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Geology, petrology and precious metal mineralization, Toodoggone River area, north-central British Columbia Forster, Douglas Burton 1984

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GEOLOGY, PETROLOGY AND PRECIOUS METAL MINERALIZATION, TOODOGGONE RIVER AREA, NORTH-CENTRAL BRITISH COLUMBIA By DOUGLAS BURTON FORSTER B . S c , The U n i v e r s i t y o f B r i t i s h Columbia, 1981 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 h e r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA January 1984 © Douglas B u r t o n F o r s t e r , 1984 I n p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r an advanced degree a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I ag r e e t h a t t h e L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by t h e head o f my department o r by h i s o r h e r r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department o f The U n i v e r s i t y o f B r i t i s h C olumbia 1956 Main Mall V a n c ouver, Canada V6T 1Y3 Date " j f ^ fg 19^4" DE-6 (3/81) FRONTSPIECE: View l o o k i n g s o u t h f rom t h e headwaters o f Saunders Creek, showing a f a u l t e d b l o c k o f v i t r i c ash t o l a p i l l i t u f f o f t h e Toodoggone s u i t e . A b s t r a c t The Toodoggone R i v e r area (NTS:94E) i s approximately 300 km n o r t h o f Smithers, i n n o r t h - c e n t r a l B r i t i s h Columbia. E a r l y J u r a s s i c Toodoggone v o l c a n i c s c o n s i s t i n g of c a l c - a l k a l i n e , i n t e r m e d i a t e e x t r u s i v e rocks have a t h i c k n e s s exceeding 1200 m. The o l d e s t members o f the s u i t e are a n d e s i t e flows with minor agglomerate and pumice b r e c c i a . O v e r l y i n g the a n d e s i t e s are voluminous d a c i t i c ash flows c o n s i s t i n g o f v i t r i c ash to l a p i l l i t u f f , v i t r i c - l i t h i c ash t u f f , and v i t r i c - c r y s t a l ash t u f f . A l l a n d e s i t e s are c h a r a c t e r i z e d by p o r p h y r i t i c t e x t u r e s and phenocrysts o f p l a g i o c l a s e , hornblende, b i o t i t e and magnetite. D a c i t e s are d i s t i n g u i s h e d by v i t r o c l a s t i c and d e v i t r i f i c a t i o n t e x t u r e s , fragments o f pumice as w e l l as c r y s t a l s o f q u a r t z , s a n i d i n e , p l a g i o c l a s e , b a s a l t i c hornblende, magnetite and hematite. A n d e s i t e s of the Hazelton Group have a t h i c k n e s s of 900 m and are s i m i l a r to the a n d e s i t e s of the Toodoggone s u i t e . F i v e d i s t i n c t a l t e r a t i o n s t y l e s i d e n t i f i e d w i t h i n the r e g i o n i n c l u d e : p r o p y . l i t i c , z e o l i t i c , i n t e r m e d i a t e to advanced a r g i l l i c , p o t a s s i c and s i l i c i c f a c i e s . In the Toodoggone s u i t e , with, i n c r e a s i n g s i l i c a content CaO, P 2 ° 5 ' T"*"02' F e O ( t o t a l ) , Al-jO^, V, Zr decrease and K,,0 i n c r e a s e s . Element m o b i l i t y d u r i n g low grade metasomatism i s i n d i c a t e d by the wide s c a t t e r of p o i n t s i n the Na20, MgO, Cr, N i , Th, Sr, Rb and Nb v a r i a t i o n diagrams. B r e c c i a t e d and s i l i c i f i e d v e i n s a c t as host to g o l d and s i l v e r m i n e r a l i z a t i o n w i t h i n Toodoggone, Hazelton and T a k l a v o l c a n i c flows and t u f f s . F l u i d i n c l u s i o n s from the Moosehorn and Mt. Graves prospects s u g g e s t t h a t o r e - m i n e r a l s f o r m e d a t t e m p e r a t u r e s of between 232°C and 267°C, w i t h f l u i d s a l i n i t i e s of between 3.3 and 6.5 e q u i v a l e n t w e i g h t p e r c e n t N a C l . M i n e r a l d e p o s i t s formed under l i t h o s t a t i c p r e s s u r e s a t d e p t h s of between 115 m and 225 m. A s e l f - s e a l e d t h r o t t l i n g model a c c o u n t s f o r v a r i a t i o n s i n s a l i n i t y , t e m p e r a t u r e , d e p t h o f f o r m a t i o n , a l t e r a t i o n t y p e s , m e t a l z o n a t i o n as w e l l as d e p o s i t i o n a l mechanisms, and can be u s e d a s an e x p l o r a t i o n g u i d e t o h i d d e n o r e s h o o t s . i v TABLE OF CONTENTS PAGE ABSTRACT i i TABLE OF CONTENTS i v LIST OF TABLES v i i i LIST OF FIGURES i x LIST OF PLATES x i i ACKNOWLEDGEMENTS X V CHAPTER .1: INTRODUCTION 1 1.1 L o c a t i o n and Ac c e s s 1 1.2 P r e v i o u s Work 1 1.3 E x p l o r a t i o n H i s t o r y 4 1.4 O b j e c t i v e s 6 1.5 F i e l d w o r k 6 CHAPTER 2: REGIONAL GEOLOGY 8 2.1 I n t r o d u c t i o n 8 2.2 S t r a t i g r a p h y 8 2.3 S t r u c t u r e 15 CHAPTER 3: GEOLOGY OF THE TOODOGGONE RIVER AREA 16 3.1 I n t r o d u c t i o n 16 3.2 H a z e l t o n Group 16 G e n e r a l Geology 16 P e t r o l o g y 22 A l t e r a t i o n 27 S t r u c t u r e 29 Age and C o r r e l a t i o n 30 V PAGE 3.3 Toodoggone V o l c a n i c s 30 Ge n e r a l Geology 31 P e t r o l o g y 44 A l t e r a t i o n 56 S t r u c t u r e 6 2 Age 64 3.4 I n t r u s i v e Rocks 6 7 Ge n e r a l Geology 67 P e t r o l o g y 6 9 Age 71 3.5 G e o l o g i c a l H i s t o r y 72 CHAPTER 4: CHEMISTRY OF THE TOODOGGONE VOLCANICS 7 6 4.1 I n t r o d u c t i o n 7 6 4.2 C l a s s i f i c a t i o n 77 4.3 V a r i a t i o n Diagrams 84 4.4 C h e m i s t r y o f A l t e r a t i o n 86 4.5 Mesozoic V o l c a n i c S u i t e s i n the Canadian C o r d i l l e r a 96 CHAPTER 5: ECONOMIC GEOLOGY 100 5.1 I n t r o d u c t i o n 100 5.2 P r o s p e c t s and D e p o s i t s 101 Moosehorn Amethyst B r e c c i a Zone 102 S i l v e r p o n d P r o s p e c t 105 Lawyers Amethyst Gold B r e c c i a Zone 108 C l i f f Creek P r o s p e c t 110 Baker Mine 110 v i PAGE Golden Neighbour P r o s p e c t 112 GWP 1 t o 10 P r o s p e c t 113 Mt. Graves P r o s p e c t 115 5.3 F l u i d I n c l u s i o n Geothermometry 12 0 I n t r o d u c t i o n 120 Theory 120 Method o f Study 124 Moosehorn Amethyst B r e c c i a Zone .124 Mt. Graves P r o s p e c t 132 D i s c u s s i o n o f R e s u l t s and Genesis 135 Consequences o f t h e Proposed Model 14 7 5.4 E p i t h e r m a l P r e c i o u s M e t a l D i s t r i c t s o f No r t h A m e r i c a 150 REFERENCES 159 APPENDIX A: WHOLE ROCK ANALYSES 16 8 APPENDIX B: FLUID INCLUSION ANALYSES 181 APPENDIX C: GE0CHEMICAL LABORATORY TECHNIQUES 191 C - l Sample P r e p a r a t i o n and Major Element A n a l y s i s 192 C-2 Trace Element A n a l y s i s 195 C-3 D e t e r m i n a t i o n o f F e r r o u s I r o n 196 C-4 D e t e r m i n a t i o n o f T o t a l Water and 20 0 Carbon D i o x i d e . 20 0 APPENDIX D: FLUID INCLUSION GEOTHERMOMETRY ANALYTICAL TECHNIQUES 206 D - l Sample P r e p a r a t i o n and Documentation D-2 Sample H e a t i n g P r o c e d u r e D-3 Sample F r e e z i n g Procedure D-4 Data I n t e r p r e t a t i o n APPENDIX E: X-RAY DIFFRACTION ANALYTICAL DATA APPENDIX F: PETROGRAPHIC DESCRIPTIONS APPENDIX G: MAPS IN-PQGKST- - > p £ " v i i i LIST OF TABLES Page Ta b l e 2-1: F o r m a t i o n s i n t h e Toodoggone R i v e r Area 11 Ta b l e 3-1: P u b l i s h e d Age Dates f o r t h e Toodoggone V o l c a n i c s and R e l a t e d P l u t o n i c Rocks i n N o r t h - c e n t r a l B.C. 65 Ta b l e 4-1: Meso z o i c V o l c a n i s m i n the Canadian C o r d i l l e r a 98 Ta b l e 5-1: Summary o f F l u i d I n c l u s i o n Data from t h e Mt. Graves and Moosehorn Gold and S i l v e r P r o s p e c t s 126 Ta b l e 5-2: S e l e c t e d E p i t h e r m a l G o l d and S i l v e r D i s t r i c t s i n N o r t h America 153 Ta b l e A - l : Whole Rock A n a l y s e s 171 Ta b l e B - l : F l u i d I n c l u s i o n A n a l y s e s 183 Ta b l e C - l : O p e r a t i n g C o n d i t i o n s f o r XRF Major Element A n a l y s i s 193 i x LIST OF FIGURES Page F i g u r e 1-1: Map o f B r i t i s h Columbia l o c a t i n g t h e Toodoggone R i v e r a r e a , B.C. 2 F i g u r e 1-2: Map o f the Toodoggone R i v e r a r e a showing major g o l d and s i l v e r p r o s p e c t s , and a c c e s s r o u t e s . 3 F i g u r e 2-1: R e g i o n a l g e o l o g i c a l map o f t h e Toodoggone R i v e r a r e a , B.C. 10 F i g u r e 3-1: D i a g r a m a t i c c o m p o s i t e s t r a t i g r a p h i c s e c t i o n o f the Toodoggone R i v e r a r e a , B.C. 32 F i g u r e 3-2: S t r a t i g r a p h i c s e c t i o n o f t h e Toodoggone v o l c a n i c s i n t h e Moosehorn Creek canyon. 4 0 F i g u r e 3-3: S t r a t i g r a p h i c s e c t i o n o f the Toodoggone v o l c a n i c s near t h e GWP 1 t o 10 p r o s p e c t . 4 3 F i g u r e 3-4: T y p i c a l h y d r o t h e r m a l a l t e r a t i o n z o n i n g w i t h i n t h e Toodoggone R i v e r a r e a , B.C. 58 F i g u r e 4-1: Ol-Ne-Qz p r o j e c t i o n f o r Toodoggone and H a z e l t o n v o l c a n i c r o c k s . 78 F i g u r e 4-2: AFM diagram f o r Toodoggone and H a z e l t o n v o l c a n i c r o c k s . 79 F i g u r e 4-3: An-Ab-Or diagram f o r Toodoggone and H a z e l t o n v o l c a n i c r o c k s . 81 F i g u r e 4-4: FeO ( t o t a l ) - M g O - A ^ O ^ diagram f o r Toodoggone and H a z e l t o n v o l c a n i c r o c k s . 82 Page F i g u r e 4-5: Normative p l a g i o c l a s e v e r s u s c o l o u r i n d e x c l a s s i f i c a t i o n . 83 F i g u r e 4-6: Zr/TiC> 2 v e r s u s S i 0 2 c l a s s i f i c a t i o n . F i g u r e 4-7: H a r k e r diagrams f o r TiC»2, MnO, Na 20 and 85 K 2 0 . 87 F i g u r e 4-8: Har k e r diagrams f o r F e O ( t o t a l ) , Mgo, A l 2 0 3 , and CaO. 88 F i g u r e 4-9: H a r k e r diagrams f o r P2°5' C r ' N ^ a n < ^ T n * ^ F i g u r e 4-10: H a r k e r diagrams f o r V, S r , Rb and Ba. 90 F i g u r e 4-11: H a r k e r diagrams f o r Nb and Z r . 91 F i g u r e 4-12: A l t e r a t i o n v e r s u s major element c h e m i s t r y v a r i a t i o n diagram. 92 F i g u r e 4-13: A l t e r a t i o n v e r s u s t r a c e element c h e m i s t r y v a r i a t i o n diagram. 93 F i g u r e 5-1:: Hi s t o g r a m s o f h o m o g e n i z a t i o n t e m p e r a t u r e s f o r f l u i d i n c l u s i o n s i n samples from the Mt. Graves and Moosehorn p r o s p e c t s . 128 F i g u r e 5-2: Histograms o f l a s t m e l t i n g t e m p e r a t u r e s f o r f l u i d i n c l u s i o n s i n samples from t h e Moosehorn and Mt. Graves p r o s p e c t s . 129 F i g u r e 5-3: Drawings o f f l u i d i n c l u s i o n s i n amethyst and c a l c i t e from t h e Moosehorn p r o s p e c t . 130 F i g u r e 5—4: Graph o f l a s t m e l t i n g t e m p e r a t u r e v e r s u s h o m o g e n i z a t i o n t e m p e r a t u r e f o r f l u i d i n c l u s i o n s from t h e Mt. Graves and Moosehorn p r o s p e c t s . 133 x i Page F i g u r e 5-5: D r a w i n g s o f f l u i d i n c l u s i o n s i n a m e t h y s t f r o m t h e Mt. G r a v e s p r o s p e c t . 134 F i g u r e 5-6: C r o s s s e c t i o n o f t h e M oosehorn A m e t h y s t B r e c c i a z o n e . 139 F i g u r e 5-7: M odel f o r t h e f o r m a t i o n o f Toodoggone g o l d and s i l v e r d e p o s i t s b a s e d on p r i m a r y and s e c o n d a r y f l u i d i n c l u s i o n s t u d i e s . 141 F i g u r e 5-8: D epth o f f o r m a t i o n and a l t e r a t i o n z o n i n g o f Toodoggone R i v e r e p i t h e r m a l g o l d and s i l v e r d e p o s i t s . 149 F i g u r e C - l : S c h e m a t i c d r a w i n g o f a p p a r a t u s u s e d f o r d e t e r m i n a t i o n o f t o t a l H 20 and CO,,. 205 x i i LIST OF PLATES Page P l a t e 3- 1: Pumice b r e c c i a 18 P l a t e 3- 2: Flow banding i n hornblende a n d e s i t e 18 P l a t e 3- 3: Mt. Graves s i l i c i f i e d zone 20 P l a t e 3 - 4 : Pyroxene a n d e s i t e flow 21 P l a t e 3- 5: S a u s s u r i t i z a t i o n o f p l a g i o c l a s e phenocryst i n a n d e s i t e flow 21 P l a t e 3- 6: P r e h n i t e pseudomorphing hornblende phenocryst i n a n d e s i t e flow 26 P l a t e 3- 7: Quartz pseudomorphing p l a g i o c l a s e phenocryst i n s i l i c i f i e d a n d e s i t e flow 26 P l a t e 3- 8 : I r o n oxide g r a i n s i n pyroxene phenocryst 28 P l a t e 3- Amygdules of p r e h n i t e , carbonate and c h l o r i t e i n a n d e s i t e x e n o l i t h 28 P l a t e 3- 10: Agglomerate w i t h l a y e r s o f f i n e ash 34 P l a t e 3- 11: Weathered agglomerate and pumice b r e c c i a 35 P l a t e 3- 12: E p i d o t i z e d and hematite s t a i n e d p l a g i o c l a s e phenocryst i n a n d e s i t e flow 37 P l a t e 3- 13: Flow banding i n hornblende a n d e s i t e 27 P l a t e 3- 14: Trachyte flows i n the Moosehorn Creek canyon 39 P l a t e 3- 15: C l i f f s o f v i t r i c ash to l a p i l l i t u f f 39 P l a t e 3- 16: C h l o r i t e r e p l a c i n g p l a g i o c l a s e i n hornblende a n d e s i t e 46 x i i i Page P l a t e 3-17: E p i d o t e and s e r i c i t e r e p l a c i n g p l a g i o c l a s e p h e n o c r y s t s i n a n d e s i t e 46 P l a t e 3-18: Hematite s t a i n e d p l a g i o c l a s e p h e n o c r y s t i n a n d e s i t e 4 7 P l a t e 3-19: M a g n e t i t e r e p l a c i n g b i o t i t e i n a n d e s i t e 4 7 P l a t e 3-20: F l a t t e n e d pumice fragment i n v i t r i c ash t o l a p i l l i t u f f 51 P l a t e 3-21: Embayed q u a r t z c r y s t a l i n v i t r i c ash t o l a p i l l i t u f f 51 P l a t e 3-22: B a s a l t i c h o r n b l e n d e i n v i t r i c ash t o l a p i l l i t u f f 52 P l a t e 3-^23: Hexagonal q u a r t z c r y s t a l i n v i t r i e -c r y s t a l ash t u f f 52 P l a t e 3-24: S p h e r u l i t i c d e v i t r i f i c a t i o n o f v i t r i c -c r y s t a l ash t u f f 60 P l a t e 3-25: Gossan on GWP 1 t o 10 Zone 60 P l a t e 3-26: V e i n s o f l a u m o n t i t e and c a l c i t e i n v i t r i c ash t o l a p i l l i t u f f 63 P l a t e 3-27: R h y o l i t e dyke 68 P l a t e 5-1: B r e c c i a t e d and s i l i c i f i e d t r a c h y t e s o f the Moosehorn Amethyst B r e c c i a zone 104 P l a t e 5-2: C h a l c e d o n i c q u a r t z from t h e Moosehorn p r o s p e c t 104 P l a t e 5-3: Amethyst v e i n from t h e Moosehorn p r o s p e c t 106 P l a t e 5^4: S i l v e r p o n d gossan zone 109 x i v Page P l a t e 5-5 P l a t e 5-6 P l a t e 5-7: P l a t e 5-8 P l a t e 5-9 P l a t e 5-10 P l a t e 5-11: P l a t e D-1 P l a t e I P l a t e I I P l a t e I I I Lawyers Amethyst Gold B r e c c i a Zone Fragments o f a m e t h y s t i n e , j a s p e r o i d a l , and c h a l c e d o n i c q u a r t z from the C l i f f Creek p r o s p e c t Gossanous s i l i c i f i e d zone f o r m i n g r i d g e on t h e GWP 1 t o 10 p r o s p e c t Mt. Graves main zone Stockwork o f m i l k y , c h a l c e d o n i c and minor a m e t h y s t i n e q u a r t z i n a n d e s i t e from th e Mt. Graves p r o s p e c t N a t i v e g o l d , a c a n t h i t e and n a t i v e s i l v e r from t h e Mt. Graves p r o s p e c t N a t i v e g o l d i n t e r g r o w n w i t h p y r i t e from the Mt. Graves p r o s p e c t F l u i d i n c l u s i o n geothermometry a p p a r a t u s Geology o f the Toodoggone R i v e r A r e a , B.C Sample l o c a t i o n s C r o s s s e c t i o n s o f the Toodoggone R i v e r a r e a , B.C. 109 111 114 116 118 118 119 217 i n > s^e-e-k-et-X V Acknowledgements I would l i k e t o e x p r e s s my s i n c e r e a p p r e c i a t i o n t o Dr. K.C. M c t a g g a r t f o r h i s g u i d a n c e and s u p e r v i s i o n of a l l s t a g e s o f t h i s p r o j e c t , and f o r many h e l p f u l d i s c u s s i o n s and s u g g e s t i o n s f o r t h e improvement o f t h e f i n a l m a n u s c r i p t and maps. I would a l s o l i k e t o thank Drs. C.I. Godwin and R.L. A r m s t r o n g f o r t h e i r h e l p d u r i n g t h i s r e s e a r c h . I w o u l d e s p e c i a l l y l i k e t o thank t h e many p e o p l e i n t h e d e p a r t m e n t who h e l p e d i n t h i s p r o j e c t i n c l u d i n g , S. H o r s k y f o r h e l p w i t h X - r a y f l u o r e s c e n c e a n a l y s i s , G.T.Nixon f o r h e l p w i t h major e l e m e n t d a t a r e d u c t i o n , B . C r a n s t o n f o r p r e p a r a t i o n of f l u i d i n c l u s i o n and p e t r o g r a p h i c t h i n s e c t i o n s , G.Hodge f o r d r a u g h t i n g and g r a p h i c a r t s s u g g e s t i o n s , E.Montgomery f o r e v e r y t h i n g Ed does so w e l l , and Kim Hudson f o r h e r s u p e r b d r a u g h t i n g a b i l i t i e s and l i m i t l e s s e n c o u r a g e m e n t . I am a l s o v e r y g r e a t f u l t o t h e s t a f f o f G r e a t W e s t e r n P e t r o l e u m C o r p o r a t i o n and e s p e c i a l l y t o Dr. N.C. C a r t e r f o r g i v i n g me t h e o p p o r t u n i t y t o work i n t h e Toodoggone R i v e r a r e a , and f o r many h e l p f u l d i s c u s s i o n s . 1 CHAPTER 1 INTRODUCTION 1.1 L o c a t i o n and A c c e s s The Toodoggone R i v e r a r e a , c e n t e r e d n e a r l o n g i t u d e 127°07'west and l a t i t u d e 5 7 ° 1 9 ' n o r t h (NTS:94E), i s a p p r o x i m a t e l y 300 km n o r t h o f S m i t h e r s B r i t i s h C o l u m b i a a t t h e e a s t e r n m a r g i n o f t h e I n t e r m o n t a n e B e l t ( F i g u r e 1-1). A c c e s s t o t h e r e g i o n i s v i a f i x e d - w i n g a i r c r a f t f r o m S m i t h e r s t o S t u r d e e a i r s t r i p , a g r a v e l runway 1620 m e t r e s l o n g , o r by f l o a t p l a n e t o Toodoggone Lake ( F i g u r e 1-2). From S t u r d e e s t r i p t h e B a k e r mine and L a w y e r s p r o p e r t i e s c a n be r e a c h e d u s i n g a newly c o m p l e t e d (1982) 4-wheel d r i v e r o a d ( F i g u r e 1-2). 1.2 P r e v i o u s Work C a r t e r (1972) gave t h e i n f o r m a l name, and d e s c r i b e d t h e r o c k s and m i n e r a l i z a t i o n w i t h i n t h e Toodoggone v o l c a n i c b e l t . C a r t e r ' s g e o l o g i c a l mapping was c o n f i n e d t o t h e v o l c a n i c r o c k s of t h e L a t e T r i a s s i c T a k l a G roup, a d j a c e n t t o t h e C h a p p e l l e g o l d and s i l v e r p r o s p e c t (now Baker m i n e ) , a l t h o u g h he d i d some work on t h e Toodoggone s u i t e a s w e l l . Toodoggone r o c k s , w h i c h have n o t been g i v e n G r o u p o r F o r m a t i o n s t a t u s , u n c o n f o r m a b l y o v e r l i e t h e T a k l a G r o u p and a r e d e s c r i b e d as i n c l u d i n g d a c i t i c t o l a t i t i c p o r p h y r y f l o w s and p y r o c l a s t i c s of E a r l y J u r a s s i c age (K-Ar 189+6 Ma). G e o l o g i c a l r e c o n n a i s s a n c e mapping by t h e G e o l o g i c a l S u r v e y o f Canada r e s u l t e d i n t h e p u b l i c a t i o n of a 1:250,000 Open F i l e map ( G a b r i e l s e e t a l . , 1976). The map i n c l u d e s 2 FIGURE 1-1: Map o f B r i t i s h Columbia l o c a t i n g t h e Toodoggone R i v e r a r e a . 3. FIGURE 1-2: Map o f t h e Toodoggone R i v e r a r e a showing major g o l d and s i l v e r p r o p e r t i e s and . a c c e s s r o u t e s . 4 t h e Toodoggone map-sheet (NTS:94E) and shows t h e Toodoggone v o l c a n i c s u n d e r l y i n g a b e l t a p p r o x i m a t e l y 70 km l o n g and 15 km w ide. G e o l o g i c a l S u r v e y o f Canada work by R i c h a r d s ( 1 9 7 4 a ) , T i p p e r e t a l . , (1976) and Monger (1977) on t h e T r i a s s i c and J u r a s s i c s t r a t i g r a p h y o f t h e C a n a d i a n C o r d i l l e r a s u p p l e m e n t s t h e work of G a b r i e l s e e_t a l . ( 1 9 7 6 ) . The B r i t i s h C o l u m b i a M i n i s t r y of E n e r g y , M i n e s and P e t r o l e u m R e s o u r c e s has p u b l i s h e d most of t h e p a p e r s on t h e Toodoggone v o l c a n i c s and a s s o c i a t e d e p i t h e r m a l p r e c i o u s m e t a l m i n e r a l i z a t i o n . S c h r o e t e r (1981, 1982, 1983) d e s c r i b e s t h e s t y l e s and t y p e s o f m i n e r a l i z a t i o n as b e i n g t y p i c a l l y e p i t h e r m a l s i l i c i f i e d z o n e s o r v e i n s w i t h i n d a c i t i c t o a n d e s i t i c f l o w s . P a n t e l e y e v (1982, 1983) c o n c e n t r a t e d on r e g i o n a l mapping and s t r a t i g r a p h y w i t h i n t h e Toodoggone v o l c a n i c s , H i s 1:25,000 s c a l e map d e p i c t s a t h i c k s e q u e n c e o f d a c i t i c , t r a c h y t i c and a n d e s i t i c c r y s t a l a s h - f l o w t u f f s , f l o w s , and r e l a t e d e p i c l a s t i c r o c k s t h a t have u n d e r g o n e a p e r i o d of n o r m a l b l o c k f a u l t i n g . B a c h e l o r t h e s e s a t The U n i v e r s i t y of B r i t i s h C o l u m b i a by Erdman ( 1 9 7 8 ) , Uher (1982) and P e t e r ( 1 9 8 3 ) , as w e l l a s numerous p r i v a t e company r e p o r t s on s p e c i f i c e p i t h e r m a l p r o s p e c t s , augment t h e p u b l i s h e d l i t e r a t u r e c o n c e r n i n g t h e Toodoggone v o l c a n i c s . 1.3 E x p l o r a t i o n H i s t o r y A The e a r l i e s t r e c o r d e d m i n e r a l e x p l o r a t i o n i n t h e Toodoggone r e g i o n d a t e s back t o t h e e a r l y 1930's when p l a c e r g o l d c l a i m s were worked a t t h e j u n c t i o n of M c C l a i r C r e e k and 5 t h e Toodoggone R i v e r ( P l a t e I ) . L e a d - z i n c m i n e r a l i z a t i o n i n s k a r n was a l s o e x p l o r e d a t t h i s t i m e by Cominco L t d a l t h o u g h t h e c l a i m s were l a t e r d r o p p e d . F u r t h e r e x p l o r a t i o n i n t h e a r e a was m i n i m a l u n t i l t h e l a t e 1960's when l a r g e t o n n a g e , low g r a d e p o r p h y r y c o p p e r and molybdenum p r o s p e c t s were s t a k e d by Cominco L t d . , Kennco E x p l o r a t i o n (Canada) L t d . , Conwest E x p l o r a t i o n L t d . , and C o r d i l l e r a n E n g i n e e r i n g L t d . In 1969 w h i l e f o l l o w i n g - u p a m o l y b d e n u m - s i l v e r anomaly, a p r o s p e c t o r w o r k i n g f o r Kennco f o u n d some p y r i t i c q u a r t z f l o a t w h i c h , when a n a l y z e d , a s s a y e d 77 g p e r t o n n e g o l d and 1765 g p e r t o n n e s i l v e r ( B a r r , 1978). D u p o n t ' s Baker mine ( f o r m e r l y c a l l e d t h e C h a p p e l l e d e p o s i t ) w h i c h opened i n 1980, now s t a n d s on t h e s i t e of t h i s f i r s t l o d e g o l d d i s c o v e r y i n t h e Toodoggone r e g i o n . The mine has a n n o unced r e s e r v e s o f 90,718 t o n n e s o f 25.5 g p e r t o n n e g o l d and 594 g p e r t o n n e s i l v e r ( S c h r o e t e r , 1981). The L a w y e r s p r o p e r t y b e i n g e x p l o r e d by SEREM L t d was s t a k e d a t a b o u t t h i s t i m e and c o n s i s t s of t h e A m e t h y s t G o l d B r e c c i a (AGB) Zone, and t h e C l i f f C r e e k Zone; t h e p r o p e r t y i s p r e s e n t l y i n t h e f e a s i b l i t y s t a g e o f e x p l o r a t i o n ( C h a p t e r 5 . 2 ) . The 1970's saw l i t t l e e x p l o r a t i o n i n t h e a r e a e x c e p t on t h e C h a p p e l l e and L a w y e r s p r o p e r t i e s . E x p l o r a t i o n i n c r e a s e d s h a r p l y i n 1980 w i t h an i n c r e a s e i n g o l d p r i c e s . In 1981 G r e a t W e s t e r n P e t r o l e u m C o r p o r a t i o n s t a k e d a number of c l a i m s t o c o v e r open g r o u n d . S u b s e q u e n t g e o c h e m i c a l p r o s p e c t i n g d e l i n e a t e d t h r e e main z o n e s o f i n t e r e s t ; t h e M oosehorn Amethyst B r e c c i a Zone, Mt. G r a v e s Zone and t h e GWP 1 t o 10 z o n e . G r e a t W e s t e r n P e t r o l e u m C o r p o r a t i o n a l s o 6 a c q u i r e d t h e S i l v e r p o n d p r o p e r t y t h r o u g h an o p t i o n agreement w i t h Chuck K o w a l l , a w e l l - k n o w n p r o s p e c t o r . The summers of 1982 and 1983 b r o u g h t h e i g h t e n e d e x p l o r a t i o n t o t h e Toodoggone r e g i o n ; t h e l i s t o f c o m p a n i e s a c t i v e l y i n v o l v e d i n e x p l o r a t i o n i n c l u d e : T a i g a C o n s o l i d a t e d L t d . , Du Pont E x p l o r a t i o n o f Canada L t d . , L a c a n a M i n i n g C o r p o r a t i o n L t d . , K i d d C r e e k M i n e s L t d . , Newmont E x p l o r a t i o n of Canada L t d . , G r e a t W e s t e r n P e t r o l e u m C o r p o r a t i o n , SEREM L t d . , G o l d e n R u l e R e s o u r c e s L t d . , and Cominco L t d . 1.4 O b j e c t i v e s T h i s f i e l d and l a b o r a t o r y s t u d y o f t h e Toodoggone v o l c a n i c s was d e s i g n e d t o i n v e s t i g a t e t h e n a t u r e of t h e v o l c a n i c r o c k s and t h e i r r e l a t i o n s h i p t o p r e c i o u s m e t a l m i n e r a l i z a t i o n i n t h e r e g i o n o f F i g u r e 1-2. The o b j e c t i v e s were: 1) t o map t h e l i t h o l o g i c a l c h a r a c t e r i s t i c s of t h e Toodoggone v o l c a n i c b e l t , 2) t o d e t e r m i n e t h e m i n e r a l o g i c a l and c h e m i c a l c h a r a c t e r i s t i c s o f t h e Toodoggone v o l c a n i c s , 3) t o d e t e r m i n e p r e c i o u s m e t a l m i n e r a l o g y and h y d r o t h e r m a l a l t e r a t i o n p a t t e r n s , 4) t o a t t e m p t t o d e f i n e t h e d e p t h o f f o r m a t i o n and g e n e s i s of g o l d and s i l v e r o c c u r r e n c e s w i t h t h e a i d of f l u i d i n c l u s i o n s , 5) t o s y n t h e s i z e a l t e r a t i o n , m i n e r a l o g i c a l and f l u i d i n c l u s i o n d a t a i n t h e form of an e x p l o r a t i o n model, and 6) t o compare t h e Toodoggone r e g i o n w i t h o t h e r e p i t h e r m a l g o l d / s i l v e r d i s t r i c t s . 1.5 F i e l d w o r k W h i l e employed by G r e a t W e s t e r n P e t r o l e u m C o r p o r a t i o n 7 during the summers of 1981 and 1982, approximately 220 square km of the Toodoggone v o l c a n i c b e l t were g e o l o g i c a l l y mapped. Base maps at 1:10,000 were used i n the f i e l d to reco r d geology; a l l data were t r a n s f e r r e d to a 1:25,000 map of the r e g i o n f o r f i n a l c o m p i l a t i o n . Although the e n t i r e t h e s i s area was mapped, d e t a i l e d examination of g o l d and s i l v e r occurrences was r e s t r i c t e d to Great Western Petroleum C o r p o r a t i o n p r o p e r t i e s . 8 CHAPTER 2 REGIONAL GEOLOGY 2.1 I n t r o d u c t i o n The Toodoggone v o l c a n i c s o c c u r i n a n o r t h w e s t e r l y t r e n d i n g b e l t bounded on t h e e a s t by t h e Omineca M o u n t a i n s and on t h e west by t h e S t i k i n e P l a t e a u ( F i g u r e 2 - 1 ) . Pre-Toodoggone r o c k s w i t h i n t h e r e g i o n i n c l u d e P e r m i a n c a r b o n a t e s o f t h e A s i t k a G r o u p and L a t e T r i a s s i c T a k l a v o l c a n i c s . H a z e l t o n Group v o l c a n i c s o c c u r i n f a u l t c o n t a c t w i t h Toodoggone r o c k s and were d e p o s i t e d i n a v o l c a n i c a r c e n v i r o n m e n t d u r i n g t h e E a r l y J u r a s s i c . Omineca i n t r u s i o n s o f T r i a s s i c t o J u r a s s i c age i n v a d e a l l p r e - C r e t a c e o u s r o c k s w i t h i n t h e r e g i o n . Toodoggone r o c k s a r e u n c o n f o r m a b l y o v e r l a i n t o t h e s o u t h w e s t by s e d i m e n t s o f t h e C r e t a c e o u s - T e r t i a r y S u s t u t G r o u p a n d ' M i d d l e t o L a t e J u r a s s i c Bowser G r o u p ( F i g u r e 2 - 1 ) . L i t h o l o g i c a l G r o u p s o f t h e Toodoggone R i v e r a r e a a r e l i s t e d i n T a b l e 2-1. 2.2 S t r a t i q r a p h y A s i t k a G r o u p Wedge-shaped s l i c e s of P e r m i a n A s i t k a , G roup l i m e s t o n e , m a r b l e , c h e r t and minor a r g i l l a c e o u s s a n d s t o n e a r e t h e o l d e s t r o c k s e x p o s e d w i t h i n t h e Toodoggone R i v e r a r e a ( S c h r o e t e r , 1982). A s i t k a r o c k s r e a c h s e v e r a l t h o u s a n d f e e t i n t h i c k n e s s , 30 km t o t h e s o u t h , i n t h e M c C o n n e l l C r e e k map-sheet (NTS:94D; L o r d , 1948). In t h e Toodoggone r e g i o n , pods o f A s i t k a m a r b l e t h r u s t o v e r T a k l a and Toodoggone r o c k s r e a c h o n l y 150 m i n t h i c k n e s s . S k a r n s a r e d e v e l o p e d where 9 LEGEND FIGURE 2-1 S U S T U T G R O U P ! T e r t i a r y - C r e t a c e o u s B O W S E R G R O U P M i d d l e - L a t e J u r a s s i c • • • • • • o o • o • a c T O O D O G G O N E V O L C A N I C S : E a r l y J u r a s s i c H A Z E L T O N GROUP* E a r l y J u r a s s i c T A K L A G R O U P ! L a t e T r i a s s i c r r —T "1 + + + f + + ^ O N I N E C A INTRUSIONS^ L a t e T r i a s s i c - E a r l y J u r a s s i c 3 S A S I T K A G R O U P : P e r m i a n Geologic Contac t (approx imate) Fault (approx imate) Major Dra inages T h e s i s A r e a 10 + + + •+ VD ••••!+ + + + + + \ o • " • •/• + \t. + + + +'\D • r' + + ' ' + + + + * i D ' h - + . + + + \ • / + " + + + + \ o | + + S C A L E K M FIGURE 2-1: R e g i o n a l g e o l o g i c a l map o f the Toodoggone R i v e r a r e a . The s t u d y - a r e a i s o u t l i n e d i n b l a c k ., ( M o d i f i e d a f t e r G a b r i e l s e e t a l . , 19.76) . 11 TABLE 2-1 Formations i n the Toodoggone River Area Era Epoch and Period Group Formation Lithqlogy Cenozoic T e r t i a r y to Sustut Tango Creek pebble conglomerates, sandstones Mesozoic Cretaceous U N C O N F 0 R M I T V Late Jurassic Bowser shales, sandstones chert-pebble conglomerate TT N o o N F 0 R M T T V Early to Middle Jurassic Toodoggone-'-d a c i t i c v i t r i c t u f f s andesite flows and t u f f s trachyte flows agglomerates volcanic greywackes Hazelton Telkwa an d e s i t i c flows, t u f f s , breccias Early Jurassic to • T r i a s s i c Omineca Intrusives granodiorite, quartzmonzonite, d i o r i t e T T O O O N P O R M . • U N C O N F O R M I T Y Late T r i a s s i c Takla Savage Mountain po r p h y r i t i c andesite p y r o c l a s t i c breccia tremolite andesite f i n e grained andesite II N' C 0 N F 0 R M T T Paleozoic Permian As i t lea marble, limestone chert, skarn 1. Toodoggone volcanics have not been given Group or Formation status. 12 Omineca i n t r u s i v e s i n v a d e A s i t k a c a r b o n a t e s . Monger (1977) from work i n t h e M c C o n n e l l C r e e k a r e a , s t a t e d t h a t t h e s e l i m e s t o n e s a r e t h e l o w e s t members i n t h e A s i t k a Group, and a r e o v e r l a i n by b a s a l t s and f l o w banded r h y o l i t e s . T a k l a G r o u p L a t e T r i a s s i c T a k l a v o l c a n i c s a r e r e s t r i c t e d t o t h e s o u t h e r n b o r d e r of t h e s t u d y - a r e a ( F i g u r e 2 - 1 ) . Toodoggone r o c k s a p p e a r t o be s t r u c t u r a l l y c o n f o r m a b l e w i t h t h e u n d e r l y i n g T a k l a G r o u p a l t h o u g h p o s s i b l y t h e r e i s a s l i g h t a n g u l a r u n c o n f o r m i t y . B a r r (1978) r e c o g n i z e d f o u r l i t h o l o g i e s w i t h i n t h e r e g i o n s u r r o u n d i n g t h e Baker mine ( P l a t e I ) , w h i c h from o l d e s t t o y o u n g e s t a r e : 1) a t r e m o l i t e a n d e s i t e p o r p h y r y t h a t t y p i c a l l y has 3-4 mm e u h e d r a l t r e m o l i t e n e e d l e s i n a d a r k g r e y groundmass of p r e d o m i n a n t l y o l i g o c l a s e and m a g n e t i t e , 2) a m a s s i v e , l i g h t g r e e n a p h a n i t i c a n d e s i t e o v e r l i e s t h e t r e m o l i t e p o r p h y r y and t y p i c a l l y c o n t a i n s 1 mm a n h e d r a l f e l d s p a r p h e n o c r y ' s t s w i t h m i n o r p y r i t e and m a g n e t i t e , 3) p o r p h y r i t i c a n d e s i t e i n t h e r e g i o n i s c h a r a c t e r i z e d by 2 mm s u b h e d r a l f e l d s p a r s and a u g i t e p h e n o c r y s t s . i n a f i n e g r a i n e d m a t r i x o f m a i n l y p l a g i o c l a s e and p y r o x e n e s , and 4) a p y r o c l a s t i c b r e c c i a composed of l a p i 1 1 i - s i z e d c l a s t s o f a n d e s i t e i n a p o o r l y s o r t e d g r e e n - g r e y m a t r i x . A l t e r a t i o n s t y l e s w i t h i n t h e T a k l a r o c k s i n c l u d e : e p i d o t i z a t i o n of p l a g i o c l a s e and m a f i c g r a i n s , s e r i c i t i z a t i o n o f f e l d s p a r s , c h l o r i t i z a t i o n o f a u g i t e p h e n o c r y s t s and s i l i c i f i c a t i o n o f a l l c o n s t i t u e n t m i n e r a l s a d j a c e n t t o q u a r t z v e i n s . In a d d i t i o n , f r a c t u r e 13 c o n t r o l l e d l a u m o n t i t e and a n h y d r i t e m i n e r a l i z a t i o n i s w i d e s p r e a d i n T a k l a v o l c a n i c s . T a k l a r o c k s i n t h e Toodoggone r e g i o n would a p p e a r t o c o r r e l a t e w i t h t h e b a s a l t i c Savage M o u n t a i n F o r m a t i o n as d e f i n e d by Monger ( 1 9 7 7 ) . However, c h a r a c t e r i s t i c p i l l o w s t r u c t u r e s n o t e d i n t h e Savage M o u n t a i n F o r m a t i o n have n o t been i d e n t i f i e d i n t h e T a k l a G roup of t h e Toodoggone R i v e r a r e a . H a z e l t o n G r o u p E a r l y J u r a s s i c H a z e l t o n v o l c a n i c s t r e n d n o r t h w e s t e r l y o v e r a l e n g t h of 35 km and a w i d t h of 15 km t o t h e n o r t h e a s t of t h e Toodoggone v o l c a n i c b e l t . R ocks o f t h e H a z e l t o n G roup, w h i c h a r e i n f a u l t c o n t a c t w i t h Toodoggone r o c k s and u n c o n f o r m a b l y o v e r l i e T a k l a v o l c a n i c s , f o r m a s e r i e s of v a r i c o l o u r e d a n d e s i t i c t o d a c i t i c f l o w s , . b r e c c i a s and r e l a t e d e p i c l a s t i c s e d i m e n t a r y r o c k s . F o u r d i s t i n c t s t r a t i g r a p h i c s u b d i v i s i o n s , w i t h a t o t a l t h i c k n e s s o f o v e r 900 m, have been i d e n t i f i e d i n t h e s t u d y - a r e a . T h e s e u n i t s a r e d e t a i l e d i n C h a p t e r 3. Toodoggone V o l c a n i c s E a r l y J u r a s s i c Toodoggone v o l c a n i c r o c k s u n c o n f o r m a b l y o v e r l i e T a k l a v o l c a n i c s . Toodoggone r o c k s f o r m a d i s t i n c t i v e map u n i t c o n s i s t i n g of a n d e s i t i c and d a c i t i c v o l c a n i c f l o w s , p y r o c l a s t i c f l o w and a s h - f a l l d e p o s i t s , as w e l l as m i n o r l a h a r s , b r e c c i a s and l e n s e s o f e p i c l a s t i c s e d i m e n t a r y r o c k s . 14 E l e v e n d i s t i n c t s t r a t i g r a p h i c s u b d i v i s i o n s w i t h a t o t a l t h i c k n e s s e x c e e d i n g 1 2 0 0 m, h a v e b e e n i d e n t i f i e d i n t h e T o o d o g g o n e R i v e r a r e a , a n d t h e s e a r e d e s c r i b e d i n d e t a i l i n C h a p t e r 3 . B o w s e r G r o u p T h e B o w s e r G r o u p o f M i d d l e t o L a t e J u r a s s i c a g e c o n s i s t s o f n o n - m a r i n e a n d m a r i n e b l a c k s h a l e , q u a r t z o s e s a n d s t o n e a n d c h e r t - p e b b l e c o n g l o m e r a t e s w h i c h w e r e d e p o s i t e d i n t h e B o w s e r B a s i n , a s u c c e s s o r b a s i n t o t h e H a z e l t o n T r o u g h ( T i p p e r a n d R i c h a r d s , 1 9 7 6 ) . C l a s t i c r o c k s a r e f o u n d i n t e r b e d d e d w i t h v o l c a n i c f l o w s a n d t u f f s o f t h e H a z e l t o n G r o u p a l o n g t h e m a r g i n s o f t h e b a s i n ( E i s b a c h e r , 1 9 7 1 ) . S u s t u t G r o u p S u s t u t G r o u p c h e r t - p e b b l e c o n g l o m e r a t e o f C r e t a c e o u s - T e r t i a r y a g e u n c o n f o r m a b l y o v e r l i e s T o o d o g g o n e v o l c a n i c r o c k s i n t h e s o u t h w e s t r e g i o n o f t h e s t u d y - a r e a . T h e s e r o c k s c o r r e l a t e w i t h t h e T a n g o C r e e k F o r m a t i o n , d e s c r i b e d b y E i s b a c h e r ( 1 9 7 1 ) a s b e i n g f l u v i a l g r a v e l s d e p o s i t e d b y h i g h g r a d i e n t b r a i d e d s t r e a m s . O m i n e c a I n t r u s i v e s T r i a s s i c t o E a r l y J u r a s s i c O m i n e c a s t o c k s i n v a d e T a k l a , H a z e l t o n , T o o d o g g o n e a n d A s i t k a g r o u p s w i t h i n t h e T o o d o g g o n e R i v e r a r e a . T h e r o c k s r a n g e i n c o m p o s i t i o n f r o m g r a n o d i o r i t e t o d i o r i t e w i t h q u a r t z m o n z o n i t e p h a s e s b e i n g 15 most a b u n d a n t . T h e s e i n t r u s i o n s , t h o u g h t t o be c o e v a l w i t h t h e Toodoggone v o l c a n i c s , a r e p r o b a b l y r e s p o n s i b l e f o r c i r c u l a t i n g h y d r o t h e r m a l f l u i d s w h i c h l o c a l i z e d p r e c i o u s m e t a l m i n e r a l i z a t i o n w i t h i n t h e r e g i o n ( S c h r o e t e r , 1981). 2.3 S t r u c t u r e The Toodoggone R i v e r a r e a i s r i d d l e d w i t h n o r m a l f a u l t s o f E a r l y J u r a s s i c t o T e r t i a r y a g e . Some major f a u l t s y s t e m s e x t e n d f o r t e n s of km ( S c h r o e t e r , 1982; G a b r i e l s e e t a l . , 1976). Most f a u l t s t r e n d n o r t h - n o r t h w e s t t o n o r t h - n o r t h e a s t and d i p s t e e p l y . Low a n g l e t h r u s t i n g d u r i n g t h e M i d d l e J u r a s s i c p l a c e d P e r m i a n A s i t k a G roup m a r b l e s on t o p o f T r i a s s i c T a k l a and J u r a s s i c Toodoggone v o l c a n i c s ( C a r t e r , 1972). Toodoggone r o c k s o f t h e s t u d y - a r e a a r e g e n t l y f l e x e d and have s h a l l o w d i p s t o t h e w e s t . T a k l a and H a z e l t o n v o l c a n i c s have much g r e a t e r d i p s t o w a r d s t h e n o r t h and n o r t h e a s t r e s p e c t i v e l y ( P l a t e I ) . In t h e s o u t h w e s t o f t h e same r e g i o n , S u s t u t c o n g l o m e r a t e s d i p 12 d e g r e e s t o t h e s o u t h w e s t , and do not a p p e a r t o have undergone any major s t r u c t u r a l d i s r u p t i o n s o t h e r t h a n m i n o r open f o l d i n g . N o r m a l , b l o c k f a u l t s w i t h i n t h e Toodoggone R i v e r a r e a may have c h a n n e l e d h y d r o t h e r m a l s o l u t i o n s , r e s u l t i n g i n t h e l o c a l i z a t i o n of g o l d and s i l v e r m i n e r a l i z a t i o n . 16 CHAPTER 3 GEOLOGY OF THE TOODOGGONE RIVER AREA 3.1 I n t r o d u c t i o n The Toodoggone v o l c a n i c s are the main focus of t h i s study, although some time was spent mapping v o l c a n i c s of the Hazelton Group, which a l s o occur w i t h i n the r e g i o n . Outcrop i s abundant above 1500 m; f l u v i a l g r a v e l s and overburden obscure the geology below t h i s e l e v a t i o n . The geology of the Takla v o l c a n i c s adjacent to the Baker g o l d and s i l v e r mine i s a b s t r a c t e d from Barr (1978); geology of the Toodoggone River area i s o u t l i n e d i n P l a t e I. 3.2 Hazelton Group V o l c a n i c and v o l c a n o c l a s t i c rocks of the Hazelton Group have been d i v i d e d i n t o four map u n i t s on the b a s i s of m i n e r a l o g i c a l and t e x t u r a l c h a r a c t e r i s t i c s . These rocks are best viewed on Mt Graves i n the north-east p o r t i o n of the study-area, where over 900 m of v o l c a n i c flow and p y r o c l a s t i c d e p o s i t s are exposed. General Geology Un i t 7 Par t l y - w e l d e d a n d e s i t e pumice b r e c c i a ( u n i t 7 on P l a t e I) comprises the o l d e s t u n i t of the Hazelton v o l c a n i c s i n the study-area. T h i s p y r o c l a s t i c d e p o s i t crops out at an e l e v a t i o n of 1600 m on the southwest f l a n k of Mt. Graves, where i t forms rough, blocky outcrops and ranges i n t h i c k n e s s from 90 to 275 m. Maroon to brown b r e c c i a 1 7 fragments range i n s i z e from 4 to 100 cm but most are subangular to subrounded blocks averaging 6 to 15 cm i n diameter ( P l a t e 3-1). Formed as a p y r o c l a s t i c flow t h i s d e p o s i t i s unbedded and unsorted; where i t i s i n t r u d e d by quartz monzonite sto c k s i t i s a r g i l l i c a l l y a l t e r e d and extremely f r i a b l e . U n i t 8 Green to grey-green hornblende a n d e s i t e flows o v e r l i e the pumice b r e c c i a and have a t o t a l t h i c k n e s s of approximately 425 m. These rocks g e n e r a l l y form massive, competent outcrops and are not a f f e c t e d by weathering to the same degree as the l e s s r e s i s t a n t p y r o c l a s t i c u n i t s . Flows are medium-grained, p o r p h y r i t i c , and where hematite occurs in great abundance, they take on a d i s t i n c t i v e orange hue. P y r i t e and magnetite are p e r v a s i v e l y d i s t r i b u t e d throughout t h i s u n i t , the l a t t e r imparting a c h a r a c t e r i s t i c magnetism to the rock. Although the c o n t a c t of t h i s u n i t and the u n d e r l y i n g b r e c c i a ( u n i t 7 ) i s obscured by t a l u s , many of the lower most outcrops of a n d e s i t e c o n t a i n rounded x e n o l i t h s of pumiceous m a t e r i a l up to 5 cm a c r o s s , s i m i l a r to the m a t e r i a l found i n the b r e c c i a below. G e n e r a l l y outcrops are massive and s t r u c t u r e l e s s , although flow banding i s o c c a s i o n a l l y r e c o g n i z a b l e on weathered s u r f a c e s ( P l a t e 3-2). Numerous carbonate and quartz v e i n s from 0.1 to 1.0 cm t h i c k have developed along f r a c t u r e s w i t h i n these flows. Contacts between s u c c e s s i v e flows are d i f f i c u l t to d i s t i n g u i s h . 18 PLATE 3-1: Pumice b r e c c i a composed o f a n d e s i t e and pumice c l a s t s up t o 20 cm a c r o s s . Width o f photograph i s a p p r o x i m a t e l y 1 metre. PLATE 3-2: Flow banding i n h o r n b l e n d e a n d e s i t e . R h y o l i t e dyke i n t r u d e s a n d e s i t e a t bottom o f photo. Width o f photograph i s a p p r o x i m a t e l y 5 m e t r e s . 19 Andesite flows have o c c a s i o n a l l y been s i l i c i f i e d by hydrothermal f l u i d s . S i l c i f i e d flows ( u n i t 8a) have a sporadic d i s t r i b u t i o n and are g e n e r a l l y l e s s than 1 m t h i c k . The Mt. Graves gold and s i l v e r p r ospect, at 1800 m e l e v a t i o n on the northeast f l a n k of Mt. Graves, i s an e x c e p t i o n ( P l a t e 3-3). Here, b r e c c i a t e d and s i l i c i f i e d a n d e s i t e flows reach a t h i c k n e s s of 35 m (Chapter 5.2). S i l i c i c a l t e r a t i o n i s d e s c r i b e d i n d e t a i l l a t e r i n t h i s chapter. Unit 9 A t h i n , d i s c o n t i n u o u s u n i t of v o l c a n i c greywacke ( u n i t 9) crops out at the 2000 m l e v e l of Mt. Graves ( P l a t e I ) . T h i s r e c e s s i v e l y - w e a t h e r e d , maroon to brown e p i c l a s t i c bed ranges i n t h i c k n e s s from 1 to 10 m and i s l e n t i c u l a r . Composed of rounded a n d e s i t e c l a s t s , set i n a d i r t y , p o o r l y s o r t e d matrix^ t h i s rock type o c c a s i o n a l l y i s interbedded with f i n e l y laminated c a l c a r e o u s muds. Unit 10 A pyroxene a n d e s i t e flow ( u n i t 10) i s the uppermost u n i t of the Hazelton Group i n the study-area. I t i s approximately 320 m t h i c k and as a r e s u l t of the o x i d a t i o n of magnetite to hematite has a r e d d i s h maroon c o l o u r . T h i s u n i t forms massive blocky outcrops and i s h i g h l y r e s i s t a n t to weathering ( P l a t e 3-4). Rounded p o r p h y r i t i c - p l a g i o c l a s e - b e a r i n g x e n o l i t h s up to 5 cm i n diameter occur i n the lower p a r t of t h i s flow, the source of the x e n o l i t h s probably i s the u n d e r l y i n g hornblende 20 PLATE 3-3: A p o r t i o n o f t h e Mt. Graves main s i l i c i f i e d zone showing abundant j a r o s i t e , l i m o n i t e and manganese o x i d e on weathered s u r f a c e . Red p a i n t o u t l i n e s p a n e l s f o r d e t a i l e d c h i p s a m p l i n g . Width o f photograph i s a p p r o x i m a t e l y 15 metres. 21 PLATE 3-4: Pyroxene a n d e s i t e f l o w f o r m i n g prominent r i d g e on the n o r t h - w e s t f l a n k o f Mt. Graves. Ridge i s r o u g h l y 0.4 km i n l e n g t h . PLATE 3-5: S a u s s u r i t i z a t i o n o f p l a g i o c l a s e p h e n o c r y s t s i n hornblende a n d e s i t e . Note t r a c h y t i c a l i g n m e n t o f p l a g i o c l a s e c r y s t a l s . Width o f photomicrograph i s 3.2 mm. 22 a n d e s i t e s . B e c a u s e of t h e g e n e r a l l y m a s s i v e n a t u r e of t h i s u n i t i t i s d i f f i c u l t t o d i s t i n g u i s h i n d i v i d u a l f l o w s ; a l t h o u g h o c c a s i o n a l l y , d e g r e e of v e s i c u l a t i o n c an be u s e d t o l o c a t e f l o w c o n t a c t s . P e t r o l o g y The f o l l o w i n g p e t r o g r a p h i c d e s c r i p t i o n s of t h e H a z e l t o n G roup v o l c a n i c s a r e b a s e d on t h e s t u d y o f 42 t h i n s e c t i o n s . T e r m i n o l o g y u s e d t o d e s c r i b e w e l d i n g and c r y s t a l l i z a t i o n t e x t u r e s of p y r o c l a s t i c r o c k s i s c o n s i s t e n t w i t h t h e n o m e n c l a t u r e o f Lambert ( 1 9 7 4 ) . U n i t 7 Non- t o p a r t i a l l y - w e l d e d a n d e s i t e pumice b r e c c i a s a r e composed of 25 p e r c e n t a n d e s i t e l a p i l l i and 35 p e r c e n t d e v i t r i f i e d pumice c l a s t s s e t i n a v i t r o c l a s t i c groundmass of pumice f r a g m e n t s , g l a s s s h a r d s and b r o k e n p l a g i o c l a s e , b i o t i t e , h o r n b l e n d e and m a g n e t i t e c r y s t a l s . A n d e s i t e l a p i l l i , r o u n d e d d u r i n g f l o w , r a n g e i n s i z e from 3 mm t o 8 cm and a r e composed of 60 p e r c e n t e u h e d r a l p l a g i o c l a s e and h o r n b l e n d e p h e n o c r y s t s , s e t i n an u n o r i e n t e d groundmass of 0.1 mm p l a g i o c l a s e n e e d l e s and a n h e d r a l m a g n e t i t e g r a i n s . E u h e d r a l p l a g i o c l a s e g r a i n s a r e unzoned and have i n c l u s i o n s of m a g n e t i t e and h e m a t i t e . P l a g i o c l a s e c r y s t a l s show t h e e f f e c t s o f s a u s s u r i t i z a t i o n a s i n d i c a t e d by i r r e g u l a r c l o t s o f c a r b o n a t e , e p i d o t e and s e r i c i t e t h a t r e p l a c e most p h e n o c r y s t s , and by a l b i t i c p l a g i o g l a s e (AnO t o A n 5 ) . A l l e u h e d r a l t o a n h e d r a l h o r n b l e n d e s show a l t e r a t i o n 23 to e pidote and i n v a r i b l y have magnetite rims, that may have developed as a r e s u l t of o x i d a t i o n during or subsequent to e r u p t i o n . Groundmass p l a g i o c l a s e c r y s t a l s are a l s o s a u s s u r i t i z e d and s t a i n e d by h e m a t i t i c dust. Pumice c l a s t s are composed of 60 percent d e v i t r i f i e d g l a s s , 20 percent broken p l a g i o c l a s e phenocrysts and minor b i o t i t e and magnetite. A l l pumice shards show medium gra n u l a r d e v i t r i f i c a t i o n and have a c o l l a p s e d , n o n - v e s i c u l a r nature. As w e l l , many show d e v i t r i f i c a t i o n to s p h e r u l i t e s of c h l o r i t e . Length to width r a t i o s of pumice fragments range from 1.5:1 to 5.5:1 and average 2.5:1. A low degree of welding i s i n d i c a t e d by the absence of fiamme and of a w e l l developed e u t a x i t i c f a b r i c . Broken p l a g i o c l a s e phenocrysts are s i m i l a r to the p l a g i o c l a s e seen i n the a n d e s i t e l a p i l l i . They are c h a r a c t e r i s t i c a l l y 0.5 to 2.5 mm long, unzoned, a l b i t i c and s t r o n g l y s a u s s u r i t i z e d . Some show a l b i t e twinning but g e n e r a l l y twinning i s destroyed by replacement with carbonate and e p i d o t e . B i o t i t e phenocrysts average 0.8 mm i n l e n g t h and are g e n e r a l l y r e p l a c e d by aggregates of 0.05 mm epidote g r a i n s . Groundmass t e x t u r e s and mineralogy are i d e n t i c a l with those of the pumice c l a s t s , with a few e x c e p t i o n s . In the groundmass, pumice fragments are smaller (0.1 to 0.5 cm) and show a g r e a t e r degree of welding with l e n g t h to width r a t i o s a veraging 4:1. Shards of d e v i t r i f i e d g l a s s tend to be more abundant than pumice fragments; a p o o r l y developed e u t a x i t i c f a b r i c i s a l s o v i s i b l e . 24 Unit 8 Hornblende a n d e s i t e flows of u n i t 8 have p o r p h y r i t i c t e x t u r e s with phenocrysts of p l a g i o c l a s e , hornblende and magnetite comprising 30 to 45 percent of the mode. The groundmass a l s o c o n t a i n s f i n e g r a i n e d l a t h s of p l a g i o c l a s e and hornblende as w e l l as magnetite, hematite and minor d e v i t r i f i e d v o l c a n i c g l a s s . P l a g i o c l a s e phenocrysts comprising 19 to 30 percent of the mode, range i n l e n g t h from 0.5 to 3 mm, and are g e n e r a l l y euhedral, although many have broken f a c e s . C h l o r i t e r e p l a c e s most p l a g i o c l a s e c r y s t a l s e i t h e r as wormy intergrowths or along d i s c r e t e planes, mimicking o r i g i n a l c o m p o s i t i o n a l zoning. P l a g i o c l a s e i s r e p l a c e d with v a r i a b l e i n t e n s i t y , that r e f l e c t s c o m p o s i t i o n a l zoning, by s e r i c i t e and/or i l l i t e , carbonate and epidote ( P l a t e 3-5). No u n a l t e r e d zoned c r y s t a l s remain, making i t d i f f i c u l t to d i s t i n g u i s h the type of zoning i n the p l a g i o c l a s e . P l a g i o c l a s e d e t e r m i n a t i o n s are of poor q u a l i t y as a r e s u l t of e x t e n s i v e a l t e r a t i o n , but give a n o r t h i t e contents ranging from AnO to An35. Most phenocrysts have negative r e l i e f i n d i c a t i n g an a l b i t i c composition. Euhedral to anhedral hornblende phenocrysts or pseudomorphs of c h l o r i t e a f t e r hornblende, comprise 5 to 12 percent of the mode and g e n e r a l l y c o n t a i n i n c l u s i o n s of magnetite and a p a t i t e . They range i n s i z e from 0.5 to 1.0 mm and many are a l t e r e d to c h l o r i t e with i r o n oxide rims. P r e h n i t e pseudomorphs hornblende as w e l l as c h l o r i t e , and forms minute r a d i a t i n g aggregates r e p l a c i n g e n t i r e g r a i n s 25 ( P l a t e 3 - 6 ) . E u h e d r a l t o a n h e d r a l m a g n e t i t e p h e n o c r y s t s range i n s i z e f r o m 0.05 t o 1.5 mm and form 1 t o 10 p e r c e n t of t h e r o c k . They g e n e r a l l y have an o c t a h e d r a l o u t l i n e , a l t h o u g h where formed as an a l t e r a t i o n m i n e r a l , f i n e , a n h e d r a l g r a i n s a r e most common. E u h e d r a l p y r i t e p h e n o c r y s t s a l s o o c c u r but a r e l e s s abundant t h a n m a g n e t i t e . The groundmass i s composed o f e q u i g r a n u l a r p l a g i o c l a s e , c h l o r i t e and m a g n e t i t e p h e n o c r y s t s . A l i g n e d p l a g i o c l a s e l a t h s a r e c l o u d e d by f i n e h e m a t i t i c d u s t and have a l t e r a t i o n p a t t e r n s s i m i l a r t o t h o s e o f p l a g i o c l a s e p h e n o c r y s t s . V e s i c l e s up t o 5 mm i n d i a m e t e r a r e f i l l e d by c a r b o n a t e and c h l o r i t e , and c o m p r i s e l e s s t h a n 1 p e r c e n t of t h e mode. S i l i c i f i e d a n d e s i t e s ( u n i t 8a) commonly c o n t a i n up t o 85 p e r c e n t q u a r t z p o r p h y r o b l a s t s , b o t h as d i s c r e t e g r a i n s and as m i c r o c r y s t a l l i n e masses. P l a g i o c l a s e p h e n o c r y s t s a r e g e n e r a l l y b r o k e n and a r e pseudomorphed by q u a r t z o r c h l o r i t e ( P l a t e 3 - 7 ) . S i 1 i c i f i c a t i o n o f f l o w s i s d i s c u s s e d l a t e r i n t h i s c h a p t e r . U n i t 9 V o l c a n i c g r e y w a c k e s o f u n i t 9 show a s i m i l a r a l t e r a t i o n m i n e r a l o g y as t h e h o r n b l e n d e a n d e s i t e f l o w s . V o l c a n i c c l a s t s commonly c o n t a i n c h l o r i t i z e d p l a g i o c l a s e , h o r n b l e n d e , c a r b o n a t e and m i n o r m a g n e t i t e , and a b u n d a n t h e m a t i t e c l o u d s most of t h e c o n s t i t u e n t p h e n o c r y s t s . PLATE 3-6: Prehnite pseudomorphing hornblende phenocryst i n andesite. Width of photomicrograph i s 1.8 mm. PLATE 3-7: Quartz pseudomorphing plagioclase phenocryst i n s i l i c i f i e d andesite flow. Width of photomicrograph i s 1.8 mm. 27 U n i t 10 P y r o x e n e a n d e s i t e f l o w s a r e s i m i l a r i n t e x t u r e and m i n e r a l o g y t o h o r n b l e n d e a n d e s i t e s but p h e n o c r y s t s o f p y r o x e n e o c c u r i n s t e a d of h o r n b l e n d e g r a i n s . B r o k e n e u h e d r a l p y r o x e n e g r a i n s r a n g e i n s i z e f r o m 0.1 t o 2.5 mm and a r e u n i f o r m i l y pseudomorphed by c h l o r i t e and rimmed by i r o n o x i d e s . O c c a s i o n a l l y , e u h e d r a l i r o n o x i d e g r a i n s d e l i n e a t e c r y s t a l g r o w t h z o n e s w i t h i n p y r o x e n e c r y s t a l s p e r h a p s i n d i c a t i n g s u c c e s s i v e p e r i o d s of o x i d i z i n g c o n d i t i o n s d u r i n g d e v e l o p m e n t , o r p o s s i b l y p r i m a r y Fe/Mg z o n i n g w h i c h has been l a t e r o x i d i z e d ( P l a t e 3 - 8 ) . Many of t h e r o u n d e d l i t h i c f r a g m e n t s of p o r p h y r i t i c a n d e s i t e c o n t a i n amygdules of p r e h n i t e , c a r b o n a t e and c h l o r i t e up t o 2.5 mm i n d i a m e t e r ( P l a t e 3 - 9 ) . O t h e r m i n e r a l o g i c a l and t e x t u r a l f e a t u r e s a r e i d e n t i c a l t o t h o s e of t h e h o r n b l e n d e a n d e s i t e s and t h e r e f o r e a r e n o t d i s c u s s e d f u r t h e r . A l t e r a t i o n H y d r o t h e r m a l a l t e r a t i o n o f t h e H a z e l t o n G r o u p i s w i d e s p r e a d , b e i n g b o t h p e r v a s i v e and f r a c t u r e - c o n t r o l l e d . P r o p y l i t i c a l t e r a t i o n i s p e r v a s i v e t h r o u g h o u t a l l m a j o r u n i t s and i s d i s t i n g u i s h e d by c h l o r i t i z a t i o n o f m a f i c g r a i n s , s a u s s u r i t i z a t i o n o f p l a g i o c l a s e p h e n o c r y s t s , a s w e l l as f o r m a t i o n of e p i d o t e , c a r b o n a t e , s e r i c i t e a n d / o r i l l i t e , and p y r i t e i n t h e groundmass. F r a c t u r e - c o n t r o l l e d and p e r v a s i v e s i l i c i f i c a t i o n of a n d e s i t e f l o w s i s a r e l a t i v e l y common a l t e r a t i o n s t y l e 28 PLATE 3-8: I r o n o x i d e g r a i n s d e l i n e a t e growth zones i n c h l o r i t i z e d pyroxene p h e n o c r y s t . Groundmass i s c h i e f l y composed o f c h l o r i t i z e d p l a g i o c l a s e m i c r o l i t e s . Width o f p h o t o m i c r o g r a p h i s 0.9 mm. PLATE 3-9: L i t h i c fragment o f p o r p h y r i t i c a n d e s i t e c o n t a i n i n g amygdules o f p r e h n i t e , c a r b o n a t e and c h l o r i t e . Width o f photo-m i c r o g r a p h i s 3.2 mm. 29 w i t h i n t h e r e g i o n . P h e n o c r y s t s a r e s e l e c t i v e l y r e p l a c e d and pseudomorphed by f i n e g r a i n e d q u a r t z w i t h i n t h e s e z o n e s . As w e l l , m i c r o - v e i n l e t s of q u a r t z and c a r b o n a t e become more abundant as d e g r e e o f s i l i c i f i c a t i o n i n c r e a s e s . W i t h i n w h o l l y s i l i c i f i e d and b r e c c i a t e d r e g i o n s , q u a r t z r e p l a c e s a l l g r a i n s and o r i g i n a l t e x t u r e s w i t h i n t h e f l o w a r e c o m p l e t e l y d e s t r o y e d . L a t e s t a g e f r a c t u r e c o n t r o l l e d h y d r o t h e r m a l a l t e r a t i o n i s r e c o g n i z e d by an abundance of c a r b o n a t e , l a u m o n t i t e and p r e h n i t e v e i n l e t s up t o 0.5 cm i n w i d t h . T h i s form of a l t e r a t i o n o v e r p r i n t s e a r l i e r p r o p y l i t i c and s i l i c i c s t y l e s , and i s c o n f i n e d t o z o n e s o f i n t e n s e l y f r a c t u r e d r o c k . In p y r o c l a s t i c u n i t s , p y r i t e and m a g n e t i t e a r e g e n e r a l l y o x i d i z e d t o l i m o n i t e and h e m a t i t e r e s p e c t i v e l y ; t h i s may i n d i c a t e t h e p r e s e n c e o f o x i d i z e d p o r e w a t e r s d u r i n g l o w - g r a d e metamorphism. S t r u c t u r e H a z e l t o n Group v o l c a n i c s c r o p out on Mt. G r a v e s and form one l i m b of a n o r t h w e s t - t r e n d i n g a n t i c l i n e t h a t i s b r e a c h e d i n i t s c o r e by q u a r t z m o n z o n i t e i n t r u s i o n s ( P l a t e I and P l a t e I I I ) . In c o n t r a s t t o t h e g e n t l e s o u t h - w e s t e r l y d i p s o f t h e Toodoggone v o l c a n i c s , H a z e l t o n r o c k s d i p s t e e p l y t o t h e n o r t h e a s t a t a n g l e s between 55 and 75 d e g r e e s . H a z e l t o n r o c k s a r e i n f a u l t c o n t a c t w i t h Toodoggone v o l c a n i c s , a l t h o u g h t h e y may u n c o n f o r m a b l y o v e r l i e t h e Toodoggone r o c k s i n o t h e r d i s t r i c t s ( P a n t e l e y e v , 1982). Numerous s t e e p l y d i p p i n g mormal f a u l t s c r o s s t h e r e g i o n and 30 form most of t h e b o u n d a r i e s between l i t h o l o g i c u n i t s . Age and C o r r e l a t i o n The age o f t h e H a z e l t o n Group i s b a s e d on m a r i n e f a u n a s c o l l e c t e d from a r e a s n e a r S m i t h e r s and H a z e l t o n , as w e l l as from t h e M c C o n n e l l C r e e k m a p-sheet. In t h e s t u d y - a r e a , H a z e l t o n r o c k s a p p e a r t o c o r r e l a t e on t h e b a s i s of l i t h o l o g y w i t h t h e Howison S u b f a c i e s of t h e T e l k w a F o r m a t i o n d e s c r i b e d by T i p p e r and R i c h a r d s ( 1 9 7 6 ) . On t h e b a s i s of t h i s c o r r e l a t i o n , H a z e l t o n r o c k s i n t h e r e g i o n a r e L a t e S i n e m u r i a n i n age. T i p p e r and R i c h a r d s (1976) s t a t e t h a t H a z e l t o n Group r o c k s span E a r l y J u r a s s i c ( S i n e m u r i a n ) t o M i d d l e J u r a s s i c (Lower C a l l o v i a n ) t i m e . 3 . 3 Toodoggone V o l c a n i c s V o l c a n i c and e p i c l a s t i c r o c k s of t h e Toodoggone v o l c a n i c s have been d i v i d e d i n t o e l e v e n map u n i t s on t h e b a s i s o f m i n e r a l o g i c a l and t e x t u r a l c h a r a c t e r i s t i c s ( F i g u r e " 3-1, P l a t e I ) . T u f f s and v o l c a n i c s f l o w s form t h e m a j o r i t y of t h e l i t h o l o g i c a l u n i t s ; e a c h h a v i n g a p p r o x i m a t e l y t h e same a e r i a l e x t e n t w i t h i n t h e s t u d y - a r e a . The n o m e c l a t u r e u s e d i n t h e f o l l o w i n g f i e l d o b s e r v a t i o n s i s c o n s i s t a n t w i t h t h a t o f S m i t h ( 1 9 6 0 a ) , Ross and S m i t h ( 1 9 6 1 ) , F i s h e r (1961, 1966), P a r s o n s (1966) and W r i g h t e t a l . , ( 1 9 8 0 ) . F i g u r e 3-1 shows a d i a g r a m a t i c c o m p o s i t e s t r a t i g r a p h i c s e c t i o n o f t h e Toodoggone R i v e r a r e a . 31 G e n e r a l G e o l o g y U n i t 11 H o r n b l e n d e a n d e s i t e f l o w s f o r m t h e o l d e s t e x t r u s i v e u n i t w i t h i n t h e Toodoggone R i v e r a r e a . T y p i c a l l y t h e y a r e maroon t o g r e y - brown and f o r m m a s s i v e b l o c k y o u t c r o p s . Of l i m i t e d d i s t r i b u t i o n w i t h i n t h e a r e a , t h e b e s t e x p o s u r e c r o p s o u t a t between 1800 and 2000 m a l o n g t h e e a s t e r n m a r g i n o f t h e map-area ( P l a t e I ) . H i g h l y v e s i c u l a r and f l o w banded, t h i s u n i t has a minimum t h i c k n e s s o f 55 m. Flow b a n d i n g i s e a s i e s t r e c o g n i z e d on w e a t h e r e d s u r f a c e s , where i t c a n be d i s t i n g u i s h e d as a l t e r n a t i n g d a r k and l i g h t bands of h e m a t i t e - r i c h and h e m a t i t e - p o o r l a y e r s . T h i s u n i t i s medium g r a i n e d w i t h p l a g i o c l a s e , h o r n b l e n d e and m i n o r m a g n e t i t e b e i n g t h e most e a s i l y r e c o g n i z e d p h e n o c r y s t s i n hand s p e c i m e n . Most o f t h e m a g n e t i t e has been o x i d i z e d t o h e m a t i t e , d i s t i n g u i s h i n g t h i s f l o w f r o m t h e m a g n e t i c a n d e s i t e u n i t s t h a t a r e w i d e s p r e a d t h r o u g h o u t t h e r e g i o n . U n i t 12 A d i s c o n t i n u o u s 20 t o 40 m t h i c k h o r n b l e n d e a n d e s i t e f l o w o v e r l i e s t h e v e s i c u l a r f l o w of u n i t 11. I t t o o i s o f l i m i t e d a e r i a l e x t e n t ( P l a t e I ) . T h i s f l o w i s d a r k g r e y , and forms p r o m i n e n t o u t c r o p s . E x t e n s i v e e p i d o t i z a t i o n of p l a g i o c l a s e p h e n o c r y s t s i m p a r t s a l i g h t g r e e n d i s c o l o u r a t i o n t o t h e r o c k . An abundance of x e n o l i t h s , d i s t i n g u i s h e s t h i s f l o w f r o m t h e p r e v i o u s one ( u n i t 11). S u b r o u n d e d t o s u b a n g u l a r h o r n b l e n d e , p l a g i o c l a s e a n d e s i t e p o r p h y r y x e n o l i t h s c o m p r i s e up t o 40 p e r c e n t o f t h i s u n i t , and 32 S U S T U T K/T (24) H A Z E L T O N pyroxene andesite flow (10) volcanic greywacke -(9) s i l i c i f i e d andesite -hornblende a n d e s i t e -flow (8) pumice breccia — T O O D O G G O N E volcanic greywacke and shale (21) • v i t r i c - c r y sta I ash tuff (20) v i t r i c ash to l a p i l l i tuff (19) > O H rn co v i t r i c — l i t h i c ash tuff ( 1 8 ) = v i t r i c ash to l a p i l l i tuff (17) a r g i l l i z e d andesite( i4t>) s i l i c i f i e d andesite (14a) ' - t r a c h y t e flow(ie) > sil i c i f i e d trachyte *~ (16a) O m volcanic g reywacke^ hornblende OS) — a ndesite f low (1 4) H -agglomerate fTI and b r e c c i a (1 3) CO - hornblende andesite f I o w (1 2) hornblende andesite fIow(1 1 ) — T A K L A (2.3,4.5) FIGURE 3-1: Diagramatic composite s t r a t i g r a p h i c s e c t i o n s o f the Toodoggone R i v e r area. No s p a t i a l r e f e r e n c e i s i m p l i e d . 33 i n c r e a s e i n s i z e and number as s t r a t i g r a p h i c a l l y l o w e r z o n e s o f t h e f l o w a r e examined. U n i t 13 An e x t r e m e l y h e t e r o g e n e o u s u n i t c o m p r i s i n g a g g l o m e r a t i c a c c u m u l a t i o n s of bomb s i z e d p y r o c l a s t i c m a t e r i a l , pumice b r e c c i a s and minor a s h - f l o w t u f f s and e p i c l a s t i c s e d i m e n t s o v e r l i e s t h e a n d e s i t e f l o w s of u n i t 12. G r e y - g r e e n a g g l o m e r a t e s of u n i t 13 a r e composed of s e m i - s p h e r i c a l v o l c a n i c bombs r a n g i n g i n s i z e f r o m 1 cm t o o v e r 2 m. C l a s t s a r e g e n e r a l l y f a i r l y w e l l s o r t e d and t e n d t o c o a r s e n down s e c t i o n , as w e l l as l a t e r a l l y . T h i s u n i t r e a c h e s a maximum t h i c k n e s s o f 100 m, a l t h o u g h t h i c k n e s s e s of between 60 and 80 m a r e more common. F r e q u e n t l y r e w o r k e d l a y e r s of a s h and f i n e s e d i m e n t up t o 1.5 m t h i c k o c c u r a s l e n s e s w i t h i n t h e a g g l o m e r a t i c z o n e s ( P l a t e 3 -10). Pumice b r e c c i a s and t h i n a s h - f l o w t u f f s a l s o c o m p r i s e t h i s u n i t , b u t a r e s u b o r d i n a t e t o t h e v o l c a n i c bomb d e p o s i t s . A s h - f l o w l a y e r s r e a c h a maximum t h i c k n e s s o f 10 m e t r e s and have a v e r y l i m i t e d l a t e r a l e x t e n t . Pumice b r e c c i a s , s i m i l a r t o t h o s e f o u n d i n t h e H a z e l t o n v o l c a n i c s a r e maroon i n c o l o u r , and o c c u r a s l e n s - l i k e pods w i t h i n t h e a g g l o m e r a t e s . T h i s u n i t p r o b a b l y o c c u r s c l o s e t o a v o l c a n i c v e n t , when b r e c c i a b l o c k s a r e a n g u l a r i n n a t u r e and when t h e s i z e o f t h e a g g l o m e r a t i c bombs e x c e e d 1 m i n d i a m e t e r . B o t h t h e a g g l o m e r a t e and pumice b r e c c i a u n i t s r e c e s s i v e l y w e a t h e r , f o r m i n g o d d l y shaped p i n a c l e s and domes ( P l a t e PLATE 3-10: Agglomerate w i t h l a y e r s o f ash and f i n e sediment. C l a s t s a r e up t o 25 cm a c r o s s . 35 PLATE 3-11; Agglomerate and pumice b r e c c i a showing odd w e a t h e r i n g p a t t e r n . A n d e s i t e f l o w s o v e r l i e t h e agglomerates i n t h e upper p a r t o f the photograph. B l o c k s i n t h e f o r e g r o u n d a r e a p p r o x i m a t e l y 0.7 5 metres a c r o s s . 36 U n i t 14 One of the most voluminous u n i t s w i t h i n the Toodoggone Ri v e r area i s a 180 to 280 m t h i c k hornblende a n d e s i t e flow that o v e r l i e s u n i t 13. Grey-green to dark green where f r e s h , t h i s u n i t i s medium gr a i n e d and p o r p h y r i t i c with phenocrysts of p l a g i o c l a s e , hornblende and magnetite being e a s i l y r e c o g n i z a b l e i n hand specimen. T h i s u n i t i s e r o s i o n r e s i s t a n t , and c h a r a c t e r i s t i c a l l y green because of e p i d o t i z e d p l a g i o c l a s e phenocrysts ( P l a t e 3-12). Outcrops are g e n e r a l l y s t r u c t u r e l e s s , although flow banding and v e s i c u l a r zones are n o t i c a b l e on weathered s u r f a c e s ( P l a t e 3-13). A l s o i n c l u d e d w i t h i n t h i s u n i t are l o c a l i z e d zones of a s h - f a l l t u f f . P y r o c l a s t i c l e nses and beds do-not exceed 20 m i n t h i c k n e s s , with the g r e a t e s t ash accumulation o c c u r i n g in the v i c i n i t y of the S i l v e r p o n d property ( P l a t e I ) . Both s i l i c i f i e d a n d e s i t e flows (Unit 14a) and a r g i l l i c a l l y a l t e r e d flows and t u f f s (Unit 14b) occur i n the region surrounding the S i l v e r p o n d p r o p e r t y , and are d i s c u s s e d l a t e r i n t h i s chapter. Unit 15 The t h i n , d i s c o n t i n u o u s v o l c a n i c greywacke of u n i t 15 i s s i m i l a r to the e p i c l a s t i c v o l c a n i c s of the Hazelton Group (Chapter 3.2) and o v e r l i e s the a n d e s i t e flows of u n i t 14. T h i s u n i t i s unsorted and unbedded and r a r e l y exceeds 35 m i n t h i c k n e s s . F a u l t i n g d u r i n g the accumulation of u n i t 15 produced scarps, which acted as t r a p s f o r the sediments, 37 PLATE 3-12: Ep i d o t i z e d and hematite s t a i n e d p l a g i o c l a s e phenocrysts i n andesite. Ground-mass i s composed of c h l o r i t i z e d p l a g i o c l a s e and hornblende g r a i n s . Width of photograph i s roughly 5 cm. PLATE 3-13: Flow banding on weathered surface of a hornblende andesite flow. Width of photograph i s approximately 1 metre. 38 p r o d u c e d t h r o u g h w e a t h e r i n g o f t h e v o l c a n i c s . U n i t 16 T r a c h y t e f l o w s of u n i t 16 have a l i m i t e d d i s t r i b u t i o n w i t h i n t h e map-area. The o n l y e x p o s u r e i s i n t h e Moosehorn C r e e k c a n y o n ( P l a t e I ) . Here t h e f l o w s r e a c h a maximum t h i c k n e s s o f 225 ni, and form n e a r l y v e r t i c a l c l i f f s ( P l a t e 3-14). Most of t h e f l o w s a r e salmon p i n k and c o n t a i n a b undant h e m a t i t i z e d s a n i d i n e and p l a g i o c l a s e p h e n o c r y s t s . H y d r o t h e r m a l f l u i d s have b r e c c i a t e d and s i l i c i f i e d much o f th e e x p o s e d f l o w of U n i t 16a; t h e Moosehorn Amethyst B r e c c i a p r o s p e c t o c c u r s w i t h i n t h i s u n i t ( F i g u r e 3-2 and C h a p t e r 5 . 2 ) . G e n e r a l l y u n i t 16 i s n o n - v e s i c u l a r , m a s s i v e and q u i t e b r i t t l e , s p l i n t e r i n g when hammered. B o t h l a t e r a l l y and v e r t i c a l l y i t t e n d s t o i n t e r f i n g e r w i t h g r e y - g r e e n a n d e s i t e f l o w s o f u n i t 14. O c c a s i o n a l l y r o u n d e d t o a n g u l a r x e n o l i t h s of a n d e s i t e o c c u r w i t h i n t h e t r a c h y t e s . In t h e Moosehorn C r e e k c a n y o n c o n t a c t s between s u c c e s s i v e f l o w s c a n be d e f i n e d by v a r i a t i o n s i n h e m a t i t i c s t a i n i n g , t h a t i s due t o th e o x i d a t i o n of m a g n e t i t e t o h e m a t i t e i n t h e u n d e r l y i n g f l o w u n i t s . U n i t 17 M o d e r a t e l y - w e l d e d v i t r i c a s h t o l a p i l l i t u f f of u n i t 17 c r o p s o u t a t 2000 m e l e v a t i o n , n e a r t h e c e n t r e o f t h e map-area ( P l a t e I ) . T h i s u n i t r e p r e s e n t s a change t o a more e x p l o s i v e , d a c i t i c form of v o l c a n i s m . U n i t 17 i s g r e y - g r e e n PLATE 3-14: T r a c h y t e f l o w s f o r m i n g prominent c l i f f s i n the Moosehorn Creek canyon. Note c o n t a c t between upper and lower f l o w a t t h e c e n t e r o f the photo. C l i f f s a r e r o u g h l y 4 5 metres i n h e i g h t . PLATE 3-15: View l o o k i n g e a s t from t h e Lawyers d e p o s i t showing c l i f f s o f g e n t l y d i p p i n g v i t r i c a sh t o l a p i l l i t u f f . Width o f photograph i s a p p r o x i m a t e l y 1.5 km. 40 r500 -400 -300 co ui cc UJ •200 \ -= -100 *-0 HORNBLENDE ANDESITE FLOW 14 VOLCANIC G R E Y W A C K E 15 Moosehorn Amethyst B r e c c i a Zone >TRACHYTE FLOW 16 T r a c h y t e f l o w i s b r e c c i a t e d and s i l i c i f i e d , w i t h c h a l c e d o n i c o r a m e t h y s t i n e q u a r t z b e i n g most common. Abundant h e m a t i t e and wad s t a i n i n g o c c u r s on f r a c t u r e s u r f a c e s . HORNBLENDE ANDESITE FLOW 14 VOLCANIC G R E Y W A C K E 15 FIGURE 3-2: S t r a t i g r a p h i c s e c t i o n o f the Toodoggone v o l c a n i c s i n Moosehorn Creek canyon. ( P l a t e I i n d i c a t e s t h e l o c a t i o n o f s e c t i o n s ) 41 t o g r e y - b r o w n and i s composed o f b r o k e n pumice f r a g m e n t s w i t h a b u n d a n t c r y s t a l s o f h e m a t i t i z e d p l a g i o c l a s e , q u a r t z and h o r n b l e n d e b e i n g e a s i l y v i s i b l e i n hand s p e c i m e n . Formed as a p y r o c l a s t i c f l o w , i t t e n d s t o w e a t h e r r e c e s s i v e l y and n e v e r a t t a i n s t h i c k n e s s e s of g r e a t e r t h a n 40 m. U n i t 18 V i t r i c - l i t h i c a s h t u f f s of u n i t 18 o v e r l i e t h e v i t r i c a s h t o l a p i l l i t u f f s of u n i t 17. U n i t 18 r o c k s a r e maroon, p o r o u s , h i g h l y w e a t h e r e d and c o n s i s t of s u b a n g u l a r a n d e s i t i c and g r a n i t i c c l a s t s , d e v i t r i f i e d pumice f r a g m e n t s and c r y s t a l s o f s a n i d i n e , p l a g i o c l a s e , h o r n b l e n d e and b i o t i t e . The a s h f l o w i t s e l f r a n g e s i n t h i c k n e s s from 75 t o 100 m, and i s b e s t e x p o s e d a t 1600 m e l e v a t i o n i n t h e n o r t h e a s t p a r t o f t h e s t u d y - a r e a ( P l a t e I ) . Un i t 19 D a c i t i c v i t r i c a s h t o l a p i l l i t u f f s o f u n i t 19 o v e r l i e t h e v i t r i c - l i t h i c t u f f s o f u n i t 18 w i t h w h i c h t h e y r e s e m b l e i n m o r p h o l o g y and c o m p o s i t i o n . However, t h e r o u n d e d c l a s t s of a n d e s i t e , abundant i n u n i t 18 a r e n o t i c a b l y a b s e n t . T h i s a s h - f l o w s h e e t of u n i t 19 c o m p r i s e s t h e most e x t e n s i v e and e a s i l y r e c o g n i z a b l e u n i t i n t h e Toodoggone R i v e r a r e a ; i t i s up t o 280 m t h i c k . The r o c k s a r e l i g h t t o d a r k g r e y on f r e s h s u r f a c e s , but d a r k brown v a r i e t i e s a l s o e x i s t where r o c k s a r e l e s s r e s i s t a n t and w e a t h e r e d . W e l l j o i n t e d s c a r p s c h a r a c t e r i z e t h i s f l o w and form most o f t h e r i d g e s i n t h e 42 c e n t r e of the map-area ( P l a t e 3-15). Compaction and welding i s v a r i a b l e throughout t h i s u n i t , ranging from low to moderate i n t e n s i t i e s . Moderately welded zones e x h i b i t a weak f o l i a t i o n r e s u l t i n g from the alignment of pumice fragments. X e n o l i t h s of g r a n i t i c m a t e r i a l , as we l l as some T a k l a c l a s t s r a r e l y exceed 5 cm i n diameter and comprise l e s s than 5 percent of the ash flow. U n i t 19 i s a massive, homogeneous ash flow, which probably acted as a s i n g l e c o o l i n g u n i t , because no d i f f e r e n t i a t i o n can be made between separate flows. L i t h o l o g i c a l l y s i m i l a r flows occur to the south of the study-area, and cover a minimum of 500 square km (Panteleyev, 1983). I t can t h e r e f o r e be c l a s s i f i e d as a major ash-flow u n i t by comparison with flows of the San Juan d i s t r i c t i n Colorado (Steven et a l . , 1976). Unit 20 D a c i t i c v i t r i c - c r y s t a l ash t u f f s of u n i t 20 are s i m i l a r to the u n d e r l y i n g l a p i l l i t u f f s of u n i t 19, although pumice fragments are much l e s s abundant i n the ash flows of u n i t 20. U n i t 20 tends to be grey-green and reaches a maximum t h i c k n e s s of 175 m (Fi g u r e 3-3). Compared to other p y r o c l a s t i c flows in the Toodoggone River r e g i o n , u n i t 20 tends to be f a r l e s s r e s i s t a n t to weathering, p o s s i b l y as a r e s u l t of the lower degree of welding that t h i s u n i t has undergone. G r a n i t i c c l a s t s , r a r e l y exceeding 4 cm i n diameter, comprise l e s s than 2 percent of t h i s ash flow. 4 3 r 7 0 0 _ 18m VOLCANIC GREYWACKE -600 - ^ 175m -500 VITRIC-CRYSTAL ASH TUFF 20 -400 100m co UJ CC I-UJ 2 •300 110m •200 o s 180m •100 VITRIC ASH TO LAPILLI TUFF 19 V i t r i c ash t o l a p i l l i t u f f i s h i g h l y f r a c t u r e d w i t h laumont-i t e , c a l c i t e and minor f l u o r i t e f i l l i n g l a t e s t a g e v e i n s . 90m VITRIC-LITHIC ASH TUFF 18 FIGURE 3-3: S t r a t i g r a p h i c s e c t i o n o f the Toodoggone v o l c a n i c s near t h e GWP 1 t o 10 g o l d and s i l v e r p r o s p e c t . ( P l a t e I i n d i c a t e s the l o c a t i o n o f s e c t i o n s ) 44 U n i t 21 V o l c a n i c greywacke and m i n o r s h a l e of u n i t 21 o v e r l i e t h e v i t r i c - c r y s t a l a s h t u f f s of u n i t 20. G e n e r a l l y t h e y a r e p o o r l y s o r t e d , s t r u c t u r e l e s s s e d i m e n t s t h a t r a n g e i n c o l o u r from g r e y t o b r o w n i s h - g r e e n t o b l a c k . They a r e c h i e f l y composed of sand s i z e d t u f f a c e o u s v o l c a n i c m a t e r i a l , as w e l l as m i n o r g r a n i t i c and d a c i t i c c l a s t s . Beds r a n g e i n t h i c k n e s s from a few c e n t i m e t r e s t o t e n s of m e t r e s . Reworked t u f f a c e o u s m a t e r i a l o c c a s i o n a l l y e x h i b i t s p o o r l y d e v e l o p e d b e d d i n g up t o 2 cm t h i c k , w i t h c y c l i c a l l y g r a d e d z o n e s r e a c h i n g up t o 50 cm. I n t e r b e d d e d w i t h t h e s e t u f f s a r e beds o f mudstone, s i l t s o n e and s h a l e t h a t f r e q u e n t l y d i s p l a y r a i n d r o p i m p r i n t s and l o a d s t r u c t u r e s . P e t r o l o g y The f o l l o w i n g p e t r o g r a p h i c d e s c r i p t i o n s o f t h e Toodoggone v o l c a n i c s a r e b a s e d on t h e s t u d y o f o v e r 100 t h i n s e c t i o n s . T e r m i n o l o g y u s e d t o d e s c r i b e w e l d i n g and c r y s t a l l i z a t i o n t e x t u r e s of p y r o c l a s t i c r o c k s i s c o n s i s t a n t w i t h t h e n o m e n c l a t u r e o f Lambert ( 1 9 7 4 ) . U n i t s 11, 12 and 14 H o r n b l e n d e a n d e s i t e f l o w s ( u n i t s 11, 12 and 14) t y p i c a l l y a r e p o r p h y r i t i c w i t h p h e n o c r y s t s o f p l a g i o c l a s e , h o r n b l e n d e and m i n o r b i o t i t e c o m p r i s i n g between 20 and 35 p e r c e n t of t h e r o c k s . A t r a c h y t i c groundmass i s composed of a c c i c u l a r l a t h s o f p l a g i o c l a s e , e u h e d r a l h o r n b l e n d e , as w e l l as m i n o r c h l o r i t e , e p i d o t e , m a g n e t i t e , h e m a t i t e , p y r i t e and 45 d e v i t r i f i e d v o l c a n i c g l a s s . The amount of modal h e m a t i t e i s v a r i a b l e between f l o w s , depending on the i n t e n s i t y of o x i d a t i o n , whereas o t h e r m i n e r a l o g i c a l and t e x t u r a l c h a r a c t e r i s t i c s seem t o be r e l a t i v e l y c o n s i s t a n t . P l a g i o c l a s e c r y s t a l s c o m prise a p p r o x i m a t e l y 65 t o 75 p e r c e n t of the p h e n o c r y s t s and range i n s i z e from 0.5 t o 2.5 mm. E u h e d r a l t o broken e u h e d r a l g r a i n s a r e o c c a s i o n a l l y r e p l a c e d by c h l o r i t e , which pseudomorphs o r i g i n a l c o m p o s i t i o n a l z o n i n g w i t h i n c r y s t a l s ( P l a t e 3-16). S a u s s u r i t i z a t i o n of p l a g i o c l a s e p h e n o c r y s t s i s a l s o v e r y common, w i t h e p i d o t e , s e r i c i t e and/or i l l i t e and c a r b o n a t e r e p l a c i n g the c o r e s of s e l e c t e d g r a i n s ( P l a t e 3-17). P h e n o c r y s t s are g e n e r a l l y a l b i t i c i n c o m p o s i t i o n , r a n g i n g from AnO t o An25. Most g r a i n s are c l o u d e d by abundant h e m a t i t e i n c l u s i o n s , p o s s i b l y i n d i c a t i v e of e r u p t i o n i n a s u b a e r i a l environment ( P l a t e 3-18). Hornblende p h e n o c r y s t s range i n l e n g t h from 0.25 t o 1.0 mm, and comprise 5 t o 15 p e r c e n t of the p h e n o c r y s t s . L i t t l e o r i g i n a l h ornblende remains, w i t h most c r y s t a l s b e i n g c o m p l e t e l y r e p l a c e d by e p i d o t e and i r o n o x i d e s . T y p i c a l l y , a r e l i c h o r n b lende o u t l i n e remains, w i t h f i n e g r a i n e d a g g r e g a t e s of e p i d o t e pseudomorphing h o r n b l e n d e c l e a v a g e . I r o n o x i d e s r i m most g r a i n s , i n d i c a t i n g o x i d a t i o n 'of hornblende p h e n o c r y s t s soon a f t e r e r u p t i o n . E u h e d r a l b i o t i t e p h e n o c r y s t s are much l e s s abundant than hornblende g r a i n s , and g e n e r a l l y show replacement by c h l o r i t e and i r o n o x i d e s a l o n g c l e a v a g e , w i t h l i t t l e or no o r i g i n a l b i o t i t e r e m a i n i n g ( P l a t e 3-19). 4 6 PLATE 3 - 1 6 : C h l o r i t e r e p l a c i n g p l a g i o c l a s e w i t h i n p a r t i c u l a r c o m p o s i t i o n a l zones i n ho r n b l e n d e a n d e s i t e . Width o f ph o t o m i c r o g r a p h i s 3 . 2 mm. PLATE 3 - 1 7 : E p i d o t e and s e r i c i t e r e p l a c i n g t h e c o r e o f p l a g i o c l a s e p h e n o c r y s t s i n a n d e s i t e . Note numerous secondary q u a r t z g r a i n s s u r r o u n d i n g a l t e r e d p l a g i o c l a s e c r y s t a l s . Width o f photomicrograph i s 1 . 8 mm. PLATE 3-18: P l a g i o c l a s e p h e n o c r y s t i n a n d e s i t e c l o u d e d w i t h abundant h e m a t i t e i n c l u s i o n s . S e r i c i t e and/or i l l i t e r e p l a c e s p l a g i o c l a s e a l o n g f r a c t u r e s . Width o f p h o t o m i c r o g r a p h i s 0.9 mm. PLATE 3-19: M a g n e t i t e r e p l a c i n g b i o t i t e i n a n d e s i t e . Groundmass i s composed o f s e r i c i t i z e d p l a g i o c l a s e , m a g n e t i t e and h e m a t i t e . Width o f ph o t o m i c r o g r a p h i s 3.2 mm. 48 M a g n e t i t e o c c u r s as a n h e d r a l p h e n o c r y s t s and as f i n e a g g r e g a t e s w i t h i n the groundmass. Hematite f r e q u e n t l y rims most p r i m a r y m a g n e t i t e g r a i n s and i s d i s p e r s e d throughout the groundmass c l o u d i n g a l l c o n s t i t u e n t p h e n o c r y s t s . P r i s m a t i c a p a t i t e c r y s t a l s o ccur as i n c l u s i o n s w i t h i n p l a g i o c l a s e and hornblende p h e n o c r y s t s and range i n s i z e from 0.05 t o 0.25 mm. S u c c e s s i v e a n d e s i t e f l o w s ( u n i t s 11 and 12) can be d i s t i n g u i s h e d by the g r e a t e r abundance of a n d e s i t i c and g r a n i t i c x e n o l i t h s i n u n i t 12. The a n d e s i t e f l o w s of u n i t 14 have a much g r e a t e r m a g n e t i t e c o n t e n t than the u n d e r l y i n g f l o w s of u n i t s 11 and 12. U n i t 13 Agglomerates and pumice b r e c c i a s have e s s e n t i a l l y the same m i n e r a l o g y as the a n d e s i t e f l o w s and p y r o c l a s t i c r o c k s of the H a z e l t o n v o l c a n i c s d e s c i b e d i n Chapter 3.2. V o l c a n i c bombs range up t o 2.0 metres i n diameter and i n t h i n s e c t i o n have i d e n t i c a l m i n e r a l o g i e s t o the hornblende a n d e s i t e f l o w s , u n i t s 11, 12 and 14. U n i t 15 V o l c a n i c greywackes of u n i t 15 have a l l the m i n e r a l o g i c a l and t e x t u r a l c h a r a c t e r i s t i c s of the e p i c l a s t i c r o c k s of the H a z e l t o n Group. U n i t 16 T r a c h y t e f l o w s c h a r a c t e r i s t i c a l l y a r e p o r p h y r i t i c w i t h 49 p h e n o c r y s t s of s a n i d i n e , p l a g i o c l a s e , b i o t i t e , h o r n b l e n d e and m i n o r m a g n e t i t e c o m p o s i n g between 15 and 40 p e r c e n t o f t h e r o c k . M a t r i c e s t y p i c a l l y c o n s i s t of f i n e g r a i n e d a g g r e g a t e s of p o t a s s i u m f e l d s p a r , m a g n e t i t e , p y r i t e , h e m a t i t e and v o l c a n i c g l a s s . O c c a s i o n a l l y m a t r i x f e l d s p a r s show a t r a c h y t o i d a l i g n m e n t , w h i l e s a n i d i n e p h e n o c r y s t s t e n d t o form g l o m e r o p o r p h y r i t i c c l o t s up t o 6 mm i n d i a m e t e r . S a n i d i n e c r y s t a l s a r e e u h e d r a l t o s u b h e d r a l and range i n l e n g t h f r o m 0.5 t o 4 mm. C o m p r i s i n g between 40 and 60 p e r c e n t of t h e p h e n o c r y s t mode, t h e s e f e l d s p a r s c o n t a i n a bundant i n c l u s i o n s of f i n e h e m a t i t i c d u s t . S e r i c i t e a n d / o r i l l i t e r e p l a c e s most g r a i n s a s wormy i n t e r g r o w t h s as w e l l a s a l o n g c l e a v a g e p l a n e s and f r a c t u r e s u r f a c e s . B i o t i t e c o m p r i s e s between 5 and 15 p e r c e n t of t h e •p h e n o c r y s t mode, and r a n g e s i n l e n g t h t o a maximum of 1.5 mm. P h e n o c r y s t s a r e g e n e r a l l y e u h e d r a l , a l t h o u g h many a r e b r o k e n and f r a c t u r e d . C h l o r i t e , m a g n e t i t e and h e m a t i t e r e p l a c e most b i o t i t e g r a i n s , w i t h pseudomorphs of m a g n e t i t e a f t e r b i o t i t e c o m p r i s i n g t h e m a j o r i t y of r e l i c c r y s t a l s . P l a g i o c l a s e p h e n o c r y s t s r a n g e i n s i z e from 0.2 mm t o 1.5 mm. S e r c i t e a n d / o r i l l i t e as w e l l a s f i n e g r a i n e d c a r b o n a t e pseudomorphs most g r a i n s , w i t h s u r v i v i n g c r y s t a l s h a v i n g n e g a t i v e r e l i e f , i n d i c a t i n g a l b i t i c c o m p o s i t i o n s . Un i t 17 The f o u r a s h - f l o w t u f f s ( u n i t s 17, 18, 19, 20) w i l l be d i s c u s s e d s e p a r a t e l y , a l t h o u g h t h e y p o s s e s s s i m i l a r w e l d i n g , c r y s t a l l i z a t i o n and d e v i t r i f i c a t i o n t e x t u r e s . 50 D e g r e e o f w e l d i n g t e n d s t o d e c r e a s e up s e c t i o n as does t h e abundance o f l i t h i c f r a g m e n t s . E v i d e n c e f o r v a p o u r phase c r y s t a l l i z a t i o n of m i n e r a l s t e n d s t o be s p o r a d i c , and i s u s u a l l y b e s t p r e s e r v e d i n t h e unwelded r e g i o n s o f a s h f l o w s . V i t r i c a s h t o l a p i l l i t u f f s ( u n i t 17) show low t o m o derate w e l d i n g t e x t u r e s and a r e composed o f 25 t o 65 p e r c e n t d e v i t r i f i e d b r o k e n pumice f r a g m e n t s . Pumice f r a g m e n t s r a n g e from 0.5 t o 1.5 cm i n l e n g t h and a r e g e n e r a l l y c o l l a p s e d , d e s t r o y i n g t h e i r o r i g i n a l v e s i c u l a r and banded i n t e r n a l n a t u r e . L e n g t h t o w i d t h r a t i o s range from 2.5:1 t o 8:1 w i t h t h e more h i g h l y f l a t t e n e d f r a g m e n t s showing p o o r l y d e v e l o p e d fiamme ( P l a t e 3 - 2 0 ) . B o t h t h e a s h m a t r i x and pumice f r a g m e n t s a r e l i g h t brown t o t a n i n p l a n e p o l a r i z e d l i g h t , owing t o t h e abundance o f i r o n o x i d e i n c l u s i o n s . Where w e l d i n g i s o f a h i g h e r d e g r e e , pumice f r a g m e n t s a r e a l i g n e d i m p a r t i n g a e u t a x i t i c f o l i a t i o n t o t h e r o c k . C r y s t a l s o f q u a r t z , b a s a l t i c h o r n b l e n d e , s a n i d i n e and p l a g i o c l a s e r a n g e i n s i z e from 0.5 t o 3 mm and c o m p r i s e between 10 and 20 p e r c e n t o f t h e s e a s h f l o w s . Many q u a r t z g r a i n s a r e embayed, i n d i c a t i n g t h a t a d i s e q u i l i b r i u m e x i s t e d w i t h t h e s u r r o u n d i n g v o l c a n o c l a s t i c m a t r i x d u r i n g c r y s t a l l i z a t i o n ( P l a t e 3-21). B a s a l t i c h o r n b l e n d e s a r e rimmed by i r o n o x i d e s , and have a d a r k g r e e n c o l o u r i n p l a n e p o l a r i z e d l i g h t , a s w e l l as s t r o n g p l e o c h r o i s m ( P l a t e 3-22). P l a g i o c l a s e c r y s t a l s a r e not a b u n d a n t , and a r e s a u s s u r i t i z e d t o a l b i t e , c a r b o n a t e , e p i d o t e , s e r i c i t e a n d / o r i l l i t e . PLATE 3-20: Somewhat f l a t t e n e d pumice fragment i n v i t r i c ash t o l a p i l l i t u f f showing fiamme s t r u c t u r e . Abundant i r o n o x i d e i n c l u s i o n s c l o u d b o t h pumice fragments and groundmass. Width o f photomicrograph i s 1.8 mm. PLATE 3-21: Embayed q u a r t z c r y s t a l i n v i t r i c ash t o l a p i l l i t u f f . Width o f p h o t o m i c r o g r a p h i s 1.8 mm. PLATE 3-22: B a s a l t i c h o r n b l e n d e w i t h r i m o f i r o n o x i d e s i n v i t r i c ash t o l a p i l l i t u f f . Groundmass i s m a i n l y d e v i t r i f i e d v o l c a n i c g l a s s . Width o f photomicrograph i s 1.8 mm. PLATE 3-2 3: Hexagonal q u a r t z c r y s t a l i n v i t r x c - c r y s t a l ash t u f f . Width o f p h o t o m i c r o -graph i s 1.8 mm. 53 D e v i t r i f i c a t i o n of both the ash m a t r i x and pumice c l a s t s ranges from f i n e t o medium g r a n u l a r . I r r e g u l a r p a t c h e s of g r a n o p h y r i c d e v i t r i f i c a t i o n a r e o c c a s i o n a l l y v i s i b l e , a l t h o u g h they tend t o be l o c a l i z e d f e a t u r e s . E v i d e n c e of vapour phase c r y s t a l l i z a t i o n (see Lambert, 1974) i s l a c k i n g , p o s s i b l y as a r e s u l t of compaction and w e l d i n g , d e s t r o y i n g the open space needed f o r c r y s t a l growth. L i t h i c fragments comprise l e s s than 5 p e r c e n t of t h i s ash f l o w . G r a n i t i c i n c o m p o s i t i o n , they a r e subrounded t o s u b a n g u l a r and average 2 t o 7 cm i n d i a m e t e r . The Omineca i n t r u s i v e s are the most l i k e l y s o u r c e of t h e s e x e n o l i t h s . U n i t 18 V i t r i c - l i t h i c ash t u f f s of u n i t 18 a r e non- t o m o d e r a t e l y - w e l d e d and c o n s i s t of 35 t o 55 p e r c e n t a n d e s i t i c and g r a n i t i c c l a s t s s e t i n a m a t r i x of broken pumice fr a g m e n t s , d e v i t r i f i e d g l a s s shards and c r y s t a l s of s a n i d i n e , p l a g i o c l a s e , b i o t i t e , q u a r t z and minor h o r n b l e n d e . Pumice fragments range up t o 2 cm i n l e n g t h and have l e n g t h t o w i d t h r a t i o s a v e r a g i n g 3:1. F i n e t o medium g r a i n e d d e v i t r i f i c a t i o n masks most o r i g i n a l i n t e r n a l f e a t u r e s w i t h i n t h e s e f r a g m e n t s . A weak e u t a x i t i c f a b r i c can o c c a s i o n a l l y be o b s e r v e d . C r y s t a l s have n e a r l y the same morphology and c h a r a c t e r i s t i c s as i n the v i t r i c ash t o l a p i l l i t u f f s ( u n i t 17), a l t h o u g h b i o t i t e i s more abundant than h o r n b l e n d e i n the v i t r i c - l i t h i c t u f f s . L i t h i c c l a s t s a r e p r e d o m i n a n t l y a n d e s i t i c i n n a t u r e 54 a l t h o u g h g r a n i t i c and d a c i t i c c l a s t s a l s o o c c u r . X e n o l i t h s a r e s u b r o u n d e d t o s u b a n g u l a r and have an a v e r a g e d i a m e t e r of between 2 and 10 mm. U n i t 19 P a r t i a l l y - w e l d e d v i t r i c a s h t o l a p i l l i t u f f s a r e composed o f 85 p e r c e n t v i t r o c l a s t i c m a t e r i a l c o n s i s t i n g of d e v i t r i f i e d g l a s s s h a r d s and pumice f r a g m e n t s up t o 6 mm i n l e n g t h . Pumice f r a g m e n t s have l e n g t h t o w i d t h r a t i o s a v e r a g i n g 4.5:1 and have a c o l l a p s e d n a t u r e . W e l l d e v e l o p e d e u t a x i t i c f o l i a t i o n and fiamme a r e a b s e n t , e x c e p t where pumice f r a g m e n t s a r e s u b p a r a l l e l and somewhat a l i g n e d . D e v i t r i f i c a t i o n i s f i n e g r a n u l a r , w i t h a c c i c u l a r l a t h s of p l a g i o c l a s e r e p l a c i n g a l l p u m i c e o u s m a t e r i a l . P l a g i o c l a s e c r y s t a l s a r e i n t u r n pseudomorphed by f i n e a g g r e g a t e s of c h l o r i t e and m i n o r e p i d o t e . The g r e e n i s h - b r o w n c o l o u r of t h e g l a s s i s due t o t h e p r e s e n c e of a b u n d a n t h e m a t i t e i n c l u s i o n s . C r y s t a l s c o m p r i s e l e s s t h a n 15 p e r c e n t of t h i s f l o w and a r e m a i n l y a n h e d r a l t o s u b h e d r a l p l a g i o c l a s e , s a n i d i n e , h o r n b l e n d e , m a g n e t i t e and m i n o r q u a r t z . A l l but t h e q u a r t z g r a i n s have been a l t e r e d by h y d r o t h e r m a l p r o c e s s e s , w i t h s e c o n d a r y m i n e r a l s i n c l u d i n g e p i d o t e , c h l o r i t e , c a r b o n a t e , s e r i c i t e a n d / o r i l l i t e and p y r i t e . U n i t 20 D a c i t i c v i t r i c - c r y s t a l a s h t u f f s o f u n i t 20 a r e w e a k l y w e l d e d t o n o n - welded and have t h e same m i n e r a l o g y and 55 t e x t u r e s as t h e a s h t o l a p i l l i t u f f s , a l t h o u g h pumice f r a g m e n t s a r e much l e s s a b u n d a n t . These a s h - f l o w s c o n s i s t of between 35 and 65 p e r c e n t c r y s t a l s of s a n i d i n e , p l a g i o c l a s e , q u a r t z and b a s a l t i c h o r n b l e n d e . Pumice f r a g m e n t s up t o 6 mm i n l e n g t h and v i t r o c l a s t i c groundmass m a t e r i a l c o m p r i s e s between 15 and 30 p e r c e n t o f t h e s e t u f f s . Q u a r t z a r e t h e most ab u n d a n t c r y s t a l s and e x h i b i t a h e x a g o n a l c r y s t a l form ( P l a t e 3-23), d i s t i n g u i s h i n g them from t h e more a n h e d r a l s a n i d i n e g r a i n s . B a s a l t i c h o r n b l e n d e and p l a g i o c l a s e c r y s t a l s q u i t e c l o s e l y r e s e m b l e t h o s e g r a i n s i n t h e v i t r i c a s h t o l a p i l l i t u f f , a l t h o u g h b r o k e n p l a g i o c l a s e c r y s t a l s t e n d t o be more h i g h l y s a u s s u r i t i z e d i n t h e c r y s t a l t u f f s . P r i s m a t i c sphene and a p a t i t e o c c u r as a c c e s s o r y p h a s e s and r a n g e up t o 0.25 mm i n d i a m e t e r . Pumice f r a g m e n t s a v e r a g e 4 mm i n l e n g t h and have a s q u a r e t o b l o c k y o u t l i n e where n o t c o m p a c t e d . D e v i t r i f i c a t i o n has d e s t r o y e d much of t h e i r o r i g i n a l i n t e r n a l s t r u c t u r e , a l t h o u g h somewhat f l a t t e n e d v e s i c l e s c an o c c a s i o n a l l y be i d e n t i f i e d . L e n g t h t o w i d t h r a t i o s of f r a g m e n t s r a n g e from 1.5:1 t o 3:1, w i t h fiamme, and a w e l l d e f i n e d e u t a x i t i c f o l i a t i o n b e i n g n o t i c a b l y a b s e n t from t h e s e r o c k s . D e v i t r i f i c a t i o n i s f i n e t o medium g r a n u l a r and o c c a s i o n a l l y s p h e r u l i t i c ( P l a t e 3-24). V a p o u r phase c r y s t a l l i z a t i o n o f f i n e g r a i n e d q u a r t z and f e l d s p a r i s p o o r l y d e v e l o p e d , but i s b e s t e x h i b i t e d i n a r e a s where c o m p a c t i o n i s e x t r e m e l y low. S u b r o u n d e d l i t h i c f r a g m e n t s a r e g r a n i t i c i n c o m p o s i t i o n , and a v e r a g e 2 t o 10 mm i n d i a m e t e r . More 56 abundant i n the lower p a r t s of t h i s f l o w , g r a n i t i c c l a s t s g e n e r a l l y compose l e s s than 2 p e r c e n t of t h i s u n i t . U n i t 21 V o l c a n i c greywackes of U n i t 21 are s i m i l a r t o the greywackes of U n i t 15, a l t h o u g h a n d e s i t i c c l a s t s a r e a l s o accompanied by d a c i t i c c l a s t s w i t h i n t h i s uppermost u n i t of the Toodoggone assemblage. A l t e r a t i o n A l t e r a t i o n of Toodoggone v o l c a n i c r o c k s can be d i v i d e d i n t o two t y p e s : o x i d a t i o n as a r e s u l t of emplacement i n a s u b a e r i a l environment, and a l t e r a t i o n by h y d r o t h e r m a l f l u i d s ; the l a t t e r g r e a t l y a f f e c t s the m i n e r a l o g i c a l and t e x t u r a l c h a r a c t e r i s t i c s of the v o l c a n i c s . ' F i v e d i s t i n c t h y d r o t h e r m a l a l t e r a t i o n assemblages can be r e c o g n i z e d w i t h i n the Toodoggone a n d e s i t e s and d a c i t e s ; t hese i n c l u d e p r o p y l i t i c , z e o l i t i c , i n e r m e d i a t e and advanced a r g i l l i c , p o t a s s i c and s i l i c i c f a c i e s . A c o r e of i n t e r m e d i a t e t o advanced a r g i l l i c a l t e r a t i o n w i t h s p o r a d i c s i l i c i c and p o t a s s i c zones i s surrounded by p r o p y l i t i c and z e o l i t i c a l t e r a t i o n ( F i g u r e 3-4). I d e a l l y t h e s e zones form a c o n c e n t r i c p a t t e r n , a l t h o u g h both l a t e r a l and v e r t i c a l z o n i n g of a l t e r a t i o n o c c u r s . P r o p y l i t i c a l t e r a t i o n i s w i d e s p r e a d throughout the Toodoggone R i v e r a r e a , and g r e a t l y e f f e c t s a n d e s i t e f l o w s and t u f f s . P e r v a s i v e i n i t s d i s t r i b u t i o n , p r o p y l i t i c zones ar e c h a r a c t e r i z e d by c h l o r i t i z a t i o n of p l a g i o c l a s e , L E G E N D FIGURE 3-4 Argillic/Advanced Argillic Silicic (Includes Sinter) Potassic Propylitic Zeolitic Fault >ANDESITES DACITES 59 h o r n b l e n d e and b i o t i t e p h e n o c r y s t s , s a u s s u r i t i z a t i o n o f p l a g i o c l a s e , as w e l l as i n c r e a s e d e p i d o t e , s e r i c i t e a n d / o r i l l i t e , c a r b o n a t e , p y r i t e and m a g n e t i t e i n t h e groundmass. A l t e r a t i o n o f t h i s f o r m i n v a r i b l y i m p a r t s a g r e y - g r e e n t o d a r k g r e e n c o l o u r t o t h e a n d e s i t e s . D a c i t i c a s h f l o w s a r e not g e n e r a l l y e f f e c t e d by t h i s form of a l t e r a t i o n , a l t h o u g h p l a g i o c l a s e and h o r n b l e n d e p h e n o c r y s t s o c c a s i o n a l l y a r e pseudomorphed by c h l o r i t e . P r o p y l i t i c z o n e s g r a d e l a t e r a l l y i n t o a r g i l l i c a l l y a l t e r e d r e g i o n s as t h e n u c l e u s of h y d r o t h e r m a l s y s t e m s i s a p p r o a c h e d . A r g i l l i c a l l y a l t e r e d r o c k s a r e c h a r a c t e r i z e d by a w h i t e t o y e l l o w i s h - o r a n g e c o l o u r anomaly as t h e c o n s t i t u e n t p h e n o c r y s t s a r e r e p l a c e d by c l a y m i n e r a l s , s e r i c i t e a n d / o r i l l i t e and a l u n i t e ( P l a t e 3 - 2 5 ) . The o r i g i n a l p o r p h y r i t i c t e x t u r e o f t h e a n d e s i t e s i s c o m p l e t e l y d e s t r o y e d , w i t h - o n l y r e l i c o u t l i n e s of p l a g i o c l a s e and m a f i c g r a i n s r e m a i n i n g . In t h e Toodoggone R i v e r a r e a t h e s e b l e a c h e d z o n e s may c o n t a i n t h e m i n e r a l s k a o l i n i t e , m o n t m o r i l l o n i t e , i l l i t e , d i c k i t e , a l u n i t e and minor b a r i t e ( A p p e n d i x E ) . A r g i l l i c a l l y a l t e r e d z o n e s f r e q u e n t l y have a c i r c u l a r o u t l i n e , and may have a d i a m e t e r of up t o 2 km. A l t e r a t i o n of t h i s f o r m i s s a i d t o be be c h a r a c t e r i s t i c of p a t t e r n s t h a t d e v e l o p as a r e s u l t o f l e a c h i n g of p r i m a r y m i n e r a l s by d e s c e n d i n g h y d r o t h e r m a l f l u i d s (Buchanan, 1983; Schoen, e t a l . , 1974). Zones of s i l i c i f i c a t i o n and g o l d - s i l v e r m i n e r a l i z a t i o n do n o t seem t o be c o n t r o l l e d by l i t h o l o g y , a l t h o u g h t h e y t e n d t o f a v o u r t h e more c o m p e t e n t a n d e s i t e f l o w s and f l o w 1 60 PLATE 3-24: S p h e r u l i t i c d e v i t r i f i c a t i o n o f v i t r i e - c r y s t a l a s h t u f f . Note v a p o u r p h a s e c r y s t a l l i z a t i o n o f a l k a l i f e l d s p a r and q u a r t z a t c e n t e r o f s p h e r u l i t e . W i d t h o f p h o t o m i c r o -g r a p h i s 0.9 mm. PLATE 3-25: G o s s a n i n a r g i l l i c a l l y a l t e r e d t u f f s o n t h e GWP 1 t o 10 p r o p e r t y . Mt. G r a v e s i s v i s i b l e i n t h e b a c k g r o u n d . W i d t h o f p h o t o g r a p h i n f o r e g r o u n d i s a p p r o x i m a t e l y 20 0 m e t r e s . 61 c o n t a c t s o v e r t h e p y r o c l a s t i c u n i t s . S i l i c i f i c a t i o n i s c h a r a c t e r i z e d by a s t o c k w o r k o f a m e t h y s t i n e , m i l k y , c h a l c e d o n i c and j a s p e r o i d a l q u a r t z as w e l l a s t h e i n t r o d u c t i o n of abundant h e m a t i t e and manganese s t a i n i n g . S e c o n d a r y q u a r t z i s p e r v a s i v e t h r o u g h o u t s i l i c i f i e d z o n e s w i t h i n a n d e s i t e f l o w s , p s e u d o m o r p h i n g a l l p h e n o c r y s t s . M a j o r s i l i c i f i e d and b r e c c i a t e d z o n e s w i t h p r e c i o u s m e t a l m i n e r a l i z a t i o n o c c u r a t t h e Moosehorn, L a w y e r s and C l i f f C r e e k p r o s p e c t s ( P l a t e I ) . S i l i c e o u s s i n t e r i s i n c l u d e d w i t h i n t h i s a l t e r a t i o n f a c i e s as i t i s o f t e n d i f f i c u l t t o d i s t i n g u i s h s i n t e r f r o m p e r v a s i v e l y s i l i c i f i e d v o l c a n i c s i n a r g i l l i c a l l y a l t e r e d z o n e s . P o t a s s i c a l t e r a t i o n g e n e r a l l y a c c o m p a n i e s s i l i c i f i c a t i o n and i s r e c o g n i z e d by p o t a s s i u m f e l d s p a r s r e p l a c i n g p l a g i o c l a s e p h e n o c r y s t s , as w e l l as by t h e i n t r o d u c t i o n of s i g n i f i c a n t amounts of s e c o n d a r y b i o t i t e and c a r b o n a t e . S c h r o e t e r (1982) s t a t e s t h a t a d u l a r i a i s t h e most common s e c o n d a r y p o t a s s i u m f e l d s p a r i n t h e h y d r o t h e r m a l l y a l t e r e d r e g i o n s w i t h i n t h e Toodoggone a n d e s i t e s , a l t h o u g h t h e c h a r a c t e r i s t i c diamond shaped c r y s t a l s seem t o be a b s e n t from t h e s e z o n e s . P o t a s s i c a l l y a l t e r e d r e g i o n s g r a d e l a t e r a l l y i n w a r d as w e l l as v e r t i c a l l y i n t o s i l i c i f i e d a r e a s w i t h i n a n d e s i t e s . S i l i c i f i e d z o n e s may e x t e n d f o r h u n d r e d s o f m a l o n g s t r i k e and have w i d t h s of up t o 75 m. R e c e n t d r i l l i n g i n t h e Toodoggone R i v e r a r e a i n d i c a t e s t h a t b r e c c i a t e d and s i l i c i f i e d z o n e s do not e x t e n d v e r t i c a l l y f o r more t h a n 200 m. D a c i t i c a s h - f l o w t u f f s a r e g e n e r a l l y u n a f f e c t e d by 62 p r o p y l i t i c , a r g i l l i c , p o t a s s i c and s i l i c i c a l t e r a t i o n s . These u n i t s are more commonly z e o l i t i z e d , w i t h 2 t o 5 cm v e i n s of l a u m o n t i t e , n a t r o l i t e , c a l c i t e and r a r e f l u o r i t e . C h a r a c t e r i s t i c a l l y these z e o l i t i z e d zones a r e p i n k t o p i n k i s h - w h i t e r e s u l t i n g from l a u m o n t i t e and c a l c i t e r e s p e c t i v e l y ( P l a t e 3-26). A n d e s i t e s do not appear t o be z e o l i t i z e d , a l t h o u g h the i n t e n s i t y of o t h e r forms of a l t e r a t i o n may mask the l e s s i n t e n s e z e o l i t i c a l t e r a t i o n . H y d r o t h e r m a l a l t e r a t i o n found i n the Toodoggone v o l c a n i c s i s s i m i l a r t o the a l t e r a t i o n s t y l e s and t y p e s found i n a c t i v e geothermal systems i n New Zealand and Nevada (Schoen et a l . , 1974; W e i s s b e r g , 1969; Schwartz, 1959 and White e t a l . , 1981). F o s s i l geothermal systems i n Nevada and C o l o r a d o a l s o e x h i b i t s i m i l a r a l t e r a t i o n p a t t e r n s and c o n t a i n g o l d and s i l v e r m i n e r a l i z a t i o n (Whitebread, 1976; A s h l e y e t a l . , 1976 and Burbank e t a l . , 1969). S t r u c t u r e Toodoggone v o l c a n i c r o c k s on a r e g i o n a l s c a l e d i s p l a y broad open f o l d s w i t h d i p s on the l i m b s of between 7 and 25 d e g r e e s . In the s t u d y - a r e a they form the south-west l i m b of a n o r t h - w e s t e r l y s t r i k i n g a n t i c l i n e ( P l a t e I I I ) . To the s o u t h , where r o t a t i o n and t i l t i n g of f a u l t b l o c k s has o c c u r r e d t o a g r e a t e r degree, Toodoggone r o c k s d i p between 25 and 55 degrees ( P a n t e l e y e v , 1982). Toodoggone v o l c a n i c r o c k s a r e s t r u c t u r a l l y c o nformable w i t h the T a k l a v o l c a n i c s i n the s t u d y - a r e a , a l t h o u g h t o the s o u t h , they may o v e r l i e them w i t h a s l i g h t a n g u l a r PLATE 3-26: H i g h l y f r a c t u r e d v i t r i c ash t o Tapilli t u f f w i t h v e i n s o f l a u m o n t i t e and c a l c i t e . Width o f photograph i s a p p r o x i m a t e l y 5 m e t r e s . 64 u n c o n f o r m i t y ( P a n t e l e y e v , 1983). S t e e p l y d i p p i n g H a z e l t o n v o l c a n i c r o c k s a r e g e n e r a l l y i n f a u l t c o n t a c t w i t h Toodoggone r o c k s , a s a r e t h e Omineca i n t r u s i v e s . The Toodoggone R i v e r a r e a i s c r o s s e d by numerous n o r t h , n o r t h e a s t and n o r t h w e s t t r e n d i n g , s t e e p l y d i p p i n g f a u l t s , t h a t d e f i n e most o f t h e b o u n d a r i e s between d i f f e r e n t l i t h o l o g i c u n i t s ( P l a t e s I and I I I ) . F a u l t s a r e g e n e r a l l y d e f i n e d by an a b r u p t change i n l i t h o l o g y , w i t h w e l l d e f i n e d s c a r p s o c c a s i o n a l l y b e i n g p r e s e n t . Normal f a u l t i n g o c c u r r e d i n t h e r e g i o n from t h e E a r l y J u r a s s i c t o C r e t a c e o u s ( S c h r o e t e r , 1980). F r e s h q u a r t z - f e l d s p a r p o r p h y r y d y k e s , p e r h a p s o f C r e t a c e o u s o r T e r t i a r y age, c r o p o ut on t h e S i l v e r p o n d p r o p e r t y and a r e o f f s e t by a s e r i e s o f en e c h e l o n f a u l t s i n d i c a t i n g t h a t a r e l a t i v e l y young phase of f a u l t i n g a l s o a f f e c t e d t h e r e g i o n . Age The age of t h e Toodoggone v o l c a n i c s has been w e l l e s t a b l i s h e d i n r e c e n t y e a r s by b o t h K-Ar and Rb-Sr t e c h n i q u e s . T a b l e 3-1 l i s t s t h e p u b l i s h e d age d e t e r m i n a t i o n s f o r b o t h t h e Toodoggone v o l c a n i c s and r e l a t e d p l u t o n i c r o c k s i n n o r t h - c e n t r a l B r i t i s h C o l u m b i a . D a t e s range from 204 + 7 Ma ( P a n t e l e y e v , 1983) t o 182 + 8 Ma ( G a b r i e l s e e t a l . , 1980). R e l a t e d p l u t o n i c r o c k s , e s s e n t i a l l y c o e v a l w i t h t h e f o r m a t i o n of t h e Toodoggone v o l c a n i c s , r a n g e i n age from 207+7 Ma ( C h u r c h , 1974) t o 182+6 Ma (Cann and Godwin, 1980). A l t e r a t i o n o f t h e Toodoggone v o l c a n i c s by h y d r o t h e r m a l Table 3-1 Published Age Dates f o r the Toodoggone Volcanics and Related Plutonic Rocks i n North-Central B r i t i s h Columbia Author Carter (1972) Church (1974, 1975) Erdman (1978) Gabrielse et_ a l . (1980) General  Rock  C l a s s i f i c a t i o n Volcanic Plutonic Plutonic Volcanic Volcanic Plutonic Plutonic Volcanic Volcanic Volcanic Volcanic Approximate  Longitude and  Latitude 126°55'W 57°12'N 126°46'W 56°30'N 126°42'W 56°28'N 129°05'W 58°01'N 129°05*W 57°41'N 128°03'W 58°03'N 128°03'W 58°03'N 127°23'W 57°28'N 126°46'W 56°30'N 127°01'W 57°16'N 126°42'W 57°08'N Dating  Method K-Ar K-Ar K-Ar Rb-Sr Rb-Sr K-Ar Rb-Sr Rb-Sr Rb-Sr K-Ar K-Ar Sample  Type hornblende hornblende hornblende whole rock isochron whole rock isochron hornblende whole rock isochron whole rock isochron whole rock isochron hornblende hornblende Approximate  Location Drybrough Peak Sustut Peak Sustut Peak Mt. S i s t e r Mary Mt. S i s t e r Mary Mt. B l a i r Mt. B l a i r Near Oxide Peak Age 189±6Ma 193±llMa 191±6Ma 191±9Ma 189±13Ma 162±6Ma 1 182±18Ma 185±5Ma Southwest of 185±3Ma Sustut Peak near Drybrough 182±8Ma Peak near Drybrough 183±8Ma Peak General Rock Approximate  Longitude and Author C l a s s i f i c a t i o n Latitude Cann and Godwin (1980) Plutonic Plutonic Plutonic Plutonic Plutonic Plutonic Plutonic Plutonic Plutonic Plutonic Schroeter (1981) Alunite M i n e r a l i z a t i o n Panteleyev (1983) Volcanic 127°16'W 58°03'N 127°02'W 57°09'N 126°53'W 57°36'N 126°45'W 57°03*N 126°46'W 57°03'N 126°46'W 57°03'N 126°46'W 57°03'N 126°46'W 57°03'N 126°46'W 57°03'N 126°46'W 57°03'N 127°36'W 57°05'N 126°39'W 57°05'N Dating  Method K-Ar K-Ar K-Ar K-Ar K-Ar K-Ar Rb-Sr Rb-Sr K-Ar K-Ar K-Ar K-Ar Sample T^pe. hornblende b i o t i t e b i o t i t e hornblende b i o t i t e whole rock b i o t i t e hornblende whole rock isochron whole rock isochron b i o t i t e hornblende a l u n i t e b i o t i t e Approximate Location near Thomas Peak near Mt. Cushing Kemess Property Kemess Property Kemess Property Kemess Property Kemess Property Kemess Property Kemess Property Alberts Hump Kemess Property Age 182±13Ma 193±7Ma 190±8Ma 182±6Ma 182±6Ma 207±7Ma 190±9Ma 191±4Ma 178 Ma 208 Ma 190±7Ma 204±7Ma 1. Sample showed e x t e n s i v e a l t e r a t i o n . 67 f l u i d s appears to be synchronous with t h e i r d e p o s i t i o n . Schroeter (1982) obtained a K-Ar age date of 190+7 Ma on a l u n i t e a l t e r a t i o n from the Toodoggone R i v e r area. T h e r e f o r e , p u b l i s h e d data suggest that the Toodoggone v o l c a n i c s were d e p o s i t e d w i t h i n a 20 m i l l i o n year or s h o r t e r p e r i o d d u r i n g the E a r l y J u r a s s i c . 3.4 I n t r u s i v e Rocks  General Geology Un i t 6 P o r p h y r i t i c quartz monzonite stocks of u n i t 6 invade Toodoggone, Hazelton and Takla v o l c a n i c s i n the Toodoggone River a r e a . They are medium gr a i n e d and composed of q u a r t z , o r t h o c l a s e , p l a g i o c l a s e and hornblende. Although the type and abundance of phenocrysts may change with l o c a t i o n w i t h i n the i n t r u s i v e , these stocks are r e l a t i v e l y homogeneous i n compositon and do not appear to be zoned. At the c o n t a c t between quartz monzonite i n t r u s i o n s and the Toodoggone and Hazelton v o l c a n i c s , i n t r u d e d rocks tend to be chalky white and a l t e r e d to c l a y s i n d i c a t i v e of a r g i l l i c a l t e r a t i o n . Numerous rounded x e n o l i t h s of green a n d e s i t e up to 7 cm i n diameter occur w i t h i n the margins of the i n t r u s i o n s . • Dykes of quartz monzonite up to 10 metres wide invade v o l c a n i c rocks adjacent to these s t o c k s , and d i p s t e e p l y . U n i t 22 Fresh q u a r t z - f e l d s p a r porphyry dykes ( u n i t 22) are h i g h l y r e s i s t a n t to weathering ( P l a t e 3-27), and c o n s i s t of PLATE 3-27: R h y o l i t e dyke p r o t r u d i n g from r e c e s s i v e l y weathered a n d e s i t e s . Width o f r h y o l i t e dyke i s a p p r o x i m a t e l y 2 m e t r e s . 69 phenocrysts of q u a r t z , p l a g i o c l a s e and s a n i d i n e i n a m i c r o c r y s t a l l i n e matrix. These b r i g h t orange r h y o l i t i c dykes have widths ranging from 2 to 35 m and can be t r a c e d f o r hundreds of m along s t r i k e . Contacts with v o l c a n i c rocks are sharp with d i p s ranging from 55 degrees to n e a r l y v e r t i c a l . U n i t 23 Pyroxene a n d e s i t e s . f o r m dykes and s i l l s , and are much more r e s i s t a n t than the r e c e s s i v e l y weathering v o l c a n i c s . These i n t r u s i v e s are c h a r a c t e r i z e d by p o r p h y r i t i c t e x t u r e s and phenocrysts of p l a g i o c l a s e and pyroxene set i n an a p h a n i t i c matrix of p l a g i o c l a s e , c h l o r i t e and magnetite. Dykes are g e n e r a l l y grey-green to dark green and range in width from l e s s than one to over 25 m. One dyke near the cen t r e of the.map-area ( P l a t e I) i s approximately 85 m i n width . Dykes d i p 55 degrees to near v e r t i c a l and many s t r i k e northwest, although trends are not c o n s i s t a n t . P e t r o l o g y U n i t 6 Quartz monzonite i n t r u s i o n s of u n i t 6 are hypidiomorphic and e q u i g r a n u l a r with the c h i e f m i n e r als i n c l u d i n g p l a g i o c l a s e , o r t h o c l a s e , quartz and hornblende. P l a g i o c l a s e g r a i n s range from 2 to 3 mm i n l e n g t h and have subhedral to euhedral o u t l i n e s . They are unzoned and compositions range from An8 to An30. V a r i a b l e compositions can be a t t r i b u t e d to the e f f e c t s of s a u s s u r i t i z a t i o n , with many g r a i n s h a v i n g wormy i n t e r g r o w t h s o f s e r i c i t e and minor c a r b o n a t e . In many p h e n o c r y s t s , h e m a t i t e o c c u r s a s s u b m i c r o s c o p i c i n c l u s i o n s , i m p a r t i n g a r e d d i s h - b r o w n d i s c o l o u r a t i o n . H o r n b l e n d e s a r e e u h e d r a l t o s u b h e d r a l , w i t h most g r a i n s h a v i n g been a l t e r e d t o c h l o r i t e and minor e p i d o t e . I r o n o x i d e s o c c u r a s i r r e g u l a r b l e b s w i t h i n h o r n b l e n d e s , as w e l l as rimming most g r a i n s . O r t h o c l a s e and q u a r t z form i n t e r s t i t i a l l y t o p l a g i o c l a s e and h o r n b l e n d e and a r e e s s e n t i a l l y u n a l t e r e d . B o t h q u a r t z and o r t h o c l a s e g r a i n s have u n d u l a t o r y e x t i n c t i o n and may o c c a s i o n a l l y show m i c r o g r a p h i c t e x t u r e s . U n i t 22 R h y o l i t e d y k e s ( u n i t 22) a r e c h a r a c t e r i z e d by p h e n o c r y s t s of s a n i d i n e , q u a r t z , p l a g i o c l a s e and minor h o r n b l e n d e , s e t i n a groundmass of c r y p t o c r y s t a l l i n e q u a r t z and p o t a s s i u m f e l d s p a r . P l a g i o c l a s e p h e n o c r y s t s c o n s i s t o f between 15 and 25 p e r c e n t of t h e p h e n o c r y s t mode and have e u h e d r a l t o s u b h e d r a l o u t l i n e s . G r a i n s r a n g e i n l e n g t h up t o 4 mm, a r e unzoned, and form g l o m e r o p o r p h y r i t i c c l o t s up t o 7 mm i n d i a m e t e r . A l l c r y s t a l s a r e pseudomorphed by s e r i c i t e and c a r b o n a t e , making i t i m p o s s i b l e t o d e t e r m i n e p l a g i o c l a s e c o m p o s i t i o n s . S a n i d i n e and q u a r t z p h e n o c r y s t s have s i m i l a r m o r p h o l o g i e s t o t h e p l a g i o c l a s e g r a i n s , f o r m i n g s u b h e d r a l c r y s t a l s w i t h d i a m e t e r s of up t o 4.5 mm. Q u a r t z c r y s t a l s a r e o c c a s i o n a l l y embayed i n d i c a t i n g t h a t a d i s e q u i l i b r i u m e x i s t e d between t h e p h e n o c r y s t s and t h e 71 groundmass a f t e r c r y s t a l l i z a t i o n . H o r n b l e n d e p h e n o c r y s t s c o m p r i s e l e s s t h a n one p e r c e n t of t h e s e r o c k s and have s u b h e d r a l o u t l i n e s and l e n g t h s of up t o 0.5 mm. C h l o r i t e w i t h i n c l u s i o n s o f i r o n o x i d e s pseudomorphs most g r a i n s , w i t h o n l y r e l i c diamond s h a p e d a m p h i b o l e o u t l i n e s r e m a i n i n g . U n i t 23 P y r o x e n e a n d e s i t e s a r e c h a r a c t e r i z e d by p h e n o c r y s t s o f p l a g i o c l a s e and c l i n o p y r o x e n e s e t i n an a p h a n i t i c groundmass of p l a g i o c l a s e l a t h s , c h l o r i t e and m a g n e t i t e , and o t h e r i r o n o x i d e s . P h e n o c r y s t s make up between 15 and 55 p e r c e n t o f t h e s e r o c k s and a r e g e n e r a l l y e u h e d r a l i n o u t l i n e . P l a g i o c l a s e c o m p r i s e s between 50 and 75 p e r c e n t o f t h e p h e n o c r y s t mode and r a n g e s i n l e n g t h from 0.5 mm t o 2.5 mm. E u h e d r a l - g r a i n s a r e g e n e r a l l y unzoned and have p l a g i o c l a s e c o m p o s i t i o n s r a n g i n g from An30 t o An48. In some d y k e s and s i l l s , h y d r o t h e r m a l a l t e r a t i o n has c a u s e d p l a g i o c l a s e g r a i n s t o be s e r i c i t i z e d o r c h l o r i t i z e d , making i t d i f f i c u l t t o d e t e r m i n e p l a g i o c l a s e c o m p o s i t i o n s . Groundmass p l a g i o c l a s e l a t h s o c c a s i o n a l l y show a t r a c h y t i c t e x t u r e . C l i n o p y r o x e n e p h e n o c r y s t s range i n d i a m e t e r from 0.25 t o 1.5 mm. They c o m p r i s e between 10 and 35 p e r c e n t of t h e p h e n o c r y s t mode and a r e u n a l t e r e d , h a v i n g w e l l f o r m e d t w i n s . Age Age r e l a t i o n s h i p s between i n t r u s i v e r o c k s i n t h e Toodoggone R i v e r a r e a a r e ambiguous as a r e s u l t of t h e l a c k of o b s e r v e d c r o s s c u t t i n g r e l a t i o n s h i p s . The o l d e s t 72 i n t r u s i v e r o c k s i n t h e s t u d y - a r e a a r e t h e q u a r t z m o n z o n i t e s t o c k s ( u n i t 6) b e l o n g i n g t o t h e Omineca Group of T r i a s s i c t o J u r a s s i c age ( T a b l e 3 - 1 ) . P y r o x e n e a n d e s i t e d y k e s a r e g e n e r a l l y u n a l t e r e d , s u g g e s t i n g t h a t t h e y a r e r e l a t i v e l y young and p o s t d a t e much of t h e h y d r o t h e r m a l a c t i v i t y i n t h e r e g i o n . A n d e s i t e d y k e s c u t r h y o l i t e d y k e s i n t h e v i c i n i t y of Mt. G r a v e s , but t h e y were not s e p a r a t e d by a g r e a t t i m e p e r i o d as t h e r h y o l i t e s a l s o a p p e a r t o be u n a f f e c t e d by h y d r o t h e r m a l a l t e r a t i o n . T h e r e a p p e a r s t o have been a t l e a s t two p h a s e s of p y r o x e n e a n d e s i t e i n t r u s i o n , b e c a u s e t h e l a r g e dyke i n t h e c e n t e r o f t h e map-area ( P l a t e I) has u n d e r g o n e s t r o n g h y d r o t h e r m a l a l t e r a t i o n , whereas t h e s m a l l a n d e s i t e d y k e s w i t h i n t h e same r e g i o n a p p e a r t o be u n a l t e r e d . 3.5 G e o l o g i c a l H i s t o r y The Toodoggone v o l c a n i c a s s e m b l a g e r e p r e s e n t s a s u b a e r i a l , v o l c a n i c f l o w and p y r o c l a s t i c a c c u m u l a t i o n t h a t may have been c o n f i n e d t o a n o r t h - w e s t e r l y t r e n d i n g i s l a n d a r c . Near t h e end o f L a t e T r i a s s i c t i m e , m a r i n e d e p o s i t i o n of T a k l a v o l c a n i c s i n an a r c e n v i r o n m e n t was i n t e r r u p t e d by r e g i o n a l u p l i f t ( T i p p e r and R i c h a r d s , 1 9 7 6 ) . In t h e Toodoggone R i v e r a r e a v o l c a n i s m was r e a c t i v a t e d i n t h e E a r l y J u r a s s i c w i t h t h e d e p o s i t i o n of Toodoggone a n d e s i t e f l o w s on a L a t e T r i a s s i c e r o s i o n a l s u r f a c e . To t h e e a s t , v o l c a n i c s of t h e H a z e l t o n G roup were a l s o e r u p t i n g s i m u l t a n e o u s l y w i t h t h e Toodoggone e v e n t , i n t h e no n - m a r i n e H a z e l t o n T r o u g h 73 ( T i p p e r and R i c h a r d s , 1 9 76). A b r i e f e p i s o d e of p y r o c l a s t i c v o l c a n i s m f o l l o w e d t h e e r u p t i o n o f a n d e s i t e f l o w s and i s r e p r e s e n t e d by t h e a c c u m u l a t i o n o f bomb s i z e d c l a s t s and minor f l o w b r e c c i a . T h i s e v e n t was p r o b a b l y f a i r l y l o c a l i z e d , w i t h l e s s v i o l e n t e r u p t i o n s o f l a v a p r o b a b l y c o n t i n u i n g i n o t h e r p a r t s of t h e i s l a n d c h a i n . E r u p t i o n s of v o l u m i n o u s a n d e s i t e f l o w s c o n t i n u e d d u r i n g t h e e a r l y J u r a s s i c w i t h t h e magma u n d e r g o i n g l i t t l e o r no d i f f e r e n t i a t i o n . R e l a t i v e l y s m a l l , i s o l a t e d magma chambers p r o d u c e d l o c a l i z e d t r a c h y t i c f l o w s w h i c h i n t e r f i n g e r e d w i t h t h e a n d e s i t e s . A f t e r t h e a c c u m u l a t i o n o f o v e r 600 m o f a n d e s i t e l a v a , t r a c h y t e f l o w s and minor p y r o c l a s t i c m a t e r i a l , a p e r i o d of v o l c a n i c q u i e s c e n c e e n s u e d . D u r i n g t h i s p e r i o d o f v o l c a n i c i n a c t i v i t y , e r o s i o n a l p r o c e s s e s d e p o s i t e d e p i c l a s t i c s a n d s t o n e s i n b o t h s u b a e r i a l and s u b m a r i n e e n v i r o n m e n t s . B l o c k f a u l t i n g ended t h e p e r i o d of q u i e s c e n c e , and may have been i n i t i a t e d by t h e renewed i n t r u s i o n of magma b e n e a t h t h e v o l c a n i c f i e l d , a s was t h e c a s e w i t h f a u l t i n g i n t h e C r e e d e V o l c a n i c D i s t r i c t o f C o l o r a d o ( S t e v e n e t a l . , 1975). T h e s e i n t r u s i o n s were a l s o r e s p o n s i b l e f o r i n i t i a t i n g c o n v e c t i o n t h a t c i r c u l a t e d g r o u n d w a t e r s , l e a d i n g t o t h e l e a c h i n g and l o c a l i z a t i o n of g o l d and s i l v e r a l o n g f a u l t z o n e s w i t h i n t h e a n d e s i t e s i n th e Toodoggone R i v e r a r e a . V o l c a n i s m was a g a i n renewed w i t h t h e d e p o s i t i o n of v o l u m i n o u s d a c i t i c a s h - f l o w t u f f s . The change from t h e e r u p t i o n o f a n d e s i t e s t o more s i a l i c a s h f l o w s i s s i m i l a r t o t h e r e c o r d e d e v o l u t i o n o f t h e San Juan v o l c a n i c f i e l d , and 74 l i k e l y r e s u l t e d as t h e b a t h o l i t h d i f f e r e n t i a t e d b e n e a t h t h e v o l c a n i c p i l e ( S t e v e n and Lipman, 1976). S i m i l a r l y , t h e m o d i f i c a t i o n of mode o f e r u p t i o n f r o m l a v a f l o w s t o e x p l o s i v e v o l c a n i s m may have been t h e r e s u l t o f an i n j e c t i o n o f b a s i c magma i n t o t h e chamber, r e s u l t i n g i n s u p e r h e a t i n g as w e l l a s i n c r e a s e d c o n v e c t i o n and v e s i c u l a t i o n , t r i g g e r i n g an e x p l o s i v e e r u p t i o n ( S p a r k s e t a l . , 1977). The p r e p o n d e r a n c e of d a c i t i c a s h f l o w s c o u l d be e x p l a i n e d by c a u l d r o n s u b s i d e n c e a s p o s t u l a t e d by R a t t e and S t e v e n (1967) f o r t h e c y c l i c v o l c a n i s m r e c o g n i z e d i n p a r t s o f C o l o r a d o . T h i s r e a s o n i n g i s s u p p o r t e d by t h e d i s t r i b u t i o n of g o s s a n s , s u g g e s t i n g a s e m i c i r c u l a r p a t t e r n a b o u t 35 km i n l e n g t h and 25 km i n w i d t h , w i t h i n t h e Toodoggone R i v e r a r e a . Such an e v e n t would a l s o e x p l a i n why no s o u r c e of t h e Toodoggone v o l c a n i c s h as been f o u n d . The magma w h i c h f e d t h e a s h e r u p t i o n s may have been z o n e d , a s i n d i c a t e d by t h e i n c r e a s e o f p h e n o c r y s t s upward, a l t h o u g h major c o m p o s i t i o n a l z o n i n g ( S m i t h , 1979) i s a b s e n t . A s e c o n d p e r i o d of v o l c a n i c q u i e s c e n c e f o l l o w e d t h e e r u p t i o n o f a s h - f l o w s h e e t s and r e s u l t e d i n t h e e r o s i o n and d e p o s i t i o n of f u r t h e r e p i c l a s t i c u n i t s . Movement o f f a u l t b l o c k s c o n t i n u e d i n t h e r e g i o n , p r o b a b l y u n t i l T e r t i a r y t ime. P l u t o n i c a c t i v i t y w i t h i n t h e r e g i o n was c h a r a c t e r i z e d by t h e i n t r u s i o n o f q u a r t z m o n z o n i t e s t o c k s and m i n o r d y k e s . As w e l l , s e v e r a l p e r i o d s o f a n d e s i t e and r h y o l i t e dyke emplacement f o l l o w e d t h e q u a r t z m o n z o n i t e i n t r u s i o n s . C i r c u l a t i o n of h y d r o t h e r m a l f l u i d s d r i v e n by t h e h e a t f rom i n t r u d i n g s t o c k s , f u r t h e r e n h a n c e d t h e low g r a d e a l t e r a t i o n a l r e a d y p r e v a l e n t w i t h i n t h e r e g i o n . U p l i f t and e r o s i o n removed some of t h e v o l c a n i c c o v e r , e x p o s i n g Omineca q u a r t z m o n z o n i t e i n t r u s i o n s , as w e l l as T a k l a v o l c a n i c s i n t h e e a s t e r n and s o u t h e r n p o r t i o n s of t h e map-area. S u s t u t c o n g l o m e r a t e , d e p o s i t e d on t h e Upper M e s o z o i c e r o s i o n a l s u r f a c e , t h e m s e l v e s have u n d e r g o n e f u r t h e r t i l t i n g , u p l i f t and e r o s i o n t h r o u g h T e r t i a r y t i m e . 76 CHAPTER 4 CHEMISTRY OF THE TOODOGGONE VOLCANICS 4.1 I n t r o d u c t i o n C h e m i c a l a n a l y s e s o f Toodoggone v o l c a n i c s have been r e p o r t e d by T i p p e r and R i c h a r d s ( 1 9 7 6 ) , Erdman (1978) and S c h r o e t e r ( 1 9 8 1 ) . T h e s e d a t a , a l t h o u g h l i m i t e d i n number, c l e a r l y show t h e s u b a l k a l i n e n a t u r e of t h e s u i t e . A more e x t e n s i v e d a t a s e t was needed, however, i n o r d e r t o d e f i n e more p r e c i s e l y t h e c h e m i c a l c h a r a c t e r i s t i c s of t h e Toodoggone v o l c a n i c s and t h e i r a l t e r a t i o n p r o d u c t s . T h i r y - t w o samples o f r e l a t i v e l y f r e s h Toodoggone v o l c a n i c s were c o l l e c t e d f o r a n a l y s i s ( P l a t e I I ) . A l l r o c k was o b t a i n e d from s u r f a c e e x p o s u r e s w i t h i n t h e s t u d y - a r e a ; w e a t h e r i n g r i n d s were removed b e f o r e p u l v e r i z a t i o n . Samples of h y d r o t h e r m a l l y a l t e r e d v o l c a n i c s were a l s o a n a l y s e d , so t h a t t h e c h e m i s t r y o f a l t e r a t i o n c o u l d be s t u d i e d ( C h a p t e r 4 . 4 ) . Ten samples o f t h e H a z e l t o n v o l c a n i c s a l s o were c o l l e c t e d from w i t h i n t h e a r e a of i n t e r e s t so t h a t t h e c h e m i s t r y of t h i s E a r l y J u r a s s i c c a l c - a l k a l i n e s u i t e c o u l d be compared t o t h a t o f t h e Toodoggone v o l c a n i c s . Samples were a n a l y s e d f o r 11 major e l e m e n t s . As w e l l , r e p r e s e n t a t i v e samples were a n a l y s e d f o r 12 t r a c e e l e m e n t s . M a j o r e l e m e n t a n a l y s e s were made by X - r a y f l u o r e s c e n c e u s i n g a P h i l i p s PW 1410 s p e c t r o m e t e r . T r a c e e l e m e n t a n a l y s e s by M in-En L a b o r a t o r i e s o f N o r t h V a n c o u v e r were done w i t h i n d u c t i v e l y c o u p l e d p l a s m a t e c h n i q u e s . Water and C 0 2 v a l u e s were c a l c u l a t e d u s i n g l o s s on i g n i t i o n a n a l y s e s as o u t l i n e d i n A p p e n d i x C-4. F e r r o u s i r o n was d e t e r m i n e d by wet 77 c h e m i c a l methods as d e s c r i b e d i n A p p e n d i x C-3. A n a l y t i c a l p r o c e d u r e s f o r major and t r a c e e l e m e n t s a r e d e s c r i b e d i n A p p e n d i x A and C. The c h e m i c a l d a t a a r e p r e s e n t e d i n A p p e n d i x A. 4 . 2 C l a s s i f i c a t i o n Toodoggone v o l c a n i c s c a n be c l a s s i f i e d u s i n g t h e scheme of I r v i n g and B a r a g a r ( 1 9 7 1 ) . F i g u r e 4-1, a p l o t of n o r m a t i v e Qz-01-Ne a l l o w s d i s c r i m i n a t i o n between a l k a l i n e and s u b a l k a l i n e t r e n d s w i t h i n v o l c a n i c r o c k s . Most a n a l y s e s g r o u p on t h e r i g h t s i d e o f t h e t e r n a r y d i a g r a m i n d i c a t i n g t h e s u b a l k a l i n e n a t u r e of t h e Toodoggone v o l c a n i c s . Two s a mples (1130 and 1134) t h a t p l o t i n t h e a l k a l i n e f i e l d were c o l l e c t e d from a s i n g l e v o l c a n i c f l o w w h i c h o n l y c r o p s out i n Moosehorn C r e e k i n t h e n o r t h w e s t p o r t i o n of t h e s t u d y - a r e a ( P l a t e s I and I I ) . T h i s u n i t i s i n t e r p r e t e d as b e i n g t h e p r o d u c t o f a s m a l l , i s o l a t e d , more a l k a l i n e magma chamber, s e p a r a t e d from t h e chambers w h i c h gave r i s e t o t h e s u b a l k a l i n e v o l c a n i c s o f t h e Toodoggone s u i t e . The c a l c - a l k a l i n e n a t u r e of t h e v o l c a n i c s i s c l e a r l y d e p i c t e d on an AFM d i a g r a m ( F i g u r e 4 - 2 ) . The samples a n a l y s e d showed a r a n g e of i n t e n s i t y of h y d r o t h e r m a l a l t e r a t i o n . S p i t z e t a l . , ( l 9 7 5 ) a r g u e s , however, t h a t b o t h t h e AFM and Qz-Ol-Ne t e r n a r y d i a g r a m s a r e r e l i a b l e f o r c h a r a c t e r i z i n g t h e c a l c - a l k a l i n e n a t u r e o f v o l c a n i c s u i t e s , e ven where t h e o r i g i n a l c h e m i s t r y i s somewhat m o d i f i e d by t h e e f f e c t s o f low g r a d e m e t a s o m a t i s m . 01 Ne Ab Qz FIGURE 4-1: Ol-Ne-Q b a s a l t r i a n g l e o f the Cpx-01-Ne-Q t e t r a h e d r o n p r o j e c t e d from Cpx. L i n e s s e p a r a t i n g f i e l d s o f a l k a l i n e and s u b a l k a l i h e r o c k s ;are a f t e r I r v i n e and B a r a g a r (1971) . Symbols used a r e as f o l l o w s : • Toodoggone a n d e s i t e , 4) Toodoggone d a c i t e , T r h y o l i t e , • Toodoggone t r a c h y t e , o H a z e l t o n a n d e s i t e . F A M FIGURE 4-2: AFM diagram xvith c u r v e s e p a r a t i n g f x e l d s o f t h o l e i i t i c and c a l c - a l k a l i n e r o c k s ( I r v i n e and B a r a g a r , 1971). A = Na„0 + K~0, F = FeO + 0 .8998 F e ^ , M = MgO. A l l v a l u e s a r e e x p r e s s e d i n w e i g h t p e r c e n t . Symbols a r e as i n F i g u r e 4-1. 80 On a n o r m a t i v e An-Or-Ab diagram a f t e r I r v i n e and Baragar (1971), the Toodoggone v o l c a n i c s a r e average i n c o m p o s i t i o n , a l t h o u g h some a n d e s i t e s p l o t i n the K - r i c h and N a - r i c h f i e l d s ( F i g u r e 4-3). The enrichment i n both p o t a s s i u m and sodium of some members of the Toodoggone s u i t e i s p r o b a b l y the r e s u l t of p o t a s s i u m metasomatism which accompanies some forms of h y d r o t h e r m a l a l t e r a t i o n (Chapter 4.4). A l t e r n a t i v e l y , the o b s e r v e d enrichment c o u l d p o s s i b l y have r e s u l t e d from a l k a l i - i o n exchange between the r o c k s and aqueous-pore f l u i d s d u r i n g p r i m a r y c o o l i n g and d e v i t r i f i c a t i o n ( S c o t t , 1971). In F i g u r e 4-4 the Toodoggone s u i t e p l o t s i n the o r o g e n i c f i e l d of the M g O - F e O ( t o t a l ) - A l 2 0 3 diagram of Pearce e t a l . , ( l 9 7 7 ) . F i g u r e 4-5 i s a p l o t of n o r m a t i v e p l a g i o c l a s e c o n t e n t v e r s u s n o r m a t i v e c o l o u r index showing the d i v i d i n g l i n e s between the f i e l d s b a s a l t , a n d e s i t e , d a c i t e and r h y o l i t e as d e l i n e a t e d by I r v i n e and Baragar (1971). Toodoggone v o l c a n i c r o c k s c l a s s i f y as a n d e s i t e s and d a c i t e s . The t h r e e samples t h a t p l o t i n the r h y o l i t e f i e l d (samples 1128, 1091 and 1022), r e p r e s e n t l a t e s t a g e dykes t h a t c u t the more i n t e r m e d i a t e c o m p o s i t i o n v o l c a n i c p i l e . The two samples t h a t a r e c a t e g o r i z e d as a l k a l i c ( F i g u r e 4-1) are not shown on t h i s f i g u r e . Most v o l c a n i c f l o w s and t u f f s a r e a n d e s i t i c , whereas the change i n c o m p o s i t i o n t o more d a c i t i c v o l c a n i s m i s accompanied by a change i n the mode of e r u p t i o n from a non e x p l o s i v e type t o t h a t of a nuee a r d e n t e s t y l e . I t i s w e l l known t h a t most major elements a r e m o b i l e d u r i n g low grade metasomatism ( G a r c i a , 1978; Condie et a l . , FIGURE 4-3: Normative An-Ab-Or t e r n a r y diagram w i t h c u r v e s s e p a r a t i n g t h e K - r i c h , average, and s o d i c f i e l d s ( a f t e r I r v i n e and B a r a g a r , 1971). Symbols a r e as i n F i g u r e 4-1. 82 FeO MgO AI203 FIGURE 4-4: F e O ( t o t a l ) - M g O - A l ,,0^ diagram w i t h t h e l i n e s s e p a r a t i n g t h e t e c t o n i c e nvironments o f f o r m a t i o n ( a f t e r Pearce e t a l . , 1977). Symbols a r e as i n F i g u r e 4-1. An/(An+Ab) FIGURE" 4-5 : Normative p l a g i o c l a s e (10 0An/(An + Ab + 5/3Ne) v e r s u s n o r m a t i v e c o l o u r i n d e x ( 01 + Opx + Cpx + I l m + Hm), w i t h t h e c l a s s i f i c a t i o n l i n e s o f I r v i n e and B a r a g a r (1971). Symbols a r e as i n F i g u r e 4-1. 84 1977). In o r d e r t o v e r i f y the c l a s s i f i c a t i o n of the Toodoggone v o l c a n i c s as a n d e s i t e s and d a c i t e s a p l o t e m p h a s i z i n g immobile elements i s needed. Under the e f f e c t s of low grade metasomatism, Zr and T i seem t o be immobile and t h u s a r e u s e f u l f o r c l a s s i f i c a t i o n purposes (Winchester and F l o y d , 1976; F i n l o w - B a t e s , 1981). F i g u r e 4-6 i s a p l o t of weight p e r c e n t S i 0 2 v e r s u s Z r / T i 0 2 and shows the c l a s s i f i c a t i o n l i n e s of W i n c h e s t e r and F l o y d (1976). F l o y d and W i n c h e s t e r (1978) s t a t e t h a t S i 0 2 i s e a s i l y m o b i l i z e d d u r i n g low grade metasomatism, and t h a t c a r e must be o b s e r v e d when u s i n g t h i s type of d i s c r i m i n a t i o n diagram. As s i l i c i f i c a t i o n i s an e x t r e m e l y abundant a l t e r a t i o n s t y l e i n the s t u d y - a r e a , c a r e was t a k e n t o ensure t h a t o n l y u n s i l i c i f i e d samples were used f o r t h i s p l o t . A c c o r d i n g t o t h i s scheme, samples a r e d o m i n a n t l y a n d e s i t e s or d a c i t e s . Thus, c l a s s i f i c a t i o n by the scheme of I r v i n e and Baragar (1971) i s c o r r o b o r a t e d . I t thus appears t h a t c l a s s i f i c a t i o n of the Toodoggone v o l c a n i c s on the b a s i s of major element c h e m i c a l a n a l y s e s i s v a l i d , and a d e q u a t e l y r e p r e s e n t s t h e i r i n i t i a l c h e m i s t r y a t the time of f o r m a t i o n . 4.3 V a r i a t i o n Diagrams U n a l t e r e d members of the Toodoggone v o l c a n i c s d i s p l a y a range of s i l i c a c o n t e n t from 56 t o 66 weight p e r c e n t . The abundance of a n d e s i t e s w i t h i n the s u i t e i s i n d i c a t e d by a c o m p o s i t i o n a l g r o u p i n g of v a l u e s between 56 and 62 p e r c e n t , the range of s i l i c a c o n t e n t s f o r average o r o g e n i c a n d e s i t e s 85 4 5 H i i - r-0 . 0 1 0.1 1.0 Z r / T i 0 2 4 0 FIGURE 4-6: Zr/TiO„ v e r s u s SiO p l o t w i t h l i n e s s e p a r a t i n g f i e l d s a f t e r W i n c h e s t e r and F l o y d (1976). Symbols a r e as i n F i g u r e 4-1. 86 ( T a y l o r , 1969). C h e m i c a l v a r i a t i o n s and r e l a t i v e e l e m e n t m o b i l i t y w i t h i n t h e v o l c a n i c s a r e d e p i c t e d i n F i g u r e s 4-7 t o 4-11. E l e m e n t s t h a t show d e p l e t i o n w i t h r e s p e c t t o i n c r e a s i n g s i l i c a c o n t e n t a r e CaO, P 2 0 5 , T i 0 2 , F e O ( T o t a l ) , A l 2 0 3 , and maybe V and Z r . O n l y K 2 0 i s c h a r a c t e r i z e d by an e n r i c h m e n t i n r e l a t i o n t o s i l i c a c o n t e n t s ( F i g u r e 4 - 7 ) . B o t h MnO and Ba, and p o s s i b l y Nb have a r e l a t i v e l y c o n s t a n t v a l u e . Even t h o u g h t h e samples c o l l e c t e d f o r a n a l y s i s were as f r e s h as p o s s i b l e , e l e m e n t m o b i l i t y d u r i n g low g r a d e m e t asomatism i s p r o b a b l y i n d i c a t e d by t h e s e v e r e s c a t t e r o f p o i n t s i n t h e N a 2 0 , MgO, C r , N i , Th, S r , Rb, and Nb v a r i a t i o n d i a g r a m s . The e l e m e n t s t h a t a p p e a r most i m m o b i l e under t h e i n f l u e n c e of m e t a s o m a t i c p r o c e s s e s a r e T i 0 2 , Zr and t o a l e s s e r e x t e n t A 1 2 0 3 and P 2 0 5 . 4.4 C h e m i s t r y of A l t e r a t i o n In o r d e r t o s t u d y t h e e f f e c t s o f v a r i o u s forms o f h y d r o t h e r m a l a l t e r a t i o n on t h e c h e m i s t r y of t h e Toodoggone v o l c a n i c s , a l t e r e d s amples were a n a l y s e d and t h e r e s u l t s a r e p l o t t e d i n F i g u r e s 4-12 and 4-13. The f o u r m a j o r a l t e r a t i o n t y p e s e f f e c t i n g t h e a n d e s i t e s i n t h e s t u d y - a r e a a r e a r g i l l i c , p o t a s s i c , s i l i c i c and p r o p y l i t i c f a c i e s ( C h a p t e r 3 . 3 ) . As no u n a l t e r e d r o c k s were a v a i l a b l e f o r a n a l y s i s i n t h e Toodoggone R i v e r a r e a , c h a n g e s i n c h e m i c a l c o m p o s i t i o n w i l l be r e l a t i v e t o t h e p r o p y l i t i c a l l y a l t e r e d a n d e s i t e s as t h i s form of a l t e r a t i o n i s s a i d t o c a u s e o n l y s l i g h t c h a n g e s i n c h e m i c a l c o m p o s i t i o n ( W h i t e b r e a d , 1976). S i g n i f i c a n t 87 o CM 6 -4 -2 -0 50 55 60 %Si02 65 To FIGURE 4-7: Harke'r v a r i a t i o n diagrams f o r t h e Toodoggone v o l c a n i c s . Oxide v a l u e s a r e i n w e i g h t p e r c e n t . Symbols a r e as i n F i g u r e 4-1. 88 _ 12-CO O 8-\— O CD ii • 4-o-6-o 4-CO <£ 2-0-19-CO O CVJ 17-< 15-13-o CO O a? 12-8-4 0 FIGURE 4-8: H a r k e r v a r i a t i o n diagrams f o r t h e Toodoggone v o l c a n i c s . Oxide v a l u e s are i n w e i g h t p e r c e n t . Symbols a r e as i n F i g u r e 4-1. 89 0.3-1 io O 0.2 i CM & O.H E a a k_ O 60-40-20-0 —•f* 1 1 — * E a a 12 8H 4 0 • • • E a a 30-20-10-0 50 — i — 55 60 %Si02 65 70 FIGURE 4-9: H a r k e r v a r i a t i o n diagrams f o r the Toodoggone v o l c a n i c s . Oxide v a l u e s a r e i n w e i g h t p e r c e n t . Trace elements a r e i n p a r t s per m i l l i o n , Symbols a r e as i n F i g u r e 4-1. 90 • E Q. a E a a CO 150 100 50 0 600 400 200 0 300 200 100 0 ~ 3 0 0 0 -E a 2 0 0 0 1 CO m 1 0 0 0 -E a a X) %Si02 FIGURE 4-10: H a r k e r v a r i a t i o n diagrams f o r the Toodoggone v o l c a n i c s . Values- a r e e x p r e s s e d i n p a r t s p e r m i l l i o n . Symbols a r e as i n F i g u r e 4-1. 91 E a a 30 20 10 0 E 150 -a 100 -Q. k. N 50 -0 -60 %Si02 FIGURE 4-11: H a r k e r v a r i a t i o n diagrams f o r t h e Toodoggone v o l c a n i c s . V a l u e s a r e e x p r e s s e d i n p a r t s p e r m i l l i o n . Symbols a r e as i n F i g u r e 4-1. Si02 T i02 AI203 F e 2 0 3 H20 FIGURE 4-12: A l t e r a t i o n v e r s u s major element c h e m i s t r y v a r i a t i o n diagram. Oxides a re e x p r e s s e d i n w e i g h t p e r c e n t . 1. Data a r e from t h i s s t u d y and from Great Western Petroleum. C o r p o r a t i o n r e p o r t s . FIGURE 4-13: A l t e r a t i o n v e r s u s t r a c e element c h e m i s t r y v a r i a t i o n diagram. Trace elements ar e e x p r e s s e d i n p a r t s p e r m i l l i o n , w i t h the e x c e p t i o n o f Au which i s i n p a r t s p e r b i l l i o n . 1. Data a r e from t h i s s t u d y and Great Western P e t r o l e u m C o r p o r a t i o n r e p o r t s . 2. Data a r e from G r e a t Western P e t r o l e u m C o r p o r a t i o n r e p o r t s 94 c h a n g e s i n t h e amount of C 0 2 m i g h t be e x p e c t e d as d e g r e e of p r o p y l i t i z a t i o n i n c r e a s e s , and hence c h a n g e s i n t h e amount of C 0 2 d u r i n g o t h e r forms o f a l t e r a t i o n a r e o n l y q u a l i t a t i v e . F i g u r e s 4-12 and 4-13 were c o n s t r u c t e d by t a k i n g t h e a v e r a g e o f two o r more a n a l y s e s f o r e a c h a l t e r a t i o n s t y l e , a s s u m i n g c o n s t a n t volume. As shown i n F i g u r e 4-12 a l l major e l e m e n t s e x h i b i t s i g n i f i c a n t m o b i l i t y d u r i n g h y d r o t h e r m a l a l t e r a t i o n w i t h t h e e x c e p t i o n of T i 0 2 w h i c h i s r e l a t i v e l y i m m o b i l e . In t h e p o t a s s i c zone, t h e most p r o n o u n c e d c h e m i c a l c h a n g e s a r e t h e i n c r e a s e o f CaO and K 2 0 . The h i g h e r K 2 0 r e s u l t s i n s e c o n d a r y o r t h o c l a s e , a d u l a r i a , and b i o t i t e o c c u r i n g w i t h i n t h i s z o n e . The e n r i c h e d CaO i s r e p r e s e n t e d by i n c r e a s e d modal c a r b o n a t e w i t h i n p o t a s s i c a l l y a l t e r e d a n d e s i t e s . S i 1 i c i f i c a t i o n a l m o s t c o m p l e t e l y o b l i t e r a t e s t h e o r i g i n a l c h e m i s t r y of t h e r o c k s w i t h a l l m a j o r e l e m e n t s d e c r e a s i n g s h a r p l y w i t h t h e e x c e p t i o n of T i 0 2 , MnO and C 0 2 w h i c h r e m a i n e s s e n t i a l l y u nchanged. M i l k y w h i t e q u a r t z c o m p r i s e s up t o 90 p e r c e n t of t h e s e z o n e s , as i s r e f l e c t e d i n t h e h i g h S i 0 2 c o n t e n t ( F i g u r e 4-12). A r g i l l i c a l t e r a t i o n i s c h e m i c a l l y c h a r a c t e r i z e d by a d e c r e a s e i n FeO, F e 2 0 3 , MgO, CaO, P 2 0 5 , C 0 2 and an i n c r e a s e i n H 2 0 . W i t h i n t h i s zone p l a g i o c l a s e and t h e f e r r o m a g n e s i u m m i n e r a l s a r e b r o k e n down r e s u l t i n g i n t h e l o s s o f MgO, FeO, F e 2 0 3 and CaO ( P a r k and M a c D i a r m i d , 1975). The amount of N a 2 0 r e m a i n s unchanged r e l a t i v e t o t h e p r o p y l i t i c zone p o s s i b l y i n d i c a t i n g t h e p r e s e n c e of s m a l l amounts o f a l u n i t e . No d i s t i n c t i o n i s made between i n t e r m e d i a t e and 95 advanced a r g i l l i c a l t e r a t i o n i n t h i s study, as secondary quartz and a l u n i t e due not occur i n s p a t i a l l y d i s t i n c t zones w i t h i n a r g i l l i z e d v o l c a n i c r o c k s . The i n c r e a s e i n H 20 w i t h i n t h i s zone i s t y p i c a l of a r g i l l i c . a l t e r a t i o n and shows the importance of h y d r o l y t i c decomposition of s i l i c a t e s i n hydrothermal processes. H y d r o l y t i c decomposition r e s u l t s i n the removal of Ca , Mg , Na , and K ions from s i l i c a t e s , which are then r e p l a c e d by an e q u i v a l e n t number of hydrogen ions (Hemley and Jones, 1964). As was seen with the major elements, most t r a c e elements analysed with the e x c e p t i o n of Zr show a high degree of m o b i l i t y i n response to v a r y i n g i n t e n s i t i e s of hydrothermal a l t e r a t i o n . The most pronounced chemical changes accompany s i l i c i f i c a t i o n (Figure 4-13). Within t h i s a l t e r a t i o n f a c i e s Au, Ag, Cu, Pb and Zn are a l l e n r i c h e d as p r e c i o u s and base metal m i n e r a l i z a t i o n i n v a r i b l y accompanies s i 1 i c i f i c a t i o n (Chapter 5). As w e l l , Ba shows a marked in c r e a s e w i t h i n t h i s zone with t h i s enrichment being r e f l e c t e d by the presence of b a r i t e , most of which i s a s s o c i a t e d with economic m i n e r a l i z a t i o n . S i l i c i f i c a t i o n i s a l s o c h a r a c t e r i z e d by a d e p l e t i o n i n N i , Cr, V, Rb, Zr, Th and a s l i g h t enrichment i n Sr. Other t r a c e elements that may be e n r i c h e d i n s i l i c i f i e d zones and thus prove u s e f u l i n geochemically d e t e c t i n g s i l i c i f i c a t i o n and m i n e r a l i z a t i o n i n c l u d e : As, Hg, Sb, T l and F (Peter, 1983; S c h r o e t e r , 1982) . In zones of p o t a s s i c a l t e r a t i o n the most s i g n i f i c a n t t r a c e element v a r i a t i o n i s an i n c r e a s e i n N i , Cr and V. 96 T h e s e e l e m e n t s r e a d i l y r e p l a c e Mg and Fe w i t h i n m a f i c m i n e r a l s and t h u s may be i n c o r p o r a t e d w i t h i n s e c o n d a r y b i o t i t e f o r m e d d u r i n g p o t a s s i u m metasomatism. P o t a s s i c a l l y a l t e r e d v o l c a n i c s a l s o d i s p l a y a s l i g h t i n c r e a s e i n Au, Ag, Cu, Pb and Zn v a l u e s , p o s s i b l y a s a r e s u l t o f t h e c l o s e p r o x i m i t y of t h i s form of a l t e r a t i o n t o m i n e r a l i z e d z o n e s ( F i g u r e 3 - 4 ) . A r g i l l i c a l t e r a t i o n i s c h a r a c t e r i z e d by e n r i c h m e n t i n Sr and t o a l e s s e r d e g r e e Nb. S t r o n t i u m i s g e n e r a l l y e n r i c h e d w i t h i n t h e p o t a s s i c zone a l o n g w i t h K•and Ca. However, O l a d e e t a l . , (1975) s u g g e s t s t h a t S r a n o m a l i e s may d e v e l o p i n a d j a c e n t p h y l l i c and a r g i l l i c z o n e s when p o t a s s i c a l l y a l t e r e d r e g i o n s a r e r e l a t i v e l y b a r r e n of m i n e r a l i z a t i o n , a s i s t h e c a s e i n Toodoggone R i v e r d e p o s i t s . The s o u r c e of t h e e n h a n c e d Sr i s u n c e r t a i n , a l t h o u g h i t may r e p l a c e p o t a s s i u m i n a l u n i t e o r be i n c o r p o r a t e d w i t h i n an u n d e t e c t e d Sr s u l p h a t e s u c h a s c e l e s t i t e . M e t a l s s u c h as Au, Ag, Cu, Pb and Zn a r e n o t e n h a n c e d w i t h i n t h e a r g i l l i z e d v o l c a n i c s and w i l l be of l i t t l e use i n d e t e c t i n g ' b l i n d ' o r e b o d i e s b e n e a t h l e a c h e d c a p z o n e s . I t s h o u l d be m e n t i o n e d h e r e t h a t f o r a more q u a n t i t a t i v e a n a l y s i s o f a l t e r a t i o n c h e m i s t r y , more t h a n two a n a l y s e s s h o u l d be p e r f o r m e d f o r e a c h a l t e r a t i o n s t y l e . 4.5 M e s o z o i c V o l c a n i c S u i t e s i n t h e C a n a d i a n C o r d i l l e r a R ocks o f t h e Toodoggone v o l c a n i c s a r e c h e m i c a l l y s i m i l a r t o o t h e r E a r l y J u r a s s i c v o l c a n i c s u i t e s i n t h e C a n a d i a n C o r d i l l e r a i n t h a t t h e y show a c a l c - a l k a l i n e 97 a f f i n i t y and have a ra n g e of c o m p o s i t i o n s from a n d e s i t e t o d a c i t e ( T a b l e 4 - 1 ) . E a r l y J u r a s s i c v o l c a n i c s of t h e Yakoun F o r m a t i o n , R o s s l a n d F o r m a t i o n and Bonanza V o l c a n i c s a r e c h e m i c a l l y a n a l o g o u s t o t h e Toodoggone v o l c a n i c s a l t h o u g h t h e f o r m e r s u i t e s t e n d t o have more a l k a l i n e c h a r a c t e r s and more b a s i c c o m p o s i t i o n s ( S o u t h e r , 1977). Of s p e c i a l i n t e r e s t a r e t h e E a r l y t o M i d d l e J u r a s s i c H a z e l t o n v o l c a n i c s w h i c h c r o p o u t w i t h i n t h e s t u d y - a r e a . H a z e l t o n r o c k s a r e c h e m i c a l l y i n d i s t i n g u i s h a b l e from t h e Toodoggone v o l c a n i c s ( F i g u r e s 4-1 t o 4-6), a l t h o u g h no d a c i t i c H a z e l t o n r o c k s a r e f o u n d i n t h e s t u d y - a r e a . As d e s c r i b e d by T i p p e r and R i c h a r d s ( 1 9 7 6 ) , t h e H a z e l t o n v o l c a n i c s u i t e r a n g e s i n c o m p o s i t i o n from b a s a l t t o r h y o l i t e and has b o t h t h o l e i i t i c and c a l c - a l k a l i n e t r e n d s , d e p e n d i n g on s t r a t i g r a p h i c l o c a t i o n . W i t h i n t h e Toodoggone R i v e r a r e a Toodoggone v o l c a n i c s a r e s i m i l a r , b o t h c h e m i c a l l y and t e x t u r a l l y , t o H a z e l t o n v o l c a n i c s w i t h t h e Toodoggone r o c k s p r o b a b l y b e i n g c o r r e l a t i v e w i t h t h e S m i t h e r s F o r m a t i o n o f t h e H a z e l t o n G roup. L a t e T r i a s s i c s u i t e s s u c h as t h e T a k l a , N i c o l a and Karmutsen Groups d i f f e r c h e m i c a l l y from t h e E a r l y J u r a s s i c Toodoggone v o l c a n i c s i n t h a t t h e T r i a s s i c G r o u p s have m a i n l y t h o l e i i t i c a f f i n i t i e s , a l k a l i n e c h a r a c t e r s , and a g r e a t e r p r e p o n d e r a n c e of b a s a l t s t h a n i n t e r m e d i a t e t o a c i d v o l c a n i c s ( T a b l e 4 - 1 ) . In summary, t h e Toodoggone v o l c a n i c s a r e c h e m i c a l l y s i m i l a r t o o t h e r E a r l y t o M i d d l e J u r a s s i c v o l c a n i c s u i t e s i n t h e C a n a d i a n C o r d i l l e r a , and a r e c h e m i c a l l y s i m i l a r t o TABLE 4-1 Mesozoic Volcanism i n the Canadian C o r d i l l e r a Volcanic Suite Toodoggone Volcanics Hazelton Group Yakoun Formation" 4 Rossland Formation Bonanza Volcanics"* Takla Group Ni c o l a Group Age Early to Middle Jurassic E a r l y to Middle Jurassic Early to Middle Jurassic Early Jurassic Early Jurassic Late T r i a s s i c Late T r i a s s i c General Chemistry c a l c - a l k a l i n e t h o l e i i t i c to c a l c - a l k a l i n e c a l c - a l k a l i n e c a l c - a l k a l i n e c a l c - a l k a l i n e t h o l e i i t i c c a l c - a l k a l i n e to t h o l e i i t i c Major L i t h o l o g i e s andesite, dacite andesite, dacite, r h y o l i t e , basalt andesite basalts, andesites, dacites basalt, andesite, . rhyodacite ba s a l t s , dacites, andesites ba s a l t s , andesites, dacites Karmutsen Group Late T r i a s s i c t h o l e i i t i c basalts 1. Data are from t h i s study 2. Data are from t h i s study and Tipper et_ a l . , (1976) 3. Data are from Southerland Brown (1954) 4. Data are from L i t t l e (1960) 5. Data are from Muller et a l . , (1974) 6. Monger (1977) 7. Preto (1977) 8. Muller (1971) 99 c a l c - a l k a l i n e o r o g e n i c v o l c a n i c s u i t e s t h r o u g h o u t t h e w o r l d ( G u n n , l 9 7 4 ; T a y l o r , 1 969 ; J a k e s and W h i t e , 1972) 100 CHAPTER 5 ECONOMIC GEOLOGY 5.1 I n t r o d u c t i o n The Toodoggone R i v e r a r e a i s t h e newest p r o d u c e r of p r e c i o u s m e t a l s i n t h e C a n a d i a n C o r d i l l e r a . W i t h i n t h e a r e a , E a r l y J u r a s s i c Toodoggone and H a z e l t o n as w e l l a s L a t e T r i a s s i c T a k l a r o c k s a c t as h o s t t o e p i t h e r m a l v e i n g o l d and s i l v e r m i n e r a l i z a t i o n . R e p e a t e d n o r m a l f a u l t i n g d u r i n g t h e J u r a s s i c p r o v i d e d t h e p l u m b i n g a l o n g w h i c h m i n e r a l i z i n g s o l u t i o n s m i g r a t e d ( S c h r o e t e r , 1981). A sample of a l u n i t e f r o m a v e i n has y i e l d e d a K-Ar age o f 190+7 Ma, i n d i c a t i n g t h a t t h e major p u l s e of m i n e r a l i z a t i o n o c c u r e d d u r i n g t h e E a r l y J u r a s s i c . S i l i c i f i e d z o n e s r a n g e i n w i d t h from a few m i l l i m e t e r s t o t e n s o f m e t r e s , and g e n e r a l l y p i n c h and s w e l l a l o n g t h e i r l e n g t h . H o r s e t a i l i n g and b i f u r c a t i o n o f t h e s e m i n e r a l i z e d z o n e s a r e common. M i n e r a l i z a t i o n does n o t a p p e a r t o be i n f l u e n c e d by l i t h o l o g y , a l t h o u g h v e i n s t e n d t o be of g r e a t e r abundance i n t h e more competent f l o w s t h a n i n t h e t u f f s . The main o r e m i n e r a l s i d e n t i f i e d i n t h e d e p o s i t s a r e a c a n t h i t e , g o l d , s i l v e r a nd e l e c t r u m w i t h m i n o r amounts o f c h a l c o p y r i t e , g a l e n a , s p h a l e r i t e , p o l y b a s i t e and b o r n i t e . The o v e r a l l s i l v e r t o g o l d r a t i o i s 20:1. Gangue m i n e r a l s i n c l u d e , i n o r d e r of ab u n d a n c e : a m e t h y s t i n e , c h a l c e d o n i c and w h i t e q u a r t z , c a l c i t e , p y r i t e , s p e c u l a r h e m a t i t e , a d u l a r i a and manganese o x i d e w i t h l e s s e r amounts o f b a r i t e , f l u o r i t e , 101 s i d e r i t e and c h l o r i t e . G e n e r a l l y t h e r e i s a d i s t i n c t m e t a l z o n a t i o n w i t h i n t h e s e d e p o s i t s ; base m e t a l s b e i n g d e p o s i t e d e a r l y and hence a t g r e a t e r d e p t h s , w h i l e p r e c i o u s m e t a l s t e n d t o r e m a i n i n s o l u t i o n l o n g e r and o c c u r a t h i g h e r e l e v a t i o n s w i t h i n t h e h y d r o t h e r m a l s y s t e m . T y p i c a l m i n e r a l i z e d z o n e s a r e s t o c k w o r k s o r v e i n - f i l l i n g s w i t h as many as f i v e o r s i x s t a g e s of b r e c c i a t i o n and s i l i c i f i c a t i o n . V e i n t e x t u r e s a r e t y p i c a l of d e p o s i t s formed by open s p a c e f i l l i n g and i n c l u d e : s y m m e t r i c a l b a n d i n g , d r u s y c o a t i n g s and c r u s t i f o r m , c o l l o f o r m and comb t e x t u r e s . A number of s o l f a t a r i c a l l y a l t e r e d , low pH z o n e s o c c u r i n t h e r e g i o n and a p p e a r t o r e p r e s e n t t h e uppermost l e v e l s o f t h e h y d r o t h e r m a l s y s t e m (Buchanan, 1981). T h e s e b l e a c h e d , o f t e n g o s s a n o u s r e g i o n s g e n e r a l l y o c c u r i n p e r m e a b l e a n d e s i t e t u f f s r a t h e r t h a n i n f l o w s w i t h t h e m i n e r a l s k a o l i n i t e , a l u n i t e , m o n t m o r i l i o n i t e , i l l i t e and d i c k i t e b e i n g most common (XRD a n a l y s e s , A p p e n d i x E ) . E p i s o d i c b o i l i n g a p p e a r s t o be r e s p o n s i b l e f o r t h i s form of a l t e r a t i o n , as w e l l as f o r t h e d i s t r i b u t i o n and z o n a t i o n of p r e c i o u s and base m e t a l s ( B e r g e r and Eimon, 1983). 5.2 P r o s p e c t s and D e p o s i t s E i g h t m i n e r a l d e p o s i t s o c c u r w i t h i n t h e s t u d y - a r e a ( P l a t e I) and w i l l be d i s c u s s e d s e p a r a t e l y . Of t h e e i g h t , t h e Moosehorn and Mt G r a v e s p r o s p e c t s were c h o s e n f o r f l u i d i n c l u s i o n s t u d i e s and w i l l t h e r e f o r e be d i s c u s s e d i n g r e a t e r d e t a i 1 . 102 A l l d e p o s i t s o c c u r i n E a r l y J u r a s s i c Toodoggone v o l c a n i c r o c k s , e x c e p t f o r t h e Baker mine w h i c h i s i n L a t e T r i a s s i c T a k l a v o l c a n i c s , and t h e Mt G r a v e s p r o s p e c t w h i c h o c c u r s i n H a z e l t o n v o l c a n i c s . Moosehorn Amethyst B r e c c i a Zone The Moosehorn Amethyst B r e c c i a zone i s b e i n g e x p l o r e d by G r e a t W e s t e r n P e t r o l e u m C o r p o r a t i o n . I t i s l o c a t e d i n t h e c a n y o n of Moosehorn C r e e k , a p p r o x i m a t e l y one km u p s t r e a m from t h e j u n c t i o n of t h e c r e e k w i t h t h e Toodoggone R i v e r . ( P l a t e I ) . V e i n m i n e r a l i z a t i o n o c c u r s a t t h e c o n t a c t between two t r a c h y t e f l o w s ( P l a t e 5-1), w i t h t h e b e s t e x p o s u r e s b e i n g i n t h e l o w e r p a r t of t h e 40 m w a l l s of t h e c a n y o n . A 2 5 - m - t h i c k s e q u e n c e of v a r i c o l o u r e d g r e y w a c k e s o v e r l i e s t h e f l o w s and i s u n m i n e r a l i z e d . The s c a r p - l i k e a p p e a r a n c e o f t h e Moosehorn C r e e k c a n y o n w a l l s and t h e a p p a r e n t o f f s e t of t h e g r e y w a c k e s may i n d i c a t e t h e p r e s e n c e of a n o r t h - s o u t h s t r i k i n g f a u l t , c o i n c i d e n t w i t h t h e c r e e k v a l l e y . F l u i d i n c l u s i o n e v i d e n c e s u g g e s t s t h a t t h e f a u l t h as n o r m a l throw and p o s t - d a t e s m i n e r a l i z a t i o n ( C h a p t e r 5.3) . The a m e t h y s t b r e c c i a zone has been t r a c e d o v e r a n o r t h - s o u t h l e n g t h o f 375 m and r a n g e s i n w i d t h from one t o f i v e m. I t s v e r t i c a l e x t e n t i s unknown, a s o n l y 10 m of v e i n i s e x p o s e d above t a l u s f r o m t h e c l i f f s . M i n e r a l i z a t i o n a p p e a r s t o d i p s t e e p l y e a s t w a r d a t a p p r o x i m a t e l y 75 d e g r e e s . G o l d , a s s a y i n g up t o 2.8 g p e r t onne o c c u r s s p o r a d i c a l l y a l o n g t h e r e c u r r e n t l y b r e c c i a t e d and s i l i c i f i e d v e i n and i s 103 a c c o m p a n i e d by s i l v e r v a l u e s o f up t o 56 g p e r t o n n e . The main o r e m i n e r a l s a r e a c a n t h i t e and n a t i v e s i l v e r , w h i c h g e n e r a l l y o c c u r as f i n e g r a i n e d d i s s e m i n a t i o n s i n q u a r t z . Gangue i s composed of a m e t h y s t i n e , w h i t e and c h a l c e d o n i c q u a r t z , c a l c i t e , s p e c u l a r h e m a t i t e , p y r i t e w i t h l e s s e r amounts o f c h l o r i t e , k a o l i n i t e , a l b i t e and a d u l a r i a ( S c h r o e t e r , 1981). T y p i c a l o p e n - s p a c e d f i l l i n g t e x t u r e s o c c u r w i t h i n t h e m i n e r a l i z e d zone ( C h a p t e r 5 . 1 ) . A m e t h y s t , o c c a s i o n a l l y o f s e m i - p r e c i o u s q u a l i t y o c c u r s i n g r e a t a b undance, but g e n e r a l l y does n o t c a r r y o r e g r a d e g o l d o r s i l v e r ; i t a p p e a r s t o p o s t d a t e o r e m i n e r a l d e p o s i t i o n . M i n o r amounts o f a m e t h y s t o c c u r s w i t h a c a n t h i t e i n o r e - s t a g e v e i n l e t s and c a n be d i s t i n g u i s h e d from l a t e s t a g e a m e t h y s t by t h e p r e s e n c e of a s s o c i a t e d c h a l c e d o n i c q u a r t z . The h i g h e s t g r a d e s a m p l e s were o b t a i n e d from f i n e l y banded, grey' c h a l c e d o n i c q u a r t z v e i n l e t s w i t h i n a h i g h l y f r a c t u r e d t r a c h y t e f l o w . S i l i c i f i c a t i o n i s t h e main e x p r e s s i o n o f h y d r o t h e r m a l a l t e r a t i o n , w i t h s l i g h t a r g i l l i c a l t e r a t i o n ( k a o l i n i t e p s e u d o m o r p h i n g f e l d s p a r c r y s t a l s ) i n t h e h a n g i n g w a l l t r a c h y t e s . V e i n s show w e l l d e v e l o p e d b a n d i n g w i t h . a c o n s i s t e n t p a r a g e n e t i c s e q u e n c e , and a t l e a s t f i v e s t a g e s of s i 1 i c i f i c a t i o n and b r e c c i a t i o n . Most s a m p l e s show one o r more o f t h e f o l l o w i n g m i n e r a l i z i n g and b r e c c i a t i o n s t a g e s : S t a g e 1 : D e p o s i t i o n of w h i t e , b u l l q u a r t z w h i c h was s u b s e q u e n t l y b r e c c i a t e d and cemented by q u a r t z and p y r i t e . S t a g e 2 : F i n e l y banded c h a l c e d o n i c q u a r t z w i t h minor p y r i t e d i s s e m i n a t i o n s ( P l a t e 5 - 2 ) . PLATE 5-1: B r e c c i a t e d and s i l i c i f i e d t r a c h y t e s o f the Moosehorn Amethyst B r e c c i a zone. Note flow c o n t a c t a t cent e r of photograph. The upper flow i s un m i n e r a l i z e d . C l i f f s are approximately 4 5 metres h i g h . PLATE 5-2: F i n e l y banded pre-ore c h a l c e d o n i c quartz from the Moosehorn propect. S c a l e i s i n m i l l i m e t r e s . 105 S t a g e 3, 4, 5, : C h a l c e d o n i c and minor a m e t h y s t i n e q u a r t z a c c o m p a n i e d by a c a n t h i t e , s i l v e r and p y r i t e . E a c h of t h e s t a g e s o f d e p o s i t i o n was f o l l o w e d by a p e r i o d of b r e c c i a t i o n and h e a l i n g by s i l i c i f i c a t i o n of p r e v i o u s l y f r a c t u r e d z o n e s . S t a g e 6 : D e p o s i t i o n o f a m e t h y s t a c c o m p a n i e d by s p e c u l a r h e m a t i t e , w h i t e q u a r t z and minor a c a n t h i t e ( P l a t e 5 -3), and was f o l l o w e d by a p e r i o d of b r e c c i a t i o n . S t a g e 7 : C a l c i t e , h e m a t i t e and manganese o x i d e i n f i l l i n g a l l r e m a i n i n g open s p a c e s w i t h i n t h e v e i n . S t a g e 8 : A number o f f u r t h e r e p i s o d e s of b r e c c i a t i o n f o l l o w e d s t a g e 7 d e p o s i t i o n and a r e r e p r e s e n t e d by a network of d r y f r a c t u r e s . The Moosehorn p r o s p e c t has not y e t been t e s t e d by d r i l l i n g . However, f l u i d i n c l u s i o n e v i d e n c e s u g g e s t s t h a t t h i s d e p o s i t may i n c r e a s e i n g r a d e and s i z e a t d e p t h ( C h a p t e r 5 . 4 ) . S i l v e r p o n d P r o s p e c t The S i l v e r p o n d p r o s p e c t i s c u r r e n t l y b e i n g e x p l o r e d by S t J o e Canada I n c . t h r o u g h an o p t i o n agreement w i t h G r e a t W e s t e r n P e t r o l e u m C o r p o r a t i o n . S i t u a t e d a p p r o x i m a t e l y f o u r km s o u t h of t h e Toodoggone R i v e r a l o n g t h e w e s t e r n m a r g i n o f t h e s t u d y - a r e a , i t i s l o c a t e d w i t h i n a s e q u e n c e of a n d e s i t i c f l o w s and p y r o c l a s t i c s ( P l a t e I ) . The beds g e n e r a l l y s t r i k e n o r t h - e a s t and have s h a l l o w d i p s r a n g i n g from 5 t o 20 d e g r e e s . S u s t u t Group c o n g l o m e r a t e s u n c o n f o r m a b l y o v e r l i e t h e v o l c a n i c s on t h e s o u t h w e s t m a r g i n of t h e p r o p e r t y . An a l t e r a t i o n z o n e , two km a c r o s s , c o v e r s much of t h e 106 P 1 - chalcedony P 2 - milky quartz P 3 - amethyst P 4 - milky quartz PS- acanthite and specular i te PLATE 5-3: Amethyst v e i n from t h e Moosehorn p r o s p e c t c o n t a i n i n g d i s s e m i n a t e d s p e c u l a r i t e , a c a n t h i t e and l i m o n i t e . 107 p r o p e r t y and i s marked by a g o s s a n of abundant g o e t h i t e , j a r o s i t e and h e m a t i t e ( P l a t e 5 - 4 ) . A l t e r a t i o n o c c u r s i n a r o u g h l y c i r c u l a r f a s h i o n , w i t h t h e c e n t r a l c o r e b e i n g marked by an i r r e g u l a r l y d i s t r i b u t e d i n t e r m e d i a t e and a d v a n c e d a r g i l l i c a l t e r a t i o n . A l t e r a t i o n g r a d e s o u t w a r d t o p r o p y l i t i c a l l y a l t e r e d r o c k s . S e c o n d a r y m i n e r a l s w i t h i n t h e i n t e r m e d i a t e t o a d v a n c e d a r g i l l i c a l l y a l t e r e d z o n e s i n c l u d e q u a r t z , a l u n i t e , k a o l i n i t e , m o n t m o r i l l o n i t e , d i c k i t e , i l l i t e , s e r i c i t e , and m i n o r amounts of b a r i t e , f l u o r i t e , l i m o n i t e and p y r i t e ( S c h r o e t e r , 1 9 8 1 ' a n d XRD a n a l y s e s , A p p e n d i x E ) . T h i s s t y l e and z o n i n g of h y d r o t h e r m a l a l t e r a t i o n i s t y p i c a l o f t h e low pH c a p z o n e s of e p i t h e r m a l s y s t e m s as d e s c r i b e d by Buchanan ( 1 9 8 1 ) , and G i l e s and N e l s o n ( 1 9 8 2 ) . A web of n o r m a l and s t r i k e s l i p f a u l t s t r a n s e c t t h e m i n e r a l i z e d a r e a , and g e n e r a l l y c o i n c i d e w i t h t h e more i n t e n s e l y a l t e r e d r e g i o n s . G o l d and s i l v e r a r e g e n e r a l l y a b s e n t f r o m t h e s e i n t e n s e l y a l t e r e d r e g i o n s o f t h e p r o p e r t y , w i t h p y r i t e and minor m a g n e t i t e b e i n g t h e o n l y v i s i b l e m e t a l l i c m i n e r a l s . G o l d v a l u e s w i t h i n t h e s i l i c i f i e d and a r g i l l i c a l l y a l t e r e d r o c k s a r e o n l y s l i g h t l y h i g h e r t h a n b a c k g r o u n d i n t e n s i t i e s , r a n g i n g f r o m 5 t o 60 p a r t s p e r b i l l i o n . S i l v e r g r a d e s a r e a l s o v e r y low, w i t h v a l u e s o f between 0.7 and 2.7 p a r t s p e r m i l l i o n b e i n g most common. The r i c h e s t m i n e r a l i z a t i o n on t h e p r o p e r t y i s l o c a t e d i n an e x p o s u r e on C l o u d C r e e k , two km s o u t h of t h e c o n s p i c u o u s g o s s a n z o n e . Here a p e r v a s i v e l y s i l i c i f i e d and b r e c c i a t e d t u f f h o r i z o n c o n t a i n s d i s s e m i n a t e d a c a n t h i t e , 108 t e t r a h e d r i t e and m i n o r e l e c t r u m . The zone i s 60 m l o n g , open a t b o t h e n d s , and has u n d e t e r m i n e d w i d t h and a t t i t u d e . G o l d and s i l v e r g r a d e s w i t h i n t h e s i l i c i f i e d r o c k s range up t o 8.5 g p e r t o n n e and 504 g p e r t onne r e s p e c t i v e l y . P e r i p h e r a l t o t h e s i l i c i f i e d z o ne, th e a n d e s i t e t u f f s a r e p r o p y l i t i c a l l y a l t e r e d and c o n t a i n minor p y r i t e and m a g n e t i t e . L a w y e r s Amethyst G o l d B r e c c i a (AGB) Zone The L a w y e r s Amethyst G o l d B r e c c i a zone owned by SEREM L t d . i n j o i n t v e n t u r e w i t h A g n i c o - E a g l e M i n e s L t d . , Sudbury C o n t a c t M i n e s L t d . and Kennco E x p l o r a t i o n s (Canada) L i m i t e d i s l o c a t e d s i x km s o u t h of Kodah Lake i n t h e w e s t - c e n t r a l p o r t i o n o f t h e s t u d y - a r e a ( P l a t e I ) . F a u l t and f r a c t u r e c o n t r o l l e d , s t e e p l y d i p p i n g s i l i c i f i e d and b r e c c i a t e d z o n e s l i e i n a s e q u e n c e of a n d e s i t e t u f f s and f l o w s ( P l a t e 5 - 5 ) . The n o r t h - s t r i k i n g m i n e r a l i z e d zone has a l e n g t h o f 610 m, r a n g e s i n w i d t h from 60 t o 75 m, and has a v e r t i c a l d e p t h of a b o u t 75 m ( S c h r o e t e r , 1983). Ore m i n e r a l s w i t h i n t h e s i l i c i f i e d and i n t e n s e l y v e i n e d zone i n c l u d e a c a n t h i t e , e l e c t r u m , g o l d and s i l v e r , w i t h l e s s e r amounts o f c h a l c o p y r i t e , s p h a l e r i t e , g a l e n a and c h a l c o c i t e . Gangue m i n e r a l s a r e s i m i l a r t o t h o s e o f t h e M oosehorn p r o s p e c t w i t h a m e t h y s t i n e t o w h i t e q u a r t z , c h l o r i t e , c a l c i t e , a d u l a r i a , h e m a t i t e and manganese o x i d e s t a i n i n g b e i n g most common. B o t h o r e and gangue m i n e r a l s e x h i b i t t y p i c a l open s p a c e f i l l i n g t e x t u r e s as d e s c r i b e d i n C h a p t e r 5.1. 109 PLATE 5-4: Prominent gossan c o i n c i d e n t w i t h a r g i l l i c a l l y a l t e r e d zone w i t h i n a n d e s i t e t u f f s on the S i l v e r p o n d p r o p e r t y . W i d t h o f photograph i s a p p r o x i m a t e l y 2 km. PLATE 5-5: Trenched main zone o f t h e Lawyers Amethyst Gold B r e c c i a zone. A d i t p o r t a l can be seen a t r i g h t edge o f photo. Width o f photo-graph i s a p p r o x i m a t e l y 1 km. 110 Grades of m i n e r a l i z a t i o n range c o n s i d e r a b l y over the l e n g t h of the zone, with one high grade s e c t i o n assaying 1554 g per tonne s i l v e r and 138 g per tonne g o l d over s i x m. Recent d r i l l i n g , both s u r f a c e and underground has o u t l i n e d ore r e s e r v e s t o t a l l i n g 510,648 tonnes averaging 201 g per tonne s i l v e r and 5.9 g per tonne gold (Schroeter, 1983). C l i f f Creek Prospect The C l i f f Creek prospect owned by the SEREM J o i n t Venture, i s l o c a t e d two km southwest of the Lawyers d e p o s i t in the w e s t - c e n t r a l p o r t i o n of the study-area. The g e o l o g i c a l s e t t i n g and m i n e r a l i z a t i o n are s i m i l a r to those of the Lawyers d e p o s i t . B r e c c i a t i o n and s i 1 i c i f i c a t i o n of the a n d e s i t e s has been t r a c e d f o r over 1000 m along a n o r t h w e s t e r l y t r e n d . Width of m i n e r a l i z a t i o n and v e r t i c a l extent have not been p r e c i s e l y d e f i n e d , but probably are i n the same order of magnitude as the Lawyers AGB zone. The most n o t i c a b l e d i f f e r e n c e between the Lawyers and C l i f f Creek d e p o s i t s i s the g r e a t e r abundance of amethyst and jasper i n the C l i f f Creek zone ( P l a t e 5-6). The Baker Mine The Baker g o l d / s i l v e r mine operated by Du Pont of Canada L t d came i n t o p r o d u c t i o n i s 1981 with r e s e r v e s t o t a l l i n g 90,718 tonnes of 25.5 g per tonne g o l d and 594 g per tonne s i l v e r ( S c hroeter, 1982). The mine i s c u r r e n t l y o p e r a t i n g at a rate of 100 tons per day, although a lack of ore w i l l probably cause the mine to c l o s e i n e a r l y 1984. I l l PLATE 5-6: Recurrently brecciated and s i l i c i f i e d andesite from the C l i f f Creek deposit showing fragments of amethystine, jasperoidal and milky quartz. 112 Seven q u a r t z v e i n s y s t e m s have been i d e n t i f i e d on t h e p r o p e r t y . These v e i n s o c c u r w i t h i n g a n d e s i t e and d a c i t e f l o w s , t u f f s and b r e c c i a s o f t h e T a k l a G roup ( B a r r , 1978), and t r e n d n o r t h e a s t and e a s t - s o u t h e a s t w i t h d i p s r a n g i n g from 80 d e g r e e s s o u t h e a s t t o 70 d e g r e e s n o r t h e a s t . The main v e i n ( V e i n A) i s p a r t of a q u a r t z v e i n s y s t e m c o n s i s t i n g of two c l o s e l y s p a c e d s u b p a r a l l e l v e i n s and a s s o c i a t e d s p l a y s ; i t h as been t r a c e d f o r o v e r 435 m w i t h v e i n w i d t h s r a n g i n g from 10 t o 75 m ( P e t e r , 1983). D r i l l i n g i n d i c a t e s t h a t i n d i v i d u a l v e i n s r a n g e i n w i d t h f rom 0.5 t o 9 m and have a v e r t i c a l d e p t h of up t o 150 m ( S c h r o e t e r , 1982). Numerous n o r t h w e s t e r l y t r e n d i n g c r o s s - c u t t i n g f a u l t s o f f s e t t h e v e i n s , w i t h d i s p l a c e m e n t s of up t o 1 5 m b e i n g common ( B a r r , 1978). The o t h e r s i x v e i n s y s t e m s have s i m i l a r a t t i t u d e s and s t r i k e l e n g t h s , a l t h o u g h t h e y t e n d t o have l e s s c o n s i s t e n t w i d t h s and l o w e r g r a d e s of m i n e r a l i z a t i o n . Ore m i n e r a l s o c c u r as d i s s e m i n a t i o n s w i t h i n b r e c c i a t e d and s i l i c i f i e d z o n e s and i n c l u d e e l e c t r u m , a c a n t h i t e , t e t r a h e d r i t e , g o l d , s i l v e r , s p h a l e r i t e , g a l e n a , c h a l c o p y r i t e , b o r n i t e , p o l y b a s i t e and minor p y r r h o t i t e ( B a r r , 1978; P e t e r , 1983). A l t e r a t i o n m i n e r a l s a s s o c i a t e d w i t h t h e o r e zones i n c l u d e q u a r t z , c h l o r i t e , c a l c i t e , p y r i t e , a n h y d r i t e , l a u m o n t i t e , and t r e m o l i t e ( P e t e r , 1983). O r e - s t a g e q u a r t z i s c h a r a c t e r i s t i c a l l y g r e y and g e n e r a l l y i s of t h e m i c r o c r y s t a l l i n e v a r i e t y . G o l d e n N e i g h b o u r P r o s p e c t The G o l d e n N e i g h b o u r p r o p e r t y owned by L a c a n a M i n i n g 113 C o r p o r a t i o n i s l o c a t e d a t t h e h e a d w a t e r s o f S a u n d e r s C r e e k a t t h e e a s t e r n m a r g i n o f t h e s t u d y - a r e a . A minimum o f s i x q u a r t z v e i n s o c c u r on t h e p r o p e r t y w i t h n o r t h w e s t s t r i k e s b e i n g most common. V e i n s range i n w i d t h f r o m l e s s t h a n one m t o t h r e e m and c o n t a i n c h a l c o p y r i t e , s p h a l e r i t e , g a l e n a , p y r i t e , m o l y b d e n i t e and minor s c h e e l i t e . G e o c h e m i c a l p r o s p e c t i n g has r e v e a l e d anomalous g o l d v a l u e s c o v e r i n g an a r e a of a p p r o x i m a t e l y two s q u a r e km, a l t h o u g h no p r e c i o u s m e t a l m i n e r a l i z a t i o n has been i d e n t i f i e d i n s u r f a c e t r e n c h e s . A n d e s i t e f l o w s and t u f f s i n t h e r e g i o n have been i n t e n s e l y a l t e r e d by h y d r o t h e r m a l s o l u t i o n s , w i t h i n t e r m e d i a t e a r g i l l i c and s i l i c i c a l t e r a t i o n c o v e r i n g much of t h e p r o p e r t y . Numerous n o r t h w e s t s t r i k i n g f a u l t s segment t h e r e g i o n and q u i t e commonly p a r a l l e l q u a r t z v e i n s . GWP 1 t o 10 P r o s p e c t The GWP 1 t o 10 p r o s p e c t owned by G r e a t W e s t e r n P e t r o l e u m C o r p o r a t i o n i s l o c a t e d t h r e e km e a s t of S a u n d e r s C r e e k i n t h e e a s t e r n p a r t o f t h e s t u d y - a r e a ( P l a t e I ) . Anomalous p r e c i o u s m e t a l c o n c e n t r a t i o n s of up t o 535 p a r t s p e r b i l l i o n g o l d and 3.5 p a r t s p e r m i l l i o n s i l v e r o c c u r o v e r a t h r e e s q u a r e km r e g i o n of s i l i c i f i e d and a r g i l l i c a l l y a l t e r e d a n d e s i t e f l o w s and t u f f s . The a r e a i s n e a r l y f l a t w i t h t h e s i l i c i f i e d z o n e s f o r m i n g r o u n d e d h i l l s , and t h e c l a y a l t e r e d z o n e s f o r m i n g d e p r e s s i o n s ( P l a t e 5-7). S i l i c i f i e d s t o c k w o r k z o n e s up t o 1000 m l o n g and 20 m wide s t r i k e n o r t h - n o r t h w e s t e r l y w i t h i n 114 PLATE 5-7: Gossanous s i l i c i f i e d zone f o r m i n g r i d g e on the GWP 1 t o 10 p r o p e r t y . Ridge i s a p p r o x i m a t e l y 1 km i n l e n g t h . 115 t h e g e n t l y d i p p i n g a n d e s i t e t u f f s and c o n t a i n a bundant p y r i t e , m a g n e t i t e and b a r i t e w i t h minor c h a l c o p y r i t e and m a l a c h i t e . A l t e r a t i o n m i n e r a l s a s s o c i a t e d w i t h t h e s u l f i d e m i n e r a l i z a t i o n i n c l u d e q u a r t z , c a l c i t e , h e m a t i t e , l i m o n i t e , k a o l i n i t e , m o n t m o r i l l o n i t e and i l l i t e (XRD a n a l y s e s , A p p e n d i x E ) . The a l t e r a t i o n , m i n e r a l o g y , and t e x t u r a l c h a r a c t e r i s t i c s of t h e v o l c a n i c r o c k s and m i n e r a l i z e d z o n e s of t h e GWP 1 t o 10 p r o p e r t y a r e s i m i l a r t o t h o s e on t h e S i l v e r p o n d p r o p e r t y , a l t h o u g h v i s i b l e s i l v e r or g o l d m i n e r a l i z a t i o n has not been documented i n t h e GWP 1 t o 10 z o n e . Mt. G r a v e s P r o s p e c t The Mt. G r a v e s p r o s p e c t owned by G r e a t W e s t e r n P e t r o l e u m C o r p o r a t i o n i n j o i n t v e n t u r e w i t h E and B Canada R e s o u r c e s L t d i s l o c a t e d i n t h e n o r t h - e a s t c o r n e r of t h e s t u d y - a r e a on Mt. G r a v e s . The main m i n e r a l i z a t i o n on t h e p r o p e r t y i s c o n t a i n e d w i t h i n a wedge-shaped s i l i c i f i e d zone i n a n d e s i t e f l o w s o f t h e H a z e l t o n G r o u p ( P l a t e 5 - 8 ) . The zone has d i p s r a n g i n g f r o m 55 t o 65 d e g r e e s n o r t h e a s t , and r a n g e s i n w i d t h from 5 t o 35 m. Numerous a n d e s i t e d y k e s and a 10 m wide r h y o l i t e dyke segment t h e main showing and a p p e a r t o p o s t - d a t e m i n e r a l i z a t i o n . F i n e g r a i n e d g o l d , s i l v e r , a c a n t h i t e , p y r i t e and minor g a l e n a , s p h a l e r i t e and t e t r a h e d r i t e o c c u r w i t h i n s t o c k w o r k z o n e s c o n s i s t i n g o f a m e t h y s t i n e , w h i t e and c h a l c e d o n i c q u a r t z , c a l c i t e , h e m a t i t e , b a r i t e and m i n o r a l b i t e ( P l a t e 5 - 9 ) . Abundant j a r o s i t e and manganese o x i d e o c c u r on PLATE 5-8: Wedge-shaped s i l i c i f i e d zone o f the Mt. Graves p r o s p e c t . A t h i r t y - m e t r e - t h i c k r h y o l i t e dyke forms the f o o t w a l l o f t h e zone. Note abundant j a r o s i t e and manganese o x i d e s t a i n i n g on weathered a n d e s i t e s . Zone i s a p p r o x i m a t e l y 3 5 - m e t r e s - t h i c k where i t d i s a p p e a r s i n t o t a l u s . 117 weathered s u r f a c e s of the m i n e r a l i z e d zone. Gold occurs as i r r e g u l a r intergrowths with p y r i t e and as d i s s e m i n a t i o n s with s i l v e r and a c a n t h i t e ( P l a t e s 5-10 and 5-11). Gold appears to have formed simultaneously with p y r i t e , although i t may a l s o form replacement bodies. Grades of m i n e r a l i z a t i o n are e r r a t i c with some samples a s s a y i n g as high as 9.8 g per tonne gold and 6000 g per tonne s i l v e r . Ore t e x t u r e s i n c l u d e symmetrical banding, d r u s t y c o a t i n g s and c o l l o f o r m l a y e r i n g . As i s evident i n the Moosehorn prospect, a number of stages of s i l i c i f i c a t i o n and b r e c c i a t i o n can be recognized in the main s i l i c i f i e d zone on Mt. Graves. Most samples c o l l e c t e d show one or more of the f o l l o w i n g m i n e r a l i z a t i o n stages: Stage 1 : D e p o s i t i o n of amethystine and milky quartz l o c a l l y c o n t a i n i n g p y r i t e d i s s e m i n a t i o n s . T h i s p e r i o d of m i n e r a l i z a t i o n i s d i s t i n g u i s h e d from l a t e r episodes by g r e a t e r v e i n widths of up to 2.5 cm. Stage 2 and 3 : M i l k y quartz and minor b a r i t e , galena and s p h a l e r i t e are i n d i c a t i v e of these stages of d e p o s i t i o n . Both of the m i n e r a l i z a t i o n stages were fo l l o w e d by a p e r i o d of b r e c c i a t i o n . Stage 4 : Banded c h a l c e d o n i c , amethystine and milky quartz c o n t a i n i n g a c a n t h i t e , gold, s i l v e r , t e t r a h e d r i t e and p y r i t e . V e i n l e t s of t h i s stage r a r e l y exceed 0.5 cm i n width. Stage 5 : B r e c c i a t i o n f o l l o w e d by d e p o s i t i o n of c a l c i t e , s i d e r i t e , a l b i t e and minor b a r i t e . V e i n mineralogy and a l t e r a t i o n suggest that the Mt PLATE 5-9: Stockwork o f m i l k y , c h a l c e d o n i c and minor a m e t h y s t i n e q u a r t z i n a n d e s i t e from the Mt. Graves p r o s p e c t . PLATE 5-10: N a t i v e g o l d i n t e r g r o w n w i t h a c a n t h i t e and minor n a t i v e s i l v e r from t h e Mt. Graves d e p o s i t . Width o f p h o t o m i c r o g r a p h i s 0.5 mm. PLATE 5-11: Native gold intergrown w i t h p y r i t e . Gold may a l s o form replacement bodies a f t e r p y r i t e . Width o f photomicrograph i s 0.5 mm. 120 G r a v e s m i n e r a l i z a t i o n formed a t g r e a t e r d e p t h s w i t h i n t h e h y d r o t h e r m a l s y s t e m t h a n t h e Moosehorn p r o s p e c t . G e n e s i s w i l l be d i s c u s s e d f u r t h e r i n C h a p t e r 5.3 and 5.4. 5.3 F l u i d I n c l u s i o n Geothermometry  I n t r o d u c t i o n F l u i d i n c l u s i o n r e s e a r c h has been u n d e r t a k e n by s c i e n t i s t s f o r o v e r 100 y e a r s t o g a i n an u n d e r s t a n d i n g of h y d r o t h e r m a l f l u i d s , t h e i r c o m p o s i t i o n s , t e m p e r a t u r e o f emplacement, and g e n e s i s . In r e c e n t y e a r s f l u i d i n c l u s i o n g e o t h e r m o m e t r y has been u s e d as a t o o l i n m i n e r a l e x p l o r a t i o n t o h e l p d e f i n e t e m p e r a t u r e , p r e s s u r e and d e p t h of f o r m a t i o n o f h y d r o t h e r m a l o r e d e p o s i t s . In t h i s s t u d y , 97 f l u i d i n c l u s i o n s were examined u s i n g a Chaixmeca h e a t i n g / f r e e z i n g s t a g e mounted on a L e i t z O r t h o l u x I I b i n o c u l a r m i c r o s c o p e . The o b j e c t i v e was t o d e f i n e t h e t e m p e r a t u r e and d e p t h o f f o r m a t i o n as w e l l as t h e s a l i n i t i e s o f h y d r o t h e r m a l f l u i d s r e s p o n s i b l e f o r g o l d and s i l v e r m i n e r a l i z a t i o n i n t h e Toodoggone R i v e r a r e a . A n a l y t i c a l t e c h n i q u e s f o r t h e s t u d y of f l u i d i n c l u s i o n s a r e o u t l i n e d i n A p p e n d i x D. The d a t a o b t a i n e d from t h i s s t u d y a r e t a b u l a t e d i n A p p e n d i x B. T h e o r y F l u i d i n c l u s i o n s a r e samples of h y d r o t h e r m a l f l u i d s w h i c h a r e t r a p p e d i n c r y s t a l s by a v a r i e t y of mechanisms e i t h e r d u r i n g g r o w t h or by l a t e r p r o c e s s e s . They o c c u r i n g r e a t abundance i n a l m o s t a l l o r e and gangue m i n e r a l s , w i t h as many as a b i l l i o n p e r c u b i c c e n t i m e t r e ( R o e d d e r , 1977). To be u s e f u l f o r m i c r o g e o t h e r m o m e t r y , i n c l u s i o n s must g e n e r a l l y be g r e a t e r t h a n e i g h t M i n d i a m e t e r . F l u i d i n c l u s i o n s a r e s e l d o m of o n l y one g e n e r a t i o n , and t h e r e f o r e t h e t y p e of i n c l u s i o n under s t u d y must be a s c e r t a i n e d b e f o r e any c o n c l u s i o n s can be drawn a b o u t t h e g e n e s i s of an o r e body. I n c l u s i o n s t r a p p e d d u r i n g g r o w t h of th e h o s t c r y s t a l a r e d e f i n e d a s p r i m a r y i n c l u s i o n s , b e i n g c o n s i d e r e d a sample of t h e o r i g i n a l h y d r o t h e r m a l f l u i d s r e p o n s i b l e f o r m i n e r a l i z a t i o n . S e c o n d a r y i n c l u s i o n s a r e t h o s e formed by l a t e r s h e a r i n g and r e h e a l i n g o f f r a c t u r e s a f t e r t h e c r y s t a l l i z a t i o n of t h e h o s t m i n e r a l i s c o m p l e t e . P s e u d o s e c o n d a r y i n c l u s i o n s a r e i n f a c t s e c o n d a r y i n c l u s i o n s t r a p p e d d u r i n g t h e growth of t h e h o s t c r y s t a l . I f a c r y s t a l f r a c t u r e s d u r i n g g r o w t h , m i n e r a l i z i n g f l u i d s w i l l m i g r a t e a l o n g t h e c r a c k i n t o t h e c o r e o f t h e c r y s t a l . Such i n c l u s i o n s may have a d i f f e r e n t c o m p o s i t i o n t h a n t h o s e of p r i m a r y o r i g i n and t h u s a r e te r m e d p s e u d o s e c o n d a r y . C r i t e r i a f o r d i s t i n g u i s h i n g t h e s e t h r e e t y p e s o f f l u i d i n c l u s i o n s a r e o u t l i n e d by Roedder ( 1 9 7 6 ) . When u n d e r t a k i n g f l u i d i n c l u s i o n g e o t h e r m o m e t r y t o d e f i n e t e m p e r a t u r e and p r e s s u r e "of f o r m a t i o n o f a h y d r o t h e r m a l o r e d e p o s i t , as w e l l a s t h e s a l i n i t y o f t h e f l u i d a t t h e t i m e o f t r a p p i n g , t h e i n v e s t i g a t o r must make a number o f major a s s u m p t i o n s : 1) The f l u i d t r a p p e d upon s e a l i n g of t h e i n c l u s i o n was a s i n g l e , homogeneous p h a s e . 2) The c a v i t y i n w h i c h t h e f l u i d i s t r a p p e d d o e s n o t change 122 i n volume a f t e r s e a l i n g . 3) N o t h i n g i s added or l o s t f r o m t h e i n c l u s i o n a f t e r s e a l i n g . 4) The e f f e c t s o f p r e s s u r e a r e i n s i g n i f i c a n t o r a r e known. 5) The o r i g i n o f t h e i n c l u s i o n i s known. A l l o f t h e above a s s u m p t i o n s have been r e v i e w e d i n d e t a i l by Roedder (1981) and can r u l e d out as p o s s i b l e e r r o r s o u r c e s , or c o r r e c t e d f o r , i n f l u i d i n c l u s i o n r e s e a r c h . The h o m o g e n i z a t i o n method of g e o t h e r m o m e t r y i n v o l v e s h e a t i n g o f t h e i n c l u s i o n w h i l e w a t c h i n g f o r any phase c h a n g e s . Upon c o o l i n g , a f t e r t r a p p i n g o f a homogeneous f l u i d , a v a p o u r b u b b l e w i l l f o r m as a r e s u l t o f d i f f e r e n t i a l s h r i n k a g e o f t h e f l u i d and t h e h o s t c r y s t a l . The t e m p e r a t u r e o f h o m o g e n i z a t i o n i s t h e t e m p e r a t u r e a t w h i c h t h e v a p o u r b u b b l e and t h e l i q u i d homogenize t o a s i n g l e p h a s e . F l u i d i n c l u s i o n s may a l s o c o n t a i n i m m i s c i b l e l i q u i d s and d a u g h t e r c r y s t a l s , a l l o f w h i c h g e n e r a l l y i n c r e a s e t h e amount o f knowledge t h a t c a n be g a i n e d from t h e h o m o g e n i z a t i o n method. The t e m p e r a t u r e o f h o m o g e n i z a t i o n i s g e n e r a l l y a minimum v a l u e f o r t h e t e m p e r a t u r e of f o r m a t i o n of a m i n e r a l . As a r e s u l t of t h e c o m p r e s s i b i l i t y o f f l u i d s , a p r e s s u r e c o r r e c t i o n b a s e d on g e o l o g i c a l e v i d e n c e must be added t o t h e t e m p e r a t u r e of h o m o g e n i z a t i o n t o o b t a i n t h e t e m p e r a t u r e o f f o r m a t i o n . No p r e s s u r e c o r r e c t i o n i s n e c e s s a r y i f t h e i n c l u s i o n s l i e on t h e b o i l i n g c u r v e f o r t h e s y s t e m d e s c r i b e d by t h e components o f t h e i n c l u s i o n . Once a t e m p e r a t u r e of f o r m a t i o n has been c a l c u l a t e d t h e p r e s s u r e a t t h e t i m e of 123 f o r m a t i o n , and t h e d e n s i t y of t h e m i n e r a l i z a t i o n f l u i d s c a n be e s t i m a t e d by u s i n g p u b l i s h e d g r a p h s and t a b l e s f o r t h a t s y s t e m . C o m p o s i t i o n s o f f l u i d s w i t h i n i n c l u s i o n s c a n be d e t e r m i n e d u s i n g s p e c t r o s c o p i c t e c h n i q u e s t h a t g e n e r a l l y i n v o l v e o p e n i n g up t h e i n c l u s i o n and a n a l y z i n g t h e f l u i d r e l e a s e d . However, f l u i d c o m p o s i t i o n s a l s o c a n be e s t i m a t e d by f r e e z i n g t h e i n c l u s i o n s and w a t c h i n g t h e s u b s e q u e n t phase c h a n g e s . Upon r a p i d f r e e z i n g and s u b s e q u e n t h e a t i n g of f l u i d i n c l u s i o n s two i m p o r t a n t o b s e r v a t i o n s a r e r o u t i n e l y r e c o r d e d : 1) t h e t e m p e r a t u r e of f i r s t m e l t i n g o r t h e e u t e c t i c m e l t i n g t e m p e r a t u r e , and 2) t h e l a s t m e l t i n g o f t h e i c e . The t e m p e r a t u r e of e u t e c t i c m e l t i n g i s u n i q u e f o r e v e r y s y s t e m , and t h u s c an p r o v i d e i m p o r t a n t i n f o r m a t i o n a b o u t t h e components o f t h e s y s t e m . D e t e c t i o n of t h e p o i n t of e u t e c t i c m e l t i n g u n f o r t u n a t l e l y i s d i f f i c u l t and u s u a l l y i m p o s s i b l e t o r e c o g n i z e i n i n c l u s i o n s l e s s t h a n 10 n i n d i a m e t e r . The l a s t m e l t i n g o f i c e can be u s e d t o d e t e r m i n e s a l i n i t i e s o f f l u i d s i n i n c l u s i o n s . In t h i s method, t h e o b s e r v e d f r e e z i n g p o i n t d e p r e s s i o n i s u s e d t o c a l c u l a t e t h e e q u i v a l e n t amount o f N a C l t h a t would c a u s e a s i m i l a r f r e e z i n g p o i n t d e p r e s s i o n i n t h e s y s t e m N a C l - H 2 0 ( P o t t e r , 1978). The major s h o r t - c o m i n g of t h i s method i s t h a t i t does n o t t a k e i n t o a c c o u n t t h e e f f e c t s of o t h e r common s a l t s s u c h as C a C l 2 and K C l on t h e f r e e z i n g p o i n t d e p r e s s i o n . A t low t o t a l s a l t c o n c e n t r a t i o n however, e x p r e s s i n g s a l i n i t i e s i n t e r m s o f e q u i v a l e n t w e i g h t p e r c e n t N a C l , i s an a c c u r a t e 124 e s t i m a t i o n o f t h e amount o f d i s s o l v e d s a l t s i n f l u i d i n c l u s i o n s . Method o f S t u d y F i f t y f l u i d i n c l u s i o n s a m p l e s were c o l l e c t e d f r o m o u t c r o p s o f b o t h t h e Moosehorn Amethyst B r e c c i a zone and Mt G r a v e s z o n e . S e l e c t i o n o f s a m p l e s was b a s e d on t h e abundance and c l a r i t y of o r e - s t a g e a m e t h y s t , and on t h e i r s p a t i a l d i s t r i b u t i o n t h r o u g h o u t t h e v e i n s y s t e m . T w e n t y - f i v e d o u b l y p o l i s h e d t h i n s e c t i o n s o f a b o u t 0.1 mm t h i c k n e s s were examined f r o m t h e two p r o s p e c t s . A p p e n d i x D g i v e s a d e t a i l e d d e s c r i p t i o n o f t h e a n a l y t i c a l p r o c e d u r e s i n f l u i d i n c l u s i o n r e s e a r c h . P r i m a r y , p s e u d o s e c o n d a r y and s e c o n d a r y i n c l u s i o n s were u s e d d u r i n g t h i s s t u d y o f h o m o g e n i z a t i o n and d e p r e s s i o n o f f r e e z i n g p o i n t s . C a r e was t a k e n t o i n s u r e t h a t o n l y t h o s e i n c l u s i o n s whose o r i g i n s were c l e a r l y r e c o g n i z a b l e were u s e d f o r t e m p e r a t u r e d e t e r m i n a t i o n s . Ambiguous i n c l u s i o n s were a v o i d e d . T a b l e 5-1 summarizes t h e i n f o r m a t i o n o b t a i n e d from t h e s e s a m p l e s . H i s t o g r a m s of t h e h o m o g e n i z a t i o n and l a s t m e l t i n g t e m p e r a t u r e s a r e d e p i c t e d i n F i g u r e s 5-1 and'5-2 r e s p e c t i v e l y . F i g u r e 5~4 i s a p l o t of h o m o g e n i z a t i o n v e r s u s l a s t m e l t i n g t e m p e r a t u r e s f o r f l u i d i n c l u s i o n s from t h e two p r o s p e c t s . M oosehorn Amethyst B r e c c i a Zone ' S i x t y - s i x f l u i d i n c l u s i o n s i n a m e t h y s t and s i x 125 i n c l u s i o n s i n c a l c i t e were examined, and c a n be g r o u p e d on t h e b a s i s o f p r i m a r y , s e c o n d a r y and p s e d o s e c o n d a r y o r i g i n . A l l i n c l u s i o n s c o n t a i n an aqueous phase and a v a p o u r b u b b l e . C o n c e n t r a t i o n s o f C 0 2 a r e n e g l i g i b l e w i t h i n t h e i n c l u s i o n s a s i n d i c a t e d by t h e a b s e n c e o f a s e p a r a t e C 0 2 phase below +31°C (R o e d d e r , 1963) and by t h e r e l a t i v e l y low l a s t m e l t i n g t e m p e r a t u r e s ( C o l l i n s , 1979). P r i m a r y i n c l u s i o n s i n a m e t h y s t have h o m o g e n i z a t i o n t e m p e r a t u r e s r a n g i n g from 211°C t o 251°C ( a v e r a g e 2 3 2 ° C ) . A l l i n c l u s i o n s homogenize t o a l i q u i d p h a s e . A t y p i c a l i n c l u s i o n of t h i s t y p e has a p e r c e n t v a p o u r , 100V/(V+L), o f between 5 and 20 p e r c e n t , and an a v e r a g e s i z e o f 9 n by 12 n ( F i g u r e 5 - 3 a ) . P r i m a r y i n c l u s i o n s a r e g e n e r a l l y somewhat r o u n d e d , commonly t a p e r i n g a t one end t o form a c u s p ( F i g u r e 5 - 3 b ) . L a s t m e l t i n g t e m p e r a t u r e s r a n g e i n v a l u e between -0.6°C and - 3 . 9 ° C . U s i n g t h e f o r m u l a e o f P o t t e r ( l 9 7 8 ) t h e o b s e r v e d l a s t m e l t i n g t e m p e r a t u r e s c o r r e s p o n d t o f l u i d s w i t h between 1.0 and 6.3 ( a v e r a g e 3.3) e q u i v a l e n t w e i g h t p e r c e n t N a C l . L a s t m e l t i n g t e m p e r a t u r e s c o u l d not be a c c u r a t e l y m e a sured i n i n c l u s i o n s w i t h a r e a s of l e s s t h a n 50 s q u a r e m i c r o n s . S e c o n d a r y i n c l u s i o n s i n a m e t h y s t a r e s m a l l e r (5 M by 9 fx) more e l o n g a t e t h a n p r i m a r y i n c l u s i o n s and o c c u r i n p l a n a r s h e e t s a l o n g f r a c t u r e s ( F i g u r e 5 - 3 c ) . S e c o n d a r y i n c l u s i o n s have l o w e r h o m o g e n i z a t i o n t e m p e r a t u r e s t h a n i n c l u s i o n s o f p r i m a r y o r i g i n , w i t h v a l u e s r a n g i n g between 159°C and 185°C ( a v e r a g e 1 7 0 ° C ) , w i t h 100V/(V+L) c o n s i s t e n t l y r a n g i n g from 5 t o 10 p e r c e n t . S a l i n i t i e s i n t h e s e i n c l u s i o n s a r e s l i g h t l y TABLE 5-1 Summary of F l u i d Inclusion Data from the Mt. Graves and Moosehorn Gold and S i l v e r Prospects MOOSEHORN AMETHYST BRECCIA ZONE 4 Total 1 2 3 Host Inclusion Data Number of Range of Mineral Type Measured Inclusions Values Mean AM PR Th 38 211.8 to 250.7 232.4 AM PR Tm 30 -0.6 to -3.9 -1.9 AM PR % NaCl 30 1.0 to 6.3 3.3 AM SE Th 19 159.5 to 185.2 170.0 AM SE Tm 15 -0.2 to -3.1 -1.7 AM SE % NaCl 15 0.4 to 5.1 2.8 AM PS Th 3 203.4 to 207.5 205.2 AM PS Tm NVO NVO NVO AM PS % NaCl NVO NVO NVO CC PR Th 6 116.4 to 145.9 131.4 CC PR Tm 3 -0.2 to -1.5 -0.7 cc PR % NaCl 3 0.4 to 2.6 1.2 MT. GRAVES ZONE AM PR Th 20 245.6 to 296.1 267.2 AM PR Tm 18 -2.1 to -5.1 -4.1 AM PR % NaCl 18 3.6 to 7.8 6.5 AM SE Th 11 199.3 to 226.4 210.2 AM SE Tm 9 -1.9 to -3.1 -2.3 AM SE % NaCl 9 3.2 to 5.1 3.8 Range of % Vapour 100V/CV+L) Average Inclusion Size (u) 5-20 9 by 12 5-20 9 by 12 5-20 9 by 12 5-10 5 by 9 5-10 5 by 9 5-10 5 by 9 5-10 5 by 7 5-10 5 by 7 5-10 5 by 7 5-10 6 by 8 5-10 6 by 8 5-10 6 by 8 5-45 8 by 11 5-45 8 by 11 5-45 8 by 11 5-10 4 by 8 5-10 4 by 8 5-10 4 by 8 127 F o o t n o t e s f o r TABLE 5-1 1. AM - a m e t h y s t CC - c a l c i t e 2. PR - p r i m a r y i n c l u s i o n s PS - p s e u d o s e c o n d a r y i n c l u s i o n s SE - s e c o n d a r y i n c l u s i o n s 3. Th - h o m o g e n i z a t i o n t e m p e r a t u r e i n °C Tm - l a s t m e l t i n g t e m p e r a t u r e o f i c e i n °C % N a C l - c a l c u l a t e d e q u i v a l e n t w e i g h t p e r c e n t N a C l 4. NVO - no v a l u e o b t a i n e d M o o s e h o r n A m e t h y s t B r e c c i a Z o n e 12 -10 -8 -6 4 H 1 0 0 N =66 1 4 0 1 8 0 2 2 0 2 6 0 3 0 0 12 1 10 8 -6 -Mt. G r a v e s Z o n e M =29 1 0 0 1 4 0 1 8 0 2 2 0 2 6 0 3 0 0 Homogenizat ion Temperature (°C) FIGURE 5-1: Histograms o f h o m o g e n i z a t i o n t e m p e r a t u r e s f o r f l u i d i n c l u s i o n s i n samples from t h e Mt. Graves and Moosehorn g o l d and s i l v e r p r o s p e c t s . U n p a t t e r n e d a r e a s r e p r e s e n t p r i m a r y i n c l u s i o n s i n amethyst; s t i p l e d r e g i o n s r e p r e s e n t secondary i n c l u s i o n s i n amethyst; h o r i z o n t a l l i n e d a r e a s r e p r e s e n t p r i m a r y i n c l u s i o n s i n c a l c i t e and d i a g o n a l l i n e d a r e a s r e p r e s e n t pseudosecondary i n c l u s i o n s i n amethyst. 129 Moosehorn Amethyst B r e c c i a Zone N 10 • 8 -6 -4 2 -12-10 -8 -6 - 4 -2 N = 49 6 8 Mt. G r a v e s Zone M 10 -\ 8 6 -4 -2 -— r -12 -10 -8 -6 -4 -2 0 2 4 6 8 Las t Melting Tempera ture (°C) M = 27 FIGURE 5-2: Hi s t o g r a m s o f l a s t m e l t i n g t e m p e r a t u r e s f o r f l u i d i n c l u s i o n s i n samples from t h e Mt. Graves and Moosehorn p r o s p e c t s . Symbols a r e as i n F i g u r e 5-1. 130 3a 1/* 3d 3a. p r i m a r y i n c l u s i o n . i n a m e t h y s t 3b. p r i m a r y i n c l u s i o n i n a m e t h y s t 3c. s e c o n d a r y i n c l u s i o n i n a m e t h y s t 3d. p s e u d o s e c o n d a r y i n c l u s i o n i n a m e t h y s t 3e. p r i m a r y i n c l u s i o n i n c a l c i t e FIGURE 5-3: D r a w i n g s o f f l u i d i n c l u s i o n s i n a m e t h y s t and c a l c i t e f r o m t h e Moosehorn p r o s p e c t . 131 l o w e r t h a n f o r p r i m a r y ones, r a n g i n g from 0.4 t o 5.1 ( a v e r a g e 2.8) e q u i v a l e n t w e i g h t p e r c e n t N a C l . Vapour b u b b l e s i n s e c o n d a r y i n c l u s i o n s a r e u s u a l l y i n c o n s t a n t m o t i o n , p o s s i b l y i n r e s p o n s e t o v a r y i n g t h e r m a l g r a d i e n t s p r o d u c e d by t h e m i c r o s c o p e l i g h t and h e a t i n g s t a g e ( R o e d d e r , 1967) . The c r i t e r i a f o r t h e i d e n t i f i c a t i o n o f p s e u d o s e c o n d a r y i n c l u s i o n s a r e p o o r l y d e f i n e d , and must be a p p l i e d w i t h g r e a t c a r e as t h e r e i s c o n s i d e r a b l e c h a n c e f o r a m b i g u i t y . T h r e e i n c l u s i o n s , o f t h e h u n d r e d s t h a t were s t u d i e d a p p e a r t o meet t h e g e n e r a l r e q u i r e m e n t s o u t l i n e d by Roedder (1976) f o r p s e u d o s e c o n d a r y o r i g i n , a l t h o u g h t h e e v i d e n c e i s by no means c o n c l u s i v e . H o m o g e n i z a t i o n t e m p e r a t u r e s r a n g e from 203°C t o 207°C w i t h i n c l u s i o n s h a v i n g 5 t o 10 p e r c e n t e s t i m a t e d 100V/(V+L). I n c l u s i o n s o f t h i s t y p e were g e n e r a l l y t o o s m a l l t o a l l o w d e t e r m i n a t i o n o f l a s t m e l t i n g t e m p e r a t u r e s . P r i m a r y i n c l u s i o n s i n c a l c i t e have a l l t h e m o r p h o l o g i c a l f e a t u r e s of p r i m a r y i n c l u s i o n s i n a m e t h y s t a l t h o u g h t h e c a l c i t e i n c l u s i o n s a r e c o n s i d e r a b l y s m a l l e r , a v e r a g i n g 6 y by 8 M ( F i g u r e 5 - 3 e ) . H o m o g e n i z a t i o n t e m p e r a t u r e s a r e much l o w e r t h a n f o r i n c l u s i o n s i n a m e t h y s t r a n g i n g f r o m 116°C t o 146°C ( a v e r a g e 1 3 1 ° C ) . S a l i n i t i e s e x h i b i t a s i m i l a r d e c l i n e r a n g i n g between 0.4 and 2.6 e q u i v a l e n t w e i g h t p e r c e n t N a C l . C a l c i t e f r o m t h e Moosehorn p r o s p e c t i s g e n e r a l l y m i l k y w h i t e , and c l o u d e d by b i l l i o n s o f i n c l u s i o n s , r e n d e r i n g i t u s e l e s s f o r m i c r o g e o t h e r m o m e t r y . 132 Mt. G r a v e s P r o s p e c t From h u n d r e d s of i n c l u s i o n s t h a t were examined i n o r e - s t a g e a m e t h y s t , o n l y 31 were o f s u f f i c i e n t s i z e and c l a r i t y t o w a r r a n t a n a l y s i s . P r i m a r y and s e c o n d a r y i n c l u s i o n s p r o v e d u s e f u l f o r d e t e r m i n a t i o n o f h o m o g e n i z a t i o n and l a s t m e l t i n g t e m p e r a t u r e s . P s e u d o s e c o n d a r y i n c l u s i o n s were n o t s u i t a b l e f o r use i n g e o t h e r m o m e t r y . A l l i n c l u s i o n s c o n t a i n l i q u i d and v a p o u r p h a s e s . P r i m a r y i n c l u s i o n s have h i g h e r h o m o g e n i z a t i o n t e m p e r a t u r e s t h a n t h o s e of t h e Moosehorn p r o s p e c t , w i t h v a l u e s f o r Mt. G r a v e s i n c l u s i o n s r a n g i n g between 246°C and 296°C ( a v e r a g e 2 6 7 ° C ) . V a r i a b l e v a p o u r c o n t e n t s r a n g i n g from 5 t o 45 p e r c e n t c h a r a c t e r i z e t h e s e p r i m a r y i n c l u s i o n s . T h i s v a r i a b i l i t y i s c o n s i d e r e d t o be e v i d e n c e f o r b o i l i n g d u r i n g t h e f o r m a t i o n of t h e i n c l u s i o n (Rye and S a w k i n s , 1974), a l t h o u g h p h y s i c a l c h a n g e s s u c h as l e a k a g e and n e c k i n g down may a l s o be r e s p o n s i b l e . The h i g h 100V/(V+L) v a l u e s i n v a l i d a t e t h e use of t h e s e i n c l u s i o n s i n g e o t h e r m o m e t r y u s i n g t h e h o m o g e n i z a t i o n method (Ro e d d e r , 1981). F i v e of t h e 20 p r i m a r y i n c l u s i o n s s t u d i e d from t h e Mt G r a v e s p r o s p e c t had v a r i a b l e 100V/(V+L) r a t i o s of between 25 and 45 p e r c e n t . T e m p e r a t u r e s o f h o m o g e n i z a t i o n f o r t h e s e i n c l u s i o n s range from 212°C t o 269°C ( a v e r a g e 2 4 2 ° C ) . A l l p r i m a r y i n c l u s i o n s w i t h h i g h 100V/(V+L) r a t i o s h o m o g e n i z e d t o a l i q u i d p h a s e . Had any o f them h o m o g e n i z e d t o a v a p o u r p h a s e , t h i s d a t a might have been u s e d t o p r e c i s e l y d e f i n e t h e t e m p e r a t u r e and p r e s s u r e o f f o r m a t i o n of t h e d e p o s i t ( R o e d d e r , 1981). T y p i c a l p r i m a r y i n c l u s i o n s a r e 8 M by 11 n 133 O o CD 1_ Z3 •4-> CO i— CD a E CD c o +-CO N C CD CO O E o I Equivalent Weight % NaCl 3 0 0 -2 5 0 -2 0 0 -1 5 0 1 0 0 7 . 7 2 5 . 0 0 — i 1.72 0 /•VZ/ • v V ' ml V. - 6 - 5 - 4 - 3 - 2 - 1 0 1 2 Last Melting Temperature CO • M o o s e h o r n p r i m a r y i n c l u s i o n s i n a m e t h y s t • M o o s e h o r n s e c o n d a r y i n c l u s i o n s i n a m e t h y s t A M o o s e h o r n p r i m a r y i n c l u s i o n s i n c a l c i t e v M t . G r a v e s p r i m a r y i n c l u s i o n s i n a m e t h y s t o M t . G r a v e s s e c o n d a r y i n c l u s i o n s i n a m e t h y s t FIGURE 5-4: P l o t o f l a s t m e l t i n g t e m p e r a t u r e s v e r s u s h o m o g e n i z a t i o n t e m p e r a t u r e s f o r f l u i d i n c l u s i o n s from the Mt. Graves and Moosehorn p r o s p e c t s . I n c l u s i o n s a r e grouped on the b a s i s o f d e p o s i t and o r i g i n . 134 FIGURE 5-5: Drawings o f f l u i d i n c l u s i o n s i n amethyst from t h e Mt. Graves p r o s p e c t . 135 and o c c u r as i s o l a t e d b u b b l e s , s e p a r a t e d from n e i g h b o u r i n g i n c l u s i o n s by a minimum d i s t a n c e of 20 M. L a s t m e l t i n g t e m p e r a t u r e s range from between -2.1°C and -5.1°C ( a v e r a g e - 4 . 1 ° C ) , and c o r r e s p o n d t o between 3.6 and 7.8 ( a v e r a g e 6.5 e q u i v a l e n t w e i g h t p e r c e n t N a C l ) . F l u i d s from Mt. G r a v e s a r e a l m o s t t w i c e as s a l i n e (6.5 e q u i v a l e n t w e i g h t p e r c e n t N a C l ) as t h e f l u i d s i n i n c l u s i o n s f r o m Moosehorn (3.3 e q u i v a l e n t w e i g h t p e r c e n t N a C l ) . T y p i c a l e xamples of t h e s h a p e s of p r i m a r y i n c l u s i o n s f o u n d i n a m e t h y s t from t h e Mt. G r a v e s p r o s p e c t a r e i n F i g u r e s 5-5a and 5-5b. S e c o n d a r y i n c l u s i o n s i n a m e t h y s t have h o m o g e n i z a t i o n t e m p e r a t u r e s r a n g i n g between 199°C and 226°C. They o c c u r i n g r o u p s a l o n g f r a c t u r e p l a n e s and a v e r a g e 4 n by 8 u i n s i z e . V apour c o n t e n t s a r e c o n s i s t a n t t h r o u g h o u t a l l s e c o n d a r y i n c l u s i o n s , r a n g i n g from 5 t o 10 p e r c e n t . S a l i n i t i e s r a n g e from 3.2 t o 5.1 ( a v e r a g e 3.8 e q u i v a l e n t p e r c e n t N a C l ) , s l i g h t l y g r e a t e r t h a n f o r s e c o n d a r y i n c l u s i o n s from t h e Moosehorn p r o s p e c t . F i g u r e s 5-5c and 5-5d show t y p i c a l s e c o n d a r y i n c l u s i o n s a s f o u n d i n a m e t h y s t from Mt. G r a v e s . D i s c u s s i o n o f R e s u l t s and G e n e s i s P r i m a r y and s e c o n d a r y i n c l u s i o n s i n a m e t h y s t from t h e Moosehorn and Mt. G r a v e s d e p o s i t s do not o c c u r i n s p a t i a l l y d i s t i n c t r e g i o n s o f t h e v e i n s y s t e m s . In b o t h c a s e s , p r i m a r y i n c l u s i o n s have h i g h e r h o m o g e n i z a t i o n t e m p e r a t u r e s t h a n t h o s e of s e c o n d a r y o r i g i n , i n d i c a t i n g a f a l l o f t e m p e r a t u r e s u b s e q u e n t t o m i n e r a l i z a t i o n . B e f o r e e s t i m a t i n g f o r m a t i o n d e p t h s , h o m o g e n i z a t i o n t e m p e r a t u r e s must be 136 c o r r e c t e d f o r t h e e f f e c t s of p r e s s u r e on t h e s y s t e m . D u r i n g e p i s o d e s o f b o i l i n g t h e v a p o u r p r e s s u r e of h y d r o t h e r m a l f l u i d s must be e q u a l t o t h e p r e s s u r e of t h e s y s t e m , and t h u s no p r e s s u r e c o r r e c t i o n i s n e c e s s a r y f o r h o m o g e n i z a t i o n t e m p e r a t u r e s o f f l u i d i n c l u s i o n s t r a p p e d a t s u c h t i m e s . T h e r e f o r e , t h e t e m p e r a t u r e s of h o m o g e n i z a t i o n of p r i m a r y i n c l u s i o n s f r o m t h e Mt. G r a v e s zone a r e e q u a l t o t h e t e m p e r a t u r e of f o r m a t i o n . The t e m p e r a t u r e of h o m o g e n i z a t i o n f o r a l l o t h e r i n c l u s i o n s r e p r e s e n t s t h e minimum v a l u e of t h e t e m p e r a t u r e of f o r m a t i o n as t h e r e i s no o b v i o u s e v i d e n c e t h a t b o i l i n g o c c u r e d d u r i n g d e p o s i t i o n . P r e s s u r e c o r r e c t i o n s a r e g e n e r a l l y e s t i m a t e d from g e o l o g i c a l d a t a s u c h as d e p t h o f c o v e r a t t h e t i m e o f m i n e r a l i z a t i o n (Roedder and Bodnar, 1980). E s t i m a t e s o f p r e s s u r e c o r r e c t i o n s t o t e m p e r a t u r e s f o r e p i t h e r m a l g o l d d e p o s i t s r a n g e from 0°C t o 25°C (Nash, 1972; R o e d d e r , 1977). In t h e Toodoggone R i v e r a r e a most d e p o s i t s o c c u r w i t h i n t h e u p p e r p o r t i o n s o f a n d e s i t e and t r a c h y t e flows." S t r a t i g r a p h i c a l l y above t h e s e h o s t r o c k s l i e d a c i t i c a s h - f l o w t u f f s . T h e s e d a c i t e s do not a p p e a r t o be a p p r e c i a b l y a f f e c t e d by h y d r o t h e r m a l a c t i v i t y , and e x h i b i t a c o m p l e t e l y d i f f e r e n t f o r m o f : a l t e r a t i o n t h a n t h e a n d e s i t e s . The a u t h o r b e l i e v e s t h a t t h e d a c i t i c a s h f l o w s r e p r e s e n t p o s t m i n e r a l i z a t i o n v o l c a n i s m and s h o u l d t h e r e f o r e not be c o n s i d e r e d i n any p r e s s u r e c o r r e c t i o n e s t i m a t e s . S t r a t i g r a p h i c e v i d e n c e i n d i c a t e s a maximum d e p t h of b u r i a l o f between 100 and 200 m e t r e s . U s i n g t h e s e e s t i m a t e s , from g r a p h s of P o t t e r (1977) p r e s s u r e c o r r e c t i o n s 137 to temperatures would be between 2°C and 10°C. T h i s c o r r e c t i o n f a c t o r i s thought to be i n s i g n i f i c a n t compared to the range i n estimated v a l u e s , and t h e r e f o r e homogenization temperatures are taken to be roughly equal to formation temperatures. Observed mean s a l i n i t i e s w i t h i n i n c l u s i o n s from both the Moosehorn and Mt. Graves propects range from 0.8 to 6.5 e q u i v a l e n t weight percent NaCl. The decrease i n s a l i n i t y from 6.5 e q u i v a l e n t weight percent NaCl i n the Mt. Graves i n c l u s i o n s to 3.3 e q u i v a l e n t weight percent NaCl i n the Moosehorn i n c l u s i o n s p o s s i b l y can be a t t r i b u t e d to the mixing of low s a l i n i t y groundwater, with the i n i t i a l hydrothermal f l u i d s . Secondary i n c l u s i o n s from both p r o s p e c t s show c o n s i s t a n t s a l i n i t i e s of between 2.3 and 2.8 e q u i v a l e n t weight percent NaCl. C a l c i t e , i s t y p i f i e d by l a t e d e p o s i t i o n i n the p a r a g e n e t i c sequence of m i n e r a l i z a t i o n and has primary i n c l u s i o n s with much lower mean s a l i n i t i e s , i n d i c a t i n g a s i g n i f i c a n t change i n the c h a r a c t e r of the hydrothermal f l u i d s subsequent to ore d e p o s i t i o n . Estimates of the depth of formation of v e i n s i n the Moosehorn and Mt. Graves p r o p e c t s , based on homogenization temperatures and s a l i n i t i e s can be made using data from Haas (1971), assuming h y d r o s t a t i c p r e s s u r e s . Minimum depth estimates f o r primary i n c l u s i o n s i n amethyst from the Moosehorn prospect range from 200 m to 448 m (average 305 m). Secondary i n c l u s i o n s were formed at depths of between 80 mv and 200 m (average 100 m). Average homogenization 133 t e m p e r a t u r e s and s a l i n i t i e s a r e g r e a t e r f o r samples c o l l e c t e d on t h e west s i d e of Moosehorn C r e e k (239°C and 3.5 e q u i v a l e n t w e i g h t p e r c e n t N a C l ) , t h a n f o r t h o s e c o l l e c t e d f r o m t h e e a s t s i d e of t h e can y o n (228°C and 3.1 e q u i v a l e n t w e i g h t p e r c e n t N a C l ) . T h i s d i s c r e p a n c y can be i n t e r p r e t e d a s i n d i c a t i n g t h e p r e s e n c e of a p o s t - m i n e r a l i z a t i o n n o r m a l f a u l t c o i n c i d e n t w i t h t h e c r e e k c a n y o n . On t h e west s i d e of t h e c r e e k a d e e p e r l e v e l o f t h e h y d r o t h e r m a l s y s t e m i s e x p o s e d and t h u s s a l i n i t i e s and t e m p e r a t u r e s a r e h i g h e r ( F i g u r e 5 - 6 ) . S t r a t i g r a p h i c e v i d e n c e a l s o s u p p o r t s t h i s h y p o t h e s i s (Chaper 5 . 2 ) . P r i m a r y i n c l u s i o n s i n c a l c i t e have minimum d e p t h s o f f o r m a t i o n s r a n g i n g from 8 m t o 34 m ( a v e r a g e 17 m). D e p t h s of f o r m a t i o n of p s e u d o s e c o n d a r y i n c l u s i o n s i n a m e t h y s t were not c a l c u l a t e d , b e c a u s e so few h o m o g e n i z a t i o n t e m p e r a t u r e s were r e c o r d e d , and no s a l i n i t i e s c o u l d be e s t i m a t e d b e c a u s e of t h e s m a l l s i z e and p o o r c l a r i t y of i n c l u s i o n s . D e p t h s o f f o r m a t i o n f o r Mt. G r a v e s f l u i d i n c l u s i o n s a s s u m i n g h y d r o s t a t i c l o a d s , a r e much g r e a t e r t h a n f o r t h e Moosehorn i n c l u s i o n s ; r a n g i n g from 160 m t o 1,020 m. P r i m a r y i n c l u s i o n s i n a m e t h y s t have an e s t i m a t e d d e p t h of f o r m a t i o n o f between 390 m and 1,020 m ( a v e r a g e 609 m). S e c o n d a r y i n c l u s i o n s formed a t d e p t h s o f between 160 m and 305 m ( a v e r a g e 210 m). Minimum d e p t h s o f f o r m a t i o n , above, have been e s t i m a t e d a s s u m i n g t h a t t h e s y s t e m i s f r e e l y c o n n e c t e d t o t h e s u r f a c e and on t h e b o i l i n g c u r v e . D i s c r e p a n c i e s between t h e t e m p e r a t u r e and d e p t h of f o r m a t i o n of p r i m a r y and s e c o n d a r y 139 FIGURE 5-6: D i a g r a m a t i c c r o s s s e c t i o n o f t h e Moosehorn Amethyst B r e c c i a zone, i n the Moosehorn Creek canyon. View i s l o o k i n g n o r t h . A b b r e v i a t i o n s a r e as f o l l o w s : Th means h o m o g e n i z a t i o n t e m p e r a t u r e , eq. wt. %NaCl means e q u i v a l e n t w e i g h t p e r c e n t N a C l . 140 i n c l u s i o n s , i n d i c a t e s t h a t a more c o m p l i c a t e d p r e s s u r e r e g i m e i s i n v o l v e d r a t h e r t h a n s i m p l y h y d r o s t a t i c l o a d s . W h i l e i t i s p o s s i b l e t h a t Moosehorn p r i m a r y i n c l u s i o n s i n a m e t h y s t f o r m e d a t 305 m under h y d r o s t a t i c c o n d i t i o n s as o u t l i n e d by Haas ( 1 9 7 1 ) , i t i s more l i k e l y t h a t t h e y formed under t h e e f f e c t s o f l i t h o s t a t i c p r e s s u r e s a t a p p r o x i m a t e l y t h e same d e p t h s as s e c o n d a r y i n c l u s i o n s . U s i n g t h e d a t a o f Kennedy ( 1 9 5 0 ) , p r i m a r y i n c l u s i o n s t h a t formed a t 305 m under t h e e f f e c t s of h y d r o s t a t i c p r e s s u r e s , would form a t a d e p t h o f a p p r o x i m a t e l y 115 m a s s u m i n g l i t h o s t a t i c p r e s s u r e s . S i m i l a r l y , Mt. G r a v e s p r i m a r y i n c l u s i o n s would have formed a t a d e p t h o f 225 m, a s s u m i n g l i t h o s t a t i c l o a d s , w h i c h i s t h e a p p r o x i m a t e d e p t h o f f o r m a t i o n f o r Mt. G r a v e s s e c o n d a r y i n c l u s i o n s formed under e s s e n t i a l l y h y d r o s t a t i c c o n d i t i o n s . The d a t a t h u s can b e s t be e x p l a i n e d by u t i l i z i n g t h e t h r o t t l i n g model of B a r t o n and T o u l m i n ( 1 9 6 1 ) . Below t h e t i g h t , a l m o s t c l o s e d t h r o t t l e , p r e s s u r e s a r e a p p r o x i m a t e l y l i t h o s t a t i c , w i t h t h e Moosehorn and Mt. G r a v e s p r i m a r y i n c l u s i o n s f o r m i n g below t h i s c o n s t r i c t i o n a t t h e d e p t h s i n d i c a t e d on F i g u r e 5-7. In t h e Mt. G r a v e s d e p o s i t , o r e m i n e r a l s were d e p o s i t e d from b o i l i n g f l u i d s as i n d i c a t e d by t h e v a r i a b l e v a p o u r t o l i q u i d r a t i o s i n p r i m a r y i n c l u s i o n s . The d e p t h a t w h i c h b o i l i n g o c c u r s i s d i r e c t l y r e l a t e d t o t h e p r e s s u r e and t e m p e r a t u r e o f t h e s y s t e m and i n v e r s e l y r e l a t e d t o t h e s a l i n i t y of t h e m i n e r a l i z i n g f l u i d s . T h e r e f o r e , any c h a n g e s i n t e m p e r a t u r e , p r e s s u r e or s a l i n i t y w i l l c a u s e a change i n t h e a p p a r e n t d e p t h o f m i n e r a l d e p o s i t i o n . I t s h o u l d be n o t e d h e r e t h a t d e p t h s o f f o r m a t i o n have 141 Paleosurface THROTTLE POINT Temp: 212 to 251°C Salinity: 3.3 eq wt %NaCI Grade: 2.8 g/tonne Au 56 g/tonne Ag Mineralogy: Native A g ' Acanthite Non-boiling Temp: 245 to 296°C Salinity: 6.5 eq wt %NaCI Grade: 9.8 g/tonne Au 560 g/tonne Ag Mineralogy: Native Au Native Ag Tetrahedrite Acanthite Galena Sphalerite Boiling MOOSEHORN 115 m r- 0 -100 o T3 -200 MT. GRAVES 225 m -300 FIGURE 5-7: Model f o r t h e f o r m a t i o n o f Toodoggone R i v e r a r e a g o l d and s i l v e r d e p o s i t s based on p r i m a r y and secondary f l u i d i n c l u s i o n s t u d i e s . A b b r e v i a t i o n s a r e as f o l l o w s : eq wt %NaCl means e q u i v a l e n t w e i g h t p e r c e n t N a C l , g/tonne means grams per tonne, Temp means Temperature. 14 2 been c a l c u l a t e d u t i l i z i n g t h e a v e r a g e h o m o g e n i z a t i o n t e m p e r a t u r e s and s a l i n i t i e s . A l t h o u g h t h e s e r e p o r t e d v a l u e s do n o t r e f l e c t t h e ra n g e and p o s s i b l e c o m b i n a t i o n s of f o r m a t i o n d e p t h s and p r e s s u r e r e g i m e s , t h e mean d e p t h s o f f o r m a t i o n a r e u s e d f o r t h e p u r p o s e s of an e x p l o r a t i o n m o d el, where a c t u a l d e p t h s o f f o r m a t i o n from t h e p a l e o s u r f a c e a r e not as i m p o r t a n t a s t h e r e l a t i v e d e p t h s o f f o r m a t i o n o f t h e two d e p o s i t s . N o t e , however, t h a t t h e c a l c u l a t e d f o r m a t i o n d e p t h o f 115 m f o r t h e Moosehorn d e p o s i t , b a s e d on f l u i d i n c l u s i o n a n a l y s e s , f a l l s w i t h i n t h e ra n g e of e s t i m a t e s b a s e d on s t r a t i g r a p h i c c r i t e r i a . S e c o n d a r y i n c l u s i o n s i n a m e t h y s t from b o t h Moosehorn and Mt. G r a v e s would have formed w i t h i n a s y s t e m t h a t was f r e e l y c o n n e c t e d t o t h e s u r f a c e , under h y d r o s t a t i c p r e s s u r e s a t a p p r o x i m a t e l y t h e same d e p t h s as t h e p r i m a r y i n c l u s i o n s . The open, vuggy c h a r a c t e r o f p o s t - o r e a m e t h y s t and c a l c i t e i s s u g g e s t i v e of d e p o s i t i o n f r o m f l u i d s t h a t f r e e l y c i r c u l a t e d t o t h e s u r f a c e . D e p t h s of f o r m a t i o n f o r c a l c i t e a t M o o s e h o r n , under t h e s e p r e s s u r e s do n o t a p p e a r t o be i n aggreement w i t h t h e s e c o n d a r y i n c l u s i o n e s t i m a t e s , p o s s i b l y i n d i c a t i n g p o s t - t r a p p i n g c h a n g e s of f l u i d i n c l u s i o n c h a r a c t e r a s a r e s u l t of l e a k a g e o r n e c k i n g down. C a l c i t e i s t y p i f i e d by l a t e d e p o s i t i o n i n t h e p a r a g e n e t i c s e q u e n c e of m i n e r a l i z a t i o n . T h e r e f o r e , i t i s a l s o p o s s i b l e t h a t c a l c i t e d e p o s i t i o n o c c u r e d a f t e r f a u l t i n g and e r o s i o n had removed some of t h e g e o l o g i c c o v e r . A model f o r t h e f o r m a t i o n o f Toodoggone e p i t h e r m a l g o l d and s i l v e r d e p o s i t s must t a k e i n t o a c c o u n t v a r i a t i o n s i n s a l i n i t y , t e m p e r a t u r e , d e p t h o f f o r m a t i o n , a l t e r a t i o n t y p e s , and m e t a l z o n a t i o n as w e l l a s d e p o s i t i o n a l mechanisms. The p r o p o s e d s e l f - s e a l e d t h r o t t l i n g model a c c o u n t s f o r t h e d i f f e r e n c e i n d e p t h s of f o r m a t i o n o f t h e Moosehorn and Mt G r a v e s p r o s p e c t s as w e l l a s t h e d i f f e r e n c e i n d e p t h s of f o r m a t i o n o f s e c o n d a r y i n c l u s i o n s . As i n d i c a t e d by t h e f l u i d i n c l u s i o n d a t a o r e - m i n e r a l d e p o s i t i o n a t b o t h t h e Mt. G r a v e s and Moosehorn d e p o s i t s o c c u r r e d under t h e e f f e c t s of l i t h o s t a t i c p r e s s u r e s below a t h r o t t l e p o i n t ( F i g u r e 5 - 7 ) . S e l f - s e a l i n g of h y d r o t h e r m a l s y s t e m s t h r o u g h m i n e r a l d e p o s i t i o n has been p o s t u l a t e d by numerous a u t h o r s i n o r d e r t o e x p l a i n t h e d e v e l o p m e n t o f p r e s s u r e s t h a t a p p r o a c h l i t h o s t a t i c m a g n i t u d e s (Buchanan, 1981). The Moosehorn and Mt. G r a v e s d e p o s i t s may have fo r m e d b e n e a t h s u c h a s e a l e d s y s t e m . When t h e c a p i s f r a c t u r e d , and t h e e x c e s s p r e s s u r e r e l e a s e d , s o l u t i o n s w i l l b o i l a t a much g r e a t e r d e p t h t h a n would be e x p e c t e d under s t r i c t l y h y d r o s t a t i c c o n d i t i o n s . D e p o s i t i o n o f o r e m i n e r a l s i n t h e Mt. G r a v e s d e p o s i t may have o c c u r e d i n r e s p o n s e t o s u c h a p r e s s u r e r e l e a s e . G r a d u a l l y , p r e s s u r e s on t h e s y s t e m would a p p r o a c h h y d r o s t a t i c m a g n i t u d e s , y w i t h s e c o n d a r y i n c l u s i o n s f r o m Mt. G r a v e s and Moosehorn f o r m i n g from s o l u t i o n s t h a t f r e e l y c i r c u l a t e d t o t h e s u r f a c e , under t h e s e p r e s s u r e s . E p i s o d i c s e a l i n g and f r a c t u r i n g of h y d r o t h e r m a l s y s t e m s i s e v i d e n t i n many e p i t h e r m a l g o l d d i s t i c t s , a nd p l a y s an i m p o r t a n t r o l e i n d e t e r m i n i n g t h e d e p t h s a t w h i c h m i n e r a l d e p o s i t i o n o c c u r s (Buchanan, 1981; B e r g e r and Eimon, 1983). C o o l i n g of h y d r o t h e r m a l f l u i d s c a n be a c h i e v e d by a v a r i e t y of mechanisms. In t h e t e m p e r a t u r e of f o r m a t i o n r a n g e i n d i c a t e d f o r p r i m a r y i n c l u s i o n s (232°C t o 267°C) i t i s u n l i k e l y t h a t a p p r e c i a b l e amounts of c o o l i n g w i l l be a c h i e v e d t h r o u g h i r r e v e r s i b l e a d i a b a t i c e x p l a n s i o n ( B a r t o n and T o u l m i n , 1961). However, c o o l i n g o f f l u i d s by g r o u n d w a t e r m i x i n g i s " o v e r w h e l m i n g l y l i k e l y " i n h y d r o t h e r m a l systems ( B a r t o n and T o u l m i n i n B a r n e s , 1967). T h i s p r o c e s s would e x p l a i n t h e l o w e r s a l i n i t i e s and t e m p e r a t u r e s o b s e r v e d i n p r i m a r y f l u i d i n c l u s i o n s f r o m t h e Moosehorn p r o s p e c t . As w e l l , s i n c e t h e s o l u b i l i t y o f g o l d d e c r e a s e s r a p i d l y below 250°C and w i t h d e c r e a s i n g s a l i n i t i e s ( H e l g e s o n and G a r r e l s , 1968) g o l d g r a d e s would be e x p e c t e d t o d e c r e a s e w i t h i n c r e a s e d g r o u n d w a t e r i n f l u x , as o b s e r v e d i n t h e Moosehorn v e i n s ( F i g u r e 5 - 7 ) . A l t h o u g h not a p p a r e n t i n t h e s t u d i e d p r o p e c t s , s i l v e r v a l u e s m i g h t be e x p e c t e d t o i n c r e a s e w i t h d e c r e a s e d s a l i n i t y and l o w e r t e m p e r a t u r e s (Watson, 1981). The o b s e r v e d d e c l i n e i n t e m p e r a t u r e r e g i m e between o r e d e p o s i t i o n and s e c o n d a r y i n c l u s i o n f o r m a t i o n c o u l d be e x p l a i n e d by an i n c r e a s e i n c o n v e c t i o n p r o c e s s e s , l e a d i n g t o a g r e a t e r m i x i n g of c o o l e r g r o u n d w a t e r w i t h t h e r i s i n g h y d r o t h e r m a l f l u i d s . D u r i n g p e r i o d s when h y d r o s t a t i c p r e s s u r e s p r e v a i l e d , s u c h as when s e c o n d a r y i n c l u s i o n s f ormed, i t would be l i k e l y t h a t m i x i n g would p r o c e e d a t a g r e a t e r r a t e t h a n when l i t h o s t a t i c p r e s s u r e s were a c t i n g on th e f l u i d s . M e t a l z o n a t i o n w i t h i n e p i t h e r m a l d e p o s i t s c an be e x p l a i n e d by u s i n g t h e mechanism o f b o i l i n g h y d r o t h e r m a l f l u i d s . Base m e t a l s a r e d e p o s i t e d a t h i g h e r t e m p e r a t u r e s 145 t h a n p r e c i o u s m e t a l s ; w i t h base m e t a l v a l u e s d e c r e a s i n g w i t h i n c r e a s e d p r e c i o u s m e t a l v a l u e s , as h i g h e r l e v e l s o f t h e s y s t e m a r e r e a c h e d (Buchanan, 1981). B o i l i n g g e n e r a l l y o c c u r s n e a r t h e t o p of t h e b a s e m e t a l h o r i z o n , i n a h i g h l y m i n e r a l i z e d zone of mixed p r e c i o u s and b a s e m e t a l s (Buchanan, 1981). The Mt. G r a v e s p r o s p e c t would have p r o b b l y formed i n t h i s mixed zone, a s i s i n d i c a t e d by t h e p r e s e n c e of f l u i d i n c l u s i o n b o i l i n g t e x t u r e s , and t h e o c c u r r e n c e o f g a l e n a and s p h a l e r i t e , as w e l l as g o l d and s i l v e r . The Moosehorn p r o s p e c t was formed a t much h i g h e r l e v e l s i n t h e s y s t e m , and t h e r e f o r e base m e t a l m i n e r a l i z a t i o n would n o t be e x p e c t e d . T r a n s p o r t and p r e c i p i t a t i o n of g o l d and s i l v e r c an a l s o be e x p l a i n e d by t h e mechanism o f b o i l i n g . In low s a l i n e s o l u t i o n s below 350°C, g o l d i s l i k e l y t r a n s p o r t e d i n b i s u l f i d e t h i o c o m p l e x e s ( i e . A u ( H S ) 2 , L e w i s , 1982 and Seward, 1972). B o i l i n g c a u s e s C 0 2 and H 2S t o be p a r t i t i o n e d i n t o " t h e v a p o u r p h a s e , p r o d u c i n g a r i s e i n t h e a c t i v i t i e s of S~and HS i n t h e r e m a i n i n g s o l u t i o n , l e a d i n g t o t h e f o r m a t i o n of g o l d and s i l v e r t h i o c o m p l e x e s (Buchanan, 1981). H i g h oxygen f u g a c i t i e s c a u s e t h e breakdown o f t h e s e g o l d / s i l v e r s u l f i d e and b i s u l f i d e t h i o c o m p l e x e s l e a d i n g t o t h e p r e c i p i t a t i o n o f p r e c i o u s m e t a l s . The abundance of r e a c t a n t o x i d i z i n g a g e n t s s u c h as h e m a t i t e and manganese o x i d e w i t h i n b o t h t h e Mt. G r a v e s and Moosehorn p r o s p e c t s , m i g h t c a u s e an i n c r e a s e i n oxygen f u g a c i t i e s upon a t t a c k by a c i d i c s o l u t i o n s and t h u s c a u s e t h e l o c a l i z a t i o n o f g o l d and s i l v e r m i n e r a l i z a t i o n w i t h i n t h e s e z o n e s . P r e c i o u s m e t a l 146 m i n e r a l i z a t i o n m i g h t be e x p e c t e d t o o c c u r a l o n g v o l c a n i c f l o w c o n t a c t s where t h e r e i s an abundance o f o x i d e m i n e r a l s , p r o d u c e d as a r e s u l t o f w e a t h e r i n g ( i e . M o o s e h o r n ) . C o o l i n g of h y d r o t h e r m a l f l u i d s t h r o u g h an i n f l u x o f low t e m p e r a t u r e , low s a l i n e m e t e o r i c water may have been r e s p o n s i b l e f o r t h e d e p o s i t i o n of gangue and o r e m i n e r a l s w i t h i n t h e Moosehorn d e p o s i t . At t h e d e p t h s i n d i c a t e d by t h e Mt. G r a v e s p r i m a r y i n c l u s i o n s , g r o u n d w a t e r m i x i n g would p r o b a b l y be of l e s s i m p o r t a n c e , w i t h b o i l i n g b e i n g t h e most l i k e l y mechanism f o r m i n e r a l d e p o s i t i o n . A l t e r a t i o n p a t t e r n s can a l s o p a r t i a l l y be a t t r i b u t e d t o t h e e f f e c t s of b o i l i n g . As m e n t i o n e d a b o v e , C 0 2 and H 2S a r e s e l e c t i v e l y p a r t i t i o n e d i n t o t h e v a p o u r phase upon b o i l i n g . As t h e s e v a p o u r s r i s e t o t h e s u r f a c e , t h e y c o o l and c o n d e n s e t o f o r m low p H ' w a t e r s . The r e s u l t i n g a c i d s o l u t i o n s a t t a c k s i l i c a t e m i n e r a l s , a l t e r i n g them t o c l a y s and a l u n i t e , f o r m i n g a low pH c a p o v e r t h e h y d r o t h e r m a l s y s t e m ( F i g u r e 5 - 8 ) . B o i l i n g l e v e l s can change i n r e s p o n s e t o a change i n h y d r o s t a t i c and l i t h o s t a t i c p r e s s u r e s and t h u s o v e r p r i n t i n g o f a l t e r a t i o n s can o c c u r . The p r o p o s e d model f o r t h e f o r m a t i o n o f t h e Moosehorn and Mt. G r a v e s g o l d and s i l v e r d e p o s i t s i s d e p i c t e d i n F i g u r e : 5-7. A t h r o t t l e o r c o n s t r i c t i o n a t a d e p t h of l e s s t h a n 100 m c a u s e d Moosehorn v e i n s t o form from low s a l i n e , m oderate t e m p e r a t u r e f l u i d s under l i t h o s t a t i c p r e s s u r e s . B o i l i n g of h y d r o t h e r m a l f l u i d s i n r e s p o n s e t o f r a c t u r i n g of t h e s e a l e d c a p and r e l e a s e o f e x c e s s p r e s s u r e s , l e d t o t h e p r e c i p i t a t i o n of base and p r e c i o u s m e t a l s w i t h i n t h e Mt. 14 7 G r a v e s v e i n s . C o n s e q u e n c e s o f t h e P r o p o s e d M o d e l By a p p l y i n g t h i s model as an e x p l o r a t i o n t o o l w i t h i n t h e Toodoggone a r e a , g e o l o g i s t s c a n e s t i m a t e a t what l e v e l w i t h i n t h e s y s t e m s p e c i f i c p r o s p e c t s o c c u r , and t h u s d e c i d e whether o r n o t g o l d and s i l v e r v a l u e s can be e x p e c t e d t o i n c e a s e w i t h d e p t h . F o r example, t h e Moosehorn Amethyst B r e c c i a zone a p p e a r s t o have t h e p o t e n t i a l o f i n c r e a s i n g p r e c i o u s m e t a l s w i t h d e p t h , whereas t h e model i n d i c a t e s t h a t i n t h e Mt. G r a v e s p r o s p e c t , g o l d and s i l v e r v a l u e s may d e c r e a s e as base m e t a l v a l u e s i n c r e a s e w i t h d e p t h . The S i l v e r p o n d and GWP 1 t o 10 p r o p e r t i e s r e p r e s e n t t h e low pH c a p p i n g z o n e s d e p i c t e d i n F i g u r e 5-8. T h e r e a p p e a r s t o be p o t e n t i a l f o r e n c o u n t e r i n g p r e c i o u s m e t a l m i n e r a l i z a t i o n a t d e p t h , below t h e s e z o n e s . I t s h o u l d be m e n t i o n e d however t h a t t h e s e s y s t e m s do no n e c e s s a r i l y have t o be v e r t i c a l i n t h e i r o r i e n t a t i o n and t h e r e f o r e , s i m p l e v e r t i c a l d r i l l i n g on t h e s e low pH a l t e r a t i o n c a p s w i l l not n e c e s s a r i l y i n t e r s e c t t h e o r e - z o n e , i f one e x i s t s a t a l l . The L a w y e r s and C l i f f C r e e k d e p o s i t s p r o b a b l y o c c u r below t h e Moosehorn p r o s p e c t i n t h e e x p l o r a t i o n model, w i t h i n t h e p r e c i o u s m e t a l h o r i z o n . V e r y few base m e t a l s a r e e v i d e n t w i t h i n t h e s e z o n e s and t h e r e f o r e t h e s e d e p o s i t s w ould be l o c a t e d above t h e Mt. G r a v e s p r o s p e c t on F i g u r e 5-8. The Baker mine, w i t h i t s h i g h base m e t a l c o n t e n t would p r o b a b l y o c c u r j u s t below t h e Mt G r a v e s zone i n t h e e x p l o r a t i o n m odel. P r e c i o u s m e t a l g r a d e s a r e much h i g h e r i n 14 3 HYDROTHERMAL ALTERATION A S S E M B L A G E S FIGURE 5-8 ffil INTERMEDIATE TO ADVANCED ARGILLIC kaolinite, montmorillonite, illite, dickite, alunite, fluorite | [ SILICIC (INCLUDES SINTER) amethystine, chalcedonic, jasperoidal and milky quartz, barite, hematite, manganese oxide POTASSIC adularia, orthoclase, biotite, calcite, sericite PROPYLITIC epidote, chlorite, sericite, carbonate, pyrite ZEOLITIC laumontite, natrolite, calcite 149 FIGURE 5-8: Depth o f f o r m a t i o n and a l t e r a t i o n z o n i n g o f Toodoggone R i v e r , g o l d and s i l v e r d e p o s i t s . 150 t h e v e i n s a t t h e Baker mine t h a n a t Mt. G r a v e s , p o s s i b l y i n d i c a t i n g t h e e x i s t e n c e of more t h a n one h y d r o t h e r m a l s y s t e m a t t h e t i m e o f m i n e r a l i z a t i o n w i t h i n t h e Toodoggone R i v e r r e g i o n . The s t y l e and t y p e of m i n e r a l i z a t i o n on t h e G o l d e n N e i g h b o u r p r o p e r t y does n o t a p p e a r t o f i t t h e p r o p o s e d model as i n d i c a t e d by t h e p r e s e n c e o f base m e t a l s as w e l l as m o l y b d e n i t e and s c h e e l i t e m i n e r a l i z a t i o n w i t h i n an i n t e n s e a r g i l l i c a l t e r a t i o n h a l o . V e i n c h a r a c t e r and m i n e r a l o g y s u g g e s t t h a t t h i s t y p e of m i n e r a l i z a t i o n may have formed i n a p o r p h y r y e n v i r o n m e n t , r a t h e r t h a n a t t h e d e p t h s and t e m p e r a t u r e s i n d i c a t i v e o f e p i t h e r m a l f o r m a t i o n . 5.4 E p i t h e r m a l P r e c i o u s M e t a l D i s t r i c t s of N o r t h A m e r i c a P r o s p e c t s and d e p o s i t s s i m i l a r t o t h o s e of t h e Toodoggone R i v e r a r e a o c c u r i n B r i t i s h C o l u m b i a , t h e w e s t e r n U n i t e d S t a t e s and M e x i c o . B e f o r e t h e d i s c o v e r y of t h e Toodoggone camp, e p i t h e r m a l p r e c i o u s and b a s e m e t a l e x p l o r a t i o n was c e n t e r e d on t h e S t e w a r t a r e a of n o r t h - c e n t r a l B r i t i s h C o l u m b i a ( S c h r o e t e r , 1983). The P r e m i e r , B i g M i s s o u r i and D o l l y V a r d e n - T o r b r i t mines n e a r S t e w a r t have combined t o p r o d u c e o v e r 1.7 m i l l i o n kg of s i l v e r , 51,000 kg of g o l d and 4 m i l l i o n kg o f l e a d o v e r t h e p a s t 75 y e a r s . More r e c e n t l y a number of p r e c i o u s m e t a l p r o s p e c t s have been l o c a t e d w i t h i n t h e S t e w a r t Camp, i n c l u d i n g t h e M i t c h e l l - S u l p h u r e t s p r o p e r t y . The above d e p o s i t s a r e c l a s s i f i e d as " h i g h - l e v e l " p r e c i o u s and base m e t a l o c c u r r e n c e s ( S c h r o e t e r , 1983), and a r e p r o b a b l y of 151 e p i t h e r m a l o r i g i n . In t h e S t e w a r t a r e a p r e c i o u s and base m e t a l m i n e r a l i z a t i o n o c c u r s w i t h i n E a r l y J u r a s i c H a z e l t o n v o l c a n i c f l o w s , p y r o c l a s t i c s and s e d i m e n t a r y s e q u e n c e s . M i n e r a l i z e d z o n e s show t y p i c a l e p i t h e r m a l c h a r a c t e r i s t i c s i n c l u d i n g s t o c k w o r k and s i l i c i f i e d z o n e s and vuggy, open space f i l l i n g t e x t u r e s as can be seen i n t h e Toodoggone d e p o s i t s . M i n e r a l i z a t i o n i s r e l a t e d t o t h e i n t r u s i o n o f e a r l y J u r a s s i c s t o c k s , and c o n s i s t s of g a l e n a , s p h a l e r i t e , t e t r a h e d r i t e , e l e c t r u m , p o l y b a s i t e , g o l d , s i l v e r and a c a n t h i t e ( B a r r , 1978). A l t e r a t i o n s t y l e s a r e a l s o s i m i l a r t o t h e Toodoggone r e g i o n , a l t h o u g h t h e y t e n d t o be l e s s p r o n o u n c e d . The C i n o l a p r e c i o u s m e t a l s d e p o s i t i n t h e Queen C h a r l o t t e I s l a n d s a l s o has c h a r a c t e r i s t i c s s i m i l a r t o t h e Toodoggone R i v e r d e p o s i t s , a l t h o u g h t h e m i n e r a l i z a t i o n i s M i o c e n e , not J u r a s s i c . M i o c e n e s h a l e s and e l a s t i c s have, been i n t r u d e d by r h y o l i t i c s t o c k s o f s i m i l a r age, r e s u l t i n g i n t h e l o c a l i z a t i o n of p r e c i o u s m e t a l m i n e r a l i z a t i o n w i t h i n s t o c k w o r k and s i l i c i f i e d z o n e s . A l t h o u g h o f e p i t h e r m a l o r i g i n , t h i s d e p o s i t i s t h o u g h t t o be of t h e C a r l i n v a r i e t y , and n o t of t h e Toodoggone s t y l e ( B a r r , 1978). O t h e r a r e a s o f B r i t i s h C o l u m b i a w h i c h have m i n e r a l o c c u r r e n c e s s i m i l a r t o t h o s e o f t h e Toodoggone Camp i n c l u d e t h e a r e a s o u t h of V a n d e r h o o f (Le. Capoose S i l v e r P r o s p e c t ) and t h e H a r r i s o n Lake r e g i o n n e a r V a n c o u v e r ( S c h r o e t e r , 1981; Ray, 1983). As d e f i n e d above, p r e c i o u s m e t a l m i n e r a l i z a t i o n o c c u r s i n E a r l y J u r a s s i c v o l c a n i c s , and i s t y p i c a l o f e p i t h e r m a l d e p o s i t s i n t h e Toodoggone and S t e w a r t 152 Camps. In B r i t i s h C o l u m b i a , e p i t h e r m a l p r e c i o u s m e t a l m i n e r a l i z a t i o n has been d i s c o v e r e d p r e d o m i n a n t l y i n the* J u r a s s i c H a z e l t o n v o l c a n i c s . T h i s o b s e r v a t i o n i s p r o b a b l y due t o t h e i n t e n s e l e v e l o f e x p l o r a t i o n t h a t t h i s g r o u p of r o c k s has u ndergone i n r e c e n t y e a r s . The Toodoggone v o l c a n i c s have now been r e c o g n i z e d as an i m p o r t a n t h o s t t o s i m i l a r p r e c i o u s m e t a l d e p o s i t s . In r e c e n t y e a r s t h e Toodoggone v o l c a n i c s have s u p e r c e d e d t h e H a z e l t o n Group, as f a v o u r e d h o s t r o c k s f o r s h a l l o w , low t e m p e r a t u r e p r e c i o u s m e t a l m i n e r a l i z a t i o n i n B r i t i s h C o l u m b i a . The m a j o r i t y of c l a s s i c p r e c i o u s m e t a l d e p o s i t s on w h i c h most e p i t h e r m a l e x p l o r a t i o n models a r e b a s e d o c c u r i n t h e w e s t e r n U n i t e d S t a t e s and M e x i c o . U n l i k e d e p o s i t s i n B.C w h i c h g e n e r a l l y o c c u r w i t h i n t h e o u t e r a r c - a c c r e t i o n a r y p r i s m s e t t i n g , t h e s e d e p o s i t s c o i n c i d e w i t h t h e a d j a c e n t magma a r c - b a c k a r c r e g i o n s of c o n v e r g e n t p l a t e b o u n d a r i e s ( G i l e s and N e l s o n , 1982). T e c t o n i c e n v i r o n m e n t and age o f m i n e r a l i z a t i o n a r e t h e main c r i t e r i a f o r d i s t i n g u i s h i n g Toodoggone s t y l e m i n e r a l i z a t i o n f r o m e p i t h e r m a l d e p o s i t s i n t h e U n i t e d S t a t e s and M e x i c o . T a b l e 5-2 l i s t s t h e main c h a r a c t e r i s t i c s of f i v e e p i t h e r m a l p r e c i o u s m e t a l d i s t r i c t s as w e l l as t h e Toodoggone R i v e r a r e a of B.C. E p i t h e r m a l g o l d and s i l v e r d e p o s i t s o c c u r i n g r e a t a bundance i n C o l o r a d o , Nevada, A r i z o n a , New M e x i c o and C a l i f o r n i a . U n l i k e Toodoggone d e p o s i t s w h i c h o c c u r m a i n l y i n a n d e s i t e s , d e p o s i t s i n t h e w e s t e r n U.S.A o c c u r i n a v a r i e t y o f v o l c a n i c r o c k s i n c l u d i n g r h y o l i t e s , l a t i t e s , TABLE 5-2: Selected Epithermal Gold-Silver D i s t r i c t s i n N. America D i s t r i c t Major Hosts Ore Age M i n e r a l o g y of V e i n 1 A l t e r a t i o n A s s e m b l a g e s P r o p y l . Potass. A r g i l . P h y l l . A l u n i t . S i l i c . Toodoggone B r i t i s h Columbia Early Jurassic Trachytetuff Andesite Tuff 190 my AM, QZ, AD, CA HE, AU, AG, EL CC, PL, PY, AC TE, CP, GN, SP BA, PR, SC Yes Yes Yes No Yes Yes Creede Colorado Oligocene Andesite and Rhyolite Tuff . Oligocene AD, QZ, CA, BA CH, SE, AN, FL SI, GN, SP, AG, PY, RC, TE, PA AM, AC Yes- Yes Yes Yes Yes Yes D i s t r i c t E v i d e n c e of B o i l i n s 3 S a l i n -i t y 4 o 5 Th C V e r t i c Z o n i n g 6 V e i n A t t J Max V e i n W. 8 Au : Ag V e r t . Ore Ex. 9 low p H Cap Ore Sh. F l a t . B . F i n e Gr Qua r t z F l u i d In . D . Toodoggone B r i t i s h Columbia Yes alunite Clays Yes Yes 0.4-7.8 230 to 265 Base Metals Increase With Depth NNW 80-90°N NNE 80-90°N 25 1:20 approx. 150 Creede Colorado Yes i l l i t e Yes No Yes ? 250° Base Metals Increase With Depth N-S to N40W 40-80 °S, ? 1:400 310 D i s t r i c t Major Hosts Ore Age Mineralogy of V e i n 1 A l t e r a t i o n Assemblages Propyl. Potass. A r g i l . P h y l l . A l u n i t . S i l i c . Tayoltita, Durango, Mexico Tertiary andesite flows Oligocene AD, QZ, CA, CH SP, RB, EL, AU AG, PY, CP, GN, SR, AC Yes Yes ? ? Yes Cornstock, Storey Co., Nevada Miocene Andesites 13.7 to 12.6 my AD, QZ, CA, RB AU, PY, CP, GN SP, RC, RS, S~N PL, AC Yes No Yes Yes Yes Yes D i s t r i c t Evidence of B o i l i n e 3 S a l i n -ity. 4 Th °C5 V e r t i c. Zoning 6 Vein Att .7 Max Vein W. 8 Au : Ag Vert . Ore Ex. 9 low pH Cap Ore Sh. F l a t . B . Fine Gr Quart z F l u i d In . D . Tayoltita, Durango, Mexico No Yes Yes Yes 3.3 to 8.4 265 Base Metals Increase With Depth NlOW 65-85E 15 1:51 600 Comstock Storey Co. Nevada Yes clays Yes Yes 250 to 300 None NNE 45E AVE. 2.5 to 4.2 1:23 to 1:40 610 D i s t r i c t Major Hosts Ore Age M i n e r a l o g y of V e i n 1 A l t e r a t i o n A s s e m b l a g e s 2 P r o p y l . Potass. A r g i l . P h y l l . A l u n i t. S i 1 i c. G o l d f i e l d Nevada Miocene Dacite and Andesite 21.0 my QZ, SE, KA, RB AU, PY, FA, TE BA, GO, AL, TL Yes No Yes Yes Yes Yes Eureka D i s t . San Juan Co. Colorado Ter t i a r y Quartz L a t i t e Tuff 13-16 my AD, QZ, AU, RB AG, RC, RS, TE F l , AG, SP, GN PY, TL, AM Yes. ? Yes Yes No Yes D i s t r i c t E v i d e n c e o f B o i l i n g 3 S a l i n -i t y 4 Th °C5 V e r t i c. Z o n i n g 6 V e i n A t t J Max V e i n W. 8 Au : Ag V e r t . Ore Ex. 9 low pH Cap Ore Sh. F l a t . B . F i n e Gr Qua r t z F l u i d I n . D. Go l d f i e l d Nevada Yes alunite clays Yes Yes Yes ? 200 to 300°C Base Metals Increase With Depth . NSTONW Hor i -zontal to l/ertica] 55 3:1 305 Eureka D i s t . San Juan Co. Colorado Yes Yes No 0.8 285 to 293 Base Metals Increase With Depth NSOE N60W 1.0 1:47 610 F o o t n o t e s f o r TABLE 5-2 1. M i n e r a l a b b r e v i a t i o n s a r e : AD - a d u l a r i a GN - g a l e n a AG - s i l v e r HM - h e m a t i t e AM - amethyst PA - p y r a r g y r i t e AN - a n k e r i t e PL - p o l y b a s i t e AC - a c a n t h i t e PR - p r o u s t i t e AU - g o l d PY - p y r i t e BA - b a r i t e QZ - q u a r t z CA - c a l c i t e RB - ruby s i l v e r s CC - c h a l c e d u n y RC - r h o d o c h r o s i t e CH - c h l o r i t e SC - s p e c u l a r i t e EL - e l e c t r u m SI - s i d e r i t e FL - f l u o r i t e SP - s p h a l e r i t e GO - g o l d f i e l d i t e TE - t e t r a h e d r i t e 2. A l t e r a t i o n a b b r e v i a t i o n s a r e : P r o p y l . - p r o p y l i t i c P h y l l . - p h y l l i c P o t a s s . - p o t a s s i c A l u n i t . - a l u n i t i c A r g i l . - a r g i l l i c S i l i c . - s i l i c i c 3. E v i d e n c e o f b o i l i n g a b b r e v i a t i o n s a r e : Ore Sh. F l a t B. - Ore shoot f l a t bottomed F i n e Gr. Quartz - F i n e g r a i n e d q u a r t z F l u i d I n . D. - F l u i d i n c l u s i o n d a t a 4. E x p r e s s e d as e q u i v a l e n t w e i g h t p e r c e n t N a C l . 5. Th - temp e r a t u r e o f h o m o g e n i z a t i o n 6. V e r t i c . Z o ning - V e r t i c a l z o n i n g 7. V e i n A t t . - V e i n a t t i t u d e 8. Max V e i n W. - Max v e i n w i d t h i n m e t r e s . 9. V e r t . Ore Ex. - V e r t i c a l o r e e x t e n t i n met r e s . 10. A l l d a t a e x c e p t f o r Toodoggone d i s t r i c t a r e from Buchanan (.1981) . 157 d a c i t e s and a n d e s i t e s , w i t h r h y o d a c i t e b e i n g t h e most t y p i c a l h o s t r o c k ( H e a l d - W e t l a u f e r e t al., 1983). M i n e r a l i z a t i o n i s g e n e r a l l y c o n t e m p o r a n e o u s w i t h h o s t r o c k d e p o s i t i o n ; w i t h a T e r t i a r y age f o r b o t h b e i n g most common ( T a b l e 5 - 2 ) . G o l d / s i l v e r r a t i o s r ange f r o m 1:400 a t C r e e d e t o 3:1 a t G o l d f i e l d , d e p e n d i n g on t h e t y p e of h y d r o t h e r m a l s y s t e m , s o u r c e r o c k s , and l e v e l of e x p o s u r e . A l t e r a t i o n p a t t e r n s a r e s i m i l a r i n s t y l e , m i n e r a l o g y and d i s t r i b u t i o n t o t h o s e of t h e Toodoggone R i v e r d e p o s i t s w i t h p r o p y l i t i c , a r g i l l i c , s i l i c i c and p o t a s s i c f a c i e s b e i n g most common. The C r e e d e d e p o s i t s i n C o l o r a d o have an a l t e r a t i o n h a l o s i m i l a r t o t h e Toodoggone d e p o s i t s w i t h s i l i c i c and p o t a s s i c a l t e r a t i o n g r a d i n g o u t w a r d i n t o a r g i l l i c and p r o p y l i t i c z o n e s . B o t h o r e and gangue m i n e r a l o g y a r e v a r i a b l e i n t h e s e d e p o s i t s w i t h a m e t h y s t , a d u l a r i a , c h a l c e d o n y , p y r i t e , a c a n t h i t e and g o l d o c c u r i n g most f r e q u e n t l y (Buchanan, 1981). V e i n m i n e r a l o g y i s d i r e c t l y r e l a t e d t o t h e l e v e l o f e x p o s u r e w i t h i n t h e h y d r o t h e r m a l s y s t e m . M e t a l z o n a t i o n u s u a l l y i s e v i d e n t , w i t h p r e c i o u s m e t a l v a l u e s d e c r e a s i n g w i t h d e p t h , w h i l e base m e t a l v a l u e s i n c r e a s e . T e m p e r a t u r e s of m i n e r a l d e p o s i t i o n r a n g e from 140°C t o 325°C w i t h i n t h e s e d e p o s i t s , w i t h s a l i n i t i e s g e n e r a l l y g r o u p i n g between 0 and 13 e q u i v a l e n t w e i g h t p e r c e n t N a C l ( H e a l d - W e t l a u f e r e t a l . , 1983). F l u i d i n c l u s i o n d a t a f r o m t h e Toodoggone r e g i o n f a l l r o u g h l y w i t h i n t h e c e n t e r o f t h e s e d i s t r i b u t i o n s . B o i l i n g i s an e f f e c t i v e p r e c i p i t a t i o n mechanism w i t h e v i d e n c e f o r b o i l i n g b e i n g r e c o g n i z a b l e i n 158 most o f t h e e p i t h e r m a l d i s t r i c t s i n t h e U n i t e d S t a t e s . As i s e v i d e n t , Toodoggone e p i t h e r m a l p r e c i o u s m e t a l d e p o s i t s e x h i b i t s i m i l a r m o r p h o l o g i c a l and m i n e r a l o g i c a l c h a r a c t e r i s t i c s t o t h e c l a s s i c e p i t h e r m a l d i s t r i c t s of t h e w e s t e r n U n i t e d S t a t e s and M e x i c o ; t h e o n l y d i f f e r e n c e b e i n g t h a t Toodoggone d e p o s i t s a r e J u r a s s i c and n o t T e r t i a r y . R e l a t i v e l y few E a r l y J u r a s s i c e p i t h e r m a l p r e c i o u s m e t a l d i s t r i c t s have s u r v i v e d 180 m i l l i o n y e a r s o f u p l i f t and e r o s i o n , making t h e Toodoggone R i v e r Camp an anomaly among p r e c i o u s m e t a l d i s t r i c t s . 159 A s h l e y , R.P., and Keith., W.J. 1976. D i s t r i b u t i o n o f g o l d and o t h e r elements i n s i l i c i f i e d r o c k s o f t h e g o l d f i e l d m i n i n g d i s t r i c t , Nevada. G e o l o g i c a l S o c i e t y o f A m e r i c a , P r o -f e s s i o n a l P a p e r , no. 843-B, 17p. B a r n e s , H.L. (ed.). 19 67. G e o c h e m i s t r y of h y d r o t h e r m a l ore d e p o s i t s . H o l t , R i n e h a r t and Winston I n c . , New; Y o r k , 670p. B a r n e s , H.L. (ed.). 1979. G e o c h e m i s t r y o f h y d r o t h e r m a l o r e d e p o s i t s , second e d i t i o n . John W i l e y and Sons I n c . , New Y o r k , 79 8p. B a r r , D.A. 1978. C h a p p e l l e g o l d - s i l v e r d e p o s i t , B r i t i s h . C olumbia. The Canadian I n s t i t u t e o f M i n i n g and M e t a l l u r g y , B u l l e t i n , V. 72, pp.66-79 B a r t o n , P.B., J r . , and T o u l m i n , P. 1961. Some mechanisms f o r c o o l i n g h y d r o t h e r m a l f l u i d s . U n i t e d S t a t e s G e o l o g i c a l S u r v e y , P r o f e s s i o n a l Paper no. 424-D, pp.348-352. B a r r , D.A. 19 80. G o l d i n the Canadian c o r d i l l e r a . The Canadian I n s t i t u t e o f M i n i n g and M e t a l l u r g i c a l B u l l e t i n , V.73, pp.59-76. B e r g e r , B.R., and Eimon, P . I . 1983. C o n c e p t u a l models o f e p i t h e r m a l s i l v e r - g o l d d e p o s i t s . I n C o l l e c t i o n o f Un-p u b l i s h e d Papers on E p i t h e r m a l S i l v e r - G o l d D e p o s i t s by P a u l Eimon and O t h e r s . G e o l o g i c a l A s s o c i a t i o n o f Canada, 34p. Berman, R. 1979. The C o q u i h a l l a v o l c a n i c complex, s o u t h -w e s t e r n B r i t i s h Columbia. U n p u b l i s h e d M.Sc. t h e s i s , Department o f G e o l o g i c a l S c i e n c e s , U n i v e r s i t y o f B r i t i s h C o l u m b i a , 170p. B e s t , M.G. 1982. Igneous and metamorphic p e t r o l o g y . W.H. Freeman and Co., San F r a n c i s c o , 630p. Bloom, M.S. 1979. E v i d e n c e f o r magmatic-hydrothermal p r o -c e s s e s from f l u i d i n c l u s i o n s t u d i e s o f stockwork molybdenum d e p o s i t s . U n p u b l i s h e d Ph.D. T h e s i s , D e p a r t -ment o f G e o l o g i c a l S c i e n c e s , U n i v e r s i t y o f B r i t i s h C o lumbia. B o y l e , R.W. 1979. The g e o c h e m i s t r y of g o l d and i t s d e p o s i t s . G e o l o g i c a l Survey o f Canada, B u l l e t i n 280, 584p. Buchanan, L . J . 1981. P r e c i o u s m e t a l d e p o s i t s a s s o c i a t e d w i t h v o l c a n i c environments i n the southwest. I n R e l a t i o n o f T e c t o n i c s t o Ore D e p o s i t s i n t h e S o u t h e r n C o r d i l l e r a , D i c k i n s o n , W.R. , and Payne, W.D., eds., A r i z o n a G e o l o g i c a l S o c i e t y D i g e s t , V.16, 292p. 160 Burbank, W.S., and Leudke, R.G. 1969. Geology and ore d e p o s i t s o f t h e E u r e k a and a d j o i n i n g d i s t r i c t s San Juan M o u n t a i n s , C o l o r a d o . U n i t e d S t a t e s G e o l o g i c a l S u r v e y , P r o f e s s i o n a l P a p e r , no. 535, 73p. Cann, R.M. and Godwin, C.I. 1980. Geology and age o f the emess p o r p h y r y copper-molybdenum d e p o s i t , n o r t h - c e n t r a l B r i t i s h Columbia. Canadian I n s t i t u t e of M i n i n g and M e t a l l u r g y , B u l l e t i n , V.73, pp.94-99. C a r t e r , N.C. 1972. Toodoggone R i v e r a r e a . B.C. M i n i s t r y o f Energy, Mines and P e t r o l e u m R e s o u r c e s , GEM, 1971, pp. 63-70. Church, B.N. 19 74. Geology o f the S u s t u t a r e a . I n G e o l o g i c a l F i e l d w o r k 1974, B r i t i s h Columbia Department of Mines and P e t r o l e u m R e s o u r c e s , Paper 197 4-1, pp.51-55. Church, B.N. 1975. Geology o f the S u s t u t a r e a , In Geology, E x p l o r a t i o n and M i n i n g i n B r i t i s h C o l u m b i a , 1974, B r i t i s h C olumbia Department o f Mines and P e t r o l e u m R e s o u r c e s , Paper 1975-1, pp.305-309. C h r i s t i a n s e n , R.L. and O'Connor, J.T. 1966. A c o m p o s i t i o n a l l y zoned a s h - f l o w s h e e t i n South Nevada. U n i t e d S t a t e s G e o l o g i c a l S u r v e y , P r o f e s s i o n a l P a p e r , no. 524F, 47p. C o l l i n s , P.L.F. 1979. Gas h y d r a t e s i n C 0 2 ~ b e a r i n g f l u i d i n c l u s i o n s and t h e use o f f r e e z i n g d a t a f o r e s t i m a t i o n of s a l i n i t y . Economic Geology, V.74, pp.1435-1444. C o n d i e , K.C., V i l i j o e n , M.J., and K a b l e , E.J.D. 1977. E f f e c t s o f a l t e r a t i o n on element d i s t r i b u t i o n i n A r c h i a n T h o l e i -i t e s from the B a r b e r t o n Greenstone b e l t , South A f r i c a . C o n t r i b u t i o n s t o M i n e r a l o g y and P e t r o l o g y . V.64, pp.75-89 . Eimon, P. 1983. E x p l o r a t i o n f o r e p i t h e r m a l g o l d and s i l v e r d e p o s i t s : t h e e p i t h e r m a l model. In_ C o l l e c t i o n o f Un-p u b l i s h e d Papers on E p i t h e r m a l S i l v e r - G o l d D e p o s i t s by P a u l Eimon and O t h e r s . G e o l o g i c a l A s s o c i a t i o n o f Canada. 15p. Eimon, P . I . , and A n c t i l , R.J. 1983. E p i t h e r m a l p r e c i o u s m e t a l s d e p o s i t s . I n C o l l e c t i o n o f U n p u b l i s h e d Papers on E p i t h e r m a l S i l v e r - G o l d D e p o s i t s by P a u l Eimon and O t h e r s . G e o l o g i c a l A s s o c i a t i o n o f Canada. 17p. E i s b a c h e r , G.H. 1971. A s u b d i v i s i o n o f t h e Upper C r e t a c e o u s -Lower T e r t i a r y S u s t u t Group, Toodoggone map-area, B r i t i s h C o l umbia. G e o l o g i c a l Survey of Canada, Paper 70-68, 16p. 161 Erdman, L. 1978. P e t r o l o g y , g e o c h r o n o l o g y and g e o c h e m i s t r y o f J u r a s s i c V o l c a n i c and g r a n i t i c r o c k s on t h e C r y L a k e and S p a t s i z i m a p - s h e e t s , N o r t h - C e n t r a l B.C. U n p u b l i s h e d B.Sc. t h e s i s , D e p a r t m e n t o f G e o l o g i c a l S c i e n c e s , U n i v e r -s i t y o f B r i t i s h C o l u m b i a . F i s h e r , R.V. 1961. P r o p o s e d c l a s s i f i c a t i o n o f v o l c a n o -c l a s t i c s e d i m e n t s and r o c k s . G e o l o g i c a l S o c i e t y o f /America, B u l l e t i n , V.72, pp. 1409-1414 . F i s h e r , R.V. 1968. Rocks composed o f v o l c a n i c f r a g m e n t s and t h e i r c l a s s i f i c a t i o n . E a r t h - S c i e n c e R e v i e w s , V . l , pp. 287-298. F l o y d , P.A., and W i n c h e s t e r , J.A. 1978. I d e n t i f i c a t i o n and d i s c r i m i n a t i o n o f a l t e r e d and metamorphosed v o l c a n i c r o c k s u s i n g i m m o b i l e e l e m e n t s . C h e m i c a l G e o l o g y , V.21, pp.291-306. G a b r i e l s e , H., Dodds, C . J . , and Mansy, J . L . 1976. Toodoggone R i v e r (94E) map-area. G e o l o g i c a l S u r v e y o f C a n a d a , Open F i l e 306. G a b r i e l s e , H., W a n l e s s , R.K., A r m s t r o n g , R.L., and Erdman, L.R. 19 80. I s o t o p i c d a t i n g o f E a r l y J a r a s s i c V o l c a n i s m and p l u t o n i s m i n n o r t h - c e n t r a l B r i t i s h C o l u m b i a . Iri C u r r e n t R e s e a r c h , P a r t A, G e o l o g i c a l S u r v e y o f C anada, P a p e r 80-1A, pp.27-32. G a r c i a , M.D. 1978. C r i t e r i a f o r t h e i d e n t i f i c a t i o n o f a n c i e n t v o l c a n i c a r c s . E a r t h - S c i e n c e R e v i e w s , V.14, pp.147-165. G i l e s , D.L., and N e l s o n , G.E. 1983. P r i n c i p a l f e a t u r e s o f e p i t h e r m a l l o d e g o l d d e p o s i t s o f t h e C i r c u m - P a c i f i c r i m . I n C o l l e c t i o n o f U n p u b l i s h e d P a p e r s on E p i t h e r m a l S i l v e r -G o l d D e p o s i t s by P a u l Eimon and O t h e r s . G e o l o g i c a l A s s o c i a t i o n o f Canada. 16p. Gunn, B.M. 1974. S y s t e m a t i c p e t r o c h e m i c a l d i f f e r e n c e s i n a n d e s i t e s u i t e s . B u l l e t i n V o l c a n o l o g i q u e , V.38, pp.481— 492. H aas, J . L . 1971. The e f f e c t s o f s a l i n i t y on t h e maximum t h e r m a l g r a d i e n t o f a h y d r o t h e r m a l s y s t e m a t h y d r o s t a t i c p r e s s u r e s . E c o n o m i c G e o l o g y , V.66, pp.940-946. H e a l d - W e t l a u f e r , P., Hayba, D.O., F o l e y , N.K., and G o s s , J.A. 1983. C o m p a r a t i v e anatomy o f e p i t h e r m a l p r e c i o u s and b a s e - m e t a l d i s t r i c t s h o s t e d by v o l c a n i c r o c k s . U n i t e d S t a t e s G e o l o g i c a l S u r v e y , O p e n - F i l e R e p o r t , no. 83-710, 16p. 162 H e l g e s o n , H.C., and G a r r e l s , R.M. 1968. H y d r o t h e r m a l t r a n s -p o r t and d e p o s i t i o n o f g o l d . E c o n o m i c G e o l o g y , V.63, pp.622-635. Hemley, J . J . , and J o n e s , W.R. 1964. C h e m i c a l a s p e c t s o f h y d r o t h e r m a l a l t e r a t i o n w i t h e m p h a s i s on h y d r o g e n meta-s o m a t i s m . E c o n o m i c G e o l o g y , V.59, pp.538-569. I r v i n e , T.N., and B a r a g a r , W.R.A. 1971. A g u i d e t o t h e c h e m i c a l c l a s s i f i c a t i o n o f t h e common v o l c a n i c r o c k s . C a n a d i a n J o u r n a l o f E a r t h S c i e n c e , V.8, pp.523-548. J a k e s , P., and W h i t e , A.J.R. 1972. M a j o r and t r a c e e l e m e n t a b u ndances i n v o l c a n i c r o c k s o f o r o g e n i c a r e a s . Geo-l o g i c a l S o c i e t y o f A m e r i c a , B u l l e t i n , V.83, pp.29-40. K a l y u z h n y i , V.A., D a v i d e n k o , N.M., Z i n c h u k , I.N., S v o r e n , I.M., and P i s o y s k i y , B . I . 19.75. R o l e o f CO2-H2O and CH4-H2O i n f o r m i n g o r e s o f g o l d a t C h u k o t k a , ( a b s t . ) . I n F l u i d I n c l u s i o n R e s e a r c h , V.8, CE. Ro e d d e r , e d i t o r ) , 82p. L a m b e r t , M.B. 1974. The B e n n e t t l a k e c a u l d r o n s u b s i d e n c e complex, B r i t i s h C o l u m b i a and Yukon T e r r i t o r y . Geo-l o g i c a l S u r v e y o f Canada, B u l l e t i n 227, 213p. L e w i s , A., ( e d . ) . 1982. G o l d g e o c h e m i s t r y : new i d e a s a b o u t t h e p a r a g e n e s i s o f h y d r o t h e r m a l d e p o s i t s have i m p l i c a t i o n s f o r f i n d i n g u n d i s c o v e r e d g o l d o r e . E a r t h and M i n i n g J o u r n a l , December, 1982, pp.56-60. Li p m a n , P.W., C h r i s t i a n s e n , R.L., and O'Connor, J . T . 1966. A c o m p o s i t i o n a l l y z oned a s h - f l o w s h e e t i n S o u t h e r n Nevada. U n i t e d S t a t e s G e o l o g i c a l S u r v e y , P r o f e s s i o n a l P a p e r , no. 524-F, 47p. L i t t l e , H.W. 1960. N e l s o n map-area, w e s t h a l f , B r i t i s h C o l u m b i a (.82 FW1/2) . G e o l o g i c a l S u r v e y o f Canada, Memoir, no. 30 8, pp.62-6 7. L o r d , C.S. 1948. M c C o n n e l l c r e e k map-area, C a s s i a r d i s t r i c t , B r i t i s h C o l u m b i a . G e o l o g i c a l S u r v e y o f Canada, Memoir 251, 72p. Monger, J.W.H. 1977. The T r i a s s i c T a k l a Group i n M c C o n n e l l c r e e k map-area, n o r t h - c e n t r a l B r i t i s h C o l u m b i a . Geo-l o g i c a l S u r v e y o f Canada, P a p e r 76—29. M u l l e r , J . E . 1971. C h e m i s t r y and p e t r o l o g y o f some M e s o z o i c V o l c a n i c r o c k s on V a n c o u v e r I s l a n d . G e o l o g i c a l S u r v e y o f C anada, P a p e r 71-T p t . B , pp.5-10. 163 M u l l e r , J . E . , N o r t h c o t e , K.E., and C a r l i s l e , D. 1974. G e o l o g y and m i n e r a l d e p o s i t s o f A l e r t Bay-Cape S c o t t m a p - a rea, V a n c o u v e r I s l a n d , B r i t i s h C o l u m b i a . Geo-l o g i c a l S u r v e y o f Canada, P a p e r no. 74-8. N a s h , J . T . 197 2. F l u i d - i n c l u s i o n s t u d i e s o f some g o l d d e p o s i t s i n Nevada. U n i t e d S t a t e s G e o l o g i c a l S u r v e y , P r o f e s s i o n a l P a p e r , no. 800-C, p p . C l 5 - C l 9 . P a n t e l e y e v , A. 1982. Toodoggone v o l c a n i c s s o u t h o f F i n l a y r i v e r . I n G e o l o g i c a l F i e l d w o r k 1981, B.C. M i n i s t r y o f E n e r g y , M i n e s and P e t r o l e u m R e s o u r c e s , P a p e r 19 8 2-1, pp.135-141. P a n t e l e y e v , A. 1983. G e o l o g y between Toodoggone and S t u r d e e r i v e r . I n G e o l o g i c a l F i e l d w o r k 1982, B.C. M i n i s t r y o f E n e r g y , M i n e s and P e t r o l e u m R e s o u r c e s , P a p e r 1983-1, pp.143-148. P a r k , C.F., and M a c D i a r m i d , R.A. 1975. Ore d e p o s i t s . W.H. Freeman and Company, New Y o r k , 53Op. P a r s o n s , W.H. 1966. C r i t e r i a f o r t h e r e c o g n i t i o n o f v o l c a n i c b r e c c i a s : r e v i e w . The G e o l o g i c a l S o c i e t y o f A m e r i c a , Memoir 115, pp.263-304. P e a r c e , T.H., Gorman, B.E., and B i r k e t t , T.C. 1977. The r e l a t i o n s h i p between m a j o r e l e m e n t c h e m i s t r y and t e c t o n i c e n v i r o n m e n t o f b a s i c and i n t e r m e d i a t e v o l c a n i c r o c k s . E a r t h and P l a n e t a r y S c i e n c e L e t t e r s , V.36, pp.121-132. P e t e r , J.M. 1983. M i n e r a l o g y , w a l l r o c k a l t e r a t i o n , and g e o c h e m i s t r y o f t h e B a k e r Au-Ag m i n e , Toodoggone R i v e r a r e a , n o r t h - c e n t r a l , B r i t i s h C o l u m b i a . U n p u b l i s h e d B.Sc. t h e s i s , D e p a r t m e n t o f G e o l o g i c a l S c i e n c e s , U n i v e r s i t y o f B r i t i s h C o l u m b i a , 9 8p. P o t t e r , R.W., I I . 1977. P r e s s u r e c o r r e c t i o n s f o r f l u i d -i n c l u s i o n h o m o g e n i z a t i o n t e m p e r a t u r e s b a s e d on t h e v o l u m e t r i c p r o p e r t i e s o f t h e s y s t e m NaCl-H20. I n J o u r n a l o f R e s e a r c h , U n i t e d S t a t e s G e o l o g i c a l S u r v e y , V.5, pp.603-607. P o t t e r , R.W., I I , C l y n n e , M.A., and Brown, D.L. 1978. F r e e z i n g p o i n t d e p r e s s i o n o f aqueous s o d i u m c h l o r i d e s o l u t i o n s . E c o n o m i c G e o l o g y , V.53, pp.235-269. P r e t o , V.A. 1974. G e o l o g y o f N i c o l a v o l c a n i c s and r e l a t e d m i n e r a l i z a t i o n a t A s p e n G r o v e , B r i t i s h C o l u m b i a . I n C o r d i l l e r a n S e c t i o n Symposium on V o l c a n i c G e o l o g y and M i n e r a l D e p o s i t s i n t h e C a n a d i a n C o r d i l l e r a , G e o l o g i c a l A s s o c i a t i o n o f Canada, P r o g r a m and A b s t r a c t s , pp.18-19. 1 6 4 Ratte, J . C , and Steven, T.A. 1967. Ashflows and related volcanic rocks associated with, the Creede Cauldera, San Juan Mountains, Colorado. United States Geological Survey, Professional Paper, no. 524-H, 58p. Ray, G.E. 1983. The Harrison Lake Fracture system of southern B r i t i s h Columbia: an exploration target for both high temperature and epithermal gold d e p o s i t s C a b s t r . ) . In The Canadian Mining and M e t a l l u r g i c a l , B u l l e t i n , V.76, 52p. Richards, T.A. 1974a. Hazelton east half (93M east h a l f ) . In Report of A c t i v i t i e s , Geological Survey of Canada Paper 76-1A, pt. A. Roedder, E. 1963. Studies of f l u i d inclusions I I : freezing data and t h e i r interpretation. Economic Geology, V.58, pp.167-211. Roedder, E. 1976. F l u i d - i n c l u s i o n evidence on the genesis of ores i n sedimentary and volcanic rocks. Iri Handbook of strat-bound and stratiform ore deposits, Wolf, K.H., ed. E l s e v i e r S c i e n t i f i c Publishing Company, Amsterdam, 363p. Roedder, E. 1977. F l u i d inclusions as tools i n mineral exploration. Economic Geology, V.72, pp.503-525. Roedder, E., and Bodnar, R.J. 1980. Geologic pressure determinations from f l u i d i n c l u s i o n studies. Annual Reviews i n Earth and Planetary Science, V.8, pp.263-301. Roedder, E. 1981. Origin of f l u i d inclusions and changes that occur af t e r trapping. In Short Course In F l u i d Inclusions: Applications to Petrology, Mineralogical Association of Canada, Chapter 5, V.6, pp.101-137. Ross, C.S,, and Smith, R.L. 1961. Ashflow t u f f s : t h e i r o r i g i n , geologic relations and i d e n t i f i c a t i o n . United States Geological Survey, Professional Paper, no. 3 66, 80p. Rozhkov, I.S. 1975. Near surface gold deposits. Geologiya Rudnykh Mestorozidenii, V.13, no.3, pp.3-14. Sawkins, F.J., O'Neil, J.R., and Thompson, J.M. 1979. F l u i d i n c l u s i o n and geochemical studies of vein gold deposits, Banguio d i s t r i c t , P h i l l i p i n e s . Economic Geology, V.74, pp.1420-1434. Schmid, R. 1981. Descriptive nomenclature and c l a s s i f i c a t i o n of p y r o c l a s t i c deposits and fragments: recommendations of the IUGS subcommission on the systematics of igneos rocks. Geology, V.9, pp.41-43. 165 S c h o e n , R., W h i t e , D.E., and Hemley, J . J . 1974. C l a y and C l a y M i n e r a l s , V.22, pp.1-22. S c h r o e t e r , T.G. 1981. Toodoggone R i v e r (94E) . I n G e o l o g i c a l F i e l d w o r k 1980, B.C. M i n i s t r y o f E n e r g y , M i n e s and P e t r o -leum R e s o u r c e s , P a p e r 1981-1, pp.124-131. S c h r o e t e r , T.G. 19 82. Toodoggone R i v e r (9 4 E ) . In G e o l o g i c a l F i e l d w o r k 1981, B.C. M i n i s t r y o f E n e r g y , M i n e s and P e t r o -leum R e s o u r c e s , P a p e r 1982-1, pp.122-134. S c h r o e t e r , T.G. 1983. Program, 8 t h a n n u a l CIM d i s t r i c t 6 m e e t i n g . The C a n a d i a n I n s t i t u t e o f M i n i n g and M e t a l l u r g y , B u l l e t i n , V.76, pp.39-53. S c h r o e t e r , T.G. 1983. Toodoggone R i v e r ( 9 4 E ) . I n G e o l o g i c a l F i e l d w o r k 1982, B.C. M i n i s t r y o f E n e r g y , M i n e s and P e t r o -leum R e s o u r c e s , P a p e r 1983-1, pp.125-133. S c h w a r t z , G.M. 1959. H y d r o t h e r m a l a l t e r a t i o n . E c o n o m i c G e o l o g y , V.54, pp.161-183. S c o t t , R.B. 1971. A l k a l i e x c h a n g e d u r i n g d e v i t r i f i c a t i o n and h y d r a t i o n o f g l a s s e s i n i g n i m b r i t e c o o l i n g u n i t s . J o u r n a l o f G e o l o g y , V.79, pp.100-110. S c o t t , R.B. 1971. C h e m i c a l v a r i a t i o n s i n g l a s s s h a r d s and i n t e r s t i t i a l d u s t o f I g n i m b r i t e c o o l i n g u n i t s . A m e r i c a n J o u r n a l o f S c i e n c e , V.270, pp.166-173. Seward, T.M. 1973. T h i o c o m p l e x e s o f g o l d and t h e t r a n s p o r t o f g o l d i n h y d r o t h e r m a l o r e s o l u t i o n s . E c o n o m i c G e o l o g y , V.37, pp.379-399. S m i t h , R.L. 1960a. A s h f l o w s . G e o l o g i c a l S o c i e t y o f A m e r i c a , B u l l e t i n , V.71, pp.795-842. S m i t h , R.L. 1979. A s h f l o w m a g n a t i s m . G e o l o g i c a l S o c i e t y o f A m e r i c a , S p e c i a l P a p e r 180, 211p. S o u t h e r , J.G. 1977. V o l c a n i s m and t e c t o n i c e n v i r o n m e n t s i n t h e C a n a d i a n c o r d i l l e r a - a s e c o n d l o o k . I n V o l c a n i c Regimes i n Canada, B a r a g a r , W.R.A., Coleman, L.C., and H a l l , J.M., e d s . , G e o l o g i c a l A s s o c i a t i o n o f Canada, S p e c i a l P a p e r , no. 16, pp.3-24. S o u t h e r l a n d Brown, A. 19 68. G e o l o g y o f t h e Queen C h a r l o t t e I s l a n d s , B r i t i s h C o l u m b i a D e p a r t m e n t o f M i n e s and P e t r o l e u m R e s o u r c e s , B u l l e t i n , no. 54, pp.153-165. S p a r k s , S.R.J., and S i g u r d s s o n , H. 1977. Magma m i x i n g : a mechanism f o r t r i g g e r i n g a c i d e x p l o s i v e e r u p t i o n s . N a t u r e , V.267, pp.315-318. S p i t z , G., and D a r l i n g , R. 1974. The p e t r o c h e m i s t r y o f a l t e r e d v o l c a n i c r o c k s s u r r o u n d i n g t h e louvem c o p p e r d e p o s i t V a l d'Or, Quebec. C a n a d i a n J o u r n a l o f E a r t h S c i e n c e , V.12, pp.1820-1849. S t e i n e r , A. 1953. H y d r o t h e r m a l r o c k a l t e r a t i o n a t W a i r a k e i , New Z e a l a n d . E c o n o m i c G e o l o g y , B u l l e t i n , V.48, pp.1-13. S t e v e n , T.A., and R a t t e , J . C . 1959. C a u l d e r a S u b s i d e n c e i n t h e C r e e d e a r e a , San J u a n M o u n t a i n s , C o l o r a d o l a b s ] , G e o l o g i c a l S o c i e t y o f A m e r i c a , B u l l e t i n , V.70, p a r t 2, pp.1788-1789. S t e v e n , T.A., and E a t o n , G.P. 1975. E n v i r o n m e n t o f o r e d e p o s i t i o n i n t h e C r e e d e M o u n t a i n s , C o l o r a d o : I . g e o l o g i c , h y d r o l o g i c and g e o p h y s i c a l s e t t i n g . E c o n o m i c G e o l o g y , V.70, pp.1023-1037. S t e v e n , T.A., and L i p m a n , P.W. 1976. C a l d e r a s o f t h e San J u a n V o l c a n i c f i e l d , s o u t h w e s t e r n C o l o r a d o . U n i t e d S t a t e s G e o l o g i c a l S u r v e y , P r o f e s s i o n a l P a p e r no. 958, 35p. T a y l o r , S.R. 1969. T r a c e e l e m e n t c h e m i s t r y o f a n d e s i t e s and a s s o c i a t e d c a l c - a l k a l i n e r o c k s . J_n P r o c e e d i n g s o f t h e A n d e s i t e C o n f e r e n c e , M c B i r n e y , A.R., e d . , S t a t e o f O r e g o n D e p a r t m e n t o f G e o l o g y and M i n e r a l I n d u s t r i e s , B u l l e t i n 6 5 193p. T i p p e r , H.W., and R i c h a r d s , T.A. 1976. J u r a s s i c s t r a t i g r a p h y and h i s t o r y o f n o r t h - c e n t r a l B r i t i s h C o l u m b i a . Geo-l o g i c a l S u r v e y o f Canada B u l l e t i n , 270, 73p. T o b i , A., and K r o l l , H. 1975. O p t i c a l d e t e r m i n a t i o n o f t h e a n - c o n t e n t o f p l a g i o c l a s e t w i n n e d by c a r l s b a d - l a w : a r e v i s e d c h a r t . A m e r i c a n J o u r n a l o f S c i e n c e , V.275, pp. 731-736. U h e r , L. 1982. G e o l o g y and g e n e s i s o f t h e M e t s a n t a n g o l d q u a r t z v e i n p r o s p e c t , n o r t h - c e n t r a l B r i t i s h C o l u m b i a . U n p u b l i s h e d B.Sc. t h e s i s , D e p a r t m e n t o f G e o l o g i c a l S c i e n c e s , U n i v e r s i t y o f B r i t i s h C o l u m b i a . Watson, P.H.W. 1981. G e n e s i s and z o n i n g o f s i l v e r - g o l d v e i n s i n t h e B e a v e r d e l l a r e a , s o u t h - c e n t r a l B r i t i s h C o l u m b i a . U n p u b l i s h e d M.Sc. t h e s i s , D e p a r t m e n t o f G e o l o g i c a l S c i e n c e s , U n i v e r s i t y o f B r i t i s h C o l u m b i a , 156p. Wedepohl, K.H. ( e d . ) . 1974. Handbook o f G e o c h e m i s t r y . S p r i n g - V e r l a g , New Y o r k , V . I I / 3 , p . 3 8 A - l . W e i s s b e r g , B.G. 1969. G o l d - s i l v e r o r e g r a d e p r e c i p i t a t e s f r o m New Z e a l a n d t h e r m a l w a t e r s . E c o n o m i c G e o l o g y , V.64, pp.95-108. W h i t e , D.E. 1981. A c t i v e g e o t h e r m a l s y s t e m s and h y d r o t h e r m a l o r e d e p o s i t s . E c o n o m i c G e o l o g y , 75th. A n n i v e r s a r y Volume, pp.392-423. W h i t e b r e a d , D.H. 1976. A l t e r a t i o n and g e o c h e m i s t r y o f T e r t i a r y v o l c a n i c r o c k s i n p a r t s o f t h e V i r g i n i a C i t y q u a d r a n g l e , Nevada. U n i t e d S t a t e s G e o l o g i c a l S u r v e y , P r o f e s s i o n a l P a p e r , no. 936, 43p. W i n c h e s t e r , J.A., and F l o y d , P.A. 1976. G e o c h e m i c a l magma t y p e d i s c r i m i n a t i o n : a p p l i c a t i o n t o a l t e r e d and meta-morphosed b a s i c i g n e o u s r o c k s . E a r t h and P l a n e t a r y S c i e n c e L e t t e r s , V.28, pp.459-469. W r i g h t , J.V., S m i t h , A . L . , and S e l f , S. 1980. A w o r k i n g t e r m i n o l o g y o f p y r o c l a s t i c d e p o s i t s . J o u r n a l o f V o l c a n o l o g y and G e o t h e r m a l R e s e a r c h , V.8, pp.315-336. APPENDIX A WHOLE ROCK ANALYSES 169 APPENDIX A: WHOLE-ROCK /ANALYTICAL DATA W h o l e - r o c k a n a l y s e s were d e t e r m i n e d u s i n g a P h i l i p s PW 1410 X - r a y F l u o r e s c e n c e S p e c t r o m e t e r . The t r a c e e l e m e n t s N i , C r , V, S r , Rb, Ba, Z r , Nb, Th, Cu, Au, Ag were d e t e r m i n e d by M i n - E n L a b s o f N o r t h V a n c o u v e r , B.C. G o l d and s i l v e r v a l u e s were d e t e r m i n e d u s i n g S p e c t r o g r a p h i c t e c h n i q u e s , whereas t h e o t h e r 10 t r a c e e l e m e n t d e t e r m i n a t i o n s were p e r f o r m e d on an I n d u c t i v e l y C o u p l e d P l a s m a (ICP) u n i t . T e c h n i q u e s f o r m a j o r and t r a c e e l e m e n t a n a l y s e s a r e o u t l i n e d i n A p p e n d i x C - l and C-2 r e s p e c t i v e l y . F e r r o u s i r o n c o n c e n t r a t i o n s were d e t e r m i n e d u s i n g a r e d o x t i t r a t i o n as d i s c u s s e d i n A p p e n d i x C-3. T o t a l w a t e r and c a r b o n d i o x i d e c o n t e n t s were d e t e r m i n e d u s i n g t h e p r o c e d u r e o f Berman (1979) w h i c h i s o u t l i n e d i n A p p e n d i x C-4 A t o t a l o f f o r t y - t h r e e m a j o r e l e m e n t a n a l y s e s a r e r e p o r t e d . Ten a r e o f H a z e l t o n v o l c a n i c s , t h i r t y - t w o a r e o f Toodoggone v o l c a n i c r o c k s , and one i s a r e p r e s e n t a t i v e sample o f t h e Omineca i n t r u s i v e s . The m a j o r e l e m e n t s a r e r e p o r t e d i n weight, p e r c e n t . The t r a c e e l e m e n t s a r e r e p o r t e d i n p a r t s p e r m i l l i o n (ppm) w i t h t h e e x c e p t i o n o f g o l d w h i c h i s i n p a r t s p e r b i l l i o n ( p p b ) . N o r m a t i v e c o m p o s i t i o n s were c a l c u l a t e d on a v o l a t i l e -f r e e b a s i s , and t h e n o r m a t i v e m i n e r a l s have t h e a b b r e v i a t i o n s l i s t e d b e l o w . 170 N o r m a t i v e C o m p o s i t i o n / A b b r e v i a t i o n s Q - Q u a r t z OR - O r t h o c l a s e AB - A l b i t e AN - A n o r t h i t e D l - D i o p s i d e EN - E n s t a t i t e FS - F e r r o s i l i t e MT - M a g n e t i t e I L - I l m e n i t e AP - A p a t i t e C - Corundum CC - C a l c i t e D.I . - D i f f e r e n t i a t i o n I n d e x 171 TABLE A-1  WHOLE-ROCK ANALYSES HAZELTON VOLCANICS Pyroxene Horblende Andesite Hornblende Andesite B i o t i t e Dyke Andesite 1021 1033 1046 1044 1040 SI02 46.49 60.40 59.77 57.74 59.95 TI02 0.89 0.51 0.62 0.84 0.49 AL203 16.98 16.19 16.72 14.98 16.64 FE203 5.84 4.31 3.31 6.27 4.09 FEO 4.29 0.51 1.66 1.88 1.98 MNO 0.15 0.18 0.16 0.13 0.18 MGO 7.07 4.26 2.19 3.12 4.09 CAO 7.39 3.43 5.66 5.81 4.07 NA20 2.92 4.27 3.15 5.04 4.10 K20 3.16 3.78 4.01 2.62 3.19 P205 0.02 0.17 0.25 0.21 0.16 C02 3.61 0.50 0.70 0.29 0.14 H20 1.37 1.09 1.99 0.99 0.91 SUM 100.18 99.60 100.19 99.62 99.99 TRACE ELEMENT CHEMISTRY NI 4 15 2 CR 37 45 84 V 127 123 127 SR 287 173 222 RB 40 300 91 BA 1140 2470 1600 ZR 100 60 75 NB 36 0 8 TH 21 28 11 CU 2 6 11 AU 5 5 10 AG 0.8 0.7 l.( NORMATIVE COMPOSITION Q 6.30 6.79 11.29 1.61 6.48 OR 18.99 22.77 24.19 15.76 19.14 AB 25.18 36.69 27.27 43.40 35.22 AN 12.94 12.97 20.03 10.70 17.72 DI 6.20 0.0 2.04 12.81 0.67 EN 7.22 10.81 5.09 5.05 10.15 FS 5.21 6.01 5.64 6.23 7.74 MT 3.10 0.97 1.03 1.66 1.24 IL 1.72 0.99 1.20 1.62 0.94 AP 0.05 0.40 0.59 0.50 0.38 C 3.78 0.45 0.0 0.0 0.0 CC 8.35 1.16 1.63 0.67 0.32 D.I. 44.78 88.41 63.62 62.84 61.92 172 TABLE A - l WHOLE-ROCK ANALYSES HAZELTON VOLCANICS S i l i c i f i e d Andesite Pyroxene Andesite Rhyolite 1061 1030 1043 1056 1022 SI02 81.91 60.49 63.99 63.18 76.21 TI02 0.41 0.52 0.45 0.45 0.15 AL203 6.01 15.91 14.94 14.80 13.90 FE203 2.29 2.83 2.78 3.17 0.57 FEO 0.02 2.29 1.63 1.20 0.24 MNO 0.10 0.18 0.16 0.16 0.16 MGO 2.16 3.65 2.30 2.40 0.32 CAO 0.49 3.32 2.71 2.69 1.30 NA20 0.31 5.22 2.07 2.25 2.88 K20 3.61 3.81 5.81 5.78 3.90 P205 0.12 0.16 0.12 0.13 0.40 C02 2.81 0.0 3.15 1.29 1.90 H20 0.20 1.15 1.63 2.20 1.20 SUM 100.44 99.53 98.53 99.70 101.41 TRACE ELEMENT CHEMISTRY NI 5 7 6 15 4 CR 0 25 35 45 17 V 21 124 85 123 154 SR 0 294 130 391 323 RB 241 47 75 56 48 BA 2460 879 1040 1080 1450 ZR 0 100 55 59 82 NB 10 1 19 0 0 TH 5 20 14 28 20 CU 16 12 11 41 5 AU . 570 10 5 5 5 AG 69.0 0.8 1.4 1.3 l . : NORMATIVE COMPOSITION Q 2.07 21.92 20.67 41.17 OR 22.94 35.07 35.12 23.09 AB 44.79 17.80 19.52 24.67 AN 9.01 5.50 4.40 5.25 Dl 5.49 0.0 0.0 0.0 EN 7.70 5.85 6.15 0.80 FS 5.54 5.70 5.61 1.15 MT 1.07 0.92 0.90 0.16 IL 1.01 0.89 0.90 0.29 AP 0.38 0.28 0.31 0.09 C 0.0 3.35 3.38 2.99 CC 0.0 2.67 3.04 0.34 D.I. 69.81 74.82 75.32 88.93 TABLE A - l WHOLE-ROCK ANALYSES OMENICA INTRUSIVE Quartz Monzonite 1066 SI02 TI02 AL203 FE203 FEO MNO MGO CAO NA20 K20 P205 C02 H20 SUM 60.87 0.55 15.58 5.63 0.80 0.18 4.65 2.66 3.89 3.92 0.21 0.09 0.79 99.82 TRACE ELEMENT CHEMISTRY NI 2 CR 23 V 138 SR 228 RB 77 BA 2350 ZR 65 NB 0 TH 13 CU 6 AU 5 AG 1.0 NORMATIVE COMPOSITION Q OR AJB AN Dl EN FS MT IL AP C CC C.I. 7.95 23.51 33.35 11.47 0.0 11.76 8.09 ,29 06 0.0 0.82 0.21 65.69 174 TABLE A-1 WHOLE-ROCK ANALYSES TOODOGGONE VOLCANICS Hornblende Andesite 1067 1091C 1095 1100 1110 SI02 61.39 57.37 56.00 59.69 59.42 TI02 0.44 0.56 0.69 0.55 0.58 AL203 16.79 15.86 16.84 15.29 15.96 FE203 2.83 4.52 6.21 5.50 5.24 FEO 2.23 1.12 0.05 0.52 1.46 MNO 0.18 0.18 0.15 0.18 0.16 MGO 3.99 4.90 2.93 2.55 4.29 CAO 2.86 1.35 6.61 4.44 4.12 NA20 4.51 1.20 3.29 1.46 2.14 K20 3.65 3.28 1.79 4.59 3.19 P205 0.19 0.18 0.35 0.21 0.17 C02 0.05 2.30 1.66 2.00 0.97 H20 0.39 6.82 2.94 2.99 2.00 SUM 99.51 99.64 99.51 99.99 99.74 TRACE ELEMENT CHEMISTRY NI 6 7 0 10 5 CR 3 0 0 3 0 V 136 137 137 166 166 SR 641 159 465 151 692 RB 23 126 63 250 69 BA 1140 1710 1750 1540 1550 ZR 69 75 155 55 59 NB 16 1 10 8 1 TH 29 26 3 27 30 CU 7 23 13 19 20 AU 5 10 5 5 15 AG 1.0 1.5 1.1 1.2 1. NORMATIVE COMPOSITION Q 6.96 13.68 11.29 23.83 19.36 OR 21.81 39.42 12.69 28.11 19.44 AB 38.40 10.72 31.10 12.80 18.65 AN 12.82 5.86 27.29 8.30 13.50 DI 0.0 0.0 3.69 0.0 0.0 EN 10.07 12.96 7.43 6.61 10.98 FS 6.66 8.96 2.79 7.66 8.58 MT 1.05 1.42 3.41 1.23 1.37 IL 0.85 1.13 1.29 1.08 1.13 AP 0.45 0.44 0.61 0.50 0.41 C 0.82 5.40 0.05 5.17 4.28 CC 0.12 0.0 1.83 4.71 2.29 D.I. 68.04 63.84 65.33 64.49 57.45 175 TABLE A - l  WHOLE-ROCK ANALYSES TOODOGGONE VOLCANICS B i o t i t e Pyroxene Hornblende Hornblende Andesite Hornblende Andesite Andesite Andesite Dyke 1140 1155 1073 1142 1070 SI02 60.86 64.71 60.69 60.25 57.71 TI02 0.39 0.46 0.51 0.56 0.84 AL203 15.59 15.77 15.91 16.25 16.91 FE203 1.56 3.49 4.29 2.49 4.35 FEO 3.19 1.39 1.21 3.21 2.63 MNO 0.16 0.18 0.14 0.17 0.15 MGO 3.04 2.45 5.47 3.89 3.16 CAO 3.88 4.44 3.25 4.93 5.95 NA20 3.52 3.63 3.29 4.87 2.95 K20 3.31 3.13 3.44 2.10 1.73 P205 0.15 0.20 0.16 0.22 0.26 C02 0.99 0.0 0.09 0.13 0.64 H20 3.00 0.0 1.85 0.72 2.43 SUM 99.68 99.88 100.29 99.86 100.69 TRACE ELEMENT CHEMISTRY NI 10 16 11 CR 19 0 ;0 V 159 121 76 SR 439 192 444 RB 54 45 36 BA 1520 998 1140 ZR 50 66 48 NB 1 7 9 TH 33 2 30 CU 6 11 f 24 AU 10 5 15 AG 0.8 1.0 1.2 NORMATIVE COMPOSITION Q 15.73 16.94 11.02 6.53 15.07 OR 20.25 18.57 20.72 12.54 10.69 AB 30.74 30.89 28.47 41.54 26.85 AN 12.36 17.57 14.79 16.51 29.90 Dl 0.0 2.68 0.0 4.80 0.23 EN 7.84 5.57 13.89 1.34 8.95 FS 6.62 5.53 6.95 6.43 3.15 MT 1.03 0.99 1.12 1.20 3.42 IL 0.77 0.90 0.99 1.08 1.26 AP 0.38 0.47 0.38 0.54 0.55 C 1.93 0.0 1.47 0.0 0.0 CC 2.35 0.0 0.21 0.32 1.56 D.I. 66.72 67.23 60.59 61.96 68.15 176 TABLE A-1 WHOLE-ROCK ANALYSES TOODOGGONE VOLCANICS Pyroxene Andesite Dyke Hornblende Andesite Bleached Andesite S i l i c i f i e d Andesite 1083 1170 1129 1086 1090 SI02 61.11 58.05 60.87 66.02 72.55 TI02 0.58 0.64 0.74 0.66 0.49 AL203 16.03 15.30 15.80 18.10 13.15 FE203 0.21 4.13 6.70 0.52 1.89 FEO 5.00 2.00 0.76 0.0 0.34 MNO 0.18 0.18 0.75 0.20 0.17 MGO 2.88 5.33 4.59 0.50 2.62 CAO 6.29 2.80 2.12 1.98 3.67 NA20 2.79 5.12 3.71 2.18 2.20 K20 1.33 3.11 2.86 6.61 1.67 P205 0.18 0.19 0.21 0.03 0.15 C02 1.45 0.97 0.05 0.60 0.50 H20 1.93 1.82 1.06 5.40 0.20 SUM 99.77 99.65 100.25 101.79 99.62 TRACE ELEMENT CHEMISTRY NI 0 2 8 CR 0 0 3 V 90 21 45 SR 345 868 45 RB 105 18 7 BA 1640 454 1670 ZR 37 60 0 NB 1 28 0 TH 16 4 12 CU 22 6 67 AU 10 10 435 AG 1.4 0.8 3.' NORMATIVE COMPOSITION Q 23.72 2.28 13.19 OR 8.07 18.86 17.20 AB 24.06 44.29 31.93 AN 21.27 6.73 9.00 DI 0.0 0.0 0.0 EN 7.31 7.82 11.59 FS 7.12 13.66 10.18 MT 1.15 1.27 1.49 IL 1.12 1.25 1.44 AP 0.43 0.45 0.49 C 2.39 1.17 3.37 CC 3.36 2.26 0.12 D.I. 55.85 66.36 63.22 177 TABLE A - l WHOLE-ROCK ANALYSES TOODOGGONE VOLCANICS S i l i c i f i e d Andesite Hornblende Dacite 1082 1161 1080 1113 1119 SI02 70.16 80.65 63.44 64.15 63.15 TI02 0.88 0.46 0.49 0.46 0.46 AL203 17.01 6.21 15.74 15.35 14.65 FE203 1.41 3.21 2.87 2.62 2.79 FEO 0.61 1.10 2.32 2.01 1.93 MNO 0.11 0.18 0.18 0.18 0.18 MGO 1.39 1.64 3.05 2.64 3.53 CAO 0.13 1.50 2.87 2.93 2.72 NA20 0.42 0.07 4.59 5.18 4.93 K20 5.84 2.95 3.56 3.39 2.91 P205 0.09 0.16 0.20 0.19 0.18 C02 2.10 1.49 0.05 0.07 1.17 H20 0.25 0.35 0.39 0.51 0.98 SUM 100.42 100.00 99.80 99.69 99.60 TRACE ELEMENT CHEMISTRY NI 2 4 7 3 CR 0 0 9 2 V 9 105 91 102 SR 513 552 488 457 RB 5 94 71 46 BA 3450 1520 1250 1250 ZR 23 52 46 55 NB 0 0 14 0 TH 1 24 25 17 CU 1 9 12 10 AU 110 5 10 15 AG 5.3 0.8 1.0 0. NORMATIVE COMPOSITION Q 10.30 9.93 13.52 OR 21.21 20.24 17.54 AB 39.16 44.15 42.23 AN 11.93 8.79 4.94 Dl 0.72 3.50 0.0 EN 7.47 5.74 8.94 FS 6.59 5.20 6.16 MT 1.07 0.96 0.98 IL 0.94 0.88 0.89 AP 0.49 0.45 0.42 C 0.0 0.16 1.66 CC 0.11 0.00 2.73 D.I. 70.67 74.33 73.28 178 TABLE A - l WHOLE-ROCK ANALYSES TOODOGGONE VOLCANICS Hornblende Hornblende Dacite Biotite--Hornblende Dacite Dacite 1164 1162 1072 1169 1135 SI02 63.13 65.97 67.15 64.12 67.94 TI02 0.61 0.32 0.38 0.61 0.58 AL203 14.99 16.99 13.49 15.35 17.02 FE203 4.40 1.31 1.65 5.80 2.50 FEO 1.63 2.70 1.08 0.22 2.10 MNO 0.21 0.18 0.18 0.17 0.17. MGO 3.60 1.85 1.57 3.59 3.65 CAO 1.54 2.50 4.01 1.55 0.43 NA20 5.97 3.35 3.62 5.96 2.51 K20 2.59 3.11 2.98 2.59 4.32 P205 0.14 0.15 0.12 0.61 0.21 C02 0.08 0.0 2.21 0.0 0.0 H20 0.50 1.57 1.11 0.60 0.80 SUM 101.41 100.03 99.56 101.21 101.29 TRACE ELEMENT CHEMISTRY NI 10 9 2 5 7 CR 4 2 0 37 2 V 95 118 83 107 59 SR 251 184 303 192 184 RB 53 39 53 ',45 39 BA 1200 1680 1130 1360 1690 ZR 55 60 61 66 60 NB 5 7 0 3 7 TH 29 35 19 25 32 CU 6 11 3 12 13 AU 10 5 5 10 5 AG 0.9 1.1 0.8 1.0 1.1 NORMATIVE COMPOSITION Q 7.91 24.74 29.14 8.73 40.35 OR 15.27 18.74 17.91 15.34 25.72 AB 50.96 28.83 31.02 51.08 4.36 AN 5.98 11.66 5.23 3.70 0.77 Dl 0.20 0.0 0.0 0.0 0.0 EN 8.87 4.68 3.98 8.95 9.18 FS 4.18 5.57 3.52 7.23 5.76 MT 1.20 0.86 0.57 1.18 0.95 IL 4.93 0.62 0.74 1.16 1.11 AP 0.32 0.35 0.28 1.41 0.49 C 0.0 3.96 2.50 1.23 11.31 CC 0.18 0.0 5.11 0.0 0.0 D.I. 75.78 72.60 77.78 76.36 70.43 179 TABLE A-1  WHOLE-ROCK ANALYSES TOODOGGONE VOLCANICS Rhyolite Trachyte 1128 1091 1130 1134 SI02 71.63 66.19 60.22 60.93 TI02 0.30 0.56 0.60 0.49 AL203 14.95 15.60 15.21 17.21 FE203 2.08 2.35 2.69 1.65 FEO 0.69 1.93 3.15 2.64 MNO 0.13 0.17 0.13 0.19 MGO 1.21 3.60 1.98 2.30 CAO 0.77 0.41 3.11 0.51 NA20 4.08 3.71 3.21 6.28 K20 4.93 4.90 8.78 7.03 P205 0.09 0.20 0.20 0.14 C02 0.0 0.0 1.00 0.02 H20 1.09 0.79 1.04 1.51 SUM 100.98 100.43 99.98 100.03 TRACE ELEMENT CHEMISTRY NI 1 8 6 CR 0 7 6 V 25 152 152 SR 262 660 47 RB 56 72 52 BA 1720 1680 1680 ZR 23 54 28 NB 5 10 10 TH 22 25 32 CU 15 13 134 AU 5 5 5 AG 0.8 0.3 O.i NORMATIVE COMPOSITION Q 29.98 17.76 0.00 0.00 OR 29.00 29.11 29.39 25.76 AB 26.43 31.71 52.86 54.68 AN 3.33 0.76 0.00 3.14 DI 0.0 0.0 2.88 2.53 EN 3.06 9.01 4.62 0.69 FS 3.54 5.31 0.73 0.0 MT 0.56 0.88 0.0 3.76 IL 0.58 1.07 0.76 1.30 AP 0.21 0.47 0.34 0.19 C 3.50 3.93 0.0 0.0 CC 0.0 0.0 0.0 0.0 D.I. 85.34 80.76 81.35 83.69 NE 5.40 5.85 OL 3.35 1.88 6 180 TABLE A-1  WHOLE-ROCK ANALYSES Pota s s i c a l l y Altered Andesites 1191 1107 SI02 59.35 60.21 TI02 0.51 0.45 AL203 15.25 16.01 FE203 2.35 1.95 FEO 3.21 3.32 MNO 0.12 0.15 MGO 1.32 1.19 CAO 3.10 2.89 NA20 3.61 3.17 K20 8.66 7.99 P205 0.19 0.18 C02 1.32 1.01 H20 1.21 2.11 SUM 100.20 100.50 TRACE ELEMENT CHEMISTRY NI 15 14 CR 15 16 V 150 140 SR 205 302 RB 45 47 BA 1817 1690 ZR 52 41 NB 15 13 TH 45 39 CU 61 40 AU 39 45 AG 2.5 2.9 NORMATIVE COMPOSITION Q OR AB AN DI EN FS MT IL AP C CC D.I. NE OL APPENDIX B FLUID INCLUSION ANALYSES 182 APPENDIX B: FLUID INCLUSION ANALYSES F l u i d I n c l u s i o n s t u d i e s were c o n d u c t e d u s i n g a C h a i x m e c a m i c r o t h e r m o m e t r y a p p a r a t u s mounted on a L e i t z O r t h o l u x I T b i n o c u l a r m i c r o s c o p e . T h i s u n i t i s d e s i g n e d f o r t h e s t u d y o f f l u i d i n c l u s i o n s i n m i n e r a l s f r o m - 1 8 0 ° C t o + 6 0 0 ° C . O p e r a t i n g p r o c e d u r e s f o r t h e s t u d y o f f l u i d i n c l u s i o n s a r e d e s c r i b e d i n A p p e n d i x D. A b b r e v i a t i o n s u s e d i n t h e f o l l o w i n g t a b l e a r e l i s t e d b e l o w . M - l - sample #1 f r o m M o o s e h o r n p r o s p e c t G-2 - sample #2 f r o m Mt. G r a v e s p r o s p e c t AM - a m e t h y s t CC - c a l c i t e PR - p r i m a r y i n c l u s i o n s SE - s e c o n d a r y i n c l u s i o n s PS - p s e u d o s e c o n d a r y i n c l u s i o n s aq - aqueous p h a s e V - v a p o u r p h a s e NVO - no v a l u e o b t a i n e d TABLE B-1 FLUID INCLUSION ANALYSES Sample Host Inclusion Dimension Phases Volumn % Last Melting Calculated Homogenization Number Mineral Type Length X Width Present (V/V+L) Temperature'C % Nacl Temperature*C (A) M-l AM PR 4.5 x 13.8 aq, V 5 -1.2 2.1 211.8 ± 7.1 M-l AM PR 12.2 x 16.5 aq, V 10 -1.6 2.8 232.0 ± 2.4 M-l AM PR 18.3 x 9.6 aq, V 20 -1.5 2.6 227.3 M-l AM SE 5.5 x 3.5 aq, V 5 -0.9 1.6 163.6 ± 4.2 M-2 AM PR 13.0 x 9.3 aq, V 5 -0.7 1.2 242.5 ± 3.4 M-2 AM SE 6.9 x 10.6 aq, V 5 -1.5 2.6 175.1 ± 2.7 M-3 AM SE 6.9 x 9.8 aq, V 20 NVO NVO 159.9 M-5 AM SE 8.0 x 13.6 aq, V 10 -3.1 5.1 184.4 ± 3.6 M-6 AM PR 10.4 x 19.2 aq, V 20 -3.4 5.5 237.9 M-9 AM SE 3.2 x 5.7 aq, V 5 -2.9 4.8 169.7 ± 2.7 M-9 AM SE 7.2 x 9.1 aq, V 5 165.4 ± 3.6 M-9 AM SE 6.5 x 10.6 aq, V 10 -1.9 1.9 185.2 ± 2.3 Sample Host I n d u s Number Mineral Type M-9 AM PR M-9 AM PR M-9 AM PR M-9 AM SE M-9 AM SE M-9 AM SE M-10 AM PR M-10 AM PR M-10 AM PR M-10 AM PS M-10 AM PR M-10 AM SE Dimension Phases Length X Width Present (.Mi 9.6 x 15.3 aq, V 8.7 x 13.6 aq, V 10.4 x 16.7 aq, V 6.9 x 11.4 aq, V 3.5 x 6.6 aq, V 7.4 x 13.6 aq, V 12.4 x 15.6 aq, V 7.3 x 13.6 aq, V 7.4 x 8.6 aq, V 10.9 x 5.4 aq, V 7.9 x 16.8 aq, V 5.6 x 9.6 aq, V Volumn % Last Melting (V/V+L) Temperature °C 5 -2.3 15 -2.5 5 -1.9 5 -0.9 10 NVO 5 -0.5 5 -0.7 5 -0.9 10 NVO 15 NVO 10 -1.1 5 -1.3 Calculated Homogenization % Nacl Temperature °C 3.9 250.3 4.1 237.4 ± 5.8 3.2 223.9 ± 3.3 1.6 161.4 ± 2.6 NVO 163.9 ± 4.8 0.8 175.1 ± 5.2 1.2 235.8 ± 2.6 1.6 236.6 ± 6.2 NVO 228.7 ± 2.6 NVO 203.4 ± 7 . 9 1.9 231.1 ± 1.6 2.3 169.3 LT) 00 H Sample Host I n c l u s i Number Mineral Type M - l l AM PR M - l l AM PR M - l l AM PR M-12 AM PR M-12 AM SE M-12 AM SE M-12 AM SE M-12 AM PR M-12 AM PR M-13 AM PR M-13 AM PR M-13 AM PR Dimension Phases Length X Width Present ( A ; 13.3 x 18.6 aq, V 10.3 x 13.4 aq, V 11.4 x 15.6 aq, V 8.7 x 12.4 aq, V 6.3 x 11.3 aq, V 8.0 x 10.6 aq, V 7.1 x 8.4 aq, V 11.4 x 13.3 aq, V 8.9 x 15.6 aq, V 6.7 x 11.9 aq, V 8.6 x 10.7 aq, V 7.1 x 13.9 aq, V Volumn % Last Melting (V/V+L) Temperature"C 15 -3.8 10 -3.2 5 -2.9 10 NVO 5 -2.6 5 -0.2 5 -0.9 10 -1.8 5 -2.1 10 -1.1 5 -2.7 15 -0.6 Calculated Homogenization % Nacl Temperature°C 6.1 245 ± 5.6 5.3 250.7 ± 8.7 4.8 234.9 ± 3.1 NVO 215.6 ± 1.7 4.3 160.4 0.4 180.9 ± 0.7 1.6 168.4 ± 0.3 3.1 243.9 ± 3.3 3.5 244.4 ± 4.6 1.9 236.7 ± 6.9 4.5 226.9 ± 3.1 228.6 + 2.7 vo CO rH Sample Host I n c l u s i Number Mineral Type M-13 AM PR M-13 AM PR M-13 AM PR M-13 AM PR M-15 AM PR M-15 AM PR M-15 AM PR M-15 AM SE M-15 AM SE M-16 AM PR M-16 AM SE M-16 AM PR Dimension Phases Length X Width Present (M) 10.1 x 14.9 aq, V 8.7 x 11.9 aq, V 9.9 x 15.7 aq, V 6.1 x 10.4 aq, V 8.1 x 11.7 aq, V 6.1 x 15.9 aq, V 7.3 x 8.4 aq, V 6.9 x 10.3 aq, V 8.7 x 12.9 aq, V 7.9 x 11.7 aq, V 4.2 x 6.9 . aq, V 8.7 x 14.6 aq, V Volumn % Last Melting (V/V+L) Temperature"C 10 -0.6 5 -0.9 5 -1.7 10 NVO 10 NVO 10 -3.9 5 -3.9 15 -2.9 5 -3.1 10 -1.9 5 10 -0.6 Calculated Homogenization % Nacl Temperature'C 1.0 231.7 ± 5.1 1.6 239.8 ± 0.9 2.9 229.4 + 4.9 NVO 232.4 ± 2.9 NVO 225.6 ± 1.3 6.3 228.1 ± 6.7 6.3 246.1 4.8 167.6 ± 4.3 5.1 183.4 3.3 220.1 ± 0.9 179.6 + 1.7 1.0 240.3 Sample Host I n d u s Number Mineral Type M-16 AM PR M-16 AM PR M-16 AM SE M-17 AM PR M-17 AM PR M-17 AM PR M-17 AM SE M-18 AM SE M-18 AM PR M-19 CC PR M-19 CC PR M-19 CC PR Dimension Phases Length X Width Present 9.3 x 13.9 aq, V 7.3 x 10.7 aq, V 6.9 x 9.5 aq, V 11.3 x 15.4 aq, V 7.9 x 15.6 aq, V 11.2 x 13.5 aq, V 6.9 x 9.6 aq, V 3.5 x 8.9 aq, V 5.9 x 15.3 aq, V 3.5 x 6.4 aq, V 4.4 x 8.3 aq, V 5.6 x 9.3 aq, V Volumn % Last Melting (V/V+L) Temperature"C 5 -1.1 15 NVO 5 -2.5 10 -3.8 5 -3.5 5 NVO 5 -0.9 5 NVO 5 -3.9 5 -0.5 8 -0.2 10 NVO Calculated Homogenization % Nacl Temperature°C 1.9 222.6 ± 3.9 NVO 226.1 ± 4.2 4.1 166.6 ± 5.1 6.1 215.1 5.7 235.6 NVO 219.1 ± 0.9 1.6 170.6 ± 2.9 NVO 159.5 ± 4.1 6.3 218.1 ± 1.9 0.8 138.7 ± 9.1 0.4 129.6 NVO 127.9 ± 6.6 Sample Host I n d u s Number Mineral Type M-19 CC PR M-19 CC PR M-19 CC PR M-20 AM PS M-20 AM PS G-l AM PR G-l AM PR G-l AM SE G-l AM PR G-l AM PR G-l AM PR G-l AM PR Dimension Phases Length X Width Present (M) 3.5 x 7.0 aq, V 7.3 x 9.6 aq, V 4.1 x 6.3 aq, V 6.7 x 9.3 aq, V 5.5 x 8.5 aq, V 6.7 x 11.3 aq, V 8.9 x 16.1 aq, V 5.5 x 9.6 aq, V 7.0 x 12.9 aq, V 8.3 x 11.3 aq, V 5.1 x 10.1 aq, V 5.9 x 11.7 aq, V Volumn % Last Melting (V/V+L) Temperature°C 10 NVO 5 -1.5 5 NVO 5 NVO 8 NVO 10 NVO 5 -4.1 5 NVO 15 -4.7 5 -4.9 5 -2.1 15 -3.6 Calculated Homogenization % Nacl Temperature°C NVO 145.9 ± 5.1 2.6 130.1 ± 3.7 NVO 116.4 ± 1.9 NVO 207.5 NVO 212.0 NVO 268.5 ± 3.9 6.5 269.0 NVO 226.4 ± 8.6 7.4 276.1 ± 3.7 7.6 266.6 ± 1.9 3.6 258.5 ± 3.9 5.8 26Q.9 ± 4.7 Sample Host I n c l u s i Number Mineral Type G-l AM PR G-2 AM PR G-2 AM SE G-2 AM SE G-2 AM PR G-2 AM SE G-2 AM PR G-3 AM PR G-3 AM SE G-3 AM SE G-3 AM SE G-4 AM PR Dimension Phases Length X Width Present (M) 6.6x9.3 aq, V 10.1 x 13.6 aq, V 6.6 x 9.3 aq, V 7.1 x 10.4 aq, V 4.6 x 11.7 aq, V 6.6 x 10.3 aq, V 10.1 x 12.4 aq, V 8.3 x 13.9 aq, V 7.9 x 10.4 aq, V 3.7 x 9.4 aq, V 6.3 x 10.9 aq, V 6.9 x 10.4 aq, V Volumn % Last Melting (V/V+L) Temperature" C 15 NVO 30 -4.5 10 -2.2 5 -2.9 5 -4.8 10 -1.9 45 -3.4 8 -3.6 10 -2.1 8 -2.3 25 -2.5 10 -4.8 Calculated Homogenization % Nacl Temperature°C NVO 269.4 ± 2.1 7.1 252.6 ± 1.7 3.7 200.5 2.9 199.3 ± 4.3 7.5 278.6 + 5.9 3.2 210.1 ± 5.5 5.6 269.1 5.8 274.3 ± 1.7 3.6 201.4 ± 3.1 3.8 225.9 ± 5.9 4.1 214.1 7.5 281.6 o ON Sample Host Inclusion Dimension Phases Number Mineral Type Length X Width Present (M) G-4 AM PR 7.3 x 12.6 aq, V G-4 AM PR 6.1 x 10.9 aq, V G-4 AM PR 10.1 x 15.7 aq, V G-4 AM SE 3.7 x 8.3 aq, V G-4 AM SE 7.2 x 9.1 aq, V G-4 AM PR 6.7x9.3 aq,V G-4 AM PR 9.7 x 12.7 aq, V G-5 AM PR 7.9 x 11.2 aq, V G-5 AM PR 9.9 x 14.3 aq, V G-5 AM SE 5.4 x 9.6 aq, V G-5 AM SE 6.7 x 10.1 aq, V G-5 AM PR 9.0x8.6 aq,V Volumn % Last Melting (V/V+L) Temperature "C 15 -5.1 5 -4.9 35 -3.6 5 NVO 25 -3.1 10 -4.1 10 -3.9 45 -4.6 10 -3.2 5 -2.6 5 -1.9 5 -3.9 Calculated Homogenization % Nacl Temperature'C 7.8 269.1 7.6 268.4 ± 0.5 5.8 255.3 ± 2.7 NVO 200.9 5.1 211.9 ± 6.1 6.5 296.1 ± 6.2 6.3 245.6 + 3.9 7.4 261.9 ± 8.3 5.3 255.7 ± 3.1 4.4 213.8 + 2.6 3.25 208.7 ± 0.6 6.3 264.6 ± 1.5 APPENDIX C GEOCHEMICAL LABORATORY TECHNIQUES 192 APPENDIX C - l : SAMPLE PREPARATION AND MAJOR ELEMENT ANALYSIS I n t h e f i e l d , t h r e e pound b u l k c h i p samples were c o l l e c t e d o f r e p r e s e n t a t i v e v o l c a n i c r o c k s . C a r e was t a k e n t o o b t a i n r e l a t i v e l y u n a l t e r e d samples f r e e o f w e a t h e r e d e x t e r i o r s and l i c h e n c o v e r i n g s . A r g i l l i c a l l y a l t e r e d and s i l i c i f i e d m a t e r i a l was a l s o o b t a i n e d f o r c o m p a r i s o n w i t h t h e i r u n a l t e r e d e q u i v a l e n t s . The c h i p s a m p l e s were p r o c e s s e d t h r o u g h a jaw c r u s h e r and d i s c m i l l , b e f o r e t h e i r f i n a l p u l v e r i z a t i o n t o l e s s t h a n minus 80-mesh i n a r i n g m i l l . A f t e r p r o c e s s i n g s a m p l e s were s p l i t and t h e s u b - s a m p l e s were p l a c e d i n p l a s t i c v i a l s . A p p r o x i m a t e -l y 10 d u p l i c a t e s a m p l e s were s p l i t and a n a l y s e d as s e p a r a t e s amples f o r q u a l i t y c o n t r o l . Once i n powdered f o r m , u n d i l u t e d p e l l e t s were p r e s s e d u s i n g 3 grams o f sample and a p p r o x i m a t e l y 1 t e a s p o o n o f B o r i c a c i d . Samples were a n a l y s e d f o r SIO^, TiO,,, A ^ O ^ F e 2 0 3 t o t a l , MnO, MgO, CaO, N a 2 0 , K^O and P 2 ° 5 a t t n e D e p a r t m e n t o f Geo-l o g i c a l S c i e n c e s , U n i v e r s i t y o f B r i t i s h C o l u m b i a u s i n g a P h i l i p s PW 1410 X - r a y F l u o r e s c e n c e S p e c t r o m e t e r . R e s u l t i n g peak and b a c k g r o u n d i n t e n s i t i e s f o r t h e m a j o r e l e m e n t s were r e c a l c u l a t e d as w e i g h t p e r c e n t o x i d e s u s i n g a m a j o r e l e m e n t d a t a r e d u c t i o n p r o g r a m as p r e s e n t e d by N i x o n ( 1 9 7 9 ) . O p e r a t i n g c o n d i t i o n s f o r t h e 10 m a j o r e l e m e n t s a r e p r e s e n t e d on t h e f o l l o w i n g 2 p a g e s . oo TABLE C - l OPERATING CONDITIONS FOR XRF MAJOR ELEMENT ANALYSIS ELEMENT Fe Line Kd 29 57.55 Target Cr C r y s t a l LLF200 KV/MA 50/35 Collimator Fine Counter Fine Vacuum ON Gain 128 Counter HV 8.03 x 2 Lower Level 150 Window 700 Count Time 10 Sec Fe bkg T i T i bkg Ca Ca bkg K K bkg S i S i bkg • 56.00 86.22 91.00 113.17 110.40 136.80 132.15 109.27 113.45 PET 50/16 50/35 50/40 -> > ELEMENT A l A l bkg P P bkg Mg Mg bkg Na Na bkg Mn Mn bkg Line Kd • 20 145.43 139.00 89.58 92.60 45.21 44.00 55.20 53.40 63.01 65.00 Target Cr • W • Crystal PET • TLAP : • L1F200 • KV/MA 50/40 ^ Collimator Coarse Fine ^ Counter Fine — ^ Vacuum ON — ^ Gain 128 ^ 64 ^ 128 ^ Counter HV 8.03 x 2 • 8.61 x 2 ^ 8.03 x 2 • Lower Level 150 • 300 • 180 • 150 • Window 700 • 360 • 220 • 700 • Count Time 10 sec. ^ 100 sec. 10 sec. 10 sec. 10 sec. 20 sec. ^ 195 APPENDIX C-2: T r a c e E l e m e n t TCP D i g e s t i o n T e c h n i q u e 1) S t r o n g A c i d D i g e s t i o n a) 1/2 gm. o f powdered sample i s d i l u t e d t o 25 m i s . w i t h a m i x t u r e o f HNO^ and H C l . b) h e a t m i x t u r e a t 250 d e g r e e s c e n t i g r a d e f o r t h r e e h o u r s . 2) F u s i o n s a) 0.2 gms. o f powdered sample i s f u s e d i n a n i c k l e c r u c i b l e w i t h NaOH f l u x . b) 0.2 gms. o f powdered sample i s f u s e d i n a n i c k l e c r u c i b l e w i t h KOH f l u x . 196 APPENDIX C-3; DETERMINATION OF FERROUS IRON ( a f t e r Berman, 1979) e q u i p m e n t : r e a g e n t s : 5- 10 T e f l o n T e s t Tubes + Caps B o r i c A c i d (10 G/sample) 1 Sand B a t h and H o t p l a t e B a r i u m D i p h e n y l a m i n e S u l f o n a t e (.01 G/10) 1 P l a s t i c C o a t e d W i r e Rack P o t a s s i u m 1 M i c r o b u r e t P l u s S t a n d D i c h r o m a t e (.6 825 G) 1 M a g n e t i c S t i r r e r P h o s p h o r i c A c i d (50 ml/10 Samples) 2-•5 M a g n e t i c S t i r r i n g Rods H y d r o f l o u r i c A c i d I n 2- 3 100 M l V o l u m e t r i c F l a s k s D i s p e n s i n g B o t t l e (2 ml/sample) 1 1 L i t r e V o l u m e t r i c F l a s k S u l f u r i c A c i d I n 1 10 M l G r a d u a t e d C y l i n d e r D i s p e n s i n g B o t t l e (2 Ml/sample) 5- 10 6 00 M l P y r e x B e a k e r s D i s t i l l e d W a t e r 2 100 M l P y r e x B e a k e r s (400 M l / s a m p l e ) 1 G l a s s S t i r r i n g Rod 1 T i m e r (10 M i n u t e s ) 1 M e t a l Tongs S u p p l y : A l l r e a g e n t s and e q u i p m e n t a r e k e p t i n Dr. K. F l e t c h e r ' s l a b (room 2 1 3 ) , w i t h t h e f o l l o w i n g e x c e p t i o n s : A t i m e r c a n be b o r r o w e d f r o m t h e d e p a r t m e n t d a r k r o o m , and m e t a l t o n g s f r o m t h e X - r a y l a b . D i s t i l l e d w a t e r , and h y d r o f l o u r i c and s u l p h u r i c a c i d i n d i s p e n s i n g b o t t l e s a r e a v a i l a b l e f r o m t h e s t r o n t i u m c h e m i s t r y l a b . B o r i c a c i d ( c r y s t a l s ) a r e a v a i l a b l e f r o m g e o l o g y s u p p l i e s . 197 Method: P r e p a r e t h e f o l l o w i n g s o l u t i o n s ( s o l u t i o n s 1 and 2 c a n be made one week e a r l y b u t s o l u t i o n 3 s h o u l d be made j u s t b e f o r e t h e r e s t o f t h e p r o c e d u r e i s d o n e ) : 1) I n d i c a t o r s o l u t i o n : d i s s o l v e 0.01 g b a r i u m d i p h e n y l a m i n e s u l f o n a t e i n 50 m l w a t e r . Add 50 m l p h o s p h o r i c a c i d and . d i l u t e t o 100 m l . I t i s n o t c r i t i c a l t h a t a l l t h e b a r i u m d i p h e n y l a m i n e i s d i s s o l v e d c o m p l e t e l y ; i t o n l y e f f e c t s t h e i n t e n s i t y o f t h e c o l o u r o f t h e f i n a l s o l u t i o n . 2) T i t r a t i o n s o l u t i o n : d i s s o l v e .6825 g p o t a s s i u m d i c h r o m a t e ( d r i e d a t 110°C f o r 2 h o u r s ) i n w a t e r and d i l u t e t o 1 l i t e r . Must be a c c u r a t e . 3) B o r i c a c i d s o l u t i o n : d i s s o l v e 10 g b o r i c a c i d i n 400 ml w a t e r ( i n 600 m l b e a k e r ) and b r i n g t o v i g o r o u s b o i l . A l l o w s o l u t i o n t o c o o l . R e p e a t f o r e a c h sample t o be a n a l y z e d . T h i s s o l u t i o n f o r m s a complex w i t h t h e f e r r o u s i o n t o p r e v e n t o x i d a t i o n t o f e r r i c i o n . Weigh a c c u r a t e l y s a m p l e s o f a p p r o x i m a t e l y 40 0 mg e a c h i n t o a s e r i e s o f t e f l o n t e s t t u b e s . R i n s e sample down s i d e s o f t e s t t u b e w i t h as l i t t l e w a t e r as p o s s i b l e . Add 2 ml s u l f u r i c a c i d t o t e s t t u b e and t h e n 2 m l h y d r o f l o u r i c a c i d c ap i m m e d i a t e l y and b r i n g t o r a p i d b o i l i n sand b a t h f o r 10 m i n u t e s . N o t e : Sample o x i d i z e s r e a d i l y o n c e HF i s added so be q u i c k w i t h p r o c e d u r e once i t i s added. I f v e r y l i t t l e w a t e r 198 was u s e d t o wash down sample i n t e s t t u b e , t h e a c i d s c a n be m i x e d w i t h a s m a l l amount o f w a t e r i n a t e f l o n t e s t and t h e n added t o s a m p l e . S i n c e t h e m i x t u r e o f t h e s e r e a g e n t s i n v o l v e s a s t r o n g l y e x o t h e r m i c r e a c t i o n , a d d i t i o n o f t h i s h o t a c i d m ix-t u r e w i l l a l l o w sample t o r e a c h a b o i l more q u i c k l y . Use t i m e r t o make s u r e b o i l i n g t i m e i s n o t more t h a n 10 m i n u t e s . R i s k o f o x i d a t i o n o f f e r r o u s i r o n i n c r e a s e s g r e a t l y w i t h p r o -l o n g e d b o i l i n g . W h i l e sample i s b o i l i n g f i l l g r a d u a t e d c y l i n d e r w i t h 10 ml i n d i c a t o r s o l u t i o n . P o u r a b o u t 100 m l o f b o r i c a c i d f r o m 60 0 m l b e a k e r i n t o 100 ml b e a k e r . U s i n g m e t a l t o n g s , remove t e s t t u b e f r o m s a n d b a t h and i m m e d i a t e p l u n g e i t (cap s i d e down) i n t o 6 00 ml b e a k e r c o n t a i n i n g 300 ml b o r i c a c i d . Use g l a s s s t i r r i n g r o d t o p u s h cap o f f t e s t t u b e . Keep t e s t t u b e immersed (sample o u t o f c o n -t a c t w i t h a i r ) w h i l e r i n s i n g g l a s s r o d and t e s t t u b e cap w i t h b o r i c a c i d f r o m s m a l l b e a k e r i n t o l a r g e one. L i f t t e s t t u b e f r o m b e a k e r and q u i c k l y f i l l s e v e r a l t i m e s w i t h b o r i c a c i d f r o m s m a l l b e a k e r e m p t y i n g c o n t e n t s e a c h t i m e i n t o l a r g e b e a k e r . Add 10 m l i n d i c a t o r s o l u t i o n t o 60 0 ml b e a k e r c o n t a i n i n g b o r i c a c i d p l u s sample and b e g i n t o s t i r on m a g n e t i c s t i r r e r . T i t r a t e w i t h p o t a s s i u m d i c h r o m a t e s o l u t i o n u n t i l p e r m a n ent p u r p l e t i n g e i s o b t a i n e d . C o l o u r w i l l o f t e n a p p e a r and t h e n d i s s a p p e a r as m i x i n g o f s o l u t i o n p r o c e e d s . N o t e ; i n t h e e n t i r e p r o c e d u r e , o n l y t h r e e measurements 199 a r e c r i t i c a l t o t h e a c c u r a t e d e t e r m i n a t i o n o f f e r r o u s i r o n : t h e p r o p o r t i o n s o f t h e t i t r a t i o n s o l u t i o n , t h e w e i g h t o f s a m p l e , and t h e volume o f t i t r a t i o n s o l u t i o n u s e d . C a l c u l a t i o n s : t h e o x i d a t i o n - r e d u c t i o n e q u a t i o n i s : Cr207 + 14 H + 6 Fe === 6 Fe + 2 C r + 7 H20 m o l e s Cr207 = (.6825/294.2)*(volume t i t . s o l n . i n l i t r e s ) m o l e s FeO = (wgt o f sample (mg)) (% F e 0 ) / 7 1 . 8 5 % FeO = 6 * .6825 * 71.85 * v o l . T i t . s i ( m l ) * 100 29 4.2 * wgt sample (mg) % FeO = 100 * v o l t i t . s i ( m l ) / w g t sample(mg) 200 APPENDIX C-4: DETERMINATION OF TOTAL WATER AND CARBON DIOXIDE ( a f t e r Berman, 1979) D e s c r i p t i o n o f A p p a r a t u s : The a p p a r a t u s and p r o c e d u r e i n v o l v e d has b e e n m o d i f i e d f r o m t h a t o f H u t c h i n s o n ( 1 9 7 4 ) . F i g u r e 36 p r e s e n t s a l a b e l l e d s k e t c h o f t h e a p p a r a t u s . I t c o n s i s t s o f an o p e n - b o r e f u r n a c e w i t h a t h r e e f o o t l o n g , 18 mm i n t e r n a l d i a m e t e r s i l i c a t u b e r u n n i n g t h r o u g h i t and i n w h i c h s a m p l e s a r e p l a c e d . I t i s a t t a c h e d a t b o t h e n d s t o d r y i n g t u b e s by means o f t y g o n t u b i n g and r u b b e r s t o p p e r s wrapped i n t e f l o n t a p e . N i t r o g e n d e l i v e r e d f r o m a s t o r a g e t a n k , i s c l e a n e d by p a s s i n g t h r o u g h t h e f i r s t two d r y i n g t u b e s , sweeps t h r o u g h t h e s i l i c a t u b e , and t h e n p a s s e s t h r o u g h t h e f i n a l d r y -i n g t u b e s i n w h i c h t h e amount o f w a t e r and c a r b o n d i o x i d e g a i n e d f r o m t h e sample i s m e a s u r e d . W ater i s a b s o r b e d i n t h e f i r s t d r y i n g t u b e (H20) w h i c h i s f i l l e d w i t h magnesium p e r c h l o r a t e . C a r b o n d i o x i d e i s a b s o r b e d i n t h e s e c o n d t u b e ( C ^ ) w h i c h c o n -t a i n s a s c a r i t e . The one-way f l o w o f n i t r o g e n ends i n a b e a k e r c o n t a i n i n g m i n e r a l o i l , i n w h i c h t h e f l o w r a t e c a n be v i s u a l l y e s t i m a t e d . S u p p l y : Magnesium p e r c h l o r a t e and a s c a r i t e c a n be o r d e r e d f r o m F i s h e r S c i e n t i f i c ; one-pound b o t t l e s o f e a c h a r e now k e p t i n t h e X - r a y l a b . The d r y i n g t u b e s need n o t be r e f i l l e d f o r s c o r e s o f s a m p l e s . A s c a r i t e c h a n g es f r o m a brown t o w h i t e c o l o r when i t i s e x h a u s t e d , and magnesium p e r c h l o r a t e s h o u l d be c h a n g e d o n l y i f b l a n k v a l u e s a p p e a r t o be e r r a t i c o r i f t h e H20 t u b e l o s e s w e i g h t on b l a n k r u n s . C o m b u s t i o n b o a t s and c r u c i b l e s a r e k e p t i n t h e X - r a y l a b . 201 The c o l l e c t i o n consists of 5 five-centimeter v i t r e o s i l boats, 5 ten-centimeter v i t r e o s i l boats, 2 ten-centimeter Coors porcelain boats, and 3 five-centimeter Coors porcelain boats. Porcelain boats should be used at temperatures above 1100 degrees Celsius. Procedure: Switch variac on, turn up to 115 v o l t s , and allow to warm up to 2 hours. Temperature should be i n the range 1050-1100 degrees Celsius, but w i l l climb slowly with time. After 4-5 hours turn the variac down to 110 v o l t s . A c a l i b r a t i o n chart of temperature versus variac voltage i s attached to the variac. Open a l l valves i n the four drying tubes, open the pressure valve on the nitrogen tank, and open the needle valve on the regulator. Slowly turn the main adjusting valve on the regul-ator u n t i l bubbles of nitrogen can be seen i n the mineral o i l bath. Flow should be continuous and just slow enough that bubbles can be counted i n d i v i d u a l l y . Determination of Blank: As the flow of nitrogen gas alone causes the water and carbon dioxide c o l l e c t i o n tubes to gain weight, a blank value should be determined before each batch of samples i s run. These correction factors should not be more than 0.3 mg and 2 mg per hour for C02 and H20, respectively. Using a l i n t free c l o t h to handle drying tubes, close valves on H20 and C02 tubes, remove tygon tubing, accurately weigh each tube, and reconnect. As pressure w i l l b u i l d up once the valves are closed, disconnect tygon tube 1 from the 202 H20 t u b e as s o o n as t h e f i r s t v a l v e i s c l o s e d . D i s c o n n e c t t u b e 2 f r o m t h e H20 t u b e , u n s c r e w clamp and w e i g h t u b e . Reclamp i n p o s i t i o n and r e c o n n e c t t u b e 2; d i s c o n n e c t t u b e 2 and t u b e 3 f r o m t h e C02 t u b e , u n s c r e w c l a m p , w e i g h , r e c l a m p , and r e c o n n e c t t u b e s 2 and 3. Open v a l v e s i n b o t h d r y i n g t u b e s and r e c o n n e c t t u b e 1. A d j u s t f l o w r a t e as a b o v e . N o t e t i m e . Run b l a n k f o r 1 h o u r . F o l l o w i n g t h e w e i g h i n g p r o c e d u r e a b o v e , o b t a i n t h e w e i g h t g a i n e d by e a c h d r y i n g t u b e , and d i v i d e by t h e t i m e o f t h e r u n t o a r r i v e a t a c o r r e c t i o n v a l u e f o r b o t h H20 and C02. D e t e r m i n a t i o n o f H20 i n s a m p l e s : A c c u r a t e l y w e i g h a p p r o x -i m a t e l y one gram o f e a c h sample i n t o C o o r s p o r c e l a i n c r u c i b l e s . D r y a t 110 d e g r e e s c e n t i g r a d e f o r one h o u r . C o o l and r e w e i g h . W e i g h t l o s s e q u a l s H20 . S t o r e s a m p l e s i n d e s s i c a t o r f o r d e t e r m i n a t i o n o f H20 and C02. D e t e r m i n a t i o n o f H20 and C02 i n s a m p l e : A c c u r a t e l y w e i g h a p p r o x i m a t e l y one gram o f sample i n t o s m a l l v i t r e o s i l c o m b u s t i o n b o a t . I f sample i s t o be r e u s e d l a t e r f o r f u r t h e r c h e m i c a l a n a l y s e s , use l a r g e r v i t r e o s i l o r C o o r s p o r c e l a i n c o m b u s t i o n b o a t s l i n e d w i t h n i c k e l f o i l i n o r d e r t o a v o i d c o n t a m i n a t i o n between s a m p l e s . N o t e t i m e . I f more t h a n 15 m i n u t e s has p a s s e d s i n c e t h e l a s t w e i g h i n g o f t h e d r y i n g t u b e s , i t i s b e s t t o r e w e i g h t o o b t a i n i n i t i a l v a l u e s . R e c o n n e c t t u b e 1 t o t h e H20 t u b e and i m m e d i a t e l y p u l l 203 s t o p p e r A f r o m t h e s i l i c a t u b e . The f l o w o f n i t r o g e n t h r o u g h t h e t u b e p r e v e n t s a i r f r o m e n t e r i n g t h e s y s t e m . P l a c e combus-t i o n b o a t w i t h sample i n t o t h e end o f t h e s i l i c a t u b e and, u s i n g t h e i r o n p u s h r o d , p u s h t h e b o a t i n t o t h e f u r n a c e u n t i l t h e r e d mark on t h e p u s h r o d i s a l i g n e d w i t h t h e end o f t h e s i l i c a t u b e . Q u i c k l y , b u t s m o o t h l y , remove t h e p u s h r o d and r e p l a c e t h e s t o p p e r a t t h e end o f t h e s i l i c a t u b e . Check t h e m i n e r a l o i l b a t h f o r t h e f l o w o f n i t r o g e n . A d j u s t t h e r a t e o f f l o w by means o f t h e r e g u l a t o r o r n e e d l e v a l v e s o t h a t b u b b l e s a r e c o n t i n u o u s b u t j u s t s l o w enough t o be i n d i v i d u a l l y c o u n t e d . T h i s g i v e s a f l o w o f a p p r o x i m a t e l y 3 l i t e r s p e r h o u r . C a r e s h o u l d be t a k e n t h a t t h e r a t e o f f l o w i s t h e same as t h a t d u r i n g t h e b l a n k d e t e r m i n a t i o n . V a p o u r w i l l c o n d e n s e on t h e i n s i d e o f t h e s i l i c a t u b e , s l o w l y p r o g r e s s down t h e t u b e , i n t o t h e p y r e x t u b e i n s e r t e d i n r u b b e r s t o p p e r A, and e v e n t u a l l y o n t o t h e arm o f t h e H20 t u b e . The r u n c a n be t e r m i n a t e d when c o n d e n s a t i o n d r o p l e t s a r e no l o n g e r v i s i b l e on t h e arm o f t h e H20 t u b e . N o t e t i m e . C l o s e v a l v e s on t h e H20 and C02 t u b e s , and remove r u b b e r s t o p p e r A. P u s h sample as f a r as p o s s i b l e with, t h e f l a t t e n e d end o f t h e p u s h r o d , hook t h e c o m b u s t i o n b o a t and draw i t o u t o f t h e s i l i c a t u b e u n t i l i t o v e r h a n g s t h e edge enough t o be g r a s p e d w i t h a p a i r o f t w e e z e r s . S e t t h e b o a t on t h e a s b e s t o s p a d t o c o o l . R e p l a c e s t o p p e r B, t h e n s t o p p e r A, and d i s c o n n e c t t u b e 1 f r o m t h e H20 t u b e . Weigh t h e two d r y i n g t u b e s a c c o r d i n g t o t h e p r o c e d u r e 204 o u t l i n e d a b o v e . L o a d n e x t sample i n t o t h e c o m b u s t i o n a p p a r a t u s t o b e g i n s e c o n d d e t e r m i n a t i o n . Weigh t h e c o m b u s t i o n b o a t p l u s sample w h i c h , by t h e n , s h o u l d be c o o l enough t o t o u c h . C a l c u l a t i o n s : O b t a i n t h e w e i g h t g a i n e d by e a c h d r y i n g t u b e by s u b t r a c t i n g , t h e i n i t i a l w e i g h t s o f t h e t u b e s f r o m t h e w e i g h t s a f t e r t h e r u n . S u b t r a c t t h e a p p r o p r i a t e c o r r e c t i o n v a l u e s ( a d j u s t e d t o t h e l e n g t h o f t h e r u n ) . D i v i d e e a c h o f t h e s e v a l u e s by t h e i n i t i a l w e i g h t o f t h e sample t o o b t a i n t h e w e i g h t p e r c e n t o f H20 and C02 i n t h e sample. S u b t r a c t t h e f i n a l w e i g h t o f t h e c o m b u s t i o n b o a t p l u s sample f r o m t h e i n i t i a l v a l u e and d i v i d e by t h e i n i t i a l w e i g h t o f t h e sa m p l e , t o o b t a i n t h e t o t a l w e i g h t p e r c e n t o f sample l o s t . T h i s v a l u e s h o u l d a g r e e w i t h t h e sum o f t h e H20 and C02 t o w i t h i n 5%. I f n o t , a d u p l i c a t e r u n s h o u l d be made. S h u t Down: T u r n down v o l t a g e on v a r i a c and s w i t c h o f f . R e l e a s e p r e s s u r e o f n i t r o g e n by b a c k i n g o f f on r e g u l a t o r . W a i t f o r b u b b l e s t o s t o p i n m i n e r a l b a t h ; t h e n c l o s e n e e d l e v a l v e on n i t r o g e n r e g u l a t o r and main p r e s s u r e v a l v e on t a n k , and s h u t a l l v a l v e s on d r y i n g t u b e s . T h i s i n s u r e s t h a t no a i r w i l l e n t e r t h e s y s t e m and t h a t n i t r o g e n p r e s s u r e w i l l n o t b u i l d up w i t h i n t h e s y s t e m . F i g u r e C - l d e p i c t s t h e a p p a r a t u s u s e d i n w a t e r and C a r b o n d i o x i d e a n a l y s e s . FIGURE C-I: Schematic drawing of apparatus used for determination of t o t a l H„0 and CO,.. APPENDIX D FLUID INCLUSION GEOTHERMOMETRY ANALYTICAL TECHNIQUES 207 APPENDIX D-1: SAMPLE PREPARATION AND DOCUMENTATION ( A f t e r Bloom, 1979) A c o m p r e h e n s i v e o u t l i n e f o r p r e p a r a t i o n o f sample c h i p s f o r f l u i d i n c l u s i o n s t u d y i s beyond t h e s c o p e o f t h i s r e p o r t . The t e c h n i q u e s u s e d a r e g e n e r a l l y t h o s e r e p o r t e d i n H o l l a n d e t a l . (1978) and Roedder ( 1 9 7 6 ) . The s e l e c t i o n and d o c u -m e n t a t i o n o f i n c l u s i o n g r o u p s and s p e c i f i c i n c l u s i o n s f o r h e a t i n g / f r e e z i n g s t u d i e s s h o u l d f o l l o w t h e b a s i c o u t l i n e g i v e n b e l o w . 1. T h o r o u g h e x a m i n a t i o n and i d e n t i f i c a t i o n o f t h e t y p e , a bundance, and d i s t r i b u t i o n o f f l u i d i n c l u s i o n s . C o n s i d e r a t i o n s h o u l d be g i v e n t o s u c h p r o b l e m s as s p a t i a l and t e m p o r a l r e l -a t i o n s h i p s ; p r i m a r y , p s e u d o - s e c o n d a r y , o r s e c o n d a r y o r i g i n ; l e a k a g e and n e c k i n g down; i d e n t i f i c a t i o n o f a l l p h a s e s , n o t i n g p a r t i c u l a r l y t h e p r e s e n c e o f l i q u i d CO a n d / o r d a u g h t e r m i n e r a l s ; m o r p h o l o g y ; d e g r e e o f f i l l , s i z e , e t c . Much u s e f u l i n f o r m a t i o n c a n be o b t a i n e d f r o m t h i s e x e r c i s e l o n g b e f o r e t h e h e a t i n g / f r e e z i n g s t u d i e s a r e begun. E x c e l l e n t s t u d i e s i n d e s c r i p t i v e f l u i d i n c l u s i o n p e t r o l o g y i n c l u d e Nash ( 1 9 7 6 ) , K e l l y and T e n e u r e ( 1 9 7 0 ) , and Roedder ( 1 9 7 2 ) . C r i t e r i a f o r s e l e c t i o n o f s p e c i f i c i n c l u s i o n s f o r f u r t h e r work s h o u l d i n c l u d e r e p r e s e n t a t i v e examples o f e a c h i n c l u s i o n t y p e and r e l a t i v e age, unambiguous o r i g i n ( p r i m a r y when p o s s i b l e ) , c l a r i t y o f h o s t m i n e r a l ( i s o l a t e d i n c l u s i o n s o r i n c l u s i o n g r o u p s w i t h o u t a d j a c e n t f r a c t u r e s o r s o l i d i n c l u s i o n s a r e d e s i r a b l e ) , e t c . R e l o c a t i n g an i n c l u s i o n , p a r t i c u l a r l y i n 208 a l a r g e p l a t e crowded w i t h i n c l u s i o n s , c an be m o n u m e n t a l l y a g g r a v a t i n g . A s e r i e s o f p h o t o g r a p h s , b e g i n n i n g w i t h a m a c r o p h o t o g r a p h showing t h e r e l a t i o n o f t h e sample c h i p t o t h e e n t i r e p l a t e and e n d i n g w i t h a p h o t o m i c r o g r a p h s h owing t h e i n c l u s i o n s as t h e y w i l l a p p e a r d u r i n g t h e h e a t i n g / f r e e z -i n g work, e l i m i n a t e s much o f t h i s f r u s t r a t i o n . S c r i b i n g a f a i n t c i r c l e a r o u n d t h e a r e a o f i n t e r e s t w i t h a diamond s t y l u s i s a l s o q u i t e u s e f u l . 3. C u t i n d i v i d u a l sample c h i p ( s ) f r o m t h e f l u i d i n c l u s i o n p l a t e s . T h i s i s b e s t a c c o m p l i s h e d w h i l e t h e p l a t e i s s t i l l mounted on a g l a s s s l i d e by s c o r i n g t h e p l a t e w i t h a s m a l l diamond a b r a s i v e d i s k mounted i n a D r e m e l " M o t o t o o l " ( F i g u r e 1 0 ) . E a c h sample c h i p may be c u t i n t h e shape o f an i s o s c e l e s t r i a n g l e , w i t h t h e i n c l u s i o n ( s ) n e a r e s t t h e apex. C a r e s h o u l d be t a k e n t o a d e q u a t e l y c o o l t h e p l a t e w h i l e c u t t i n g , and t o make t h e c u t s a t some d i s t a n c e f r o m t h e i n c l u s i o n ( s ) . 4. P r o c e e d w i t h t h e a c t u a l h e a t i n g / f r e e z i n g s t u d y . Sample c h i p s must f i r s t be removed f r o m t h e i r g l a s s b a c k i n g , u s u a l l y by s o a k i n g i n an o r g a n i c s o l v e n t ( a c e t o n e , x y l e n e , e t c . ) . B e c a u s e f r e e z i n g i s f a r l e s s d e s t r u c t i v e t h a n h e a t i n g work, i t i s a d v i s a b l e t o c o m p l e t e a l l o b s e r v a t i o n s i n t h e f r e e z i n g mode b e f o r e p r o c e e d i n g t o t h e h e a t i n g p h a s e . A c e r t a i n p e r c e n t a g e o f t h e c h o s e n i n c l u s i o n s w i l l be l o s t d u r i n g t h e f r e e z i n g work, p a r t i c u l a r l y i f t h e h o s t m i n e r a l has good c l e a v a g e ( i . e . , f l u o r i t e , c a l c i t e , e t c . ) . The l o s s due t o d e c r e p i t a t i o n d u r i n g h e a t i n g r u n s w i l l be even g r e a t e r , 209 s o i t i s w i s e t o have p r e p a r e d d u p l i c a t e sample c h i p s f r o m e a c h p l a t e . D o c u m e n t a t i o n d u r i n g t h e f r e e z i n g / h e a t i n g i s somewhat o f a p r o b l e m i n t h a t p h o t o g r a p h s do n o t a d e q u a t e l y r e p r e s e n t t h e d e p t h o f t h e sample c h i p s . A s e r i e s o f s k e t c h e s o f t h e a r e a as s e e n t h r o u g h t h e m i c r o s c o p e a t one o r more s t a g e s o f mag-n i f i c a t i o n i s p a r t i c u l a r l y u s e f u l . T h o s e i n c l u s i o n s w h i c h w o u l d be i n p o o r f o c u s i n a p h o t o g r a p h c a n t h u s be r e l a t e d t o r e c o g n i z a b l e f e a t u r e s a n d / o r o t h e r i n c l u s i o n s i n t h e c h i p . The most i m p o r t a n t t e c h n i q u e t o m a s t e r d u r i n g h e a t i n g / f r e e z i n g r u n s i s t o a p p r o a c h t h e " h o m o g e n i z a t i o n " t e m p e r a t u r e ( s ) a t a v e r y s l o w and c o n s i s t e n t h e a t i n g / c o o l i n g r a t e . The o p e r -a t o r i s t h e n a t l e i s u r e t o s c a n t h e e n t i r e f i e l d o f v i e w a t v a r i o u s d e p t h s i n t h e c h i p , and r e c o r d t h e h o m o g e n i z a t i o n b e h a v i o r o f a l a r g e number o f i n c l u s i o n s r a t h e r t h a n a s e l e c t e d few. A v a r i e t y o f i m p o r t a n t d a t a s h o u l d be c o l l e c t e d d u r i n g t h e h e a t i n g / f r e e z i n g s t u d i e s . I n t h e f r e e z i n g mode, t h e p r e s e n c e o f l i q u i d CC^ c a n be c o n f i r m e d a t t h e t r i p l e p o i n t o f CO 2 (-56°C). Of more g e n e r a l i n t e r e s t t o most u s e r s , however, i s measurement o f t h e f r e e z i n g p o i n t d e p r e s s i o n , t a k e n a s t h e d i s a p p e a r a n c e o f t h e l a s t i c e c r y s t a l . T h i s measurement i s o f t e n q u i t e d i f f i c u l t t o o b s e r v e . I n t h e h e a t i n g mode, t h e t e m p e r a t u r e o f CO2 h o m o g e n i z a t i o n ( i f l i q u i d CO2 i s p r e s e n t ) and t h e d i r e c t i o n o f t h i s homogen-i z a t i o n (CO- e x p a n d i n g o r s h r i n k i n g ) o c c u r s a t a maximum o f 210 32°C. T h r o u g h o u t t h e h e a t i n g r a n g e , t h e h o m o g e n i z a t i o n b e -h a v i o r o f a l l p h a s e s s h o u l d be r e c o r d e d . T h i s i n c l u d e s t h e f i l l i n g t e m p e r a t u r e and d i r e c t i o n o f f i l l ( l i q u i d - h o m o g e n i z i n g o r v a p o r - h o m o g e n i z i n g ) and t h e d i s s o l u t i o n t e m p e r a t u r e o f t h e c o n t a i n e d d a u g h t e r m i n e r a l s . APPENDIX D-2: S/AMPLE HEATING PROCEDURE The h e a t i n g and f r e e z i n g s t a g e and i t s a s s p c i a t e d i n s t r u -m e n t a t i o n i s d e p i c t e d i n P l a t e D-1. 1. T u r n t h e main power sw i t c h , on and a l l o w t h e c o n t r o l c o n s o l e t o s t a b i l i z e f o r a p p r o x i m a t e l y 15 m i n u t e s . W i t h t h e power on, t h e r e a d o u t s h o u l d i n d i c a t e room t e m p e r a t u r e . P r o -c e d u r e s f o r c a l i b r a t i o n o f t h e t e m p e r a t u r e r e a d o u t a r e g i v e n i n t h e C h a i x m e c a m a n u a l . 2. Be s u r e t h a t a l l p l a s t i c t u b i n g u s e d i n t h e f r e e z i n g mode o f o p e r a t i o n a r e d i s c o n n e c t e d f r o m t h e h e a t i n g s t a g e . Mount t h e sample i n s i d e t h e s t a g e . F o r h i g h t e m p e r a t u r e work, t h e s t a g e has been c a l i b r a t e d w i t h a p y r o p h y l l i t e d i s k r e p l a c -i n g t h e c o v e r g l a s s . T h i s m o d i f i c a t i o n has g r e a t l y i m p r o v e d t h e v i s i b i l i t y o f m i n u t e i n c l u s i o n s . I f you p r e f e r t h e s i l i c a d i s k , i t w i l l be n e c e s s a r y t o r e c a l i b r a t e t h e h i g h - t e m p e r a t u r e r a n g e ! 3. P l a c e t h e aluminum f o i l " f i l l e r " a r o u n d t h e o b j e c t i v e l e n s and t h e c o o l i n g c o i l a r o u n d t h e " f i l l e r " . Two c o o l i n g c o i l s a r e a v a i l a b l e — o n e d e s i g n e d f o r t h e L e i t z H32 h i g h -t e m p e r a t u r e l e n s and t h e o t h e r f o r t h e UMK-50 u n i v e r s a l s t a g e l e n s . The c h o i c e o f o b j e c t i v e l e n s i s a m a t t e r o f p r e -f e r e n c e , d i c t a t e d i n l a r g e p a r t by t h e optimum c o n d i t i o n s f o r v i e w i n g y o u r i n c l u s i o n s . I have f o u n d t h e UMK-50 i n combin-a t i o n w i t h l O x and 16x o c u l a r s b e s t . I f y o u r i n c l u s i o n s a r e q u i t e l a r g e and y o u p r e f e r a d i f f e r e n t o b j e c t i v e l e n s , i t i s 212 a b s o l u t e l y n e c e s s a r y t h a t a c o o l i n g c o i l i s c o n s t r u c t e d t o f i t y o u r c h o i c e o f l e n s . 4. The c o o l i n g w a t e r r e s e r v o i r s h o u l d be f i l l e d w i t h i c e w a t e r , and t h e w a t e r t e m p e r a t u r e m a i n t a i n e d b e l o w 35°C t o a v o i d damage t o t h e o b j e c t i v e l e n s . W i t h t h e r e s e r v o i r f u l l , t h e s u b m e r s i b l e pump c a n be t u r n e d on. The pump s h o u l d n o t be a l l o w e d t o o p e r a t e when d r y ! 5. The mode o f o p e r a t i o n — m a n u a l o r a u t o m a t i c - — m u s t be s e l e c t e d . U n der manual o p e r a t i o n , t h e r h e o s t a t c o n t r o l s t h e maximum t e m p e r a t u r e , w h i l e i n a u t o m a t i c mode t h e p r e s e t c o n -t r o l l e r d e t e r m i n e s t h e maximum o p e r a t i n g t e m p e r a t u r e . I n e i t h e r c a s e , t h e h e a t i n g r a t e I s c o n t r o l l e d by t h e t e m p e r a t u r e d i f f e r e n c e between t h e s t a g e and t h e h e a t i n g c a p a c i t y o f t h e r h e o s t a t . F o r manual o p e r a t i o n , t h e m a n u a l / a u t o m a t i c s w i t c h s h o u l d be i n t h e manual mode, t h e h e a t i n g s w i t c h s h o u l d be t u r n e d on, and t h e r h e o s t a t s h o u l d be s e t t o t h e d e s i r e d l e v e l . F o r a u t o m a t i c o p e r a t i o n , t h e c o n t r o l l e r s h o u l d be s e t t o t h e a p p r o x i m a t e d e s i r e d t e m p e r a t u r e and t h e a u t o / m a n u a l s w i t c h must be i n t h e " a u t o " mode, and t h e r h e o s t a t s h o u l d be s e t f o r t h e d e s i r e d h e a t i n g r a t e . The e x p e r i e n c e d o p e r a t o r w i l l f i n d t h e a u t o m a t i c mode o f o p e r a t i o n q u i t e e f f i c i e n t , as t h e s t a g e c a n be r a p i d l y b r o u g h t t o a d e s i r e d t e m p e r a t u r e and m a i n t a i n e d a t t h a t s e t t i n g I n -d e f i n i t e l y . H i g h h e a t i n g r a t e s a r e n o t a d v i s e d , however, b e c a u s e t h e s t a g e t e m p e r a t u r e c a n e a s i l y " o v e r s h o o t " t h e p r e -s e t maximum and p o t e n t i a l l y c a u s e damage t o t h e sample C i . e . , d e c r e p i t a t i o n o f t h e c o n t a i n e d f l u i d i n c l u s i o n s ) . I t I s b e s t t o m a i n t a i n t h e r m a l e q u i l i b r i u m t h r o u g h o u t t h e h e a t i n g r u n . The b e g i n n i n g o p e r a t o r i s a d v i s e d t o u s e t h e manual mode o f o p e r a t i o n and s l o w h e a t i n g r a t e s u n t i l he i s f a m i l i a r with, t h e b e h a v i o r o f t h e s t a g e and h i s s a m p l e s . R h e o s t a t and s w i t c h s e t t i n g s c an be v a r i e d d u r i n g r u n s w i t h o u t damage. I n manual mode, t h e h e a t i n g s w i t c h , and t h e c o o l i n g s w i t c h s h o u l d n o t be on s i m u l t a n e o u s l y . T h e s e s w i t c h e do n o t a f f e c t t h e o p e r a t i o n o f t h e s t a g e i n t h e a u t o m a t i c mode F o r r e l a t i v e l y s t a b l e t e m p e r a t u r e s o r low h e a t i n g r a t e s a t h i g h e r t e m p e r a t u r e s , i t i s b e s t t o c o n t r o l t h e s t a g e r e s p o n s e w i t h t h e r h e o s t a t s e t t i n g (manual mode). 6. F o r shutdown, t u r n t h e r h e o s t a t down f i r s t . T h en, i n t h e manual mode, move h e a t i n g s w i t c h t o o f f , o r , i n t h e a u t o mode, r e s e t t h e c o n t r o l l e r t o room t e m p e r a t u r e . A l l o w t h e s t a g e t o c o o l t o a p p r o x i m a t e l y 50°C b e f o r e s h u t t i n g o f f t h e c i r c u l a t i n g pump. APPENDIX D-3:. SAMPLE FREEZING PROCEDURE 1. As w i t h h e a t i n g u s e , t h e c o n t r o l c o n s o l e s h o u l d be s w i t c h e d on a t l e a s t 15 m i n u t e s p r i o r t o u s e . . 2. Check c o n n e c t i o n s f o r gas f l o w t h r o u g h s t a g e . Tube A s h o u l d be c o n n e c t e d t o t h e c o n t r o l c o n s o l e o u t l e t and t h e c o o l i n g c o i l i n l e t . Tube B, w i t h a 15 p s i c h e c k v a l v e , c o n -n e c t s t o t h e c o o l i n g c o i l o u t l e t and t h e s t a g e i n l e t ( t h e l o w e r p a r t o f t h e s t a g e , away f r o m t h e o p e r a t o r ) . Tube C, the e x i t t u b e , c o n n e c t s t o the s t a g e o u t l e t Cthe u p p e r p a r t o f the s t a g e , n e a r e r the o p e r a t o r ) , and may be d i r e c t e d i n t o the p o l y s t y r e n e i n s u l a t i o n between the l i g h t s o u r c e and the s t a g e . T h i s r e d u c e s c o n d e n s a t i o n o f H^O and C 0 2 on t h e l o w e r c o n d e n s i n g l e n s and t h e s u r f a c e o f t h e s t a g e . 3. S t a r t gas f l o w t h r o u g h t h e s y s t e m a t a low f l o w r a t e t o d r y o u t r e s i d u a l m o i s t u r e i n t h e s t a g e and t o c h e c k f o r c o n d e n s a t i o n i n t h e c o o l i n g c o i l . To s t a r t t h e gas f l o w , open t h e v a l v e on t h e d r y n i t r o g e n c y l i n d e r , t h e n open t h e r e g u l a t o r t o a d e l i v e r y p r e s s u r e o f 10-15 p s i . " S p u t t e r i n g " o f t h e gas f l o w i n d i c a t e s p r e s e n c e o f m o i s t u r e i n t h e s y s t e m w h i c h must be e l i m i n a t e d by p a s s i n g c o m p r e s s e d a i r t h r o u g h t h e c o o l i n g c o i l and s t a g e . The n e e d l e v a l v e on t h e gas f l o w m e t e r must a l s o be opened; t h i s opens t h e gas l i n e t o t h e c o n t r o l l e r . 4. S e t a u t o m a t i c o r ma n u a l mode on t h e c o n t r o l l e r . When t h e s w i t c h i s on i n t h e manual mode, gas s h o u l d f l o w t h r o u g h 215 t h e e n t i r e s y s t e m . N e e d l e v a l v e i s b e s t f o r c o n t r o l o f t h e c o o l i n g / h e a t i n g r a t e . I n t h e manual mode, minimum t e m p e r a t u r e i s d e t e r m i n e d by f l o w r a t e . I n t h e a u t o m a t i c mode, gas f l o w i s i n i t i a t e d by s e t t i n g t h e c o n t r o l l e r b e l o w s t a g e t e m p e r a t u r e . Minimum t e m p e r a t u r e i s s e t by t h e c o n t r o l l e r o r t h e gas f l o w r a t e . 5. Mount sample i n s t a g e and p l a c e t h e i s o l a t i o n a d a p t o r and i n s u l a t i o n s h e l l a r o u n d t h e s t a g e and o b j e c t i v e . C o o l i n g c a n be done w i t h o r w i t h o u t t h e s i l i c a d i s k on t h e sample chamber; c a l i b r a t i o n c u r v e s a r e f o r work w i t h o u t t h e d i s k . 6. When r e a d y t o b e g i n c o o l i n g , f i l l t h e c o o l i n g - c o i l dewar w i t h l i q u i d n i t r o g e n ( a v a i l a b l e f r o m t h e g e o c h r o n o l o g y l a b o r a t o r y ) . 7. I n i t i a l f r e e z i n g i s a c c o m p l i s h e d by a r a p i d gas f l o w t h r o u g h t h e s y s t e m o r by c o m p l e t e l y i m m e r s i n g t h e sample c h i p i n l i q u i d n i t r o g e n . I t i s g e n e r a l l y n e c e s s a r y t o s u p e r c o o l t h e sample t o t e m p e r a t u r e s f a r b e l o w t h e m e l t i n g p o i n t o f tfte i n c l u s i o n f l u i d . S low warming I s a c h i e v e d by v a r y i n g t h e g a s f l o w r a t e w i t h t h e n e e d l e v a l v e on t h e c o n t r o l l e r . R a p i d warm-i n g c a n be a c h i e v e d by t u r n i n g t h e gas f l o w o f f and t u r n i n g t h e h e a t i n g u n i t on ( t h e r h e o s t a t s e t t i n g s h o u l d n o t e x c e e d 3 ) . I t i s p r e f e r a b l e t o m a i n t a i n a low f l o w r a t e t h r o u g h t h e gas l i n e t o a v o i d p l u g g i n g and s u c k - b a c k , b u t gas f l o w i s n o t m a i n t a i n e d I n t h e h e a t i n g mode. 8 . Shut-down o f the gas system i s a c h i e v e d by r e s e t t i n g the c o n t r o l l e r , by c l o s i n g the n e e d l e v a l v e o r by s w i t c h i n g the c o o l i n g mode o f f . The gas l i n e s h o u l d be v e n t e d p r i o r t o shutdown by c l o s i n g the v a l v e when gauges on t h e n i t r o g e n t a n k show z e r o p r e s s u r e , the r e g u l a t o r s h o u l d be backed o f f and t h e system i s o l a t e d by c l o s i n g the n e e d l e v a l v e on the c o n t r o l l e r . PLATE D - l : Chaixmeca h e a t i n g and f r e e z i n g stage mounted on an Orthol u x I I b i n o c u l a r microscope. to I—1 218 APPENDIX D-4; DATA INTERPRETATION H e a t i n g and f r e e z i n g work p r o v i d e d a t a on the c o m p o s i t i o n of f l u i d i n c l u s i o n s and the c o n d i t i o n s o f entrapment. I n add-i t i o n t o t h e i n f o r m a t i o n d e r i v e d from g e n e r a l m i c r o s c o p y (degree of f i l l and i n c l u s i o n d e n s i t y , q u a l i t a t i v e e s t i m a t e o f c o m p o s i t i o n from daughter m i n e r a l assemblages, e t c . ) , d a t a on f l u i d s a l i n i t y , approximate CO c o n t e n t , and t e m p e r a t u r e / p r e s s u r e o f entrapment are d e r i v e d from f r e e z i n g and homo-g e n i z a t i o n t e s t s . C a l c u l a t i o n o f s a l i n i t y from the f r e e z i n g d a t a u t i l i z e s t h e known f r e e z i n g p o i n t d e p r e s s i o n (fpd) o f aqueous NaCl s o l u t i o n s . F o r i n c l u s i o n s w h i c h do not have h a l i t e d a u g h t e r m i n e r a l s , the s a l i n i t y i n N a C l - e q u i v a l e n t c o n c e n t r a t i o n s i s r e a d i l y o b t a i n e d . E q u a t i o n s f o r t h e f p d ( i . e . , 9 = 0 - f r e e z -i n g p o i n t ) are g i v e n below: 9 = 0.00+0.581855W +3.48896x10- W +4.314x10- W + 0.03°C W = 0.00+1.769589-4.2384x10- 9 +5.2778x10- 9 + 0.028 where 9 i s the f p d and W i s t h e w e i g h t p e r c e n t N a C l e q u i v a l e n t . D e t a i l e d d i s c u s s i o n o f t h e s e e q u a t i o n s i s a v a i l a b l e i n P o t t e r e t a l . (1977). S a l i n i t y e s t i m a t e s based on NaCl f p d are sub-j e c t t o i n c r e a s i n g e r r o r s as t h e r a t i o o f NaCl t o o t h e r d i s -s o l v e d s p e c i e s ( p a r t i c u l a r l y d i v a l e n t c a t i o n s ) d e c r e a s e s , s i n c e t h e f p d of aqueous s o l u t i o n s i n c r e a s e s w i t h i o n i c s t r e n g t h . More a c c u r a t e e s t i m a t e s o f s a l i n i t y can be o b t a i n e d by o b s e r v i n g the f p d o f s y n t h e t i c s o l u t i o n s a p p r o x i m a t i n g t h e c o m p o s i t i o n o f the i n c l u s i o n s b e i n g s t u d i e d ( c f . Clynne and 219 P o t t e r , 1977). S m a l l e r e r r o r s i n s a l i n i t y e s t i m a t e s can a l s o r e s u l t from h i g h i n t e r n a l p r e s s u r e s i n the i n c l u s i o n examined; such p r e s s u r e s can be e x p e c t e d when l i q u i d CO i s p r e s e n t . F r e e z i n g d a t a can a l s o c o n f i r m the p r e s e n c e o f s o l i d NaCl when the o p t i c a l c h a r a c t e r o f s u s p e c t d a u g h t e r m i n e r a l s cannot be d e t e r m i n e d . The p r e s e n c e o f NaCl-2H 20 i s d e t e c t a b l e b o t h by i t s c h a r a c t e r i s t i c m e l t i n g b e h a v i o r (prisms c l u s t e r e d u s u a l l y around a s o l i d NaCl c o r e , m e l t i n g near 0°C) and i t s h i g h b i r e f r i n g e n c e . Low t e m p e r a t u r e work i s v e r y u s e f u l i n c o n f i r m i n g the p r e s e n c e o f C 0 2 i n f l u i d i n c l u s i o n s . The C 0 2 t r i p l e p o i n t (-56.6°C) i s o b s e r v a b l e i n most i n c l u s i o n s con-t a i n i n g h i g h mole f r a c t i o n s o f C 0 2 , and the r e l a t i v e amount o f C 0 2 i n aqueous i n c l u s i o n f l u i d s can be e s t i m a t e d from t h e C 0 2 c l a t h r a t e h y d r a t e (C0 2.5 3/4 H 20) m e l t i n g t e m p e r a t u r e . For comprehensive d i s c u s s i o n s o f t h e C-O-H-NaCl system, see H o l l i s t e r and B u r r e s s (1976) and Swanenberg (1979). Other m o l e c u l e s o f i n t e r e s t i n f l u i d i n c l u s i o n work (H^S, S 0 2 , and hydrocarbons) a l s o form c l a t h r a t e h y d r a t e s t h a t m e l t between 0°C and 20°C, and may p r o v i d e a d d i t i o n a l c o n f u s i o n as w e l l as i n f o r m a t i o n . F o r more c o n c e n t r a t e d f l u i d s w h i c h c o n t a i n h a l i t e d aughter m i n e r a l s (NaCl w e i g h t % e q u i v a l e n t 2 6 ) , s a l i n i t y i s c a l c u l a t e d by o b s e r v i n g the t e m p e r a t u r e o f h a l i t e d i s s o l u t i o n d u r i n g h e a t -i n g t e s t s ( F i g u r e 1 0 ) . The r e g r e s s i o n e q u a t i o n g i v e n b e l o w i s a l e a s t squares f i t t o the combined s o l u b i l i t y d a t a o f P o t t e r and Clynne (1978), L i n k e (1965), and K e e v i l (1946): 220 W = 26.3146+4.13x10- T(°C)+1.12x10- T(°C) where W" i s the weight percent NaCl equivalent. The temper-ature of d i s s o l u t i o n i s f a i r l y sensitive to NaCl concentrations, and i s not strongly pressure-dependent. The homogenization temperature i s also obtained from heating experiments. Homogenization where daughter minerals are present can occur by one of two p r o c e s s e s — f i l l i n g of the inclu s i o n volume by l i q u i d or vapour ( i t i s important to note whether th i s i s liquid-homogenizing or vapour-homogenizing), or d i s s o l u t i o n of the contained daughter mineral(s) a f t e r liquid-vapour f i l l i n g . The homogenization order has a s i g -n i f i c a n t e f f e c t on interpretation of the data (Bloom, 1979; Erwood et a l . , 1979). The homogenization data (corrected for the calib r a t e d deviations) can then be used to d i r e c t l y estimate the pressure of entrapment (Sourirajan and Kennedy, 19 62) if_ there i s evidence that the f l u i d s were b o i l i n g . Cunningham (1978) has reviewed b o i l i n g and i t s effects on f l u i d i n c l u s i o n populations. If evidence for b o i l i n g conditions i s not present, the observed homogenization temperature(s) are minimum estimates of the true entrapment temperature(s) and a pressure correction i s required. The true entrapment temperatures can be calculated i f the degree of f i l l and the s a l i n i t y are known, and i f the pressure at the time of formation can be independently determined. Pressure corrections are greatest for inclusions of low s a l i n i t y and moderately high ( 70%) degrees of f i l l , and 221 become v e r y s m a l l f o r v e r y s a l i n e s o l u t i o n s . C o r r e c t i o n p r o -cedures a r e g i v e n by Lemmlein and K l e v t s o v (1961) and P o t t e r (1977). I n c l u s i o n s t h a t show c r i t i c a l degrees o f f i l l p r o v i d e d a t a from w h i c h b o t h t h e te m p e r a t u r e and p r e s s u r e o f entrapment can be d i r e c t l y c a l c u l a t e d , g i v e n t h a t a good e s t i m a t e of f l u i d s a l i n i t y i s a v a i l a b l e . 222 APPENDIX E X-RAY DIFFRACTION ANALYSES TABLE E - l : X-RAY DIFFRACTION ANALYSES Sample Number M i n e r a l s I d e n t i f i e d 1093 q u a r t z - d i c k i t e - a l u n i t e - i l l i t e 1094 q u a r t z - k a o l i n i t e - m o n t m o r i l l o n i t e 1097 q u a r t z - b a r i t e - k a o l i n i t e - d i c k i t e 1098 q u a r t z - i H i t e - a l u n i t e 1150 q u a r t z - d i c k i t e - k a o l i n i t e 1145 l a u m o n t i t e - n a t r o l i t e - c a l c i t e 1081 f l u o r i t e - l a u m o n t i t e - c a l c i t e 1117 l a u m o n t i t e - c a l c i t e 1159 b a r i t e - q u a r t z - c a l c i t e 1086 k a o l i n i t e - d i c k i t e - q u a r t z 1082 q u a r t z - k a o l i n i t e - d i c k i t e 1167 q u a r t z - i l l i t e - k a o l i n i t e 1134 q u a r t z - o r t h o c l a s e - c h l o r i t e Note: F o r Sample l o c a t i o n s see P l a t e I T. APPENDIX F PETROGRAPHIC DESCRIPTIONS TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: I O Z I Rock Name: p^ronene a««i*»i+c. 4^k& Geological Unit: 2.3 B. MAJOR ELEMENTS S102 Ti02 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 o.81 5.as o.lS 701 7-31 2.n 3./fe 0 . 0 2 3.61 '•37 C. TRACE ELEMENTS Ni Cr V Sr Rb Ba Zr Nb Th Cu Au Ag D. PETROGRAPHIC DESCRIPTIONS Eruptive Type/Mode of Occurrence ash flow agglomerate b r e c c i a • dyke flow b r e c c i a nuee ardente p y r o c l a s t i c Texture/Structures v^amygdular aph a n i t i c banded brecciated coarse d e v i t r i f i e d e u t a x i t i c embayed phenocrysts equigranular fiamme f i n e flow banded f o l i a t e d s i l l stock t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c welded t u f f glomerporphyritic graded bedding g r a n i t i c graphic hyp i d iomo rphic massive m i c r o c r y s t a l l i n e mineral pseudomorphs | r * p o r p h y r i t i c pumiceous veined t r a c h y t i c v e s i c u l a r State of Preservation f r e s h -f a l t e r e d r l . s l i g h t l y 2. moderately 3. extensively Type o f A l t e r a t i o n a r g i l l i c c a r b o n a t i c y/ c h l o r i t i c d e u t e r i c h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s >/ p l a g i o c l a s e — * s e r i c i t e ^ p l a g i o c l a s e — * c h l o r i t e p l a g i o c l a s e — • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — • q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — * s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — • opaques h o r n b l e n d e — + p r e h n l t e h o r n b l e n d e — » q u a r t z b i o t i t e — * e p i d o t e + c h l o r i t e b i o t i t e — • c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques >f c l i n o p y r o x e n e - ^ opaques M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : 2 5 % g r o u n d m a s s : 1 ^ £ | p l a g i o c l a s e An c o n t : Ahg^ q u a r t z o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e | i r o n o x i d e h e m a t i t e 2. m a g n e t i t e p y r i t e 7 c h l o r i t e e p i d o t e Q c a r b o n a t e p r e h n i t i c p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c % 3 s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s 227 TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: 10^,3 Rock Name: V\orr>\>\en<\e dr\c)UL*\V-C Geological Unit: Q \\txvc\Wi §ro^ B. MAJOR ELEMENTS Si02 Ti02 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 M.31 o.i8 M l * 3.18 o.il ©.SO TRACE ELEMENTS Ni Cr V Sr Rb Ba Zr Nb Th Cu Au Ag 37 *X1 *81 »#© # Wo too 3b 2/ a. D. PETROGRAPHIC DESCRIPTIONS Eruptive Type/Jfode of Occurrence ash flow agglomerate b r e c c i a dyke \/ flow/br ecc i a nuee ardente p y r o c l a s t i c Texture/Structures amygdular • a p h a n i t i c banded brecciated coarse d e v i t r i f i e d e u t a x i t i c embayed phenocrysts equigranular fiamme f i n e ^ f l o w banded f o l i a t e d s i l l stock t u f f t u f f b r e c c i a vein. vo1canoclas t i c welded t u f f glomerporphyritic graded bedding g r a n i t i c graphic hypidiomorphic massive m i c r o c r y s t a l l i n e ^ m i n e r a l pseudomorphs • p o r p h y r i t i c pumiceous is veined - Q u a r V l , Ccu-bort«te. t r a c h y t i c v e s i c u l a r State of Preservation f r e s h Yaltered | / l . s l i g h t l y 2. moderately 3. extensively Type of A l t e r a t i o n a r g i l l i c p r e h n i t i c S carbonatic p r o p y l i t i c • c h l o r i t i c • s e r i c i t i c d euteric s i l i c i f i c a t i o n >f hydrothermal z e o l i t i c leached potassic Mineral A l t e r a t i o n s and Replacements ^ p l a g i o c l a s e — • s e r i c i t e  • p l a g i o c l a s e — » c h l o r i t e p l a g i o c l a s e — • epidote + s e r i c i t e + carbonate + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — • quartz p l a g i o c l a s e — • p o t a s s i u m feldspar hematized p l a g i o c l a s e Vr^hematized potassium feldspar potassium feldspar—» s e r e i t e hornblende — * c h l o r i t e + opaques • hornblende—» epidote + c h l o r i t e + opaques hornblende — » opaques hornblende — • prehnite hornblende — » q u a r t z b i o t i t e — * epidote + c h l o r i t e b i o t i t e — * c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques c l i n o p y r o x e n e — * opaques Mineral Assemblage % phenocrysts: 3 5 % groundmass: 65 % g 2. I I p l a g i o c l a s e An cont: quartz orthoclase sanidine a d u l a r i a b i o t i t e hornblende b a s a l t i c hornblende clinopyroxene i r o n oxide hematite magnetite p y r i t e c h l o r i t e epidote carbonate % l5" s e r i c i t e | a p a t i t e sphene laumontite d i e k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e glass TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: Rock Name: K o m f e W n d e e m A e ^ i T C G e o l o g i c a l U n i t : $ t 4 a i . e \ V o i 4 Gyroof> B. MAJOR ELEMENTS S i 0 2 5VT1 T i 0 2 0.4>Z AL203 Fe203 3 . 3 1 FeO lt>t> MnO MgO 2. ft CaO s.ui Na20 3.IS K20 Hoi P205 O.J.J C02 o.lo H20 TRACE ELEMENTS N i Cr V S r Rb Ba Z r Nb Th Cu Au Ag 15 «JS /« »7j 3o» 0 26 S on PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w a g g l o m e r a t e b r e c c i a d y k e • f l o w / b r e c c i a nuee a r d e n t e p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e d e v i t r i f i e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iamme f i n e • f l o w banded $t«^M 0 M I J f o l i a t e d s i l l s t o c k t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c hyp i d iomo r p h i c m a s s i v e m i c r o c r y s t a l l i n e m i n e r a l pseudomorphs y / p o r p h y r i t i c pumiceous v e i n e d t r a c h y t i c ^ v e s i c u l a r S t a t e o f P r e s e r v a t i o n f r e s h V a l t e r e d 1. s l i g h t l y V 2 . m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c • c a r b o n a t i c • c h l o r i t i c d e u t e r i c • h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — • s e r i c i t e ^ p l a g i o c l a s e — » c h l o r i t e • p l a g i o c l a s e • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — » q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e • hornb lende—» c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — » opaques h o r n b l e n d e — • p r e h n i t e h o r n b l e n d e • q u a r t z b i o t i t e — ^ e p i d o t e + c h l o r i t e b i o t i t e — » c h l o r i t e c l i n o p y r o x e n e — • c h l o r i t e + opaques c l i n o p y r o x e n e — * opaques M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : ^ ° % g r o u n d m a s s : 10 % iff p l a g i o c l a s e An c o n t : A n ^ q u a r t z o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e (o h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e 2, h e m a t i t e I m a g n e t i t e I p y r i t e I S c h l o r i t e 5 e p i d o t e ^ c a r b o n a t e p r e h n i t i c • p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c % 1» s e r i c i t e + V * I A a p a t i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: 104*"^ Rock Name: V \ o t n b l t n d i e a n d t e s ' i V c Geological Unit: Q Hft-ueWo^ G | r « v ^ B. MAJOR ELEMENTS Si02 61.1*11 Ti02 AL203 Fe203 fe-21 FeO 1-88 MnO MgO 3.l> CaO S8l Na20 K20 P205 C02 H20 TRACE ELEMENTS Ni Cr V Sr Rb Ba Zr Nb Th Cu Au Ag D. PETROGRAPHIC DESCRIPTIONS Eruptive Type/Mode of Occurrence ash flow agglomerate b r e c c i a dyke • flow/breccia nuee ardente p y r o c l a s t i c Texture/Structures amygdular • a p h a n i t i c banded brecciated coarse d e v i t r i f i e d e u t a x i t i c embayed phenocrysts equigranular fiamme f i n e flow banded f o l i a t e d s i l l stock t u f f t u f f b r e c c i a v e i n vo1canoclas t i c welded t u f f glomerporphyritic graded bedding g r a n i t i c graphic hypidiomorphic massive m i c r o c r y s t a l l i n e ^ m i n e r a l pseudomorphs  ^ p o r p h y r i t i c pumiceous veined t r a c h y t i c • v e s i c u l a r State of Preservation f r e s h • a l t e r e d 1. s l i g h t l y V2. moderately 3. extensively 232 Type of A l t e r a t i o n a r g i l l i c p r e h n i t i c y/ carbonatic |/" p r o p y l i t i c c h l o r i t i c • s e r i c i t i c d euteric ^ s i l i c i f i c a t i o n VJtv-j rn»t-»o^  • hydrothermal z e o l i t i c leached potassic Mineral A l t e r a t i o n s and Replacements ^ p l a g i o c l a s e — • s e r i c i t e • p l a g i o c l a s e — > c h l o r i t e p l a g i o c l a s e • epidote + s e r i c i t e + carbonate + a l b i t e p l a g i o c l a s e —*• clays + a l u n i t e p l a g i o c l a s e — » quartz p l a g i o c l a s e — • potassium feldspar • hematized p l a g i o c l a s e hematized potassium feldspar potassium feldspar—» s e r c i t e • h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — * epidote + c h l o r i t e + opaques hornblende — » opaques hornblende — • prehnite hornblende •quartz b i o t i t e — • epidote + c h l o r i t e b i o t i t e — » c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques clinopyroxene—» opaques Mineral Assemblage % phenocrysts: % groundmass: "7 $ % 3 3 p l a g i o c l a s e An cont: Cj quartz «5-X» orthoclase sanidine a d u l a r i a b i o t i t e ^ hornblende b a s a l t i c hornblende clinopyroxene i r o n oxide I hematite 3 magnetite 3. p y r i t e 21 c h l o r i t e X epidote ) 1 » carbonate % ^ s e r i c i t e • + K * u . a P a t i t e sphene laumontite d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e glass TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: |OHO Rock Name: p u m i c e W c c c V e c Geological Unit: 7 VA an.«\VoiO Gy+oo^ B. MAJOR ELEMENTS Si02 Ti02 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 W < 6. Iff V.IO 3 .H o-9y TRACE ELEMENTS Ni Cr V Sr Rb Ba Zr Nb Th Cu Au Ag a aa2 4/ /too 7-r 8 If II to I.O D. PETROGRAPHIC DESCRIPTIONS Eruptive Type/Mode of Occurrence ash flow agglomerate breccia dyke »/" flow breccia is nuee ardente pyroclastic Texture/Structures amygdular aphanitic banded ^ brecciated coarse y d e v i t r i f i e d • e u t a x i t i c """ embayed phenocrysts equigranular • fiamme f i n e flow banded f o l i a t e d s i l l stock t u f f t u f f breccia vein volcanoclastic welded t u f f glomerporphyritic graded bedding g r a n i t i c graphic hyp i d iomo rphic massive mi c r o c r y s t a l l i n e >/ mineral pseudomorphs • porphyritic" • pumiceous veined trachytic vesicular State of Preservation fresh s altered 1. s l i g h t l y >S2. moderately 3. extensively Type o f A l t e r a t i o n a r g i l l i c • c a r b o n a t i c • c h l o r i t i c d e u t e r i c • h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — • s e r i c i t e p l a g i o c l a s e — * c h l o r i t e • p l a g i o c l a s e — • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — • q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r ^ h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques • h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e —»opaques h o r n b l e n d e — * p r e h n i t e h o r n b l e n d e — • q u a r t z b i o t i t e — * e p i d o t e + c h l o r i t e b i o t i t e — * c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques c l i nopyroxene—» opaques p r e h n i t i c W p r o p y l i t i c \y s e r i c i t i c s i l i c i t i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : l\ % g r o u n d m a s s : g<| % 2.3- p l a g i o c l a s e An c o n t : /^\r\0^ 2. q u a r t z o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e h e m a t i t e magnet i t e p y r i t e l b c h l o r i t e 3 e p i d o t e c a r b o n a t e 1 3 % J. s e r i c i t e 4 r * I* a p a t i t e sphene l a u m o n t i t e d i e k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e l y i f g l a s s TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: \01o\ Rock Name: 6 l \ \ C \ ^ e d A n d e ^ v V c Geological Unit: ^ W a t e l V o * Gjrouf B. MAJOR ELEMENTS Si02 Ti02 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 8l <\l 2.x^ OJ3\. o.\o «.31 O. IX a.81 o.xa C. TRACE ELEMENTS Ni Cr V Sr Rb Ba Zr Nb Th Cu Au Ag "3 0 2.1 O O lo S 'fc S"7o t1.» PETROGRAPHIC DESCRIPTIONS Eruptive Type/Mode of Occurrence ash flow agglomerate • breccia dyke • flow/br ecc i a nuee ardente pyroclastic Texture/Structures amygdular aphanitic banded • brecc i a t ed coarse d e v i t r i f i e d e u t a x i t i c embayed phenocrysts equigranular fiamme f i n e flow banded f o l i a t e d s i l l stock t u f f t u f f breccia • vein vo1canoclastic welded t u f f glomerporphyritic graded bedding g r a n i t i c graphic hypidiomorphic massive micr o c r y s t a l l i n e ^ mineral pseudomorphs porphyritic pumiceous •Veined trachytic vesicular State of Preservation fresh •'altered 1. s l i g h t l y 2. moderately extensively Type o f A l t e r a t i o n a r g i l l i c c a r b o n a t i c c h l o r i t i c d e u t e r i c • h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — • s e r i c i t e p l a g i o c l a s e — * c h l o r i t e p l a g i o c l a s e • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e / p l a g i o c l a s e — » q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — * s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — • opaques h o r n b l e n d e — * p r e h n i t e •* h o r n b l e n d e ——»quartz b i o t i t e — * e p i d o t e + c h l o r i t e b i o t i t e — » c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques c l i n o p y r o x e n e — * opaques p r e h n i t i c p r o p y l i t i c s e r i c i t i c • " s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : % g r o u n d m a s s : t«5 B5 Vi— p l a g i o c l a s e An c o n t : fc"7 q u a r t z o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e -Vr»t*. h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e 1~ h e m a t i t e m a g n e t i t e \ p y r i t e 3 c h l o r i t e e p i d o t e c a r b o n a t e % -tva.ee s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s TOODOGGONE RIVER NTS: 94E HEADING INFORMATION Sample Number: Rock Name: p y r o x e n e , a n d L e 4 i l c Geological Unit: \0 l 4 n < U - o r * €\vov/^» B. MAJOR ELEMENTS Si02 Ti02 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 2-83 a.11 3.I.S 3.3* O.O TRACE ELEMENTS Ni Cr V Sr Rb Ba Zr Nb Th Cu Au Ag 7 25 W7 «11 /OO 1 20 IX /» *•* PETROGRAPHIC DESCRIPTIONS Eruptive Type/Mode of Occurrence ash flow agglomerate b r e c c i a dyke • f l o w / b r e c c i a nuee ardente p y r o c l a s t i c Texture/Structures amygdular aphanitic banded brecciated coarse d e v i t r i f i e d e u t a x i t i c embayed phenocrysts equigranular fiamme f i n e ^ f l o w banded f o l i a t e d s i l l stock t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c welded t u f f glomerporphyritic graded bedding g r a n i t i c graphic hypidiomorphic massive m i c r o c r y s t a l l i n e • mineral pseudomorphs • p o r p h y r i t i c pumiceous veined t r a c h y t i c • v e s i c u l a r State of Preservation f r e s h • a l t e r e d V I . s l i g h t l y 2. moderately 3. extensively Type o f A l t e r a t i o n a r g i l l i c \/ c a r b o n a t i c c h l o r i t i c d e u t e r i c Shydrothermal l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — • s e r i c i t e V p l a g i o c l a s e — » c h l o r i t e y/ p l a g i o c l a s e — > e p i d o t e + s e r i c i t e + c a r b o n a t e -1- a l b i t e p l a g i o c l a s e — * c l a y s + a l u n i t e v/ 1 p l a g i o c l a s e — » q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e —-» opaques h o r n b l e n d e — » p r e h n i t e h o r n b l e n d e • q u a r t z b i o t i t e - — » e p i d o t e + c h l o r i t e b i o t i t e — * c h l o r i t e c l i nopyroxene—» c h l o r i t e + opaques c l i nopyroxene—» opaques p r e h n i t i c • p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : H ° % g r o u n d m a s s : (aO % i p l a g i o c l a s e An c o n t : q u a r t z o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e h e m a t i t e m a g n e t i t e -K-ftUL p y r i t e c h l o r i t e e p i d o t e c a r b o n a t e A n 0 . 5 V ft i s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i e k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: \OH"5 B. MAJOR ELEMENTS Si02 Ti02 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 x.ne lU* O.K. »•-»! * 8 l o.ix. 3 . 1 * C. TRACE ELEMENTS Ni Cr V Sr Rb Ba Zr Nb Th Cu Au Ag 6 3* er t O i t P 5« \<\ N II 5 D. PETROGRAPHIC DESCRIPTIONS Eruptive Type/Mode of Occurrence ash flow agglomerate b r e c c i a dyke t u f f b r e c c i a v e i n vo 1 cano c l a s t i c welded t u f f s i l l stock t u f f • f l o w / b r e c c i a nuee araente p y r o c l a s t i c Texture/Structures •amygdular glomerporphyritic graded bedding g r a n i t i c graphic hyp i d iomo rphic massive m i c r o c r y s t a l l i n e a p h a n i t l c banded brecciated coarse d e v i t r i f i e d e u t a x i t i c embayed phenocrysts equigranular fiamme f i n e flow banded f o l i a t e d • v e s i c u l a r y mineral pseudomorphs v> p o r p h y r i t i c pumiceous veined t r a c h y t i c State of Preservation f r e s h • a l t e r e d 1. s l i g h t l y moderately 3. extensively Type o f A l t e r a t i o n a r g i l l i c y/ c a r b o n a t i c • c h l o r i t i c • h y d r o t h e r m p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — * • s e r i c i t e • p l a g i o c l a s e — » c h l o r i t e p l a g i o c l a s e — • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — * c l a y s + a l u n i t e p l a g i o c l a s e — • q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — * s e r c i t e h o r n b l e n d e — • c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — • o p a q u e s h o r n b l e n d e — * p r e h n i t e h o r n b l e n d e — » q u a r t z b i o t i t e — » e p i d o t e + c h l o r i t e b i o t i t e — » c h l o r i t e •* c l i n o p y r o x e n e — * c h l o r i t e + opaques • c l i n o p y r o x e n e — * opaques • p r e h n i t i c ^ p r o p y l i t i c s e r l c l t l c s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : 38 % g r o u n d m a s s : 62-% 30 p l a g i o c l a s e An c o n t : q u a r t z o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e y c l i n o p y r o x e n e i r o n o x i d e *2» h e m a t i t e f fACt , m a g n e t i t e 2. p y r i t e l j _ c h l o r i t e e p i d o t e c a r b o n a t e A * 0-5 % 2. s e r i c i t e 4 , - aK .apa t i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s 1 p r c h n i ^ c TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: 10*5 G Rock Name: ^yyo*en«. a n & e v V c Geological Unit: \0 \\ Ccxe Wo/«a G(/tuo B. MAJOR ELEMENTS S102 Ti02 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 O.HS i l.fto 3 - n t-XO 0.11. X*4o 0.13 * Z 0 TRACE ELEMENTS Ni Cr V Sr Rb Ba Zr Nb Th Cu Au Ag 15" 'X-3 3^ 1 (08o s-1 O 2.8 m r '•3 D. PETROGRAPHIC DESCRIPTIONS Eruptive Type/Mode of Occurrence ash flow agglomerate breccia dyke >/ flow/breccia nuee ardente pyr o c l a s t i c Texture/Structures V^ * amygdular aphanitic banded brecciated coarse d e v i t r i f i e d e u t a x i t i c embayed phenocrysts equigranular fiamme f i n e • flow banded f o l i a t e d State of Preservation s i l l stock t u f f t u f f breccia vein volcanoclastic welded t u f f glomerporphyritic graded bedding g r a n i t i c graphic hyp i d iomo rphic massive mic r o c r y s t a l l i n e • m i n e r a l pseudomorphs • p o r p h y r i t i c -pumiceous veined trachytic vesicular fresh •" altered 1. s l i g h t l y v/2. moderately 3. extensively Type o f A l t e r a t i o n a r g i l l i c \/ c a r b o n a t i c  ^ c h l o r i t i c d e u t e r i c • h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — • s e r i c i t e • ^ p l a g i o c l a s e — » c h l o r i t e • p l a g i o c l a s e — » e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + . a l u n i t e p l a g i o c l a s e — » q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r if h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m Feldspar p o t a s s i u m f e l d s p a r — * s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — • opaques h o r n b l e n d e — • p r e h n i t e h o r n b l e n d e — • q u a r t z b i o t i t e — * e p i d o t e + c h l o r i t e b i o t i t e —» c h l o r i t e • c l inopyroxene—» c h l o r i t e + opaques • c l i n o p y r o x e n e — * opaques M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : V^-% g r o u n d m a s s : 5^ % "X^ p l a g i o c l a s e An c o n t : |yof 10 q u a r t z PoSt>tftw£ o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e 3 c l i n o p y r o x e n e i r o n o x i d e | V h e m a t i t e m a g n e t i t e I p y r i t e 3 ^ c h l o r i t e e p i d o t e | i * c a r b o n a t e p r e h n i t i c • p r o p y l i t i c s e r i c i t i c ^ " s i l i c i f i c a t i o n z e o l i t i c % J, s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i c k l t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s TOODOGGONE RIVER NTS: 94E HEADING INFORMATION Sample Number: lOi-7-• Rock Name: v V x ^ o ^ V C -Geological Unit: MAJOR ELEMENTS S102 I t l l Ti02 O . I S AL203 Fe203 0-51 FeO MnO o.tU MgO o.3X. CaO Na20 2-86 K20 P205 C02 H20 /••o| TRACE ELEMENTS Ni Cr V Sr Rb Ba Zr Nb Th Cu Au Ag w n 323 6 a. O S" PETROGRAPHIC DESCRIPTIONS Eruptive Type/Mode of Occurrence ash flow agglomerate b r e c c i a i/dyke tiow b r e c c i a nuee ardente p y r o c l a s t i c Texture/Structures amygdular aphanitic banded brecciated coarse d e v i t r i f i e d e u t a x i t i c • embayed phenocrysts  y equigranular f iamme f i n e • flow banded f o l i a t e d s i l l stock t u f f t u f f b r e c c i a v e i n vo1canoclas t i c welded t u f f glomerporphyrit i c graded bedding g r a n i t i c graphic hypidiomorphic massive m i c r o c r y s t a l l i n e mineral pseudomorphs p o r p h y r i t i c pumiceous veined t r a c h y t i c v e s i c u l a r State of Preservation • ' f r e s h a l t e r e d 1. s l i g h t l y 2. moderately 3. extensively 244 S p e c i a l Note For Sample 1022 - R h y o l i t e T h i s sample showed s i g n s o f e x t e n s i v e w e a t h e r i n g , and thus may not be a r e p r e s e n t a t i v e sample o f t h i s u n i t . Type o f A l t e r a t i o n a r g i l l i c p r e h n i t i c c a r b o n a t i c p r o p y l i t i c ychloritic s e r i c i t i c d e u t e r i c s i l i c i f i c a t i o n h y d r o t h e r m a l z e o l i t i c l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — • s e r i c i t e ^ p l a g i o c l a s e — » c h l o r i t e p l a g i o c l a s e — • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — * q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — » opaques h o r n b l e n d e — * p r e h n i t e h o r n b l e n d e • q u a r t z b i o t i t e — » e p i d o t e + c h l o r i t e b i o t i t e —» c h l o r i t e c l i n o p y r o x e n e — • c h l o r i t e + opaques c l i nopyroxene—» opaques M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : l £ % g r o u n d m a s s : 7"S* % % ^ p l a g i o c l a s e Ar c o n t : A n - j *j s e r i c i t e 5 8 q u a r t z Z | a p a t i t e "7 o r t h o c l a s e sphene s a n i d i n e l a u m o n t i t e a d u l a r i a d i c k i t e b i o t i t e i l l i t e 3 h o r n b l e n d e a l u n i t e b a s a l t i c h o r n b l e n d e a c t i n b l i t e c l i n o p y r o x e n e z o i s i t e i r o n o x i d e g l a s s *f h e m a t i t e I m a g n e t i t e p y r i t e 3 c h l o r i t e e p i d o t e *7 c a r b o n a t e TOODOGGONE RIVER  NTS: 94E A. HEADING INFORMATION Sample Number: |0(o(o Rock Name: <^VA.O.VH- \r\-»o*»TUb*» vVc Geological Unit: (0 O *r\ »r\ec«. 3L~«%+v»w**w«.^ B. MAJOR ELEMENTS Si02 Ti02 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 \SS8 5-U3 o.fo 0.18 2U> 381 3.«.a 0 2 | 00^ 0.11 C. TRACE ELEMENTS Ni Cr V Sr Rb Ba Zr Nb Th Cu Au Ag a. 2.3 21a TI 23S© O 13 (p s l o D. PETROGRAPHIC DESCRIPTIONS Eruptive Type/Mode of Occurrence ash flow agglomerate b r e c c i a dyke flow b r e c c i a nuee ardente p y r o c l a s t i c Textur e/Structures amygdular aphanitic banded brecciated coarse d e v i t r i f i e d e u t a x i t i c embayed phenocr \/equigranular fiamme f i n e flow banded f o l i a t e d State of Preservation yfresh a l t e r e d 1. s l i g h t l y 2. moderately 3. extensively ^ s i l l stoct t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c welded t u f f glomerporphyritic graded bedding g r a n i t i c graphic • h y p i d iomo r phic massive m i c r o c r y s t a l l i n e ysts mineral pseudomorphs p o r p h y r i t i c pumiceous veined t r a c h y t i c v e s i c u l a r Type o f A l t e r a t i o n a r g i l l i c c a r b o n a t i c c h l o r i t i c d e u t e r i c h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — * • s e r i c i t e p l a g i o c l a s e — • c h l o r i t e p l a g i o c l a s e — • e p i d o t e +. s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — * c l a y s + a l u n i t e p l a g i o c l a s e — » q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — ^ T s e r c i t e h o r n b l e n d e — • c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — • opaques h o r n b l e n d e — » p r e h n i t e h o r n b l e n d e • q u a r t z b i o t i t e — » e p i d o t e + c h l o r i t e b i o t i t e —» c h l o r i t e c l i nopyroxene—» c h l o r i t e + opaques c l i n o p y r o x e n e — * opaques p r e h n i t i c p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : — % g r o u n d m a s s : — % 57 p l a g i o c l a s e An c o n t : / V n ^ k q u a r t z o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e h e m a t i t e m a g n e t i t e p y r i t e c h l o r i t e e p i d o t e c a r b o n a t e % 2- s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i e k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: lOUT Rock Name: V\pv*V>\e>ncXe. av\<JU*tVc< Geological Unit: l«-J- " | o o d o ^ c M & . ve>lcar\»c$ B. MAJOR ELEMENTS S102 Ti02 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 »t»7T 2-83 213 3.1-1 2-84 o.e>s o-31 C. TRACE ELEMENTS Ni Cr V Sr Rb Ba Zr Nb Th Cu Au Ag lo 2. 44| f j i i 7 5 lo PETROGRAPHIC DESCRIPTIONS Eruptive Type/Mode of Occurrence ash flow agglomerate b r e c c i a dyke • f low^/breccia nuee ardente p y r o c l a s t i c Texture/Structures amygdular aph a n i t i c banded brecciated coarse d e v i t r i f i e d e u t a x i t i c embayed phenocrysts equ igranular fiamme f i n e • flow banded f o l i a t e d s i l l stock t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c welded t u f f yr-glomerporphyritic graded bedding g r a n i t i c graphic hypidiomorphic massive m i c r o c r y s t a l l i n e v/mineral pseudomorphs p o r p h y r i t i c ~ pumiceous veined t r a c h y t i c v " v e s i c u l a r State of Preservation f r e s h y/'altered 1. s l i g h t l y 1/2. moderately 3. extensively Type o f A l t e r a t i o n a r g i l l i c p r e h n i t i c c a r b o n a t i c y/ p r o p y l i t i c \/ c h l o r i t i c s e r i c i t i c d e u t e r i c s i l i c i f i c a t i o n \/ h y d r o t h e r m a l z e o l i t i c l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — • s e r i c i t e \ / p l a g i o c l a s e — » c h l o r i t e • p l a g i o c l a s e — > e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — » q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e h o r n b l e n d e — • c h l o r i t e + opaques hornb lende—» e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — • opaques h o r n b l e n d e — • p r e h n i t e h o r n b l e n d e — • q u a r t z b i o t i t e — » e p i d o t e + c h l o r i t e b i o t i t e —» c h l o r i t e c l i n o p y r o x e n e — • c h l o r i t e + opaques c l i n o p y r o x e n e — * opaques M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : 35 % g r o u n d m a s s : 6>S % 52. p l a g i o c l a s e An c o n t : 3 q u a r t z o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e I h e m a t i t e m a g n e t i t e p y r i t e 2^ c h l o r i t e l 3 e p i d o t e > c a r b o n a t e s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: B. MAJOR ELEMENTS S i 0 2 T i 0 2 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 o . S t , i ^ 8 ( » M X 0. (6 <3S 3 i f i <M8 i-3o C. TRACE ELEMENTS N i Cr V S r Rb Ba Z r Nb Th Cu Au Ag 7 0 IVI «S1 rx<# 11 IO IS 1 i t 13 D. PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w s i l l s t o c k t u f f a g g l o m e r a t e b r e c c i a d y k e t u f f b r e c c i a v e i n v o l c a n o c l a s t i c w e l d e d t u f f f l o w / b r e c c i a nuee a r d e n t e p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e d e v i t r i f l e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iamme f i n e f l o w banded f o l i a t e d \S p o r p h y r i t i c l / m i n e r a l pseudomorphs t r a c h y t i c • " v e s i c u l a r g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c hy p i d iomo r p h i c m a s s i v e m i c r o c r y s t a l l i n e pumiceous v e i n e d S t a t e o f P r e s e r v a t i o n f r e s h • a l t e r e d 1. s l i g h t l y 1/5. m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c p r e h n i t i c c a r bona t i c • p r o p y l i t i c c h l o r i t i c s e r i c i t i c d e u t e r i c s i l i c i f i c a t i o n y/* h y d r o t h e r m a l z e o l i t i c l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — • s e r i c i t e • p l a g i o c l a s e — r c h l o r i t e p l a g i o c l a s e — » e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — • q u a r t z p l a g i o c l a s e — » p o t a s s i u m f e l d s p a r • h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques • hornb lende—» e p i d o t e + c h l o r i t e + opaques  • h o r n b l e n d e —»opaques h o r n b l e n d e — • p r e h n i t e h o r n b l e n d e — * q u a r t z • b i o t i t e — » e p i d o t e + c h l o r i t e b i o t i t e — * c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques c l i nopyroxene—» opaques M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : % g r o u n d m a s s : k[ % % yo p l a g i o c l a s e An c o n t : NOT poft*v»i£ \ s e r i c i t e q u a r t z ^ . u u a p a t i t e o r t h o c l a s e sphene s a n i d i n e l a u m o n t i t e a d u l a r i a d i e k i t e | b i o t i t e i l l i t e 7 h o r n b l e n d e a l u n i t e b a s a l t i c h o r n b l e n d e a c t i n b l i t e c l i n o p y r o x e n e z o i s i t e i r o n o x i d e g l a s s "3 h e m a t i t e \y-A\x. - \ m a g n e t i t e p y r i t e £ c h l o r i t e 2,0 e p i d o t e c a r b o n a t e TOODOGGONE RIVER NTS: 94E A . HEADING INFORMATION B. MAJOR ELEMENTS S i 0 2 T i 0 2 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 5fcoo Ol»1 B.oS OM 3.1-1 I 11 o.3S C. TRACE ELEMENTS N i Cr V S r Rb Ba Zr Nb Th Cu Au Ag 0 o •31 4LS t3 10 3 '3 5 D. PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a g g l o m e r a t e b r e c c i a a s h f l o w s i l l s t o c k • t u f f d y k e t u f f b r e c c i a v e i n v o 1 c a n o c l a s t i c w e l d e d t u f f f l o w b r e c c i a nuee a r d e n t e • p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e ^ a p h a n i t i c banded b r e c c i a t e d c o a r s e d e v i t r i f i e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iamme f i n e f l o w banded f o l i a t e d ^ m i n e r a l pseudomorphs p o r p h y r i t i c • p u m i c e o u s v e i n e d t r a c h y t i c v e s i c u l a r S t a t e o f P r e s e r v a t i o n f r e s h s • a l t e r e d 1. s l i g h t l y >^2. m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c p r e h n i t i c c a r b o n a t i c • p r o p y l i t i c y / c h l o r i t i c s e r i c i t i c d e u t e r i c s i l i c i f i c a t i o n y h y d r o t h e r m a l z e o l i t i c l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — • s e r i c i t e • p l a g i o c l a s e — * c h l o r i t e • p l a g i o c l a s e — * e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e -p l a g i o c l a s e — * q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques • h o r n b l e n d e — » opaques h o r n b l e n d e — * p r e h n i t e h o r n b l e n d e — » q u a r t z b i o t i t e — » e p i d o t e + c h l o r i t e b i o t i t e — * c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques c l i nopyroxene—» opaques M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : — % g r o u n d m a s s : — % 5 4 fe p l a g i o c l a s e An c o n t : q u a r t z o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e h e m a t i t e m a g n e t i t e p y r i t e c h l o r i t e e p i d o t e c a r b o n a t e % 2 s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e \ $ g l a s s TOODOGGONE RIVER NTS: 94E HEADING INFORMATION Sample Number: \ \ QQ Rock Name: r>oV"v\\r>\e*\o\ft G.v\d*6 *Vo G e o l o g i c a l U n i t : [ Ar " T o o d o ^ o < s > C B. MAJOR ELEMENTS S i 0 2 T i 0 2 AL203 Fe203 5 S o FeO 6 j j MnO t>.IB MgO 2.5? CaO 1#H Na20 /V4 K20 P205 Oil C02 H20 TRACE ELEMENTS N i Cr V S r Rb Ba Z r Nb Th Cu Au Ag io 3 »bL a S o i « 4 o ss 8 XI '1 PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w a g g l o m e r a t e b r e c c i a d y k e • f l o w / b r e c c i a nuee a r d e n t e p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e d e v i t r i f i e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iarame f i n e | / f l o w banded f o l i a t e d S t a t e o f P r e s e r v a t i o n s i l l s t o c k t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e • m i n e r a l pseudomorphs y p o r p h y r i t i c pumiceous , \/ v e i n e d S l * * ^ t t r a c h y t i c v e s i c u l a r f r e s h • a l t e r e d 1. s l i g h t l y m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c • c a r b o n a t i c • c h l o r i t i c d e u t e r i c h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — • s e r i c i t e • p l a g i o c l a s e — * c h l o r i t e • p l a g i o c l a s e — » e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — » q u a r t z p l a g i o c l a s e — » p o t a s s i u m f e l d s p a r ^ h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques • h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — » opaques h o r n b l e n d e — * p r e h n i t e h o r n b l e n d e • q u a r t z b i o t i t e — * e p i d o t e + c h l o r i t e b i o t i t e — * c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques c l i n o p y r o x e n e — * opaques p r e h n i t i c • p r o p y l i t i c s e r i c i t i c • s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : 32> % g r o u n d m a s s : 6 % % 1 p l a g i o c l a s e An c o n t : q u a r t z o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e 2 h e m a t i t e 4 Y < U C m a g n e t i t e 2„ p y r i t e ti| c h l o r i t e g e p i d o t e 11 c a r b o n a t e % •+v«xfc- s e r i c i t e 4 y A U _ a p a t i t e sphene l a u m o n t i t e d i e k i t e i l l i t e a l u n i t e a c t i n d l i t e z o i s i t e g l a s s TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: \ \ \ o Rock Name: V\ o r r\V>\ tode, ef,\Vo Geological Unit: \ ^ T o o A o ^ ^ o^ e MD\«A»M6> B. MAJOR ELEMENTS Si02 Ti02 ©.se AL203 Fe203 FeO /•<Vfc> MnO o-it. MgO CaO Na20 2./y K20 * '7 P205 C02 0-7TI H20 204 TRACE ELEMENTS Ni Cr V Sr Rb Ba Zr Nb Th Cu Au Ag r 0 / U i t1Z 61 if So 51 1 \a 3 0 y< PETROGRAPHIC DESCRIPTIONS Eruptive Type/Mode of Occurrence ash flow agglomerate b r e c c i a ydyke y flow/breccia nuee ardente p y r o c l a s t i c Texture/Structures • amygdular aph a n i t i c banded brecciated coarse d e v i t r i f i e d e u t a x i t i c embayed phenocrysts equigranular f iamme f i n e flow banded f o l i a t e d s i l l stock t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c welded t u f f glomerporphyr i t i c graded bedding g r a n i t i c graphic hypidiomorphic massive m i c r o c r y s t a l l i n e y/mineral pseudomorphs p o r p h y r i t i c pumxceous veined t r a c h y t i c v e s i c u l a r State of Preservation f r e s h • ' a l t e r e d 1. s l i g h t l y • % . moderately 3. extensively Type o f A l t e r a t i o n a r g i l l i c • c a r b o n a t i c ^ c h l o r i t i c d e u t e r i c • h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — * • s e r i c i t e • " p l a g i o c l a s e — • c h l o r i t e \y p l a g i o c l a s e — • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c i a y s + a l u n i t e p l a g i o c l a s e — * q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r ^ h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — - ^ s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — » opaques h o r n b l e n d e — • p r e h n i t e h o r n b l e n d e — • q u a r t z b i o t i t e — * e p i d o t e + c h l o r i t e b i o t i t e — * c h l o r i t e c l i n o p y r o x e n e — • c h l o r i t e + opaques c l i n o p y r o x e n e — * opaques p r e h n i t i c p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : 2.^  % g r o u n d m a s s : 7/ % p l a g i o c l a s e An c o n t : q u a r t z o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e h e m a t i t e m a g n e t i t e ( p y r i t e lS c h l o r i t e 5" e p i d o t e lS" c a r b o n a t e Not s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: | \ I ^ O Rock Name: V\OYv\\>\e^ dU. atNcU-vVc* G e o l o g i c a l U n i t : W To B. MAJOR ELEMENTS S i 0 2 W>B4, T i 0 2 ©.3*, AL203 Fe203 FeO 3 ' 1 MnO O.IL MgO 3.ov CaO 3.8ft Na20 3. S3. K20 3.31 P205 C02 H20 3.oe C. TRACE ELEMENTS N i Cr V S r Rb Ba Zr Nb Th Cu Au Ag t o n i S l o S o 33 fe 10 D. PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w a g g l o m e r a t e b r e c c i a d y k e s i l l s t o c k t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c w e l d e d t u f f p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e d e v i t r i f i e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iamme f i n e f l o w banded f o l i a t e d • m i n e r a l pseudomorphs • p o r p h y r i t i c pumiceous v e i n e d t r a c h y t i c v e s i c u l a r g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c hyp i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e S t a t e o f P r e s e r v a t i o n f r e s h y / a l t e r e d 1. s l i g h t l y m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c c a r b o n a t i c V j c h l o r i t i c _ d e u t e r i c yShydrothermal l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — * s e r i c i t e • p l a g i o c l a s e — * c h l o r i t e IS p l a g i o c l a s e — » e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — • q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r • ' h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques ^ • h o r n b l e n d e — » e p i d o t e + c h l o r i t e + opaques • ' ' h o r n b l e n d e — » opaques h o r n b l e n d e — * p r e h n i t e h o r n b l e n d e — • q u a r t z b i o t i t e — * e p i d o t e + c h l o r i t e b i o t i t e — * c h l o r i t e c l i n o p y r o x e n e — • c h l o r i t e + opaques c l i nopyroxene—» opaques p r e h n i t i c • ' p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : % g r o u n d m a s s : 4>$* % % 50 p l a g i o c l a s e An c o n t : A \ p \ V i r - X 0 I s e r i c i t e 2- q u a r t z ^ a u _ a p a t i t e o r t h o c l a s e sphene s a n i d i n e l a u m o n t i t e a d u l a r i a d i e k i t e -b-«.U-biot i te i l l i t e 5 h o r n b l e n d e a l u n i t e b a s a l t i c h o r n b l e n d e a c t i n d l i t e c l i n o p y r o x e n e z o i s i t e i r o n o x i d e g l a s s j ( h e m a t i t e *• m a g n e t i t e -Iv p y r i t e »4 c h l o r i t e l"7 e p i d o t e ij c a r b o n a t e TOODOGGONE RIVER NTS: 94E HEADING INFORMATION Sample Number: Rock Name: VvoVv>.\o\tv\dvt, o . v > A t * > ^ C G e o l o g i c a l U n i t : \Ar ~T~6o A o f t ^ o . j £ , N/oVceorMC^ B. MAJOR ELEMENTS S102 T i 0 2 O Aft, AL203 Fe203 3 -Ml FeO MnO o.\8 MgO V 4 f CaO Na20 K20 3.»3 P205 C02 H20 o.o TRACE ELEMENTS N i Cr V S r Rb Ba Z r Nb Th Cu Au Ag it 2 o 1X1 »1t « r ^ 8 6& 1 Hx. // 5* J .o PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w a g g l o m e r a t e b r e c c i a d y k e y/~ f l o w / b r ec c i a nuee a r d e n t e p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e d e v i t r i f l e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iamme f i n e f l o w banded f o l i a t e d s i l l s t o c k t u f f t u f f b r e c c i a v e i n v o 1 c a n o c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e m i n e r a l pseudomorphs  • p o r p h y r i t i c " " " . pumiceous v e i n e d t r a c h y t i c v e s i c u l a r S t a t e o f P r e s e r v a t i o n f r e s h • ' a l t e r e d 1. s l i g h t l y m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c c a r b o n a t i c • c h l o r i t i c d e u t e r i c • h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — • s e r i c i t e • p l a g i o c l a s e — * c h l o r i t e • p l a g i o c l a s e — » e p i d o t e 4- s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — • q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r •\/ h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — * s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques • h o r n b l e n d e — » opaques h o r n b l e n d e — * p r e h n i t e h o r n b l e n d e — • q u a r t z b i o t i t e — » e p i d o t e + c h l o r i t e b i o t i t e —» c h l o r i t e c l inopyroxene—» c h l o r i t e + opaques c l i n o p y r o x e n e — • opaques M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : " ^ - ^ % g r o u n d m a s s : 1 ) % £>j p l a g i o c l a s e An c o n t : A ^ 0 -y q u a r t z o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e ij h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e 2, h e m a t i t e m a g n e t i t e p y r i t e X*j c h l o r i t e S e p i d o t e Z c a r b o n a t e p r e h n i t i c p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c % 2» s e r i c i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: Rock Name: \o»oV\V-e» V>or«\V>V«p>dl<, a^duv^C G e o l o g i c a l U n i t : \\ T o o d o ^ y M « , Vo\co.**t* B. MAJOR ELEMENTS S i 0 2 T i 0 2 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 fco.fe} o-SI 4 * 1 U l S-Hl 3- s .vy o./f. 0.05 i-8f TRACE ELEMENTS N i Cr V S r Rb Ba Z r Nb Th Cu Au Ag PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w a g g l o m e r a t e b r e c c i a d y k e \/ f l o w / b r e c c i a nuee a r d e n t e p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e d e v i t r i f i e d e u t a x i t i c embayed p h e n o c r y s t s equ i g r a n u l a r f iamme f i n e f l o w banded f o l i a t e d s i l l s t o c k t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e • m i n e r a l pseudomorphs  p o r p h y r i t i c ~ pumiceous v e i n e d t r a c h y t i c v e s i c u l a r S t a t e o f P r e s e r v a t i o n f r e s h • a l t e r e d 1. s l i g h t l y 1/2. m o d e r a t e l y 3 . e x t e n s i v e l y Type of A l t e r a t i o n a r g i l l i c carbonatic y/ c h l o r i t i c deuteric •y hydrothermal leached potassic Mineral A l t e r a t i o n s and Replacements p l a g i o c l a s e — • s e r i c i t e >y p l a g i o c l a s e — r c h l o r i t e \S p l a g i o c l a s e — » epidote + s e r i c i t e + carbonate 4- a l b i t e p l a g i o c l a s e — • cla y s + a l u n i t e p l a g i o c l a s e — • quartz p l a g i o c l a s e — • potassium feldspar ^ h e m a t i z e d p l a g i o c l a s e hematized potassium feldspar potassium feldspar—» s e r c i t e • hornblende^-* c h l o r i t e + opaques h o r n b l e n d e — ^ epidote + c h l o r i t e + opaques • hornblende — » opaques hornblende — * prehnite hornblende — • q u a r t z b i o t i t e — • epidote + c h l o r i t e \S b i o t i t e — » c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques c l i n o p y r o x e n e — * opaques p r e h n i t i c • p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t ion z e o l i t i c Mineral Assemblage % phenocrysts: ^ % groundmass: 4,3 % 57 2. p l a g i o c l a s e An cont: quartz orthoclase sanidine a d u l a r i a b i o t i t e hornblende b a s a l t i c hornblende clinopyroxene i r o n oxide hematite magnetite p y r i t e 2S* c h l o r i t e t l epidote carbonate 5" 3 -TV s e r i c i t e a p a t i t e sphene laumontite d i e k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e glass TOODOGGONE RIVER NTS: 94E A . HEADING INFORMATION Sample Number: Rock Name: V\ovwV&V i c t A e , e o r \ d t * v V e -G e o l o g i c a l U n i t : W T o o d O ^ o ^ t - \/o\ <-*vv\. u» B. MAJOR ELEMENTS S i 0 2 T i 0 2 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 3-41 3.6^ «y-73 V87 3.-IO 0-2.2. 0/3 o-7i-TRACE ELEMENTS N i Cr V S r Rb Ba Z r Nb Th Cu Au Ag 11 0 7L 3b //Vo V8 3o PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w a g g l o m e r a t e b r e c c i a d y k e • " f l o w y b r e c c i a nuee a r d e n t e p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded • b r e c c i a t e d c o a r s e d e v i t r i f i e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iamme f i n e • f l o w banded f o l i a t e d s i l l s t o c k t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e • m i n e r a l pseudomorphs l^ f r o r p h y r i t i c pumiceous v e i n e d t r a c h y t i c v e s i c u l a r S t a t e o f P r e s e r v a t i o n f r e s h • a l t e r e d 1. s l i g h t l y 1/2. m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c p r e h n i t i c c a r b o n a t i c • p r o p y l i t i c • c h l o r i t i c ^ s e r i c i t i c d e u t e r i c s i l i c i f i c a t i o n • h y d r o t h e r m a l z e o l i t i c l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s \Splagioclase—• s e r i c i t e i ^ p l a g i o c l a s e — » c n x o r i t e ^ p l a g i o c l a s e — » e p i d o t e + " s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — * q u a r t z p l a g i o c l a s e — * p o t a s s i u m f e l d s p a r • ' h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques ! • h o r n b l e n d e — » opaques h o r n b l e n d e — • p r e h n i t e h o r n b l e n d e — • q u a r t z b i o t i t e — * e p i d o t e + c h l o r i t e b i o t i t e — * c h l o r i t e c l i n o p y r o x e n e — • c h l o r i t e + opaques c l i n o p y r o x e n e — * opaques M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : ^® % g r o u n d m a s s : feX-% % 50 p l a g i o c l a s e An c o n t : 4 s e r i c i t e 3 q u a r t z JL^ a p a t i t e o r t h o c l a s e sphene s a n i d i n e l a u m o n t i t e a d u l a r i a d i e k i t e b i o t i t e i l l i t e h o r n b l e n d e a l u n i t e b a s a l t i c h o r n b l e n d e a c t i n b l i t e c l i n o p y r o x e n e z o i s i t e i r o n o x i d e g l a s s I h e m a t i t e m a g n e t i t e I 1 p y r i t e \4 c h l o r i t e ("1 e p i d o t e _2 c a r b o n a t e TOODOGGONE RIVER NTS: 94E A . HEADING INFORMATION Sample Number: \oio Rock Name: G e o l o g i c a l U n i t : 2 -3 B. MAJOR ELEMENTS S i 0 2 VI T l T i 0 2 o.BW AL203 Fe203 FeO MnO o.ir MgO 3 I U CaO s v Na20 K20 '»3 P205 6.XL C02 H20 4 V j C. TRACE ELEMENTS N i Cr V S r Rb Ba Zr Nb Th Cu Au Ag — — D. PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w a g g l o m e r a t e b r e c c i a s i l l s t o c k t u f f u^dyke t u f f b r e c c i a v e i n v o l c a n o c l a s t i c w e l d e d t u f f f l o w b r e c c i a nuee a r d e n t e p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c hyp i d iomo r p h i c m a s s i v e m i c r o c r y s t a l l i n e m i n e r a l pseudomorphs p o r p h y r i t i c pumiceous v e i n e d t r a c h y t i c v e s i c u l a r • a p h a n i t i c banded b r e c c i a t e d c o a r s e d e v i t r i f i e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iamme f i n e f l o w banded f o l i a t e d S t a t e o f P r e s e r v a t i o n Jrresh y/altered i ^ l . s l i g h t l y 2. m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c c a r b o n a t i c c h l o r i t i c y / ^ d e u t e r i c ? h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — • s e r i c i t e p l a g i o c l a s e — » c h l o r i t e p l a g i o c l a s e — • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — » c l a y s + a l u n i t e p l a g i o c l a s e — • q u a r t z p l a g i o c l a s e — — • p o t a s s i u m f e l d s p a r h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — * s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques hornb lende—»opaques h o r n b l e n d e — * p r e h n i t e h o r n b l e n d e — • q u a r t z b i o t i t e — » e p i d o t e + c h l o r i t e b i o t i t e — * c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques \y c l i nopyroxene—» opaques p r e h n i t i c y ^ p r o p y l l t i c ^ s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : It) % g r o u n d m a s s : (o\ p l a g i o c l a s e An c o n t : q u a r t z o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e |*j c l i n o p y r o x e n e \t i r o n o x i d e •\V h e m a t i t e 2. m a g n e t i t e p y r i t e (a c h l o r i t e e p i d o t e 8 c a r b o n a t e 50 s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s TOODOGGONE RIVER NTS: 94E A . HEADING INFORMATION Sample Number: lQ$3 Rock Name: I p v y t>*«v\i, o.v->dULVArC* G e o l o g i c a l U n i t : 2 ^ B. MAJOR ELEMENTS S i 0 2 T i 0 2 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 L\\\ IU.OJ 6 H S-DO a-86 2.71 /•33 o.lfi /•4f /•13 TRACE ELEMENTS N i Cr V S r Rb Ba Zr Nb Th Cu Au Ag — - — - — — — — - -D. PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w a g g l o m e r a t e b r e c c i a • ^ d v k e f l o w b r e c c i a nuee a r d e n t e p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e d e v i t r i f i e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iamme f i n e f l o w banded f o l i a t e d s i l l s t o c k t u f f t u f f b r e c c i a v e i n v o 1 c a n o c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c hyp i d iomo r p h i c m a s s i v e m i c r o c r y s t a l l i n e m i n e r a l pseudomorphs • " p o r p h y r i t i c pumlceous v e i n e d t r a c h y t i c v e s i c u l a r S t a t e o f P r e s e r v a t i o n \S f r e s h a l t e r e d 1. s l i g h t l y 2. m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c c a r b o n a t i c c h l o r i t i c d e u t e r i c h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — • s e r i c i t e p l a g i o c l a s e — * c h l o r i t e p l a g i o c l a s e — • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — • q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — * s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — • opaques h o r n b l e n d e — * p r e h n i t e h o r n b l e n d e • q u a r t z b i o t i t e — » e p i d o t e + c h l o r i t e b i o t i t e — * c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques c l i nopyroxene—» opaques p r e h n i t i c p r o p y l i t i c v / s e r i c i t i c bnmoy s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : — % g r o u n d m a s s : —-% *!> »8 s 3 l p l a g i o c l a s e An c o n t : q u a r t z o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e h e m a t i t e m a g n e t i t e p y r i t e c h l o r i t e e p i d o t e c a r b o n a t e % A ^ H S "Vv s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s TOODOGGONE RIVER NTS: 94E A . HEADING INFORMATION Sample Number: Rock Name: Dx»V>V«. Vt»rwfeU>**C Av\du^\<V<» G e o l o g i c a l U n i t : \\ ~\ Oodo&Ck \)o^fc*v\ttfc B. MAJOR ELEMENTS S102 T i 0 2 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 5 B . o 5 i * 3 o ^.»3 2 . - O U O . I B *.8o r i . 3 . M o. 1^  0.11 C. TRACE ELEMENTS N i Cr V S r Rb Ba Zr Nb Th Cu Au Ag — D. PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w a g g l o m e r a t e b r e c c i a d y k e t u f f b r e c c i a v e i n v o l c a n o c l a s t i c w e l d e d t u f f s i l l s t o c k t u f f nuee a r d e n t e p y r o c l a s t i c T e x t u r e / S t r u c t u r e s • f l o w banded sU^wt a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e d e v i t r i f i e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iamme f i n e L ^ m i n e r a l pseudomorphs ^ p o r p h y r i t i c g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c hyp i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e pumiceous v e i n e d f o l i a t e d t r a c h y t i c v e s i c u l a r S t a t e o f P r e s e r v a t i o n f r e s h a l t e r e d 1. s l i g h t l y • S . m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c c a r b o n a t i c c h l o r i t i c d e u t e r i c \Shydro t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — * s e r i c i t e • " ' p l a g i o c l a s e — * c h l o r i t e • p l a g i o c l a s e — » e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e ——+ c l a y s + a l u n i t e p l a g i o c l a s e — • q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e i/" h o r n b l e n d e — * c h l o r i t e + opaques • hornb lende—» e p i d o t e + c h l o r i t e + opaques • h o r n b l e n d e — » opaques h o r n b l e n d e • p r e h n i t e h o r n b l e n d e • q u a r t z b i o t i t e — * e p i d o t e + c h l o r i t e b i o t i t e — k c h l o r i t e c l inopyroxene—» c h l o r i t e + opaques c l i nopyroxene—» opaques p r e h n i t i c t X p r o p y l i t i c • s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : "2-^  % g r o u n d m a s s : ^ j % 3 3 3. 3 5 p l a g i o c l a s e An c o n t : q u a r t z ?©<ti%v£ o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e h e m a t i t e m a g n e t i t e p y r i t e c h l o r i t e e p i d o t e c a r b o n a t e s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s TOODOGGONE RIVER NTS: 94 E A . HEADING INFORMATION Sample Number: H i ^ Rock Name: cp» cA fc*-h C- ftvsdU>tVc G e o l o g i c a l U n i t : \% " T " b o < X ~ * t > >io\<A B. MAJOR ELEMENTS S i 0 2 T i 0 2 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 60-81 t-70 ••If M l 3.7/ 184 o.ai o.of C. TRACE ELEMENTS N i Cr V S r Rb Ba Z r Nb Th Cu Au Ag O 0 1 0 /of 'Wo 3 7 ; IL i t 10 ' 7 PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w a g g l o m e r a t e b r e c c i a d y k e f l o w b r e c c i a nuee a r d e n t e p y r o c l a s t i c I t p i c U i f t J T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e d e v i t r i f i e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iamme • f i n e f l o w banded f o l i a t e d s i l l s t o c k t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c \ ^ g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e m i n e r a l pseudomorphs p o r p h y r i t i c pumiceous v e i n e d t r a c h y t i c v e s i c u l a r S t a t e o f P r e s e r v a t i o n f r e s h ^ f a l t e r e d 1. s l i g h t l y 2. m o d e r a t e l y Vo*. e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c Scarbonatic y/ c n i o r i t i c d e u t e r i c ^y h y d r o t h e r m a l l e a c h e d p o t a s s i c p r e h n i t i c p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — * s e r i c i t e ^y p l a g i o c l a s e — • c h l o r i t e \typLag±ocLase — » e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — * q u a r t z p l a g i o c l a s e —•* p o t a s s i u m f e l d s p a r ^y h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e • h o r n b l e n d e — * c h l o r i t e + opaques hornb lende—» e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — » opaques h o r n b l e n d e — » p r e h n i t e h o r n b l e n d e — * q u a r t z b i o t i t e ^ - * e p i d o t e + c h l o r i t e b i o t i t e — » c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques c l i nopyroxene—» opaques M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : % g r o u n d m a s s : % S3 5* p l a g i o c l a s e An c o n t : q u a r t z o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e (ff h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e h e m a t i t e m a g n e t i t e p y r i t e c h l o r i t e \ *>) e p i d o t e "J c a r b o n a t e Nor. s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i e k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s S p e c i a l Note For Sample 1129 - E p i c l a s t i c A n d e s i t e T h i s sample showed s i g n s o f e x t e n s i v e w e a t h e r i n g , and thus may not be a r e p r e s e n t a t i v e sample o f t h i s u n i t . TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: Rock Name: b\e.o.cV>e.d. av \oW>» \4* G e o l o g i c a l U n i t : tu\V> T o o A o O j O y * V < A « A B. MAJOR ELEMENTS S i 0 2 T i 0 2 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 Ofcfc Id.io 0.0 04.0 ©•Co 118 2. IB 6*1 0.0 2 o.&o SVo C. TRACE ELEMENTS N i C r V S r Rb Ba Zr Nb " Th Cu Au Ag 2- O L I 8&6 >S 6o 18 b /o PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w a g g l o m e r a t e b r e c c i a d y k e f l o w b r e c c i a nuee a r d e n t e V / ^ p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded \S b r e c c i a t e d c o a r s e d e v i t r i f i e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iamme f i n e f l o w banded f o l i a t e d s i l l s t o c k t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e • m i n e r a l pseudomorphs p o r p h y r i t i c pumiceous t ^ v e i n e d t r a c h y t i c v e s i c u l a r S t a t e o f P r e s e r v a t i o n f r e s h a l t e r e d 1. s l i g h t l y 2. m o d e r a t e l y e x t e n s i v e l y 276 Type o f A l t e r a t i o n y/^  a r g i l l i c p r e h n i t i c c a r b o n a t i c p r o p y l i t i c c h l o r i t i c s e r i c i t i c v d e u t e r i c • s i l i c i f i c a t i o n ( »\«^Vfc-J - S '*vlev\ W h y d r o t h e r m a l z e o l i t i c ^ l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — * s e r i c i t e p l a g i o c l a s e — * c h l o r i t e p l a g i o c l a s e — • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e ySplagioclase — » c l a y s + a l u n i t e  • p l a g i o c l a s e — * q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — ^ e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — » opaques h o r n b l e n d e — • p r e h n i t e h o r n b l e n d e q u a r t z b i o t i t e — * e p i d o t e + c h l o r i t e b i o t i t e — * c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques c l i n o p y r o x e n e — * opaques M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : —" % g r o u n d m a s s : —-% 3 p l a g i o c l a s e An c o n t : NOT. \q q u a r t z <f»04«»ai.€ o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e 2, i r o n o x i d e h e m a t i t e m a g n e t i t e %, p y r i t e c h l o r i t e e p i d o t e 1— c a r b o n a t e s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i c k i t e } K ^ l m i ^ i l l i t e ; a l u n i t e a c t i n d l i t e z o l s i t e g l a s s TOODOGGONE RIVER NTS: 94E 277 HEADING INFORMATION Sample Number: l O ^ O Rock Name: c > Hpt»\. 0.«^ dU>»< G e o l o g i c a l U n i t : l*A<C MAJOR ELEMENTS S102 T i 0 2 AL203 Fe203 FeO o.3Y MnO MgO 2-43 CaO Na20 i.2.6 K20 P205 ©.if C02 o.r© H20 O.UJ TRACE ELEMENTS N i Cr V S r Rb Ba Z r Nb Th Cu Au Ag & 1 3 MS n 7 2 l O O 0 O /2- 6 1 H3S * 7 PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w a g g l o m e r a t e b r e c c i a d y k e f l o w b r e c c i a nuee a r d e n t e p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c • banded ^ • b r e c c i a t e d c o a r s e d e v i t r i f i e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iamme f i n e f l o w banded f o l i a t e d s i l l s t o c k t u f f t u f f b r e c c i a • v e i n v o l c a n o c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e ^ m i n e r a l pseudomorphs p o r p h y r i t i c pumiceous \y v e i n e d t r a c h y t i c v e s i c u l a r S t a t e o f P r e s e r v a t i o n f r e s h ^ a l t e r e d 1. s l i g h t l y 2. m o d e r a t e l y e x t e n s i v e l y Type of A l t e r a t i o n a r g i l l i c carbonatic c h l o r i t i c deuteric \ / hydrothermal leached potassic Mineral A l t e r a t i o n s and Replacements \f p l a g i o c l a s e — * s e r i c i t e p l a g i o c l a s e — * c h l o r i t e p l a g i o c l a s e — • epidote + s e r i c i t e + carbonate + a l b i t e p l a g i o c l a s e — * cla y s + a l u n i t e p l a g i o c l a s e — » quartz p l a g i o c l a s e — * potassium feldspar hematized p l a g i o c l a s e hematized potassium feldspar potassium feldspar—» s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — * epidote + c h l o r i t e + opaques hornblende — * opaques hornblende — » prehnite y^Tiornblende — > quartz biotite—» epidote + c h l o r i t e b i o t i t e — » c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques c l i n o p y r o x e n e — * opaques Mineral Assemblage % phenocrysts: ~ % groundmass:—-% \ l» p l a g i o c l a s e An cont: quartz orthoclase sanidine a d u l a r i a b i o t i t e | hornblende b a s a l t i c hornblende clinopyroxene V i r o n oxide jy hematite magnetite t£ p y r i t e c h l o r i t e epidote carbonate p r e h n i t i c p r o p y l i t i c \Ssericitic  • s i l l c i f i c a t i o n z e o l i t i c Nor P»K » % y s e r i c i t e a p a t i t e sphene laumontite d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e glass T O O D O G G O N E R I V E R N T S : 94E HEADING INFORMATION Sample Number: \O02-Rock Name: «,v\» c*lJx<.dL c ^ e U / a . G e o l o g i c a l U n i t : \<v«» " T b o d o ^ o ^ c B. MAJOR ELEMENTS S i 0 2 T i 0 2 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 0-88 n.oi im p-u »-3^ ©.12 O.Of 2.10 TRACE ELEMENTS N i Cr V S r Rb Ba Z r Nb Th Cu Au Ag % O 1 s 3V*0 0 *3 0 1 h o S\3 PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w a g g l o m e r a t e b r e c c i a d y k e f l o w b r e c c i a nuee a r d e n t e p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c • banded *s b r e c c i a t e d c o a r s e d e v i t r i f i e d e u t a x i t i c embayed p h e n o c r y s t s equ i g r a n u l a r f iamme f i n e f l o w banded f o l i a t e d s i l l s t o c k t u f f t u f f b r e c c i a v e i n vo 1 cano c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e ! • m i n e r a l pseudomorphs p o r p h y r i t i c pumiceous • " v e i n e d t r a c h y t i c v e s i c u l a r S t a t e o f P r e s e r v a t i o n ,£resh a l t e r e d 1. s l i g h t l y 2. m o d e r a t e l y \/^3. e x t e n s i v e l y TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: Rock Name: G e o l o g i c a l U n i t : B. MAJOR ELEMENTS S i 0 2 80.VS T i 0 2 AL203 Fe203 3 Z | FeO M O MnO 018 MgO CaO 1 So Na20 o . o i K20 IK P205 0 \ t C02 INI H20 <>or C. TRACE ELEMENTS N i Cr V S r Rb Ba Z r Nb Th Cu Au Ag — — — — — — —~ — — D. PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w a g g l o m e r a t e b r e c c i a s i l l s t o c k t u f f d y k e t u f f b r e c c i a • ' v e i n f l o w b r e c c i a nuee a r d e n t e p y r o c l a s t i c v o l c a n o c l a s t i c w e l d e d t u f f T e x t u r e/S t r u c t u r e s a m y g d u l a r a p h a n i t i c • ' banded g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c hyp i d iomo r p h i c m a s s i v e m i c r o c r y s t a l l i n e m i n e r a l pseudomorphs p o r p h y r i t i c pumiceous • b r e c c i a t e d c o a r s e d e v i t r i f l e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iamme f i n e f l o w banded f o l i a t e d t ^ V e i n e d t r a c h y t i c v e s i c u l a r S t a t e o f P r e s e r v a t i o n f r e s h • a l t e r e d 1. s l i g h t l y 2. m o d e r a t e l y v ^ . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c c a r b o n a t i c c h l o r i t i c d e u t e r i c h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — • s e r i c i t e p l a g i o c l a s e — » c h l o r i t e p l a g i o c l a s e — • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — * c l a y s + a l u n i t e \Splagioclase -—»quartz p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques hornb lende—» e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — • opaques h o r n b l e n d e — * p r e h n i t e v f h o m b l e n d e > q u a r t z b i o t i t e — * e p i d o t e + c h l o r i t e b i o t i t e —» c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques c l i n o p y r o x e n e — ^ opaques p r e h n i t i c p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : ~" % g r o u n d m a s s : — % 3 p l a g i o c l a s e An c o n t : q u a r t z o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e ^ t i r o n o x i d e * h e m a t i t e t, m a g n e t i t e 3 p y r i t e c h l o r i t e e p i d o t e I c a r b o n a t e % NOT P0M»t6ue I s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s Type o f A l t e r a t i o n a r g i l l i c c a r b o n a t i c c h l o r i t i c d e u t e r i c h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — • s e r i c i t e p l a g i o c l a s e — * c h l o r i t e p l a g i o c l a s e — » e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — * c l a y s + a l u n i t e • p l a g i o c l a s e — » q u a r t z p l a g i o c l a s e — » p o t a s s i u m f e l d s p a r h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — * s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — » opaques h o r n b l e n d e — » p r e h n i t e • h o r n b l e n d e —•» q u a r t z b i o t i t e — * e p i d o t e + c h l o r i t e b i o t i t e —» c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques c l i nopyroxene—» opaques p r e h n i t i c p r o p y l i t i c s e r i c i t i c • s i l l c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : —-% g r o u n d m a s s : _ % 10 I I p l a g i o c l a s e An c o n t : tfoT q u a r t z Poi&rgkC o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e h e m a t i t e m a g n e t i t e p y r i t e c h l o r i t e e p i d o t e c a r b o n a t e % 4v s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s TOODOGGONE RIVER NTS: 94E A . HEADING INFORMATION Sample Number: )\\3 Rock Name: Yvovw\>\t^ cLt A©.c*Vc> G e o l o g i c a l U n i t : \ ^ f o o A o ^ — e , V » W * * J w . B. MAJOR ELEMENTS S i 0 2 T i 0 2 O.MID AL203 Fe203 Z.»2 FeO 2.o| MnO 0.18 MgO Hi CaO 24S Na20 f ' 8 K20 ••HI P205 o.»l C02 H20 C. TRACE ELEMENTS N i Cr V S r Rb Ba Z r Nb Th Cu Au Ag 7 1 *>» a so H 2 r IO /•O PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e V a s h f l o w a g g l o m e r a t e b r e c c i a d y k e f l o w b r e c c i a • " n u e e a r d e n t e  • f r y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e ydevitrified \s e u t a x i t i c  i^embayed p h e n o c r y s t s equ i g r a n u l a r • f iamme f i n e f l o w banded f o l i a t e d s i l l s t o c k t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e K m i n e r a l pseudomorphs p o r p h y r i t i c pumiceous v e i n e d t r a c h y t i c • " V e s i c u l a r S t a t e o f P r e s e r v a t i o n f r e s h * • a l t e r e d V l . s l i g h t l y 2. m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c c a r b o n a t i c V ^ c h l o r i t i c ^ a e u t e r i c ; h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s • p l a g i o c l a s e — » s e r i c i t e  ^ p l a g i o c l a s e — » c h l o r i t e p l a g i o c l a s e — • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — * c l a y s + a l u n i t e p l a g i o c l a s e — • q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r l ^ h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — * s e r c i t e \S h o r n b l e n d e — • c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — » opaques h o r n b l e n d e — • p r e h n i t e h o r n b l e n d e • q u a r t z b i o t i t e — » e p i d o t e + c h l o r i t e b i o t i t e —» c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques c l i nopyroxene—» opaques p r e h n i t i c p r o p y l i t i c W ^ s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : — % g r o u n d m a s s : —-p l a g i o c l a s e An c o n t : Z2» q u a r t z o r t h o c l a s e 5 s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e 5" b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e 2. h e m a t i t e 3 m a g n e t i t e p y r i t e % c h l o r i t e e p i d o t e •fV c a r b o n a t e A n 3» % [ s e r i c i t e f r a p a t i t e ifY sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e 3^ g l a s s TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: \0%O Rock Name: V or K\o\ev\de d«-cv-V^ G e o l o g i c a l U n i t : \ *\ ~Too<*0^ ay> \jo\c*»v» B. MAJOR ELEMENTS S i 0 2 T102 ©•41 AL203 Fe203 2.87 FeO 2-321 MnO o.iei MgO 3.or CaO 2$7| Na20 v.si K20 P205 D.lC C02 0.0$ H20 0.37 TRACE ELEMENTS N i Cr V S r Rb Ba Zr Nb Th Cu Au Ag H O I0< 552. I V O 2-V 7 r 0.8 D. PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e y / a s h f l o w a g g l o m e r a t e b r e c c i a d y k e f l o w b r e c c i a • n u e e a r d e n t e • p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e • d e v i t r i f i e d t ^ e u t a x i t i c 1^embayed p h e n o c r y s t s e q u a g r a n u l a r (•diamine f i n e • f l o w banded f o l i a t e d S t a t e o f P r e s e r v a t i o n s i l l s t o c k t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e m i n e r a l pseudomorphs p o r p h y r i t i c ' p u m i c e o u s v e i n e d t r a c h y t i c v e s i c u l a r f r e s h . • a l t e r e d * ^ 1 . s l i g h t l y 2. m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c c a r b o n a t i c c h L o r i t i c d e u t e r i c h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s • ' ' p l a g i o c l a s e • s e r i c i t e •^ p l a g i o c l a s e — * c h l o r i t e p l a g i o c l a s e — • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — • q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e • ^ h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — * opaques h o r n b l e n d e — * p r e h n i t e h o r n b l e n d e — » q u a r t z b i o t i t e — » e p i d o t e + c h l o r i t e b i o t i t e — * c h l o r i t e c l i n o p y r o x e n e > c h l o r i t e + opaques c l i n o p y r o x e n e — * opaques p r e h n i t i c p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t i o n • ' " z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : —-% g r o u n d m a s s : % l 4 p l a g i o c l a s e An c o n t : »S q u a r t z o r t h o c l a s e Q s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e ^ b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e I h e m a t i t e r m a g n e t i t e ' t. p y r i t e y c h l o r i t e e p i d o t e ' c a r b o n a t e % Aaw 2. s e r i c i t e <fr a p a t i t e sphene I l a u m o n t i t e d i e k i t e i l l i t e a l u n i t e a c t i n o l i t e z o i s i t e ijf g l a s s TOODOGGONE RIVER NTS: 94E A . HEADING INFORMATION Sample Number: Rock Name: V\ ovw\o \ e-v\A & d,*.cvVc» G e o l o g i c a l U n i t : \ *\ \ OO<AO^O/M& V f o V c a v M U B. MAJOR ELEMENTS S102 T i 0 2 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 O-Mt W 4 S 1-11 016 353 i n a 0.1$ / • / ? TRACE ELEMENTS N i Cr V S r Rb Ba Z r Nb Th Cu Au Ag 3 X »&2 *J*7 O h (o PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e • a s h f l o w a g g l o m e r a t e b r e c c i a d y k e f l o w b r e c c i a U^nuee a r d e n t e t ^ p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e V ^ d e v i t r i f l e d e u t a x i t i c tX 'embayed p h e n o c r y s t s equ i g r a n u l a r f iamme f i n e f l o w banded f o l i a t e d s i l l s t o c k t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e u - " m i n e r a l pseudomorphs u4 o r p h y r i t i c pumiceous v e i n e d t r a c h y t i c v e s i c u l a r S t a t e o f P r e s e r v a t i o n f r e s h U n a l t e r e d • l . s l i g h t l y 2. m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c c a r b o n a t i c \S c h l o r i t i c ^ • d e u t e r i c 1 h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s • p l a g i o c l a s e — • s e r i c i t e • ' p l a g i o c l a s e — * c h l o r i t e p l a g i o c l a s e — • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — * c l a y s + a l u n i t e p l a g i o c l a s e — » q u a r t z p l a g i o c l a s e — » p o t a s s i u m f e l d s p a r • h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m F e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e • " h o r n b l e n d e — * c h l o r i t e + opaques • " h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — » opaques h o r n b l e n d e — » p r e h n i t e h o r n b l e n d e • q u a r t z b i o t i t e — » e p i d o t e + c h l o r i t e b i o t i t e — » c h l o r i t e c l inopyroxene—» c h l o r i t e + opaques c l i nopyroxene—» opaques p r e h n i t I c p r o p y l i t i c • ^ s e r i c i t i c s i l i c i f I c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : " % g r o u n d m a s s : —-% 32. p l a g i o c l a s e An c o n t : l i y q u a r t z o r t h o c l a s e S* s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e h e m a t i t e m a g n e t i t e p y r i t e %• c h l o r i t e e p i d o t e \ c a r b o n a t e 2. 2. % A«V^< ^ s e r i c i t e 1{V a p a t i t e j^. sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e 35 g l a s s TOODOGGONE RIVER NTS: 94E A . HEADING INFORMATION Sample Number: \\\o^» Rock Name: Woyw\>\e»Ae t G e o l o g i c a l U n i t : \ f c T f t odo^o^t , \Je»\uo.vs\U5 B. MAJOR ELEMENTS S i 0 2 T102 0-32. AL203 Fe203 FeO MnO A.IB MgO CaO 7.SO Na20 3-3* K20 3. II P205 o . l C C02 H20 TRACE ELEMENTS N i Cr V S r Rb Ba Zr Nb Th Cu Au Ag <\ J. tie <6W 31 l»8o 60 1 3 * tl T M PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e • " a s h f l o w a g g l o m e r a t e b r e c c i a d y k e f l o w b r e c c i a nuee a r d e n t e t^Jpyro c l a s t i c T e x t u r e/S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e u ^ d e v i t r i f i e d L ^ e u t a x i t i c •^embayed p h e n o c r y s t s e q u i g r a n u l a r • " f i a m m e f i n e f l o w banded f o l i a t e d s i l l s t o c k t u f f t u f f b r e c c i a v e i n v o 1 c a n o c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e ^ • m i n e r a l pseudomorphs p o r p h y r i t i c • " pumiceous v e i n e d t r a c h y t i c v e s i c u l a r S t a t e o f P r e s e r v a t i o n f r e s h a l t e r e d V I . s l i g h t l y 2. m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c c a r b o n a t i c • " c h l o r i t i c  • d e u t e r i c . h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s • p l a g i o c l a s e — * • s e r i c i t e • p l a g i o c l a s e — » c h l o r i t e p l a g i o c l a s e — • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — * c l a y s + a l u n i t e p l a g i o c l a s e — • q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r • h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e %y h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — » opaques h o r n b l e n d e — » p r e h n i t e h o r n b l e n d e — » q u a r t z b i o t i t e — * e p i d o t e + c h l o r i t e b i o t i t e —» c h l o r i t e c l i nopyroxene—» c h l o r i t e + opaques c l i n o p y r o x e n e — * opaques p r e h n i t i c p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t i o n z e o l l t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : % g r o u n d m a s s : % Xl \S <P H 3 I p l a g i o c l a s e An c o n t : NtfT" q u a r t z ?0&iftu£ o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e h e m a t i t e m a g n e t i t e p y r i t e c h l o r i t e e p i d o t e c a r b o n a t e % • s e r i c i t e -|y a p a t i t e sphene l a u m o n t i t e d i e k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: IW*1"^ Rock Name: V \ovvvVAevNo \ e . dl».c-vVe» G e o l o g i c a l U n i t : \ <\ - f o o d O ^ o ^ f r V « > \ C ^ » U B. MAJOR ELEMENTS S i 0 2 T i 0 2 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 0>lo\ 4**o I b 3 o.ai l-SV 0.08 O-So C. TRACE ELEMENTS N i Cr V ST Rb Ba Zr Nb Th Cu Au Ag lo H 151 5 3 IXOO r a? D. PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e • a s h f l o w a g g l o m e r a t e b r e c c i a d y k e f l o w b r e c c i a • n u e e a r d e n t e • p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e • ' d e v i t r i f i e d • ' e u t a x i t i c LXfembayed p h e n o c r y s t s e q u i g r a n u l a r f iamme f i n e i n f l o w banded f o l i a t e d S t a t e o f P r e s e r v a t i o n s i l l s t o c k t u f f t u f f b r e c c i a v e i n vo1cano c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e m i n e r a l pseudomorphs p o r p h y r i t i c pumlceous v e i n e d t r a c h y t i c v e s i c u l a r f r e s h • ' a l t e r e d s l i g h t l y 2. m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c c a r b o n a t i c \S c h l o r i t i c ^ ^ • d e u t e r i c . h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s • p l a g i o c l a s e — • s e r i c i t e y ^ p x a g i o c x a s e — » c m o r i t e p l a g i o c l a s e — • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — • q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r ^ h e m a t i z e d p l a g i o c l a s e n e m a c i z e a p o c a s s i i l m f e l d s p a r p o t a s s i u m f e l d s p a r — * s e r c l t e v/^hornb lende—» c h l o r i t e + opaques hornb lende—» e p i d o t e + c h l o r i t e + opaques • ^ h o r n b l e n d e — * o p a q u e s h o r n b l e n d e — * p r e h n i t e h o r n b l e n d e — • q u a r t z b i o t i t e — * e p i d o t e + c h l o r i t e b i o t i t e — \ c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques c l i nopyroxene—» opaques p r e h n i t i c p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : —-% g r o u n d m a s s : — % »4 3 p l a g i o c l a s e An c o n t : q u a r t z o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e h e m a t i t e m a g n e t i t e p y r i t e c h l o r i t e e p i d o t e c a r b o n a t e M o T % } s e r i c i t e 4 y a p a t i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e yfa g l a s s TOODOGGONE RIVER NTS: 94E A . HEADING INFORMATION Sample Number: Rock Name: ^ o ^ \ \ t - V»orVv.^\cr\dfc- dlft.cv\c G e o l o g i c a l U n i t : ^ O T o * d o ^ e M t v/oVcan»c4 B. MAJOR ELEMENTS S i 0 2 T102 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 t i . is 0.36 MS l.oft O.lfi »S1 a.oi 3.fei 2/»8 2.21 III C. TRACE ELEMENTS N i Cr V S r Rb Ba Z r Nb Th Cu Au Ag Z 0 83 3o3 53 »«3o t l O H 3 5 o,8 PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e • a s h f l o w a g g l o m e r a t e b r e c c i a d y k e f l o w b r e c c i a • n u e e a r d e n t e l ^ y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e u < i i e v i t r i f l e d e u t a x i t i c i ^ e m b a y e d p h e n o c r y s t s equ i g r a n u l a r f iamme f i n e f l o w banded f o l i a t e d s i l l s t o c k t u f f t u f f b r e c c i a v e i n v o 1 c a n o c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e m i n e r a l pseudomorphs u ^ p o r p h y r i t i c pumiceous v e i n e d t r a c h y t i c v e s i c u l a r S t a t e o f P r e s e r v a t i o n f r e s h • a l t e r e d • l . s l i g h t l y 2. m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c c a r b o n a t i c v ^ c h l o r i t i c j ^ d e u t e r i c 1 h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — » s e r i c i t e p l a g i o c l a s e — * c h l o r i t e p l a g i o c l a s e ——* e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — > q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r ±y h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m t e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e h o r n b l e n d e —-» c h l o r i t e 4- opaques h o r n b l e n d e ^ — * e p i d o t e + c h l o r i t e 4- opaques \y h o r n b l e n d e — » opaques h o r n b l e n d e — * p r e h n i t e h o r n b l e n d e — * q u a r t z b i o t i t e — » e p i d o t e 4- c h l o r i t e b i o t i t e — » c h l o r i t e c l i nopyroxene—» c h l o r i t e + opaques c l i n o p y r o x e n e — * opaques p r e h n i t i c p r o p y l i t i c \/ y s e r i c i t i c s i l i c i f i c a t i o n z e o l l t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : —' % g r o u n d m a s s : *~ % 15" p l a g i o c l a s e An c o n t : \Q q u a r t z o r t h o c l a s e B s a n i d i n e a d u l a r i a 5 b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e I h e m a t i t e 2. m a g n e t i t e . p y r i t e " c h l o r i t e + V e p i d o t e • f y c a r b o n a t e A n Ma- % "»> s e r i c i t e J^y a p a t i t e sphene l a u m o n t i t e d i e k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e ^ g l a s s TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: Rock Name: \o\o-Vi^ e Y\&v- wY>\cv\d t A*csAc Geological Unit: 2 0 "Tooc\oy^ o«#e. \ / o V B. MAJOR ELEMENTS Si02 Ti02 AL203 Fe203 S.&o FeO MnO MgO 3*1 CaO |.S«| Na20 K20 P205 C02 0 . 6 H20 TRACE ELEMENTS Ni Cr V Sr Rb Ba Zr Nb Th Cu Au Ag s 31 »01 i n W5" /Jto • b 3 2S /O /.o PETROGRAPHIC DESCRIPTIONS Eruptive Type/Mode of Occurrence y/ash flow agglomerate b r e c c i a dyke flow b r e c c i a y^nuee ardente V*»-pyroclastic Texture/Structures amygdular aphanitic banded brecciated coarse y ^ d e v i t r i f i e d e u t a x i t i c t^embayed phenocrysts equigranular f iamme f i n e flow banded f o l i a t e d s i l l stock t u f f t u f f breccia, v e i n v o l c a n o c l a s t i c welded t u f f glomerporphyritic graded bedding g r a n i t i c graphic hypidiomorphic massive m i c r o c r y s t a l l i n e mineral pseudomorphs ^ p o r p h y r i t i c • pumiceous veined t r a c h y t i c v e s i c u l a r State of Preservation f r e s h • a l t e r e d W^l. s l i g h t l y 2. moderately 3. extensively Type o f A l t e r a t i o n a r g i l l i c c a r b o n a t i c \ / c h l o r i t i c  ydeu te r i c^» h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — * s e r i c i t e •* p l a g i o c l a s e — » c h l o r i t e • p l a g i o c l a s e ——» e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — • q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r y h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m t e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e ^ h o r n b l e n d e — * c h l o r i t e + opaques ^ h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques y ^ h o r n b l e n d e — » opaques h o r n b l e n d e —-»prehn i te h o r n b l e n d e q u a r t z b i o t i t e — » e p i d o t e + c h l o r i t e \S b i o t i t e — » c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques c l i n o p y r o x e n e — * opaques p r e h n i t i c p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : % g r o u n d m a s s : % b 2. 3 p l a g i o c l a s e An c o n t : q u a r t z o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e h e m a t i t e m a g n e t i t e p y r i t e c h l o r i t e e p i d o t e c a r b o n a t e o - M o % I s e r i c i t e -Jy a p a t i t e J^y sphene l a u m o n t i t e d i e k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e */8 § l £ Lass TOODOGGONE RIVER 297 NTS: 94E A. HEADING INFORMATION Sample Number: Rock Name: V\ OV KVD\tv\dft dOvdVC' Geological Unit: \ ^  Too*0^op~* V O \ W K ' , W B. MAJOR ELEMENTS S i 0 2 T i 0 2 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 O.J& noi 2.10 o.n 3 4 S 0-«/3 2 - S l 432 0-21 o .o 0*80 C. TRACE ELEMENTS N i Cr V S r Rb Ba Z r Nb Th Cu Au Ag 1 X 51 <8<J 31 /fclo 6o 7 31- >3 y D. PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e • a s h f l o w a g g l o m e r a t e b r e c c i a d y k e f l o w b r e c c i a *-/nuee a r d e n t e • p y r o c l a s t i c T e x t u r e/S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e • ' d e v i t r i f i e d  ^ / e u t a x i t i c  [^•embayed ph*ehocrysts equ i g r a n u l a r • f i a m m e t i n e U ^ f l o w banded f o l i a t e d S t a t e o f P r e s e r v a t i o n s i l l s t o c k t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c hyp i d iomo r p h i c m a s s i v e m i c r o c r y s t a l l i n e w m i n e r a l pseudomorphs p o r p h y r i t i c • " p u m i c e o u s veined t r a c h y t i c v e s i c u l a r f r e s h • " a l t e r e d 1. s l i g h t l y \X2. m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c - c a r b o n a t i c V * c h l o r i t i c ^  V d e u t e r i c * h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — • s e r i c i t e y/' p l a g i o c l a s e — • c h l o r i t e p l a g i o c l a s e — • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — * c l a y s + a l u n i t e p l a g i o c l a s e — • q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r y/ h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r ^ - * s e r c i t e y / ^ h o r n b l e n d e — • c h l o r i t e + opaques h o r n b l e n d e — • e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — » opaques h o r n b l e n d e — • p r e h n i t e h o r n b l e n d e • q u a r t z b i o t i t e — * e p i d o t e + c h l o r i t e b i o t i t e — • c h l o r i t e c l i n o p y r o x e n e — • c h l o r i t e + opaques c l i nopyroxene—» opaques p r e h n i t i c p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : —' % g r o u n d m a s s : — % 8 3 t p l a g i o c l a s e An c o n t : A.* . _ q u a r t z " * * o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e h e m a t i t e m a g n e t i t e p y r i t e c h l o r i t e e p i d o t e c a r b o n a t e % I -V V 3* s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i e k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s TOODOGGONE RIVER NTS: 94E A . HEADING INFORMATION Sample Number: Rock Name: G e o l o g i c a l U n i t : % 1*. B. MAJOR ELEMENTS S i 0 2 T i 0 2 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 Ufc5 0.^0 0-/3 /•2l o.T) </©6 W9j 6 0 TRACE ELEMENTS N i Cr V S r Rb Ba Z r Nb Th Cu Au Ag 1 0 I f 17 * 0 2 3 5" 22. '!f f PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w a g g l o m e r a t e b r e c c i a w ^ d y k e f l o w b r e c c i a nuee a r d e n t e p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e d e v i t r i f i e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iamme f i n e f l o w banded f o l i a t e d S t a t e o f P r e s e r v a t i o n afresh s i l l s t o c k t u f f t u f f b r e c c i a v e i n vo 1 cano c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e m i n e r a l pseudomorphs V " ^ p o r p h y r i t i c pumiceous v e i n e d t r a c h y t i c v e s i c u l a r \ / a l t e r e d s l i g h t l y 2. m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c ^ c a r b o n a t i c Y ^ c h l o r i t i c d e u t e r i c h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — • s e r i c i t e • p l a g i o c l a s e — » c h l o r i t e V p l a g i o c l a s e e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — • q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r y * h e m a t i z e d p l a g i o c l a s e h e m a t i z e d p o t a s s i u m "Feldspar p o t a s s i u m f e l d s p a r — » s e r c i t e h o r n b l e n d e — ^ c h l o r i t e + opaques hornb lende—» e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — » opaques h o r n b l e n d e — • p r e h n i t e h o r n b l e n d e • q u a r t z b i o t i t e — * e p i d o t e + c h l o r i t e b i o t i t e — k c h l o r i t e c l inopyroxene—» c h l o r i t e + opaques c l i nopyroxene—» opaques M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : "3° % g r o u n d m a s s : "70 % \"L» p l a g i o c l a s e An c o n t : A * \ o * J 4 3 q u a r t z \\Q o r t h o c l a s e s a n i d i n e a d u l a r i a b i o t i t e & h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e % h e m a t i t e / m a g n e t i t e L p y r i t e 5 c h l o r i t e J^C e p i d o t e ^ c a r b o n a t e p r e h n i t i c p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c </ s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s TOODOGGONE RIVER NTS: 94E A . HEADING INFORMATION Sample Number: \0<\ \ Rock Name: VV.\^o\xVC G e o l o g i c a l U n i t : 2>2L B. MAJOR ELEMENTS S i 0 2 T i 0 2 AL203 Fe203 a.35 FeO |.*»3 MnO o.»7 MgO 3 bo CaO Na20 3.11 K20 V70 P205 6.26 C02 OO H20 o.-?1 C. TRACE ELEMENTS N i Cr V S r Rb Ba Zr Nb Th Cu Au Ag D. PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w s i l l s t o c k t u f f a g g l o m e r a t e b r e c c i a y/" d y k e t u f f b r e c c i a v e i n v o l c a n o c l a s t i c w e l d e d t u f f f l o w b r e c c i a nuee a r d e n t e p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e d e v i t r i f i e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iamme f i n e f l o w banded f o l i a t e d • p o r p h y r i t i c g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c hyp i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e m i n e r a l pseudomorphs pumiceous v e i n e d t r a c h y t i c v e s i c u l a r S t a t e o f P r e s e r v a t i o n f r e s h • a l t e r e d y 1. s l i g h t l y 2. m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c • ^ c a r b o n a t i c  • c h l o r i t i c d e u t e r i c h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s o l a g i o c l a s e — + s e r i c i t e • p l a g i o c l a s e — * c h l o r i t e p l a g i o c l a s e — • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — • q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r \yhematized p l a g i o c l a s e h e m a t i z e d p o t a s s i u m f e l d s p a r p o t a s s i u m f e l d s p a r — » s e r c i t e hornb lende—» c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — • opaques h o r n b l e n d e — • p r e h n i t e h o r n b l e n d e — • q u a r t z b i o t i t e — • e p i d o t e + c h l o r i t e b i o t i t e — » c h l o r i t e c l i n o p y r o x e n e - ^ c h l o r i t e + opaques c l i nopyroxene—» opaques p r e h n i t i c p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : % g r o u n d m a s s : % 85 p l a g i o c l a s e An c o n t : 55 q u a r t z 2Q o r t h o c l a s e s a n i d i n e a d u l a r l a b i o t i t e %. h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e h e m a t i t e m a g n e t i t e p y r i t e c h l o r i t e e p i d o t e \ c a r b o n a t e MoT PoiS. I f 3 \ s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i e k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s TOODOGGONE RIVER NTS: 94E HEADING INFORMATION Sample Number: U3>o Rock Name: "Vvo. cVy^Vfe G e o l o g i c a l U n i t : B. MAJOR ELEMENTS S i 0 2 T i 0 2 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 o.feo K 2 J 2 . 4 1 3.1* ».18 3»» 3-11 8.7g o.xo I'OU |.©V TRACE ELEMENTS N i Cr V S r Rb Ba Z r Nb Th Cu Au Ag It* IL I S * U o "IX 1480 IO W3 '3 4T D. PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w a g g l o m e r a t e b r e c c i a d y k e . V f l o w / b r e c c i a nuee a r d e n t e p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e d e v i t r i f i e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iamme f i n e f l o w banded f o l i a t e d s i l l s t o c k t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e • m i n e r a l pseudomorphs • p o r p h y r i t i c pumiceous v e i n e d t r a c h y t i c v e s i c u l a r S t a t e o f P r e s e r v a t i o n f r e s h • ^ a l t e r e d 1. s l i g h t l y t^Z. m o d e r a t e l y 3 . e x t e n s i v e l y 304 S p e c i a l Note F o r ^Sample 1130 - T r a c h y t e T h i s sample showed s i g n s o f e x t e n s i v e w e a t h e r i n g , and t h u s may n o t be a r e p r e s e n t a t i v e sample o f t h i s u n i t . Type o f A l t e r a t i o n a r g i l l i c U ^ c a r b o n a t i c • c h l o r i t i c d e u t e r i c • ^ h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s • ' ' p l a g i o c l a s e — • s e r i c i t e ^ • p l a g i o c l a s e — » c h l o r i t e t y p l a g i o c l a s e ——» e p i d o t e + " s e r l c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — » q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r • " h e m a t i z e d p l a g i o c l a s e ! • h e m a t i z e d p o t a s s i u m f e l d s p a r W ' p o t a s s i u m f e l d s p a r — » s e r c i t e • " h o r n b l e n d e — » c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — * opaques h o r n b l e n d e — • p r e h n i t e h o r n b l e n d e • q u a r t z b i o t i t e — * e p i d o t e + c h l o r i t e • ^ b i o t i t e — » c h l o r i t e c l i n o p y r o x e n e — • c h l o r i t e + opaques c l i nopyroxene—» opaques p r e h n i t i c p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : 3 ^ % g r o u n d m a s s : l»vj % 11 p l a g i o c l a s e An c o n t : q u a r t z o r t h o c l a s e *^ S* s a n i d i n e a d u l a r i a b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e h e m a t i t e m a g n e t i t e p y r i t e c h l o r i t e e p i d o t e c a r b o n a t e v $ s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n o l i t e z o i s i t e Lass TOODOGGONE RIVER NTS: 94E A . HEADING INFORMATION Sample Number: Rock Name: G e o l o g i c a l U n i t : B. MAJOR ELEMENTS S102 tO.«\3 T i 0 2 o . M I AL203 n.xi Fe203 FeO MnO MgO J 3D CaO O.St Na20 K20 1.03 P205 C02 O.oi H20 IS 1 C. TRACE ELEMENTS N i Cr V S r Rb Ba Z r Nb Th Cu Au Ag u 151 **7 l i f t i d M> V 3 3 5 PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w a g g l o m e r a t e b r e c c i a d y k e V^f l o w ^ r ecc i a nuee a r d e n t e p y r o c l a s t i c T e x t u r e/S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e d e v i t r i f i e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iamme f i n e • f l o w banded f o l i a t e d s i l l s t o c k t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e m i n e r a l pseudomorphs • p o r p h y r i t i c pumiceous v e i n e d t r a c h y t i c v e s i c u l a r S t a t e o f P r e s e r v a t i o n f r e s h . a l t e r e d 1. s l i g h t l y w2. m o d e r a t e l y 3 . e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c y/^carbonatic • c h l o r i t i c d e u t e r i c • " h y d r o t h e r m a l l e a c h e d p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s • ' p l a g i o c l a s e — • s e r i c i t e ^ p l a g i o c l a s e — » c h l o r i t e ^ . • p l a g i o c l a s e — » e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — • q u a r t z p l a g i o c l a s e — • p o t a s s i u m f e l d s p a r • h e m a t i z e d p l a g i o c l a s e  • h e m a t i z e d p o t a s s i u m f e l d s p a r  • p o t a s s i u m f e l d s p a r — * s e r c i t e  • h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — * opaques h o r n b l e n d e — • p r e h n i t e h o r n b l e n d e — • q u a r t z b i o t i t e — * e p i d o t e + c h l o r i t e • b i o t i t e — » c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques c l i nopyroxene—» opaques p r e h n i t i c p r o p y l i t i c s e r i c i t i c s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : H % g r o u n d m a s s : 1| % 28 p l a g i o c l a s e An c o n t : 5* q u a r t z o r t h o c l a s e V* s a n i d i n e a d u l a r i a 10 b i o t i t e 2, h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e h e m a t i t e m a g n e t i t e p y r i t e b c h l o r i t e e p i d o t e »^  c a r b o n a t e N f r T s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: Rock Name: o » V ^ S V t « . V \ v ^ o.\Ve*<-o\ av\oV*9 t"tt-G e o l o g i c a l U n i t : ""Too©\oo^OA/e, N j c l c a r o O * B. MAJOR ELEMENTS S102 T i 0 2 AL203 Fe203 FeO MnO MgO CaO Na20 K20 P205 C02 H20 5 1 - 3 5 © f l 2 . 3 ? 3.2/ o.U i-3>- 3.io 3 . H 8 .U ©11 l-3l I'll TRACE ELEMENTS N i Cr V S r Rb Ba Z r Nb Th Cu Au Ag I* I f I-To 2 0 S is n Si , I f HS" «l 71 PETROGRAPHIC DESCRIPTIONS E r u p t i v e Type/Mode o f O c c u r r e n c e a s h f l o w a g g l o m e r a t e b r e c c i a d y k e f l o w / b r e c c i a nuee a r d e n t e p y r o c l a s t i c T e x t u r e / S t r u c t u r e s a m y g d u l a r a p h a n i t i c banded b r e c c i a t e d c o a r s e d e v i t r i f i e d e u t a x i t i c embayed p h e n o c r y s t s e q u i g r a n u l a r f iamme f i n e f l o w banded f o l i a t e d s i l l s t o c k t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c w e l d e d t u f f g l o m e r p o r p h y r i t i c g r a d e d b e d d i n g g r a n i t i c g r a p h i c h y p i d i o m o r p h i c m a s s i v e m i c r o c r y s t a l l i n e y ^ m i n e r a l pseudomorphs p o r p h y r i t i c umiceous v e i n e d t r a c h y t i c v e s i c u l a r S t a t e o f P r e s e r v a t i o n ^ f r e s h ^ a l t e r e d 1. s l i g h t l y 2. m o d e r a t e l y V^3. e x t e n s i v e l y Type o f A l t e r a t i o n a r g i l l i c \ / c a r b o n a t i c c h l o r i t i c d e u t e r i c • ^ h y d r o t h e r m a l l e a c h e d • j p o t a s s i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — • s e r i c i t e p l a g i o c l a s e — r c h l o r i t e p l a g i o c l a s e • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — • c l a y s + a l u n i t e p l a g i o c l a s e — * q u a r t z • p l a g i o c l a s e —»potass ium f e l d s p a r • h e m a t i z e d p l a g i o c l a s e • h e m a t i z e d p o t a s s l u m " T e l d s p a r  • " p o t a s s i u m f e l d s p a r — * s e r c i t e h o r n b l e n d e — * c h l o r i t e + opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques h o r n b l e n d e — » opaques h o r n b l e n d e — * p r e h n i t e h o r n b l e n d e • q u a r t z b i o t i t e — * e p i d o t e + c h l o r i t e • ^ b i o t i t e — » c h l o r i t e c l inopyroxene—» c h l o r i t e + opaques c l i n o p y r o x e n e — * opaques p r e h n i t i c p r o p y l i t i c s e r i c i t i c • ' s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : % g r o u n d m a s s : 3a. 3 7 ( % p l a g i o c l a s e An c o n t : q u a r t z o r t h o c l a s e s a n i d i n e ? a d u l a r i a ? b i o t i t e h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e h e m a t i t e m a g n e t i t e p y r i t e • * * c h l o r i t e ^ e p i d o t e c a r b o n a t e — y a-i s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e \ g l a s s TOODOGGONE RIVER NTS: 94E A. HEADING INFORMATION Sample Number: \ \ O*^  Rock Name: o o V f c * H t a \ \ ^ * V W c < L a*vA*>Ttu Geological Unit: 1 o o d o ^ O j w A - V f t V ^ a m t i B. MAJOR ELEMENTS Si02 90 Ti02 AL203 Fe203 FeO 3-3*4 MnO 6. I f MgO I. »1 CaO *41 Na20 3.47 K20 P205 C02 I.6| H20 l . i , C. TRACE ELEMENTS Ni Cr V Sr Rb Ba Zr Nb Th Cu Au Ag >u 3 o r W7 /3 Vo Vo D. PETROGRAPHIC DESCRIPTIONS Eruptive Type/Mode of Occurrence ash flow agglomerate b r e c c i a dyke • / r l o w / b r ec c i a nuee ardente p y r o c l a s t i c Texture/Structures amygdular aph a n i t i c banded • ' b r e c c i a t e d coarse d e v i t r i f i e d e u t a x i t i c embayed phenocrysts equ igranular fiamme f i n e flow banded f o l i a t e d s i l l stock t u f f t u f f b r e c c i a v e i n v o l c a n o c l a s t i c welded t u f f glomerporphyritic graded bedding g r a n i t i c graphic hyp i d iomo rphic massive m i c r o c r y s t a l l i n e • mineral pseudomorphs l^n^porphyritic pumxceous • V e i n e d t r a c h y t i c v e s i c u l a r State of Preservation f r e s h . a l t e r e d 1. s l i g h t l y 2. moderately • a . extensively Type o f A l t e r a t i o n a r g i l l i c V c a r b o n a t i c c h l o r i t i c d e u t e r i c V h y d r o t h e r m a l l e a c h e d • p o t a s s i c p r e h n i t i c p r o p y l i t i c s e r i c i t i c y/" s i l i c i f i c a t i o n z e o l i t i c M i n e r a l A l t e r a t i o n s and R e p l a c e m e n t s p l a g i o c l a s e — * s e r i c i t e p l a g i o c l a s e — • c h l o r i t e p l a g i o c l a s e • e p i d o t e + s e r i c i t e + c a r b o n a t e + a l b i t e p l a g i o c l a s e — * c l a y s + a l u n i t e p l a g i o c l a s e — * q u a r t z • " p l a g i o c l a s e — > p o t a s s i u m f e l d s p a r h e m a t i z e d p l a g i o c l a s e  • ' h e m a t i z e d p o t a s s i u m f e l d s p a r  • " p o t a s s i u m f e l d s p a r — * s e r c i t e  ^ h o r n b l e n d e — * c h l o r i t e 4- opaques h o r n b l e n d e — * e p i d o t e + c h l o r i t e + opaques ho r n b l end e — » o pa qu es h o r n b l e n d e — * p r e h n i t e h o r n b l e n d e — » q u a r t z b i o t i t e — • e p i d o t e + c h l o r i t e • b i o t i t e — » c h l o r i t e c l i n o p y r o x e n e — * c h l o r i t e + opaques c l i nopyroxene—» opaques M i n e r a l A s s e m b l a g e % p h e n o c r y s t s : —~ % g r o u n d m a s s : —" 38 (f p l a g i o c l a s e An c o n t : j© q u a r t z (o r t h o c l a s e s a n i d i n e a d u l a r i a \\g b i o t i t e | h o r n b l e n d e b a s a l t i c h o r n b l e n d e c l i n o p y r o x e n e i r o n o x i d e | h e m a t i t e X. m a g n e t i t e p y r i t e tO c h l o r i t e e p i d o t e c a r b o n a t e s e r i c i t e a p a t i t e sphene l a u m o n t i t e d i c k i t e i l l i t e a l u n i t e a c t i n b l i t e z o i s i t e g l a s s APPENDIX MAPS 313 APPENDIX G: MAPS X-sl S p E O ^ U CoLWEtCTlotJS P l a t e I (map • poetegt) Toodoggone R i v e r a r e a G e o l o g i c Map P l a t e I I Cm-a^-pee+set) Shows l o c a t i o n o f r o c k samples s e l e c t e d f o r Whole-Rock and XRD a n a l y s i s P l a t e I I I (map-^D-ck-et) Toodoggone R i v e r a r e a C r o s s S e c t i o n s 

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