forming f l u i d s  307  77:  Location of samples, Bethlehem-JA Suboutcrop Level  338  78:  Location of samples, Bethlehem-JA 2800 Level  341  79:  Location of samples, Bethlehem-JA 2400 Level  346  80:  Location of samples, Valley Copper Suboutcrop Level  350  81:  Location of samples, Valley Copper  82:  Location of samples, Valley Copper, 3300 Level  83:  Location of samples, Lornex Surface ( i n poefeet-)Comb**  352  84:  Location of d r i l l - c o r e samples, Lornex mine  369  85:  Location of samples, Highmont Surface ( i n $oek-ek) Cohi^379  86:  Location of d r i l l - c o r e samples, Highmont property  36OO Level  353 (  358  392  LIST OF FIGURES VOLUME I I (Maps depicting trace and major element dispersions around mineralization) Bethlehem-JA (2800 Level except where indicated) FIGURE Al  Zinc  A2  Manganese  A3  Titanium  A4  Vanadium  A5  Magnesia  A6  Silica  A7  Potash  A8  Rubidium  A9  Barium  A10  Calcium  All  Strontium  A12a Rubidium/Strontium A12b Barium/Strontium A13  Soda  Al4  Iron  A15  Copper (Suboutcrop Level)  A16  Copper (2800 Level)  A17  Copper (2400 Level)  A18  Sulphide Copper  A19  Sulphide Iron  A20  Molybdenum  FIGURE A21  Sulphur  A22  Mercury  A23  Boron  A24  Chlorine  A25  Water-extractable  A26  Fluorine  A2?  Water-extractable  A28  Factor R-l  A29  Factor R-2  A30  Factor R-3  A31  Factor R-4  chlorine  Fluorine  VALLEY COPPER (36OO Level except where indicated) FIGURE  A32  Zinc  A33  Manganese  A34  Manganese (3300 Level)  A35  Strontium  A36a Barium A36b  Barium/Strontium  A37  Magnesia  A38  Iron  A40  Calcium  Aki  Soda  Ak2  Rubidium  A43  Potash  Akk  Rubidium/Strontium  A45  Silica  FIGURE  A46  Copper (Suboutcrop)  A47  Copper (3600)  A48  Copper (3300)  Akg  Sulphide Copper  A50  Sulphide Iron  A51  Molybdenium  A52  Sulphur  A53  Boron  A54  Chlorine  A55  Fluorine  A56  Factor R-l  A57  Factor R-2  A58  Factor R-3  A59  Factor R-4  Lornex (Subsurface, except where indicated) A60  Zinc  *A60b Zinc (Surface) A6l *A6lb A62  Iron Iron (Surface) Manganese  *A62b Manganese (Surface) A63a  Strontium  A63b  Calcium  A64  Sodium  A65a Barium A65b  Potash  FIGURE  A66  Silver  A67  Lead  A68  Cadmium  *A69  Copper (surface)  A70  Copper  ATI  Molybdenum  *A71b  Boron (surface)  A72  Factor R-l  . A73  Factor R-2  A74  Factor R-3  A75  Factor R-4  'Subsurface except where : A?6  Zinc  A77  Manganese  A78  Iron  A79  Soda  *A80  Copper (surface)  A81  Copper  A82  Molybdenum  *A83 A84  Boron (surface) Boron  - A85  Factor R-l  A86  Factor R-2  A87  Factor R-3  A88  Factor R-4  XXII  FIGURE  A89  Factor R-5  A90  Copper, Zinc,. Manganese  A91  Calcium, Iron, Potash  Skeena FIGURE  *  'Eft $uToes'in- S p e c i a l C o l l e c t i o n s :  Gxtome-t  xxiii LIST OF PLATES PLATE  Page 1;  Conglomeration of (?) secondary perthitic K-feldspar i n Bethlehem quartz d i o r i t e of the potassic zone, Bethlehem-JA  78  2: Sericite alteration of plagioclase and a l k a l i feldspars i n potassic zone of Bethlehem-JA '' " 78 3: Coarse-grained sheaves of interlocking chlorite i n the propylitic zone of Bethlehem-JA 4:  5:  Medium- to coarse-grained crystal, of epidote (veinf i l l i n g material) i n the propylitic zone of Bethlehem-JA  78  Pervasive s e r i c i t e (+ minor kaolinite) and quartz remnants i n the a r g i l l i c zone of Valley Copper deposit  78  6: Alteration of coarse b i o t i t e grains to fibrous s e r i c i t e i n the a r g i l l i c zone of Valley Copper deposit 7:  78  78  Very coarse grained s e r i c i t e (vein material) i n the phyllic zone of Valley Copper deposit  79  8:  Fine-grained epidote p a r t i a l l y replacing a b i o t i t e grain i n propylitized rock of Lornex mine  79  9:  Fine to medium-grained s e r i c i t e and kaolinite i n the a r g i l l i c zone of Lornex mine  79  10:  Quartz and chlorite replacements of a b i o t i t e grain i n the; propylitic zone of Highmont deposit  79  11:  Weak a r g i l l i z a t i o n of plagioclase (with minor carbonate) at Highmont property 79  12:  Radiating tourmaline crystals (schorl) i n a breccia matrix at Highmont  79  13 s Disseminated?s.ulphide grains (mainly bornite with minor chalcopyrite) i n mineralized samples at Highmont (reflected l i g h t )  288  14: Bornite inclusions i n chloritized b i o t i t e (a) transmitted l i g h t (b) reflected l i g h t  288  15:  Opaque grains (sulphide) occurring at the margins of a chloritized b i o t i t e (transmitted l i g h t )  288  ACKNOWLEDGEMENTS  This research project formed part of the applied geochemistry research programme being undertaken at the Geological Sciences Centre, U.B.C., under the direction of Dr. W.K. Fletcher, to whom the writer i s grateful for suggesting, actively supervising and channeling generous funds for the thesis. Grateful acknowledgement i s made to A. Dhillon, D. Marshall, and M. Waskett-Myers for analyzing many, of the samples.  Able  assistance was provided i n the f i e l d by P. Marcello and M. WaskettMyers . I wish to thank members of the mining industry - notably Bethlehem Mining Corporation, Canex Placer, Cominco, Highmont Mining Corporation, Lornex Mining Corporation, and Quintana Minerals Exploration for providing access to their properties and for financial and material assistance. S p e c i f i c a l l y , I wish to mention, R.F. Anderson and P.P. Tsaparas (Bethlehem Mining Corporation), J.M. Allen and M. Osatenko (Cominco), A. Reed (Highmont Mining Corporation), M. Skopos, G. Walden and G, Smith (Lornex Mining Corporation), and W.J. McMillan (B.C. Dept.of Mines). I am thankful to Drs. A.J, S i n c l a i r , A, Soregaroli, K.C. McTaggart, W.J. McMillan and T. Brown for constructive c r i t i c i s m of earlier drafts of the thesis.  I am indebted to my colleagues, Messrs,  P. Doyle, S. Hoffman and R. Lett f o r useful discussions of geochemical and s t a t i s t i c a l problems. Financial support for the project was provided partly by  the National Research Council of Canada (PRAI Grant # P-7303) and NRC Grant 67-7714 awarded to Dr. K. Fletcher.  During t h i s  investigation, I benefited from various fellowships f o r which I am grateful.  CHAPTER ONE INTRODUCTION  2  GENERAL STATEMENT Bedrock geochemistry, as a tool i n detailed mineral exploration, i s s t i l l i n an experimental stage (Hawkes and Webb, 1962; Boyle, 1 9 6 7 ) .  According to Boyle and Garrett ( 1 9 7 0 ) , research on  the nature and extent of primary halos around specific types of mineral deposits i s required'to establish bedrock geochemistry as a practical exploration technique. Porphyry-type deposits are major sources of copper and molybdenum i n the Canadian Cordillera and other parts of the world. Compared with other types of deposits, such as massive sulphides (Shikawa et a l . , 1962, 1974; Sakrison, 1971; Nairis, 1971; Pantazis and Govett, 1973; Goodfellow, 1974; Thurlow, 1974) or veintype mineralization (Boyle, I96I, I965, I968;  Bolter and Al-Shaieb,  1971;  Ineson, I969, 1970; Dass et a l . , 1 9 7 3 ; Bailey and McCormick,  1974),  r e l a t i v e l y less research work has been undertaken or published  on lithogeochemic'al halos around porphyry-type deposits (see Coope, 1973).  However, notable exceptions are the recent studies of  Theodore and Nash (1973) on trace element; dispersion around the Copper Canyon deposits, Oyarzun et a l . (1974) on primary halos of Rb and Sr around Chilean prophyry copper deposits, Warren et a l . (1974) on Ba and Sr dispersion i n wallrocks of the Island Copper deposit i n B.C., and Gunton and Nichol ( 1 9 7 4 ) , The porphyry copper-molybdenum deposits of the Guichon  3  Creek batholith (Valley Copper, Bethlehem-JA, Lornex and Highmont) were chosen for this investigation by virtue of their economic significance and the availability of previous studies of geology and geochemistry by Northcote (1969) and Brabec (1970) respectively. Their location in an easily accessible area of southern British Columbia (Fig. l ) and the relative abundance of outcrops and d r i l l cores, were further advantages. LOCATION AND ACCESS The Highland Valley district is located in the central part of the Guichon Creek batholith, approximately 250 miles northeast of Vancouver, B.C. (Fig. l ) .  Main access to the area is pro-  vided by a 28 mile,'paved secondary road from the town of Ashcroft, and from the east, through Logan Lake, a small mining town recently developed by Lornex Mining Corporation. As a result of intensive mining and exploration activities, the entire Highland Valley district is easily accessible by numerous un paved roads and trails. OBJECTIVES OF STUDY Objectives of this study are toj (1) determine the nature, extent and factors controlling epigenetic dispersion of major and trace elements ln wall rocks surrounding porphyry copper-molybdenum deposits. (2) determine relationships between distribution of Cu and potential pathfinders, such as Hg, Gl, F, B, and Rb and Sr.  4  FIGURE 1:  Location of Study Area  5  (3) investigate, and i f appropriate, develop partial extraction techniques as a means of selectively extracting sulphide Cu, and thereby improving geochemical contrast between anomalous and background areas* (4) assess the value of chemical analysis of constituent minerals, rather than whole rocks, in improving contrast between anomalous and background environments* , BEDROCK GEOCHEMISTRY IN MINERAL EXPLORATION - PREVIOUS WORK Use of bedrock geochemistry as an exploration tool grew largely from the work of A.E. Fersman and his colleagues in the U.S.S.R. in the early part of this century.  Since their pioneer  work, considerable research and refinement of the technique have been undertaken in the U.S.S.R. and other parts of the world. Boyle and Garrett (1970), Sakrison  (1971)  and Coope  (1973)  have recently  reviewed the status of lithogeochemistry in mineral exploration. The following review of relevant literature emphasises the results of studies on exploration for porphyry copper deposits. The review is subdivided into three sections» surveys;  (l) regional geochemical  (2) detailed chemical and mlneralogical patterns around  ore deposits; and (3) micro-dispersion of trace metals ln mineral phases* (a) Regional Geochemical Patterns Various types of mineral deposits, including porphyry coppers, are believed to be genetically related to their host rocks  6  (Krauskopf, 1967)•  Consequently, numerous bedrock geochemistry  studies have been focussed on differentiating barren from potentially ore-bearing lntrusives. Goldschlmdt (195*0 assembled a vast amount of data on trace element abundances in crustal rocks, and devised 'rules' that govern their behaviour in silicate melts. A critical review of this subject is presented by Burns and Fyfe (1967). Empirical data on systematic variations of trace elements during magmatic differentiation have been presented by Wager and Mitchell (1951) and Wager and Brotm (1967) for the Skaergaard intrusion, and other differentiated igneous suites (Cornwall and Rose, 1957!  McDougall and Lovering, 1963). Warren and Delavault (i960) found that aqua-regia-extr-  actable Cu in plutons containing porphyry Cu deposits (including Guichon Creek batholith) was appreciably higher than in barren lntrusives of similar composition. Brabec and White (1971) investigated the distribution of aqua-regia-extractable Cu and Zn in more than J00 fresh samples from the Guichon Creek batholith*  Their results indicate a general  decrease in Cu and Zn from the outer margins to the central zone where rock phases containing the main porphyry Cu deposits are impoverished in Cu.  They concluded that, a relatively high Cu  content of an intrusive phase is not necessarily indicative of its superior ore potential. Kesler et al* (1973)» using ion-selective electrodes,  7  evaluated the possible use of water-leachable Cl and F in 'fingerprinting* intrusions that are potentially ore-bearing. Their sampling included two porphyry-copper-bearing intrusives, plutonic bodies with associated contact deposits and other barren intrusions in the Caribbean and Central America. The results, which are a measure of the abundance and concentration of fluid Inclusions and other water-soluble rock constituents, do not indicate there is any simple relation between abundance of Cl and the occurrence of mineralization. However, average F values are higher in mineralized than unmineralized Intrusion. Rabinovich et a l . (1958) and Tauson et a l . (1970) reported that the Mo contents of intrusives that carry Mo mineralization in the U.S.S.R. are not higher than those of barren plutons of similar composition. (b) Hydrothermal Dispersion Patterns Metasomatism of ore and associated metals into country rock during metallization is instrumental in the development of hydrothermal dispersion patterns in wall rocks of mineral deposits. Hawkes and Webb (1962) and Bradshaw et a l . (1970) have discussed the factors controlling epigenetic dispersion patterns. Theodore and Nash (1973) studied the distribution of 20 trace elements in wall rocks surrounding the Copper Canyon porphyry copper deposits. The orebodies are localized within metasedimentary rocks intruded by a relatively barren granodiorite stock. They  8  found that concentrations of Cu  Mo and other trace elements were  t  higher in the barren intrusion than in the mineralized metasediments. Thus they oonclude that a geochemical anomaly of Cu in bedrock does not necessarily coincide with Cu ore at Copper Canyon, Armbrust (1971) and Oyarzun et a l . (197*0 found that Rb i s enriched and Sr depleted in central zones of intense potassic alteration and mineralization at several Chilean porphyry Cu deposits. Warren et a l . (1974) reported that Ba and Sr values are depleted in ore zones of the Island Copper deposit i n British Columbia. Davis and Guilbert (1973)i investigating radio-element (K, U, Th) distribution in several porphyry-type deposits in southwest U.S.A. found that in mineralized plutons, enhanced K and U levels are centrally located and spatially associated with intense potassic alteration and mineralization. Thus, they conclude that radiometric measurements of K and U are viable tools i n the search for porphyry-type deposits. Gunton and Nichol (197*-) studied the distribution of 18 2  major, minor and trace elements in volcanic and plutonic rocks associated with the Ingerbelle and Copper Mountain Cu deposits.  On  a reconnaissance basis, they found that increased contents of P, Rb and Sr and to a lesser extent Na and K in volcanic rocks adjacent to the ore-bearing Copper Mountain stock.  On a local scale, a broad  zone of Na enrichment i s associated with intense alteration at Ingerbelle deposit as opposed to localized zones of K enrichment in the Copper Mountain deposits.  9  Mineralogical zoning patterns around porphyry Cu deposits have been investigated by numerous workers, notably, Lowell and Guilbert (1970), Rose (1970), Nielsen (1968) and Carson and Jambor (1974).  Hausen and Kerr (1971) employed X-ray diffraction methods  in outlining distribution of alteration minerals in porphyry Cu-Mo deposits in Arizona, Montana and Washington. They conclude that alteration patterns correlate with the distribution of Cu and  Mo,  and permit the projection of previously unknown mineralization. (c) Mineral Geochemical Patterns The trace element contents of various mineral phases have been utilized i n the exploration of porphyry Cu deposits.  The basis  for these applications i s that constituent minerals might better reflect the presence of mineralization or give better geochemical contrast than whole rocks. Parry and Nackowski  (1963) found that Cu contents of  biotites from Intrusions in porphyry Cu areas tended to be relatively high.  Similar conclusions were reached by Putman and Burnham (1963)  and Graybeal (1973) i n their studies of Cu contents i n biotites and hornblendes of plutonic rocks in Arizona.  In the Sierrita and Santa  Rita Mountains of southern Arizona, rocks from Intrusions that are genetically associated with Cu deposits- contain as much as 300 p.p.m., whereas biotites separated from these rocks contain as much as ~L% Cu.  Lovering et a l . (1970)* therefore conclude that Cu anomalies  in biotite provide a more reliable guide to Cu mineralization than  10  do whole rocks. Al-Hashimi and Brownlow (1970) reported relatively high Cu contents i n biotites from mineralized Boulder batholith . 7  This  enrichment i s attributed to the presence of epigenetic sulphide i n clusions.  However, the authors conclude that because of the erratic  distribution of Cu i n biotites, bedrock provides a better and more consistent guide to mineralization. Parry (1972) found no clear distinction between the Cl content of biotites and their occurrence i n mineralized or barren plutons, except that biotites with less than 0,2% (31 came from plutons with l i t t l e or no Cu mineralization. Hamil and Nackowski (1971) investigated magnetites from several lntrusives i n Utah and Nevada, and found that low abundances of Ti and Zn in magnetite correlate with major porphyry Cu mineralization.  Theobald and Thompson (1962) noted that magnetite from  rocks presumably associated with Cu mineralization at Butte, Montana are relatively impoverished in Zn.  In contrast, high con-  centrations of Cu and Zn were reported by de Grys (1970) i n magnetite from lntrusives associated with porphyry Cu mineralization. Stanley (1964) found that the Cu contents of wall rocks i n the Granduc deposit in B.C. were not related to the proportion of magnetite.  Huff (1971)  found no significant/Cu anomalies i n magnetites derived from lntrusives associated with Cu mineralization l n the Lone Star d i s t r i c t in Arizona.  11  In conclusion, various workers have obtained different results using similar techniques*  This emphasizes the need for  studies to be carried out in different environments.  Lines of  further productive research involve the use of minor and trace elements, such as Rb, Sr, and Ba, and volatlles in delineating zones associated with hydrothermal alteration and mineralization in porphyry copper deposits.  CHAPTER TWO GEOLOGIC SETTING OF GUICHON CREEK BATHOLITH  13  I.  GUICHON CREEK BATHOLITH  REGIONAL SETTING The Guichon Creek batholith i s a concentrically zoned, granitoid pluton, elongated slightly west of north, underlying an area of approximately 480 square miles.  It intrudes sedimentary  and volcanic rocks of the Permian Cache Creek and Upper Triassic Nicola Groups, within a tectonic setting that i s considered either eugeosynclinal (Danner and Nestall, 1971) arc couple (Dercourt, 1972?  or as an oceanic-island  Monger et a l . , 1972). The batholith  i s overlain unconformably by Middle Jurassic to Tertiary volcanic and sedimentary rocks, and bounded on the west and east by faults of regional extent (Carr, 1962). The age of the batholith has been determined precisely by stratigraphic and geochronometric methods. Forty-five K-Ar (Folinsbee^et a l . , 1965! 1964;  Baadsgaard et a l . ,  Wanless et a l . , 1965s 1968;  Blanchflower, 1971;  1961;  Dirom, 1965;  Leech et a l . ,  Northcote, 1969;  Jones et a l . , 197 ) and two Rb-Sr (Chrismas 2  et a l . , 1969) age determinations on rocks from the batholith indicate that the various igneous phases are, within limits of analytical error, 200 m.y. old. However, geoglogic evidence presented by Northcote (1969) suggests that the zoned pluton i s progressively younger from the border inward.  Rocks of the batholith have not  undergone any significant metamorphlsm since emplacement.  14  PETROLOGY AND STRUCTURE Petrology of the Guichon Creek batholith has been described by numerous workers, notably White et a l . , (1957)» Carr (1966), Northcote (1969), McMillan (1972) and Hylands (1972). The batholith Is composed of nine igneous phases delineated by variations i n texture (Table I and Fig. 2). These phases, which vary l n composition from diorite to quartz monzonite are grouped into units on modal similarities and contact relations (Hylands, 1972). Border Unit forms the outer zone of the batholith, and i s composed of hybrid, highly variable to uniformly fine-grained diorite that i s commonly enriched i n mafic minerals. Highland Valley Unit, which comprises the Guichon and Chataway Phases, forms a complete ring within the Border Unit (Fig. 2).  Medium-grained Guichon quartz diorite i s characterized by  anhedral quartz grains and unevenly distributed clusters of mafic minerals.  Average modal composition i s estimated by Northcote (1969)  as follows:  plugioclase (An^-j^g) constitutes 50%$ orthoclase 1Q£,  quartz 16$, biotite and hornblende 17%» pyroxene and accessory minerals % •  The equigranular Chataway granodiorite i s character-  ized by evenly distributed equant grains of hornblende and biotite which both constitute 12% of the mode (McMillan, 1972). Intermediate Unit l i e s between the Highland Valley Unit and the core of the batholith.  It i s composed of the Bethlehem and  Skeena granodiorites and Witches Brook and Bethlehem Porphyry dykes. The Bethlehem and Skeena granodiorites are characterized by randomly  TABLE  IJ  Units and phases of the Guichon Creek batholith (Modified after, Northcote, 1969i  PHASES  UNITS  Hylands, 1972;  McMillan,.1972).  ROCK TYPES MODS OF EMPLACEMENT  Core  Intermediate  Highland Valley Border  Gnawed Mountain  dacite to quartz l a t i t e porphyry  dyke  Bethsaida  granodiorite to quartz monzonite  epizonal-plutonic  Bethlehem Porphyry  l a t i t e , dacite, quartz diorite, microgranite  dyke  Witches Brook  granodiorite to quartz monzonite .  dyke  Skeena  quartz d i o r i t e to granodiorite  epi-mesozonal-plutonic  Bethlehem  quartz d i o r i t e to granodiorite  mesozonal-plutonic '  Chataway  quartz d i o r i t e to granodiorite  mesozonal-plutonic  Guichon  quartz d i o r i t e to granodiorite  mesozonal-plutonic  Hybrid  diorite to quartz diorite  mesozonal-plutonic  RELATIVE AGE youngest  oldest  16  FIGURE  Geology of Guichon Creek batholith (Modified after McMillan, 1972)  17  distributed, coarse, p o i k i l i t i c hornblende crystals, set in a matrix of fine- to medium- grained f e l s i c minerals.  However, the  Skeena differs from the Bethlehem granodiorite i n possessing coarsegrained, subhedral quartz phenocrysts and i n t e r s t i t i a l , ragged micro-perthite. k%  %  An estimated modal composition i s :  orthoclase 10%,  plagioclase  quartz 23$, and mafic minerals 8% (Northcote,  1969). Rocks of the Witches Brook and Bethlehem Porphyry Phases occur as dykes and small stocks with varying mineralogy and texture (Table I ) . Gore Unit comprises the Bethsaida and Gnawed Mountain Phases.  The Bethsaida granodiorite to quartz monzonite i s coarse-  grained, commonly porphyritlc and consists of subhedral phenocrysts of quartz (16 - k%),  plagioclase (38 - 57%),  i n t e r s t i t i a l micro-  perthite (5 - l¥>) and coarse biotite "books" (3-7%)  (Northcote,  1969)» Rocks of the Gnawed Mountain Phase occur mainly as porphyry dykes with varying texture; plagioclase and quartz phenocrysts are set i n an a p l i t i c groundmass. constitute less than %  Mafic minerals, mainly biotite,  of the mode.  Variations i n mineralogical composition within the constituent rock units of the batholith are depicted i n Fig. 3*  Horn-  blende, anorthite content of plagioclase, accessory minerals and biotite decrease, whereas quartz content increases from the border to core of the pluton. Pyroxene Is not found in rocks younger than the Highland Valley Unit. K-feldspar shows no systematic variations throughout the batholith.  Textural change i s manifested by increasing  FIGURE 3:  Simplified modal variations in rocks of the Guichon Creek Batholith (Data partly from Northcote, 1969); *Highly variable composition.  19  grain size toward the core.  Specific gravity of rocks also decreases  inwards (Northcote, 1969). Structurally, the batholith i s a semi-concordant dome dipping steeply on a l l sides, (Northcote, 1969). Geophysical evidence (Ager et a l . , 1973) suggests that, at greater depths, the batholith i s a flattened funnel-shaped struciurefeslightly t i l t e d to the west. Structural features within the batholith include minor and major faults, prominent among which are the 16 km long, northtrending Lornex Fault and the west-northwest trending Highland Valley Fault (McMillan, 1972).  Other local structural elements with a  predominant northerly trend, include lineaments, fractures, breccia pipes and dyke swarms. These probably a l l result from stress patterns imposed by the underlying basement (Bergey et a l . , 1971) or pressure from the intruding magma. ECONOMIC MINERALIZATION The Guichon Creek batholith i s host to several large producing and pre-producing porphyry copper deposits.  Lornex, Bethle-  hem-Hues t is and Bethlehem-Jersey mines are presently l n production; Valley Copper, Highmont, Trojan (South Seas), Bethlehem-Iona, Bethlehem-JA and Alwin are i n advanced stages of production planning, whereas East Jersey and Skeena have been mined out.  Aggregate tonnage  of these deposits exceeds 1.8 b i l l i o n tons of material grading approximately 0.4% Cu equivalent (Table II). Other prospects and showings abound i n the Highland Valley d i s t r i c t .  Although Craigmont,  TABL3. I I :  S i z e , production deposits,  capacity, grade and  Guichon Creek b a t h o l i t h (Data from Canadian Mines  Handbook, 1 9 ? 1 -  1972,  and Northern Miner Press)  Tonnage X 1 0 °  Bethlehem - East  Jersey  ore mineralogy of m i n e r a l  Production tons/day  3  Grade o f %  Cu  MoS„  Principal Minerals  1.14 .  bornite  0.60  bornite,  chakopyrite chalcopyrite  Bethlehem -  Jersey  30  Bethlehem -  Kuestis  26  O.65  bcrnite,  10.2  0.53  chalcopyrite,  Bethlehem - Iona Bethlehem - Lake Zone V a l l e y Copper  16,000  0.48.  190  bornite,  Lornex  293  Highmont*  150  0.28  0.01.5  Bethlehem-JA  300  0.45  0.017  3 8 , 0 0 0  0.-43  35-5  0.37  17.4  0.75  Alwin  1.2  2.31  Skeena  0.15  3.50  Trojan  (South Seas)  Craigmont  •14.6  * Highmont comprises two  bcrnite  chalcopyrite  0.48  1000  Krain  Ore  5,600  chalcopyrite, bornite, molybdenite chalcopyrite, bornite, molybdenite chalcopyrite, bornite, molybdenite chalcopyrite (bornite) chalcopyrite  (bornite)  bornite ' chalcopyrite chalcopyrite  1.72  major d e p o s i t s . o  21  a producing mine located immediately south of the batholith, i s a pyrometasomatic deposit, i t i s regarded as genetically related to Guichon Greek batholith (Chrismas et a l . , 1969;  A.J. Sinclair, oral  communication)• Most of the orebodiescare localized within intense zones of shattering and brecciation, usually along or near contacts between intrusive units or i n the vicinity of porphyry dyke swarms and breccia pipes. Principal ore minerals are bornite, chalcopyrite and molybdenite which occur as fracture f i l l i n g s , either within quartz and quartz-carbonate veins or clay/sericite gangue, and as disseminations within altered host rocks. II.  HIGHLAND VALLEY  INTRODUCTION The following discussion of geology at Highland Valley is based solely on the work of McMillan (1971. 1972, 1973;  oral  communications) and private company reports. However, these sources have been corroborated by f i e l d observations while collecting rock samples and petrographic examination >of relevant thin sections• General geology of the Highland Valley and location of deposits are shown i n Fig, k, GEOLOGY OF MINERAL DEPOSITS (a) Bethlehem-JA The recently discovered Bethlehem-JA deposit contains estimated reserves of more than 30° million tons of 0A%  Cu. The  22  Fg iure 4 GENERAL Z IED GEOLOGY OF H G IHLAND VALLEY(After K\N  I B L l Bethlehem phase  Volcanic flow rocks  I G I Guichon phase  1 C 1 Clastic sedimentary rocks GUICHON CREEK I BSl Bethsaida | S I Skeena  McMillan, 1973)  'LEGEND  TERTIARY  \jM_j Porphyry dykes  BATHOLITH and Gnawed Mountain  phase  I BQl Bethlehem phase with quartz eyes  Breccia bodies  phases c •  J Outline of orebody Fault-proven, inferred  23  orebody i s approximately 900 by 400 m, with i t s long axis striking east-west.  It i s localized along the contact between quartz diorite  of the Guichon Phase and  granodiorite of the younger Bethlehem  Phase, within and north of a small quartz latite porphyry dyke (Fig. 5).  In thin section, the porphyry consists of phenocrysts of  plagioclase, K-feldspar and quartz, set i n a fine-grained groundmass. Results of modal analysis (1000 counts) of three samples are as follows»  plagioclase (42 - 47%), orthoclase (18 - 23%), quartz (25 -  28%) and biotite (2 - 3%).  Except for higher content of quartz  adjacent to the porphyry, rocks of the Bethlehem and Guichon Phase are not different i n composition from those described by Northcote (1969). Structurally, the deposit i s characterized mainly by north and northwest-trending faults and fractures.  Most prominent of these  faults i s the northwest-trending 'JA* or 'Brook* Fault (Figs. 4 and 5).  , Economic mineralization i s most intense along the  shattered contact between the Guichon and Bethlehem Phases, although approximately two-thirds of the orebody l i e within the latter. Principal ore minerals are chalcopyrite, bornite and molybdenite which occur as veins, veinlets (1 - 5 mm wide), fracture coatings and disseminations. minerals•  Pyrite and specularite are the only other metallic  25  (b) Valley Copper Valley Copper orebody has a roughly e l l i p t i c a l plan of approximately 1000 by 1300 m, with the long axis striking northwesterly (Allen and Richardson, 1970),  It contains more than 1  b i l l i o n tons of 0.48$ Cu, The deposit i s situated entirely within porphyritic granodiorite to quartz monzonite of the Bethsaida Phase (McMillan, 1972) (Fig, 6), Local textural and mineralogical variants include mafic patches enriched in biotite and magnetite, and conspicuously porphyritic zones with a p l i t i c matrix.  Other volume-  t r i c a l l y insignificant rock types include small pre- and post— ore felsite and lamprophyre dykes.  Jones et a l . (1972) obtained a K-Ar  age of 132 m.y. on a post-ore lamprophyre dyke. Structurally, the deposit l i e s west of the Lornex Fault, near i t s junction with the west-trending Lake and Highland Valley Faults (Fig. 6). Carr (1967) considers the Valley Copper and Lornex deposits as segments of the same orebody that were offset by postore movement on the Lornex Fault.  According to McMillan (1971), two  dominant fault systems are evident i n the underground working; one striking south-southeast with* steep northeasterly dips, and one sub-horizontal set. Ore-grade mineralization i s localized within zones of intense shattering and brecciation.  Bornite, chalcopyrite and  molybdenite are the principal ore minerals. P y r i t e , sphalerite and hematite are relatively uncommon, but up to 2fo specular hematite  Sample  FIGURE 6:  location  General geology of Valley Copper (After McMillan, 1971 . 1973).  27  occurs within the deposit (Allen and Richardson, 1970). (c) Lornex and Skeena Lornex ore deposit i s 500 x 1300 m with an e l l i p t i c a l outline in which the long axis i s oriented north-westerly. Currently in production, i t s ore reserves exceed 300 million tons of about 0.43% '..Cu and 0.014% MoSg. The orebody lies mainly within the Skeena granodiorite adjacent to a contact with Bethsaida quartz monzonite (Fig. 7). Skeena granodiorite i s medium to coarse grained and composed of anhedral quartz, plagioclase (An^Q.^), coarse p o i k i l i t i c hornblende, biotite and i n t e r s t i t i a l perthitic orthoclase. Modal proportions as estimated from eight samples are?  plagioclase (58 -  65%), orthoclase (5 - 14%), quartz (18 - 25%), biotite (3 - 6%), hornblende ( 2 - 5 % ) and accessories (1 - 2 % ) . Bethsaida granodiorite i s characterized by coarse-grained subhedral quartz phenocrysts (23 - 30%), plagioclase (54 - 65%), i n t e r s t i t i a l orthoclase (6 - 15%), coarse biotite (2 - 7%), hornblende (3%) and accessory minerals (3%). Near the southern end of the deposit, a quartz-plagioclase porphyry of the Gnawed Mountain Phase intrudes the Skeena granodiorite (Fig. 7).  The porphyry i s  composed of large crowded phenocrysts of anhedral quartz and plagioclase, set in an a p l i t l c groundmass. include small aplite and felsite dykes.  Other minor rock types Subsurface geology of a  section across the orebody i s presented i n Fig. 8.  28  +  + +  [ Quartz porphyry  j...j  Bethsaida  | S | Skeena £3?  granodiorite granodiorite  Ultimate  pit outline  Contact  S Fault v. 2~  0  r  e  b o c |  2000ft  y 250  FIGURE 7:  500m  Generalized geology of Lornex and Skeena mines (After Lornex mining s t a f f ) .  FIGURE 8:  Simplified geology across a section at Lornex mine (P = Quartz porphyry:, B = Bethsaida granodiorite; S = Skeena granodiorite).  30  Structurally, the Lornex orebody i s bounded on the west by the Lornex Fault dipping west at 80 - 85°. Faults are numerous within the orebody (Fig. 7)» and exhibit three main trends, north, east and northwest}  a l l with moderate to steep dips. Several of  these faults are characterized by wide zones of gouge and breccia. Ore-grade mineralization occurs within intensely brecciated zones and along contacts between rock phases. The porphyry dyke i s only weakly mineralized.  Principal ore minerals are chalcopyrite,  bornite and molybdenite, although minor amounts of chalcocite, pyrite and covellite have been reported (McMillan, 1972). Main modes of occurrence are;  as fracture f i l l i n g s , i n quartz-carbonate  veins up to 10 cm wide, and disseminations i n altered host rock. Molybdenite tends to occur separately, i n quartz veinlets and "moly-slips" on fault planes. The Skeena Mine i s a vein-type deposit i n a porphyry copper environment.  It i s localized along a major, north-trending,  50 m-wide shear zone within rocks of the Skeena Phase (Fig. 7). Ore minerals Include chalcopyrite, pyrite and malachite in quartzcarbonate veins, (d) Highmont The Highmont deposits comprise five low-grade mineralized zones lying on either side of a porphyry dyke, of the Gnawed Mountain Phase (Fig. 9).  The zones have maximum dimensions of 360 to 1100 m  and are oriented sub-parallel to the west-northwest trending dyke. Grade of mineralization i s approximately 0.3% Cu and 0.015% MoSg  fpk]  Breccia  1V1  Quartz porphyry . Porphyritic. granodiorite  A  CJ) x  Generalized Pit out] line and Ore zone Geologic boundary  |'>\'| Bethsaida granodiorite ;  s~l Skeena granodiorite  FIGURE 9:  2000 ft  Simplified geology of Highmont Property (After Bergey et a l . 1971)  i—  1  32  (Table I ) .  Estimated reserves are in the range of 150 million tons. The Highmont property i s underlain primarily by quartz  diorite to granodiorite of the Skeena Phase (Fig. 4).  The contact  with the Bethsaldagranodiorite crosses the westernmost part and a 120 m wide composite dyke extends 3 km eastward from this contact across the property (McMillan, 1972)J(Fig. 9).  The dyke consists  of porphyritic granodiorite which i s cut by irregular porphyry bodies and local offshoots which extend as dykes Into the surrounding Skeena quartz diorite.  Modal analysis of four samples of the  porphyritic granodiorite Indicates a variable composition as followst ioclase  anhedral quartz phenocrysts ( 20 - 28%),  (52 - 60%),  orthoclase  (4  and accessory minerals (1 - 2%).  -lift),  subhedral plag-  coarse biotite  (5-9%)  The quartz porphyry i s similar  in mineralogy to that described at Lornex.  Breccia zones within  the dyke are composed of angular and rounded fragments of Skeena quartz diorite and porphyry, set i n an autoclastic matrix of finely comminuted rock and mineral fragments and tourmaline (schorl). Several of the fragments were veined by quartz prior to brecciation. Skeena and Bethsaida Phases are similar.to those described for Lornex.  Other rock types within the property include aplite and  lamprophyre dykes.  Subsurface geology across a section of the  property i s presented ln Fig, 10. Structurally, the Highmont deposits are characterized by numerous north-northwest, north and north-northeast trending faults (Bergey et a l . , 1971)  (Fig. 9).  33  o  Generalized ore outline  Vertical Scale 0  IOO  ft  30m  FIGURE TO;  Horizontal Scale  0 0  I  ^ J^oou N  244m  Simplified geology across a section at Highmont (P=Quartz porphyry; S=Skeena granodiorite. See Fig. for l i n e of section)  34  Copper-molybdenum mineralization occurs within a l l rock types, north and south of the main dyke. (Fig. 9).  Principal  ore minerals are chalcopyrite, bornite and molybdenite. and specular!te are the other metallic minerals.  Pyrite  Ore minerals  occur as veins and fracture f i l l i n g s , within quartz and clay gangue (Bergey et a l . , 1971)*  Sulphide disseminations also occur within  altered host rock near fractures.  CHAPTER THREE WALL-ROCK ALTERATION  36  INTRODUCTION (a) General Statement Hydrothermal alteration and sulphide zoning i n wall rocks associated with ore deposits are closely-related products of oreforming and metasomatic processes. Guilbert, 1970).  (Rose, 1970; Lowell and  Because the formation of metasomatic minerals  generally Involves enrichment, depletion or redistribution of elements in wall rocks, an adequate understanding of their nature and distribution i s intrinsic to proper Interpretation and understanding of local epigenetic dispersion halos around orebodles. In porphyry copper environments, alteration zones are normally broader than the mineralization, and thus constitute larger targets for ore search, using mineralogical and chemical methods. (b) Methods of Study and Terminology Approximately 1500  samples collected from outcrops and  d r i l l cores f o r the purpose of geochemical analyses were utilized in mapping of alteration and sulphide distribution patterns. Emphasis was placed on large-scale patterns, as contrasted to alteration around individual veins (Rose, 1970).  Mineralogical,  textural and other megascopic physical properties of a l l samples were recorded i n the f i e l d , and approximately 200 of these were examined by X-ray diffraction.  X-ray analysis of fine-grained  clay minerals without the use of D.T.A. ( Differential Thermal  37  Analysis) or heat treatment facilities allows only an approximate identification.  However, this apparent drawback is compensated  by the large number of samples that can be analyzed per unit time. The terms, sericite, kaolinite and montmorillonite refer respectively, to the presence of a 1 0 A mica group mineral, a 7 A kaolinite group O  O  mineral and a 1 4 A montmorillonite-type mineral. 7 A kaolinite and 7A chlorite peaks were resolved by scanning at low speeds of 1o 0  29/min or less, using Cu K«£radiation, (12.3°29)  and chlorite at  7»08A  Kaolinite occurs at  (12.5°26),  7,16A*  Preliminary experiments  on quantitative determination of modal content using X-ray diffraction produced unsatisfactory results. This is attributed to the problem of preferred orientationjin layered silicates resulting in poor reproducibility (Bristol, 1968, 1972).  More than 1 0 0 thin sections  of fresh and altered rocks were examined for relationships between primary and secondary (alteration) minerals. Many d r i l l holes that were not sampled were also logged for their alteration mineralogy. The terminology presently used in the geologic literature for describing alteration minerals is in a state of flux (Fountain, 1 9 7 2 ) ,  To avoid confusion, the terms used in the following dis-  cussion are here defined on the basis of mineral assemblages (modified after Lowell and Gullbert, propylitic s  1 9 7 0 ;  Carson and Jambor,  1 9 7 4 ) ,  chlorite-epidote-calcite-albite-(adularia)  propyargillic:  chlorite-sericite-montmorillonite-epidote (kaolinite)  argillicj  kaolin!te-sericite-montmorillonite-(chlorite, quartz)  38  phyllic:  quartz-sericite-pyrite with less than %  kaolinite  or K-feldspar potassict  secondary K-feldspar-sericite-biotite (anhydrite, chlorite)  The term pervasive alteration i s used here only for alteration which i s evenly disseminated through,the rock and shows no apparent relationship to veins or fractures (Fountain, 1972). Vein alteration i s used here only for alteration which displays an obvious relation to veins or fractures.  Deuteric alteration effects  which are not directly related to hydrothermal processes are not described i n this presentation.  Northcote (1969) has shown that  deuteric alteration which involves minor chloritization of maf;ic minerals and saussuritization, i s widespread within the batholith. A l l alteration processes are considered as hypogene. Supergene alteration effects are either absent or negligible. BETHLEHEM-JA Guilbert and Lowell (1974) have briefly described the hydrothermal alteration patterns at Bethlehem-JA. They recognize three types of silicate alteration}  potassic  (K-feldspar-sericite-  phlogopite-biotite-chlorite), phyllic (quartz-sericite-chlorite) and propylitic (chlorite-epidote-carbonates).  McMillan (1973) mapped  potassic alteration at the centre of the property, coinciding with the porphyry dyke, and epidote-zeolite alteration at the periphery. In this study, two stages of alteration are recognized,  VO  FIGURE 11:  Generalized alteration map, Bethlehem-JA, 2800 Level  125m 4J)0ft  Argi11ic  /j  :.Intense P r o p y l i t i c  | j | Weak P r o p y l i t i c  |  | Potassic  |  j  Potassic FIGURE 12:  I (with c h l o r i t e )  II Generalized a l t e r a t i o n across a section of Bethlehem-JA (see Fig.11  for  line  of sectic  41  each stage comprising one or more types of alteration that are considered to be products of temporally related metasomatic processes.  The two stages are;  - an early main stage of pervasive  alteration associated with the major episode of Bethlehem-JA mineralization, and a later, lesser stage of zeolite alteration and epidote 0  veining. (a) Main Stage Pervasive Alteration Main stage alteration comprises three main types; potassic, a r g i l l i c and propylitic. Potassic Alteration i  Potassic alteration i s confined to the  porphyry dyke and adjacent rocks of the Bethlehem Phase (Figs.*, 11 and 12).  The characteristic mineral assemblage i s sericite-K-  feldspar-blotite.  At the outer margins of the potassic zone,  chlorite appears and gradually increases in abundance outward. The exact nature of K-feldspar - whether i t i s secondary or primary - i s not certain (K.G. McTaggart, oral comm.). Diagnostic textural evidence, such as complete replacement of plagioclase grains i s not apparent.  K-feldspar occurs mainly as inter-  s t i t i a l grains, similar to that of primary K-feldspar i n fresh Bethlehem rocks.  However, the following lines of evidence might  support a secondary origin for most of the K-feldspar (A. Soregaroli, oral communication).  F i r s t l y , the Bethlehem rocks i n the potassic  zone contain 20 - 26% K-feldspar (modal analysis of 4 samples) compared to a mean modal value of 10% and a range of 5 - 15% i n 1  42  fresh rocks (Northcote, 1969)• Secondly, K-feldspar occurs i n clusters, commonly forming rims around plagioclase but not obviously replacing them (Plate l ) .  Thirdly, the K-feldspar i s  domlnantly perthite or microcline compared with the dominant microperthite in fresh rocks (Westermann, 1970). Furthermore, twinning of K-feldspar i s common in the potassic zone but rare in fresh Bethlehem rocks (Westermann, 1970). Sericite occurs as fine-grained replacements of plagioclase feldspar and mafic minerals (Plate ••?'). Fine-grained, colourless to slightly pleochroic biotite (phlogopite) occurs as individual flakes within the groundmass.  It i s sparse and erratic in d i s t r i -  bution, generally constituting less than % of the rock.  Towards  the outer part and bottom of the zone (Fig. 12) chlorite occurs as a replacement of mafic minerals, and i n association with sericite and K-feldspar, constitutes5 - 1C$ of the rock. A r g i l l i c Alteration!  - This type of alteration, which occurs  within the northwest portion of the property, i s not concentrically arranged around the potassic zone (Fig. 11).  There i s a close  association between; ;zones of intense shearing within Bethlehem rocks and the distribution of a r g i l l i c alteration.  The characteristic  mineral assemblage i s sericite-kaolinite-montmorillonlte with minor chlorite, carbonate and epidote.  On the basis of this mineral  association, as determined by X-^ray diffraction, and the absence of abundant pyrite and secondary quartz, this zone i s considered a r g i l l i c and not phyllic as proposed by Guilbert and Lowell (1974).  43  Megascopically, in rocks of the argillic zone, plagioclose feldspars are chalky green and soft.  In thin section,  sericite is seen to be evenly distributed throughout the rock as a microscopic fine-grained replacement of feldspars. Fine-grained sheared quartz occurs as remnants. In zones of intense deformation, the original texture of the rock is destroyed. However, in zones of moderate argillic alteration, the crystal outline and twinning of plagioclase feldspars are discernible. Kaolinite occurs as very fine-grained dust in plagioclase feldspar. Montmorillonite and kaolinite were only positively identified by X-ray diffraction technique.  In the transitional zone between propylitic and argillic  zones, chlorite and epidote are associated with clay minerals. Propylitic Alterations  Propylitic alteration is most wide-  spread within the property, especially in rocks of the Guichon Phase. The propylitic zone is classified into two subzones on the basis of intensity of alteration (Fig. 11). The characteristic mineral assemblage is chlorite-epidote-carbonates-zeolite.  In the  intense propylitic zone, altered rocks are totally impregnated with coarse radiating chlorite sheaves ranging in size from 1-3 mm.  In  thin section, intensely altered rocks contain 40-80% chlorite which occurs as replacements of rock constituents and as inclusions within plagioclase feldspar (Plate 3). Epidote also replaces plagioclase grains• In weakly to moderately altered rocks, mafic minerals are partly or wholly replaced by chlorite, and plagioclase is dusted  44  with epidote and minor sericite.  Chlorite, epidote and carbonate  also occur as veinlets within this zone.  Quartz and alkali feld-  spars are apparently fresh. The propylitic zone grades outwards into either fresh rock or into rocks i n which regional deuteric alteration i s evident. (b) Late Stage Alteration Zeolitest  Within the JA deposit, zeolites occur abundantly as  veins, seams, and replacement minerals.  General distribution  patterns suggest no close spatial association between zeolite alteration effects and the main stage alteration and metallization processes.  Cross-cutting relationships suggest that zeolite formation  was probably post-mineralization, and of hydrothermal activity.  related to the waning stage  Such p r o l i f i c development of zeolites i s  commonly characteristic of hot spring activity. Although zeolites are ubiquitous within the property, they are most abundant towards the outer margins of the deposit (Fig, 13).  Minerals constituting the zeolite assemblage are leonhardite,  heulandite, s t i l b i t e and chabazite. Leonhardite i s the most common, and occurs as thick seams of pinkish-white soft material that ranges in width from less than 1 to 10 cm.  Commonly, i t i s pervasively  developed, replacing primary and secondary minerals.  Stilbite i s  next in abundance, and occurs as thin films ofjsalmon-pink colour, occupying fractures.  Chabazite rarely occurs as small, colourless,  euhedral crystals f i l l i n g vugs, and commonly associated with calcite and leonhardite.  These zeolites are seldom spatially associated  0  244m  "  .  (Geology, ofter  FIGURE 13:  D i s t r i b u t i o n of z e o l i t e a l t e r a t i o n at Bethlehem-JA  Bethlehem Mining  .  Stoff)  46  with sulphides, which further attests to their post-mineralization origin, Epidote»  Veins of very coarse epidote ranging in width from  1 - 10 cm generally cross-cut earlier alteration „ (Plate 4), which suggest post-mineralization emplacement (W.J. McMillan, pers, comm.). Sulphide Zoning Spatial distribution of metallic minerals i s shown in Fig. 14 and Fig, 15,  Generally, chalcopyrite i s the dominant  sulphide mineral within the orebody, with an average ratio of chalcopyrite to bornite  5*1  (Guilbert and Lowell, 1974)$ and even i n  the bornite zone, bornite rarely exceeds chalcopyrite.  The bornite  is centrally located and coincides with the relatively low grade porphyry dyke and potassic alteration, an association characteristic of many porphyry copper deposits (Lowell and Guilbert, 1970),  Quartz-  molybdenite veinlets are also wide-spread within this zone, (Fig, 14), The chalcopyrite zone, which i s the most extensive, i s characterized by chalcopyrite - pyrite - molybdenite, with sparse bornite.  This zone passes outwards into the pyrite zone in which  pyrite constitutes less than 2% of the mode. Vertical zoning i s generally defined by a decrease in chalcopyrite and increase in pyrite with depth (Fig.  15),  0  FIGURE 14:  244m  (Geology, after Bethlehem Mining  Generalized sulphide zoning at Bethlehem-JA, 2800 Level  Staff)  125 m 400f  t  FIGURE 15:  Generalized v e r t i c a l d i s t r i b u t i o n of sulphides Bethlehem-JA  at  49  VALLEY COPPER Hydrothermal alteration and sulphide distribution patterns at Valley Copper deposit have been well described by Allen and Richardson (1970), McMillan (1971, 1972), and briefly by Guilbert and Lowell (1974). Results of the present study confirm earlier findings, although a few modifications are suggested. Two main stages of alteration characterize the Valley Copper deposit - an early stage of pervasive a r g i l l i c alteration, on which a later stage of vein alteration has been superimposed. Vein alteration can also be classified into three substages, i n accordance with the sequence of emplacementj phase of barren  a relatively early  quartz and quartz-potash feldspar veining:  a main  phase of quartz-sericite and sericite veining, and a late phase of gypsum and relatively yoang quartz veining. Pervasive a r g i l l i c alteration i s associated with only minor disseminated mineralization, whereas quartz-sericite veining Is intimately associated with the ore-forming stage* (a) Pervasive A r g i l l i c Alteration Pervasive a r g i l l i c alteration occurs throughout and f o r a short distance beyond the ore-body (Fig. 16), and probably represents a product of "ground preparation" prior to the main stage of alteration and metallization.  Propylitic alteration i s  rare, probably due to the leucocratic nature of the host rocks. Intensity of a r g i l l i c alteration generally increases  FIGURE 16:  Generalized alteration map, Valley, Copper  3600 Level (Modified after McMillan,  1971)  51  from west to east and i s accompanied by a slight change i n mineralogy.  Where a r g i l l i c alteration i s weak to moderate, the  plagioclase feldspar i s white, relatively hard, and partially replaced by sericite, kaolinite and carbonate.  Microscopically,  sericite occurs as microcrystalline grains which rarely exceed 1mm  (Plate 5)»  feldspar.  Kaolinite occurs mainly*as 'dust* i n the plagioclase  As estimated from X- ray diffractograms, kaolinite con1  stitutes about  20-50$  of the mode. Quartz and potash feldspar are  commonly unaltered, whereas biotite i s replaced by sericite and mlnor:chlorite.  Where a r g i l l i c alteration i s intense, especially  in the eastern sector of the orebody adjacent to the Lornex Fault, Kaolinite content decreases to about 10 - 15$, and sericite i s relatively coarser.  The plagioclase feldspars are chalky i n various  shades of white and green and completely replaced by fine-aggregates of sericite, carbonate and kaolinite.  Primary K-feldspar and  biotite are i n many instances completely altered to sericite (Plate 6).  Quartz occurs as remnants, commonly containing numerous  fractures f i l l e d with sericite. Montmorillonite i s relatively uncommon, and has only been identified i n a few samples from the outer margins of the a r g i l l i c zone.  Minor albite persistently accompanies weak to moderate  a r g i l l i c alteration i n many samples. (b) Vein Alteration (i) Early Phase Veining The early phase of vein alteration at Valley Copper i s  52  characterized by a centrally-located stockwork of barren quartz veins and quartz veins with potash feldspar selvages. Barren Quartz Veinst  As shown i n Figure 16, these veins occupy  a low-grade stockwork zone in the southeast of the deposit. They consist predominantly of barren jrjoarse-grained quartz varying i n width from 1 mm to 5 cm, and commonly containing minute pods of sericite and/or K-feldspar. Quartz-Potash Feldspar Veins»  At the northeast part of the  barren quartz zone, K-feldspar envelopes around quartz veins are very common. The pink potash feldspar selvages range in width from less than 1 to 10 mm and pass outward into weakly argillized rock.  Like the quartz veins which they border, the potash feldspar  envelopes are generally barren, although a few contain chalcopyrite and minor molybdenite (McMillan, 1971). ( i i ) Main Phase Veining This phase of alteration i s characterized by quartzsericite and sericite veins formed during the main ore-forming stage.  Bornite and chalcopyrite occur predominantly as veins and  pods in association with quartz or as disseminated intergrowths with sericite. Quartz-Serlcite Veinst  Quartz-sericite and sericite veins occur  almost throughout the ore zone, but are developed most intensely in a zone nested upon the central quartz-rich zone (Fig. 1 6 ) , Quartz-sericite veins vary from quartz veins with coarse-grained  53  sericite envelopes varying i n width from 1mm  to 5 cm, to vuggy  quartz-sericite zones with hair-line or no apparent central quartz vein, to quartz veins containing only a few pods of sericite (McMillan,  1971).  These veins generally pass outwards into  argillized rocks or potash-feldspar selvages. Where many veins coalesce, pervasive sericite zones commonly develop, up to several metres wide. Microscopically, vein sericite relatively i s very coarse grained, usually forming rosettes 1 to 5 mm long and 0.5 wide of v e i n - f i l l i n g and replacement material (Plate 7).  to 3 mm Euhedral  to subhedral crystals of quartz which are commonly fractured and f i l l e d with fine-grained sericite, intergrow with very coarse sericite (Plate 8). Most of the sulphide minerals are intimately associated with the quartz-sericite veins. Minor secondary biotite accompanies sericite alteration. Potash Feldspar Alteration t  Potash feldspar generally occurs  as envelopes around quartz-sericite veins, passing outwards into argillized rock.  Locally the host rock i s flooded with pervasive  salmon-pink K-feldspar (McMillan,  1971).  Generalized distribution  of potash feldspar alteration i s shown i n Figure 16.  It i s strongly  developed along the western margins of the quartz-sericite zone, where i t also extends into the zone of pervasive a r g i l l i c alteration. In thin section, subhedral potash feldspar (mainly microcline) ranges l n size between 1 and 5 mm, and occurs as vein f i l l i n g or replacements of plagioclase and i n association with  54  coarsely c r y s t a l l i n e s e r i c i t e . The presence of K-feldspar envelopes around s e r i c i t e and i n equilibrium with k a o l i t e i s contrary to the s t a b i l i t y f i e l d relationships established f o r these minerals by Hemley and Jones :(4964). A s i m i l a r anomalous r e l a t i o n s h i p has been documented by Fournier (1967) at E l y , Nevada, and attributed to a resurgence of abnormally high s i l i c a a c t i v i t i e s of ore-forming f l u i d s . ( i i i ) Late Phase Veining Late phase veining comprises gypsum veins and young quartz veins which cut q u a r t z - s e r i c i t e veins.  relatively  The nature  and d i s t r i b u t i o n of gypsum veins are not c l e a r although they occur abundantly at depth, below the so-called 'gypsum l i n e ' 1971).  (McMillan,  They crosscut a l l the e a r l i e r veins and are associated with  minor anhydrite. (c) Sulphide  Zoning  McMillan (1971) has investigated the d i s t r i b u t i o n of chalcopyrite-bomite  r a t i o s within the Valley Copper deposit.  The generalized d i s t r i b u t i o n map  ( F i g . 16b)  shows that the low-grade,  quartz-rich core i s characterized by chalcopyrite - sparse bornite molydenite, passing outwards into bornite-chalcopyrite - low p y r i t e , and f i n a l l y to chalcopyrite - sparse bornite - minor pyrite at the outer part of the deposit.  P y r i t e , which generally constitutes  l e s s than 3$ of sulphide content within the orebody, forms a halo around the northern part of the deposit.  Minor hematite occurs  16b: Generalized  sulphide  (Modified  zoning, Valley Copper 3600 Level  after  McMillan, 1971)  56  throughout the orebody. LORNEX Wall-rock alteration patterns at Lornex are similar to those of Valley Copper except for the^extensive development of propylitic and propy-argillic assemblages, which are partly attributable to wall rock at Lornex (Skeena granodiorite) containing up to 15% mafic content;  a readily available source of Mg and  Fe needed f o r the formation of propylitic minerals. Also, the well-developed vein alteration effects at Valley Copper are only moderately developed at Lornex, although wide gouge zones with quartz-sericite alteration are prominent. Fipkie (1972) studied the alteration patterns i n samples across the orebody and his findings are generally consistent with the results of this study. Two stages of alteration are present at Lornex;  - an  early stage of well-developed pervasive a r g i l l i c and propylitic alteration, on which has been superimposed a main stage of intense, structurally controlled quartz-sericite alteration, gypsum veining.  K-feldspar and  Fig. 17 i s a generalized composite map of alter-  ation at Lornex, based upon observations i n the open-pit and studies of drill-core samples.  Generalized alteration patterns i n a section  across the orebody are presented i n Fig. 18, (a) Early Stage Pervasive Alteration Three main alteration zones characterize the early stage  POTASSIC HH  Ser.-  \  K-fsp-qtz.  Skeeno  ARGILLIC  r$=j^ Ser - kaol-qtz. PHYLLIC  Hi  Qtz-ser-(kaol.) PROPY-ARGILLIC  h-vW-J Ser-chl-montm. PROPYLITIC  ^3  Chi-ser-epid. Outer l i m i t of weak a l t e r a t i o n .  2000 ft 50,0 m  FIGURE 17:  Generalized a l t e r a t i o n map, Lornex 4900 Level.  Propylitic alteration Propy-Argillic alteration Argi11ic a l t e r a t i o n  o  v-  Approximate alteration boundary Quartz-sericite a l t e r a t i o n K - f e l s p a r - s e r i c i t e veining Gypsum veining  FIGURE 18:  400 ft 122m  Generalized a l t e r a t i o n , Lornex subsurface (see Fig. 8 for l i n e of^section and geology)  59  hydrothermal a c t i v i t y ;  p r o p y l i t i c , p r o p y - a r g i l l i c (mixed pro-  p y l i t i c and a r g i l l i c ) and a r g i l l i c .  Compared to early stage a l t e r -  a t i o n at Valley Copper, that of Lornex i s apparently associated with more sulphide mineralization, probably as a r e s u l t of numerous microfractures superimposed on the e a r l i e r phase of hydrothermal activity. P r o p y l i t i c Zonet  This zone occurs along the outer margins of  the orebody, generally extending from the  5°00  l e v e l s ) to the surface ( F i g . 17 and 18).  The dominant p r o p y l i t i c  l e v e l bench  (1972  mineral assemblage i s epidote^chloriteTcarbonate.- • Minor' s e r i c i t e , montmorillonite and z e o l i t e s are present within t h i s zone. In hand specimen, rocks of t h i s zone are various shades of green, as a r e s u l t of the high epidote and c h l o r i t e content.  In  zones of intense p r o p y l i t i c a l t e r a t i o n , epidote occurs as mediumgrained masses replacing plagioclase, (Plate 8 ) . and  b i o t i t e and hornblende grains  B i o t i t e i s generally altered to c h l o r i t e , leucoxene  quartz.  K-feldspar and quartz remain unaltered.  Further east,  away from the orebody ( F i g . 17), p r o p y l i t i c a l t e r a t i o n i s l e s s intense and plagioclase -feldspars remain r e l a t i v e l y fresh although preferential replacement of c a l c i c cores by fine-grained s e r i c i t e common.  L o c a l l y , carbonates  ( c a l c i t e , s i d e r i t e ) are  is  present.  P y r i t e , hematite and minor chalcopyrite are the predominant metallic minerals i n t h i s zone. P r o p y - A r g i l l i c Zone: This zone, which represents a t r a n s i t i o n between the  60  propylitic and a r g i l l i c zones, i s characterized "by significant increase in montmorillonite  and sericite and a general decrease in  epidote, although chlorite i s s t i l l widespread.  Plagioclase feld-  spar i s commonly replaced by sericite, montmorillonite  and allophane.  Mafic minerals are altered to sericite, chlorite and epidote.  Inter-  layered sericite-chlorite-montmorillonite i s locally present. Associated metallization represented by chalcopyrite and minor bornite i s low grade except where later fracture-filled mineralization is superimposed. A r g i l l i c Zonet  Pervasive a r g i l l i c alteration i s most widespread  within the orebody and coincides with the major zone of mineralization.. Intense fracturing and faulting within this zone have caused the development of extensive areas with quartz-sericite alteration; consequently i t i s often d i f f i c u l t to differentiate between a r g i l l i c and phyllic alteration within the orebody. South of the Lornex Pit (Fig. 1?) a r g i l l i c alteration i s well-developed within an area presently considered as protore (Discovery Zone;  Carr, 1967).  Megascopically, the argillized rocks are creamy-white and fragile, as a result of the pervasive fracturing and  shearing.  They are characterized by chalky-white to waxy green feldspars. The intensity of a r g i l l i c alteration progressively increases from the east to west, and this i s accompanied by progressive destruction of plagioclase, and lastly potash feldspar.  In areas of moderate to  weak a r g i l l i c alteration, the plagioclase feldspars are partly  61  altered to kaolinite, montmorillonite and waxy-green sericite (Plate 9).  Crystal outlines and twinning are generally preserved.  Mafic minerals breakdown into sericite, minor chlorite and leucoxene or quartz.  Wherever a r g i l l i c alteration i s intense, the  plagioclase feldspars are completely replaced by fine- to mediumgrained sericite, quartz and kaolinite with sericite the dominant mineral.  With increasing alteration intensity towards the west  near the Lornex Fault (Fig, 17 and Fig. 18), the a l k a l i feldspars also are completely altered to sericite and kaolinite. quartz with sericite i n fractures remain.  Only primary  Mafic minerals are also  converted to sericite, rutlie and leucoxene.  The metallic minerals  associated with argillized rocks are ore-grade bornite and chalcopyrite, as disseminates or fracture f i l l i n g s . (b) Main Stage Alteration The distribution of main stage alteration products i s controlled by structural features which probably developed after the early stage alteration processes.  Main stage alteration i s  classified into quartz-sericite and K-feldspar types. Quartz-Serlcite Alteration!  This type of alteration occurs as  envelopes around sulphide-bearing veins and within fault-gouge zones which range from less than 1 to 100 m i n width.  Distribution  of some of the zones with intense quartz-sericite alteration i s shown in Figures 17 and 18. These zones cross-cut earlier types of pervasive alteration, and show a dominant northerly trend coin-  62  ciding with the strike of faults and fractures.  Where quartz-  sericite alteration i s intense and extensive, primary textures of the rocks are completely destroyed.  A l l plagioclase feldspars  are converted to sericite, carbonate and quartz.  However,  kaolinite and minor chlorite may survive as r e l i c t s of the earlier pervasive alteration.  Commonly, a l k a l i feldspars are partially  or completed replaced by sericite and quartz. also are altered to sericite.  In DDH 8 (Fig. 18), muscovite;co-  exists with sericite and quartz. green t a l c . and sericite.  Mafic minerals  A few gouge zones contain dark  Pyrite i s a common sulphide i n association with quartz Ore-grade chalcopyrite and lesserijamount of bornite  predominatetwithin the ore-bearing veins and gouges. Potash feldspar Veiningt  Potash feldspar veins with a r g i l l i c or  quartz-sericite selvages occur abundantly i n two areas of the orebody;  one near the centre of the deposit within and" north of the  quartz porphyry dyke (Fig. 1?), and at depth adjacent to the Lornex Fault (Fig. 18).  In the latter the K-feldspar veins occur above  and within a (?) porphyry dyke (Fig. 8).  The veins and envelopes  consist of perthite and microcline within pervasively argillized rock.  Cross-cutting relationships suggest that the phase of K-  feldspar veining i s relatively younger than pervasive a r g i l l i c alteration. Gypsum Velnlngi  As at Valley Copper, the nature of gypsum  veining and i t s relationship to other forms of alteration i s not evident.  Figure 18 shows that i t i s generally encountered in deep  63  boreholes, cross cutting quartz-sericite and potassic alteration. Occurrence of anhydrite has not been reported. Sulphide Zoning Staff geologists at the Lornex Mine have established that a core, in which bornite exceeds chalcopyrite, i s enveloped by a zone i n which chalcopyrite exceeds bornite (Fig. 19).  A  pyrite halo, characterized by sparsely disseminated pyrite, coincides with the outer part of the deposit and zones of propylitic and propy-argillic alteration. SKEENA  A drill-hole that cuts through the Skeena quartz lode was examined for hydrothermal alteration patterns.  As shows i n  Figure 20, a r g i l l i c alteration increases i n intensity towards the lode.  The characteristic mineral assemblage i s sericite-kaolinite-  montrimollonite.  Potash feldspar i s relatively unaltered.  occurs at the outer fringes of the drill-hole.  Chlorite  The main sulphide  minerals are pyrite and chalcopyrite i n quartz-carbonate veins. HIGHMONT Compared to other major porphyry copper deposits l n the Highland Valley, the intensity of hydrothermal alteration at Highmont i s relatively weak, although alteration zoning i s moderately well-developed• Hydrothermal alteration affects are classified into two stages;  an early pervasive alteration ( a r g i l l i c and propylitic)  L  N  Bornite zone (Bn > 50%)  FIGURE 1.9.:  Sulphide d i s t r i b u t i o n at Lornex mine (After Lornex mining s t a f f )  66  and a later phase of vein alteration (K-feldspar and quartzsericite).  Tourmaline-biotite with minor sericite alteration i s  confined to breccia pipes and their immediate surroundings. (a) Pervasive Alteration Pervasive alteration effects are classified into propylitic, propy-argillic and a r g i l l i c types. Propylitic Alteration! Propylitic alteration i s confined mainly to the outer margins of the Nos. 1 and 2 ore zones and the areas surrounding the other small deposits south of the main dyke (Fig. 21).  Relatively weak propylitic alteration i s characterized by the  mineral assemblage chlorite-carbonate-epidote-zeolite.  Plagioclase  feldspars are generally fresh except for selective partial replacement of calcic cores by carbonate. and quartz (Plate 10).  Biotite i s altered to chlorite  Epidote occurs commonly as veinlets rather  than replacements of plagioclase feldspar. spars are relatively unaltered.  Quartz and a l k a l i feld-  Pyrite and lesser chalcopyrite are  disseminated within the altered rocks. Propy-Argillic Alterations  This type of alteration i s most  closely associated with sulphide mineralization.  The characteristic  mineral assemblage i s a sericite-chlorite-montmorillonite-carbonate. Veins of epidote, and albite replacements of plagioclase are also common within this zone. Figs. 21 and 22 show the distribution of propy-argillic alteration, north and south of the a r g i l l i c alteration zone.  It i s  FIGURE 2 1 :  Generalized alteration map, Highmont property.  69-108  ON CO  FIGURE 22  generalized.alteration map, Highmont subsurface? CSee  F i g 21 for line of section)  69  most prominent in the No. 2 Ore zone (Fig. 2 1 ) but also occurs in the small deposits in the south-western part of the property. Plagioclase feldspar in intensely altered rocks i s partly or completely replaced by sericite and carbonate, preserving only the crystal outlines.  Calcite occurs as replacement of primary  minerals, and as veinlets. Mafic minerals (generally) are replaced by sericite, leucoxene and chlorite. Alkali feldspars are commonly dusted with sericite, whereas quartz remains fresh.  Epidote replaces  plagioclase feldspar and hornblende, but i s most common as veins. The principal sulphide mineral i s chalcopyrite with minor bornite and disseminated pyrite. A r g i l l i c Alterationi  The a r g i l l i c zone i s centred upon the  quartz porphyry dyke (Figs. 2 1 and 2 2 ) , forming an annulus around zones with potassic, tourmaline and quartz-sericite alteration. This distribution pattern reflects the influence of wall-rock composition upon alteration type.  The characteristic mineral  assemblage i s kaolinite-montmorillonite-serlclte-(carbonate). Where a r g i l l i c alteration i s well-developed, the plagioclase feldspars are completely replaced by fine-grained kaolinite, sericite and minor montmorillonite (Plate 1 1 ) .  Carbonate occurs as replace-  ment patches and veins within plagioclase feldspar.  Under con-  ditions of weak to moderate a r g i l l i c alteration, alternate crystal zones within plagioclase feldspar are selectively replaced by kaol i n i t e , thus accentuating the crystal zoning.  Alkali feldspars  generally remain fresh although commonly they are dusted with  70  sericite and kaolinite.  Mafic minerals break down to sericite  and leucoxene. (b) Vein Alteration Quartz-Sericite Alteration} Quartz-sulphide veins with potash feldspar envelopes are common within the zone of a r g i l l i c alteration, i n association with the main porphyry dyke (Fig. 22). Figure 21 shows a small potassic zone within the porphyry dyke and southeast of the No, 1 ore zone, In which extensive, K-feldspar/ aplite veining locally grade into pervasive alteration.  Tourmaline  also occurs i n association with some of the quartz-potash feldspar veins which often contain chalcopyrite. Quartz-Tourmaline-Biotite Alteration!  Tourmaline (schorl) i s  associated with breccia pipes and surrounding rocks. The breccia zones are spatially and genetically related to the quartz porphyry dyke (Carr, 1966).  Tourmaline occurs as elongated and radiating  crystals cementing the breccia fragments and as disseminations within the surrounding porphyry (Plate 12).  The breccias are also  s i l i c i f i e d as a result of the introduction of anhedral secondary quartz into the matrix. with sericite.  Plagioclase feldspars are commonly dusted  Sparse, fine-grained secondary biotite i s associated  with tourmaline impregnation.  Quartz-sulphide veins also contain  disseminated tourmaline. Gypsum Veining;  Gypsum veins have been encountered i n a few*  drill-holes, especially Hole 69-108, although the nature of their  71  distribution and relationship to other forms of alteration are not clear.  They are generally associated with zones of intense  a r g i l l i c alteration. Sulphide Zoning Zonal distribution of metallic sulphides i s summarized in Figure 23 • The data were obtained mainly from company f i l e s . In the two major ore bodies mineral zoning i s parallel to the dyke. East of the No. 1 ore zone and immediately north of the dyke, the author observed that the predominant sulphide i s chalcopyrite, and thus a chalcopyrite zone i s suggested (Fig. 23a).  Generally, i n a zone  north of and parallel to the dyke bornite and chalcopyrite occur i n roughly equal amounts;  this zone grades outwards to one of chal-  copyrite, sparse pyrite and rare bornite, and f i n a l l y to a pyritic zone in which pyrite locally amounts to 1 percent of the rock (Bergey et a l . , 1971),  The MoS zone i s slightly displaced south of the Cu 2  zone in Nos. 1 and 2 ore zones (Fig. 23b). FACTORS CONTROLLING WALL-ROCK ALTERATION Host rock composition, structural features and chemistry of mineralizing solutions influence the nature and intensity of wall-rock alteration i n Highland Valley. (a) Host Rock Composition The effects of host rock lithology on alteration are apparent i n a l l the Highland Valley deposits. Propylitic alteration  800ft 9  ?44m  Higher-grade Copper JN^  Ore-grade Copper  _/*  Mineral zone boundary Ultimate p i t boundary FIGURE 23a:  Mineral zoning and copper grade at Highmont property (Data from company f i l e s , Highmont Mining Corporation)  Ore-grade M0S2 Higher-grade M0S2 Mineral zone boundary Ultimate p i t boundary FIGURE 23b:  D i s t r i b u t i o n of M0S2 in r e l a t i o n to mineral zoning at Highmont (Data from company f i l e s , Highmont Mining Corporation)  74  i s rare at Valley Copper partly because of the more leucocratic composition of the host rock (Bethsaida granodiorite).  A similar  reasoning applies to the r a r i t y of propylitic alteration within porphyry dykes at Highmont and Lornex.  In these leucocratic rocks  adequate Mg and Fe were not available for formation of abundant chlorite.  Hence, s e r i c i t e , kaolinite and carbonate are the  dominant alteration products.  Hydrothermal addition of K  +  and  SiOg, probably from deep-seated sources led to extensive development of quartz, s e r i c i t e and K-feldspar, At Bethlehem-JA, potassic alteration i s associated with the f e l s i c porphyry and adjacent Bethlehem Phase. In contrast, propylitic alteration i s most intense i n the more mafic rocks of the Guichon Phase. A r g i l l i c alteration i s best developed i n leucocratic Bethsaida rocks immediately east of the Lornex Fault at Lornex mine and within the main porphyry dyke at Highmont, In contrast, rocks of the Skeena phase are commonly associated with prop y l i t i c and propy-argillic alteration. (b) Intensity of Faulting and Fracturing Wherever intense faulting and fracturing are developed, the general tendency i s towards quartz-sericite alteration and  75  veining.  This relationship i s reflected in a l l the deposits.  At Valley Copper, zones with intense fracturing and crackle brecciation are flooded with quartz-sericite veins.  Gouge zones  at Lornex and Highmont are commonly characterized by quartz-sericite alteration.  At Bethlehem-JA, a r g i l l i c alteration is closely  associated with zones of intense shearing. From the foregoing, i t i s apparent that zones of structural weakness permit an easy infiltration of hydrothermal solutions. Consequently, development of extensive hydrolitic base leaching i s associated with formation of sericite, kaolinite and quartz.  These  also are the most preferred sites for ore deposition. (c) Composition of Mineralizing Solutions Chemical and physical properties of ore-forming fluids influence alteration patterns.  As mineralizing fluids migrate from  centres of mineralization, they cool and react with wall rocks. These processes culminate in changes i n pH, Eh, sulfur fugacity, temperature and pressure of the solutions.  These changes partly  account for the zoning and decreasing intensity of alteration from the centre to periphery of the deposits.  At Valley Copper, where  there is only one type of host rock, alteration patterns: grade Inwards from weak to moderate a r g i l l i c at the outer margins, to intense phyllic and potassic alteration at the core.  At Lornex,  and Highmont, weak propylitic alteration at the periphery grades inwards into propy-argillic and f i n a l l y into a r g i l l i c alteration.  76  (d) Structural Levels of Ore Formation Although the porphyry copper deposits of the Highland Valley are generally considered as products of relatively deepseated hydrothermal processes (Guilbert and Lowell, 197^; Brown, 1969),  W.J. McMillan (oral communication) has suggested that the  deposits were formed at different structural levels.  For example,  the Highmont and Jersey deposits which are spatially associated with "breccia pipes (Carr, 1 9 6 6 ) are considered to have formed at structurally higher levels in the crust than neighbouring deposits. The deposits can be arranged ln the following sequence, from those formed at relatively deep to shallow structural levels; Copper, Lornex, Bethlehem-JA, Highmont and Jersey.  Valley  This sequence  corresponds roughly with decreasing intensity of wall-rock alteration, ore size and grade. Carr  (1966)  suggested that the breccia zones at the Jersey  and Highmont deposits were formed when volatile pressures exceeded lithostatic pressure, culminating in the escape of volatiles.  Thus,  the relatively weak alteration and ore size of these deposits might partly be attributed to the inability of volatile solutions to react intensely with host rocks.  In contrast, ore deposits formed  at deeper structural levels show evidence of intensive and extensive reaction of volatile solutions with wall rocks.  From the foregoing  discussion, i t i s apparent that variations i n wallfyrock alteration can be partly attributed to the nature of ore emplacement, which might consequently influence the nature and extent of geochemical  77  halos associated with these deposits. SUMMARY AND CONCLUSIONS (1) Except at Valley Copper where propylitic alteration i s rare, mineral deposits of the Highland Valley are characterized by zonal distribution of alteration patterns}  propylitic at the  periphery, grading inwards into pervasive a r g i l l i c and/or phyllic alteration.  Potassic alteration i s generally centrally located,  in association with porphyry dykes.  Structural features dominantly  control the distribution;<of quartz-sericite alteration, (2) Except at Jersey deposit (White et a l . , 1957),  biotite i s  not an important mineral in potassic zones of Highland Valley porphyry/ copper'deposits, (3) Economic mineralization i s most commonly associated with zones of intense a r g i l l i c (or propy-argillic) and quartz-sericite alteration, whereas potassic and propylitic zones are relatively devoid of mineralization. (4) Intensity of wall-rock alteration correlates with- grade and size of mineralization. (5) Although the inability to quantify alteration patterns, and the fine-grained mineralogy characteristic of alteration zones are major limitations, large-scale mapping of wall-rock alteration can be useful ln delineating zones most suitable for detailed exploration.  PLATE 1: Conglomeration of (?) secondary perthitic K-feldspar i n Bethlehem quartz d i o r i t e of the potassic zone, Bethlehem-JA, PLATE 2: Sericite alteration of plagioclase and a l k a l i feldspars i n potassic zone of Bethlehem-JA.  (s = s e r i c i t e )  PLATE 3s Course-grained sheaves of interlocking chlorite i n the propylitic zone of Bethlehem-JA. PLATE k: Medium- to coarse-grained cryste3sof epidote ( v e i n - f i l l i n g materal) i n the propylitic zone of Bethlehem-JA. PLATE 5: Pervasive s e r i c i t e ( + minor kaolinite) and quartz remnants i n the a r g i l l i c zone of Valley Copper deposit. PLATE 6: Alteration of coarse b i o t i t e grains to fibrous s e r i c i t e i n the a r g i l l i c zone of Valley Copper deposit.  ( A l l plates crossed nicols)  78  b  PLATE 7 s Very coarse-grained  s e r i c i t e (vein material) i n the  phyllic zone of Valley Copper deposit. PLATE 8:  Fine-grained epidote p a r t i a l l y replacing a b i o t i t e grain i n propylitized rock of Lornex mine.  PLATE 9 ' Fine to medium-grained s e r i c i t e and kaolinite i n the a r g i l l i c zone of Lornex mine. PLATE 10: Quartz and chlorite replacements of a b i o t i t e grain i n the propylitic zone of Highmont deposit. PLATE 11:  Weak a r g i l l i z a t i o n of plagioclase (with minor carbonate) at Highmont property.  PLATE 12: Radiating tourmaline crystals (schort) i n a breccia matrix at Highmont.  ( A l l plates crossed nicols)  79 b  'CHAPTER FOUR SAMPLING AND ANALYTICAL TECHNIQUES  81  SAMPLE COLLECTION During May to August 1972 and June 1973» approximately 1800 bedrock samples (excluding duplicates) were collected from the Highland Valley d i s t r i c t .  Table III summarizes the number and  nature of samples. (a) Outcrop Sampling Sampling of outcrops was undertaken at Highmont, Lornex, Skeena and Bethlehem properties. in the Appendix.  Sample locations are presented  Outcrops at Highmont, although not abundant, are  uniformly distributed, and samples were collected from most of them. At Lornex, outcrops are plentiful and relatively fresh, west of Lornex Fault, whereas to the east, open-pit development, construction and dumps have obliterated many. Thus, the topmost part of d r i l l cores (suboutcrops) were used to supplement outcrop samples. A l l samples comprise k to 5 g of half fist-sized rock K  2 chips collected over a surface area of about 10m .  Weathered  surfaces were removed, and fresh chips placed i n heavy-duty plastic bags.  Most of the outcrop samples were collected beyond zones of  visible mineralization and were apparently unaltered.  Subsequent  thin section examination however, reveals that sericite "dusting. " of plagioclase i s widespread. This can be attributed to regional deuteric alteration that i s ubiquitous i n rocks of the batholith (Northcote, 1969). For comparison, limonite-rich samples (oxidized  82  TABLE III:  . Summary-of sampling and chemical analysis.  Property  Type of Sample  Highmont  Ko, of Samples  Analytical techniques*  Outcrop Fresh rock Limonite-rich rock  Lornex  Skeena  AAT, ES, AAM  192  AAT.ES  28  D r i l l Core  550  TOTAL  760  Outcrop  90  AAT, ES, AAM  D r i l l Core  425  AAT, ES, AAM  TOTAL  "515"  XRFT, AAM, AAT, FAA, ES  Outcrop  20  AAT, ES, AAM  D r i l l Core  40  AAT, ES, AAM  TOTAL  ~60~  Suboutcrop  58  2800 Level  • 5^  2400 Level  48  Bethlehem (JA Zone)  (Others)  Valley Copper  AAT, AAM, FAA, XRFM, XRFT, ISE AAT, ES  Outcrop  106  AAT, AAM, E3  D r i l l Core  120  AAT, AAM, ES  TOTAL  386  Suboutcrop  61  AAT, ES  3600 Level  59  AAT, AAM, FAA, XRFM, XRFT, ISS  3300 Level  41  AAT, ES  TOTAL  * XRFT XRFM AAT AAM FAA ES ISE -  AAT, ES  161  X-ray fluorescence - Rb, Sr, S, Zr X-ray fluorescence - SiO„, P 0,, Al-C.,, T i 0 Atomic absorption - Cu, Zn, Jap, Ag, NI, Co, Pb, Cd Atomic absorption - MgO, CaO, FegO-, KgO Flameless atomic absorption - Hg Emission spectropgraphy - B, V, Sr, Mo, T i , 3a, Sr, Ga Ion-selective electrodes - Cl, F ?  2  83  zone) were collected from several localities along with fresh bedrock at Highmont.  In more than 20 localities, duplicate samples  were collected f o r evaluating sampling error (Garrett, 1969). (b) Drill-Gore Sampling Drill-core chip samples were collected at intervals of 3m (10ft) i n sections across Highmont, Valley Copper, Lornex, Skeena and Bethlehem properties.  Each sample comprises several 5 cm long  chips collected over a distance of 3m around the sampling point. No discrimination was made between fresh and altered samples. Valley Copper and Bethlehem-JA are buried almost completely beneath glacial and a l l u v i a l overburden. A modified sampling pattern, in which samples were collected from several evenly-spaced d r i l l holes at constant elevations or "levels", was employed. each deposit three levels were sampled}  In  a "Suboutcrop Level" which  represents the topmost part of d r i l l holes beneath the oxidation zone, and two other levels, each designated by i t s elevation above sea  level.  Duplicate samples were collected i n approximately k0/  0  of the drill-holes, using sample locations 3m above the original sampling point.  At Valley Copper and Bethlehem-JA, samples were  obtained within and as f a r from the orebody as available d r i l l holes permit.  It i s believed that the number of drill-holes i n background  areas i s adequate f o r purposes of this study. Megascopic features of a l l samples were recorded i n the f i e l d , including rock type, mineralogy, alteration, visible mineralization and fracturing.  Locations of drill-core samples at the  84  various mining properties are presented i n the Appendix. SAMPLE PREPARATION (a) Crushing and Grinding Chip samples were fed into a Bico "Chipmunk" jaw crusher. Crushed material was then pulverized to less than 2mm  in a ceramic  rotary grinder. After splitting, approximately 50g were further ground to minus 100 mesh i n a high speed ceramic ball mill.  To  estimate sample homogeneity, replicates of the fine rock powder were obtained by grinding separately three additional splits of every f i f t i e t h pulverized sample.  Material remaining from the  ceramic grinder was reserved for mineral separation studies. A piece of every rock sample was also preserved f o r reference. (b) Mineral Separation Mineral separation was performed on the minus 35 plus 120 mesh fractions of samples obtained by sieving the pulverized material from the ceramic grinder. Each sample weighed approximately  1kg,  Samples were washed by transfering portions into large beakers f i l l e d with tap water, and stirred thoroughly with a rubber-tipped heavy glass rod.  The material was allowed to settle for a minute  and the supernatant liquid decanted. dozen times.  This operation was repeated a  Samples were then washed with d i s t i l l e d water and  dried i n an oven at 110°C. Magnetite, iron f i l l i n g s and other mineral grains with magnetite inclusions were removed with a hand magnet before passing the material through a Frantz isodynamic  85  separator using a forward slope of 20° and side slope of 15°. In this way i t was possible to obtain a preliminary separation of biotite and hornblende from quartz and feldspar. Additional purification was achieved using heavy liquids bromoform or tetrabromoethane (S.G.=2.9) and methylene iodide (S.G.=3,3). A conical 500-1000 ml separating funnel was halff i l l e d with bromoform, and small portions of samples were carefully added through a f i l t r a t i o n funnel.  The liquid was swirled within  the separatory funnel from time to time for about an hour in order to obtain complete separation of light and heavy fractions. The heavy fraction was then released and filtered through a No, 1 or 41 Whatman f i l t e r paper.  Mineral fractions were washed with acetone  and dried in a i r or under a lamp, Biotite was separated from hornblende using methylene iodide in a smaller 5°-100 ml separating funnel.  However, hornblende  content of most samples was small, and adequate separates were obtained only from two samples. Better than 95% purity was attained by handpicking remaining impurities, such as zircon and apatite, under a binocular microscope. ANALYTICAL TECHNIQUES Rock samples were analyzed by emission  spectrography,  X-ray fluorescence spectrometry, flame and flameless atomic absorption spectrophotometry and ion-selective electrodes. Elements determined by the above procedures are summarized in Table III. Routinely, a blank, a sample of UBC standard rock, and a duplicate  86  were included i n every batch of 2k analyzed samples. (a) Emission Spectrography Semi-quantitative procedures for spectrographic analysis are described by Doyle  (1972)  and Hoffman  (1972).  A powdered rock  sample, mixed l s l with graphite containing 100 p.p.m. indium as internal standard, was loaded into a graphite cup electrode, sealed with sugar solution, and excited by a 12 ampere DC arc for 20 seconds. Spectra were recorded on spectrographic plates and element concentrations estimated visually by comparison with master plates of known concentration. Operating conditions are summarized i n Table IV, after Doyle  (1972).  Analytical precision estimated from replicate  analysis of UBC standard rock (Stanton, 1966)  i s presented i n Table V.  (b) X-Ray Fluorescence Spectrometry Major Elements! 1.5g  0.28g powdered sample was mixed thoroughly with  flux containing lithium tetraborate, lithium carbonate and  lanthanum oxide (Norrish and Hutton,  1969).  The mixture was fused  for approximately 20 minutes in a graphite crucible at  1150°C and  the  melt then rapidly poured onto an aluminum-coated plate where i t solidified to give a glass bead. The bead was pulverized i n a Spex ball mill f o r 15 minutes, the powder bound with a few drops of polyvinal alcohol (FVA), and then compressed into a pellet, backed by a mixture of l s l boric acid and bakelite. 20,000 lbs was used i n pellet compaction. a pellet approximately 3cm  A load of  The resulting sample i s  i n diameter and 5 mm thick.  87  TABLE IVi  Spectrographic equipment and standard operating c o n d i t i o n s .  Spectrograph  Hilga-Watts Automatic Quartz Spectrograph  Source  E l e c t r o m a t i c products (ARL), Model P6KS, Type 2R4?  Arc/Spark stand  Spex Industries #9010  Microdensitometer  ARL S p e c t r o l i n e Scanner #2200  Anode  Graphite, National L 3 7 0 9 S P K  Cathode  Graphite, National L38O3AGKS  3-step n e u t r a l f i l t e r  Spex Industries #1090; mittance  %,  Neutral  Spex Industries #9022;  20jb transmittance  filter  Emulsion  Spectrum a n a l y s i s #1  Wavelength range  2775 to 4800 angstroms  Kask  17  Slit  width  mm  15 microns  Arc current  1 2 amperes  Arc gap  ;  Exposure  time  6mm  30seconds  Plate processing  Developer Kodak D-19 at 23°C  Plate processing  Stopbath Kodak 30 seconds  Plate processing  F i x e r Kodak 5 minutes  Plate processing  "5 minutes  2QS and 100/S t r a n s -  88  TABLE V:  Spectral lines and *precision at the 95% confidence level of emission spectrographic analysis (24 analyses of UBC standard rock)  Element  Spectral Lines (Angstroms)  Mean Value (ppm)  Precision - %  B  2497.73  n.d  -  Sr  4607.33  711  42  Ti  3372.80  1281  66  V  3185.40  36  Mo  3170.35  n.d  Ba  4554.04  590  39  Ga  2943.64  18  33  Sn  2839.90  n.d  n.d = below detection l i m i t *  After Stanton (1966)  -  -  89  Minor Elements!  3g of minus 100 mesh powder was "bound with a  few drops of PVA, and then pelletized, using the procedures >  described earlier. Analytical determinations were made using a Philips PW 1010 spectrometer. VI.  Operating conditions are summarized i n Table  Calibration curves were obtained from U.S.G.S. standard rocks  G-2, GSP-1, AGV-1, BCR-1 and W-l.  Recommended values for these  standards were obtained from Flanagan (1973)• Analytical precision for major elements i s better than - 8$ at the 95% confidence level. For Rb, Sr and S, precision at the 95$ confidence level i s - 2$, - 1$ and - 15$ respectively, based on data from 18 paired samples (Garrett, 1969). (c) Ion-Selective Electrodes Total Extractable Halogens!  The analytical procedure i s slightly  modified from that of Haynes and Clark (1972). with l g 2si sodium carbonate—potassium crucible;  0.25g sample was mixed  .nitrate in a 40 ml nickel  fused at 900°C f o r 20 min and then cooled f o r 10 min.  20 ml of boiling water were added, and the crucible covered and l e f t overnight.  Contents of the crucible were stirred to detatch the  adhering cake, and then washed into a 100 ml volumetric flask.  Pre-  liminary experiments indicated that there was no difference between results obtained from filtered and unfiltered solutions,  Unfiltered  sample solutions were therefore diluted to 100 ml with de-ionized water after addition of 1,5 ml concentrated n i t r i c acid.  TABLE VIi  Element S10  .  2  A1 0 2  3  2°5  P  Meo CaO  Operating  X-Ray Tube.. Target kV  c o n d i t i o n s f o r P h i l i p s PW 1010 X-ray spechometer  mA  Peak (20)  -  20  EDDT  -•  10  . -  20  Cr  50  30  112.7  ZT  50  30  58.8  Sr  50  30  20.36  -  10  Cr  50  30  14.50  -  100  40  20  -  10  78.11  113.3  CT  40  20  Cr  40  20  57.49  Hb  W >  50  30  26.53  3r  Mo  50  30  25.09  S  Cr  44  30  45.20  50  30  22.51  Zr  CTff.  30 • '  cr  3  XTAL  50  Fe 0 2  F.T. ( s e c ;  Cr  T10  2  1<-G (20)  •ff  86.14  Explanation o f Abbreviations. B-G - Background p o s i t i o n F.T - F i x e d Counting -Time flTA:. - A n a l y z i n g C r y s t a l EDDT- Eth;, lene-Diamine-d-Tartrat.-! U P - Lit:-iur. F l u o r i d e HA? - Rubidium A c i d Ph'.lialate CTR - C o v t e r (X-ray d e t e c t o r )  CTRY(KV)  X-RP  F.P.  4.64  Vac.  EDDT  F.P.  4.64  EDDT  F.P,  EDDT  PHW  Atten.  200  450  2  Coarse  Vac.  180  300  2  Coarse  ^.55 '  Vac.  250  300  2  Coarse  F.P.  4.55  Vac.  200  450  2  RAP  F.P.  4.85  Vac.  250  400  2  Coarse  LIF  F.P.  Vac.  150  500  2  Fine  4.25  Vac.  180  . ' ^-35  i'HLV  ' Collim.  F i n e •'  -  10  LI?  F.P.  300  2  Fine  -  10  LIF  F.P.  4.25 .  Vac.  300  350  2  Fine  40  LIF  Soint.  2.675  Air  270  400  5  Fine  40  LIF  Solnt.  2.675  Air  270  . 400  5  Fine  40  EDDT  F.P.  4.60  Vac.  100  200  3  Coarse  10  LIF  Scint.  2.675  Air  250  600  •5  Coarse  25.90 - 44.20 -  F.P - Flow P r o p o r t i o n a l Counter S c i n t . - S c i n t i l l a t i o n Counter CTRV - Counter Voltage X-RP - X-ray Fath Vac. Vacuum ?KLV - Pulse Height i e v s l Voltage PHW - Pulse Height '..'irdow Atten. - Attenuation Collim - Collimator  o CD  90b  TABLE VII:. Equipment and stock reagents in ion-selective' electrode analysis  Equipment Orion 407 meter or equivalent Orion 94-17 chloride electrode or equivalent Orion 94-02 double junction reference electrode Orion 94-09 fluoride electrode Orion sleeve-type reference electrode (for F) Orion 90-00-01, 90-00-02, 90-00-03 reference electrode f i l l i n g solutions 40 ml capacity nickel crucibles and lids Magnetic s t i r r e r and teflon s t i r r i n g rods  Stock Reagents Fluoride buffer solution:  dissolve 59g sodium citrate dehydrate and 20g  potassium nitrate in water and dilute to 1 l i t e r . Fluoride standard (lOOOHg/ml): dissolve 1. 105g sodium fluoride in water and dilute to 500 ml. Chloride standard (10,000 Hg/ml):  dissolve 16.48  g sodium chloride i n  water and dilute to 500 ml. Flux:  thoroughly mix 2:1 sodium carbonate*potassium nitrate  91 In determination of fluorine, 10 ml sodium citrate were added to an equal volume of sample solution i n a 50 nil plastic beaker.  The solution was stirred for 5 min with a small magnetic  s t i r r e r at medium speed, fluoride and reference electrodes inserted, and a millivolt (mV) reading (expanded scale) was taken with an Orion 407 meter.  The millivolt reading was compared to similar  readings from a series of standards containing appropriate concentrations of fluorine (0,1, 0,5 and 1,0 p.p.m.) i n a similar sodium citrate matrix (Haynes and Clark, 1972). For determination of chlorine, chloride and reference electrodes were inserted i n the same sample solution, and readings obtained using the "known addition" method (Orion Research, 1970). Operating conditions, equipment, and reagents are summarized i n Table VII*  Results obtained by these procedures for U.S.G.S. standard  rocks GSP-1 and AGV-1 are compared with recommended values (Flanagan, 1973) in Table VIII. Water-Extractable Halogenst  The analytical procedure i s des-  cribed in detail by Van Loon et a l . (1973)• l g sample was weighed into a 50 ml plastic beaker, and 5 ml de-ionized water added. The solution was stirred for 2-3 min, the electrodes inserted and a millivolt reading taken after allowing a response time-interval of an additional 20 sec.  Millivolt readings were compared to similar  readings from a series of standards. (d) Atomic Absorption Spectrophotometry Techtron AA-4 and Perkin Elmer 303 spectrophotometers were  92  TABLE V I I I :  Comparison o f f l u o r i n e and c h l o r i n e c o n t e n t s o f U.S.G.S. standard rocks.  This  Sample No.  F (p.p.m.)  GSP-1  AGV-1  Study  Recommended V a l u e s *  C l (p.p.m.)  3000  384  2860  384  3260  312  2900  320  660  272  580  269  600  258  * A f t e r Flanagan  (1973)  F  (p.p.m.)  Cl  (p.p.m.  3200  300  435  110  93  utilized i n major and trace element determinations, except for Hg which was determined by a flameless procedure on a Jarrell-Ash 82-270. Operating conditions f o r the three instruments are summarized i n Tables IX, X and XI. HF - HClOjj - HNO^ Digestion:  Total decomposition was accomplished  in two ways: a rapid "teflon tube" and a routine "teflon dish" procedure.  In the former, working solutions were prepared by  decomposing O.lg of minus 100 mesh powder i n 1 ml hydrofluoric acid and 1 ml nitric-perchloric acid mixture using teflon test tubes.  Acid  -  digestions were evaporated to dryness at 200°C on a sandbath and residues redissolved i n 1 ml hydrochloric acid.  Sample solutions  were made up to 10 ml with 1.5M HC1 and analyzed f o r Cu and Zn. 1 ml was diluted to 10 ml with d i s t i l l e d water and analyzed f o r Ca, K,  v  Na and Fe, To suppress molecular and ionization interferences, lanthanum and cesium solutions were added to both sample solutions and standards.  Analytical precision at the 95$ confidence level i s  summarized in Table XII.  In the routine "teflon dish" procedure, 0.5g samples were taken to dryness with 10 ml hydrofluoric acid and 5 ml 3*2 n i t r i c : perchloric acid mixture i n teflon dishes.  Residues were leached with  5 ml 6M hydrochloric acid and made up to volume i n a 25 ml volumetric flask.  As shown i n Table XII, analytical precision i s better than  that obtained with the rapid procedure.  Accuracy of the total  digestion i s evaluated by duplicate analysis of U.S.G.S. standard rocks (Table XIII).  v  TABLE IX: Operating conditions f o r techtron AA-4 spectrophotometer  Element  Current (mA)  Wavelength (A)  S l i t width (A)  Cu  3  3247.5  1.7  Zn  6  2138.6  3.3  Fe  5  3719.9  0.8  Mn  10  2794.8  3.3  Mg  4  2852.I  1.7  Na  5  5890.0  3.3  Ca  10  4226.7  0.8  K  10  5889.9  6.6  /Flame height 2.3 (arbitrary units) Acetylene flow gauge 2.5 (arbitrary units) A i r pressure 20 p . s . i .  TABLE X:  Operating conditions f o r the Perkin Elmer 303 spectrophotometer  4  1  1"  1  10  1 •  1  1  2  2  2  2  1  1  1  1  20  20  15  :-5  5  20  20  20  2324  2407  3719  328O  3853  2125  2956  VIS  VIS  1  2  2  2  "14  14  5  Scale  1  2  Damping  2 14  2175  2146 •  Ni  20  UV  UV  UV  uv.  UV  -  +  -  +  +  -  —  _  _  _  -  • -  Range  UV  H Lamp Filter  0  4  1.  4  Wavelength (A) 3248  4  1'  4  Current (mA)  4  3  Slit  .Na  3  3  Zn  Ca  Cd  Fe  Pb  Ag  Mn  Co  Cu  2800  2283  UV  UV  uv  VIS  -  +  +  -  -  +  -  4  3  -  -  - Not required + Required Flame height 2.3 (arbitrary units) rain a i r pressure 3° p . s . i . Auxiliary a i r pressure 4 p . s . i . Acetylene pressure 4 flow units Meter response 2  96  #TABLE XIs  O p e r a t i n g c o n d i t i o n s f o r t h e J a r r e l l - A s h 82-270 s p e c t r o p h o t o m e t e r .  Hg D e t e r m i n a t i o n  Lamp c u r r e n t  5  Gain  3  Mode  Absorbance  Scale expansion  300  Damping  2  Wavelength (A)  2550.0  Cell  mA  dimensions length  21  diameter  3  cm cm  Slit  15 V  C h a r t speed  2 inches/minute  M a i n o s t a t Pump speed  5  1  97  TABLE XII:  *Analytical precision of  HF/HGIO^/HNO^  digestion at the 95%  confidence l e v e l estimated from paired samples.  Element  Teflon tube procedure Precision ( + %) 70 samples  Teflon dish procedure Precision ( + %) 10 samples 8  Cu  20  Zn  15  Fe  21  10  Ca  18  2  Na 0 2  9  2  KjO  19  3  MgO  -  1  (-) Data not available  * After Garrett (1969)  98  TABLE XIII:  Comparison of trace and major element contents of U.S.G.S, standard rocks. Recommended Values  G-2  GSP-1  This Study (mean of 2 values)  AGV-1  G-2  GSP-1  AGV-1  Metal content (p.p .m.) Cu  12  33  60  13  37  63  Zn  85  98  84  82  96  85  Mn  260  331  763  182  209  560  Ni  5  13  19  9*  5*  11*  Co  6  6  14  7*  8*  17*  Metal content (wt. CaO  1.94  2.02  4.90  1.98  2.18  4.86  MgO  0.76  0.96  1.53  0.77  0.99  1.53  Fe as Fe 0^  2.65  4.33  6.76  2.65  4.30  6.20  Na 0  4.07  2.80  4.26  4.07  2.95  4.25  4.51  5.53  2.89  4.14  4.99  2.89  2  2  *Values obtained with background correction (R^ lamp) on Perkin Elmer 303 instrument. **Flanagan (1973)  99 HNO^ - HCIO^ Digestion:  0»5g samples were digested with 10 ml  4 t l n i t r i c i p e r c h l o r i c acid mixture i n 100 ml beakers.  Samples were  refluxed f o r an hour at low heat and then evaporated to dryness. Residues were taken up i n 5 ml 6M hydrochloric a c i d and d i l u t e d to 20 ml with d i s t i l l e d water i n calibrated t e s t tubes.  P r i o r to  instrumental a n a l y s i s , sample solutions were allowed to s e t t l e overnight and the c l e a r supernatant solution decanted.  A n a l y t i c a l pre-  c i s i o n at the 95% confidence l e v e l f o r Cu, Zn and Mn i s - 25%» - 16% and - Jl% r e s p e c t i v e l y . P r e - a n a l y t i c a l treatment f o r Hg Determinationt  The a n a l y t i c a l  procedure i s s l i g h t l y modified from that of Jonasson et a l .  (1973).  0.5g sample was weighed i n t o a t e s t tube and 10 ml concentrated n i t r i c a c i d added.  The sample was allowed to stand f o r 10 min, and  30 ml deionized water added.  The s o l u t i o n was then heated i n a  water bath at 90°C f o r 2 h r , with occasional s w i r l i n g .  After cooling  to room temperature, 10 ml of 5% w/v stannous chloride i n concentrated hydrochloric a c i d were added and the s o l u t i o n aerated. was determined by comparison with s i m i l a r l y treated  Evolved Hg  standards.  A n a l y t i c a l p r e c i s i o n at the 95% confidence l e v e l i n 12 r e p l i c a t e s of 4.  UBC standard rock, with a mean value of 38 p . p . b . , i s - 42%. ( i ) Sulphide Selective Decompositions Aqua Regiat  O . l g samples were digested to dryness with 5 ml aqua  regia (3«1 h y d r o c h l o r i c : n i t r i c acids) i n 100 ml beakers - 10°C.  at 130°  Residues were leached with 2 ml d i s t i l l e d water and 2 ml  hydrochloric a c i d , transferred to a 10 ml volumetric f l a s k and made  100 up to the mark with d i s t i l l e d water. HgOg - Ascorbic Acid: This procedure i s described in detail by Lynch (1971)• at 10 ml.  0.2g samples were weighed into test tubes calibrated  7 ml HgOg- ascorbic acid mixture were added and samples  allowed to stand approximately 18 hr (overnight) with occasional mixing.  Sample solutions were diluted to 10 ml with de-ionized water,  mixed and centrifuged for 5 min to obtain clear supernatant solutions. Working solutions were analyzed using standards made up i n HgOg ascorbic acid. KGlCu - HC1: 0.2g of minus 100 mesh samples were weighed into test tubes (22 x 175mm) and an approximately equal weight of potassium chlorate added, followed by 2 ml concentrated hydrochloric acid. After standing f o r 30 min the solution was diluted to 10 ml with d i s t i l l e d water, mixed and then centrifuged to obtain a clear supernatant solution. Standard solutions, i n i t i a l l y prepared i n potassium chlorate-hydrochloric acid were found to deteriorate within three days, hence, standards were subsequently prepared i n 1.5M HG1, after experiments indicated that matrix effects between standards do not significantly affect absorption (Table XTV").  Analytical  precision for this procedure i s estimated as - 7$ at the 95$ confidence level, on the basis of six replicate analysis of UBC standard rock containing 17 p.p.m. leachable Cu. This efficacious technique has not been used previously in bedrock geochemistry.  Hence, a detailed description of experi-  TABLE XIVs  Effect of composition of standards on atomic absorption.  ug/ml Cu  Percent Absorption 1,5 MHC1  KGLOo-MHCl  HpO^-Asc.  0.5  4.14  4.52  5.27  1.0  8.20  8.64  IO.36  2.0  15.40  16.40  19.02  4.0  28.40  29.80  34.64  102  mental r e s u l t s are presented  i n the following section.  •POTASSIUM CHLORATE - HYDROCHLORIC ACID: SELECTIVE LEACH FOR  A SULPHIDE  BEDROCK GEOCHEMISTRY  (a) Introduction Geochemical contrast between mineralized and unmineralized bedrock can often be enhanced by use of sulphide s e l e c t i v e leaches.  Digestion with aqua regia (Stanton, 1966)  peroxide - ascorbic a c i d (Lynch, 1971)  or hydrogen  has been used f o r t h i s  purpose, but a potassium chlorate-hydrochloric a c i d leach described by Dolezal et_al.(1968), has not been evaluated i n t h i s context. As part of t h i s research programme, an a n a l y t i c a l procedure u t i l i z i n g potassium chlorate and concentrated  hydrochloric a c i d was  developed under the supervision of Dr. K. F l e t c h e r .  Data obtained  by using t h i s method i s compared to data obtained with other p a r t i a l extraction techniques - n i t r i c - p e r c h l o r i c , aqua r e g i a , and hydrogen peroxide-ascorbic a c i d . (b) A n a l y t i c a l Procedure (as described e a r l i e r ) (c) Experimental Work and A s e r i e s of twenty-six  Results granodiorite samples containing  copper contents ranging from 5 to 10,000 ppm and zinc ranging from 18 to 50 PPm were analyzed f o r Cu, Zn, Mn using two cold leaches; * Extract from a paper of same t i t l e : Olade and F l e t c h e r (1974), Journal of Geochemical Exploration, v. 3, ( i n press).  103  two hot acid extractions, and "total" digestion with HF-HNO^HCIO^. Results presented in Figures 24A to 2kD show consistent differences i n relative release of copper and zinc with a l l leaches except HNO^-HCIO^. This i s particularly striking with KCIO^-HCI which liberates up to 100$ Cu^ , compared to a maximum 1  of 28$ Zn..  On the average the ratio of Cus Zn  increases i n the  X  it  order KCIO^-HCI  >  X  '  HgOg- Asc. > aqua regia > HNO^ - HCIO^.  Results obtained with HNO^-HCIO^ are, however, erratic. Another obvious relationship i s the well-defined trend for Cu to increase with CUj.,. to 95-100$ when Cu i s greater than x  t  700 p.p.m. The same trend i s apparent i n data obtained with HgOg Asc.  and aqua regia.  However, the minimum value of Cu increases x  from about 20$ of Cu^ with KG10^-HC1 to a corresponding value of 70$ with aqua regia.  As would be expected this trend i s accompanied  by a decrease i n the value for which Cu becomes approximately equal to Cu (i.e. Gu equals 95-100$ Cu^). t  x  With the HgOg-Asc.  leach, Cu :Cu. declines i n samples containing more than 1000 ppm X  X  CUj. to a minimum of about 30$ • To further evaluate the efficiency of the KCIO^-HCI procedure, G.S.C. ultramafic standards UM1, UM2 and UM4 were analyzed. Table XV compares this data with results reported by Cameron ( 1 9 7 2 ) "^The following abbreviations are used throughout: Me^ - total metal content; Me - metal leached with KC10~-HC1; H^Op - A s c ; aqua regia or HNO* - HCIO^.  104  A. KCIOj-HCI  C. Aqua regia  lOOr  o •  80k  o o o o o o o OS  a  ui io < I-  X Ui  <b ° 8  S  o  0  8  UJ  B. HgOg-Asc.  o  D. HN0 -HCI0 3  4  lOOr  U. O  Ul OC  UJ Q.  60f-  40h  o  °8 °°o  o °orf>  o o o o  100  1000  TOTAL COPPER CONTENT Copper •  FIGURE 24:  (ppm)  Zinc o  Comparison of % of total metal extracted by p a r t i a l techniques.  extraction  105  TABLE XV:  Comparison of leaches on ultramafic standards UM1, UM2 and UM4.  Method  UM  Metal content (ppm) UM2  UM4  I*  3896  951  594  Cu I I  4147  946  538  W  ill  Ni  Co  Zn  *I  .095r/o  I  8013  2590  1945  II  8337  2901  1915  III  0.96$  0.39$  0.25$  I.  236  120  76  II  288  120  66  III  362  178  108  I  35  14  18  III  97  32  63  KClCvj-HCl leach, mean of two determinations  II  H 0 -Asc., data from Cameron (1972)  III  Total metal, data from Cameron (1972)  2  2  106  for HgOg - AsCt extractable metal. 10% of those reported.  Values are generally within  However, for UM2 and UM4 results are con-  sistently high. In view of the promising results obtained on the granodiorite and ultramafic samples, additional experiments were undertaken to evaluate the influence of several experimental parameters on extraction with KClO^-HCl. Neither the extraction period (Fig. 25) nor the amount of KCIO^ used (Table XVl) has an appreciable effect on liberation of copper.  Furthermore, for copper the reaction with both mineral-  alized and unmineralized samples appears to be complete within 5 minutes.  In contrast, for zinc there is a gradual release with  reaction time. Experiments with pure s i l i c a sand indicate; that the observed trend i s not attributable to contamination from the tungsten carbide ball mill during grinding. Influence of grain size was evaluated by grinding two -80 + 100 mesh samples for 30 min in a tungsten carbide ball m i l l . Copper and zinc were then leached from portions of both the original and ground material (Table XVIl). for Cu  x  Results show no significant effect  whereas there i s a marked increase in Zn  x  after grinding.  (d) Discussion According to Dolezal et a l . (1968) addition of potassium chlorate to hydrochloric acid facilitates dissolution of many sulphides - arsenopyrite, chalcopyrite, cinnabar, molybdenite and pyrite are specifically mentioned by their reaction in statu  METAL  EXTRACTED  o  ro  o  CD cz 73  CP  ro cn _ i . ro  3  —•  ro Oi o -•• -h o  \ A  ua (/> -s  -a _ i . cr  <5>  3  Q.  \  3 ro CO r+  • S m ro  OO  fD  r+ 3"  3  ro C a> 3 o  o o  O  N O 5 ° <~ "D O TJ  s= 3  m  33  ro  x  c+ -s  OJ O r+  ro  o o o  O0) 3 D-  ZOT  \  @  CP \  ©  (ppm)  108  TABLE XVI: Effect of amount of KGIO^ added on release of copper with  g KC10  KG10„-HC1  leach.  Copper released (ppm)*  added^  #47  #32  HOI only  7.2  734  •Ig  25.4  2038  •2g  25.0  2022  •5g  26.0  1802  3  * #47 Total copper content 2-9.3 PP^ #32 Total copper content 2059 ppm  TABLE XVII: Effect of grinding on release of copper and zinc with KC10 -HCl leach. o  Treatment  Metal released (ppm) _ „. Copper Zxnc  Unground (-80 + 100 mesh)  25.6  7.2  Ground*  24.5  16.8  Total  29.3  30.5  Unground (-80 + 100 mesh)  2012  5.8  Ground  1936  14.2  Total  2059  33.2  * Ground f o r 30 minutes i n a tungsten carbide-J: b a l l mill  110  nascendi.  In contrast, most silicates are only weakly attacked  by cold hydrochloric acid. Consequently, KCIO^-HCI should be sulphide selective and discriminate against metal held in silicate lattice of fresh igneous rock.  Experimental studies on magnetite  separates suggest that KCIO^-HCI does not remove appreciable zinc from magnetite. It i s extremely d i f f i c u l t to assess the efficiency of a sulphide selective leach since there i s no simple, independent method of estimating silicate versus sulphide metal.  In this study,  criteria based on the geochemical behaviour of copper and zinc are used to compare selectivity of the leaches.  Copper, a strongly  chalcophile element i s generally believed to be present largely as sulphide inclusions even in unmineralized bedrock (Putman, 1972? Graybeal, 1973). Putman (1973) for example, calculates an upper limit of 5 PPm for 'silicate* copper in biotites of granitic rocks. In contrast, zinc, which i s less strongly chalcophile, probably occurs predominantly within silicate lattices of unmineralized samples.  On this basis i t seems reasonable'to suppose that: (i) an efficientlcopper sulphide selective attack will give a high Cu : Zn  ratio in samples unmineralized  with respect to zinc. ( i i ) Cu :Cu. w i l l increase with Cu. as copper sulphide X  T  «  content increases, until in strongly mineralized samples Cu  x  equals Cu  analytical error.  t  within the limits of  Ill  Evaluated against these criteria the KCIO^-HCI, HgOgA s c , and aqua regia leaches, a l l appear to be selective (Figs. 24A to 24C).  However, the Cu sZn X  ratio i s greatest with KC1CL-  X  HG1 and at a minimum with aqua regia. Also Cu tCu. for samples with low copper content i s lowest with KC10.J-HC1 and at a maximum with aqua regia.' On this basis KC10^-HC1 is least damaging to silicates and most selective leach for sulphide copper. (e) Applications to Geochemical Exploration From a practical standpoint, KClO^-HCl appears to have several advantages over other sulphide selective leaches ( i ) for porphyry copper mineralization, the method appears to be more sulphide selective than either HgOg-Asc. or aqua regia; concentrated acids are not involved;  ( i i ) hot  and ( i i i ) the procedure i s  extremely rapid and simple, and hence suited to routine application. Furthermore, the KCIO^-HCI procedure could also be utilized in the field. 1966)  Determinations can be made by either colorimetry (Stanton, or by copper ion electrode.  Results obtained by colorimetry  in 26 granodiorite samples compare favourably with atomic absorption results (Table XVIIl). However, further studies on the action of KCIO^-HCI on a wider range of sulphides (spalerite, molybdenite etc.) and host rocks (volcanics, ultramafics, etc.) are required before i t s general use can be recommended. (f) Conclusions A KClO^-HCl leach i s shown to be sulphide-selective and  TABLE XVIIIi  Comparison of analytical results obtained from KCIO^HC1 digests using atomic absorption and colorimetry (Stanton, 1966)  Sample No.  Cu (ppm) in KC1CL-HC1 Leaches Colorimetric Atomic Absorption 50  2  5°  7  2772  10  2  19  470  600  22  351  500  28  647  700  29  2754  2400  30  8  31  4281  34  !2  35  1545  36  23  50  1775  1500  61  883  1050  114  150  loo  115  572  600  118  263  400  119  1598  1250  173  26  *  <$0  176  33  *  <50  178  125  746  2  * <50  757  151  100  776  544  450  ate #2  49  50  •Lowest detection limit is 50 ppm  3000 *  *  <c50  ^50 5000  *  50 • 1100  *  <50  '  113  t o have advantages o v e r o t h e r procedures  i n estimating sulphide  copper c o n t e n t o f g r a n o d i o r i t e s . On t h r e e u l t r a m a f i c s t a n d a r d s , c o b a l t , copper and n i c k e l v a l u e s a r e w i t h i n 10% u s i n g an a s c o r b i c a c i d - h y d r o g e n  peroxide l e a c h .  of r e s u l t s obtained  CHAPTER FIVE . REGIONAL GEOCHEMISTRY  115  INTRODUCTION Identification of lithogeochemical halos i n igneous environments i s dependent on a broad understanding of the chemistry and evolution of magmas, and the nature of primary processes which give rise to genetically related metal concentrations . Brabec (1970) and Brabec and White (1971) have investigated distribution of major and trace elements in fresh rocks and minerals from the Guichon Creek batholith.  Their findings suggest  that metallization processes which gave rise to porphyry copper deposits are closely related to petrochemical evolution of the pluton.  To further the understanding of relationships between major  and trace elements and to provide adequate background geochemical data, .60 fresh rock samples (Fig. 26) collected and described by Northcote (1968) and Brabec (1970), and supplemented by samples from the author's collections were analyzed for selected major elements.  In addition, results of 20 major element analyses  compiled by Brabec (1970) are included in the plots of chemical variation diagrams. RESULTS (a) Major Elements Results of major element analyses are presented together with normative composition i n Table XIX, and as functions of the Larsen Differentiation Index (ID I =  l/3Si0 + KgO - CaO + MgO + 2  116  Ni col a Group Hybrid Phase Guichon Phase Chataway Phase Bethlehem and Skeena Phases Witches Brook and Bethlehem Porphyry Phases Bethsaida and Gnawed Mountain Phases  L  N  2ml  0 6 f 112.  :  IGURE 26:  Location of samples used in regional study, Guichon Creek b a t h o l i t h (After Brabec, 1970; Northcote, 1968)  117  TABLE XIX:  Means, ranges and mean normative composition . of-intrusive, unj^sy. Guichon Creek batholith '(Values i n wt. %) riTKl.-H£M PCSKf.'Sr  NICOLA VOLCANJCS 15) sio  2  (1'-)  (6)  (C)  SESEliA (5)  (6;  (e;  66.0ft  6:.zi  65.23  CliATAVAY  16.6? 16.37 17.00 16.91 . J.03-17.Cr 16.24-1774 15.15-17.52 15.11-17.6? ft.oft >;.4i i.uft i.3i w47 ft.ft9-6.63 3.25-5.80 3.11-3.72 3.51 - 11.20 5.5S-?." ft.26 ft. 05 5.78 5.15 6.73 3.36-10.e* ••(.95-6.60 ft.37-6.10 64-5.27 3.07-5.21 3.16 1.89 1.31 ft. 89 2.31 2.20-3.82 l.oft-3.28 1.30-2.30 1.10-1.63 1.17-9.59'  16.08 11J.50-10.1H  3  f  CaO MqO Na 0  3.39 2.20-4.22  K,0  0.20-1.32  2  0.62  3.61 3.40-4.21 l.-A 0.97-2.30  ft. 06 3.83-4.58 i.yv  1.-2  3.99-2.6ft  1.52-2.89  TIC,  0.60 0.53-1.3*  0.7ft 0.64-0.80  O.65 0.511-0.72  C 25  0.15 0.1ft-0.17  C.16 O.lft-0.22  0.17 O.lft-0.22  AAnO  0.15 0.07-0.19  0.11 0.03-0.1ft  0.C8 0.06-0.10  3  ft.52 ft.29 3.06-4.95 3.85-4.89 i.83  BETHSAIDA Leucocratl-:  (ft;  (2.2ft 64.37 6C.02 56.12 JO.1*0 -68.32 •,9.23-61.24 57.cO-6ft.20 61.46-67.4f 65.J1-65.&- 67.3B-69.5v 63.03-77.56  2  Ai 0  oyici'.oN  HVBR'O  WITCHES bSOOK.  15.54 15.21 14.46-16.16 11.56-16.50  (5)  66.00 74.32 £3.24-68.34 69.J1-77.K 15.85 14.57-16.:2  2.^~ 2.E0-3.4? 3.84 3.73-3.91 1.02 0.6O-I.53  3.03 1.26-3.85 307 0.35-4.02 1.36 0.60-1.78  3.55 3.20-4.53 1.43 0.92-1.88  ft.78 ft.3S-5.15  3.87 3.37-4.15  4.73 4.72-4.92  63.79 61-70.ci  0.35-4.52 0.41 0.12-0.87  q.54 0.40 0.82  4.17  4^33  3.37-4.72  4.33-5.31 1.96  r  0.35 0.22-0.41  0.39 ' 0.2E-0.46  0.42  0.29  0.34-0.49  0.1ft 0.13-0.14  0.14 0.13-0.15  0.11 O.W-0.15  0.1ft  0.12  0.13  0.14-0.15  0.04-0. IJ  0.03-0.1ft  .0.07 0.07 0.06-0.07 0.06-0.07  O.Oft-0.05  0.05  0.05 ' 0.02-O.C6  0.02  0.18-0.43  0.02 .  0.02-0.03  0.01-0.03  2.ft9 1.43-3.01  3.51 2.15-2.98 2.67-4.12  3.15 0.21-3.68  0.16 O.lft-0.22  70.87 73.14 63.27-72.55 72.61-74.32  1.91 1.54-2.30 2.83  2.56  0.37 0.30-0.41  (4)  1.39 0.4J- 1.3 2.01  1.77-3-41  0.1(9 O.ftO-0.62  (3)  15.92 14.22 lft.ftl 14.S1-17.02 12.76-lJ. 39 13.26-15.0]  2.19  I.30-I.S£  Porphyry  11.0-16.10  1.63-3.29  1.32-2.40  1.73.  4.18 3.41-4.6=  13.72  (»  Fcrpryrltlc  0.6« 0.57-1.03 ft.78  1.17. 0.95-1.55 2.12 1.78-2.54 0.3ft 0.23-0.46 ft.74  ft.76-ft.85 ft.52-ft.85 1.81 2.08  1.80-2.29 1.74-1.87 0.27 0.29 0.22-0.39 0,24-0.31 0.12' 0.12-0.13  1.07-2.2ft 0.20 0,18-0.22 0.12 0.11-0.13  0.06  0.15  0.04  O.Cft-O.07  O.O3-O.O5  0.03-.0.06  C.I.P.". noma  Quart? Orthoclase  12.45  15.38  16.63  21.65  22.69  24.94  29.37  19.34  33.49  28.88  23.60  33.41  5.0C  10.30  11.96  11.67  11.00  10.36  13.08  15.33  18.71  10.69  10.80  .12.51 40.81  AlMte  29.57  31.32  34.94  36.6ft  38.39  40.96  33.C9  ftO.56  35.45 '  41.74  40.84  Ancrthlte  27.0ft  25.35  22.66  20.67  19.50  16.78  15.17  14.64  . 9.24  13.48  12.11  9.91  ^Pyroxene  18.0ft  12.22  9.31  4.8ft  3.79  ?.6l  ft.36  6.23  I.03  1.73  5.00  1.03  Kagnetite  5.99  3.83  2.63  3.05  2.67  2.36  2.02  2.79  0.92  1.41  Tlnenlte  1.82  1.57  1.26  0.86  1.43  0.96  0.27  0.67  0.75  0.61  0.55  0.52  O.56  C37  0.39  0.41  0.39  0.39  0.34  0.3ft  0.3ft  0.3ft  0.29  0.32  0.29  0.29  0.08  1.25  _  o.eo  Apatite Corrundur; Rutlle Vtematlte  .  _  1.02 0.01 -  •Total Fe as F e ^  0.01  0.01  -  0.01  -  _  »?e0 calculated by using TcOfre^  ration ln 2ft samples  (Brabec, 1970). 1  2 Arithmetic Beans  'Total normative ortho- and cllnc-pyroxenes.  'calculated by cor.puter program  (::0!i..) provided v  by A..'.  Sinclair.  -  _  0.01  118  Fe as FeO  ) i n Fig. 27.  As shown i n Table XIX, abundances of  most major elements vary i n accordance with relative ages of the rock units as deduced from contact relationships by Northcote (1969)• Thus the intrusive units generally become more f e l s i c from the relatively oldest to the youngest.  Rocks of the Witches Brook  and Chataway Phases show the greatest variations in element values. Chemical variation diagrams (Fig. 27) show that SiCv, and NagO concentrations increase with LDI, whereas MgO, CaO total Fe as FSgO-j, Ti0 , AlgO^ and PgO^ show a concomitant decrease. 2  1C,0 shows no appreciable change with LDI, except for dyke rocks of the Witches Brook and Bethlehem Porphyry Phases which exhibit considerable enrichment. Furthermore, excluding the aforementioned K-rich rocks, concentrations of KgO i n the remainder of the batholith range from 0.21 - 2.89% with a mean value of 1.85%. These values are low compared to the average value of J.0k% quoted by Turekian and Wedepohl (1961) for high-Ca granites.  A lack of  enrichment in KjO values i n the relatively younger units of the batholith i s reflected in the near constant average modal proportions of K-feldspar, and decreasing values pf modal biotite with decreasing age and increasing differentiation (Northcote, 1969). On an AFM diagram (Fig. 28), enrichment i n total alkalis relative to MgO and CaO i s evident.  This trend i s similar to those  found in typical calc-alkaline volcanic-plutonic complexes (Nockolds and Allen, 1953). However, on the CaO-NagO-KpO variation diagram (Fig. 29)» two trends are present. The f i r s t , manifested by dyke rocks of the Witches Brook and Bethlehem Porphyry Phases,  119  0.8 Ti0  A  A  A  °  o.4  2  A  O o bo -  TiO,  & o  CaO  +  CaO  A  MgO  A  AAAA °Q  2\  n.  a 9  o  • £  O  + ++  +  MgO *AA O-  | A  . AA O-  A  A  Fe 0 2  0°  A  8* •  3  3  Total FeF eas0 2  3 + + +  K 0.  A  2  A  A  A O  °° ? °" i *  • a  •  •  a  +?  e  KQ N a2 0 2  Na 0  o  2  \ A ° A A ° A A £ §£>  A1 0 2  Al 0  3  2  Si0  Si0  • -  8'  ^S^v  0  0  ++_ +a  3  a a  a B  2  o  2  MM  +  9  A^AAoAAA> ° O 15  10  20  25  [1/3 S i 0 + K 0] - [CaO + MgO + FeO] FIGURE 27- V a r i a t i o n diagrams i n Guichon Creek rocks showing major element concentrations (wt.*) versus Larsen d i f f e r e n t i a t i o n index (For legend, see F i g . 28) 2  2  LEGEND  (sFeasFeo)  FIGURE 28:  A •  Nicola Volcanic Rocks Hybrid Phase  AFM v a r i a t i o n diagram f o r rocks of Guichon Creek batholith.  KoO  Nicola Volcanic Rocks Hybrid Phase Guichon and Chataway Phases Bethlehem Phase Witches Brook Phase Bethsaida and Gnawed Mountain Phases  Na,o  FIGURE 29:  CaO-NaoO-I^O v a r i a t i o n s for rocks of Guichon Creek b a t h o l i t h  CaO  122  shows enrichment in K^Q relative to GaO and NagO (normal calcalkaline trend), whereas the other trend i s toward ment. According to Larsen and Poldervaart  (1967)» the latter  (1961)  Na 0 enrich2  and Taubeneck  trend i s commonly characteristic of petro-  chemical differentiation i n rocks of trondhjemitic a f f i n i t y . In both the AFM and CaO-NagO-KgO variation diagrams, 5 analyses of Nicola volcanic rocks plot along the same "liquid line of descent" (Nockolds and Allen, 1953) as rocks of the Guichon Creek batholith (Figs. 28 and 29). (b) Trace Elements (i) Introduction Abundance data for selected trace elements are summarized in Table XX. These results provide data on background values f o r elements of speciric interest, and also corroborate major element trends.  Trace elements of especial interest are;  ore metals} Friedrich,  ( l ) Cu, S and Mo  (2) potential pathfinders, Hg, (Hawkes and Webb, 1962}  1971),  Ba (Warren et a l . ,  B  (Boyle,  1974),  1971),  Rb (Armbrust et a l . ,  Cl, F (Kesler et a l , ,  1971)  1973) and Ag}  Sr,  and  (3) elements related to primary lithologies, Zn, Ni, Co, V and Mn, Brabec  (1970)  studied background trace-element content of  rocks within the batholith, and his data w i l l be referred to wherever appropriate.  However, i t should be noted that the majority of  Brabec's (op. cit.)  data were obtained by sulphide-selective aqua  regia digestion rather than total extraction employed in this study. Mo, Ag and Pb are generally below detection limit whereas  TABLE XX: *Keans and Ranges of Trace Elements in rocks of Guichon Creek Batholith.  NICOLA VGLCAKICS w  24  4 - 52 **Cu •'•Zn -••*Zn  15 92  39-141  36 40  ••Kl  Co  l  4-134 . 14  5-25  HYBRID  (5) 51  12-1143  57 74  68-81  31 33 15-44 13  II-35  K0  2  2  ^b  5  5 0.1  2  h  e  3  2  •-Ba 2  V  0.1 14  10 - 15 200 100-400  150  20-200  5 500  400-600  83 50-100  . GUICHOI:  CO  67 30-95 65 60  47-76 27  27 16-38 12  (7) 45  16-240  43 45  37-72  25 20 9-32 11  2  8-15 2  5  5  11-13  0.1  15 5-20 300 200-500  50  40-60  HF-HCIO^-HKO^ total digestion ^Emission epectrography  CHATAVAY  0.1  5 500 300-600 39 20-50  BETHLEHEM  (6) 33 11-195  32 39  33-46  19 12  6^24  8 6- 9 2 5 0.1  5 560  500-800  34  30-40  SKEENA  (5) 26 9-45  -  33  22V35  8 6-10  8  6-10 2  5 0.1  5 550  500-600  26  20-40  * Geometric mean ** Aqua regia extractable metal (3rabec, 1970)  WITCHES BROOK  BETHLEHEM PORPHYRY•  (7) 47  (7) 43  10-88 42  30  22-127  -  17-41  19 10-31  17  -  10  6-14  6 5-9 2 5 0.1  5 600  7 4- 9 5 2-7  30-50  (6) 19  4-135  10-40  28  2-33  5 5- 6 5 3- 7  5 3- 6 5 4- 7  5  25  _  _  5 5  (7) 8 3-15  22  2  0.1  GNAWED MOUNTAIN  10  29 15-37  2  500-600 40  1  3ETHSAIDA  0.1  5 520 500-700 15 10-20  ALL GUICHON SAMPLES  (54) 39 43 40 27 14  8  2  2  5  5 0.1  0.1  8 5-10  15 10-20  5 504 45  124  Ba and B do not show significant variations and results of Hg are extremely erratic (Table XXII).  Consequently, results for these  elements are not discussed further. ( i i ) Distribution of Copper With the exception of rocks from the Witches Brook and Bethlehem Porphyry Phases, mean Cu contents generally decrease from the relatively older units at the outer margins to relatively younger at the core (Table XX ). 1  Brabec and White (1970) reported a  similar distribution for aqua-regia-extractable Cu in 300 samples from the batholith (Table XX and Fig. 30b).  A plot of Cu values  versus LDI shows a considerable scatter, although a trend towards decreasing Cu as LDI increases i s evident (Fig.  30a).  Geochemical behaviour of Cu in silicate melts during magmatic differentiation i s not well understood (Al-Hashimi and Brownlow, 1970). Wager and Mitchell (1951) in their classical study of Skaergaard intrusion, found that during the early and main phases of magmatic differentiation, Cu contents of the constituent minerals and whole rock increased, whereas after 90% solidification (Wager and Brown, 1967)» °st minerals were suddenly depleted in m  Cu.  Simultaneously, whole-rock S showed a sharp increase, although  whole-rock Cu did not change appreciably.  The redistribution of  Cu and increase in S were attributed to a separation of an immiscible sulphide phase which occurred near the end of the fractionation process.  Similar, though less extensive studies on other  lntrusives tend to confirm the pattern observed for the Skaergaard  !  1000-  r =-0.51 IOOH  +  10'  10  15  20  25  LDI (Larsen D i f f e r e n t i a t i o n Index) FIGURE 30a:  D i s t r i b u t i o n of Copper in r e l a t i o n to Larsen d i f f e r e n t i a t i o n index (Legend as f o r F i g . 29)  FIGURE 30b:  Regional d i s t r i b u t i o n of aqua regia extractable Copper in rocks of Guichon Creek b a t h o l i t h (After Brabec and White, 1971)  126  rocks (Cornwall and Rose. 1967$  McDougall and Lovering, 1963).  In the Guichon Creek batholith, the tendency for Cu to decrease generally with increasing fractionation parallels the behaviour of Fe and Mg (Fig. jk)',;,  v  A plot of Cu versus Fe shows  a significant but relatively weak correlation (r = 0.4l)(Fig,. 31),  ^ .fr suggests that Cu  This  .f.„fr (0.72A) may to some extent substitute  (0.74A) in silicates and oxides.  for Fe  However, from theoretical con-  siderations, Ringwood (1955) has concluded that due to differences in electronegativities, Cu  would form weaker bonds than Fe  resulting in a concentration of Cu i n residual melts.  ,  Curtis  (1964) pointed out that crystal-field effects could result in the exclusion of Cu from crystal structures in preference for Fe.  Cu  is strongly chalcophile, and generally combines with S to form sulphide grains. These commonly occur as inclusions in silicates or may even concentrate as ore deposits. Results of sulphideselective, partial extraction techniques further support the dominant sulphide mode of occurrence of Cu (Olade and Fletcher, 1974). On this basis Zlobin et a l .  (1967) have concluded that the positive  correlations between Cu and Fe reflects only similarity in geochemical behaviour rather than ionic substition. ( i i i ) Distribution of S, Rb, Sr, Cl and F S content of 38 unmineralized samples i s presented i n Table XXI.  Average S content in the various intrusive units are  not appreciably different, although the porphyritic rocks of the youngest Gnawed Mountain Phase are relatively enriched in S.  Mean  127  * r = 0.411 *n = 40  100(M  Cu '9P1 (p.p.m.)  I* 0  +  ++ + + +  •  •  A  B of  •a  *d*  °  Total Fe as % F e 0 2  FIGURE 31:  3  Relationship between Copper and Iron in rocks of Guichon Creek b a t h o l i t h . (Legend as f o r F i g . 29) *(excluding Witches Brook and Bethlehem Porphyry Phases)  TABLE X X I i  Abundances o f o u l p h u r , r u b i d i u m and s t r o n t i u m l n r o c k s o f Guichon Greek B a t h o l i t h .  •Sample Kumber  0-6319 0-63221 0-63224 1-6352 1-6470  Rock U n i t  • ::icou  •  HYBRID  1-6494  21-63140 21-63206 21-64117 21-64151 21-6456 22-6479  CHATAVAY  • Sulphur ( l n ppm)  ?.ubld'i\un ' L j t r o n l i u m ( i n ppm) . ( l n ppm)  346  35  382 530. 310 354 475 444  37 36. ' 82 51 5' 37  70 52 -74  340 609  293 • 363  22-63243  373 553 38O  22-64161 4-64186  BETHLEHEM  1  4-6467 4-6461 4-63101 41-63184 41-63214 41-72185 5-64105 5-6430  BROOK  333  51-721453  BETHLEHEM  555  PORPHYRY  247  51-721365 51-721367 51-721370 51-721358 6-6463 6-72750 P- 72 1 11 f-72115  76 . 4  51 .67  71  440  SKEENA  -  500 459 300 413 291  WITCHES  '  312  524  3STHSAIDA  GNAWED :-:OIT.;TAI:;  8-721  S-7215  746  18  857  42  . 892  52 26 36 132 103 • 82 86 85'  625 680  655 420  562 249  368 331  d.n.a.  46  733  376 272 371 751 377 475 273  4 35  865 528 599.  35 35  36 32 33  •Sample number ( A f t e r . - N o r t h c o t e , i y 6 0 | d.n.n.  692  581.  42 48  395  73^  82  621 341  24  d.n.a.  681  80  22-6920 22-6333 22-6341 '  298  •  597 750 710 719* 1000 756 696 609 603  340 .  22-64201  727  52  22-64132  22-64141  255 566 582 784  18  282  GUICHON  264 282 201  Dntn l i o t A v a i l n b l o f l u o r e s c e n c e nrmlv3lc.  .591  635 612 567 and i f r a b e c , 1970  TABLE XXIIi  ** Abundaces of mercury in rocks of Guichon Creek batholith  * Sample Number  Rock Unit  0-6319  Mercury (in p.p^b.)  liicola  100  0- 6319  4  1- 6925  '  4  1-63186  4  1-63167  .  21-6346  4  Chataway  4  21-63140  no  21-64151  120  21- 63202  35  22- 6333 22-6341  Guichon  55  •  1  1  2  22-64132  4  22-64201  85  4- 64132  Bethlehem  5  4~.6IJ.62 41-72185  155 Skeena  5  41-63184 5- 6430  71 Witches Brook  4  5-6912  4  5- 64120  4  51-721340  Bethlehem  5  51-721353  Porphyry  20  51-721358  5  51-721370  6  6- 63237  Bethsaida  80  6-6463  6  6-63128 8-721  .  5  270 Gnawed Mountain  ,  10  8-72111  1  0  8-72115  1  0  8-72105  5  *  Sample numbers (after Korthcote 1968; and Brabec, 1970)  **  Flaraeless atomic absorption analyses  129  130  value for a l l Guichon rocks i s 390 ppm which Is similar to the value of 300 ppm cited as the world average for S in intermediate igneous rocks (Turekian and Wedepohl, 1961). Rb concentrations i n 39 samples range from 4 to 132 (Table XXI) and average 38 ppm.  ppm  Compared with the average value of  110 p.p.m. for intermediate igneous rocks, the Guichon Creek bathol i t h i s impoverished i n Rb,  However, values are comparable to those  obtained for the Sierra Nevada batholith (Kistler et a l , ,  1971)  and the Coast Mountain intrusions (Culbert, 1972), When rock units within the batholith are compared, surprisingly there i s no consistent difference i n mean values although the K-rich rocks of the Witches Brook Phase are relatively enriched in Rb,  Geochemical  behaviour of Rb i s influenced by the abundance of K (Nockolds and Allen, 1953?  Goldschimdt, 1954)  for which Rb substitutes in  a l k a l i feldspars and micas (Heier and Adams, 1964), A plot of K^O versus Rb shows a strong positive correlation (r = 0.77;  Fig.  32a).  Thus, absence of appreciable variations i n Rb levels i s closely related to a similar behaviour by K ( F i g . .27);;-,.  However, a pre-  liminary plot of K-,0 against K/Rb ratios show a negative slope (r = -0,41) which suggests enrichment of Rb relative to KgO i n rocks with high KgO values (Fig, 32b),  although rocks with high K levels  are not the most differentiated. The K/Rb ratio i s generally considered as a reliable index of differentiation i n most igneous rock suites (Taubeneck,  1965). However, for the Guichon Creek batholith, K/Rb ratios show no consistent patterns when plotted against LDI (Fig. 33).  This i s  J  '  FIGURE 32:  1 1  ..:• KO % 2  1 2  1  3  Relationship between rubidium and potassium in rocks of Guichon Creek b a t h o l i t h .  132  T HBethsaida Phase ••  IOOOH  8001-  K/Rb  600 h  400  D  Bethlehem Phase  9  Guichon and Chataway Phases  A  \  Witches Brook Phase  Hybrid Phase  n = 32 r = -0.41  a  \.  h  \  200V  ®  •• A  FIGURE 32b:  Plots of K/Rb vs K i n rocks of Guichon Creek b a t h o l i t h .  150  O  r = -0.68 n = 33  100h  Ca/Sr 501>  o  <*  0-  IOOOL r = -0.06 n = 33  800r-  6001-  K/Rb  •• •  4301-  200l>  © H  I  10  FIGURE 33  15  i_  20  i  25  LDI (Larsen D i f f e r e n t i a t i o n Index) Plots of K/Rb and Ca/Sr versus Larsen d i f f e r e n t i a t i o n index.  1  134  attributed to the relatively low and near uniform concentrations of both elements in the Intrusive units. Sr concentrations range from 249 to 1000  p.p.m. and  average 686 p.p.m. These values are high relative to the average of 440 p.p.m. cited by Turekian and Wedepohl (196l) for high-Ca granitic rocks. As shown in Table XXIV, mean Sr values are slightly lower in the more f e l s i c rocks. During magmatic processes, Sr tends to substitute f o r Ca and K i n feldspars.  Thus, the apparent  decrease of mean Sr concentrations with increasing differentiation might reflect a corresponding decrease i n Ca levels.  A plot of  Ca/Sr ratios against LDI indicates a decrease with increasing differentiation (Fig. 33).  This relationship suggests that Sr i s  enriched relative to Ca in more f e l s i c rocks. Abundance of Cl and F in 12 samples are tabulated in Table XXIII.  Cl content i s highest i n the more mafic Hybrid and  Guichon Phases, and values generally decrease in the more f e l s i c rocks. F concentrations range from 108 to 38Q p.p.m. with an erratic distribution.  Compared to the world average of 130 p.p.m.  Cl and 520 p.p.m. ' F (Turekian and Wedepohl, 1961; Sandell, 1953)  Kuroda and  f o r intermediate rocks, results indicate that the  Guichon Creek batholith i s relatively enriched in Cl but impoverished in F.  Kuroda and Sandell (1953) and Allmann and Kortnig  (1972) suggest that the halogen content of igneous rocks may be related to regional tectonic and crustal features, such as island arcs.  TABLE XXIII:  Abundances of *chlorine and * f l u o r i n e i n rocks of Guichon Creek batholith  Intrusive  Sample  Unit  Number  Guichon  Bethlehem  Skeena  Fluorine  (p.p.m.)  (p.p.m.)  880  380  22-6432  544  380  22-6341  465  284  4-6462  240  108  4-63184  280  140  41-72185  100  240  1-6470  Hybrid  Chlorine 1  Witches Brook  5-721370  128  256  Bethsaida  6-6463  132  176  6-64631  132  180  6-72750  80  208  8-7215  92  172  120  224  Gnawed Mountain  8-72111  *  Ion-selective electrode analyses  136  (iv) D i s t r i b u t i o n of Zn. Mn, N i , Co and V Zn values generally decrease from more than 80 p.p.m. i n the Hybrid Phase to l e s s than |o p.p.m. i n the r e l a t i v e l y younger Bethsaida and Gnawed Mountain Phases. bution was reported by Brabec and White  (1971)  A similar d i s t r i f o r aqua regia-  extractable Zn (Table XX). Although a plot of Zn versus LDI shows considerable scatter, two trends with no genetic s i g n i f i c a n c e are evident ( F i g . 34).  The f i r s t which i s considered "spurious", has  a r e l a t i v e l y steep slope and Includes rocks of the Hybrid, Witches Brook and Bethlehem Porphyry Phases.  The second trend considered  "normal" joins rocks oft/the other phases.  The "spurious" trend i s  attributed t o extensive contamination of the Hybrid Phase by r e l a t i v e l y Zn-rich N i c o l a rocks, and strong depletion of Zn i n the K-rich dyke rocks of the Witches Brook and Bethlehem Porphyry Phases. Fe  i n s i l i c a t e s and oxides because of s i m i l a r i t y i n i o n i c pro-  perties. (Fig,  During magmatic processes, Zn generally substitutes f o r  A plot of Zn versus'Fe shows a strong positive c o r r e l a t i o n  35)•  Comparable r e s u l t s have been reported f o r other g r a n i t i c  rocks (Haack,  1969;  Blaxland,  1971).  Results of p a r t i a l extraction  techniques a l s o indicate that Zn, unlike Cu, i s p r i n c i p a l l y associated with the s i l i c a t e f r a c t i o n (Brabec, Fletcher,  1971J  Foster,  1973?  Olade and  1974). Mn d i s t r i b u t i o n shows the same trends as Zn.  Values  generally decrease with increasing d i f f e r e n t i a t i o n (Table XIX and Fig,  34).  F i g . 36 demonstrates the covariance of Mn and Fe. This  137  A  Hybrid Phase  o  Guichon Phase  9  Chataway Phase  a  a •  Bethlehem and Bethlehem Porphyry Phases Witches Brook Phase Bethsaida and Gnawed Mountain Phases  Larsen D i f f e r e n t i a t i o n Index FIGURE 34:  V a r i a t i o n diagrams in Guichon Creek rocks showing trace element concentrations plotted against LDI  138  100  A  * r = 0.89  A  A •  *n = 40 50H  0  8  40  +  30  Zn (p.p.m.)  +  a  0  B  +  a  20  id—-XL FIGURE 35:  2  3 4 5 6 7 8 Fe as in percent ^^2^3 Relationship between Iron and Zinc in rocks of Guichon Creek b a t h o l i t h (52 samples) *(excluding Witches Brook and Bethlehem Porphyry Phases) (Legend as f o r Fig. 29)  139  80CH  A A  •  A  A  •  50CH  + +  *r = 0.33 '•*n = 40  Q  +  +  +a  o  200-  0  Mn (p.p.m.)|  B  100H  B  504  '  1  1  2  1  .3  1  4  '.  —I  5  I  6  I  7  L  8  Fe as % Fe203 FIGURE 36:  Relationship between Iron and Manganese in rocks of the Guichon Creek batholith (52 samples) *(excluding Witches Brook and Bethlehem Porphyry Phases) (Legend as for Fig. 29)  140  r e l a t i o n s h i p i s consistent with Mn"*" ( i o n i c size 0.80A) s u b s t i t 1  uting f o r Fe  (ionic size  0,74A) i n femic  silicates.  Mean values f o r Ni, Co and V f o r constituent rock units of the b a t h o l i t h are summarized i n Table XX. Plots of these elements against LDI indicate a general decrease with increasing magmatlc d i f f e r e n t i a t i o n ( F i g . 34).  A s i g n i f i c a n t positive  c o r r e l a t i o n between N i and Co and Fe and Mg ( F i g . 37 and 38) i s consistent with Ni sund Co s u b s t i t u t i n g f o r Fe and Mg i n f e r r o magnesian s i l i c a t e s . DISCUSSION Petrochemical trends suggest that the zonal and composi t i o n a l variations exhibited by rocks of Guichon Creek b a t h o l i t h conform with a model of f r a c t i o n a l c r y s t a l l i z a t i o n of a magma of intermediate composition by progressive f r a c t i o n a t i o n of plagioclase of intermediate composition, hornblende and b i o t i t e .  Plagioclase  f r a c t i o n a t i o n generally depletes the Ca content of derivative f l u i d s , whereas b i o t i t e and hornblende f r a c t i o n a t i o n tends t o enrich S i and a l k a l i content and deplete Fe, Mg and T i l e v e l s of derivative f l u i d s (Peto,  1973;  Smith,  1974).  The most s t r i k i n g aspect of the petrochemical evolution of the b a t h o l i t h i s the absence of K^O enrichment  i n the most  d i f f e r e n t i a t e d and r e l a t i v e l y youngest rocks - the Bethsaida and Gnawed Mountain Phases.  Low values of KgO and lack of enrichment  with increasing d i f f e r e n t i a t i o n suggest e i t h e r that the pluton i s not highly d i f f e r e n t i a t e d o r that the parental magma i s  141 A'  40'  0  •  A  •  + + + + + +  51  E +  +  (3 +  Ni (p.p.m.)  * r = 0.78 *n = 40  • +  2  4  6  8  Fe as % Fe203 FIGURE 37a:  V a r i a t i o n of Nickel with Iron in rocks of Guichon Creek b a t h o l i t h (Legend as f o r F i g . 29)  40  •  A •  KH  A  •  •  El +  ++  ca  s  ++ n-  * r = 0.73 *n = 40  Ni (p.p.m.)  2  3  % MaO FIGURE 37b:  V a r i a t i o n of Nickel with Magnesium i n Guichon Creek b a t h o l i t h (*excludina wit^u Brook and Bethlehem Porphyry PhasSs ! % W  t  (  s  142  50  e  ® 0  104  6A  n ® ®  Co (p.p.m.)  A i A  °a as + +  +  i LB 8§ HQ  s ++ + a + 0.84 *n = 40  Fe as % ? 2®3 Relationship between Cobalt and Iron in Guichon rocks (*excluding Witches Brook and Bethlehem porphyry phases). Legend as f o r F i g . 29. e  FIGURE 38a:  401  9  O  10 Co (p.p.m.)  •  + + +  +  9  0  • +  B0 •  9  A  ©  A  0 0  ++  0.83 *n = 40  + 0 0  % MgO FIGURE 38b:  Relationship between Cobalt and Magnesium in Guichon rocks (*excluding witches Brook and Bethlehem Porphyry Phases) (Legend as f o r F i g . 29)  143  relatively K-poor (Taubeneck, 196?).  The latter i s probably  the case because petrographic evidence (Northcote, 1969)  and  petrochemical variation diagrams (Figs. 27 and 34) support magmatic differentiation.  Absence of appreciable variations in Rb and  K/Rb  with increasing differentiation might be related to similar behaviour by KgO.  Furthermore, the tendency f o r NagO concentrations  to increase with Increasing differentiation (trondhjemitic trend) i s commonly characteristic of K-poor magmas (Larsen and Poldervaart,  1961;  Taubeneck, I965). Petrochemical evidence suggests that the K-rich dyke  rocks of the Witches Brook Phase and some of the Bethlehem porphyries are either not cogenetic with the remainder of the batholith or might be related to local *high-level' phenomena during evolution of the batholith (Northcote, 1969). Trace element distribution i n igneous rocks i s generally controlled by abundance of major elements and the a b i l i t y of the trace elements to enter appropriate crystal lattices.  Trace elements  capable of entering the structures of rock-forming minerals are removed from the magma, and thus eliminated from any further possibility of concentration into ore deposits (Levinson, p. 50)•  1974;  The behaviour of Cu suggests that Cu does not readily enter  into crystal lattices of femic silicates.  Because of i t s strongly  chalcophile nature, Cu fractionates into the residual melt to combine with S (Wager and Mitchell, 1951). With increasing differentiation and volatile content, and an adequate supply of S, copper  144  sulphides might concentrate as ore deposits i f the magma i s Curich.  The spatial and temporal association between porphyry Cu  deposits and the most differentiated and r e l a t i v e l y youngest i n trusive units i n the batholith may be relevant i n this context. Thus, according to Brabec and White (1971), the low Cu content of the most differentiated rocks of the Bethsaida Phase might be equated with the presence of epigentic Cu deposits. However, the tendency f o r Cu to decrease with increasing differentiation parallels that of the femic elements (Zn, N i , Co, Mn and ? ) , and i s most chara c t e r i s t i c of Cu-poor magmas (Sheraton and Black, 1973)* However, i t i s not clear whether the role of the batholith is" one of structural control rather than a source of metals (Noble, 1970). These aspects of ore genesis are discussed further i n Chapter 8. Zn, N i , Co, Mn and V are less chalcophile than Cu and more readily enter l a t t i c e s of ferromagnesian minerals. they are removed from the magma during differentiation.  Consequently Low abundances  of Mo, Pb and Ag i n rocks of the batholith reflect the i n i t i a l concentrations i n the magma. However, f o r Mo, magmatic differentiation resulted i n concentration i n the residual melt which formed deposits.  M0S2  Hg, B, Cl and F are enriched i n v o l a t i l e fractions of  residual melts and subsequently are concentrated i n zones of mineralization as hydrothermal minerals or i n f l u i d inclusions. From the foregoing, i t i s concluded that petrochemical trends could be useful i n identifying rocks that are most d i f f e r entiated and capable of being associated genetically with ore deposits.  In the Guichon Creek batholith, the most differentiated  145  rocks may be identified easily by concentric zone relations and petrologic c r i t e r i a .  However, as Peto  (1973)  has shown, many  plutons, for example, the Simllkameen and Iron Mask batholiths i n British Columbia are not concentrically zoned and petrological criteria might not be very useful i n determining the differentiation sequence and oogenesis of the intrusive units.  In this situation  petrochemical studies could be useful in reconnaissance exploration. Furthermore, the close relationship between trace element levels and magmatic differentiation emphasises the need to assign for exploration purposes, different threshold and background levels to each intrusive phase . SUMMARY AND CONCLUSIONS (1) Major element variations are consistent with a model of fractional crystallization of a calc-alkaline d i o r i t i c magma by progressive fractionation of plagioclase, biotite and hornblende. By this process, derivative fluids were enriched ln Si and Na and depleted i n Ca, Fe, Mg and T i . (2) Dyke rocks of the Witches Brook Phase d i f f e r considerably in major and trace element contents, and might represent either a product of local *high-level' crystallization or otherwise not cogenetic with other intrusive units of the batholith. (3) The relatively low and near uniform K concentrations and the trondhjemitic trend exhibited by rocks of the batholith i s suggestive of a K-deficient magma.  146  (4) Variations  i n Mn,  Zn, Ni, Co and V are  associated with degree of f r a c t i o n a t i o n .  intimately  Strong positive  correlations with Fe and Mg indicate p a r t i t i o n i n g of these elements into s i l i c a t e f r a c t i o n s during magmatic (5)  (evolution.  Cu content generally decreases from the r e l a t i v e l y  to youngest and most d i f f e r e n t i a t e d u n i t s .  oldest  This pattern of  v a r i a t i o n p a r a l l e l s those of other 'femic* elements, r e f l e c t i n g normal d i f f e r e n t i a t i o n trends which i s most c h a r a c t e r i s t i c of mineralized intrusions. was  un-  This suggests that the Guichon Creek magma  not p a r t i c u l a r l y r i c h i n Cu, as t h i s should be r e f l e c t e d by  increasing Cu contents with increasing d i f f e r e n t i a t i o n . (6)  Close relationships between metal values and degree of  f r a c t i o n a t i o n emphasize- the need f o r assigning d i f f e r e n t background values to each intrusive unit during geochemical  exploration,  (?) Petrochemical v a r i a t i o n diagrams can be useful i n identi f y i n g intrusive units that are most d i f f e r e n t i a t e d and  capable  of being genetically and s p a t i a l l y associated with mineral deposits.  "CHAPTER SIX 'METAL DISPERSION IN BEDROCK AROUND MINERALIZATION  148  INTRODUCTION This section of the study reports on the nature, extent and applications of epigenetic dispersion patterns around Cu mineralization i n the Highland Valley.  Four major porphyry-type  deposits (Bethlehem-JA, Valley Copper, Lornex and Highmont) and a small vein (Skeena) were investigated.  More than 1300  samples  c o l l e c t e d from background and mineralized areas were analyzed f o r approximately 25 trace and majorelements. plans are presented i n the Appendix.  Sample locations and  At Valley Copper and Bethlehem-  JA, analyses were obtained from samples collected from three l e v e l s . Except where metal contents are obviously d i f f e r e n t f o r the three l e v e l s , r e s u l t s are only presented f o r one l e v e l t o avoid d u p l i c a t i o n . At Lornex  and Highmont, geochemical data are presented f o r surface  and d r i l l c o r e samples, whereas at Skeena only r e s u l t s from d r i l l cores are documented. Geochemical patterns are examined i n r e l a t i o n to primary l i t h o l o g y , hydrothermal a l t e r a t i o n and mineralization, using major element data as indices where applicable.  Except at Lornex, Pb, Ag,  N i , Cd, Sn, W and B i l e v e l s are generally below t h e i r detection l i m i t s and are therefore not discussed further, DATA HANDLING A l l a n a l y t i c a l data were computer-coded and  histograms  f o r a l l elements were prepared using a computer program (GHIST) provided by Dr, W.K.  Fletcher.  Means, standard deviations and other  149  statistical parameters are obtained with the histograms. Cumulative probability plots were prepared for most elements using a computer program (PROB) provided by Dr. A.J. Sinclair.  The nature of fre-  quency distribution patterns for a l l elements was determined from probability plots and verified by the Chi-square test for normality. Preliminary "Calcomp" plots of element distribution were prepared by computer.  Using transparent overlays, geochemical maps  were prepared by manual contouring where smooth trends are evident. However, i f metal distribution i s erratic, discrete symbols are used.  The choice of contour intervals was based on probability  plots as described by Sinclair (1974).  A l l geochemical maps were  transfered from overlays to base maps. Relationships among metal distributions were examined by factor analysis.  R-mode factor analysis uses a measure of simil-  arity among a l l pairs of variables to extract linear combinations which are termed "factors", of some or a l l of these variables. Standard programs (FAN) available at the Computing Centre, UBC were used to carry out the R-mode analysis. distributions were standardized (X = 0 ;  Prior to analysis, a l l metal s = l ) to prevent bias  arising from variations of concentration ranges f o r elements, i n estimating factor loadings.  Q-mode analysis was also used, but  results were similar to those of R-mode, and are therefore not discussed.  :  150  RESULTS BETHLEHEM-JA Means, standard deviations and ranges of metal concentrations are recorded i n Tables XXIV and XXV'., and Figs. Al - A27. Because of similarity i n distribution patterns, only results f o r the 2800 level are discussed. (a) Geochemical Patterns Related to Primary Lithology Rocks of the Guichon  =  Phase in the eastern part of  the property are characterized by enhanced levels of Zn, Mn, T i , V and Co compared to the more f e l s i c rocks of the Bethlehem Phase i n the west.  Lowest concentrations are encountered in rocks of the  JA porphyry i n the central portion of the property (Figs. A l - A4). Table XXV compares the means and ranges of these elements in the lithologic units.  A student t-test suggests that the Guichon Phase  i s significantly different from the Bethlehem Phase in Zn, T i , V, Co and MgO at the .05 confidence level. Variations i n Zn, Mn, V, T i and Co are strongly controlled by obvious variations i n the amounts of ferro-magnesian minerals present i n the rock units.  This i s reflected in the distribution  of MgO and Fe 0^ (Figs. A5 and A14) which are highest in the Guichon 2  Phase and lowest in the f e l s i c porphyry.  In contrast SiOg levels are  relatively enriched in the porphyry (Fig. A6).  Because of similarity  i n ionic properties,.Zn, V, T i , Mn, and Co generally substitute f o r Mg and Fe i n crystal lattices (Goldschimdt, 1954). A plot of Zn  151  TABLE XXIV;  Means, d e v i a t i o n s and ranges o f t r a c e elements a t Bethlehem  J-A (Values i n ppm except where i n d i c a t e d )  BETHLEHEM JA Number o f samples  Elements Cu  Sulphide Cu  3*  Sulphide  Analytical Technique AA  (58) Sub o u t crop l e v e l  (54) 2800 l e v e l  (48) 2400 l e v e l  1164 3.7 316-4289  1070 3.7 290-3950  1296 3.4 386-4349  AA  1234 4.1 305-4977  AA  0.62 0.45 0.17-1.07  Fe  Mo  ES  3 4.9 0.7-16  5 5.4 0.8-24  6 6.3 1-40  Ag  AA  0.12 2.2 0.05-0.26  0.12 2.1 .05-0.24  0.11 1.7 0.06-0.19  Zn  AA  19 1.7 11-32  18 1.6 11-29  16 1.6 10-25  Mn  AA  150 1.6 96-244  157 1.6 98-250  135 1.6 82-222  TABLE XXIV:  (cont.) BETHLEHEM JA Number o f samples 0  Elements  1  Co  V  (58) Sub o u t crop" l e v e l  (54) 2800 l e v e l  (48) 2400 l e v e l  AA  7 1.6 4- 11  7 1.7 4.-12  6 1.8 3-10  ES  40 1.5 26-62  41 1.5 27-61  38 1.7 22-67  1159 1.6 738-1820  1144 1.8 747-1752  1086 1.6 660-1788  Analytical Technique  ' Ti  ES  * S  Hg  XRF  0.39 4.2 0.09-1.65  AA  7 4.8 1.4-34  B  ES  Cl  ISE  H 0-Ex. Cl  ISE  F  ISE  2  10 1.9 5- 19  9 2.0 5-19 254 1.6 156-414  ,  6 2.1 3-13 216 1.8 118-395  10 1.7 5-19  153  TABLE XXIV:  (cont.) BETHLEHEM JA Number o f samples  Elements  Analytical Technique  (58) Sub o u t crop l e v e l  (54) 2800 l e v e l  H„0-Ex F  ISE  7 1.5 5-11  Rb  SRF  50 1.4 36-71  Sr  XRF  579 1.6 371-902  Ba  ES  AA  2.82 0.86 1.96-3.68  MgO  AA  1.40 0.62 0.78-2.03  AA  3.31 1.19 2.12-4.50  AA  4.27 1.39 2.88-5. 67  K 0  AA  1.91 0.97 0.94-2.88  Si02  XRF  62.34 3.40 58.94-65.74  T o t a l Fe as Fe203  Na20  2*  2  1 2 3 4  490 1.3 371-645  CaO  2*  2*  493 1.4 358-679  HNO3-HCIO4 d i g e s t i o n Total digestion KCIO3-HCI d i g e s t i o n Geometric Means except where i n d i c a t e d R=Range = Mean + 1 s t a n d a r d d e v i a t i o n  * * ** AA ES XRF  (48) 2400 l e v e l  442 1.5 289-67*  V a l u e s i n weight p e r c e n t A r i t h m e t i c mean V a l u e s i n p a r t s per b i l l i o n Atomic A b s o r p t i o n E m i s s i o n Spectropgraphy X-ray f l u o r e s c e n c e  ISE I o n - s e l e c t i v e e l e c t r o d e s  XXVt  15^  Keans and. ^ranges of some metal 'concentrations i n principal l i t h o l o g i c units, Bethlehem JA 2800 l e v e l . Guichon Phase  Ho. of samples 1*  CaO  •(2*)  (25)  3.12  2.78  (2.43 - 3 . 8 3 ) 1*  1* 2°  1.11  Ka 0 2  1*  2.84 (2.01 - 3 . 6 8 )  4.42  4.25  (2.94 - 5 . 8 9 )  (3.02 - 5.48)  1.80  1.81  (1.20 - 2.40) i  (0.?l - i . 5 i )  4.26  3  (3.30 - 5 . 2 3 ) 1*  (1.96 - 3.59)  1.91  HgO  (1.52 - 2 . 3 0 ) F e  Bethlehem Phase  Si0  (0.76 - 2 . 8 5 )  61.32  2  62.38  (58.79 - 63.84) Ti  (59.59 - 6 5 . I 6 )  1426  (5) 1.51  (663 - 1604)  •  0.89 .  (0.28 - 2 . 0 6 ) 1.72 (0.99 - 2.43) 3.69 (1.46 - 5 . 9 3 ) 3.31 (2.19 - 4.42) 67.40 (60.46 - 74.34) 769 (551 - 1073)  24  Zn  9  (17 - 33) i **  (11 - 25)  183  tin  '  (0.79 - 2 . 2 3 )  IO32  (1052 - 1933) 1**  Porphyry  (4 - 17)  145  (123 - 273)  (90  - 235)  123 (70 - 218)  53  37  26  (42 - 67)  (25 - 53)  (15 - 4 4 ) '  484  474  500 (382 - 655)  (357 - 655)  (423 - 529)  1*# Go  'Atomic absorption; I'fean - 1 standard  9  6  2  (5 - 15)  (3-12)  (1-4)  Emission  spectrography;  ^X-ray fluore;  deviation;  * Arithmetic mean and values i n wt, ,S  * * Geometric mean and values ln. p.p.  155  60Y  r ='0.8 n = 54  9  40[  ©  ®  20[  Zn (p.p.m.)  10F  0  V V  m B  1  FIGURE 39:  Wt % MgO  «  Guichon  v  Bethlehem  a  Porphyry  2  Relationship between Zinc and Magnesium contents of rocks, Bethlehem JA 2800 Level  156 TABLE XXVIi  Correlation natrlx of trace and major element content*, Bcthlehom-JA, 2300 level.  Cu  B .  Hn  Zn  Cu  .9995*  Zn  -.1730'*  1.00060  Kn  -.08821  .70569  .17534  -.08741  .26099  1.00312 •  -.02395  .37407  .23664  .00294 '  .06393  .59796  .38553  -.01200  3• Ti V  . Ho  .24779  -.42504  -.21650  • 3a  .28497  .17725  .20064  Rb  .39669  -.25715-  -.17821  Sr 310  2  Sulphur  Ko  V  • Tl  .99950.  1.00266  .41546.  .73945  1.00072  .02325 ''  -.12000  -.02377  .08678 .  -.27188  - .40102  .14047  -.44377  -.02448  -.46823  -.37635  -.06268  -.21723  -.57306  .12143  - . 3 366  .37856  — .10216  -.22540  '.03114  .14723  .28063  .19499  -.00698  -.41813  -.43877  .11914  .09174  .03507  . .21814  .16 06  .11912  -.11408  -.20008  .00269  • -.08649  .00461  .02946  .33724  .24848  .14132  ' .15053  .30901  .37868  Cab  -.28405  .49951  .37657  -.27521  MgO  • -.27303  .81286  .57275  -.17222  -.10600  .69187  .40099  -.05521  -.55648  .28908  .22334 '  -.25600  .42838  -.38177  -.16425  Sr  sio  Rb  .33321  2  • Rb  .99331  Sr  -.74479  1.00016  2  .01898  - .10320  1.00041  Sulphur  .34663  -.36924  -.25455  Hg  .43567  -.515S7  Cl  .16246  .00430  F  -.01779  C-aO •  2°  3  .50752  .72904  -.37592  .10495  .46693  • .68195  -.38210  ,27928  .03967  - 33053  -.17246  -.38265  .22188  .32358  F  GaO  '. -.02849 ' -.33699  "•'  Hg  Cl  ?  .'. .9.9S70 .27078  .99890  . .07752  -.35036  .10521  -.13684  . .O8307  .99993  -.64840  .57978  -.50424  -.18517 •  -.37364  -.O6558  .05099  1.00125  -.24205  .45685  -.51692  -.13165  -.40320  .22631  .56958  .24190  -.54686  .30893'  -.16539  -.04919  .12946  .49933  -.39741  .54661  -.08889  -.44937 .  -.23561  -.13174  -.03265 •  .24064  .86388  -.86842  .08008  .31937  .51824  .07468  Fe 0 2  3  Ka0 2  K  2°  •1.00028  KgO  . .01624  .15457  KeO  Fe 0  .09509  -.22675  .99840  3  K,0  .00509  .61439,  -.16746  • -.10108  NajO  2  .06094 '  Sulphur .  .  .  .35545  1  F e  .25576 -.13303  .49496  a  Si0  .30357  ' -.31809  -.37295  2°  .99987  -.38328  -.26620 , .39906 •  -.41770  K  -.26073  .30441  .19603  2  .99786  .21502'  Hg  )-a0  • • Ba  • .70812 .33373  1.00032 -.01334  .99929  '-.16304  -.4988O  ,09960  .OCO63 '  -.07319  -.68327  157  versus MgO (Fig, 39) shows a strong positive correlation (r = 0.81), Relationships among MgO and F e ^ and T i , V, Mn, Go and Zn are shown i n Table XXVI, A l l the aforementioned trace elements show consistently weaker correlations with Fe 0^ than MgO. 2  This  relatively weak relationships are attributed to the modes of occurence of Fe, not only ln silicates but also in sulphides (pyrite, chalcopyrite and bornite).  Compared with other trace  elements, Mn shows a relatively weaker correlation with MgO and Fe 0^. 2  This i s attributed to partial hydrothermal redistribution  within the ore zone (Fig. A2). Compared with regional data, rocks of the Guichon and Bethlehem Phases within the property are obviously depleted in Zn and Mn. (b) Geochemical Patterns Related to Hydrothermal Alteration Hydrothermal alteration effects at Bethlehem-JA are associated with enrichment in KgO, Rb and Ba and to varying extent, depletion of CaO, NagO, Fe, Sr and Mn.  Results in relation to types  of alteration are summarized i n Table XVII, KgO levels generally increase from values less than l*3?o at the outer margins of the property, to values exceeding 3.7% at the core, within and north of the porphyry dyke (Fig, A7). Rb content follows K-.0, increasing from less than 40 p.p.m. at the periphery, to more than 140 p.p.m. at the core (Fig, A8).  An east-  west trending belt of enhanced K^O and Rb contents coincide with the zone of pervasive potassic alteration (Sericite-K-feldspar).  TABLE X X V I I l  "Cher.lcal v a r l a t l o n o a s s o c i a t e d w i t h t y p e s o f a l t e r a t i o n , Bothlehora-JA, 2800 l e v e l  Unaltered Bethlehem Phase  Propylitic . Zone  ArcJllle Zone  Potassic Zone  (9)  (16)  (10)  (6)  Ho. o f r.a-.plea  M e t a l Content (p.p.m.)  33  1084  2  Cu  - 195)  (11  Zn  (386  19 - 22)  Mn  16 (11 - 22)  442  205  (364 - 542) B  5  Tl  1250  Ko  2  Ba  56O  (39 - 65)  Sr '  (381 - 621)  (528 - 721)  (0.24 - 1.45  (2-9) . 2 4 6  0j  3.35 (3.11 - 3.72)  HgO  4.09 (3.08 - 5.09) .  (1.10 - 1.63)  (1.51 - 2.42)  4.05  NajO  (3.86 - 4.90) KjO  SIC,  (8-214)  (171 - 458)  (2.02 - 3.79)  (0.81 - I.56)  165 (75 - 366) 231 (81 - I859)  1.86 (0.69 - 3.88) 0.74 (0.17 - I.65)  2.63 (1.63-3.83)  . 4.42  3.92  1.48 (0.64-2.32) 2.91  (3.37 - 5.48)  (2.74 - 5.11)  (1.78 - 4.05)  1.77  . 1.&2  3.64  (1.17 - 2.37)  66.04 (65.30  (1-44)  1.19  3.17  1.63 (1.32 - 2.40)  (0.07 - 1.99) 41  (2.51-3.82)  4.52  O.37  2.90  1.97  (3.07-5.21)  ( I l l - 500)  (wt. :i)  1.31  CaO  235 .  260  (196 - 394)  2  (54 - 121)  8  (169 - 426)  278  K e t a l Content  81  268  (161 - 375)  ?e  (322 - 980)  0.59" " .  4  Cl  •  617  (0.05 - 0.54)  F  562  (35 - 63)  686  .  (1 - 90)  47  0.15  **Hg  10  487  (570 - 828)  *s  (11 - 56)  (3 - 32)  (38 - 65)  693  (33 - 49)  (1 - 13)  41  (580 - 829)  (429 - 1308) 25  9  (398 - 649)  (34 -. 80)  748  40  4  508  43  14 (5 - 39)  (916 - 1184)  50  (500 - 800) Rb  133 (54 - 324)  1041  (977 - 1851)  - 12217)  10  10 (4 - 24)  1345  (40 - 60)  (323  (4 - 24)  (97 - 176)  8 (5 - 15)  50  .  130  (147 - 287)  (1000 - 1500)  1926  (471 - 455?)  25  2  V  - 3044)  (1? - 38)  3  (16  1466  61.05  (1.10 - 2.14)  (2.28 - 5.39)  62.17  - 66.84).- (58.42 - 63.69) (60.88 - 63.47)  65. 03.  (57.65 - 72.50)  Values p r e s e n t e d as e o o m o t r i c moans and r a n p o s , e x c e p t f o r m a j o r olemonts. * V a l u o s I n wt.-; Values l n p.p.b.  1-F-HC10, d l R o n t t o n ( T c t a l )  2  1  -"Aqun-roplii d l p e r . t l o n (~:abec, 1970J  159  Ba, to some extent follows 1^0, although the zone of enrichment i s confined to a narrow central sector of the orebody (Fig. A9). GaO, Sr and NagO values show trends that are the reverse of IC>0 and Rb distribution. Enhanced levels occur at the periphery of the property and decrease progressively  inwards (Figs. A10, A l l  and A13). Lowest concentrations occur at the centre of the property coinciding i n part with the porphyry dyke and i n part with zone of intense potassic alteration and metallization.  Distribution of  Rb/Sr and Ba/Sr ratios are similar to those of Rb and Ba respectively, in that ratios increase progressively from the outer margins to the core (Figs. A12a and A12b). ^2°3  2111(1  a  r  e t  o  s o m e  e x t e n t  depleted  within the ore zone reflecting leaching of these elements during formation of potassic and a r g i l l i c alteration zones (Figs. A14 and A2). Distribution of anomalous Rb, Ba and Sr i s strongly influenced by the type and intensity of wall-rock alteration as reflected by abundances of KgO and GaO respectively (Figs. 40 and 41).  High Rb and Ba levels are associated with a zone enriched in  K-feldspar and sericite (Fig, 11), whereas at the outer margins, where propylitic minerals are dominant, Rb and, to a lesser extent, Ba levels are relatively low.  This relationship i s amply demon-  strated by the strong positive correlation between K^O and Rb (r = 0,86) (Fig, 40), and a relatively weaker but significant correlation between K^O and Ba (r = 0,33).  These correlations are  consistent with the tendency for Rb and, to a lesser extent, Ba to substitute for K in lattices of a l k a l i feldspars.  The relationship  160  1 5 0  r = 0.86 n = 54  Rb (p.p.m.)  iool 8 o  * 5 0  20'  I  2  3  4  K 0 (wt %)  s 5  A 6  2  FIGURE 40:  P l o t ^ R u b i d i u m versus Potassium.Bethlehem JA, r = 0.58 n = 54  e  Sr  ,  soo  ©9 _ 0  9 9  9 9  (P.p.m.)  FIGURE .41:  CaO (wt %) Plot of Strontium versus Calcium, Bethlehem JA  %] 2800'ilveT :  161  between Sr and CaO (r = 0,58) is also consistent with their geochemical affinity. (c) geochemical Patterns Related to Mineralization (i) Distribution of Ore Elements (Cu, Fe, Mo, S) Copper. Cumulative log probability plot of Cu in 160 samples indicates the presence of two populations (Fig. 42);  a lower  population (B) representing 1% of the data, and an upper population (A) comprising 87% • Mean values for populations B and A are 126 and 1410 p.p.m. respectively. Compared with the regional data of Brabec (1970)» populations A and B are both 'high-copper' population. Spatial distribution of population B is very erratic, whereas population A is confined to a broad inner zone of the property. The significance of population B is not certain, whereas population A represents 'ore'. Despite the erratic distribution of Cu, values exceeding 2000 p.p.m. are confined mainly to the ore zone at the 2800 and 2400 levels (Figs. Al6 and Al?). At the Suboutcrop level, effects of oxidation and enrichment might account for the scattered occurrence of anomalous values outside the ore zone (Fig. A15). As anticipated,: sulphide-held Cu (KC10^-HC1 extraction) shows a similar distribution as HNO-j-HClO^ extractable Cu (Fig. A18). Sulphide-held Fei  Enhanced values of sulphide-held Fe ( >  0.75%)  are confined to an elongated belt extending from the eastern periphery of the property to the central part of the orebody (Fig.  163  A19).  This corresponds to the area where pyrite and chal-  copyrite are most abundant. A comparison with the distribution map of total Fe 0^ (Fig. Alk) isolates the lithological variability 2  which results i n high Fe contents i n Guichon rocks to the east of the mineralization. Molybdenum:  Mo dispersion i s erratic.  Enhanced levels ( > 100  p.p.m.) occur at the southern fringe of the orebody, coinciding with the low-grade core on the porphyry dyke (Fig. A20). Elsewhere, values are generally less than 10 p.p.m. Distribution of Mo i s consistent with metal zoning patterns l n which molybdenite i s confined to the central zone (Fig. Ik), The erratic behaviour of Mo is attributed to i t s mode of occurrence as molybdenite within tiny quartz veinlets. Sulphur:  S distribution generally increases from less than 0,1%  at the periphery to more than k% i n the ore zone (Fig. A2l). Regional background content i s less than 0,0k%, Maximum concentrations are attained i n the orebody along the Bethlehem-Guichon contact.  This coincides with the distributioni;.of sulphide-held Fe.  Since chalcopyrite contains more S than bornite, the distribution of high S values i s consistent with sulphide zoning patterns described i n Chapter 3 (Fig. Ik), S shows significant correlations with Cu (r = 0.38), Fe (r = 0.31) and Mo (r = 0.28) ( i i ) Distribution of Pathfinder Elements (Hg, B, Cl, F) Hg distribution defines a broad zone of anomalous values  164  (> 40 p.p.b.) at the centre of the property coinciding in part, with the zone of mineralization and intense potassic alteration. The periphery of the property is characterized "by background concentrations, generally less than 10 p.p.b, (Fig. A22). B dispersion i s extremely erratic, although 2 samples with values exceeding 40 p.p.m. occur at the fringes of the ore zone (Fig. A23).  There appears to be a subtle effect of rock composition  on B content in that most of the high values ( > 1 9 p.p.m.) occur in rocks of Guichon Phase in the eastern part of the property. Gl abundance ranges from 32 to 640 p.p.m. and average 256 p.p.m, (Table XXIV). Values progressively increase from less than 200 p.p.m. at the periphery to more than 500 p.p.m. at the centre of the property (Fig. A24).  An east-west-trending belt of  anomalous Cl (>400 p.p.m.^ generally coincides with the orebody. Distribution of water-leachable Cl differs in that enhanced values ( > 1 3 p.p.m,) are only well developed along the southern half of the ore zone (Fig. A25).  Since Cl occurs predominantly as chloride in  fluid inclusions, i t is most logical to presume that enhanced Cl levels in the ore zone are associated with abundant fluid inclusions. Compared with regional data, Cl appears to be depleted in Guichon rocks at the eastern periphery of the deposit. Water-leachable Cl shows a relatively weak but significant positive correlation with total Cl (r = 0.45) (Fig, 4 3 ) . Anomalous F levels (> 395 p.p.m.) are confined to two small areas within the centre and western extremity of the orebody (Fig. A 2 6 ) , With the exception of the two anomalies, values  165  30h  ®  r = 0.45 n = .54  ©  ®  © ©  cu <t! +-> (J  <D  S_ +J X  ® e @  LU I  oC M  © ©  ©  i  10  FIGURE 43:  i_  100  ©  e  ©  -J 1000  Total Cl (p.p.m.) Relationship between t o t a l and water-extractable Chlorine in rocks, Bethlehem-Ja 2800 Level  166  exceeding 216 p.p.m. occur predominantly in Guichon Phase rocks. Distribution of water-extractable F i s very erratic (Fig. A27) and shows no obvious correlation with total F (r = -0.l8). Relationships between Cu and potential pathfinder elements are summarized in Table XXVIII. No obvious correlation i s apparent between Cu and Hg, B, Gl or F.  However, there i s positive relation-  ship between KgO and Hg, B and Cu.  Rb, Ba and Sr, which are also  pathfinders, show only weak correlation with Cu, but are strongly correlated with KgO.  The lack of correlation between Cu and volatile  elements i s probably related to the erratic distribution of Cu sulphides i n fracture-fillings and as disseminations.  In contrast,  KgO i s associated with pervasive development of potassic minerals within and beyond the ore zone.  In view of the close spatial and  temporal relationships between potassic alteration and metallization, a correlation between K^O and pathfinder elements also reflects an association with mineralization, albeit indirect. ( ) R-mode Factor Analysis d  Results of R-mode analysis of 20 variables in 54 samples from the 2800 level are summarized in Tables XXLX and XXX Figs. A28 to A 3 1 .  and  Element associations characteristic of 3-,  / 4-,  and 5- factor models are tabulated in Table XXIX. These models account for 58, 66 and ?2% of total data variance respectively. Apart from the discrete 'Cl factor', the 5-factor model i s not appreciably different from the 4-factor model. On the basis of geology, mineralization and hydrothermal effects, a 4-factor model i s considered adequate. Although variability in F and Cl data i s largely unaccounted for (Table XXX).  TABLE XXVIIls  Relationships among copper, potassium and potential pathfinder.elements, Bethlehem JA, 2800 l e v e l  Variables  Correlation Coefficient (r)  Hg - Cu  0.20  B - Cu  0.18  Cl - Cu  0.12  F - Cu  0.03  Rb - Cu  0.40  Sr - Cu  -0.32  Ba - Cu  0.29  Cu - K  0.43  Hg - K  0.52  B - K  0.33  Rb - K  0.86  Sr - K  -0.87  Ba - K  0.32  significant at .05 confidence l e v e l significant at .01 confidence, l e v e l  TABLE XXIX:  Element a s s o c i a t i o n s . o f d i f f e r e n t f a c t o r models, trace and major element content of rocks, Bethlehem-JA,  2600,level  F a c t o r Model  Factor  V  Fe  Fe  Zn  Zn  Mg  Mg  Mg  Zn  V  V  Ca  Mn Ba  Ti  Kn  vs  vs  Si Si  Si Mo  K  3  Rb  Rb  X Rb  vs  Hg  Cu  Ca  S  Ti  vs Sr  K  Ca  vs  Ti Na Sr  K  Cl  B  Ba  Hg  Mo  Hg  vs  .Rb  F B Cu  Cu  S  S vs  vs  Mo  Na  Ka Cl  169  TABLE XXX: In-•mode Varimax Factor Matrix, Bethlehem JA, 2800 l e v e l .  variable  Factor 1  Factor 2  Factor 3  Factor 4  Communalitv  Cu  -0.0412  0.3199  0.1362  -0.5751  0.4533  Zn  -0.8112  -0.1915  -0.1542  0.3207  0.8213  Mn  -0.6654  -0.0833  -0.4923  0.3032  0.7839  B  -0.1044  0.4590  -0.5621  -0.3503  0.6603  Ti  -0.4841  -0/5056  -0.2039  -0,6612  0.6621  V  -0.7925  -0.4330  -0.0400  -0.2541  0.8817  Mo  0.3255  . 0.0593  -0.3324  -0.6837  0.6874  Ba  -0.4788  ©.4340  0.3423 "  O.O263  0.5354  Rb  0.0332  0.8246  0.0443  -0.305^  0.7764  Sr  -0.2084  -0.7886  0.0604  0.3798  0.8132  Si  0.7482  0.004-7  -0.1765  0.0729  0.5964  S  -0.1932  0.2084-  0.3576  -0.6619  0.6468  Hg  0.2773  0.4932  0.5318  -0.1244  0.6184  Cl  -0.0461  0.0764  O.5438  -0.1496  O.326O  F  -0.4052  0.0255  -0.1739  -0.1213  0.2098  Ca  -0.5021  -0.6447  -O.O505  0.1432  0.6908  Mg  -0.7964  -0.3Q02  -0.0621  0.2688  0.8005  Fe  -0.8287  -0.1375  0.1722  -0.0161  0.7355  Na  -0.0445  -O.3096  -0.1168  0.7108  0.6168  K  0.1172  0.8916  0.0878  -O.2655  0.8873  36  30  13  21  Eigenvalue as %  170  ( i ) Factor 1 (Fe, Zn, Mg, V, Mn vs S i ) This f a c t o r simply r e f l e c t s l i t h o l o g y .  High scores  are associated with rocks of the Guichon Phase i n the eastern portion o f the property.  In contrast, the more f e l s i c rocks of  the Bethlehem Phase and *JA Porphyry' are characterized by lower scores ( F i g . A28). ( i i ) Factor 2 (K, Rb, vs Sr, Ca, T i ) This f a c t o r which associates K and Rb r e f l e c t s potassic alteration.  High scores characterize the central part of the  property where intense and pervasive potassic a l t e r a t i o n i s prevalent ( F i g . A29).  In contrast low f a c t o r scores occur a t the  periphery where p r o p y l i t i c and a r g i l l i c a l t e r a t i o n are dominant. ( i i i ) Factor 3 ( C l , Hg vs B) This f a c t o r mainly r e f l e c t s the effects of mineralization and l i t h o l o g y on v o l a t i l e elements.  Highest scores are found i n  a broad centralszone c o i n c i d i n g with the orebody ( F i g . A30). In contrast low f a c t o r scores occur i n Guichon rocks i n the eastern part of the deposit, where B values are r e l a t i v e l y high. (iv) Factor k (Cu, S, Mo vs Na) The association of chalcophile elements, Cu and Mo with S suggests an 'ore f a c t o r * .  High scores are associated with the  ore',zone where Na i s obviously depleted.  Low scores are generally  confined t o the unmineralized periphery of the property ( F i g . A31).  171 (e) General Discussion and Summary Results indicate that variations i n the 'femic group' of elements (Mg, Zn, Mn, V, T i , Go) are related to differences in content of ferromagnesian minerals in the lithologic units. Highest values are encountered i n the more mafic rocks of Guichon Phase.  In contrast lower values and high Si are associated with  the f e l s i c porphyry and Bethlehem rocks. Fe distribution i s explicable i n terms of lithology, hydrothermal alteration and epigenetic introduction as sulphides.  K, Rb and Ba are enhanced i n  the zone of potassic alteration, whereas Ca, Na and Sr are depleted. These relationships reflect the geochemical affinity of these elements i n magmatic and hydrothermal processes. Anomalous values of* Cu, S, Hg and Cl occur in a broad central zone coinciding with the orebody.  Results of factor analysis and subjective inter-  pretation are consistent. Geochemical contrast between regional background and anomalous environments i s summarized in Table XXXI. Regional background represents fresh samples collected by Northcote  (1968).  Local background comprises a suite of samples from the periphery of the deposit, including the Bethlehem and Guichon Phases.  It i s  evident that most of the ore and potential pathfinder elements show appreciable contrast.  However, Cu, S and Hg show the best contrast  between anomalous and local background concentrations.  Contrast  between anomalous and local background i s higher for Cu and lower for S in Bethlehem than Guichon rocks reflecting the high back-  TABLE XXXI:  Comparison of mean element content and geochemical contrast in background and anomalous samples, Bethlehem-JA, 2800 l e v e l .  Regional  Regional C d  'Local BackU d(  SSZf ^(Bethlehem) ^°r . rock ° eunits) ^\ (Guichon) gX  Mineralized Z ne ( A 1  ° units) \ rock  +  No. of samples C u  (4)  (6)  ?  33  (14 )  Contrast 1  (15)  2168  32  2  5  11  5  373  448  860  5552  *  *  4 p.p.b.  16 p.p.b.  2  Contrast  (Bethlehem) i (Local Backj d  38?  6  Ko  .  Contrast (Guichon)  66  5-6  5  2.2  15  1 2  6  ,  5  4  B  Cl  5"  5  7  12  * '  .*  200  313  178  235  -  41  . 56  1.1  672  448  **2.1  1.8  F 50  Rb  43  sr  935  Ba  300  56O  421  545  Zn  27  19  24  15  Kn  422  372  1  693  Geometric means;  values i n p.p.m.  •Regional data inadequate ••Negative contrast.  152  201 '  •  2.4  2  '  k  1 , 7  1 , 6  **l,  •  ^  i'3  t  ** .8 2  1.3  -  **  **1«°2 \ '  **l-3 ' ** - ,  ? ' ''Contrast = Anomalous/Background  1  8  1  ' f 5  1 > 5  '3  1  **  *  6  1 , 3  173  ground content of Cu and low S i n Guichon rocks.  Distribution  of both Cu and S are however e r r a t i c (coefficient of variation, Cu = 1.22, and S = 1.17)  reflecting t h e i r modes of occurrence, as  f r a c t u r e - f i l l i n g s and veins. Figs. 44a and 44b are schematic diagrams showing the extent of geochemical dispersion of trace elements and d i s t r i b u t i o n of factor scores.  Compared with regional background concentrations  only Cu and S anomalies extend beyond the sampled area and the alteration aureole f o r at least 0,5km from the orebody. Anomalous values f o r other elements (Hg, Rb, Sr, Ba and Cl) are confined mainly to the orebody, or occur within the alteration envelope (Fig. 4 4 a ) . Distribution of positive scores of Factor 4 (Cu, S, Mo vs Na) i s almost as extensive as that of anomalous Cu and S, whereas positive scores of Factor 2 (K, Rb vs Ca, Ti) and Factor 3 (Hg, Cl vs B) are confined to the mineralized zone(Fig. 4 4 b ) . VALLEY COPPER Means, standard deviations and ranges of element concentrations i n the Suboutcrop, 3^00 and 3300 levels are recorded i n Table XXXII and Figs. A33- to A55«  However, because of s i m i l a r i t y  i n metal distribution at the three levels, only data f o r the 36OO l e v e l are discussed. At Valley Copper, there i s only one major host rock - Bethsaida granodiorite.  Although variations i n modal  proportions of rock constituents can s l i g h t l y influence metal concentrations, t h i s parameter cannot be documented mineralogically or by major element analysis because of alteration effects.  Hence,  sw  NE  .Limit  of sampling  Limit  of sampling  Regional Regional  Background (Bethlehem)  Background (Guichon)  3 7 2 ppm•  1422 ppm  Mn 55 ppm  I9ppm  •|27ppm  693ppm•  1935ppm  5 6 0 ppm |  Rb  43ppm |  I  V  I60ppm  1  3 0 0 ppm |  |  S—vl^Opprn^^  /  /-  ] 5 0 ppm 1 |  O S 0 8 ppm \ i  lOppb  1  Hg  | ^ \ _  |  2 2 0 0 0 ppm  2700ppm  - 3 8 0 0 ppm  2ppmf  •2 ppm  448ppm  33ppm  •373ppm  67ppm  1  j Propy1 litic  Potassic  Propylitic  1  1  B  + +  r+ +\  Porphyry >  B  FIGURE  4 4 a : Schematic  B  diagram  Bethlehem - J A , 2 8 0 0  +  :  i 1  1  B  i  |  B  ORE . ZONE  G  j  G G  +  G G  ^  G G  SCALE -•  i  1  200m  showing Level  extent  and  (^Regional  relative data  intensity  inadequate)  of  primary  halos,  FIGURE 44b:  Schematic diagram showing d i s t r i b u t i o n of f a c t o r scores, Bethlehem-JA 2800 Level  176  "TABLE XXXII;  Means, d e v i a t i o n s  and ranges o f t r a c e and major elements  a t V a l l e y Copper (Values i n ppm except where  indicated)  VALLEY COPPER :r. .  Elements Cu  Sulphide Cu  3*  Sulphide  Analytical Technique . AA  (61) Suboutcrop level 2115 3.5 607-7370  Number o f samples • (59) 3600 l e v e l  (41) 3300 l e v e l  1936 3.7 526-7120  1482 4.7 314-6996  AA  2194 3.6 619-7773  AA  0.54 0.17 0.36-0.72  Fe  Mo  ES  4 5.2 0.87-23  5 4.9 0.93-23  3 4.3 0.78-15  Ag  AA  0.18 2.9 0.06-0.54  0.21 3.1 0.07-0.68  0.23 1.7 0.07-0.77  "Zn  AA  18 1.5 12-28  19 2.3 8-45  15 1.8 8-27  Mn  AA  223 1.8 130-384  225 1.4 164-309  Co  AA  .224 1.6 139-362  177  TABLE XXXII: (cont.) VALLEY COPPER  Elements  Ti  A*  Hg  Analytical Technique  (61) Suboutcrop level  Number of samples (59) 3600 level  (41) 3300 level  ES  28 1.3 21-38  29 1.4 21-41  29 1.4 21-41  ES  948 1.5 613-1467  976 1.4 690-1377  910 1.5 619-1337  XRF  0.45 2.61 0.17-1.16  AA  2.4 2.9 0.83-7.16  ES  8 1.7 5-14  8 1.7 4-13  Cl  ISE  (GM)  240 1.4 173-333  H 0-Ex. Cl  ISE  2.3 1.8 1.3-4.3  ISE  1.392 1.4 272-564  H 0-Ex. F  ISE  5.2 1.5 3.5-7.7  Rb  XRF  59 1.2 48-73  2  2  7 1.6 4-11  178  TABLE XXXII;  (cont.) . VALLEY COPPER Number o f samples  Elements  Analytical Technique  Sr  XRF  Ba  Es  2*  (61) Suboutcrop level  (59) 3600 l e v e l 562 •1.8 304-1044  568 . 1.3 433-745  545 , 1.2 436-681  CaO  AA  1.95 0.80 1.14-2.75  2*. MgO  AA  0.42 0.11 0.31-0.53  AA  1.83 0.52 1.32-2.35  Na 0 2  AA  2.78 1.19 1.60-3.96  K 0  AA  2.78 0.71 . 2.07-2.50  XRF  67.01 4.14 62.87-71.15  T o t a l Fe as *  F e  2*  2*  2°3  2  SiO-  1 2 3 4 * ." *  (41) .3300 l e v e l  HNO3-HCIO4 d i g e s t i o n Total digestion KCIO3-HCI d i g e s t i o n Geometric Means except where i n d i c a t e d Values i n weight p e r c e n t A r i t h m e t i c Mean Values i n p a r t s per b i l l i o n .  AA = Atomic A b s o r p t i o n ES = E m i s s i o n Spectrography XRF = X-Ray F l u o r e s c e n c e ISE = I o n - s e l e c t i v e e l e c t r o d e s R = Range (Mean + s t a n d a r d d e v i a t i o n )  584 1.4 425-803  1 7 9  geochemical dispersion i s discussed only i n relation to hydrothermal alteration and mineralization. (a) Geochemical Patterns Related to Hydrothermal Alteration Variations i n trace and major element contents are influenced "by intensity and types of alteration; a r g i l l i c a t the periphery;  weak to moderate  intense potassic/phyllic a t the centre  and northwest, and s i l i c l f i c a t i o n at the southeastern sector of the property (see Fig. 16), Metal concentrations i n relation to alteration types are summarized i n Table XXXIII, ( i ) Zn, Mn, Sr, Ba, MgO, F e 0 y 2  CaO and Na 0 decrease pro2  gressively from the outer margins where a r g i l l i c alteration (sericite-kaolinite) i s dominant, to the central zone of intense p h y l l i c alteration (Figs. A32 - A 4 l ) . The rate of metal depletion i s highest f o r Mn, Sr, Na 0 and CaO (Table XXXIIl). 2  Mn distribution  at the 3300 l e v e l i s generally more uniform than at the 3&00 l e v e l (Figs. A33 and A 3 ^ ) .  This corresponds to a decrease i n intensity  of hydrothermal alteration as the base of the orebody i s approached. Although Ba and Sr both decrease from the periphery to core of the deposit, Ba/sr ratios increase i n the same direction (Fig, A36b); 'that i s , the rate of Sr depletion Is higher than that of Ba. The s i m i l a r i t y i n geochemical behaviour of Zn, Mn, MgO, Fe 0^, Sr, 2  CaO and Na 0 at Valley Copper i s demonstrated by t h e i r significant 2  positive correlations (Table XXXIV). ( i i ) In contrast to the above elements, Rb and KjO levels increase respectively from less than 51 P»P»m. and 1,8% at the  180  TABLE XXXIII:  Chemical variations associated with types of alteration, Valley Copper  Unaltered  vBe.thsai'da-,  Phase No. of Samples Cu  (6) 19  2  (4 - 135) Zn  level  Argillic Zone  362  2  Ti  5 600  15 (10 - 20)  Mo  2  (10)  (?)  506  3869  2379  1444  (64 - 1000)  520 (500 - 700)  Rb  35 (33 - 37)  Sr  588 (550 - 627)  (2300 - 6506) (877 - 6452) (597 - 3494) 20  15  (7 - 37)  (15 - 26)  (10 - 23)  176  252  (78 - 397)  (160 - 398)  9  8  6  7  (4 - 19)  (5 - 13)  (4 - 9)  (4 - 12)  1009  1178  16  (7 - 101) 333  1015  893 24  (17 - 33) 6 (1 - 29)  Ba  Quartz-rich Zone  (12)  (400 - 700) (703 - 1136) V  Potassic Zone  (11)  (290 - 420) (218 - 508) B  Phyllic Zone  Metal Content (p. p.m.)  26  22  3  (11 - 32) Mn  36OO  556 (470 - 659) 57  173 (132 - 229)  (685 - 1504) (681 - 1495) (827 - 1677) 31  34  (21 - 44)  (24 - 50)  7  5  (1 - 33)  (2 - 13)  481  564  (389 - 594) (447 - 711) 69  (45 - 71)  (62 - 75)  641  396  (418 - 980)  (161 - 969)  (Cont. next page)  61 (46 - 76)  617 (391 - 975)  24  (17 - 33) 5 (2 - 12) 535 (446 - 541)  45 (39 - 52) 529 (420 - 665)  181 (Table XXXIII Contd)  *s  0.03  0.12  0.35  0.23  (0.13  (0.27 - 0.37) (0.04 - O.38) (0.18 - 0.68) (0.08 - 0.69) (0.08 - 0.21) 3  2  (1 - 8)  (1 - 8)  (1 - 4)  301  428  384  3  -  **Hg  -  F  (219  -  Cl  (207  - 415) 264 - 335)  (334 - 547) (257 - 573) 312 (233  - 418)  223  (186 - 276)  2 (1 - 4)  347 (236 - 510)  245 (174 _ 344)  Metal Content (wt. %) Fe 0 2  3  1.91  1.70  1.82  2.20  1.19  (1.34 - 2.30) (1.32 - 2.07) (1.28 - 2.35) (1.73 - 2.67) (0.92 - 1.46) 0.54  MgO  0.42  0.39  0.50  0.34  (0.40 - 0.82) (0.30 - 0.53) (0.28 - 0.51) (O.36 - O.65) (0.28 - 0.41) 1.66 I.85 2.08 2.66 2.83  CaO  (2.16 - 2.98) (I.67 - 3.64) (1.34 - 2.81) (1.39 - 2.30) (1.15 - 2.16) Na 0 2  4.85 (4.55 - 5.31) 1.90  2°  K  3.03  2.07  (1.24 - 4.82) (1.34 - 2.81) (1.95 - .04) 2.44  3.26  2  69.79 (68.61-70.88)  65.83  67.29  (62.98-68.68) (62.51-72.09)  * Values i n wt. % ** Values i n p.p.b. 1Means and ranges (mean / -+1 standard deviation) HF-HC10^ digestion Aqua regia digestion (Brabec, 1970)  J  3.05  3.16 (2.69 - 3.62)  2.08  (1.80 - 2.29) (1.61 - 3.27) (2.63 - 3.89) (2.12 - 4.23) (1.66 - 2.51)  sio  2  2.62  66.68  71.55  (63.82-69.53) (69.29-73.81)  182  outer margins of the property, to values exceeding 71 p.p.m. and 3*2% respectively at the central zone of intense p h y l l i c / potassic a l t e r a t i o n ( F i g , A42 and A43).  Rb/Sr r a t i o s follow  c l o s e l y Rb d i s t r i b u t i o n , although the anomalous zone i s s l i g h t l y displaced eastwards r e f l e c t i n g Sr dispersion ( F i g . A44). Dependence of Rb concentrations on K abundance i s demonstrated by a positive c o r r e l a t i o n ( r = 0.64). ( i i i ) Although enhanced S i 0  2  (>66%)  values  occur i n a  (>70%) are  broad central zone of the property, maximum values  associated with the zone of s i l i c i f i c a t i o n (barren quartz veins) towards the southeast of the deposit ( F i g . A45).  This zone i s a l s o  characterized by s l i g h t l y lower Sr, MgO, F e 0 ^ , Na 0, KgO and Rb 2  2  than background areas (Table XXXIIl). (b) Geochemical Patterns Related t o Mineralization ( i ) Ore Elements (Cu, F e , Mo, s) Goppert  (Figs. A46 - A48) A cumulative l o g p r o b a b i l i t y plot of Cu  i n 161 samples ( F i g . 45) shows that Cu d i s t r i b u t i o n comprises two populations, A and B, i n the proportion of 93 and 7% respectively; separated by a threshold value of 400 p.p.m.  Mean values f o r  populations A and B are 31^2 and 25 p.p.m. r e s p e c t i v e l y .  Popula-  t i o n B corresponds to l o c a l background, and i s s i m i l a r to the "lowcopper" population obtained by Brabec  (1970)  f o r regional data.  d i s t r i b u t i o n though not symmetric, i s confined to the periphery of the deposit.  Population A corresponds t o mineralization, and  Its  184  i s confined to the central mineralized zone (Figs. A46 - A4S). As; expected, sulphide Cu as determined by KCIO^-HCI digestion i s s i m i l a r - i n d i s t r i b u t i o n t o " t o t a l " (HNO^-HGIO^) Cu ( F i g . A49). Relationship between Cu and q u a r t z - s e r i c i t e a l t e r a t i o n i s demonstrated by p o s i t i v e c o r r e l a t i o n between Cu and K^O ( F i g . 4 6 ) , Sulphide-held Fe;  Abundance of sulphide Fe i s generally low  (< 0,9%), r e f l e c t i n g the low content o f sulphide-held Fe i n bornite (Cu^-FeS^) compared t o high content i n chalcopyrite (CuFeSg) a t Bethelehem-JA.  Values exceeding 0,5% are confined to a l i n e a r b e l t  i n the northwest where pyrite and chalcopyrite are r e l a t i v e l y abundant ( F i g . A50).  Within the ore zone, values are generally  less than 0,3%, Molybdenum8  Although Mo d i s t r i b u t i o n i s e r r a t i c , enhanced values  (>23 p.p.m.) are confined p r i n c i p a l l y t o the borders of the Cur l ch zone ( F i g . A51).  This d i s t r i b u t i o n suggests metal zoning that  has not been d i s c l o s e d by previous mineralogical studies. Sulphur:  Anomalous l e v e l s of S (> 1$) occur i n the northwest and  eastern parts of the property, where chalcopyrite and p y r i t e are more abundant ( F i g . A52), and coincide with enhanced l e v e l s of sulphide-held Fe.  (See F i g . A50).  The c e n t r a l part of the orebody,  i n which bornite predominates, i s associated with r e l a t i v e l y lower S values  (<3$).  Thus, i n general, d i s t r i b u t i o n of S i s consistent  with sulphide zoning patterns described i n Chapter 3 ( F i g . 16b).  185  r = 0.52 n = 61 100001-  • ••• • • • • •• • • ©  IOOOH  Cu p.p.m.) 100K  'Or  1 FIGURE 46:  2  3  4  .5  Relationship between Copper and Potassium at Valley Copper 3600 Level  186  ( i i ) Pathfinder Elements (Hg, B, C l , F) Hg values range from 1 to 52 p.p.b. and average 3 p.p.b. Only 6 out of 6l values exceed 7 p.p.b. (mean + 1 standard deviation), and no trends are apparent. B dispersion i s e r r a t i c , although values exceeding 11 p.p.m. are generally confined to the outer margins of the ore zone especi a l l y on the northwestern fringe (Fig. A53). Cl levels do not show appreciable variations with most values l y i n g i n the range of 200 to 330 p.p.m. However, the few erratic values exceeding 330 p.p.m. are confined mainly to the orebody (Fig. A54).  Concentrations of water-extractable C l range from  1-11 p.p.m. and average 2 p.p.m. High F values ( > 564 p.p.m.) occur p r i n c i p a l l y i n the area immediately northwest of the ore zone (Fig.  A55)»  Elsewhere F levels are less than 400 p.p.m. Water-  soluble F ranges from 2 to 11 p.p.m. and average 5 P»P#m. No trends are evident and no obvious relationship exists between water-leachable F and t o t a l F, although a weak but significant positive correlation i s apparent between water-extractable Cl and t o t a l Cl ( r = 0.32). (c) R-mode Factor Analysis Results of R-mode analysis of 17 variables i n 61 samples from the 36OO l e v e l are summarized i n Tables XXXV and XXXVI and Figs. A56 and A59» Element associations of 3-»  and 5- factor  models are compared i n Table XXXV, These models account f o r 52, 61 and 66% of t o t a l data v a r i a b i l i t y respectively.  In view of known  TABLE XXXIVi  Correlation Coefficients, Valley Copper 36OO Level (61 samples)  Cu  Zn  Kn  Ti  Cu  1.00111  Zn  -.09361  1.00026  Kn  -.39456  .33735  1.00040  Ti  .01792  .15575  -.01470  1.00237  K0  .24672  .05675  -.10567  .12393  .99541 -.04652  Ko Ba  • BA  RB  SR  .12542  .143,69  -.03094  Rb  .37740  .12089  .12647  .12232  .11787  -.27221  Sr  -.26812  -.13824  .22664  -.19647  -.01470  .03285  -.29744  1.00064  .09192  -.22783  -.70357 '  -.01000  .02269  -.20817  -i34770  -.22679  Sulphur  .31459  -.01634  .00612  -.13831  .27055  -.04437  CL  .16146  -.03333 •  -.21862  .00140  -.06280  -.13436  -.03408  -.27440  Fluorine  .23018  .09253  .09167  .11768  .11324  -.13848-  .22627  .00918  .77431 .  -.04650  .06439  .13281  .07514  .29501  -.00056  .19606  .11181  .20753  310  2  •.1W2  .  .13736  .19159  i'EC  -.13108  .43593  '.44522  .09750  .13123  .42963  .46563  .04807  .17619  .12471  .31695  .13936  -.42909  -.00011  -.22651  -.17826  .23922  -.60460  .31261  .51606  .19298  .04022  .09952  -.18691  .63246  -.08751  2  siu 2  2  Sulphur  •. .08370 . -.08456  CL  -.28130  1.00061  CL  . .24300  .-.19320  .99923  Fluorine  -.13977  .37444  -.29287  CAO  -.6061*6  MgO  -.38657  2°3 llajO 2°  F  1.00083  Sulphur  K  .26239  -.38200  2°3 ;.-a o  Fe  .99827 '  Cad  FE  510  .99903  -.59311  • .20511 • .-5547 .31720 '  -.00597  -.13923  -.13096  .32400  .99867  CAO  -.32643  .14866  .99892  -.22062 .  .20122  .28790  .99969  -.31070  .36293  .25726  .6856I  .99975  -.21901  -.03647  .07204  .05967  -.14842  .18374  .31122  -.09350 . -.04018  .33291  KCO  FE 0 2  3  CO  .99807 •  -.59373  T A 3 L S XXXVi  Element a s s o c i a t i o n s o f d i f f e r e n t f a c t o r models, V a l l e y . Copper 36OO l e v e l . FACTOR MODEL  FACTOR  >  5  fin  Ca  Ca  Fe  Mn  Kn  Ca  Sr  3  1  Kg .  vs Si  vs  Zn  Cu  Si Cu  vs Si  2  Cu  S  K .  S  Cu  Rb  K  F  F  Fe "  vs Sr  K  vs Cl  3  K  Rb  S  Rb  K  F  vs  vs  vs  Sr  Ha  Na  Sr Zn •  Cl  •  Mg  Mg  Fe  Fe  Zn Ko  5  Ti  "  189  TABLE XXXVI: Variable  Varimax Factor Matrix, Valley Copper, 36OO Level  FACTOR 1  FACTOR 2  FACTOR 3  FACTOR 4  COMMUNALITY  0.3939  -0.0249  0.7247  0.7799  O.6344  Cu  -0.4396  0.6129  Zn  0.1376  -0.0433  Mn  0.8817  -0 0974  -O.O3O8  0.2886  0.8712  Ti  -0.1100  -0.0979  0.2767  0.35^9  0.2242  Mo  -0.1179  0.4091  0.0798  0.0432  0.1895  ?  0.0731  Ba  0.0521  -0.0201  -0.4616  0.3409  0.3324  Rb  0.2005  0.2619  0.8052  0.1306  0.7742  Sr  0.4066  0.2640  -O.5078  -0.2458  0.5532  Si  -0.7828  -0.2050  -0.0799  -0.2546  0.7261  S  0.1814  0.7053  0.1172  -0.1401  0.5637  Cl  -0.2723  -0.5516  0.2?13  -0.0357  0.4533  F  0.1025  0.6063  0.1730  0.1132  0.4208  Ca  0.8951  0.300  -0.0395  0.0028  0.8035  Mg  0.3378  0.2216  -0.1445  0.7045  0.6804  Fe  O.366I  0.5153  -0.0237  O.6328  0.8006  Na  0.0186  -0.1440  -0.8426  0.0523  0.7337  K  -0.0686  0.4855  0.6273  0.1965  0.6726  30  24  Eigenvalue i n %  26  20  190  geologic and raineralogic evidence, a k- factor model i s considered appropriate, although i t does not account f o r a large proportion of the variance i n Mo, T i and Ba (Table XXXVI). ( i ) Factor 1 (Ca, Mn, Sr vs S i , Cu) This factor reflects a r g i l l i c alteration.  High factor  scores coincide with the outer margins of the property which are r e l a t i v e l y unmineralized and characterized by weak to moderate pervasive a r g i l l i c alteration.  In contrast, low scores occur i n the  central zone of intense quartz-sericite alteration and metallization (Fig.  A56).  ( i i ) Factor 2 (S, Cu, F, Fe, K vs Cl) Association of Cu and S suggests an "ore factor".  However,  high factor scores are concentrated along a curved belt immediately north and northwest, and on the fringes of the orebody, where a chalcopyrite/pyrite zone i n conjunction with K-feldspar alteration i s dominant (see Figs. 16, A50 and A52).  Low scores are found i n the  centre of the orebody where bornite i s the dominant sulphide, and in the barren quartz zone to the southeast  (A57).  ( i i i ) Factor 3 (Rh, K ys Na, Sr) This factor reflects potassic alteration.  High scores  are confined to the central and northwest parts of the deposit (Fig. A58).  In contrast, low scores occur at the outer margins  especially i n the west, and i n the southeast where barren quartz veins are conspicuously developed.  191 (iv) Factor 4 (Zn, Mg, Fe) The significance of t h i s factor which associates the femic elements (Zn, Mg, Fe) i s not well understood.  High scores occur  along a l i n e a r belt Immediately north and within the ore zone, whereas low scores are confined to the centre and southeast. Distribution of this factor closely follows that of Zn (Fig. A32). However, i t s association with Mg and Fe most probably reflects the distribution of secondary b i o t i t e which i s known to occur i n the northern fringes of the orebody, although i t s detailed distribution has not been documented. (d) General Discussion and Summary Results indicate that Zn, Mn, Sr, Ba, Mg, Fe, Ca and Na generally decrease from the outer margins to core of intense alteration and metallization.  In contrast, Rb and K are enriched  i n the central zone of potassic/phyllic alteration.  Enhanced S i and  impoverished Sr, Ba, Mg, Fe, Na, K and Rb are characteristic of the s i l i c i f i e d zone i n the southeast.  The apparent depletion of 'femic'  and lithophile elements i n zones of intense p h y l l i c and a r g i l l i c alteration i s attributed to the breakdown of b i o t i t e and plagioclase into s e r i c i t e and kaolinite.  The base elements are leached and  transferred to the outer margins of the deposits by outward-migrating solutions. Maximum levels of Cu are associated with the central zone of intense mineralization, whereas high S and sulphide-selective Fe are confined to the northwest rim of the deposit where pyrite and  192  TABLE XXXVIIs  Comparison of mean element content i n background and mineralized samples , Valley Copper 36OO l e v e l .  No. of Samples  Regional Local Background Background (Bethsaida) (Bethsaida) (9)  265  4580  Mo  2  7  9  322  830  *  B  3 p.p.b.  *  F  3 .^©ntrast.  -^'Contrast  (Regional)  (Local)  241  2930  17  4.5  1.3  9  3.5  -  3 p.p.o.,?  1.4  7  9  5  Cl  1 **  1.3  265  288  -  1.1  310  413  -  1.3  1.9  1.3  Rb  35  54  66  Sr  588  642  462  **  1.3  **  1.4  Ba  520  556  514  **  1.0  **  1.1  Zn  22  21  14  **  1.6  **  1.5  Mn  362  337  155  **  2.3  **  2.1  1.90  2.29  3.09  Na 0  4.35  3.28  2.03  **  2.1  **  1.6  CaO  2.83  2.47  1.42  **  2.0  **  1.7  1.91  1.68  I.85  **  1.0  %o 2  2  (12)  19  Hg  2  (10)  Cu  S  2  Mineralized Zone  Fe 0 2  3  1.6  1.3  1.0  * Regional data inadequate ** Negative contrast Geometric means and values i n p.p.m. except where indicated. 1  2  Arithmetic means and values i n wt. %,  ^ Contrast = Anomalous/Background  193 chalcopyrite are most abundant. Contrary to expectations, Hg and Cl do not show anomalous patterns at Valley Copper. B and F are generally e r r a t i c , although high values occur within the ore zone. Results of factor analysis are consistent with subjective interpretations of metal associations i n relation to geologic processes. Geochemical contrast between background and anomalous samples i s summarized i n Table XXXVII, Regional background comprises fresh Bethsaida samples collected by Northcote (1968), Local background consists of samples at the periphery of the deposit:. Relative to regional and l o c a l background, Cu and S show the best contrast, whereas B and Hg show no contrast. Relatively pronounced negative contrast i s shown by Sr, Na and Ca, and positive contrast f o r Rb and K,  Although, both Cu and S are generally e r r a t i c , Cu  shows a greater variation as reflected by t h e i r coefficients of variation, (Cu = 1,12;  S = 0,7?). Compared with regional back-  ground data, i t i s apparent that halos of Cu and S extend beyond the sample area and at least 0,5 km from the ore zone on a l l sides; and also extend beyond the alteration aureole.  In contrast the  halos of the other elements are of limited extent (Fig,  47a).  Negative scores of Factors 1 (Ca, Mn, Sr vs S i , Cu), 2 (S, Cr, F, Fe, K vs Cl) and positive scores of Factor 3 (RD, K vs Na, Sr) extend beyond the ore zone and as f a r as the periphery of the a l t e r ation envelope (Fig,  47b)  LORNEX Results f o r surface and d r i l l - c o r e samples are presented  WEST  EAST |  Limit of sampling  Regional Background  Limit of sampling  362 ppm  22 ppm  588 ppm  520 ppm  35ppm  Hg  Sulfide Fe  1800 ppm  2ppm  •322ppm 8990ppm  !  Phyllic  Argillic  Bethsaida  i  SCALE  0  ORE  Phase  Bethsaida Phase  ZONE 1  200m  FIGURE 47a •. Schematic Valley  Argillic  diagram  Copper  showing  3600  Level  extent  and relative  (* Regional  data  intensity  of  inadequate)  primary  halos,  l9ppm  E  Factor 4  I—*  FIGURE 47b:  Schematic diagram showing d i s t r i b u t i o n of f a c t o r scores, Valley'Copper, 3600 l e v e l .  196 TA3LE XXXVIII:  *Means and ranges of trace and major elements, Lornex property.  Surface Samples  Subsurface Samples  A l l Samples  (103)  (85)  (188)  No. of samples  Metal Content (p.p.m) .  l&  Cu (i±  Zn  Sr  10  16  8  (5-24)  (8 -'31) .  573  518  458  (333 - 806)  (283 - 742) 1138  780  925 (570 - 1501)  (783 - 1653)  31  33  (18 - 43)  (19 - 49)  (18-59)  3  9  3  (2-51)  (1-8) Ba  (116 - .534)  (91 - 742)  28  Mo  249  260  240  (473 - 1284) V  (12 - 64)  (12 - 105)  (39^ - 835) Ti  27  35  23  (4 - 16) .  (10- 3200)  (75 - 12655)  _ ^56)  (160 - 359) B -  180  978 '  (lit-- 36) Kn  •  (1 - 19)  420  461 (307 - 694)  443  (244 - 722)  (275 - 711)  Metal Content (wt. %) , Fe  2°3  I.85 (1.16 - 2.54)  CaO  2.99 (2.29 - 3.69)  Na^O  3.71 (2.98 - 4.44) 1.47 (0.92 - 2.01)  .1.85  I.85 (0.74 - 2.96)  (0.95 - 2.75)  2.27 (0.90 - 3.64) - 2.49 (1.38 - 3.6O) 1.95 . (1.34 - 2.55)  * Geometric means, except f o r major elements.  2.66 (I.65 - 3.73) 3.16 (2.06 - 4.26) 1.68 (1.06 - 2.31)  197 i n Figs. A57 to A?l and Table XXXVIII.  Apparently, half of the  surface samples are fresh and unmineralized, whereas'the remainder (51  samples) are weakly altered samples collected from the peri-  phery of the Lornex orebody and from the sub-economic deposit (Discovery Zone) south of the main orebody (see Appendix).  The  l a t t e r group of samples are designated "mineralized surface" samples, i n contrast to mineralized subsurface ( d r i l l - c o r e ) samples. B, Sr, T i , V, Mo and Ba were determined by semi-quantitative;.emission spectrography;  Cu, Zn, Mn, Ag, Pb, Ca, Cd and Ni by atomic absorp-  tion (HNO^ - HCIO^ digestion);  and Ca, Fe, Na and K by atomic  absorption analysis of HF - HCIO^ digests, using the 'rapid teflon tube* procedure.  Sample locations and plans are presented i n the  Appendix. (a) Geochemical Patterns Related to Lithology Variations i n T i , V, F e ^ , CaO, Ba, Na 0 and KgO i n 2  unmineralized surface samples at Lornex are principally related to variations i n abundance of ferromagnesian minerals and feldspars. Rocks of the Skeena Phase i n the eastern part of the property are enhanced i n T i , V, F e ^ and CaO (Table XXXIX), which reflects the greater abundance of femic minerals and the more calcic plagioclase composition.  Ln contrast, rocks of the Bethsaida Phase are char-  acterized by higher concentrations of Na 0, KgO and Ba. 2  A plot of  Ba versus K^O shows a strong positive relationship (Fig. 48). However, surprisingly, Mn shows a negative correlation with F e 0 y 2  (Fig. 49).  This relationship i s attributed to the abnormally high  198  TABLE XXXIX: *Keans and ** ranges of metal concentrations i n Lithologic units, Lomex Surface (unmineralized). Skeena Phase No. of samples  Bethsaida Phase  (19)  (33)  Ketal content (p.p.m.)  13  Cu  Zn  (3 - 60)  (3 - 58)  20  20.  (15 - 26) Mn  14  (16 - 25)  172 (132 - 226)  Sr  Ti  (213 " 330)  597  606  (466 - 764)  (466 - 788}  728  533  (512 - 1036) V  266 :  (318 - 820)  33  17  (26 - 42)  (13 - 23)  428  Ba  (290 - 632)  510 (365 - 712)  Metal content (wt. %) FE  2.12  2°3  (1.46 - 2.77) CaO  3.50 (2.97 - 4.02)  M a  2  3.70  a  (3.34 - 4.05) 1.13  h°  (0.55 - 2.29)  1.47 (1.31 - 1.64) 2.68 ( 2.20 - 3.15) 4.05 (3.75 - 4.35) 1.42 (0.82 -1.82)  * Geometric means, except f o r major elements  + * Mean - standard deviation.  199  r n  500H  Mn (PPm)  V  V  V  -0.42 51  V W o  VV V vv  W V  V  s  lOOh  50L  Fe as % f e 0 2  FIGURE 49:  Manganese versus Iron in unmineralized samples, Lornex Surface.  0.63 51  1000  Ba (ppm)  V  Skeena Phase  v  Bethsaida Phase  v  v V  @  v V  500  3  © 3  v  ®  V  100  50  K0 % Plot of Barium versus Potassium in background samples, Lornex Surface. (*several samples p l o t at the same point) 2  FIGURE 48:  200  concentrations of Mn i n b i o t i t e of Bethsaida Phase (Chapter 7, Table LIX). A student t-test suggests that, at the ,05 confidence l e v e l , significant difference exists between fresh Skeena and Bethsaida Phases i n Mn, T i , V, Ba, F e ^ , CaO and Na 0, but no signif2  icant difference i n Cu, Zn, Mo, Sr and KgO. Metal concentrations i n fresh Skeena and Bethsaida within Lornex property do not d i f f e r appreciably from regional data. (b) Geochemical Patterns Related to Hydrothermal Alteration Effects of hydrothermal alteration are most evident i n d r i l l - c o r e samples which penetrate the ore zone, and to a lesser extent i n mineralized surface samples. Table XL shows the concentrations of trace and major elements i n relation to alteration types.  Zn, Mn and FegO^ levels i n surface samples are r e l a t i v e l y  enriched i n the propylitic zone at the periphery of the deposit relative to background Skeena rocks to the east (Figs.A60ib, A6lb & A62b) i n pocket). The enhanced trace-element values are attributed to substitution f o r Fe i n chlorite, epidote pyrite and siderite.that are r e l a t i v e l y abundant i n t h i s zone.  In contrast to the above  distribution, the Discovery Zone l y i n g south of the main orebody i s characterized by lower values because of the f e l s i c composition of the porphyry host rock and a r g i l l i c alteration.  The relation-  ships between Zn and Mn, and FegO^ are demonstrated by positive correlations.  (Zn and FegO^, r = 0.52? Mn and FegO^, r = 0.48),  Ba, Sr and KgO do not show systematic variations related to a l t e r ation i n surface samples.  201  TABLE XL:  *Means and **ranges of element abundances associated with alteration types, Lornex Subsurface.  Unaltered Skeena Phase  Propylitic Zone  (6)  (15)  Mo. of samples  Propy-Argillic A r g i l l i c Zone Zone (15)  Phyllic Zone  (20)  (8)  Ketal content (p.p.m.)  Cu  26  1  999  (9-45) Zn.  2  Kn  1  19 (22 - 35) 312 (250 - 340)  B  Sr  -  5  2754  (245 - 4065) (1462 - 5186)  1000 (900 - 1200)  V  Ko  22  (17 - 92)  (26 - 56)  (12 - 40)  275  201  (166 - 453)  (135 - 298)  (104 - 436)  17  30  (7 - 28)  (10 - 30)  (19 - 48)  490  432  520  252  (299 - 625)  978  (300 - 900)  1275  .35  32  36  (30 - 40)  (26 - 38)  (25 - 52)  5  8  (500 - 600)  218  (5 - 20)  (917 - 1772)  550  (12 - 32)  (116 - 451)  14  (1 - 21) Ba  23  229  (734 - 1303)  2  (2250 - 5448) (54 - 10314)  38  (625 - 680) • (298 - 807) . Ti  752  40  10  653  3501  1473  944  (1053 - 2060) (595 - 1496) 44  14  (35 - 56) 14  (3 - 22)  528  (3 - 62) 10  (35 - 56)  485  317  (38I - 732) (324 - 727)  (180 - 353)  (3 - 32) 371  (234 -  585)  (267 - 515)  Metal .content (wt. Fe 0 2  CaO  3  2.98  3.09  1.83  (2.80 - 3.47)  2.57 - 3.61  (1.31 - 2.34)  3.84  2.48  I.69  (3.73 - 3.91) (1.97 - 2.98) NagO  4.78  2.80  1.73  (1.14 - 1.85) (I.03 - 2.34) 2.60  2.83  1.79  1.68  1.06  (0.81 - 2.56) (0.83 - 4.37) (0.53 -  (4.38 -- 5.19) (1.89 - 3.71) (2.21 - 3.46) \°  1.49  2.56 (1.65  2.05  (1.30 - 1.96) (1.41 - 2.18) (I.36 - 2.74)  I.30  - 3.46) (0.1 - 2.60) 1.93  c  3.52  U;34'- 2.51) (2.76 - 4.26)  * Geometric means, except f o r major elements ** Mean i 1 standard deviation HF-HC10^ digestion:  1.60)  kqy& regia digestion (Brabec, 1970)  ^  202 In subsurface samples, Zn and FegO^ values decrease westwards from the eastern border of the orebody, and lowest values are attained i n the zone of intense a r g i l l i c , p h y l l i c and potassic alteration close to the Lomex Fault (Figs. A60 and A6l). Mn shows a s l i g h t l y different d i s t r i b u t i o n .  Lowest values are encountered i n  a central zone (Holes 8 , 9 and 1 0 ) where a r g i l l i c alteration i s prevalent (Fig. A62). Sr distribution closely follows those of CaO and NagO i n that highest values ( > 600 p.p.m, Sr, >k% CaO and > 2.8)5 Na 0) are 2  confined to Hole 1 0 where gypsum and quartz-carbonate-sulphide veins are r e l a t i v e l y abundant. Lowest values of these elements are confined to the eastern periphery of the deposit and immediately east of Lornex Fault (Figs, A63a, A63b and A64), similar to that of  K^O  p.p.m. Ba and >2.6)S  (Figs. A65a and  K^O)  A65b).  Ba distribution i s Maximum values ( >  800  occur immediately east of Lornex Fault  where K-feldspar veins are abundant, and i n Holes 8 and 9 where s e r i c i t e with muscovite i s common. (c) Geochemical Patterns Related to Lornex Fault The north-trending Lornex Fault transects the Lornex property and extends f o r more than 16 km across the Guichon Greek batholith.  Gouge zones associated with the f a u l t are up t o 1 0 0 m  wide, adjacent to the Lornex orebody. Gouge samples collected from the f a u l t were analyzed by X-ray d i f f r a c t i o n , and results indicate that the dominant minerals are quartz and s e r i c i t e .  X-ray  patterns suggest, but do not confirm, the presence of sphalerite.  203 There i s no evidence of secondary coatings of Fe and/or Mn oxides. Anomalous trace and major element patterns are associated with gouge samples from the Lornex Fault adjacent to the Lornex orebody (Table XLl).  Many elements that are not abundant within  the orebody are r e l a t i v e l y enriched along the f a u l t .  Thus Zn values  i n excess of 1000 p.p.m. are common, In contrast to values of less than 30 p.p.m. immediately west of the fault (Fig. A 6 0 ) .  Mn, Ag,  Pb, Gd, Hg and CaO, and to a lesser extent Mo, are enriched i n the f a u l t gouge (Figs. A6l, A66, A67, A68, A71 and A63).  In contrast,  Cu, Ni, Co and FegO^ do not show such enrichment. F i g . 50 shows that Hg closely follows Zn, probably i n sphalerite.  Samples collected  from the f a u l t gouge about 500m north of the orebody do not show anomalous metal concentrations, suggesting that the anomaly might be directly related to the Lornex orebody. The Lornex Fault adjacent to Lornex orebody i s unique i n the Highland Valley f o r associated anomalous metal concentrations. This fault i s a major crustal feature i n the area (Ager et a l . ,  1973)  and i t s influence on the l o c a l i z a t i o n of the Lornex and Valley Copper deposits can not be over-emphasized. (McMillan, 1971)  Structural evidence  suggests pre- and post- mineralization movements  occurred along the f a u l t .  The present locations of the two deposits  have been attributed to post-mineralization l e f t - l a t e r a l movement on the fault (Carr, 1967). This contention i s to some extent supported by the sharp truncation of geochemical anomalies by the f a u l t i n the Lornex property.  Lack of Cu enrichment along the f a u l t , suggests  204  TABLE XLI:  Metal concentrations along the Lornex Fault.  Background Samples  Lornex Fault Samples  (10)  (15)  Means  Banges  Means  Ranges  Metal content (p.p.m.) *Hg  6  4-12  145  26 - 784  Zn  20  17 - 23  449  121 - I656  Ag  .01  -  0.24  Ni  2  1-3  Fb  1  -  Go  1  Gd  1  Mn  373  243 - 573  Cu  12  8-15  27  B  9  4-18  38  22 - 63  1-2 1  0.16 - 0.35  -  1 167  57 - 490  -  1 1  5022  2-36 I858 - 13573 14 - 52  Sr  606  438 - 838  270  174 _ 417  Ti  809  583 - 1123  794  512 - 1229  V  24  18 - 32  6  2-24  Mo  2  1-2  10  4-24  Ba  682  395 - 1176  324  230 - 458  Metal content (wt. %) Fe  1.41  1.27 - 1.56  1.36  0.94 - 1.79  2.11  1.59 - 2.63  3.87  2.85 - 4.62  Na 0  3.32  2.15 - 4.50  0.72  0.5 - 1.93  K.0  1.51  1.27 - 1.75  2.48  1.87 - 3.09  2°3 CaO 2  * Values i n p.p.h. Samples immediately west of f a u l t 1  205  •  Fault Samples  O  Samples west of f a u l t  •  Samples east of f a u l t  n = 41 r = 0.89  1000  • •• 100  • •  10  o„ o  OO  . a  -  0  a  $8o  a  o  o  o 10  FIGURE 50:  ,  , 100  1000  10000  Zn (ppm) Relationship between Mercury and Zinc along Lornex Fault.  206  that anomalous metal values are not due to post-mineralization movement and crushing of sulphides within the f a u l t zone. Because of appreciable v e r t i c a l movement on the f a u l t , the present surface represents a deeply-eroded l e v e l . might represent?  On this basis, metal concentrations  ( l ) a leakage halo, suggesting that the f a u l t  served as a pathway f o r upward migrating solutions? or (2) supergene concentrations by downward migrating surface waters.  The l a t t e r  i s less l i k e l y since acid groundwaters should also have concentrated Cu and Fe as commonly characteristic of supergene enrichment i n porphyry copper deposits i n southwest U.S.A. Consequently, the anomaly along the Lornex Fault i s believed to represent a leakage halo as defined by Hawkes and Webb (1962). ( ) Geochemical Patterns Related to Mineralization d  Coppert  Cumulative probability plot of Cu i n 188 samples shows a  characteristic curved pattern suggestive of a mixture of two lognormal populations A and B i n proportion of 60 and k0% respectively (Fig. 51).  The value separating the two populations i s estimated as 75  p.p.m. The lower population  (B) with a mean value of 6 p.p.m.  represents background surface samples, especially rocks of the Bethsaida Phase. The upper population, with a mean value of 1750 p.p.m. corresponds to mineralized subsurface and surface samples. The lower and upper populations correspond to the low-copper and highcopper populations of Brabec*s (1970) regional data. Cu content of surface samples east of Lornex deposit increases from less than 21 p.p.m. i n background Skeena to enhanced  FIGURE 51:  Probabilty (cum.%)  Log p r o b a b i l i t y plot of Copper at Lornex.  208  values ranging from 80 to 2000 p.p.m. at the periphery of the orebody (Fig. A69 i n pocket). Near the Skeena Cu vein, values are generally background (3-24 p.p.m.) In contrast,, to the above d i s tribution, Bethsaida Phase rocks west of the Lornex Fault are characterized by low Cu values (< 21 p.p.m.). In subsurface samples, Cu abundance increases from less than 100 p.p.m. at the periphery of mineralization i n the east, to values exceeding 5000 p.p.m. i n the ore zone close t o the Lornex Fault (Fig. A70). Molybdenum; Except f o r a few e r r a t i c values exceeding 20 p.p.m. within the ore zone, Mo i n surface samples i s below detection l i m i t (< 2 p.p.m,). In subsurface samples, high values (>100 p.p.m.) are encountered i n Hole 10. Elsewhere, values are generally less than 10 p.p.m, (Fig, A71a). Mo shows significant positive correlations with Cu(r = 0.40) and Fe ( r = 0,41), r e f l e c t i n g t h e i r close association within the ore zone. Other Elements;  (Ti, V, B):  Enhanced Ti ( > 2000 p.p.m.) and V  (>50 p.p.m.) levels, relative to background values of less than 1000 and 30 p.p.m. respectively, are characteristic of the ore zone i n Holes 12, 10 and 9» A significant correlation between V and Ti (r = 0,45) demonstrates t h e i r covariance.  However, no overall sign-  i f i c a n t relationship exists between T i and F e ^ ^ r = 0.09), and only a weak one between V and FegO^ ( r = O.37). Nevertheless the posi t i v e relationships between Cu and V ( r = 0.49) and Cu and T i (r - 6.38) are s i g n i f i c a n t .  Enhanced levels of T i and V are believed to be  related to the occurrence of epigenetic magnetite whose occurrence  209  has been reported by McMillan (1972), although i t s detailed d i s tribution has not been documented. B content in' surface samples east of the deposit generally increases westwards from values less than 5 p.p.m. t o more than 50 p.p.m. at the periphery of the orebody (Fig. A71b, i n pocket). Maximum value (400 p.p.m.) occur i n two samples of quartz porphyry i n the Discovery Zone.  In d r i l l - c o r e samples, values ranging from  20 to 100 p.p.m. are common within the mineralized zone i n Holes  12 and 10. (e) R-mode Factor Analysis Factor analysis was applied separately to 13 elements i n 103 surface and 85 subsurface samples.  A 3-factor model that accounts  f o r 66)S of t o t a l data v a r i a b i l i t y was chosen f o r surface samples because of the apparent simplicity of metal distribution. are tabulated i n Tables XLII and XLIII. f o r surface samples.  Results  Factor maps are not provided  Element associations of 3-»  and 5- factor  models f o r subsurface samples are recorded i n Table XLIV. A 4-factor model that accounts f o r 71% of t o t a l data variance was chosen, Correlation coefficients and varimax factors matrix are recorded i n Tables XLV and XLVI. ( i ) Surface Samples Metal associations of each factor are summarized as follows: Factor 1:  B, Mo, Cu vs Na, Sr  TABLE XLIIt  Correlation coefficients, Lornex Surface (103 samples)  Zn Zn  . 1.00008  Mn  .35471  1.00171  Cu  .26211  .31128  -.14621  .33697  .24075  -.37264  B Sr  Fe  Mn  Ti  .19533  V  .34466  .0138I  Ho  .01445  .22111  Ba  .12628  .14195  CAO  .43088  -.11792  2°3  .14722  -.11821  Nag  .06946  0  ' .07878  BA  .11540  -.40059 .35875  .99603  CAO  •35643  1.00233  -.14378  .51422  2  -.01745  .10442  £,0  .57224  2  Na 0  3  B  Sr  .99973 .53366  .99982  -.47431  -.57135  .99751  .28962  .34636  .00363  .27183  .20152  .03148  .62600  .61041  -.37531  -.05715  -.23472  -.04336  -.08345  -.27365  .27002  -.29023  -.12725  .22473  -.58741  ' -.52696  .75398  .31445  .23395  -.57951  Ti  CAO  BA  Fe 0  Cu  FEgO^  .27595  NAgO •  KgO  .99848 .13803 -.06428  . 1.00018  -.51759  I.OOO35  V  Ko  1.00082 .65622  . .99727  •34175  .27803  -.09*422  -.06181  '-.27296  .24147  .45437  -.24150  .11613  •.365OI  -.23653  -.28978  -.29302  -.54069  .18253  .20167  .15968  I..OOO36  211  TABLE XLIII:  R-mode Varimax Factor Matrix, Lornex Surface (3-Factor Model)  Variable  FACTOR 1  FACTOR 2  FACTOR 3  Communal!ty  Zn  -0.0216  0-0.5992  0.2122  0.4045  Mn  0.4425  0.0024  0.4201  0.3723  Cu  0.7752  -0.1043  0.1119  0.6243  B  0.8225  0.0530  .-0.1089  0.6911  Sr  -0.7081  -0.3253  -0.3826  0.7540  Ti .  0.4454  -O.6347  -0.1378  O.6203  V  0.3296  -0.8217  -0.0736  0.7893  Mo  0.8097  -O.O387  -0.2037  0.6986  Ba  -0.2289  -O.O369  O.85I8  0.7793  Ca  -0.2963  -0.7685  0.3463  0.7984  Fe •  -0.2641  -0.6003  -0.1324  0.4477  Na  -0.8097  0.0070  -0.2897  0.7396  0.3775  -0.1292  K  Eigenvalue i n % 46  30  0.8117  24  0.8181  212  TABLE XLIV:  Metal Associations of Different Factor Models, Lornex Subsurface. Factor Model  FACTOR  1  3  4  Na  Na  K  Sr  Sr  B  2  K  K  Na  B  . B  Sr  V  V  V  Ti  Ti  Ti  Cu  Cu  Cu  i.  Mn  Mn  Mn  i  Zn  Zn  Zn  Mo  Mo  Fe  Fe  I  • I  5  Ba vs  vs  vs  mm—  Ba k  vs  vs  vs  3  vs  vs  vs  •>5  Ba  Mo  Ca  Ca  Zn  Zn Fe  TABLE XLVi  Correlation Coefficients, Lornex Subsurface (85 samples)  Zn  Cu  B  Zn  .99907  Mn  .43083  1.00010  Cu  -.06213.  -.44652  .99993  .12799  .11402  .24503  1.00088  Sr  -.03205  ; .06261  -.20071  -.47660  1.00165  Ti  -.31363  -.32695  .38287  .09894  .01410  1.00187  V  -.50424  -.49967  .48870  -.19051  .24054  .45421  1.00243  Mo  -.07721  -.22820  Ba  -.12483  .04726  .43728  B  CAO F E  Mn  2°  •.39740. •  2  KgO  -.31713  -.35403  .03305  .03526  .OO856  -.56400  -.23708  .25943  -.00753  -.13207  -.02426  -.00144  .06868  -.19019  . .14063  .04045  -.12355  .46190  -.08887  .37263  .40641  -.25491  -.16913 ''  -.23802  -.60573  .56869  .03610  .28580  . -.22924  .15909  .20910  .40040  -.47570  .03681  " -.10949  CAO  FE 0  .18976  2  3  Na 0 2  C A O  -.02891  1.00067  -25315  -.18439  1.00019  .24555  -.17574  .17867  .99979  .23106  .14711  -.18223  -.59371  2°  KgO  ;  .29072  1.00232  Na  M0  .10279  B a  2°3  V  -.I327I  B A  Fe  TI  .25080  3  Ka 0  SR  .99879  '  1.00121  -.04096  214  TABLE XLVI:  R-mode Varimax Factor Matrix, Lornex Subsurface (4 - factor Model)  FACTOR 1  FACTOR 2  FACTOR 3  FACTOR 4  Communality  Zn  -0.1371  -0.5809  0.0648  -0.6531  0.7870  Mn  -0.1064  -0.8011  0.0108  0.2244  0.7035  Cu  -0.2335  0.6542  0.3712  -0.2838  0.7267  B  -0.7672  -0.0570  0.3228  0.0830  0.7029  Sr  0.8066  -0.0714  0.1061  6.0935  0.6757  Ti  -0.1161  0.6882  -O.O636  0.1419  0.5112  0.2823  0.7897  0.2051  0.1411  0.7653  40.1281  0.2587  0.8063  -0.0295  0.7341  Ba  0.0933  0.0494  -O.836I  0.1193  0.7244  Ca  -0.0539  0.1246  -0.0019  -0.9023  O.8327  Fe  0.4039  -0.0256  0.6373  0.3217  0.6734  Na  0.8324  0.1397  -0.2215  0.1296  0.7783  -0.7388  0.0006  -0.1799  -0.0509  0.5809  V Mo  K  Eigenvalue i n % 31  29  23  17  215  Factor 2:  V, Ca, T i , Fe, Zn  Factor 3 s Ba, K Factor 1 i s an 'ore association',  Most pronounced scores  coincide with the subeconomic deposit (Discovery Zone) l y i n g south of the Lornex orebody. Low factor scores coincide with fresh Bethsaida rocks west of Lornex Fault. Factor 2 reflects lithology and p r o p y l i t i c alteration.  High  scores are associated with rocks of Skeena Phase east of Lornex deposit, with maximum values i n the propylitic zone marginal to the orebody.  In contrast, the more f e l s i c Bethsaida rocks west of the  Lornex Fault, and a r g i l l i z e d quartz porphyry i n the Discovery Zone are associated with low scores. Factor 3 reflects degree of K-feldspar destruction i n host rocks. High scores are confined to fresh Bethsaida and Skeena rocks to the west and east of the Lornex orebody respectively.  In contrast,  low scores are associated with the Discovery Zone and the periphery of the main orebody where K-feldspar has been destroyed, by p r o p y l i t i c and a r g i l l i c alteration. ( i i ) Subsurface Samples Element associations f o r the 4 factors are summarized as follows: Factor 1:  Na, Sr vs K, B  Factor 2:  V, T i , Cu ys Mn, Zn  Factor 3s  Mo, Fe vs Ba  Factor 4:  Ca, Zn  216  Factor 1 reflects hydrothermal alteration.  High factor scores  occur at the periphery of the orebody i n Hole 51 (Fig. A72).  Low  scores are associated with the central zone and ground adjacent to the Lornex Fault where intense potassic and p h y l l i c alteration are prevalent. Factor 2: Factor 1.  Distribution of t h i s factor i s almost the reverse of  I t reflects Cu mineralization (Cu sulphides i n association  with magnetite).  High scores are confined to a broad central zone of  intense metallization and alteration.  Low scores occur at the  ^periphery of the deposit (Fig. A 7 3 ) . Factor 3 reflects Mo mineralization.  Most pronounced scores occur  i n Holes 10 and 8 where Mo mineralization i s most intense (Fig. A74). Low scores are associated with Bethsaida rocks and potassic alteration immediately east of the Lornex Fault. Factor 4:  High scores of this factor occur along the Lornex  Fault and periphery of the orebody i n Hole 51•  low scores coincide  with the area immediately east of the fault (Fig. A75)»  This factor  mainly reflects metal enrichment along the Lornex Fault. (f) General Discussion and Summary Background concentrations of V, T i , CaO and FegO^ are higher i n rocks of the Skeena Phase i n the eastern part of the property than i n fresh Bethsaida rocks west of Lornex Fault*  This  i s consistent with the higher modal content of ferromagnesian iidnerals i n rocks of the Skeena Phase. However, Mn i s r e l a t i v e l y higher i n rocks of Bethsaida Phase reflecting the abnormally high Mn content  217  of biotites i n the Bethsaida Phase (Chapter 7» Table Lix). Hydrothermal effects are associated with extensive leaching of Zn, Mn, Fe, Na, Sr and Ba i n the central zone of intense a r g i l l i c alteration.  This i s attributed to complete breakdown of ferro-  magnesian minerals and plagioclase t o s e r i c i t e and kaolinite. In contrast, the peripheral propylitic zone with abundant chlorite, epidote and pyrite i s r e l a t i v e l y enhanced i n Zn, Fe and Mn. Anomalous concentrations of K and Ba are associated with potassic alteration immediately east of the Lornex Fault. The sharp truncation of geochemical anomalies by the Lornex Fault i s consistent with geologic evidence which suggests post-mineralization movement along the f a u l t . Compared to adjacent l i t h o l o g i e s , gouge along the Lornex Fault i s enriched i n Zn, Mn, Hg, Pb, Ag and CaO but show no enhancement<in Cu, Fe, Co and N i . Epigenetic metallization i s associated with pronounced anomalies of Cu, Mo, B, T i and V. Relatively high T i and V r e f l e c t magnetite within the ore zone. V a r i a b i l i t y i n Cu values i s examined i n Table XLVII.Coefficients of variation, i n l o c a l background samples are higher than i n mineralized samples. This i s attributed to the more uniform distribution of fractures i n ore zones than areas peripheral to mineralization, Geochemical contrast between background and mineralized environments i s summarized i n Table XLVIII, contrast.  Cu and Mo show best  In the eastern part of the property Cu and B halos extend  at least 1000m from the orebody, but are sharply truncated i n the west by the Lornex Fault, Dispersion of the other elements does  218  TABLE XLVII:  Comparison of v a r i a b i l i t y i n copper contents of background and mineralized samples, Lornex.  Drill-hole #  No, of  Log. mean  samples  Log. std. deviation  ^Coefficient of variation  Background samples Hole 49  69  1.025  0.707  0.69  Hole 51  67  2.746  0.539  0.20  Mineralized Samples Hole 12  72  3.482  O.313  0.08  Hole 8  78  3.549  0.234  0.06  Hole 10  94  3.556  0.175  0.05;  Hole 9  49  3.451  0.317  0.09  *Coefficient of variation = standard deviation/mean  219  TABLE XLVIII;  Comparison of metal contents and contrast i n background and mineralized areas, Lornex property (Values i n p.p.m. except where indicated.)  of samples  i.  Local background (Skeena)  Mineralized Zone  (6)  (51)  (60)  Contrast (regional)  Contrast (local)  Cu  26  149  2180  84  14  Zn  19  33  29  1.5  1.5  Mn  312  253  193  *1.6  Mo  2  5  13  6.5  2.6  B  5  11  18  3.6  1.6  Ti  1000  1022  1237  1.2  1.2  V  35  35  40  1.1  1.1  Sr  653  5^5  433  *1.5  *1.3 .  Ba  550  445  383  *1.4  *1.2  1.73  1.47  1.88  1.1  1.3  4.78  3.29  2.10  *2.3  *1.6  %o 2  ^Regional background (Skeena)  Na 0 2  *1.  Geometric means except f o r major elements.  2 Arithmetic means and values i n wt. %, ^Fresh samples of Skeena Phase collected by Northcote (1968).  4  Samples at the periphery of the deposit. Negative contrast.  220  not extend beyond the periphery of the ore zone (Fig. 52).  In  surface samples, positive scores of Factor 1 (B, MO, CU vs Na, Sr) are as extensive as the halos of Cu and B.  Because of sampling  limitations, positive factor scores i n subsurface samples are confined to the alteration envelope (Fig.  53).  HIGHMONT Results of trace and major element analyses i n surface and d r i l l - c o r e samples axe summarized i n Table XLIX and Figs. A76 to A86.  Surface samples comprise outcrop samples from background areas  and suboutcrop samples from the No. 2 Ore Zone (West P i t ) and the periphery of the main orebody (No. 1 Ore Zone or East P i t ) .  Sub-  surface samples were collected from a cross-section which includes background and mineralized zones.  Sample locations and plans are  presented i n the Appendix. Analytical techniques are the same as described f o r Lornex. (a) Geochemical Patterns Related to Lithology Rocks of the Skeena Phase within Highmont are characterized by higher Zn, Mn, T i , V, FegO^, KgO and CaO and lower Na and Sr relative to the more f e l s i c rocks of the Bethsaida Phase and Gnawed Mountain Porphyry (Table L ) . A Student t-test suggests that these differences are only significant f o r T i , V and FegO^ at the confidence l e v e l .  .05  The r e l a t i v e l y higher levels of the 'femic'  elements are attributed to the r e l a t i v e l y higher modal proportions of ferromagnesian minerals i n Skeena rocks. Compared with the Bethsaida Phase, the Gnawed Mountain Porphyry i s characterized by lower  -Limit of sampling  Limit of sampling.  650 ppm  Regional background • 550 ppm  2 0 0 ppm  '653 ppm  Sr 200ppm  •312 ppm  960 ppb  76ppm I9ppm  Zn  I2ppm  15 ppm  • 2 ppm  J •26ppm  I  1  1  Phyllic  Argil lie  B  Propylitic  Propy-Argillic  S  Bethsaida Phase  S  ORE  Skeena Phase  ZONE  X  SCALE  B FIGURE  1  B 52:  S  Schematic Lornex  diagram  subsurface.  showing  S extent  (* Regional  400m  and  data  relative  intensity  inadequate)  of  primary  halos,  FIGURE 53:  Schematic diagram showing distribution of factor scores, Lornex Subsurface.  TABLE XLIX:  1 2 "Means and ranges o f t r a c e and major elements a t Highmont. Surface Samples  No. o f samples  Subsurface Samples  (188)  (95)  A l l Samples (283)  K e t a l content (p.p.m.) Cu  108  111  (19 - 634)  (15 - '809)  18  Zn  (15 - 26)  176  (152 - 349)  12  Ti  (5-24)  761  (450 - 855)  1464  999  (1000 - 2143)  (659 - 1513)  38  (25-44)  2  12 (4 .- 37) 768 e+94 - 1194) 1482 (1010 -  (26 - 52) 3  (1 - 11)  642  (1 - 8) 627  500 (281 - 887).  (405 - 1015)  2174)  35  4  (1-7) Ba  (117 - 272)  33  (26 - 55) M o  178  620 -  (504 - 1148)  V  (11 - 30)  10  (4 - 35) Sr  18 .  230  (116 - 268) B  (19 - 676)  19  (11- 30) M n  109  (391 - 1007)  M e t a l content (wt. %) Fe 0 2  1.92  3  (1.25  - 2.59)  (2.05 2  - 3.33) 3.71  (3.21-4.21) KgO  (1.53 - 2.55)  2.69  CaO  Ka 0  2.04  1.34 (0.82 - 1.86)  3.12 (1.62  - 4.63) 3.82  (3.20-4.44) 107 (0.89 - 1.84)  ^"Geometric means except 2 + Mean - 1 standard d e v i a t i o n ;  1.93 (1.31 -  2.56)  2.83 (1.79  - 3.87)  3.75 (3.17-4.34) 1.35 (0.82  - I.83)  224  L:  Means and ranges o f metal c o n c e n t r a t i o n s i n l i t h o l o g i c u n i t s , Highmont s u r f a c e ( f r e s h and weakly m i n e r a l i z e d samples).  Values  i n p.p.m. except where i n d i c a t e d ) .  No. o f samples  Skeena Phase  Bethsaida Phase  Porphyry  (103)  (21)  (46)  *65  *120  *103  Cu  (18 - 586) Zn  20  (12 - 33) Kn  195 (131 - 290)  B  10  (4 - 22) 774  Sr  Ti  (1 - 13)  (3.17 - 4.01) 1.37 .  (23 - 50)  (1-8)  3.59  2  (4 - 98)  (1.02 - 1.72)  (863 - 2038) 32 (20 - 52) *1 (1  -3)  554  654  (332 - 926) 1.71 (1.07 - 2.36) 2,77 (2.18 - 3.34)  3.70 (3.09 - 4.30) 1.15 (0.37 - 1.92)  •Geometric means except whore i n d i c a t e d . '''Arithmetic means, and v a l u e s i n wt, %, 2  1326  34  *2  2.86  K 0  (790 - 1743)  *2  (2.35 - 3-38)  1  (4 - 20)  1174  2.14  CaO  21  9  1644  (1.67 - 2.60) 1  (91 - 222)  (526 - 1210  666  3  (122 - 284)  142  (556 - 1088)  (448 - 990)'  S°  186  (3 - 30)  (512 - 116?)  (32 - 55)  Ba  (11 - 27)  14  798  42  *Mo  17  (17 - 850)  778  (1203 - 2246) V  (13 - 322)  K e a n - 1 standard d e v i a t i o n .  (362 -941) 1.20 (0.68 - 2.11) 2.04 (1.40 - 2.96)  3.96 (3.41 - 4.58)  0.94 (0.42 - 2.10)  225  GaO, KgO, Fe 0^, Zn, Mn and higher T i , B, Ba and Na 0. Except 2  2  f o r B, Mn and Ti these differences are not significant at the .05 confidences l e v e l .  Metal concentrations i n fresh Skeena and Beth-  saida rocks within Highmont property do not d i f f e r appreciably from regional data. (b) Geochemical Patterns Related to Hydrothermal Alteration Hydrothermal alteration i s most pronounced i n d r i l l - c o r e samples. Table U L I f i shows metal concentrations i n relation to alteration types.  Enhanced Zn (>25  p.p.m.) and Mn (>250 p.p.m.)  concentrations occur i n a central zone which includes the Nos. 1 and 4 Ore Zones i n both sides and within the central porphyry dyke (Figs. A 7 6 and A 7 7 ) .  Low values occur at depth i n the dyke (Hole 69-108),  and Hole 69-126 which transects a small quartz porphyry north of the ore zone. A significant positive correlation between Mn and Zn (r = 0,64) demonstrates the s i m i l a r i t y i n t h e i r d i s t r i b u t i o n , Fe 0^ and Na 0 are r e l a t i v e l y depleted i n the central dyke 2  2  (Hole 69-108) and the quartz porphyry (Hole 69-126),  In contrast,  high values are associated with the ore zone where propy-argillic alteration (chlorite-serlcite-albite-epidote) i s associated with pyrite and other sulphides (Figs. A78 and A79). consistent trends related to alteration.  GaO and KgO show no  Sr values are depleted  within the ore zone. (c) Geochemical Patterns Related to Mineralization Copper:  Cumulative l o g probability plot of Cu values i n 283 samples  shows two populations, A and B, i n the proportion of 80 and 20$  TABLE L I i  * K e t a l c o n c e n t r a t i o n s a s s o c i a t e d w i t h types o f a l t e r a t i o n , Highmont p r o p e r t y .  '  "  ' " Skeena Phase  "  '. ~  Cu  Propylitic Zone  (6) .  No. o f samples  ,  ~~ *  2  299  6  (93 - 967)  -  309  (250 - 340) 5  (242 - 395) . 2 2 (7-32)  653  Sr  (625  Ti  •  V  615  - 680) .  (409 - 923)  1000  1280  (900 - 1200)  (871 - 1881)  35  35  (30 - 40)  Mo  (28  2  - 42) 7  (2 - 23)  Ba  742  IH!-  125  (193 - 2847)  550  442  (500 - 600)  (200 - 976)  (16  ' (28 - 545)  18  21  (16 - 30)  •'•312  B  ;  12  24  (22 - 35) Mn  ()  Argillic Zone  ~ Metal content (p.p.m.) _  19  2  Propy-Argillic Zone  (22)  (9 - 45). ,  Zn  ,  - 27)  (12 - 28)  232  297  (188 - 286)  (202 - 438)  18  17  (4 - 65)  (8 - 36)  558  508  (407 -763)  . (364 - 709)  1041  1062 685 - 1  (585 - 1850)  38  27  (31 - 47) 7  (15  - 48) 3  (2 - 26) 550  ( 1 - 5) 518  (317 - 955)  (263 - 1019)  M e t a l content (wt. % )  Fe„0.  2.14  2.98  2 3  2.94  1-89  W  (2.80 - 3.47) CaO  3.84  3.25  (3.73 - 3.91)  Na 0 2  4.78 (4.38-5.19)  KgO  (1.79 - 2.49)  1.73 (1.30 - 1.96)  (0.44 - 6.06) 3.61 (3.02-4.60) 1.49 (0.87 - 2.11)  (2.39 - 3.88) 3.23 (2.17 - 4 . 0 9 ) 3.95 (2.69 - 4.80)  1.46 (1.00 - 1.92)  (1.18 - 2.59) 2.84 (1.98 - 3.07) 3.45 (3.26-4.04) 1.32 (1.09 - 1.59)  •Means and ranges (range - mean - 1 standard d e v i a t i o n ) +  •••HF-HCIO^ d i g e s t i o n 2  A q u a r e g i a d i g e s t i o n (Brabec, 197°)  FIGURE 53:  Probability (cum.%) Log p r o b a b i l i t y p l o t of Copper at Highmont.  228  respectively (Fig. 5*0 • The value separating the two populations i s 18 p.p.m. Population B, with a mean value of 7 p.p.m., represents background samples comprising surface and d r i l l - c o r e samples. Population A, with a mean of 224 p.p.m., corresponds to anomalous samples. Cu distribution i n surface samples i s erratic because of the numerous Cu showings i n the region, especially south of the porphyry dyke.  In this area, enhanced Cu levels (>250 p.p.m.)  are dominant (Fig. A80).  In contrast background concentrations  (<18 p.p.m.) occur north and northeast of the major orebodies 1 and 2 ore zones).  (Nos.  As the mineralized zones are approached from  the north, Cu levels increase to a range of 100 to 400 p.p.m. In subsurface samples, l o c a l background Cu content  (<35  p.p.m.) i s associated with peripheral d r i l l holes (69-122 and 70270) and most of the central porphyry dyke. Anomalous values are encountered immediately north and south of the dyke, defining Nos. 1 and 4 Ore Zones respectively (Fig. A8l). Molybdenum} Mo concentration i s generally below the detection l i m i t (<2 p.p.m.) i n surface samples.  In the subsurface, low values  (<5 p.p.m.) occur i n marginal holes (Holes 70-270, 69-122 and 69126) and within parts of the porphyry dyke (Hole 69-108). Enhanced levels (>8 p.p.m.) are associated with mineralized zones, north and south of the porphyry dyke (Fig. A82).  Correlation between Mo  and Cu ( r = O.58) i n subsurface samples reflects overall s i m i l a r i t y in t h e i r distribution.  229  Boront  Anomalous B i n surface samples (10-2000 p.p.m.) occurs  dominantly within the NW-SE trending porphyry dyke and associated breccia pipes (Fig, A83). At the periphery of the main orebody, enhanced B levels (10-80 p.p.m.) are common. Elsewhere, B content i s less than 5 P.p.m. In subsurface samples, B concentrations are less than 20 p.p.m. i n marginal holes (Hole 70 - 270, 69-122 and 69-126).  High values  (>5°  p.p.m.) are encountered i n the porphyry  dyke (69-108) and adjoining mineralized zones (Fig. A84).  High B  levels i n surface and subsurface samples are attributed to the presence of tourmaline (schorl). relationship with Cu ( r =  0.19),  Alth6ugh B shows no significant there i s a weak but significant  positive correlation between B and Mo i n subsurface samples ( r = O.38).  (d) R-mode Factor Analysis R-mode analysis was applied to 13 variables i n 95 subsurface samples at Highmont. Results are presented i n Tables L I I to LIV and Figs. A85 to A89. Element associations of 3-» 4 - and 5- factor models are summarized i n Table L. These models explain 52, 63 and 72$ of data v a r i a b i l i t y respectively.  A 5-factor model  i s consistent with known geologic and mineralogic data. Element associations characteristic of each factor are as follows: Factor 1: Cu, Mo, B Factor 2: Zn, Mn, Ca  TABLE L I I i  C o r r e l a t i o n m a t r i x , Highmont Subsurface  B  Cu  Mn  Zn Zn  - .99839  Mn  .63934  I.OOO76  Cu  .32258  .25570  1.00089  B  .18425  .39096  .41295  Sr  .00252  -.28141  -.13930  . -.21331  .99967  Ti .  .15578  .35187  .13500  .15009  .12885  .99850  V  .24638  .19431  .07990 '  .09190  .31157  .58066  .99872  Mo  .11170  .26642  .56574  .38321  -.15268  .30713  .19683  . .99748.  Ba  -.08272  -.03955  -.06424  .I6583  .35218  .12646  CAO  .44874  .; .36177  ..08738  .19354  • .15449 '  .17598  .30918  .04597  Fe 0  -.08629  .08882  -.11244  .03956 •  -.01755  .13698  .05503  -.10649  Na 0  '.17580  -.13934  -.08547  -.20041  .00978  -.32062  -.18991  -.26631  • -.12524  .06171  .11443  -.01578  -.22561  .17159  .15564  2  Ba  -  CAO  Sr  2°3  -  Na 0 2  1.00174 .  Ba  CAO  ' Fe 0 2  Na 0 2  3  Mo  .99687 '  -.04567 .  Fe  V  Ti  .20101  .99917  -.10591  .10270  .99972  -.06622  -.02028  -.27265  .99974  .39181  .15626  -.25672  -.25141  1.00081  .. '.26564  •  .26620 .  231  TABLE LIII:  Metal associations of different factor models, Highmont Subsurface. FACTOR ANALYSIS  FACTOR  5  3  1  Cu  Mo  Cu  B  Cu  Mo  Mo  B  B  Mn  vs Sr  vs Sr  IJ  2  Ca  Zn  Zn  Zn  Ca  Mn  V  Mn  Ca  Ba  Ba  K  K  K  Ba  Ti  V  Mn  V  3  vs Na Na  Sr V  vs Ti  Ti Fe  5  Na  232 TABLE LIV: Varimax Factor Matrix, Highmont Subsurface.  FACTOR 1  FACTOR 2  FACTOR 3  FACTOR 4  FACTOR 5  -O.I838  -0.0980  0.2392  O.8332  Communality  Zn  0.2093  -0.8300  Mn  0.3048  -0.7913  0.0141  0.1797  -0.2097  0.7955  Cu  0.8367  -0.1241  -0.0410  -O.OO56  0.1372  0.7327  B  0.6265  - 0 . 2 5 8 0  -0.1140  0.1335  -0.2128  0.5352  Sr  -0.1852  0.1128  -0.1595  -0.8452  0.1135  0.7997  Ti  0.2672  -0.2565  0.2730  -0.4775  -O.445O  0.6377  V  0.1348  -0.3104  O.2838  -0.6892  -0.2150  0.73.67  Mo  0.8227  0.2395  -0.0555  -0.0871  0.7448  O.OO58  Ba  -O.O838  -0.0392  0.7106  -0.3572  0.0221  0.6415  Ca  -O.O786  -0.7296  0.1887  -O.I974  -0.1382  0.6145  Fe  -0.2093  -0.0962  -0.3241  -0.0024  -O.7635  0.7411  Na  -0.2487  -0.1302  -0.2313  0.0389  -0.7442  0.6876  -0.0090  0.8832  0.1819  -0.0188  O.8282  K  0.1208  Eigenvalue i n %  23  23  19  1 8  17  233  Factor 3i  K, Ba  Factor 4»  Sr, V, Ti  Factor 5»  Fe, Na  Factor 1 i s an ore association. Most pronounced scores are associated with mineralized zones on both sides of the central porphyry dyke (Fig. A85).  Minimum factor scores are confined to  marginal holes (Hole ?0-270 and 69-122). Factor 2: stood.  The significance of this factor i s not well under-  I t s distribution i s similar to that of Zn and Mn, i n that  high values are confined to a broad central zone encompassing the porphyry dyke and adjacent mineralized zones. Low factor scores are confined to peripheral holes (Fig. A86). Factor 3 reflects the distribution of potassic minerals.  High  scores are associated with the central porphyry*dyke containing r e l a t i v e l y abundant K-feldspar veins and a r g i l l i c alteration i n which s e r i c i t e i s a dominant mineral.  Low scores occur within the  ore zone and fresh Skeena rocks at the periphery (Fig. A87). Factor 4 broadly reflects lithology.  High scores are associated  with Skeena rocks north and south of the central dyke.  In contrast  low scores characterize the central porphyry dyke (Hole 69-108) and the small f e l s i t e dyke i n Hole 69-126 (Fig. A88). Factor 5 corresponds with intense p r o p y l i t i c alteration.  High  scores occur within the ore zone where p r o p y l i t i c minerals (chlorites e r i c i t e - a l b i t e ) are associated with pyrite and other sulphides.  234  Low factor scores are associated with areas outside the ore zone where rocks are either fresh or affected by a r g i l l i c and potassic alteration (Fig. A89). General Discussion and Summary Concentrations of Zn, T i , V and ^2°J are-higher i n fresh Skeena rocks relative to the more f e l s i c rocks of the Bethsaida and Gnawed Mountain Porphyry Phases. This i s attributed to greater abundance of ferromagnesian s i l i c a t e s i n Skeena rocks. Hydrothermal effects within the propylitic zone i s r e l a t i v e l y weak, and associated with subtle changes i n metal concentrations relative to fresh rocks. A r g i l l i c alteration i s associated generally with leaching of Mn, Zn, Fe, Ca, Na, Sr and Ba.  This i s  attributed to the breakdown of plagioclase and ferromagnesian minerals to kaolinite and s e r i c i t e .  Furthermore, the close s p a t i a l association  between a r g i l l i c alteration and the quartz porphyry partly accounts for the lower concentrations of 'femic' elements within the a r g i l l i c zone.  In the mineralized zone where propy-argillic alteration i s  dominant, concentrations of Ba, Zn, Sr, T i , V, Ca and K are higher than those of the a r g i l l i c zone but lower than those of the propylitic zone. This reflects the: intermediate nature of the propy-argillic zone. Nevertheless, Fe and Na are higher i n this zone relative to the propylitic and a r g i l l i c zones.  This i s consistent with the higher  albite and pyrite contents. Anomalous concentrations of Cu, Mo and B are associated with the mineralized zones.  This i s related to the occurrence of  235  sulphides i n association with tourmaline.  Cu i n l o c a l background  samples i s more e r r a t i c than i n mineralized zones where fracturing and intensity of epigenetic metallization i s more uniformly distributed (Table LV). Geochemical contrast between background and anomalous samples i s presented i n Table LVI.  Gu,Mo and B show the best contrast.  However, halos of Cu and B are generally the most extensive (Fig. 55), exceeding 200m i n the north and 50° m i n the south.  Distribution of  positive scores of a l l factors are confined to the mineralized zones and the alteration envelope on both sides of the main porphyry dyke (Fig. 56). SKEENA Results of analysis of samples from a d r i l l hole which transects one of the main quartz lodes at the Skeena Cu deposit are presented i n Figs. A90 and A91.  Pb, Cd, Co, N i , B, Sr, Mo, V,  Ti and Ba and NagO show no appreciable trends and are not discussed further.  Distribution of Cu, Zn, Mn, CaO, Fe„0,, K,0 In the hanging wall, background contents of Cu, Zn and Mn are generally less than 20 p.p.m. f o r Cu and Zn, and 3°0 p.p.m. f o r Mn. Within 20m of the quartz lode, Cu, Zn, and Mn concentrations rise sharply (Fig. A90).  However, the intensely altered wall rock  (sericite-quartz-kaolinite) closest to the vein shows r e l a t i v e l y lower values, defining an aureole of metal depletion.  236  TABLE LVs Comparison of v a r i a b i l i t y i n copper contents of background and mineralized samples, Highmont.  D.D.H. #  No. of  Log. mean  samples  Log. std.  * Coefficient  deviation  of variation  Local Background Samples 70 - 270  86  1.100  0.624  O.57  69 - 126  45  1.865  0.776  0.42  69 - 114  57  2.089  0.620  0.30  69 - 108  59  2.246  0.606  0.27  Anomalous Samples 69 - 120  50  2.735  O.303  0.11  68-22  12  2.695  0.286  0.10  68 - 68  26  3.245  O.56I  0.17  -^Coefficient of variation = standard deviation/mean  23?  TABLE  Comparison between *metal concentrations i n background  LVIJ  and mineralized zones, Highmont. Regional background (Skeena) of samples (6)  Local background (Skeena)  Mineralized Zone  (3D  (33)  Contrast (regional)  Contrast (local)  Cu  26  24  369  14  15  Zn  19  18  22  1.1  1.2  Mn  312  200  274  1.4  **1.4  Mo  2  2  6  3  .3  B  5  6  17  3.4  3  35  36  36  1.0  1.0  Ti  1000  983  1106  1.1  1.1  Ba  550  586  482  **1.1  **1.2  Sr  653  676  55?  **1.2  **1.2  3Fe 0  2.98  2.02  2.25  **1.3  1.1  Na_0  4.78  3.76  3.86  1.2  1.0  V  2  3  3  ^ r e s h Skeena rocks collected by Northcote (1968), 2 Samples from the periphery of the deposit. •^Arithmetic means and values i n wt. %*  *  Geometric means except where indicated. Negative contrast.  sw  NE  Limit  of sampling  Limit  of  sampling  Regional Background (Skeena)  653 ppm  •,3l2ppm  170 ppm  30 ppm I9ppm Oppm  80ppm  •5ppm 50 ppm  •2ppm  26ppm  Propylitic  s  Argillic  No.4  s  v +  Phase  s  +  Highmont  Propylitic  S Skeena Phase  ZONE  diagram Subsurface.  showing  extent  s SCALE  + +  Schematic  Nal  ZONE^j Porphyry  Skeena  FIGURE 5 5 :  P r o p y - Argillic  200m  + and relative  intensity  of  primary  halos,  239a  FIGURE 56:  Schematic diagram showing the d i s t r i b u t i o n of f a c t o r scores, Highmont Subsurface  sw -Limit  Factor  5  Factor  4  NE  of sampling  Limit of sampling.  -ve  Sr,Ti,V  i-ve  Factor  3  i-ve  Zn.Mn.Ca Factor  2  Factor  I  Zn,Mn,Co  +ve  Propylitic  Argillic  Propy- Argillic  Propylitic  Skeena Phase  ro 200m  CD  240  In the footwall, geochemical halos f o r trace elements do not decay to background levels but remain consistently higher than values i n the hanging wall.  This i s attributed to greater abundance  of fractures and veins i n the footwall.  The apparent depletion of  trace metals i n wall rock adjacent to the.lode i s attributed to leaching during hydrothermal and metallization processes. Major element concentrations (CaO, Fe 0^, and K^O) i n the 2  hanging wall decrease as the p r o f i l e enters the alteration envelope (Fig. A9l). Highest values are encountered within the ore vein reflecting abundance of pyrite, carbonate, and s e r i c i t e .  In the  footwall, values decrease away from the lode, and at a distance of 10m become lower than levels i n the hanging wall.  Towards the bottom  of the d r i l l hole, values again increase, defining another zone similar to that surrounding the main lode. DISCUSSION This section compares and contrasts the nature of metal dispersion i n the various deposits, and discusses the factors responsible f o r the observed differences, and applications of the geochemical patterns to mineral exploration. Results of primary metal dispersion around prophyry-type deposits at Highland Valley indicate that variations i n the abundance of 'femic group' of elements (Fe, Mg, T i , V, Zn, Mn, Co) are cont r o l l e d dominantly by primary l i t h o l o g i e s .  This relationship i s  attributed to the strong geochemical coherence of the trace elements with Fe and Mg,  Because of s i m i l a r i t y i n ionic properties, these  24l  elements tend to substitute f o r Fe and Mg i n crystal l a t t i c e s of ferromagnesian minerals (Goldschimdt,'1954).  Except at Bethlehem-  JA where Zn and Mn are impoverished, concentrations of these elements are similar to those obtained i n regional samples. Thus, the host rocks surrounding the deposits are not peculiar i n 'femic' metal concentrations relative to rocks of s i m i l a r composition within the batholith. Despite the dominant control of lithology on the distribution of the 'femic' elements, minor redistribution by hydrothermal processes i s apparent at these deposits i n which a major host rock i s dominant. Thus at Valley Copper, Zn, Mn, Fe and Mg are obviously depleted i n central zones of intense alteration relative to the periphery of the deposit. At Lornex, Zn, Mn and Fe are enhanced i n the peripheral p r o p y l i t i c zone relative to adjoining fresh Skeena rocks. At Bethlehem-JA t h i s effect has been masked by the apparent coincidence of p r o p y l i t i c alteration with the more mafic rocks of Guichon Phase. Hydrothermal mobilization of the femic elements i s attributed to the breakdown of ferromagnesian minerals into  s e r i c i t e , epidote or chlorite.  Where s e r i c i t e i s the dominant  alteration mineral such as at Valley Copper, the femic elements are depleted whereas i n p r o p y l i t i c zones with chlorite and/or epidote they are enriched or remain unchanged i n concentration, f o r example, Lornex and Bethlehem-JA. The l i t h o p h i l e elements (Rb, Sr, Ba), i n association with K, Na and Ca, are most susceptible to metasomatic changes during metallization and hydrothermal processes.  Results of factor analysis  242  have consistently associated Na and Sr which are most commonly impoverished wherever alteration i s intense.  Unlike K, Rb and Ba,  these elements are not tied to v i s i b l e alteration minerals, and thus constitute sensitive indicators of metasomatftc processes. Ba dispersion patterns are not consistent i n the deposits examined i n this study.  At Valley Copper, values decrease from the  outer margins to the core of intense alteration.  In contrast, at  Bethlehem-JA, higher values are encountered within the ore zone. At Lornex, values generally decrease from the periphery to the core of intense a r g i l l i c alteration, although enhanced values are encountered within the potassic zone. The inconsistent behaviour of Ba i s related to i t s geochemical a f f i n i t y with K-feldspar, which i s a common mineral i n alteration zones of porphyry-type deposits. Nevertheless, the lack of overall correlation between K and Ba, suggests that Ba distribution, outside the potassic zone, i s not controlled by K concentrations.  At Bethlehem-JA, Valley Copper and  a large portion of Lornex orebody, Ba/Sr ratios consistently increase from less than 1 i-n background areas to more than 1. i n mineralized zones.  Where Ba and Sr both decrease, the greater depletion of Sr  than Ba i s attributed to greater s o l u b i l i t y of Sr relative to Ba i n thermal solutions (Tooker, 1963). The only exception to the above distribution pattern i s where gypsum or carbonate veins are l o c a l l y abundant, as i n the bottom of Hole 10 at Lornex. Thus, the use of Ba/Sr ratios produce more consistent and r e l i a b l e patterns that are devoid of obvious mineralogical control than either Ba or Sr alone.  243  Rb consistently follows K at Bethlehem-JA and Valley Copper. Enhanced levels of both elements are associated with zones of intense potassic and p h y l l i c alteration where K-feldspar and s e r i c i t e are dominant.  This covariant relationship i s attributed  to s i m i l a r i t y i n ionic properties and geochemical behaviour during magmatic and hydrothermal processes (Nockolds and Allen, 1953 • Heier and Adams, 1964). The source of enhanced values of Rb i s uncertain.  However, two p o s s i b i l i t i e s are suggested,  ( l ) Wall rock  metasomatism might result i n b i l a t e r a l exchange of material between centres of hydrothermal a c t i v i t y and outlying host rocks. (2) Hydrothermal f l u i d s contribute Rb d i r e c t l y from deep-seated sources. Magmatic d i f f e r e n t i a t i o n commonly culminates i n the enrichment of Rb i n residual f l u i d s that might ultimately become hydrothermal solutions (Holland, 1972). Guilbert and Lowell (1974) among others have suggested that K-feldspar i n potassic zones of prophyry copper deposits could be related to deep-seated, late-magmatic c r y s t a l l i z a t i o n which accounts f o r i t s early paragenesis i n the sequence of secondary mineral formation. I f t h i s supposition i s correct, the association between K and Rb may suggest a magmatic-hydrothermal source f o r the latter. In general, depletion of major and trace elements especi a l l y Zn, Mn, Sr and Na i n zones of intense metasomatism i s consistent with the model of mass flow of acidic hydrothermal solutions through grain boundaries, pores and other discontinuities i n rocks. This culminates at the metasomatic leaching of base elements and  244  deposition at the 'outer front' as reaction with wall rock neutralizes the solutions (Korzhinskli, 1968), Consequently, negative anomalies are most commonly characteristic of primary dispersion of femic and lithophile elements. Distribution of Cu and Mo are e r r a t i c i n a l l the deposits. This i s attributed to sampling problems associated with t h e i r irregular mode of occurrence mainly as f r a c t u r e - f i l l i n g s and veinlets. Relative abundance of Cu i s influenced by bornite to chalcopyrite ratios.  Higher Cu levels are encountered at Valley Copper where  bornite i s dominant, whereas abundant chalcopyrite at Bethelehem-JA i s reflected i n r e l a t i v e l y lower Cu values.  Mo and Cu d i s t r i b u t i o n  also r e f l e c t s metal zoning patterns at Valley Copper and Bethlehem-:JA;Mo i n both cases i s peripheral to Cu. Distribution of sulphide-held Cu as determined by KCIO^HC1 digestion i s s i m i l a r to that of t o t a l Cu because most of the Cu occurs as sulphides.  In contrast, sulphide Fe isolates the effect  of lithology from mineralization, and delineates zones with most abundant pyrite and/or chalcopyrite, or pyrite halos at Valley Copper and Bethlehem-JA. S shows pronounced anomalies and more consistent patterns than Cu or Mo.  This i s attributed to the fact that S not only occurs  i n Cu or Mo sulphides but also i n Fe sulphides (pyrite) which smoothens i t s dispersion patterns.  Relative abundance of S i s also influenced  by bornite; : chalcopyrite content as reflected by results at Valley Copper and Bethlehem-JA.  Pronounced anomalies of S i n bedrock around  porphyry Cu deposits have'important implications for,the use of f?0  2  245 gas i n prospecting f o r these deposits.  Rouse and Stevens (1971)  have found SOg anomalies i n s o i l gas and a i r over the Highland Valley deposits.  Most pronounced S0 anomalies occurred at Lornex, 2  and a lesser one at Valley Copper, possibly reflecting the lower bornite:chalcopyrite ratios at Lornex. Geochemical behaviour of potential pathfinder elements (Hg, B, C l , F) i s not consistent.  Hg defines a broad anomaly at  Bethlehem-JA but no such pattern i s apparent at Valley Copper. Gott and McCarthy (1966), i n a study of the porphyry Cu deposit near Ely, Nevada, found that Hg was enriched i n rocks around the ore deposits and depleted i n the central ore-bearing intrusive rocks. This distribution pattern was attributed to the higher temperature prevailing i n the centre of the ore deposit which caused v o l a t i l e Hg to move outward, forming a halo around the deposit. Brown (1967) reported Hg anomalies i n s o i l s over porphyry Mo deposits i n the Canadian Cordillera.  McCarthy (1973) noted that Robbins (1972) and  the staff of U.S. Geological Survey, working independently, found no significant anomalies of Hg i n a i r around porphyry Cu deposits i n Arizona.  Similar results were obtained by \McNerney and Buseck (1973).  It i s apparent from these citations that the behaviour of Hg i n porphyry-type deposits i s not consistent, as t y p i f i e d by results obtained at Highland Valley.  Low Hg levels at Valley Copper and  enhanced concentrations at JA might be attributed to one or more of the following:  ( l ) higher temperature of ore formation at Valley  Copper caused the volatization and loss of Hg,  Relative high temp-  246  eratures at Valley Copper are suggested by f l u i d inclusion studies giving temperature over 350°C (Field et a l . , 1973) and up to 500°C by sulphur isotope geothermometry (j.Briskey, oral comm.). At Bethlehem-JA, no geothermometrlc  evidence i s presently available,  but the abundance of zeolites within the deposit i s remniscent of low-temperature 'hot-spring' - type a c t i v i t y (Meyer and Hemley, 1967);  (2) Loss or escape from fine-grained clay (Kaolinite) and  s e r i c i t e alteration minerals at Valley Copper compared to i t s retention i n coarser and more structured alteration minerals (Kfeldspar, c h l o r i t e , epidote) at Bethlehem-JA. Total Cl defines a moderate anomaly at Bethlehem-JA but i s e r r a t i c and low at Valley Copper. This behaviour i s contrary to expectations, as the size and grade of mineralization at Valley Copper and greater abundance of quartz-sericite veins should be accompanied by greater abundance of f l u i d inclusions.  Nevertheless,  the low C l concentrations at Valley Copper, might be due to v o l atization and loss as described above f o r Hg, or low s a l i n i t y of f l u i d inclusions.  F distribution at Valley Copper and JA i s e r r a t i c ,  which may be related to the e r r a t i c occurrence of epigenetic f l u o r i t e . There i s no significant correlation, however, between F and Cu. HjO - extractable Cl and F show even more e r r a t i c d i s t r i b u t i o n and no obvious relationship with mineralization,  Kesler et a l (1973) also  found no apparent correlation between contents of H 0 - leachable 2  Cl and F and the ore-bearing potential of intrusive rocks. B dispersion, though e r r a t i c , shows consistent relationship with mineralization.  This i s most obvious at Lornex and Highmont,  247  although high B concentrations i n the l a t t e r are associated with tourmaline. From the foregoing discussion of primary dispersion at Highland Valley, i t i s evident that the closely-related processes of hydrothermal alteration and metallization have introduced major changes i n metal abundances around porphyry-type deposits. Hydrothermal effects involving the formation of potassic minerals (sericite > K-feldspar) and associated metal redistributions and additions show consistent association with mineralization.  Because of the fine-  grained mineralogy of alteration zones, the intimate relationship between metallization and metasomatic effects has important implications f o r application of bedrock geochemistry to the search f o r porphyrytype deposits at Highland Valley and other areas.  Applications to Mineral Exploration Applications of regional geochemical data to exploration have been examined i n Chapter 5. surveys are discussed.  Here, detailed lithogeochemical  Table LVII summarizes geochemical contrast  and relative extent of halos at the various deposits. One of the principal objectives of detailed lithogeochemical surveys i n prospecting i s to delineate mineralized zones that are most suitable f o r further detailed exploration or mine development. On the basis of geochemical results obtained i n this study, the following observations are relevant to prospecting f o r porphyry-type deposits i n the Guichon Creek batholith and other  248  TABLE LVIIt  Comparison of relative contrast and extent of halos at Highland Valley deposits.  Bethlehem - JA  Valley Copper Contrast  Extent of Halos  Lornex  Highmont  Contrast  Extent of halos  ^Contrast Extent of Contrast Extent Halos of Halos  Cu  66  3  241  3  84  3  Mo  5  1  5  1  7  1  S  12  3  9  3  -  Hg  -  2  -  0  -  -  -  -  B  2  1  1  0  4  3  3  3  1  1  0  1  0  -  -  -  1  -  c  3  14  F  -  Rb  1  2  1  2  -  Sr  *2  2  *l  2  *2  2  *l  2  Ba  *1  2  *1  2  *1  2  *l  1  Zn  *1  0  *2  2  2  2  l  1  Mn  *2  0  *2  2  *2  2  1  1  Ti  -  0  -  -  1  1  *l  0  1  1  l  0  Cl  V  0  Extent of halos 0 = Nonexistent 1 = Narrowj confined to ore zone 2 = Extensive; within alteration aureole 3 = Very Extensive; beyond alteration aureole ^Negative contrast - Not applicable p Contrast i n relation to regional background  -  249  similar calc-alkaline intrusions, using bedrock, residual s o i l s and g l a c i a l overburden close to i t s source.  (1) S shows the most consistent and probably the broadest halos, extending at least 0.5 km from the ore zones at Valley Copper and Bethlehem-JA. Pronounced S anomalies i n bedrock suggests that SCv, in s o i l gas or a i r can be useful i n delineating mineralized zones at Highland Valley.  (2) Cu shows an extensive halo and high contrast, but i t s distribution i s e r r a t i c .  Its e r r a t i c behaviour i s attributed to  mode of occurrence principally as f r a c t u r e - f i l l i n g s and veinlets. Consequently, a large number of samples i s required to overcome the sampling problem and to establish reliable anomalies.  (3) Distribution of sulphide-held Fe using KC10^-HC1 attack can be u t i l i z e d i n delineating pyrite halos peripheral to porphyrytype deposits (e.g. JA and Valley Copper).  KClCy-HCl-extractable  Cu corresponds to Cu held i n sulphides, and hence constitutes a technique of improving geochemical contrast between background and mineralized environments.  (4)  In view of the close spatial and temporal relationships  between alteration involving potassic minerals ( s e r i c i t e , K-feldspar) and Cu mineralization i n the majority of porphyry-type deposits i n  250  North America (Guilbert and Lowell, 1973), the d i s t r i b u t i o n of Rb, Sr, Ba or K, Ca, Na can be useful i n outlining zones of most intense hydrothermal a c t i v i t y and metallization. Sr and Na have the greatest potential i n t h i s regard, because they are not t i e d to specific alteration minerals as are Rb, K and Ba.  Moreover,  the use of these l l t h o p h i l e elements has obvious advantages over mineralogical techniques because of the fine-grained texture of most alteration minerals.  (5)  The use of element r a t i o s , such as Ba/Sr and Rb/Sr, has  obvious advantages i n eliminating i r r e g u l a r i t i e s i n metal d i s t r i bution that might be attributed to mineralogical control or a n a l y t i c a l / sampling errors. 0.1  Ba/Sr ratios exceeding 1 and Rb/Sr ratios more than  broadly define mineralized zones i n the Highland Valley,  independent of rock and alteration types.  (6) Although no Hg anomaly occurs at Valley Copper, a pronounced and broad one i s associated with Bethlehem-JA. Thus Hg i n bedrock, s o i l s and s o i l gas and a i r might be useful i n delineating orebodies similar to JA.  (7)  B constitutes a potential pathfinder f o r deposits  associated  with breccia pipes and quartz porphyries as at Highmont and Lornex.  (8) Cl and F, either as t o t a l or water-extractable, consistent relationship with mineralization.  show no  Moreover, contrast  251  between background and mineralized areas i s very weak. Consequently, the use of halogens i n bedrock, s o i l or a i r probably has no potential f o r exploration i n the Highland Valley.  (9) In the absence or scarcity of outcrops, suboutcrop samples collected by d r i l l i n g below overburden can be u t i l i z e d f o r bedrock geochemical studies, especially i n heavily drift-covered areas.  (10) Factor analysis constitutes a potent tool i n analyzing relationships among elements i n multi-element geochemical studies. In this study i t has proved useful i n i s o l a t i n g element associations related to d i s t i n c t processes, such as hydrothermal alteration or mineralization.  Furthermore, results of factor analysis have been  consistent with subjective interpretations and known geologic and mineralogic evidence. CONCLUSIONS In a l l the porphyry copper deposits examined i n t h i s study similar geochemical patterns apply. Variations i n contents of •femic* elements (Zn, Mn, T i , V, Fe, Mg) are related principally to primary l i t h o l o g i e s , although effects of hydrothermal redistribution are apparent. The lithophile elements Sr, Ba, Na and Ca are sens i t i v e indicators of hydrothermal processes. These elements are consistently depleted i n zones of intense a r g i l l i c and p h y l l i c alteration, and metallization, whereas K and Rb, not appreciably depleted  252  i n these zones, are enriched i n potassic and p h y l l i c zones which are, i n some deposits, associated with mineralization. show the most extensive anomalies and highest contrast. are useful i n delineating mineralized zones.  Cu and S Hence, they  Hg and B constitute  useful pathfinders f o r some porphyry copper deposits such as JA, lornex and Highmont. On the "basis of pronounced S and Hg anomalies i n bedrock, S0£ and Hg i n s o i l gas and a i r can be useful i n rapid or reconnaissance exploration f o r porphyry type deposits i n the Guichon Greek batholith.  CHAPTER SEVEN MICRO-GEOCHEMICAL DISPERSION IN MINERALS  254  INTRODUCTION In recent years, numerous workers have investigated the use of trace element contents of mineral phases, especially b i o t i t e , i n geochemical exploration (see Levinson, 1974, pp. 336-341). However, the emphasis of the majority of these studies has been to use metal contents of minerals i n differentiating barren from potentially ore-bearing intrusions (Parry and Nackowski, 1963; Putman and Burnham, 1963; Al-Hashimi and Brownlow, 1970; Blaxland, 1971). Relatively few workers have assessed application of mineral geochemistry to either defining primary halos around orebodies, or i n enhancing geochemical contrast between background and mineralized environments. Lovering et a l . (1970), investigating Cu content of b i o t i t e in a large ore-bearing stock at S l e r r i t a Mountains, Arizona, found that Cu concentrations increased from a few p.p.m. i n the northern part to as much as"L%near Cu deposits at the southern end. Corresponding Cu content of bedrock showed only a subtle increase from 5 to 300 p.p.m. The authors concluded that trace element content of biotite i s a more sensitive and extensive indicator of mineralization.  Darling (1971) reported that the concentrations of  Cu and other trace elements i n biotite increased as the Pine Creek W-Mo-Cu orebody i s approached, although he did not present corresponding data f o r whole rocks. Bradshaw and Stoyel (1968) investigated trace element variations i n biotites and feldspars from granitic wall rocks of ore veins i n southwest England.  Their results  255  indicate that trace element contents of mineral phases showed similar, "but less well-defined anomalies than whole rock data. Trace element contents of magnetites have also been investigated as a guide to mineralization (see Levinson, 1974). High concentrations of Cu and Zn were reported by de Grys (1970) in magnetites from intrusions associated with porphyry Cu mineralization. magnetites  In contrast, Theobald and Thompson (1962) noted that from  rocks presumably associated with Cu mineralization  at Butte, Montana were relatively impoverished i n Zn.  Hamil and  Nackowski (1971) reported high abundances of Ti and Zn i n magnetites associated with major Pb-Zn mineralization, and low values with major Cu deposits.  Stanley (1964) found no correlation between Cu  content and modal proportion of magnetite i n whole rocks from the Granduc Cu deposit. Objectives of the present investigation are twofold; ( l ) to examine the nature of micro-dispersion of trace elements i n minerals from background and mineralized environments; and (2) to determine i f geochemical contrast between background and anomalous samples can be enhanced by chemical analysis of mineral fractions, u t i l i z i n g t o t a l and p a r t i a l extraction techniques. METHODS OF STUDY A suite of 26 granodiorites was selected from outcrop samples obtained from Highmont and Lornex properties (Fig. 57). Samples were separated into 3 groups on the basis of Cu content and proximity to mineralization. 10 samples containing less than  256  N BL  SK  «  LORNEX / BT BL  BLj  Bethlehem Phase  [si<3  Skeena Phase  BT  Bethsaida Phase  K3Mi  Gnawed Mountain Phase  L i t h o l o g i c boundary ~~» Fault © Orebodies • Background sample • Weakly anomalous sample • Strongly anomalous sample  BT  •\  GM  '73  BT  I 1  Ikm  FIGURE 57:  Location of rock and mineral samDles, Hiahland Vallev (Map a f t e r McMillan, 1973)  257  100 p.p.m. whole-rock Cu are considered as "background"; 7 samples with Cu values ranging from 100 to 600 p.p.m. are termed "weakly anomalous; and the remaining 9 samples with Cu values ranging from 601 to 5000 p.p.m.. are designated "strongly anomalous". Fourteen of the samples are equigranular rocks of the Skeena Phase, and the remainder are porphyritic rocks of the Bethsaida and Gnawed Mountain Phases. B i o t i t e , quartz-feldspar and magnetite fractions were separated by methods described i n Chapter 4. Preliminary petrographic examination indicated that the majority of samples contained l i t t l e or no hornblende (Table LVIIl), nevertheless hornblende was removed as an impurity. On the basis of chemical analysis, a l l mineral fractions are considered more than 90$ pure.  However, the  K content of biotites suggest a varying degree of c h l o r i t i z a t i o n , especially i n "anomalous" samples. No obvious relationship exists between K content of biotites and concentrations of trace elements (Table  LIX). This i s consistent with the observations of Putman and  Burnham (1963) and Graybeal (1973) that c h l o r i t i z a t i o n of b i o t i t e does not appreciably affect trace element content. Original samples were examined microscopically, and modal data obtained f o r 21 (Table LVIIl).  However, 4 samples were too  altered to obtain reliable modal analysis, and were replaced by other samples with similar Cu levels, f o r which modal and chemical data were available.  Plagioclase feldspars i n anomalous samples are  weakly to moderately s e r i c i t i z e d , although crystal form and twinning can s t i l l be observed.  Biotites are generally fresh, although a few  258  TABLE L V I I I i  Trace Element and Modal Content o f Whole Rock Samples  Modal Composition ( v o l , ya)** Trace Elements (ppm) Horn- K - f e l d - P l a g i o Cu Zn Kn B i o t i t e b l e n d e spar clase Quartz  SAMPLE HUMBEB  Accessories  GM 2  56  30  254  GM 10  11  31  250  SK 30  14  20  279  6.24  0.43  15.92  58.28  18.28  0.81  SK 34  27  43'  493  2.90  4.56  5.61  63.77  21.52  1.64  sx 36  34  30  345  3.40  1.1  14.8  55.43  25.00  0.03  BT 173  33  18  241  3.90  1.0  10.41  55.93  27.90  0.90  BT 176  51  31  353  7.55  0.06  6.70  57.13  25.82  2.14  BT 746  6  35  404  6.70  0.0  15.47  54.27  23.24  0.28  18  36  445  3.36  0.44  6.83  65.60  22.72  1.03  14  28  382  1.84  0.0  5.84  27.05  O.83  SK 19  542  42  366  2.05  4.28  3.21  68.13  21.19  1.14  SK 22  441  38  292  4.40  2.55  4.4  58.94  25.68  1.26  GM 114  185  18  132  3.02  0.0  3.02  66.12  24.45  0.37  GM 118  327  31  304  5.90  0.0  5.90  62.00  19.12  0.93  SK 178  147  37  383  0.75  1.89  0.75  66.38  25.28  0.47  BT 757  155  20  345  6.00  0.0  6.00  69.00  15.67  5.21  SK 776  539  24  214  3.23  0.0  3.23  62.95  22.-05  0.35  SK 7  2821  38  342  6.70  0.10  O.83  22.50  2.08  *SK 28  609  27  • 352  2784  25  193.  . 6.44  0.01  7.20  65.81  20.27  0.81  BT 748 BT 751  3K 29  •  64.02  67.78  *SK 31  4689  35  -jll '  *SK 35  1400  37  3^9  SK 50  182 8  22  284  3.19  0.0  1.39  62.52  31.66  1.39  SK 61  823  24  347  3.66  5.11  7.78  57.34  20.88  0.18  GM 115  609  34  234  12.10  0.0  6.30  53-86  28.75  0.74  GM 119  1748  23  196  5.93  1.25  5-93  52.41  33.86  0.98  SK = Skeena Phase;  BT = Bethsaida Phase;  Phase (-) Data not a v a i l a b l e ^Total digestion  GM Gnawed Mountain  * A l t e r e d sample.  **!-:ore than 1000 p o i n t counts p e r sample  259  are partly chloritized or s e r i c i t i z e d .  Sulphide inclusions occur  within and around the margins of many,of the b i o t i t e s , including those with background Cu content. Examination of polished-thin sections show that pyrite, bornite and chalcopyrite are the : dominant sulphides (Plate 13).  In "anomalous" samples, K-feldspar  i s altered to varying extent, and d i f f i c u l t to identify. Vein quartz i n some of the mineralized samples contains i n t e r s t i t i a l opaque inclusions which may be sulphides or oxides.  Modal ratio of  quartz to feldspar i n most samples i s approximately 1:3* In the following data presentation and discussion, "anomalous" and "background" samples refer to anomalous and background bedrock samples and t h e i r mineral fractions. RESULTS Results of chemical analysis of whole rock, b i o t i t e , quartzfeldspar and magnetite fractions f o r t o t a l Cu, Zn, Mn, Go and Ni and sulphide-held Cu, Zn and Mn are presented i n Tables LVIII to LX.  Appropriate correlation diagrams and coefficients are shown i n  Figs. 58 to 71 and Table LXI. Cu concentrations i n bedrock range from 6 to 4689 p.p.m. Geometric means f o r background and a l l anomalous samples are 21 and 745 p.p.m. respectively (Table L V I I l ) . (a) Biotite Trace element contents of biotites are tabulated i n Table LXIX.  Cu values range from 44 to 5617 p.p.m., and average 98 p.p.m.  for background and 1624 p.p:«>m. f o r anomalous samples.  Background  mean value f o r Cu i s similar to the mean value of 113 p.p.m. obtained  TABLE LIXi  Trace and major element contents of minerals.  - - -  4*  Biotite r'Jl  Zn  Cu  Fe 0  Ni  Co  2  K/jU  3  '—m-  Background Samples  52  MO SZ30 sz 34  49  3/. 3 6  149  =T 173 2T 17b  .  75  182  1515  35  279  3617  69  <*5  455  4960  72  31  39 27  193*  42  110  187  1*31*6  1*2  164  277  3695  70  51  3** 31  172  105  902  8771*  67  17 748  39  931  11225  59  565  6866  57  ST 7 5 1  226  33  98  31*9  4195  ' 56  40  H 746  ' :-'e&n  12.26  15.57  36  64  2322  275  123  ^2  Magnetite Cu  1.66  62  K  2°  153  94  36  66  22  0.74  122  20  16  32  0. 63  5.50  i.S;  30  1*9  18  16  1.66  4.47  3-27  12.72  2.31  35  13.70  13.91  2.10  1*3  65  48  16  21  1.48  i i * . 01  7.07  1.1*2  66  1*1*  44  62  29  1.70  1*7  1*3  22  135  26  1. f3  3.45  14.10  13.15  3.62  71  1*8  60  33  13  1.73  4.17  3.07  58  118  39  12  8  1.56  4.59  2.37  06  108  46  24  15  1.73  4.52  2.;5  87  88  »5  IS .  8  1.54  4.70  2.43  67  68  40  29  17  12.36  ...25 _  •  3.15 '  2.75 2.45  1*.20  832  64  y*  406  34  1.66  1*7  7.59  3.05  220  64  38  513  21  1.43  4.42  81*6  61  34  142  20  2.0?  4.67  i.fo  110  1*3  37  4S6  26  1.32  3.52  2.74  110  56  38  29  16  1.7S  4.50  2.66  93  55  49  127  11  1.45  4.75  2.73  390  38  59  318  12  I.65  4.29  2.57  251  9*  40  210  19  2420  26  3-25  1.85  sx 111*  673  21*8  sic 118  711  216  2161*  55  31*  1*83  259  2H81*  1*7  38  SK 757  2644  299  31*17  SK 776  1760  312  3171  883  292  3250  65  25  1*1*07  60 76 58  15-00  IO.05  1.81  5" 16.78  32  13.63  2.1*3  37  ' 5M*  55  24  l.'S  531  1*21  5821  5<*  21  sx 28  2*5  326  2898  1*2  34  2876  326  5256  1*6  12  629  68  36  2365  22  1.70  SX 29  <»9  31  51*51  73  36  3465  28  1.29  305  51  41  2195  29  i.r-4  175  1*8  29  384  18  1.56  sx 31  5617  29^  3296  SK 35  5310  iei  2038  1*5  1*1*  SK 5"  2736  198  1953  53  29  SK 61  1858  209  2798  53  21*  4.00  2.?i 3.27  (n - 9)  Strongly Anomalous Samples 12-5^  15.20  4.36  567  16.01  8.55  2.55  122  i*3  17  21*5  73  26  39  37  67  36  IO56  20  22  1.43  793  23  1.47  CK 115  2510  315  3022  288  31*10  1*7  23  421*6  64  37  1637  21  CK 119  251*9  275  320a  1*9  21*  576  59  33  1440  23  Ke&n  52  29  1*01  57  36  1.96  662  321*6  3227  4.20 3.79  15.1*8  1  390  288  2.53  15.32  1.71*  (yfcan (All^ Ar.ocaloun y  4.59  15-5 *  SX 22  sx 7  CaC  1*0  365  Hean  Zn  TAI  (n-7)  E13  SK 178 .  Cu  12.25  W.60 .  3X 19  1*388  Quartz-Feldspar Co  no  Veakly Anomalous Samples 31*03  Zn  619  1.42  4.J2  l.«6  4.49  2.04  4.04  2.25  3.12  2.17  4.34  3.13  4.12  3.15  4.67  2.17  4.44  2.24  ON  o  261  by Brabec (1970) f o r fresh biotites i n the Guichon Creek batholith, and to the average values of 75 and 90 p.p.m. cited by Putman and Burnham (1963) and Parry and Nackowski (1963) f o r unmineralized biotites from Arizona and Basin and Range province respectively. Cu contents of biotites from anomalous samples are considerably higher than those from background samples (Table LXIX).  Lovering  et a l . (1970) reported Cu values as high as 1% i n biotites from mineralized rocks i n Arizona. Similar high Cu values have been documented by Al-Hashimi and Brownlow (1970) and Graybeal (1973)• Levels of Co, Mn, Ni and Zn are consistently lower i n anomalous than background samples. However, the Student's t-test indicates that difference i s only significant f o r Ni at the .05 confidence l e v e l . (Table LX). (b) Magnetite Average Cu concentrations i n magnetites from background and anomalous samples are 67 and 401 p.p.m. respectively. Cu values exceeding 4000 p.p.m. occur i n two samples (Table LIX). Brabec (1970) obtained a mean Cu value of 398 p.p.m. f o r magnetites from the whole batholith.  This mean value i s conspicuously high,  perhaps indicating that magnetites from the r e l a t i v e l y older and more mafic rock phases contain high Cu values comparable to those found i n gabbros and ultramafics (Wager and Mitchell, 1951)• Differences i n analytical techniques might also account f o r the discrepancy.  Lyakhovich (1959) reported mean Cu values of 5 to 80  p.p.m. i n magnetites from unmineralized intrusives i n the U.S.S.R.  262  TABLE LXs Student's T test of background and anomalous samples.  T - Value  Background vs Anomalous  D.F  WrCu vs. WrCu  9.26*  24  WrZn vs. WrZn  1.62  20  WrMn vs. WrMn  1.85  19  BtCu vs. BtCu  9.25*  24  BtZn vs. BtZn  1.01  11  BtMn vs.Bt Mn  1.15  12  BtGo vs. Bt Go  0.94  24  BtNi vs. BtNi  2.07*  24  FQCu vs. FQCu  6.64*  24  FQZn vs. FQZn  1.32  24  MgCu vs. MgCu  5.34*  20  MgZn vs.MgZn  1.13  11  MgCo vs.MgCo  1.08  24  Wr = Whole rock; feldspar;  Bt = B i o t i t e ;  Mg = Magnetite; FQ = Quartz-  D.F. = Degree of freedom  * Significant at the .05 confidence l e v e l . 10 samples  16 samples  263  Al-Hashimi (1969) noted that Cu levels i n magnetites from the Boulder batholith range from less than 1 to 230 p.p.m. and average 40 p.p.m. Magnetites, are regarded as e f f i c i e n t concentrators of Zn (Theobald et a l . , 1962; de Grys, 1970). However, Zn content of magnetites examined i n this study ranges from 30 to 122 p.p.m. Levels of Zn and Co are consistently lower i n anomalous than background samples, although a Student's t-test suggests the difference i s not significant at the .05 confidence l e v e l . (c) Quartz-Feldspar Cu concentrations i n quartz-feldspar fractions range from 12 to 3465 p.p.m. and average 29 and 619 p.p.m. f o r background and anomalous samples respectively.  Mean Cu content of background  samples i s similar to mean values of 25 and 50 p.p.m. reported by Brabec (1970) and Bradshaw and Stoyel (1968) respectively.  Average  abundances of Zn i n background and mineralized samples are not signi f i c a n t l y different (Table LX). DISCUSSION Putman and Burnham (1963) and Putman (1972) have shown that variations i n bulk chemical composition (major and trace elements) between samples from a plutonic body have three main sources: ( l ) variations i n modal composition of the rock, with or without changes in mineralogy;  (2) variations i n chemical composition of constituent  minerals; and (3) variations related to endogenous processes, f o r example, hydrothermal alteration, mineralization, weathering or  264  TABLE LXIi  KC10,-HC1 extractable metal i n mineral phases. (Values i n p.p.m.) i-'agnetite  Biotite Cu  -  Zn  Mn  Cu  Quartz-Feldspar Zn  Zn  Cu  Background Samples (n = 10)  116  36  419  53  6  57  4  GM 10  32  27  305  -  -  11  6  SK 30  26  28  313  15  3  6  3  SK 34  22  42  311  46  3  8  6  SK 36  147  23  185  . 31  4  23  6  BT 173  112  21 '  839  30  4  106  8  BT 176  143  45  743  46  4  22  8  3T 746  79  191  2471'  29  4  BT 748  69  161  2532  41  4  20  8  BT 751  214  62  546  42  4  12  '5  GM 2  7.  5  VJeakly Anomalous Samples (n = 7) SK 19  820  50  566  519  15  382  8  SK 22  468  65  767  139  3  386  3  SK 114  683  62  1257  641  9  107  6  SK 118  638  31  249  62  5  456  7  SK 178  384  35  268  92  5  15  6  SK 757  2297  66  856  113  13  78  5  36  233  167  6  287  3  SK 776  1557  Strongly Anomalous Samples (n = 9) SK 7  459  43  512  921  5  1714  3  SK 28  2671  70  674  388  5  696  7  SK 29  2995  67  1174  676  10  1868 •  4  SK 31  5093  58  1573  1061  6  3253  6  SK 35  5022  255  251  3  1139  8  SK 50  2391  40  320  142  4  355  4  SK 61  2199  18  390  61  7  610  4  GM i l 5  2583  53 •  839  179  5  737  6  GM 119  2938  29  681  674  4  24  1392  7  265 metamorphism. Composition of mineral phases i s discussed i n relation to these factors. (a) Form of Trace Elements i n Mineral Phases The form of trace elements i n mineral phases was examined by sulphide-selective KCIO^-HCI digestion. Results are presented i n Table LXI and Figs. 58 to 60.  In background biotite samples with  less than 100 p.p.m. Cu, the proportion of Cu extracted ranges from 40 to 80$.  In contrast, more than 80$ of t o t a l Cu i s extracted from  background samples containing more than 100 p.p.m. Cu, and a l l anomalous samples with Cu values ranging from 384 to 5093 p.p.m. (Fig. 58).  In magnetites,  considerable overlap i s evident i n the  proportion of Cu extracted from background (34 - 75%) and anomalous (20 - 100%) samples (Fig. 59).  On the other hand, the proportions of  Zn extracted from biotites and magnetites, and Mn from biotites (Table LXl) are generally less than J0% i n both background and anomalous samples (Figs. 58 and 59 and Table L X l ) . In quartz-feldspar phases, the proportion of Cu extracted i n background samples range from 33 5° 84>2. In anomalous samples, proportion of Cu extracted increases from 60% at 100 p.p.m. t o t a l Cu to more than 95% at 500 p.p.m. (Fig. 60).  This i s followed by a  decline i n % extraction at more than 1000 p.p.m. t o t a l Cu. The extraction of Zn i n anomalous quartz-feldspar samples i s generally less than 35%» whereas i n background samples a considerable scatter i s apparent, with extraction ranging from 18 to 62% of t o t a l Zn. However, the 4 samples with more than k0% extraction are very low  266  Cu ©  Zn n  Anomalous Background  D  o °  • o  ® •  ©  o o  • •  10  FIGURE 58:  •  • • •  100  m  ' •  1000  10000  Total Cu (ppm) Proportions of t o t a l Copper and Zinc extracted from b i o t i t e s by KCIC^-HCI d i g e s t i o n .  26?  Cu  •  lOOh  Zn  •  8 ANOMALOUS  o  • BACKGROUND  •  «e  80  o°o  o  «  #  +j 60 o <o s+-> X  o  oo o  40  20  •  •q-,  10 FIGURE 59:  «a"  n  100  1000  T o t a l Cu (ppm) P r o p o r t i o n s o f t o t a l C o p p e r and Z i n c e x t r a c t e d m a g n e t i t e s by KC10 -HCT d i g e s t i o n . 3  10000 from  268  Zn •  Anomalous  O  Background  lOOr-  o o • o •  • o  •  o  ®  o  •  •  o  •  •  l_J  • • •  mm  •  •  •  II  B  H  •  a •  FIGURE 60:  — i ~  1000 10000 100 Total Cu (ppm) Proportions of t o t a l Copper and Zinc extracted from quartz-feldspar phases by KC10 -HC1 d i g e s t i o n . 10  3  269  in t o t a l Zn (8-15  p.p.m.), consequently the high % extraction i s  attributed to poor analytical precision at low concentrations. Results of sulphide-selective leach suggest that Cu occurs dominantly as sulphides i n mineral phases from anomalous samples. Some background samples also contain appreciable sulphide-held Cu. In contrast Zn i n a l l mineral phases and Mn i n biotites occur mainly in non-sulphide form, presumably i n substitution f o r Fe and Mg i n crystal l a t t i c e s . (b) Chemical Variations Related to Modal Composition Although there are no significant correlations between abundance of b i o t i t e and either whole-rock or biotite Cu (Fig. 61 and 62),  the amount of Cu contributed by b i o t i t e to whole-rock  samples increases with increasing modal b i o t i t e (Fig. 63).  This  positive relationship i s strongest f o r biotites from mineralized samples, and reflects the occurrence of epigenetic Cu, mostly as sulphide inclusions. A plot of whole-rock Cu versus modal proportion of accessory minerals (mainly opaque) exhibits no significant correl a t i o n f o r a l l samples, although a rather weak (r = 0.53)  positive  correlation exists between whole-rock Cu i n background samples and modal accessory minerals (Fig. 64). F i g . 65 shows that the amount of K-feldspar generally decreases with increasing Cu content of whole rocks.  This reflects increasing intensity of hydrothermal  alteration of K-feldspar to sericite i n mineralized samples. Whole-rock Zn shows no obvious correlation with b i o t i t e  2?0  A l l Samples Anomalous samples Background samples  r = 0.21 r = 0.30 r = -0.07  n = 21 n = 13 n = 8  + Strongly Anomalous Samples n  Weakly Anomalous Samples  ^Background Samples  IOOOCH  loocH Whole-Rock Cu IOOH  •© ©  2  FIGURE 61:  4  6  8  io  Modal B i o t i t e % Relationship between whole-rock copper and modal proportions of b i o t i t e .  12  271  A  Strongly Anomalous  •  Weakly Anomalous  «  Background  10000  g; 10001  r = 0.22  •  a  4->  n = 21  o  "~  100  o  10  4  FIGURE 62:  10 12 6 8 Modal B i o t i t e % Relationship between modal and Copper contents of b i o t i t e .  272  A l l samples Anomalous samples Background samples  r r r  0.51 0.75 0.60 A  n = 21 n = 13 n = 8 Strongly anomalous  a Weakly anomalous Background  CL CL  u o cn  cu o  A •  A  •nool cu +-> •(->  •  o  •r— CQ  •  o sq-  Q  •  I+->' 10 rt3 S+-> c: cu u c: o o  o o  CU  o  Modaf B i o t i t e f FIGURE 63:  12  Plot of modal b i o t i t e v e r s i s Copper from b i o t i t e in whole rock  273  4-  ,000  A l l Samples Anomalous Samples Background Samples  °-f  1OO0'  •  Strongly Anomalous  •  Weakly Anomalous  9  Background  r = 0.24 r = 0.17 r = 0.53  n = 21 n = 13 n = 8  +  + • •  +  •  • •  Q. CL  3 O  '  100-1  o o I  a>  o  sz  10-  0 FIGURE 64:  1  2  3  4  5  Modal Accessory Minerals % Relationship between whole-rock Copper and percent accessory minerals in rocks.  274  10000  A  Strongly Anomalous  •  Weakly Anomalous  •  Background  r = -0.55 n = 21  1000 • D • 100  10  0  FIGURE 65:  4  8  12  16  20  Modal K-feldspar % Covariance of Copper and modal K-feldspar in whole rocks.  275  i n a l l samples (Table LXIl), although a relatively weak positive correlation i s apparent between whole-rock Zn and combined modal biotite and hornblende i n anomalous samples. Nevertheless, the amount of Zn contributed to whole-rock samples by b i o t i t e increases with increasing modal b i o t i t e (Fig, 66). (c) Variations Related to Ghemcial Composition of Mineral Phases 13 biotites were analyzed f o r Mg and Fe, and 26 quartzfeldspar fractions f o r Ca, Na and K (Table LIX).  However, results  f o r quartz-feldspar do not show any consistent relationships with trace elements, and consequently are not discussed further. Biotites Putman and Burnham (1963) have shown that major element composition of biotites can influence trace element content.  Gray-  beal (1973) found no obvious correlation between Cu and major elements in b i o t i t e , although he obtained a weak positive correlation between Zn and Fe i n b i o t i t e . Biotites from mineralized samples are characterized by r e l a t i v e l y high Fe and low Mg levels (Figs. 67 and 68).  This  reflects either the contribution of Fe from sulphide inclusions or suggest that hydrothermal processes during ore formation involved depletion of Mg and addition of Fe to b i o t i t e s , probably derived from magnetite. Plots of Cu content against Fe and Mg show positive and weak negative relationships between Cu and Fe and Cu and Mg (Figs. 67 and 68) respectively. Zn and Co values generally increase with increasing Mg contents of biotites (r = 0.50 and 0,60 respectively).  276  TABLE LXIIi  Correlation fatrlx for medial analysis and trace olercent content of rocks and minerals - significant Correlations at i05 confidence level-.  Variable  W?CU  WPZN  AU samples  BTCU  WRCU  1.0000  VfRZi;  -0.1158  1.0000  BTCU  0.8521  -0.2954  1.0000  BTZN  n  =?|  BTZN  K-F3P  -0.3948  0.5217  -O.35I8  1.0000  ET  0.2121  0.0760  0.2210  0.0520  1.0000  BT + HBD  0.1999  0.3248  0.1230  -0.0332  0.7527'  ACCESS  0.2389  0.0127  0.1478  -0.U35  0.0019  O.3690  K-FS?  -0.5468  -0.3982  -0.0614  0.0829  -0.0006  3T  3T + HBD  -O.I972 • Anomalous  Variable  WRCU  WRCU  1.0000  WRZN  Samples  BTCU  1.0000 1.0000 -0.3O48  1.0000  13 ETZi!  WRZN  0.0814  1.0000  BTCU  O.38O8  -O.5584  1.0000  BTZN  0.2189  0.4658  -0.2235  1.0000  BT  0.3027  0.2218  O.3676  O.3766  1.0000 0.7566 .  K-FSP  3T + HBD  0.1491  0.4671  O.I762  0.2549  ACCESS  0.1748  -0.0253  0.0730  -0.2611  -0.0705  0.3453  -0.4214  1.0000  K-FSP  -0.1895  0.1186  -O.2629  -0.0275  -0.0349  -0.1072  BTZN  BT  BT + HBD  1.0000  1.0000  Background Samples  Variable  WRCU  VSZN  BTCU  ACCESS  WRCU  1.0000  WRZN  -0.1036  1.0000  BTCU  0.1696  -0.0169  1.0000  BTZN  -0.6992  0.5989  -0.0603  BT  -0.0724  -0.1325  -0.1462  -0.0697  1.0000  0.12SO  0.1723  -O.555O  -O.I387  0.7280  1.0000  0.5273 -0.3942  0.2075  -0.1113  -0.0002  0.2123  0.4212  1.0000  -0.392S  -0.2293  -0.2613  0.4392  0.2238  -0.71S6  BT + h33 ACCESS K-FSP  K-FSP  1.0000  1.0000  277  A l l samples Anomalous samples Background samples  r = 0.73 r = 0.88 r = 0.56  E  n = 21 n = 13 n = 8  A  Strongly Anomalous  •  Weakly Anomalous  •  Background  Q. D. o o s-  40r  OJ  4->  •  O Q  o s4-  10  s-  4-> CU  o c o u  cu •a o  o o  •  4  Modal B i o t i t e % FIGURE 66:  6  10  12  Plot of modal b i o t i t e versus Zinc from b i o t i t e in whole rocks.  278  10000 -0.59  • •  1000 D Q  Q.  CD +-> O  100  lilted  -Q  10  16 12 14 MgO i n B i o t i t e (wt %) Copper versus. Magnesium i n b i o t i t e s 10  FIGURE 68:  r = 0.50 n = 13  •  Anomalous  *  Background  • •  13  14  15  16  Fe as F e 0 i n B i o t i t e (wt %) 2  FIGURE 67:  3  Copper versus Iron in b i o t i t e s  17  279  This relationship i s consistent with the ionic substitution of these elements f o r Mg i n b i o t i t e l a t t i c e s .  Lack of correlation  between Zn and Go, and Fe probably reflects the presence of epigenetic Fe as sulphide inclusions. (d) Chemical Variations Related to Mineralization Variations i n trace element chemistry of minerals, i f d i r e c t l y related to mineralization may be useful i n geochemical exploration.  In the anomalous samples examined i n t h i s study, a l l  mineral phases are enriched i n Cu which i s p r i n c i p a l l y present as sulphide inclusions (Figs. 69, 70 and 71;  Table LIX).  This i s  suggestive of an endogenous process producing a "blanket" enhancement effect on a l l rock constituents. ( i ) Biotites Biotites commonly are enriched i n Cu which occurs dominantly as minute sulphide inclusions. Numerous workers (Lovering et a l . , 1970;  Putman and Bumham, 1963 j  Al-Hashimi and Brownlow,  1970)  have demonstrated that igneous biotites tend to have low Cu contents unless hydrothermal alteration and/or mineralization are associated with t h e i r host rock. This contention i s supported by results of sulphide-selective leach (Fig. 58) and the strong positive correlation between whole-rock Cu and b i o t i t e Cu (Fig. 69).  Petrographic  evidence, which i s consistent with chemical results, indicates that Cu occurs partly as small inclusions of bornite and chalcopyrite i n b i o t i t e , and also along margins of ragged grains of femic minerals (Plates 14 and  15).  280  4-  Highly Anomalous Samples  •  Weakly Anomalous Samples  m  Bakcground Samples  r = 0.88 n = 26 10000H  +  +  1000-  •  •  :•  100-  C L C L  O) -(-> +->  o  10H  0  10  100  1000  '  10000  Cu in whole-rock (ppm) FIGURE 69:  Relationship between t o t a l Copper in whole-rocks and biotites  281  The consistent tendency f o r lower Ni, Co, Zn, Mg and Mn levels i n anomalous than background samples cam be explained by leaching of these elements during hydrothermal and mineralization processes. This relationship corroborates f i e l d and bedrock geochemical evidence (Chapter 6) i n which the aforementioned elements are leached from central zones of intense hydrothermal a c t i v i t y and concentrated at the outer margins of mineralized zones. ( i i ) Magnetites Magnetites from anomalous samples are characterized by enhanced Cu values relative to background samples (Fig. 70).  Similar  results have been reported by de Grys (1970) f o r magnetites associated with Cu-bearing intrusions i n Ecuador. magnetite may occur i n two formss ite;  In mineralized environments,  ( l ) as accessory primary magnet-  and (2) as epigenetic magnetite, intimately associated with  sulphide phases. Hewett (1972) undertook a mineralographic study of ore samples from Highland Valley porphyry Cu deposits.  His results  suggest that epigenetic magnetite i s present i n a l l the deposits, and that i t i s usually the f i r s t mineral i n the paragenetic sequence of ore formation. Several of the photomicrographs presented by Hewett (1972) show inclusions of bornite i n epigenetic magnetite. In t h i s study no attempt was made to separate the two types of magnetite and the enhanced Cu content of magnetites from anomalous samples might simply reflect the epigenetic component as indicated by the results of sulphide-selective digestion (Fig. 59).  282  +  Highly Anomalous Samples  o  Weakly Anomalous samples Background samples  r = 0.78 n = 26  100 0 0  IOOOH  •  + •+  +  t  •  100'  IOH  , o  FIGURE 70:  10  100  1000  10000  Cu in Whole Rock (ppm) Relationship between Copper contents of whole rocks and magnetites.  283 Levels of Zn and Co are consistently lower i n anomalous than background samples. This i s suggestive of leaching of these elements from magnetite during hydrothermal alteration. ( i i i ) Quartz-Feldspar Anomalous Cu and relatively low Zn values are characteristic of quartz-feldspar fractions from mineralized samples (Table LIX). As demonstrated e a r l i e r , enhanced Cu values are not due to contamination by biotite or magnetite.  The strong positive correlation  between Cu i n whole rock and quartz-feldspar fractions reflects the high modal proportions (more than 80$) of these minerals i n whole rocks (Fig. 71). Several workers (Azzaria, 1963;  Bradshaw, 1967; 3radshaw and :  Stoyel, 19685Rabinovich and Badalov, 1968) have shown that quartz and feldspars i n fresh granites contain appreciable Cu, although i t s mode of occurrence i s not well understood.  I t may substitute  f o r Fe and Mg, which commonly occur as impurities i n feldspars of unmineralized igneous rocks (Wager and Mitchell, 1951)i c r occur directly as an impurity i n quartz (Cutitta et a l . , i960). Results of sulphide selective leach suggest that Cu i n anomalous samples principally occurs i n sulphide form, mainly as inclusions i n s e r i c i t i z e d plagioclase and K-feldspar  f  Primary quartz probably contains l i t t l e or no Cu, although hydrothermal quartz veinlets commonly carry opaque inclusions which may be sulphides.  284  •  Background samples Weakly anomalous samples  • .j.  Strongly anomalous samples  r = 0.94 n = 26  + + + •  •  • •  +  n  •t  !0  • •  •  100  1000  10000  Cu i n Whole Rock (ppm) FIGURE 71:  Relationship between Copper contents of whole rocks and quartz-feldspar f r a c t i o n s .  285  (iv) Nature of Mineralizing and Hydrothermal  Processes  From the foregoing discussion, i t i s apparent that hydrothermal processes have produced pervasive enhancement i n Cu content of most mineral constituents i n mineralized rocks. This i s i n accordance with the model of mass flow of ore-forming solutions through grain boundaries, pores and other discontinuities i n rocks (Korzhinskii, 1968). The overall effect of these processes i s enrichment of Cu i n most rock constituents.  Results of mineral  analysis further suggest that hydrothermal processes involve leaching of N i , Zn, Mn, Co and Mg from femic minerals. This represents the incipient stage of large-scale metasomatic leaching documented i n the analysis of whole rocks (Chapter 6), which culminates i n the destruction of femic s i l i c a t e s and subsequent formation of hydrothermal alteration minerals. The leached metals are ultimately deposited at the periphery of mineralized zones by outward migrating solutions.  These processes are further discussed i n relation to  genesis of mineralization i n Chapter 8. GEOCHEMICAL CONTRAST Average geochemical contrast f o r Cu between background and anomalous samples i n whole rock and mineral fractions i s summarized in Table LXIII.  KCIO^-HCI digestion gives the best contrast i n  whole-rock analysis.  Compared to whole-rock samples, a l l mineral  phases give lower geochemical contrast for t o t a l and p a r t i a l extractable Cu.  Geochemical contrast i n b i o t i t e i s higher than that  of quartz-feldspar, and contrast i n both mineral phases considerably  286 TABLE LXIII:  Comparison of geochemical contrast in whole rock and mineral separates (26 samples).  HF-HClCv-HNO Total Cu (p.p.m.)  KC10--HC1 Ext. H^O - Asc. Ext.Aqua Regia Cu (p.p.m.) Cu (p.p.m.) Ext. Cu (p.p.m.)  W<0--HC10^ Ext. Cu (p.p.m)  (a) WHOLE ROCK  R °«B  6 - 4585 •  Threshold GM,  A  3 - 1435  4 - 4963  11  14  19  16  90  7  85  107  86-  697  568 .  721  618  9.8  6.7  6.7  7.2  8.3  (b) BIOTITE R  44 - 5617  GM  92  B  Threshold GM  295 1624  Av. Contrast  26 - 5092  18-4253  34 - 4305  82  67  99  324  309  351  1483  1675  1535 4.8  5.5  • 4.8  4.8  (c) QUARTZ-. FELDSPAR R -  12 - 3465 G  K  29  3  Threshold GK  146  A  Av. Contrast  12 - 2605  7 - 1570  21  18  103  101  619  434  4.2  4.2  419  4.1  11 - 3292 24  127 527  4.2  (d) MAGNETITE R  14 - 1061  GM  35 - 5451  35  67  Threshold  101  198  GM.  176  401  1.7  2.0  B  A  Av. Contrast  R = Complete range  GMig = Geometric mean;  Threshold = GM„ + 2 Standard Deviation  a  4 - 4040  21  745  Av. Contrast  2 - 4281  background, anomalous  Av. Contrast = GM./threshold A  287  exceed that of magnetite.  In view of greater contrast obtained  with whole-rock analysis, and d i f f i c u l t y of preparing mineral separates, their use appears to offer :no advantages f o r mineral exploration i n the Highland Valley. SUMMARY AND CONCLUSIONS (1) Cu contents of b i o t i t e , magnetite and quartz-feldspar fractions strongly correlate with whole-rock. This reflects the pervasive effect of epigenetic mineralization processes.  Results  of sulphide-selective leach suggest that significant amounts of Cu are present as sulphides i n a l l mineral phases, from both anomalous and some background samples. (2) With the exception of K-feldspar, modal proportions of minerals i n whole rocks show no consistent relationship with traceelement contents.  The inverse relationship between K-feldspar and  whole-rock Cu_reflects the increasing destruction of K-feldspar as intensity of mineralization increases. (3) Levels of Mg, Ni, Zn, Mn and Co i n biotites and Zn and Co i n magnetites . are consistently lower i n anomalous than background samples. This i s consistent with incipient leaching of these elements during hydrothermal  processes.  (4) Greater contrast was obtained with whole-rock than mineral analysis.  Consequently, the use of mineral separates offers no  advantages f o r mineral exploration i n the Highland Valley.  288a  PLATE 1 3 :  Disseminated sulphide grains (mainly "bornite with minor chalcopyrite) i n mineralized samples at Highmont (reflected l i g h t ) .  PLATE Ik: Bornite inclusions i n chloritized b i o t i t e (a) transmitted l i g h t (b) reflected l i g h t . PLATE 1 5 :  Opaque grains .(sulphide) occuring at the margins of a chloritized b i o t i t e (transmitted l i g h t ) .  288  fc  CHAPTER EIGHT ORE-FORMING PROCESSES AT HIGHLAND VALLEY  290  INTRODUCTION (a) General Statement In recent years numerous genetic models have been proposed f o r porphyry copper deposits (Burnham, 1967; Meyer and Hemley, 1967; Fournier, 1967i Nielsen, 1968; 1970;  White, I968;  P h i l i p s , 1973).  Lowell and Guilbert,  Most of these models have not  benefited from results of detailed bedrock geochemistry, which i n conjunction with experimental studies are crucial to the understanding of chemical aspects of ore-forming processes i n porphyry coppers. The purpose of this portion of the study i s to discuss ore-forming processes at Highland Valley i n relation to lithogeochemical and isotopic data. Some suggestions on the physical aspects of ore genesis are speculative, and more definite conclusions must await results of extensive f l u i d inclusion studies underway at the University of Alberta (R.D. Morton, pers. comm.) (b) Ore Genetic Models f o r Porphyry Copper Deposits Various genetic models have been presented f o r porphyry copper deposits.  A l l these models recognize the importance of mag-  matism i n hydrothermal processes, and the main differences are i n the depth of intrusion, the timing of hydrothermal processes and source of mineralizing f l u i d s (Lowell and Guilbert, 1970). In the orthomagmatic models (Burnham, 1967; Nielsen, 1968) an aqueous-rich v o l a t i l e phase i s released from the magma when internal  291  vapour pressure associated with saturation exceeds l i t h o s t a t i c pressure, or when the intrusive system i s subjected to external stresses.  Within t h i s model, two different sources of ore metals  have been advocated.  Nielsen (1968) among others, suggests that  metals were derived by differentiation of Cu-rich magma. In contrast, Noble (1970) and S i l l i t o e (1972) advocate a deep-seated source f o r ore metals, and consider the role of igneous intrusion i n mineralization to be merely one of structural control rather than a source of ore metals.  At the other end of the ore genetic 'spec-  trum' to the orthomagmatic models, White (1968) postulates an almost completely external source of mineralizing f l u i d s - connate and/or meteoric hydrothermal solutions subject to convective processes by heat generated by subjacent intrusions.  In t h i s model,  the pluton plays a passive role i n mineralizing processes. Various lines of evidence suggest that close relationships between mineralization at Highland Valley and evolution of the Guichon Greek batholith (Northcote, 1969; Brabec and White, 1971). Firstly," most of the major porphyry copper deposits are spatially associated with the younger and most differentiated rock units of the batholith - Bethsaida and Bethlehem Phases. Secondly,isotopic age determinations indicate temporal relationship between magmatism and hydrothermal processes.  Results of K-Ar age determinations on  hydrothermal s e r i c i t e s and biotites (Blanchflower, 1972; Jones et a l . , 1972; Dirom, 1965) indicate that, within l i m i t s of analytical error, mineralization and emplacement of the batholith are contemporaneous.  292  Despite the close spatial and temporal relationships between mineralization and evolution of Guichon Creek batholith, i t i s not clear whether the role of the pluton i n mineralization i s one of structural control or as a direct source of metals. ORIGIN OF GUICHON CREEK BATHOLITH AND SOURCE OF METALS One of the important tenents of the orthomagmatic model i s that ore-forming f l u i d s are by-products of magmas of the associated intrusion.  I f this supposition i s correct, then the  origin of Guichon Creek batholith i s pertinent to ore genesis at Highland Valley.  Relevant geochemical and isotopic data are reviewed  i n the following section. (a) Provenance of Guichon Creek Magma and Associated Metals Numerous workers have shown that K/Rb and Rb/Sr ratios set important constraints on the source materials of igneous masses (Hurley,  I968;  Culbert, 1972). Results of regional geochemistry  indicate that K/Rb ratios i n rocks of the Guichon Creek batholith are relatively high (mean = 358) and largely outside the l i m i t considered normal for continental plutonic rocks (Fig. 72). Furthermore, the Rb/Sr ratios are low and primitive, plotting i n the region of basalts and andesites (Fig. 73).  The mean Rb/Sr  ratio of 0.05 i s one-fifth the value cited for s i a l i c crust (0.25; Faure and Hurley, I 9 6 3 ) . 87  batholith i s changing i t s Sr '/Sr Rb ') by only .001 every 500 m.y. nature.  Thus the copious Sr i n the 86 ratio (by radioactive decay of This reflects i t s primitive  Compared with other Mesozoic plutons i n the Intermontane  FIGURE72:  50  Hot  ^^ ^^5^^^r u  Rb (  **• 500' —  c™* iv  294  •  Guichon rocks  ^ . A v e r a g e S i e r r a Nevada g r a n i t i c rock  FIGURE 73:  Sr (ppm) P l o t of Rubidium versus Strontium in rocks of Guichon Creek b a t h o l i t h (Generalized geochemical r e l a t i o n s h i p s of Rb and Sr in c e r t a i n types of rocks are shown f o r comparison; a f t e r Hedge, 1966)  295 Belt (Table LXIV), the Guichon Greek batholith i s r e l a t i v e l y impoverished i n Rb and K, and characterized by higher K/Rb lower Rb/Sr ratios.  and  However, values obtained f o r the Guichon Greek  batholith are similar to those reported by Gulbert (1972) f o r the Coast Mountains batholith of the Coast Mountains Belt.  The r e l a t i v e l y  high K/Rb and low Rb/Sr ratios i n rocks of Guichon Creek batholith are not due to mineral fractionation, but reflect derivation from a subcrustal source region depleted i n a l k a l i s and enriched i n Sr, most probably from subducted oceanic crust or upper mantle.  This  interpretation i s consistent with the primitive i n i t i a l Sr isotopic ratio ( S r / S r 8 7  8 6  = 0.7037) reported by Chrismas et a l . , (1969)  Monger et a l . (1972) and Dercourt (1972) have presented tectonic models f o r the evolution of the Canadian Cordillera which suggest that the Intermontane Belt, comprising extensive andesitic volcanic rocks and calc-alkaline plutons (including the Guichon Creek batholith), was the s i t e of an ancient island arc generated by subduction of oceanic crust of the P a c i f i c Plate beneath continental crust of the overriding North American Plate during the Mesozoic. In accordance with t h i s model, the r e l a t i v e l y early Mesozoic age of the Guichon Creek batholith - the oldest-dated Mesozoic pluton i n the Canadian Cordillera - and i t s low K>Q content (mean = 1,85$) suggest derivation of the batholith from r e l a t i v e l y shallow depths from the subduction zone (calculated as <130 km; Dickinson, 1969) close to the Triassic trench.  Hatherton and  In t h i s context, the  low a l k a l i s i n the batholith, high K/Rb and low Rb/Sr ratios are consistent with derivation from hydrated oceanic crust of probably  TABLE LXIV,  •Means and ranges of Rb, Sr, Rb/Sr, K/Rb and S r  8 ?  /Sr  8 6  r a t i o s i n some Mesozoic Cordilleran intrusions.  Intrusions  Rb (p.p.m.)  Simllkameen  95  batholith  (52 - 152)  Hogem batholith  390 (11*7 - 639)  80 (55 - 118)  (468 - 1520)  K/Rb  0.151  250  0.100  430  (0.041-0.125)  (322 - 502)  Sr ?/Sr 8  (m.y.)  8 6  0.7060  I83  (0.7029-0.7091) 170'  0.175  batholith  batholith  Rb/Si  (0.081 - 1.01) (1?2 - 309)  730  Kelson  White Creek  Age  Sr (p.p.m.)  171 - 49  (O.O56.- 0.483) 265  804  (196 - .,357)  (435 - 1118)  0.7069  0.412  °-7250  (0.108-1.655)  0.246  0.7081  (0.115 - O.357) Vemon  (0.7072-0.7090)  1.42  batholith 33  batholith  (* - 150)  Guichon Creek  35  batholith  (3 - 132)  •  725  (25 - 795) 686 (249-1000)  •Modified a f t e r Peto (1974)  0.046  1  1  8  '  1  55 373  (0.11 - 0 . 6 0 ) (225 - 628) O.05  '  0.7064  (0.108-2.84)  Coast Mountains  m  (O.7076-O.7397;  Bayonne batholith  ^  0.7038 (0.7031-0.7050)  140, 84  358  (0.004 - 0.321) (132 - IO30)  0.7037  200 -  5  1  0  297 amphibolite composition (Jakes and White, 1970).  Furthermore,  results of sulphur isotopes i n hydrothermal sulphides and sulphates, and deuterium and oxygen isotopes i n hydrothermal sericites and kaolinites (Field et a l . , 1973! Jones et a l , 1972?  Sheppard et a l . ,  1969) suggest a subcrustal source f o r mineralizing solutions and associated metals. (b) Level of Emplacement and Volatile Pressures Northcote (19^9) has presented geologic evidence which suggests that the older intrusive units within the batholith were emplaced under mesozonal conditions, whereas the younger units, that are spatially associated with mineralization, were emplaced at r e l a t i v e l y shallower levels i n the crust (epizone). Westermann (1970), investigating the c r y s t a l l i z a t i o n history of the batholith, found that i n the older rock units, plagioclase crystallized e a r l i e r than quartz, whereas i n the younger Bethlehem-Skeena and Bethsaida Phases, quartz was f i r s t to c r y s t a l l i z e .  Moreover, the quartz  grains i n the younger and more differentiated units are commonly fractured and occur dominantly as phenocrysts.  According to  Westermann (1970)$ these textural and mineralogical features are suggestive of increasing v o l a t i l e  pressures within the magma.  A rough estimate of v o l a t i l e pressures during c r y s t a l l i z ation of the most differentiated and youngest unit (Bethsaida Phase) can be obtained by projecting normative compositions into the experimental system Ab-Or-Qz-HgO (Fig. 7*0. A l l five samples of Bethsaida rocks plot i n a restricted area close to the isobaric thermal trough f o r water vapour pressures around 6 to 7Kb.  On the basis of  Witches Brook Phase Bethsaida Phase Average Norms i Hybrid 21 'Chataway Guichon Bethlehem Skeena Witches Brook Bethsaida Bethlehem Porphyry Gnawed Mountain  FIGURE 74:  Plot of normative Ab-Or-Qz proportions f o r the Guichon Creek . samples compared with boundary curves and minima at 2,4,7 and 10 Kb P (von Platen and H o l l e r , 1966) Ab/An r a t i o = 2.9 H  Q  ro oo  299  textural and f i e l d evidence Northcote (1969) has suggested that the Bethsaida Phase crystallized at r e l a t i v e l y shallow depth (epizone), thus implying, at most 6 to 8km df cover which would produce a load pressure of about 2kb. I f these estimates are correct, then the v o l a t i l e pressures existing during emplacement of the Bethsaida Phase may be estimated as k to 5kb. Burnham (196?) has suggested that the maximum content of HgO i n a granodiorite magma i s about 6 wt. %, most of which i s exsolved ('boiled off') between 10km and 3km depths.  However at  shallower depths, v o l a t i l e pressures i n excess of load pressure and tensile strength of the confining rocks may result i n the development of shear fractures and micro-brecciation of cover rocks, permitting escape of 'fecund' aqueous solutions to form ore deposits. The porphyritic texture and fractured quartz phenoczysts i n rocks of Bethsaida Phase (Westermann, 1970), and the presence of breccia pipes, are consistent with increasing v o l a t i l e pressures during magmatic differentiation,  However, no textures indicative of retro-  grade boiling h&vle so f a r been documented, probably because of the d i f f i c u l t y of differentiating them from similar hydrothermal features (Philips, 1973). From the foregoing discussion, i t i s evident that magmatic evolution of the batholith created the suitable structural and chemical environment f o r localization of mineralization within the batholith.  300  NATURE OF ALTERATION-MINERALIZATION PROCESSES Extensive wall-rock alteration, that i s so characteristic of porphyry copper deposits, constitutes the most v i s i b l e evidence of interaction between host rocks and hydrothermal solutions. Meyer and Hemley (196?) among others, have demonstrated the close temporal and genetic relationships between sulphide deposition and wall-rock alteration at porphyry copper deposits. (a) Mineral S t a b i l i t y Fields Mineralogy of alteration assemblages at Highland Valley deposits provides evidence of the composition of mineralizing f l u i d s . A l l the deposits of the Highland Valley contain s e r i c i t e alteration either i n association with kaolinite, quartz or K-feldspar. A r g i l l i z a t i o n and s e r i c i t i z a t i o n of wall rocks require slight to moderate acidity (pH<6) whereas abundant K-feldspar suggests pH exceeding 7 (Barnes and Czamanske, 196?). Cross-cutting vein relationships suggest that K-feldspar with.or without quartz i s generally early i n the paragenetic sequence, and followed by s e r i c i t e and a r g i l l i c veins or selvages.  This sequence suggests increasing  a c i d i t y of hydrothermal f l u i d s with increasing evolution. However, at Valley Copper, K-feldspar envelopes occur around s e r i c i t e veins and i n equilibrium with kaolinite.  This relationship, which i s  contrary to the s t a b i l i t y - f i e l d relationships established f o r these minerals by Hemley and Jones (1964), i s attributed to a resurgence of abnormally high s i l i c a a c t i v i t i e s i n ore-forming f l u i d s s h i f t i n g the mineral s t a b i l i t y f i e l d to higher pH levels.  (b) Bedrock Geochemical Evidence  301  Results of bedrock and mineral geochemistry (Chapters 6 and 7 ) suggest that widespread chemical changes i n wall rock are intimately associated with mineralization and hydrothermal a l t e r ation.  Each deposit i s characterized by central mineralized zones  i n which metasomatic a c t i v i t y i s most intense. In zones of intense a r g i l l i c and p h y l l i c alteration at Valley Copper, Lornex and Highmont, the base elements Ca, Na, Sr, Ba, Zn, Mn, Mg and Fe are depleted, whereas i n potassic zones at the JA, Lornex and Valley Copper deposits K, Rb and Ba are relatively enriched.  Calculations of chemical gain and loss of principal rock  constitutents through alteration and mineralization at Valley Copper (Fi . 75)» suggest that i n quartz-sericite and potassic zones, Ca, Mg, Fe, Na and A l are removed and K, Si and S added (for method of calculation, see Gresens, I 9 6 7 ) .  The obvious depletion of base  cations i n mineralized and altered zones i s attributed to the break down of ferromagnesian minerals and plagioclase to s e r i c i t e and kaolinite.  Incipient stages of the above process are demonstrated  by results of mineral analysis. Zn, Mn, Mg and.'Go levels i n biotites and magnetites are consistently lower i n mineralized and altered than i n fresh samples.  Cu and S concentrations, though e r r a t i c ,  are highest i n zones of intense alteration and metallization, decreasing outwards to back round levels i n fresh unmineralized host rocks. DISCUSSION The following modes of o r i g i n have been proposed f o r porphyry copper deposits, hence are relevant to the genesis of the  Si  Al  Fe  Mg  Ca  Na  200  S  o  o o  21  "> <fi a-  O 100 20CH  [ Ul  | Argillic (kaolinite + sericite icalcite) Phyllic  (quartz + sericite ± K-feldspar)  fTT|j Potassic  FIGURE 75:  Gain and loss of p r i n c i p a l rock constituents Valley Copper 3600 l e v e l .  through a l t e r a t i o n and m i n e r a l i z a t i o n .  o  !\3  303 Highland Valley deposits. ( i ) Extraction of ore metals either by leaching of wall rocks by convecting meteoric waters as proposed by White (1968), or by deuteric alteration as proposed by Putman (1972). ( i i ) Derivation of ore metals by assimilation of country rocks (Schau, 1970). ( i i i ) Concentration of ore metals by differentiation of a Cu-rich magma (Brabec and White, 1971. Nielsen, 1968; Burnham, 1967;  Graybeal, 1973). /  F  (iv) Derivation of ore metals by p a r t i a l melting of subducted oceanic crust, and subsequent transportation to crustal levels, as an independent phase within calc-alkaline magmas ( S i l l i t o e , 1972;  Mitchell and Garson, 1972; Wright and McCurry, 1973;  Noble, 1970). On the basis of variations of Cu contents i n the Guichon Creek batholith, Brabec and White (1971) postulated that the Highland Valley deposits were derived by differentiation of a Cu-rich magma. In contrast, Schau (1970) has suggested that Cu i n the batholith was derived by assimilation of Nicola volcanic rocks. A l l the a l t e r natives are now considered i n l i g h t of regional, detailed bedrock and mineral geochemistry, and isotopic data. The f i r s t hypothesis i s least l i k e l y because results of detailed bedrock geochemistry around mineralized zones indicate that no zone of Cu and/or S depletion surrounds the orebodies at the l e v e l  304 of sampling, although the remote p o s s i b i l i t y that these elements could be extracted from channelways at greater depths i s not ruled out.  Moreover, results of mineral geochemistry suggest no obvious  leaching of Cu from b i o t i t e s , although such leaching of Zn, Mn, N i , Co and other 'femic' elements i s apparent i n bedrock and minerals. The second hypothesis has been proposed by Schau (1970) who postulated that ore metals were derived by assimilation of Nicola volcanic rocks.  Brabec and White (1971) have c r i t i c i z e d this  hypothesis by demonstrating that the Hybrid Phase, the most contaminated unit within the batholith, i s not significantly higher i n Cu than uncontaminated rocks of the Guichon and Chataway Phases.  Brabec  (1970) further suggests that the relatively high Cu levels i n the batholith would require selective assimilation of this metal from a large volume of country rocks. F i e l d evidence do not support a large-scale contamination of the batholith beyond the outer margins (Northcote, I969). Available geochemical data are not consistent with the third hypothesis proposed by Brabec and White (1971)» since ( i ) Cu i n association with Zn, Mn, T i , V, Ni, Co, Fe and Mg generally decrease^ with increasing fractionation or f e l s i c composition of intrusive units.  This geochemical pattern simply reflects normal  differentiation trends observed i n unmineralized intrusions.  Sheraton  and Black (1973)» investigating trace element geochemistry of granitic intrusions unmineralized with respect to Cu, found that Cu concentrations decreased from more than 40 p.p.m. i n granodiorite to less than 5 p.p.m. i n more differentiated granites.  In contrast,  305  studies on intrusions that are known to have generated immiscible sulphide- phases such as the Skaergaard (Wager and Brown, 1967)» and mineralized Laramide intrusions i n Arizona (Graybeal, 1973)» Cu contents of bedrock and mineral constituents generally increase with differentiation u n t i l Gu separates from the melt  as.ian  immiscible  sulphide phase. Graybeal (1973)» investigating the partitioning of Cu between co-existing b i o t i t e and hornblende found that, under equilibrium conditions, higher concentration  of Cu within the magma  was reflected by higher concentrations i n the mineral phases. In the Guichon Creek batholith, results of Cu determinations i n biotites and hornblendes (Brabec, 1970) suggest no appreciable variations throughout the batholith. From the foregoing discussions i t i s apparent that geochemical data do not support the hypothesis that ore metals at Highland Valley were derived by differentiation of a Cu-rich Guichon Creek magma. On the contrary, i t i s argued that the Guichon Creek magma became increasingly impoverished i n Cu as a result of differentiation. The fourth hypothesis, which regards mineralization as an independent by-product of magma generation rather than a direct result of differentiation processes, i s consistent with geochemical data and i n line with contemporary ideas of plate tectonics and ore genesis.  Nevertheless, i t must be emphasized that differentiation  processes within a magma, provide the right chemical and physical environment f o r localization of ore metals. High K/Rb and Sr values and low Rb, K, Rb/Sr and Sr isotopic ratios are consistent with derivation of Guichon Creek magma  306 from a deep-seated source, most probably subducted oceanic crust or upper mantle.  Results of sulphur, oxygen and deuterium isotopes  suggest a similar deep-seated source f o r mineralizing solutions and ore metals. Because of the temporal and spatial relationships between mineralization and magmatism, i t i s l o g i c a l to presume that ore metals at the Highland Valley deposits were derived from a metal-rich portion of the subducted oceanic crust from which the Guichon Greek magma was generated. S i l l i t o e (1972) has demonstrated that there i s enough Cu i n oceanic basalts to generate metals i n ore deposits.  The ore metals derived from p a r t i a l melting of sub-  ducted oceanic crust probably occur i n a sulphide phase independent of the magma. Thus the role of the magma i s believed to be one of structural control i n channeling ore metals to crustal levels (Noble, 1970). Nevertheless, differentiation of the magma provided v o l a t i l e s and structural openings, such as fractures, breccia zones, dyke swarms that f a c i l i t a t e d the extraction of metals from the system and concentration as ore deposits. Fig. 76 shows a comprehensive model that explains the evolution of the ore-forming f l u i d s at the hydrothermal stage. The close spatial relationship between porphyry dykes or dyke swarms and ore deposits at Highland Valley, suggests that porphyries served as high-level structural 'outlets' f o r mineralizing solutions. The presence of saline f l u i d inclusions i n quartz veins at Valley Copper Lornex and Highmont (R.B. Morton, pers. comm.) and enhanced values of B, F, Cl and S i n ore zones suggest that the mineralizing f l u i d s contained HC1, H^BO^, HF, HgS, HgSO^ and other v o l a t i l e elements.  EVOLUTIONARY PATH OF FLUIDS  CHEMICAL ZONING  SULPHIDE  <rt7777T////////// Pyrite • Chalcopyrite  ZONING  Bornite  ALTE R A T I O N ZONING  <3333>Tourm. <CS33><XS> Qtz. «fTro>K-Fi , -rrmrr -VTV,\\W Montm. P  ALTERATION  TYPE  Pot. |Arg. Ser  Propylitic  \ CUT Mo, K etc  H2S,  FIGURE 76:  Model f o r chemical and mineral zoning and evolution of ore forming f l u i d s .  308  Late stage differentiation products, such as K", S i 0 , Rb and Na^ T  2  were probably present.  Extensive a r g i l l i c and sericite alteration  found around the deposits require that ore solutions be s l i g h t l y to moderately acidic, and contain abundant H , probably derived from +  dissociated HgO and HgS present i n the juvenile f l u i d s , or by admixture with convecting meteoric waters generated by heat from the porphyry dykes or stocks. Helgeson (1970) has presented thermodynamic data which demonstrate that a l l e q u i l i b r i a i n hydrothermal systems can be represented i n terms of the ratio of a c t i v i t i e s of cations i n the aqueous phase to that of the hydrogen ion. Changes i n base cation/ H a c t i v i t i e s as ore-forming f l u i d s transgress the alteration zones +  are portrayed i n F i g . 76.  The evolutionary paths, designated 1, 2  and 3 i n the diagram, represent different degrees of equilibration between ore fluids and wall rock. zone (K-feldspar - quartz  Formation of an early potassic  - s e r i c i t e ; , that i s commonly centred on  porphyry dykes, requires a high base cation (K , Na )/H a c t i v i t y +  +  +  ratio which could result from i n i t i a l composition of mineralizing f l u i d s (inherited from the magma) or less probably be derived at depths by H  +  consuming and base cation-releasing equilibrium reactions.  As the ore f l u i d s rise and spread outwards they undergo adiabatic expansion, and i n conjunction with reaction with wall rocks and/or mixing with meteoric waters, cool, causing dissociation of the most acidic components. This dissociation provides most of the abundant H  +  required f o r hydrolitic base leaching within the  quartz-sericite and a r g i l l i c zones, under acidic conditions. The  309  base cations (Mg"*"**, Ga , Fe"* ", Na , Sr" ", Ba , Zn**, Mn ), ++  -1  +  4-1  +  ++  released by leaching, are taken into the f l u i d and transfered to the outlying metasomatic front (Korzhinskii, 1968), as the solutions are cooled and neutralized. Changes i n base cation/H  +  a c t i v i t y ratios are generally  accompanied by changes i n pH and sulphur fugacity (Meyer and Hemley, 1967) which ultimately control sulphide deposition and zoning patterns. This accounts f o r the close association between s e r i c i t e and a r g i l l i c alteration, which require H consumption i n t h e i r formation and +  sulphide mineralization,as amply demonstrated at Valley Copper, Lornex, Highmont and i n parts of Bethlehem-JA. From the foregoing discussion, i t i s apparent that regional, detailed bedrock and mineral geochemistry,and isotopic and tectonic evidence are consistent with the mode of origin proposed f o r the Guichon Creek batholith. Assuming the genetic model correct, i t has far reaching implications i n reconnaissance exploration f o r Cu deposits i n calc-alkaline intrusions of the Intermontane Belt. F i r s t l y , the apparent negative correlation between Cu contents and ore potential of the Guichon Greek batholith suggests that ore-bearing intrusions w i l l probably not be enriched i n Cu.  Thus the suggestion  by Warren and Delavault, (i960) that high Cu contents of intrusions reflect ore potential might not be generally applicable.  Secondly,  i f ore metals i n the Guichon Creek batholith were derived from subducted oceanic crust as an independent by-product of magma generation, i t i s most plausible that other calc-alkaline plutonic and volcanic rocks of similar age as the Guichon Creek batholith might originate  310  from the same metal-rich portion of subducted oceanic crust. Such calc-alkaline intrusive and extrusive rocks within the Intermontane Belt can be identified by; Early Jurassic);  ( l ) Their ages (Late Triassic -  (2) t h e i r low Rb, Rb/Sr and high K/Rb ratios;  and (3) t h e i r 10,0 content which should reflect the relatively shallow depth of magma generation.  Using the Guichon Creek batholith as a  'reference index', calc-alkaline intrusive and extrusive rocks ..which meet the above c r i t e r i a might have considerable potential f o r porphyry Cu and/or massive sulphide deposits. CONCLUSIONS Regional, detailed bedrock and mineral geochemistry of the Guichon Creek batholith and associated mineralization i s consistent with the hypothesis that ore metals did not arise as a direct result of differentiation processes within a Cu-rich magma, but rather as an independent by-product of magma generation from subducted oceanic crust of probably amphibolite composition.  Neverthe-  l e s s , chemical and mineral fractionation within the Guichon Greek magma led to the development of increased v o l a t i l e contents and pressures that provided suitable chemical and structural environments f o r l o c a l i z a t i o n of ore deposits. Consequently not a l l ore-bearing plutons need be enriched i n Cu.  CHAPTER NINE S U M M A R Y . A N D  CONCLUSIONS  312  SUMMARY AND CONCLUSIONS More than 1500 bedrock and mineral samples collected-"from the v i c i n i t y of four major porphyry copper deposits i n the Highland Valley together with 60 fresh regional samples (Northcote, r.  1968) were analyzed f o r more than 20 major, trace and potential pathfinder elements by t o t a l and p a r t i a l extraction techniques. Results and conclusions are summarized as follows: (a) Regional  Geochemistry  (1) Major element variations i n rocks of the batholith suggest fractional c r y s t a l l i z a t i o n of a calc-alkaline d i o r i t i c magma by progressive fractionation of plagioclase, b i o t i t e and hornblende. By this process, derivative f l u i d s were enriched i n S i and Na, and depleted i n Ca, Fe, Mg and T i . Ca-Na-K variation diagram indicates two trends of differentiation;  normal calc-alkaline trend associated  with K enrichment i n dyke rocks of the Witches Brook Phase, and a trondjhemitic trend associated with Na enrichment in the remainder of the batholith. (2) In general, the batholith i s r e l a t i v e l y impoverished i n KgO and Rb (mean values 1.85% 10,0;  35 p.p.m. Rb), and charac-  terized by high K/Rb and low Rb/Sr ratios. sistent with primitive i n i t i a l S r / S r 8 7  8 6  These results are con-  ratio (0.7037; Chrismas  et a l . , 1969) suggesting derivation of the magma from the upper mantle or subducted oceanic crust, i n accordance with plate tectonic models.  313  (3) Variations i n Mn, Zn, N i , Go and V are intimately associated with degree of fractionation.  These elements were pro-  ressively depleted i n the Guichon Greek magma with increasing magmatic differentiation.  Strong positive correlations with Fe and  Mg suggest partitioning of these femic trace elements into s i l i c a t e fractions during magmatic evolution. (4) In accordance with results obtained by Brabec (1970), Cu concentrations decrease progressively from the relatively older and more mafic, to r e l a t i v e l y younger and more f e l s i c units. Minimum concentrations are encountered i n the Bethsaida and Gnawed Mountain Phases that are spatially associated with Cu mineralization. The apparent tendency f o r Cu to decrease with increasing d i f f e r entiation i s commonly characteristic of unmineralized intrusions, and suggests that the  Guichon Creek magma was probably not the  direct source of metals concentrated by differentiation.  This i s i n  disagreement with the model proposed by Brabec (1970) and Brabec and White (1971), rather, i t seems differentiation depleted the magma of metals. (b) Detailed Bedrock Geochemistry (5) Variations i n concentrations of the 'femic group' of metals (Zn, Mn, T i , V, Fe and M ) around mineralization are cont r o l l e d principally by primary l i t h o l o g i e s .  This i s consistent  with the geochemical a f f i n i t y between these trace elements and Fe and Mg. However, i t i s apparent that i n deposits where there i s only one major host rock, such as at Valley Copper and Lornex,  314  Zn, Mn, Fe and Mg are leached i n zones of intense a r g i l l i c and phyllic alteration.  This i s attributed to the complete breakdown  of ferromagnesian minerals to s e r i c i t e and kaolinite.  In contrast,  propylitic zones with abundant chlorite, epidote, pyrite and carbonate are generally associated with enhanced values of femic metals• (6) The lithophile elements Sr, Ba, Ca and Na are consistently depleted i n zones of intense hydrothermal a c t i v i t y , especially where i t s character i s phyllic or a r g i l l i c .  In con-  t r a s t , Rb, K and less commonly Ba are enriched i n zones of Kfeldspar and s e r i c i t e alteration.  Rb/Sr and Ba/Sr ratios show  consistent patterns related to alteration and mineralization, (7) Cu and S, though e r r a t i c , show the highest contrast) and halos extending at least 0.5km from the «ore zones, and beyond v i s i b l e alteration envelopes.  Of these two elements, S seems to  be less e r r a t i c than Cu as demonstrated by r e l a t i v e l y lower coe f f i c i e n t s of variation.  Furthermore, dispersion trends f o r S are  more consistent and smoother, partly because S occurs not only as Cu sulphides but also i n pyrite which i s most commonly disseminated at the periphery of porphyry-type deposits. (8) Hg dispersion i s not consistent at Highland Valley} broad and pronounced halo i s associated with Bethlehem-JA but i s absent at Valley Copper. This behaviour i s attributed to either higher temperature of ore formation or the clay and s e r i c i t e  a  315  composition of alteration minerals at Valley Copper, which resulted i n the loss or escape of v o l a t i l e Hg. (9) B anomalies are well developed at lornex and Highmont, partly as a result of the s p a t i a l association of mineralization with tourmaline-bearing breccia pipes and porphyry dykes.  Never-  theless, i t i s apparent that ore-forming solutions at Highmont and x  Lornex cbnt&B.ned r e l a t i v e l y abundant B.  At Valley Copper and JA,  B anomalies are less prominent. (10)  The halogens (Cl, F ) , either as t o t a l or water-extract-  able, are low in'poncehtrations  and do not show consistent relation-  ship with hydrothermal alteration and/or mineralization.  The  absence of relationship between halogens and mineralization i s most obvious at Valley Copper, and might suggest loss of halogens by volatization.  This i s consistent with results reported by  Kesler et a l . (1972) suggesting no relationship between halogen content of intrusions and t h e i r Cu bearing potential. (c) Mineral Geochemistry (11)  Cu contents of b i o t i t e , magnetite and quartz-feldspar  fractions strongly correlate with whole-rock Cu i n background and anomalous samples.  Results of sulphide-selective leach are con-  sistent with the principal mode of occurrence of Cu as sulphide inclusions i n a l l mineral phases of both anomalous and some backround samples. (12)  Levels of Mg, N i , Zn, Mn and Co i n b i o t i t e s , and Zn  316  and Go i n magnetites are generally lower i n mineralized than background samples. This i s consistent with incipient leaching  of  these elements during hydrothermal alteration. (d) Sulphide Selective Digestion (13)  An efficacious sulphide-selective leach (KG10^-HGl),  not used previously i n bedrock geochemistry, was developed during t h i s study. (14) Experimental results demonstrate that KClCy-HCl leach appears to be more sulphide selective f o r Cu than procedures such as HgCvj-Ascorbic acid and aqua regia digestion. Furthermore, hot concentrated acids are not involved, and the procedure i s extremely rapid and simple and hence suited to routine application both i n the f i e l d and laboratory. (15)  KCIO^-HCI digestion gives a better geochemical contrast  f o r Cu i n bedrock, than either aqua regia, HgOg-Asc, or t o t a l digestion. (16)  As expected, distribution of sulphide-held Cu using  KC10^-HC1 digestion at Valley Copper and JA i s s i m i l a r to that of t o t a l Cu because of the dominant occurrence of Cu as sulphide veins and disseminations. halos surrounding  However, sulphide-held Fe delineates pyrite these deposits. •  (e) Ore-forming Processes at Highland Valley. (l?) In view of established spatial and temporal relation-  317 ships between mineralization at Highland Valley and the evolution of the Guichon Greek magma, a modified orthomagmatic model i s proposed f o r ore genesis at Highland Valley. (18) Results of K, Rb and Sr determinations indicate r e l a t i v e l y low abundances of these elements i n fresh rocks of Guichon Greek batholith compared with other Mesozoic granitic rocks i n the Canadian Cordillera.  K/Rb ratios are r e l a t i v e l y high, and  largely outside the l i m i t s considered normal f o r crustal plutonic masses of grantic composition.  Rb/Sr ratios are\  ?low,  and similar to values reported f o r t h o l e i i t i c and 'primitive' calcalkaline rocks of ancient island arcs. These results are consistent with low Sr isotopic ratios reported by Chrismas et a l . (1969), and suggest derivation of the batholith from a subcrustal source, most probably from subducted oceanic crust or upper mantle. (19) A deep-seated source of the Guichon Creek magma has far-reaching implications f o r ore  genesis. Various lines of  isotopic evidence suggest derivation of sulphur and associated ore metals from a subcrustal source similar to that of the batholith, which i s considered as a metal-rich portion of the subducted oceanic crust.  Distribution of Cu i n the batholith i s similar to  that of other femic elements, i n that i t d i f f e r s from trends observed i n intrusions that are reported to have produced immiscible sulphide phases, such as Skaergaard ( Wager and Brown, 1967)» ri<i a  Laramide porphyritic intrusions of Arizona (Graybeal, 1973). Consequently, i t i s suggssted that the role of Guichon Creek magma  318  i n mineralization i s merely one of structural control rather than a direct source of metals.  However, differentiation of  Guichon Greek magma provided adequate v o l a t i l e s and structural 'traps' that led to the extraction of metals from the 'system'. (20)  Close spatial relationships between mineralization  and prophyry dykes or stocks suggest.that porphyries provided 'high-level' structural outlets f o r mineralizing solutions which subsequently reacted with wall rocks to produce the alteration and chemical patterns characteristic of porphyry-type deposits i n the Highland Valley. (21)  The extensive leaching of 'base elements' (Ca, Na, Sr  Ba) i n zones of phyllic and a r g i l l i c alteration i s consistent with decreasing base cation/H ratios during the intense 'wave' +  of acidic processes associated with formation of H minerals such as s e r i c i t e and kaolinite.  +  consuming  The leached elements  are concentrated at the outer margins of the metasomatic front (Korzhinskii, 1968)  as solutions migrate outwards and are neut-  ralized by reaction with wall rocks. (f) Applications of Bedrock Geochemistry i n Exploration Results of this study suggest that bedrock geochemistry can be very useful f o r reconnaissance and detailed mineral exploration i n the Guichon Creek batholith and similar calc-alkaline intrusions i n the Canadian Cordillera.  319  (22) Assuming that the Guichon Creek magma and associated ore metals were derived from a metal-rich portion of subducted oceanic crust, the following c r i t e r i a can be useful i n reconnaissance exploration f o r Cordilleran intrusive and extrusive rocks generated from the same source region as the Guichon Creek batholith and with potential f o r porphyry coppers and/or massive sulphides, ( i ) Late Triassic to Early Jurassic age;' ( i i ) low K, Rb and Rb/Sr values, and'high.K/Rb ratios;  and ( i i i ) location i n the Inter-  montane Belt of southern Canadian Cordillera. (23) In view of the supposed role of magmatic differentiation i n providing suitable chemical and structural environments f o r ore l o c a l i z a t i o n , petrochemical variation diagrams.can be useful l n identifying intrusive units that.are most fractionated and capable of being spatially associated with mineralization. (24) The close relationships between metal values and degree of fractionation i n the Guichon Creek batholith suggest the need f o r assigning different background values to each intrusive phase and s o i l s derived from them, during  geochemical exploration programmes .  (25) 'For ^detailed exploration around porphyry copper prospects or deposits, Cu and S, because they show high contrast and extensive halos, constitute tools f o r delineating mineralized zones. S, however shows the more consistent or less erratic dispersion patterns.  Pronounced S anomalies i n bedrock suggest that SCv, i n  s o i l gas or a i r can be useful i n o u t l i n i n g mineralized zones at  320 Highland Valley.  The intensity of such halos might be affected  by b o r n i t e c h a l c o p y r i t e ratio;  \  where t h i s ratio i s high  (reflecting higher ore grade), intensity of gas anomalies w i l l be diminished. (26)  Sulphide-held Gu shows a greater contrast than t o t a l  Gu where a large number of fresh background samples are included i n sampling programmes. Sulphide-held Fe as determined by KC10^-HC1 w i l l be useful i n outlining pyrite halos that most commonly envelope prophyry coppers. (27)  In view of the close association between alteration and  mineralization at porphyry coppers, the distribution of lithophile elements Rb, Sr and Ba, and/or K, Ca and Na, constitutes a reliable t o o l i n delineating zones of intense alteration and mineralization. They are easily determined by routine analysis and t h e i r distribution more readily quantified than fine rained mineralo;gy characteristic of alteration zones. Furthermore, the use of ratios (e.g. Ba/Sr Rb/Sr) offer added advantages, i n that i t eliminates the influence of e r r a t i c data or l o c a l mineralogical control on metal distribution.  At High-  land Valley, Rb/Sr and Ba/Sr ratios exceeding 0.1 and 1 respectively delineate mineralized zones. (28) Volatile elements have a limited application to exploration i n the Highland Valley.  Hg i n bedrock, s o i l gas or a i r  can be useful i n detecting orebodies. similar to the Bethlehem-JA deposit.  B i s most useful i n exploring f o r deposits associated with  321 breccia pipes and quartz porphyries.  Because of the absence of  pronounced Gl and F anomalies at the Highland Valley deposits, halogens i n bedrock or as gaseous indicators have no exploration potential i n the Highland Valley. (29) Factor analysis constitutes a potent t o o l i n deciphering the inter-relationships of metal distributions i n multielement geochemical studies.  Metal associations obtained by  factor analysis are consistent with subjective interpretations of geologic, hydrothermal and metallization processes. (30)  Greater contrast was achieved with whole-rock than  mineral analysis, consequently the use of mineral separates offers no advantages f o r exploration i n the Highland Valley.  322  REFERENCES Ager, C.A., Ulrych, J.J., and McMillan, W.J. 1973. A gravity model f o r the Guichon Creek batholith, south-central, B r i t i s h Columbia. Can. J. Earth Sci., v. 10, pp. 920-935. Al-Hashimi, A.R.K. 1969. A study of copper dispersion i n the • Boulder batholith, Montana. Unpublished Ph.D. thesis, Boston University, 144 p. Al-Hashimi, A.R.K., and Brownlow, A.H. 1970. Copper content of biotites from the Boulder batholith, Montana. Econ. Geol., v. 65, pp. 985-992. Allmann, R. and Korting,. S. 1972. Fluorine i n Handbook of Geochemistry, ed. K.H. Wedepohl, v. 3, pp. 9E-9F, Springer Verlag Publishers, New York, Armbrust, G.A., Munoz, J.O., and Farias, J.A. 1971. Rubidium as a guide to ore at E l Teniente (Braden), Chile, (Abst), Econ, Geol,, v, 66, pp. 977. Azzaria, L.M. 1963. A study of the distribution of traces of copper, lead and zinc i n the minerals of a Precambrian granite. Can. Mineralogist, v. 8, pp. 617-630. •  Baadsgaard, H., Folinsbee, R.E., and Lipson, J. I 9 6 I . Potassiumargon dates of biotites from Gordilleran granites. B u l l . Geol. Soc. Amer., v. 72, pp. 689-702. Bailey, G.B. and McCormick, G.R. 1974. Chemical halos as guides to lode deposits ore i n the Park City d i s t r i c t , Utah. Econ. Geol., v. 69, pp. 377-382. Barnes, H.L., and Czamanske, G.K. 1967. S o l u b i l i t i e s and transport of ore minerals. In Geochemistry of Hydrothermal Ore Deposits, ed. H.L. Barnes, pp. 334-381. Holt, Rinehart and Winston, New York. Bergey, W.R., Carr, J.M., and Reed, A.J. 1971. The Highmont coppermolybdenum deposits, Highland Valley, B r i t i s h Columbia. Can. Inst. Min. Metall. B u l l . , v. 64, pp. 68-76. Blanchflower, J.D. 1972. Isotopic dating of copper mineralization at Alwin and Valley Properties, Highland Valley, B.C. Unpublished B. Sc. Thesis, 83 p. Blaxland, A.B. 1971» Occurrence of Zn i n granitic b i o t i t e s . Mineralium Deposita, v. 6, pp. 313-320.  323  Bolter, E., and Al-Shaieb, Z. 1971* Trace-element anomalies i n igneous wall rocks of hydrothermal veins. Geochemical Exploration, CIM Spec. Vol. 11, pp. 289-290. Boyle, R.W. 1961. The geology, geochemistry and origin, of the gold deposits of the Yellowknife d i s t r i c t . Geol. Surv, Can. Mem. 310. Boyle, R.W. 1965. Geology, geochemistry and origin of the leadz i n c - s i l v e r deposits of the Keno Hill-Galena H i l l area, Yukon Territory, Geol. Surv. Can. B u l l . 111. Boyle, R.W. 1967. Geochemical prospecting-retrospect and prospect. Geol. Surv. Can. Paper 66-54, pp. 30-43. Boyle, R.W., 1968. A source of metals and gangue elements i n epigenetic deposits. Mineralium Deposita, v. 3, pp. 174-177. Boyle, R.W. 1971. Boron and boron minerals as indicators of mineral deposits. (Abst.), Geochemical Exploration, CIM Spec. Vol. 11, pp. 12. Boyle, R.W., and Garrett, R.G. 1970. Geochemical prospecting - A review of i t s status and future. Earth Sci. Rev., v. 6, pp. 51-  75.  Brabec, D. 1970. A geochemical study of the Guichon Creek batholith, B r i t i s h Columbia. Unpublished Ph.D thesis, Univ. B r i t i s h Columbia, 146 p. Brabec, D. 1971. Aqua regia extractable vs. t o t a l copper and zinc content of granitic rocks. Soc, Min. Eng. Trans., v. 250,  pp. 94-97.  Brabec, D., and White, W.H. 1971. Distribution of copper and zinc i n rocks of the Guichon Creek batholith. Geochemical Exploration, CIM Spec. Vol. 11, pp. 291-297. Bradshaw, P.M.D. 1967. Distribution of selected elements i n feldspar, b i o t i t e and muscovite from B r i t i s h granites i n relation to mineralization. Inst. Mn. Metall. Trans., v. 76, pp. B137-148. Bradshaw, P.M.D., and Stoyel, A.J. 1968. Exploration f o r blind orebodies i n southwest England by the use of geochemistry and f l u i d inclusions. Inst. Min. Metall. Trans., v. 77, pp. B144152. Bradshaw, P.M.D., Clews, D.R., and Walker, J.L. 1970. Exploration Geochemistry, Part 4: Primary dispersion. Mining i n Canada, June, pp. 24-31.  324  B r i s t o l , G.C. 1968. The quantitative determination of minerals i n some metamorphosed volcanic rocks by x-ray powder d i f f r a c t i o n . Can. J . Earth S c i . , v. 5, pp. 235-242. B r i s t o l , C.C. 1972. Quantitative determination of some carbonate minerals i n greenschist facies meta-volcanic rocks. Can. J . Earth S c i . , v. 9, PP. 36-42. /  Brown, A.S. 1967. Investigation of mercury dispersion halos around mineral deposits i n central B r i t i s h Columbia. Geol. Surv, Can. Paper 66-54, pp. 73-83. Burnham, C.W. 1967. Hydrothermal f l u i d s at the magmatic stage. In Geochemistry of Hydrothermal Deposits, ed. L.H. Barnes,  PP. 34-76.  Burns, R.G., and Fyfe, W.S. 1967. Crystal f i e l d theory and the geochemistry of transition elements. _In Researches i n Geochemi s t r y , ed, A.H. Abelson, v, 2, pp, 259-285. Wiley and Sons, New York. Cameron, E.M. 1972. Three geochemical standards of sulphidebearing ultramafic rocks: UM.l, UM.2, UM.4. Geol. Surv. Can. Paper 71-35, 10 p. Carr, J.M. 1962. The geology of part of Thompson River Valley between Ashcroft and Spences Bridge. B r i t . Columbia Dept. Mines Pet. Res. Annual Rept., pp. 28-45. Carr, J.M. 1966. Geology of the Bethlehem and Craigmont copper deposits. In Tectonic History and Mineral Deposits of the Western Cordillera, CIM, Spec. Vol. 8, pp. 321-328. Carr, J.M. 1967, Lornex. B r i t . Columbia Dept. Mines Pet. Res. Annual Rept., pp. 157-158. Carson, D.J.T., and Jambor, J.L. 1974. Mineralogy, zonal relationships and economic significance of hydrothermal alteration at porphyry copper deposits, Babine Lake area, B r i t i s h Columbia. Can. Inst. Min. Metall. B u l l . , v. 67, PP. 110-133. Chrismas, L., Baadsgaard, H., Folinsbee, R.E., F r i t z , P., Krouse, H.R., and Sasaki, A. 1969. Rb/Sr, S, and 0 isotopic analyses indicating source and date of contact metasomatic copper deposits, Craigmont, B r i t i s h Columbia, Canada. Econ. Geol., v, 64, pp. 479-488. Coope, J.A. 1973. Geochemical prospecting f o r porphyry copper-type mineralization - a review. J . Geochem. Explor., v. 2, pp. 81-  102.  325 Cornwall, H.R., and Rose, H.J. 1957. Minor elements i n Keeweenawan lavas, Michigan. Geochem. et Cosmochim. Acta, v. 12, pp. 209224. CuTbert, R.R.,1972. Abnormalities i n the distribution of K, Rb and Sr i n the Coast Mountains batholith, B r i t i s h Columbia. Geochim. et Cosmochim. Acta, V. 36, pp. 1081-1100. Curtis, CD. 1964. Applications of the c r y s t a l - f i e l d theory to the inclusion of trace transition elements i n minerals during magmatic differentiation. Geochim. et Cosmochim. Acta, v. 28,  pp. 389-403.  Cuttita, F., Senftle, F i ^ . , and Walker, E.C. i960. Preliminary tests on isotopic fractionation of copper absorbed on quartz and sphalerite. U.S. Geol. Surv. Prof. Paper 400B, pp. 44-53. Banner, W.R., and Nestell, M.K. 1971. Permian-Triassic of the Western Cordilleran eugeosyncline. (Abst), B u l l . Can. Pet. Geol., v. 19, pp. 324-325. Darling, R. 1971. Preliminary study of the distribution of minor and trace elements i n biotite from quartz monzonite associated with contact-metasomatic tungsten-molybdenum-copper ore, C a l i f ornia, U.S.A. Geochemical Exploration, CIM Spec. Vol. 11, pp. 315-322. Dass, A.S., Boyle, R.W., and Tupper, W.M. 1973. Endogenic halos of the native s i l v e r deposits, Cobalt, Ontario Canada. Geochemical Exploration 1972, pp. 25-35. Inst. Min. Metall. London. Davis, J.D., and Guilbert, J.M. 1973. Distribution of the radioelements potassium, uranium and thorium i n selected porphyry copper deposits. Econ. Geol., v. 68, pp. 145-160. De Grys, A. 1970. Copper and zinc i n a l l u v i a l magnetites from central Ecuador. Econ. Geol., v. 65, pp. 714-717. Dercourt, J. 1972. The Canadian Cordillera, the Hellenides, and the sea-floor spreading theory. Can. J. Earth S c i . , v. 9, PP. 709-  743.  Dirom, G.E. 1965. K-Ar age determination i n biotites and amphiboles, Bethlehem Copper property, B.C. Unpublished M.A.Sc. thesis, Univ. B r i t i s h Columbia. Dolezal, J . , Povondra, P., and Sulcek, Z. 1966. Decomposition techniques i n inorganic analysis, I l i f f e Books Ltd. London, 224 p.  326  Doyle, P.J. 1972. Regional stream sediment reconnaissance and trace element content of rock, s o i l and plant material i n eastern Yukon Territory. Unpublished M.Sc. thesis, Univ. B r i t i s h Columbia, 132 p. Faure, G., and Hurley, P.M. 1963. The isotopic compositions o f strontium i n oceanic and continental basalts; Application to the origin of igneous rocks. J. Petrol., v. 4, pp. 31-50, F i e l d , C.W., Jones, M.B.,.and Bruce, W.R. 1973. Porphyry coppermolybdenum deposits i n the P a c i f i c Northwest. A.I.M.E. Preprint 73-S-69. Fipkie, C.E. 1972. Some aspects of the hydrothermal mineralogy of the Lornex porphyry copper deposit, Highland Valley, B.C. Unpublished B.Sc. thesis, Univ. B r i t i s h Columbia, 99 p. Flanagan, F.J. 1973• 1972 values f o r international geochemical reference samples. Geochim. Cosmochim. Acta., v. 37, PP» 1189-  1200.  Folinsbee, R.E., Baadsgaard, H., and Lipson, J. I960. Potassiumargon time scale, Rept. XXI, i n t . Geol. Cong., Norden, Pt. I l l , pp. 7-17. Foster, J.R. 1973* The efficiency of various digestion procedures i n the extraction of metals from rocks and rock-forming minerals Can. Inst. Min. Metall. B u l l . , v. 66, pp. 85-92. Fountain, R.J. 1972. Geological relationships i n the Panguna porphyry copper deposit, Bougainville Island, New Guinea. Econ. Geol., v. 67, pp. 1049-1064. Fournier, R.O. 1967. The porphyry copper deposit exposed i n the Liberty open-pit mine near Ely, Nevada. Econ. Geol., v, 62, pp. 57-81. Friedrich, G.H. 1971. Use of mercury i n geochemical exploration. Geol. Mijnbouw, v. 50, pp. 768-770. Garrett, R.G. 1969. The determination of sampling and analytical errors i n exploration geochemistry. Econ. Geol., v. 64, pp. 568-569; discussion, v. 68, pp. 281-283 (1973). Garrett, R..G. 1971. Molybdenum, tungsten and uranium i n acid plutonic rocks as a guide to regional exploration, S.E. Yukon, Can. Min. Journ., A p r i l , pp. 37^40 Goldschimdt, V.M. 195^« Geochemistry.  Oxford University Press.  327  Goodfellow, W.D. 1974. Major and minor element halos i n volcanic rocks at Brunswick No. 12 sulphide deposit, N.B. Canada. (Abst.) Proc. 5th Intern. Geochem. Explor. Symp., A p r i l 1974, Vancouver, pp, 3*<~35. Gott, G.B., and McCarthy, J r . , A.H. 1966, Distribution of gold, s i l v e r , tellurium and mercury i n the Ely mining d i s t r i c t , White Pine:. County, Nevada. U.S. Geol. Surv. Circ. 535» 5 P» Graybeal, F.T. 1973. Copper, manganese, and zinc i n coexisting mafic minerals from Laramide intrusive rocks i n Arizona. Econ. Geol., V. 68, pp. 785-798. Gresens, R.L. I967. Composition-volume relationships of metasomatism. Chem. Geol., v.2, pp. 47-65. Guilbert, J.M., and Lowell, J.D. 1973. Potassic alteration i n porphyry copper deposits. (Abst.), Econ. Geol., v. 68, pp.  703.  Gunton, J.E., and Nichol, I. 1974, Chemical zoning associated with the Ingerbelle-Copper Mountain mineralization, Princeton, B r i t i s h Columbia. (Abst.), Proc. 5th Intern. Geochem. Explor. Symp., A p r i l , Vancouver, pp. 38-39. Haack, U. 1969. Spurenelemente i n biotiten aus graniten and gneisen. Contrib. Mn. Pet., v. 22, pp. 83-I26. Hamil, B.M., and Nackowski, M.P. 1971. Trace-element distribution i n accessory magnetite from quartz monzonite intrusives and i n relation t o sulfide mineralization i n the Basin and Range Province of Utah and Nevada - a preliminary report. Geochemical Exploration. CIM Spec. Vol. 11, pp. 331-333. Hatherton, T., and Dickinson, W.R. 1969. The relationship between andesitic volcanism and selsmicity i n Indonesia, the Lesser A n t i l l e s and other island arcs. J . Geophys. Res., v. 74,  pp. 5301-5310.  Hausen, D.M. and'Eerr, P.F. 1971. X-ray d i f f r a c t i o n methods i n evaluating potassium s i l i c a t e alteration i n porphyry mineralization. Geochemical Exploration. CIM Spec. Vol. 11, pp. 334340.  Hawkes, H.E., and Webb, J.S. 1962. Geochemistry i n Mineral Exploration, Harper and Row, 415 p. Haynes, S.J., and Clark, A.H. 1972. A rapid method f o r the determination of chlorine i n s i l i c a t e rocks using ion-selective electrodes. Econ. Geol., v. 67, pp. 378-382.  328  Hedge, G.E. 1966. Variations in radiogenic strontium found in volcanic rocks. J. Geophys. Res., v. 71, PP. 6119-6126. Heier, K.S., and Adams, J.A.S. 1964. The geochemistry of the alkali metals. Phys. Chem. Earth, v. 5, pp. 253-381. Helgeson, H.G. 1970. A chemical and thermodynamic model of ore deposition in hydrothermal systems. Mineral. Soc. Amer. Spec. Paper 3, pp. 155-186. Hemley, J.J., and Jones, W.R. 1964. Chemical aspects of hydrothermal alteration with emphasis on hydrogen metasomatism. Econ. Geol.,  v. 59, PP. 538-569.  Hewett, F.G. 1972. Mineral deposits of the Highland Valley. Unpublished report, Geol. 409 course, Univ. British Columbia, 45 P. Hoffman, S.J. 1972. Geochemical dispersion in bedrock and glacial overburden around a copper property in south-central B.C. Unpublished M.Sc. thesis, Univ. British Columbia, 209 p. Holland, H.D. 1972. Granites, solutions and base metal deposits. Econ. Geol. v. 67, pp. 281-301. Huff, L.C. 1971. A comparison of alluvial exploration techniques for porphyry copper deposits. Geochemical Exploration. CIM Spec. Vol. 11, pp. 190-194. Hurley, P.M. 1968. Absolute abundances and distribution of Rb, K and Sr in the earth. Geochim. Cosmochim Acta, v, 32, pp. 273-  283.  Ineson, P.A. 1969. Trace-element aureoles in limestone wall rocks adjacent to lead-zinc-barite-fluorite mineralization in the northern Pennine and Derbyshire ore-fields. Inst. Min. Metall. Trans., v. 78, pp. B29-B40. Ineson, P.A. 1970. Trace-element aureoles in limestone wall rocks adjacent to fissure veins in the Eyam area of the Derbyshire ore-field. Inst. Min. Metall. Trans., v. 79, PP. B238-B245. Jakes, P., and White, A.J.R. 1970. K/Rb ratios of rocks from island arcs. Geochim. Cosmochim. Acta, v. 3^» PP. 849-856. Jonasson, I.R., Lynch, J.J. and Trip, L.J. 1973* Field and laboratory methods used by the Geological Survey of Canada in geochemical surveys, 12. Mercury in ores, rocks, soils, sediments and water. Geol. Surv. Can. Paper 73-21, 22 Po.  329  Jones, M.B., Allen, J.M., and F i e l d , C.W. 1972. Hydrothermal alteration and mineralization, Valley Copper deposit, B r i t i s h Columbia. (Abst.), Econ. Geol., v. 67, pp. 1006. Kesler, S.E., Van Loon, J.C., and Moore, CM. 1973. Evaluation of ore potential of granodioritic rocks using water extractable chloride and fluoride. Can. Inst. Min. Metall. B u l l . , v. 66, pp.  56-6O.  Kesler, S.E., Van Loon, J.C. and Bateson, J.H. 1973* Analysis of fluoride i n rocks and an application to exploration, J . Geochem. Explor., v. 2 , pp. 11-17. K i s t l e r , R.W., Evernden, J.F., and Shaw, H.R. 1971. Sierra Nevada plutonic cycle: Part 1, Origin of composite granitic batholiths. Geol. Soc. Amer. B u l l . , v. 82, pp. 853-868. Korzhinskii, D.S. 1968. The theory of metasomatic zoning, Mineralium Deposita, v, 3 , pp. 222-231. Krauskopf, K.B. I 9 6 7 . Source rock f o r metal-bearing f l u i d s . In Geochemistry of Hydrothermal Ore Deposits, ed. H.L. Barnes, pp. 1-33» Holt, Rinehart and Winston, New York. Kuroda, P.K., and Sandell, E.B. 1953. Geol, Soc. Amer. B u l l . , v. 64, pp.  Chlorine i n igneous rocks, 879-896.  Larsen, E.S.J., and Poldervaart, A. I96I. Petrologic study of Bald Rock batholith, near Badwell Bar, California. Geol. Soc. Amer. B u l l . , v. 7 2 , pp. 6 9 - 9 2 . Leech, G.B., Lowdon, J.A., Stockwell, C.H., and Wanless, R.K. I963. Age determinations and geological studies. Geol. Surv. Can. Paper 63-I7. Levinson, A.A. 1974. Introduction to Exploration Geochemistry. Applied Publishing Ltd., Calgary. Lovering, T.G., Cooper, J.R., Drewes, H., and Cone, G.C 1 9 7 C Copper i n b i o t i t e from igneous rocks i n southern Arizona as an ore indicator. U.S. Geol. Surv. Prof. Paper 700-B, pp. B l - 8 . Lowell, J.D., and Guilbert, J.M. 1970. Lateral and v e r t i c a l a l t e r ation-mineralization zoning i n porphyry ore deposits. Econ. Geol., v. 64, pp. 373-4O8. Luth, W.C, Jahns, R.H., and Tuttle, D.F. 1964. The granitic system af pressures of 4 - lOkb. J . Geophys. Res., v. 6 9 , pp. 759-773*  330  Lyakhovich, V.V. 1959* Some data on composition of accessory magnetites: I.G.E.M. Academy of Science U.S.S.R., v. 3, pp. 89-103 ( i n Russian). Lynch, J.J. 1971. The determination of copper, nickel and cobalt i n rocks by atomic absorption spectrometry using a cold leach. Geochemical Exploration. CIM Spec. Vol. 11, pp. 313-314. McCarthy, J.H. 1972. Mercury vapor and other v o l a t i l e components i n the a i r as guides to ore deposits. J. Geochem. Explor., v. 1, pp. 143-162. McDougall, I., and Lovering, J.F., 1963. Fractionation of Cr, Ni, Co and Cu i n differentiated dolerite-lamprophyre sequence at Red H i l l , Tasmania. Geol. Soc. Aust. Jour., v. 10, pp. 325-  338.  McMillan, W.J. 1971. Valley Copper. In Geology, Exploration and Mining i n B r i t i s h Columbia, 1970, BCDM Rpt., pp. 35^-369. McMillan, W.J. 1972. The Highland Valley porphyry copper d i s t r i c t . Guidebook, No. 9» Intern. Geol. Cong,, pp. 53-69. McMillan, W.J. 1973. Geological Map of the Highland Valley. BCDM Rept., ( i n press). McNerney, J.J., and Buseck, P.R. 1973. Geochemical exploration using mercury vapor. Econ. Geol., v. 68, pp. 1313-1320. Meyer, C., and Hemley, J.J. 1967. Wall-rock alteration. In Geochemistry of Hydrothermal Ore Deposits, ed, H.L. Barnes, pp. 166-236, Holt, Rinehart and Winston, New York. Mitchell, A.H.G., and Garson, M.S. 1972. Relationship of porphyry copper and circum-Pacific t i n deposits to palaeo-Benioff zones, Inst. Min, Metall. Trans., v. 81, pp. B10-B25. Monger, J.W., Souther, J.G., and Gabrielse, H. 1972. Evolution of the Canadian Cordillera: A plate tectonic model. Am. Jour. S c i .  v. 272, pp. 577-602.  Nairis, B. 1971. Endogene dispersion aureoles around the Rudtjebacken sulphide ore i n the Adak area, northern Sweden. Geochemi c a l Exploration. CIM Spec. Vol. 11, pp. 357-374. Nielsen, R.L. 1968. Hypogene texture and mineral zoning i n a copperbearing granodiorite porphyry stock, Santa Rita, New Mexico. Econ. Geol., v. 63, pp. 37-50. Noble, J.A. 1970. Metal provinces of the western United States. Geol. Soc. Amer. B u l l . , v. 81, pp. 1607-1624,  331  Nockolds, S.R., and Allen, R. 1953' The geochemistry of some igneous rock series. Geochim. Cosmochim. Acta, v. 4, pp. 105-142. Norrish, K., and Hutton, J. 1969. An accurate X-ray spectrographic method f o r the analysis of a wide range of geological samples. Geochim. Cosmochim. Acta,, v.- 33» PP. 431-453. Northcote, K.E. 1968. Geology and geochemistry of the Guichon Creek batholith. Unpublished Ph.D thesis, Univ. B r i t i s h Columbia, 186 p. Northcote, K.E. 1969. Geology and geochronology of the Guichon Creek batholith. B r i t i s h Columbia Dept. Mines Pet. Res., Rept.,  56, 73P.  Olade, M., and Fletcher, K. 1974. Potassium chlorate-hydrochloric acid; A sulphide-selective leach f o r bedrock geochemistry. J. Geochem. Expl., v. 3, ( i n press). Olade, M.A. and Fletcher, W.K. 1974. Primary dispersion of rubidium and strontium around porphyry copper deposits, Highland Valley, B.C. Econ. Geol., ( i n press). Olade, M., Fletcher, K., and H.V. Warren. 1974. Barium-strontium relationships at Highland Valley porphyry copper deposits, B.C. Western Miner ( i n press). Orion Research 1970. Manual on specific ion meters. Orion Research, 26 p. Oyarzun, J.M. 1974. Rubidium and strontium as a guide to copper mineralization emplaced i n some Chilean andesitic rocks. (Abst.), Proc. 5th Intern. Geochem. Explor. Symp., A p r i l , Vancouver, pp. 48. Pantazis, Th.M., and Govett, G.J.S. 1973. Interpretation of a detailed rock geochemical survey around Mathiati mine, Cyprus. Jour. Geochem.. Explor., v. 2, pp. 25-36. Parry, W.T. 1972. Chlorine i n biotite from Basin and Range plutons. Econ, Geol., v. 67, pp. 972-975. Parry, W.T., and Nackowski, M.P. 1963. Copper, lead and zinc i n biotites from Basin and Range quartz monzonites. Econ. Geol., v. 58, pp. 1126-1144. Peto, P. 1973. Petrochemical study of the Similkameen batholith, B r i t i s h Columbia. Geol. Soc. Amer. B u l l . , v. 84, pp. 3977-3984. Peto, P. 1974. Plutonic evolution of the Canadian Cordillera. Geol. Soc. Amer. B u l l . , v. 85, pp. 1269-1276.  332  P h i l i p s , W.J. 1973. Mechanical effects of retrograde b o i l i n g and i t s probable importance i n the formation of some porphyry copper deposits. Inst. Min. Metall. Trans., v. 82, pp. B90-B98. Putman, G.W. 1972. Base metal distribution i n granitic rocks: Data from the Rocky H i l l and Lights Creek stocks, California. Econ. Geol., v. 67, pp. 511-527. Putman, G.W. 1973• Biotite-sulfide equilibrium i n granitic rocks: a revision. Econ. Geol., v. 68, pp. 884-891. Putman, G.W., and Burnham, C.W. 1963. Trace elements i n igneous rocks, northwestern and central Arizona. Geochim. Gosmochim. Acta, v. 27, PP. 53-106. Rabinovich, A.V., and Badalov, S.I. 1968. Geochemistry of copper i n some intrusives of Karamazar and West Uzbekistan. Geochem. Intern, v. 8, pp. 146-150. Rabinovich, A.V., Muravera, A.N., and Zhdanova, M.V. 1958. Molybdenum content of certain rocks and minerals i n the intrusives of Eastern Transbaikal. Geochem, Intern,, v. 2, pp. 155-162. Ringwood, A.E. 1955« The principles governing trace element d i s tribution during magmatic c r y s t a l l i z a t i o n . Geochim. Cosmochim. Acta, v. :7, pp. 189-202; 242-254.  Rose, A.W. 1970. Zonal relations of wall rock alteration and sulfide distribution-at porphyry copper deposits. Econ. Geol,, v. 63, pp. 920-936.  Rouse, G.E., and Stevens, D.M, 1971, The use of sulfur dioxide gas geochemistry i n the detection of sulfide deposits. Paper presented at AIME Ann. Gen, Meeting, March 1971, Sakrison, H.C. 1971, Rock geochemistry - i t s current usefulness on the Canadian Shield. Can. Inst, Min, Metall, B u l l . , v. 64, pp. 28-31.  Schau, M. 1970. Discussion of paper by Chrismas et a l . , 1969. Econ, Geol., v. 65, pp. 62-63; reply to discussion, pp, 63-64. Sheppard, S.M.F., Nielsen, R.L:, and Taylor, J r . , H.P. 1969, Oxygen and hydrogen isotope ratios of clay minerals from porphyry copper deposits. Econ. Geol., v. 64, pp. 755-777/ Sheraton, J.W., and Black, L.P. 1973« Geochemistry of mineralized granitic rocks of northeast Queensland. Jour. Geochem, Explor., v. 2, pp. 331-348.  333  Shikawa, H., Kuroda, R., and Sudo, T. 1962. Minor elements i n some altered zones of Kuroko (black ore) deposits i n Japan. Econ. Geol., v. 57, pp. 785-789. Shikawa, H., Tono, N., and Wakasa, K. 1974. Geochemical exploration f o r the Kuroko deposits i n the northeast Honshu, Japan. (Abst.), Proc. 5th Int. Geochem. Explor. Symp., A p r i l , Vancouver, pp. 55-56. S i l l i t o e , R.H. 1972. A plate tectonic model f o r the origin of porphyry copper deposits. Econ. Geol., v. 67, pp. 184-197, S i n c l a i r , A.'J, 1974. Selection of threshold values i n geochemical data using probability plots. Jour. Geochem. Explor., v. 3, pp. 129-149. Smith, T.E. 1974. The geochemistry of the granitic rocks of Halifax County, Nova Scotia. Can. J. Earth S c i . , v, 11, pp.  650-656.  Stanley, A. 1964. Relation of copper to rock types i n an area of known economic mineralization. Econ. Geol., v. 59. PP. 1492-  1496.  Stanton, R.E. 1966. Rapid Methods of Trace Analysis f o r Geochemical Application. E. Arnold, London, 96 p. Taubeneck, W.H. 1965. An appraisal of some potassium-rubidium ratios i n igneous rocks. Jour. Geophys. Res., v. 70, pp. 475-  478.  Taubeneck, W.H. 1967. Petrology of Cornucopia Tonalite Unit, Cornucopia stock, Wallowa Mountains, northeastern Oregon. Geol. Soc. Amer. Spec. Paper 91» 56 p. Tauson, L.V., Sheremet, Y.M., and Antipin, V.S. 1970. Trends i n the distribution of molybdenum i n Mesozoic granitoids of northeastern Transbakykalia. Geochem. Intern., v. 8, pp. 637-642. Theobald, Jr., P.K., Overstreet, W.C., and Thompson, CE. 1962. Minor elements i n a l l u v i a l magnetite from the Inner Piedmont Belt, North and South Carolina. U.S. Geol. Surv. Prof. Paper 554-A, 34p. Theodore, T.G., and Nash, J.T. 1973. Geochemical and f l u i d zonation at Copper Canyon, Lander County, Nevada. Econ. Geol., v. 68,  PP. 565-570.  Thurlow, J.G. 1974. Lithogeochemistry of the Buchans massive sulphide deposits. (Abst.), Paper presented at CIM Ann. Gen. Mtg, A p r i l 1974, Montreal.  334 Tooker, E.W. 1963. Altered wall rocks i n the central part of the f a u l t Range Mineral Belt, Gulpin and Clear Creek counties, Colorado. U.S. Geol. Surv. Prof. Paper 439, 102p. Turekian, K.L. and Kulp, J.L. 1956. The geochemistry of strontium. Geochim. Cosmochim. Acta, v. 10, pp. 245-296. Turekian, K.L., and Wedepohl, K.H. 1961. Distribution of the elements i n some maj'or units of the Earth's crust. Geol. Soc. Amer. B u l l . , v. 72, pp. 641-664. 1  Tuttle, O.F., and Bowen, N.L. 1958. Origin of granite i n the l i g h t of experimental studies i n the system NaAlSi~0g-KAl-Sio0o-Si0 H 0. Geol. Soc. Amer. Mem. 74. 2  2  Van Loon, J . C , Kesler, S.E., and Moore, CM. 1973. Analysis of water-extractable chloride i n rocks by use of a selective ion electrode. Geochemical Exploration 1972, pp. 429-434. IMM, London. Wager, L.R., and Mitchell, R.L. 1951. The distribution of trace elements during strong fractionation of basic magma - a further study of the Skaergaard intrusion, East Greenland. Geochim. Cosmochim. Acta, v. 1, pp. 129-208. Wager, L.R., and Brown, G.M. 1967. Layered Igneous Rocks. and Boyd, Edinburgh and London, 588 p.  Oliver  Warren, H.V., and Delavault, R.E. i960. Readily extractable copper i n eruptive rocks as a guide f o r prospecting. Econ. Geol.,  v. 54, pp. 1291-1297.  Warren, H.V., Church, B.N., and Northcote, K.G. 1974. Barium-strontium relationships; possible geochemical tool i n search f o r orebodies, Western Miner, A p r i l , pp. 107-111. Westermann, C J . 1970. A petrogenetic study of the Guichon Creek batholith, B.C. Unpublished M.Sc, thesis, Univ. B r i t i s h Columbia, 116 p. White, W.H., Thompson, R.M., and McTaggarK, K.C 1957. The'geology and mineral deposits of Highland Valley, B.C. Can. Inst. Min. Metall. Trans., v. 60, pp. 273-289. White, D.E. I968. Environment of generation of some base metal deposits. Econ. Geol. v. 63, p. 301-335. Wright, J.B., and McClurry, P. 1973. Magmas, mineralization and seagloor spreading. Geol. Rundsch., v. 62, pp. 116-125.  335  Zlobin, B.I., et a l . 1967. Copper i n intrusions of the central part of northern Tian-Shan as related to the problems of metallogeny. Geologya Rudnyh Mestorozdhenii, No. 1, pp. 4556 ( i n Russian).  336  APPENDICES  337  APPENDIX A Bethlehem-JA (Sample locations and A n a l y t i c a l Results)  ^5  0  244m  (Geology, after  FIGURE 77:  Location of samples, Bethlehem-JA Suboutcrop l e v e l .  Bethlehem Mining Staff)  339  BETHLEHEM-JA ATOMIC SAMP.  SUBOUTCROP  LEVEL  ABSORPTION ANALYSIS (VALUES IN PPM)  t LOC.COORD  CU  (HN03-HCLC4  DIGESTION) " 1  ZN  1  U  J  BN  NI  1692.837 1775.473 6535.980 6220.469 19547.449 5117.715 1166.666 328.860 6 7 2 5 . 1 17 3973.669 5311.582 103.444 118.827 2754.736 3510.393 700.666 361.314 4953.898 605.170 1077.945 5036.199 1419.913 2403.555 1128.453 3210.041 2762.178 664.644 1280.636 1527.321 8908.797 326.573 1947.921 135.017 4013.349 8 7 7 . 136 732.641 191.453 723.205 1795.757 2988.712 223.611 3851 . 3 4 9 213.480 205.794 4657.453 237.677 1580.017 493.235 2444.422 2733.765 613.838  15.914 14.713 22.217 61.356 19.620 11.450 56.146 . 12.060 28 951 t ' 4 557 11 « 8«3\ 11.8 19.086 13.202 23.316 5.103 12.586 23.316 23.117 12.301 14.596 33.305 25.278 11.216 9.996 10.977 36.836 31.923 16.479 16.508 16.143 12.017 18.414 15.285 18.377 48.547 49.668 21.971 17.557 14.370 17.931 15.644 19.680 19.286 22.459 28.608 19.313 46.022 35.302 21.815 15.757  2 0 v l l l 130.648 140.775 123.633 126.070 39.525 101.003 189.032 169.087 8 5 . 228 136.469 213.640 224.554 129.731 68.462 77.26 1 347.539 249.638 94.433 105.800 103.098 103.098 120.747 134.628 111.820 338.685 283.006 147.257 129.120 124.546 153.149 1 2 2 . 417 185.846 190.626 224.882 236.709 173.265 252.838 269.409 201.566 56.919  0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 CO 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 CO CO 0.0 0.0 0.0 0.0 0.0  ?•? 0.0 4.236 0.0 2.926 0.0 0.0 5.221 3.777 CO 6.045 8.262 5.781 CO 3.253 0.0 12.878 7.698 CO CO 0.0 0.0 0.0 4.893 9.693 7.698 5.485 9.860 0.0 0.0 0.0 CO 6.045 5.221 CO CO 0.0 0.0 0.0 0.0 0.0  270 272 275 277 279 281 283  359.223 1 7 5 . 158 1125.930 1059.831 69.01 1 224.076 2086.849  28.406 15.688 16.056 16.787 22.381 26.152 33.876  232.058 143.645 124.503 98.787 172. 363 171.160 212.065  0.0 CO 0.0 0.0 0.0 0.0 0.0  CO 0.0 CO 0.0 CO 0.0 CO  250 550 375 525 75 75 225  ^t'tfa  N  0.0 0. 0 1.092 0.0 5.567 .0.0 0.0 n n  PB  119 200 600 152 5 5 0 4 5 0 155 600 500 157 650 4 5 0 160 600 400 162 450 4 5 0 164 7 5 0 450 166 500 5 0 0 169 700 400 172 500 4 0 0 174 550 350 176 i / D 650 D 3 U 350 «o 178 700 500 181 400 5 0 0 183 450 350 184 4 0 0 4 0 0 186 350 450 188 700 3 0 0 190 800 300 193 800 4 0 0 196 750 350 199 7 5 0 2 5 0 201 650 250 203 5 5 0 5 5 0 206 450 550 209 3 5 0 5 5 0 2 1 2 700 200 214 800 2 0 0 216 550 650 2 1 7 400 6 0 0 220 300 600 223 300 500 226 600 6 0 0 229 650 550 2 3 2 750 5 5 0 234 850 3 5 0 237 850 250 2 4 0 350 6 5 0 2 4 3 250 650 245 250 550 248 500 300 250 600 300 252 850 450 253 800 500 256 500 600 259 250 450 261 900 200 263 850 150 2 6 5 750 150 267 200 500 269 450 650 950 150 50 050 965 650 350  131.765 10 1. 506 196.577 254.251 357.867 99.178 476.038 1 14.8R? 2 0 s ' ^  AG  0.0 CO 4.295 19.172 0.0 0.0 12.911 -> " « • * 3  n  n  °*°  2  1  5  0.0 0.0 0.0 0.0 0.0 0.0 0.0 - °'° 0.0  ° '° n  n  ° ' ° 00..00 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 CO CO 0.0 0.0 0.0 0.0 0.0 0.0 0.0 C O 0. 0.0  340 BETHLEHEM-JA SPECTROGRAPHS  SUBOUTCBOP  ANALYSIS (VALUES  SAMP,  149 152 155 157 160 162 164 166 169 172 174 176 178 181 183 184 186 188 190 193 196 199 201 203 206 209 212 214 216 217 220 223 226 229 232 234 237 240 243 245 248 250 252 253 256 259 261 263 265 267 269 270 272 275 277 279 281 283  LEVEL  B  IS  SR  0 700 20 500 15 700 15 500 30 100 60 400 20 500 0 700 10 800 0 300 60 100 20 400 15 800 10 800 0 500 0 200 0 700 0 600 0 600 10 500 01000 10 800 20 800 101000 10 600 01000 201000 101000 01000 0 700 01000 10 800 30 800 30 600 101000 20 700 10 700 10 800 0 700 0 700 10 700 10 400 10 900 15 700 15 600 0 600 15 800 01000 0 800 20 400 10 800 10 800 20 600 0 600 0 600 101000 0 500 0 800  PPM) TI  600 1500 1000 2001 500 2000 2001 700 2001 700 1000 500 1000 800 1000 500 500 700 1000 1000 2000 1000 800 2000 1000 1000 2001 1500 700 1000 1000 800 1000 2000 1500 1500 1000 2001 1000 1000 600 2001 2000 1000 2000 1000 1500 2001 2000 1000 2001 2001 1000 1500 700 2000 2000 900  IN  V  50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50  30 40 50 80 30 50 80 30 100 30 20 15 50 30 30 10 20 40 40 30 50 50 40 30 20 30 70 60 30 30 40 38 50  50  50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50  50 50 50 50 40 40 50 30 40 60 30 60 30 70 80 50 40 60 60 40 50 30 60 50 30  MO  0 4 0 30  BA BIGA  SH  600 020 0 500 020 0 400 020 0 300 020 0 1500 020 0 150 500 020 0 100 200 020 0 0 500 020 0 10 600 020 0 0 500 020 0 400 400 020 0 10 500 020 0 0 500 020 0 10 400 020 0 0 600 020 0 40 300 020 0 0 500 020 0 020 0 500 020 0 500 0 500 020 0 20 500 020 0 20 500 020 0 0 50 500 020 10 300 020 0 0 500 020 0 15 600 020 0 15 500 020 0 01000 020 0 0 600 020 0 0 600 020 0 0 700 020 0 020 0 5 600 020 0 0 500 15 400 020 0 0 600 020 0 0 500 020 0 0 600 020 0 8 400 020 0 0 500 020 0 15 400 020 0 0 300 020 0 15 500 020 0 0 500 020 0 0 500 020 0 020 0 101500 10 400 020 0 0 500 020 0 0 500 020 0 0 400 020 0 0 400 020 0 0 400 020 0 0 400 020 0 0 500 020 0 15 500 020 0 0 0 600 020 0 500 020 0 0 400 020 0 0 400 020 10  in i  0  800ft  [rrTT-"--^!^""""" "  0  FIGURE 78:  —  " |  244m  Location of samples, Bethlehem-JA  (Geology, after  2800 l e v e l .  Bethlehem Mining  Staff)  342  BETHLEHEM-JA  2800 LEVEL  ATOMIC ABSORPTION ANALYSIS (VALUES IN PPM)  . #  LOC.COORD  150 200 600 153 550 450 156 600 500 158 650 450 160 6 00 400 162 450 450 165 750 450 167 500 500 170 700 400 172 500 400 174 550 350 176 650 350 179 700 500 181 400 500 184 400 400 186 350 450 188 700 300 191 800 300 194 800 400 197 750 350 199 750 250 201 650 250 204 550 550 207 450 550210 350 550 212 700 200 214 800 200 218 400 600 221 300 600 224 300 500 227 600 600 230 650 550 233 750 550 235 850 350 238 850 250 241 350 650 244 250 650 246 250 550 248 500 300 250 600 300 254 800 500 257 500 600 259 250 450 261 900 200 263 850 150 266 750 150 267 200 500 271 950 250 273 150 550 2 75 50 375 277 050 525 279 965 75 281 650 75 283 350 225  (HN03- HCL04 DIGESTION)  CU  ZN  985.699 3339.367 3313.963 4460.469 19547.449 5117.715 890.089 899.189 2056.387 3973.669 5311.582 103.444 566.357 2754.736 700.666 361.314 4953.898 936.281 231.847 9212.871 1419.913 2403.555 129.453 674.802 2038.765 664.644 1280.636 3144.409 2096.329 6248.395 252.816 356.683 23.622 1583.558 2670.732 1914.531 :563.530 2096.329 223.611 3851.349 397.143 1738.952 237.677 1580.017 493.235 573.549 2733.765 645.205 309.216 1125.930 1059.831  13.329 14.642 13.023 19.526 19.620 11.450 27.557 8.601 36.377 6.517 4.557 11.883 18.218 13.202 5.103 12.586 23.316 22.508 20.156 14.104 33.305 25.278 14.497 9.840 12.058 36.836 31.923 19.812 15.378 13.312 22.280 20.580 18.490 28.416 31.670 16.699 17.766 16.890 17.931 15.644 33.225 19.703 28.608 19.313 46.022 27.937 21.815 25.695 18.107 16.056 16.787  94.863 108.180 65.304 129.051 357.867 99.178 188.107 77.717 275.696 54.929 2C0.474 130.648 92.498 123.633 39.525 101.003 189.032 220.309 161.565 107.302 213.64C 224.554 139.235 134.475 187.438 347.589 249.638 130.648 102.200 131.260 222.593 185.846 179.815 196.064 264.706 102.499 347.232 180.132 153.149 122.417 401.691 224.882 236.709 173.265 252.838 176.883 201.566 159.787 124.503 124.503 98.787  0.0 0.0 0.0 0.0 5. 567 0.0 0.0 0.0 0.0 0.0 4. 606 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0. 0 0.0 0.0 0.0 0.0 0.0 0.0  0.0 0.0 0.0 6.154 0.0 0.0 6.776 2.600 0.0 0.0 0.0 0.0 6.870 0.0 0.0 0.0 5.221 0.0 13.114 8.861 8.262 5.781 0.0 0.0 0.0 12.878 7.698 0.0 0.0 3.417 10.528 4.893 6.705 5.551 5.057 0.0 0.0 0.0 0.0 0.0 4.728 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0  69.011 224.076 2086.849  22.38i 26.152 33.876  172.363 171.160 212.065  0.0 0.0 0.0  0.0 0.0 0.0  MN  . AG  NI  PB 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0. 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0  343  BETHLEHEM-JA  2 8 0 0 LEVEL  ATOMIC ABSORPTION A N A L Y S I S (TOTAL D I G E S T I O N ) (VALUES I N WEIGHT %) SAMP. 150 153 156 1.58 160 162 165 167 170 172 174 176 179 181 184 186 188 191 194 197 199 201 204 207 210 212 214 218 221 224 227 230 233 235 238 241 244 246 248 250 254 257 259 261 263 266 267 271 273 275 277 2 79 281 283  CAO  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  MGO  FE203  NA20  K20  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  3.055 3.012 2.444 3.155 1.535 1.748 2.742 5.471 3.126 1.037 1.208 1.208 1.833 2.288 0.782 2.458 2.984 2.842 2.586 2.032 3.652 2.842 2.814 2.814 2.600 3.197 3.481 2.387 2.373 2.174 4.206 2.998 2.941 2.302 3.226 2.799 3.737 2.757 3.169 2.231 3.183 3.012 3.425 4.718 4.050 2.927 3 . 140 3.069 2.160 3.297 2.757  1.126 0.968 0.991 1.655 0.822 0.923 1.880 0.855 2.544 0.349 0 . 191 0.383 1.362 0 . 889 0.146 0.720 1.745 1.688 2.645 1. 576 2.004 1.413 1.114 0.889 0.923 2.285 2.420 0.687 1.013 1.002 2.330 1.610 1.745 1.936 2.026 1.283 1.216 1.385 1 .204 0.923 2.082 1.227 1.193 1.947 2 . 701 1.891 1 .249 1. 981 1.249 0.878 1.272  3.310 2.207 6.517 3.441 3.931 2.276 4.497 2.276 4.966 1.828 0.897 1.517 4.000 1.979 0.862 2.186 3.524 3.448 2.621 2.600 4.345 3.662 2.931 2.600 2.400 4.214 4.524 1.862 2.586 1.862 3.766 3.579 3 . 138 5.724 4.317 3.076 3.345 3 . 193 2.972 1.517 3.586 2.979 3.097 5.586 5.317 3.503 3.386 4.469 3.000 3.379 3.276  3.733 3.968 1.178 3 . 776 2.030 2.602 3.824 2 . 165 3 . 896 3.054 1. 130 4.089 2.718 6.494 3.276 6.975 4.040 4.089 6.494 3.757 4.040 3.343 6.013 4.618 3.535 5.532 6. 013 3.535 3.992 3 . 896 7.456 5.772 6.494 3.088 4.089 4 . 570 3 . 992 5.772 3 . 968 3.824 6.253 5.051 3.559 3.992 3.848 4.064 3.463 3.848 6.253 3.944 5.291  0 0 0  1.441 1.525 2.655 1.205 6.121 2.966 2.147 0.631 1.365 4.002 4.275 3.154 2.495 1.271 4.096 1.761 1.836 1.177 1.789 3.390 2.043 1.620 1.318 0.772 1.789 1.365 1.761 1.742 1.554 1.836 1.365 1.337 1.196 2.618 1.601 1.337 1.620 1.460 0.989 1.930 1.196 1.384 1.224 1.761 1 .987 1.365 2.213 1 .930 1.940 1.507 1 .742  3.766 3.694 2.757  1.936 2 . 184 1.092  4 . 6 76 4.828 3.241  6.494 3 . 752 4 . 089  1.290 1.516 1.723  344  BETHLEHEM-JA SPECTROGRAPHS SAMP. 150 153 156 158 160 162 165 167 170 172 174 176 179 181 184 186 188 191 194 197 199 • 201 204 207 210 212 214 218 221 224 227 230 233 235 238 241 244 246 248 250 254 257 259 261 263 266 267 271 273 275 277 279 281 283  2800  LEVEL  ANALYSIS (VALUES I N PPM)  #  B  SR  0 700 0 700 10 5 0 0 10 7 0 0 30 100 60 400 0 600 0 600 101200 0 300 60 100 . 20 400 20 500 10. 8 0 0 0 200 0 700 0 600 10 6 0 0 0 500 0 400 10 8 0 0 20 8 0 0 600 800 40 800 201000 101000 40 600 0 800 0 700 0 500 101000 . 2 0 500 15 7 0 0 151000 0 800 15 7 0 0 15 500 10 7 0 0 10 4 0 0 10 6 0 0 0 800 0 600 15 8 0 0 01000 0 800 20 400 0 600 20 600 0 600 0 600 ;  101000 0 500 0 800  TI 1500 1000 2001 1000 500 2000 1000 1000 2000 700 1000 500 1000 800 500 500 700 1500 1000 1500 1000 800 1000 1000 1500 2001 1500 1000 1000 1000 1000 2000 1500 1500 1500 2000 1000 1000 600 2001 1500 1500 1000 1500 2001 2000 1000 1500 500 1500 700 2000 2000 900  IN 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 . 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 . 50 50 50 50 50 50 50  V  MO  BA  50 0 500 50 15 5 0 0 60 50 500 50 6 400 30 1500 50 1 5 0 5 0 0 40 0 600 50 20 700 100 0 700 30 0 500 20 4 0 0 4 0 0 15 10 5 0 0 40 7 500 30 10 4 0 0 10 40 3 0 0 20 0 500 40 5 500 40 0 400 50 0 50050 30 500 50 20 500 40 50 500 30 0 600 30 0 500 40 20 500 70 15 5 0 0 60 01000 40 80 5 0 0 30 0 500 50 20 400 50 50 400 50 0 400 50 20 3 0 0 60 0 800 50 0 500 40 10 4 0 0 50 10 5 0 0 40 20 300 30 0 300 40 15 5 0 0 40 0 400 40 0 600 30 10 4 0 0 70 0 500 80 0 500 50 8 600 40 0 400 50 0 400 30 0 600 50 15 5 0 0 30 0 600  020 0 020 0 020 0 020 0 020 0 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 020 0 2 0 15 020 0 020 0  60 50 30  020 020  0 0 0  500 400 400  BETHLEHEM-JA (VALUES I N PPM SAMP. # 150 153 156 158 160 162 165 167 170 172 174 176 179 181 184 186 188 191 194 197 199 201 204 207 210 212 214 218 221. 224 227 230 233 235 238 241 244 246 24" 250 254 257 259 261 263 271 273 275 277 279 281 283  RB 40 47 70 38 141 90 58 28 40 84 85 76 70 37 91 58 53 39 55 86 45 74 34 27 61 42 55 57 43 56 56 37 45 66 43 37 32 43 33 48 39 36 32 51 45 56 56 37 48 37 47 44  2800 L E V E L EXCEPT FOR  HG  SR RB/SR S I 0 2 639 10863.44 688 6862.38 339 20658.77 658 5862.47 100 1 4 1 0 5 2 . 8 9 392 23062.33 620 9460.64 653 4361.04 762 5260.97 242 34768.34 115 . 7 3 9 7 3 . 8 8 372 20469.76 476 14763.42 751 4964.82 216 42164.62 829 7067.04 755 7063.13 860 4563.25 536 10357.60 662 13061.68 803 5660.21 576 12860.99 735 4664.05 932 2963.65 586 10460.42 756 5657.86 892 6258.41 520 11060.95 805 5362.94 627 8962.87 511 11056.62 730 4963.14 546 8261.07 488 13563.82 639 6761.4 746 5064.17 600 5358.15 559 7762.94 691 4861.53 553 8764.63 677 5863.81 780 4662.86 654 5062.84 663 7755.94 725 6259.06 643 8764.54 717 7864.36 739 5062.82 769 6264.79 883 4260.18 562 8461.54 768 8766.05  (PPB) AND  S .21 .76 6.6 2.22 2.74 1.0 .23 .25 .82 .56 .60 .02 1.77 .42 .17 .05 .50 .09 .12 1.17 .27 .24 .21 .11 .50 .1 .21 1.57 .82 .56 1.34 .22 .01 .91 .24 .56 .1 .33 .66 .22 .01 .51 .19 .37 .07 .12 .04 .14 .03 .01 .02 .19  HG 15 13 100 98 128 38 60 35 27 84 53 2 1 1 176 190 1 1 6 7 9 12 6 5 5 7 5 17 1 1 12 1 1 8 7 7 8 10 15 1 4 1 22 1 7 2 5 8 1 1 1 1  SI02 6 S CL 384 496 352 608 368 640 480 432 384 168 32  (WT.S) )  F HEXCL 1148 6. 3 280 4. 0 240 22. 336 2 0 . 412 3. 296 16. 396 19. 156 5. 6 328 19. 128 3. 64 2. 7  200 116 240 140 384 72 320 128 352 280 480 284 512 296 368 256 256 240 352 288 280 260 340 256 4 16 180 160 360 368 256 172 472 180 388 168 372 196 192 188 452 196 460 220 204 196 360 200 92 180 260 196 252 156 336 168 360 212 76 216 44 224 172 260 208 182 344 216 120 176 272 180 324 228 40 224 68 240 384 184 256  HEX10. 8. 4.7 3.2 5.6 10.1 6.2 7. 6.3 30. 10.  5.1 9. 2.8 6. 4.0 , 10. v . 20. 7.4 34.3 5. 14.0 6. 4.2 7.1 3.8 5. 5.7 5.8 4.6 6.5 12. 3. 4.4 12. 16.2 10. .3.6 12.0 3.6 6.0 16.0 3.5 3. 8 5. 4.1 7.2 6. 8.5 7. 11. 3.8 11.1 8. 8.5 5. 8.4 7.6 9. 2.8 7.0 11.0 1 2 . 3. 6.6 11.0 9. 4.7 11.0 3.6 4.4 14.0 6.2 6.8 8.6 3.3 9.2 5.6 8.5 3.8 9.0 1.7 6.2 4.3 7.4 1.6 5.6 15.0 4.9 4.6 6.2  FIGURE 79:  0  800ft  0  244m  Location of samples, Bethlehem-JA  (Geology, after Bethlehem 2400 l e v e l .  Mn in ig  Staff)  347  BETHLEHEM-JA ATOMIC  2400  ABSORPTION A N A L Y S I S (VALUES  u 151 154 159 163 168 171 173 175 177 180 182 185 187 189 192 195 198 200 202 205 208 211 213 215 219 222 225 228 231 236 239 242 247 249 251 255 258 260 262 264 268 274 276 278 280 282 284  LOC.COORD 200 550 650 450 500 700 500 550 6 50 700 400 400 350 700 800 800 750 750 650 550 450 350 700 800 400 300 300 600 650 850 850 350 250 500 600 800 500 250 900 350 200 150 50 50 965 650 350  LEVEL  600 450 450 450 500 400 400 350 350 500 500 400 450 300 300 400 350 250 250 550 550 550 200 200 600 600 500 600 550 350 250 650 550 300 300 500 600 450 200 150 500 550 375 525 75 75 225  IN  (HN03-HCL04  OIGESTION)  PPM)  CU  ZN  727.165 5400.781 5057.133 4675.551 2976.465 2307.012 6850.141 6172.984 212.518 169.646 3372.431 1133.037 148.990 4923.797 4282.523 845.344 1928.842 3546.295 1663.475 826.200 1302.155 1165.238 963.617 2236.109 3742.283 1850.313 4144.883 191.930 930.627 894.822 2357.317 1243.653 3505.272 194.792 3726.749 70.516 2091.526 398.575 902.378 2352.045 1300.885 3162.533 961.462 193.880 345.656 584.937 142.139  24.427 15.506 24.74<t 16.710 14.756 15.914 6.002 7.253 9.595 15.565 18.263 8.626 10.583 20.313 24.389 19.117 26.797 24.644 19.147 11.163 8.651 12.627 7.253 32.649 14.146 13.133 9.428 24.440 21.008 36.687 30.938 17.403 12.804 23.616 18.597 23.816 17.393 19.147 22.889 9 . 822 10.550 27.866 23.257 13.298 27.480 8.301 7.634  .  MN 173.045 113.540 204.737 15.362 101.506 127.696 182.486 92.945 83.159 117.562 90.269 143.241 114.537 183.304 199.272 164.380 190.946 196.705 115.141 86.117 72.561 94.135 135.702 258.323 82.272 116.957 139.543 218.679 160.783 400.762 213.153 123.026 131.872 248.972 182.668 197.186 135.855 135.855 158.595 90.278 86.749 221.243 212.995 92.967 195.428 84.496 90.419  AG 0. 0. 0. 0. 0. 0. 1. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.  0 0 0 0 0 0 162 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  NI 0. 0 0. 0 7 . 088 0. 0 1. 374 0. 0 0. 0 0. 0 0. 0 1 8 . 862 3 . 253 0. 0 0. 0 0. 0 6 . 870 8. 728 6 . 210 8 . 628 0. 0 0. 0 0. 0 Oi 0 0. 0 9 . 027 0. 0 0. 0 0. 0 9 . 310 6 . 210 8 . 861 5. 057 0. 0 0. 0 0. 0 0. 0 4 . 728 0. 0 0. 0 0. 0 0. 0 0. 0 0. 0 0. 0 0 . .0 0. 0 0. 0 0. 0  PB 0 .0 0 .0 0 .0 0 .0 0 0 .0 0 .0 0 .0 0 .0 0 .0  .0  0..0 0  0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 0 .0 0 .0  .  348  BETHLEHEM-JA SPECTROGRAPHS  2400  LEVEL  ANALYSIS (VALUES I N PPM)  SAMP. # 151 154 159 163 168 171 173 175 177 180 182 185 187 189 192 195 198 200 202 205 208 211 213 215 219 222 225 228 231 236 239 242 247 249 251 255 258 260 262 264 268 274 276 278 280 282 284  B  SR  0 700 0 800 0 600 10 600 0 800 101000 50 400 30 200 10 400 201500 0 800 10 200 10 7 0 0 10 500 01000 0 700 01000 15 7 0 0 0 700 10 8 0 0 101500 01500 50 200 151000 20 4 0 0 50 500 20 5 0 0 15 800 101000 20 800 01000 0 700 20 9 0 0 10 400 10 4 0 0 0 700 0 800 01000 01000 151000 0 800 15 6 0 0 0 700 0 600 101200 10 150 15 2 0 0  TI  IN -  700 50 800 50 1000 50 700 50 1000 50 2000 50 1000 50 800 50 600 50 1500 50 700 50 600 50 600 50 1000 50 1000 50 2000 50 2000 50 2000 50 1000 50 1000 50 1000 50 2000 50 1000 50 800 50 1500 50 1500 50 200 50 2000 50 1500 50 2001 50 2001 50 500 50 2001 50 1000 50 600 50 800 50 1000 50 1500 50 2001 50 2000 50 1500 50 1500 50 1000 50 1000 . 50 2000 50 700 50 600 50  V 30 30 60 30 40 40 50 20 20 500 30 30 30 40 50 60 50 40 30 30 40 50 20 40 50 40 30 50 50 70 70 30 50 30 20 30 30 40 50 60 40 50 30 30 50 10 10  BO  BA BIGA SN  0 700 020 0 8 600 020 0 10 500 020 0 1001000 020 0 0 600 020 0 300 4 0 0 020 0 200 400 020 0 2 0 0 500 020 0 0 500 020 0 0 100 020 0 10 600 020 0 0 400 020 0 0 400 020 0 50 200 020 0 7 600 020 0 0 500 020 0 10 500 020 0 0 200 020 0 0 600 020 0 15 5 0 0 020 0 01000 020 0 0 500 020 0 50 400 020 0 0 500 020 0 40 500 020 0 800 500 020 0 20 500 020 0 0 400 020 0 0 500 020 0 30 100 020 0 30 400 020 0 10 400 020 0 20 400 020 0 8 400 020 0 0 500 020 0 4 400 020 0 0 500 020 0 8 500 020 0 0 500 020 0 8 500 020 0 8 600 020 0 10 4 0 0 020 0 15 500 020 0 5 500 020 0 0 500 020 0 0 300 020 0 5 300 020 5  349  APPENDIX B Valley Copper (Sample locations and analytical results)  Bethsaida granodiorite | P 1 Leucocratic porphyry Y _ j Ultimate Pit Outline (0-3%Cu) Ore body Fault 7<? 98  140  «5  82J  158 6 0  LU  13  o Z1Z  no  35  I2«»  800 ft (Geology after Allen and Richardson, I970) FIGURE 80:  Location of samples, Valley Copper Suboutcrop Level  244m  V  351 V A L L E Y COPPER  SUBOUTCROP L E V E L  ATOMIC ABSORPTION A N A L Y S I S (VALUES I N PPM) #  1 4 6 8 11 14 17 19 21 24 26 29 32 35 37 40 43 46 49 52 55 58 60 61 63 66 68 71. 74 75 77 79 82 85 88 93 95 98 101 104 106 108 110 1 13 1 16 118 121 124 126 129 132 135 138 140 143 145 147 292 295 298 300  LOC .COORD 375 285 375 333 415 290 250 333 375 251 415 250 375 375 420 333 290 333 330 290 292 415 100 225 375 210 207 2 37. 228 236 375 174 50 175 84 174 255 225 402 250 265 255 334 390 270 435 350 305 432 4 27 345 327 4 50 4 50 362 280 327 475 415 290 2 92  212 218 131 175 175 131 257 95 260 95 135 217 95 50 225 134 175 217 260 257 95 95 180 220 175 135 260 2.60, 255 211 1 15 268 212 215 260 156 140 195 160 175 230 265 51 193 280 152 237 275 105 55 2 82 315 194 235 310 290 296 130 50 52 310  (UN03- UCL04 DIGESTION)  CU  ZN  MN  AG  5404.191 3568.929 3424.768 829.821 1529.498 2122.148 3117.681 1389.874 5564.070 2214.659 2022.325 7350.621 1765.783 699.095 6522.184 4804.105 5099.324 4478.520 4792.617 2447.569 2004.448 1347.661 54.337 2724.894 6646.320 1542.012 2147.808 226.1,. 0 61. 3862.698 2767.040 2158.081 359.896 11.278 45.865 151.450 1247.331 3631.027 2154.846 7406.465 1019.937 4173.414 4311.160 3036.520 2370.130 1714.048 7005.930 5195.066 1898.817 2986.460 538.624 2219.927 3415.737 3723.940 6903.949 6627.395 2336.121 3124.426 6159.180 10941.070 1537.919 2062.914  41.337 12.443 11.441 17.405 26.601 16.004 20.009 17.981 10.356 14.606 27.067 26.359 18.693 24.536 19.101 37.709 15.416 14.227 14.575 11.570 21.236 16.976 26.230 9.919 12.663 11.153 17.437 17..756 5.785 20.729 35.899 34.630 24.788 28.012 24.860 18.812 10.780 16.724 24.393 14.428 14.971 21.889 14.642 25.393 24.393 14.300 18.781 24.444 3.732 11.248 14.957 22.86 1 23.799 33.801 15.101 23.900 23.395 16.632 21.301 25.041 27.928  493.321 202.550 278.611 161.065 203.739 201.362 213.672 74.271 53.770 964.061 235.323 288.146 166.877 158.746 268.717 120.346 154.502 81.282 73.167 300.241 311.999 147.196 286.069 151.037 161.453 138.009 370.903 282.751.. 132.292 200.571 238.150 348.179 264.405 356.369 197.015 183.187 292.916 207.586 233.459 235.272 242.545' 249.119 237.086 223.706 337.980 279.424 138.911 213.656 391.586 306.907 137.547 285.031 • 272.721 357.867 291.788 266.047 308.047 323.104 192.675 359.518 385.779  1.308 0. 844 0.0 0.0 0.452 1.060 0.0 0.0 1.329 0.0 0.0 2.699 0.0 0.0 0.0 0.0 1.208 0.080 0.0 0.0 0.0 0.0 0.0 0.603 1.270 0.0 0.0 1.518 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1. 179 0.0 0.658 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0. 536 0.0 0.0 0.0 0.0 0.901 4. 944 0.0 0.0 0.0 0.0 0.0 0.0  NI  1.003 0.617 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0  PB  0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0  352 VALLEY COPPER SUBOUTCROP SPECTROGRAPHS  LEVEL  ANALYSIS (VALUES I N PPH)  SAMP. # 1  1*  6 8 11 14 17 19 21 24 26 29 32 35 37 40 43 46 49 52 55 58 60 61 63 66 68 71 74 75 77 79 82 85 88 93 95 98 101 104 106 108 110 113 116 118 121 124 126 129 132 135 138 140 143 145 147 292 295 298 300  B  SR  15 150 10 200 101500 0 500 0 500 10 400 10 4 0 0 0 600 0 300 15 300 0 500 15 200 10 500 0 800 0 300 0 300 0 300 . 0 300 10 400 20 400 10 200 0 700 0 700 20 400 15 300 0 300 20 300 10 400 20 300 -10 500 0 500 0 700 0 800 0 500 0 500 10 500 10 4 0 0 0 500 0 400 0 400 0 400 0 500 20 300 0 500 15 400 10 300 10 200 10 500 20 200 20 300 0 400 0 400 01500 0 400 151000 0 500 0 400 10 500 10 400 20 400 0 500  TI  .  1000 1500 2000 600 500 1000 1000 700 1000 1500 2000 2000 1000 700 800 1000 500 500 1000 1000 1000 1500 800 800 1000 800 2001 800 1500 800 1500 500 500 1000 700 700 800 700 2001 500 1000 1000 1500 1000 500 2000 500 500 2001 1000 700 2000 1000 800 600 700 700 1000 1000 1000 2000  IN 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 - 50 50 50 50 50 50 50 50 50 50 50 - 50 50 50 50 50 50 50 50 50 50 50  V 50 30 30 20 20 30 40 20 30 40 30 40 20 20 40 30 20 20 30 50 30 20 20 30 40 15 30 20 30 30 30 20 20 20 20 20 30 20 50 20 40 30 30 40 20 40 30 20 30 30 30 40 40 30 30 30 30 30 40 30 30  BO  BA BIGA SS  10 500 10 4 0 0 10 500 0 500 0 700 0 800 5 700 01000 5 600 10 500 0 700 15 5 0 0 0 500 0 500 4 600 0 700 0 500 10 500 20 500 0 500 0 400 01000 0 600 5 600 60 500 100 500 80 600 400 500 20 800 0 800 01000 4 700 0 700 0 800 0 500 3 0 500 4 500 0 800 40 600 0 500 0 500 0 700 0 600 0 600 5 500 0 500 5 500 0 500 40 200 0 400 10 500 8 600 8 500 150 5 0 0 100 400 6 700 0 600 15 4 0 0 30 600 201000 10 500  020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  1 Bethsaida  [  granodiorite  | P | Leucocratic porphyry «' j  Ultimate Pit Outline (o-3%Cu)i  £E> vw*  Ore body Fault  '8o 8<1  86  S3  r-(  X LU \  \ 213  \  ^ ^  3fc  I30 800 ft si 244m  (Geology after Allen and Richardson, I970)  FIGURE 81:  Location of samples, Valley Copper 3600 Level.  I  354  VALLEY  COPPER 3600 L E V E L  ATOMIC ABSORPTION A N A L Y S I S (VALUES IN PPM)  . # 2 5 7 9 12 15 18 20 22 25 27 30 33 36 38 Ul 44 47 50 53 56 59 62 64 67 69 72 76 78 80 83 86 89 91 94 96 99 102 105 107 109 111 114 117 119 122 125 127 130 133 136 138 141 143 146 293 296 299 301  LOC.COORD 375 285 375 333 415 290 250 333 375 251 415 250 375 375 420 333 290 333 330 290 2 92 415 225 375 210 207 237 236 375 174 50 175 84 100 174 255 225 402 250 265 255 334 390 270 435 350 305 432 427 345 327 450 450 362 280 475 415 290 292  212 218 131 175 175 131 257 95 260 95 135 217 95 50 225 134 175 217 260 257 95 95 220 175 135 260 260 211 115 268 212 215 260 180 156 140 195 160 175 230 265 51 193 280 152 237 275 105 55 282 315 194 235 310 290 130 50 52 310  CU 4795.492 4168.574 2442.377 3934.639 4179.773 8915.070 8672.949 4879.008 3160.536 1454.594 3016.187 2250.734 3533.437 1780.947 6159.813 1574.561 4672.180 3176.616 3533.487 3929.087 6374.113 454.177 2952.335 4095.922 435.083 2656.572 4297.684 956.369 2489.233 112.783 81.165 67.711 10.955 926.470 1145.979 449.402 2856.325 3900.533 4551.625 4783.902 1532.364 6951.875 5727.238 409.435 4157.574 3061.598 4183.988 3879.675 396.049 3682.602 2774.952 3723.940 958.333 6627.395 2394.440 3801.205 306.953 1702.081 897.856  (HN03- HCL04 DIGESTION) ZN  16.992 5. 393 15.632 4.336 14.303 17.008 15.232 5.995 22.837 16.379 23.451 19.959 8.477 20.209 13.403 15.833 16.473 10.639 17.532 17.804 13.313 20.864 10.427 25.981 19.545 17.724 18.693 10.639 13.671 24.232 17.024 28.875 31.594 3.886 30.955 24.138 19.840 126.356 11.221 16.016 10.581 1031.626 11.369 35.459 22.595 148.565 15.826 9.530 9.987 17.849 16.683 23.799 93.349 15.101 22.299 34.554 1.9.425 19.254 27.341  MN  340.455 217.663 147. 196 32.784 231.696 141.065 20 1. 757 145.086 201.757 131.531 162.807 203.739 193.859 226.069 120.912 108.478 156.816 99.117 128.111 167.266 144.51 1 171.151 153.346 88.692 335.325 471.050 248.686 212.876 112.991 282.336 609.589 298.569 430.566 527.682 246.925 244.004 262.720 156.575 124.652 202.960 423.182 322.942 155.022 452.094 273.836 263.459 238.540 282.412 246.925 352.383 206.161 272.721 609.424 291.788 61 1.269 499.842 296.892 174.170 420.536  AG 1,. 194 0,.852 0,.0 0,.592 0,, 428 1.,654 0., 847 0..656 0., 509 0,,0 0.,080 0.,0 0.,0 0.,0 0. 375 0. 0 0. 0 • 0.0 0. 107 0. 0 0. 0 0. 0 0. 0 2. 291 0. 0 0. 0 0. 0 0. 0 0. 0 0. 0 0. 0 0. 0 0. 450 0. 0 0. 0 1. 057 0. 637 1. 528 0. 0 0. 0 0. 0 0. 0 3. 034 0. 0 0. 502 0. 0 0. 0 1. 318 0. 936 0. 0 0. 849 0. 0 0. 0 4. 944 0. 0 0. 0 0. 0 0. 0 0. 0  HI  0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 CO CO CO  0.0  PB CO CO  0.0 0.0 CO  0.0 CO CO CO CO CO  0.0 CO  0.0 0.0 CO CO  CO CO CO CO CO CO CO  0.0  0.0  0.0  CO CO CO  0.0 CO CO CO CO CO CO CO  0.0  0.0 CO  CO CO CO CO  0.0 0.0 CO CO  0.0 CO  0.0 CO  0.0 CO  0.0  CO CO CO CO CO CO CO CO CO  CO CO CO  0.0  0.0  CO  0.0 CO  0.0 0.0 5.730  CO CO CO CO CO  0.0 0.0 0.0  0.0  CO  CO CO CO CO CO  0.0 0.0 0.0  0.0 CO  CO  CO  355 VALLEY COPPER 3600 L E V E L ATOMIC ABSORPTION A N A L Y S I S (TOTAL DIGESTION) (VALUES IN WEIGHT %) SAMP, t 2 5 7 9 12 15 18 20 22 25 27 30 33 36 38  <n  un  47 50 53 56 59 62 64 67 69 72 76 78 80 83 86 89 91 94 96 99 102 105 107 109 111 114 117 1 19 122 125 127 130 133 136 138 141 143 146 293 296 299 301  CAO 0 " 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0' 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  1.066 2.202 1.336 0.469 1.634 1.307 1.591 1.563 1.805 1.052 1.734 1.890 1.620 1.876 1.151 0.767 1.023 1.037 0.668 1.606 1.350 1.947 2.032 0.554 2.202 3.638 1.847 1.876 1.321 2.629 4.419 2.188 2.657 2.316 2. 103 1.847 1.918 1.137 1.137 2.245 2.771 2.018 0.952 2.629 2.018 2.501 1.705 2.984 2.359 2.018 3. 169 2.700 2.771 3.979 2.487 2.998 2.416 1.8.05 1.762  MGO 0. 383 0.428 0.371 0.248 0.428 0,371 0.462 0. 304 0.675 0.428 0.473 0.405 0.270 0.315 0.304 0.332 0.371 0.281 0.562 0.416 0.439 0.371 0.315 0.295 0.360 0.409 0.4 39 0.464 0.405 0.360 0.585 0.270 0.518 0.392 0.462 0.422 0.411 0.360 0. 360 0.377 0.428 0.563 0. 326 0.822 . 0.529 0.490 0.540 0.433 • 0.280 0.360 0.473 0.546 0.552 0.231 0.523 0.439 0.371 0.473 0.585  FE203  NA20  1.655 1.655 1.241 1.103 2.207 1.793 2.207 1.310 2.407 1.517 1.724 1.586 1.241 1.028 1.862 0.897 1.724 1.379 1.931 2.207 1.793 1.103 1.517 1.483 1.793 1.862 2.414 2.345 1.172 1.586 1.103 1.862 1.862 1.931 1.207 1.931 2.207 1.517 1.517 1.828 2.138 2.483 1.793 3.310 2.276 2.483 2.345 1.897 1.103 1.793 2.345 2.669 2.834 1.483 2.359 2.586 1.207 1.724 2.690  1 .-914 1.352 3.175 2.237 2.165 1.539 2.357 2.405 3.415 4.906 3.535 3.127 2.492 3.583 2.453 3.583 2.386 2.116 2.646 2.049 1.861 3.175 2.958 0.322 3.896 2.973 2.391 3.511 2.694 4.906 0.202 4.570 4.570 3.896 0.890 4.666 3.131 2.621 2.621 1.756 1.914 1.318 1.669 3.824 2.742 2. 405 1.785 1.299 2.573 4.089 3.040 2.650 2.453 1.231 3.415 2.650 3.088 6.975 3.656  K20 3.955 3.343 2.401 3.719 3.249 3.013 2.872 2.354 2.646 2.024 2.363 2.345 2.599 2.213 2.024 1.648 3.183 3.861 3.531 2.693 3.154 1.460 2.401 2.806 2.213 1.911 3.305 2.175 2.589 1.761 2.335 2. 147 1.864 2.024 3.908 1.742 3. 154 3.644 3.644 3.089 3.390 4.218 3.004 2.260 3.296 3.625 3.719 3.089 1.902 1.911 3.041 4.218 2.806 2.448 3.220 3.315 2.637 1.648 3.060  356  V ALLEY COPPER 3600 L E V E L SPECTROGRAPHIC  ANALYSIS (VALUES  SAMP. # 2 5 7 9 12 15 18 20 22 25 27 30 33 36 38 41  B  IN SR  PPH) TI  IN  V  HO  BA BIGA SN  47 50 53 56 59 62 64 67 69 72 76 78 80 83 86 89 91 94 96 99 102 105 107 109 111 114 117 119 122 125 127 130 133  0 300 102001 0 400 0 300 15 300 10 600 101000 0 200 0 500 0 600 0 500 10 500 10 500 0 500 0 300 0 400 0 500 0 300 0 400 10 500 10 400 0 800 20 400 20 150 10 400 0 400 01500 15 400 0 500 0 600 60 500 0 700 01500 10 700 0 600 0 800 102001 10 300 0 800 0 900 15 400 15 300 10 400 01000 01500 10 200 0 300 20 800 20 400 10 300  1000 1000 2000 1000 1000 1000 1000 800 700 800 1500 2000 1000 700 500 1000 1000 600 1000 2000 1000 1500 800 2000 900 1500 1000 800 700 800 1000 1000 700 800 1000 1000 1000 600 800 1000 1000 1000 800 1000 500 1000 2000 1000 1000 700  50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50  20 0 400 50 0 400 20 20 500 20 40 400 30 0 600 40 0 800 40 0 500 30 0 400 20 5 500 15 20 500 30 15 5 0 0 30 0 500 40 0 400 20 0 700 20 50 5 0 0 4 500 15 40 10 500 20 0 400 40 0 500 50 0 500 40 0 500 20 5 600 20 15 6 0 0 50 100 500 20 5 600 30 40 600 30 200 500 30 5 800 20 0 800 20 0 500 30 0 500 20 0 700 20 0 600 20 0 500 20 30 6 0 0 30 0 500 30 5 600 20 0 500 30 0 500 30 0 600 30 20 700 50 0 700 30 20 5 0 0 30 10 600 30 4 0 600 30 20 400 40 30 500 30 151000 30 0 600 40 4 500  020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020 020  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  136 138 141 143 146 293 296 299 301  01000 01500 10 400 151000 0 500 0 600 10 500 01000 20 500  1000 1000 2001 600 800 700 1000 700 2001  50 50 50 50 50 50 50 50 50  50 15 6 0 0 40 8 500 30 40 500 30 100 400 40 0 700 30 5 400 0 400 30 20 101000 50 20 800  020 020 020 020 020 020 020' 020 020  0 0 0 0 0 0 0 0 0  nn  357  VALLEY COPPER 3600 (VALUES I N PPM SAMP. • 2 5 7 9 12 15 18 20 22 25 27 30 33 36 38 11 nu  '  47 50 53 56 59 62 64 67 69 72 75 78 80 83 86 89 91 94 96 99 105 107 109 111 114 1 17 1 19 122 125 127 130 133 136 138 141 143 146 293 296 299 301  RB  LEVEL  EXCEPT FOR SR  73 328 69 2 2 2 3 47 501 67 369 65 269 62 72 69 883 61 483 59 625 50 729 45 581 59 496 50 443 53 580 62 334 44 496 70 681 72 342 82 440 71 627 61 346 34 800 63 495 76 161 52 54 9 64 432 72 1680 52 585 41 542 43 839 87 464 62 715 45 1460 52 675 49 741 39 103 1 55 2 4 0 2 58 883 65 871 82 462 77 278 55 272 48 908 59 1471 78 199 76 279 60 900 48 393 75 276 61 893 70 1386 70 377 59 759 71 624 61 681 58 681 36 765 70 423  3B/SR  HG  SI02  (PPE) AND S  22267.37 .27 3166.8 .31 9372.8 .21 18173.94 .46 24164.23 .47 86166.17 .39 7865.69 .84 12666.71 .23 9466.96 . 17 6968.93 .12 7771.39 . 13 11967.44 . 12 1 1 3 7 0 . 8 0 .21 9167.93 . 17 18668.33 .27 8975.44 . 10 10371.47 .26 2175.06 .32 18669.69 .12 11365.92 .30 17668.28 .28 4271.41 .05 12765.96 .38 47270.43 .40 9565.44 .06 14862.26 . 36 4 3 6 4 . 8 9 1.17 8965.55 .47 7674.61 .33 5165.00 .02 1 8 6 6 3 . 17 .03 8765.46 .04 3166.68 .09 7763.57 . 16 6668.15 . 17 3865.95 .04 2364.23 .28 6671.47 .23 7566.72 .20 17761.76 .20 27763.72 .28 20274.62 .57 5368.51 .04 4062.77 .20 39269.75 .36 27267.25 .36 6761.18 . 10 12271.09 . 11 2 7 1 6 3 . 15 .44 6 8 6 0 . 8 8 2.63 5 1 5 9 . 0 7 1.89 1 8 6 6 0 . 12 .33 7 8 7 1 . 7 4 1.07 11362.01 .99 9057.98 .24 8566.36 . 18 4769.89 . 16 16562.48 .18  SI02 6 S  HG  CL  1 1 1 2 5 1 1 1 6 7 1 2 1 10 10 1 1 1 1 1 7 3 5 22 6 5 46 1 2 1 7 1 1 1 1 7 4 12 4 1 1 1 'i 2 7 26 7 1 1 1 1 1 5 1 1 1 6 1 5  490 256 220 312 228 344 220 2 32 240 260 196 190 220 224 364 320 296 480 276 224 172 460 280 396 316 220 222 320 225 220 280 296 270 320 376 340 141 68 232 208 264 216 204 196 220 192 175 168. 212 200 210 212 152 181 176 326 200 176  (HT.*) )  F 409 440 616 460 406 4 12 288 694 304 348 240 540 436 212 480 324 408 436 328 312 236 292 306 360 236 348 318 272 528 152 376 312 264 3 36 220 328 600 408 600 285 408 404 700 448 660 564 452 472 252 700 653 624 460 725 604 270 265 700  10.7 2.3 2.2 4. 2 4.7 2.2 1.,5 7.,2 3.. 1 7,.0 3 .0 2,. 6 2.,2 2.0  3. 2 2.7 6.3 5.6 7. 1 5.4 5.6 1.8 1.2 5.3 2.3 7.2 1.4 1.8 1.9  1.0 2.0 1.4 3.6 1.0 1.1 2.4 1.0 '1.3 1.0 2.5 1.8 1.3  11.0 10.0 9.0 5.2 10.5 10.3 7.3 8. 1 9.8 6.2 6.0 7.0 5.1 6.2 2.5 4.6 5.6 6.3 2 5 4 3 5.4 2.7 6.0 6.8 8.2 7.8 5.3 4.3 4.1  5.0 6.5 6.4 7.4 5.2 4.8 4.3 4. 1 4. 1 3.9 4.8 6.2 3.5 3.6 6. 5. 5.8 5.2 1.5 1.8 4.0 3.5 3.7 4.2 4.5 4.6 6.0  I  ] Bethsaida  granodiorite  A  ( P 1 Leucocratic porphyry 3t>2.  « ' _ _ ! Ultimate Pit Outline (o-3%Cu)  144  137  N  62> Ore body Fault 8'  81  84  <?2 \  \  %  2  \  ^- ^ V  _____  —  12./ 0  (Geology after Allen and Richardson, 1970) FIGURE 82:  Location  of samples, V a l l e y Copper 3300 Level  800 ft 244 m  359  VALLEY COPPER 3300 LEVEL ATOMIC ABSORPTION ANALYSIS (VALUES  » 3 10 13 16 23 28 31 34 39 42 45 48 51 54 57 65 70 73 81 84 87 90 92 97 100 103 112 115 120 123 128 131 134 137 139 142 144 148 294 297 302  LOC. COORD 375 333 415 290 375 415 250 375 420 333 290 333 330 290 292 375 285 237 174 50 175 84 100 255 225 402 334 390 435 350 432 427 345 327 450 450 362 327 475 415 292  212 275 175 131 260 135 217 95 225 134 175 217 260 257 95 175 218 210 268 212 215 260 180 140 195 160 51 143 152 237 105 55 282 315 194 235 310 296 130 50 310  (HN03-HCL04 DIGESTION)  IN PPM )  cu 5257.129 2819.834 3940.172 3807.497 1046.838 5842.004 4154.602 225.977 3101.618 665.327 4646.469 7605.289 3489.944 4068.029 3354.378 1029.696 6708.621 102.970 150.950 16.046 1138.918 27.477 52.227 406.281 3564.146 2653.940 1568.299 3538.494 2111.572 8984.219 1335.231 3172.235 2321.562 5557.781 9635.844 2589.996 953.776 382.764 2704.168 1584.689 949.996  IH 14.454 11.874 20.948 16. .191 17.580 5.315 24. 143 11.039 18.255 8.641 25.673 14.682 4.953 17.756 20.009 19.512 12.958 25.132 30.639 24.411 67.2L8 25.620 25.620 3. 080 18.797 10.621 13.078 15.260 13.078 12.815 17.127 8.755 • 13.162 9. 147 8.767 22.620 6.308 24.189 37.064 4.759 27.271  MN 185.996 172.318 205.323 132.673 180.903 192.677 190.316 232.502 207.705 227.675 231.696 109.230 311.578 182.274 163.389 151.037 115.626 268.305 289.601 238.150 325.108 323.710 293.294 256.823 292.916 200.119 445.023 191.277 151.237 166.782 262.535 375.628 170.258 242.545 261.982 265.677 311.090 248.387 233.475 322.936 349.847  AG 0.901 0.294 0.683 0.0 0.844 0. 616 0.0 0.0 0.0 0.0 0.267 0.987 1.208 0.0 0.281 0.214 0.0 0.0 0.0 0.0 0.0 0.0 1.277 0.0 0.0 0.0 0.0 0.797 0.0 1.562 5.943 0.0 CO 1.092 4.588 0.0 0.0 0.0 0.0 0.0 0.0  '  NI  PB  1.505 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 CO 0.0 0.0 0.0 0.0 0.0 CO 0.0 0.0 CO 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 CO 0.0 0.0 - 0.0 0.0 0.0 0.0  0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 .0 0.0 CO 0 .0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0  360  VALLEY  COPPER 3300 LEVEL  SPECTROGRAPHIC  ANALYSIS (VALUES IN PPM)  SAMP. # 3 10 13 16 23 28 31 34 39 42 45 48 51 54 57 65 70 73 81 84 87 90 92 97 100 103 112 115 120 123 128 131 134 137 139 142 144 148 . 294 297 302  B  SR  0 500 0 600 10 400 0 400 10 700 10 300 02001 0 500 0 400 0 300 0 500 0 400 10 500 0 500 0 700 0 400 0 400 01000 10 700 10 800 10 400 10 700 0 600 . 1 0 700 0 400 0 400 15 400 102001 01000 10 400 0 500 20 400 0 500 0 700 10 100 0 500 20 400 0 600 0 400 20 400 0 800  TI 1000 1000 2000 1000 500 800 500 1000 1000 700 1000 800 500 1000 1000 1000 1500 1500 1500 500 700 800 1000 1000 800 1000 700 1000 500 500 500 1000 1500 1000 1500 1500 1000 600 700 1000 2000  IN 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 • 50 50 50 50 50 50 50 50 50 50 50 50 50 50  V  MO  BA BIGA SN  30 0 500 020 30 4 500 020 30 10 600 020 30 30 700 020 30 01000 020 40 0 500 020 20 0 500 020 20 0 400 020 40 30 400 020 20 0 600 020 40 10 500 020 40 0 500 020 30 0 500 020 30 0 500 020 40 5 800 020 20 0 600 020 40 15 600 020 30 0 900 020 30 3 600 020 15 0 700 02C 10 5 300 015 20 0 500 020 30 0 500 020 20 3 400 020 30 0 500 020 30 0 600 020 30 0 500 020 40 300 700 020 30 20 500 020 40 0 500 020 30 20 800 020 40 0 600 020 30 20 600 020 50 5 500 020 50 8 500 020 30 15 500 020 40 6 500 020 20 15 800 020 20 01000 020 30 02000 020 40 30 700 020  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 0 0 0 0 0  APPENDIX C Lornex (Sample locations and analytical results)  FIGURE 83 Location'iof samples.  Lornex Surface ( i n pocket)  363  LORNEX  SURFACE  SAMPLES  ATOMIC ABSORPTION  (TOTAL DIGESTION -RAPID TEFLGN TUBE PROCEDURE)  (VALUES SAMP. H LOC.COORD 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS •72 LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS 72LS  72705540393 72805440393 72905550370 73005360414 73105310424 73203100465 73302970468 73403010456 7350294 0450 73602830461 73702750459 73802730452 73902670442 74002620435 74102770425 74203100455 74303110426 74403100435 74502570423 74602550407 74702170464 74803050 44 74903130478 75002920481 75102800495 75202600 95 75302900600 75403020580 75502330606 75602210612 75701920630 75801870614 75901920582 76001900560 76101820521 76202220545 76302520 56 76402610 40 76506270618 76606170575 76706160567 . 76806120 56 76906280584 77006660572 77106460577 77207030486 77306830 92 77406960527 77506790544 77606620552  IN PPM  FOR TRACE ELEMENTS AND WT.  CU  ZN  FE203  16 13 26 11 414 31 6 30 7 4 7 8 18 2 5 3 189 48 4 4 27 15 32 120 15 6 3 4 8 76 120 69 14 423 68 80 2 6 5 9 29 10 15 11 12 135 6 4 8 538  28 35 25 24 41 27 19 25 28 17 28 30 25 35 39 17 29 36 34 33 32 34 26 27 30 28 15 19 24 22 22 26 26 28 24 27 26 23 38 40 35 36 27 26 27 50 34 18 33 24  1.9 2.1 3.4 2.0 2.1 1.6 1.3 1.4 1.2 1.3 1.5 .1.8 1.4 1.4 1.3 2.0 1.7 1.4 1.3 1.5 1.6 1.5 1.5 1.4 1.4 1.4 1.3 1.6 1.7 1.3 1.5 1.4 1.4 1.5 1.5 1.5 1.5 1.5 1.8 1.9 1.8 2.0 1.9 2.7 2. 1 4.0 1.2 2. 1 1.3 1.8  CAO 3.3 3.3 3.6 3.4 3.0 2.4 2.5 2.4 2.4 3.0 2.5 2.7 2.4 2.5 2.7 4.1 2.8 2.4 2.4 2.5 2.6 2.4 2.4 2.4 2.8 2.6 3.0 4.0 4.0 2.5 2.2 2.4 2.8 2.4 2.5 2.4" 2.6 2.6 3.3 3. 1 3.0 3.2 2.5 4.2 3.9 4.8 4.2 3.7 3.2 3.7  NA20 3.9 4.0 4.0 3.5 3.7 4.1 4.3 4.3 3.8 4.3 3.9 4.2 4.2 4. 1 4.5 4.8 4.4 3.7 4.0 3.7 4.0 3.8 4.0 3.9 4. 1 4.2 4.2 4.7 4.1 3.8 3.8 3.8 4.2 4.1 3.8 3.7 3.7 3.5 3.6 3.3 3.3 3.9 4.1 3.9 4.0 2.8 4.1 3.8 3.5 3.2  K20 1.4 1.3 1.3 1.6 1.4 1.5 .5 1.4 1.5 .1 1.6 2.2 1.8 1.3 1.5 .3 1.2 1.7 1.4 1.4 1.5 1.6 1.5 1.5 1.5 1.6 .2 .7 1.5 1.4 1.5 1.7 .3 1.6 1.6 1.6 1.4 1.5 1.3 1.5 1.5 1.6 1.7 2.2 1.5 1.7 .4 1.0 .5 1.6  % FCR MAJOR ELEMENTS)  S A M P , k LOC.COORD 72LS 77706250595 72LS 77805170567 7 2 L S 7 7 9 0 5 0 2 0 47 72LS 78005000365 72LS 78104310507 72LS 78204960322 72LS 78304680295 72LS 78404570215 72LS 78504660219 72LS 78604800305 72LS 78704520209 72LS 78804990300 72LS 78905120365 72LS 79004150385 72LS 79104720428 72LS 79204580487 72LS 79305110330 72LS 79404400486 72LS 79503940463 72LS 79604850385 72LS 79704830447 72LS 79804460245 72LS 79905150348 72LS 80004170364 72LS 80103530483 72LS 80205020385 7 2 L S 8 0 3 0 4 2 1 0 48 72LS 80503990212 7 2 L S 8 0 6 0 4 5 4 0 45 72LS 80704010528 72LS 80804150214 72LS 80904200527 72LS 81004980272 72LS 81103970549 72LS 81204910298 72LS 81306450519 72LS 81506060525 72LS 81606200493 72LS 81706540490 72LS 81804600464 72LS 81904920423 72LS 82004750465 72LS 82106530560 72LS 82206000560 72LS 82306010550 72LS 82405730550 72LS 82505520535 72LS 82605400499 72LS 82705400468 72LS 82804330348 72LS 82906300590 72HS 8 8 4 0 2 9 5 0 3 1 6 72HS 8 8 9 0 2 8 6 0 3 6 2  CU 14 7 66 372 265 1520 1290 546 2100 2900 1400 3260 510 228 67 128 760 1530 5000 1130 136 580 18 1470 11 254 3500 45 5500 6000 330 105 2020 166 4360 35 33 18 13 1220 1060 93 97 13 7 18 11 178 7 600 20 10 20  ZN 42 31 31 57 45 37 22 20 31 19 17 46 47 22 43 210 85 55 55 41 52 18 41 28 16 39 14 33 33 82 15 53 20 43 28 24 50 25 27 99 60 99 38 31 28 27 37 24 33 23 22 27 . 24  FE203 2.3 1.8 1.3 1.4 2.3 1.0 .8 1.2 1.3 .6 1.6 .8 2.6 0.9 2.5 3.3 3.0 2.5 2.1 2.4 2.9 .6  l.l  1.9 2.2 2.8 1.2 1.5 1.7 2.7 1.0 2.8 0.6 2.3 0.8 2.6 2.8 2.5 2.7 2.4 2.8 3. 1 3.6 2.5 2.1 2.6 2.5 2.4 2.4 1.0 2.6 2.2 1.6  CAO 3.6 3.4 3.5 3.2 2.9 2.8 2.5 3.0 4.3 2.5 2.1 2.6 3.6 2.4 3.3 5.4 2.5 2.9 2.2 2.7 3.2 2.5 4.7 1.6 3.5 3.3 2.3 2.2 2.4 2. 6 1.9 3.0 2.4 2.4 2.1 3. 8 3.4 3.4 3.6 2.5 2.8 3. 7 3.9 3.2 2.7 3.7 3.5 3.0 3.0 2.2 5.0 3.0 2.4  NA20 3.8 3.8 4.4 4.3 3.5 3.9 2.7 1.4 .5 3.0 2.2 3.3 4.0 2. 1 4.1 3.8 4.0 4.2 2.8 3.7 3.8 4.0 4.9 3.5 4.3 3.7 1.8 4.3 1.1 1.5 3.7 3.9 2.8 3.7 3.7 4.1 4.0 4.3 4.3 3.7 3.7 4.0 3.8 3.9 3.8 3.8 4.1 2.9 4.0 3.2 3.7 4.4 3.8  K20 1.3 1.0 .5 .8 1.6 .5 1.0 2.4 3.7 .8 1.8 .8 1.9 1.9 2.1 1.6 1.3 1.6 1.9 2.0 1.7 1.9 .5 2.3 1.5 2.2 2.1 1.7 2.7 1.8 1.2 1.5 .8 2.0 1.0 .4 1.9 1.3 1.8 1.8 1.6 1.3 1.6 1.5 1.6 1.5 1.6 1.9 1.4 1.7 2.2 1.5 1.3  365  LORNEX  SURFACE  ATOMIC SAMP.  «  SAMPLES  ABSORPTION ANALYSIS (VALUES IN PPM)  LOC.COORD  727 0 728 0 7 29 0 730 0 731 0 732 0 733 0 7 3* 0 735 0 736 0 737 0 738 0 739 0 740 0 741 0 742 0 743 0 744 0 745 0 746 0 747 0 748 0 749 0 750 0 751 0 752 0 753 0 754 0 755 0 756 0 757 0 758 0 759 0 760 0 761 0 762 0 763 0 764 0 765 0 766 0 767 0 768 0 769 0 • 770 0 771 0 772 0 773 0 774 0 775 0 776 0 777 0  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  AG  0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2.500 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.500 0.0 0.0