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Minor elements in sphalerite and their implications for metallogenesis of carbonate-hosted zinc-lead… McLaren, Graeme Peter 1978

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MINOR ELEMENTS IN SPHALERITE AND THEIR IMPLICATIONS FOR METALLOGENESIS OF CARBONATE-HOSTED ZINC-LEAD DEPOSITS OF THE YUKON TERRITORY AND ADJACENT DISTRICT OF MACKENZIE by GRAEME PETER MCLAREN B. S c . , U n i v e r s i t y o f T o r o n t o , 1974 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n THE FACULTY OF GRADUATE STUDIES (Department o f G e o l o g i c a l S c i e n c e s ) We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o t he r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA May, 19 78 © Graeme P e t e r M c L a r e n , 1978 In presenting th i s thes is in pa r t i a l fu l f i lment of the requirements for an advanced degree at the Univers i ty of B r i t i s h Columbia, I agree that the L ibrary sha l l make it f ree ly ava i l ab le for reference and study. I further agree that permission for extensive copying of th is thesis for scho lar ly purposes may be granted by the Head of my Department or by his representat ives. It is understood that copying or pub l i ca t ion of th is thes is for f inanc ia l gain sha l l not be allowed without my writ ten permission. Depa rtment The Univers i ty of B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1WS Date y9^?/? <^ /9 y 95># i i ABSTRACT Minor element concentrations i n s p h a l e r i t e from the newly discovered carbonate-hosted zinc-lead deposits i n the Yukon T e r r i t o r y and adjacent D i s t r i c t of Mackenzie have been determined to define the metallogeny of t h i s remote region of the Canadian c o r d i l l e r a . Concentrations of s i l v e r , cadmium, cobalt, copper, i r o n , manganese, n i c k e l , lead, and mercury.in s p h a l e r i t e were analyzed i n 166 specimens from 48 deposits; an a d d i t i o n a l 13 elements were investigated at a q u a l i t a t i v e l e v e l . Minor element data defines two ages of regional metallogeny; d i f f e r e n t mineralizing processes also might be represented by these two events. Sphalerite i n the northern c o r d i l l e r a i s generally enriched i n copper, lead, and mercury, and depleted i n i r o n , r e l a t i v e to other d i s t r i c t s contain-ing s i m i l a r zinc-lead deposits. Iron contents vary sympathetically with darkness of colour i n s p h a l e r i t e . Minor element v a r i a t i o n s within si n g l e hand specimens, and a n a l y t i c a l v a r i a t i o n s , are both i n s i g n i f i c a n t r e l a t i v e to between-specimen v a r i a t i o n s , as revealed by analyses of variance. Minor element v a r i a t i o n s within si n g l e deposits are small r e l a t i v e to between-deposit v a r i a t i o n s ; therefore, each deposit i s characterized by the minor element assemblage of the s p h a l e r i t e i t hosts. Regionally, s p h a l e r i t e occurrences i n carbonate host rocks (dominantly dolomites) occurs as b r e c c i a matrix, vein, and fracture f i l l i n g s . Two major age groups of host rocks, Proterozoic to Lower Cambrian, and Middle Ordovician to Devonian, are separated by an Upper Cambrian to Middle Ordovician unit that i s bounded by unconformities and i s r e l a t i v e l y barren of mineral occurrences. Linear regression analysis of minor element r e s u l t s indicates d i s t i n c t l y d i f f e r e n t trends for each age group. P r o b a b i l i t y graph analysis of a l l minor i i i element contents define bimodal d i s t r i b u t i o n s consisting of r e l a t i v e l y 'enriched' and 'depleted' populations for most elements. Geographic d i s t r i -butions of s p h a l e r i t e 'enriched' i n minor elements c o r r e l a t e consistently with geographic d i s t r i b u t i o n s of Proterozoic and Lower Cambrian host rocks. Sphalerite 'depleted' i n minor elements occurs dominantly. i n Ordovician to Devonian host rocks. A si n g l e period of s p h a l e r i t e deposition i s inadequate to explain the observed minor element patterns. Two d i s t i n c t minor element populations c o r r e l a t i n g i n geographic d i s t r i b u t i o n with two separate age groups of host rocks indicate that at l e a s t two independant metallogenic events l e d to the s p h a l e r i t e m i n e r a l i z a t i o n . A major shale basin, l i k e l y dewatering to produce metal-rich brines, i s associated only with the Ordovician to Devonian hosts, whereas major uncon-formities and paleophysiographic elements suggestive of k a r s t i c environments are associated with the Proterozoic and Lower Cambrian hosts. A regional i n t e r p r e t a t i o n suggests that these d i f f e r e n t features might be responsible for the d i f f e r e n t minor element concentrations outlined. Therefore, a model of two metallogenic events, one during Middle to Late Cambrian, and another during Late Devonian or l a t e r , i s proposed to explain the s p a t i a l and temporal r e l a t i o n s between minor element populations and host age d i s t r i b u t i o n s of sp h a l e r i t e deposits i n carbonate rocks of the northern c o r d i l l e r a . i v TABLE OF CONTENTS PAGE ABSTRACT i i TABLE OF CONTENTS i v LIST OF FIGURES v i i LIST OF TABLES x LIST OF PLATES • x i i ACKNOWLEDGEMENTS x i i i CHAPTER 1 : INTRODUCTION 1 1.1 The Nature of Minor Element Studies and Their A p p l i c a b i l i t y 1 to the Northern Canadian C o r d i l l e r a 1.2 Review of Related Minor Element L i t e r a t u r e 3 1.3 Objectives and Outline of Present Study 9 CHAPTER 2 : MINOR ELEMENTS IN SPHALERITE 12 2.1 General P r i n c i p l e s of Minor Element Incorporation 12 2.2 ZnS Cr y s t a l Chemistry 14 2.3 Elements Recorded as Minor Constituents i n Sphalerite 22 2.3.1 Elements Most Commonly Recorded i n Sphalerite 23 2.3.2 Elements Less Commonly Recorded i n Sphalerite 28 CHAPTER 3 : THE SPHALERITE SAMPLE SUITE AND ITS MINOR ELEMENT ANALYSIS 31 3.1 Sphalerite Sample Suite D e s c r i p t i o n 31 3.2 Sample Preparation 32 3.3 A n a l y t i c a l Procedures 34 3.3.1 Emission Arc Spectroscopy 34 3.3.2 Atomic Absorption Spectroscopy 35 3.3.3 Mercury Analysis . 41 V 3.4 A n a l y t i c a l Results 46 3.5 A p p l i c a b i l i t y of Results 53 CHAPTER 4 : REGIONAL GEOLOGY OF THE NORTHERN YUKON AND ADJACENT 62 DISTRICT OF MACKENZIE 4..1 Introduction 62 4.2 Stratigraphy 64 4.3 S t r u c t u r a l Styles 77 4.4 Regional Synthesis: P o t e n t i a l f o r Strata-bound Zinc-Lead 80 M i n e r a l i z a t i o n CHAPTER 5 : MINOR ELEMENTS IN SPHALERITE FROM THE NORTHERN YUKON AND 85 ADJACENT DISTRICT OF MACKENZIE 5.1 Geological C h a r a c t e r i s t i c s of Sphalerite Occurrences i n the 85 Northern C o r d i l l e r a 5.2 Minor Element C h a r a c t e r i s t i c s of Sphalerite from the 97 Northern C o r d i l l e r a 5.3 Analysis of Minor Element D i s t r i b u t i o n s 101 5.3.1 Analysis of Variance 101 5.3.2 Inter-element C o r r e l a t i o n and Regression Analysis 105 5.3.3 Regional Geographic D i s t r i b u t i o n of Minor Elements 108 5.4 Comparison of Minor Element Contents i n Sphalerite from the 132 Northern C o r d i l l e r a with Other Areas and Types of :•[.!„. M i n e r a l i z a t i o n 5.5 Colouration i n Sphalerite from the Northern C o r d i l l e r a 136 CHAPTER 6 : INTERPRETATIONS, CONCLUSIONS, AND SUGGESTIONS FOR 144 FUTURE RESEARCH 6.1 Interpretations and Discussion: Implications for: ."' 144 Metallogenesis 6.2 Summary 153 6.3 Conclusions 154 6.4 Suggestions for Future Research 155 v i BIBLIOGRAPHY 157 APPENDIX A : GEOLOGIC AND MINERALOGIC DESCRIPTIONS OF INDIVIDUAL 166 DEPOSITS APPENDIX B : REGIONAL GEOLOGIC MAP AND CORRELATION CHART 203 APPENDIX C : CALCULATIONS OF ANALYTICAL PRECISION AND ANALYSES OF 206 VARIANCE C.l A n a l y t i c a l P r e c i s i o n 207 C.2 Analyses of Variance 209 APPENDIX D : APPLICATION OF PROBABILITY GRAPHS 228 v i i LIST OF FIGURES FIGURE PAGE 1- 1 MAJOR EXPLORATION CAMPS OF THE NORTHERN CORDILLERA 4 2- 1 CRYSTALLOGRAPHIC STRUCTURES OF SPHALERITE AND WURTZITE 16 2-2 ATOMIC PACKING AND COORDINATION IN SPHALERITE 17 2- 3 CHALCOPYRITE AND STANNITE STRUCTURES DERIVED FROM THE 19 SPHALERITE STRUCTURE 3- 1 COMPARISON OF ANALYTICAL RESULTS FOR SILVER, CADMIUM, 43 AND COBALT IN SPHALERITE 'STANDARDS' 3-2 COMPARISON OF ANALYTICAL RESULTS FOR COPPER AND 44 MANGANESE IN SPHALERITE 'STANDARDS' 3-3 COMPARISON OF ANALYTICAL RESULTS FOR IRON AND LEAD IN 45 SPHALERITE 'STANDARDS' 3- 4 VARIATIONS IN MINOR ELEMENT CONCENTRATIONS ACROSS A 53 ZONED SPHALERITE CRYSTAL AND IN TWO ADJACENT MASSIVE SPECIMENS 4- 1 PHYSIOGRAPHIC REGIONS OF THE NORTHERN CORDILLERA 63 4-2 REGIONAL GEOLOGY OF THE NORTHERN CORDILLERA 65 4-3 PALEO-PHYSIOGRAPHIC REGIONS OF THE NORTHERN CORDILLERA 66 4-4 DIAGRAMMATIC CROSS-SECTION, SELWYN BASIN TO MACKENZIE 68 MOUNTAINS 4-5 TIME-SPACE PROJECTION OF MACKENZIE MOUNTAINS, WERNECKE 69 MOUNTAINS, AND SELWYN BASIN STRATIGRAPHY 4- 6 TECTONIC ELEMENTS AND STRUCTURAL TRENDS OF THE NORTHERN 78 CORDILLERA 5- 1 INDEX MAP OF ZINC-LEAD DEPOSITS STUDIED 86 5-2 BAR GRAPHS SHOWING DISTRIBUTION OF DEPOSITS RELATIVE TO 91 AGES OF HOST ROCKS 5-3 GEOGRAPHIC DISTRIBUTION OF HOST ROCK AGE GROUPS 93 5-4 BAR GRAPHS SHOWING DISTRIBUTION OF DEPOSITS RELATIVE TO 94 HOST LITHOLOGY v i i i FIGURE PAGE 5-5 BAR GRAPHS SHOWING DISTRIBUTION OF DEPOSITS RELATIVE TO 95 MODE OF EMPLACEMENT OF MINERALIZATION 5-6 SCHEMATIC REPRESENTATION OF CORRELATIONS AMONG ELEMENTS 107 FOR 166 SAMPLE ANALYSES AND 48 DEPOSIT MEAN VALUES 5-7 SCHEMATIC REPRESENTATION OF CORRELATIONS AMONG ELEMENTS 107 FOR SPHALERITE TAKEN FROM PROTEROZOIC AND LOWER CAMBRIAN HOST ROCKS AND FROM ORDOVICIAN, SILURIAN, AND DEVONIAN HOST ROCKS 5-8 SCATTER DIAGRAM OF SILVER VERSUS MANGANESE 109 5-9 SCATTER DIAGRAM OF CADMIUM VERSUS MERCURY 110 5-10 SCATTER DIAGRAM OF IRON VERSUS MANGANESE 111 5-11 GEOGRAPHIC DISTRIBUTION OF SILVER IN SPHALERITE 114 5-12 GEOGRAPHIC DISTRIBUTION OF COBALT IN SPHALERITE 116 5-13 GEOGRAPHIC DISTRIBUTION OF COPPER IN SPHALERITE 118 5-14 GEOGRAPHIC DISTRIBUTION OF IRON IN SPHALERITE 120 5-15 GEOGRAPHIC DISTRIBUTION OF MERCURY IN SPHALERITE 122 5-16 GEOGRAPHIC DISTRIBUTION OF CADMIUM IN SPHALERITE 124 5-17 GEOGRAPHIC DISTRIBUTION OF 'COMBINED METALS' IN SPHALERITE 127 5-18 GEOGRAPHIC DISTRIBUTION OF ANTIMONY IN SPHALERITE 129 5-19 GEOGRAPHIC DISTRIBUTION OF CHROMIUM IN SPHALERITE 130 5-20 GEOGRAPHIC DISTRIBUTION OF TIN IN SPHALERITE 131 5-21 DISTRIBUTION OF SOME MINOR ELEMENTS RELATIVE TO COLOUR 137 IN SPHALERITE FROM BINNATAL SWITZERLAND 5-22 PLOT OF COLOUR VERSUS MEAN ANALYTICAL VALUE FOR FOUR 139 ELEMENTS 5- 23 PLOT OF MINOR ELEMENT CONTENT OF CO-EXISTING GREEN AND 142 ORANGE SPHALERITE GRAINS 6- 1 STRUCTURALLY CONTROLLED MIGRATION PATHS FOR DEWATERING 146 BASINAL SOLUTIONS i x FIGURE PAGE 6-2 DISTRIBUTION OF ORDOVICIAN TO DEVONIAN AGED HOST ROCKS 148 RELATIVE TO 'DEPLETED' POPULATIONS OF FOUR ELEMENTS 6-3 REGIONAL MINERALIZATION DUE TO TWO METALLOGENIC EVENTS 150 A - l CALIBRATION CURVE DEFINING DEVIATION IN TEMPERATURE 196 BETWEEN CONSOL READ OUT AND STAGE TEMPERATURE C-l SCHEMATIC DIAGRAM OF SAMPLE SEPARATIONS AND GROUPINGS 208 FOR PRECISION AND ANALYSIS OF VARIANCE CALCULATIONS C-2 TABULATION OF CALCULATIONS FOR AN ANALYSIS OF VARIANCE 210 D-1 PROBABILITY GRAPHS 230 X LIST OF TABLES TABLE PAGE 2-1 ELECTRONIC CONFIGURATION OF Zn AND S ATOMS 17 2-2 TETRAHEDRAL COVALENT RADII, AND IONIC CHARGE AND RADII, OF 20 SOME ELEMENTS COMMONLY FOUND SUBSTITUTING IN THE SPHALERITE STRUCTURE 2- 3 CHEMICAL COMPOSITION AND PRINCIPAL PHYSICAL PROPERTIES OF 21 THE MINERALS OF THE SPHALERITE AND WURTZITE GROUPS 3- 1 GEOGRAPHIC DISTRIBUTION OF SAMPLES AND SAMPLE LOCATIONS 32 3-2 EMISSION ARC SPECTROSCOPY DETECTION LIMITS 36 3-3 ATOMIC ABSORPTION SPECTROSCOPY OPERATING CONDITIONS AND 38 DETECTION LIMITS 3-4 PAIRED PRECISION TESTS 39 3-5 ATOMIC ABSORPTION ANALYSES OF 1 STANDARD'MATERIALS 42 3-6 EMISSION ARC SPECTROGRAPHIC ANALYTICAL RESULTS 47 3-7 ATOMIC ABSORPTION SPECTROSCOPIC ANALYTICAL RESULTS 50 3-8 CORRELATION OF ANALYTICAL METHODS 57 3-9 MINIMUM DEVIATIONS DISCERNIBLE ON ATOMIC ABSORPTION UNITS 59 3-10 INTERPRETATION OF ANOMALOUS DATA^ IN TERMS OF MINERALOGIC 61 DATA AVAILABLE 5-1 GEOGRAPHIC AND GEOLOGIC INFORMATION FOR 166 SPECIMENS 87 STUDIED 5-2 REGIONAL SUMMARY OF QUANTITATIVE ATOMIC ABSORPTION 98 SPECTROSCOPIC ANALYTICAL RESULTS 5-3 REGIONAL SUMMARY OF EMISSION SPECTROGRAPHIC ANALYTICAL 101 RESULTS 5-4 MEAN ATOMIC ABSORPTION ANALYTICAL RESULTS FOR 48 DEPOSITS . 104 5-5 CORRELATION MATRICES AMONGST EIGHT ELEMENTS FOR 166 106 SAMPLE-ANALYSES AND 48 DEPOSIT MEAN VALUES 5-6 POPULATIONS AND APPROXIMATE THRESHOLD VALUES DERIVED 112 FROM PROBABILITY PLOTS x i TABLE PAGE 5-7 TABULATION OF MEAN ANALYTICAL VALUES OF MINOR ELEMENTS IN 133 SPHALERITE FROM DIFFERENT LOCATIONS AND TYPES OF MINERALIZATION 5-8 MEAN ANALYTICAL RESULTS OF SOME ELEMENTS FOR FOUR COLOUR 140 GROUPS IN SPHALERITE A- l FLUID INCLUSION AND LAST MELTING HOMOGENIZATION DATA FOR 195 INCLUSIONS IN MINERALS ASSOCIATED WITH CARBONATE-HOSTED ZINC-LEAD DEPOSITS, Y.T. AND N.W.T. A-2 SULPHUR ISOTOPE ANALYSIS OF GALENA-SPHALERITE PAIRS FROM 197 CARBONATE-HOSTED ZINC-LEAD DEPOSITS, N.W.T. B-l SOURCES USED IN COMPILATION OF THE REGIONAL GEOLOGIC MAP 204 B-2 REGIONAL CORRELATION CHART 205 C-l SEVENTEEN TRIPLICATED SAMPLE ANALYSES 212 C-2 ANALYSIS OF VARIANCE OF TRIPLICATED SAMPLES 216 C-3 ANALYSIS OF VARIANCE: BETWEEN AND WITHIN DEPOSITS 220 C-4 ANALYSIS OF VARIANCE: BETWEEN AND WITHIN COLOUR CATEGORIES 224 x i i .LIST OF PLATES PLATE PAGE A - l BRECCIA TEXTURES 198 A-2 BRECCIA TEXTURES . 1 9 9 A-3 BRECCIA TEXTURES 200 A-4 VEIN TEXTURES 201 A-5 VUG AND CAVITY FILLING TEXTURES 202 x i i i ACKNOWLEDGEMENTS I am g r e a t l y indebted to Dr. C o l i n I. Godwin f o r conceiving t h i s research p r o j e c t and p r o v i d i n g f i n a n c i a l a s s i s t a n c e ; numerous ideas were generated i n e n t h u s i a s t i c d i s c u s s i o n s of t h i s p r o j e c t w i t h him and h i s encouragement and friendship are much appreciated. Dr. A. J . S i n c l a i r provided a s s i s t a n c e i n the s t a t i s t i c a l a n a l y s i s of the data and h i s support and c o n s t r u c t i v e c r i t i c i s m at a l l stages of the research i s acknowledged. Drs. R. L. Armstrong, J . A. McDonald, E. P. Meagher, and J . W. Murray a l l c r i t i c a l l y read parts of the manuscript. Considerable advice on a n a l y t i c a l methods and techniques was given by Mike and Ann Waskett-Myers. Computing problems were solved w i t h the help of Azger Bentzen. S p e c i a l thanks i s extended to Karen Medford f o r typing the f i n a l d r a f t of the t h e s i s . S p h a l e r i t e specimens from the northern c o r d i l l e r a were generously donated by numerous government and e x p l o r a t i o n company g e o l o g i s t s ; a l i s t of these c o n t r i b u t i n g sources f o l l o w s t h i s acknowledgement. F i n a n c i a l support f o r t h i s research from the Department of Indian A f f a i r s and Northern Development, from A r c t i c and A l p i n e Research, and from The U n i v e r s i t y of B r i t i s h Columbia i s g r a t e f u l l y acknowledged. x i v I n d i v i d u a l s and c o m p a n i e s t h a t p a r t i c i p a t e d i n t h e s p h a l e r i t e s t u d y o f c a r b o n a t e - h o s t e d z i n c - l e a d d e p o s i t s o f t h e Y u k o n T e r r i t o r y and a d j a c e n t D i s t r i c t o f M a c k e n z i e . Mr. R. Hewton R i o T i n t o C a n a d i a n E x p l o r a t i o n V a n c o u v e r , B.C. Dr. D. C r a i g D e p a r t m e n t o f I n d i a n A f f a i r s and N o r t h e r n R e s o u r c e s W h i t e h o r s e , Y.T. D r s . S. B l u s s o n and K. Dawson G e o l o g i c a l S u r v e y o f Canada Van co u v e r , B.C. Mr. M i k e M a c l n n e s G r e a t P l a i n s D e v e l o p m e n t Co. o f Canada L t d . C a l g a r y , A l b e r t a Mr. P e t e r T e g a r t Serem L t d . Van co uve r , B.C. Mr. Bob C a t h r o A r c h e r , C a t h r o , and A s s o c i a t e s W h i t e h o r s e , Y.T. Mr. B e r t Reeve B a r r i e r R e e f R e s o u r c e s L t d . V a n c o u v e r , B.C. G e t t y M i n e s L t d . V a n c o u v e r , B.C. Husdon Bay E x p l o r a t i o n and D e v e l o p m e n t Co. L t d . Van co uve r , B.C. Mr. Tony H i t c h i n s L t d . Amax E x p l o r a t i o n s , I n c . V a n c o u v e r , B.C. Mr. A r n i e B i r k e l a n d M c l n t y r e M i n e s L t d . V a n c o u v e r , B.C. Mr. J o h n B r o c k Welcome N o r t h M i n e s L t d . V a n o c u v e r , B.C. Mr. C o l i n V. Dyson UMEX B u r n a b y , B.C. Dr. Hugh M o r r i s Cominco L t d . Van co uve r , B.C. Mr. Len S a l e k e n L t d . W e s t e r n M i n e s L t d . V a n c o u v e r , " B . C . Mr. R.E. G o r d o n D a v i s C y p r u s A n v i l M i n i n g C o r p . V a n c o u v e r , B.C. N o r a n d a E x p l o r a t i o n L t d . W h i t e h o r s e , Y.T. T e x a s g u l f I n c . V a n c o u v e r , B.C. 1 CHAPTER 1: INTRODUCTION 1.1 The Nature of Minor Element Studies and t h e i r A p p l i c a b i l i t y to the Northern Canadian C o r d i l l e r a Sphalerite, being the most abundant sulphide mineral a f t e r p y r i t e , occurs i n a wide range of geologic environments, from low temperature hydrothermal deposits to much higher temperature veins and massive sulphide ore bodies, and hence, i t i s of s i g n i f i c a n t importance i n providing information on the conditions of ore formation. Detailed investigations into the geochemical a f f i l i a t i o n s of sphalerite, aimed at discerning i t s modes of p r e c i p i t a t i o n and i t s controls on, or c h a r a c t e r i s t i c s derived from, ore generation, aid i n developing genetic models and i n determining exploration c r i t e r i a f o r such deposits. Just as mineralogic r e l a t i o n s between minor and major constituents of an ore body can aid i n defining the physiochemical nature of ore solutions and of regional metallogeny, so the r e l a t i o n s between Zn and S, and the l e s s abundant non—stoichiometric elements that might be included i n sphalerite, provide information on the character of the p r e c i p i t a t i o n of i n d i v i d u a l grains or on the character of zinc deposits .within a region. Various elements can be included i n s p h a l e r i t e through isomorphous s o l i d s u b s t i t u t i o n and these are commonly present i n amounts of a few weight percent (such as cadmium or manganese) but might amount to 10 weight percent or more (such as i r o n ) . However, many other elements are c h a r a c t e r i s t i c a l l y present i n quantities ranging from barely detectable traces to a few hundreds of ppm. Due to the range i n factors c o n t r o l l i n g these v a r i a t i o n s i n concentration, a l l l e v e l s from 10 ppm to 10 weight percent might be of s i g n i f i c a n t value i n contributing knowledge to s p h a l e r i t e geochemistry, hence the term "minor" element i s applied as a more general d e s c r i p t i o n of concentration l e v e l s considered. "Minor" i s used i n preference to the term "trace", which i s f a r 2 more r e s t r i c t i v e i n use because i t r e f e r s only to very small q u a n t i t i e s . S p e c i f i c a l l y , "trace" would not include discussion of concentrations recorded i n the weight percentage ranges, even when these abnormally high values might be of p a r t i c u l a r s i g n i f i c a n c e . No precise c u t - o f f l e v e l i s implied i n a "minor" element study, and t h i s term i s more applicable i n t h i s t h e s i s . Investigations into the minor constituents of s p h a l e r i t e have been i n progress f o r many years, and t h i s provides a substantial background for t h i s study. Various authors have analyzed for d i f f e r e n t suites of minor elements and have reported t h e i r r e s u l t s with varying degrees of c e r t a i n t y . This i s i n part due to 1) the choice of a n a l y t i c a l methods a v a i l a b l e , 2) the elements of i n t e r e s t at the time, and 3) the a v a i l a b i l i t y of standard materials to compare a n a l y t i c a l accuracy with. Therefore the rare studies which defined the l i m i t a t i o n s of the analyses, the completeness of the minor constituent record, and t h e i r a n a l y t i c a l r e s u l t s compared to standards, are much more valuable, p a r t i c u l a r l y i f comparative data i s required. Nevertheless, these l i m i t a t i o n s do not imply that the conclusions drawn from minor element studies are i n v a l i d . For example, Stoiber (1940) drew the same conclusions that DeLaunay and Urbain (as quoted i n Stoiber, ibid.) recognized as early as 1912, namely that depth of v e i n formation (interpreted as a measure of temperature of formation) and that metallogenic provinces could be defined by the minor element contents of s p h a l e r i t e . Similar studies have been undertaken i n the c o r d i l l e r a of the United States o u t l i n i n g metallogenic provinces based on minor element content (Rose, 1970; Burnham, 1959), and i n the Canadian C o r d i l l e r a south of 60° l a t i t u d e (Evans et a l . , 1968; Warren and Thompson, 1945). Thus the analysis of s p h a l e r i t e appears to be a very u s e f u l t o o l i n preliminary i n v e s t i g a t i o n s of m i n e r a l i z a t i o n i n r e l a t i v e l y poorly known regions. A s p h a l e r i t e minor element study applied to the newly discovered carbon-ate hosted zinc-lead d i s t r i c t of the northern c o r d i l l e r a was designed to 3 define regional geochemical patterns i n t h i s r e l a t i v e l y unknown area. Exten-sive mineral exploration within t h i s region, encouraged by i n d i c a t i o n s of z i n c -lead p o t e n t i a l i n the northern Rocky Mountains of B r i t i s h Columbia i n 1970, dates only from 1972, yet i n the succeeding three years increasing i n t e r e s t led to the staking of some 18,000 claims i n the Mackenzie Mountains alone (Figure 1-1)(Brock, 1975) . Brock (1976) concluded that exploratory d r i l l i n g on some of the more promising showings indicated ore potentials of 10-20 m i l -l i o n tons of seven percent combined zinc and lead (e.g. Goz Creek, Bear, Gayna R i v e r ) . This i n t e r e s t and p o t e n t i a l promoted t h i s research into the d e s c r i p -t i v e regional metallogeny of the northern c o r d i l l e r a , with the intent of gaining i n s i g h t into genetic models r e l a t i n g stratigraphy, tectonics and m i n e r a l i z a t i o n . This thesis i s an evaluation of the minor element content of the sphalerites from t h i s region. The primary intent i s to broaden the knowledge of the geochemical nature of the sp h a l e r i t e i n 'ores' of the northern c o r d i l l e r a . The research project f i l l s a gap, by o u t l i n i n g the regional geochemical nature, as indicated by the minor elements i n sp h a l e r i t e , of the Canadian c o r d i l l e r a north of 60° l a t i t u d e . 1.2 Review of Related Minor Element L i t e r a t u r e Minor element studies have been u t i l i z e d best to determine v a r i a t i o n s i n the chemical character of c e r t a i n minerals r e l a t i v e to t h e i r genesis and to the region i n which they occur. More s p e c i f i c data regarding the geo-thermometry of p a r t i c u l a r deposits has been calculated using some minor elements but these studies tend to be highly r e s t r i c t e d i n a p p l i c a b i l i t y due to s p e c i f i c physiochemical c r i t e r i a which must be confirmed p r i o r to a p p l i -c a t i o n . Much work has been done on s p h a l e r i t e i n terms of i t s occurrence i n s p e c i f i c types of deposits (e.g. s t r a t a bound carbonate—hosted, vein, and 4 FIGURE 1-1 MAJOR EXPLORATION CAMPS OF THE NORTHERN CORDILLERA (aft e r Brock, 1975). Hatched area represents the regional extent of deposits examined i n t h i s t h e s i s . 5 kuroko types) and within s p e c i f i c metallogenic provinces (e.g. metal zones w i t h i n the North American c o r d i l l e r a , and various M i s s i s s i p p i V a l l e y mining d i s t r i c t s ) . Mercer (1976) recently summarized the pertinent l i t e r a t u r e regarding minor elements i n ores found i n sedimentary rocks. B r i e f l y , he describes s t r a t a bound carbonate—hosted deposits ( M i s s i s s i p p i Valley-type) as being generally d e f i c i e n t i n precious metals ( s i l v e r i s usually l e s s than 20 ppm, gold i s r a r e l y detected) and enriched i n cadmium and germanium. He notes the c h a r a c t e r i z a t i o n of various areas on the basis of s p e c i f i c minor element assemblages, most of which are discussed i n more d e t a i l below. Warren and Thompson (1945), i n one of the e a r l i e r regional studies, determined that western Canada, as a metallogenic province, produces sphal-e r i t e with c h a r a c t e r i s t i c a l l y high gold and t i n values and low gallium, germanium and vanadium values. Furthermore, they determined that many i n d i v i d u a l mining d i s t r i c t s within western Canada tend to exhibit character-i s t i c minor element assemblages. Hence they concluded that the o v e r a l l •, metallogenic province was established through regional a v a i l a b i l i t y of s p e c i f -i c elements and i n t e r n a l v a r i a t i o n s were developed by secondary controls of temperature and deposit type. In a more recent study of western Canadian carbonate—hosted lead-zinc deposits, Evans et a l . (1968) analyzed s p h a l e r i t e for i r o n , cadmium, manganese and selenium. D i s t r i b u t i o n of these minor elements were related to c r y s t a l -lographic parameters and were thought to r e f l e c t the temperature of formation of the deposits. Sulphur isotope r a t i o s , r e l a t e d paragenetic sequences and minor element composition data led to the development of a model for the o r i g i n of the deposits where "ore" metals were p r e c i p i t a t e d out of connate brines, i n a manner s i m i l a r to the proposal by Beales and Jackson (1966) . Jonasson and Sangster (1974), from the analysis only of the mercury 6 contents of s p h a l e r i t e from mines throughout Canada, confirmed the character-i s t i c v a r i a t i o n s of t h i s p a r t i c u l a r element wi t h i n metallogenic regions i n Canada, as well as with deposit type, host rock age, and to a l e s s e r extent, paragenetic a s s o c i a t i o n s . S p e c i f i c a l l y they stated that s p h a l e r i t e i n volcan-ogenic deposits contained more mercury than carbonate-hosted deposits, and that grouping of host rock ages r e f l e c t e d a decreasing abundance of mercury from Proterozoic to Phanerozoic to Archean age groups. They r e l a t e d v a r i a -tions with age to periods of increased mercury m o b i l i t y and deposition during tectonic disturbances; t h i s point, however, appears to require further i n v e s t i g a t i o n using a broader and more detai l e d data base. Sangster and L i b e r t y (1971) were able to d i s t i n g u i s h , on the basis of minor element contents, d i a g e n e t i c a l l y formed concretionary s p h a l e r i t e from non-concretionary s p h a l e r i t e associated with zinc—lead m i n e r a l i z a t i o n hosted wi t h i n the same carbonate formation i n the Bruce Peninsula, Ontario, Con-cretionary s p h a l e r i t e tended to be r i c h e r i n cadmium and i r o n and depleted i n lead, manganese and chromium r e l a t i v e to the non-concretionary s p h a l e r i t e . Copper, n i c k e l , and s i l v e r were non-diagnostic. This simple case i l l u s t r a t e s that mode of formation of the sp h a l e r i t e , even when s p a t i a l l y very c l o s e l y r e l a t e d , can be a s i g n i f i c a n t f a c t o r i n c o n t r o l l i n g the contents of minor elements. On a more regional scale, Burnham (1959) was able to characterize three d i s t i n c t metallogenic b e l t s of high trace element content, which are gener-a l l y consistent with the b e l t — l i k e d i s t r i b u t i o n of major ore deposits, i n southwestern U,S.A. and northern Mexico. Metallogenic b e l t s were defined on the basis of the geographic d i s t r i b u t i o n of (1) t i n , s i l v e r , and "combined metal content" i n chalcopyrite, and (2) the s l i v e r and "combined metal content"in s p h a l e r i t e . Provinces within each b e l t were distinguished on the basis that the elements characterizing the o v e r a l l b e l t s were not d i s t r i b u t e d evenly throughout i t . ' For example, a province of p a r t i c u l a r l y s i l v e r — 7 enriched s p h a l e r i t e was established and important s i l v e r - b e a r i n g minerals were found to occur within t h i s b e l t . Burnham indicated that h i s metallogenic b e l t s were r e l a t i v e l y coincident with the regional 'orogenic b e l t s ' described by B i l l i n g s l e y and Locke (1941) and concluded that the gross tectonic and metallogenic features were rel a t e d to fundamental deep seated compositional heterogeneities and associated physical d i s c o n t i n u i t i e s (Burnham, i b i d . , p. 70). Rose (1967, 1970) demonstrated that minor constituents of s p h a l e r i t e and chalcopyrite can characterize mining d i s t r i c t s i n the western U.S.A., as wel l as provinces w i t h i n each d i s t r i c t . C l a s s i c a l l y zoned hydrothermal depos-i t s w i t h i n these d i s t r i c t s gave r i s e to considerable small scale zonation i n i n d i v i d u a l s p h a l e r i t e c r y s t a l s , as w e l l as l a t e r a l and v e r t i c a l zonations about the deposit. This v a r i a b i l i t y , however, was i n s u f f i c i e n t to mask the apparent d i s t i n c t i o n s between d i s t r i c t s , although no s t a t i s t i c a l proof f o r thi s was given. Rose rel a t e d the o r i g i n s of the patterns to separate surges of ore f l u i d of pos s i b l e magmatic o r i g i n . Regardless of the genetic i n t e r -pretation, t h i s study further indicates the dominance of regional a v a i l a b i l i t y of elements over the f i n a l minor element content and demonstrates how metal-logenic provinces might be determined on th i s b a s i s . The d i s t r i b u t i o n of minor elements i n ore and host rocks of some M i s s i s s i p p i V a l l e y mining d i s t r i c t s has demonstrated (Hall and Heyl, 1968) that these constituents of s p h a l e r i t e and galena are d i s t i n c t within each d i s t r i c t . Furthermore, the r e l a t i v e proportions of some elements between these minerals can also characterize d i s t r i c t s . In one case, a l i m i t e d amount of data indicated a zonal arrangement of minor elements over a radius of 20 to 25 miles, centered on what was a probable feeder breccia f o r the ores. The authors concluded that the minor elements were leached along with the major elements from the source rocks ( i n t h i s case, basement rocks) v i a heated o i l f i e l d brines ( c f . Evans et a l . , 1968; and Doe and Delevaux, 1972). 8 E l Shazly et a l . (1957) studied a number of epigenetic and syngenetic samples of s p h a l e r i t e and galena from deposits i n the B r i t i s h I s l e s which exhibited a wide range of formation temperatures (as determined from geologic r e l a t i o n s and mineralogic assemblages) . Their findings confirmed the p r e v a l -ent opinion (of that time) that high temperature sphalerites were enriched i n indium, manganese, and t i n , and that low temperature s p h a l e r i t e s character-i s t i c a l l y contained gallium, germanium, and antimony. In those deposits s p a t i a l l y r e l a t e d to Intrusives, and therefore thought to be rel a t e d to hydro-thermal ( i . e . i n ferred higher temperature) controls, a zonation of minor elements was found. Syngenetic deposits contained r e l a t i v e l y low minor element contents and i n t h i s way resembled low temperature deposits. A comparison of s p a t i a l l y r e l a t e d s t r a t i f o r m and v e i n s p h a l e r i t e i n France by Halfon and Rosique (1973) produced somewhat d i f f e r e n t r e s u l t s , i n d i c a t i n g that v e i n samples of s p h a l e r i t e (again, i n f e r r e d higher temperature) contained more germanium, cobalt, copper, s i l v e r , and t i n , while the dispersed s t r a t i f o r m s p h a l e r i t e contained more barium, manganese, n i c k e l , vanadium, and chromium. A d i f f e r e n t spectrum of elements were determined i n t h i s study than by E l Shazly et a l . ( i b i d . ) hence they are not d i r e c t l y comparable. However, i t i s apparent that t h e i r conclusions c o n f l i c t with Halfon and Rosique on the degree of i n c l u s i o n of manganese and germanium i n sp h a l e r i t e r e l a t i v e to the temperature of formation, thereby suggesting other controls, such as regional a v a i l a b i l i t y , might be more s i g n i f i c a n t . Minor elements i n s p h a l e r i t e i n kuroko—type deposits of the Shakani Mine, Japan, were investigated by Nishiyama (1974) . Sphalerite i n t h i s environment tends to be enriched i n manganese, cadmium, gallium, and mercury r e l a t i v e to other ore minerals such as tennantite, galena, and ch a l c o p y r i t e . Iron contents i n s p h a l e r i t e were found to be r e l a t i v e l y low when compared to s p h a l e r i t e associated with other types of Japanese ore deposits. The d i s t r i b u t i o n of minor elements, p a r t i t i o n e d during c r y s t a l l i z a t i o n 9 between two co—existing host sulphides (e.g. cadmium i n s p h a l e r i t e and galena) has been used to determine temperatures of formation of ore deposits (Bethke and Barton, 1971; Maclntire, 1963). H a l l et a l . (1971) found t h i s method gave promising r e s u l t s f o r both manganese and cadmium d i s t r i b u t e d between s p h a l e r i t e and galena from the Darwin Mine, C a l i f o r n i a . Nash (1975) found, by applying t h i s technique to s p h a l e r i t e from the Mayflower Mine, Utah, that the best temp-erature estimates were 100°C higher than those obtained from f l u i d i n c l u s i o n homogenization temperatures. Only cogenetic sulphides can be used i n t h i s method and a n a l y t i c a l accuracy must be extremely high since the element of i n t e r e s t i s often present i n only trace quantities i n one of the minerals. Iron contents i n s p h a l e r i t e tend to increase with increasing temperature of formation and t h i s r e l a t i o n s h i p has been investigated as a u s e f u l geother— mometer for many years (Barton and Kullerud, 1958; Scott and Barnes, 1972) . This technique requires a precise knowledge of i r o n saturation and sulphur fugacity at the time of p r e c i p i t a t i o n of the mineral, hence i t s a p p l i c a t i o n was r e s t r i c t e d to equilibrium assemblages of p y r i t e , pyrhotite, and s p h a l e r i t e . More recent work (Craig and Scott, 1974) has shown that the mole percent FeS i n s p h a l e r i t e can vary appreciably at a given temperature or pressure, hence precise data on temperature of formation cannot be obtained. Furthermore, the experimental c a l i b r a t i o n data i s l a r g e l y extrapolated to lower tempera-tures (below 300°C) and phase r e l a t i o n s are very poorly defined f o r t h i s range. Therefore use of i r o n contents i n s p h a l e r i t e as an i n d i c a t o r of temperature of formation appears to have been i n v a l i d a t e d . 1.3 Objectives and Outline of Present Study D i s t r i b u t i o n s of minor elements i n s p h a l e r i t e , as discussed above, are of demonstrated use i n defining the o v e r a l l geochemical nature of a region 10 and any minor provinces within that region. Patterns recognized might develop i n response e i t h e r to the regional a v a i l a b i l i t y of elements or to more l o c a l i z e d geological factors (source or host rock composition, temperature of formation, tectonic h i s t o r y , metamorphic or i n t r u s i v e events, e t c . ) . The objectives of t h i s study, therefore, were to: 1) gather and analyze the minor element content of as many sp h a l e r i t e samples as p r a c t i c a l from a geochemically r e l a t i v e l y unknown broad area of the northern c o r d i l l e r a n carbonate b e l t , to define t h i s aspect of i t s geochemical nature, and to o u t l i n e metallogenic provinces within i t ; 2) determine a geological and genetic basis f o r any metallogenic provinces or trends found i n the regional d i s t r i b u t i o n of elements, and 3) compare these r e s u l t s with previously published data to determine the uniqueness of the northern c o r d i l l e r a n s p h a l e r i t e s . Presentation of these i n v e s t i g a t i o n s commences with a review of the nature of the occurrence of minor elements i n sph a l e r i t e i n Chapter 2. Discussed are: (1) general p r i n c i p l e s of minor element incorporation into a c r y s t a l l i n e substance, (2) the c r y s t a l chemistry of ZnS, and (3) a summary of possible substituents i n s p h a l e r i t e . Chapter 3 describes the c o l l e c t i o n of the sample s u i t e , i t s preparation and ana l y s i s , and along with r e s u l t s obtained, discusses the probable error sources i n the method and any l i m i t a t i o n s these introduce into the study. Chapter 4 describes the geology of the f i e l d area of i n t e r e s t together with a synthesis of features s p e c i f i c a l l y r e l a t e d to the formation of s t r a t a bound carbonate—hosted, zinc—lead deposits. Chapter 5 characterizes the nature of the sampled deposits of the region and of the s p h a l e r i t e samples themselves, p r i o r to presenting the i n t e r p r e t i v e techniques applied to the a n a l y t i c a l data and the r e s u l t i n g element d i s t r i b u t i o n patterns. The r e s u l t s are then compared with published data from other regions and deposit types. F i n a l l y a b r i e f statement i s made concerning the possible chemical agents that might be responsible f o r the colouration seen i n the specimens. An i n t e r p r e t a t i o n of the data presented i n t h i s t h e s i s , found i n 11 Chapter 6, i s followed by conclusions regarding the metallogeny of the north-ern c o r d i l l e r a . Suggestions for further research designed to substantiate the conclus ions of this paper are made as w e l l . A d e t a i l e d compilation of i n f o r -mation a v a i l a b l e on each deposit, a regional c o r r e l a t i o n chart and map r e f e r -ences, and a tabulation of s t a t i s t i c a l and graphical data manipulation tech-niques, are provided i n the Appendices. 12 CHAPTER 2: MINOR ELEMENTS IN SPHALERITE 2.1 General P r i n c i p l e s of Minor Element Incorporation Analysis and i n t e r p r e t a t i o n of the minor elements i n sp h a l e r i t e requires a knowledge of factors concerning the c r y s t a l chemistry of the host as i t re l a t e s to the s u b s t i t u t i o n of the minor elements. Atomic bonding character-i s t i c s are of prime importance i n predicting which elements might conceivably s u b s t i t u t e i n the s p h a l e r i t e structure. However, e l e c t r o n e g a t i v i t y , s t r u c -t u r a l co-ordination, complex ion formation and other factors w i l l a l l have ef f e c t s on the i n c l u s i o n of minor elements during c r y s t a l l i z a t i o n . These factors are considered below, i n i t i a l l y i n the l i g h t of the general p r i n c i p l e s governing incorporation of minor elements i n any mineral, and secondly, i n the s p e c i f i c case for sp h a l e r i t e . The s u b s t i t u t i o n of one element f o r another i s very common and i s accomplished i n a v a r i e t y of ways: 1. isomorphous s o l i d s u b s t i t u t i o n : s u b s t i t u t i o n of a ca t i o n or anion into a regular atomic p o s i t i o n , with only minor s t r u c t u r a l unit d i s r u p t i o n , and with a compensation for charge differences between the su b s t i t u t i n g and replaced ions, 2. i n t e r s t i t i a l s o l i d s u b s t i t u t i o n : acceptance of r e l a t i v e l y small ions or atoms into the i n t e r s t i c e s of a crystal,: ;with no replacement of host ions or atoms, 3. adsorption: the adherence of atoms or ions as t h i n films on a c r y s t a l surface or i n s t r u c t u r a l imperfections and d i s l o c a t i o n s (impurities can cause such d i s l o c a t i o n s ) , and 4. absorption: incorporation of f l u i d or s o l i d inclusions w i t h i n a growing c r y s t a l , often due to rapid growth around adsorbed impurities. Only s o l i d s o l u t i o n s u b s t i t u t i o n can be quantified according to c r y s t a l l a t t i c e parameters, hence much research into minor element contents has relat e d s o l i d s o l u t i o n s u b s t i t u t i o n to s p h a l e r i t e u n i t c e l l edge dimensions 13 (Grafenauer et a l , , 1969; Evans et a l . , 1968). Inclusion of adsorbed and absorbed material can be highly v a r i a b l e , r e s u l t i n g i n random chemical v a r i a t i o n s , c o n t r o l l e d i n part.by the a v a i l a b i l i t y of "contaminants". Such incl u s i o n s can, nevertheless, be s i g n i f i c a n t because they can r e f l e c t the bulk composition of sp h a l e r i t e forming s o l u t i o n s . Troshin and Troshina (1965) have attempted to indic a t e the s t a b i l i t y of ore f l u i d composition and physiochemical p r e c i p i t a t i o n parameters by ranking the mechanics of minor element incorporation according to the s t a b i l i t y of element concentrations. They propose that stable conditions are represented by s o l i d s o l u t i o n i n c l u s i o n , while e r r a t i c conditions lead to random absorp-t i o n . In this way they have attempted to explain v e r t i c a l zonation and minor element dispersion i n the ore deposits of the Severny Akatui region, U.S.S.R. Much of the basis f o r i n t e r p r e t i n g how and why minor elements s u b s t i t u t e into host l a t t i c e s was l a i d down i n three s i m p l i f i e d rules by Goldschmidt (1937). These can be paraphrased as: 1. atoms or ions with a radius w i t h i n 15%"*" of the substituted ion and with a s i m i l a r charge substitute f or each other r e a d i l y ; atoms or ions competing i n t h i s manner w i l l be admitted i n a proportion r e l a t i v e to t h e i r abundances; i n th i s way the minor element i s "camouflaged" by the major element, 2. atoms or ions with the proper charge but too large a radius f o r easy s u b s t i t u t i o n tend to be concentrated i n t o the l i q u i d phase, that i s , i n t o the l a t e r c r y s t a l l i z i n g f r a c t i o n s , and 3. when atoms or ions with s i m i l a r r a d i i , but d i f f e r e n t charges, compete f or a p o s i t i o n i n the structure, the element with the greater charge i s "captured" by the growing c r y s t a l s , that i s , concentrated i n the early f r a c t i o n s , while the element with the smaller charge i s "admitted" by the growing c r y s t a l s , or concentrated i n l a t e r f r a c t i o n s . These rules i n d i c a t e that s p e c i f i c elements might concentrate i n early or This tolerance may increase up to 25% under higher temperature conditions (Day, 1963). . 14 l a t e f r a c t i o n s of a s p e c i f i c mineral, hence, leading to the development of zonations with respect to time. They also show that s p e c i f i c elements may be suited to s p e c i f i c hosts and w i l l , as a r e s u l t , be found i n c h a r a c t e r i s t i c a l l y high quantities (such as i r o n and cadmium i n sphalerite) . However, these rules r e f l e c t an o r i g i n a l s i m p l i f i e d view on the nature of minor element s u b s t i t u t i o n , and i t eventually became apparent that excep-tions e x i s t e d . Most notable were the deviations developed i n the f i r s t set of t r a n s i t i o n elements, scandium to z i n c . For example, zinc was found to p r e f e r e n t i a l l y concentrate into sulphide minerals, or i f i n s i l i c a t e s , only into t e t r a h e d r a l l y co-ordinated atomic p o s i t i o n s , while Goldschmidt*s rules predicted a much wider range of s u b s t i t u t i o n (Burns, 1970). Therefore, other factors were found to account f o r the covalent nature of bonding i n some elements (numbers 1 to 3 below) and for the v a r i a b i l i t y i n concentration of some elements (numbers 4 and 5 below); these include ©'electronegativity (Ring-wood, 1955a), 2) co-ordination of the structure (Ringwood, 1955b), 3) bond energies (Burns, 1970), 4) a v a i l a b i l i t y and concentration of the substituent at the exact c r y s t a l l i z a t i o n s i t e (Sims and Barton, 1961), and 5) the physiochemistry of the c r y s t a l l i z i n g medium (pH, Eh, temperature, pressure, complex ion formation)(Sims and Barton, 1961). Factors 4 and 5 are d i f f i c u l t to specify for the time of c r y s t a l l i z a t i o n and th e i r e f f e c t s on the degree of minor element i n c l u s i o n are disputed, hence i t appears that the c r y s t a l chemistry of a host and i t s s u b s t i t u t i n g elements i s of prime importance (Burns, 1970). Therefore, a discussion of s p h a l e r i t e c r y s t a l chemistry and of the c h a r a c t e r i s t i c s of minor elements follows. 2.2 ZriS C r y s t a l Chemistry The most common cr y s t a l l o g r a p h i c form of zinc sulphide i s s p h a l e r i t e 15 (3-ZnS), however, other intimately r e l a t e d polymorphs e x i s t and are of i n t e r e s t due to t h e i r close, and u s u a l l y undetected, r e l a t i o n s h i p s to s p h a l e r i t e . The structure of g-ZnS i s face-centered, cubic, and close-packed (Figure 2-1) . The second major polymorph, wurtzite (a-ZnS), i s hexagonal and close-packed (Figure 2-1). The c r y s t a l l o g r a p h i c s i m i l a r i t i e s between these polymorphs can lead to an i n f i n i t e number of intermediate structures through s l i g h t l y d i f f e r e n t atomic stacking sequences; up to 150 ZnS polymorphs have been record-ed (Steinberger et a l . , 1973). Polymorph s t a b i l i t y i s apparently a function of temperature, as i t has been shown by Buck and Strock (1955) that as temp-erature increases the symmetry of ZnS decreases from the 4-fold cubic structure of s p h a l e r i t e through a 3-fold rhombohedral modification, to the hexagonal structure of wurtzite. Boyle and Jambor (1963) confirmed t h i s , demonstrating that B-ZnS i s stable over the temperature range of 600 to 1020°C. Above t h i s temperature, a-ZnS i s the stable polymorph 1. More recently Scott (1968) has indicated that the sphalerite-wurtzite phase t r a n s i t i o n i s also dependent on and wurtzite i s apparently sulphur d e f i c i e n t r e l a t i v e to s p h a l e r i t e . S t r u c t u r a l l y , the s p h a l e r i t e unit c e l l i s composed of Zn and S atoms,-each i n f o u r f o l d co-ordination, i n tetrahedra that are joined through t h e i r apices and rotated through 60° r e l a t i v e to one another. The r e s u l t i n g structure i s a face centered cubic arrangement (Figure 2-2), i s o s t r u c t u r a l with diamond and s i l i c o n carbide. The i o n i c model of s p h a l e r i t e , as determined from the e l e c t r o n i c configuration of the Zn^ + and S^ - ions (Table 2-1), reveals no free electrons or incompletely f i l l e d e l e ctron s h e l l s i n either ion, leading to the observed properties of poor e l e c t r o c o n d u c t i v i t y , transparency, and decreased r e f l e c t i v i t y (these properties change with increasing s u b s t i t u t i o n of foreign ions, notably Fe^ +, into the s t r u c t u r e ) . 1 a-ZnS i s stable at lower temperatures i n the presence of increased Fe content; i t appears stable to approximately 880°C with 17 weight percent Fe (Stanton, 1972). 16 (a) Sphalerite (b) Wurtzite FIGURE 2-1 CRYSTALLOGRAPHIC STRUCTURES OF- SPHALERITE (a) AND WURTZITE (b) The tetrahedral stacking sequences (A,B, etc.) lead to cubic symmetry i n sphalerite and hexagonal symmetry i n wurtzite. The c-axis of wurtzite i s a s i x f o l d screw axis involving a translation of one-half c for each 60° rotation of the tetrahedra. . (after Berry and Mason, 1959). Ideal cubic sphalerite i s o p t i c a l l y i s o t r o p i c , however increasing disorder from the perfect stacking sequences, due to str u c t u r a l translations or foreign substitution, leads to increasing anisotropic birefringence (Fleet, 1977). The covalent model of sphalerite shows complete saturation with hybrid bonds and the development of stable sp J hybrid o r b i t a l s (Griswold, 1968), henee the o v e r a l l bonding character i s e s s e n t i a l l y of a covalent nature with a few ionic t r a i t s . In the wurtzite structure, the atoms are i n fourfold coordination and the tetrahedra are linked through their apices, however, they are not rotated r e l a t i v e to their neighbours and the c-axis i s elongated r e l a t i v e to sphal-e r i t e producing a hexagonal close packed u n i t . Wurtzite may be preserved 17 a=5.406 A ' FIGURE 2-2 ATOMIC PACKING AND COORDINATION IN SPHALERITE (after Berry and Mason, 1959) metastably through rapid quenching after p r e c i p i t a t i o n or possibly at low temperatures under s p e c i f i c physiochemical conditions; Vaughan (1974) indicates that some M i s s i s s i p p i Valley-type sphalerites may actually have TABLE 2-1 ELECTRONIC CONFIGURATION OF Zn AND S ATOMS Element Zn S Atomic Number 30 16 Ionic Charge +2 -2 Electron . ^  Configuration [Ar], 4s 2, 3 d 1 0 [Ar] The [Ar] 'inert' core consists of completely f i l l e d I s , 2s, 2p, 3s, and 3p o r b i t a l s . 18 reverted from a wurtzite precurser. Wurtzite i s also found intimately i n t e r -grown with s p h a l e r i t e to produce 'schalenblende 1 which consists of al t e r n a t i n g layers of cubic and hexagonal layers (Stanton, 1972) . Atomic s u b s t i t u t i o n differences between s p h a l e r i t e and wurtzite appear to be uninvestigated, however, these are probably i n s i g n i f i c a n t since hexagonal ZnS and cubic ZnS maintain constant i o n i c charges, i o n i c r a d i i , and co-ordination numbers f o r the major elements. The s p h a l e r i t e structure w i l l t o l e r a t e s i g n i f i c a n t incorporation of 1 2 2 ir o n , cadmium , and manganese , In nature, most sphalerites are a c t u a l l y diadochic compounds of ZnS with FeS, MnS, and CdS. This i s to be expected as sphalerite i s i s o s t r u c t u r a l with at l e a s t one polymorph of MnS and CdS, and the covalent r a d i i of zinc, iron, manganese, and cadmium are s u f f i c i e n t l y s i m i l a r to encourage s u b s t i t u t i o n (Table 2-2). Less common members of the sp h a l e r i t e s t r u c t u r a l group (Table 2-3) include hawleyite (CdS), metacinnabar (HgS), tiemannite (HgSe), and coloradoite (HgTe) . A l l the elements present within these minerals are related; they occur i n si m i l a r columns of the periodic table and, hence, on a structure and charge b a s i s , they can become minor constituents i n s p h a l e r i t e . Some common minerals appear to be s t r u c t u r a l l y very s i m i l a r to sphalerite,, however due to d i f f e r e n t major elements f i l l i n g the l a t t i c e s i t e s , the true sphalerite structure i s s l i g h t l y deformed. These "defect d e r i v a t i v e s " include chalcopyrite, where the c-axis length i s doubled r e l a t i v e to that of sphaler^ i t e through alternate f i l l i n g of tetrahedral positions by copper and i r o n atoms, and stannite (C^FeSnS/j.), where the zinc l a t t i c e positions of the sphalerite model are occupied by copper, iron, or t i n (Figure 2-3). Bornite Iron contents are common up to 15 weight percent and have been reported up to 26 weight percent (Vaughan, 1976) . 2 Cadmium and manganese contents r a r e l y exceed 1 weight percent (Vaughan, i b i d . ) . 19 i s s t r u c t u r a l l y r e l a t e d to s p h a l e r i t e and chalcopyrite, but only 3/4 of the tetrahedral s i t e s i n the anion s u b l a t t i c e are f i l l e d i n b o r n i t e . FIGURE 2-3 CHALCOPYRITE AND ST ANNITE STRUCTURES DERIVED FROM THE SPHALERITE STRUCTURE (a f t e r Azaroff, 1960) Greenockite (CdS) i s i s o s t r u c t u r a l with wurtzite and d e r i v a t i v e members of t h i s group include cubanite (CuFe2S3) plus some ra r e r species (Table 2-3) . Any of the elements i n these minerals represent possible substituents i n the s p h a l e r i t e s t r u c t u r e . Elements able to enter structures s i m i l a r to that of s p h a l e r i t e , and 2+ 2-elements with i o n i c r a d i i s i m i l a r to that of Zn or S ions are most commonly found as minor constituents (Table 2-2). Generally charge balance considerations i n h i b i t s u b s t i t u t i o n of an ion whose charge d i f f e r s by more than one from that of the replaced ion, as other s u b s t i t u t i o n s must be made 2+ to compensate f o r t h i s d i f f e r e n c e . For example, Sn would be expected to 2+ undergo only l i m i t e d s u b s t i t u t i o n for Zn due to the s i z e d i f f e r e n c e s , and 4+ 2+ s i m i l a r l y Sn , even though of s i m i l a r radius to Zn , i s i n h i b i t e d from s u b s t i t u t i n g by a charge balance ( i n some cases a l i m i t e d s u b s t i t u t i o n of a 4+ 2+ s i n g l e Sn ion f o r two Zn ions might occur). Physiochemical factors c o n t r o l l i n g atomic su b s t i t u t i o n s are s u f f i c i e n t l y TABLE 2-2 TETRAHEDRAL COVALENT RADII, AND IONIC CHARGE AND RADII, OF SOME ELEMENTS COMMONLY FOUND SUBSTITUTING IN THE SPHALERITE STRUCTURE ( i n Angstroms)(after Azaroff, 1960; and F l e i s c h e r , 1955). 1.04 -2 1.84 Mn Fe 1.26 1.23 +2 0.80 +2 0.74 Co 1.32 +2 0.74 Ni 1.23 +2 0.69 Cu 1.35 +2 0.72 Zn 1.31 +2 0.74 Ga 1.26 +3 0.62 Ge 1.22 +2 0.73 As 1.18 +3 0.58 Se 1.14 -2 1.98 Ag 1.53 +2 0.89 Cd 1.48 +2 0.97 In 1.44 +3 0.81 Sn 1.40 +2 0.93 +4 0.71 Sb 1.36 +3. 0.76 Te 1.36 -2 2.21 o Hg Pb 1.48 1.46 +2 1.10 +2 1.20 +4 0.84 21 TABLE 2-3 CHEMICAL COMPOSITION AND PRINCIPAL PHYSICAL PROPERTIES OF THE MINERALS OF THE SPHALERITE (a) AND WURTZITE (b) GROUPS ( a f t e r Stanton, 1972) Cell dimen-Name Formula Crystal system sions, A Density Hardness Reflectivity " S i m p l e " m e m b e r s Sphalerite ZnS Cubic a = 5 .406 4 . 0 9 6 1 2 8 - 2 7 6 1 6 . 1 - 1 8 . 8 Hawleyite CdS Cubic a = 5 .818 4 . 8 7 ? ? Metacinnabar HgS Cubic a = 5 .854 7.65 7 3 - 8 6 26 .8 Tiemannite HgSe Cubic a = 6 .069 8 . 3 0 - 8 . 4 7 2 6 - 3 9 2 5 . 5 - 2 9 . 2 Coloradoite HgTe Cubic a = 6 . 4 4 4 8.04 2 3 - 2 8 3 6 . 2 - 3 7 . 7 " D e r i v a t i v e " m e m b e r s Chalcopyrite CuFeS. Tetragonal a = 5.28 c = 10.41 4 . 1 - 4 . 3 1 7 4 - 2 4 5 4 2 . 5 - 4 4 . 0 Stannite Cu_FeSnS 4 Tetragonal a = 5.46 c = 10 .725 4 . 3 - 4 . 5 1 7 1 - 3 0 7 2 7 . 1 - 2 8 . 0 Tetrahedrite- (Cu,Ag,Fe) 1 2 Sb 4 S 1 3 - Cubic a = 10.21 4 . 6 - 5 . 1 f 2 9 1 - 4 6 4 2 8 . 8 - 3 1 . 2 t tennantite (Cu,Ag,Fe) 1_As 4Si3 Famatinite Cu 3 SbS 4 Tetragonal a = 5.38 c = 10 .76 4 . 5 0 - 4 . 6 5 3 1 5 - 3 9 7 2 5 . 1 - 2 8 . 7 Enargite C u 3 A s S 4 Orthorhombic a = 6.41 b = 7 .42 c = 6 .15 4 .45 1 3 3 - 3 5 8 2 4 . 7 - 2 8 . 1 t Increases with increase in antimony and silver content, (a) S p h a l e r i t e group minerals Crystal Cell dimen-Name Formula system sions, A Density Hardness Reflectivity " S i m p l e " m e m b e r s Wurtzite ZnS Hexagonal a = 3 . 8 2 0 c = ' 6 . 2 6 0 4 . 0 8 9 1 4 6 - 2 7 4 1 7 . 4 - 1 8 . 2 Greenockite CdS Hexagonal a = 4 . 1 4 2 c = 6 . 7 2 4 4 . 9 5 2 - 9 1 19 .0 " D e r i v a t i v e " m e m b e r s Cubanite C u F e 2 S 3 Orthorhombic a = 6 .43 b = 1 1 . 0 4 c = 6 .19 4 . 0 3 - 4 . 1 8 1 5 0 - 2 6 0 3 9 . 2 - 4 2 . 5 Emplectite CuBiS 2 Orthorhombic a = 6 .13 b = 14.51 c = 3 .89 6.38 1 5 8 - 2 4 9 3 6 . 0 - 4 1 . 5 Chalcostibite CuSbS, Orthorhombic a = 6.01 b = 1 4 . 4 6 c = 3.78 4 .95 1 9 3 - 2 8 5 3 7 . 1 - 4 3 . 0 Sternbergite A g F e 2 S 3 Orthorhombic a = 6.61 b = 1 1 . 6 4 c = 1 2 . 6 7 4 . 1 0 1 - 4 . 2 1 5 4 0 - 7 4 3 2 . 0 - 4 0 . 0 (b) W u r t z i t e group minerals 22 v a r i a b l e that they are best examined i n accordance with the l o c a l geology and assumed conditions of formation. The general r e l a t i o n of increasing i r o n content, often complemented by increasing manganese content (Nash, 1975; Sims and Barton, 1961) with increasing temperature of formation has been documented (Barton and Kullerud, 1958; Sims and Barton, 1961) . However, the explanation of simultaneous independently varying concentrations of a number of elements i s d i f f i c u l t to e s t a b l i s h . For example, Taylor and Radke (1969), i n attempting to explain a unique s i l v e r - c h l o r i d e c o r r e l a t i o n with s p h a l e r i t e grains i n southeast Missouri, found no s i l v e r sulphide phases. They concluded from geochemical considerations that submicron grains of a complex chloride or an oxychloride phase were d i s t r i b u t e d through the s p h a l e r i t e . P a r i l o v et a l . (1973) concurred with t h i s conclusion from observations of specimens from c e n t r a l Kazakhstan, U.S.S.R.; they suggested that the s i l v e r h alides might form from s o l i d s o l u t i o n with s p h a l e r i t e or be included as submicroscopic i n c l u s i o n s . O v e r a l l , a number of fa c t o r s , often including 'contamination', are necessary to account f o r the v a r i a t i o n s i n minor element contents. 2,3 Elements Recorded As Minor Constituents In Sphalerite Factors c o n t r o l l i n g minor element i n c l u s i o n are s u f f i c i e n t l y v a r i a b l e that only generalizations regarding the probable nature of incorporation of a s p e c i f i c element ( i . e . isomorphous s o l i d s u b s t i t u t i o n versus 'contamination' from a for e i g n compound) or to the nature of the controls imposed by ore formation (e.g. temperature, metallogenic province) can be made here. The following discussion attempts to demonstrate 1) why a p a r t i c u l a r element might substitute into the s p h a l e r i t e structure, or 2) how i t might become included wi t h i n a sp h a l e r i t e sample. S p e c i f i c c h a r a c t e r i s t i c s determined for western Canadian sphalerites are Itemized, together with data r e l a t i n g to the a v a i l -23 a b i l i t y of s p e c i f i c elements i n the Mackenzie f o l d b e l t . 2.3.1 Elements Most Commonly Recorded i n Sphalerite Cadmium The tetrahedral covalent radius of cadmium i s close to that of zinc, therefore i t r e a d i l y substitutes into the s p h a l e r i t e structure. This suggests why cadmium i s c h a r a c t e r i s t i c a l l y present i n s p h a l e r i t e . According to F l e i s c h e r (1955) cadmium i s independent of the temperature of formation and of the paragenetic dep o s i t i o n a l sequence of s p h a l e r i t e . Cadmium concentrations thus must depend upon i t s a v a i l a b i l i t y i n ore forming s o l u t i o n s . Furthermore, no other mineral acts as a s i g n i f i c a n t host for minor concentrations of cadmium, and greenockite, the most common cadmium sulphide, i s r a r e l y reported from the Mackenzie f o l d b e l t . This r e l a t i v e l y rare element could be used as a geochem-i c a l pathfinder f o r s p h a l e r i t e i n exploration. Cobalt 2+ Due to a s i m i l a r i o n i c charge and s i z e as the Zn ion, cobalt i s r e a d i l y accepted into the s p h a l e r i t e structure and i s commonly found there. However, due to i t s s i d e r o p h i l e nature i t i s more commonly found i n the i r o n and copper sulphides, therefore cobalt may be p r e f e r e n t i a l l y included i n p y r i t e or chalco— p y r i t e rather than s p h a l e r i t e . The number of independent cobalt minerals' i s not large and a l l are uncommon i n the Mackenzie f o l d b e l t , however cobalt has been found associated with uranium and copper m i n e r a l i z a t i o n i n the Wernecke Mountains (Laznicka, 1977; B e l l , 1978) . Sims and Barton (1961) could f i n d no systematic r e l a t i o n between cobalt contents and the assumed temperature of formation of the s p h a l e r i t e samples. 24 Copper Copper i s strongly sulphophile and therefore concentrates i n many sulphides formed over a wide temperature range. I t i s r e a d i l y brought into s o l u t i o n i n the cupric state and i s u s u a l l y a v a i l a b l e i n ground or ocean waters i n low concentrations. O r i g i n a l l y copper was believed to be dominantly included i n s p h a l e r i t e as i n c l u s i o n s of chalcopyrite (Warren and Thompson, 1945; F l e i s c h e r , 1955), however cry s t a l l o g r a p h i c data i n d i c a t e zinc and copper to have a s i m i l a r i o n i c charge, radius, and a f f i n i t y f o r covalent bonding, hence i t w i l l r e a d i l y s u b s t i t u t e f o r zinc i n the s p h a l e r i t e s t r u c t u r e . Copper i s a commonly reported minor constituent i n most sp h a l e r i t e analyses and can amount to more than one weight percent (El Shazly et a l . , 1957). Gallium Gallium, r e l a t i v e l y rare in c r u s t a l abundance, appears to be concentrated i n s p h a l e r i t e . Strongly l i t h o p h i l e i n character, i t also enters into alumino-s i l i c a t e structures e a s i l y . Discrete minerals of gallium are rare, however compounds such as GaAs and GaSb are i s o s t r u c t u r a l with ZnS and Warren and Thompson (1945) proposed coupled substitutions of these compounds for ZnS i n s p h a l e r i t e . Day (1963) suggested possible l o c a l s o l i d s o l u t i o n of GaS or Ga2S3 with ZnS. Graesex: (1969) found gallium absent from s p h a l e r i t e assoc-ia t e d with a r s e n i c - r i c h sulphosalts; this might indi c a t e that gallium prefers a r s e n i c a l compounds i n preference to a s p h a l e r i t e host. Germanium Germanium i s a r e l a t i v e l y rare element and i t s concentration i n s p h a l e r i t e appears to depend on i t s a v a i l a b i l i t y w i t h i n a metallogenic province. Sulpho-p h i l e tendencies are indicated because a few germanium sulphide minerals are 2+ 2+ known. One of these permits interchange of Ge and Zn ions (germanite -25 Cu-jCGe, Ga, Fe, Zn) (As,S)4) (Roberts et a l . , 1974). In addition, i o n i c and covalent considerations i n d i c a t e that germanium can substitute into s p h a l e r i t e for z i n c . Indium Indium i s a common constituent of some sulphides, sulphosalts, and of c a s s i t e r i t e . Concentrations of up to 5,000 ppm indium i n sp h a l e r i t e have been reported, but the reason for th i s a s s o c i a t i o n i s obscure (Day, 1963). Indium i s generally concentrated i n deposits thought to form at medium to high temperature ranges (Fleischer, 1955; E l Shazly et a l . , 1957),, but due to i t s r e l a t i v e r a r i t y , regional a v a i l a b i l i t y i s apparently of importance. Iron Iron i s abundant (up to f i v e percent, Day 1963) i n the crust of the earth and e x h i b i t s a wide range of geochemical a f f i n i t i e s . It r e a d i l y substitutes into the sphalerite structure due to s i m i l a r i o n i c properties to zinc, and might be present i n abundance i n some samples. As a r e s u l t i t is sometimes not discussed as a 'minor' element. A general trend of i n c r e a s -ing degree of s u b s t i t u t i o n of i r o n f o r zinc i s noted with increasing temper-ature by various authors (Craig and Scott, 1974; Sims and Barton, 1961) and ir o n content has also been linked to colouration (the higher i r o n contents y i e l d i n g darker s p h a l e r i t e ) , however t h i s r e l a t i o n s h i p i s not exact (Roedder and Dwornik, 1968). Lead Lead.: i s generally ubiquitous i n the earth and i s found i n a wide v a r i e t y of compounds. I t e x i s t s e i t h e r i n a divalent of tetravalent state, however neither of these s u i t a b l y meets the Ionic requirements of s u b s t i t u t i o n i n the sphalerite structure. Sims and Barton (1961) have indicated that lead w i l l 26 s u b s t i t u t e f or zinc to a l i m i t e d degree 1. Lead minerals are commonly assoc-iated with ores of z i n c . Contamination of sphalerite with galena i n c l u s i o n s i s l i k e l y a prime source of lead i n many s p h a l e r i t e analyses. Manganese Manganese i s a common constituent i n most s p h a l e r i t e . This can be predicted by i o n i c considerations and by the crystallography of MnS and ZnS . Manganese, due to i t s geochemical s i m i l a r i t y to:'iron, tends to vary sympath-e t i c a l l y with i r o n contents i n sp h a l e r i t e , and hence also tends, i n general, to concentrate i n deposits thought to form at higher temperatures. Manganese and cadmium contents have been noted to vary d i r e c t l y with each other (Chakrabarti, 1967), and i n one instance, manganese has been d i r e c t l y r e l a t e d to colouration (Graeser, 1969) . Mercury Mercury can occur as atomic inclusions i n sph a l e r i t e (Watling, 1974), most l i k e l y due to i t s s i m i l a r covalent bonding character with z i n c . The large i o n i c radius, however, i n h i b i t s s u b s t i t u t i o n . Being a highly v o l a t i l e metal, mercury i s p a r t i c u l a r l y mobile under hydrothermal conditions and as a r e s u l t i t seems to be r e a d i l y transported into sedimentary rocks where i t s concentrations tend to be higher than i n igneous rocks (Day, 1963). J o l l y and Heyl (1968) determined that mercury was a common and widespread c o n s t i t -uent of sph a l e r i t e from zinc deposits of central and eastern United States and suggest that t h i s element may be of use i n prospecting f o r s i m i l a r zinc m i n e r a l i z a t i o n ( c . f . Ozerova, 1959). Occurrences of s t i b n i t e and cinnabar (HgS) have been found i n the Sims and Barton (ibid.) presumed that concentrations of up to a few hund-red ppm lead represents the approximate l i m i t of s o l i d s o l u t i o n of galena i n s phalerite at the temperature of formation of t h e i r samples. 27/ Mackenzie Mountain b e l t , and recently native mercury l o c a l i t i e s have been found (M_Arthur, M., 1911, pers. comm.) which i n d i c a t e that t h i s element might be a v a i l a b l e r e g i o n a l l y . N i c k e l N i c k e l appears to be a less common constituent of s p h a l e r i t e but i s quoted i n trace amounts i n some reports (Sangster and L i b e r t y , 1971; Nishiyama, 1974); often i t i s not determined. Covalent radius and charge s i m i l a r i t i e s with zinc suggest that n i c k e l may substitute i n t o s p h a l e r i t e , however i n c l u -sions of n i c k e l i f e r o u s p y r i t e and chalcopyrite have been suggested as a source of t h i s element i n analyses (Fleischer, 1955) . S i l v e r Most authors (Fleischer, 1955; E l Shazly et a l . , 1957) believe s i l v e r contents i n s p h a l e r i t e to be due to included i m p u r i t i e s . S l i g h t l y large i o n i c and covalent r a d i i of s i l v e r do not promote easy s u b s t i t u t i o n f o r z i n c . However, P a r i l o v et a l . (1973, p. 336) i n d i c a t e that luminesenee: spectra of s p h a l e r i t e "show that A g + enters d i r e c t l y into the mineral and also replaces + 3+ 3+ zinc, together with charge compensating elements: Ag with Ge or In and + 3+ Ag with TI ". They also suggest that argentian tetrahedrite-tennantite s o l i d s u b s t i t u t i o n with s p h a l e r i t e occurs due to s i m i l a r c r y s t a l s t r u c t u r e s . Ti n Higher concentrations of t i n i n s p h a l e r i t e tend to be found i n those medium to high temperature deposits (El Shazly, 1957) which also contain stannite or c a s s i t e r i t e . The l o c a l i z a t i o n of t i n deposits to s p e c i f i c small areas suggests that regional a v a i l a b i l i t y of t i n i s also important. F l e i s -cher (1955) has suggested that t i n can s u b s t i t u t e for zinc, despite i o n i c 28 s i z e and charge d i f f i c u l t i e s and s t r u c t u r a l s i m i l a r i t i e s between s p h a l e r i t e and stannite c r y s t a l s (Figure 2-3) enhances t h i s p o s s i b i l i t y . In western Canada, Warren and Thompson (1945) found that sphalerite containing t i n defines a metallogenic b e l t and i s more common than c a s s i t e r i t e . Preliminary explor-ation for t i n might therefore be guided by t i n analyses of s p h a l e r i t e . 2.3.2 Elements Less Commonly Recorded i n Sphalerite Ant imony Antimony i s r e l a t i v e l y rare i n c r u s t a l abundance, hence i t s d i s t r i b u t i o n might be co n t r o l l e d p r i m a r i l y by i t s a v a i l a b i l i t y w i t h i n a metallogenic prov-ince. I t i s chalcophile i n nature and tends to concentrate i n lower temper-ature deposits ( E l Shazly et a l . , 1957). Ionic charge differences i n h i b i t s u b s t i t u t i o n f o r zi n c , however, H a l l and Czamanske (1972) determined that copper and antimony might make coupled substitutions f o r zinc i n s p h a l e r i t e . Two common minerals of antimony, s t i b n i t e (Sb2S^) and jamesonite (Pb4FeSb6Sj4) can be found i n the Mackenzie f o l d b e l t and antimony was frequently found i n sphalerites of western Canada (Warren and Thompson, 1945), but always with inclusions of other minerals ( p a r t i c u l a r l y galena). Arsenic Arsenic tends to concentrate into sulphide ore bodies i n a wide range of minerals. I t tends to complex with other ions (such as gallium) to form u n i t s i s o s t r u c t u r a l with ZnS. In th i s way molecules bearing arsenic might substitute into s p h a l e r i t e . Bismuth Bismuth, analogous to antimony, i s rare i n c r u s t a l abundance and shows 29 a marked chalcophile nature. Its i o n i c character i s not s u f f i c i e n t l y s i m i l a r to that of zinc to make i t a s u i t a b l e substituent i n s p h a l e r i t e . I t i s reported i n sphalerites from western Canada but contamination of s p h a l e r i t e by other minerals, p a r t i c u l a r l y selenides and t e l l u r i d e s , i s l i k e l y (Warren and Thompson, 1945) . Chromium Chromium does not appear to be a l i k e l y candidate for i n c l u s i o n i n s p h a l e r i t e based on i o n i c charge and radius r e l a t i o n s ; the divalent state i s r a r e l y found. Due to the r e l a t i v e r a r i t y of chromium, regional a v a i l a b i l i t y i s l i k e l y of importance i n i n f l u e n c i n g i n c l u s i o n of chromium i n s p h a l e r i t e . Selenium L i t t l e data has been accumulated on selenium, mainly due to i t s r a r i t y ; i t u s ually i s absent or present only i n trace quantities i n s p h a l e r i t e . I t i s almost e x c l u s i v e l y chalcophile i n nature and occurs most often replacing sulphur i n minerals of heavy metals. I t may replace sulphur i n s p h a l e r i t e and i t might be important i n substitutions of molecular units (SbSe, HgSe) which are i s o s t r u c t u r a l with ZnS. Tellurium Tellurium i s r e l a t i v e l y rare and not often reported i n s p h a l e r i t e , however i t s a s s o c i a t i o n with selenium makes i t a possible substituent f o r sulphur. Warren and Thompson (1945) noted i t s a s s o c i a t i o n with bismuth i n s p h a l e r i t e from western Canada i n d i c a t i n g probable contamination by bismuth t e l l u r i d e minerals. 30 Vanadium Ionic rules suggest only a l i m i t e d amount of s u b s t i t u t i o n of vanadium for • zinc can occur. Warren and Thompson (1945) decided regional a v a i l a b i l i t y was the main factor i n determining the vanadium content of s p h a l e r i t e . This l i s t i s not considered to be complete i n describing a l l the elements found i n s p h a l e r i t e , however i t includes those elements commonly found, and those most useful i n characterizing s p e c i f i c deposits or b e l t s of deposits ( i . e . metallogenic b e l t s ) . A l l of the above elements have been used i n describing ore samples within a deposit or on a regional scale, and therefore have been'documented as p o t e n t i a l l y valuable i n d i c a t o r s . 31 CHAPTER 3: THE SPHALERITE SAMPLE SUITE AND ITS MINOR ELEMENT ANALYSIS 3.1 Sphalerite Sample Suite Description During the spring and summer of 1975, exploration companies involved i n zinc-lead exploration i n the Yukon T e r r i t o r y and the adjacent Northwest T e r r i t o r y were contacted by Dr. C o l i n I . Godwin, who requested samples from any carbonate-hosted showings located during t h e i r summer exploration a c t i v i t i e s . Any samples were accepted, however, coarse grained c r y s t a l l i n e s p h a l e r i t e was preferable, as samples s u i t a b l e f o r f l u i d i n c l u s i o n studies also were required. The purpose was to b u i l d a regional c o l l e c t i o n , from carbonate hosted sphalerite--galena showings, which could form the basis of a s e r i e s of ongoing research p r o j e c t s . The consequent c o l l e c t i o n forms a somewhat unique group of samples from approximately 100 separate l o c a t i o n s . Samples were taken e i t h e r by prospectors QT geologists involved i n 1) reconnaissance exploration, or 2) d e t a i l e d mapping and development ( i . e . trenches, diamond d r i l l cores, etc.) of the l a r g e r , more promising showings. Therefore, there i s a broad spectrum i n a c t u a l s p h a l e r i t e samples ranging from large boulders of e s s e n t i a l l y pure s p h a l e r i t e , through coarsely c r y s t a l l i n e and granular samples of s p h a l e r i t e , to s p h a l e r i t e which occurs only as very f i n e disseminations i n host rock. Sphalerite i s a minor sulphide component i n some showings which are dominantly galena, p y r i t e , or b a r i t e . Other sulphides observed i n some of the samples include chalcopyrite, t e t r a -hedrite, bournonite, and boulangerite. The host rocks are u s u a l l y dolomite or limestone, or breccias of these l i t h o l o g i e s , with sulphides i n a matrix of sparry c a l c i t e , dolomite, or coarsely c r y s t a l l i n e quartz, Most deposits, p a r t i c u l a r l y those with coarser grained s p h a l e r i t e specimens, produce clean 32 unaltered s p h a l e r i t e . Fine fractures through the s p h a l e r i t e generally contain t h i n coatings of carbonate contaminants and, i n a few cases, the s p h a l e r i t e has undergone a moderate to extreme degree of oxidation which commonly produced smithsonite. The s e l e c t i o n of a s u i t e of samples f o r minor element analysis was con t r o l l e d by the a b i l i t y to v i s i b l y separate any contaminants using a maximum 40X binocular microscope, In t h i s manner, a t o t a l of 166 samples from 48 locations were selected f o r a n a l y s i s . The broad geographic d i s t r i b u -t i o n of these samples i s given i n Table 3-1 and i n Figure 5-1, The number of samples per deposit i s normally low (from one to three) but i s as high as 20; at l e a s t nine deposits have a minimum of f i v e samples each. A l l but one are from carbonate hosted l o c a t i o n s . A d e t a i l e d d e s c r i p t i o n of each deposit i s given i n Appendix A. TABLE 3-1 GEOGRAPHIC DISTRIBUTION OF SAMPLES AND SAMPLE LOCATIONS T e r r i t o r y Number of Number of samples Ideations YUKON 82 24 N.W.T. 84 24 TOTALS 166 48 3.2 Sample Preparation Obtaining a pure s p h a l e r i t e concentrate was the most time consuming and the most important phase of the sample analysis i n t h i s minor element study. Due to the r e l a t i v e l y simple mineralogy of the samples i n general, v i s u a l separation of s p h a l e r i t e from contaminants by 'needle and tweezers 1 picking under a binocular microscope was thought to be the easiest and perhaps 33 quickest method. Magnetic separation and heavy l i q u i d concentration w i l l e f f e c t i v e l y remove most of the carbonate and quartz gangue materials, however separation of sulphide contaminants i s i n e f f e c t i v e , mainly due to contamina-t i o n by middling p a r t i c l e s . Picking under the binocular microscope would s t i l l be required i n the f i n a l stage ( c . f , P r i c e , 1972) but th i s i s impossibl on the small grain sizes required f o r e f f e c t i v e heavy media separation. Samples i n t h i s project were crushed and hand picked to apparent p u r i t y under 40X magnification. Finer grained s p h a l e r i t e samples, or s p h a l e r i t e containing fine-grained contaminations, were normally cut into 3-5 mm thick slabs which were found to disaggregate i n t o d i s c r e t e mineral grains more r e a d i l y , thereby f a c i l i t a t i n g hand p i c k i n g . At t h i s stage a number of sample were rejected on the basis of 1) possible contamination by excessive weather-ing, or 2) very f i n e g r a i n s i z e of intimately associated accessory sulphides. Fine-grained carbonate contaminants, inseparable under the microscope i n a few samples, were dissolved by soaking i n warm d i l u t e a c e t i c a c i d f o r several days. P u r i f i e d samples were ground to approximately -200 mesh i n an alumina-ceramic Spex b a l l m i l l , and were stored i n clean p l a s t i c v i a l s . Zonation i n colour and chemistry within s i n g l e s p h a l e r i t e c r y s t a l s i s common (Rose, 1967). These v a r i a t i o n s i n minor element content could not be studied using the separation procedure outlined, however, 17 samples were independently separated twice In order to check that hand picking y i e l d s r e s u l t s representative of the e n t i r e hand specimen. The s i g n i f i c a n c e of these v a r i a t i o n s and the a p p l i c a b i l i t y of the r e s u l t s w i l l be discussed subsequently. Throughout the separation process, notes on a l l samples were maintained on observed paragenetic associations, and, hence, on possible contaminants, i n order to a i d i n t e r p r e t a t i o n of anomalous values. Polished sections were studied to represent the micro^mineralogy of every deposit and these d e s c r i p -tions provided the basis f o r i n t e r p r e t i n g the v a l i d i t y of an a n a l y t i c a l 34 r e s u l t with respect to possible contaminating agents. A p p l i c a t i o n of these interpretations i s explained w i t h i n the following discussion of error sources. X-ray d i f f r a c t i o n of pulverized samples and point counting of polished grain mounts were used i n an attempt to quantify the degree of contamination by foreign minerals but the r e s u l t s were not prec i s e . 3.3 A n a l y t i c a l Procedures 3.3.1 Emission Arc Spectroscopy Emission arc spectroscopy i s a r e l a t i v e l y simple method to process large numbers of samples i n a q u a l i t a t i v e (or perhaps semi-quantitative) manner. Information about the range and magnitude of minor constituents i n the s p h a l e r i t e samples was gained r a p i d l y p r i o r to detailed atomic absorption a n a l y s i s . Arc spectroscopy used a H i l g e r Watts E-742 automatic quartz spectrograph. One hundred mg of the f i n e l y ground s p h a l e r i t e was weighed out on a t o r s i o n balance and stored i n a p l a s t i c v i a l . A further 100 mg. of carbon matrix material was added to provide a medium which would insure a constant and even burn. These volumes provided s u f f i c i e n t sample f o r three spec runs i f necessary. A f t e r these powders were mixed i n the v i a l s f o r one minute i n a Spex m i l l shaker, two glass beads were added and shaking continued f o r a further two minutes, providing a homogenous mixture of s p h a l e r i t e and graphite-.• Samples were then packed into cup-type carbon electrodes, and one drop of a sucrose s o l u t i o n was dropped on top of each to bind the sample and to a i d i n maintaining an even burn. The electrode holder was placed on a hot plate for one hour to dry. Samples were excited i n a 12 amp. D.C. arc for 30 seconds, with the 35 spectra being recorded on Kodak SA#1 glass photographic p l a t e s . Each p l a t e recorded ten samples plus one standard and one duplicated sample from another p l a t e . These plates were processed i n pai r s i n a Jarrel-Ash photoprocessor. Concentrations were estimated from these plates by v i s u a l comparison with standard plates with spectra ranging from one to 10,000 ppm, increasing i n approximately logarithmic steps ( i .e. 1,2,5,10,20,50,. . .10,000). Iron was determined as t o t a l i r o n oxide expressed as weight percent FeO. It should be pointed out that the sample values determined are q u a l i t a t i v e ; even th e i r r e l a t i v e magnitudes cannot be confirmed. This i s because the standard plates, which are the basis of the numerical determinations, were o r i g i n a l l y prepared using a g r a n i t i c rock matrix spiked with f o r e i g n elements. Matrix ef f e c t s were not investigated i n t h i s study, and consequently the numerical r e s u l t s are possibly inaccurate. A t o t a l of 20 elements of p o t e n t i a l i n t e r e s t could be determined using t h i s method"'". Detection l i m i t s f o r these are l i s t e d i n Table 3-2. Four elements, beryllium, bismuth, molybdenum, and platinum, were below detection l i m i t s . Analyses f o r 16 elements (antimony, arsenic, barium, cobalt, chrom-ium, copper, gallium, i r o n , manganese, n i c k e l , lead, s i l v e r , strontium, t i n , titanium, and vanadium) are l i s t e d i n section 3.4, Table 3-6. 3.3.2 Atomic Absorption Spectroscopy Atomic absorption spectroscopy, performed on solutions obtained from each sample, provided quantitative analyses. Sphalerite i s soluble i n an HCI-HNO3 s o l u t i o n , howeverj t h i s d igestion i n i t i a l l y presented problems. The s p h a l e r i t e i t s e l f was dissolved, but l i b e r a t e d sulphur, which remained "^  A 21st element of i n t e r e s t , indium, could have been determined using the standard plates, but t h i s element was used as an i n t e r n a l standard i n the graphite matrix material, hence, i t could not be recorded as a s p h a l e r i t e constituent. 36 TABLE 3-2 EMISSION ARC SPECTROSCOPY DETECTION LIMITS 1 Sb - 100 ppm As - 200 ppm Ba - 200 ppm Co - 2 ppm Cr - 1 ppm Cu - 1 ppm Ga - 1 ppm Mn - 1 ppm Ni - 2 ppm Pb - 1 ppm Ag - 1 ppm Sr - 100 ppm Sn - 1 ppm T i - 1 ppm V - 1 ppm Be - 2 ppm B i - 2 ppm Mo - 2 ppm Fe - 0.1 wt.% FeO Pt - no quantitative measure a v a i l a b l e - determinations purely q u a l i t a t i v e Detection l i m i t s are determined from lowest values detectable above instrumental i n t e r -ferences at minimum d i l u t i o n f a c t o r . undigested and coalesced into a yellow p l a s t i c b a l l . This sulphur was slowly decomposed using strongly oxidizing, conditions obtained by adding an excess of concentrated HNO3. Due to the range i n o v e r a l l sample s i z e s , some of which are as low as approximately 0.5 gm, an atomic absorption sample s i z e of 200 mg was chosen i n order to maintain a standard sample s i z e throughout, and to allow f o r d u p l i c a t i o n of an analysis i f necessary. This sample siz e kept the problem of ' p l a s t i c sulphur' d i s s o l u t i o n to a manageable l e v e l . A t o r s i o n balance was used to weigh out 200.00 mg of sample in t o a clean beaker. Ten ml of concentrated HC1 and 25 ml of concentrated HNO3 were added. The beakers were covered and l e f t on a warm hotplate for 18 to 24 hours u n t i l samples came slowly to dryness. They were then removed from the hotplate, taken up i n three ml of concentrated HC1, washed into a 25 ml volumetric f l a s k , and made up to the volume of the f l a s k . F i n a l solutions were then at an a c i d i t y of 1.5 M HC1, the l e v e l at which a l l samples, standards, and blanks were analyzed on the atomic absorption u n i t . Acid-cleaned poly b o t t l e s , used 37 f o r storage of sol u t i o n s , were rinsed with sample solutions p r i o r to storage. A complete set of 1:10 d i l u t i o n s was made by pipeting one ml of sample into a test tube, adding nine ml of 1.5 M HC1, and shaking stoppered tubes b r i e f l y , p r i o r to the spectroscopy. Further d i l u t i o n s of 1:10 ( i . e . t o t a l d i l u t i o n of 1:100) were made as required. Blanks were made by du p l i c a t i n g the acid attack using empty beakers. Secondary standard solutions were prepared from 100 ppm stock solutions and were aspirated before and a f t e r each group of samples run, A Varian-Techtron A.A.-4 u n i t was used to determine copper, i r o n and manganese. A Perkin Elmer model 303 u n i t , with background correction instrumentation, was used to determine silver„ cadmium, cobalt, n i c k e l and lead, s i m i l a r to procedures outlined by W.K. Fletcher (1970). Operating conditions and detection l i m i t s f or these eight elements are given i n Table 3-3. Samples were run i n groups of 24, each group consisting of 21 samples, two duplicates from d i f f e r e n t groups, and one blank s o l u t i o n . The 17 duplicates i s o l a t e d i n the separation procedure were treated as independent samples. Furthermore, the i n i t i a l sample of each of these duplicates was analyzed twice. In t h i s way the variance of d i f f e r e n t parts of the a n a l y t i c a l procedure could be s p e c i f i e d (see s e c t i o n 3.5). Computer calculated c a l i b r a t i o n curves provided conversion of a l l sample data from absorbance to concentrations i n ppm. Results are recorded i n section 3.4, Table 3-7. Three other elements, chromium, antimony, and titanium, were attempted since t h e i r presence was indicated by the emission spectrographic analyses. Antimony could not be accurately determined due to instrumental interferences obscuring both the standard and sample s o l u t i o n absorbance readings. Chromium and titanium concentrations were below detection l i m i t s and hence could not be determined ( s i m i l a r problems were encountered i n the n i c k e l and cobalt determinations). 38 . TABLE 3-3 ATOMIC ABSORPTION SPECTROSCOPY OPERATING CONDITIONS AND DETECTION LIMITS Element Wave.Length (A) Slit,Width (vim) Current .(mA) H.2 Lamp Detection Limits (ppm) 1 . a Ag 3280.7 1000 6 + 1 a Cd 2288 1000 6 + 50 a Co 2407.3 300 20 + 1 b Cu 3247.5 50 3 1 b Fe 2483 50 5 30 b Mn 2794 50 5 1 a Ni 2320 300 20 + 5 a Pb 2170 1000 14 + 4 ~^ Instrument used: a -- Perkin Elmer; b — Techtron 2 Detection l i m i t s are determined from lowest values detectable above instrumental interferences at minimum d i l u t i o n f a c t o r Calculations of 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 , based on duplicate sample analyses (Appendix C, Table C-l) were modified from the method of Garret (1969) and are summarized, with the formula used, i n Table 3-4. Samples were grouped according to concentration l e v e l s p r i o r to p r e c i s i o n c a l c u l a t i o n s to avoid u n r e a l l s t i c a l l y good p r e c i s i o n values at lower concen-tratio n s (due to i n c l u s i o n of higher concentration samples i n the o v e r a l l mean),. A n a l y t i c a l p r e c i s i o n i s reasonable (less than 25%) for s i l v e r , cadmium, manganese, and the intermediate and higher concentration l e v e l s of copper, i r o n , and lead. P r e c i s i o n i s poor f o r mercury and for the lower concentration l e v e l s of copper, i r o n , and lead. Cobalt and n i c k e l provided i n s u f f i c i e n t data for s t a t i s t i c a l a n a l y s i s . Differences i n p r e c i s i o n of combined hand sampling and a n a l y t i c a l procedures and of a n a l y t i c a l procedures alone ( i . e . a n a l y t i c a l set one versus 39 TABLE 3^4 PAIRED"PRECISION TESTS 1 ELEMENT GROUP MEAN VALUE RANGE NUMBER OF SAMPLE PAIRS IN GROUP PRECISION •(*•%) ANALYTICAL ANALYTICAL ' SET ill • SET 7/2 Cd Cu . Fe Mn Pb Hg A A A B C A B C A B 0-300 700-5000 0-50 90-370 500-800 0-800 -1500-2400 3300-13000 0-100 15-130 300-3450 0-225 17 17 6 8 3 8 4 5 17 8 9 13 13% 22% 92% 16% 63% 36% 10% 11% 21% 52% 17% 10% 11% 132% 3% 1% 43% 23% 10% 26% 30% 17% 72% P r e c i s i o n c a l c u l a t i o n s at the 95% confidence l e v e l followed the formula: , 1.98 a A , [ 7 N ~ P =? =: x 190% where • . 71 • . N2 r , X o A / 2^' z ' x l i ~ x 2 i duplicate samples V i = i and X , i s the r e p l i c a t e mean within the group, 40 a n a l y t i c a l set two ) are small and appear random (Table 3-4). Any v a r i a t i o n s provided by the picking of two samples from the same hand specimen appear to be i n s i g n i f i c a n t r e l a t i v e to the a n a l y t i c a l v a r i a t i o n s . Each an a l y s i s , there-fore, i s representative of the s p h a l e r i t e of an e n t i r e hand specimen ( i . e . the hand specimen i s homogeneous within the l i m i t s of a n a l y t i c a l p r e c i s i o n ) . A few samples do show s i g n i f i c a n t l y poorer p r e c i s i o n f o r the p a i r i n c l u d i n g both a n a l y t i c a l and sampling variances (e.g. lead at the lower concentration l e v e l s ) . Such l o c a l l y poor p r e c i s i o n was anticipated and i s l i k e l y due to the presence of fine-grained mineral contaminants. These contaminants w i l l presumably have a greater r e l a t i v e e f f e c t on the lower concentration ranges and p r e c i s i o n w i l l be poorer there. Poor p r e c i s i o n i n copper analyses can be a t t r i b u t e d dominantly to one or two samples (samples 20023-127 and 20024-7 (Table C-l) i n groups A and C r e s p e c t i v e l y ) , thereby further suggesting that i s o l a t e d cases of contamination do occur. A n a l y t i c a l p r e c i s i o n calculated without sample 20023-127 i s reduced from + 132% to + 15% f o r group A and combined a n a l y t i c a l and sampling p r e c i s i o n i s reduced from + 63% to + 3% f o r group C when calculated without sample 20024-7, This h i g h l i g h t s the f a c t that sporadic, h i g h l y anomalous samples do occur and might bias the i n t e r p r e t a t i o n of r e s u l t s . Interlaboratory standard s p h a l e r i t e was not a v a i l a b l e , making a true test 2 of the accuracy of the a n a l y t i c a l procedure d i f f i c u l t . However, 15 s p h a l e r i t e m i l l concentrates, presently being established as i n t e r n a l laboratory standards at the Geological Survey of Canada geochemical laboratories i n Ottawa, were made av a i l a b l e through Dr. I.R. Jonasson f o r an interlaboratory standard check on the a n a l y t i c a l procedure. When these powders were subjected A n a l y t i c a l set one represents duplicate samples segregated during the hand picking separation procedure; a n a l y t i c a l set two represents sample powders analyzed i n duplicate (see Appendix C, Figure C - l ) . 2 Flanagan (1974) indicates that a s p h a l e r i t e standard, SF-Y, has been synthesized i n Germany, but the nature of the s p h a l e r i t e and the a v a i l -a b i l i t y at present i s unknown. This source was discovered too l a t e to be investigated. 41 to the HC1-HN0- attack, a fin e white, granular residue was l e f t i n each sample, making i t necessary to f i l t e r a l l solutions p r i o r to being made UD to volume and a s p i r a t i n g on the atomic absorption u n i t . Otherwise these stan-dards were treated exactly as samples analyzed i n this study. The c o r r e l a t i o n between the established Geological Survey r e s u l t s and those obtained i n this study varies from element to element, and i n some cases, also varies from high to low concentrations for a given element. Table 3-5 l i s t s the r e s u l t s obtained and Figures 3-1, 2, and 3 graphically compare a n a l y t i c a l r e s u l t s of the two independent methods. Analyses of s i l v e r , cad-mium, cobalt (Figure 3-1) , and copper (Figure 3-2) obtained i n this study a l l tend to be s l i g h t l y lower than those of the Geological Survey, whereas manganese (Figure 3-2) tends to be s l i g h t l y higher. Lead and i r o n (Figure 3-3) show a considerable scat t e r of data points due to a greater disagreement of a n a l y t i c a l r e s u l t s . Owing to the d i s t i n c t l y d i f f e r e n t nature of the m i l l concentrate 'standard' materials, and the s p h a l e r i t e samples, coupled with d i f f e r e n t a n a l y t i c a l techniques (the p e r c h l o r i c acid, total-metal digestion procedure of the Geological Survey was not used i n this study), the number of background and complex-ion formation interferences i s expected to vary considerably between the two sample types. The e f f e c t s of these i n t e r f e r -ences, which would be p a r t i c u l a r l y evident at lower concentration l e v e l s , are not predictable. Therefore, these 'standards' do not serve as a true test of the a n a l y t i c a l method used i n this study. 3.3.3 Mercury Analysis A t o t a l of 160 samples, including 13 duplicates, were analyzed commer-c i a l l y f o r mercury by Min-En labs Ltd. of North Vancouver. The a n a l y t i c a l procedure used by this firm digests 1.000 gram of sample with n i t r i c and 42 TABLE "3-5 ATOMIC ABSORPTION ANALYSES OF 'STANDARD' MATERIALS Geological Survey r e s u l t s are i n brackets; O=below detection l i m i t s (refer to Table 3-3 f o r detection l i m i t s f o r each element); - =not determined; a l l re s u l t s i n ppm, except Fe reported i n wt,%. Sample Element number Ag Cd Co Cu Fe Mri ' N i Pb LCDF 7103 37 1004 139 3400 6.61 2336 0 1048 (40) (1148) (165) (4057) (7.30) (3000) (3) (1310) LCDF 7119 42 1032 85 3230 5.30 944 0 2632 (42) (1296) (106) (4453) (7.09) (830) (3) (3500) MTGM 7103 33 1131 50 2985 7.67 1314 0 936 (33) (1222) (51) (3373) (6.43) (1065) (3) (1138) MTGM 7123 35 1062 42 2620 7.30 1517 0 1248 (36) (1185) (50) (2864) (6.00) (1238) (3) (1552) MBRV 7111 400 1368 0 15555 2.43 50 0 9923 (264) (1593) (2) (13240) (2.30) (45) (5) (4655) MBRV 7133 359 1329 0 9877 1.79 37 0 788 (264) (1615) (3) • (10740) (2.08) (29) (5) (3167) NMTL 7004 35 1238 46 1950 8.34 184 0 445 (37) (1370) (54) (2356) (6.22) (150) (3) (500) NMTL 7009 33 1210 30 1700 5.21 198 0 493 (41) (1370) (35) (2237) (5.93) (174) (3) (500) NMTL 7129 39 1279 60 2850 6.41 123 0 439 (40) (1415) (69) (3373) (7.43) (99) (3) (500) ORCN 7104 32 717 56 1890 5.72 303 0 3205 (33) (800) (70) (2186) (6.26) (263) (3) (3667) ORCN 7128 24 771 65 2570 6.40 174 0 1756 (29) (903) (69) (3407) (5.44) (139) (3) (2176) STBY 7610 73 1816 52 3457 4.32 19 4689 (62) (2360) (40) (5250) (9.20) - (1) (1900) SLVN 7509 _ 6.70 41859 - - - - (11.30) - - (55000) SLVN 7602 _ _ 7.12 40159 - - - - (12.00) - - (56000) SLVN 7607 _ _ _ 6.91 46815 - . (11.30) - (62000) 4.3 10 2 3 4 5 6 7 8 9 100 2 3 4 5 6 7 8 9 1000 2 3 Results from this study (ppm) FIGURE 3-1: COMPARISON OF ANALYTICAL RESULTS FOR SILVER, CADMIUM, AND COBALT IN SPHALERITE 'STANDARDS'. S i l v e r i s represented by crosses, cadmium i s shown by closed dots, and cobalt i s denoted by open c i r c l e s . 44 FIGURE 3-2: COMPARISON OF ANALYTICAL RESULTS FOR COPPER AND MANGANESE IN SPHALERITE 'STANDARDS'. Copper (vlOO) i s represented by open c i r c l e s , and manganese i s shown by closed dots. 45 1 2 3 4 5 6 7 8 9 10 2 3 4 5 6 7 8 9 109 2 3 Results from this study (ppm) FIGURE 3-3: COMPARISON OF ANALYTICAL RESULTS FOR IRON AND LEAD IN SPHALERITE 'STANDARDS'. Lead (-M00) i s shown by open c i r c l e s , and i r o n ( i n %) Is denoted by closed dots. r 46 sulphuric acid. I t i s then further oxidized with 30% H_0. while heating; o x i d i z i n g steps are repeated as required. A f t e r cooling and d i l u t i n g to a Suitable volume to re f i n e the oxidation procedure, 5% KMnO^ i s added by t i t r a t i o n u n t i l the f i r s t pink colour i s obtained. Mercury i s analyzed i n the flameless atomic absorption chamber and measured by comparing samples with known standards ( J . J . Barakso, 1977, pers. comm.). P r e c i s i o n , based on the 13 duplicate samples, i s not p a r t i c u l a r l y good (±72%) . The a n a l y t i c a l r e s u l t s for mercury are included with the atomic absorption r e s u l t s i n se c t i o n 3.4, Table 3-7. 3.4 A n a l y t i c a l Results The a n a l y t i c a l r e s u l t s f or both the emission spectrographic technique and the atomic absorption techinque are tabulated i n this s ection i n order to keep this data together i n a p o s i t i o n for easy reference. Table 3-6 contains emission spectrographic data, and Table 3-7 contains atomic absorption and mercury analysis data. 47 TABLE 3-6 EMISSION ARC SPECTROGRAPHIC ANALYTICAL RESULTS (NO ANALYSES FOP. DEPOSITS 10020, 10032, 10050, r. 10053) 0 = MOT DETECTED: SEE TABLE 3-2 FOR OETECTICN LIMITS 10.NC. AG CD CU NI PB SB AS CR SR TI V RA GA SN FE 10006002 5 4 0 800 20 8 80 0 0 0 0 0 c 0 2 15 8;o 1CCC6003 15 r o 600 30 8 10 00 C . 0 0 0 0 0 0 2 15 s .o 1CC06CC5 8 3 5 100 70 10 30 0 0 5 0 5 0 0 2 3 3.0 10010C01 100 5 0 100 0 3000 C 2C0 0 02500 •••o 0 4 0 0 6.0 IC020004 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.0 1C022004 60 150 600 35 40 3000 "20 0 0 20 02500 30 0 40 0 6.0 10024001 15 50 50 35 5 6C0 IOC 0 0 0 5 0 0 1 8 3.0 10024002 15 0 1C00 40 C 500 0 0 0 0 10 0 0 25 35 1.0 10C25001 2 0 40 40 0 40 0 0 2 0 0 0 0 1 0 3.0 10025004 2 0 40 40 0 40 0 0 2 0 0 0 0 0 0 0.5 1C025C06 2 0 80 5 0 15 C 0 0 0 0 0 0 0 20 0.5 10C26001 70 • 70 750 35 60 10C0 0 0 0 0 30 0 0 35 0 5.0 1CC270C1 7 0 1100 10 0 50 0 0 3 0 10 0 0 15 0 0.3 1CC27CC2 2 0 900 8 0 15 0 0 0 0 10 0 0 20 5 1.0 10027003 50 0 1000 15 0 100 100 0 0 0 10 0 0 20 15 1.0 1CC27004 40 0 2CC0 30 C 8 00 200 0 0 100 15 0 0 50 30 5.0 10027005 30 0 600 15 0 150 100 0 0 0 3 0 0 30 35 1.0 1C028003 4 0 5 3 15 I CO • 0 0 0 0 5 0 0 0 0 1.0 1CC28007 8 0 0 2 0 50 0 0 2 0 0 0 6 8 0 0.2 10029002 . 2 0 15 8 0 1 00 C 0 0 0 1 0 0 0 0 1 .0 10C29CC4 15 0 30 15 50 700 100 0 0 0 1 0 0 1 0 3.0 1CC29CC5 40 0 40 10100 1 00 150 0 4 0 1 0 0 0 0 0.8 10C29003 0 0 50 10 50 300 c 0 0 0 5 0 0 I 0 1.0 1CC30C01 20 100 800 25 4C 90C0 0 500 8 100 20 8 0 0 0 5.0 10032001 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.0 10033001 15 o 700 8 0 100 130 0 0 0 100 0 150 0 0 0.5 100330C4 5 0 35 2 2 15 100 0 15 0 0 0 0 1 0 0.5 10033005 5 0 35 1 0 20 0 0 0 0 z 0 0 0 0 1.0 10033012 25 0 75 8 0 120 150 0 0 0 g 0 0 0 0 1.0 10033013 50 0 600 1 0 30 80 CO 0 0 0 0 0 15 0 1.0 10033014 100 0 25 ' 1 ' 0 15 0 0 2 • 0 ICO 0 0 0 0 2.0 1 0033015 2 0 0 3 c 2 00 C 0 0 0 2 0 0 0 3 1.0 10033016 5 0 . 0 5 0 1 50 150 0 0 0 5 0 0 1 0 0.5 10033017 15 0 400 1 0 50 18C 0 0 0 2 0 0 1 0 1.0 10033021 5 0 50 1 0 -30 80 0 0 0 1 0 0 0 0 1 .0 10033022 5 0 60 1 0 15 0 C 0 0 2 C 0 0 0 ,0.5 10033023 2 0 30 3 0 20 0 0 0 0 2 0 0 0 0 ' l . O 10033024 8 0 40 10 0 60 30 0 0 0 50 0 0 0 0 0.5 10033025 200 0 500 1 0 0 0 0 0 0 0. 0 0 0 0 1.0 10C34C01 1 0 10 20 c 100 0 0 0 0 0 0 0 0 0 2.0 10034002 1 8 20 15 0 75 c 0 3 0 5 0 0 0 0 2 .0 1CC34CC9 0 10 5 10 0 3 50 C 0 0 0 2 0 0 0 0 0 . 5 1CC35001 30 0 500 35 c 50 0 0 0 0 150 0 0 70 8 1 .0 10035002 15 0 500 35 0 35 C 0 8 0 150 0 0 40 8 0.8 1CC36C01 60 0 700 25 0 15 400 0 0 0 5 0 0 40 0 1.0 10036002 80 0 700 50 8 30 75 0 0 0 • 0 20 0 0 20 0 3 .0 10C37003 40 20 600 80 25 1 00 0 0 0 0 40 0 0 65 0 2.0 1CC370C4 50 30 600 30 25 150 0 0 3 0 750 0 0 30 0 4.0 10037020 100 180 700 4 0 20 130 150 0 0 180 20 C 0 85 20 3.0 1C037028 15 130 600 30 20 40 0 0 5 130 2 0 0 50 0 2.0 10037030 35 25 500 40 50 700 0 0 0 0 15 0 0 50 0 2 .0 1003 7031 40 15 700 60 20 150 0 0 0 0 20 0 0 50 0 .3.0 KCV37032 40 10 700 40 30 2 00 0 0 0 0 1 0 0 40 0 1 .5 10042001 15 0 700 4 0 0 100 80 0 0 0 5 0 0 50 4 I .0 KC42nC2 1 0 0 400 40 0 20 80 0 0 0 c c 0 50 0 0.5 10042003 10 0 2 00 ':0 4 50 0 0 0 0 5 0 0 40 10 1 .0 10042004 15 0 400 30 0 30 IOC 0 0 0 S 0 0 50 0 I .0 100420CP 25 0 600 10 0 75 200 0 0 0 2 0 0 50 100 0 . 5 10042009 25 0 300 50 0 150 150 0 0 0 0 0 0 20 8 50 0.5 1004 2010 05 0 150 15 0 300 0 0 0 0 3 0 0 5 1. 0 1C042C11 35 0 70 10 C 500 0 0 0 0 2 0 0 8 ? 1.0 10042015 20 0 300 5 0 80 0 0 0 0 1 c 0 8 0 1 .0 1CC42019 25 0 200 15 0 30 0 0 0 0 2 0 0 2 2 1 .0 1CC42023 I 8 0 100 10 0 10 0 0 0 0 1 0 0 8 2 3 .0 10042027 10 100 300 30 10 20 C 0 c 0 0 0 40 2 2.0 1004.2031 10 150 300 40 10 20 0 0 1 0 C 0 0 40 10 2.0 10C42036 50 0 300 40 0 2000 20 C 0 0 3 90 0 0 1 0 1.0 10042040 100 0 300 40 0 800 300 0 1 0 15 0 0 1 0 0. 5 10042041 80 0 4C0 50 c 1200 20C 0 0 0 40 0 0 I 0 2.0 1004 2042 15 0 100 20 0 15 0 0 0 0 0 0 0 2 0 2 .0 10042043 3 30 50 2 0 0 0 0 0 0 0 0 0 0 10 1.0 48 TABLE 3-6 (CONT INUED ) 10.N't. AG CO c u MN Ni PB SB AS CR SR TI V SA GA SN FE 1CC43CC4 5 0 30 2 0 80 0 0 0 0 30 0 0 15 0 1.5 10043005 3 0 40 1 0 60 0 0 2 0 15 0 0 25 0 0.8 10044001 4 0 900 20 0 100 . 0 0 0 0 20 0 0 0 0 1.0 10C45O01 8 0 80 5 40 120 0 0 2 0 10 . 0 0 0 0 1.0 10C46001 15 10 eoo 5 0 100 0 c 0 0 5 0 0 35 0 3.0 1OC46C02 50 0 700 40 0 1000 200 0 0 0 20 0 0 5 0 5.0 10C50C01 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.0 1CC53001 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.0 20C03004 0 0 40 10 0 10 0 0 0 0 2 0 0 10 0 5.0 20003005 4 0 500 2 0 700 0 0 2 750 0 0 0 20 10 0.0 20004001 0 0 0' 10 0 60 0 0 2 0 c 0 0 0 0 0.2 20004C02 3 0 ICO 6C 0 20 0 0 0 0 0 c 0 2 0 0.3 20004003 0 0 4000 15 0 20 0 0 0 0 20 0 0 75 5 1.3 200C5001 0 0 10 10 0 250 0 0 0 100 0 2 0 2 20 2.0 2CCC5CC4 7 0 200 25 c 4 00 0 0 0 0 0 0 0 8 0 5 .0 20006001 3 400 400 20 10 8 00 c 0 0 0 0 0 0 20 2 5.0 2C0C60C4 10 80 1500 15 30 100 0 0 2 150 300 1 0 40 8 4.0 2000600") 3 300 400 10 10 800 0 0 0 0 20 0 0 20 2 5.0 2C008007 0 0 15 10 0 1 50 c 0 0 0 10 c 0 2 0 0.5 200C8CCS 0 0 15 10 0 100 0' 0 0 0 0 2 0 2 0 0.5 20009004 8 0 15 25 0 500 0 0 0 0 0 0 0 0 0 0.5 20012001 0 0 30 10 0 15 0 0 0 0 c 0 0 2 5 0.0 20012002 10 0 50 30 0 25 c 0 0 0 0 0 0 5 0 0.0 20012003 0 0 70 20 0 15 c c 0 0 0 0' 0 8 5 0.0 20C12004 ' 5 0 200 20 0 100 10 0 0 3 0 80 0 0 0 0 0.3 20C12005 15 0 200 20 c 100 100 0 3 0 80 0 • 0 0 0 0.3 20012006 2 0 150 70 0 7 00 c 0 0 0 5 0 0 15 0 0.1 20C1 2007 15 0 300 40 0 1000 100 0 0 0 40 0 0 2 0 0.2 2001210? 10 0 150 30 0 6 00 150 0 0 0 30 0 0 2 0 0.5 20012010 15 0 150 30 0 3000 0 0 0 0 3C c 0 2 0 0.5 2CC120U 15 300 70 15 0 100 0 0 3 0 40 0 0 2 3 0.3 20012013 15 0 20 3 0 700 0 0 0 0 5 c 0 5 10 0.1 2CC13001 3 0 700 0 0 80 0 0 0 0 0 0 0 30 15 0.0 20015004 10 0 700 50 0 1 00 0 0 1 100 40 8 04 0 0 100 0.1 2C019004 5 0 40 10 c 40 0 0 0 100 20 01200 2 0 0.5 20C20CC3 5 0 60 20 0 40 c 0 0 0 70 0 0 10 0 2 .5 20021001 8 0 150 15 0 1 50 0 c 0 0 5 2 300 15 15 0.2 2CC21CC? P. 0 200 25 0 3 00 0 c 0 0 0 0 0 40 10 1.0 2CC23010 2 0 30 15 0 1 50 0 0 0 0 0 0 0 1 0 0.0 20023024 2 0 50 10 0 100 0 0 0 0 c 0 0 1 0 0.0 2CC23055 2 0 40 15 0 15 0 0 0 0 0 0 0 5 2 0. 1 20023060 3 0 30 30 0 70 0 0 0 100 0 0 300 1 0 0.1 20023061 5 0 30 40 10 40 0 0 5 0 0 c 0 1 0 0.2 2CC23CS6 2 0 30 30 0 120 0 0 0 0 0 0 0 I 0 0.0 20023C<37 Z 0 30 30 0 70 0 0 0 1 CO 0 0 0 2 0 0.1 20C23126 0 0 50 30 0 1 50 0 0 I 300 0 0 0 8 0 0.1 2CC23127 0 0 10 30 0 15 0 0 0 0 0 0 0 3 0 0 . 0 20023123 10 0 200 30 0 150 0 0 0 0 0 0 0 2 0 o . b 2CC2312-5 10 0 4CC 30 0 3 00 0 0 0 0 0 0 0 10 2 0.2 20023136 2 0 100 20 0 80 c 0 0 0 0 0 0 2 0 0.0 20C23138 5 0 200 10 0 1 50 0 0 0 100 c 0 0 5 0 0.0 2CC23140 5 c 200 30 c 150 0 0 0 800 0 0 60 0 8 0 0.0 20023141 3 0 40 '30 0 100 c 0 0 0 0 0 0 2 0 0.0 20023142 3 0 50 40 0 200 0 0 0 0 0 0 0 1 0 0.0 20C23144 5 0 100 50 0 500 0 0 0 100 0 0 0 8 0 0.0 20C2315? 10 0 40 50 G 800 0 c 0 0 c 0 p 2 0 0.0 20023154 3 0 40 15 0 300 c 0 0 0 0 0 0 0 0 OcO 20023155 10 0 150 30 0 150 0 0 0 200 0 0 200 10 0 0.1 20024001 60 0 150 25 0 100 0 0 0 0 0 a 0 8 0 1.0 200240C3 60 0 300 20 0 200 0 0 0 0 0 0 0 25 0 1 .0 20C24005 50 0 500 20 0 80' 0 0 0 0 0 0 0 50 8 0 .8 200240C7 15 0 700 40 0 15 0 0 0 0 5 c 0 50 10 0.0 20C240C8 20 0 500 5 0 0 0 0 3 0 50 01500 2 0 0.0 20024011 30 0 150 25 0 30 0 0 0 0 K 0 0 10 8 0.3 2CC25001 1 0 150 5 0 8 0 0 0 0 0 0 0 10 0 0. 3 20025002 0 0 200 1 0 0 0 0 0 0 0 0 6 3 5 0.0 20025003 2 0 200 8 0 15 0 0 0 0 5 c 0 15 0 1.0 2CC25CC5 . 0 0 100 10 0 2 0 0 1 0 0 0 0 0 0 1.5 20025006 1 0 200 10 0 30 0 0 0 0 8 0 0 5 5 1 .5 20C2501 0 0 0 100 5 0 5 c 0 0 0 50 0 0 2 0 1.0 20C25011 2 0 150 5 0 40 0 0 0 0 0 0 0 8 5 0.3 20025012 2 0 80 2 0 2 0 0 0 0 c 0 0 5 0 0 . 3 49 TABLE 3-6 I CONTINUED I 10.NO. AG CO CU MN NI PB SB AS CR SR TI V BA GA SN FE 2CC27CC3 0 90 30 30 3 400 0 0 0 0 2 0 0 3 5 0.8 20027004 A 0 70 15 0 3000 C 0 0 0 15 0 0 3 25 2.0 2CC32C01 100 0 1 30 0 400 0 0 0 0 C C 0 0 0 0.0 20 03'.001 0 0 700 15 0 15 0 0 0 0 30 0 0 40 20 3.5 2CC34002 0 0 50 10 3 25 0 0 0 0 C 0 5 3 2.0 2CC34003 0 0 60 10 0 30 0 0 0 0 0 0 0 7 0 4.0 20034005 3 0 200 3 5 7 0 0 I 0 C 0 0 2 3 2.5 2CC3401 1 2 0 200 3 0 20 0 0 0 0 0 c 0 3 3 2.0 20035001 15 c 1C00 20 0 10 0 0 0 0 0 0 0 80 5 0.0 20035002 15 0 5C0 4 0 4 CO C 0 3 0 1 0 0 4 0 0 0.3 20035003 0 0 600 20 0 8 C 0 0 0 0 0 0 35 30 0.0 2003 5006 3 0 600 15 0 15 0 0 0 0 0 C 0 2 0 1 .5 20C36001 0 40 30 5 5 2 C 0 1 0 3CC C 0 0 0 0. 9 2C036CC3 3 30 500 2 C 10 0 0 0 0 0 0 0 0 0 1.5 2C036005 0 0 503 30 0 15 0 0 1 0 40 0 0 25 3 2.0 2C036CC6 1 8 400 2 a 10 0 0 0 0 10 0 0 8 3 1.0 20037001 200 0 500 30 0 100 0 300 8 0 40 0 0 25 5 0.0 20037002 15 0 400 10 0 10 0 0 2 800 2C C 500 30 0 1.0 2CC38001 0 0 500 20 C 0 0 0 0 0 25 0 0 30 15 0.0 20039001 20 0 25 50 10 40 0 0 8 0 15C c 0 25 0 5.0 2CC40001 0 0 40 20 10 20 0 0 0 0 10 0 0 5 1 5 1.0 2CC40CC? 0 0 30 20 10 10 0 0 0 0 0 0 0 5 0 2.0 20040003 2 0 750 30 0 3 c 0 C 0 0 0 0 30 0 0.0 50 TABLE 3 - 7 ATOMIC ABSORPTION S PFCT ROGRAPHI C ANALYTICAL RESULTS 0 = NOT DETECTED: SEE TA3LF 3-3 POP. DETECTION LIMITS N . O . = NOT DETERMINED 10.NO. AG CD CO CU FE MN NI PR HG 1000600? 4. 7 . 878 12.6 123 13840 26 0.0 217 3 .00 10006003 13.2 1010 15. 1 95 1 32 80 26 0.0 3462 0 .00 1 0 r 0 6 0 0 5 3.4 975 10.5 6 I 10130 71 0.0 55 2 .50 10010001 59. 4 1110 0.0 10 1 20 165 0.0 1350 ' 0 .02 1 0 0 2 0 0 0 4 32.3 1460 5.4 394 63 13 230 0.0 477 N . 0 . 10C22004 35. 6 706 22. 1 172 91 80 32 0.0 371 1 12 .50 10024001 10.5 1548 9. 7 26 4976 14 0.0 870 0 .00 1002400? 11.4 1993 0.0 229 1857 34 0.0 987 215 .00 10025001 2. 5 1 795 0.0 1 5 3642 26 0.0 98 1 44 .00 10025004 2.6 1688 0.0 67 2004 5 0. 0 83 10 .50 10025006 3.0 1740 0.0 56 1530 4 0.0 0 12 .50 10C26001 45. 1 1425 8.4 412 6812 47 0.0 1279 8 .00 10027001 4. 1 1584 0. 0 164 1311 13 0.0 451 1 92 .50 10027002 6. 6 2065 0. 0 140 7 49 1 1 0.0 132 0 .00 10027003 22. 6 2123 0.0 157 12 45 13 0.0 594 295 .00 10027004 15. 7 2359 0. 0 222 20 76 16 0.0 266 295 .00 1C0270C5 19. 9 2274 0. 0 209 2363 1 1 0.0 710 2 92 .50 10023003 1. 8 3445 0.0 1 3 1712 0 0.0 • 255 7 .50 10028CC7 2.8 4200 0.0 1 0 496 0 0.0 91 2 .20 1 0 0 2 ° 0 0 2 2. 1 1135 0.0 1 3 2477 4 0.0 350 N . 0 . 13C29004 10.9 2 922 0. 0 13 4554 7 9.5 131 4 2 . on 19C29005 16. 7 2S6? 0. 0 2 1 1821 4 16.4 203 0 . 11 10029008 0. 0 2117 0.0 24 18 34 3 0. 0 570 0 .05 1013 0001 45. 5 172 27.9 513 1 21 40 75 12.0 10750 60 .00 1003 2001 6. 3 1 100 97. 9 92 35670 33 0.0 33 79 N . D . 10033001 6.3 1629 0. 0 99 11 59 2 0.0 218 52 .50 10033004 2.6 1529 0.0 1 3 11 59 0 0.0 61 26 . 50 10033005 2.3 122 6 0. 0 21 9 86 0 0.0 42 26 .50 1003 3012 23. 9 1943 0.0 4 1 17 75 8 0.0 839 1 20 . 50 10033013 90. 3 1680 0.0 343 18 48 2 0.0 14? 267 .00 10033014 295. 9 2401 0. 0 13 1701 0 0.0 29 0 .00 10 03 301 5 0. 0 1222 0.0 3 I 1069 2 0.0 467 40 .00 10033016 2. 9 12 02 0. 0 13 1087 5 0.0 640 40 .00 10033017 16. 0 1612 0.0 123 1322 2 0.0 136 1 48 .00 10033021 2.6 1460 0.0 , ?6 1083 0 0.0 68 46 .50 10033022 4. 7 1234 0. 0 37 1087 3 0.0 38 63 .50 10033023 3. 6 1515 0. 0 13 1159 2 0.0 73 44 .50 10033024 0. 0 1570 0. 0 21 1123 3 0.0 96 38 .50 10033025 155. 3 1622 0 . 0 160 1304 C 0.0 0 1 54 .00 10034001 0. 0 9.30 0.0 31 2500 1 3 0. 0 229 10 .50 1003400? 0. 0 930 0. 0 13 2645 6 0.0 165 4 .00 10034009 0.0 719 7.3 8 1304 6 0.0 1587 2 .CO 10C35001 15.2 2224 0. 0 356 2500 32 0.0 110 3 .50 1003500? 14. 3 2495 0. 0 299 21 93 57 0.0 P7 3 .00 10036001 27.4 1200 0 .0 571 1739 11 0.0 23 8? . 50 1003600? 28. ? 1C64 0.0 563 3260 18 0.0 50 0 .00 10037003 11.7 2105 0.0 145 23 7 3 10 3 C O 177 12 .00 10 0 370 04 37. 6 1140 0.0 389 66 54 16 0.0 3?6 5 .00 10037020 32. 7 2299 13.6 33 7 3781 25 0.0 180 N .CV. 10037028 15.8 1733 13.6 213 52 55 46 0.0 95 8 .80 10037030 40. 3 2613 6.5 555 4234 74 0.0 2307 3 .50 10037031 43. 0 2375 5.4 52 4 50 28 103 0.0 621 7 .50 1C037032 40. 3 2835 0.0 50 1 55 58 146 9.4 853 8 .80 1CC42001 15. 2 1599 0.0 23 0 23 19 58 0.0 347 0 .00 1C042C02 7. 1 1815 0.0 335 1390 51 0. 0 113 45 .50 10042003 5. 1 1448 0.0 171 2268 3 6 0.0 197 67 .50 10042004 9. 4 1668 0.0 356 13 90 49 0.0 95 N . 0 . 10042008 40. 3 1439 0.0 535 1928 10 0.0 327 1 03 .50 10C47009 35. 6 1318 0. 0 271 2149 10? 0.0 659 0 .00 10042010 34.3 1439 0. 0 73 36 29 26 0.0 1601 1 24 .50 100420U 24.2 1470 0.0 62 34 73 29 0.0 700 117 .70 10042015 13. 8 1630 0. 0 1 6 9 2268 3 0.0 353 1 35 .50 10042019 13. 2 1605 0.0 31 27 60 14 0.0 99 1 63 .00 10042023 4.5 1 069 25.2 210 6573 33 0.0 44 71 .00 10042027 14. 8 1474 0.0 48 7311 16 0.0 36 8 .00 1004 2031 4.4 1048 26.0 214 53 21 51 0.0 21 7 . 50 10042036 56. 6 2388 0.0 219 3062 116 0.0 4975 66 .50 10042040 82.8 2827 0. 0 31 7 2220 73 0.0 1307 61 .00 10042041 41.2 2355 0.0 183 2794 99 0.0 3049 53 .50 10042042 13. 7 1231 0. 0 45 3292 28 0.0 24 1 08 .50 10042043 2.1 1394 5.4 45 2488 5 0.0 15 62 .50 51 T A B L E 3 - 7 { C O N T I N U E D ) i n . N O . AG ' C D C O cu F E MN N I P 8 H G l f ! C 4 3 0 0 4 0 . 0 1 2 6 1 0 . 0 1 1 2 6 0 3 0 0 . 0 1 8 3 2 . 0 0 10943005 0 . 0 1 6 2 4 0 . 0 1 6 1 8 3 7 3 0 . 0 1 1 6 0 . 2 2 1 0 0 4 4 0 0 1 4. 9 1 7 6 0 0 . 0 7 2 2 49 5 4 2 2 0 . 0 3 C 9 0 . 0 0 1 0 C 4 5 0 0 1 5 . 2 2 6 7 6 0 . C 2 9 2 5 2 6 3 0 . 0 2 3 5 0 . 8 1 I O C 6 0 0 1 6 . 8 1 4 6 5 0 . 0 56 0 3433 3 0 . 0 8 7 1 7 . 5 0 I C C 4 6 C 0 2 2 2 . 9 1 8 2 9 0 . 0 6 7 9 5 3 9 5 2 9 0 . 0 1 0 5 5 41 . 0 0 1 0 C 5 0 0 0 I 0 . 0 6 9 3 0 . 0 4 0 1 0 1 1 1 5 0 . 0 4 7 3 M . n. 1 0 C 5 3 0 0 1 4 . 3 1 7 9 5 0 . 0 5 8 5 9 8 0 . 0 37 N. D . 2 0 C 0 3 0 0 4 0 . 0 1 4 2 7 0 . 0 6 0 1 43 4 0 1 0 0 . 0 2 8 2 . 5 0 2 0 0 0 3 0 0 5 3 . 5 2 3 3 4 0 . 0 9 6 4 0 1 2 0 . 0 1 2 3 0 4 4 . 0 0 2 0 C 0 < . 0 0 1 0 . 0 1 1 3 8 0 . 0 8 7 2 0 1 5 0 . 0 2 6 3 0 . 3 6 2 0 C C 4 0 0 2 0 . 0 1 9 3 3 C . 0 6 8 6 3 5 8 7 0 . 0 39 18 . 0 0 2 0 0 0 4 0 0 3 0 . 0 1 2 0 1 0 . 0 2 1 8 3 6 1 9 1 0 0 . 0 4 1 N . 0 . 2 0 C 0 5 0 0 1 0 . 0 4 4 6 6 0 . 0 1 0 1 8 6 3 8 0 . 0 4 8 1 N . n. 2 0 C 0 5 0 0 4 3 . 7 4 5 8 6 0 . 0 1 1 0 41 74 2 4 0 . 0 8 7 0 0 . 0 0 2 0 0 0 6 0 0 1 2 . 6 1 0 3 0 6 6 . 9 2 2 1 6 6 3 0 9 0 . 0 2 1 1 4 6 . 20 2 C C C 6 0 0 4 5 . 2 1 5 9 4 7 . 0 1 6 6 3 5 9 3 5 1 3 0 . 0 1 4 8 6 . 5 0 2 0 0 0 6 0 0 5 2 . 6 1 1 9 3 6 4 . 0 434 78 93 1 0 0 . 0 2 1 1 4 4 . 9 0 2 0 0 0 . 3 0 0 7 0 . 0 7 5 5 0 . 0 8 1 2 9 4 9 0 . 0 4 5 0 M. D . 2 0 C 0 8 C C 9 0 . 0 7 6 7 0 . 0 8 1 5 9 0 1 8 0 . 0 3 3 6 0 . 0 0 2 0 0 0 9 0 0 4 0 . 0 2 3 9 8 0 . 0 1 0 1 3 2 6 2 1 0 . 0 1 8 3 1 0 . 4 9 2 0 01 2 0 0 1 0 . 0 1 4 5 0 0 . 0 3 6 1 2 0 1 7 0 . 0 6 0 2 7 . 0 0 2 0 0 1 2 0 0 2 3 . 5 1 5 6 0 0 . 0 2 9 1 2 4 5 0 0 . 0 8.4 0 . 0 0 2 0 0 1 2 0 0 3 0 . 0 1 4 3 6 0 . 0 3 9 9 2 2 0 0 . 0 3 6 2 3 . 5 0 2 0 0 1 2 0 0 4 0 . 0 1 4 4 1 0 . 0 4 4 1 1 4 1 4 0 . 0 2 4 2 7 . 5 0 2 0 0 1 2 0 0 5 8 . 7 1 2 2 3 0 . 0 73 1 0 4 2 2 2 0 . 0 2 3 1 4 N. 0 . 2 0 0 1 2 0 0 6 0 . 0 1 1 4 2 0 . 0 4 4 1 7 7 7 7 0 . 0 1 2 3 0 2 ? 0 . 5 0 2 0 0 1 2 0 0 7 5 . 5 1 3 7 7 0 . 0 9 9 6 2 2 2 5 0 . 0 2 0 6 7 N . 0 . 2 0 0 1 2 0 0 3 4. 4 1 3 8 5 . 0 . 0 1 1 0 15 46 2 2 0 . 0 1 1 3 ? N. 0 . 2 O 0 1 2 O 1 O 5 . 2 1 3 3 9 0 . 0 1 1 0 1 1 3 4 1 9 0 . 0 4 8 3 7 1 2 . 0 0 2 0 0 1 2 0 1 1 3 . a 1 1 6 6 5 1 . 7 47 7 2 5 1 8 0 . 0 2 3 1 2 4 . 0 0 2 0 0 1 2 0 1 3 1 8 . 3 1 1 6 6 0 . 0 2 4 1 9 C 7 1 6 0 . 0 3 2 3 4 41 . 0 0 2 0 0 1 3 0 0 1 3 . 5 1 5 2 2 0 . 0 1 7 3 ? 2 0 3 2 0 . 0 2 7 1 M. 0 . 2 0 0 1 5 0 0 4 9 . 1 1 4 5 3 0 . 0 1 8 3 7 5 6 7 1 3 5 C O 4 6 5 N . D . 2 C C 1 " 0 0 4 5 . 8 8 5 8 0 . 0 37 1 9 Q 3 2 2 0 . 0 1 0 3 0 . 2 9 2 0 C 2 0 0 0 3 0 . C 8 1 3 0 . 0 73 8 0 7 6 5 1 0 . 0 1 0 1 N . 0 . 2 C C 2 1 0 0 1 7 . 0 3 0 7 6 0 . 0 1 3 4 373 5 1 0 . 0 3 6 8 1 . 1 2 2 C C 2 1 O 0 2 8 . 3 3 0 7 6 0 . 0 1 6 3 2 0 9 6 4 0 0 . 0 1 0 5 1 . 8 3 2 0 0 2 3 0 1 0 2 . 6 2 2 4 2 0 . 0 2 1 1 6 5 35 0 . 0 755 0 . 2 3 2 0 0 2 3 0 2 4 0 . 0 2 0 4 0 0 . 0 37 1 7 5 3 0 0 . 0 ? 5 ? 0 . 2 3 2 O C 2 3 0 5 5 0 . 0 1 6 7 2 0 . c 34 3 4 4 1 5 0 . 0 1 0 3 3 10 . 0 0 2 0 0 2 3 0 6 0 0 . 0 2 5 5 5 0 . 0 1 3 2 5 4 4 6 0 . 0 2 0 5 3 . 4 0 2 0 C 2 3 0 6 1 0 . 0 2 1 3 3 0 . 0 1 6 2 4 1 4 1 0 . 0 1 7 9 2 . 4 0 2 0 C 2 3 0 9 6 3 . 0 2 C 4 0 0 . 0 5 . 4 2 1 53 0 . 0 4 6 3 0 . 0 0 2 0 0 2 3 0 9 7 0 . 0 1 9 3 3 0 . 0 2 1 2 9 9 4 1 C O 2 3 9 0 . 4 9 2 0 0 2 3 1 2 6 6 . 1 2 5 1 1 0 . 0 1 2 4 1 1 4 6 C O 5 7 3 0 . 0 0 2 0 0 2 3 1 2 7 0 . 0 ' 2 3 4 1 0 . 0 8 1 75 35 0 . 0 59 0 . 6 5 2 0 0 2 3 1 2 3 5 . 2 2 8 4 1 0 . 0 1 3 1 2 8 3 4 0 0 . 0 7 6 6 0 . 4 8 2 0 0 2 3 1 2 9 3 . 0 2 7 6 2 0 . 0 1 2 . 2 7 0 43 0 . 0 5 6 5 0 . 47 2 0 0 2 3 1 3 6 0 . 0 2 1 1 4 0 . 0 1 5 1 7 9 3 6 0 . 0 3 0 3 0 . 44 2 0 0 2 3 1 3 8 4 . 9 2 3 0 0 0 . 0 1 2 1 7 5 4 8 C O 7 4 9 0 . 7 1 2 0 0 2 3 1 4 0 2 . 7 2 7 2 4 0 . 0 1 3 2 5 9 43 0 . 0 3 8 6 0 . 54 2 0 0 2 3 1 4 1 0 . 0 2 0 0 0 0 . 0 5 1 6 5 3 6 0 . 0 4 6 3 0 . 3 2 2 0 0 2 3 1 4 2 0 . 0 1 9 4 5 0 . 0 6 1 8 3 34 0 . 0 3 2 3 0 . 1 9 2 0 0 2 3 1 4 4 0 . 0 2 6 C 3 0 . 0 9 2 3 6 47 0 . 0 4 7 6 0 . 44 2 0 C 2 3 1 5 3 1 . 3 2 1 1 4 0 . 0 4 1 8 5 3 6 0 . 0 7 6 0 0 . 2 3 2 0 C 2 3 1 5 4 0 . c 2 3 6 5 0 . c 4 2 9 0 37 0 . 0 6 5 0 0 . 2 0 2 0 0 2 3 1 5 5 3 . 0 2 4 7 7 0 . 0 9 4 5 8 3 6 0 . 0 2 2 2 0 . 6 1 2 0 C 2 4 0 0 1 5 0 . 0 1 7 9 3 0 . 0 8 3 5 7 2 2 8 0 . 0 2 8 1 2 . 2 0 2 0 C 2 4 0 0 3 53. 6 1 3 7 4 0 . c 1 9 2 1 5 7 3 6 0 . 0 7 9 3 N . D . 2 0 0 2 4 0 0 5 3 2 . 5 1 6 1 5 0 . 0 4 0 1 0 5 8 2 4 0 . 0 1 4 6 3. 2 0 2 O C 2 4 0 0 7 8 . 2 1 5 7 4 0 . 0 5 2 5 1 1 7 4 6 0 . 0 3 0 0 . C O 2 0 0 2 4 0 0 8 1 9 . 1 1 6 4 8 0 . 0 3 8 3 4 0 8 0 . 0 0 2 . 5 0 2 0 0 2 4 0 1 1 1 6 . 0 1 6 2 9 0 . 0 8 5 1 6 1 9 0 . 0 6 2 1. 0 0 2 0 C 2 5 0 0 1 0 . 0 1 6 1 8 0 . 0 73 4 8 1 8 0 . 0 1 8 0 . 0 0 2 0 0 2 5 0 0 2 0 . 0 1 7 5 2 0 . 0 2 0 3 4 0 3 0 . 0 0 1 4 . 5 0 2 0 C 2 5 0 0 3 1 . 8 1 3 0 3 0 . 0 1 3 1 4 4 9 9 0 . 0 1 7 1 8 . 5 0 2 0 C 2 5CC5 1. 3 1 5 2 6 0 . 0 7 2 0 2 2 8 0 . 0 0 12 . 00 2 0 0 2 5 C 0 6 6 . 1 1 4 0 0 0 . 0 2 6 1 9 8 8 8 C O 2 1 N . 0 . 2 0 0 2 5 C 1 0 0 . 0 1 4 1 6 o . o 2 6 1 6 9 3 5 0 . 0 1 2 1 2 . , 5 0 2 0 0 2 5 0 1 1 1 . 9 1 8 2 0 . 0 . 0 1 0 0 1 5 8 9 1 0 0 . 0 1 9 2 2 2 . 5 0 2 0 0 2 5 0 1 2 2 . 5 1 6 4 1 0 . 0 6 0 1 9 0 0 5 0 . 0 3 6 1 7 . 0 0 52 TABLE 3-7 (CONT INUEOI ID.NT; AG c n c n c u FE MN NI P3 HG 20027003 0. 0 2099 12.4 13 1071 34 0.0 536 170 .00 2CC2700A 0. 0 1937 0.0 4 5 5527 3^ 0.0 6545 157 .00 20C3200I 69. 4 1 170 0.0 10 155 142 0.0 1512 2 .40 20C34001 0. 0 1 176 0.0 198 726 35 0. 0 56 0 .00 20034002 0. 0 1381 0.0 29 4629 23 0.0 30 9 .70 20034003 0. 0 1134 0.0 21 53 03 1 0 0.0 28 34 .50 20034005 0.0 1584 0.0 50 537? 15 0.0 p 26 . 00 20034011 5. 7 1015 • C O 63 5561 1 1 0.0 40 26 .50 20035001 5. 5 1184 0.0 366 290 28 0.0 29 0 .00 20 03 5002 0. 0 1161 0. 0 61 7 3143 4 0.0 1500 6 .50 20035003 0. 0 1709 0. 0 33 1 •245 22 0.0 0 5 .70 200"<5006 0.0 1 52 3 0. 0 210 2487 5 69.9 22 N . D. ?r"?500] 0.0 860 12.4 26 2729 8 0.0 0 4 .50 20C36003 6. 7 1836 13. 8 297 1 2435 5 0.0 36 7 .80 20036005 0. 0 1872 0.0 97 442 1 46 0.0 16 4 .00 2CC36C06 0. 0 2042 0. c 71 3 70 4 0.0 22 4 .00 20037COI 50. 6 1964 0. 0 28 1 725 31 C O 175 0 .03 20037002 2.5 1910 0.0 126 2763 10 0.0 20 0 .12 20033001 0. 0 1176 0.0 152 602 35 0.0 0 11 .80 20039001 11. 1 1196 0.0 ! 3 6365 49 0.0 71 2 .31 20C40001 0. 0 16S2 0. 0 21 3521 18 0.0 .74 10 .00 20040002 0.0 1604 0.0 21 3368 13 C O 68 10 .20 20C40003 0.0 9424 0.0 87 406 18 0.0 13 9 .20 3.5 A p p l i c a b i l i t y of Results 53 Sphalerite tends to e x h i b i t considerable v a r i a t i o n i n composition on small scales and studies based on chemical analyses which do not-take t h i s v a r i a b i l i t y into account are sometimes questioned. Rose (1967) has documented the va r i a t i o n s across a s i n g l e zoned c r y s t a l of s p h a l e r i t e using spectrographic analyses on sam-ples d r i l l e d from each zone (Figure 3-4). The v a r i a t i o n s are of d i f f e r i n g magni-tudes f o r each element; cadmium i s very stable throughout, but cobalt or n i c k e l 10 9 8 7 6 5 4 3 2 I 53IA 530 FIGURE 3-4 .VARIATIONS IN MINOR ELEMENT CONCENTRATIONS ACROSS A ZONED•SPHALERITE CRYSTAL AND IN TWO ADJACENT MASSIVE SPECIMENS ( a f t e r Rose, 1967). Sketch shows colour zones and sample locations i n the c r y s t a l . 54 v a r i a t i o n s approach an order of magnitude. Rose also compares these zoned s p h a l e r i t e analyses with those of two massive s p h a l e r i t e .samples taken adjacent to the zoned c r y s t a l . This comparison i s more i n d i c a t i v e of the 'within d e p o s i t 1 minor element v a r i a t i o n s , which i n t h i s case, r e f l e c t trends s i m i l a r to the s i r g l e c r y s t a l v a r i a t i o n s . The possible s i g n i f i c a n c e of these v a r i a t i o n s i n r e g i o n a l studies can not be overlooked. Spectrographic or e l e c t r o n microprobe analyses of a t i n y section of a s i n g l e s p h a l e r i t e sample w i l l not be representative of the ent i r e hand specimen, and the deviation from the mean analysis f o r a regional group of specimens w i l l be larger than necessary 3 thereby possibly masking some of the more subtle regional v a r i a t i o n s . 'Homogenization' of each s p h a l e r i t e sample (as has been done i n t h i s study), whether zoned or not, reduces intra—sample v a r i a t i o n and y i e l d s a minor element content character-i s t i c of the o v e r a l l phase of m i n e r a l i z a t i o n , including elements adsorbed from the ore solutions which would not otherwise be detected i n x-ray c r y s t a l l o g r a p h i c methods. Therefore i n a regional study of t h i s nature, a representative picking of a hand specimen, followed by crushing and 'homo-genization', produces r e s u l t s applicable on a d i f f e r e n t scale than those of Rose (ibi d . ) . Regional a p p l i c a b i l i t y of r e s u l t s i n this study i s confirmed by the following analyses of variance. In order to i n v e s t i g a t e the e f f e c t s of small scale chemical v a r i a t i o n s (of the type Rose has i l l u s t r a t e d ) on the a n a l y t i c a l r e s u l t s obtained'in t h i s study, an analysis of variance was designed, based on the 17 samples that were separated twice. These samples y i e l d pairs of analyses which r e f l e c t the small scale sample variances a t t r i b u t a b l e to sampling two d i s t i n c t parts of a s i n g l e hand specimen. The o r i g i n a l sample from each of the 17 picked twice was also analyzed twice i n order to allow d i f f e r e n t i a t i o n of a n a l y t i c a l variances from sampling variances. Therefore, the 17 hand specimens were a c t u a l l y analyzed i n t r i p l i c a t e . Appendix C (Figure C-l) 5 5 i l l u s t r a t e s this procedure and tabulates the a n a l y t i c a l data pairs generated (Table C - l ) , Also included i n Appendix C i s a discussion of the analysis of variance technique applied to th i s group of t r i p l i c a t e d analyses from single hand specimens. Two analyses of variance were performed on this data. I n i t i a l l y , the combined variances due to hand sampling and analysis were compared to the variance due to analysis alone. The results (Table C -2) indicate that these two sources of variance are of the same magnitude for each element, i . e . the v a r i a b i l i t y introduced through sampling the same specimen twice i s n e g l i g i b l e r e l a t i v e to a n a l y t i c a l v a r i a b i l i t y . Secondly, the a n a l y t i c a l and hand specimen sampling variances within a single deposit were compared to those variances between the deposits, i n order to determine i f data variances incurred during analysis are large enough to conceal natural sample variances between deposits. The results of thi s test are compiled i n Table C—2 and. indicate that i n a l l cases the within deposit variance i s n e g l i g i b l e r e l a t i v e to the between deposit variance and natural sample va r i a t i o n s . These two tests indicate that 1 ) the a n a l y t i c a l data variances are low re l a t i v e to the between deposit variances,. and 2 ) the separation and crushing procedure used produces a uniform sample which i s representative of the hand specimen. Therefore, the conclusions that can be drawn are that the analy-t i c a l results are: 1 ] not complicated by numerous small scale minor element variations, 2 ] representative of the minor element content of the sphalerite as generated by a phase of mineralization, and 3 ] applicable on a regional scale investigation of the minor element contents of sphalerite. A further analysis of variance comparing sample variances within deposits 56 and between deposits, discussed i n Chapter 5 (section 5.3), confirms and strengthens these conclusions. The above statements i n d i c a t e that the a n a l y t i c a l technique i s a minor source of v a r i a b i l i t y i n the data, however i t i s the only source over which any controls-can be maintained i n t h i s study. An i n v e s t i g a t i o n of the error sources generated within the a n a l y t i c a l procedures can y i e l d independent guidelines on the a p p l i c a b i l i t y of the r e s u l t s . Therefore, the following discussion defines a n a l y t i c a l error sources and o u t l i n e s the l i m i t a t i o n s they place on the r e s u l t s . Each phase of the a n a l y t i c a l treatment of the sample s u i t e might c o n t r i -bute error into the f i n a l r e s u l t . These errors can add up to a s i g n i f i c a n t percentage:^in a study of t h i s nature, thus, i t i s e s s e n t i a l to survey and b r i e f l y discuss the possible sources and t h e i r contribution to the o v e r a l l a n a l y t i c a l e r r o r . This discussion examines each step of the a n a l y t i c a l procedure and summarizes any l i m i t a t i o n s imposed on the a p p l i c a b i l i t y of r e s u l t s . Since most minor element analyses u t i l i z e a mineral separate, they are subject to error due to contamination of the separate by 'foreign' minerals ( c f . Mercer, 1976, p, 3). Such contamination i s probably the major source of error i n a few samples studied here. In t h i s project the mineralogy of the deposits sampled tends to be r e l a t i v e l y simple and samples with coarse grained s p h a l e r i t e were preferred to f a c i l i t a t e separation of a pure sphal-e r i t e . Nevertheless, i n c l u s i o n of traces of p y r i t e , galena, or chalcopyrite could not be e n t i r e l y avoided and can add detectable proportions of th e i r major elements which, are s i g n i f i c a n t r e l a t i v e to the true concentrations of these i n the s p h a l e r i t e i t s e l f . Traces of c a l c i t e , dolomite, and quartz were l o c a l l y included i n the sp h a l e r i t e samples, however these contaminants do not contain large amounts of any of the metals of i n t e r e s t , therefore t h e i r i n c l u s i o n would not have any appreciable e f f e c t on metal analyses. 57 The separated samples were,pulverized i n an alumina-ceramic Spex shaker m i l l since t h i s method would not contaminate the samples with any metals of i n t e r e s t . Carry over contamination of one sample to the next was kept to a minimum by cleaning the m i l l thoroughly with compressed a i r between each sample, as w e l l as with acetone and a i r ' a t regular i n t e r v a l s . Emission arc spectrographic r e s u l t s are generally not r e l i a b l e due to errors inherent within the a n a l y t i c a l technique (see section 2,3.1). Further problems include uneven sample burns and unevenidevelopment of s p e c t r a l photographic p l a t e s . These d i f f i c u l t l y c o n t r o l l e d f a c t o r s , plus the l i m i t a -t i o n of v i s u a l comparison with standard pla t e s , lead to poor re p r o d u c a b i l i t y of r e s u l t s . Furthermore, the comparison of sulphide matrix samples with g r a n i t i c matrix standards introduced unknown matrix e f f e c t s i n t o the r e s u l t s . The r e l i a b i l i t y of the spectrographic data was tested by computing a c o r r e l a -t i o n matrix between the quantitative atomic absorption r e s u l t s and the CO <U cn TABLE 3-8 CORRELATION OF ANALYTICAL METHODS Cor r e l a t i o n of 162 sample analyses f o r seven elements determined on both atomic absorption and emission spectrographic methods ( c o r r e l a t i o n c o e f f i c i e n t at the 99% s i g n i f i c a n c e l e v e l i s 0.180). Atomic Absorption Analyses Ag Co Cu Fe Mn Ni Pb Ag .7126 Co .7196 ca a < Cu .7179 o u •H -H CO J3 -co PL, 2 Mn .6092 o u u CJ <D P, CO Fe .5368 Ni .1898 Pb .8792 58 emission spectrographic data. The re s u l t s of t h i s c o r r e l a t i o n , provided i n Table 3-8, i n d i c a t e a very high c o r r e l a t i o n of a n a l y t i c a l methods for the seven elements i n common, at the 99% s i g n i f i c a n c e l e v e l . This shows that the emission spectrographic method probably provides semi-quantitative r e s u l t s fo r these elements and indicates that analyses of the remaining elements probably are r e l i a b l e at the semi-quantitative l e v e l . S p e c i f i c a l l y , u t i l i -z ation of the emission spectrograph data to confirm element d i s t r i b u t i o n s at the q u a l i t a t i v e presence or absence l e v e l i s a reasonable approach. Atomic absorption spectrographic analysis i s a p o t e n t i a l l y more quanti-i t a t i v e technique, however, errors due to the analyst's care and a n a l y t i c a l s k i l l , and to matrix e f f e c t s w i t h i n the material being,analyzed, can occur. High zinc matrix e f f e c t s appear to be uninvestigated, but since each sample has a s i m i l a r matrix, these e f f e c t s are constant throughout the analyses and w i l l not bias any i n d i v i d u a l samples. Throughout the procedures, a l l g l a s s -ware was thoroughly washed between samples and rinsed i n acid s o l u t i o n s , and storage b o t t l e s were cleaned, rinsed i n aci d , and rinsed with sample so l u t i o n s . The t o r s i o n balance used to weigh out samples i s accurate to +0,02 mg. F i n a l volumes, and hence concentrations, were accurately obtained using 25 ml volumetric f l a s k s . Standard solutions, prepared from stock s o l u t i o n s , provided r e l a t i v e l y l i n e a r absorbance c a l i b r a t i o n graphs. The minimum deviations which could be determined f o r each element are given i n Table 3-9. The small sample weights used to a l l e v i a t e the p l a s t i c sulphur problem, unfortunately resulted i n a d i l u t i o n f a c t o r of 125 being applied to r e s u l t s determined from the c a l i b r a t i o n graphs; a n a l y t i c a l errors incurred to t h i s point were also magnified by t h i s f a c t o r . Limitations of the above method appear to be quite small but 'analyst error* remains non-quantifiable. Determinations of o v e r a l l a n a l y t i c a l p r e c i s i o n and an analysis of the a n a l y t i c a l and natural sample variances between and with i n deposits provides 59 TABLE .3t9 MINIMUM DEVIATIONS DISCERNIBLE ON ATOMIC ABSORPTION UNITS (converted to ppm at minimum d i l u t i o n factor) Instrument used- a: Perkin Elmer b: Varian Techtron Ag Cd Cu Co 1 (a) 2 (a) 1 (a) 3 (b) Mn Ni Fe Pb 4 (b) 1 (b) 1 (a) 3 (a) an estimate of the a p p l i c a b i l i t y of these r e s u l t s . These c a l c u l a t i o n s , tabulated i n Appendix C and discussed previously, i n d i c a t e that those elements with the widest range of absolute values and the best p r e c i s i o n w i l l define regional d i s t r i b u t i o n s w e l l . Consequently, cadmium, s i l v e r , and perhaps i r o n and manganese probably provide the most r e l i a b l e information. Part of the 'natural sample variance* could be due to contamination of the s p h a l e r i t e samples by associated sulphide minerals. Very f i n e grained p y r i t e or galena, intimately associated with the s p h a l e r i t e , was included i n some samples, hence anomalously high i r o n and lead values are suspect. In those samples with associated copper m i n e r a l i z a t i o n (Appendix A) some copper values are also suspect. However, s p h a l e r i t e might contain an increased concentration of i r o n , lead, or copper, through increased adsorption, absorption, and s o l i d s o l u t i o n , when formed from solutions s u f f i c i e n t l y enriched i n these elements to also p r e c i p i t a t e p y r i t e , galena, or chalco-p y r i t e . Therefore i t i s very d i f f i c u l t to quantify the degree of contamin-ation from included p a r t i c l e s . A q u a l i t a t i v e measure of possible contaminants, can be found i n .the generalized mineralographic descriptions f o r each deposit (Appendix 1), The hand specimen and polished section descriptions do not cover every specimen thoroughly, but they are representative of the micromineralogy of 60 a given deposit. These descriptions i n d i c a t e that f i n e , carbonate f i l l e d fractures are common to many samples, and expectedly traces of carbonate minerals were included i n th i s manner. Important metal-bearing sulphides, however, were r a r e l y seen d i s t r i b u t e d throughout the sp h a l e r i t e samples. Table 3-10 provides an example of the i n t e r p r e t a t i o n of data suspected of contamination or anomalous to a d i s t r i b u t i o n pattern, i n terms of the information a v a i l a b l e . Seemingly anomalous values were compared with miner-alographic descriptions to check on the v a l i d i t y of the s p h a l e r i t e analyses. S i g n i f i c a n t p y r i t e or galena contamination can possibly lead to trace contaminations of cobalt and n i c k e l or s i l v e r r e s p e c t i v e l y , since these elements are more commonly found as minor constituents of these minerals (Price, 1972; Nishiyama, 1974) . Contamination due to minor elements of a contaminant mineral i s nowhere expected to be s i g n i f i c a n t since (1) the quantity of any contaminant mineral included i s very low, and (2) the concentration of a minor element present i n only trace quantities of contam-inant, i s highly d i l u t e d within the sp h a l e r i t e separate. Consideration of the magnitude and sources of the error i n the data leads to the conclusion that the a n a l y t i c a l r e s u l t s are applicable to a regional study of t h i s nature. Special care must be taken to i n t e r p r e t anomalous values. Therefore, regional i n t e r p r e t a t i o n s of the atomic absorption spectrographic data can proceed within the above g u i d e l i n e s l i n f u l l confidence of determining d i s t r i b u t i o n patterns representative of the true minor element content of the s p h a l e r i t e s . Emission spectrographic data can also be used, w i t h i n the guidelines previously stated f o r i t , to develop or v a l i d a t e regional patterns. 61 TABLE 13-10 INTERPRETATION OF ANOMALOUS DATA IN TERMS OF MINERALOGIC DATA AVAILABLE Deposit Number A n a l y t i c a l Results Paragenetic (ppm) Associations Fe Pb Conclusions 10006 12,416 1,245 -sparry c a l c i t e v e i n l e t s -no other sulphides observed -second highest Fe content recorded yet no primary Fe minerals observed —accept a n a l y t i c a l values 10030 12,140 10,750 -p y r i t e and galena replace s p h a l e r i t e l o c a l l y -high Fe and Pb re s u l t s c o r r e l a t e with possible con-taminants — r e j e c t r e s u l t s because they are l i k e l y non-repres-entative of sphal-e r i t e alone 10032 35,870 3,879 -dolomite and sphal-e r i t e -no other sulphides observed -high Fe and Pb r e s u l t s , yet no other sulphides observed -accept a n a l y t i c a l r e s u l t s 20020 8,076 101 -p y r i t e occurs with carbonates i n fractures i n s p h a l e r i t e -moderate Fe r e s u l t with possible contaminant noted -nise a n a l y t i c a l r e s u l t with caution ( i . e . Fe i s possibly too high) 20034 4,518 42 -galena present i n twin lamellae of some deformed s p h a l e r i t e -high Fe r e s u l t but no p y r i t e observed -possible galena contaminant but low Pb analysis -accept a n a l y t i c a l r e s u l t s 62 CHAPTER 4: REGIONAL GEOLOGY OF THE NORTHERN YUKON  AND ADJACENT DISTRICT OF MACKENZIE 4.1 Introduction The physiography of the Canadian c o r d i l l e r a north and east of the T i n t i n a trench i n the Yukon T e r r i t o r y and adjacent D i s t r i c t of Mackenzie i s dominated by arcuately folded, and thrusted, b e l t s of carbonate rocks which are separated by intervening plateaux and basins. Carbonate u n i t s represent the continuation of the Rocky Mountain b e l t of B r i t i s h Columbia, but are much more varied i n character, hence they contain more physiographic sub-d i v i s i o n s (Figure 4-1). St r u c t u r a l subdivisions, to be discussed subsequent-l y , generally follow the physiographic patterns, r e f l e c t i n g s t r u c t u r a l and s t r a t i g r a p h i c controls over physiography. Detailed descriptions of the physiography can be found i n Bostock (1946, 1970). The Selwyn and Mackenzie Mountains (Figure 4-1) are northerly trending features, separated by a l i n e o r i g i n a l l y intended to separate r e s p e c t i v e l y , sedimentary rocks containing i n t r u s i v e s from those that are s t r i c t l y s e d i -mentary. These mountains swing to the west and are successively described as the Wernecke and O g i l v i e Mountains. The Richardson Mountains are a shale-carbonate b e l t which trends north from the Wernecke Mountains . A northward swing from the O g i l v i e Mountains extends into the carbonate rocks of the Northern O g i l v i e Mountains 1. Due to recent e f f o r t s of the Geological Survey of Canada and of exploration companies, the geology of t h i s area i s becoming i n c r e a s i n g l y 1 Bostock (1970) has regrouped the Northern O g i l v i e Mountains i n t o the Nahoni and Porcupine Ranges, as shown i n Figure 4-1, however, the term Northern O g i l v i e Mountains w i l l be applied i n t h i s t h e s i s . FIGURE 4-1: PHYSIOGRAPHIC REGIONS OF THE NORTHERN CORDILLERA ( a f t e r Bostock, 1970) 64 understood. The s t r a t i g r a p h i c framework, s t r u c t u r a l s t y l e s and o v e r a l l tectonic evolution has been discussed by various authors (Gabrielse, 1967; Douglas et a l . , 1970; Lenz, 1972; Norri s , 1972, 1974), hence nordetailed d e s c r i p t i o n i s attempted here. The following summarizes the regional geology and emphasizes the s t r a t i g r a p h i c and s t r u c t u r a l r e l a t i o n s h i p s most pertinent to the carbonate-hosted zinc-lead mineral deposits discussed i n i t h i s t h e s i s . A regional geologic map i s presented i n Figure 4-2 f o r reference. Paleophysiographic features pertinent to sedimentologic controls discussed here, are p l o t t e d i n Figure 4-3. A diagrammatic cross-section (Figure 4-4) and a time-space p r o j e c t i o n ^ (Figure 4-5) have also been compiled i n order to further i l l u s t r a t e the s t r a t i g r a p h i c r e l a t i o n s and t h e i r possible r e l a t i o n to zinc-lead m i n e r a l i z a t i o n . 4.2 Stratigraphy Proterozoic and Paleozoic sedimentary rocks which have been faulted and folded, but not heavily metamorphosed, comprise the main b e l t s of i n t e r e s t through the Mackenzie, Wernecke, O g i l v i e , and Richardson Mountains. Two facies dominate the rock d i s t r i b u t i o n both i n space and through time; folded and weakly metamorphosed argillaceous rocks of the Selwyn shale basin grade l a t e r a l l y north and east into a miogeoclinal wedge of predominantly carbonate sediments onlapping the craton (Figure 4-3 i l l u s t r a t e s the general d i s t r i b u t i o n of Ordovician to Early Devonian f a c i e s around the mountain b e l t s ) . C r y s t a l l i n e basement material i s nowhere exposed,, however topographic or ^ The time-space pro j e c t i o n was drawn to h i g h l i g h t the temporal re l a t i o n s h i p s of the l i t h o s t r a t i g r a p h i c units hosting the zinc-lead m i n e r a l i z a t i o n . S p e c i f i c features were ^ projected' onto 1 the section, around arcuate l i n e s .". approximating the curve of the Mackenzie Mountain b e l t . Projection of this amount of data onto a sing l e section necessitates some generalizations be made i n facies r e l a t i o n s and po s i t i o n s ; some of these generalizations are mentioned i n the text. FIGURE 4-2: REGIONAL GEOLOGY OF THE NORTHERN CORDILLERA Refer to Appendix B for c o r r e l a t i o n chart and references. ON ON FIGURE 4-3: PALEO-PHYSIOGRAPHIC REGIONS OF THE NORTHERN CORDILLERA Dashed l i n e divides equal thicknesses of Ordovician to early Devonian aged c l a s t i c rocks (to the south and west) from carbonate rocks (to the north and east), ( a f t e r , Copeland, 1977). Line A-B defines the p o s i t i o n of the cross-section (Figure 4-4) and the time-spa p r o j e c t i o n (Figure 4-5). 67 s t r u c t u r a l features i n the basement might have aided i n e s t a b l i s h i n g the Proterozoic sedimentologic controls which survived, i n general form, u n t i l Devonian time. Middle Proterozoic sandstones, s i l t s t o n e s , a r g i l l i t e s and orange weathering carbonate units comprise the oldest sediments i n the area. These units are equated with Purcell-type sedimentation bordering the craton i n southern B r i t i s h Columbia and Alberta (Douglas et a l . , 1970) and are interpreted to have been formed as a miogeoclinal wedge of sedimentary rocks derived from the craton to the east. H e l i k i a n rocks are represented by a number of formations, including G.S.C. un i t HI, Tsetozene, Katherine, H5, and L i t t l e Dal, plus t h e i r equivalents (Figure 4-5, c.f . c o r r e l a t i o n chart and geologic map, refeorehces'j Appendix B) . The HI, Tsetozene, and Katherine units comprise a generally conformable sequence of i n t e r c a l a t e d quartzite^ s i l t s t o n e , shale and dolomite. Fine cross laminae, mudcracks, and stromatolites i n d i c a t e a shallow water o r i g i n and a thinning onto the craton to the east. Blusson (1974a,b) records a s i m i l a r succession i n units Hcs and Hsc ( c o r r e l a t i o n chart, Appendix B) i n the Wernecke Mountains. Here, f i n e grained c l a s t i c and impure carbonate rocks grade upward through a ferruginous cherty member i n t o a shallow water a r g i l l i t e sequence. Many of the p e l i t i c members of t h i s group have under-gone low grade r e g i o n a l metamorphism. Laznicka (1977) and B e l l (1978) in d i c a t e that an extensive area of Proterozoic sediments from the Wernecke Mountains westward into the O g i l v i e Mountains, contains scattered copper, cobalt, and possibly uranium m i n e r a l i z a t i o n . Commonly t h i s m i n e r a l i z a t i o n i s associated with large areas of s i l i c e o u s and ferruginous breccias and with d i o r i t e dykes and s i l l s (Archer et a l . , 1976). Fine e l a s t i c s , found as blanket u n i t s i n the lower H5 group, grade upwards into a depositional shallowing sequence of b a s i n a l shales and DIAGRAMMATIC CROSS-SECTION, SELWYN BASIN TO MACKENZIE MOUNTAINS ( l i n e A B i n Figure 4-3) (adapted from Aitken et a l . , 1972; Douglas et a l . , 1970; and C e c i l e , 1978) D E V 0 N I A N L U R UPR MIO. LOW. UPR H A D R Y N I A N H E L I K I A N p b - z n - b a be na hd J3L ' o c o *> c o * v v \s.v ygy v \ ] v \ \ \ \ \ - — M b \ \ \ \ \ \ r r \ d i \ \ A \ v V v \ v 0 : 0 ^ \ \ V Ve \a \ t\ \ \ > \ M \ \ \ , \ 0 0 0 \^ 0 0 \ Vi V)' ( 0 \ V V -s 9 -A i * V I I 0 j « o I 0 \ A A ,N A ,\ ,N .\-A_hc. S .S A A A > \ \' V \ - c w — b b b b \ \ \ \ i h» e - c c -* *~ — — \ " sc ho IT7Z-7 ^8 .—. \ \ \ \ - ^ \ t»\ \ \ A \ ; / v g L I t h o l o g l e s l i m e s t o n e d o l o m i t e s h a l e s a n d s t o n e c o n g l o m e r a t e c h e r t c c ee e v a p o r i t e s vv v o l c a n i c t u f f s bb b a s i c f l o w s 3 S d y k . e s , s i l l s - t f V _ b i o h e r m s , r e e f s fe i r o n f o r m a t i o n Cu c o p p e r m i n e r a l i z a t i o n zn-pb-ba z i n c - l e a d - b a r i t e m i n e r a l i z a t d o n z i n c - l e a d d e p o s i t s s t u d i e d i n t h i s p r o j e c t : w i t h i n t h e M a c k e n z i e A r c h ® a r e a o u t s i d e t h e M a c k e n z i e A r c h Kl a r e a LEGEND P h y s i o g r a p h i c a n d  G e o l o g i c F e a t u r e s wi/>^ u n c o n f o r m i t i e s y-t^t^y f a c i e s t r a n s i t i o n — ' f a u l t s MCE M i s t y C r e e k Embayment MA M a c k e n z i e A r c h RA R e d s t o n e A r c h TU T w i t y a U p l i f t SB S e l w y n B a s i n V v o l c a n i c c e n t r e R e f e r e n c e s 1 G a b r i e l s e , 1967 2 A i t k e n e t a l . , 1972 3 C e c i l e , 1 9 7 8 a , b 4 Cook and A i t k e n , 1978 5 D o u g l a s e t a l . , 1970 6 A i t k e n , 1977 7 E i s b a c h e r , 1977 8 L a z n i c k a , 1977 9 L e n z , 1972 10 D a w s o n , 1977 11 B l u s s o n , 1976 F o r m a t i o n s na N a h a n n i l i d H e a d l e s s l a L a n d r y a r - A r n i c a s o Sombre c a C a m s e l l d l D e l o r m e b e ' B l a c k c l a s t i c ' wh W h i t t a k e r mk M t . K i n d l e fm F r a n k l i n M o u n t a i n r r Road R i v e r s r S a l i n e R i v e r mc M t . Cap s k S e k w i b r B a c k b o n e R a n g e s s h S h e e p b e d k e K e e l e r a R a p i t a n I d L i t t l e D a l " h 5 H5 k a K a t h e r i n e t s T s e z o t e n e h i HI FIGURE 4-5: TiME-SPACE PROJECTION OF MACKENZ (Projected IE MOUNTAINS, WERNECKE MOUNTAINS onto line AB in Figure 4-3) AND SELWYN BASIN STRATIGRAPHY 70 carbonates which host spectacular bioherms over 900 metres high (Aitken, 1977). These re e f s , commonly with c r y p t a l g a l cores and flanking talus deposits, form a weak trend s u b p a r a l l e l to the present physiographic and s t r u c t u r a l trends. A widespread s u b t i d a l e v a p o r i t i c u n i t of considerable thickness follows the H5 dolomite deposition and i s i n turn followed by p y r i t i f e r o u s shale and carbonate u n i t s . Thick carbonate rocks of the L i t t l e Dal Formation continue shallow water bank deposition u n t i l the end of H e l i k i a n time (Aitken, i b i d . ) . Embayments along the craton shoreline c o l l e c t e d a sequence of fanglomerates i n t e r c a l a t e d with dolomitic sand-stones containing c r y p t a l g a l laminites i n d i c a t i v e of a s u p r a t i d a l mudflat environment (Eisbacher, 1977) . These rocks form the narrow b e l t of the Redstone Formation and bear copper m i n e r a l i z a t i o n throughout. Eisbacher (ib i d . ) believes that these embayments developed within f a u l t bounded basins as a r e s u l t of c r u s t a l d i l a t i o n which was d i r e c t l y followed by the Racklan orogeny. Purcell-type sedimentation, which was brought to a close i n southern B r i t i s h Columbia by the East Kootenay orogeny, was brought to an end i n the north by the Racklan orogeny. Miogeoclinal conditions did not p e r s i s t a f t e r a general u p l i f t of H e l i k i a n s t r a t a , which, aided by f o l d i n g , f a u l t i n g , and erosion, led to a major regional unconformity developing p r i o r to Hadrynian sedimentation (Figures 4-4 and 4-5). Basic dykes and flows accompanied Racklan f a u l t movements which p e r s i s t e d during deposition of Hadrynian Rapitan conglomerates. The l a t e Proterozoic Rapitan Group i s c l o s e l y associated with Racklan a c t i v i t y and generally, as a r e s u l t of t h i s a c t i v i t y , i s composed of coarse to f i n e grained f e l d s p a t h i c c l a s t i c rocks. Rapitan conglomeratic f a c i e s become f i n e r upwards, with l o c a l i r o n formation, chert, and volcanic t u f f horizons, and are followed by more argillaceous and carbonate members. 71 O v e r a l l , these c l a s t i c l i t h o l o g i e s , informally termed the 'Grit U n i t ' throughout the northern c o r d i l l e r a , are thought to represent 'Windemere-type' sedimentation t y p i c a l of the southern Rocky Mountain areas (Douglas et a l . , 1970). Feldspathic contents i n d i c a t e a c r y s t a l l i n e source, possibly to the west or southwest (Gabrielse, 1967) . Laznicka (1977) has noted copper m i n e r a l i z a t i o n of possible syngenetic o r i g i n i n these lower Hadrynian a r g i l l a c e o u s rocks. The 'Grit U n i t ' passes upwards in t o carbonate rocks of the Keele Formation and the non-calcareous shales of the Sheepbed Formation; these formations complete the Proterozoic s t r a t i g r a p h i c record (Figures 4—4 and 4-5). During the lower to middle Hadrynian, depositional c o n t r o l . over sedimentary f a c i e s gradually s h i f t e d from Racklan tectonic influences to more stable basin and arch slope r e l a t i o n s ; patterns developed at t h i s time dominated f a c i e s r e l a t i o n s u n t i l the Devonian Period. Several t e c t o n i c a l l y p o s i t i v e features became dominant at various times and locations during the Paleozoic; these features are not wholly continuous and they tend to disrupt the regional sedimentary accumulations i n t o semi-restricted basins adjacent to arches. Gabrielse (1967) demonstrated the o r i g i n of the Redstone Arch during the middle Hadrynian south of Keele River (Figures 4-3 and 4-5). Aitken et a l . (1972) suggested that a hinge l i n e developed at t h i s time with i t s axis somewhat east and dominantly north of this l o c a t i o n ; t h i s feature i s the precursor to the dominant Cambrian Mackenzie Arch (Douglas et a l . , 1970) outlined i n Figures 4-3 and 4-4. The time-space pro j e c t i o n (Figure 4-5) portrays both of these features and includes Hadrynian units between th e i r l o c i projected onto the section; these units might not be present everywhere i n the Mackenzie.Mountains, p a r t i c u l a r l y i n the area d i r e c t l y east of the Redstone Arch.axis. The Proterozoic surface was bevelled r e l a t i v e l y f l a t during l a t e 72 Hadrynian erosion, thereby allowing rapid transgression of Cambrian seas over a pronounced and widespread unconformity. A uniform sequence of trans-gressive quartzites and shales of the Backbone Ranges Formation bears an early Cambrian O l e n e l l i d t r i l o b i t e assemblage extending 'from the Richardson Mountains, through the Backbone Ranges, to the South Nahanni River headwaters ( F r i t z , 1974; Green et a l . , 1967). This pattern i s the i n i t i a l expression of sediments formed adjacent to the Mackenzie Arch and extending northward in t o the Richardson Trough (Figure 4-3). The overlying b r i g h t l y coloured dolomites of the Sekwi Formation t h i n onto the Mackenzie Arch and develop three f a c i e s , consisting of 1) an inner d e t r i t a l b e l t of near shore c l a s t i c rocks, 2) a carbonate s h e l f , and 3) an outer d e t r i t a l limestone and c a l c a r -eous shale b e l t . Cambrian t r i l o b i t e s and archaeocyathid reefs are common i n the carbonate members. Thick carbonate bioherms adjacent to the Bonnet Plume high (Figure 4-3) define a Lower Cambrian hinge l i n e , separating a broad carbonate platform i n the north ce n t r a l Yukon and the Richardson trough to the east ( F r i t z , 1974). During the Latest Cambrian, a general u p l i f t of the area, centered on the eastern Selwyn Basin, produced an extensive depositional hiatus at the top of the Sekwi Formation. Middle and Upper Cambrian f a c i e s patterns were s i m i l a r to those of the Lower Cambrian, however, major e r o s i o n a ! periods at the end of the Lower and Middle Cambrian led to highly v a r i a b l e preser-vation of these u n i t s . Most of the Middle Cambrian s t r a t a was: removed and the Upper Cambrian s t r a t a thins to non-existence onto the Mackenzie Arch. Middle and Upper Cambrian units d i r e c t l y east of the arch are p a r t i a l l y preserved i n the Mt. Cap Formation limestones and s i l t s t o n e s . Gypsiferous shale and mudstone of the overlying Saline River Formation were formed wit h i n l o c a l i z e d , r e s t r i c t e d embayments present on the surface of the pre-Upper Cambrian unconformity. 73 O v e r a l l , the Cambrian period was the f i r s t to reveal the dominance of the Mackenzie Arch and i t s p a r a l l e l i n g basins and troughs over regional f a c i e s d i s t r i b u t i o n . Thick carbonate deposits accumulated along the flanks of the arch, p a r t i c u l a r l y i n the area between the present Keele and A r c t i c Red Rivers. Local e v a p o r i t i c shoreline f a c i e s and nearshore biohermal buildups occur immediately adjacent and p a r a l l e l to the trend of the arch. To the west and southwest, platy impure carbonates grade into calcareous a r g i l l i t e s d i s t a l to the arch i n the Selwyn Basin area. Figure 4-4 schem-a t i c a l l y e x h i b i t s r e l a t i o n s h i p s among the Lower Cambrian l i t h o f a c i e s ( a d j -acent to the arch), the erosional breaks, and the return to carbonate deposition i n the Lower Ordovician. Lower to Middle Ordovician F r a n k l i n Mountain Formation i s abundant along the a x i a l locus of the Mackenzie Arch and these carbonate rocks thicken r a p i d l y westward i n t o f a c i e s equivalent bedded shales, s i l t s t o n e s , and cherts of the Selwyn Basin. L o c a l l y the pre-Ordovician erosional break i s discontinuous and Upper Cambrian carbonates are continuous i n t o the Franklin Mountain Formation. During the Late Ordovician, the Mackenzie Arch and Selwyn Basin became less prominent as sedimentologic controls due to a general depression of the North American craton. However, the general patterns established by Cambrian f a c i e s p e r s i s t e d . Westward t i l t i n g and moderate f o l d i n g of the carbonates during the Middle to Late Ordovician led to an eastward b e v e l l i n g of the underlying u n i t s , therefore, S i l u r i a n rocks overly progressively older units to the east. The Mount Kindle Formation overlaps onto t h i s e r o s i o n a l break. A Middle S i l u r i a n phase of the Mackenzie Arch, the Twitya U p l i f t (Cook and Aitken, 1978), occurred along the locus of the e a r l i e r Redstone Arch. Due to the l o c a l i z e d erosion of Ordovician and S i l u r i a n carbonates i n t h i s area the overlying Delorme Formation rests unconformably on rocks as o l d as Proterozoic, The time-74 space p r o j e c t i o n (Figure 4-5) indicates the p o s i t i o n of t h i s u p l i f t , and records Ordovician to S i l u r i a n aged carbonate units immediately beneath and adjacent to i t . These carbonates were l i k e l y removed during erosion i n those areas a f f e c t e d by the Twitya U p l i f t , however they are present'ln the more northerly areas, outside the influence of the u p l i f t . Therefore, both the carbonates and the u p l i f t are plotted, but they are discontinuous around the extent of the mountain b e l t . Abrupt f a c i e s changes occur from the carbonate rocks adjacent to the Mackenzie Arch i n t o the shales of the more r e s t r i c t e d Richardson Trough to the north and the Selwyn Basin to the south and west. Active subsidence i n the trough commenced i n Late Cambrian time and continued, u n t i l E a r l y Devonian, during which time thick sequences of g r a p t o l i t i c shales, a r g i l -laceous limestones, t u r b i d i t i c limestones, and l o c a l cherty horizons accum-ul a t e d . Similar f a c i e s developed i n the Selwyn Basin where ;the carbonate component decreases away from the arch and c h e r t - r i c h horizons are present i n the centre of the basin. This thick succession of Ordovician to Devonian aged argillaceous u n i t s comprises the Road River Formation. A l i n e i n Figure 4-3 indicates the locus of approximately equal thicknesses of Ordovician to E a r l y Devonian c l a s t i c and carbonate rocks around the Selwyn Basin (Copeland, 1977) . Precise f a c i e s boundaries are highly v a r i a b l e through time and Figures 4—4 and 4-5 are drawn to i n d i c a t e transgressive— regressive r e l a t i o n s . C e c i l e (1978a,b) recently documented a major Ordovician to S i l u r i a n embayment of shales, transgressive i n t o the carbonate b e l t , c a l l e d the Misty Creek Embayment (Figures 4-3, 4-4, and 4-5). This feature was most transgressive onto the platform during F r a n k l i n Mountain carbonate formation and receded to the south and west s l i g h t l y during Mt. Kindle accumulation. Intercalated with the shales are volcanic t u f f s of Middle Ordovician to E a r l y S i l u r i a n age, d i s t r i b u t e d about a proposed volcanic 75 centre (Cecile, i b i d . ) indicated on Figures 4-4 and 4-5. Volcanic t u f f s and basic flows of th i s age have been recognized for some time (Douglas et a l . , 1970; Blusson, 1974, map unit Ov) within the Middle Ordovician Sunblood Formation i n t h i s area> , The S i l u r i a n to Devonian Delorme Formation marks the return to wide-spread carbonate p r e c i p i t a t i o n . Localized depositional controls adjacent to the shoreline produced evaporites and argillaceous l a y e r s . U p l i f t of the Mackenzie platform i n the northeast (Lenz, 1972) led to non-deposition and some erosion during t h i s time (Figure 4-5) . Overlying the Delorme Formation i s a generally conformable sequence of Devonian carbonate u n i t s broken only by a discontinuous hiatus during pre-Middle Devonian time. Depositional f a c i e s throughout the Devonian were more l o c a l i z e d and contained numerous stromatoporoid reef f a c i e s along carbonate bank to shale basin hinge l i n e s . Camsell and Sombre Formation carbonates are thickest i n the northern troughs and t h i n i n t o the Mackenzie Mountains. Arnica Formation dolomites conformably overly Sombre dolomites i n the Mackenzie Mountains. They might unconformably o v e r l i e Delorme units i n the north towards the Richardson Mountains. Middle and Upper Devonian carbonates comprise the Landry, Headless, and Nahanni Formations. A Devonian to M i s s i s s i p p i a n aged black c l a s t i c u n i t o v e r l i e s the Road River Formation i n the Selwyn Basin area and hosts s i g n i f i c a n t s t r a t i f o r m l e a d - z i n c - b a r i t e deposits of the MacMillan Pass area. Volcanic t u f f s are int e r c a l a t e d throughout t h i s s ection and are l i k e l y associated with eugeosynclinal conditions developing i n the c e n t r a l Yukon platform at t h i s time (Douglas et a l . , 1970). Regional u p l i f t , centered i n the A r c t i c i s l a n d s area and a t t r i b u t e d to the Ellesmerian Orogeny shed t e r r e s t i a l e l a s t i c s southwards into the Yukon t e r r i t o r y . However, the generally emergent nature of the Mackenzie to O g i l v i e Mountain b e l t at t h i s time 76 r e s t r i c t e d accumulation i n these mountain b e l t s . The incomplete Carboniferous to Permian record r e f l e c t s the emergent nature of the region during the l a t e Paleozoic (Douglas et a l . , i b i d . ) . R e s t r i c t e d areas received t e r r e s t r i a l c l a s t i c sedimentation i n the O g i l v i e and Richardson Mountains. Only minor carbonate rocks formed i n the Mackenzie Mountains during this period. Stable marine Paleozoic sedimentation patterns ceased at t h i s time and were replaced by l o c a l o s c i l l a t o r y marine to non-marine regimes i n the Mesozoic. These were, i n part, induced by the tectonic upheaval which climaxed i n the Columbian Orogeny during Middle J u r a s s i c to l a t e Early Cretaceous (Douglas et a l . , i b i d . ) . U p l i f t , erosion, t i g h t f o l d i n g , thrust f a u l t i n g , and regional metamorphism of argillaceous members dominantly affected the Selwyn Basin region, A ser i e s of small post tectonic quartz monzonite intrusions f r i n g e the Selwyn Basin; potassium-argon dates on the emplacement of these rocks i n d i c a t e a lengthy age span of Middle to Late Cretaceous (110 - 81 m.y.^ Gabrielse, 1967). Potassium-argon dates on syenites and quartz d i o r i t e s intruded i n the Dawson to Mayo area y i e l d a s i m i l a r Late Cretaceous age (76 - 90 m.y., Christopher, 1973; 106 - 110 m.y., Douglas et a l . , 1967). The Columbian mountains were re-juvenated and new mountains were formed during the Laramide Orogeny of l a t e s t Cretaceous to Early Oligocene age. Long arcuate, en echelon f o l d bundles, accompanied by thrusts, comprise the Mackenzie Mountains developed at t h i s time. Many of the f a u l t s and folds followed the traces of older features, however, the sense of movement was often now reversed. Tectonic features such as the Bonnet Plume high, which affected various ages of Paleozoic sedimentation, became less prominent upon rever s a l of the f a u l t s bounding the feature (Norris and Hopkins, 1977). Complex f a u l t movements continued i n t o the Paleocene stage and led to the 77 development of tectonic successor basins such as the Bonnet Plume Basin (Norris and Hopkins, i b i d . ) . 4.3 S t r u c t u r a l Styles Structures of the northern c o r d i l l e r a generally r e f l e c t deformation of supracrustal layered sediments t y p i c a l of the Rocky Mountain b e l t to."the south. In d e t a i l however, a more complex pattern of f o l d s and f a u l t s has been developed i n response to a heterogeneous sequence of rocks and a complex h i s t o r y of rejuvenated tectonic movements. Tectonic elements of the region, prepared by Norris and Hopkins (1977; c . f . King, 1968), are given i n Figure 4-6. En echelon f o l d bundles are evident on the north and west trending sections of the Mackenzie Mountain b e l t , i n the Wernecke Mountains, and through the Northern O g i l v i e Mountains. Extensive thrust f a u l t s are found around the concave i n t e r i o r of the Mackenzie Mountains and extend into the Richardson Mountains. The Columbian orogen, the e f f e c t s of which were centered on the Selwyn Basin area, i s characterized by (1) overturned and thrusted Middle Jurassic and older s t r a t a , (2) pre-middle Cretaceous erosional unconformities, and (3) regional metamorphism of argillaceous sediments (Douglas et a l . , 1970). St r a t i g r a p h i c r e l a t i o n s i n the northwestern part of the basin are p a r t i a l l y obscured due to f o l i a t i o n s associated with northwest trending thrust f a u l t s and i s o c l i n a l f o l d s . Laramide deformation i s d i f f i c u l t to d i f f e r e n t i a t e from Columbian i n areas bordering the Selwyn and Mackenzie f o l d b e l t s . Laramide structures, centered i n the Mackenzie Mountains, exhibit en echelon bundles of broad, short f o l d s and associated f a u l t s . The o f f s e t of the f o l d s i s dex t r a l i n oo FIGURE 4-6: TECTONIC ELEMENTS AND STRUCTURAL TRENDS OF THE NORTHERN CORDILLERA ( a f t e r N o r r i s , 1974; Norris and Hopkins, 1977) 79 the north trending bundles near the Keele River, but i s s i n i s t r a l when the f o l d bundles swing to the west near A r c t i c Red River. Around the nose of the f o l d b e l t , f o l d s are not en echelon, but are of a dip s l i p contraction nature with displacement trending perpendicular to the mean d i r e c t i o n of transport along the f o l d b e l t (Norris, 1974) . Pre-Laramide fracture systems might have been re-activated at t h i s time, and led to the west, northwest, and northeast trending f a u l t s bounding the various f o l d segments (Douglas et a l . , 1970). Norris (1972) prpposed that en echelon f o l d arrays of t h i s nature might develop through slippage of supracrustal rocks over deeper decollement surfaces i n response to p a r a l l e l forces operating i n an opposite sense to each other. It i s most probable that the arcuate nature of the f o l d b e l t was in h e r i t e d p r i m a r i l y from the shape of the ancient miogeocline and the succes-sive depositional elements, however, t h i s pattern might have been s t r u c t u r a l l y accentuated by means of the tectonic movements j u s t described. In the western Mackenzie Mountains, ancient t i g h t l y folded a n t i c l i n e s have been re-folded, and f a u l t e d , often reversing the o r i g i n a l sense of over-turning and hence exposing older u n i t s . Thrust f a u l t s , where they occur, are rather l i m i t e d i n displacement, thereby leading to a c r u s t a l shortening of 10 to 20 percent across the Mackenzie and F r a n k l i n Mountains (Douglas et a l . , 1970). The Richardson An t i c l i n o r i u m (Figure 4-6) i s a broad north trending horst and anticlinorium, plunging gently to the north and dominated by north to northwest:.trending f a u l t s with a large d e x t r a l displacement. . These f a u l t s l i n k up with a s i m i l a r trending f a u l t set of a l e s s conspicuous nature i n the northern Mackenzie Mountains. Major unconformities i n d i c a t e i n t e r m i t -tent movement has been common, elevating some blocks s u f f i c i e n t l y to allow erosion down to the Proterozoic sedimentary rocks, before a r e v e r s a l of the movement allowed the accumulation of much younger material d i r e c t l y on top 80 (e.g. Bonnet Plume Basin: Norris and Hopkins, 1977). Older f a u l t s and anisotropies i n the sedimentary column have aided i n the occurrences of such movements during Columbian and possibly Laramide events. The Taiga Nahoni Fold B e l t (Figure 4-6) includes the O g i l v i e Mountains and forms the westermost re-entrant of the o v e r a l l system. Fold bundles trend westward from the Wernecke Mountains area and swing northwards, approximately along the 140° meridian. The east to west trending arrays are s i n i s t r a l , however, the o f f s e t d i r e c t i o n i s changed on the north trending swing to a de x t r a l sense. Contraction dip s l i p f a u l t s characterize the nose of the arc. The s i m i l a r i t y to the f o l d s t y l e of the arcuate Mackenzie b e l t i s obvious and i s included i n N o r r i s ' (1972) regional en echelon f o l d i n g model. 4.4 Regional Synthesis: P o t e n t i a l f or Strata-bound Zinc-Lead M i n e r a l i z a t i o n The northern c o r d i l l e r a n region appears to be the f i r s t major region within Canada to exhibit geographic and s t r a t i g r a p h i c groupings of carbonate-hosted zinc-lead deposits, hence the name "Mackenzie V a l l e y Pb-Zn D i s t r i c t " has been proposed f o r t h i s area (Sangster and Lancaster, 1976) . This region encompasses the entire Mackenzie V a l l e y watershed and includes the Robb Lake d i s t r i c t i n northeastern B r i t i s h Columbia, the w e l l established Pine Point d i s t r i c t , a South Nahanni d i s t r i c t , and the North Mackenzie Mountain d i s t r i c t . The l a t t e r d i s t r i c t i s the subject of t h i s t h e s i s . Regional inte r p r e t a t i o n s of m i n e r a l i z a t i o n i n the carbonate b e l t of the northern c o r d i l l e r a (Brock, 1976; Macqueen, 1976) are analogous to those proposed by Jackson and Beales (1967) f o r the Pine Point area, and by Heyl (1970) f o r the M i s s i s s i p p i V a l l e y mining d i s t r i c t s . These models involve 81 the expulsion of metal-rich connate brines from argillaceous sediments as they are compacted i n shale basins adjacent to carbonate b e l t s . Igneous thermal a c t i v i t y might be involved i n brine enrichment. Permeable l i t h o l o g i e s or structures provide f l u i d conduits into the carbonate units where p r e c i p -i t a t i o n of sulphides i n s u i t a b l y prepared host rocks i s controlled by physio-chemical f a c t o r s . In the northern c o r d i l l e r a , metals are most l i k e l y derived from i n t e r c a l a t e d shales and volcanic t u f f s of the Selwyn Basin that occur south and west of the mineralized carbonate rocks. Syn-sedimentary l e a d - z i n c -b a r i t e deposits, hosted i n argillaceous sediments of the 'Black C l a s t i c ' u n i t (Figure 4-5) i n the MacMillan Pass area (Dawson, 1977) and i n the shales of the Road River Formation at Howards Pass (Blusson, 1976), lend credence to p o t e n t i a l metal sources being the Selwyn Basin. The a s s o c i a t i o n of this lead, z i n c , and b a r i t e within s p e c i f i c horizons i n the eastern Selwyn Basin suggests l o c a l sedimentary or volcanogenic controls over the m i n e r a l i z a t i o n which i s thought to have occurred during Late Devonian or M i s s i s s i p p i a n time (Dawson, i b i d . ) . Sediment compaction and expulsion of connate f l u i d s from the Selwyn Basin could produce metal-rich brines and thereby constitute a source for the mineralizing s o l u t i o n s . Extensive transport of m i n e r a l i z i n g f l u i d s along regional f a u l t s appears to be an i n t e g r a l part of the model for the formation of the Pine Point ore bodies ( S k a l l , 1975; Kesler e t . a l . , 1972). The dominant d i r e c t i o n of f l u i d migration, as determined from c r y s t a l growth o r i e n t a t i o n studies and elonga-t i o n of ore bodies, has been equated to the trend of a deep, basement f a u l t , the MacDonald f a u l t , which was reactivated during formation of the l i t h o -s t r a t i g r a p h i c hosts for the ore. Secondary dispersion away from t h i s major conduit i s a t t r i b u t e d to migration along the l o c a l j o i n t i n g patterns. Banaszak (1976) has o u t l i n e d s i m i l a r controls over f l u i d migration w i t h i n the Miami trough fracture.zone leading to the M i s s i s s i p p i V a l l e y type 82 m i n e r a l i z a t i o n of the T r i - S t a t e D i s t r i c t - The Upper M i s s i s s i p p i V a l l e y D i s t r i c t and the Southeast Missouri D i s t r i c t also reveal the influences of f o l d s , f a u l t s and j o i n t s over f l u i d migration (Banaszak, i b i d . ; Heyl, 1968). In the northern c o r d i l l e r a , numerous pre-Devonian f a u l t s , unconformities, and permeable c l a s t i c u n i t s provide s u f f i c i e n t aquifers f o r f l u i d s derived from the Selwyn Basin. Fault c o n t r o l l e d m i n e r a l i z a t i o n , i f as dominant as the general descriptions of showings and the petrographic studies i n d i c a t e (Appendix A), suggests that f a u l t s acted as f l u i d conduits which c o l l e c t e d and guided escaping b a s i n a l b r i n e s . C e c i l e and Morrow (1978) proposed that d i f f e r e n t i a l compaction between Road River Formation a r g i l l a c e o u s sediments and overlying porous carbonate units produced fractures which acted as f l u i d migration channels for solutions producing zinc-lead m i n e r a l i z a t i o n i n vugs and veins i n the Mt. Kindle and Delorme Formations. They c i t e the 'black, organic-rich, p y r i t i f e r o u s shales and b a s i c volcanic rocks' of the Road River Formation as the prime metal source ( i b i d . , p. 474), thereby further strengthening the argument for a Selwyn Basin o r i g i n for metal-enriched brines. Facies changes from b a s i n a l shales to platformal carbonates, such as c i t e d by Maucher and Schneider (1967) f o r the Alpine lead-zinc ores, or by Callahan (1967) f o r the M i s s i s s i p p i Valley-type deposits, are also' highly s i g n i f i c a n t i n l o c a l i z i n g t h i s s t y l e of m i n e r a l i z a t i o n . Taylor et a l . (1975) point out that Lower to Middle Devonian dolomitic s i l t s t o n e s and shales form a sharp re-entrant into the carbonate platform at Robb Lake i n north-eastern B r i t i s h Columbia and that this l i k e l y had a strong influence i n l o c a l i z i n g zinc-lead m i n e r a l i z a t i o n present there. This r e l a t i o n s h i p between fa c i e s changes and m i n e r a l i z a t i o n has been noted i n the northern c o r d i l l e r a and has been treated as a major exploration c r i t e r i a (Brock, 1976). Cecil e (1978b) outlined the a s s o c i a t i o n of zinc-lead deposits hosted i n Lower 83 Cambrian Sekwi Formation and Ordovician to S i l u r i a n Mt. Kindle Formation carbonates peripheral to a s i g n i f i c a n t shale re-entrant (the Misty Creek Embayment; Figures 4-4 and 4-5) into the carbonate platform i n the Mackenzie Mountains. The time-space pro j e c t i o n drawn f o r the northern c o r d i l l e r a (Figure 4-5) h i g h l i g h t s - t h e s p a t i a l r e l a t i o n s h i p of the Selwyn Basin shale f a c i e s and zinc-lead m i n e r a l i z a t i o n hosted i n carbonates of Ordovician to Devonian age. Many of the regional features pertinent to the model of b a s i n a l s t r a t a -f u g i c solutions leading to m i n e r a l i z a t i o n i n the adjacent carbonate b e l t are present i n the northern c o r d i l l e r a ; hence, t h i s model appears r e a d i l y a p p l i c a b l e to t h i s area. However, zinc-lead m i n e r a l i z a t i o n a t t r i b u t a b l e to a process of k a r s t i f i c a t i o n of the carbonate b e l t adjacent to major uncon-formities i s also a v a l i d consideration for the northern c o r d i l l e r a . Figures 4-4 and 4-5 indicate the existence of major regional unconform-i t i e s within and overlying carbonate u n i t s of Proterozoic and Lower Cambrian age. Unconformities can be important as f l u i d conduits; however, they might also be r e l a t e d to paleokarst features and therefore to preparation of a host for zinc-lead m i n e r a l i z a t i o n (Callahan, 1967; Olson, 1977) . C o l l i n s and Smith (1972) studied the r e l a t i o n between tectonic movements and k a r s t i f i c a -t i o n over zinc-lead m i n e r a l i z a t i o n i n Newfoundland and concluded that ". . . there i s an inherent i n e v i t a b i l i t y to s p h a l e r i t e m i n e r a l i z a t i o n given a carbonate platform undergoing a l a t e major depositional phase followed by a major ero s i o n a l phase" ( i b i d . , p. 215). Paleokarst development enhanced permeability i n f l u i d conduits and provided depositional s i t e s f o r m i n e r a l i -z a t i o n i n the Pine Point ore bodies ( S k a l l , 1975) . Brock (1976) records that s o l u t i o n b r e c c i a t i o n , as a r e s u l t of k a r s t i f i c a t i o n r e l a t e d to overlying unconformities, l o c a l i z e d some of the m i n e r a l i z a t i o n at the Gayna River deposit (number 20024) i n the northern c o r d i l l e r a , and possibly also c o n t r o l l e d f 84 m i n e r a l i z a t i o n i n the Goz Creek (number 10033) and Bear (number 20012) deposits. The diagrammatic cross-section f o r the Mackenzie Mountains (Figure 4-4) displays the extent of the sub-Upper Cambrian unconformity and h i g h l i g h t s the p o s s i b i l i t y of groundwater solutions draining o f f the Mackenzie Arch and through the adjacent Proterozoic and Lower Cambrian carbonates during regional u p l i f t and exposure of the area i n Middle to Upper Cambrian time. Therefore, the regional stratigraphy and geologic h i s t o r y of the northern c o r d i l l e r a contains numerous elements important to the development of stratabound carbonate hosted zinc-lead m i n e r a l i z a t i o n . A purely s t r a t i -graphic approach can be taken, as has been done i n the Pine Point area to the southeast ( S k a l l , 1975) or i n the Robb Lake area to the south (Taylor et a l . , 1975) . 85 CHAPTER 5: MINOR ELEMENTS IN S PHALERITE FROM THE NORTHERN YUKON AND ADJACENT DISTRICT OF MACKENZIE 5.1 Geological C h a r a c t e r i s t i c s of Sphalerite Occurrences i n the Northern  C o r d i l l e r a The s i g n i f i c a n c e of the s t r a t i g r a p h i c and s t r u c t u r a l framework of the northern c o r d i l l e r a , r e l a t i v e to the metallogeny of the region, i s , at present, not f u l l y understood. This r e l a t i o n s h i p can be of prime importance i n defining controls on mine r a l i z a t i o n , as has been shown i n established mining areas such as the southeastern Missouri lead-zinc d i s t r i c t (Gerdemann and Myers, 1972) or the Pine Point d i s t r i c t ( S k a l l , 1975) . Therefore, a summary d e s c r i p t i o n of the nature of the geologic occurrence of the s p h a l e r i t e deposits considered i n t h i s study follows, based on 1) b r i e f geologic data supplied with the samples, 2) the mineralographic character of the a v a i l a b l e samples, and 3) general descriptions published to date on a few deposits (e.g. Brock, 1976). This summary provides a broader data base f o r l a t e r i n t e r p r e t a t i o n of the a n a l y t i c a l r e s u l t s .in terms of regional metallogenesis. Locations of the 48 deposits studied are displayed on the index map i n Figure 5-1 and t h e i r geographic and basic geologic d e t a i l s are summarized i n Table 5-1. Included on the index map are a further 44 points s p e c i f y i n g the locations of s i m i l a r m i n e r a l i z a t i o n within the same b e l t of rocks; samples from these a d d i t i o n a l 44 showings, although a v a i l a b l e for study, were rejected because they were unsuitable f o r pure separation of s p h a l e r i t e grains . The main trend of these 92 locations follows the arcuate trace of the Backbone Ranges of the Mackenzie Mountains but the d i s t r i b u t i o n of deposits becomes more dispersed to the northwest i n the Wernecke Mountains (Figure 5-1) . Another trend of deposits r e f l e c t s the b e l t of disturbed carbonate rocks of oo ON FIGURE 5-1: INDEX MAP OF ZINC-LEAD DEPOSITS•STUDIED Numbered locatio n s ( »06) represent occurrences of sph a l e r i t e analyzed i n this report; a l l Yukon deposits are prefixed by 100; a l l N.W.T. deposits are prefixed by 200 (see Table 5-1). Unnumbered locatio n s (* ) represent occurrences of s p h a l e r i t e present i n the specimen c o l l e c t i o n but not analyzed. 87 T A B L E 5 - 1 G E O G R A P H I C A N D G E O L O G I C I N F O R M A T I O N F C R 1 6 6 S P E C I M E N S S T U D I E D ID.NO. N A M E N T S L A T L O N G H O S T L I T H . H O S T A G E C O M M O D I T I E S 1 0 C 0 6 0 0 2 N E W T 1 0 6 D U 6 4 . 5 3 1 3 5 . 4 7 O O L M 8 R X X O R D - S I L Z N P B 1 0 C 0 6 C C 3 N P W T 1 0 6 0 1 1 6 4 . 5 3 1 3 5 . 4 7 D O L M R R X X O R D - S I L Z N P R 1 0 C 0 6 0 O 5 M r W T 1 0 6 0 U 6 4 . 5 3 1 3 5 . 4 7 D O L M R R X X O R D - S I L Z N P B 1 C C 1 0 C 0 1 E C O N O M I C 1 0 6 3 0 6 6 4 . 3 3 1 3 1 . 2 2 D O L M I V M ) i;w C A M S P 3 Z N 1 C C 2 0 0 0 4 T A R T 1 1 6 3 1 3 6 4 . 8 3 1 3 9 . 8 3 O O L M RRXX H E L I K 1 A N P 3 Z N 1 0 0 2 2 0 0 4 W I L L 1 0 S 0 C 7 6 4 . 4 0 1 3 4 . 7 C D C L M B R X X H E L I K I A N P B Z N C U 1 0 0 2 4 0 0 1 C O M I N C O A - 6 1 0 6 C 1 0 6 4 . 7 5 1 3 2 . 9 5 O O L M B R X X H A D R Y N I A N P 3 Z N 1 0 0 2 4 0 0 2 C O M I N C O A + 6 1 0 6 C 1 0 6 4 . 7 5 1 3 2 . 9 5 O O L M R R X X H A D R Y N I A N P B Z N 1 0 0 2 5 0 0 1 C O M I N C O B C + 5 1 0 6 C 1 0 6 4 . 7 0 1 3 2 . 9 5 O O L M B R X X H A D R Y N I A N P B Z N 1 0 0 2 5 0 0 4 C O M I N C O B C - 5 1 0 6 C 1 0 6 4 . 7 0 1 3 2 . 9 5 D O L M R R X X H A D R Y N I A N P B Z N 1 0 0 2 5 0 0 6 C O M I N C O B C * ' 5 1 0 6 C 1 0 6 4 . 7 0 1 3 2 . 9 5 D O L M P R X X H A D R Y N I A N P B Z N 1 0 0 2 6 0 0 1 V U G . 1 1 6 A 0 9 6 4 . 5 7 1 3 6 . 2 3 D O L M B R X X r- E L I K I A N Z N P S 1 C C 2 7 C 0 1 C O M I N C O 7 * 0 1 0 6 C 1 1 6 4 . 6 2 1 3 3 . 2 5 D C L M R R X X H A D R Y N I A N P B Z N 1 0 0 2 7 0 0 2 C O M I N C O 7 + r> 1 0 6 C 1 1 6 4 . 6 2 1 3 3 . 2 5 D O L M B R X X H A D R Y N I A N P B Z N 1 0 C 2 7 C C 3 C O M I N C O 7 - 0 T 0 6 C 1 1 6 4 . 6 2 1 3 3 . 2 5 D O L M BRXX H A CR Y N I A N P B Z N 1 0 0 2 7 0 0 4 C O M I M C O 7 + D 1 0 6 C 1 1 6 4 . 6 2 1 3 3 . 2 5 D C L M R R 0 X X H A CR Y N I A N P B Z N I 0 0 2 7 C 0 5 C O M I N C O 7 + D 1 0 6 C 1 1 6 4 . 6 2 1 3 3 . 2 5 D O L M B R X X H A D R Y N I A N PR Z N 1 0 0 2 6 0 C 3 C C M I N C O 1 1 0 6 C 1 0 6 4 . 5 3 1 3 2 . 5 8 D C L M B R X X S I L - O E V ° B Z N 1 0 0 2 8 0 0 7 C O M I N C O 1 1 0 6 C 1 0 6 4 . 5 8 1 3 2 . 5 8 D O L M B R X X S I L r - D E V P O Z N 1 0 0 2 9 0 0 2 T O P O P D W S K I 1 0 6 C 1 0 6 4 . 7 0 1 3 2 . 6 5 L I " S C O N G S I L - D E V P B Z N 1 0 C 2 9 C 0 4 ' ' T O ° O P O W S K I . 1 0 6 C 1 0 6 4 . 7 0 1 3 2 . 6 5 L I M S C O N G S I L - D E V P B Z N 1 0 0 2 9 0 0 5 T O P O R O . V S K I 1 0 6 C 1 0 6 4 . 7 0 1 3 2 . 6 5 L I M S C O N G S I L - O E V P B Z N 1 0 C 2 9 0 0 8 T O P O R O V S K l 1 0 6 C 1 0 6 4 . 7 0 1 3 2 . 6 5 L I M S C O N G S I L - D E V P B Z N 1 0 0 3 0 0 0 1 C O ^ I N C O 3 1 0 6 C C 5 6 4 . 5 0 1 3 3 . 8 3 D O L M H E L I K I AN P 3 Z N 1 0 C 3 2 0 0 1 C L O E 1 0 6 E 0 2 6 5 . 2 0 1 3 4 . 7 0 S H A L B R X X H E L I K I A N Z N P B 1 0 0 3 3 0 C 1 ooz 1 0 6 C C 7 6 4 . 4 3 1 3 2 . 5 5 O C L M B R X X L C H C A M S Z N 03 C D A G 1 0 0 3 3 0 0 4 G O I 1 0 6 C . 0 7 6 4 . 4 3 1 3 2 . 5 5 D O L M 5 R X X L O W C A M 3 Z N P 3 C D A G 1 0 0 3 3 0 0 5 G O Z 1 0 6 C 0 7 6 4 . 4 3 1 3 2 . 5 5 D O L M B R X X L O W C A M R Z N P B C D A C , 1 0 0 3 3 0 1 2 G O Z 1 0 6 C C 7 6 4 . 4 3 1 3 2 . 5 5 O O L M B R X X L O W C A M 3 Z N P 3 C D A C . 1 0 0 3 3 0 1 3 G O 7. 1 0 6 C 0 7 6 4 . 4 3 1 3 2 . 5 5 D O L M B R X X L O W C A M B Z N ° B C D A G 1 0 0 3 3 0 1 4 G O Z 1 0 6 C 0 7 6 4 . 4 3 1 3 2 . 5 5 O C L M B R X X L O W C A M B Z N P B C O A G 1 C C 3 3 0 1 5 G O Z 1 0 6 C 0 7 6 4 . 4 3 1 3 2 . 5 5 D O L M R R X X L O W C A M R Z N P B C D A G 1 0 0 3 3 0 1 6 G O Z 1 0 6 C 0 7 6 4 . 4 3 1 3 2 . 5 5 O C L M B R X X L O W C A M R Z N =>B C D A G 1 0 0 3 3 C 1 7 G O Z 1 0 6 C C 7 6 4 . 4 3 1 3 2 . 5 5 D C L M B R X X L O W C A M B Z N P 3 C O A G 1 0 0 3 3 0 2 1 G O Z 1 0 6 C 0 7 6 4 . 4 3 1 3 2 . 5 5 D C L M B R X X L O W C A M B Z N P B C D A G 1 0 0 3 3 0 2 2 0 0 z 5 . 0 6 C 0 7 6 4 . 4 3 1 3 2 . 5 5 D O L « B R X X L O W C A M B • Z N P B C D A G 1 0 0 3 3 0 2 3 G O Z 1 0 6 C C 7 6 4 . 4 3 1 3 2 . 5 5 D O L M B R X X L C W C A M 3 Z N P 3 C O A G 1 0 0 3 3 0 2 4 G O Z 10 6C 0 7 6 4 . 4 3 1 3 2 . 5 5 0 0 L « B R X X L O W C A M B Z N P B C D A G 1 0 0 3 3 0 2 5 G O Z S O 6 C 0 7 6 4 . 4 3 1 3 2 . 5 5 O O L M B R X X L O W C A M B Z N P B C D A G 1 C 0 3 4 0 0 1 3 1 R K E L A N D 1 0 6 B C 4 6 4 . 1 5 1 3 1 . 9 2 D O L M R R X X H A D R Y N I A N Z N P 3 1 0 0 3 4 0 C 2 8 1 D K E L A N D 1 0 6 B O 4 6 4 . 1 5 1 3 1 . 9 2 D O L M B R X X H A D R Y N I A N Z N P B 1 0 C 3 4 0 C 9 B I R K E L A N O 1 0 6 3 0 4 6 4 . 1 5 1 3 1 . 9 2 D O L M B R X X H A D R Y N T A N Z N (>8 1 0 C 3 5 0 0 1 C O M I N C O 8 1 O 6 L 0 6 6 6 . 3 3 1 3 5 . 5 2 D O L M R R X X C A M 3 R ! A N P B Z N 1 0 C 3 5 0 0 2 C O M I N C O 8 1 0 6 L C 6 6 6 . 3 3 1 3 5 . 5 2 D O L M B R X X C A M R R I A N PR Z N 1 C C 3 6 0 0 1 C O M I N C O 9 1 0 6 C 1 4 6 4 . 9 7 1 3 3 . 2 0 D C L M R R X X H E L I K I A N P B Z N 1 0 0 3 6 0 0 2 C O M I N C O 9 1 0 6 C 1 4 6 4 . 9 7 1 3 3 . 2 0 O O L M B R X X H E L I K I A N P B Z N 1 0 0 3 7 0 0 3 O Z 1 1 6 B 1 2 6 4 . 7 5 1 3 9 . 7 5 D C L M R R X X F F L I K I A N P B Z N 1 0 0 3 7 0 0 4 O Z 1 1 6 B 1 2 6 4 . 7 5 1 3 9 . 7 5 D O L M R R X X H E L I K I A N P B ZN 1 0 0 3 7 0 2 0 O Z 1 1 6 3 1 2 6 4 . 7 5 1 3 9 . 7 5 O O L M B R X X H E L I K I A N P B Z N 1 0 0 3 7 0 2 8 OZ 1 1 6 3 1 2 6 4 . 7 5 1 3 9 . 7 5 D C L M B R X X H E L I K I A N P B Z N 1 0 0 3 7 0 3 0 O Z U 6 B 1 2 6 4 . 7 5 1 3 9 . 7 5 D O L M B R X X H E L I K I A N P B Z N 1 0 0 3 7 0 3 1 O Z U 6 3 1 2 6 4 . 7 5 1 3 9 . 7 5 D O L M B R X X F F L I K I A N P B Z N 1 0 0 3 7 0 3 2 nz 1 1 6 3 1 2 6 4 . 7 5 1 3 9 . 7 5 O O L M B R X X h E L I K I A N P B Z N 1 0 C 4 2 0 0 1 P P O . F E IT 1 0 6 C 1 4 6 4 . 3 2 1 3 3 . 5 5 D O L M B R X X H A D R Y N I A N P B Z N A G B A C U 1 0 C 4 2 O O 2 P R O F E I T 1 0 6 C 1 4 6 4 . 3 2 1 3 3 . 5 5 O O L M B R X X H A D R Y N I A N P B Z N B A C U 1 G C 4 2 0 0 3 P R O F E I T 1 0 6 C 1 4 6 4 . 3 2 1 3 . 3 . 5 5 D D L " R R X X H A D R Y N I A N P B Z N A G B A CU 1 0 0 4 2 0 0 4 P R O F E I T I . 0 6 C 1 4 6 4 . 3 2 1 3 3 . 5 5 O O L M RRXX H A D R Y N I A N P S Z N A G B A C U 1 0 0 4 2 C C 8 P R O F E I T 1 0 6 C 1 4 6 4 . 8 2 1 3 3 . 5 5 D C L M B R X X H A D R Y N I A N P B Z N A G B A C U 1 0 0 4 2 0 0 9 P R O F E I T K J 6 C 1 4 6 4 . 8 2 1 3 3 . 5 5 D O L M B R X X H A D R Y N I A N P B Z N A G B A C U 1 0 0 4 2 0 1 0 P R O F E I T M 6 C 1 4 6 4 . 3 2 1 3 3 . 5 5 O O L M B R X X H A D R Y N I A N P B Z N A G B A C U 1 0 0 4 2 0 1 1 P O O F E I T 1 0 6 C 1 4 6 4 . 8 2 1 3 3 . 5 5 D C L M BRXX H A D R Y N I A N P B Z N A G B A cu 1 0 0 4 2 0 1 5 P R O F E I T 1 E 6 C 1 4 6 4 . S 2 1 3 3 . 5 5 O C L M R R X X H A C R Y N I A N P B Z N A G B A C U 1 C C 4 2 0 1 9 P R O F E I T 1 0 6 C 1 4 6 4 . 8 2 1 3 3 . 5 5 D O L M BRXX H A D R Y N I A N P B Z N A G B A C U 1 0 0 4 2 0 2 3 P R O F E I T 1 0 6C 1 4 6 4 . 3 2 1 3 3 . 5 5 D O L M B R X X H A C R Y N I A N P B Z N A G B A cu 1 0 0 4 2 0 2 7 P R O F E I T 1 0 6 C 1 4 6 4 . 3 2 1 3 3 . 5 5 D O L M R R X X H A D R Y N I A N P S Z N A G 6 A cu 1 0 0 4 2 0 3 1 P R O F E I T 1 0 6 C 1 4 6 4 . 8 2 1 3 3 . 5 5 D C L M R R X X H A C R Y N I A N P 3 I N A G B A cu 1 0 0 4 2 0 3 6 P R O F E I T I 0 6 C 1 4 6 4 . 8 2 1 3 3 . 5 5 D O L M B R X X H A D R Y N I A N P 3 Z N A G RA cu 1 0 0 4 2 0 4 0 P R O F E I T I 0 6 C 1 4 - 6 4 . 8 2 1 3 3 . 5 5 D C L M B R X X H A D R Y N I A N P B Z N A G B A cu 1 0 0 4 2 0 4 1 P R O F E I T 1 0 6 C 1 4 6 4 . 8 2 1 3 3 . 5 5 D O L M B R X X H A D R Y N I A N P B Z N A G 3 A cu 1 0 0 4 2 0 4 2 P R O F E I T 1 0 6 C 1 4 6 4 . 8 2 1 3 3 . 5 5 D O L M B R X X H A D R Y N I A N P B Z N AG B A cu 1 C 0 4 2 0 4 3 P R O F E I T 1 0 6 C 1 4 6 4 . 8 2 1 3 3 . 5 5 D O L M B R XX H A C R Y N I A N P B Z N A G B A cu 88 T A B L E 5 - 1 ( C O N T I N U E D * T O . N O . N A M E N T S L A T L O N G H O S T L I T H . H O S T A G E C O M M O D I T I E S 1 0 0 4 3 0 0 4 F I S H I N G 3 R O H 1 1 6 J 0 5 E 1 0 0 4 3 0 0 5 F I S H I N G 3 R C H 1 1 6 J C 5 E 1 C 0 4 4 0 0 1 W A R T 1 1 6 J 0 3 W 1 0 0 4 5 0 0 1 A X E 1 0 6 C 1 0 E 1 C 0 4 6 0 0 1 G E 8 / 1 9 / 7 5 1 0 6 3 G 4 E 1 C C 4 6 0 C 2 G E 8 / 1 9 / 7 5 1 0 6 3 C 4 E 1 C 0 5 0 0 0 1 0 0 0 1 0 5 O 1 3 W 1 0 C 5 3 O O 1 M T T I L L I C U M 1 0 6 C C 2 W 2 C C C 3 0 C 4 P A L M 1 0 6 A C 5 2 0 0 0 3 0 0 5 P A L M 1 O 6 A 0 5 2 C C 0 4 0 0 1 J U D E I 0 6 A C 5 2 0 C 0 4 0 0 2 J U D E 1 0 6 A C 5 2 0 C 0 4 0 0 3 J U O E 1 0 6 A C 5 2 C O 0 5 0 0 1 S I S C O E 1 0 6 3 G 1 2 0 0 0 5 0 0 4 S I S C O E 1 0 6 R 0 1 2 0 0 0 6 0 0 1 P A M 1 0 5 D U 2 C C 0 6 C C 5 P A M 1 0 5 P 1 1 2 0 0 0 6 0 0 4 P A M 1 0 5 P 1 1 2 C C C 8 C C 7 B A C K B O N E 1 0 5 P 1 4 2 C C 0 8 C 0 9 B A C K B O N E 1 0 5 P 1 4 2 C 0 0 9 C 0 4 W E A T H E R 1 0 5 P 1 4 2 C C 1 2 0 0 1 T W I T Y A 1 C 6 A C 3 2 0 0 1 2 0 0 2 T W I T Y A 1 0 6 A 0 3 2 0 0 1 2 0 0 3 T W ! T Y A 1 0 6 A 0 3 2 0 0 1 2 0 0 4 T W I T Y A 1 0 6 A C 3 2 0 C 1 2 0 0 5 T W I T Y A 1 0 6 A C 3 2 0 C 1 2 O O 6 T W I T Y A 1 0 6 A 0 3 2 0 C 1 2 C C 7 T W I T Y A 1 0 6 A 0 3 2 C 0 1 2 0 0 8 T W I T Y A 1 0 6 A 0 3 2 C C 1 2 0 1 0 T W I T Y A 1 0 6 A C 3 2 0 0 1 2 0 1 1 T W I T Y A 1 1 0 6 A 0 3 2 0 C 1 2 0 1 3 T W I T Y A 1 0 6 A 0 3 2 C 0 1 3 0 0 1 E S S A U 1 0 6 3 1 5 2 0 0 1 5 0 0 4 J I M 1 0 6 B 0 8 2 C C 1 9 0 0 * G I L O F R S L E E V E 1 0 6 C 1 6 2 0 0 2 0 0 0 3 M O G U L 1 0 6 C 1 6 2 C 0 2 1 0 0 1 F C C L A I M S 1 0 S B C S 2 0 0 2 1 C 0 2 F C C L A I M S 1 C 6 3 C 8 2 0 C 2 3 0 1 0 P. E V 1 0 6 A 0 3 2 G 0 2 3 0 2 4 R E V 1 O 6 A 0 3 2 C 0 2 3 0 5 5 R E V I 0 6 A C 3 2 0 0 2 3 0 6 0 R E V W 6 A C 3 2 0 0 2 3 0 6 1 R E V 1 0 6 A 0 3 2 0 0 2 3 0 9 6 •3 C V 1 0 6 A C 3 2 0 0 2 3 C 9 7 R E V 1 0 6 A 0 3 2 C C 2 3 1 2 6 R E V 1 G 6 A C 3 2 0 0 2 3 1 2 7 R E V 1 0 6 A 0 3 2 C C 2 3 1 2 8 R E V 1 0 6 A C 3 2 0 0 2 3 1 2 9 R E V 1 0 6 A 0 3 2 0 0 2 3 1 3 6 R E V 1 0 6 A C 3 2 0 0 2 3 1 3 8 R E V 1 0 6 A 0 3 2 0 0 2 3 1 4 0 R E V 1 0 6 A 0 3 2 0 0 2 3 1 4 1 P E V 1 0 6 A 0 3 2 0 0 2 3 1 4 2 R E V 1 0 6 A 0 3 2 0 0 2 3 1 A 4 R E V 1 0 6 A G 3 2 0 C 2 3 1 5 3 R E V 1 0 6 A 0 3 2 0 0 2 3 1 5 4 R E V 1 0 6 A C 3 2 0 0 2 3 1 5 5 R E V 1 0 6 A 0 3 2 0 0 2 4 0 0 1 O A Y N A 1 0 6 3 1 5 2 0 0 2 4 0 0 3 G A Y \ J A 1 0 6 B 1 5 2 0 0 2 4 0 0 5 G A Y N A 1 0 6 F U 5 2 0 C 2 4 C C 7 G A Y N A 1 0 6 9 1 5 2 0 0 2 4 0 0 8 G A Y N A 1 0 6 3 1 5 2 0 C 2 4 0 1 1 G A Y N A 1 0 6 . 3 1 5 2 0 0 2 5 0 0 1 T E G A R T 1 0 6 R C 9 2 0 0 2 5 0 0 2 T E G A R T 1 C 6 3 C 9 2 C 0 2 5 O 0 3 T E G A R T S O 6 6 0 9 2 0 0 2 5 0 0 5 T E G A R T 1 0 6 3 C 9 2 0 0 2 5 0 0 6 T E G A R T 1 0 6 3 0 9 2 0 0 2 5 0 1 C T E G A R T 1 0 6 B C 9 2 0 0 2 5 0 1 1 T E G A R T 0 6 3 C 9 2 0 C 2 5 0 1 2 T E G A R T 0 6 B C 9 6 6 . 6 6 . 6 6 . 6 4 . 6 4 . 6 4 . 6 3 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 3 . 6 3 . 6 3 . 6 3 . 6 3 . 6 3 . 6 4 . 6 4 . 6 4 . 6 4 . 6 ' . . 6 4 . . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 . 6 4 6 4 6 4 6 4 6 4 6 4 6 4 6 4 6 4 6 4 6 4 6 4 3 3 1 3 9 . 6 7 3 3 1 3 9 . 6 7 0 7 1 3 9 . 4 7 5 6 1 3 2 . 5 8 2 5 1 3 1 . 3 1 2 5 1 3 1 . 3 1 9 1 1 3 2 . 0 0 4 2 1 3 2 . 8 6 4 0 1 2 9 . 3 0 4 0 1 2 S . 3 0 3 7 1 2 9 . 8 7 3 7 1 2 9 . 8 7 3 7 1 2 9 . 8 7 1 8 1 3 0 . 3 8 1 3 1 3 0 . 3 8 5 2 1 2 9 . 1 2 5 2 1 2 9 . 1 2 5 2 1 2 9 . 1 2 8 5 1 2 9 . 1 7 8 5 1 2 9 . 1 7 9 7 1 2 9 . 2 8 0 3 1 2 9 . 3 7 0 3 1 2 9 . 3 7 0 3 1 2 9 . 3 7 0 3 1 2 9 . 3 7 0 3 1 2 9 . 3 7 0 3 1 2 9 . 3 7 0 3 1 2 9 . 3 7 0 3 1 2 9 . 3 7 . 0 3 1 2 9 . 3 7 , 0 3 1 2 9 . 3 7 . 0 3 1 2 9 . 3 7 . 7 5 1 3 0 . 5 3 . 4 8 1 3 0 . 4 5 . 9 8 1 3 2 . 4 5 . 9 8 1 3 2 . 3 0 . 3 6 1 3 0 . 2 0 . 3 6 1 3 0 . 2 0 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 1 3 1 2 9 . 3 3 . 9 5 1 3 0 . 7 0 . 9 5 1 3 0 . 7 0 . 9 5 1 3 0 . 7 0 . 9 5 1 3 0 . 7 0 . 9 5 1 3 0 . 7 0 . 9 5 1 3 0 . 7 C . 5 3 1 3 0 . 1 7 . 5 3 1 3 0 . 1 7 . 5 3 1 3 0 . 1 7 . 5 3 1 3 0 . 1 7 . 5 3 1 3 C . 1 7 . 5 3 1 3 0 . 1 7 . 5 3 1 3 0 . 1 7 . 5 3 1 3 0 . 1 7 O C L M D O L M O O L M D O L M D O L M D C L M O C L M O O L M D O L M O O L M O C L M D C L M D O L M L C S T L M S T D C L M D O L M D C L M L M S T L M S T D O L M D O L M D O L M D O L M D O L M D O L M D O L M D O L M D O L M D O L M D C L M D O L M L I M S O C L M D C L M D O L M D C L M D O L M D O L M O O L M D C L M D O L M D O L M D C I M D O L M D O L M D O L M D C L M D C L M O O L M D O L M D O L M D C L M D C L M D C L M D C L M D C L M D O L M D O L M D O L M D O L M O C L M D O L M 0 0 1 M D C L M D O L M D O L M D O L M D O L M D C L M D O L M D O L M B R X X R R X X B K X X B R X X ( V N ) 3 P X X B R X X 3 K X X e?xx B R X X B K X X B R X X R R X X BR X X PR X X B R X X BR X X B R X X B R X X R R X X B R X X B R X X E R X X P R X X B R X X B R X X B R X X eRxx B R X X R R X X B R X X B R X X ( V M ( V M I I V M ( V M I ( V N ) ( V M ( V N ) ( V M ( V N ) ( V M ( V N ) ( V N ) ( V N I I V M < V N ) ( V N I ( V N I ( V N ) ( V N ) I V N ) B R X X B R X X B R X X E R X X B R X X B R X X B R X X B R X X B R X X B R X X B R X X E P X X B R X X B R X X O R D - S I L O R D - S I L O R D - S R L S I L - D E V C A M R R I A N C A M 3 R I A.N H A OR Y N I A . N H A C R Y N I A M L C W C A M B L O W C A MB O P O - S I L C R D - S I L O R D - S I L D F V O N I A N D E V O N I A N L C W C A M Q L O W C A M S L O W C A M ? D E V O N I A N D E V O N I A N D E V O N I A N S I L - D E V S I L . - D E V S I L - D E V S I L - D E V S I L - D E V S I L - D E V S I L - D E V S I L - D E 7 S I L - D E V S I L - D E V S I L - D E V H A CR Y N I A N D E V O N I A N L C W C A M 3 L O W C A M S D E V O N I A N D E V O N I A N O R O - S ! L C R D - S I L C R D - S I L O R D - S I L O P O - S I L O R D - S ! L O R D - S I L O P C - S I L O R D - S I L O P O - S I L O R O - S I L O R D - S I L C R D - S I L O R D - S I L C R D - S I L O R C - S I L C R D - S I L C R D - S I L O R D - S I L O R D - S I L H E L I K I A N H E L I K I A N H E L I K I A N I - E L I K I A N H E L I K I A N H E L I K I A N O R D - S I L O F O - S I L O R D - S I L O R C - S I L O R D - S I L O P C - S I L O R D - S I L O R D - S I L Z N P S Z N P 3 Z N P 3 Z N P 3 P 3 Z N P S Z N Z N Z N P 3 Z N P B Z N P S Z N Pi Z N P S Z N P 3 Z N P B Z N P B P B Z N P B Z N P B Z N Z N P B B A Z N P B 3 A Z N P B Z N P 3 A G Z N P B A G Z N P B A G 7 N P B A G Z N P B A G Z N P 3 A G Z N P S A G Z N P B A G Z N P S A G Z N P S A G Z N P S A G Z N P B A G Z N P S A G Z N P B A G Z N P 3 Z N 3 A P B Z N B A P B Z N P B Z N P 3 Z N P B Z N P B Z N P 3 Z N P B Z N P B Z N P B Z N P S Z N P 3 Z N P S Z N P 9 Z N P 8 Z N P S Z N P B Z N P S Z N P S Z N P 3 Z N P B Z N P B Z N C D P B Z N C O P B Z N C O P B Z N C C P B Z N C D P B Z N C D P B Z N P 3 Z N O B Z N . P B Z N P B Z N P B Z N P S Z N P B Z N P S 89 T A B L ( C O N T 1 0 . N O . N A M E N T S L A T 2 0 0 2 7 C 0 3 C L f A X 1 0 5 ° C 8 6 3 . 3 5 2 0 0 2 7 0 0 4 C L I M A X 1 0 5 P 0 8 6 3 . 3 5 2 0 0 3 2 0 0 1 M N T N R I V E R 1 0 6 R O O E 6 4 . 3 3 2 C 0 3 4 0 0 1 KI N O 1 0 6 A C 8 6 4 . 3 7 2 0 C 3 4 0 0 2 K I N O 1 0 6 A 0 8 6 4 . 3 7 2 0 0 3 4 0 0 3 K I N D 1 C 6 A C 8 6 4 . 3 7 2 0 0 3 4 0 0 5 K I N D 1 0 6 A 0 8 6 4 . 3 7 2 0 0 3 4 0 1 1 K I N D 1 0 6 A C 8 6 4 . 3 7 2 0 0 3 5 0 0 1 S E R F M 1 0 6 R 0 8 E 6 4 . 4 0 2 0 C 3 5 0 0 2 S E P E M 1 0 6 R C 8 E 6 4 . 4 0 2 0 0 3 5 0 0 3 S E » ~ M 1 0 6 3 C 8 E 6 4 . 4 0 2 0 0 3 5 0 0 6 S E R E M 1 0 6 3 C 8 E 6 4 . 4 0 2 C C 3 6 0 0 1 K W I 1 0 6 R 0 9 E 6 4 . 6 1 2 0 0 3 6 0 0 3 K W I 1 0 6 3 O S E 6 4 . 6 1 2 0 C 3 6 C 0 5 K W ! 1 0 6 R 0 9 E 6 4 . 6 1 2 C 0 3 6 C C 6 K W I 1 0 6 R C S E 6 4 . 6 1 2 C 0 3 7 0 0 1 G J 7 / 3 0 / 7 5 1 0 6 R 0 8 E 6 4 . 4 0 2 C C 3 7 0 0 2 G J 7 / 3 0 / 7 5 1 0 6 S C 8 E 6 4 . 4 0 2 C 0 3 S 0 0 1 G J 7 / 1 4 / 7 5 1 0 6 A C 5 W 6 4 . 4 0 2 0 0 3 9 0 0 1 G U N 1 0 5 I 1 5 E 6 2 . 8 8 2 C C 4 0 0 0 1 G J 7 / 2 7 / 7 5 1 0 6 3 C 9 E 6 4 . 4 2 2 0 0 4 0 0 0 2 G J 7 / 2 7 / 7 5 1 0 6 8 0 9 E 6 4 . 4 2 2 C C 4 0 0 0 3 G J 7 / 2 7 / 7 5 1 0 6 8 0 9 E 6 4 . 4 2 E 5 - 1 I N U E O t L O N G H O S T L I T H . H O S T A G E C O M M O D I T I E S —*—— 1 2 8 . 3 8 O C L M H A O R Y N I A N ZN O R 1 2 8 . 3 3 D O L M H A O R Y M I A N ZN P B 1 3 0 . 1 0 D C L M B R X X S I L - D E V ZN P 3 1 2 9 . 7 3 D O L M R R X X O R D - S I L ZN P 3 1 2 9 . 7 3 D O L M BRXX O R D - S I L ZN ° 8 1 2 9 . 7 3 D C L M BRXX O R D - S I L ZN P B 1 2 9 . 7 3 D O L M B R X X O R D - S I L Z N P 3 1 2 9 . 7 3 D C L M BRXX O P D - S I L ZN P B 1 3 0 . 1 3 DCLM. B R X X O R D - S I L ZN P B 1 3 0 . 1 3 D O L " B R X X O R O - S I L ZN P 9 1 3 0 . 1 3 O C L M B R X X C R D - S I L ZN » R 13 0 . 1 3 D O L M B R X X O R D - S I L Z N P B 1 3 0 . 0 3 ' D O L « B R X X L O W C A M ZN P B 1 3 0 . 0 3 D C L M BRXX I C HC A M ZN P 9 1 3 C . 0 3 D O L M B R X X L Q W C A M Z N P B 1 3 0 . 0 3 D C L M PRXX L C W C A M ZN P 8 1 3 0 . 2 5 D O L M R R X X D E V O N I AN Z N 1 3 0 . 2 5 D O L M BRXX D E V O N I A N ZN 1 2 9 . 8 0 D O L M B R X X O R D - S I L ZN 1 2 8 . 5 5 L IMS C A M R R I A N Z N B A 1 3 0 . 2 0 D C L M BRXX O R D - S I L P B Z N 1 3 0 . 2 0 D O L M R R X X O R D - S I L PB Z N 1 3 0 . 2 0 D O L M 3 R X X O R D - S I L " P 3 Z N 90 the O g i l v i e Mountains and t h e i r northward extension into the Northern O g i l v i e Mountains (Figure 4-1). Similar zinc m i n e r a l i z a t i o n i s also known i n a few locations i n the southern Richardson Mountains. These l a s t two areas are sampled r e l a t i v e l y sparsely i n t h i s study. The diagrammatic cross-section through the Backbone Ranges (Figure 4—4) outlines the general s t r a t i g r a p h i c r e l a t i o n s of the main carbonate b e l t and demonstrates that the l i t h o s t r a t i g r a p h i c units containing the zinc-lead m i n e r a l i z a t i o n form s i x d i s t i n c t age groups. Figure 5-2 summarizes the d i s t r i b u t i o n of the deposits among these host rock age groups based on information from the 92 deposits a v a i l a b l e to th i s study, and indicates that the older rocks ( i . e . of H e l i k i a n to Lower Cambrian age) contain most of the occurrences. Approximately 63 percent of the deposits are hosted i n Proter-ozoic or Lower Cambrian units whereas the remaining 37 percent are i n Middle Ordovician to Devonian rocks. The segregation of host rocks into two major categories appears to be fundamentally d i s t i n c t on the following groundst 1] the Upper Cambrian to Ordovician carbonate unit comprising the F r a n k l i n Mountain Formation i s r e l a t i v e l y 'barren' of mineralization"'" (Figure 5-2; c . f . Figures 4-4 and 4-5) and forms a strong delineating horizon between the two age categories, 2] major regional unconformities e x i s t at the base of the Middle and Upper Cambrian ( i . e . at the base of the del i n e a t i n g horizon; c . f . Figures 4-4 and 4-5), and 3] another regional unconformity occurs below the Ordovician to S i l u r i a n aged.Mt. Kindle Formation ( i . e . d i r e c t l y above the delineating horizon; c . f . Figures 4-4 and 4-5). A dominance of zinc-lead m i n e r a l i z a t i o n i n Cambrian and older host rocks Stratabound zinc-lead deposits are known to be present i n the Lower Ordovi-cian Sunblood Formation shales (Archer and Cathro, 1976). Furthermore, minor l o c a l i z e d areas of zinc-lead m i n e r a l i z a t i o n i n Ordovician carbonates are known (McArthur, pers. comm., 1978). Therefore, although t h i s age un i t i s not s t r i c t l y "barren", i t i s notably d e f i c i e n t i n mineral occurrences r e l a t i v e to comparable l i t h o s t r a t i g r a p h i c u n i t s of younger and older ages. 91 been noted previously within t h i s b e l t (Dawson, 1975) and i n the southern Rocky Mountain b e l t (Macqueen, 1976), however no explanations were o f f e r e d . Host Rock Age Devonian S i l u r i a n to Devonian Ordovician to S i l u r i a n Cambrian to Ordovician Lower Cambrian Hadrynian H e l i k i a n Number of Deposits (Total=92) 12 17 Percentage of deposits i n a) 7 age groups b) 2 age groups 13 23 19.5 20.5 (c) 37 63 FIGURE 5-2 BAR GRAPHS SHOWING DISTRIBUTION OF DEPOSITS RELATIVE TO AGES OF HOST ROCKS Data from 92 deposits i n the sample c o l l e c t i o n : (a) number of deposits i n each age i n t e r v a l , (b) data from (a) as a percentage, and (c) general d i s t r i b u t i o n of deposits among two p r i n c i p a l age groups . Such a d i s t r i b u t i o n pattern might be expected to r e l a t e to more favourable l i t h o f a c i e s developed during these periods or to a greater length of time a v a i l a b l e to the older rocks for preparation as a host for m i n e r a l i z a t i o n . In p a r t i c u l a r , no explanation has been forwarded concerning the lack of mi n e r a l i z a t i o n i n the F r a n k l i n Mountain Formation and units of equivalent age. A fundamental r e l a t i o n between time of m i n e r a l i z a t i o n and age of host rock might be of s i g n i f i c a n c e i n explaining these patterns but further 92 discussion on th i s i s deferred to the metallogenic i n t e r p r e t a t i o n s i n Chapter The 'geographic d i s t r i b u t i o n of host rock age groups, contoured to segregate the two major age groups, i s p l o t t e d on Figure 5-3. This contoured d i s t r i b u t i o n r e f l e c t s the generalized geology as exhibited by the deposits studied ( c . f . Figure 4-2). Deposits hosted by carbonate rocks of H e l i k i a n , Hadrynian, and Lower Cambrian age dominate 1) the concave i n t e r i o r of the Mackenzie f o l d b e l t ; p e r i p h e r a l to the Selwyn Basin, 2) a zone that trends northwards into the Bonnet Plume v a l l e y and the core of the Richardson Moun-tains, and 3) a narrow b e l t around the concave e x t e r i o r of the Backbone Ranges Deposits hosted by Ordovician, S i l u r i a n , and Devonian carbonate rocks are concentrated along the central arc of the Backbone Ranges, where t i g h t f o l d -ing and thrusting has produced a r e p e t i t i v e sequence of l i t h o l o g i e s of this age (Figure 4-2). The northwestern-most area, i n the Northern O g i l v i e and Porcupine Ranges, i s represented by deposits i n the younger age carbonate rocks. O v e r a l l , this host age d i s t r i b u t i o n i s r e l a t i v e l y d i s t i n c t ; further i n t e r p r e t a t i o n i s deferred to Chapter 6. Dolomite i s , by fa r , the most common host l i t h o l o g y . Shale and limestone generally p a r t l y dolomitized, contain the remainder of the deposits (Figure 5-4). Tectonic controls over l o c a l i z a t i o n of m i n e r a l i z a t i o n are also strongly indicated because a minimum of 80 percent of the showings are found i n tectonic b r e c c i a matrix f i l l i n g s or veins re l a t e d to f r a c t u r i n g and f a u l t i n g (Figure 5-5; Plates A-1,2,3). For many of the remaining deposits d e t a i l e d descriptions d e f i n i n g how mine r a l i z a t i o n occurs are not a v a i l a b l e , hence th i s percentage might be even higher. At l e a s t one deposit (not studied i n d e t a i l here) i s recorded by f i e l d observations as possibly co n s i s t i n g mainly of syngenetic s p h a l e r i t e ^ . I t should be noted that even though mineralized 1 Deposit 20010 (Ice-Emily) i s described as syngenetic (?) galena and smithson i t e zones up to 400 feet (130 metres) long and 60 feet (19 metres) wide at the top of the Lower Cambrian Sekwi Formation dolomite (Archer and Cathro, 1976). FIGURE 5-3: GEOGRAPHIC DISTRIBUTION OF HOST ROCK AGE GROUPS Ages are coded as follows: © O Devonian • vO r d o v i c i a n - S i l u r i a n ^OHadrynian B • Silurian-Devonian ^^Lower Cambrian A A H e l i k i a n Symbols i n d i c a t e l o c a t i o n s of s p h a l e r i t e analyzed i n this study (closed) and of other specimens i n the c o l l e c t i o n (open). S t i p p l e d areas denote d i s t r i b u t i o n s of Ordovician-Devonian host rocks. 94 breccias normally are the/richest zones i n any deposit, other types of occurrence such as replacement, s o l u t i o n c a v i t y and vug f i l l i n g , and l o c a l l y some apparently s t r a t i f o r m syngenetic disseminations and lenses, are also described for many deposits (Archer and Cathro, 1976) . O v e r a l l , throughout Litholdgy Dolomite Limestone Shale Number of Deposits Percentage of Deposits 75 N y//////m i i (a) FIGURE 5-4 SI 12 (b) BAR GRAPHS SHOWING DISTRIBUTION OF DEPOSITS RELATIVE TO HOST LITHOLOGY. (Data from 92 deposits i n sample c o l l e c t i o n ) (a) number of deposits i n each l i t h o l o g y (b) data from (a) as a percentage the region, f i e l d information indicates that t e c t o n i c f r a c t u r i n g , f a u l t i n g , and associated b r e c c i a t i o n provided both the major conduits f o r f l u i d migration and the open spaces f o r p r e c i p i t a t i o n of the "ore" minerals. Due to t h i s dominance of b r e c c i a c o n t r o l and to a lack of d e s c r i p t i v e information to permit c l a s s i f i c a t i o n of many of the remaining deposits, i t was not possible to study geographic v a r i a t i o n s of deposit types. F i e l d descriptions and sample c h a r a c t e r i s t i c s i n d i c a t e that l i t t l e or no d i s s o l u t i o n of the host rock accompanied m i n e r a l i z a t i o n . The angularity of the b r e c c i a fragments suggests either that mineralizing solutions from which the matrix minerals were p r e c i p i t a t e d were non-corrosive to the host rock, or that m i n e r a l i z a t i o n occurred independent of b r e c c i a t i o n . Therefore, i t appears that ground preparation of the host might have occurred w e l l i n advance of m i n e r a l i z a t i o n (by dolomitization, natural reef talus b r e c c i a t i o n , or s o l u t i o n cavity or karst formation), or, i n some cases only s h o r t l y p r i o r to m i n e r a l i -zation (by tectonic f a u l t i n g , f r a c t u r i n g , and b r e c c i a t i o n ) . 95 Mode of Emplacement Number of Deposits Percentage of Deposits Unknown Brecc i a t i o n Vein Fracture F i l l i n g A85 Syngenetic (?) 1 (a) FIGURE 5-5 •1 (b) BAR GRAPHS SHOWING DISTRIBUTION OF DEPOSITS RELATIVE TO MODE OF EMPLACEMENT OF MINERALIZATION. (Data from 92 deposits i n sample c o l l e c t i o n ) See text f o r explanation of 'syngenetic ( ? ) ' . (a) number of deposits i n each category (b) data from (a) as a percentage Petrographic examination of 60 polished sections (Appendix A) revealed an o v e r a l l s i m p l i c i t y and s i m i l a r i t y i n the mi n e r a l i z a t i o n within and between the deposits. Sparry c a l c i t e and dolomite are the dominant gangne minerals accompanying the sulphide m i n e r a l i z a t i o n (Plate A-1,2,3) and these appear to have formed ei t h e r p r i o r to or l a t e r than ore mineral sulphides . Sparry carbonate v e i n l e t s are abundant within the host rocks and are commonly found as the i n i t i a l coatings on b r e c c i a fragments or along v e i n boundaries. Fine c a r b o n a t e - f i l l e d fractures cross-cut a l l but the coarsest and the s i l i c i o u s hosted s p h a l e r i t e specimens (Plate A-2); a post sulphide phase of veining i s thus, generally i n d i c a t e d , Sphalerite normally dominates the sulphide miner-alogy. S p e c i f i c proportions of sulphide minerals are d i f f i c u l t to assign because most specimens studied were selected i n the f i e l d with a s p e c i f i c bias towards pure, coarse grained s p h a l e r i t e . Dawson's (1975) previously estimated r a t i o of sphalerite:galena being 10:1 appears to be a f a i r , i f not low, estimate. Galena and p y r i t e are the common sulphide accessory minerals, and eith e r co-precipitated i n small amounts with sphalerite, or, more commonly, formed a f t e r the main s p h a l e r i t e deposition. L o c a l l y galena has p a r t i a l l y replaced e a r l i e r s p h a l e r i t e . A number of showings record copper m i n e r a l i z a t i o n 96 as w e l l (e.g. deposit 10042); traces of chalcopyrite or t e t r a h e d r i t e occur i n these deposits. One sample analyzed (number 10042-15) contained a nodule of massive bournonite with associated malachite and a z u r i t e enclosed w i t h i n a l a r g e r s p h a l e r i t e bleb. Quartz, where present, i s normally the youngest mineral to p r e c i p i t a t e and forms large euhedral c r y s t a l s i n vugs. A few deposits occur i n h i g h l y s i l i c i f i e d host rocks and the gangue i s almost e n t i r e l y quartz. A generalized paragenetic sequence for zinc-lead m i n e r a l i z a t i o n of the region, as determined from hand specimen and polished section examinations (Appendix A), i s : 1] ground preparation p r i o r to m i n e r a l i z a t i o n by dolomitization followed by tectonic f r a c t u r i n g and b r e c c i a t i o n , 2] p a r t i a l i n f i l l i n g of open spaces, fractures, e t c . by an i n i t i a l carbonate phase (t h i s i s not always evident), 3] dominant s p h a l e r i t e deposition, sometimes accompanied by minor p y r i t e , galena, or carbonate, 4] an accessory sulphide phase, consisting of galena, p y r i t e , chalco-p y r i t e , t e t r a h e d r i t e , or bournonite, with or without minor s p h a l e r i t e or carbonate gangue, 5] l a t e sparry carbonate f i l l i n g or l i n i n g the remaining spaces, 6] l a t e quartz, commonly represented by euhedral c r y s t a l s l i n i n g vugs (the timing of large scale s i l i c i f i c a t i o n or the paragenesis of s i l i c i f i e d showings r e l a t i v e to the more normal carbonate paragenesis i s unknown), 7] l a t e f r a c t u r i n g of both the host and the m i n e r a l i z a t i o n with subsequent i n f i l l i n g by f i n e sparry carbonate (the exact timing of t h i s common feature i s unknown; i t might be r e l a t e d to phase 5] i n some cases, or might be a f t e r 8]), and 8] l a t e p r e c i p i t a t i o n of pyrobitumen. This sequence does not describe a l l the c h a r a c t e r i s t i c s of a l l the deposits, however i t does define the dominant c h a r a c t e r i s t i c s of b r e c c i a t i o n , sparry carbonate gangue, and s p h a l e r i t e dominance of the sulphide mineralogy. Minor departures from t h i s sequence are.expected due to complex changes i n factors such as temperature or chemical composition of the mineralizing f l u i d s . The small v a r i e t y of mineral textures observed i n hand specimens 97 (Appendix A) might be due to these f a c t o r s . Supergene oxidation of these showings v a r i e s considerably, probably i n r e l a t i o n to degree of surface exposure. Zinc r e a d i l y oxidizes to a h i g h l y mobile sulphate state, which quickly reacts with carbonates to form Z n C 0 3 (Boyle and Jambor, 1963). Smithsonite i s generally present i n these deposits and i n a few cases occurs as massive 'dry bone ore'. Hydrozincite i s also common as t h i n coatings on many s p h a l e r i t e grains. 5.2 Minor Element C h a r a c t e r i s t i c s of Sphalerite from the Northern C o r d i l l e r a The minor element assemblage determined f o r the sphalerite specimens from the northern c o r d i l l e r a includes those elements most often found assoc-ia t e d with t h i s mineral. A summary of the quantitative atomic absorption a n a l y t i c a l r e s u l t s i s given i n Table 5-2. Dominant constituents i n Table 5-2, as expected, are cadmium and i r o n , these being the only elements with mean values i n the thousands of ppm range. Cadmium, the only element with a standard deviation l e s s than the mean value, displays the l e a s t f l u c t u a t i o n i n concentration across the region as a whole. The extreme range of values i s 172 to 9424 ppm, however, 1000 to 3000 ppm i s a more representative range. This s t a b i l i t y i n regional d i s t r i b u t i o n has been noted i n other areas (Sims and Barton, 1961; Nash, 1975) and has .been at t r i b u t e d to the f a c t that s p h a l e r i t e i s the only common ore mineral which accepts considerable amounts of cadmium i n t o i t s st r u c t u r e . Therefore there i s no competition from other sulphides to p a r t i t i o n s i g n i f i c a n t amounts away from s p h a l e r i t e ( c . f . section 2.3.1), Iron contents of s p h a l e r i t e s (Table 5-2) range from a low of 92 ppm to a high of 3,58 weight percent, with a more c h a r a c t e r i s t i c range (representing 98 TABLE 5-2 REGIONAL SUMMARY OF QUANTITATIVE ATOMIC ABSORPTION SPECTROGRAPHIC ANALYTICAL RESULTS (based on analyses of 166 samples) Element Range (ppm) Mean (ppm) Start! ** ** S i l v e r 0 -- 295 13.5 30 Cadmium 170 - 9424 1780 904 Cobalt 0 - :98;; 3.3 12 Copper 5 - 2100 172 312 Iron 92 - 35870 2750 3815 Manganese 0 - 230 30 34 Nick e l 0 - 70 0.7 5.7 Lead 0 - 10750 644 1274 Mercury 0 - 300 33 64 * 0 = not detected; r e f e r to Table 3-3 f o r detection l i m i t s ** Mean values and standard deviation are calculated using 0 as an a n a l y t i c a l r e s u l t 70 percent of the analyses) of 500 to 7000 ppm. Only seven samples contain over one weight percent i r o n , i n d i c a t i n g that the i r o n contents are generally r e l a t i v e l y low. Some of the w e l l sampled deposits are characterized by low i r o n (e.g. deposit 20023 i s represented by 20 samples, a l l of which contain less than 500 ppm i r o n ) ; consequently the i r o n content i n s p h a l e r i t e could provide a method of d i s t i n g u i s h i n g i n d i v i d u a l deposits. Manganese i s often grouped with i r o n and cadmium as the most common elements contained within the sph a l e r i t e structure (Boyle and Jambor, 1963; Stoiber, 1940). However, the samples from the northern c o r d i l l e r a provide rather low manganese values. The maximum a n a l y t i c a l r e s u l t i s 230 ppm and only nine values exceed 100 ppm; the mean i s approximately 30 ppm (Table 5-2), This r e s t r i c t e d range of values has lead to manganese being the second most 99 evenly d i s t r i b u t e d element, even though the standard deviation i s 115 to 120 percent of the mean. Lead exhibits an appreciable range of concentrations about i t s mean value. Part of t h i s v a r i a b i l i t y may be due to contamination from trace amounts of galena, however, some samples contained i n s u f f i c i e n t lead to be detected. A number of w e l l sampled deposits (numbers 10042, 20012, and 20025) contain d i s t i n c t l y low lead values r e l a t i v e to the regional mean. Regional v a r i a b i l i t y of copper tends to be high, with a n a l y t i c a l r e s u l t s extending from a few ppm to over 2000 ppm. The r e s u l t i n g standard deviation i s 180 percent of the mean value. Copper m i n e r a l i z a t i o n i s associated with the s p h a l e r i t e i n some deposits (e.g. number 10042), hence contamination from t h i s source might contribute to the v a r i a b i l i t y i n a n a l y t i c a l r e s u l t s . Again, s p e c i f i c deposits (e.g. numbers 10033, 20023, and 20025) are character-i s t i c a l l y low i n copper concentrations. Mercury exhibits a highly v a r i a b l e and somewhat unique d i s t r i b u t i o n . In t h i s case some deposits (e.g. numbers 10033 and 10042) are d i s t i n c t l y enriched i n mercury r e l a t i v e to the regional mean. The o v e r a l l sample range, from le s s than 0.1 ppm to over 300 ppm, r e f l e c t s the h i g h l y v a r i a b l e regional d i s t r i b u t i o n . Of i n t e r e s t also i s the d i s t r i b u t i o n within s i n g l e deposits. For example, the highest value obtained (310 ppm) comes from the Rev deposit (number 20023) whereas the 19 other samples from t h i s deposit each contain l e s s than 3.5 ppm mercury (Table 3-7)- Four samples from deposit number 10027 contain from 190 to 295 ppm mercury, yet a f i f t h sample contains i n s u f f i c i e n t mercury to be detected (Table 3-7) . This high v a r i a -b i l i t y across the region and w i t h i n deposits might be r e l a t e d to the occur-rence of v o l a t i l e mercury during p r e c i p i t a t i o n of s p h a l e r i t e . In t h i s state small physiochemical changes i n the mineralizing solutions might produce large e f f e c t s on the incorporation of mercury. 100 S i l v e r values are low across the region however the large standard deviation of the samples r e l a t i v e to the mean indicates a large regional v a r i a b i l i t y . In t h i s case some of the most sampled deposits are p a r t i c u l a r l y enriched i n s i l v e r , but others are depleted, r e l a t i v e to the regional mean. Cobalt and n i c k e l , two elements often linked geochemically ( p a r t i c u l a r l y as minor elements i n p y r i t e ) , are both present i n detectable quantities i n only a few samples (cobalt i n 24 samples, n i c k e l i n only f i v e samples; Table 3-7). Therefore l i t t l e can be said regarding t h e i r d i s t r i b u t i o n . Cobalt ranges up to 98 ppm and at l e a s t two deposits show consistency i n cobalt content within each of the three representative samples. The highest n i c k e l value i s 70 ppm. Many of the elements determined by emission spectrographic methods are i n a category s i m i l a r to cobalt and n i c k e l since l e s s than 25 percent of the samples analyzed (which i n t h i s case t o t a l s 162) contained detectable amounts of antimony, arsenic, chromium, strontium, vanadium, or barium. A summary of the emission spectrographic r e s u l t s i s given i n Table 5—3. Antimony, arsenic, and strontium a l l have high detection l e v e l s (Table 3-2), hence t h e i r d i s t r i b u t i o n s are l i k e l y truncated at lower concentrations and no patterns can be observed i n the few detectable analyses a v a i l a b l e . Barium and vanadium have an i n s u f f i c i e n t number of r e s u l t s to i l l u s t r a t e t h e i r d i s t r i b u t i o n and chromium shows no preferred d i s t r i b u t i o n i n the 36 analyses above the detection l i m i t . Titanium and gallium are present i n 75 percent of the deposits studied (titanium occurs i n 58 percent of the samples and gallium i n 80 percent of the samples) and t i n i s present i n over 50 percent of the deposits (37 percent of the samples). O v e r a l l , the emission spectrographic analyses with the most p o t e n t i a l f o r providing meaningful q u a l i t a t i v e information w i l l be from those elements that have been detected i n approximately 20 to 80 percent of the deposits. 101 TABLE 5-3 REGIONAL SUMMARY OF EMISSION SPECTROGRAPHIC ANALYTICAL RESULTS (based on 162 sample analyses) Element Mean Standard Deviation (±ppm) Percentage of Samples Represented Antimony Arsenic Barium Chromium Gallium Strontium Tin Titanium Vanadium Beryllium Bismuth Molybdenum Platinum 0*- 3000 31** 85** 18 0 - 500 6 47 02 0 - 1500 28 163 05 0 - 2 0 0.8 2.4 22 0 - 400 16 35 79 0 - 800 25 110 10 0 -100 5 13 36 0 - 2500 50 280 57 0 - 30 0.5 3.4 05 not detected * 0 = not detected; r e f e r to Table 3-2 f o r detection l i m i t s ** Mean values and standard deviations are calculated using 0 as an a n a l y t i c a l r e s u l t 5.3. Analysis of Element D i s t r i b u t i o n 5.3.1 Analysis of Variance The preceding s e c t i o n has indicated that i n the more obvious cases of the w e l l sampled deposits, c e r t a i n elements e x h i b i t c h a r a c t e r i s t i c a l l y high or low concentrations. I f characterizations such as th i s occur throughout the region then a summation of the r e s u l t s from each sample i n a deposit w i l l produce a mean a n a l y t i c a l value representative of that deposit alone. 102 An investigation of this can be made through an analysis of variance aimed at determining i f the sample variances within a single deposit are s i g n i f -icantly larger or smaller than the variations between deposits across the region. Burnham (1959) has used such an approach to present additional informa-tion on the existence of d i s t i n c t metallogenic provinces i n the southwestern U.S.A. and northern Mexico using the t i n content of chalcopyrite. He con-cluded that the d i s t r i b u t i o n of t i n . revealed a s i g n i f i c a n t l y greater v a r i a -tion between each mining d i s t r i c t than the v a r i a t i o n found within each mining d i s t r i c t . Therefore he s a t i s f i e d his o r i g i n a l goal of demonstrating that "a d e f i n i t e geographic d i s t r i b u t i o n i s more fir m l y established i f i t can be shown that the variance about the grand mean i s s i g n i f i c a n t l y greater than the variance about the d i s t r i c t means" ( i b i d . , p. 47). In t his study the nine deposits represented by f i v e or more samples provide a suitable data matrix, to study the variances within each deposit r e l a t i v e to the variances about the regional mean. Tabulations of the data used and calculations are included i n Appendix C, Table C-3. Comparison of the calculated F-ratio at the 95 percent confidence l e v e l indicates that for a l l elements the within and between deposit components of the t o t a l natural sample variance are drawn from two independent sources. Therefore the data v a r i a b i l i t y between deposits can be considered s i g n i f i c a n t l y greater than that within the deposits. This determination indicates that each deposit can e f f e c t i v e l y be 'finger printed' on the basis of i t s minor element content. I t also i s c r i t i c a l i n j u s t i f y i n g the calculation of representative mean an a l y t i c a l values for each deposit and thereby reducing the data population to 48 i n d i v i d u a l points, each with equal weighting. In the case of lead, the computed F-ratio i s close to the c r i t i c a l F-ratio while for a l l other elements the computed F-ratio i s much higher than 103 the c r i t i c a l F - r a t i o . This r e l a t i v e lack of regional between-deposit v a r i a b i l i t y i n lead content might be r e l a t e d to the common occurrence of galena as the commonest and most abundant accessory sulphide i n these deposits. Sims and Barton (1961) noted a common occurrence of lead i n sphal-e r i t e samples not obviously contaminated by galena and they attrubuted t h i s lead content to the "approximate l i m i t of s o l i d s o l u t i o n of galena i n sphal-e r i t e at the temperatures p r e v a i l i n g during the m i n e r a l i z a t i o n " ( i b i d . , p. 123). Regional lead values i n s p h a l e r i t e from the northern c o r d i l l e r a are not exceptionally high compared to the above wock by Sims and Barton and a s i m i l a r underlying control on i t s d i s t r i b u t i o n might be s i g n i f i c a n t i n t h i s area. However, the p o s s i b i l i t y of contamination by galena cannot be ruled out. Isolated samples bearing anomalous lead derived from galena could r a i s e within deposit variances to a point where they could not be distinguished from between deposit variances. Table 5-4 contains the mean a n a l y t i c a l values for each element, c a l c u -lated to represent the 48 deposits across the area of i n t e r e s t . The following regional i n t e r p r e t a t i o n s are drawn from t h i s data base. 104 T A B L E 5-4 M E A N A T O M I C A 3 S O R ° T I O N A N A L Y T I C A L R E S U L T S F O R 4 8 D E P O S I T S I D . N O . E N D I N G I N - 0 9 0 D E N O T E S M E A N V A L U E M A S B E E N C A L C U L A T E D 0 = N O T D E T E C T E D : S E E T A B L E 3 - 3 C 0 R D E T E C T I O N L I M I T S N . D . = N O T D E T E R M I N E D T O . N O . A G C O C O c u FE M N N I P B H G 1 0 C C 6 9 9 9 7 . 1 9 5 4 1 2 . 7 9 5 1 2 4 1 6 4 1 0 . 0 1 2 4 5 1 . 8 3 1 0 0 1 C 0 0 1 5 9 . 4 1 1 1 0 0 . 0 1 0 1 2 0 1 6 5 0 . 0 1 8 5 0 0 . 0 7 1 0 0 7 0 0 0 4 3 7 . R 1 4 6 0 5 . 4 3 9 4 6 3 1 3 7 3 0 0 . 0 4 7 7 N . D . 1 0 0 2 7 0 0 4 3 5 . 6 7 0 6 2 2 . 1 1 7 2 9 1 8 0 3 2 0 . 0 3 7 1 1 1 2 . 5 0 1 9 0 7 4 9 9 9 1 1 . 0 1 7 7 0 4 . 9 1 2 8 3 4 1 6 2 1 0 . 0 9 2 9 1 0 7 . 0 0 1 0 0 2 5 9 9 9 2 . 7 1 7 3 8 0 . 0 4 6 2 3 9 2 1 2 0 . 0 6 0 5 5 . 7 0 1 0 0 2 6 0 0 1 4 5 . 1 1 4 2 5 3 . 4 . 4 1 2 6 8 1 2 4 7 0 . 0 1 2 7 9 8 . 0 0 1 0 0 2 7 9 9 ° 1 3 . 8 2 0 S 1 0 . 0 1 8 4 1 5 5 0 1 3 0 . 0 4 3 0 7 1 5 . 0 0 1 0 0 2 8 9 9 9 2 . 3 3 3 2 3 0 . 0 1 2 1 1 0 4 0 0 . 0 1 7 3 4 . 8 5 1 0 0 7 9 9 9 9 7 . 4 2 2 8 4 0 . 0 1 9 2 6 3 4 5 6 . 5 6 0 9 0 . 7 2 1 0 0 3 0 0 0 1 4 5 . 5 1 7 2 2 7 . 9 5 1 3 1 2 1 4 0 7 5 1 2 . 0 1 0 7 5 0 6 0 . 0 0 1 0 0 3 2 0 0 1 6 . 8 1 1 0 0 9 7 . 9 9 7 3 5 3 7 0 8 3 0 . 0 3 8 7 9 N . D . 1 0 0 3 3 9 9 9 4 3 . 1 1 5 6 0 0 . 0 6 9 1 7 7 6 2 0 . 0 2 0 4 7 6 . 2 3 1 0 9 3 4 ° 9 9 0 . 0 8 6 0 2 . 4 1 7 2 1 5 0 8 0 . 0 6 6 0 5 . 5 0 1 0 0 3 5 9 9 9 1 4 . 8 2 3 6 0 0 . 0 3 2 8 2 3 7 0 4 5 C O 9 9 3 . 2 5 1 0 0 3 6 9 9 9 2 7 . 8 1 1 3 2 0 . 0 5 6 7 2 5 0 0 1 5 0 . 0 3 7 4 1 . 2 5 1 0 0 3 7 9 9 9 3 1 . 6 2 0 3 8 6 . 3 3 3 1 4 7 6 9 7 3 1 . 3 6 5 1 8 . 4 3 1 0 0 4 2 9 9 9 2 4 . 8 1 6 2 6 3 . 1 1 9 8 3 2 0 3 5 0 0 . 0 7 7 5 7 0 . 6 0 1 0 0 4 3 9 9 9 0 . 0 1 4 4 3 0 . 0 1 4 2 2 2 0 2 0 . 0 1 5 0 1 . 1 1 1 0 0 4 4 0 0 1 4 . 9 1 7 6 0 0 . 0 7 2 2 4 9 5 4 2 2 . 0 . 0 3 0 9 0 . 0 0 1 0 0 4 5 0 0 1 5 . 7 2 6 7 6 0 . 0 2 9 2 5 2 6 3 0 . 0 2 3 5 0 . 8 1 1 0 O 6 ° 9 9 1 4 . 9 1 6 4 7 0 . 0 6 2 0 4 6 8 9 1 6 0 . 0 5 7 1 2 9 . 2 5 1 0 0 5 0 0 0 1 0 . 0 6 9 3 0 . 0 4 0 1 0 1 1 1 5 0 . 0 4 7 ? N . D . 1 0 0 5 3 0 0 1 4 . 3 1 7 9 5 0 . 0 5 8 5 9 8 0 . 0 3 7 N . D . 2 0 C 0 3 9 9 9 1 . 8 1 9 C 6 0 . 0 7 8 7 6 2 0 6 0 . 0 6 2 9 2 3 . 2 5 7 0 0 0 4 9 9 9 0 . 0 1 4 2 4 0 . 0 7 5 3 6 5 8 3 7 0 . 0 1 1 4 9 . 1 3 2 0 0 0 5 9 9 9 1 . 3 4 5 2 6 0 . 0 6 0 3 0 1 8 1 6 0 . 0 6 3 0 0 . 0 0 2 0 0 0 6 9 9 9 3 . 5 1 2 ? ° 4 5 . 9 7 7 3 6 8 1 9 1 1 0 . 0 1 4 5 9 5 . 3 6 2 0 0 0 3 ^ 9 9 0 . 0 7 6 1 0 . 0 3 1 4 4 2 1 4 0 . 0 3 9 3 0 . 0 0 7 0 0 0 9 0 0 4 0 . 0 2 3 9 3 0 . 0 1 0 1 3 2 6 2 1 0 . 0 1 3 3 1 0 . 4 9 2 0 0 1 2 9 9 9 4 . 5 1 3 4 0 4 . 7 7 9 7 3 6 2 7 0 . 0 1 4 4 1 5 3 . 6 4 2 0 C 1 3 0 0 1 3 . 5 1 5 2 2 0 . 0 1 7 3 7 2 0 3 2 0 . 0 2 7 1 N . D . 2 0 0 1 5 0 0 ^ 9 . 1 1 4 5 3 0 . 0 1 8 3 7 5 6 7 1 3 5 0 . 0 4 6 5 • N . D . 2 0 0 2 0 0 0 ? 0 . 0 8 1 3 0 . 0 7 3 8 0 7 6 5 1 0 . 0 1 0 1 N . D . 2 0 0 1 9 0 0 4 5 . 8 3 6 3 0 . 0 3 7 1 9 9 3 2 2 0 . 0 1 0 3 0 . 2 9 2 0 0 2 1 9 9 9 7 . 1 3 0 7 5 0 . 0 1 7 6 1 4 3 5 4 5 0 . 0 2 3 7 1 . 4 7 2 0 0 2 3 9 9 9 1 . 6 2 3 3 6 0 . 0 2 0 2 6 1 3 9 0 . 0 4 2 5 1 . 1 0 2 0 0 7 4 9 9 9 3 0 . 7 1 6 0 6 0 . 0 1 6 6 1 2 9 3 7 6 0 . 0 2 1 9 1 . 7 8 2 0 0 2 5 9 9 9 1 . 8 1 5 6 0 0 . 0 4 1 4 3 3 7 0 . 0 3 7 1 3 . 8 5 2 0 0 7 7 9 9 9 0 . 0 2 0 1 3 6 . 2 3 2 3 2 9 9 . 3 4 0 . 0 3 5 4 1 1 6 3 . 5 0 2 0 C 3 2 0 0 1 6 9 . 4 1 1 7 0 0 . 0 1 0 1 5 5 1 4 2 0 . 0 1 5 1 2 2 . 4 0 2 0 0 3 4 9 9 9 1 . 1 1 2 5 8 0 . 0 7 3 4 5 1 8 1 9 0 . 0 4 2 1 9 . 3 4 7 0 0 3 5 9 9 9 1 . 4 1 3 9 6 0 . 0 3 8 1 1 5 4 1 1 5 1 7 . 5 3 8 8 4 . 0 6 2 C 0 3 6 9 9 9 1 . 7 1 6 5 3 6 . 6 1 2 3 4 9 8 9 1 6 0 . 0 1 9 5 . 0 ? 7 0 0 3 7 9 9 9 2 6 . 6 1 9 3 7 0 . 0 2 0 4 1 7 4 4 7 1 0 . 0 9 8 0 . 0 7 2 0 C 3 3 0 0 1 0 . 0 I 1 7 6 0 . 0 1 5 7 6 0 7 3 5 0 . 0 0 1 1 . 8 0 2 0 0 3 9 0 0 1 1 1 . 1 1 1 9 6 0 . 0 1 3 6 3 6 5 4 9 0 . 0 n 2 . 3 1 2 0 0 4 0 9 9 9 0 . 0 4 2 3 7 0 . 0 4 3 2 4 3 2 1 8 0 . 0 5 2 9 . 8 0 105 5.3.2 Inter-element C o r r e l a t i o n and Regression Analysis C o r r e l a t i o n c o e f f i c i e n t matrices f o r eight elements, s c a t t e r diagrams, and l i n e a r regression equations f o r element pairs were calculated using the UBC TRP computer program (Le and T e n i s c i , 1977) . C r i t i c a l c o e f f i c i e n t s were determined at appropriate confidence l i m i t s using Table A-30a of Dixon and Massey (1969) . I n i t i a l l y , c o r r e l a t i o n matrices were calculated f o r the 166 sample analyses and f o r the 48 deposit mean values. The r e s u l t s h i g h l i g h t a strong p o s i t i v e r e l a t i o n s h i p amongst cobalt, i r o n , and lead (Table 5-5, Figure 5-6) for both c a l c u l a t i o n s . Manganese and s i l v e r tend to exhibit p o s i t i v e c o r r e l a -tions; these also c o r r e l a t e with lead i n the dominant t r i o . Cadmium, however, exhibits strong negative c o r r e l a t i o n s with these elements. Scatter plots and b e s t - f i t l i n e a r regression equations of the form y=a + bx were determined f o r a l l possible element p a i r s , using the 48 deposit mean values. I n i t i a l i n t e r p r e t a t i o n of the p l o t s suggested two trends, r e l a t e d to host rock age groups, were present. Individual c o r r e l a t i o n matrices, s c a t t e r diagrams, and regression equations were then determined for (1) the 27 deposits hosted i n Proterozoic and Lower Cambrian rocks, and (2) the 21 deposits hosted i n Ordovician, S i l u r i a n , and Devonian rocks; i s o l a t e d , o u t l y i n g points which unduly overweight the regression l i n e were not included i n regression c a l c u l a t i o n s . Correlations c a l culated from deposit mean data from the two host rock age groups provide s i m i l a r patterns to those calculated f o r a l l the data (Figure 5-7; c f . Figure 5-6); the major differences are that cadmium does not enter i n t o s i g n i f i c a n t negative c o r r e l a t i o n s i n the younger host group and i r o n does riot c o r r e l a t e with lead. Linear regressions, however, i n d i c a t e ^ N i c k e l provided i n s u f f i c i e n t data f o r analysis by th i s method. 106 TABLE 5-5 CORRELATION MATRICES AMONGST EIGHT ELEMENTS FOR a) 166 SAMPLE ANALYSES AND b) 48 DEPOSIT MEAN VALUES AG CD CO CU FE MN PB AG 1.000 CD 0.021 1.000 CO -0.026 -0.185 1.000 CU 0.058 -0.082 0.049 1.000 FE 0.028 -0.208 0.658 0.067 1.000 MN 0.161 0.016 0.092 0.155 0.150 1.000 PB 0.122 -0.118 0.328 0.049 0.345 0.246 1.000 HG 0.132 -0.027 -0.070 -0.031 -0.068 -0.098 0.076 a) 166 samples r > 9 Q = 0.100 r i 9 5 = 0.127 AG CD CO CU FE MN PB AG 1.000 CD --0.263 1.000 CO 0.038 -0.242 1.000 CU 0.007 -0.144 0.027 1.000 FE 0.036 -0.236 0.881 -0.057 1.000 MN 0.569 -0.218 0.150 0.170 0.181 1.000 PB 0.352 -0.321 0.517 0.025 0.481 0.233 1.000 HG 0.069 0.010 -0.024 -0.089 -0.050 -0.130 0.218 b) 48 deposits r „„= 0.188 r = 0.245 .yu .y_> 107 Cd Cd A) 166 sample values B) 48 deposit mean values FIGURE 5-6 SCHEMATIC REPRESENTATION OF CORRELATIONS AMONG ELEMENTS FOR A) 166 SAMPLE ANALYSES, AND B) 48DEPOSIT MEAN VALUES Double l i n e s i n d i c a t e strong p o s i t i v e c o r r e l a t i o n s (95% confidence l e v e l ) ; s i n g l e l i n e s show good p o s i t i v e c o r r e l a t i o n s (90% confidence l e v e l ) ; dashed l i n e s follow strong negative correlations (95% confidence l e v e l ) . A) Proterozoic and Lower Cambrian values B) Ordovician, S i l u r i a n , and Devonian values FIGURE"5-7 SCHEMATIC REPRESENTATION OF CORRELATIONS AMONG ELEMENTS FOR SPHALERITE TAKEN FROM A) PROTEROZOIC AND LOWER CAMBRIAN HOST ROCKS, AND B) ORDOVICIAN, SILURIAN, AND DEVONIAN HOST ROCKS. Symbols as i n Figure 5-6. 108 that the data from the two host rock age groups might be d i s t i n c t l y d i f f e r e n t . Three s c a t t e r diagrams, s i l v e r versus manganese (Figure 5-8), cadmium versus mercury (Figure 5-9), and i r o n versus manganese (Figure 5-10) are reproduced here to i l l u s t r a t e these d i f f e r e n c e s . For most element p a i r s , a much broader s c a t t e r of data i s associated with the deposits hosted i n older rocks; t h i s i s p a r t i c u l a r l y evident at high concentration l e v e l s (Figures 5-8 and 5-10). Considerable overlap of data from the two age groups i s seen at the lower concentration l e v e l s . B e s t — f i t l i n e a r regressions show markedly d i f f e r e n t trends i n most cases (Figures 5-8 and 5-9); these l i n e s sometime define s i m i l a r trends but the greater scat t e r of data i n deposits hosted i n older rocks produces notably d i f f e r e n t regression l i n e s (Figure 5-10). These s c a t t e r plots emphasize a fundamental d i f f e r e n c e i n the data obtained from sphal e r i t e s taken from the two major host age groups. The nature of the differences i s not c l e a r from this data but the dominance and greater sca t t e r of higher concentrations i n the older host rocks requires further i n v e s t i g a t i o n ; the s i g n i f i c a n c e of t h i s pattern w i l l be explained further i n the following section (5.3.3) concerning p r o b a b i l i t y graph analysis of the data. 5.3.3 Regional D i s t r i b u t i o n s of Minor Elements Regional patterns i n the d i s t r i b u t i o n of the minor elements were inves-tigated by p a r t i t i o n i n g the a n a l y t i c a l r e s u l t s of the 48 deposits i n t o i n t e r n a l populations with the aid of the p r o b a b i l i t y graph technique of S i n c l a i r (1976). This method allows p a r t i t i o n i n g of data i n t o sub-populations on the basis of assumptions concerning the i d e a l form of the density d i s t r i b u -tions f or each element. Various authors ( S i n c l a i r , 1974; Parslow, 1974) have argued that there i s no v a l i d reason why threshold values must be chosen on 109 Manganese (ppm) FIGURE 5-8: SCATTER DIAGRAM OF SILVER VERSUS MANGANESE Squares and s o l i d regression l i n e represent data from Proterozoic and Lower Cambrian hosts. C i r c l e s and dashed regression l i n e denote data from Ordovician to Devonian hosts. r^= the proportion of v a r i a b i l i t y i n the dependant v a r i a b l e accounted f o r by the independant v a r i a b l e . o no 4-J 3 J 2 J fa 4 H o Hg = 4.95 + (-0.0005) Cd O O 0 n=20 r 2 = l % O u t l y i n g values not i n c l u d e d Cd Hg B 172 60 O 1340 34 Cd = 1303 +-3.34 Hg n=20 r 2=12% — r -25 FIGURE 5-9: —i— 50 1 75 Mercury (ppm) 100 125 SCATTER DIAGRAM OF CADMIUM VERSUS MERCURY Symbols as i n Figure 5-8. I l l — , , r 1 1 ' 20 40 60 80 100 120 149 Manganese (ppm) FIGURE 5-10: SCATTER DIAGRAM OF IRON VERSUS MANGANESE Symbols as i n Figure 5-8. TABLE 5-6 POPULATIONS AND APPROXIMATE THRESHOLD VALUES DERIVED FROM PROBABILITY PLOTS Inflection Point Percentage of Total Approximate Threshold Population Contents and Overlap Element Population (cum %) Data (ppm) Range % Number 30 '95U 13-14 Silver A >15 , 8%B 2-3 30 70 15 <15 92%B 31-32 B 555A 0-1 83 >1000 95ZA 37-38 Cadmium A 8%B 0-1 83 1000 <1000 92S5B 7-8 B 17 5%A 1-2 75 >25 95%A 34-35 Copper A 7%B 0-1 75 25 B 25 <25 93%B 11-12 5%A 1-2 Iron A 31 >3500 98%A 12-13 12 XB 3-4 31 3500 B 60 400-3500 87.5%B 26-27 2%A 0-1 1%C 0-1 9! 400 C 9 <400 99%C 4-5 0.5%B 0-1 Manganese ' A 90 >4 99%A 1XB 42-43 0 90 4 B 10 <4 . 99XB 4-5 1%A 0 Mercury A 30 »18 99%A 12 5*B 1-2 30 18 B 57 0.3-18 95%B 22-23 1%A 0 87 0.3 C 13 <0.3 100ZC 5 Lead The distribution of lead is essentially unimodal. Furthermore, the mean deposit values were Comments contains 3 exceptionally high values contains 1 exceptionally high value contains 4 exceptionally high values contains 2 exceptionally high values contains 3 'non-detected' values Cobalt Nickel sensitive to regional variations. Analytical results for these elements provided insufficient detectable concentrations for use in probability plots. 113 the basis of c a l c u l a t i o n s i n v o l v i n g the mean and a set number of standard deviations. Therefore, i n t h i s study, i n d i v i d u a l populations were chosen somewhat a r b i t r a r i l y on the basis of assumed density d i s t r i b u t i o n models that appeared to correspond c l o s e l y with the r e a l data. Such a procedure aids i n defining 1) threshold values segregating populations, 2) ranges i n concentration f o r each population, and 3) the possible degree of overlap of populations. Each population so defined, can then be Isolated and examined for geographic d i s t r i b u t i o n patterns. D i v i s i o n s between populations can then be defined by 1) and 2) above, such that there i s a s p e c i f i e d overlap of the populations. P r o b a b i l i t y p l o t s , recorded i n Appendix D, are summarized i n Table 5-6. S i l v e r S i l v e r follows a bimodal d i s t r i b u t i o n on the p r o b a b i l i t y p l o t with only f i v e to eight percent overlap of the populations when segregated at a threshold of 15 ppm (Figure D — l a ) . The upper population has a mean value of 33 ppm and a s l i g h t l y lower dispersion about i t s mean than the lower population with a mean of two to three ppm. This lower population includes ten deposits where s i l v e r was not detected. The geographic d i s t r i b u t i o n of these two s i l v e r populations (Figure 5-11) shows an immediate s i m i l a r i t y to the d i s t r i b u t i o n of host rock ages (Figure 5-3). Higher concentrations of s i l v e r dominate the concave I n t e r i o r of the f o l d b e l t , the Coal Creek Dome, and northward through the Bonnet Plume and Wind River V a l l e y s . The Gayna River deposit (number 20024) i s included i n the upper family and i n d i c a t e s , even i f somewhat uncertainly, a possible continuation of higher concentrations along the northeastern flank of the Backbone Ranges. A prominent b e l t of deposits with a low s i l v e r content follows the core of the Backbone Ranges from the southeast to the northwest FIGURE 5-11: GEOGRAPHIC DISTRIBUTION OF SILVER IN SPHALERITE ©Population A : 1 5 - 7 0 ppm Ag V Population B : 0 - 15 ppm Ag St i p p l e d area denotes the extent of sphalerites 'depleted' i n s i l v e r . u n t i l i t i s cut o f f i n the Bonnet Plume V a l l e y region. Lower concentrations are also indicated f o r deposits within the Northern O g i l v i e Mountains. Data points i n t h i s area are widely spread, but tentative contours are drawn to l i n k regional patterns. The d i s t r i b u t i o n s indicated i n Figure 5-11 take into account the overlap of the populations determined i n the p r o b a b i l i t y p l o t s . Three lower popula-t i o n values are included i n the upper population area and two upper population values are Included i n the lower area. Population boundaries drawn to p a r t i t i o n these points into s t r i c t populations would add perturbations to the boundary l i n e s but would not s i g n i f i c a n t l y change the dominant d i s t r i b u t i o n pattern. Cobalt Cobalt was detected i n only 14 of the deposits, therefore, evaluation of cobalt data on p r o b a b i l i t y graphs was not warranted. However, a plo t of the geographic d i s t r i b u t i o n of cobalt, based on i t s presence or absence i n detectable q u a n t i t i e s , was made; a r e l a t i v e l y d i s t i n c t pattern i s obtained i n Figure 5-12. Concentrations of cobalt greater than one ppm occur around the periphery of the Selwyn Basin from the southeast, to the Coal Creek dome i n the northwest, and northwards i n t o the Bonnet Plume V a l l e y area. A s i n g l e value i n the northeast hints at increased amounts i n t h i s area. Deposits i n the Backbone Ranges, the Richardson, and the Northern O g i l v i e Mountains contain undetectable amounts of cobalt. The only deposit with detectable cobalt, w i t h i n the undetected cobalt region (number 20012) a c t u a l l y contains only one anomalously high cobalt value out of eleven samples thus, the boundaries, as drawn, probably accurately r e f l e c t regional trends. FIGURE 5-12: GEOGRAPHIC DISTRIBUTION OF COBALT IN SPHALERITE ©Cobalt detected • Cobalt not detected S t i p p l e d area denotes the extent of sphalerites with undetected cobalt. 117 Copper Copper i s dominated by a population of higher concentrations representing 75 percent of the o v e r a l l data (Figure D - l ) . The mean value of th i s group i s approximately 185 ppm, however, considerable v a r i a t i o n about t h i s mean i s in d i c a t e d . The lower population, represented by only 12 deposits, has a mean value of approximately 12 ppm. Overlap between the populations i s f i v e to seven percent. The d i s t r i b u t i o n of this element, shown i n Figure 5-13,indicates a somewhat i r r e g u l a r trend of lower concentrations through the ce n t r a l Backbone Ranges. This trend terminates i n the Wernecke Ranges, s i m i l a r to other established trends. Two upper population points are included i n t h i s b e l t and at least one (number 10045 at 29 ppm) l i e s very close to the threshold value of 25 ppm segregating the populations. An i s o l a t e d member of the lower population l i e s i n the Northern O g i l v i e Mountains. The higher concentration population dominates the Selwyn Basin periphery,, the Bonnet Plume v a l l e y area i n the Wernecke Mountains, and displays a strong concentration on the northeastern flank of the Backbone Ranges i n the head-waters of the Mountain River. O v e r a l l , t h i s d i s t r i b u t i o n of copper i n spha l e r i t e r e f l e c t s a r e l a t i v e depletion through the Backbone Ranges, defining a trough of low concentrations within a region of higher concentrations. Iron The p r o b a b i l i t y plot f o r i r o n can be resolved i n t o three populations representing an upper 31 percent, an intermediate 60 percent, and a lower nine percent of the data (Figure D - l c ) . The lowest population contains only four data points but these points do not overlap with the other populations. The mean value of 190 ppm i s s i g n i f i c a n t l y lower than the intermediate (1650 ppm) and upper (6800 ppm) population means. Because only four data co FIGURE 5-13: GEOGRAPHIC DISTRIBUTION OF COPPER IN SPHALERITE • Population A : > 25 ppm Cu T Population B : < 25 ppm Cu St i p p l e d area denotes the extent of sphaler i t e s 'depleted' i n copper. 119 points are included, none of which c l u s t e r together, these deposits are grouped with the intermediate population i n the regional d i s t r i b u t i o n plot (Figure 5-14). The intermediate family contains 29 deposits and exh i b i t s a somewhat higher v a r i a t i o n about i t s mean value than the other populations, leading to a p o s s i b l e overlap of 12 to 13 percent (three to four deposits) with the upper population. On the other hand,:.the upper population overlaps the intermediate by only two percent (zero to one deposit). Figure 5-14 i l l u s t r a t e s the d i s t r i b u t i o n pattern for i r o n and again h i g h l i g h t s a trough of low concentrations w i t h i n a broad b e l t of higher values. The depleted trough is-centered on the arc of the Backbone Ranges and terminates i n the Wernecke Mountains. The four lowest population values f a l l within t h i s trough. Higher concentrations s t i l l are found peripheral to the Selwyn Basin and are d i s t r i b u t e d s p o r a d i c a l l y along the northeastern Backbone Ranges. Over a l l the general configuration revealed i n previous d i s t r i b u t i o n s i s again supported. Mercury Mercury r e s u l t s can be resolved into three populations (Figure D - l d ) . Populations are representative of an upper 30 percent, an intermediate 57 percent, and a lower 13 percent of the t o t a l data (which i n t h i s case t o t a l s 41 deposit mean values). The lower population contains 5 deposits, of which 3 contain no detectable mercury, therefore the mean value i s e s s e n t i a l l y zero ppm. The upper population has a mean value of 60 ppm and tends to have a s l i g h t l y wider variance about i t s mean than does the intermediate population. However i t does not appreciably overlap the Intermediate population. The intermediate population has a mean value, of nine ppm and possibly overlaps the upper family by f i v e percent (one to two deposits) . ho o FIGURE 5-14: GEOGRAPHIC DISTRIBUTION OF IRON IN SPHALERITE ©Population A : > 3500 ppm Fe • Population B : < 3500 ppm Fe St i p p l e d area denotes the extent o f . s p h a l e r i t e s 'depleted' i n i r o n . 121 The geographic d i s t r i b u t i o n of mercury, p l o t t e d i n Figure 5-15, i s s l i g h t l y more complex than the others; t h i s might be due to the trimodal d i s t r i b u t i o n . Highest mercury concentrations occur i n the Wernecke Mountains, and i n the Bonnet Plume and Snake River areas; they also occur scattered along both flanks of the Backbone Ranges, The lowest concentration population generally occurs i n the most c e n t r a l ' l o c a t i o n s of the Backbone Ranges. The intermediate population generally l i e s i n between the lower and higher populations defined above. Regionally, the established trend of lower values forming a trough i n the c e n t r a l Mackenzie Mountains, which i s cut o f f by higher values i n the Wernecke Mountains, i s duplicated f o r the mercury r e s u l t s . I n t e r p r e t a t i o n of points i n the more northern and western areas of Figure 5-15. i s question-able due to v a r i a b i l i t y and s c a r c i t y of data points. Cadmium Cadmium plo t s as a bimodal d i s t r i b u t i o n dominated by an upper population containing 83 percent of the deposits; the mean of t h i s population i s approx-imately 1650 ppm. The remainder of the deposits f a l l i n t o a lower population with a mean of about 790 ppm (Figure D - l e ) . The upper population could be further divided about an i n f l e c t i o n point near eight cumulative percent to provide an uppermost population of three deposits over the 3500 ppm l e v e l . However, since these deposits do not c l u s t e r a t ' a l l , the segregation of data into such a small population appears to be meaningless on a regional basis, hence, they are included w i t h i n the upper population. The gentle slope of the i n d i v i d u a l re-calculated population p l o t s (Figure D-le) i l l u s t r a t e s the low v a r i a t i o n about the mean value, r e l a t i v e to other elements throughout the region, a c h a r a c t e r i s t i c p e c u l i a r to cadmium and noted previously (section 5.2). FIGURE 5-15: GEOGRAPHIC DISTRIBUTION OF MERCURY IN SPHALERITE ©Population A : > 18 ppm Hg • Population B : 0.3 - 18 ppm Hg 0 Population C : < 0.3 ppm Hg Sti p p l e d area denotes the extent of sphaler i t e s 'depleted' i n mercury. 123 C o r r e l a t i o n matrices (Table 5-5 and Figure 5-6) i n d i c a t e that cadmium commonly i s negatively correlated with other metals; t h i s i s borne out from a general overview of the d i s t r i b u t i o n patterns. Higher concentrations of cadmium follow a broad b e l t through the c e n t r a l Mackenzie Mountains along the axis of the Backbone Ranges. These high values extend across the northern Yukon (Figure 5—16). Lower values are found towards the Selwyn Basin and possibly along the northeastern flank of the Backbone Ranges. The Bonnet Plume v a l l e y regio.n.does not truncate the regional trends i n t h i s case. Cadmium values do not appear to define regional v a r i a t i o n s as w e l l as other elements; the r e l a t i v e l y uniform d i s t r i b u t i o n of cadmium produces more subtle regional v a r i a t i o n s which are d i f f i c u l t to o u t l i n e i n the methods used. Manganese Manganese d i s t r i b u t i o n i s dominated by a s i n g l e population representing 90 percent of the deposits (Figure D - l f ) . Within t h i s population four deposits are s i g n i f i c a n t l y higher i n concentration, however, they have been included rather than pick a second i n f l e c t i o n point at nine cumulative percent. A larger i n f l e c t i o n occurs at the 90 cumulative percent l e v e l . Therefore, only f i v e deposits represent a lowest population. The four highest values are randomly d i s t r i b u t e d and of the f i v e lowest values, only three show any tendency to c l u s t e r . Hence the data do not provide a meaningful d i s t r i b u t i o n pattern based on p r o b a b i l i t y plot a n a l y s i s . N i c k e l N i c k e l contents i n s p h a l e r i t e were generally below the detection l i m i t s across the region; hence the amount of a v a i l a b l e data f o r a p r o b a b i l i t y p l o t was too low to be i n t e r p r e t a b l e . Only four deposits contained any samples Is3 FIGURE 5-16: GEOGRAPHIC DISTRIBUTION OF CADMIUM IN SPHALERITE ©Population A : > 1000 ppm Cd • Population B : < 1000 ppm Cd Sti p p l e d area denotes the extent of sphaler i t e s 'depleted' i n cadmium. 125 bearing n i c k e l . These four deposit averages ranged from 1.3 ppm to 17.5 ppm but were scattered; hence, no d i s t r i b u t i o n p l o t i s given. Lead The p r o b a b i l i t y plot for lead (Figure D-lg) indicates that lead i s e s s e n t i a l l y unimodal, with perhaps four high values and one low value. As i n the case of manganese, t h i s data i s i n s u f f i c i e n t l y p a r t i t i o n e d to i n t e r -p r e t . Furthermore, i t was determined previously (section 5.3) that l e s s confidence could be placed i n the ch a r a c t e r i z a t i o n of i n d i v i d u a l deposits on the basis of lead content, hence t h i s element might be i n s e n s i t i v e to regional v a r i a t i o n s . 'Combined Metals' Many of the metals f o r which quantitative analyses are a v a i l a b l e i n d i c a t e a s i m i l a r regional pattern i n element d i s t r i b u t i o n . Therefore, a geographic d i s t r i b u t i o n plot was designed to determine i f the high or low populations segregated f o r each element were co-extensive i n t h e i r geographic d i s t r i b u t i o n s . This d i s t r i b u t i o n p l o t i s defined below i n terms of a t o t a l or 'combined metal' content of each deposit. S i l v e r , cobalt, copper, and ir o n contents i n s p h a l e r i t e were chosen f o r i n t e g r a t i o n . Neither lead was included, f o r reasons previously mentioned, nor was cadmium, since i t exhibited an opposite d i s t r i b u t i o n . I n i t i a l l y the data was very simply standardized i n order to remove the dominance of the absolute values of i r o n . Each 'A' population (upper) member determined i n the p r o b a b i l i t y p l o t s was assigned a score of f i v e , each 'B' population (lower i n bimodal d i s t r i b u t i o n s , intermediate i n trimodal d i s t r i b u t i o n s ) member a score of three, and each 'C' population (lower i n trimodal d i s t r i b u t i o n s ) member a score of one. When these scores were summed f o r each deposit the r e s u l t s ranged from a low of 126 10 to a high of 20. Scores of 10 and 20 would represent perfect correspon-dence between low and high populations for a l l four elements r e s p e c t i v e l y . Figure 5-17 e x h i b i t s the regional d i s t r i b u t i o n of these scores using a contour interval of four u n i t s . The pattern developed i s dominated by an arcuate, wavy trend following the Backbone Ranges from the southeast around to the northwest into the Wernecke Mountains where i t i s terminated. The centre of t h i s arcuate trend forms a trough of 'depleted' scores surrounded by i n c r e a s i n g l y 'enriched' scores on each flank. A highly 'depleted' area appears to be centered near the headwaters of the A r c t i c Red River. The extent and shape of t h i s c e n t r a l depression i s poorly defined due to a lack of data points across i t , however scores of 11 to 14 units peripheral to i t strongly support i t s existence. The 'enriched' trend peripheral to the Selwyn Basin turns sharply northwards into the Bonnet Plume v a l l e y area where some of the highest values are found. These are the values that define the sharp termination of the depleted trough i n t h i s area. Northeastern^most deposits are a l l i n the range of 16 to 18 units and confirm that t h i s f l a n k of the Backbone Ranges i s enriched as w e l l . High scores continue across the southern Wernecke Mountains to the Northern O g i l v i e Mountains. Although the data i n the northwestern areas i s too sparse to define exact trends, possible contours (in part drawn to follow the previously indicated population and geologic carbonate trends between data points) are i n d i c a t e d . This t e s t indicates that f o r these four elements the geographic d i s t r i b u t i o n s of the 'enriched' and 'depleted' populations are approximately co-extensive. The dominant trend of each of these populations i s highlighted by the trends of the highest and lowest scores on Figure 5-17,. whereas the zone of intermediate scores represents the area of overlap of population boundaries f o r these four elements. FIGURE 5-17: GEOGRAPHIC DISTRIBUTION OF 'COMBINED METALS' IN SPHALERITE Numbered points represent sums of standardized contents of s i l v e r , cobalt, copper, and i r o n (see text f o r explanation). Contours are drawn for scores 12, 16, and 20. 128 Emission Spectrographic Data Emission spectrographic a n a l y t i c a l r e s u l t s were examined i n a q u a l i t a t i v e manner i n order to determine any d i s t r i b u t i o n patterns that might be evident. Arsenic, strontium, vanadium, and barium were immediately rejected on the basis of i n s u f f i c i e n t data above detection l i m i t s ( c f . Table 5-3). Titanium and gallium provided s u f f i c i e n t data, however, q u a l i t a t i v e l y , these elements appear randomly d i s t r i b u t e d throughout the region. Furthermore no techniques of determining s i g n i f i c a n t populations could be applied due to the l i m i t a -tions previously placed on the a p p l i c a t i o n of the emission spectrographic r e s u l t s (section 3.5). Antimony, chromium, and t i n were detected i n a s u f f i c i e n t l y large number of deposits (Table 5-3) to allow study of t h e i r d i s t r i b u t i o n on the basis of presence versus absence i n detectable q u a n t i t i e s ; meaningful d i s t r i b u t i o n s were revealed. Antimony, found i n only 10 deposits, showed a marked concentration i n the Wernecke Mountains and around the periphery of the Selwyn Basin (Figure 5-18). Only one deposit with detectable antimony i s i n the region character-ized by deposits with undetectable antimony. This simple pattern bears a remarkable s i m i l a r i t y to the previously established patterns. Chromium was detected i n samples from 27 deposits (Figure 5-l§). F i f t e e n of the remaining 17 deposits define a non-detected chromium trend, centered on the Backbone Ranges and flanked by deposits containing detectable chromium. The s i m i l a r i t y to previously established regional patterns i s d i s t i n c t . Tin, detected i n 27 deposits, i s concentrated along the northeastern flank of the Backbone Ranges and i n the Wernecke Mountains (Figure 5-20). Other deposits with detectable quantities are scattered p e r i p h e r a l l y around the Selwyn Basin. Deposits with no detectable t i n follow a b e l t through the ce n t r a l Backbone Ranges and occur i n the western and northwestern reaches of Figure 5-20. Although s l i g h t l y more i r r e g u l a r , the t i n pattern i s s i m i l a r FIGURE 5-18: GEOGRAPHIC DISTRIBUTION OF ANTIMONY IN SPHALERITE ©Antimony detected V Antimony not detected S t i p p l e d area denotes the extent of sphaleri t e s with undetected antimony. ( A n a l y t i c a l r e s u l t s f o r 44 locations only) FIGURE 5-19: GEOGRAPHIC DISTRIBUTION OF CHROMIUM IN SPHALERITE ©Chromium detected • Chromium not detected St i p p l e d area denotes the extent of sp h a l e r i t e s with undetected chromium. ( A n a l y t i c a l r e s u l t s for 44 locations only) FIGURE 5-20: GEOGRAPHIC DISTRIBUTION OF TIN IN SPHALERITE @ T i n detected V T i n not detected S t i p p l e d area denotes the extent of sphalerites with undetected t i n . ( A n a l y t i c a l r e s u l t s f o r 44 locations only) 132 to other established regional trends. Summary Patterns established i n Figures 5-11'through 5-16 and 5-18 through 5-20 demonstrate a remarkable s i m i l a r i t y i n the geographic d i s t r i b u t i o n of the nine elements considered. Furthermore the d i s t r i b u t i o n of host rock ages (Figure 5-3) also c l o s e l y conforms to element d i s t r i b u t i o n trends, thereby suggesting a fundamental r e l a t i o n s h i p between bimodal element data and host rock age categories. Implications of this r e l a t i o n s h i p , i n terms of regional metallogeny, are discussed i n Chapter 6. 5.4 Comparison of Minor Element Contents i n Sphalerite from the Northern  C o r d i l l e r a with Other Areas arid Types of M i n e r a l i z a t i o n The minor constituents determined i n s p h a l e r i t e from the northern c o r d i l l e r a are most comparable to published analyses a v a i l a b l e f o r other carbonate hosted ( M i s s i s s i p p i V a l l e y type) zinc-lead deposits (Evans et a l . , 1968; Sangster and Li b e r t y , 1971; H a l l and Heyl, 1968) . Marked contrasts can be seen between the a n a l y t i c a l r e s u l t s obtained i n th i s study and those obtained from sphale r i t e s from d i f f e r e n t types of s p h a l e r i t e m i n e r a l i z a t i o n ( i . e . hydrothermal veins, volcanogenic deposits, e t c . ) , including one study on s p h a l e r i t e from a nearby Yukon l o c a t i o n (Boyle and Jambor, 1963, examined the minor element content of sp h a l e r i t e from s i l v e r - r i c h lead-zinc veins from Keno H i l l , 100 km south of the Wernecke Mountains). The r e s u l t s of these reports are tabulated f o r comparison i n Table 5-7. A mean a n a l y t i c a l r e s u l t and standard deviation were calculated for any quantitative data published and these are l i s t e d below s i m i l a r c a l c u l a t i o n s derived from data TABLE 5-7 TABULATION OF MEAN ANALYTICAL VALUES OF MINOR ELEMENTS IN SPHALERITE FROM DIFFERENT LOCATIONS AND TYPES OF DEPOSITS Elements Author Location Type of Number of Mean A n a l y t i c a l Value and Standard Deviation ( i n brackets) M i n e r a l i z a t i o n Samples Ag Cd Co Cu Fe Mn Ni Pb He This thesis Northern C o r d i l l e r a Stratabound 166 13 1780 3.3 172 2570 30 0.7 644 & 33 (30) (904) (12) (312) (3815) (34) (5.7) (1274) (64) Al .Similar types of min e r a l i z a t i o n Evans et a l . , 1968 Western Canada Stratabound 20 1800 _ _ 23265 353 - (769) - - (11040) (266) - - -Sangster and Li b e r t y , Ontario Stratabound 12 2.0 2205 <6 5.7 5464 19 4.5 80 1971 (1.0) (470) - (3.8) (3320) (6.4) (0.6) (100) -H a l l and Heyl, 1968 Upper M i s s i s s i p p i Stratabound 6 21 1678 15.3 75 14133 48 <4 Valley D i s t r i c t (17) (1321) (8.9) (58) (17150) (55) - -ii II Illinois-Kentucky Stratabound 5 5 6860 11.2 _ 25100 6 _ _ F l u o r i t e - D i s t r i c t (6.7) (4130) (10.0) - (24115) (8) - - _ J o l l y and Heyl, 1968 Upper M i s s i s s i p p i Stratabound 7 _ _ _ _ _ 0.36 Valley D i s t r i c t - - - - - - - - (0.33) II ,) East Tennessee Stratabound 9 _ _ _ _ (1.1) D i s t r i c t - - . - - - - - - (2.2) Jonasson and Sangster, A l l Canada Stratabound 18 _ _ _ _ 3.7 1974 locations - - - - - ' - - - • 7.5 B] Si m i l a r l o c a t i o n Boyle and Jambor, 1963 Yukon Vein 10 1100 8540 <10 1360 55080 1500 <20 360 (2060) (1360) - (2100) (31100) (2430) - (310) -C] Other locations and types of mineralization Nash, 1975 Utah Vein 7 49 3715 _ 2310 26280 2186 600 (36) (380) - (1120) (5730) (1145) - (650) -Nishiyama, 1974 Japan Kuroko-type 12 53 • 3433 6.6 _ 3090 293 22 13.8 (50) (1926) (6) - (928) (234) (ID - (15.8) Halfon and Rosique, France Vein 9 634 1961 33 2445 265 8.5 1976 (285) (448) (17) (555) - (271) (8.5) - -II II II Stratiform " 317 2264 13.6 1528 _ 1307 15.6 1646 (341) (527) (8) (637) - (1243) (10) (1803) -Rose, 1967 New Mexico, Central Variable 130 23.5 1439 223 _ _ 3700 9.5 Mining D i s t r i c t (41.5) (452) (187) - - (2595) (7.2) - -Utah, Bingham 57 29 3415 2.5 3610 6.7 _ Mining D i s t r i c t (39) (625) (1.9) - - (1990) (9) - -(- - not determined: values of 0 ppm are substituted f o r non-detected resu l t s i n mean and standard deviation calculations) 134 i n t h i s study. D i r e c t comparisons are not always p r a c t i c a l because the minor element s u i t e determined, the a n a l y t i c a l techniques used, and the number of samples analyzed a l l vary considerably. Furthermore, most studies deal with a s p e c i f i c deposit or mining d i s t r i c t , which tends to be much smaller than the area dealt with i n t h i s study, hence the data from the northern c o r d i l l e r a might be expected to vary more than other published r e s u l t s . I t i s u s e f u l however, to b r i e f l y survey the r e s u l t s of other studies r e l a t i v e to those of this thesis i n order to determine the uniqueness of the s p h a l e r i t e from the northern c o r d i l l e r a . Therefore, Table 5-7 defines some of the variables from each study ( l o c a t i o n , type of deposit, number of samples analyzed, a n a l y t i c a l standard deviation about the mean value calculated) to permit q u a l i f i c a t i o n s on the comparison of the data. Relative to reported minor element contents i n s p h a l e r i t e f o r other carbonate hosted zinc-lead deposits, the sphal e r i t e s of the northern c o r d i l -l e r a are low i n i r o n content and are high i n copper, lead and mercury contents ( l i t t l e data i s a v a i l a b l e regarding lead and mercury contents, hence t h i s comparison i s uncertain). S i l v e r , cadmium, cobalt, manganese, and n i c k e l concentrations allv:tend to f a l l w ithin the range of reported values fo r these elements i n s p h a l e r i t e from other areas . Iron contents e x h i b i t the strongest contrast, being almost an order of magnitude below those reported for more southerly parts of western Canada (Evans et a l . , 1968) or for the Illinois-Kentucky f l u o r i t e d i s t r i c t i n the M i s s i s s i p p i V a l l e y (Hall and Heyl, 1968) . Mercury contents i n s p h a l e r i t e from the Upper M i s s i s s i p p i Valley d i s t r i c t and from the Eastern Tennessee d i s t r i c t ( J o l l y and Heyl, 1968) are d i s t i n c t l y lower than those determined f o r the northern c o r d i l l e r a . Sphalerite i n vein lodes from c e n t r a l Kentucky and from c e n t r a l Tennessee ( J o l l y and Heyl, i b i d . ) appears to contain concentrations of mercury comparable to those from the stratabound s p h a l e r i t e from the northern c o r d i l l e r a , 135 however, d i f f e r i n g a n a l y t i c a l techniques make t h i s comparison d i f f i c u l t . The mercury contents i n s p h a l e r i t e from the northern c o r d i l l e r a are high r e l a t i v e to those quoted for other regions i n Canada with carbonate-hosted zinc-lead deposits (Jonasson and Sangster, 1974) . The northern c o r d i l l e r a n s p h a l e r i t e mean value i s approximately two orders of magnitude greater than that derived from f i v e deposits i n the Pine Point D i s t r i c t but i s only double the r e s u l t from three deposits i n B r i t i s h Columbia; none of the areas discussed (Jonasson and Sangster, i b i d . ) display the range i n concentrations determined for the northern c o r d i l l e r a . I t i s i n t e r e s t i n g to note that Jonasson and Sangster l i s t one deposit ( P r a i r i e Creek) i n the Mackenzie Mountains which provided a mean value (based on only two samples) of 933 ppm; t h i s i s s i g n i f i c a n t l y higher than any other Canadian deposits discussed by them and i s three times the highest value determined i n th i s report. Sphalerite taken from vein lodes at Keno H i l l i n the cent r a l Yukon (Boyle and Jambor, 1963) i s markedly enriched i n s i l v e r , cadmium, copper, iron, and manganese r e l a t i v e to the carbonate hosted m i n e r a l i z a t i o n 100 to 200 km to the north or east. Other vein occurrences of s p h a l e r i t e (Nash, 1975; Halfon and Rosique, 1976) also record high copper and i r o n contents, however they i l l u s t r a t e the v a r i a b i l i t y found i n some elements (e.g. s i l v e r , cadmium, manganese; Table 5-7) thereby suggesting that the type of mineral-i z a t i o n i s not nec e s s a r i l y a dominant f a c t o r i n c o n t r o l l i n g minor element contents of s p h a l e r i t e . Similar conclusions can be drawn from a study on sph a l e r i t e i n Kuroko type deposits (Nishiyama, 1976) and from a broad study encompassing various types of min e r a l i z a t i o n i n two mining d i s t r i c t s of the southwestern U.S.A. (Rose, 1967)(cf. Table 5-7). 136 5.5 Colouration i n Sphalerite from the Northern C o r d i l l e r a Colouration i n minerals i s most often a t t r i b u t e d to the presence of t r a n s i t i o n metals orlanthanide elements a f f e c t i n g the valence electrons i n the c r y s t a l structure (Burns, 1970). Absorption of s p e c i f i c r a d i a t i o n bands i n the v i s i b l e region of the electromagnetic spectrum by these valence electrons r e s u l t s i n colouration of transmitted l i g h t . C r y s t a l l i n e s p h a l e r i t e commonly contains a v a r i e t y of t r a n s i t i o n metals and exhibits a considerable range of colours, from black and dark amber shades, through paler amber, yellow, orange, and red shades, to green, purple and colourless tones. The trend of colouration from dark to pale o r i g i n a l l y was thought to r e f l e c t a decreasing content of i r o n (Palache et a l . , 1944). More recent analyses however (discussed below);, have questioned the d e t a i l e d c o r r e l a t i o n of high i r o n contents to dark colours i n s p h a l e r i t e . Roedder and Dwornik (1968) investigated d i s t i n c t colour banding i n s p h a l e r i t e from the Pine Point D i s t r i c t and concluded that 1) the i r o n contents were r e l a t i v e l y low o v e r a l l (from 0.3 to 2.5 weight percent), and 2) i r o n contents did vary with banding but could not be r e l a t e d to colouration of the bands. A f t e r considering alternate causes f o r the colour bands, such as organic content, 'radiation s e n s i t i v e colour centres', and deviation from pure ZnS stoichiometry, the authors could o f f e r no v e r i f i e d a l t e r n a t e explanation. Graeser (1969) confirmed ;the lack of c o r r e l a t i o n of i r o n content with colour f o r s p h a l e r i t e samples from Binnatal, Switzerland, however he deter-mined a r e l a t i o n between manganese content and colour (Figure 5-21). In t h i s case a l l of the darker brown and 'black' sphalerite samples contained more than 100 ppm manganese. Even though only 12 samples were studied and the t o t a l range of manganese contents was r e l a t i v e l y small (less than one 137 order of magnitude) the 100 ppm manganese level did provide an effective threshold value for segregating colours. Nishiyama (1975) also discounted iron as the cause of dark colour i n sphalerite from a kuroko-type deposit in ppm 10000 1000-i 100 J s i s a a ' S a B R B . S a • 2 a. a a a a a a a a j j j F e / . Cd Cu - O Mn y ,n \ Go. • O O O 0) O O O FIGURE 5-21 O © DISTRIBUTION OF SOME MINOR ELEMENTS RELATIVE TO COLOUR IN SPHALERITE FROM BINNATAL, SWITZERLAND (after Graesner, 1969) Colour Index: 0 yellow to brown-yellow 9 brown • dark brown to black Japan. Here the lowest iron analysis (0.18 weight percent) came from black sphalerite, whereas analyses (0.33 weight percent) greater than the mean iron content were obtained from yellow-brown sphalerite. Even though the above papers demonstrate a lack of detailed correlation between i r o n and colour, a number of reports have noted a general 'Sympathetic variation between iron (and commonly manganese) contents i n sphalerite and colouration (Bradbury, 1961; Sims and Barton, 1961; Evans et a l . , 1968; and 138 Nash, 1975) . A s i m i l a r statement can be made for the sp h a l e r i t e samples of the northern c o r d i l l e r a . Colours found i n sp h a l e r i t e from the northern c o r d i l l e r a include black, dark amber, yellow, b r i g h t orange, green, co l o u r l e s s , and many intermediate and mottled shades of these colours. In order to s i m p l i f y the colour v a r i a b l e the 166 samples analyzed i n th i s study were coded into f i v e colour categories as follows: 1) dark amber, 2) pale amber or yellow, 3) orange, 4) green, and 5) mottled or intermediate tones. A t o t a l of 100 samples could be c l a s s i f i e d unambiguously i n the f i r s t four categories d e f i n i n g d i s t i n c t colours and the minor element analyses f o r these samples were studied to in v e s t i g a t e element d i s t r i b u t i o n s r e l a t i v e to colouration. An analysis of variance i n v o l v i n g 10 samples i n each of the four colour categories was performed (Appendix C; Table C-4) and indicated that at the 95 percent confidence l e v e l that the data v a r i a b i l i t y within each colour group was s i g n i f i c a n t l y d i f f e r e n t than the v a r i a b i l i t y between colour groups for s i l v e r , copper, i r o n , and manganese (Table C-4, a,c,d,e). Within group va r i a t i o n s of cadmium, lead, and mercury contents could not be distinguished from the between group v a r i a t i o n s (Table C-4, b,f,g) . Cobalt and n i c k e l variances could not be evaluated i n t h i s method due to low abundances and many undetected values f o r these elements. Mean values were then calculated f o r s i l v e r , copper, i r o n , and manganese; these mean values are tabulated i n Table 5-8 and are gr a p h i c a l l y displayed i n Figure 5-22. Figure 5-22 demonstrates that the trend i n colour from dark amber to pale amber i s accompanied by a d i s t i n c t decrease i n concentration f o r each element. The steep slopes of the trends f o r copper, i r o n , and manganese h i g h l i g h t t h i s r e l a t i o n s h i p best. I f th i s consideration i s extended to orange colours, since these are of a s i m i l a r hue to the amber and yellow shades above, i r o n decreases even further i n concentration. However, copper, 139 SO 01 100 50 10 •--^Si lver — •©Copper Iron (*io) ^ ^Manganese DARK AMBER PALE AMBER ORANGE FIGURE 5-22 GREEN PLOT OF COLOUR VERSUS MEAN ANALYTICAL VALUE FOR FOUR ELEMENTS Error bars denote the standard error of the mean for each value. 140 TABLE 5-8 MEAN ANALYTICAL RESULTS OF SOME ELEMENTS FOR FOUR COLOUR GROUPS IN SPHALERITE (quoted i n ppm; the standard error of the mean i s given i n brackets) Element Dark Amber Pale Amber Orange Green S i l v e r 20 12 19 1.2 (3) . (5) (7) (0.4) Copper 293 35 167 49 (43) (13) (75) (12) Iron 5500 2212 951 1569 (900) (710) (285) (250) Manganese 42 12 45 15 (6) (4) (10) (3) Number of Analyses 44 13 24 19 s i l v e r , and manganese a l l show a d i s t i n c t increase i n concentration i n orange sph a l e r i t e r e l a t i v e to the pale amber and green colours; enrichment i n these elements, coupled with a depletion of i r o n , might be responsible f o r the intense orange colours observed (based only on the elements from which a n a l y t i c a l r e s u l t s are a v a i l a b l e ) . In the case of the green coloured s p h a l e r i t e i t i s i n t e r e s t i n g to note that Figure 5-22 displays that copper, s i l v e r , and manganese decrease i n concentration r e l a t i v e to orange s p h a l e r i t e , whereas i r o n increases i n con-centration. This i s the opposite trend to that discussed above, however, the s i g n i f i c a n c e of th i s remains unknown since the mean a n a l y t i c a l values a t t r i b u t e d to the green s p h a l e r i t e tend to f a l l i nto an intermediate p o s i t i o n of absolute value f o r most elements. Only s i l v e r i s d i s t i n c t i v e i n the green category since i t i s an order of magnitude lower i n concentration i n green s p h a l e r i t e than i n any other colour investigated. One p a r t i c u l a r hand specimen of i n t e r e s t (number 20023t-127) consisted of dis c r e t e grains of b r i g h t orange s p h a l e r i t e intergrown with pale green to 141 colourless s p h a l e r i t e . In polished section, these grains were impossible to di s t i n g u i s h i n p l a i n l i g h t and appeared to have p r e c i p i t a t e d during the same mineralizing episode (Appendix A). The i n d i v i d u a l grains were s u f f i c i e n t l y large and pure to permit i n d i v i d u a l separation of the two colours from the same hand specimen; these two colours were then treated as independent samples from deposit number 20023 and the a n a l y t i c a l r e s u l t s are recorded as samples 20023-127 (bright orange) and 20023-128 (pale green to colourless) i n Tables 3-6 and 3-7. These r e s u l t s are plotted together i n Figure 5-23 and ex h i b i t a d i s t i n c t l y s i m i l a r trend i n minor element concentrations f o r each colour. With the exception of n i c k e l , cadmium, and cobalt r e s u l t s (which are equal f o r each colour), the green s p h a l e r i t e i s s l i g h t l y enriched i n each element r e l a t i v e to the orange s p h a l e r i t e . This trend f o r t h i s p a r t i c u l a r specimen i s contrary to the trend established above of s i l v e r , copper, and manganese being found i n greater concentrations i n orange s p h a l e r i t e than i n green. Therefore the p o s s i b i l i t y of s i l v e r , copper, and manganese being r e l a t e d to in t e n s i t y of orange colour, as suggested above, does not seem l i k e l y . The d i r e c t v a r i a t i o n of i r o n content with darkness of colour cannot be confirmed i n t h i s study. Compared to other areas the s p h a l e r i t e specimens from the northern c o r d i l l e r a tend to be iron-poor (Table 5-7), yet numerous dark amber to black specimens are present. A l l seven samples recording over one weight percent i r o n (Table 3-7) are very dark i n colour, but the i r o n contents f o r dark amber s p h a l e r i t e are as'low as 120 ppm (sample number IOOIO7OI) . However, the dominant feature displayed i n Figure 5-22 i s that the darkest s p h a l e r i t e samples are consistently enriched i n minor elements r e l a t i v e to the paler colours. Therefore only a sympathetic r e l a t i o n s h i p between higher i r o n content, and perhaps higher copper content, with darker colouration i n s p h a l e r i t e can be confirmed. The foregoing discussion has considered colouration i n s p h a l e r i t e PLOT OF MINOR ELEMENT CONTENTS OF CO-EXISTING GREEN AND ORANGE SPHALERITE GRAINS (Cd values * 10) 143 purely on a q u a l i t a t i v e l e v e l . Q u a n t i f i c a t i o n of colouring agents might be attempted through measurement of the absorption spectra of the s p h a l e r i t e specimens, however such a project i s outside the scope of t h i s t h e s i s . Absorption spectra can be used to i d e n t i f y oxidation states and co-ordination symmetries of a t r a n s i t i o n metal ion held within the s p h a l e r i t e structure and can be r e l a t e d to energy l e v e l t r a n s i t i o n s of that ion ( c f . Burns, 1970, p. 53). When these t r a n s i t i o n energies coincide with the energy of a s p e c i f i c wave-length (colour) of l i g h t , that colour of l i g h t i s absorbed whereas the remaining l i g h t i s transmitted and gives the mineral colour. In this.way possible colouring agents can be defined and i n t e n s i t i e s of a s p e c i f i c colour can be equated to concentrations of the colouring agent. Absorption spectra can also be used to define energy t r a n s i t i o n s r e l a t e d to vacancies or defects i n a structure (ca l l e d colour centres) caused by deviations from s t o i c h i o -metry or by i n c l u s i o n of i n t e r s t i t i a l atoms. Selective absorption of parts of the v i s i b l e spectrum by e l e c t r o n i c t r a n s i t i o n s i n these imperfections might produce s p e c i f i c colours i n minerals (Lehmann and Bambauer, 1973). Therefore an i n v e s t i g a t i o n of the absorption spectra of the 100 s p h a l e r i t e specimens discussed e a r l i e r i n t h i s section might provide a stronger basis for i n t e r p r e t i n g the cause and i n t e n s i t y of the observed colours. A discussion of four theories on the o r i g i n of colour i n minerals has been published a f t e r the completion of this text. These theories compliment each other i n attempting to explain :the r e l a t i o n of colour to the range of i n t e r a c t i o n s and c h a r a c t e r i s t i c s possible for the valence electrons present i n mineral structures. The reference i s included here to complete the above discussion. Reference: Nassau, Kurt, 1978. The o r i g i n s of colour i n minerals; Amer. Mineral., Vol. 63, pp. 219-229. 144 CHAPTER 6: INTERPRETATIONS, CONCLUSIONS, AND SUGGESTIONS FOR FURTHER RESEARCH 6.1 Interpretations and Discussion: Implications for Metalldgenesis Metal d i s t r i b u t i o n patterns outlined i n Chapter 5 (Figures 5-11 through 5-20) define prominent bimodal d i s t r i b u t i o n s which c l o s e l y p a r a l l e l the dominant carbonate depositional axis along the Mackenzie Arch and the d i s t r i -bution of host rock age groups (Figure 5-3). This r e l a t i o n s h i p h i g h l i g h t s l i t h o s t r a t i g r a p h i c and time-stratigraphic influences on regional metallogeny. However, the dominant tectonic c o n t r o l over mineral deposition, as indicated by geologic descriptions of deposits (Appendix A) and by the occurrence of s p h a l e r i t e mainly i n breccias, veins, and f r a c t u r e f i l l i n g s (Figure 5-5), indicates that s t r u c t u r a l considerations are also important. In l i g h t of the previous discussion on the p o t e n t i a l f o r zinc-lead m i n e r a l i z a t i o n i n the northern c o r d i l l e r a ( section 4.4), two d i f f e r e n t i n t e r p r e t a t i o n s seem to p l a u s i b l y account f o r the d i s t r i b u t i o n of minor elements, host rock ages, and character of m i n e r a l i z a t i o n outlined i n t h i s t h e s i s . These are: 1] the regional m i n e r a l i z a t i o n occurred during a s i n g l e metallogenic event where the present minor element d i s t r i b u t i o n r e f l e c t s a zonation i n concentrations from 'enriched' to 'depleted' areas, and 2] the bimodal d i s t r i b u t i o n s determined for most of the elements r e f l e c t two unique sources of metals and developed i n response to two independent metallogenic events of d i f f e r e n t ages. In the following d i s c u s s i o n i t w i l l become apparent that the f i r s t i n t e r p r e t a t i o n explains inadequately the data presented. Two independent metallogenic events, however, can be defined and these appear to have produced the carbonate-hosted zinc-lead mineral deposits i n the northern c o r d i l l e r a . M i n e r a l i z a t i o n formed during a s i n g l e metallogenic event might have 145 developed a regional zonation i n minor element contents i n s p h a l e r i t e through a gradual depletion of elements from mineralizing solutions as they progress away from the metal-rich source beds. S t r u c t u r a l c o n t r o l over m i n e r a l i z a t i o n suggests major f a u l t s could have diverted mineralizing solutions i n t o s p e c i f i c areas, thereby enhancing development of minor element 'enriched' and 'depleted' regions. Such a process of s t r u c t u r a l l y c o n t r o l l e d f l u i d migration i s supported i n the northern c o r d i l l e r a by the mineralogic r e l a t i o n s determined i n Appendix A, and by the positions of major f a u l t s (Hess, Knorr, Plateau, etc.) r e l a t i v e to source areas (Figure 6-1) and to d i s t r i b u t i o n s of minor element populations. Regional zonations i n minor element concentrations, such as suggested by the 'combined metal' contents (Figure 5-17), are however, not gradational i n i n d i v i d u a l d i s t r i b u t i o n patterns f o r each element; population boundaries are w e l l defined and do not support a gradual depletion of minor elements from s t r a t a f u g i c s o l u t i o n s . Furthermore, zones of ' p a r t i a l l y enriched' s p h a l e r i t e , developed through migration of f l u i d s along j o i n t planes peripheral to f a u l t s , are not observed i n metal d i s t r i b u t i o n s . Ordovician, S i l u r i a n , and Devonian rocks i n thrust s l i c e s commonly bear minor element patterns i n s p h a l e r i t e of d i s t i n c t l y d i f f e r e n t character than those i n the adjacent Proterozoic and Lower Cambrian rocks. A simple explanation to t h i s i s that the thrust f a u l t s are exposing s t r a t i g r a p h i c sections containing m i n e r a l i z a t i o n which was p r e f e r e n t i a l l y formed wi t h i n the two age groups through independent processes at d i f f e r e n t times. Consideration of t h i s i n t e r p r e t a t i o n leads to a more convincing explanation, below, of the minor element d i s t r i b u t i o n character-i s t i c s . D i s t r i b u t i o n of s p h a l e r i t e deposits:; i n the northern c o r d i l l e r a i s dominated by host rocks of two d i s t i n c t age groups separated by a r e l a t i v e l y 'barren' horizon (Figure 5-2). The r e l a t i o n s h i p between bimodal element ON FIGURE 6-1: STRUCTURALLY CONTROLLED MIGRATION PATHS FOR DEWATERING BASINAL SOLUTIONS Metal-rich brines dewatering from the Selwyn Basin G&O or the Richardson Trough (^) might have been diverted along major f a u l t s (—4—) to produce a region of s p h a l e r i t e 'depleted' i n minor elements (generally outlined by the s t i p p l e d area). 147 d i s t r i b u t i o n s and the d i s t r i b u t i o n of host rock ages i s further i l l u s t r a t e d i n Figure 6-2. In t h i s figure the 'depleted' population for most elements i s consistently centered on and extends beyond the l i m i t s of the Ordovidian, S i l u r i a n , and Devonian host rock d i s t r i b u t i o n , whereas the 'enriched' popula-t i o n f o r each element r a r e l y extends into the area of younger hosts . This pattern suggests that an event leading to m i n e r a l i z a t i o n i n Ordovician to Devonian rocks was concentrated i n these units i n the Backbone Ranges, but extended into adjacent Proterozoic and Lower Cambrian u n i t s . Conversely, a mineralizing episode a f f e c t i n g the Proterozoic and Lower Cambrian rocks was r e s t r i c t e d to these older units"'", most probably because i t occurred p r i o r to deposition of the younger hosts. Therefore, the r e l a t i o n s h i p of minor element d i s t r i b u t i o n patterns and host rock age groups i s best explained by two metallogenic events of s i g n i f -i c a n t l y d i f f e r e n t ages; one of these defines a pre-Franklin Mountain Formation metallogenic event and the other defines a post-Franklin Mountain Formation event. The age of the younger event i s presumably Late Devonian or l a t e r since the youngest rocks affected are Upper Devonian. The age of the miner-a l i z i n g episode a f f e c t i n g the Proterozoic and Lower Cambrian rocks appears to be Middle to Late Cambrian, that i s , p r i o r to deposition of p o t e n t i a l hosts i n the F r a n k l i n Mountain Formation (see Figures 5-2 and 5-5). M i n e r a l i z i n g solutions which led to s p h a l e r i t e p r e c i p i t a t i o n during the Middle to Late Cambrian were r e l a t i v e l y enriched i n minor elements and reached much of the carbonate terrane developed by Late Cambrian time. P o t e n t i a l "*" D i s t r i b u t i o n of copper (Figure 5-13) reveals the discussed overlap of depleted values into the older hosts along the southwest flank of the trend; however, on the northeast flank, enriched values co n s i s t e n t l y overlap the younger deposits. I t i s i n t e r e s t i n g to note that the copper-enriched Red-stone Formation extends through t h i s area; s p e c u l a t i v e l y , t h i s formation possibly supplemented the copper i n the mineralizing solutions which then caused extra enrichment of copper i n s p h a l e r i t e along the northeast flank of the trend. CO FIGURE 6.-2: DISTRIBUTION OF ORDOVICIAN TO DEVONIAN AGED HOST ROCKS RELATIVE TO 'DEPLETED' POPULATIONS OF FOUR ELEMENTS Sti p p l e d area o u t l i n e s the Ordovician to Devonian host d i s t r i b u t i o n . Crosses ind i c a t e deposit l o c a t i o n s . 'Depleted'population d i s t r i b u t i o n s are displayed as: S i l v e r , • • • • C o b a l t , Iron, and ~ Mercury. 149 sources for these solutions cannot be confidently defined because l i k e l y b a s i n a l source regions f o r metal-rich brines have not been documented i n the regional Proterozoic or Cambrian stratigraphy. C e c i l e (1978, pers. comm.) suspects that an extensive shale basin was present during the Proterozoic and was the precursor to the younger Selwyn Basin. Proterozoic shales, u p l i f t e d along thrust f a u l t s , are known near the Gayna River deposit (number 20024) and suggest a p o s s i b l e metal source basinward (Figure 6-3) to the southwest (Hewton, R.S., 1978-, pers. comm.). However, these units do not outcrop i n the Selwyn Basin area and c o r r e l a t i o n s with other Proterozoic e l a s t i c s are uncertain. Middle to Late Cambrian paleophysiography strongly suggests the possib-i l i t y that k a r s t i c processes were active adjacent to the Mackenzie Arch (Figure 6-3) . Most of the Middle Cambrian u n i t s were removed during a major period of u p l i f t and erosion p r i o r to F r a n k l i n Mountain Formation deposition i n the Upper Cambrian. Lack of known deposits i n the c r e s t a l regions of the present Mackenzie Arch might be due to 1) less promising host l i t h o l o g i e s i n t h i s area (note the arenaceous nature of the Katherine Formation i n Figure 6-2), or 2) active d i s s o l u t i o n i n t h i s area and transportation of f l u i d s to the south and west where s o l u t i o n b r e c c i a t i o n associated with k a r s t i n g developed s p h a l e r i t e and galena m i n e r a l i z a t i o n (as at Gayna River, number 20024, or Goz Creek, number 10033; Brock, 1976). Bernard (1973) outlined a process whereby k a r s t i c c a v i t i e s below unconformity surfaces can c o l l e c t d e t r i t a l and chemical sediments (including sulphides) and can concentrate metals s u f f i c i e n t l y to produce zinc-lead m i n e r a l i z a t i o n . He proposes that d i s s o l u t i o n of carbonate rocks can provide s u f f i c i e n t metals to r e s u l t i n formation of s i z e a b l e sulphide deposits. Such a process has been considered for zinc deposits of east Tennessee ( Z u f f a r d i , 1976). Here, development of a mature karst system within the Lower Ordovician Mascot and Kingsport Formations and below an FIGURE 6-3: REGIONAL MINERALIZATION DUE TO TWO METALLOGENIC EVENTS Arrows i n d i c a t e p o s s i b l e metal sources and t r a n s p o r t a t i o n paths l e a d i n g to m i n e r a l i z a t i o n i n each age group: l a - k a r s t processes r e l a t e d to the sub-Upper Cambrian unconformity, lb - p o s s i b l e P r o t e r o z o i c shale b a s i n dewatering, 2 - Selwyn shale Basin dewatering. Diamonds represent schem-a t i c l o c a t i o n s of dep o s i t s s t u d i e d (as p r o j e c t e d on the time-space and c r o s s - s e c t i o n l i n e AB i n Figure 4-3; i n p a r t i c u l a r , the true r e l a t i o n between deposit l o c a t i o n s and the sub-Upper Cambrian unconformity i s unknown). See Figure 4-4 f o r c r o s s - s e c t i o n references. 151 unconformity, provided a su b s t a n t i a l sub-surface drainage system which was brecciated and p a r t i a l l y f i l l e d with sediment; brecciated channels i n the Kingsport Formation (underlying the Mascot Formation) are the prime hosts f o r zinc m i n e r a l i z a t i o n (Crawford and Hoagland, 1968) . The source of zinc however, could be "... the same low-grade, z i n c i f e r o u s , eroded Mascot Formation covering the Kingsport" ( Z u f f a r d i , 1976, p. 200) . Hence, k a r s t i c processes active i n the northern c o r d i l l e r a could have prepared the carbonate hosts and supplied metal-bearing solutions f o r zinc-lead m i n e r a l i z a t i o n during Middle to Late Cambrian u p l i f t and erosion of sediments on the Mackenzie Arch. The source of metals and solutions which produced zinc—lead m i n e r a l i z a -t i o n during the Late or post-Devonian i s probably the Selwyn Basin, as discussed previously (section 4.4). The Misty Creek Embayment, recently proposed by C e c i l e (1978a,b) adds further evidence that Ordovician to Devonian hosted deposits could be derived d i r e c t l y from metalliferous brines dewatering from the shale basin; t h i s source i s l i k e l y unique to t h i s metallogenic event. Carbonate-hosted deposits a t t r i b u t e d to t h i s event are l a t e r a l l y proximal to fa c i e s changes into shales of the Road River Formation and the 'Black C l a s t i c ' u nit (Figure 4-5); migration of s t r a t a f u g i c solutions, either l a t e r a l l y or up-dip along the Mackenzie Arch paleoslope, leads d i r e c t l y i n t o horizons now known to contain s p h a l e r i t e m i n e r a l i z a t i o n characterized by r e l a t i v e l y low minor element contents (Figure 6-3). Any f a u l t s or fractures i n these rocks would c o l l e c t the solutions and d i r e c t them into overlying carbonate horizons, including any adjacent Proterozoic or Lower Cambrian formations also cut by the f a u l t s . R e l a t i v e l y 'barren' F r a n k l i n Mountain Formation carbonates d i v i d i n g the two mineralized age groups remain unexplained i n d e t a i l i n t h i s study. In general, the l i t h o l o g i e s of t h i s u n i t do not appear any l e s s promising as hosts f o r mi n e r a l i z a t i o n than the younger formations; the F r a n k l i n Mountain 152 Formation i s commonly porous and contains traces of pyrobitumen s i m i l a r to mineralized formations, i n d i c a t i n g that p e t r o l i f e r o u s (and possibly metal-l i f e r o u s ) s olutions have traversed the formation (C e c i l e , 1978, pers. comm.). The shales of the Misty Creek Embayment were most extensive into the platformal carbonates during F r a n k l i n Mountain accumulation (Cecile, 1978a,b) and possibly r e s t r i c t e d carbonate accumulation at this time to a p o s i t i o n too high on the Mackenzie Arch paleoslbpe. Diversion of f l u i d s i n f a u l t zones to s t r a t i g r a p h i c a l l y overlying units might also have r e s t r i c t e d access of miner-a l i z i n g solutions into the F r a n k l i n Mountain Formation and mineralized only a r e s t r i c t e d zone immediately adjacent to the shales. Furthermore, the present d i s t r i b u t i o n of rocks of t h i s age i s highly r e s t r i c t e d i n the areas of most i n t e r e s t and outcrops dominantly occur within the r e p e t i t i v e sequence of Proterozoic and middle Paleozoic u n i t s d i r e c t l y east of the dominant trend of m i n e r a l i z a t i o n ( c f . regional geology map, Figure 4-2). I t i s i n t e r e s t i n g to note that volcanism appears to be associated with possible sources of metals for the younger event i n the Road River Formation (Cecile, 1978a,b) and i n the 'Black C l a s t i c ' u n i t (Dawson, 1977) i n the Selwyn Basin region. Volcanism and associated hydrothermal solutions mjight be expected to produce a greater enrichment of minor metal concentrations i n these source rocks, and thereby r e s u l t i n greater concentrations i n the s p h a l e r i t e produced from these sources. However, t h i s i s not the observed d i s t r i b u t i o n of concentrations. In the Northern O g i l v i e Mountains, deposits hosted i n Ordovician to S i l u r i a n aged carbonates, and therefore mineralized i n the younger event, are characterized by 'depleted' concentrations of minor elements (Figures 5-11, 12, 14, 15, 16, 18, 19, and 20),. yet they occur a considerable distance from any of the documented volcanism mentioned above. Furthermore, they are separated from the volcanism of the Selwyn Basin by Proterozoic and Lower Cambrian carbonate rocks bearing s p h a l e r i t e with 153 p a r t i c u l a r l y high minor element contents; t h i s m i n e r a l i z a t i o n has already been a t t r i b u t e d to the older metallogenic event. I t i s apparent from these patterns that no d i r e c t r e l a t i o n s h i p can be drawn between metals derived from middle Paleozoic volcanism i n the Selwyn Basin and metal contents i n sphal-e r i t e m i n e r a l i z a t i o n hosted i n rocks of the same age. The r e l a t i v e enrichment of s p h a l e r i t e deposited during the Middle to Late Cambrian metallogenic event w i l l remain unexplained i n d e t a i l u n t i l the sources and processes of mineral-i z a t i o n at that time are resolved. 6.2 Summary The model of m i n e r a l i z a t i o n proposed i n t h i s section attempts to define the regional metallogeny of carbonate-hosted zinc-lead deposits of the northern c o r d i l l e r a on the basis of 1) minor element d i s t r i b u t i o n s determined i n t h i s t h e s i s , 2) general geologic and mineralogic c h a r a c t e r i s t i c s of the mineralization, and 3) prevalent ideas concerning the genesis of stratabound carbonate-hosted zinc-lead m i n e r a l i z a t i o n . I n t e r p r e t a t i o n of the bimodal element d i s t r i b u t i o n s as representative of two d i s t i n c t metal sources f o r s p h a l e r i t e deposits of the northern c o r d i l -l e r a leads to the hypothesis that two independent processes of m i n e r a l i z a t i o n are the underlying cause. This hypothesis accounts f o r 1) two d i f f e r e n t populations f o r each minor constituent i n the s p h a l e r i t e , 2) two d i s t i n c t age groupings of rocks hosting the mi n e r a l i z a t i o n , 3) s p a t i a l r e l a t i o n s h i p s between minor element d i s t r i b u t i o n s and host rock d i s t r i b u t i o n s , 4) temporal r e l a t i o n s h i p s between the bimodal element d i s t r i b u t i o n s , the bimodal host age d i s t r i b u t i o n , and the 'barren' delineating horizon, and 5) geologic and mineralogic te x t u r a l c h a r a c t e r i s t i c s of the zinc-lead deposits. 154 Paleophysiography of the northern c o r d i l l e r a during the Middle to Late Cambrian suggests that k a r s t i c processes might have induced s p h a l e r i t e pre-c i p i t a t i o n at t h i s time, however other sources and processes must also be considered f o r m i n e r a l i z a t i o n of t h i s age. Regional physiographic features present during Late Devonian or l a t e r periods strongly suggest the younger episode of m i n e r a l i z a t i o n was derived from metal—rich solutions dewatering from the Selwyn Basin. The 'barren' nature of the F r a n k l i n Mountain Formation was p a r t i a l l y explained i n t h i s hypothesis, and the major uncon-formity beneath the F r a n k l i n Mountain dolomites i s a strong time-stratigraphic hiatus separating the rocks affected by each event; t h i s hiatus may have been an i n t e g r a l part of the early metallogenic event i f k a r s t i c processes r e l a t e d to the unconformity were s i g n i f i c a n t m i neralizing agents. The d i f f e r i n g sources of metals and processes of s p h a l e r i t e m i n e r a l i z a t i o n account for the d i f f e r i n g minor constituents; the d i f f e r i n g ages of metal-logenic events, accounts for the d i s t r i b u t i o n of s p h a l e r i t e occurrences i n two major host rock age groups and explains the temporal and s p a t i a l d i s t r i -bution of minor element patterns i n s p h a l e r i t e r e l a t i v e to these host rock ages. 6.3 Conclusions Following are the major conclusions of t h i s research concerning the character of s p h a l e r i t e m i n e r a l i z a t i o n i n the study area, drawn from i n t e r -p retation of a n a l y t i c a l r e s u l t s presented i n t h i s t h e s i s . In the carbonate rocks of the northern c o r d i l l e r a : 1] zinc-lead deposits can be i n d i v i d u a l l y characterized on the basis of minor element constituents i n s p h a l e r i t e , 155 2] two d i s t i n c t populations of zinc-lead deposits, as determined from minor element contents: i n s p h a l e r i t e , can be defined, 3] two major age groups of host rocks, separated by a pronounced unconformity-bounded and r e l a t i v e l y 'barren' age u n i t , contain the zinc—lead m i n e r a l i z a t i o n , 4] geographic d i s t r i b u t i o n s of minor element populations c o n s i s t e n t l y c o r r e l a t e with the geographic d i s t r i b u t i o n of host rock age groups, 5] a model of two independent processes of m i n e r a l i z a t i o n occurring during d i f f e r e n t ages and producing sphalerite containing d i f f e r e n t minor element assemblages best explains the character-i s t i c s of the mineralization, and 6] s p h a l e r i t e s contain high copper, lead, and mercury concentrations and low i r o n concentrations r e l a t i v e to other carbonate-hosted zinc—lead d i s t r i c t s i n North America. These r e s u l t s i n d i c a t e that a regional minor element study can be r e l a t i v e l y successful i n defining s p e c i f i c geochemical aspects of the m i n e r a l i z a t i o n of a broad area and can provide a s o l i d basis on which to interpret the general nature of the regional metallogeny. In the case of the northern c o r d i l l e r a , t h i s research project has provided s i g n i f i c a n t new data f o r a r e l a t i v e l y unexamined region and should stimulate further inves-ti g a t i o n s of the s p h a l e r i t e occurrences i n order to v e r i f y the i n t e r p r e t a -tions offered here. 6.4 Suggestions for Future Research Future research should be directed at further defining the sources of metals f o r , and the c h a r a c t e r i s t i c s of, the zinc—lead occurrences of the northern c o r d i l l e r a . Independent te s t s of the hypothesis that two periods of m i n e r a l i z a t i o n produced the s p h a l e r i t e deposits should be devised. The r e s u l t s obtained i n t h i s thesis suggest the following possible projects: 1] lead isotope analysis of as many galena samples as possible 156 from the deposits studied, i n order to define approximate ages and possibly metal sources for the zinc-lead m i n e r a l i z a t i o n (such a study i s presently i n progress i n the Department of Geological Sciences, U n i v e r s i t y of B r i t i s h Columbia), 2] sulphur isotope analysis of co-existing sulphide pairs could provide temperatures of formation of the deposits (this method has been applied to two deposits (Appendix A, Table A-2) but the r e s u l t s have, as yet, not been interpreted) and could provide a basis for i n t e r p r e t i n g a possible source for the , sulphur i n the sulphides ( i . e . biogenic versus magmatic sources, • c f . Evans et a l . , 1968), 3] minor constituent analysis of the shale source rocks and the carbonate host rocks from immediately adjacent to the m i n e r a l i -zation, immediately adjacent to the possible f l u i d conduits, and across the region as a whole, should be done i n order to further i n v e s t i g a t e the models of shale basin sources, k a r s t i c models, and possible f l u i d migration paths; these analyses might also test bimodal element d i s t r i b u t i o n patterns i n these rocks r e l a t i v e to age d i s t r i b u t i o n s , 4] a v a r i e t y of other s t a t i s t i c a l techniques (Q-mode f a c t o r analysis, trend surface analysis) might further define the basic bimodal element and host age d i s t r i b u t i o n s of the region as a whole, as w e l l as some of the more subtle v a r i a t i o n s (between samples or deposits) within each age group or within 'enriched' and 'depleted' minor element groups, and 5] a more q u a l i t a t i v e i n v e s t i g a t i o n into possible colouring agents i n these sphalerites might be attempted using the absorption spectra method outlined i n section 5.5, Unfortunately l i t t l e opportunity i s a v a i l a b l e to expand the specimen c o l l e c t i o n and therefore further define regional d i s t r i b u t i o n patterns, p a r t i c u l a r l y i n the northern and western areas; however continued i n v e s t i g a -t i o n using the specimens a v a i l a b l e within a n a l y t i c a l l i m i t a t i o n s outlined (as i n s e c t i o n 3.5) could provide a broader data base on which to b u i l d i n t e r p r e t a t i o n s of regional metallogeny, such as those proposed i n t h i s study. 157 BIBLIOGRAPHY Aitken, J.D., 1977. 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Handbook of strata-bound and s t r a t i f o r m ore deposits, V o l i 3, pp. 175-212. 166 APPENDIX A GEOLOGIC AND MINERALOGIC DESCRIPTIONS OF INDIVIDUAL DEPOSITS 167 APPENDIX A GEOLOGIC AND MINERALOGIC DESCRIPTIONS  OF INDIVIDUAL DEPOSITS Each deposit studied i s described i n the following point form format. Identity: Deposit number, deposit name. Geodata; Geologic information - any information a v a i l a b l e concerning the regional or l o c a l geology of the deposit i s recorded here - the sources of information used are: 1) data o r i g i n a l l y provided with the specimens 2) Northern C o r d i l l e r a n Mineral Inventory (Archer and Cathro, 1976) 3) any other published or unpublished reports a v a i l a b l e (the amount of information known tends to vary considerably from one deposit to another) Spec. Descr.: Specimen descriptions Hand: Hand specimen s u i t e - t h i s s ection includes an o v e r a l l d e s c r i p t i o n of a l l features v i s i b l e i n the hand specimens i n the c o l l e c t i o n (regardless of whether the specimen was used f or analysis or not) - also included are any features noted under the binocular microscope during the separation procedures Polished: Polished section descriptions (and sample numbers described) - one or two polished sections were selected from the specimens analyzed i n order to b r i e f l y determine the micro-mineralogic assemblages (and hence, any possible micro—contaminants) and to determine any paragenetic sequences v i s i b l e - photographic plates are included with some descriptions to i l l u s t r a t e s i g n i f i c a n t features Temp.: Temperature ind i c a t o r s - a l i m i t e d amount of f l u i d i n c l u s i o n homogenization temperature and sulphur isotope data i s a v a i l a b l e regarding t h i s c o l l e c t i o n (Godwin, C.I., 1977); t h i s data i s included where applicable and i s also summarized i n Table A - l . 168 Identity : 10006, Newt Geodata: - an Ordovician to S i l u r i a n aged dolomite (GSC unit 8, Road River Formation carbonate f a c i e s equivalent) hosts sp h a l e r i t e veins and tectonic b r e c c i a f i l l i n g s , with minor associated galena - l o c a l l y t h i s unit d i r e c t l y o v e r l i e s a Hadrynian, orange weathering dolomite u n i t i n t h i s area Spec. Descr. Hand: Polished: Temp .: the hand specimens range from massive galena with minor sphal-e r i t e , to massive sphalerite, or to brecciated dolomite host fragments within a sphalerite-sparry c a l c i t e matrix massive galena contains small randomly oriented i n c l u s i o n s of dark amber sp h a l e r i t e ; the galena i s somewhat f o l i a t e d and sheared and bears th i n oxidation coatings the massive, medium to coarse grained s p h a l e r i t e i s a dark amber colour, and except f o r l o c a l oxidation, i s e s s e n t i a l l y pure s p h a l e r i t e in'the breccia matrix i s intimately mixed with the sparry c a l c i t e and appears contemporaneous with i t two polished sections (10006-2, 10006-5), one each from massive and brecciated specimens, were studied the massive material proved e s s e n t i a l l y pure, with only l a t e stage sparry c a l c i t e v e i n l e t s cutting the s p h a l e r i t e the b r e c c i a matrix contains euhedral c a l c i t e rhombs as i n c l u -sions w i t h i n s p h a l e r i t e or as stringers through the s p h a l e r i t e ; the s p h a l e r i t e appears to have enclosed the c a l c i t e rhombs wi t h i n medium grained, euhedral c r y s t a l s , hence the s p h a l e r i t e i s formed a f t e r the c a l c i t e no other sulphides were seen the r e l a t i o n between the massive galena i n the hand specimens and the s p h a l e r i t e i s not seen i n the sections studied, there-fore a complete paragenesis i s unknown two sections with pseudo-secondary f l u i d i n c l u s i o n s provided homogenization temperatures of 125.9°C (10006-3) and of 131.5°C (10006-5) (Table A-l) Identity: 10010, Economic Geodata: - galena and sp h a l e r i t e , with barite-calcite-quartz-pyrobitumen veins, are found cutting the top of the Lower Cambrian Sekwi Formation - these veins appear to be emplaced along east s t r i k i n g fractures r e l a t e d to a northwest trending f a u l t system Spec. Descr.: Hand: - the host v e i n material i s a granular orange-weathering, w e l l fractured, ferro-dolomite which c a r r i e s disseminations and massive inc l u s i o n s of sulphides - sphalerite, of honey or dark amber colour, i s found as dissemin-ations or as coarse c r y s t a l l i n e fragments d i s t r i b u t e d through— 169 out the ve i n - a l t e r a t i o n to hydro z i n c i t e i s seen l o c a l l y - sparse to coarse disseminations of galena are common and can develop to massive lenses, apparently from the widest veins; galena also shows some oxidation rims - p y r i t e i s less common, occurring as trace disseminations through the ferrodolomite, and i s often accompanied by sphal-e r i t e or galena - specimen 10010-1 i s a brecciated material containing fragments of the host dolomite, sub-angular dark amber s p h a l e r i t e , f i n e euhedral galena cubes, and a l a t e stage sparry c a l c i t e - s p h a l e r i t e dominates the sulphides and occurs as i r r e g u l a r fragments f i l l i n g the gaps between sparry c a l c i t e c r y s t a l s - galena occurs i n minor q u a n t i t i e s , c l o s e l y associated with s p h a l e r i t e , or less commonly, i n f i l l i n g around c a l c i t e rhombs - the paragenetic sequence i s not displayed w e l l here and i s ac t u a l l y multi-stage and complex (Gibson, 1975) - f l u i d i n c l u s i o n homogenization temperatures from primary inc l u s i o n s i n s p h a l e r i t e yielded a r e s u l t of 152.0°C (10010-1) (Table A) 10020, Tart - galena, s p h a l e r i t e , and p y r i t e are hosted i n a H e l i k i a n dolo-mite - the sulphides, plus sparry c a l c i t e , form the matrix of a f a u l t b r e c c i a - the grey, f i n e grained dolomite host i s brecciated into angular fragments and cemented by medium to f i n e grained, c r y s t a l l i n e , brownish-red s p h a l e r i t e and white sparry c a l c i t e (Plate A-2) - a network of veins and stringers of matrix material includes' some dolomite host fragments - two core samples reveal p y r i t e v e i n l e t s one cm. wide i n a coarse sphalerite-sparry c a l c i t e matrix - galena i s rare in\the specimens obtained - s p h a l e r i t e , the dominant mineral i n specimen 10020—5, occurs as f i n e to medium sized, subhedral, grains, i n t e r l o c k i n g into massive accumulations; the colour grades from pale yellow to . deeper reddish-orange away from the host dolomite, i n d i c a t i n g possible successions of deposition or changing chemistry during p r e c i p i t a t i o n - p y r i t e forms i r r e g u l a r , fractured grains associated with the sp h a l e r i t e or as str i n g e r s through and around dolomitic host fragments - no other sulphides were observed - sparry c a l c i t e occurs throughout, intergrown with s p h a l e r i t e and as a f i n a l , open space f i l l i n g 170 - s p h a l e r i t e and p y r i t e appear to be contemporaneous and c a l c i t e developed during a middle to l a t e stage, hence the paragenesis i s : s p h a l e r i t e p y r i t e — c a l c i t e Identity: 10022, W i l l Geodata: - a f a u l t c o n t r o l l e d H e l i k i a n dolomite breccia has been i n f i l l e d with s p h a l e r i t e , galena, minor chalcopyrite, and sparry dolomite Spec. Descr.: Hand: - medium to f i n e grained, brown, s p h a l e r i t e , intimate with white coarse, sparry dolomite forms the matrix of a w e l l brecciated, m i c r i t i c grey dolomite host - l o c a l l y f i n e p y r i t e grains are present w i t h i n the matrix - l a t e stage dolomite v e i n l e t s cut across the b r e c c i a fragments and the matrix Polished: - polished s e c t i o n 10022-1 reveals the host dolomite bears much f i n e grained disseminated p y r i t e and some galena - the b r e c c i a i n f i l l i n g appears to be mainly a medium to coarse grained, c r y s t a l l i n e s p h a l e r i t e with f i n e i n c l u s i o n s of p y r i t e , galena and white, sparry dolomite - p y r i t e grains are subhedral and contemporaneous with the s p h a l e r i t e - galena forms anhedral grains and s t r i n g e r s , i n places cutting other sulphides, hence i s probably contemporaneous and s l i g h t l y l a t e r - ragged boundaries between s p h a l e r i t e and sparry dolomite, and inc l u s i o n s of one i n the other, suggest a contemporaneous formation. - l a t e stage white sparry dolomite v e i n l e t s cut both the breccia fragments and the matrix sulphides, and are l a t e r t e c t o n i c a l l y fractured - the paragenesis i s : s p h a l e r i t e p y r i t e galena dolomite Identity: 10024, Cominco A + 6 Geodata: - galena, p y r i t e , and s p h a l e r i t e are hosted i n Hadrynian carbon-ates close to the boundary of the overlying Cambrian carbonates - this l o c a t i o n i s only four miles to the north of l o c a t i o n 10025 Spec. Descr,.: Hand: - the host carbonate i s a grey-ferown, sucrosic dolomite with dark grey algal(?) bands which are l o c a l l y disrupted and o f f s e t 171 through b r e c c i a t i o n and i n f i l l i n g of s t r i n g e r s of sparry dolomite - the sulphides occur as t h i n veins along f r a c t u r e l i n e s or as b r e c c i a matrix f i l l i n g s - veins of f i n e grained s p h a l e r i t e with traces of f i n e grained p y r i t e extend into the brecciated areas - l o c a l l y , veins up to two cm. wide consist of coarse grained greenish-brown sphalerite, bearing d i s c r e t e coarse galena cubes - the b r e c c i a matrix i s mainly dark brown, medium to coarse grained sphalerite, with dense to sparse disseminations of p y r i t e , and i s followed by sparry dolomite Polished: - polished section 10024-2 i s a sample of b r e c c i a matrix material with large, angular, fractured grains of s p h a l e r i t e which i s apparently pure and forms an i n i t i a l paragenetic phase - i n f i l l i n g around the s p h a l e r i t e and through f r a c t u r e s i n i t , i s a coarse sparry dolomite bearing disseminated p y r i t e and traces of galena - paragenesis appears to be: s p h a l e r i t e p y r i t e galena dolomite Identity: 10035, Cominco BC + 5 Geddata: - s p h a l e r i t e and galena are hosted i n Hadrynian carbonates close to an overlying Cambrian carbonate Spec. Descr.: Hand: - the host carbonate i s a very coarsely brecciated, grey, . a l g a l l y ( ? ) laminated dolomite - coarse white sparry dolomite veins accompany c o a r s e l y c r y s t a l l i n e orange, and greenish-brown sphalerite as the dominant forms of mine r a l i z a t i o n ; the s p h a l e r i t e i s refractured, vuggy, and bears white oxidation coatings i n the vugs (smithsonite?) - s p h a l e r i t e also bears d i s c r e t e grains and s t r i n g e r s of galena and some disseminated p y r i t e - euhedral quartz c r y s t a l s and massive, i s o l a t e d , coarse c r y s t a l l i n e blebs of red-brown sph a l e r i t e form a l a t e stage, c o m p l e t e l y i i n f i l l i n g some vugs Polished: - a polished section (10025-1) of massive, orange, w e l l fractured s p h a l e r i t e with coarse galena inclusions was studied - the s p h a l e r i t e i s coarsely c r y s t a l l i n e with traces of f i n e grained p y r i t e and galena disseminated throughout - the s p h a l e r i t e i s well fractured and the f r a c t u r e l i n e s are f i l l e d with galena>pyrite>sparry dolomite - galena may form large blebs, perhaps i n f i l l i n g vugs i n s p h a l e r i t e and i t s e l f forming i n t e r n a l vugs which are p a r t i a l l y f i l l e d by bladed white c r y s t a l s (barite?) as a f i n a l stage - b r e c c i a t i o n of the dolomite host appears to be followed by a major s p h a l e r i t e phase bearing minor galena, p y r i t e , and sparry dolomite as an i n i t i a l paragenetic phase; t h i s was then 172 re-fractured and i n f i l l e d with galena, p y r i t e , and sparry dolomite followed by l o c a l b a r i t e ( ? ) p r e c i p i t a t i o n - paragenesis i s : s p h a l e r i t e galena — p y r i t e - — dolomite - -bari t e ( ? ) quartz Temp.: - primary f l u i d i n c l u s i o n s i n s p h a l e r i t e yielded homogenization temperatures of 243 ,9°C (10025-4) and 238.2°C (10025-6) — homogenization temperature for i n c l u s i o n s i n quartz provided a r e s u l t of 165°C; t h i s lower temperature i s l i k e l y due to the l a t e r stage of formation of the quartz Identity: 10026, Vug Geodata: - a t o t a l of eight showings are known from t h i s l o c a t i o n - the most common mi n e r a l i z a t i o n type, and the highest grades, are found i n narrow, e r r a t i c f a u l t breccia zones, trending north to northeast, and hosted i n orange—weathering H e l i k i a n dolomite - fractures j u s t outside the f a u l t b r e c c i a zone are not mineral-ized - t y p i c a l l y , the brecciated angular dolomite fragments are held In a matrix of s p h a l e r i t e , galena and white sparry dolomite - s p h a l e r i t e and dolomite appear contemporaneous and may also contain disseminated p y r i t e Polished: - angular banded p y r i t i c dolomite host rock fragments are i n f i l l e d by a s i n g l e phase of medium to f i n e , i r r e g u l a r grains of s p h a l e r i t e and sparry dolomite - the angular breccia fragments, the r e s t r i c t i o n of m i n e r a l i z a t i o n to the f a u l t zones, and the simple nature of the mineralogy, a l l point to a rapid i n f i l l i n g of the breccia and p r e c i p i t a t i o n of s p h a l e r i t e and dolomite Identity: 10027, Cominco 7 + D Geodata: - galena and s p h a l e r i t e are hosted by Hadrynian dolomite Spec. Descr, Hand: - the specimens are e s s e n t i a l l y massive, coarsely c r y s t a l l i n e s p h a l e r i t e with minor galena and p y r i t e and abundant sparry dolomite w i t h i n a breccia - t h e s p h a l e r i t e i s mottled amber to brown - the galena i s medium to coarse grained, i n i r r e g u l a r blebs and often associated with f i n e grained p y r i t e - fractures i n galena and s p h a l e r i t e are i n f i l l e d with coarse 173 white sparry dolomite and fragments of these sulphides f l o a t i n a dolomite gangue Polished: - two polished sections (10027-4 and 10027-5) were studied - they reveal angular fragments of coarsely c r y s t a l l i n e s p h a l e r i t e which contain traces of p y r i t e , and coarsely c r y s t a l l i n e galena with p y r i t e , a l l i n a sparry dolomite matrix - the s p h a l e r i t e grains are s l i g h t l y fractured and l o c a l l y i n f i l l e d with galena and p y r i t e , suggesting these minerals may have extended s l i g h t l y l a t e r i n paragenesis than the s p h a l e r i t e - the paragenesis appears to be: s p h a l e r i t e galena p y r i t e dolomite Identity: 10028, Cominco 1 GeOdata: - galena and s p h a l e r i t e are hosted by a S i l u r i a n to Devonian aged carbonate - colloform s p h a l e r i t e and minor galena and p y r i t e occur with c a l c i t e i n vugs and breccia zones i n a l g a l reefs - the veins and v e i n l e t s are traceable f o r considerable distances Spec. Descr.: Hand: — a medium grained, c r y s t a l l i n e d dolomite, mottled brown to grey i n colour, i s the host - t h i s host has been brecciated and i n f i l l e d by s p h a l e r i t e and sparry c a l c i t e - the thickest bands of s p h a l e r i t e form colloform layers with coarse c r y s t a l l i n e inner layers which become f i n e r outwards (Plate A-4) - the s p h a l e r i t e grows on coarse sparry c a l c i t e i n varying colour bdnds - paragenesis i s obscure and appears c y c l i c Temp.: - a single, f l u i d i n c l u s i o n temperature from a b a r i t e specimen (10028-3) yielded a r e s u l t of 158.8°C (Table A-l) Identity: 10029, Toporowski Geodata: - the matrix of an i n t r a c l a s t i c limestone conglomerate i n the S i l u r i a n to Devonian aged Delorme Formation has been replaced by s p h a l e r i t e and galena - the base of the showings i s a thrust f a u l t separating the Hadrynian Sheepbed Formation from the Delorme Formation Spec. Descr.: Hand: — the host i s an i n t r a c l a s t i c limestone b r e c c i a bearing rounded 174 and angular c l a s t s up to three cm, i n diameter which are fringed by s p h a l e r i t e and f i n a l l y the remaining spaces are i n f i l l e d by sparry c a l c i t e - some f i n e fractures cutting the host rock fragments are f i l l e d with s p h a l e r i t e Polished: - polished sections of brecciated (10029-5) and massive (10029-8) spha l e r i t e were studied - coarse s p h a l e r i t e coats the limestone fragments and i s i t s e l f fractured and i n f i l l e d with sparry c a l c i t e - the massive s p h a l e r i t e specimen shows coarse amber s p h a l e r i t e , with rare t i n y p y r i t e grains and a sparry c a l c i t e - the paragenesis appears to be: s p h a l e r i t e p y r i t e -c a l c i t e — Identity: Geodata: Spec. Descr, Hand: Polished: 10030, Cominco 3 - H e l i k i a n carbonates host s p h a l e r i t e and galena a single specimen consists of rounded s p h a l e r i t e blebs i n warped bands with galena and sparry c a l c i t e between the bands rusty weathering indicates possible disseminated p y r i t e s p h a l e r i t e occurs as f i n e to coarse grained c r y s t a l l i n e material with abundant i n c l u s i o n s of c a l c i t e sparry c a l c i t e i n f i l l s along s p h a l e r i t e grain boundaries and i n places appears to replace s p h a l e r i t e galena occurs as medium to coarse, d i s c r e t e grains, associated with the c a l c i t e and often p a r t i a l l y replacing the s p h a l e r i t e grain boundaries p y r i t e traces also occur with the c a l c i t e paragenesis appears to be: s p h a l e r i t e galena p y r i t e — c a l c i t e ;  I d e n t i t y : 10032, Cloe Geodata: — s p h a l e r i t e i s hosted i n brecciated black, calcareous shales of H e l i k i a n age — a lead geochemical anomaly i s present here, but no galena i s seen Spec. Descr.: Hand: a black calcareous shale i s w e l l brecciated into angular fragments and i s i n f i l l e d by contemporaneous white sparry dolomite and dark red s p h a l e r i t e 175 Polished: - section 10032-1 reveals angular black shale fragments which are surrounded i n i t i a l l y by coarse sparry dolomite and secondly by a phase of sp h a l e r i t e and dolomite i n f i l l i n g between grains and fragments - no other sulphides were observed Identity: I. 10033, Goz Geodata: - sp h a l e r i t e , with l e s s e r amounts of galena, minor p y r i t e and boulangerite, occur i n f l a t l y i n g , grey porous, dolomitized limestone underlying the Cambrian Sekwi Formation - m i n e r a l i z a t i o n i s i n hig h l y s i l i c i f i e d breccias, vugs, and fra c t u r e s and as disseminations - north trending f a u l t s may have been a c t i v e i n upgrading the the o r i g i n a l m i n e r a l i z a t i o n Spec. Descr, Hand: Polished: Temp. the host i s a banded dolomite with orange s p h a l e r i t e grains throughout i t ; the dolomite is s i l i c i f i e d , often to a great ext ent most specimens are highly s i l i c i f i e d and contain quartz c r y s t a l s the coarsest s p h a l e r i t e i s associated with the coarsest quartz galena might be present as f i n e disseminations or l o c a l l y as large grains associated with quartz c r y s t a l s the s p h a l e r i t e appears p a r t i a l l y dissolved and etched by the quartz t h i n quartz v e i n l e t s cut some s p h a l e r i t e grains s e c t i o n 10033-14 co n s i s t s of massive, yellow coarse grained s p h a l e r i t e with quartz i n f i l l i n g around the sp h a l e r i t e p y r i t e i s rare but i s found as f i n e grains associated with the quartz r a r e l y f i n e traces of galena w i l l replace quartz paragenesis appears to be: s p h a l e r i t e p y r i t e galena — quartz pseudo-secondary i n c l u s i o n s i n s p h a l e r i t e were studied from three specimens (Table A - l ) ; temperatures obtained were 150.5°C (10033-13), 171.6°C (10033-22), and 130.9°C (10033-25) Identity: Geodata: 10034, Birkeland - numerous pods of sp h a l e r i t e and galena occur i n bre c c i a zones of Hadrynian 'zebra 1 dolomites 176 Spec. Descr.; Hand: - the host consists of brown weathering, banded grey dolomites which have been brecciated - the b r e c c i a matrix i s composed of medium grained green sphaler-i t e and white sparry dolomite - galena i s also present as f i n e grains associated with the sph a l e r i t e or as massive matrix material Polished: - the sub-rounded grains of the carbonate host are fractured and p a r t i a l l y dissolved - the s p h a l e r i t e i s coarse, c r y s t a l l i n e material with trace inclusions of f i n e grained galena - white sparry dolomite f i l l s i n between the s p h a l e r i t e grains and has included many of the older carbonate host fragments - the paragenesis i s : s p h a l e r i t e galena — dolomite Identity: Geodata: Spec. Descr• Hand: Polished: 10035, Cominco 8 - galena and s p h a l e r i t e are hosted i n Cambrian carbonates highly angular fragments of grey m i c r i t i c dolomite host are supported by a matrix of white sparry dolomite, minor p y r i t e , and coarse, green, c r y s t a l l i n e s p h a l e r i t e the s p h a l e r i t e i s highly fractured and i n f i l l e d by v e i n l e t s of carbonate which contains disseminated p y r i t e s ection 10035-1 contains angular fragments of dolomite host surrounded by coarse white sparry dolomite; the dolomite bears t h i n stringers of p y r i t e medium to f i n e grained green s p h a l e r i t e includes some dolomite rhombs i n i t ; the s p h a l e r i t e i s w e l l fractured and carbonate and disseminated p y r i t e l o c a l l y i n f i l l the fractures no galena was observed the paragenesis i s : dolomite p y r i t e — — s p h a l e r i t e I d e n t i t y : 10036, Cominco 9 Geodata: — s p h a l e r i t e and galena are hosted i n H e l l k i a n dolomite - t h i s l o c a t i o n i s f i v e miles northeast of the Delores Creek copper m i n e r a l i z a t i o n area Spec. Descr.: Hand: - the host i s a highly angular, grey m i c r i t i c dolomite b r e c c i a 177 with many f i n e v e i n l e t s of sparry dolomite - s p h a l e r i t e occurs as open space f i l l i n g s , "fine s t r i n g e r s , and a one to two cm. wide v e i n l e t of coarsely c r y s t a l l i n e deep amber to red material Polished: - a polished s e c t i o n (10036-1) of the coarse vein s p h a l e r i t e reveals grey m i c r i t i c host dolomite fragments bounded by coarse c r y s t a l l i n e quartz, then narrow rims of sparry carbonate, followed by s p h a l e r i t e - the s p h a l e r i t e i s coarsely c r y s t a l l i n e , deep red and contains some fragments of the e a r l i e r carbonate phases - p y r i t e occurs as trace disseminations throughout - the paragenesis i s : quartz carbonate — sp h a l e r i t e p y r i t e — • - - -Identity: 10037, Oz GeOdata: - galena and s p h a l e r i t e are confined to r e f o l d cherty and strom-a t o l i t i c dolomites of H e l i k i a n age - the mineralized u n i t l i e s w ithin u p l i f t e d sections of Protero-zoic dolomites and p h y l l i t e s - younger Ordovician to S i l u r i a n dolomites unconformably o v e r l i e the H e l i k i a n units Spec. Descr.: Hand: - the host i s a grey, m i c r i t i c dolomite, i n part s i l i c i f i e d , and l o c a l l y brecciated i n t o angular fragments - the matrix has been i n f i l l e d by p y r i t e , galena, s p h a l e r i t e and traces of chalcopyrite - v e i n l e t s of galena and of sp h a l e r i t e , each with minor inclusions of other sulphides are present - galena also occurs as cavity f i l l i n g s and along bedding planes i n banded dolomites - p y r i t e i s commonly disseminated through the host dolomites - b r e c c i a m i n e r a l i z a t i o n might have been derived from vein and s t r a t i f o r m m i n e r a l i z a t i o n during deformation and b r e c c i a t i o n (Came, 1975) Polished: - the host rock i s macrocrystalline with laminations and contains abundant disseminated f i n e grained p y r i t e (sections 10037-31, 10037-32) - sparry c a l c i t e v e i n l e t s cutting the host contains traces of sp h a l e r i t e - a s p h a l e r i t e v e i n l e t , two cm. wide, contains sparry c a l c i t e i n c l u s i o n s and traces of p y r i t e and galena - a l a t e stage sparry c a l c i t e forms v e i n l e t s c u t t i n g a l l c o n s t i t -uents Temp: - a f l u i d i n c l u s i o n homogenization temperature of 351.0°C was obtained from a b a r i t e specimen (10037—53) from t h i s deposit (Table A-l) 178 10042, P r o f e i t - s t r a t i f o r m galena and minor s p h a l e r i t e occur i n vuggy, b r e c c i a t -ed Hadrynian dolomite, near a shale-out - m i n e r a l i z a t i o n i s found over a considerable s t r i k e length - the host i s a grey, f i n e to medium grained, porous sucrosic dolomite containing narrow sparry laminae and s p h a l e r i t e blebs - the s p h a l e r i t e , as well as galena and p y r i t e , can become f i n e l y disseminated through parts of t h i s host: where the host i s sharply brecciated the fragments are set i n a matrix of coarse white sparry dolomite and massive red to amber s p h a l e r i t e - massive, coarse sheared galena i s also found - bournonite also occurs, as sparse disseminations to large blebs i n one sample - boulangerite needles may be associated with malachite and a z u r i t e a l t e r a t i o n products - p y r i t e occurs i n v e i n l e t s , disseminations and masses of grains; t h i s can lead to extensive boxwork textures - one section each of brecciated m i n e r a l i z a t i o n (10042-8) and of copper bearing s p h a l e r i t e m i n e r a l i z a t i o n (10042-15) were studied - the brecciated material consists of massive coarse grained dark red to amber s p h a l e r i t e , massive, coarse p y r i t e , and sparry c a l c i t e - galena i s found as f i n e i n c l u s i o n s i n p y r i t e and as rare l a r g e r grains along the s p h a l e r i t e - c a l c i t e boundary - the copper bearing m i n e r a l i z a t i o n i s marked by a c i c u l a r boulan-g e r i t e i n c l u s i o n s i n bournonite; a boundary rim of malachite, azu r i t e , and c a l c i t e surrounds the bournonite - s p h a l e r i t e completely surrounds the bournonite nodule; copper carbonate a l t e r a t i o n extends i n t o the s p h a l e r i t e along c a l c i t e v e i n l e t s only short distances - the paragenesis i s complex, but appears to be: bournonite — boulangerite — s p h a l e r i t e c a l c i t e malachite/azurite — galena ? p y r i t e ? - two f l u i d i n c l u s i o n determinations yielded homogenization temperatures of 209.6°C (10042-1) and 203.7°C (10042-3) (Table A-l) 10043, Fish i n g Branch - s p h a l e r i t e occurs as^replacements and veins i n f o s s i l i f e r o u s dolomite — the host i s beneath the Gossage Formation, hence Is of probable 179 Ordovician to S i l u r i a n age Spec. Descr, Hand: the host i s a pale grey dolomite, m i l d l y brecciated and i n f i l l e d with a matrix of sparry c a l c i t e and f i n e . t o medium grained green s p h a l e r i t e the s p h a l e r i t e i s concentrated w i t h i n grey dolomite fragments i n i r r e g u l a r blebs and appears as a replacement, however i t also extends into the sparry matrix with s i m i l a r textures Polished: — s e c t i o n 10043-2 reveals the host to be m i c r o c r y s t a l l i n e dolomite containing abundant f i n e disseminated p y r i t e - s p h a l e r i t e occurs as medium to coarse grained material, intimate with sparry c a l c i t e - the c a l c i t e l o c a l l y appears to replace the s p h a l e r i t e - p y r i t e occurs as very f i n e grains, mainly associated with sparry c a l c i t e only - the paragenesis i s : s p h a l e r i t e p y r i t e c a l c i t e — Identity : 10044, Wart Geodata: - minor b r e c c i a pods and.veins of s p h a l e r i t e and galena are hosted by a c y c l i c dolomite of Ordovician to S i l u r i a n age Spec. Descr. Hand: the host i s a brown m i c r i t i c dolomite which i s cut by v e i n l e t s of dark brown coarsely c r y s t a l l i n e s p h a l e r i t e and minor galena (Plate A-4) Polished: the m i c r i t i c dolomite host i s highly p y r i t i c a t h i n i r r e g u l a r band of sparry carbonate i s concentrated along the dolomitic host-sphalerite boundary the s p h a l e r i t e i s coarsely c r y s t a l l i n e , and contains traces of disseminated p y r i t e i n s u f f i c i e n t material i s a v a i l a b l e f o r paragenetic i n t e r p r e t a -t i o n Identity: 10045, Axe Geodata: - s p h a l e r i t e and galena are hosted i n S i l u r i a n to Devonian aged carbonates Spec. Descr.: Hand: - the host i s a grey m i c r i t i c limestone containing pale green granular s p h a l e r i t e - l o c a l dark brown v a r i e t y of s p h a l e r i t e f i l l s i n between the 180 green sphalerite granules - sparry f i l l s some fractures, i n the s p h a l e r i t e Polished: - sections 10045-1 and 10045-4 reveal massive green coarsely c r y s t a l l i n e s p h a l e r i t e with l a t e r i n t e r s t i t i a l sparry c a l c i t e - green s p h a l e r i t e contains disseminated p y r i t e —paragenesis appears to be: s p h a l e r i t e red - — green p y r i t e -c a l c i t e Identity: 10046, GE 8/19/75 Geodata: - s p h a l e r i t e and galena occur i n v e i n l e t s and stringers with c a l c i t e and minor chalcopyrite and tetrahedrite i n a host of pale grey sandy calcareous dolomite of Cambrian age Spec. Descr. Hand: Polished: the host i s a porous grey dolomite with v e i n l e t s and vugs i n f i l l e d by coarse sparry c a l c i t e and medium to coarse grained red-brown s p h a l e r i t e and minor galena f i n e grained c r y s t a l l i n e s p h a l e r i t e i s dispersed, through a c a l c i t e matrix (section 10046-1) the c a l c i t e appears granular and contemporaneous with s p h a l e r i t e coarse galena c r y s t a l s p a r t i a l l y replace other minerals l o c a l l y paragenesis i s : s p h a l e r i t e c a l c i t e — • — galena Identity: 10050, Odd Geodata: - s p h a l e r i t e and galena b r e c c i a pods are hosted i n tectonic b r e c c i a zones i n a. Hadrynian 'Grit U n i t ' dolomite Spec. DesCr.: Hand: Polished: the sample i s massive, green medium grained s p h a l e r i t e with minor galena and a l a t e stage c a l c i t e f i l l i n g gaps s p h a l e r i t e occurs as coarse i r r e g u l a r grains with f i n e carbon-ate i n c l u s i o n s (section 10050-1) the s p h a l e r i t e i s w e l l fractured and sparry c a l c i t e i n f i l l s the fractures and p a r t i a l l y corrodes the s p h a l e r i t e grain boundaries the galena i s associated with the c a l c i t e between the s p h a l e r i t e grains the paragenesis i s : s p h a l e r i t e galena c a l c i t e 181 Identity: 10053, Mt. T i l l i c u m Geodata: - s p h a l e r i t e i s hosted i n Hadrynian dolomite Spec. Descr.: Hand: - the host i s a mottled brown to black dolomite cut by a vein containing c a l c i t e , p y r i t e , s p h a l e r i t e and quartz - the p y r i t e i s i n euhedral, l o c a l l y zoned, cubes and i s assoc-i a t e d with a c a l c i t e phase - c a l c i t e i s p r e c i p i t a t e d i n two to three stages - the s p h a l e r i t e i s medium to coarse grained and cut by c a l c i t e — f i l l e d f ractures Polished: - the host appears to be a bedded dolomite cut by t h i n sparry v e i n l e t s which contain traces of disseminated p y r i t e (section 10053-1) - yellow c a l c i t e has been fractured and i n f i l l e d with more sparry c a l c i t e and disseminated p y r i t e - s p h a l e r i t e forms a coarse c r y s t a l l i n e v e i n l e t which has been fractured and i n f i l l e d by a l a t e stage c a l c i t e - paragenesis i s not clear i n t h i s section and appears c y c l i c I d entity : 20003, Palm Geodata: - s p h a l e r i t e and galena are hosted i n Lower. Cambrian Sekwi Formation dolomites Spec. Descr.: Hand; - the host i s a medium grained c r y s t a l l i n e dolomite with dissem-inated s p h a l e r i t e grains throughout - traces of p y r i t e are common - vugs of c a l c i t e , s p h a l e r i t e , p y r i t e , and quartz are also present - the vugs are l i n e d with t h i n c a l c i t e l a y e r s , followed by s p h a l e r i t e with p y r i t e traces, and f i n a l l y by quartz c r y s t a l s Polished: - section 20003-5 i s dominated by coarse c r y s t a l l i n e , amber grains of s p h a l e r i t e which are highly fractured - coarse grained galena appears confined to a s i n g l e band, possibly associated with c a l c i t e ; galena replaces some sphaler-i t e grain boundaries - coarse white sparry c a l c i t e f i l l s i n between the s p h a l e r i t e grains - traces of p y r i t e are present i n the s p h a l e r i t e - the paragenesis i s : s p h a l e r i t e p y r i t e — galena c a l c i t e 182 Identity: 20004, Jude Geodata: - s p h a l e r i t e i s hosted i n the Ordovician to S i l u r i a n aged Mt. Kindle Formation dolomites Spec. Descr, Hand: Polished: angular b r e c c i a fragments of a medium grained c r y s t a l l i n e dolomite host are held i n a matrix of white sparry dolomite, s p h a l e r i t e , galena, and quartz white sparry dolomite forms euhedral c r y s t a l s and i s followed by orange, coarse grained sp h a l e r i t e , and l e s s e r amounts of galena l a t e stage euhedral quartz c r y s t a l s form druzy coatings i n some vugs i n section 20004-1 (Plate A-3) the dolomite host i s highly granular and contains abundant inclusions of p y r i t e and galena; the sulphides are dominantly found i n the i n t e r s t i c i e s between grains, but they also replace some grains the white sparry dolomite contains coarse c r y s t a l l i n e sphal-e r i t e and f i l l s i n between b r e c c i a fragments the s p h a l e r i t e may be pure or may be associated with f i n e grained galena, p y r i t e , and dolomite i n the b r e c c i a matrix the paragenesis not e a s i l y determined i n t h i s s ection Identity: 20005, Siscoe Geodata: - s p h a l e r i t e and galena, with associated f l u o r i t e , are hosted i n the Devonian aged Landry Formation limestone - emplacement i s fr a c t u r e c o n t r o l l e d Spec. Descr. Hand: Polished: a coraline grey limestone i s brecciated i n t o sub-rounded fragments and cemented with a matrix of yellow to orange, medium grained s p h a l e r i t e , white sparry c a l c i t e , and l o c a l pyrobitumen two sections (20005-1 and 20005-4) were studied the host rock, a m i c r o c r y s t a l l i n e grey limestone, contains traces of f i n e grained p y r i t e and blebs of sparry c a l c i t e coarse yellow to orange sphalerite dominates the b r e c c i a matrix f i n e grained p y r i t e and coarse sparry dolomite f i l l the i n t e r — s t i c i e s a f t e r the s p h a l e r i t e s p h a l e r i t e also occurs as coarse grained massive aggregates bearing traces of very f i n e disseminated p y r i t e sparry dolomite forms l a t e stage crosscutting v e i n l e t s paragenesis i s : s p h a l e r i t e p y r i t e dolomite 183 Identity : 20006, Pan Geodata: - disseminated galena and s p h a l e r i t e occur i n discontinuous zones within the Lower Cambrian Sekwi Formation dolomite Spec. Descr, Hand: Polished: - the host, a f i n e grained grey dolomite with o o l i t i c and a l g a l structures, i s brecciated into angular fragments and has been i n f i l l e d with white sparry dolomite, medium grained dark amber sp h a l e r i t e , and l e s s e r amounts of coarse galena and p y r i t e - sections 20006-4 and 20006-5 were studied - the m i c r i t i c , dolomite host contains abundant f i n e , euhedral p y r i t e disseminations throughout - the b r e c c i a matrix i s a complex f i l l i n g of coarse, dark amber sp h a l e r i t e bearing very f i n e grained disseminated p y r i t e , coarse euhedral galena grains, and l e s s e r amounts of p y r i t e and sparry dolomite l a t e stage, f i l l i n g i n t e r s t i c i e s sparry dolomite occurs as and fractures paragenesis appears to be: s p h a l e r i t e galena p y r i t e dolomite Identity: 20008, Backbone Geodata: - galena, s p h a l e r i t e , and smithsonite occur w i t h i n b r e c c i a zones approximately 150 to 300 metres east of a thrust f a u l t c u t t i n g the Devonian Landry Formation limestone - four showings have l o c a l very high grades Spec. Descr, Hand: the grey, m i c r i t i c limestone host i s brecciated i n t o sub-angular fragments and cemented by a matrix of sparry c a l c i t e , medium grained c r y s t a l l i n e s p h a l e r i t e , and l e s s e r amounts of medium grained galena - some vugs i n the limestone are f i l l e d by c a l c i t e and s p h a l e r i t e - oxidation i s l o c a l l y extensive, with much v i s i b l e smithsonite Polished: - the host i s a m i c r o c r y s t a l l i n e limestone with sparry i n c l u s i o n s - i n section 20008-1 the b r e c c i a matrix i s a very complex as s o c i a t i o n of coarse grained s p h a l e r i t e and galena, and f i n e to medium grained sparry c a l c i t e - a l l grains are w e l l fractured and a number of deformation periods are evident - paragenetic r e l a t i o n s are not evident i n t h i s s ection 184 20009, Weather - four showings of galena and s p h a l e r i t e are hosted i n narrow fracture b r e c c i a zones wi t h i n the Devonian aged Sombre and Arnica Formations (dolomite) near a thrust f a u l t - angular brecciated fragments of m i c r i t i c grey dolomite host rock are cemented by numerous stages of a grey calcareous mineral, white sparry c a l c i t e , s p h a l e r i t e , and galena - the s p h a l e r i t e i s medium to fine-grained, red to orange i n colour and l o c a l l y occurs as coarse c r y s t a l s i n vugs - the galena forms medium to coarse sized grains occurring as d i s c r e t e or intimately associated with s p h a l e r i t e - s e c t i o n 20009^1 consists of massive yellow orange s p h a l e r i t e , with traces of disseminated and rare galena grains - p y r i t e i s also associated with sparry c a l c i t e that f i l l s f r a c tures i n s p h a l e r i t e - the paragenesis' i s : s p h a l e r i t e galena -p y r i t e - — c a l c i t e 20012, Twitya - galena and s p h a l e r i t e , with minor quartz, c a l c i t e and tetrahe-d r i t e , occur i n brecciated, dolomitized r e e f o i d limestone i n the S i l u r i a n to Devonian aged Delorme and Devonian aged Camsell Formations - the m i n e r a l i z a t i o n f i l l s c rosscutting f r a c t u r e s , forms b r e c c i a matrices, replaces f o s s i l s , . and i s disseminated throughout - low grade s t r a t i f o r m disseminations, of s p h a l e r i t e and galena have been remobilized and upgraded i n b r e c c i a and fr a c t u r e zones adjacent to a thrust f a u l t - the host i s a grey f i n e to medium grained dolomitized limestone, brecciated and l o c a l l y h e a vily al t e r e d - sparry c a l c i t e i n f i l l s the host and i s accompanied by coarse red to amber sph a l e r i t e and l e s s e r amounts of galena - l o c a l rusty zones i n d i c a t e p y r i t e i s present - s p h a l e r i t e also occurs i n massive coarse c r y s t a l l i n e phases with f i n e traces.of galena - section 20012-11 consists of massive, deep amber to yellow-green s p h a l e r i t e , with traces of f i n e galena grains i n fracture between, and l o c a l l y p a r t i a l l y r eplacing, the s p h a l e r i t e grains - f i n e c a l c i t e f i l l s l a t e stage fractures - p y r i t e occurs as rare traces within the s p h a l e r i t e or between the s p h a l e r i t e grains 185 - the paragenesis appears to be: s p h a l e r i t e galena p y r i t e c a l c i t e Temp.: - f l u i d i n c l u s i o n homogenization temperatures on s p h a l e r i t e from th i s deposit were 308.1°C (20012-4a) and 204.0°C (20012-4b) (Table A-l) - also, a sulphur isotope analysis performed on galena-sphalerite pairs from t h i s deposit yielded a temperature of 400°C (20012-1) (Table A-2) Identity: 20013 ' Essau Geodata: s p h a l e r i t e , w i t h minor galena, f i l l ' s vugs i n a d o l o m l t i c limestone of Hadrynian age v e i n l e t s and disseminations occur l o c a l l y Spec. DesCr. Hand: Polished: a dark grey m i c r i t i c dolomitic host has been brecciated and appears to have been p a r t i a l l y dissolved i n t o rounded i r r e g u l a r fragments the matrix appears to have formed i n i t i a l l y from coarse grained, orange c r y s t a l l i n e s p h a l e r i t e i n rounded grains which was followed by white, c r y s t a l l i n e quartz i n f i l l i n g fractures through the host rock fragments and enclosing the s p h a l e r i t e grains the host i s macrocrystalline, contains traces of disseminated p y r i t e , and i s cut by fractures which also contain p y r i t e (section 20013-1) sp h a l e r i t e occurs i n the matrix as coarse c r y s t a l l i n e grains, somewhat fractured and containing c a l c i t e traces i n the fractures quartz forms the remainder of the matrix, enclosing both the s p h a l e r i t e and the host rock fragments a complete paragenesis i s not shown i n t h i s section Identity: 20015, Jim Geodata: - s p h a l e r i t e , with minor galena, occurs as v e i n l e t s i n h i g h l y fractured grey dolomite of Devonian age Spec. Descr, Hand: - l i t t l e of the host dolomite i s present i n specimens a v a i l a b l e - specimens consist mainly of s p h a l e r i t e i n two forms; f i n e grained green s p h a l e r i t e i s dominant and i s cut by fractures containing coarser orange s p h a l e r i t e , sparry c a l c i t e , and 186 minor galena - one specimen consists of massive orange s p h a l e r i t e which i s w e l l fractured and i n f i l l e d with sparry and some galena Polished: - s e c t i o n 20015-1 consists of massive coarse grained s p h a l e r i t e with abundant carbonate inclusions throughout - fractures through the s p h a l e r i t e are f i l l e d with carbonate as w e l l - galena occurs as i r r e g u l a r disseminations - paragenesis i s : galena s p h a l e r i t e p y r i t e — c a l c i t e Identity: 20019, Gildersleeve Geodata: - s p h a l e r i t e , with minor galena, occurs i n three separate s t r a t i f o r m mineralized horizons i n the Lower Cambrian Sekwi Formation i n dolomite slump breccias Spec. Descr. Hand: Polished: the host i s a f i n e grained c r y s t a l l i n e dolomite, l o c a l l y banded with s o f t sediment deformation features f i n e grained green sphalerite.occurs throughout most of the host, and a medium grained green to amber s p h a l e r i t e occurs i n scattered blebs l o c a l l y , b r e c c i a i n f i l l i n g s of greenish s p h a l e r i t e are followed by coarse white sparry c a l c i t e the host i s a m i c r i t i c dolomite with abundant disseminated p y r i t e (section 20019-1), brecciated i n t o angular fragments c a l c i t e or sphalerite.may occur around the host rock fragments s p h a l e r i t e occurs as coarsely c r y s t a l l i n e , r e l a t i v e l y pure grains; f i n e fractures i n the s p h a l e r i t e are f i l l e d with c a l c i t e p y r i t e occurs as disseminations, mainly i n sparry c a l c i t e areas, but l o c a l l y i s found within c a l c i t e f i l l e d fractures through the sphalerite sparry c a l c i t e i s the f i n a l stage paragenesis i s : s p h a l e r i t e p y r i t e c a l c i t e I d e n t i t y : GeOdata: 20020, Mogul - s p h a l e r i t e , with minor galena, occurs i n b r e c c i a zones i n ar g i l l a c e o u s dolomites of the Sekwi Formation of Lower Cambrian age 187 - possibly r e l a t e d to a nearby thrust f a u l t Spec. Descr.: Hand: - the host i s a f i n e grained grey dolomite, l o c a l l y brecciated - f i n e grained green s p h a l e r i t e occurs throughout or as coarse greenish-brown grains i n the b r e c c i a matrix - p y r i t e i s also common as f i n e disseminations associated with the s p h a l e r i t e - sparry c a l c i t e occurs as a l a t e stage Polished: - section 20020-3 reveals that t h e m a c r o c r y s t a l l i n e dolomite host contains abundant f i n e disseminated p y r i t e - s p h a l e r i t e occurs as coarse c r y s t a l l i n e grains with in c l u s i o n s of carbonate within grains and i n fractures through the s p h a l e r i t e - p y r i t e i s commonly found with the carbonate and l o c a l l y i n the fractures i n sphalerite - the carbonate cement i s very granular and may be s l i g h t l y r e - c r y s t a l l i z e d - paragenetic r e l a t i o n s are obscure In t h i s section Identity : 20021, F.C. Claims Geodata: - massive s p h a l e r i t e , with b a r i t e and minor galena, f i l l a s o l u t i o n b r e c c i a i n the Devonian Camsell Formation limestone a m i c r i t i c grey dolomite host i s brecciated into angular fragments and cemented by narrow i n f i l l i n g s of medium to coarse grained amber sp h a l e r i t e followed by white sparry dolomite Polished: - section 20021-1 (Plate A-3) reveals the macrocrystalline dolomite host bears disseminated p y r i t e throughout; l o c a l l y p y r i t e forms medium grained dense aggregates - angular b r e c c i a fragments of the host rock are rimmed by a narrow sparry carbonate layer - the dominant matrix material i s a coarse c r y s t a l l i n e s p h a l e r i t e which contains traces of p y r i t e and carbonate as in c l u s i o n s and as fracture f i l l i n g s - sparry c a l c i t e forms the e a r l i e s t and l a t e s t phases i n matrix i n f i l l i n g s - the paragenesis i s : s p h a l e r i t e p y r i t e — c a l c i t e Spec. Descr.: Hand: 188 Identity: 20023, Rev Geodata: - sp h a l e r i t e and galena occurs i n veins and as disseminations at four showings associated with f a u l t s i n the Ordovician to S i l u r i a n aged Mt. Kindle Formation dolomites Spec. Descr. Hand: Polished: Temp.: a f o s s i l i f e r o u s dolomite host, with l o c a l arenaceous layers, contains veins and solu t i o n c a v i t i e s i n f i l l e d with massive coarse c r y s t a l l i n e s p h a l e r i t e , galena, and sparry dolomite (Plate A-l) the s p h a l e r i t e may be massive orange, green, or colo u r l e s s and i s intimate with coarse galena where t h i s i s present sparry dolomite f i l l s vugs as a l a t e stage much smithsonite i s l o c a l l y present l o c a l l y quartz c r y s t a l s occur as a f i n a l stage two sections were studied (20023-126, 20023-127, 128) the sections contain massive, coarsely c r y s t a l l i n e s p h a l e r i t e with trace Inclusions of f i n e p y r i t e and some sparry c a l c i t e s e ction 127,128 contains two d i s t i n c t colours of s p h a l e r i t e intimately intergrown i n one hand specimen (127 i s br i g h t orange, 128 i s colourless to pale green); t h i s d i s t i n c t i o n i s only v i s i b l e under crossed n i c o l s complete paragenesis i s not seen i n these sections f l u i d i n c l u s i o n homogenization temperatures provided r e s u l t s of 187.3°C on sp h a l e r i t e (20023-67) and of 210.7°C on quartz (20023-99a) (Table A - l ) ; note that these specimens are from d i f f e r e n t showings on t h i s property sulphur isotope analysis of galena-sphalerite p a i r s y i e l d e d temperatures of 220°C (20023-14) arid 215°C (20023-24) f o r the Main showing, 325°C (20023-98) f o r the Wat e r f a l l showing, and 670°C (20023-146) f or the West Cirque showing (Table A-2) Identity: 20024, Gayna River Geodata: - numerous s p h a l e r i t e and galena showings are hosted i n b r e c c i a t -ed Hadrynian dolomites - most of the mine r a l i z a t i o n i s near to a limestone-dolomite in t e r f a c e i n collapse breccias along a s i n g l e horizon - the m i n e r a l i z a t i o n i s also near to a shale-carbonate f a c i e s change - the showings include m i n e r a l i z a t i o n i n 1) fragmental slump and talus breccias, 2) s t o m a t o l i t i c r e e f o i d flanks, and 3) f i s s u r e veins - extensive gypsum i s present i n the area Spec. Descr.: Hand: the h o s t - i s a f i n e grained grey m i c r i t i c dolomite, well brecciated into angular fragments, and cut by carbonate and sulphide v e i n l e t s 189 - the bre c c i a matrix consists of white sparry c a l c i t e followed by coarse grained c r y s t a l l i n e s p h a l e r i t e of amber to orange colour, coarse grained galena, and much p y r i t e - l o c a l l y some massive pieces of c r y s t a l l i n e s p h a l e r i t e bears i n t e r s t i t i a l p y r i t e and l a t e stage c a l c i t e - some vugs are f i l l e d with c a l c i t e and c r y s t a l l i n e purple f l u o r i t e Polished; - the sections studied (20024-5 and 20024-8) do not contain any host rock material - section 20024-5 contains abundant euhedral p y r i t e and c a l c i t e grains set i n coarse grained s p h a l e r i t e - p y r i t e and c a l c i t e are also often w e l l rounded and are found along s p h a l e r i t e grain boundaries as w e l l as throughout the sph a l e r i t e i t s e l f - the sp h a l e r i t e i n t h i s section appears to be a l a t e stage, enclosing a l l previous phases - s e c t i o n 20024-8 contains coarse,: granular s p h a l e r i t e which again bears euhedral p y r i t e and c a l c i t e , but only i n trace quantities - otherwise carbonate forms the matrix surrounding the s p h a l e r i t e and some quartz grains - the o v e r a l l paragenesis appears to be: sp h a l e r i t e p y r i t e c a l c i t e — quartz Identity: 20025, Tegart GeOdata: - galena and s p h a l e r i t e occur i n various mineralized horizons over a thickness of 150 m. i n the upper Sekwi Formation (Lower Cambrian) and the Mt. Kindle Formation (Ordovician to S i l u r i a n ) dolomites - m i n e r a l i z a t i o n appears to be frac t u r e c o n t r o l l e d near a f a u l t zone Spec. Descr.: Hand: - a medium to f i n e grained c r y s t a l l i n e grey dolomite with aren-aceous and vuggy parts, comprises the host (Plate A-5) - the vugs and fractures are i n f i l l e d with coarse c r y s t a l l i n e c a l c i t e followed by coarse, green s p h a l e r i t e , l o c a l l y with p y r i t e , and often a f i n a l stage of euhedral quartz c r y s t a l s - some specimens are massive pure c r y s t a l l i n e s p h a l e r i t e - some brecciated specimens show p y r i t e rimming the dolomite host fragments, which i s then followed by sparry c a l c i t e and coarse c r y s t a l s of s p h a l e r i t e and galena Polished: - two sections (20025-1 and 20025-11) reveal a f i n e to medium grained p y r i t i e host dolomite has been mi l d l y fractured and i n f i l l e d by coarse sparry c a l c i t e and medium to coarse grained c r y s t a l l i n e s p h a l e r i t e 190 - the s p h a l e r i t e l o c a l l y includes euhedral c a l c i t e rhombs - the complete paragenesis i s obscure i n these sections Identity: 20027, Climax Geodata: Spec. Descr, Hand: Polished: Temp.: sp h a l e r i t e and minor galena, with euhedral quartz c r y s t a l s bearing jamesonite needles, i s hosted i n a Hadrynian dolomite - the specimens present consist of coarse grained h i g h l y fractured and somewhat oxidized s p h a l e r i t e with minor amounts of galena, boulangerite, and abundant euhedral quartz'crystals which contain f i n e black jamesonite i n t e r n a l l y - the specimens a v a i l a b l e were not s u i t a b l e f o r polished sections - paragenetic descriptions are taken from Penco (1976) - paragenesis appears to be re l a t e d to two hydrothermal stages: 1) a phase of production of milky quartz and ferroan dolomite as open space f i l l i n g s , followed by colourless euhedral quartz c r y s t a l s containing needles of galena and boulangerite 2) a phase of p r e c i p i t a t i o n of s p h a l e r i t e , t e t r a h e d r i t e , boulangerite, galena, and minor p y r i t e completely or p a r t i a l l y f i l l e d the remaining voids - f l u i d i n c l u s i o n homogenization temperatures on s p h a l e r i t e produced r e s u l t s of 246.4°C (20027-1) to 278.0°C (20027-3); f l u i d i n c l u s i o n s i n quartz yielded s i m i l a r temperatures of 270°C (Table A-l) Identity: 20032, Mountain River Geodata: — s p h a l e r i t e and galena occur i n q u a r t z - c a l c i t e veins and breccia zones in. the S i l u r i a n to Devonian aged Delorme Formation dolo-mites Spec. Descr, Hand: Polished: the fractured, medium to f i n e grained, grey dolomite host rock contains t h i n c a l c i t e v e i n l e t s , which i n t h i s specimen, bear medium grained c r y s t a l l i n e s p h a l e r i t e of dark amber colour the s p h a l e r i t e l o c a l l y contains inclusions of f i n e galena section 20032-1 reveals the host dolomite i s macrocrystalline and contains rare traces of disseminated p y r i t e also t h i n v e i n l e t s of sparry c a l c i t e and disseminated s p h a l e r i t e cut through the host fragments 191 - s p h a l e r i t e occurs as massive coarsely c r y s t a l l i n e material which i s w e l l fractured and cut by t h i n v e i n l e t s of sparry carbonate - much of the sph a l e r i t e i s free of i n c l u s i o n s , however near the contact with the host dolomite i r r e g u l a r grains of galena and sparry carbonate occur; these grains appear i n part to be replacing the sph a l e r i t e - the paragenesis appears to be: s p h a l e r i t e galena carbonate Identity: 20034, Kind Geodata: - s p h a l e r i t e and galena are hosted i n the Ordovician to S i l u r i a n aged Mt. Kindle Formation dolomites Spec. Descr, Hand: a brecciated, grey arenaceous dolomite with abundant c a l c i t e s t r i n g e r s i s cemented by a matrix of coarse sparry white c a l c i t e followed by green to red coarse c r y s t a l l i n e s p h a l e r i t e and quartz c r y s t a l s Polished: - section 20034-1 reveals that the host rock fragments are of a medium grained c r y s t a l l i n e dolomite - sparry c a l c i t e i s found adjacent to the host rock fragments - s p h a l e r i t e i s found as f i n e inclusions at the outer edge of thi s c a l c i t e zone and i t becomes massive and p a r t i a l l y replaces the c a l c i t e - the sph a l e r i t e i s fractured and i n f i l l e d x<rith t h i n v e i n l e t s of c a l c i t e - galena i n c l u s i o n s within deformed twin planes of the s p h a l e r i t e are common, p a r t i c u l a r l y close to the sparry c a l c i t e and the host dolomite - the paragenesis i s : c a l c i t e s p h a l e r i t e galena Identity: 20035, Serem Geodata: - sp h a l e r i t e and galena occur i n the Ordovician to S i l u r i a n aged Mt. Kindle Formation dolomites, near to a shale-out Spec. Descr.: Hand: - the host rock i s a f i n e grained grey dolomite brecciated i n t o angular fragments and cemented i n a matrix of white sparry c a l c i t e - red to green s p h a l e r i t e f i l l s vugs i n the c a l c i t e 192 - l o c a l l y some sp h a l e r i t e grains are enclosed by a l a t e r c a l c i t e - euhedral quartz c r y s t a l s l o c a l l y f i l l some vugs as a l a s t stage Polished: — the host dolomite i s f i n e l y c r y s t a l l i n e and c a r r i e s disseminated p y r i t e (sections 20035-2 and 20035-5) - c a l c i t e i s t h e - I n i t i a l phase surrounding the host fragments - the s p h a l e r i t e , following the i n i t i a l c a l c i t e , tends to be massive, coarsely c r y s t a l l i n e , and contains f i n e fractures which are c a l c i t e f i l l e d - f i n e disseminated grains of p y r i t e and galena are present - quartz c r y s t a l s , subhedral, are present with the c a l c i t e matrix and i n the s p h a l e r i t e - the paragenesis appears to be: sphalerite c a l c i t e p y r i t e galena quartz Identity: 20036,Kwi Geodata: - s p h a l e r i t e occurs i n the Lower Cambrian Sekwi Formation dolomites Spec. Descr.: Hand: - a f i n e grained, black dolomite has been brecciated into coarse and f i n e angular fragments which are cemented i n a matrix of sparry white c a l c i t e and green s p h a l e r i t e (Plate A-l) - the s p h a l e r i t e i s medium to coarse grained, l o c a l l y corrodes the host dolomite, and i s i n part enclosed by c a l c i t e - the c a l c i t e appears as a l a s t stage, cementing the matrix f u l l y Polished: - the f i n e l y c r y s t a l l i n e dolomite host bears disseminated p y r i t e throughout (section 20036-1) - the s p h a l e r i t e i s c o a r s e l y . c r y s t a l l i n e and r e l a t i v e l y free of i n c l u s i o n s , however i n t e r n a l fractures are c a l c i t e f i l l e d - the sparry c a l c i t e appears to be contemporaneous with s p h a l e r i t e as evidenced by regular contacts and i n c l u s i o n s of one with the other - l a t e stage euhedral quartz c r y s t a l s . a r e present around both the c a l c i t e and the s p h a l e r i t e - the paragenesis i s : s p h a l e r i t e — • c a l c i t e quartz 193 Identity: 20037, GJ 7/30/75 Geodata: - s p h a l e r i t e occurs i n a strongly brecciated and fractured f i n e grained Devonian dolomite within a f a u l t zone Spec. Descr.: Hand: — a m i c r i t i c dark grey dolomite has been brecciated and w e l l fractured and i n f i l l e d mainly by orange s p h a l e r i t e i n t h i n v e i n l e t s and open space f i l l i n g s (Plate A-2) - sparry c a l c i t e forms rare, v e i n l e t s which are cut o f f by the s p h a l e r i t e Polished: - s e c t i o n 20037-1 reveals that the macrocrystalline dolomite host contains disseminated p y r i t e throughout - the host rock i s highly fragmented and i n f i l l e d by r e l a t i v e l y pure medium grained c r y s t a l l i n e s p h a l e r i t e - the s p h a l e r i t e has been fractured and cut by numerous sparry c a l c i t e v e i n l e t s which l o c a l l y carry s p h a l e r i t e grains i n t o v e i n l e t s through the host fragments - the paragenesis i s : s p h a l e r i t e c a l c i t e Identity: 20038, GJ 7/14/75 Geodata: - s p h a l e r i t e i s hosted i n an Ordovician to S i l u r i a n aged dolomite 1.5 km, from the Kind deposit (20034) Spec. Descr, Hand: Polished: a medium grained, c r y s t a l l i n e , grey dolomite has been b r e c c i a t -ed and contains v e i n l e t s , s o l u t i o n c a v i t y f i l l i n g s , and matrix f i l l i n g s of coarse s p h a l e r i t e and sparry dolomite section 20038—1 reveals that the medium grained dolomite host bears disseminated p y r i t e and i s often p a r t i a l l y dissolved and cemented by sparry dolomite sharp contacts are seen between the s p h a l e r i t e grains and the sparry dolomite some incl u s i o n s of dolomite i n s p h a l e r i t e occur, but the coarsest s p h a l e r i t e tends to be free of i n c l u s i o n s other than the dolomite f i l l e d fractures the paragenesis i s : s p h a l e r i t e c a l c i t e I d entity: Geodata: 20039, Gun - s p h a l e r i t e , with minor galena and b a r i t e , i s hosted i n Cambrian limestone 194 Spec. Descr, Hand: Polished: a f i n e to medium grained granular limestone i s fragmented and replaced by medium grained granular s p h a l e r i t e the e n t i r e specimen appears r e - c r y s t a l l i z e d i n t o granules the specimen i s dominantly rounded, grains of s p h a l e r i t e set i n a matrix of sparry c a l c i t e , and minor amounts of granular carbonate host the boundary r e l a t i o n s tend to indicate c o - p r e c i p i t a t i o n of the s p h a l e r i t e and c a l c i t e followed by l a t e r r e - c r y s t a l l i z a t i o n traces of disseminated p y r i t e are present w i t h i n both the sp h a l e r i t e and the c a l c i t e the paragenesis i s : s p h a l e r i t e • p y r i t e c a l c i t e I d entity : 20040, GJ 7/27/75 Geodata: - sphalerite occurs i n the Ordovician to S i l u r i a n Mt. Kindle Formation dolomite Spec. Descr.: Hand: - pale grey, subrounded, m i c r i t i c dolomite b r e c c i a fragments are cemented by coarse white'sparry dolomite and coarse green to orange s p h a l e r i t e blebs d i s t r i b u t e d throughout Polished: - the medium grained c r y s t a l l i n e dolomite host fragments are somewhat corroded and replaced by sparry c a l c i t e and s p h a l e r i t e (section 20040-1) - commonly, sparry c a l c i t e forms narrow bands between s p h a l e r i t e and the host rock fragments - some f i n e s p h a l e r i t e grains are included i n sparry material - the paragenesis i s : c a l c i t e — - — — s p h a l e r i t e 1 T A B L E A - l F L U I D I N C L U S I O N AND L A S T M E L T I N G H O M O G E N I Z A T I O N D A T A F O R I N C L U S I O N S I N M I N E R A L S A S S O C I A T E D W I T H C A R B O N A T E H O S T E D Z I N C - L E A D D E P O S I T S , Y . T . A N D N . W . T . ( a f t e r G o d w i n , 1 9 7 7 ) N U M B E R S A M P L E M I N . A a n d T Y P E 5 D E P O S I T 6 . L A S T M E L T I N G ° C 7 • • H O M O G E N I Z A T I O N ° C 7 LOW M E A N H I G H NO LOW M E A N H I G H NO 1 0 0 0 6 0 0 3 S L PS D NEWT - 2 8 . 0 - 2 3 . 2 - 1 8 . 0 4 1 2 0 . 0 1 2 5 . 9 1 3 3 . 0 1 0 1 0 0 0 6 0 0 5 S L PS O R S NEWT - 1 3 . 5 - 1 2 . 1 - 9 . 4 6 1 2 4 . 0 1 3 1 . 5 1 3 4 . 9 4 1 0 0 1 0 0 0 1 S L P O R PS E C O N O M I C - 5 . 5 - 4 . 6 - 4 . 1 3 1 4 3 . 3 1 5 2 . 0 1 6 0 . 7 2 1 0 0 2 5 0 0 4 S L P a n d P S C O M I N C O B C - 6 . 1 - 5 . 5 - 4 . 9 2 2 4 0 . 0 2 4 3 . 9 2 5 0 . 8 4 1 0 0 2 5 0 0 4 Q Z P S C O M I N C O B C - 3 . 4 - 3 . 4 - 3 . 4 4 1 6 3 . 2 1 6 5 . 0 • 1 6 7 . 5 7 1 0 0 2 5 0 0 4 Q Z S C O M I N C O B C — - 1 . 4 — 1 L O W E R T H A N F O R P S 1 1 0 0 2 5 0 0 6 • S L P a n d P S C O M I N C O B C - 4 . 9 - 4 . 5 - 4 . 0 2 2 3 0 . 0 2 3 8 . 2 2 5 0 . 8 5 1 0 0 2 8 0 0 3 B A P C O M I N C O 1 - 3 . 9 - 3 . 6 - 3 . 2 2 — 1 5 8 . 8 — 1 1 0 0 3 3 0 1 3 S L PS GOZ - 6 . 8 - 4 . 4 - 4 . . 5 ' 8 . 1 4 6 . 0 1 5 0 . 5 1 5 5 . 0 4 1 0 0 3 3 0 2 2 S L P S G O Z - 1 2 . 3 - 1 1 . 1 - 9 . 5 4 1 6 9 . 9 1 7 1 . 6 ' 1 7 3 . 3 2 1 0 0 3 3 0 2 5 S L P S G O Z - 1 5 . 8 - 1 5 . 7 - 1 5 . 6 2 — 1 3 0 . 9 — 1 1 0 0 3 7 2 0 5 3 B A P OZ N O T D O N E 0 3 4 5 . 0 3 5 1 . 0 3 5 3 . 0 4 1 0 0 4 2 0 0 1 S L P S P R O F E I T - 8 . 6 - 7 . 3 - 6 . 6 3 2 0 1 . 8 2 0 9 . 6 2 1 7 . 2 • 3 1 0 0 4 2 0 0 3 S L P P R O F E I T - 9 . 3 - 9 . 3 - 9 . 3 3 1 9 5 . 0 2 0 3 . 7 2 1 2 . 4 2 2 0 0 1 2 0 0 4 A ' S L P O R P S T W I T Y A - 2 . 8 - 2 . 4 - 2 . 1 2 3 0 7 . 2 3 0 8 . 1 3 0 9 . 0 2 2 0 0 1 2 0 0 4 B S L P O R P S T W I T Y A - 1 . 4 - 1 . 3 - 1 . 3 2 — 2 0 4 . 0 ? — 1 2 0 0 2 3 0 2 5 Q Z P S R E V ( M A I N ) - 7 . 0 - 5 . 0 - 3 . 0 4 I N C L U S I O N S L E A K E D 0 2 0 0 2 3 0 6 7 3 S L P o r P S R E V ( E S A U ) - 1 5 . 7 - 1 5 . 4 - 1 5 . 1 2 1 8 0 . 0 1 8 7 . 3 1 9 0 . 0 9 2 0 0 2 3 0 9 9 A 3 Q Z P S D R E V ( W A T F ) N O T DONE 0 1 6 5 . 0 2 1 0 . 7 2 4 6 . 0 5 2 0 0 2 7 0 0 1 S L P C L I M A X - 8 . 7 - 8 . 1 - 7 . 5 4 2 0 0 . 5 2 4 6 . 3 2 7 9 . 0 4 2 0 0 2 7 0 0 2 S L P S D C L I M A X - 9 . 0 - 8 . 3 - 7 . 6 2 2 6 5 . 5 2 6 7 .9 2 7 2 . 0 4 2 0 0 2 7 0 0 3 S L P C L I M A X - 8 . 0 - 6 . 9 - 6 . 2 3 — 2 7 8 . 0 — 1 ^ A l l r u n s w e r e b y J . M c L e o d , u n l e s s n o t e d . R u n s w e r e b y R . C a r n e . R u n s w e r e b y M . M c A r t h u r . 5 M i n e r a l h o s t t o f l u i d i n c l u s i o n i s c o d e d a s f o l l o w s : S L = s p h a l e r i t e , Q Z = q u a r t z , F U = f l u o r i t e , B A = . ; b a r i t e , C A = . r . c a l c i t e . . g T y p e o f f l u i d i n c l u s i o n i s c o d e d a s f o l l o w s : P = p r i m a r y , P S = p s e u d o - s e c o n d a r y , S = s e c o n d a r y , D = d a u g h t e r p r o d u c t n o t e d . ^ D e p o s i t c h a r a c t e r , l o c a t i o n , e t c . a s i n ' f h i e - p r e c e d i n g d e s c r i p t i o n s . . T e m p e r a t u r e d a t a a r e u n c o r r e c t e d f o r p r e s s u r e o r i n s t r u m e n t d e v i a t i o n ; c a l i b r a t i o n c h a r t f o r i n s t r u m e n t i s i n ' F i g u r e A - l . Figure A - i : Calibration curve (April 1976) defining deviation in temperature between consol read out and stage temperature. Chaixmeca f l u i d inclusion heating and freezing stage, room 301, Department of Geological Sciences, U.B.C. TABLE A-2 SULPHUR ISOTOPE ANALYSIS OF GALENA-SPHALERITE PAIRS FROM CARBONATE HOSTED ZINC-LEAD DEPOSITS, N.W.T. (afte r Godwin, 1977) 8S34 0/00 AS 3 4S 0/00 APPX. NUMBER 20012-1 20023-14 20023-24 20023-98 20023-146 NAME TWITYA (BEAR) REV (MAIN SHOW) REV (MAIN SHOW) REV (WATERFALL) REV (WEST CIRQUE) N.T.S. LAT, LONG. GALENA SPHALERITE SPHALERITE-GALENA TEMP. 106/A/03 64.03 129.37 +10.382 +12.192 106/A/03 64.13 129.33 +6.03 +9.43 106/A/03 64.13 129.33 +6.53 +10.03 106/A/03 64,13 129.33 +10.93 +13.I 3' 4 106/A/03 64.13 129.33 11.4 3' 5 12.35 3' 6 1.81 3.4 3.5 2.2 0.95 400 220 215 325 670 2 Analyses by Dr. C.E. Rees, Department of Physics, McMaster University, Hamilton, Ontario, L8S 4K1. ^ Mass spectrometry on samples converted to SF6. ^ Mass spectrometry on samples converted to SO2. ^ Two separate analyses both +13.1. g Two separate analyses both +11.4. -j Two separate analyses, one +12.3, the other +12.4. Temperature determined from graph by Kajiwara and Krouse, 1971 ( F i g . 1). 198 a) Fragments of dolomite host rock (dark grey) are h e l d i n a matrix of sparry dolomite (white) and orange and green coarse s p h a l e r i t e ( g r e y ) . (specimen 20023-141) b) A dolomite host (dark grey) i s b r e c c i a t e d i n t o angular fragments and i n f i l l e d by sparry c a l c i t e (white) and green s p h a l e r i t e (grey) . Late c a l c i t e f i l l e d f r a c t u r e s cut a l l fragments. (specimen 20036-1) PLATE A - l : BRECCIA TEXTURES 199 a) Fragments of host dolomite (dark grey) are enclosed by a s p h a l e r i t e rim (grey) . P y r i t e forms a band extending through the specimen and c a l c i t e (white) f i l l s i n remaining spaces. Late fractures cut a l l other phases, (specimen 20036-1) b) The host dolomite (dark grey) has been brecciated and i n f i l l e d by orange s p h a l e r i t e (grey) and c a l c i t e (white). Continued f r a c t u r i n g produced sparry c a l c i t e v e i n l e t s throughout the specimen, (specimen 20037-1) PLATE A-2: BRECCIA TEXTURES 200 a) The limestone host (dark grey) containing p y r i t e grains (bright white) has been brecciated into angular fragments and i n f i l l e d by coarse, r e l a t i v e l y pure sphalerite (pale grey). (specimen 20021-1; magnification X75) b) Porous granular host dolomite (grey, at l e f t ) has been fragmented and i n f i l l e d by sparry dolomite (dark grey rhomb) and coarse s p h a l e r i t e (pale grey, centre); traces of galena are also present. (specimen 20004-1; magnification X75) PLATE A-3: BRECCIA TEXTURES 201 a) Brown dolomite (grey) with abundant fine p y r i t e i s cut by a dark brown coarse s p h a l e r i t e v e i n l e t (dark grey) . (specimen 10044-1) b) Successive bands of brown-green (dark grey i n photo) and yellow (pale grey i n photo) sphalerite form colloform layers over sparry c a l c i t e (white) . C a l c i t e also occurs at l a t e r stages with s p h a l e r i t e . Traces of galena are present (black speck, lower right) . (specimen 10028-5) PLATE A-4: VEIN TEXTURES 202 a) Grey dolomite host (pale grey i n photo) i s arenaceous and vuggy. Vugs are i n f i l l e d by sparry c a l c i t e (white) and dark brown s p h a l e r i t e (dark grey) . (specimen 20025-1) PLATE A-5: VUG AND CAVITY FILLING TEXTURE 203 APPENDIX B REGIONAL GEOLOGIC MAP AND CORRELATION CHART 204 APPENDIX B) REGIONAL GEOLOGIC MAP AND CORRELATION CHART The r e g i o n a l geologic map (Figure 4-2) i n t h i s t h e s i s was compiled from a number of sourcer.maps (Table B-l) , a l l of which are a v a i l a b l e from the G e o l o g i c a l Survey of Canada. A c o r r e l a t i o n chart of map u n i t s from each of the sources used i s provided i n Table B-2 s i n c e a l l u n i t s are not c o n s i s t e n t l y named on each source map. The legend of the c o m p i l a t i o n map i s broken down i n t o r e g i o n a l u n i t s considered most c r i t i c a l to t h i s study f o r r e g i o n a l metallogeny and i s based on age and l i t h o l o g y . TABLE B - l SOURCES USED IN COMPILATION OF THE REGIONAL MAP NTS Reference Source Author Approximate Scale 105 I 105 P 105 0,N 106 A,B (northern parts) 106 A,B,C Map 18-1967 Green et a l . , 1967 l"=4miles Blusson, 1971 GSC Paper 7.1.-22 GSC.Open F i l e Blusson, 1974 205 GSC Open F i l e Blusson, 1974 221 GSC Open F i l e Blusson, 1974 205 l"=4miles l"=4miles l"=4miles l"=4miles l"=4miles 106 D, 116 A,B,C GSC Memoir 364 Green, 1972 106 E,F,K,L, 116 GSC Map 10- N o r r i s et a l . , 1963 l"=16miles F,G,H,I,J,K, 1963 TABLE B-2 REGIONAL CORRELATION CHART Units Used i n This Report Age Formations or _ _ _ _ _ _ _ _ _ _ _ _ _ L i t h o l o g i e s Recent and P l e i s t o c e n e g l a c i a l t i l l s , l a n d s l i d e s , a l l u v i u m . Green, 1972 106 D 116 A.B.C 26 g l a c i a l t i l l a l l u v i u m Blusson, 1974 106 A,B,C Blusson, 1971 105 P 32 g l a c i a l t i l l a l l u v i u m Green et a l . , 105 I 1967 N o r r i s - e t a l . , 1963 north of '65 10b Ccnozoic and i n t r u s i v e s (mainly Cretaceous stocks) sedimentary cover Gone metamorphic ro c k s , dykes, s i l l s , e t c . carbonates and e l a s t i c s 21 i n t r u s i v e s 16 - 25 s h a l e s , limestones, s h i e t s q u a r t z i t e , some gabbro. Tv v o l c a n i c s Kg i n t r u s i v e s Kd i n t r u s i v e s Trq q u a r t z i t e and shale 31 i n t r u s i v e s 15 Tahkandit Fm. Cp dolomite and 14 limestone, shale shale and sanda cone 10 - 13 s h a l e s , sand-stones, limestones. 9 limestone, s h a l e , sandstone, conglomerate 8b M l s s i s s i p p l a n to Devonian 8a M l s s i s s i p p l a n to O r d o v i c i a n 7 Devonian 6 S i l u r i a n to Devonian 5 Ordovician to S i l u r i a n 6 Upper Cambrian to O r d o v i c i a n 3 Lower Cambrian 2 Hadrynian 1 H e l i k i a n Besa R i v e r Fm. 'Black C l a s t i c ' u n i t Nahanni Fm. Headless Fm. Landry Fm. A r n i c a Fm. Sombre Fm. Cams e l l Fin. Delorme Fm. Road R i v e r Fm.(and enrbonnto f n c i e a e q u i v a l e n t ) Whlttaker Fm. Mt. K i n d l e Fa. F r a n k l i n Mountain Fm. Sunblood Fm. some v o l c a n i c s 13a Nation R i v e r Fm.DMss q u a r t z i t e 26 - 28 shale 13 s h a l e , a r g i l l i t e . D M c g l c< nglomerate and q u a r t z i t e limestone, conglom- DM s h a l e , conglom-erate erate DMs Besa River Fm. Ps s h a l e , a r g i l l i t e conglomerate 10 - 11 limestone and dolomite Sekwi Fm. Backbone Fm. Sheepbed Fm. Keele Em. Rapitan Group ( G r i t U n i t ) L i t t l e Dal Fm. GSC Unit H5 Katherine Fm. Tsetzoene Fm. CSC U n i t HI 12 limestone 9 Road R i v e r Fm. 8 dolomite, lime-stone, soma volcan-i c s Dn Nahsnni Fm. Dh Headless Fm. DI Landry Fm. Da A r n i c a Fn. Ds Sombre Fm. • Dc Camsell Fm. SI>c dolomite, limestone SDd Delorme Fm. OSDr Road River Fm. OSk Mt. Kindle Fm. 7 limestone, conglomerate 6 limestone, dolo-mite, s h a l e 5 sandstone, cong-lomerate 4 calcareous v o l c -a n i c s 3 Rapitan Group 1 - 2 dolomite, s h a l e . 25 Nahanni Fm. 24 Headless Fm. 23 Landry Fm. 22 A r n i c a Fm. 21 Sombre Fm. 20 Delorme Fm. 19 Whittaker Fm. Ov v o l c a n i c s Co dolomite, limestone Cs Sekwi Fm. Cqc Backbone Fm. HCs Sheepbed Fm. Hk Keele Fm. Hr Rapitan Group Hs G r i t Unit He } He } 18 s h a l e , sandstone conglomerate 17 Nahanni Fn. 7 - 8 s h a l e , sandstone, 16 Headless Fm. conglomerate, limestone. 15 limestone ( A r n i c a and Landry equiva-l e n t s ) 14 Landry Fm. 13 A r n i c a Fm. 12 Sombre Fm. O Ul 11 Delorme Fm. 6 Road R i v e r Fm. 5 carbonates 18 Sunblood Fm. 9 Sunblood Fm. 17 dolomite, lime- 7 limestone, dolo-stone mite, s i l t s t o n e 16 shale ' 15 limestone, shale 4 - 6 limestone, 3 - 4 conglomerate 14 Sekwi Fm. dolomite, s i l t s t o n e limestone,shale, 12 - 13 s i l t s t o n e , e v a p o r i t e s . q u a r t z i t e 8 - 1 0 dolomite, 3 s i l t s t o n e , d o l o - : s i l t s t o n e , s l a t e mite, q u a r t z i t e 5 - 7 -Rapitan Croup 2 Katherine Fm. 1 p h y l l ^ t e , q u a r t i -ite 206 APPENDIX C CALCULATIONS OF ANALYTICAL PRECISION AND ANALYSES OF VARIANCE 207 APPENDIX C ^ CALCULATIONS OF ANALYTICAL PRECISION AND  ANALYSES OF VARIANCE C.1 A n a l y t i c a l P r e c i s i o n A n a l y t i c a l p r e c i s i o n was calculated for the atomic absorption and commercial mercury analyses only. The atomic absorption method included 17 samples which were analyzed i n t r i p l i c a t e (Figure C - l ) . Each t r i p l i c a t e has been treated as two sets of paired analyses, with one set of pai r s rep-resenting the p r e c i s i o n of combined hand specimen sampling and a n a l y t i c a l procedures ( a n a l y t i c a l set one) and the other set representing a n a l y t i c a l p r e c i s i o n alone ( a n a l y t i c a l set two). Replicate paired sample analyses for each element are l i s t e d i n Table C - l . I t should be noted that only 13 duplicated samples were a v a i l a b l e tootest for a n a l y t i c a l p r e c i s i o n of mercury and that sampling p r e c i s i o n of mercury was not investigated (Table C-lg). I n s u f f i c i e n t data was a v a i l a b l e for p r e c i s i o n estimates of n i c k e l and cobalt r e s u l t s . Table 3-4 records the paired p r e c i s i o n t e s t s . 208 HAND SPECIMEN A2 ' A n a l y t i c a l Check' ' O r i g i n a l Sample' B 'Separation Check' Separation Procedure A n a l y t i c a l Procedure A n a l y t i c a l Set Two A n a l y t i c a l Set One P r e c i s i o n and A n a l y s i s of Variance C a l c u l a t i o n s FIGURE C-l SCHEMATIC DIAGRAM OF SAMPLE SEPARATIONS AND GROUPINGS FOR PRECISION AND ANALYSIS OF VARIANCE CALCULATIONS 209 C.2 Analyses of Variance An analysis of variance i s a s t a t i s t i c a l technique whereby the o v e r a l l v a r i a t i o n within a set of data can be reduced and at t r i b u t e d to a number of component sources of v a r i a b i l i t y . This can be achieved by treating each a n a l y t i c a l r e s u l t as an estimator of the expected mean value plus contribu-tions from various other sources. I f an experiment has a structure which can attempt to define the prime sources, then a measure of each contribution to the v a r i a t i o n of the a n a l y t i c a l r e s u l t about the expected mean can be determined. Hence, a knowledge of the r e l a t i v e s i g n i f i c a n c e of each source w i l l permit the confident u t i l i z a t i o n of the o v e r a l l data set with i n any r e s t r i c t i o n s discovered during the analysis of variance. Further discussion of t h i s technique can be found i n Walpole and Myers (1972) or Koch and Link (1970) . In t h i s experiment, sources of v a r i a b i l i t y to be considered are: 1) a n a l y t i c a l variance versus hand specimen variance (even though t h i s has already been examined within the p r e c i s i o n analysis, i t may be b r i e f l y re-examined within the analysis of variance t a b l e s ) , 2) o v e r a l l a n a l y t i c a l and sampling variances between deposits versus o v e r a l l a n a l y t i c a l and sampling variances within deposits, and 3) the general data v a r i a b i l i t y between deposits i n the region versus the v a r i a b i l i t y of the data w i t h i n eachi of those deposits. Determining the r e l a t i v e importance of the sources i n 2) and 3) i s c r i t i c a l i n defining the character of s p e c i f i c deposits w i t h i n the entire area as a whole. The analysis of variance treatment uses a sum of squares method whereby the t o t a l population variance can be expressed as a sum of the between population variance and the within population variance. Calculations i n t h i s analysis are displayed as a r a t i o of variance between these two 210 FIGURE C-2 TABULATION OF CALCULATIONS FOR AN ANALYSIS OF VARIANCE Degrees of Computed Source Sum of Squares Freedom Mean Square F K r ,—. x2 2 SSB (yx - y) = SSB K - l Sn = rp-r- ... 1=1 F = 1=1 j = l 2 K(n-l) Total ^ ^ ( y i j ~ y) = S S T riK-1 1=1 j = l K = # deposits y l = deposit mean n = # samples y = t o t a l population mean y i j = s i n g l e sample r e s u l t _K_ n 2 Within Z _ ^L _ ( y i j - y D = SSW K(n-l) S = sources, the f i n a l r a t i o having an F - d i s t r i b u t i o n . The equations used (c f . Walpole and Myers, 1972, p. 356) are shown i n Figure C-2, Basic assumptions underlying these tests are that the samples are randomly chosen from a normal population. Trace element data generally follow a log-normal d i s t r i b u t i o n and the sample population used f o r these tests may not s t r i c t l y r e f l e c t the same normal d i s t r i b u t i o n , but w i l l be s u f f i c i e n t l y accurate to ensure a meaningful t e s t ( S i n c l a i r , A.J., 1977, pers. comm.). Therefore, a l l c a l c u l a t i o n s were performed on log-transformed data. Analysis of variance r e s u l t s , c a l culated from data i n Table C - l , are displayed i n Table C-2. The computed F value i s shown, along with the c r i t i c a l F value f o r a sample population of th i s design. A comparison of the mean square values f o r the within sample pair variance of both a n a l y t i c a l sets one and two provides a r a t i o which also follows an F d i s t r i b u t i o n and 211 which y i e l d s information on variance due to hand sampling and analysis versus variance due to analysis alone. Therefore, for each element, the comparison F r a t i o of the two a n a l y t i c a l sets i s also shown, with i t s c r i t i c a l value as w e l l . These r e s u l t s were discussed i n the text r e l a t i v e to the sources of v a r i a b i l i t y considered (refer to Chapter 3, section 3.5). In a l l cases the c r i t i c a l F values were determined using a one sided test at the. 95% confidence l e v e l (Walpole and Myers, 1972, Table V I I ) . It should be noted that only 13 samples were analyzed i n duplicate f o r mercury. Specimens were not independently separated p r i o r to the commercial mercury a n a l y s i s , hence sampling variances can not be c a l c u l a t e d f o r t h i s element. A further test was performed to examine the variance of i n d i v i d u a l specimens themselves, between and w i t h i n deposits. This was to test the hypothesis that the specimens from a s i n g l e deposit can characterize that deposit r e l a t i v e to the v a r i a t i o n s found i n a l l samples across the region. In t h i s case, the nine deposits having a minimum of f i v e specimens each were chosen. From deposits containing more than f i v e specimens, a random s e l e c t i o n of f i v e representatives was made. The r e s u l t s of t h i s analysis are recorded i n Table C-3 f o r each element, p r e c i s e l y as i n the case of sample duplicates, and are discussed i n Chapter 5, section 5.3. V a r i a t i o n of analyses within and between d i s t i n c t colour groups was also investigated using an analysis of variance. Ten samples from each of the four colour categories were used i n t h i s test and the c a l c u l a t i o n s are shown i n Table C-4. Discussion of t h i s data i s l i n Chapter 5, section 5.6, TABLE C-la SEVENTEEN TRIPLICATED SAMPLE ANALYSES ( l i s t e d as a n a l y t i c a l pairs) (recorded i n ppm) Element:Silver A n a l y t i c a l Set One Sample Number 100C6 10024 3 1 10027 2 10033 14 10036 2 10042 1 10042 9 10044 1 20005 4 20008 9 20012 2 20023 96 '20023 126 20024 7 20025 1 20034 20035 1 1 V 13 11 7 295 28 15 • 36 5 4 0 3 3 6 8 0 0 5 B 13 10 • 3 288 27 19 35 5 5 0 3 2 6 •7 0 2 8 n a l y t i c a l Set Two A l , 13 11 7 295 28 15 36 5 4 0 3 3 6 8 0 0 5 A2 12 11 3 290 29 15 37 3 2 0 3 5 7 10 0 0 5 (0= not detected : r e f e r to Table 3^ -3 for detection l i m i t s ) TABLE C-lb • •SEVENTEEN TRIPLICATED SAMPLE ANALYSES ( l i s t e d as a n a l y t i c a l pairs) (recorded i n ppm) ElementtCadmium A n a l y t i c a l Set One Sample Number 10006 3 10024 1 10027 2 10033 14 10036 2 10042 1 10042 9 10044 1 20005 4 20008 9 20012 2 20023 96 20023 126 20024 7 20025 1 20034 1 20035 1 A l 1010 1548 2065 2401 1064 1599 1318 1760 4586 767 1560 2040 2511 1574 1618 1176 1184 B 940 1525 2065 1879 1155 1773 1308 1783 5504 791 1624 1939 2944 1374 1644 1194 1004 A n a l y t i c a l Set Two 1010 1548 "2065 2401 • 1064 1599 1318 1760 4586 767 1560 2040 2511 1574 1618 1176 1184 A 2 942 1327 1926 1953 1022 1618 1426 1755 4524 714 1,453 2048 2393 1539 . 1531 1090 1125 (0= not detected: ref e r to Table 3-3 for detection l i m i t s ) TABLE C-lc SEVENTEEN TRIPLICATED SAMPLE ANALYSES ( l i s t e d as a n a l y t i c a l pairs) (recorded i n ppm) Element:Copper A n a l y t i c a l Set One Sample Number 10006 3 10024 1 10027 2 10033 14 10036 2 10042 1 10042 9 10044 1 20005 4 20008 9 20012 2 20023 96 20023 126 20024 7 20025 1 20034 1 20035 1 A l B 95 103 26 33 140 144 13 16 563 545 280 280 • 271 293 722 740 110 114 8 8 29 31 5 21 12 39 525 .105 73 14 198 192 366 362 l a l y t l c a l Set Two A l 95 26 140 . 13 563 280 271 722 110 8 29 5 12 525 73 198 366 A2 92 29 152 16 558 280 272 733 110 8 29 5 58 519 71 191 367 1(0= not detected: ref e r to Table 3^ -3 for detection l i m i t s ) TABLE C-ld SEVENTEEN TRIPLICATED SAMPLE ANALYSES ( l i s t e d as a n a l y t i c a l pairs) (recorded i n ppm) Element:Iron A n a l y t i c a l Set One Sample 10006 10024 10027 10033 10036 10042 10042 10044 20005 20008 20012 20023 20023. 20024 20025 20034 20035 Number 3 1 2 14 2 1 9 1 4 9 2 96 126 7 1 1 1 _ A l 13280 4976 749 1701 3260 2319 2149 4954 4174 1590 124 421 • 411 117 481 726 290 B 12750 4990 728 1341 3403 2382 2117 5129 3220 1421 104 213 268 145 445 701 176 Analytical Set Two A l 13280 4976 '749 1701 3260 2319 2149 4954 4174 1590 124 421 411 117 481 726 290 A2 12520 5113 765 1739 3235 2957 2261 5391 3722 1426 .97 275 209 90 . 431 633 104 (0= not detected: refer to Table 3-3 for detection l i m i t s ) TABLE C-le SEVENTEEN TRIPLICATED SAMPLE ANALYSES (li s t e d as analytical pairs) (recorded i n ppm) Element:Manganese Analytical Set One Sample Number 10006 10024 3 1 1C027 2 10033 14 10036 2 10042 1 10042 9 10044 1 20005 4 20008 9 20012 2 20023 96 20023 126 20024 7 20025 1 20034 1 20035 1 A l 26 14 11 0 18 58 . 102 22 24 18 50 53. 46 46 8 35 28 B 25 13 10 0 19 62 . 104 24 24 13 39 43 36 .48 8 : 33 24 l a l y t i c a l Set Two A i ;. 26 14 11 . 0 18 58 102 22 24 18 50 53 46 46 8 35 ' 28 A2 30 17 . 10 0 12 .69 122 31 24 18 49 55 49 49 8 36 26 (0= not detected: refer to Table 3^ -3 for detection l i m i t s ) TABLE C-lf •SEVENTEEN TRIPLICATED SAMPLE ANALYSES (li s t e d as analytical pairs) (recorded in ppm) Element:Lead Analytical Set One Sample Number 10006 3 10024 1 10027 2 10033 14 10036 2 10042 1 10042 9 10044 1 20005 4 20008 9 20012 2 20023 96 20023 126 20024 7 20025 1 20034 1 20035 1 A l 3462 870 132 29 50 347 659 309 870 336 . 84 463 573 30 18 56 29 B 3450 802 86 29 47 330 719 286 612 370 92 476 755 13 11 55 19 l a l y t i c a l . Set Two \ 3462 870 • 132 29 50' 347 659 309 870 336 84 463 573 30 18 56 29 A2 3422 904 123 35 42 327 619 317 767 394 110 546 916 22 • ' 16 51 19 (0= not detected: refer to Table 3-3 for detection l i m i t s ) TABLE C-lg THIRTEEN DUPLICATED SAMPLE ANALYSES (recorded in ppm) Element: Mercury Analytical Set Two Sample 10006 10024 10025 10033 10034 10042 20012 20012 20019 20023 20024 20025 20034 Number 2 2 4 ft 1 1 1 4 4 96 8 2 1 _ Al 3.00 215.00 10.05 26.50 10.50 8.80 27.00 27.50 0.29 0.18 2.50 14.50 23.50 A2 5.20 233.00 7.80 25.20 18.00 61.50 25.50 22.00 8.50 0.10 2.30 9.80 19.50 T A B L E C - 2 a A N A L Y S I S O F V A R I A N C E O F T R I P L I C A T E D S A M P L E S E l e m e n t : S i l v e r A n a l y t i c a l S e t O n e S o u r c e S u m o f S q u a r e s D e g r e e s o f F r e e d o m M e a n S q u a r e C o m p u t e d F B e t w e e n 1 2 . 9 9 16 W i t h i n 0 . 1 9 17 0. .81 0 . 0 1 7 0 . 0 2 T o t a l 1 3 . 1 8 3 3 A n a l y t i c a l S e t T w o S o u r c e S u m o f S q u a r e s D e g r e e s o f - F r e e d o m M e a n S q u a r e C o m p u t e d ' F B e t w e e n W i t h i n 1 3 . 7 9 1 6 0 . 1 6 1 7 0 . 8 6 0 . 0 0 9 8 6 . 4 6 T o t a l 1 3 . 9 5 3 3 C r i t i c a l F Q 0 5 ( 1 6 , 1 7 ) 2 . 2 9 C o m p a r i s o n F ( 1 7 , 1 7 ) C r i t i c a l F & 1 7 , 1 7 ) 1 . 2 2 2 . 2 9 T A B L E C - 2 b A N A L Y S I S O F V A R I A N C E O F T R I P L I C A T E D S A M P L E S E l e m e n t : C a d m i u m A n a l y t i c a l S e t O n e S o u r c e S u m o f D e g r e e s o f M e a n C o m p u t e d S q u a r e s F r e e d o m S q u a r e F B e t w e e n 1 . 1 2 16 W i t h i n 0 . 0 2 17 0 . 0 7 0 . 0 0 1 6 5 . 1 1 T o t a l 1 . 1 4 3 3 A n a l y t i c a l S e t T w o S o u r c e B e t w e e n W i t h i n T o t a l S u m o f S q u a r e s D e g r e e s o f ^ F r e e d o m 1 . 0 4 16 0 . 0 1 17 1 . 0 5 3 3 C o m p a r i s o n F ( 1 7 , 1 7 ) 1 . 6 6 -M e a n S q u a r e 0 . 0 7 0 . 0 0 6 C o m p u t e d ' F 1 0 7 . 6 9 C r i t i c a l F 0 > 0 5 ( 1 6 , 1 7 ) 2 . 2 9 C r i t i c a l F & > 0 5 . { 1 7 , 1 7 ) 2 . 2 9 N3 r-• ON T A B L E C - 2 c A N A L Y S I S O F V A R I A N C E O F T R I P L I C A T E D S A M P L E S E l e m e n t : C o p p e r A n a l y t i c a l S e t O n e S o u r c e S u m o f S q u a r e s D e g r e e s o f F r e e d o m M e a n S q u a r e C o m p u t e d F B e t w e e n W i t h i n 1 2 . 6 2 0 . 8 4 1 6 17 0 . 7 9 0 . 0 5 1 5 . 9 9 T o t a l 1 3 . 4 6 A n a l y t i c a l S e t T w o 3 3 S o u r c e S u m o f S q u a r e s D e g r e e s o f • F r e e d o m M e a n S q u a r e C o m p u t e d F B e t w e e n W i t h i n 1 2 . 9 4 0 . 4 3 1 6 1 7 0 . 8 1 0 . 0 3 3 1 . 6 2 T o t a l 1 3 . 3 7 3 3 C r i t i c a l F 0 0 5 ( 1 6 , 1 7 ) 2 . 2 9 C o m p a r i s o n F ( 1 7 , 1 7 ) 1 . 9 6 C r i t i c a l F ^ 0 f r ( 1 7 , 1 7 ) 2 . 2 9 T A B L E C - 2 d A N A L Y S I S O F V A R I A N C E O F T R I P L I C A T E D S A M P L E S E l e m e n t : I r o n A n a l y t i c a l S e t O n e -S o u r c e S u m o f D e g r e e s o f M e a n C o m p u t e d S q u a r e s F r e e d o m S q u a r e F B e t w e e n 1 1 . 6 8 W i t h i n 0 . 1 1 1 6 0 . 7 3 0 . 0 0 6 1 1 7 . 8 8 T o t a l 1 1 . 7 9 3 3 A n a l y t i c a l S e t T w o S o u r c e S u m o f S q u a r e s D e g r e e s o f • F r e e d o m M e a n S q u a r e C o m p u t e d F B e t w e e n 1 2 . 7 2 W i t h i n 1 6 0 . 1 8 17 0 . 7 9 0 . 0 1 7 3 . 6 4 T o t a l 1 2 . 9 0 3 3 C r i t i c a l F 0 0 S ( 1 6 , 1 7 ) 2 . 2 9 C o m p a r i s o n F ( 1 7 . 1 7 ) 0 . 6 0 C r i t i c a l F O 0 f r ( 1 7 , 1 7 ) 2 . 2 9 T A B L E C - 2 e A N A L Y S I S O F V A R I A N C E O F T R I P L I C A T E D S A M P L E S E l e m e n t : M a n g a n e s e A n a l y t i c a l S e t O n e • S o u r c e S u m o f S q u a r e s D e g r e e s o f F r e e d o m M e a n S q u a r e C o m p u t e d F B e t w e e n 3 9 . 6 5 W i t h i n T o t a l 0 . 0 3 . 3 9 . 6 8 A n a l y t i c a l S e t T w o S o u r c e 16 17 3 3 S u m o f S q u a r e s D e g r e e s o f • F r e e d o m 2 . 4 8 . 0 . 0 0 1 M e a n S q u a r e 1 3 4 5 . 7 7 C o m p u t e d F B e t w e e n 4 0 . 2 6 W i t h i n 0 . 0 4 16 17 2 . 5 2 0 . 0 0 2 1 0 6 0 . 3 8 T o t a l 4 0 . 3 2 3 3 C r i t i c a l F 0 < 0 5 ( 1 6 , 1 7 ) 2 . 2 9 C o m p a r i s o n F ( 1 7 , 1 7 ) C r i t i c a l F Q 0 5 ( 1 7 , 1 7 ) 0 . 5 0 2 . 2 9 T A B L E C - 2 f A N A L Y S I S O F V A R I A N C E O F T R I P L I C A T E D S A M P L E S E l e m e n t : L e a d A n a l y t i c a l S e t O n e S o u r c e S u m o f S q u a r e s D e g r e e s o f F r e e d o m M e a n S q u a r e C o m p u t e d F B e t w e e n 1 5 . 5 5 1 6 W i t h i n 0 . 1 5 1 7 T o t a l 1 5 . 7 0 3 3 A n a l y t i c a l S e t T w o S o u r c e B e t w e e n W i t h i n T o t a l S u m o f S q u a r e s D e g r e e s o f - ' F r e e d o m 1 4 . 9 8 16 0 . 0 7 17 1 5 . 0 5 3 3 0 . 9 7 0 . 0 0 8 M e a n S q u a r e 0 . 9 4 0 . 0 0 4 1 1 2 . 9 1 C o m p u t e d F 2 2 8 . 2 8 C r i t i c a l F 0 0 5 ( 1 6 , 1 7 ) t o i — • c o 2 . 2 9 C o m p a r i s o n F ( 1 7 . 1 7 ) C r i t i c a l o f r ( 1 7 , 1 7 ) 2 . 0 0 . 2 . 2 9 T A B L E C -2g ' A N A L Y S I S O F V A R I A N C E O F D U P L I C A T E D S A M P L E S E l e m e n t : M e r c u r y A n a l y t i c a l S e t T w o S o u r c e S u m o f D e g r e e s o f M e a n C o m p u t e d S q u a r e s F r e e d o m S q u a r e F B e t w e e n 1 4 . 5 7 16 ' 1 . 2 1 W i t h i n 1 . 5 5 17 0 . 1 2 T o t a l 1 6 . 1 2 3 3 1 0 . 1 7 C r i t i c a l F Q 0 5 ( 1 1 , 1 2 ) 2 . 7 2 T A B L E C - 3 a A N A L Y S I S O F V A R I A N C E : B E T W E E N A N D W I T H I N D E P O S I T S E l e m e n t : S i l v e r D e p o s i t s . 1 0 0 2 7 1 0 0 3 3 1 0 0 3 7 1 0 0 4 2 2 0 0 1 2 . 2 0 0 2 3 2 0 0 2 4 2 0 0 2 5 2 0 0 3 4 1 4 24 12 7 0 3 5 0 0 2 2 3 9 0 3 8 5 9 0 5 9 0 0 3 2 3 3 3 3 13 5 0 3 2 6 0 4 16 4 16 4 4 0 . 7 0 0 5 2 0 1 5 5 4 3 8 3 1 8 2 19 3 6 ( 0 = n o t d e t e c t e d : r e f e r t o T a b l e 3 - 3 f o r d e t e c t i o n l i m i t s ) S o u r c e S u m o f D e g r e e s o f M e a n C o m p u t e d S q u a r e s F r e e d o m S q u a r e F B e t w e e n 7 5 . 5 6 . 8 9 . 4 7 AO W i t h i n 6 2 . 0 7 3 6 1 . 7 2 T o t a l 1 3 7 . 8 3 4 4 C r i t i c a l F 0 5 ( 8 » 3 ° ) 2 . 2 2 T A B L E C - 3 b A N A L Y S I S O F V A R I A N C E : B E T W E E N A N D W I T H I N D E P O S I T S E l e m e n t : C a d m i u m D e p o s i t s 1 0 0 2 7 1 0 0 3 3 1 0 0 3 7 1 0 0 4 2 2 0 0 1 2 2 0 0 2 3 2 0 0 2 4 2 0 0 2 5 2 0 0 3 4 1 1 5 4 8 1 9 4 3 2 1 0 5 1 8 1 5 1 4 3 6 2 2 4 2 1 7 3 9 • 1 6 4 4 1 1 9 4 . 2 2 0 6 5 1 6 8 0 1 1 4 0 1 4 4 3 1 2 2 3 2 5 6 9 1 3 7 4 1 7 5 2 1 3 8 1 3 2 1 2 3 1 4 6 0 2 2 9 9 1 6 0 5 1 3 8 9 2 0 0 0 1 6 1 5 1 4 0 0 1 1 3 4 4 2 3 5 9 1 5 1 5 1 7 3 3 1 0 4 8 1 1 6 6 1 6 0 8 1 3 7 4 1 4 1 6 1 5 8 4 5 2 2 7 4 1 6 2 2 2 3 7 5 2 8 2 7 1166 2 1 1 4 . 1 6 4 8 1 6 4 1 j 1 -i — 1 0 1 5 ( 0 = n o t d e t e c t e d : r e f e r t o T a b l e 3 - 3 f o r d e t e c t i o n l i m i t s ) S o u r c e S u m o f D e g r e e s o f M e a n C o m p u t e d S q u a r e s F r e e d o m S q u a r e F B e t w e e n 0 . 3 0 W i t h i n 0 . 2 5 3 6 0 . 0 3 0 . 0 0 7 5 . 4 6 to t-o O T o t a l 0 . 5 5 4 4 C r i t i c a l F Q 05(8,36) 2.22 T A B L E C - 3 c A N A L Y S I S O F V A R I A N C E : B E T W E E N A N D W I T H I N D E P O S I T S E l e m e n t : C o p p e r D e p o s i t s 1 0 0 2 7 1 0 0 3 3 1 0 0 3 7 1 0 0 4 2 2 0 0 1 2 2 0 0 2 3 2 0 0 2 4 2 0 0 2 5 2 0 0 3 4 1 1 6 5 4 2 145 3 3 5 .39 2 1 8 . 14 1 9 2 . 2 1 4 4 3 4 3 3 8 9 1 7 1 73 1 3 1 19 .20 2 9 3 1 5 7 2 6 3 3 7 31 1 1 0 5 4 0 2 6 2 1 4 2 2 2 1 8 2 1 8 2 1 4 4 7 9 1 0 5 2 6 5 0 5 2 0 9 1 6 0 5 2 4 3 1 7 2 4 1 4 3 8 6 0 6 8 ( 0 ° n o t d e t e c t e d : r e f e r t o T a b l e 3 - 3 f o r d e t e c t i o n l i m i t s ) S o u r c e S u m o f D e g r e e s o f M e a n C o m p u t e d S q u a r e s F r e e d o m S q u a r e F B e t w e e n 7 . 5 1 8 0 . 9 3 . . : : : 5 . 9 2 W i t h i n 5 . 7 0 3 6 0 . 1 5 T o t a l 1 3 > 2 1 4 4 C r i t i c a l F Q > 0 5 ( 8 , 3 6 ) 2 . 2 2 T A B L E C - 3 d A N A L Y S I S O F V A R I A N C E : B E T W E E N A N D W I T H I N D E P O S I T S E l e m e n t : I r o n D e p o s i t s 1 0 0 2 7 1 0 0 3 3 1 0 0 3 7 1 0 0 4 2 2 0 0 1 2 2 0 0 2 3 2 0 0 2 4 2 0 0 2 5 2 0 0 3 4 1 1 1 3 1 1 7 7 5 2 8 7 3 1 8 9 0 9 2 1 6 5 3 5 7 2 . 4 4 5 7 0 1 . 2 7 2 9 1 8 4 8 6 6 5 4 2 2 6 8 1 0 4 2 1 7 5 2 1 5 7 . 3 4 0 4 6 2 9 3 1 2 4 6 1 0 8 3 3 7 8 1 2 7 5 9 1 1 0 1 6 5 1 9 5 8 1 9 8 8 5 8 0 3 4 2 0 7 7 1 1 5 9 5 2 5 5 5 3 2 1 4 7 2 8 6 1 4 5 1 6 9 3 5 8 7 2 5 2 3 6 8 1 3 0 4 5 0 2 8 2 2 2 0 2 4 1 1 8 5 3 4 0 1 9 0 0 5 5 6 1 ( 0 = n o t d e t e c t e d : r e f e r t o T a b l e 3 - 3 f o r d e t e c t i o n l i m i t s ) S o u r c e S u m o f D e g r e e s o f M e a n C o m p u t e d S q u a r e s . F r e e d o m S q u a r e F B e t w e e n W i t h i n 1 0 . 4 7 1.30 4 . 0 2 3 6 0 . 1 1 1 1 . 7 1 T o t a l 1 4 . 4 9 4 4 C r i t i c a l F Q 0 5 ( 8 , 3 6 ) ho 2 . 2 2 T A B L E C - 3 e A N A L Y S I S O F V A R I A N C E : B E T W E E N A N D W I T H I N D E P O S I T S E l e m e n t : M a n g a n e s e D e p o s i t s 1 0 0 2 7 1 0 0 3 3 1 0 0 3 7 1 0 0 4 2 2 0 0 1 2 2 0 0 2 3 2 0 0 2 4 2 0 0 2 5 2 0 0 3 4 1 13 8 1 0 3 5 1 2 0 3 5 2 8 8 3 3 2 1 0 2 1 6 8 6 2 2 3 5 3 6 .3 2 3 3 13 0 2 5 14 19 3 6 2 4 8 10 A 1 6 2 4 6 ' 5 1 1 8 4 7 4 8 5 15 5 11 0 1 0 3 7 3 1 6 3 6 8 5 11 ( 0 " T i o t d e t e c t e d : r e f e r t o T a b l e 3 - 3 f o r d e t e c t i o n l i m i t s ) S o u r c e S u m o f D e g r e e s o f M e a n C o m p u t e d S q u a r e s F r e e d o m S q u a r e F B e t w e e n 2 5 . 5 9 8 3 . 2 0 : : : 6 . 9 5 W i t h i n 1 6 . 5 8 3 6 0 . 4 6 T o t a l 4 2 . 1 7 4 4 C r i t i c a l F Q 0 5 ( 8 , 3 6 ) 2 . 2 2 T A B L E C - 3 f A N A L Y S I S O F V A R I A N C E : B E T W E E N A N D W I T H I N D E P O S I T S E l e m e n t : L e a d D e p o s i t s 1 0 0 2 7 1 0 0 3 3 1 0 0 3 7 1 0 0 4 2 2 0 0 1 2 2 0 0 2 3 2 0 0 2 4 2 0 0 2 5 2 0 0 3 1 4 5 1 8 3 9 1 7 7 1 1 3 3 6 7 5 5 2 8 1 11 5 5 2 86 1 4 2 3 2 6 1 9 7 2 8 1 4 5 9 7 9 3 .0 8 0 3 5 9 4 6 8 1 8 0 9 9 4 8 3 7 4 6 3 1 4 6 2 1 2 8 4 2 6 6 73 9 5 21 2 8 1 4 7 6 13 12 8 5 7 1 0 0 6 2 1 1 3 0 7 3 2 8 4 7 6 0 0 3 6 4 0 ( 0 = m o t d e t e c t e d : r e f e r t o T a b l e 3 - 3 f o r d e t e c t i o n l i m i t s ) to . NJ N> S o u r c e S u m o f D e g r e e s o f M e a n C o m p u t e d S q u a r e s F r e e d o m S q u a r e F B e t w e e n 1 8 . 5 7 8 2 . 3 2 : '• '• : 2 . 7 7 W i t h i n 3 0 > 1 0 3 6 . Q T o t a l 4 8 . 6 7 44 C r i t i c a l F 0 > 0 5 ( 8 , 3 6 ) 2 . 2 2 T A B L E C - 3 g A N A L Y S I S O F V A R I A N C E : B E T W E E N A N D W I T H I N D E P O S I T S E l e m e n t : M e r c u r y D e p o s i t s 1 0 0 2 7 1 0 0 3 3 1 0 0 3 7 1 0 0 4 2 2 0 0 1 2 2 0 0 2 3 2 0 0 2 4 2 0 0 2 5 2 0 0 3 4 1 1 9 2 . 5 1 2 0 . 5 1 2 . 0 4 5 . 5 2 3 . 5 0 . 2 2 . 2 • 1 2 . 0 2 3 . 5 . 2 2 6 7 . 5 2 6 7 . 0 5 . 0 6 7 . 5 2 2 0 . 5 0 . 7 l'.!0 1 4 . 5 9 . 7 3 2 9 5 . 0 4 6 . 5 8 . 8 1 6 3 . 0 1 2 . 0 0 . 3 3 . 2 1 8 . 5 3 4 . 5 4 2 9 5 . 0 4 4 . 5 8 . 8 7 . 5 2 4 . 0 0 . 4 2 0 . 0 1 2 . 5 2 6 . 0 5 2 9 2 . 5 1 5 4 . 0 7 . 5 6 1 . 0 4 1 . 0 0 . 2 2 . 5 1 7 . 0 2 6 . 5 ( 0 = n o t d e t e c t e d : r e f e r t o T a b l e 3 - 3 f o r d e t e c t i o n l i m i t s ) NJ NJ S o u r c e S u m o f D e g r e e s o f M e a n C o m p u t e d S q u a r e s . F r e e d o m S q u a r e F B e t w e e n 2 9 . 1 4 3 . 6 4 W i t h i n 3 5 . 4 0 3 . 7 0 0 . 1 0 T o t a l 3 2 . 8 4 4 4 C r i t i c a l F 0 > 0 5 ( 8 , 3 6 ) 2.22 T A B L E C - 4 a A N A L Y S I S O F V A R I A N C E : B E T W E E N A N D W I T H I N C O L O U R C A T E G O R I E S E l e m e n t : S i l v e r C o l o u r s D a r k P a l e O r a n g e G r e e n A m b e r A m b e r 1 1 0 . 5 1 . 8 1 5 5 . 3 0 . 0 2 4 . 1 2 . 8 0 . 0 0 . 0 3 6 . 8 2 . 6 3 . 5 0 . 0 4 2 7 . 4 2 . 3 6 . 1 0 . 0 . in , cj 5 §• 6 3 5 . 6 2 3 . 9 0 . 0 0 . 0 5 6 . 6 2 . 9 0 . 0 0 . 0 co 7 8 2 . 8 0 . 0 0 . 0 5 . 2 8 0 . 0 1 6 . 0 1 . 8 2 . 5 9 5 . 5 5 8 . 6 0 . 0 1 . 8 10 6 . 7 1 1 . 1 0 . 0 0 . 0 ( 0 = n o t d e t e c t e d : r e f e r t o T a b l e 3 - 3 f o r d e t e c t i o n l i m i t s ) S o u r c e S u m o f D e g r e e s o f M e a n C o m p u t e d S q u a r e s F r e e d o m S q u a r e F B e t w e e n 6 0 . 4 9 3 2 0 . 1 6 : : • 3 1 - 4 3 W i t h i n 2 3 . 0 9 36 0 . 6 4 T o t a l 8 3 . 5 8 39 C r i t i c a l F Q 0 5 ( 3 , 3 6 ) 2 . 9 0 T A B L E C - 4 b A N A L Y S I S O F V A R I A N C E : B E T W E E N A N D W I T H I N C O L O U R C A T E G O R I E S E l e m e n t : C a d m i u m C o l o u r s D a r k A m b e r P a l e A m b e r O r a n g e G r e e n 1 1 5 4 8 3 4 4 5 1 6 2 2 9 3 0 2 1 5 8 4 4 2 0 0 1 1 3 8 7 1 9 3 • 1 2 0 0 1 2 2 6 2 5 1 1 1 6 2 4 4 1 1 0 0 1 5 2 9 1522 1 2 6 1 8 5 1 3 1 8 1 9 4 3 1 8 4 1 6 9 3 ! 6 2 3 8 8 1 2 0 2 2 0 0 0 1 4 4 1 5 7 2 8 2 7 4 4 6 6 1 9 4 5 2 8 4 1 8 1 3 7 7 1 3 7 4 2 6 0 8 1 5 2 6 9 1 1 6 1 1 6 2 9 2 1 1 4 1 6 4 1 10 1 8 3 6 1 1 9 6 2 3 6 5 1 5 2 8 S o u r c e S u m o f • S q u a r e s D e g r e e s o f F r e e d o m M e a n S q u a r e C o m p u t e d B e t w e e n W i t h i n 0 . 2 2 1 . 0 8 3 6 0 . 0 7 0 . 0 3 2 . 4 8 T o t a l 1 . 3 0 3 9 C r i t i c a l F C > 0 5 ( 3 , 3 6 ) 2 . 9 0 TABLE C-4c A N A L Y S I S O F V A R I A N C E : B E T W E E N A N D W I T H I N C O L O U R C A T E G O R I E S Element: Copper Colours Dark Amber Pale Amber Orange Green 1 26 13 160 31 2 164 10 8 8 3 • 92 18 1732 11 4 571 21 ' 12 16 S 5 271 41 8 40 1* 6 219 13 5 44 o » 7 317 10 6 131 '8 99 19 9 7 9 617 8 4 60 10 297 13 4 210 Source Sum o f Degrees o f Mean Computed Squares Freedom Square F Between 8.16 Within 10.72 36 2.72 0.30 9 . 1 3 T o t a l 18.88 39 C r i t i c a l F 0 0 5 ( 3 , 3 6 ) 2.90 TABLE C-4 d ANALYSIS OF VARIANCE: BETWEEN AND WITHIN COLOUR CATEGORIES Element: Iron Colours Dark Amber Pale Amber Orange Green 1 4976 1712 1304 2500 2 35870 496 720 1304 3 ' 1739 1159 203 2603 4 2149 .986 • 411 1837 u 5 i H 3062 1775 175 1011 §" 6 2220 1087 165 114 " 7 622 1836 183 288 8 3143 2157 236 2022 9 1311 516 185 1900 10 12400 6365 290 2487 NJ Source Sum of Squares Degrees o f Freedom Mean Square Computed F Between Within 5.50 5.89 36 1.83 0.16 11.21 To ta l 11.39 39 C r i t i c a l F 0 0 5 ( 3 , 3 6 ) 2.90 T A B L E C - 4 - e A N A L Y S I S O F V A R I A N C E : B E T W E E N A N D W I T H I N C O L O U R C A T E G O R I E S E l e m e n t : M a n g a n e s e C o l o u r s D a r k A m b e r P a l e A m b e r O r a n g e G r e e n 1 14 0 0 1 3 2 1 3 0 1 5 6 3 8 3 0 2 0 4 1 1 0 4 6 3 m 5 1 0 2 8 3 5 1 5 £ 6 1 1 6 5 3 6 1 4 a « ? 7 3 8 3 4 4 0 8 25 3 6 4 7 8 9 4 . 1 9 3 6 5 10 5 4 9 3 7 5 ( 0 = n o t d e t e c t e d : r e f e r t o T a b l e 3 - 3 f o r d e t e c t i o n l i m i t s ) S o u r c e S u m o f D e g r e e s o f M e a n C o m p u t e d S q u a r e s F r e e d o m S q u a r e F B e t w e e n 6 . 7 8 3 2 . 2 6 3 . ] 5 W i t h i n 2 5 . 8 5 3 6 0 . 7 2 T o t a l 3 2 . 6 3 3 9 C r i t i c a l F 0 Q 5 ( 3 , 3 6 ) 2 . 9 0 T A B L E C - 4 f A N A L Y S I S O F V A R I A N C E : B E T W E E N A N D W I T H I N C O L O U R C A T E G O R I E S E l e m e n t : L e a d C o l o u r s D a r k P a l e O r a n g e G r e e n A m b e r A m b e r 1 8 7 0 2 5 5 0 2 2 9 2 4 5 1 9 1 2 6 3 1 5 8 7 3 . • 3 8 7 9 6 1 2 7 1 1 8 3 4 23 4 2 5 7 3 1 1 6 a -cu 5 6 5 9 8 3 9 5 9 4 7 3 & 6 4 9 7 5 6 4 0 4 6 3 24 a " 7 1 3 0 7 4 8 1 3 2 3 7 6 6 8 2 0 6 7 7 9 3 4 7 6 0 9 1 5 6 2 7 6 0 3 6 10 3 6 71 6 5 0 2 2 ( 0 = n o t d e t e c t e d ' : r e f e r t o T a b l e 3 - 3 f o r d e t e c t i o n l i m i t s ) S o u r c e S u m o f D e g r e e s o f M e a n C o m p u t e d - S q u a r e s F r e e d o m S q u a r e F B e t w e e n 2 . 8 5 3 0 . 9 5 : : '• • 0 . 9 7 W i t h i n 3 5 . 1 6 3 6 0 . 9 8 T o t a l 3 g 0 1 3 9 C r i t i c a l F Q Q 5 ( 3 , 3 6 ) 2 . 9 0 T A B L E C - 4 g A N A L Y S I S O F V A R I A N C E : B E T W E E N A N D W I T H I N C O L O U R C A T E G O R I E S E l e m e n t : M e r c u r y C o l o u r s D a r k P a l e O r a n g e G r e e n A m b e r A m b e r 1 0 . 0 7 . 5 1 5 4 . 0 1 0 . 0 2 1 9 2 . 5 2 . 2 0 . 4 2 . 0 3 . 0 . 0 2 6 . 5 0 . 0 2 . 0 4 8 2 . 5 1 2 0 . 5 0 . 0 0 . 2 m 5 0 . 0 4 0 . 0 0 . 7 . 0 . 0 *-i ! • 6 6 6 . 0 4 4 . 0 0 . 3 2 7 . 5 to to 7 6 1 . 0 0 . 0 0 . 2 0 . 5 8 0 . 0 0 . 0 0 . 4 1 2 . 0 9 6 . 5 no 0 , 2 1 7 . 0 1 0 7 . 8 2 . 3 0 . 2 0 . 1 ( 0 = n o t d e t e c t e d : r e f e r t o T a b l e 3 - 3 f o r d e t e c t i o n l i m i t s ) NJ S o u r c e S u m o f S q u a r e s D e g r e e s o f F r e e d o m M e a n S q u a r e C o m p u t e d F B e t w e e n W i t h i n T o t a l 4 . 0 7 7 6 . 1 9 8 0 . 2 6 3 6 3 9 1 . 3 6 2 . 1 2 0 . 6 4 C r i t i c a l F Q Q 5 ( 3 , 3 6 ) 2 . 9 0 228 APPENDIX D APPLICATION OF PROBABILITY GRAPHS 229 APPENDIX D  APPLICATION OF PROBABILITY GRAPHS The a p p l i c a t i o n of p r o b a b i l i t y graphs to geochemical analyses affords a simple method of p a r t i t i o n i n g the data into d i s t i n c t populations and provides information on each population i n terms of i t s mean, standard deviation, and degree of overlap with neighbouring populations. The method i s w e l l explained by S i n c l a i r (1976) , hence no de t a i l e d discussion i s provided here. In t h i s study the quantitative a n a l y t i c a l r e s u l t s for seven elements ( n i c k e l and cobalt provided i n s u f f i c i e n t data) were p l o t t e d as p r o b a b i l i t y graphs (Figures D-1: a-g). Populations were p a r t i t i o n e d on the basis of i n f l e c t i o n points found i n the curve (designated i n the figures with an arrow). The closed dots i n the figures represent the o r i g i n a l data points, the open c i r c l e s define the plots of each population reconstructed to represent 100% of a data population, and the tr i a n g l e s define a curve reconstructed by i d e a l combination of the p a r t i t i o n e d populations. The percentage of the t o t a l data, the mean, and the standard deviation are given f o r each population. Plots of i n d i v i d u a l populations derived from an o r i g i n a l trimodal d i s t r i b u t i o n are drawn from plots of the A-B and B-C populations, recalculated to 100%. Forty-eight data values (one for each deposit) were analyzed on each pl o t (except mercury which provided 41 values). This s i z e of sample population, which i s r e l a t i v e l y small for analysis by p r o b a b i l i t y graphs, necessitates caution i n i n t e r p r e t a t i o n of the graphs. Nevertheless, the differences i n minor element abundances i n the p a r t i t i o n e d populations are so great i n many cases that the v a l i d i t y of the multi-modal i n t e r p r e t a t i o n s i l l u s t r a t e d i n Figures D-la to D-lg i s undisputable. 230 FIGURE D-la: PROBABILITY GRAPH OF SILVER 231 1 2 6 K> 2 0 30 4 0 6 0 60 7 0 « 0 8 0 98 1* CUMULATIVE P E R C E N T FIGURE D-lb: PROBABILITY GRAPH OF COPPER 232 1 2 6 10 2 0 30 4 0 6 0 60 7 0 60 » 0 SS 9 * * • CUMULATIVE P E R C E N T FIGURE D-ld: PROBABILITY GRAPH OF MERCURY 234 1U 2 0 30 4 0 SO 60 TO CUMULATIVE P E R C E N T » 8 I* FIGURE D-le: PROBABILITY GRAPH OF CABHIUM 235 CUMULATIVE P E R C E N T FIGURE D - l f : PROBABILITY GRAPH OF MANGANESE 236 C U M U L A T I V E P E R C E N T FIGURE D-lg: PROBABILITY GRAPH OF LEAD 

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