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UBC Theses and Dissertations

The giant mascot ultramafite and its related ores McLeod, James Albert 1975

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THE GIANT MASCOT ULTRAMAFITE AND ITS RELATED ORES  by  JAMES ALBERT McLEOD B.A.Sc., U n i v e r s i t y o f B r i t i s h Columbia,  1969  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTERS OF APPLIED SCIENCE  i n the Department of GEOLOGICAL SCIENCES  We a c c e p t t h i s  t h e s i s as conforming  to the r e q u i r e d  THE UNIVERSITY OF BRITISH COLUMBIA July,  1975  standard  In p r e s e n t i n g t h i s  thesis  an advanced degree at the L i b r a r y s h a l l I  f u r t h e r agree  in p a r t i a l  fulfilment of  the requirements f o r  the U n i v e r s i t y of B r i t i s h Columbia,  make it  freely available  that permission  for  I agree  r e f e r e n c e and  for e x t e n s i v e copying o f  this  that  study. thesis  f o r s c h o l a r l y purposes may be granted by the Head o f my Department or by h i s of  this  written  representatives. thesis  It  i s understood that c o p y i n g or p u b l i c a t i o n  f o r f i n a n c i a l gain s h a l l  not be allowed without my  permission.  Department o f  f-r £ o i t)C > f <xA J  The U n i v e r s i t y o f B r i t i s h 2075 Wesbrook P l a c e V a n c o u v e r , Canada V6T 1W5  Columbia  *b C \ e f U € <.  i  ABSTRACT  The  G i a n t  C r y s t a l l ine ( 1 x 2  Mascot  B e l t  m i . ) ,  100  m i l e s  east  c r u d e l y  zoned  ranging  b l e n d e - p y r o x e n i t e the  Spuzzum  have  been  mined  pyroxenites  at  m.y. 95  on  3050  i n  of  on  from  s o u t h e a s t e r n  massive  l e v e l  d i f f e r s  It  f l a n k  i s  of  the  roughly  through  e l l i p t i c a l  p y r o x e n i t e  e n c l o s e d  orebodies  Coast  i n  and  d i o r i t i c  w i t h i n  the  h o r n -  r o c k s  of  u l t r a m a f i t e  ores.  c r o s s - c u t from  It  i s  p i p e - l i k e  Ni-Cu  i n  B . C .  p e r i d o t i t e  h o r n b l e n d i t e .  composition  orebodies  the  Vancouver,  Twenty-eight  t h e i r  the  d a t i n g  to  119  m.y.  south  m a r g i n a l  i s  show  those  that  i n  composition  s i l i c a t e s  and  p e r l d o t i t e s .  from  s u l f i d e s  i n  Furthermore,  a c c e s s o r y  p e n t l a n d i t e  pent-  'in  r o c k s .  K-Ar 104  for  d i f f e r  from  u l t r a b a s i c  to  I n t r u s i o n s .  S t u d i e s  l a n d i t e  U l t r a m a f i t e  y i e l d s  m.y,  K-Ar  are  89  hornblende  age  of  85  m.y.  for  dykes,  a  border  and  a  orebodies the  Spuzzum D i o r i t e  T o n a l i t e ,  of  ages  Hornblendite  ages  m.y,  minimum  youngest  near  phase  b i o t i t e  age  and  the  r o c k s  mine  of  the  of  79  u l t r a m a f i t e  and  the  m i l e s  I n t r u s i o n s ,  c o n s i s t e n t  from  are  Eiine  s e v e r a l  Spuzzum m.y.,  i n  ranging  dated  to  the  y i e l d s  w i t h  a  e a r l i e r  i n v e s t i g a t i o n s .  Temperatures from  the  3050  D i s t r i b u t i o n  c a l c u l a t e d  l e v e l  from  c r o s s - c u t  c o e f f i c i e n t s  15  average  c o e x i s t i n g 990°C  (mean K j ) = 0 . 7 3 8 )  f o r  for  c l i n o -  and  orthopyroxene  e q u i l i b r a t i o n  these  s i l i c a t e s  of  these  suggest  p a i r s  s i l i c a t e s . a  magmatic  o r i g i n .  The plunging or  Climax  p i p e - l i k e ,  f o o t w a l l .  r e l a t e d  It  and  to  i s  They  Chinaman  bodies are  orebodies  w i t h  found  at  higher  on  grade  the  3050  l e v e l  s e c t i o n s  c r o s s - c u t  c o n c e n t r a t e d  p e r i d o t i t e - p y r o x e n i t e  c o n t a c t s  and  are  i n  s t e e p l y  the  appear  trough s p a t i a l l y  n o r i t e .  concluded  re-emplacement  of  that  c r u d e l y  the  Giant  s t r a t i f o r m  Mascot c r y s t a l  U l t r a m a f i t e mushes  and  o r i g i n a t e d s u l f i d e  by  melts  c l i a p i r i c from  a  d i f f e r e n t i a t i n g s u b - v o l c a n i c magma chamber, p o s s i b l y a n e a r l y phase o f Spuzzum magmatic a c t i v i t y .  T h i s m a t e r i a l was s u b s e q u e n t l y  e n g u l f e d by  r i s i n g Spuzzum d i o r i t i c magmas w h i c h superimposed a h o r n b l e n d i t e the u l t r a m a f i t e .  r i m 01  Ill  TABLE OF CONTENTS page Abstract  i  Acknowledgements  i i i  Introduction  1  (i) Location  1  ( i i ) G e n e r a l Statement ( i i i ) History  1 1  (iv) Previous I n v e s t i g a t i o n s R e g i o n a l Geology  2 4  (i) Regional S e t t i n g  4  ( i i ) S t r a t i f i e d Rocks  4  ( i i i ) M e t a s e d i m e n t a r y Rocks (iv) Gneiss  6  (v) G r a n i t o i d Rocks (vi) U l t r a m a f i t e s  6 6  (vii) Structures  7  L o c a l Geology  9  (i) Introduction  9  ( i i ) Metamorphic Rocks ( i i i ) U l t r a b a s i c Rocks ( i v ) F e l d s p a t h i c Rocks (v) O r e b o d i e s  9 10 11 11  P e t r o l o g y o f t h e 3050 L e v e l C r o s s - C u t ( i ) G e n e r a l Statement (ii) Classification  5  o f Rock Types  13 13 13  iv page ( i i i ) D e s c r i p t i o n o f Rock Types  14  (1) . N o r i t e  14  (2) U l t r a b a s i c Rocks  16  M i n e r a l i z a t i o n and Orebodies  25  (i) Introduction  25  ( i i ) Disseminated S u l f i d e s  25  ( i i i ) Net-Textured S u l f i d e s  27  (iv) Massive S u l f i d e s (v) T e x t u r a l  Relations  28 Between t h e V a r i o u s  Sulfides  31  (vi) Paragenesis  31  ( v i i ) C l i m a x Orebody  38  ( v i i i ) Chinaman Orebody  40  Chemical Analyses of S i l i c a t e s  and S u l f i d e s  48  ( i ) S i l i c a t e A n a l y t i c a l Techniques  48  ( i i ) S i l i c a t e Analyses (iii)  48  S u l f i d e A n a l y t i c a l Techniques  (iv) S u l f i d e Analyses  53 53  Thermal H i s t o r y o f t h e U l t r a b a s i c Complex (i) Introduction  58 58  ( i i ) Methods  60  ( i i i ) Discussion  and I n t e r p r e t a t i o n  O r i g i n of the U l t r a m a f i t e Conclusions References C i t e d  '. . . .  and i t s Ores  70 73 83  .  85  page Appendix  1. - Sample L o c a t i o n Map  89  Appendix  2. - Geology o f C l i m a x , 3050 L e v e l  90  Appendix  3. - Cu, N i , and Cu/(Cu+Ni) Assay Contour Maps o f Chinaman and C l i m a x Orebodies  92  Appendix  4. - M i c r o p r o b e A n a l y s e s o f S i l i c a t e s  108  Appendix  5. - M i c r o p r o b e A n a l y s e s o f S u l f i d e s  117  Appendix  6. - U n i v e r s a l Stage Determinations  Composition 123  vi FIGURES page Fig.  1.  L o c a t i o n and T e c t o n i c Map o f B.C  3  Fig.  2.  G e n e r a l i z e d Geology o f t h e N o r t h e r n Cascades R e g i o n  Fig.  3.  Geology and M i n e r a l i z a t i o n  5 (Giant  Mascot Mine) Fig.  4.  10  C l a s s i f i c a t i o n and Nomenclature o f U l t r a m a f i c Rocks  14 17  Fig.  5.  Photograph o f N o r i t e - P y r o x e n i t e C o n t a c t ....  Fig.  6.  Photograph o f Complex Age R e l a t i o n s h i p of N o r i t e t o U l t r a b a s i c Rocks  17 18  Fig.  7.  Photomicrograph o f S t r a i n e d O l i v i n e Grains .  Fig.  8.  P h o t o m i c r o g r a p h o f Cumulus-Like  Olivines  • i n P o i k i l i t i c G r a i n o f Hornblende Fig.  9.  P h o t o m i c r o g r a p h o f Cumulus-Like Orthopyroxenes i n P o i k i l i t i c Hornblende  F i g . 10.  F i g . 11.  ....  19  ( W e b s t e r i t e and O l i v i n e - R i c h P y r o x e n i t e ) ...  23  Photograph o f Sharp C o n t a c t a t 7260 N.  Photomicrograph of O l i v i n e Grains i n Hornblende  F i g . 12.  13.  23  Photograph o f F i n e G r a i n e d H o r n b l e n d i t e Dyke C u t t i n g A n o t h e r H o r n b l e n d i t e Dyke  Fig.  18  24  Photograph o f One F o o t Wide H o r n b l e n d i t e Dyke w i t h R e a c t i o n M a r g i n  24  vii page Fig.  14.  Photomicrograph o f I n t e r s t i t i a l  Po-Pn-Cpy  Grains i n Fresh Pyroxenite Fig.  15.  26  P h o t o m i c r o g r a p h o f Composite Po-Cpy B l e b and M a g n e t i t e G r a i n E n c l o s e d i n O l i v i n e  Fig.  16.  Photomicrograph o f Net-Textured S u l f i d e s  Fig.  17.  Photomicrograph o f Massive S u l f i d e s  Fig.  18.  Photograph o f P r o t o c l a s t i c T e x t u r e o f  ....  26  ...  29  Chinaman Ore Fig.  19.  30  P h o t o m i c r o g r a p h o f Cpy on Edge o f Composite G r a i n S e p a r a t e d from Po by Pn  Fig.  20.  21.  22.  23.  Low Temperature Ni-Cu Ores  36 37  24.  Apparant Paragenesis  Fig.  25.  N i Contour P l o t o f C l i m a x Ore a t 3108' Elevation,  26.  27.  i n Percent  41  Cu Contour P l o t o f C l i m a x Ore a t 3108' Elevation,  Fig.  35  M i n e r a l Assemblages i n  Fig.  Fig.  33  Schematic 850° I s o t h e r m a l Diagram o f t h e Cu-Fe-Ni-S System  Fig.  32  Schematic 1000°C I s o t h e r m a l Diagram o f the Cu-Fe-Ni-S System  Fig.  30  Photomicrograph o f C h a l c o p y r i t e R e p l a c i n g Fractures i n S i l i c a t e s  Fig.  29  i n Percent  41  Cu / (Cu+Ni) P l o t o f C l i m a x Ore a t 3108' E l e v a t i o n , Ratio i n Percent  42  viii page F i g . 28.  Ni Contour P l o t of Chinaman Ore 3160'  Fig.  29.  30.  Cu / 3160'  Fig.  31.  Elevation,  32.  44 at  i n Percent  45  (Cu+Ni) P l o t of Chinaman Ore Elevation, Ratio  at  i n Percent  46  Q u a d r i l a t e r a l P l o t of Pyroxene Compositions  Fig.  i n Percent  Cu Contour P l o t o f Chinaman Ore 3160'  Fig.  Elevation,  at  3050 Cross-Cut  50  Elemental V a r i a t i o n i n Orthopyroxene 3050 Cross-Cut  F i g . 33.  51  Elemental V a r i a t i o n i n C l i n o p y r o x e n e 3050 Cross-Cut  Fig.  34.  Fe-Ni-S P l o t s of C o e x i s t i n g and  F i g . 35.  52 Pyrrhotite  Pentlandite  ••••  Elemental V a r i a t i o n i n  Pentlandite  3050 Cross-Cut F i g . 36.  Mg  and  56  Fe D i s t r i b u t i o n C o e f f i c i e n t  - o f Pyroxenes a t G i a n t Mascot Fig.  (Kp) ,  37.  Location  o f K-Ar  D a t i n g at G i a n t Mascot  F i g . 38.  Location  of K-Ar  D a t i n g of Spuzzum  P l u t o n i c Rocks  54  59 ....  66  69  ix TABLES page T A B L E 1.  - C l i m a x Ore C a l c u l a t i o n s  39  T A B L E 2.  - Chinaman  43  T A B L E 3.  - Temperature Pyroxene  T A B L E 4.  Ore C a l c u l a t i o n s Data of  Pairs  - K-Ar Samples Ultrabasic Mascot  and K  Coexisting Q  Values  and A n a l y t i c a l  and P l u t o n i c  Property,  62 Results  Rocks  For  at the Giant  n e a r H o p e , B.C.  72  ACKNOWLEDGEMENTS  T h i s t h e s i s was to whom the author  done under the k i n d s u p e r v i s i o n of Dr. K.C.  i s very  indebted.  G i a n t Mascot Mines L t d . , i s thanked f o r t h e i r and  f o r p r o v i d i n g f u l l access  Mr.  F. H o l l a n d  and Mr. and  R.  McTaggart  financial assistance  to the G i a n t Mascot Mine.  (mine g e n e r a l manager), Mr.  In a d d i t i o n ,  L. DeRoux ( c h i e f mine g e o l o g i s t )  Gonzales ( e x p l o r a t i o n g e o l o g i s t ) a r e thanked f o r t h e i r h e l p  hospitality. Mr.  sampling  D.P.  Moore's i n v a l u a b l e a s s i s t a n c e i n underground mapping  and h i s asjtute o b s e r v a t i o n s a r e g r a t e f u l l y a p p r e c i a t e d .  p h y s i c a l support Dr. T.H. with  and His  made t h i s work p o s s i b l e .  Brown i s thanked f o r h i s h e l p and  the departments microprobe.  Mr.  advice i n  connection  A. L a c i s of t h e Department of  M e t a l l u r g y i s thanked f o r h i s h e l p i n the o p e r a t i o n o f t h a t departments microprobe.  Also., Mr.  J . Harakal's  h e l p i n K-Ar  age  determinations  is  appreciated. Dr. P.  C h r i s t o p h e r of the B.C.  Resources was  Department o f M i n e s and  Petroleum  of, a s s i s t a n c e i n s u p p l y i n g some d a t a about the G i a n t Mascot  Mine. A p p r e c i a t i o n i s extended to the t e c h n i c a l s t a f f f o r t h e i r generous "behind this  the scenes" h e l p and  of the  to Ann  department  Carr f o r typing  manuscript. The  a u t h o r wishes to extend  c o l l e a g u e s whose m o r a l support h i s wife  Joanne.  h i s g r a t i t u d e to a l l those  proved i n v a l u a b l e and,  f r i e n d s and  in particular,  to  INTRODUCTION  Location G i a n t Mascot Mine l i e s B.C.  and  7 m i l e s n o r t h w e s t of the  90 m i l e s e a s t of Vancouver, ( l a t i t u d e 49°  longitude  121°  7 m i l e s and  30' W).  town of Hope,  28' W.,  and  A c c e s s from Hope i s by paved highway f o r  then 5 m i l e s of g r a v e l road which winds westward i n t o  the rugged C o a s t Range mountains.  General  Statement  The along  s u b j e c t o f t h i s study  i s the geology and m i n e r a l i z a t i o n  the 3050 c r o s s - c u t , which g i v e a c c e s s  worked o r e b o d i e s The w r i t e r and the s p r i n g o f mine r e c o r d s  to the two  o f G i a n t Mascot mine, - the C l i m a x and  a c o l l e a g u e spent 1973  mapping and  approximately  most r e c e n t l y the Chinaman.  t h r e e weeks ..during  sampling the c r o s s - c u t and  of the a r e a o f i n t e r e s t .  assembling  A d d i t i o n a l sampling  and  specimen c o l l e c t i o n were made l a t e r d u r i n g s e v e r a l b r i e f v i s i t s  to  the mine. T h i n - s e c t i o n s and p o l i s h e d s e c t i o n s were s t u d i e d under microscope, and by e l e c t r o n m i c r o p r o b e , and K-Ar for  ages were determined  u l t r a b a s i c r o c k s which c o n t a i n the o r e d e p o s i t s and  surrounding  1923.  f o r the  p l u t o n i c rocks.  History  '  The  the  •  .  :  showings of the G i a n t Mascot p r o p e r t y were d i s c o v e r e d  E x p l o r a t i o n work was  c a r r i e d on between 1923  and  1937  in  and  a g a i n between 1951  and  uction  operated c o n t i n u a l l y u n t i l  i n 1958  and  1954.  The  p r o p e r t y was  brought i n t o p r o d shut down i n September  1974.  Previous  Investigations  Early investigators (1933), and  include  Horwood (1937).  C a i r n e s (1924), C o c k f i e l d and  Their conclusions  c o n f l i c t w i t h r e g a r d to the o r i g i n o f ained mineralization surrounding d i o r i t e s .  and  Aho  comprehensive a c c o u n t of genesis. Mascot. a new  the  in  considerable  the u l t r a b a s i c r o c k s and  r e l a t i o n s h i p of u l t r a m a f i t e s  cont-  to  the  (1956) p r o v i d e s the most d e t a i l e d  and  the u l t r a m a f i t e ,  R e c e n t l y , M u i r (1971) s t u d i e d The  are  Walker  Department of Mines and  i n v e s t i a g i o n of the mine.  the o r e b o d i e s , and  their  the 4600 orebody a t G i a n t .  P e t r o l e u m Resources has  started  3  4  REGIONAL GEOLOGY  Regional Setting The eastern  u l t r a b a s i c complex a t G i a n t f l a n k of  the C o a s t and  the Coast C r y s t a l l i n e B e l t , near the  Cascade mountain systems ( F i g . 1).  a l l i n e B e l t i s one as d e f i n e d illustrates  by  The  Sutherland-Brown e t . a l . , (1971).  the v a r i o u s  south-  junction Coast  o f u n i f o r m s t r a t i g r a p h y , s t r u c t u r e and A map  of  Cryst-  metallogeny  ( F i g . 2)  rock u n i t s p r e s e n t i n the r e g i o n  rock u n i t s are described  Stratified  Mascot mine l i e s a t the  and  these  below.  Rocks  Hozameen Group This well s t r a t i f i e d east  side.  The  Group c o n s i s t s of p e l i t i c r o c k s ,  v o l c a n i c r o c k s and i n general  to a low  writers believed  The of  grade but  be  chert,  the  basic  to h i g h  grade.  l a t e Paleozoic,  as young as  Most e a r l y  b u t Monger (1970)  Triassic.  Group the C h i l l i w a c k  the Hozameen Group.  to the  locally  the r o c k s to be  l i t h o l o g y of  s t o n e s , and  r o c k s on  l i m e s t o n e t h a t have been r e g i o n a l l y metamorphosed  s u g g e s t s t h a t they may  Chilliwack  group f l a n k s the b a t h o l i t i c  Group i s more c l a s t i c  S t r a t i g r a p h i c u n i t s are m o s t l y p e l i t e s ,  s i l t s t o n e s with l e s s e r v o l c a n i c rock.  immediate west o f b a t h o l i t i c r o c k s d e s c r i b e d  to be P e n n s y l v a n i a n and grade r e g i o n a l , b u t  high  than  Permian i n age. grades are  This and  group  sand-  lies  i s believed  Metamorphism i s m o s t l y  encountered i n the  that  north.  low  GRANITIC PLUTONS LATE  [73  TERTIARY  MID-TERTIARY 1+ +|  CRETACEOUS?  \Q<y\  JURASSIC?  Gw'chon BathotiD*  0.  LAYERED ROCKS C - C H U C K A N U T GP J-K - J U R A S S I C - C R E T \ t M-MESOZOIC . \ P-PALEOZOIC (221  GNEISS  A  PERIDOTITE  | CHILLIWACK GR  From McTaggart (1970) Figue  2  : Generalized  g e o l o g y o f the N o r t h e r n  Evfl Cascades  H O Z A M E E N GR  Region.  Metasedimentary and M e t a v o l c a n i c Rocks N o r t h o f the F r a s e r R i v e r n e a r Hope, p e l i t i c s c h i s t ,  phyllite  and a m p h i b o l i t e o f h i g h grade B a r r o v i a n s t y l e metamorphism a d j o i n the Scuzzy  and Spuzzum p l u t o n s .  b u t on the b a s i s o f c o m p o s i t i o n Upper P a l e o z o i c Hozameen Group.  The age o f t h e s e r o c k s i s u n c e r t a i n , they a r e p r o b a b l y formed from the The age o f metamorphism i s thought  to be r o u g h l y contemporaneous w i t h L a t e C r e t a c e o u s (McTaggart and Thompson, morphism p r e c e d e d  1967).  plutonism  Read (1960) s u g g e s t e d  t h a t meta-  p l u t o n i s m , as s t a u r o l i t e and s i l l i m a n i t e i s o g r a d s  do n o t p a r a l l e l the c o n t a c t of t h e Spuzzum P l u t o n .  6  Gneiss In  the Hope a r e a the C u s t e r G n e i s s l i e s between metasedimentary,  metavolcanic, Group and  and b a t h o l i t i c r o c k s to the west and  d i m i n i s h e s to the n o r t h i n a w e d g e - l i k e  the Hozameen fashion.  This  r o c k c o n s i s t s o f l a y e r e d a m p h i b o l i t e , l e u c o c r a t i c g n e i s s , augen g n e i s s , minor marble and uncertain.  Z i r c o n s dated by M a t t i n s o n  and he s u g g e s t s Upper  t r o n d h j e m i t e pegmatite..  The  age of  the g n e i s s i s  (1970) y i e l d Precambriah  an e p i s o d e of metamorphism and m i g m a t i z a t i o n  ages  i n the  Cretaceous.  G r a n i t o i d Rocks The  Spuzzum and  Scuzzy P l u t o n i n the north.and  the C h i l l i w a c k  P l u t o n i n the south form a n o r t h - t r e n d i n g heterogeneous b e l t of granitic  r o c k s p a s s i n g j u s t west o f Hope and Y a l e .  P l u t o n , which c o n s i s t s of d i o r i t e and Cretaceous  ( R i c h a r d s , 1971)  mesozonal.  The  contiguous  (Roddick and H u t c h i s o n ,  and has been c l a s s i f i e d as c a t a z o n a l to Scuzzy P l u t o n to the n o r t h i s d e s c r i b e d  1969)  as a g r a n o d i o r i t e , b u t has  The age o f t h i s p l u t o n i s L a t e  (Hutchison,  Richards  and  quartz d i o r i t e i t s age  suggest  Cenozoic  to n i n e phases, b u t c o n s i s t i n g  to g r a n o d i o r i t e .  (26-29 my),  definite  Cretaceous  (1971) d e s c r i b e s the l a t e  C h i l l i w a c k P l u t o n as h a v i n g up of  Spuzzum  t o n a l i t e i s considered Late  trondhjemite t r e n d . 1970).  The  S t r u c t u r a l and  t h a t i t was  mainly  textural features  emplaced i n the  epizone.  Ultramafites U l t r a m a f i c r o c k s l i e to the e a s t and west of the Spuzzum Batholith.  The  e a s t e r n body, the C o q u i h a l l a S e r p e n t i n e B e l t  ( C a i r n e s , 1930)  .7  i s of the a l p i n e type and Group. Bar  forms the e a s t e r n c o n t a c t o f the Hozameen  T h i s b e l t runs from 16 m i l e s s o u t h - e a s t  a d i s t a n c e of 40 m i l e s and  p e r i d o t i t e , p y r o x e n i t e and rocks  o f Hope to B o s t o n  c o n s i s t s of s e r p e n t i n e , s e r e p e n t i n i z e d  gabbro.  The  u l t r a m a f i t e and  the Hozameen  to the west form a t y p i c a l o p h i o l i t e s u c c e s s i o n and may  been emplaced as an obducted To  have  slice.  the west, a l e s s w e l l d e f i n e d b e l t composed o f s m a l l  of p y r o x e n i t e , p e r i d o t i t e , h o r n b l e n d i t e , d u n i t e and appears f a u l t c o n t r o l l e d .  bodies  gabbroic  rocks  North o f the F r a s e r R i v e r t h i s f a u l t ,  the  Shuksan T h r u s t , marks the e a s t e r n boundary o f the C h i l l i w a c k Group. T h i s b e l t extends from the b o r d e r  to The  then swings a b r u p t l y north-west.  Much o f the u l t r a m a f i c r o c k i s  s e r p e n t i n i z e d and  c l a s s e d as a l p i n e  A c r u d e l y zoned body r a n g i n g to p e r i d o t i t e l i e s on diorite.  O l d S e t t l e r mountain,  type.  from h o r n b l e n d i t e  through  pyroxenite  the v e r y e a s t e r n edge, but w i t h i n the Spuzzum  T h i s body, the G i a n t Mascot U l t r a m a f i t e , i s d e s c r i b e d i n  g r e a t e r d e t a i l i n the f o l l o w i n g s e c t i o n . E x p l o r a t i o n by G i a n t Mascot Mines i n the v i c i n i t y of The S e t t l e r mountain has and  lithologically  revealed u l t r a b a s i c rocks that are  similar  rocks are coarse-grained, The  texturally  to the G i a n t Mascot U l t r a m a f i t e . f r e s h h o r n b l e n d e p y r o x e n i t e s and  These peridotites.  c o n t a c t r e l a t i o n s h i p s o f these u l t r a m a f i c r o c k s w i t h the  rocks  tends to be ambiguous and  conflicting  (K.C.  Old  dioritic  McTaggart, p e r s . comm.).  Structures The  overall structural  Major f a u l t  t r e n d of the a r e a i s r o u g h l y n o r t h e r l y .  systems i n c l u d i n g the Shuksan t h r u s t on  t h e west,  the  8  Hope and and  Yale  f a u l t s on  the immediate e a s t e r n  f l a n k o f the b a t h o l i t h  the Hozameen f a u l t i n the e a s t a l l t r e n d n o r t h e r l y o r n o r t h w e s t .  These f a u l t systems i n t u r n separate northerly  trending b e l t s .  t r e n d i n g axes.  According  and  d e l i n e a t e major l i t h o l o g i c a l  F o l d i n g tends to be  along  to Read ( p e r s . comm.) metamorphism i n c r e a s e s  from b o t h e a s t and west towards the b a t h o l i t h i c r o c k s Cascades and  northwest  south e a s t e r n Coast mountains.  of the  northern  LOCAL GEOLOGY  Introduction The  p r e s e n t d e s c r i p t i o n of the geology  around the G i a n t Mascot mine  draws on the f i e l d work o f s e v e r a l a u t h o r s , b u t mainly  on the d e t a i l e d  work o f Aho (1956). The  G i a n t Mascot U l t r a m a f i t e i s a p p r o x i m a t e l y  2 m i l e s l o n g i n the  east-west d i r e c t i o n and 1 m i l e wide i n a n o r t h - s o u t h  direction.  In p l a n  the body appears v e r y i r r e g u l a r w i t h many s a l i e n t s and r e - e n t r a n t s surrounding  diorite.  I n the s o u t h e a s t  corner  with  the complex i s i n c o n t a c t  w i t h , o r v e r y c l o s e t o , h i g h grade metamorphic r o c k s .  A  simplified  g e o l o g i c a l p l a n i s shown i n ( F i g . 3) a f t e r Aho (1956).  Metamorphic Rocks Metamorphic r o c k s form i n c l u s i o n s w i t h i n the u l t r a m a f i t e and the d i o r i t e and may abut the complex on the s o u t h e a s t a r e mica s c h i s t s , l o c a l l y w i t h garnet, probably  corner.  These  kyanite or s t a u r o l i t e .  rocks  They  a r e h i g h grade e q u i v a l e n t s o f the Upper P a l e o z o i c Hozameen  Group which they resemble i n c o m p o s i t i o n  (Monger, 1970).  The r o c k s  belong  to the s t a u r o l i t e - a l m a n d i n e s u b f a c i e s o f t h e almandine-amphi-  bolite  f a c i e s o f B a r r o v i a n metamorphism.  C o n t a c t metamorphism by the  u l t r a m a f i t e has produced'orthopyroxene s u b f a c i e s r o c k o f the o r t h o c l a s e cordierite-hornfels facies  (Aho, 1956), b e l i e v e d to i n d i c a t e temper-  a t u r e s of a t l e a s t 600°C.  T h i s would i n d i c a t e a s o l i d u s temperature o f  •at l e a s t  1000°C f o r the u l t r a m a f i t e ( W i n k l e r ,  1967, pp.79-83).  10  ,  , T  -i" i - . 4=.< i-  + -f + + 4,  J - . +  +  +  +T+  f  i, f -f/,+  ;- + -!• +  , + ,+  + •• T  / + +  -V Y  ;- + + + +  +• +  - +• + -f-JdfA"-+"- + t- -t+ -)1  + + +-  +, + +AT,++ *•+-  + ;+ -r +-  + -f + + ,+ + -+  -+-  +  +-  •+ + -t- -h  1  ,+ ,+ + -T , , T- -r- -r- - « + + + + + f- + + + + + -f + • + +  ,  • + + + + + + + -K^e •+ + + + + +-+• + + +•+.+ • i  i  i  i  i  v  i  I I  _L I I  I  Mdirt,  Miaou  MMlTt  AMD M I N E R A L I S A T I O N  PACIFIC  NICKEL  6CAut _»000  MINES  OP r c t T BOOQ 4oyg  O M C MIL.ft  from Aho (1956)  Fig.3  U l t r a b a s i c Rocks Aho (1956) was the f i r s t  to p o i n t o u t a crude  z o n a t i o n o f the u l t r a -  b a s i c complex which c o n s i s t s e s s e n t i a l l y o f p y r o x e n i t e w i t h c o r e s o f peridotite.  The p y r o x e n i t e becomes i n c r e a s i n g l y h o r n b l e n d i c outwards and a  remarkable margin, up to 100 yards wide, o f c o a r s e - g r a i n e d h o r n b l e n d i t e i s p r e s e n t a t the d i o r i t e - u l t r a b a s i c  contact.  The  r e l a t i v e age  of  the d i o r i t e and  the u l t r a m a f i t e i s  s e v e r a l authors h o l d i n g c o n f l i c t i n g opinions. i n a l a r g e p a r t the u l t r a b a s i c rocks been observed by  Cairnes  (1924).  r e l a t i o n i s seen i n some p l a c e s dioritic  rocks.  C o c k f i e l d and  b a s i c s were i n t r u d e d by there  i s a strong  that  the d i o r i t e s as  does concede t h a t  the  had  reverse  distinguishes several different  Walker (1933) c o n c l u d e d t h a t the  surrounding d i o r i t e .  genetic  (1956) found  appear to cut  Aho and  Aho  unresolved,  ultra-  Most a u t h o r s s t r e s s  r e l a t i o n s h i p between u l t r a b a s i c and  that  the  surrounding f e l d s p a t h i c rocks.  F e l d s p a t h i c Rocks The  p r i n c i p a l c o u n t r y r o c k around the u l t r a m a f i t e c o n s i s t s o f  d i o r i t e , n o r i t e and  tonalite.  These r o c k s  generally  contain  plagio-  c l a s e of a n d e s i n e to l a b r a d o r i t e c o m p o s i t i o n , h y p e r s t h e n e , d i o p s i d i c augite,  l e s s e r h o r n b l e n d e and b i o t i t e and  These r o c k s have been grouped t o g e t h e r  a v a r y i n g amount of  as p a r t of  the  quartz.  complexly  d i f f e r e n t i a t e d Spuzzum P l u t o n o f Upper C r e t a c e o u s age.  Large i n -  t r u s i o n s o r x e n o l i t h s o f d i o r i t e and  within  u l t r a m a f i t e , but  Orebodies  n o r i t e are present  t h e i r r e l a t i o n to the Spuzzum p l u t o n  i s not c e r t a i n .  ' .  More than 28 o r e b o d i e s have been l o c a t e d w i t h i n the They o c c u r as  steeply plunging,  p i p e - l i k e ore  c l a s s i f i e d as e i t h e r zoned o r m a s s i v e , The  the  zoned o r e b o d i e s are  (Aho,  zones and  ultramafite. have been*  1956).  c i r c u l a r or e l l i p t i c a l  i n plan,  pipe-  l i n e i n s e c t i o n , x^ith m i n e r a l i z a t i o n c o n c e n t r i c a l l y d i s t r i b u t e d around  12  an o l i v i n e - r i c h  c o r e o f p e r i d o t i t e o r w i t h i n the core i t s e l f .  The  p e r i o d i t e g i v e s way to an o l i v i n e p y r o x e n i t e and outward to o r t h o pyroxenite.  M i n e r a l i z a t i o n i s g r a d a t i o n a l to b a r r e n r o c k .  o f o r e was b e l i e v e d to be o f replacement  This  type  origin.  The massive ore-bodies o c c u r as more i r r e g u l a r p i p e - l i k e s t r u c t u r e s and  appear to be unzoned.  The o r e i s p r e s e n t as a u n i f o r m  groundmass  of s u l f i d e s u r r o u n d i n g s i l i c a t e g r a i n s a t l i t h o l o g i c c o n t a c t s between v a r i o u s u l t r a m a f i c rock types.  These o r e s g e n e r a l l y have sharp  w i t h w a l l rock but;may grade i n t o d i s s e m i n a t e d o r e s . o r e b o d i e s show m a r g i n a l " f l o w l i n e s " , banding, e s t i v e o f magmatic i n j e c t i o n ,  (Aho, 1956).  Commonly  and " d r a g  contacts these  folding"  sugg-  Aho s t a t e s t h a t these two  c a t e g o r i e s may be end members of a continuum, as some o r e zones have features of both c a t e g o r i e s .  PETROLOGY OF THE  3050 LEVEL CROSS-CUT  G e n e r a l Statement The  3050 l e v e l  ( F i g . 37) c r o s s - c u t  6400N to 8600N and mapped a t 1" = 20'. g e o l o g i c map  was  washed and  Sample l o c a t i o n s and  o f the Climax a r e a a r e appended.  samples were chosen  sampled  from a  Representative rock  for thin sectioning for detailed petrological  study. Mineralogical  determinations of s i l i c a t e  made by u n i v e r s a l s t a g e and e l e c t r o n  c o m p o s i t i o n s were  probe.  C l a s s i f i c a t i o n of Rock Types The  following rock c l a s s i f i c a t i o n  (1967) was  used by  ( F i g . 4) a f t e r  the author, w i t h s l i g h t  Streckeisen  modifications.  F e l s i c Rocks: Diorite.  . . . . . . .  mainly a d e s i n e o r o l i g o c l a s e , hornblende  Norite  . . . . . . . . . . . . . .  major m a f i c .  mainly bytownite orthopyroxene  or l a b r a d o r i t e ,  major m a f i c .  Hornblendite: . . . . . . . . . . . . . .  hornblende, plagioclase,  80  -  100%,  0-20%.  14  Pendotiie's horzfcurqite  olivine orlhopyroienite  /  1  ol ivme cltnopyrOxenile.  Pyroseniles  0  OTlhopjTOx^mle  clinopyroienile  Ultramafic rocks composed cf olivine, orthopyroxene, and dinopyroxene. . .; Ultramafic rocks that contain hornblende.  Pendoiiles  Pyro*eni1es  olivine pyroxenites  pyroxenites  or.d Homblendiles  pyroxene hornblendite  hornblendite  •'. Classification and nomenclature of (+ Bi + Car + Sp) St 95; opaque minvitramafic rocks. 01 + Opx + Cpx + Hbl erals =£ 5.  Fig. 4  D e s c r i p t i o n o f Rock Types Norite  N o r i t e occurs along the 3050 l e v e l cross-cut as i n c l u s i o n s , host and fragments i n b r e c c i a and as apophyses i n t o more b a s i c m a t e r i a l . The rock i s medium grained, l i g h t coloured, and shows a strong alignment of mafic m i n e r a l s .  15  N o r i t e i s composed o f i n t e r l o c k i n g s u b h e d r a l p l a g i o c l a s e l a t h s w i t h m a f i c c o n t e n t u s u a l l y l e s s than 40%.  P l a g i o c l a s e i s as c a l c i c as An90  i n some i n c l u s i o n s and as s o d i c as An65 i n apophyses. is are  a c c e n t u a t e d by d u s t i n c l u s i o n s which  lend  Normal z o n i n g  them a p i n k i s h t i n t .  p r o b a b l y h e m a t i t e produced by metamorphism.  Very l i t t l e  These  inter-  s t i t i a l q u a r t z i s p r e s e n t i n these r o c k s . H y p e r s t h e n e , m o s t l y s u b h e d r a l , the dominant pyroxene, c o n t a i n s " s c h i l l e r " i n c l u s i o n s and p a t c h e s o f c l i n o p y r o x e n e e x s o l u t i o n Many o f the g r a i n s a r e c o r r o d e d o r rimmed by a p a l e green, amphibole  actinolite  o r rimmed o r r e p l a c e d by green-brown h o r n b l e n d e .  a n h e d r a l a u g i t e forms c l o t s around orthopyroxene and s t a g e s o f r e p l a c e m e n t from the c o r e t o r i m by  lamellae.  Subordinate  showsvarious  hornblende.  Brown to green h o r n b l e n d e i s u b i q u i t o u s , rimming  or r e p l a c i n g  pyroxenes  or f o r m i n g p o i k i l i t i c g r a i n s e n c l o s i n g pyroxenes  ioclase.  M a g n e t i t e i s p r e s e n t as p r i m a r y e u h e d r a l g r a i n s and as a  p r o d u c t o f a l t e r a t i o n of pyroxenes.  and  plag-  Sulfidesare present i n various  amounts, u s u a l l y as wormy, i n t e r s t i t i a l a g g r e g a t e s o r b l e b s . A n o r i t e i n c l u s i o n encountered about  150'  south o f t h e Climax o r e  a few f e e t a c r o s s i s f r e s h n o r i t e i n the c e n t e r becoming f i n e r g r a i n e d toward which  zone,  increasingly  the margin, and i s a h o r n f e l s a t the margin,  intertongues with pyroxenite.  The m i n e r a l o g y i s p l a g i o c l a s e  orthopyroxene and suggests h i g h temperature  and  (700°C) c o n t a c t metamorphism.  From 8000N. t o 8350N. many i n c l u s i o n s o f n o r i t e form sharp  ( F i g . 5) to  g r a d a t i o n a l c o n t a c t w i t h u l t r a b a s i c r o c k and i n p l a c e s a c t u a l l y i n corporate u l t r a b a s i c material. accompanied  These  i n c l u s i o n s and apophyses  by many h o r n b l e n d e - r i c h c l o t s and dykes.  Figure 6,  are u s u a l l y demonstrates  16  the complex and u n c e r t a i n age r e l a t i o n s o f the n o r i t e w i t h  ultrabasic  rock.  Ultrabasic (1)  Rocks  Mineralogy  The u l t r a b a s i c r o c k s encountered f r e s h orthopyroxenes spars a r e s c a r c e .  and c l i n o p y r o x e n e s , o l i v i n e s and hornblende.  r i c h rocks to  show some d e f o r m a t i o n  (Figs.  8 and 9 ) .  ( F i g . 7).  G r a i n s i z e o f these r o c k s range from  c o a r s e b u t a r e g e n e r a l l y medium, t h a t i s 1-5 mm.  G r a i n s range  Pyroxenes g r a i n s a r e s u b h e d r a l , o l i v i n e s  o c c u r as c o r r o d e d o r wormy s u b h e d r a l g r a i n s and hornblende  as a n h e d r a l p o i k i l i t i c , Cumulus-like  interstitial,  o r replacement  stage replacement  o f ortho-and  g r a i n s o f hornblende  The more M g - r i c h  i n t h e more o l i v i n e - r i c h p e r i d o t i t e s . v e i n l e t s and shows t y p i c a l  do h o r n b l e n d e - o l i v i n e * 2V determined universal  are regular,  Some d i o p s i d e - o l i v i n e  and show e x t e n s i v e c o r r o s i o n o r a l t e r a t i o n as boundaries.  on the u n i v e r s a l s t a g e , compositions  stage.  Olivine i s cut  "church-window"  between o l i v i n e s and orthopyroxenes  e s p e c i a l l y when o l i v i n e i s e n c l o s e d i n b r o n z i t e . are ragged  The  *  x  boundaries  i s present  from Fo80 t o Fo86  w i t h t h e m a j o r i t y r a n g i n g from Fo84-86, (2V =89±2 ) .  Boundaries  tend  clinopyroxenes.  o  by s e r p e n t i n e - m a g n e t i t e  from  appear to be by l a t e  O l i v i n e i n a l l r o c k s has a range o f c o m p o s i t i o n  o l i v i n e i s found  fine  grains.  t e x t u r e s a r e s u g g e s t i v e o f magmatic o r i g i n .  f o r m a t i o n of l a r g e p o i k i l i t i c  texture.  grains  t e x t u r e s a r e common e s p e c i a l l y w i t h o l i v i n e and pyroxene-  e u h e d r a l to a n h e d r a l . to  Feld-  A l l m i n e r a l s e x c e p t o l i v i n e o c c u r as p o i k i l i t i c  and a l l m i n e r a l s e x c e p t hornblende Cumulus-like  i n the 3050 c r o s s - c u t c o n t a i n  from probe and  F i g . 5.  F i g . 6.  Sharp c o n t a c t o f n o r i t e w i t h n o r i t e a t top.  pyroxenite,  Complex age r e l a t i o n s h i p of n o r i t e to u l t r a b a s i c r o c k s . Note hornblende p y r o x e n i t e i n c l u s i o n i n n o r i t e at hammer. A l s o top c e n t e r and c e n t e r shows p y r o x e n i t e fragments i n h o r n blende pyroxenite.  Fig.  8.  Cumulus-like o l i v i n e s i n p o i k i l i t i c o f hornblende . X10, p l a i n l i g h t .  grain  Fig.  9.  C u m u l u s - l i k e orthopyroxenes i n p o i k i l i t i c h o r n b l e n d e . X10, p l a i n l i g h t .  Orthopyroxene  (En75 - 85)  i s the main c o n s t i t u e n t o f the p y r o -  x e n i t e s and the p r i n c i p a l pyroxene Many g r a i n s show s c h i l l e r of  i n t h i s area o f the u l t r a m a f i t e .  s t r u c t u r e w i t h e x s o l v e d l a m e l l a e and p a t c h e s  clinopyroxene along cleavage traces.  Many g r a i n s show a z o n i n g  i l l u s t r a t e d by a s l i g h t v a r i a t i o n i n 2V from r i m t o c o r e . clinopyroxene or hornblende pyroxene,  Occasionally,  form j a c k e t s around o r t h o p y r o x e n e s .  Ortho-  a l t h o u g h much o f i t i s a i n t e r l o c k i n g mosaic o f g r a i n s , may  poikilitically  e n c l o s e o l i v i n e and may be e n c l o s e d by a l l o t h e r m i n e r a l s .  Clinopyroxene, m o s t l y d i o p s i d e  (determined by m i c r o p r o b e ) has a  wide range o f c o m p o s i t i o n from Mg (44-53), Ca (40-48), and Fe (6-11), (Fig.  3 2 ) , and i s p r e s e n t i n most p y r o x e n i t e and some p e r i d o t i t e .  Most  d i o p s i d e i s m o t t l e d by h o r n b l e n d e and shows a g r e a t degree o f replacement *  Composition determined by probe and u n i v e r s a l s t a g e .  20  by i t .  Clinopyroxene  poikilitically  i s a n h e d r a l and i n t e r g r a n u l a r b u t much of i t  e n c l o s e s b r o n z i t e and, i n a few r o c k s ,  Common hornblende T e x t u r a l l y i t ranges to l a r g e p o i k i l i t i c  olivine.  i n the u l t r a b a s i c r o c k s i s brown to o l i v e  from m o t t l e d replacement  patches,  green.  interstitial  g r a i n s e n c l o s i n g a l l types o f p r i m a r y  silicates  including rare plagioclase grains. P l a g i o c l a s e i n the u l t r a b a s i c r o c k s and the h o r n b l e n d i t e s h a s a composition stitial, never  of An80-90,  a r e found  (bytownite).  These g r a i n s , g e n e r a l l y i n t e r -  i n a few p y r o x e n i t e s and most h o r n b l e n d i t e s b u t  i n o l i v i n e - b e a r i n g rocks. A c c e s s o r y m i n e r a l s a r e chromite  as e u h e d r a l p r i m a r y  and magnetite  grains within s i l i c a t e s .  Alteration  common i n the u l t r a m a f i c r o c k s a r e p h l o g o p i t e a f t e r chlorite,  talc, actinolite-tremolite,  p h y l l i t e , and  (11)  which both  products  hornblende,  s e r p e n t i n e , magnetite,  antho-  carbonates.  Pyroxenite  The most common p y r o x e n i t e i s a w e b s t e r i t e , a medium dark brown rock composed of two pyroxenes, Although  occur  the orthorhombic  grained,  b r o n z i t e and d i o p s i d e .  pyroxene i s t h e more abundant, some r o c k s  c o n t a i n a g r e a t e r p r o p o r t i o n of c l i n o p y r o x e n e .  Websterites  predominate  from about 6400N. i n the c r o s s - c u t to the south s i d e ( f o o t w a l l ) o f the Climax  ore zone ( F i g . 37 and App. 1).  p r e s e n t up to 5% i n a l l the p y r o x e n i t e s . but may  reach  2-3% i n some r o c k s .  I n t h i s a r e a hornbleride i s P l a g i o c l a s e i s very rare  W e b s t e r i t e s n o r t h of 7560N. and p a r t i c u l a r l y 8000N., which occur as b o d i e s map  those  north, o f  too s m a l l to be shown p r o p e r l y on a  tend to be . r i c h i n hornblende.  As  the s o u t h e a s t  edge of the Chinaman  ore zone i s approached hornblende w e b s t e r i t e s become d e f i c i e n t clinopyroxene  to the p o i n t where they a r e c l a s s e d as  Pyroxenite increases.  grades to p e r i d o t i t e  in  orthopyroxenites.  as the p r o p o r t i o n of  olivine  Minor o l i v i n e i s p r e s e n t i n p y r o x e n i t e s f o r a d i s t a n c e o f  about 50' on  the south  ( f o o t w a l l ) s i d e of the Climax orebody.  orebody the o l i v i n e c o n t e n t i n the r o c k s i n c r e a s e s and an o l i v i n e p y r o x e n i t e .  At  the  the r o c k i s  Near the n o r t h edge of the C l i m a x o r e zone  the r o c k becomes p e r i o d o t i t i c . changes a b r u p t l y , p r o d u c i n g  In some p l a c e s the o l i v i n e  sharp  content  c o n t a c t s as a t 7260N. , ( F i g . 10)  where the r o c k changes from a w e b s t e r i t e to an o l i v i n e  pyroxenite.  In most i n s t a n c e s i n the more n o r t h e r l y s e c t i o n s o f the 3050 c r o s s cut,  o l i v i n e p y r o x e n i t e s are m o d i f i e d by abundant h o r n b l e n d e ,  uently  poikilitic.  (Ill)  Peridotite  Peridotite  shows a wide range o f appearance depending upon  m i n e r a l s p r e s e n t and such  the degree of a l t e r a t i o n .  the  Fresh harzburgites  as those on the hanging w a l l of the Climax orebody a r e dense,  h a r d , b l a c k r o c k s c o n t a i n i n g orthopyroxene f l a s h y , b l a c k , dense r o c k s found cut  freq-  and o l i v i n e .  Poikilitic,  i n the n o r t h e r n p a r t of the c r o s s -  are h o r n b l e n d e - p e r i d o t i t e s c o n t a i n i n g o r t h o p y r o x e n e ,  minor  clino-  pyroxene, hornblende and o l i v i n e .  J u s t n o r t h of the C l i m a x orebody  f o r a d i s t a n c e of perhaps 300  the r o c k i s green,  and  crumbles i n the hand.  feet  s o f t and  altered  22  I n such r o c k s , many o f the pyroxenes have been a l t e r e d to hornblende and l a r g e p l a t e s o f p h l o g o p i t e have formed around grains  ( F i g . 11).  I n these r o c k s o l i v i n e shows some s e r p e n t i n i z a t i o n  w i t h abundant m a g n e t i t e t r a i n s b u t i s s t i l l itization  cut.  Ural-  of phlogopite.  Hornblendite  Hornblendite pegmatitic  remarkably f r e s h .  o f pyroxene i s common and c h l o r i t e forms on the ragged  edges and b o u n d a r i e s  (IV)  olivine  o c c u r s as dykes o r v e i n s and as l a r g e c l o t s o r  zones e s p e c i a l l y i n t h e n o r t h e r n Chinaman a r e a o f the c r o s s -  F i n e - g r a i n e d , dense, b l a c k dykes o r v e i n s from a few mm. t o  5-10 cm. c u t a l l rock u n i t s and o r e zones on the 3050 l e v e l . have v e r y  sharp  contacts.  p r i s m a t i c hornblende w i t h townite  i n composition),  They a r e composed o f a l i g n e d interstitial  p l a g i o c l a s e up to 10% (by-  ( F i g . 12). L a r g e r ,  coarser grained,  i r r e g u l a r , d i s c o n t i n u o u s hornblende dykes o c c u r m a i n l y zones (which a r e  They  d e s c r i b e d  very  i n protoclastic  l a t e r ) south o f the Chinaman orebody,  some showing a r e a c t i o n margin ( F i g . 13). They appear t o i n c o r p o r a t e o r form the h o s t f o r b r e c c i a fragments o f u l t r a b a s i c and n o r i t e and d i o r i t e r o c k s ; they a l s o t r a v e r s e such i n c l u s i o n s and appear a s inclusions  themselves.  E a s t o f the Chinaman zone l a r g e c l o t s o f c o a r s e - g r a i n e d blende-plagioclase pegmatitic material i s present.  horn-  Hornblende "•  c r y s t a l s s e v e r a l i n c h e s l o n g a r e cemented by i n t e r s t i t i a l p l a g i o c l a s e and minor q u a r t z . the p y r o x e n i t e s  T h i s zone i s a p o s s i b l e r e a c t i o n m a r g i n between  on the e a s t edge o f t h e Chinaman orebody and an  a d j a c e n t n o r i t e r e v e a l e d by d r i l l i n g  to the immediate  east.  Fig.  11.  O l i v i n e g r a i n s i n hornblende. Top r i g h t c e n t e r , p h l o g o p i t e a f t e r hornblende w i t h incipient chlorite alteration. Right side Orthopyroxene u n a l t e r e d . 10X, p l a i n l i g h t  Fig.  12.  F i g . 13.  A f i n e g r a i n e d h o r n b l e n d i t e dyke c u t t i n g a n o t h e r h o r n b l e n d i t e dyke and h o s t u l t r a b a s i c rocks  One f o o t wide h o r n b l e n d i t e dyke w i t h r e a c t i o n m a r g i n . P r o t o c l a s t i c area on s o u t h s i d e o f Chinaman ore zone.  MINERALIZATION AND OREBODIES  Introduction S u l f i d e m i n e r a l s on the 3050 l e v e l c r o s s - c u t o c c u r as d i s seminated g r a i n s , as v e i n l e t s and s c h l i e r e n , and as massive all  e x c l u s i v e l y i n u l t r a b a s i c rocks.  The m i n e r a l o g y  clots  i s simple,  c o n s i s t i n g o f p y r r h o t i t e , p e n t l a n d i t e , c h a l c o p y r i t e , m a g n e t i t e and v e r y minor p y r i t e .  Early investigators tentantively  identified  o t h e r N i - b e a r i n g s u l f i d e s b u t none was seen i n t h i s a r e a o f the mine Some secondary limonite,  o r supergene m i n e r a l s , c h a l c o c i t e , c o v e l l i t e and  coat s u r f a c e s on exposed, weathered, s u l f i d e - b e a r i n g rock  but a r e ; l o s t during p r e p a r a t i o n o f p o l i s h e d s e c t i o n s .  Disseminated  Sulfides  A l l u l t r a b a s i c r o c k u n i t s w i t h i n t h i s a r e a o f t h e mine c o n t a i n the t h r e e p r i n c i p a l s u l f i d e s as s i n g u l a r o r composite,  xenomorphic  b l e b s and i n t e r s t i t i a l  to s u b h e d r a l  f i l l i n g s between f r e s h e u h e d r a l  g r a i n s o f o l i v i n e , orthopyroxene (Fig.  14).  I n many specimens these  s i m i l a r t o those o c c u p i e d blende,  and i n some p l a c e s  s u l f i d e s occupy p o s i t i o n s  i n o t h e r specimens by i n t e r s t i t i a l  and may be r e p l a c e d by hornblende,  magmatic r e a c t i o n .  clinopyroxene  The o c c u r r e n c e  p o s s i b l e as a l a t e  hornstage  o f the s u l f i d e s i n ultramafi'c  r o c k s resembles t h a t o f primary . c r y s t a l l i z a t i o n f r o m an i m m i s c i b l e s u l f i d e phase.  T h i s resemblance i s enhanced by the p r e s e n c e o f  rounded o r v e r m i c u l a r b l e b s o f the s u l f i d e e n c l o s e d i n u n a l t e r e d  I mm.  Fig.  14.  I n t e r s t i t i a l po.-pn.-cpy. g r a i n s i n f r e s h pyroxenite. XI6, p l a i n l i g h t .  Composite po.-cpy. bleb and magnetite g r a i n enclosed i n o l i v i n e . X63, p l a i n l i g h t .  27  ' o l i v i n e and o r t h o p y r o x e n e  g r a i n s ( F i g . 15).  The  chemical  compositions  o f the a c c e s s o r y p y r r h o t i t e and p e n t l a n d i t e are v a r i a b l e and directly  related  to the l i t h o l o g i c a l u n i t t h a t c o n t a i n s them, as  expanded upon i n the f o l l o w i n g s e c t i o n . appears  i n the  The  sulfide  component  to undergo a b u l k c o m p o s i t i o n a l change from Cu- and  composite  appear  aggregates  i n p y r o x e n i t e s to more Cu- and N i - p o o r  Ni-rich aggregates  peridotites.  Net-Textured  Sulfides  N e t - t e x t u r e can be c o n s i d e r e d an e x t e n s i o n of the d i s s e m i n a t e d type where the s u l f i d e s expand to form a n e a r l y c o n t i n u o u s between s i l i c a t e s ,  forming an i n t e r c o n n e c t e d , l a c y  net  texture.  The  s i l i c a t e s , p a r t i c u l a r l y o l i v i n e and b r o n z i t e , a r e more e u h e d r a l  than  i n the d i s s e m i n a t e d t y p e , f o r m i n g u n a l t e r e d i s o l a t e d c r y s t a l s i n a a l l o t r i o m o r p h i c s u l f i d e groundmass.  The  i n the same manner as the hornblende  in poikilitic  p y r o x e n i t e s and p e r i d o t i t e s The n e t - t e x t u r e i s seen  s u l f i d e s here appear to o c c u r hornblende  ( F i g . 16). to o c c u r i n weakly m i n e r a l i z e d a r e a s  of the c r o s s - c u t , m a i n l y i n p y r o x e n i t e s , b u t a r e b e s t and  seen i n the low grade  In p a r t i c u l a r ,  developed  s e c t i o n s of the Climax and Chinaman ore  the n e t t e x t u r e , i s w e l l developed  i n the  hanging  w a l l p a r t o f the Climax orebody where o l i v i n e predominates c r y s t a l s and a l s o i n the core o f the Chinaman ore zone.  as e u h e d r a l  That  these  s u l f i d i c n e t - t e x t u r e d p e r i d o t i t e s can be mined e c o n o m i c a l l y i s due i n p a r t to t h e i r p r o x i m i t y to more massive  sulfides.  zones.  Massive  Sulfides  Massive s u l f i d e s  form most o f the o r e .  The s u l f i d e s  form a  c o n t i n u o u s a n h e d r a l groundmass commonly up to 50% of the m a t e r i a l present  ( F i g . 17).  Gangue m i n e r a l s c o n s i s t  o l i v i n e and pyroxene which appear mass.  These  c r y s t a l s are l a r g e r  found i n l e s s massive o r e s .  of e u h e d r a l c r y s t a l s o f  to " f l o a t " i n the s u l f i d e and b e t t e r developed  In the Chinaman orebody,  ground-  than those which i s , ,  more h o r n b l e n d i c , l a r g e c r y s t a l s of h o r n b l e n d e , a p p a r e n t l y p r i m a r y crystals,are  e n c l o s e d by massive  Some s i l i c a t e complete  c r y s t a l s show c o r r o s i o n , and p a r t i a l to almost  replacement.  embayments and  sulfides.  Such f e a t u r e s as replacement a l o n g c l e a v a g e s  sketetal  remains may  be a s c r i b e d  to  selective  replacement, l a t e magmatic r e a c t i o n s o r b o t h . Massive o r e s , p a r t i c u l a r l y i n the Chinaman zone seem to have been m o d i f i e d by l a t e stage movements of the s u l f i d e m i n e r a l s producing a p r o t o c l a s t i c  t e x t u r e ( F i g . 18).  Fragments o f d i s -  seminated and n e t - t e x t u r e d m a t e r i a l have been i n c o r p o r a t e d the massive stringers sulfide  sulfides.  into  These fragments a r e rimmed by massive  and i n some i n s t a n c e s appear f r a c t u r e d  sulfid  and r e h e a l e d by  stringers.  The p r o t o c l a s t i c  t e x t u r e l e d Aho  (1956) to suggest a p o s s i b l e  h y d r o t h e r m a l o r i g i n f o r the ore m i n e r a l s .  On  the o t h e r hand,  s c a t t e r e d anhedral grains t y p i c a l of primary a c c e s s o r i e s , euhedral s i l i c a t e s f l o a t i n g i n a groundmass o f s u l f i d e and v e r m i c u l a r blebs of s u l f i d e s  e n c l o s e d i n pyroxenes, ' o l i v i n e s and e a r l y  b l e n d e s u p p o r t a magmatic o r i g i n f o r the ore m i n e r a l s .  horn-  Fig.  17.  Massive s u l f i d e s w i t h e u h e d r a l floating". X60, p l a i n l i g h t .  silicates  Fig.  18.  Protoclastic  t e x t u r e o f Chinaman o r e ,  fragments of d i s s e m i n a t e d and n e t - t e x t u r e d ore w i t h s u l f i d e s c h l i e r e n a n d f r a c t u r e f i l l i by s u l f i d e s .  s e p a r a t e d from p y r r h o t i t e by X63, plain light  pentlandite.  31  Te.xtural R e l a t i o n s  Between t h e V a r i o u s  Sulfides  Disseminated to massive, p y r r h o t i t e , p e n t l a n d i t e ,  and c h a l -  c o p y r i t e a r e a l l p r e s e n t i n ore samples and have r o u g h l y proportions, the  least.  constant  w i t h p y r r h o t i t e the most abundant and c h a l c o p y r i t e This proportion  appears to be 70:20:10.  Pyrrhotite  forms an i r r e g u l a r , medium- to f i n e - g r a i n e d mosaic o f composite anhedral grains.  Pentlandite  u s u a l l y occurs a t p y r r h o t i t e  grain  b o u n d a r i e s , as does c h a l c o p y r i t e , as medium- to f i n e - g r a i n e d and be  composite masses.  s e p a r a t e d from p y r r h o t i t e by p e n t l a n d i t e  instances and  I n some specimens, c h a l c o p y r i t e  pentlandite  anhedra  i s seen t o  ( F i g . 19).  o c c u r s as i r r e g u l a r b l e b s w i t h i n  I n some pyrrhotite,  c h a l c o p y r i t e appears as c r o s s - c u t t i n g l a t h s i n p y r r h o t i t e .  D i s c o n t i n u o u s aggregates o f p y r r h o t i t e may be connected by p e n t l a n d i t e and c h a l c o p y r i t e . extent pentlandite  Chalcopyrite  and p y r r h o t i t e form as c r o s s - c u t t i n g  or replacements i n f r a c t u r e d s i l i c a t e s , remobilization  p r i n c i p a l l y and to a l e s s e r  ( F i g . 2 0 ) , s u g g e s t i n g some  o f the s u l f i d e s ( F i g . 24).  Chalcopyrite  seen to c u t the o t h e r s u l f i d e s , m a i n l y p e n t l a n d i t e . and  infrequently  and  e x s o l u t i o n - l i k e textures  copyrite, this  chalcopyrite  texture  fillings  a r e seen to form l a t h s , i n pyrrhotite.  i s usually restricted  i s also  Pentlandite flame-like  I n the case o f c h a l to v e r y s m a l l , i s o l a t e d ,  composite s u l f i d e aggregates i n b a r r e n r o c k .  ,  Paragenesis The  Cu-Ni-Fe-S m i n e r a l assemblage seen a t G i a n t  those seen a t most n i c k e l i f e r o u s . p y r r h o t i t e d e p o s i t s .  Mascot a r e Most o r e b o d i e s  F i g . 20. Chalcopyrite r e p l a c i n g f r a c t u r e s i n s i l i c a t e . X160, p l a i n l i g h t .  of t h i s type are accepted as being magmatic i n o r i g i n ( C r a i g and K u l l e r u d , 1969) and are formed through unmixing, e x s o l u t i o n and r e e q u i l i b r a t i o n by slow c o o l i n g from a monosulfide s o l i d s o l u t i o n . K u l l e r u d , Yund and Moh (1969), and Craig and K u l l e r u d (1969), have made extensive reviews o f the phase r e l a t i o n s i n the various systems and the quarternary  ternary  system containing Cu-Ni-Fe-S and have  o f f e r e d s e v e r a l s t a b l e isothermal mineral assemblages i n the temperature ranges from above 1000°C to below 550°C.  The paragenetic  sequence seen at the Chinaman and Climax orebodies w i l l be i n t e r p r e t e d i n the l i g h t of these s t u d i e s . The average bulk composition of the Giant Mascot ores are b e l i e v e d to l i e w i t h i n the s i n g l e phase region of the monosulfide s o l i d s o l u t i o n  (Mss) a t  1000UC  approximated by (1956)  Muir  as i l l u s t r a t e d  i n figure 2 1 .  T h i s c o m p o s i t i o n was.  the use o f s u l f i d e a n a l y s e s of Horwood ( 1 9 3 7 ) ,  (1971)  and e s t i m a t e s of p y r r h o t i t e - p e n t l a n d i t e - c h a l -  c o p y r i t e p r o p o r t i o n s by the p r e s e n t a u t h o r .  As  these p l o t s are a l l  v e r y s i m i l a r t o t h a t c o m p o s i t i o n a s s i g n e d to Sudbury, the Sudbury  Aho  figure i s plotted.  (1962),  Hawley  V a r i a t i o n s from the Sudbury  bulk  c o m p o s i t i o n s w i l l a c c o u n t f o r i n d i v i d u a l p a r a g e n e t i c sequences assemblages.  s  FIG. 21. Schematic 1,000° C isothermal d i a g r a m of the C u - . F e - X i - S system in the presence of vapor. T i e lines to S l i q u i d are omitted for c l a r i t y . N o t e the wide extent of the homogeneous sulfide liquid (stippled) and the large r e g i o n of liquid i r n m i s c i b i l i t y (sulfur l i q u i d and sulfide l i q u i d ) . T h e M s s n e a r l y spans the F e - X i - S face of the system. P o i n t s designated A and B are discussed i n the text.  and  34  The l i q u i d u s  temperature may  be as low as 1000 C a t which U  a pyrrhotitic nickel-bearing liquid w i t h a c o p p e r - r i c h l i q u i d , phase B.  (Mss, F i g . 21) phase A  coexists  Upon c o o l i n g a t some temperature  above 850°C i t i s p o s s i b l e f o r a c o p p e r - e n r i c h e d l i q u i d from the Mss  point  to s e g r e g a t e  and form two s u l f i d e phases, a N i - p y r r h o t i t e  s o l u t i o n and a c h a l c o p y r i t e s o l i d s o l u t i o n  (Cpss).  solid  T h i s mechanism  may  account f o r the c h a l c o p y r i t e r i c h s e g r e g a t i o n s and v e i n i n g seen a t G i a n t Mascot (Fig.  and many o t h e r Cu-Ni  deposits related  to u l t r a b a s i c rocks  22). In g e n e r a l the b u l k c o m p o s i t i o n s of Ni-Cu s u l f i d e o r e s commonly l i e  w i t h i n the q u a t e r n a r y Mss. down to 500°C.  P y r i t e may  form i n some q u a t -  e r n a r y systems a t temperatures of 743°C where t i e l i n e s a r e e s t a b l i s h e d between Cpss and p y r i t e .  T h i s i s v e r y s u l f u r dependant  decrease i n s u l f u r w i l l prevent p y r i t e formation. below 600°C a c h a l c o p y r i t e and/or p e n t l a n d i t e Mss  and a s m a l l  A t some temperature  ( s s ) can e x s o l v e from the  and w i l l c o n t i n u e to do t h i s as the temperature i s lowered and  p y r r h o t i t i c Mss becomes d e p l e t e d i n N i and Cu. the Mss  can o n l y accomodate  1% Cu but may  In most c a s e s as a t G i a n t Mascot  A t temperatures o f  down i n t o two  c u b i c phases  the e x s o l u t i o n temperature f o r p e n t l a n d i t e  A t temperatures o f 590°C  ( c h a l o c p y r i t e and c u b a n i t e ) .  Cpss w i l l  t h i s m i n e r a l p a i r f o r m i n g i n N i - p o o r assemblages,  c h a l c o p y r i t e and p y r r h o t i t e . is  break-  that* below  r e a c t s to form  A more l i k e l y e x p l a n a t i o n of t h e i r  t h a t a t G i a n t Mascot, where 5% o r more N i i s p r e s e n t , Cpss and  i f e r o u s p y r r h o t i t e Mss  that  The absence o f  c u b a n i t e and s c a r c i t y o f p y r i t e can be e x p l a i n e d by the f a c t 334°C  500°C  c o n t a i n g r e a t e r than 5% N i .  i s c o n s i d e r a b l y lower than 600°C and p e n t l a n d i t e f o r m a t i o n f o l l o w s o f c h a l c o p y r i t e from the Mss.  the  can c o e x i s t and no c u b a n i t e - p y r i t e  absence nickel-  assemblage  35  36  i s formed.  Ac very low temperatures, c o n s i d e r a b l y below 300 C, the.Mss U  breaks down to an assemblage.of p y r r h o t i t e and p e n t l a n d i t e - p y r i t e . Relations  i n v o l v i n g the f o r m a t i o n  o f p e n t l a n d i t e ' - p y r i t e are n o t c l e a r .  The minor p y r i t e seen a t Giant Mascot appears as l a t e stage v e i n i n g o r intergrowths  with pentlandite.  I n f i g u r e 23 the common assemblages a t  low temperatures o b s e r v e d i n most massive N i - C u ores which i n c l u d e those of G i a n t Mascot a r e shown. s  Kk.,7.3.  Low  i!»iu[)«.T;tiur>; m i n e r a l  aiMenib.lage* in  w h e r e a s r!jv»e  X i ' - C i ! ores. '•wMiswrn a r e  The  must v.tmiuvm a . - ' - o c i a u o i i s a r e i n d i c a t e d  i;»ti;t—ttttl b y <tt.--h?d l i n e s .  by •  *o\'ul l i n e s  37  In summary the p a r a g e n e s i s and m i n e r a l assemblages n o t e d a t G i a n t Mascot a r e w e l l documented by l a b o r a t o r y e x p e r i m e n t a l w o r k e r s . illustration at  of the sequence o f f o r m a t i o n of s i l i c a t e s  G i a n t Mascot i s shown i n f i g u r e 24.  Apparent P a r a g e n e s i s  An  and s u l f i d e  phases  •  Fig.  24  Time Approximate  Temperatures  Chromite Magnetite  . .  Olivine 1000°C  O/pxn C/pxn Pyrrhotite Plagioclase Chalcopyrite  (1)  850°C  Hornblende Chalcopyrite Pentlandite Pyrite  (2)  600°C 400°C < 300°C  Climax Orebody The  Climax orebody, c r u d e l y c y l i n d r i c a l ,  i n t e r s e c t e d by the 3050  l e v e l c r o s s - c u t a t 6900N., see map, Appendix 1, has maximum dimensions o f 90 x 50 f e e t i n p l a n .  The m i n e r a l i z e d zone plunges  30° W. d i r e c t i o n w i t h a v e r t i c a l l e n g t h o f almost a t the 2700 f o o t  a t 63° i n a N.  600 f e e t ,  terminating  level.  The o r e zone o c c u r s a t the c o n t a c t between p e r i d o t i t e w a l l ) and p y r o x e n i t e .  (hanging  The p y r o x e n i t e on the south s i d e o f t h e o r e zone  i s w e b s t e r i t e w i t h minor o l i v i n e and becomes more b r o n z i t i c and o l i v i n e r i c h i n the h i g h grade a r e a . p e r i d o t i t e i s sharp the o r e m i n e r a l s .  The c o n t a c t between the p y r o x e n i t e and  and corresponds  I n g e n e r a l , the w a l l r o c k s o f t h e C l i m a x o r e zone  range from p e r i d o t i t e through on  to t e x t u r a l and t e n o r changes i n  t h e w e s t e r n edge.  p y r o x e n i t e to n o r i t e which i s p r e s e n t  T h i s orebody c o r r e s p o n d s  t o Aho's massive  type,  an o r e zone a t o r n e a r the c o n t a c t between two r o c k u n i t s w i t h no zonal d i s t r i b u t i o n o f l i t h o l o g i c a l o r ore u n i t s . 2, f o r the g e n e r a l geology  See Map 1, Appendix  o f t h e Climax a r e a .  O l i v i n e and pyroxene i n the o r e zone show d e f o r m a t i o n a l as e v i d e n c e d  by t w i n n i n g and u n d u l a t o r y  such as d r a g f o l d s , banding (1956) as c r i t e r i a  and m a r g i n a l  extinction.  strain  Other features  f l o w l i n e s as c i t e d by Aho  f o r what he c a l l e d , "massive, i n j e c t i o n o r i g i n  ore",  a r e n o t r e p o r t e d a t t h e Climax body. The apparent  t e n o r o f t h e orebody appears to change v e r t i c a l l y w i t h an maximum N i and Cu c o n t e n t  ompanied by a low r a t i o o f Ni/Cu. o f r i n g d r i l l i n g assay  a t t h e 3108 f o o t e l e v a t i o n a c c T h i s i s deduced from  calculations  t e s t s on t h r e e l e v e l s and t h e o v e r a l l grade and  39  tonnage of  the orebody as  illustrated  i n Table  1.  Table 1 Climax Ore  Calculations Ni/Cu  Cu.%  Ni%  Tons/vert.ft.  Elev. 3198  446  1.01  .38  2.66  3108  435  1.33  .66  2.00  2959  414  1.08  .43  2.51  0.78  0.36  Average of b l o c k between 3298 and and 2700  / ,  353  2. 16  T o t a l Tonnage = 211,000  On  the b a s i s o f  these somewhat i n c o m p l e t e d a t a i t can be  t h a t the orebody d e c r e a s e s i n s i z e and Z o n a t i o n of the ore m i n e r a l s f i g u r e s 25,  26,  and  27, which are  are  show z o n a t i o n  seen to i n c r e a s e  c o r r e s p o n d i n g to the values  foot l e v e l .  Nickel  and contour  values  c o n c e n t r i c a l l y inward w i t h the h i g h e s t  grade zone  f o o t w a l l or  Copper  " t r o u g h " of the o r e p i p e . a high  shaped ore p l a n .  l e v e l s above and  grade zone i s n o t e d on .  This feature i s further r e f l e c t e d i n  the Cu/(Cu+Ni) p l o t which shows the h i g h e s t  near a l a r g e adjacent  Additional level  as w e l l are appended.  the w e s t e r n s i d e of the orebody.  i s n o t e d on  in  computer c o n t o u r p l o t s of N i , Cu  behave i n a s i m i l a r f a s h i o n but  o f the e l l i p t i c a l  plunge.  i s i l l u s t r a t e d remarkably w e l l  Cu/(Cu+Ni) r e s p e c t i v e l y a t the 3108 p l o t s which do not  N i grade down the  concluded  r a t i o on  the w e s t e r n  T h i s western b i a s of  below the 3108.  n o r i t e implying  The  side  mineralization  w e s t e r n boundary i s  some g e n e t i c l i n k between  mineral-  40  i z a t i o n o r l o c a l i z a t i o n of ore m i n e r a l s and n o r i t i c phases w i t h i n  the  ultramafite.  Chinaman Orebody The at  Chinaman orebody i s i n t e r s e c t e d i n the 3050 l e v e l c r o s s - c u t  8540N.  I t i s c r u d e l y e l l i p t i c a l and  plunge when viewed i n p l a n . a r e 90 x 100  of  two  The  i n the d i r e c t i o n o f  The maximum dimensions of  f e e t w i t h a v e r t i c a l e x t e n t o f 638'  2700 f o o t l e v e l . direction.  elongate  m i n e r a l i z e d zone p l u n g e s  the ore  zone  t e r m i n a t i n g a t the  a t 68  i n a N.  Above 3200 f e e t and below 2800 f e e t the o r e  o r t h r e e d i s c r e t e u n i t s which become s m a l l , low  60  W.  zone c o n s i s t s grade,  and much  faulted. The known b u t  r e l a t i o n s h i p of ore to the g e o l o g i c a l r o c k u n i t s i s not w e l l i t appears t h a t the core of the m i n e r a l i z e d zone i s a  grade to b a r r e n p e r i d o t i t e .  The  around p e r i d o t i t e and v e r t i c a l l y  ore zone forms a p a r t i a l  v e r y h o r n b l e n d e - r i c h phases. to be  The  f o o t w a l l , south and  east side,  mapping i s i n c o n c l u s i v e , s t u d y o f d r i l l suggest  by  appears  Further east,  n o r i t e , p o s s i b l y a l a r g e i n c l u s i o n , has been i n d i c a t e d by  c u s s i o n w i t h mine p e r s o n n e l  than  T h i s u n i t i s surrounded  a h o r n b l e n d i t e , p y r o x e n i t e , and n o r i t e b r e c c i a .  Although  envelope  i s d i s c o n t i n u o u s f o r m i n g more  one m i n e r a l zone i n h o r n b l e n d i c p y r o x e n i t e .  low  drilling.  l o g s and  dis-  t h a t t h i s orebody c o r r e s p o n d s  Aho's zoned type which he d e s c r i b e s as b e i n g zoned i n a  to  cylindrical  f a s h i o n around o r i n a p e r i d o t i t e c o r e w i t h o t h e r r o c k u n i t s c o n c e n t r ically ringing the  1900  the c o r e .  Specifically  t h i s orebody c l o s e l y  resembles  orebody which he d e s c r i b e d as "more complex, lower' i n grade,  aX  Ic  CL 3108 NI X' i 6340.Q  Eflofl.O  i CQOO.O  1 7000^0  CL 3108 c u ; 1 ^7020.0  1 7040.0  1 70CQ.0  1 7080.0  .—. 7100.0  g-j BQ40.0  1 E9C0.0  1  1  0080.0  1  7000.0  7020.0  — — i 7U'J3.0  1 7000.0  1 7CG0.0  1 7100.0  E-flXIS Fig.  25.  N i c o n t o u r p l o t o f Climax o r e a t 3108' elevation, i n percent.  Fig.  26.  Cu c o n t o u r p l o t o f Climax ore a t 3018' e l e v a t i o n , i n p e r c e n t .  js  42  6343.0  6S6O.0  F i g . 27.  lower i n r a t i o  Bssa.a  laco.a  7020  E-BXIS  a  73J0.Q  7Q60.0  7na].0  71S0.0  Cu/(Cu+-Ni) p l o t of Climax o r e a t 3108' e l e v a t i o n . Ratio i n percent.  of n i c k e l to copper and more h o r n b l e n d i c than the  o t h e r s , and i s more suggestive of replacement  origin."  The tenor of the Chinaman ore and the s i z e appear t o change e r r a t ically i n vertical direction.  This v a r i a t i o n can be a t t r i b u t e d to the  s t r u c t u r a l nature of the ore zones a t d i f f e r e n t e l e v a t i o n s . The l a r g a low grade s e c t i o n s , e s p e c i a l l y on the 3207 l e v e l , a r e r e a l l y t h r e e adjacent zones mined as one orebody, whereas three zones a r e d i s t i n g u i s h e d on the 3292 l e v e l and the grade i s higher but tonnage lower.  This kind  of s t r u c t u r e does not hold true i n the lower reaches o f the o r e zone.  C a l c u l a t i o n s from r i n g d r i l l i n g assay are i l l u s t r a t e d  i n the f o l l o w i n g T a b l e  the Chinaman orebody  r e s u l t s from 2.  Table 2 . Chinaman Ore C a l c u l a t i o n s Tons/vert.ft.  Elev.  Ni%  Cu%  Ni/Cu  3292  613  .67  .29  2.31  3207  945  .42  .16  2.63  3160  727  .61  .37  1.65  2802  432  .50  .21  2.38  Average o f b l o c k between 3338 and 2700  589  .73  .30  2.43  T o t a l Tonnage =376,000  Z o n a l f e a t u r e s of the o r e m i n e r a l s by element a r e p r e s e n t e d i n f i g u r e s 28,  29, and  30, which a r e computer drawn c o n t o u r p l o t s o f  i n f o r m a t i o n on the 3160 level  l e v e l o f N i . , Cu.,  and Cu/(Cu+Ni).  c o n t o u r p l o t s which do not i l l u s t r a t e  Both the N i and  The  plunge  to the  Cu/(Cu+Ni) r a t i o  also  h i g h e r here but i n g e n e r a l t h i s p l o t i s e r r a t i c and does n o t  s u p p o r t Aho, on  z o n a t i o n as w e l l are appended.  zoned h i g h e r grade p a r t s c o r r e s p o n d i n g  " t r o u g h " o r f o o t w a l l r e g i o n of the o r e zone. appears  Additional  Cu p l o t s show the e l o n g a t i o n i n the d i r e c t i o n of  w i t h the c o n c e n t r i c a l l y  assay  (1956), who  the p e r i p h e r y and  predicts  lower  t h a t the copper v a l u e s s h o u l d be h i g h e r  towards the core o f the o r e b o d y .  I t i s also  worth n o t i n g t h a t the b i a s of the h i g h e r grade m i n e r a l i z a t i o n i s towards the n o r i t i c r o c k s to the e a s t i n much the same manner as i n the Climax  body.  hi  These  two o r e b o d i e s which account f o r g r e a t e r than 10% o f the  t o t a l p r o d u c t i o n to the p r e s e n t time mined a t G i a n t Mascot c o r r e s p o n d to Aho's, (1956), two-type and zoned to  (Chinaman).  seem to  c l a s s i f i c a t i o n o f massive  (Climax)  A l t h o u g h he a s c r i b e s a magmatic i n j e c t i o n  origin  the former and a replacement o r i g i n to the l a t t e r i t i s b e l i e v e d  by  the w r i t e r , and t h i s s u b j e c t w i l l be expanded upon i n more d e t a i l later, "zoned"  t h a t b o t h types o f ore have magmatic i n j e c t i o n type b e i n g m o d i f i e d by l a t e r g e o l o g i c e v e n t s .  o r i g i n w i t h the  48  CHEMICAL ANALYSES OF SILICATES AND SULFIDES  Silicate Analytical Chemical  Techniques  a n a l y s e s o f s i l i c a t e m i n e r a l s were made withj^ARL  s c a n n i n g e l e c t r o n microprobe.  SEMQ  The probe was r u n a t 15 Kev. w i t h a  specimen c u r r e n t o f 25 to 30 n.A.  Sample i n f o r m a t i o n was g a t h e r e d  i n the "peak-seek" mode and output  c o l l e c t e d and r e f i n e d by t h e o n -  board  computer u s i n g Bence-Albee c o r r e c t i o n f a c t o r s .  The r e f i n e d  d a t a , i n weight p e r c e n t , a r e p r i n t e d o u t a t a t e l e t y p e t e r m i n a l . G r a i n s i n each rock specimen were a n a l y z e d u s i n g an i n c i d e n t beam a p p r o x i m a t e l y i n an attempt  10/-*••  i n diameter.  T h i s beam s i z e was s e l e c t e d  to a v o i d e x s o l u t i o n l a m a l l a e .  I n most i n s t a n c e s e l e m e n t a l  a n a l y s i s was b e l i e v e d good to ±1% o f the amount p e r c e n t , b u t i n the case of S i and Ca the e r r o r x<ras l a r g e r , p o s s i b l y g r e a t e r than ±2%. A t o t a l of 30 r o c k specimens y i e l d e d pyroxene and 13 o l i v i n e c o m p o s i t i o n s .  29 o r t h o p y r o x e n e ,  17 c l i n o -  I n most cases t h e a n a l y s e s were  made i n the c e n t r e of a g r a i n and 8 elements were determined.  Detailed  work on specimens o f a l l three m i n e r a l s was c a r r i e d o u t to determine homogeneity and to t e s t f o r the presence  o f a d d i t i o n a l elements.  A  complete t a b u l a t i o n o f a l l a n a l y s e s i n weight p e r c e n t and as mole f r a c t i o n s i s g i v e n i n Appendix 4.  Silicate  Analyses  F i g . 31, a p a r t o f the pyroxene q u a d r i l a t e r a l , chemical  compositions  i l l u s t r a t e s the  o f the pyroxenes and o f c o e x i s t i n g p a i r s .  pyroxenes range i n c o m p o s i t i o n  from En„  ,  to E n . 7C  l  n  Ortho-  and, c l i n o p y r o x e n e s  49  range from I f c ^ , . to W o ^ ^ ,  En^  g  O l i v i n e s , not plotted, range from F o  to E n  5  ori  n  5 2  ;  and F s ^  7 5  to Fo  oU.U  to  Fs^g.  . bO.O_>  T i e - l i n e s i n the pyroxene q u a d r i l a t e r a l show close p a r a l l e l i s m suggesting sound a n a l y t i c a l technique. bulk compositional changes. rock unit may  The s h i f t of the t i e - l i n e s indicates  Iron-enrichment  trends within a p a r t i c u l a r  define a zoning or c r y p t i c l a y e r i n g .  Elemental v a r i a t i o n plots of orthopyroxenes  along the 3050 cross-cut,  F i g . 32, show high Fe i n pyroxenites and corresponding low Fe i n p e r i d otites.  This i s p a r t i c u l a r l y well i l l u s t r a t e d at 7260N. where a small  pyroxenite unit shows a marked change i n orthopyroxene  composition when  compared to the large p e r i d o t i t e units that surround i t .  Although not  r e a d i l y apparent i n the i l l u s t r a t i o n , i n the Chinaman orebody and the brecciated footwall on the south, those orthopyroxenes high i n Fe are from pyroxenitic rocks and those with low Fe/ r a t i o s are found i n • • • . • Fe+Mg peridotites.  From the Climax orebody south, the elemental v a r i a t i o n  suggest a discrete change i n bulk composition and though not detectable megascopically the change might be considered evidence of heterogeneity within the pyroxenite. The Ca-variation appears sympathetic to Fe-variation i n the pyroxenite up to the l i t h o l o g i c a l boundary i n the Climax zone and again i n and near the Chinaman orebody. sympathetically with  In most other places Ca content v a r i e s  Mg.  An i l l u s t r a t i o n of elemental v a r i a t i o n i n clinopyroxenes, F i g . 33, i s included although paucity of data makes i n t e r p r e t a t i o n d i f f i c u l t . As i n the case of orthopyroxenes  Fe tends to be high when Mg i s low and  (Mg,Ca)Si0  3  s  QUADRILATERAL PLOT OF  '6//  ' / / //'// //  ft >'i if!  PYROXENE COMPOSITIONS 3050 CROSS-CUT  ///  , 11 ,!! M, jj 'iii' /// // ' * ///  '<'ifiSi ;, !  /'/ 1;; ;< 1111 'H 11 in 1  II  1  I  Mg  FIGURE3I 1 iii 1 // ,,  /  11  I'I  " I 'I  • .1  •21 MgSI0  JO  ~7~ 3  25 26 3C  80  (Mg.FeJSIO,  O  : a _ , Mg F e J  85  20  F I G U R E 32  75  104  At.%  /  ¥ 0—0  75  V O  n  i. 9 y  i  E L E M E N T A L VARIATION ORTHOPYROXENE 3050 CROSS-CUT Mg  I  (y  | PDT.  Fe  PXNITE.  Ca  V*/  10  O  HBLITE.  7  § oo  IN  CHINAMAN j  i  i  S SS ~1  J00 .  I I  NORITE  Mg F e J 50 15  Mg Fe. 40 5  At%  Mg Fe 50 15  E L E M E N T A L VARIATION  IN  CLINOPYROXENE 3050 CROSS-CUT Mg Fe Mg Fe 40 5  Ca — CHINAMAN t i  o o oo oo  I  I PDT.  I  | PXNITE.  I  | HBLITE,  .100'  I NORITE *•  1  Ln ro  53  v i c e - v e r s a , and t h i s r e l a t i o n s h i p i s dependant upon l i t h o l o g y .  Ca  g e n e r a l l y shows c l e a r i n v e r s e r e l a t i o n s h i p s w i t h Mg and i s sympathetic to Fe change except i n the Climax o r e zone. O l i v i n e , which i s n o t p l o t t e d , may be c o m p o s i t i o n a l l y r e l a t e d rock type.  I n the Climax orebody  olivine  to a  i n the f o o t w a l l p y r o x e n i t e  i s lower i n magnesium, Fo ., than t h a t i n the hanging w a l l  peridotite,  OH  Fo  oo  .  T h i s may be more apparent than r e a l due t o the u n c e r t a i n t y i n  analytical  error.  Sulfide Analytical  Techniques  Chemical a n a l y s e s o f s u l f i d e m i n e r a l s was made w i t h a J o e l microprobe a t the Department o f M e t a l l u r g y , U.B.C.  electron  T h i s probe uses a  20° t a k e - o f f a n g l e and was,run a t 25 Kev. and 0.8 m i l l i a m p s . i z a t i o n u s i n g pure m e t a l s t a n d a r d s i s done manually  Standard-  and output i s i n  d i g i t a l form as r e l a t i v e i n t e n s i t i e s of sample t o s t a n d a r d .  The  u n r e f i n e d d a t a i s then p r e p a r e d f o r computer c o r r e c t i o n s u s i n g the "MAJIC I I " program and r u n on the U.B.C, IBM 370 computer. c o r r e c t s f o r background,  T h i s program  dead time l o s s , a b s o r p t i o n e f f e c t s , f l u o r e s c e n c e  e f f e c t s and i o n i z a t i o n p e n e t r a t i o n l o s s e s .  I t i s b e l i e v e d t h a t the  r e s u l t s a r e q u a n t i t a t i v e l y a c c u r a t e to ±4% o f the element  present.  Twenty-nine samples were p r e p a r e d and a n a l y z e d , y i e l d i n g 29 p e n t l a n d i t e and 28 p y r r h o t i t e c o m p o s i t i o n s . Fe, N i , Cu, Co, and S by d i f f e r e n c e .  These m i n e r a l s were a n a l y z e d f o r A complete  t a b u l a t i o n o f these  a n a l y s e s i n weight p e r c e n t and atomic p e r c e n t i s shown i n Appendix 5.  S u l f i d e Analyses F i g . 34, i s a p a r t o f the Fe - N i - S e q u i l a t e r a l t r i a n g l e which shows the c h e m i c a l n a t u r e o f the p e n t l a n d i t e s and c o e x i s t i n g  pyrrhotites.  55  P e n t l a n d i t e e x h i b i t s a wide v a r i e t y of c o m p o s i t i o n s w i t h N i ^ ^ ^ to N i ^ g F e  29 0  t 0  d i t e , #7,  F e  40 7  a  n  d  S  32  1  t D  S  41  9  h t  y i e l d s a c o m p o s i t i o n of Fe^o  P y r r h o t i t e ranges  from F e _ c  c  ,  S.,  to 1.26  weight p e r c e n t .  c o m p o s i t i o n of F e  5 8 > g o  Ni  <  3  ?  P cent. e r  n>  N i  to Fe,-  c  A typical pental-  3 3 91' .., S.,  u J . /  4O.J  J J . J  N i up  S  w e i  C  o  l  86' 3 4  04'  S  and may  contain  J o . J  A t y p i c a l p y r r h o t i t e , #7,  yields  a  S^^.  T i e - l i n e s between the two m i n e r a l s are g e n e r a l l y p a r a l l e l from most s u l f u r - r i c h to s u l f u r - p o o r p a i r .  the  T h i s p r o b a b l y l e n d s credence  to  the a c c u r a c y o f a n a l y s i s and e q u i l i b r a t i o n between the m i n e r a l p a i r . The  s h i f t s i n the t i e - l i n e s i n d i c a t e a changing b u l k c o m p o s i t i o n of  s u l f i d e s and seem to be r e l a t e d t o the p e t r o l o g y of the r o c k u n i t s  the from  which the m i n e r a l s a r e d e r i v e d . I l l u s t r a t e d i n F i g . 35,  i s an e l e m e n t a l v a r i a t i o n p l o t of p e n t l -  a n d i t e a l o n g the 3050 c r o s s - c u t .  A p a t t e r n of p a r a l l e l Fe - N i v a r i a t i o n s  i s p r e s e n t i n the p y r o x e n i t e south o f the Climax  orebody and a g e n e r a l  i n c r e a s e i n the Fe - N i v a l u e i s p r e s e n t as the ore zone i s approached. Co c o n t e n t i s h i g h and i n the orebody.  i r r e g u l a r and  W i t h i n the Climax  and Co i s c o n s i s t e n t l y below 0.50  then drops d r a m a t i c a l l y near  zone N i v a l u e s are extremely atomic p e r c e n t .  The hanging  high wall  p e r i d o t i t e y i e l d s a p e n t l a n d i t e w i t h Fe v e r y h i g h and N i v e r y low. o v e r a l l r e s u l t appears  to be one  i d o t i t e except i n ore zones,  to those i n the Climax sympathetic i s t i c o f ore  The  and h i g h N i - F e p e n t l a n d i t e s i n p y r o x e n i t e s .  zones.  Chinaman zone p e n t l a n d i t e s behave  orebody.  Fe v a l u e s and  The  of F e - r i c h , Ni-poor p e n t l a n d i t e i n per-  Co v a l u e s a l s o appear h i g h e r i n the p e n t l a n d i t e s from p y r o x e n i t e s those from p e r i d o t i t e s .  and  These p e n t l a n d i t e s of h i g h N i  than  similarly content,  low Co c o n t e n t seem to be d i s t i n c t l y c h a r a c t e r -  F I G U R E 35  CLIMAX At %  o o  ... .  1  Fe Ni. 30  ELEMENTAL VARIATION IN PENTLANDITE 3050 CROSS-CUT Ni  PDT.  Fe  PXNITE.  Co 20  CHINAMAN J L  o CO  HBLITE. 100  NORITE  P y r r h o t i t e a n a l y s e s have not been p l o t t e d as they appear to have a random and narrow Fe spread a l o n g the c r o s s - c u t . t h e i r N i content i s g e n e r a l l y low and l a r g e c o r r e c t i o n suggest  questionable r e s u l t s .  amount o f Fe c o r r e s p o n d the two little  orebodies  factors  Three p y r r h o t i t e s w i t h the g r e a t e s t  to p e n t l a n d i t e s t h a t a r e F e - r i c h .  Within  the p y r r h o t i t e e x h i b i t s s i m i l a r Fe c o n t e n t s w i t h  fluctuation.  - E l e m e n t a l v a r i a t i o n s i n two  s i l i c a t e m i n e r a l s and one  m i n e r a l a l o n g the 3050 c r o s s - c u t c l e a r l y v a r y w i t h the l i t h o l o g i c a l u n i t s encountered and i n mineralogy  the o r e b o d i e s .  between r o c k u n i t s l i m i t s  f o r m a t i o n f o r the u l t r a b a s i c complex. later  Further,  section.  sulfide  different  The marked v a r i a t i o n  the p o s s i b l e mechanisms of These w i l l be d i s c u s s e d i n a  58  THERMAL HISTORY OF THE ULTRABASIC COMPLEX  Introduction Kretz,  (1961), demonstrated t h a t the d i s t r i b u t i o n  coefficient  2+ (Kp) r e l a t i n g Mg and Fe  d i s t r i b u t i o n between c o e x i s t i n g C a - r i c h and  Ca-poor pyroxenes d i f f e r s between magmatic ( K = 0.73) and metamorphic Q  (Kp = 0.57) assemblages.  The d i s t r i b u t i o n c o e f f i c i e n t i s dependant  upon temperature, p r e s s u r e and s o l i d s o l u t i o n c o n s t i t u e n t s o t h e r than 2+ Mg and Fe  .  Atkins,  (1969), however shows low  v a l u e s from c o -  e x i s t i n g pyroxene p a i r s c o l l e c t e d near the base o f the B u s h v e l d Complex (0.64 t o 0.70).  See F i g . 36.  These low v a l u e s a r e a t t r i b u t e d  m a i n l y to the g r e a t e r h y d r o s t a t i c p r e s s u r e under which were formed.  these pyroxenes  I n t h i s study t h e c h e m i c a l n a t u r e o f the pyroxenes  resembles c l o s e l y  those from s i m i l a r s t u d i e s on t h e Skaergaard (Brown,  1957), the S t i l l w a t e r  (Hess, 1960), and the B u s h v e l d ( A t k i n s ,  Wood and Banno, (1973), u s i n g an e m p i r i c a l approach,  1969).  derived  an e x p r e s s i o n f o r c a l c u l a t i n g e q u i l i b r a t i o n temperatures o f 2-pyroxene assemblages.  T h e i r method g i v e s temperatures f o r almost a l l exper-  i m e n t a l d a t a f o r multicomponent temperatures.  systems to w i t h i n ±60° C o f the observed  They s t r e s s t h a t t h i s e m p i r i c a l approach may l e a d t o  c o n s i d e r a b l e e r r o r o u t s i d e o f the t e m p e r a t u r e - c o m p o s i t i o n range c o v e r e d by the experiments used i n i t s d e r i v a t i o n s .  As the temperature  o f f o r m a t i o n and c o m p o s i t i o n o f the pyroxenes from G i a n t Mascot a r e b e l i e v e d c o m p a t i b l e w i t h those used i n Wood and Banno's study, the use o f t h e i r e x p r e s s i o n may be j u s t i f i e d .  Mg A N D Fe D I S T R I B U T I O N  COEFFICIENT  O F P Y R O X E N E S AT GIANT MASCOT  (K ) p  60  Methods The  v a l u e s were determined u s i n g the f o l l o w i n g e q u a t i o n ,  ( K r e t z 1961,  1963):  1-X° mg  x mg c  where  X  mg  c Xmg  and  =  ° Mg + Fe  r —  Mg  =  Mg + Fe  , i n orthopyroxene.  i n clinopyroxene.  2+  The e x p r e s s i o n f o r T ( i n ° K ) , Wood and Banno  1973:  -10202 cpx ln( Mg Si 0,) 2 2 6 opx aM g S i 0  T =  a  o  o  2  where a ^ „ . _ Mg Si 0  and  2  a° „. Mg Si 0  p X  Z  - 4.6  6  of e n s t a t i t e component i n c l i n o p y r o x e n e .  i s the a c t i v i t y o f e n s t a t i t e component i n orthopyroxene.  n  2  + 3.88(X° ) mg  6  p X  2  p x  i s the a c t i v i t y  p x  2  2  _ - 7.65X° mg  6  „ , „opx _ 2+ ana X = Fe mg — Fe + Mg  . i n orthopyroxene.  61  The a c t i v i t y a„, „. Mg Si 0  Ml M2 = X „ x X., , assumes the l a r g e i o n s Tig Tig  J  2  2  6  p r e s e n t i n the orthopyroxene s i t e s while The  and c l i n o p y r o x e n e s t r u c t u r e s occupy M2  the s m a l l e r o c t a h e d r a l l y c o o r d i n a t e d i o n s occupy M l .  i o n s have been a s s i g n e d t o t h e two s i t e s as f o l l o w s ; M2  Ml  Ca  Al *  2 +  3  « + Na  ~ 3+ Cr  Mn  Ti  2 +  4  +  Fe^ If  the occupancies  o f t h e two s i t e s by these i o n s a r e s u b t r a c t e d , 2+  the M2 and Ml s i t e s  t h a t remain a r e f i l l e d by Mg  a random d i s t r i b u t i o n . Mg Mg+Fe  '  (l-(Ca  2 +  + Na  +  + Mn  2 +  ))  and Fe  ions i n  becomes;  M 2  x _Mg___  2+  Cr * + T i 3  .  Thus a^, _. _  2+  .  (1-(A1  3 +  +  2+ Mg+Fe '  4  +  + Fe ")),,, Ml 34  F o r t h e purposes o f t h i s study a l l Fe was c o n s i d e r e d Fe  2+  2+ f o l l o w i n g Wood and Banno, (1973).  A l s o Mn  was n o t a n a l y z e d f o r i n  most pyroxenes b u t i s c o n s i d e r e d t o have an i n s i g n i f i c a n t e f f e c t on the c a l c u l a t e d  temperature.  G i a n t Mascot D i s t r i b u t i o n  Coefficients  Seventeen p a i r s o f C a - r i c h and Ca-poor c o e x i s t i n g pyroxenes were a n a l y z e d by e l e c t r o n microprobe. efficients  The r e s u l t i n g d i s t r i b u t i o n c o -  (Kp) a r e l i s t e d i n t h e r i g h t hand column o f t a b l e 3.  The  62 TEMPERATURE DATA OF COEXISTING PYROXENE PAIRS AND K VALUES. n  Sample No.  X  Fe  3  cpx En  a  opx En  TABLE 3.  T  °c c  K  D  1 = 26A  .186  .091  .598  1035  .788  2 = 28A-2  .190  .064  .600  975  .695  3 = 32A-1  .202  .025  .608  835*  .714  4 = 34A-1  .205  .096  .561  1035  7 = 43A-1  .187  .063  .615  970  .743  8 = 44A-1  .190  .058  .600  960  .670  9 = 46A-1  .170  .156  .630  1140*  .749  11 = 47A-1  .144  .053  .676  970  .720  15 = 82A-1  .214  .062  .587  950  .739  16 = 78A-1  .130  .106  .711  1090  .870*  17 =104A  .133  .088  .624  1005  .769  18 =106A  .159  .074  .668  1010  .755  19 =108A  .230  .074  .544  975  .781  .236  .076  .560  970  .780  .166  .082  .656  1020  .685  27 =152A-1  .224  .053  .559  925  .703  28 =156A-1  .211  .048  .587  915  .781  .620*  5 = 36A-3 6 = 41A-1  12 = 90A-1 13 = 92A-1 14 = 85A  20 -114A 21 =121A 22 =130A 23 =132A 24 =134A-2 25 =136A 26 =140A  29 =160A-2 30 =162A-1  *anomo!ous  63  v a l u e s range from 0.62  to 0.87  w i t h a mean o f 0.739.  I f the h i g h  and low v a l u e s a r e d i s c a r d e d the range i s more r e a s o n a b l e , (0.67 to 0.79), w i t h a mean o f 0.738. Fe-poor and F e - r i c h pyroxene  The h i g h and low  v a l u e s a r e from  p a i r s r e s p e c t i v e l y and  they a r e  anomalous w i t h r e g a r d to the r e m a i n i n g 15 p a i r s . The v a l u e of pyroxenes  o b t a i n e d from t h i s work suggests t h a t the  a r e magmatic.  A l t h o u g h t h i s v a l u e i s g r e a t e r than those o f  the B u s h v e l d i t i s r e a s o n a b l e to assume t h a t the h i g h p r e s s u r e o f f o r m a t i o n of B u s h v e l d pyroxenes K^,  (Atkins,  Skaergaard, higher  1969) .  (^Okm.) would r e s u l t i n a reduced  The v a l u e o b t a i n e d i s more l i k e  t h a t of the  (-*2km.) a l t h o u g h t h a t body appears to have formed a t a  temperature.  Pyroxene  Geothermometry  Of the 17 p a i r s o f pyroxenes s i m i l a r temperatures.  a n a l y z e d , 15 y i e l d  D i s r e g a r d i n g the h i g h and low v a l u e s , r e p r e s e n t i n g  pyroxenes extremely Ca-poor and C a - r i c h r e s p e c t i v e l y , temperatures c a l c u l a t e d f o r the G i a n t Mascot 1090° C.  remarkably  The mean o f the 15 temperatures  the range o f  U l t r a m a f i t e i s 915° C to  i s 990° C.  The  error  a c c o r d i n g to Wood and Banno s h o u l d be no g r e a t e r than ±60° C. A l l temperatures and p e r t i n e n t d a t a used i n the c a l c u l a t i o n s a r e l i s t e d i n t a b l e 3. a temperature  McTaggart,  ( p e r s . comm.), u s i n g the same methods  f o r a n o r i t i c r o c k a t the mine and o b t a i n e d a  calculated  temperature  of e q u i l i b r a t i o n o f 850° C. The a p p l i c a t i o n of the Wood and Banno, (1973), e x p r e s s i o n f o r the temperatures o f e q u i l i b r a t i o n o f c l i n o - and orthopyroxenes  yields  64  results  that  a r e remarkably c o n s i s t e n t  w i t h o t h e r igneous assemblages  (Bushveld, S k a e r g a a r d ) . There seems to be no c o r r e l a t i o n between the temperatures o f equilibration  (formation)and  values.  r o c k undoubtably has an e f f e c t on the between a p a r t i c u l a r is readily  seen.  The b u l k c o m p o s i t i o n of the and T v a l u e s b u t no  correlation  l i t h o l o g i c u n i t and a s e t of temperatures o f Those temperatures c a l c u l a t e d  from  olivine-bearing  r o c k s a r e s l i g h t l y h i g h e r o v e r a l l than those from p y r o x e n i t e s b u t a h i g h temperature from a p y r o x e n i t e p r o v i d e s the e x c e p t i o n to the r u l e .  65  RADIOMETRIC AGES  Hornblende, and where p o s s i b l e a b i o t i t e c o n c e n t r a t e was o b t a i n e d from the r o c k to be a n a l y z e d . poikilitic  In one case the hornblende o c c u r r e d as  g r a i n s e n c l o s i n g orthopyroxenes and no attempt was made to  s e p a r a t e them.  The c o n c e n t r a t e s were s u b s e q u e n t l y sent to the D e p a r t -  ment o f Geophysics a t U.B.C. to be dated by the K-Ar method.  U l t r a b a s i c Rocks Four samples c r o s s - c u t .(Fig« in  f o r r a d i o m e t r i c d a t i n g were c o l l e c t e d a l o n g the 3050  37).  They r e p r e s e n t f o u r d i f f e r e n t r o c k t y p e s , a l l r i c h  hornblende.  Sample 157A-1 was of  taken to r e p r e s e n t the m i n e r a l i z e d h o r n b l e n d i t e  the Chinaman orebody.  I t c o n s i s t s o f c o a r s e 1 to 2 cm.  hornblende w i t h i n t e r s t i t i a l l a n d i t e and c h a l c o p y r i t e . in  prismatic  and massive m i x t u r e s of p y r r h o t i t e , . pent-  The hornblende i s f r e s h m e g a s c o p i c a l l y but  t h i n - s e c t i o n some c h l o r i t e a l t e r a t i o n i s seen.  The  iron-nickel  f i d e s are penecontemporaneous w i t h h o r n b l e n d e , but c h a l c o p y r i t e to be l o c a l l y  l a t e r as i t f i l l s  sul-  appears  or r e h e a l s f r a c t u r e s i n hornblende  crystals. The apparent age o f c r y s t a l l i z a t i o n o f the hornblende y i e l d s age of 108 ± 4 m.y.  T h i s age i s a l s o the minimum age o f the main o r e  m i n e r a l s a l t h o u g h some c h a l c o p y r i t e i s younger  Sample 141A was  an  than hornblende.  c o l l e c t e d a p p r o x i m a t e l y 100 f e e t e a s t o f the  Chinaman orebody and i s a c o a r s e - g r a i n e d f e l d s p a t h i c h o r n b l e n d i t e . hand-specimen  i t appears as a f r e s h , almost p e g m a t i t i c r e a c t i o n r o c k  In  ORE BODIES  67  between the u l t r a b a s i c s and a n o r i t e . contain i n t e r s t i t i a l  plagioclase.  Coarse 1 to 2 cm.  Minor c h l o r i t e and  seen i n t h i n - s e c t i o n as a l t e r a t i o n m i n e r a l s and in  the p l a g i o c l a s e - r i c h The apparent  age  T h i s date suggests  hornblende  crystals  c a l c i t e are a l s o  some q u a r t z i s p r e s e n t  groundmass.  of the hornblende c r y s t a l l i z a t i o n  a minimum age  i s 104  ± 4  f o r the u l t r a b a s i c r o c k s and  the  m.y. en-  c l o s e d n o r i t e body as the date o b t a i n e d i s t h a t of the r e a c t i o n margin of  the two  rock  units.  Sample 120A complex.  i s t y p i c a l of a l a r g e volume o f h o s t r o c k w i t h i n the  I t i s a hornblendic pyroxenite with large p o i k i l i t i c  c r y s t a l s to 1 cm.  c o n t a i n i n g orthopyroxenes  groundmass i s a m i x t u r e Radiometric The 119  d a t i n g was  apparent  ± 4 m.y.  to 2.0 mm.  i n t e r l o c k i n g o r t h o - and  T h i s whole r o c k age may by  clinopyroxenes.  ± 4 to 119  Sample 79A-2, was  determined  as  be somewhat h i g h because o f a d i -  the v e r y low r a d i o g e n i c n a t u r e o f pyroxene.  the a v a i l a b l e K-Ar  b a s i c s between 104  The  done on the whole r o c k .  age of the h o r n b l e n d i c p y r o x e n i t e was  l u t i o n e f f e c t caused any event,  of t i g h t l y  from 0.2  hornblende  d a t i n g p l a c e s the minimum age ± 4  of the  In ultra-  m.y.  s e l e c t e d from a h o r n b l e n d i t e dyke, as i t r e p r e -  s e n t s the youngest rock u n i t seen i n underground mapping. mm.,  It i s a fine-  g r a i n e d , 0.1  to 1.0  monomineralic r o c k o f o r i e n t e d prisms o f  hornblende.  These f i n e - g r a i n e d hornblende or f e l d s p a t h i c hornblende  d^kes cut a l l o t h e r r o c k s and  c o n t a c t s are k n i f e - e d g e  these dykes or v e i n s a r e 2 to 4 i n c h e s wide and course.  The apparent  K-Ar  age  i s 95 ± 4  m.y.  sharp.  fresh  Most o f  f o l l o w a random, sinuous  68  G r a n i t o i d Rocks S e v e r a l samples from the s u r r o u n d i n g p l u t o n i c r o c k s were c o l l e c t e d and  three were s e l e c t e d f o r age  dating.  F i g . 38, a l o n g w i t h some e a r l i e r age  Sample #7 was  c o l l e c t e d 0.1  T h e i r l o c a t i o n s are shown i n  determinations.  m i l e s west from the c o n t a c t between  h i g h grade s c h i s t s and p l u t o n i c r o c k s on the road to the mine. sample (T. R i c h a r d s , p e r s . comm.) p r o b a b l y  This  r e p r e s e n t s the t o n a l i t e phase  of the Spuzzum P l u t o n and i s a f o l i a t e d medium-grained f r e s h f e l s i c I t c o n s i s t s of a n d e s i n e ,  q u a r t z , hornblende,  Both a b i o t i t e and hornblende K-Ar 85.1  ± 2.8  m.y.  Sample #4  date was  b i o t i t e and minor o b t a i n e d a t 79.4  chlorite.  ± 2.5  is a diorite  as major c o n s t i t u e n t s .  t h a t corresponds  to R i c h a r d s  (1971) phase  c l i n o p y r o x e n e , hornblende and p l a g i o c l a s e  T h i s sample was  f e e t of the u l t r a b a s i c complex.  The  c o l l e c t e d w i t h i n a few  l o c a t i o n i s about 400  hundred  f e e t along  lower haulage r o a d , a t the i n t e r s e c t i o n of the road and a s m a l l to Texas Creek.  ± 3.1  i s a phase I I d i o r i t e  o f H a i g j u n c t i o n on the main highway. ± 2.8  m.y.  tributary  m.y.  m i l e s to the south of the mine.  89.5  the  A hornblende-pyroxene c o n c e n t r a t e o f t h i s sample g i v e s  date of 89.6  Sample #8  and  respectively.  I I d i o r i t e h a v i n g hypersthene,  a K-Ar  rock.  The  ( R i c h a r d s , 1971)  collected several  sample l o c a t i o n i s 1.8  m i l e s west  the n o r t h s i d e o f the F r a s e r R i v e r i n a road c u t on T h i s hornblende c o n c e n t r a t e y i e l d e d a K-Ar  date o f  69  L O C A T I O N OF K - A r D A T I N G SPUZZUM  OF  FIGURE 38  PLUTONIC  ROCKS  79b 89h  BIOTITE HORNBLENDE  70  D i s c u s s i o n and I n t e r p r e t a t i o n Only one sample p r o v i d e d both a b i o t i t e and hornblende In t h i s case the hornblende s h o u l d be expected tends  g i v e s an o l d e r date by n e a r l y 6 m.y. I t  t h a t hornblende  a t a h i g h e r temperature  than does  T h i s r e t e n t i o n i s due to a more compact c r y s t a l s t r u c t u r e .  e v e r , the age s p r e a d appears it  would y i e l d an o l d e r age as the m i n e r a l  to " f r e e z e i n " r a d i o g e n i c argon  biotite.  K-Ar date.  How-  too g r e a t f o r t h i s to be the o n l y reason and  i s p o s s i b l e t h a t u n u s u a l l y slow c o o l i n g o f the i n i t i a l magma would  account  f o r the d i f f e r e n c e .  Because o f low potassium  c o n t e n t i n u l t r a m a f i c samples, see t a b l e 4,  they were r e a n a l y z e d and sample 157A-1 was dated d i f f e r e n c e s were Contamination  The  o f samples by the presence  o f pyroxene and c h l o r i t e  age o f c r y s t a l l i z a t i o n of the u l t r a m a f i t e s , o r a t l e a s t the  119 m.y.  old.  o r no e f f e c t on t h e r e -  (R.L. Armstrong, p e r s . comm.).  time when r o c k s ceased  95 m.y.  No s i g n i f i c a n t  found.  though u n d e s i r a b l e , i s b e l i e v e d t o have l i t t l e s u l t a n t age,  twice.  to l o s e r a d i o g e n i c argon, ranges between 104 and  L a t e h o r n b l e n d i t e dykes t h a t c u t the u l t r a m a f i t e a r e dated a t The e n c l o s e d n o r i t e s o r n o r i t i c phase must be a t l e a s t 104 m.y.  The Chinaman orebody i n p a r t i c u l a r would seem t o have a minimum  age o f 108 m.y., t h i s would p r o b a b l y r e p r e s e n t t h e age o f a l l o r e b o d i e s i n the complex. The  s u r r o u n d i n g p l u t o n i c r o c k s y i e l d K-Ar ages t h a t a r e concordant  ages w i t h Spuzzum i n t r u s i o n s  ( R i c h a r d s , 1971).  T o n a l i t i c r o c k s , as  suggested by R i c h a r d s , a r e the younger a t 79.4 to 85.1 m.y. r o c k s near  the u l t r a m a f i t e , s i m i l a r p e t r o l o g i c a l l y  Dioritic .  to those s e v e r a l m i l e s  to t h e south and c l a s s i f i e d as phase I I d i o r i t e s by R i c h a r d s  (1971)  71  yield  ages a t b o t h l o c a t i o n s o f 89.6  m.y.  These d a t e s agree f a i r l y  w i t h those o f the type l o c a l i t y of Spuzzum p l u t o n i s m (McTaggart Thompson, 1967) dated a t 76 m.y.  northwest The  o f S t o u t , B r i t i s h Columbia,  Comparison of K-Ar  that  dates from u l t r a m a f i t e s and s u r r o u n d i n g Spuzzum the problem  o f the r e l a t i v e ages o f  r o c k types because t h e r e are s e v e r a l v a r i e t i e s  n o t a l l o f these have been sampled o r dated. t h a t the u l t r a m a f i t e i s a t l e a s t diorites  ;  i s o l d e r than the Spuzzum I n t r u s i o n s .  d i o r i t e s does n o t c o m p l e t e l y s e t t l e these two  and  a t o n a l i t i c rock  d a t i n g o f the p l u t o n i c r o c k s a l o n e suggest  the G i a n t Mascot U l t r a m a f i t e  well  of d i o r i t e  and  I t i s apparent, however  as o l d and p o s s i b l y o l d e r than  t h a t do appear to b e l o n g to the Spuzzum I n t r u s i o n s .  certain  72  TABLE 4  Spec. No.  Min.  79A-2  Hbl.  120A  .  K/Ar samples and a n a l y t i c a l r e s u l t s f o r u l t r a b a s i c and p l u t o n i c rocks a t the G i a n t Mascot P r o p e r t y , near Hope, B.C.  Rock  %K  a  Ar  40*  /Ar  40  40* -5 A r ^ :10 Cm (stp)/g u  J  Whole Rock  Hblite Hbl.  pyrox.  3  Age myr  0.183  0.64  0.07043  95+4  0.130  0.43  0.06357  119+4  141A  Hbl.  Feld.  Hblite  0.258  0.64  0.1093  104-4  157A-1  Hbl.  Min.  Hblite  0.258  0.61  0.1154  108+4  Dio.  0.334  0.43  0.1214  89.6+3.1  Hbl.  4  - pxn.  7a  Bio.  Q.D.  5.860  0.836  1.881  79.4+2.5  7b  Hbl.  Q.D.  0.464  0.580  0.160  85.112.8  8  Hbl.  Dio.  .536  0.580  0.1945  89.512.8  Constants used i n age c a l c u l a t i o n s :  V K  4 0  /K  73  ORIGIN OF THE  ULTRAMAFITE AND  Ruckmick and Noble (1959), classified  Irvine,  (1967) d i s q u a l i f i e d i t on  t a i n s orthopyroxenes. t h a t i t was  intrusion". otherwise  T a y l o r (1967), and McTaggart  the G i a n t Mascot U l t r a m a f i t e as b e l o n g i n g  zoned type.  suggested  ITS ORES  to the  (1971), Alaskan  the grounds t h a t i t con-  F i n d l a y (1969) d i s q u a l i f i e d  i t on t h i s b a s i s and  "a v a r i a n t of the 'normal' C o r d i l T e r a n a l p i n e - t y p e  N a l d r e t t (1973) i s unable  detailed classification  to c l a s s i f y i t a t a l l i n h i s  system.  E a r l y i n v e s t i g a t o r s o f the G i a n t Mascot U l t r a m a f i t e proposed d i v e r s e o r i g i n s f o r the complex.  Cairnes  (1924) concluded  t h a t the  ultrabasic  rocks w i t h t h e i r r e l a t e d ore m i n e r a l s were magmatic i n o r i g i n and surrounding d i o r i t e s .  hydrothermal  to be  i n origin.  d i o r i t e and  Horwood (1936, 1937)  t h a t the  from the h o r n b l e n d i t e and  t h a t these were i n j e c t e d i n t o  p r e s e n t p o s i t i o n f o l l o w e d by r e l a t e d d i o r i t e  ore  believed hornblendite  the p r i n c i p a l rock type, t h a t the s u l f i d e ore and p y r o x e n i t e  segregated  the  C o c k f i e l d and Walker (1933) b e l i e v e d t h a t the  u l t r a b a s i c r o c k s were i n t r u d e d by s u r r o u n d i n g was  cut  had their  intrusions.  McTaggart (1971) f a v o r s a metasomatic o r i g i n f o r zoned u l t r a m a f i t e s and proposed t h a t d i o r i t e and mafite.  Muir,  gabbros might be younger than the  (1971) concluded  ultra-  t h a t the G i a n t Mascot U l t r a m a f i t e formed  from a i n i t i a l mass o f hornblende p y r o x e n i t e which i n t r u d e d a l o n g a diorite-metamorphic  rock c o n t a c t .  p l u g - l i k e o l i v i n e and  Subsequently  he suggested  s u l f i d e b o d i e s were i n t r u d e d a l o n g the  a number of diorite-  hornblende p y r o x e n i t e c o n t a c t . Aho  (1956) whose work a t G i a n t Mascot i s the most d e t a i l e d  o f f e r e d two h y p o t h e s i s  of o r i g i n , magmatic and metasomatic.  The  to  date,  magmatic  74  hypothesis followed mush  by  i n t o  the  f r a c t i o n a l  g r a v i t a t i v e  the  bodies. of  invoked  d i f f e r e n t i a t i o n  surrounding  hypothesis  zoned  m i n e r a l i z e d  pipes  mafic  and  suggested  and  to  mass  pyroxenite of  s i l i c a ,  The  and  i s  o r i g i n  r e l a t e d  of  r e l a t i o n  of  v a r i o u s  orebodies  A u n i t s  in  the  a d d i t i o n this  the  of  r e s u l t  i n  of  and  the  map  i n  by  p r e - e x i s t i n g rocks  by  a  shape, u n i t s .  formation, r e l a t e d  and  m i n e r a l  as  to  zoning  the  other  as  p r e v i o u s l y  the  o r i g i n  and  whole  u l t r a -  p e r i d o t i t e  to  r e d i s t r i b u -  s u l f i d e  m i n e r a l i z a -  The  (1971)  textures,  the  o r e -  i n t r u s i o n .  p r o c e s s . Muir  c r y s t a l  S i G ^  temperature  r e l a t e d  a  for  of  from  magma  massive  account  removal  On  seem  h i s  u l t r a b a s i c  (1956),  rocks  f o r  to  high  parent  i n j e c t i o n  or  complex  Aho  b a s i c  hypothesis  s c a l e  caused  u l t r a m a f i c  s i m i l a r  area. rock.  r e a c t i o n  high  sions  a  f i n a l  proposed  large  i s  d e s c r i b e d  mechanisms  g e o l o g i c a l  pyroxenite are  the  a  orebodies  and  by  m i n e r a l  hand,  the  assemblages  d i v e r s e  o u t l i n e d ,  incomplete  the  or  for  the  improbable  author.  metamorphic blende  i n  l i t h o l o g i c a l  and  t h i s  as  are  o r i g i n s  to  be  the  of  accounting  was  extended  that  e t c .  the  to  rocks  author  He  hornblendite  lime  b e l i e v e d  present and  s u l f i d e s .  by  and  thus  metasomatic  of  t i o n  d i o r i t e s  The  d e p o s i t i o n  t i o n  c r y s t a l l i z a t i o n  and  grade  and  The  (1956)  The  p o s s i b i l i t y i s  and  w i t h  centers  of  these by  i s  i s  s c h i s t s  to  and  fact  that  shows  d i o r i t e  crudely  the  p r i n c i p a l  w i t h  zoned  body  grading  I n c l u s i o n s  w i t h i n  h o r n f e l s e d  n o r i t e .  at  do  younger not  they  age  belong  the  are  f o r  to  u s u a l l y  w i t h  a  inwards  u l t r a m a f i c - d i o r i t e a  rock  i n c l u s i o n s  pyroxenite  p o s t u l a t e  i n c l u s i o n s  the  a  a  hornblende  r e l a t i o n s h i p s  (1971)  supported  rock  (1956),  p e r i d o t i t e .  metamorphic  that  Aho  u l t r a m a f i t e  margin  Muir  3,  country  c r o s s - c u t t i n g  Aho  trusions  The  F i g .  the  of hornto  u l t r a m a f i t e  F e l s i c  i n c l u -  contacts the  u l t r a m a f i t e .  Spuzzum  n o r i t e s  led  as  In-  75  opposed to Spuzzum d i o r i t e s , and  they have a much b e t t e r developed  the p l a g i o c l a s e c o m p o s i t i o n i s u s u a l l y much more c l a c i c ,  b y t o w n i t e as opposed to a n d e s i n e - l a b r a d o r i t e , Spuzzum,  A l s o Aho  foliation  basic  c h a r a c t e r i s t i c of  the  (1956) s t a t e s t h a t u l t r a m a f i c - d i o r i t e c o n t a c t s  show  c o n f l i c t i n g age r e l a t i o n s h i p s . K-Ar  age  d e t e r m i n a t i o n s support the i d e a t h a t the u l t r a m a f i t e i s  o l d e r than the Spuzzum D i o r i t e . rite few  c r y s t a l l i z a t i o n from 80 hundred f e e t from the  T h i s work and  to 89 m.y.  o t h e r s y i e l d ages of  w i t h the o l d e s t date o b t a i n e d  south e a s t c o r n e r  o f the u l t r a m a f i t e .  t o n a l i t e b o r d e r phase of the Spuzzum appears younger and b i o t i t e p a i r dated a t 85 and  79 m.y.  dioa  The  a hornblende-  r e s p e c t i v e l y suggest a  protracted  c o o l i n g f o r the Spuzzum p l u t o n i s m . K-Ar  d a t i n g of h o r n b l e n d i c  o l d e r ages of c r y s t a l l i z a t i o n . blendic-pyroxenite and  suggesting  m.y.  I t may  be  i n a p o s i t i o n of b e i n g  mass and  ultra-  clock.  and age  dykes, o b s e r v e d to still  older  cut  than  difference i s false  and  f o r "freezing i n " radiogenic this s t i l l places  the  ultra-  a t l e a s t as o l d as Spuzzum p l u t o n i s m .  i t can be argued t h a t the u l t r a m a f i c i s the o l d e r  Spuzzum p l u t o n i s m  radiogenic  of 95 m.y.,  argued t h a t the age  components e a r l i e r than does d i o r i t e b u t  realistically,  m.y.  a minimum f o r both n o r i t e  Young h o r n b l e n d i t e  to the c a p a c i t y of u l t r a m a f i c r o c k s  mafite  o f c r y s t a l l i z a t i o n o f 119  between an i n t e r n a l n o r i t e and  u l t r a m a f i c r o c k u n i t s , y i e l d an age  Spuzzum r o c k s .  yield  Hornblende from the Chinaman orebody y i e l d s a minimum  o f c r y s t a l l i z a t i o n o f 108  due  m.y.  the u l t r a m a f i t e  From the c e n t e r o f the complex a h o r n -  hornblendite  m a f i c y i e l d s a date of 104  all  from w i t h i n  y i e l d s a minimum age  a coarse-grained  ultramafite.  rocks  caused an uneven younging e f f e c t ,  More  rock  r e s e t t i n g the  76  From t h e evidence  obtained  i t i s suggested t h a t the u l t r a m a f i t e  c r y s t a l l i z a t i o n i s a minimum o f 15 m.y. o l d e r than the Spuzzum I n t r u s i o n s and  the a c t u a l age o f t h e u l t r a m a f i t e may be c o n s i d e r a b l y o l d e r .  This  sequence o f events may w e l l e x p l a i n some o f t h e secondary f e a t u r e s seen by Aho i n t h e study o f the o r e b o d i e s , textures along  the b r e c c i a t i o n and p r o t o c l a s t i c  t h e f o o t w a l l o f the 1900 and Chinaman o r e zones and a  crude metasomatic i m p r i n t  ( h o r n b l e n d i t e margin) on the u l t r a m a f i t e  itself.  D i s t r i b u t i o n c o e f f i c i e n t s f o r pyroxenes i n d i c a t e o r i g i n by magmatic c r y s t a l l i z a t i o n o f G i a n t Mascot u l t r a m a f i c r o c k s . suggests e q u i l i b r a t i o n w i t h o f 990°C.  a minimum mean temperature o f c r y s t a l l i z a t i o n  These c o n s i d e r a t i o n s s u g g e s t t h a t t h e G i a n t Mascot U l t r a m a f i t e  o r i g i n a t e d from a magmatic source i n composition, tion.  and t h a t Spuzzum P l u t o n i s m ,  F u r t h e r , a t temperatures o f f o r m a t i o n  Chemical a n a l y s e s  i n t h e range o f 1000°C a  o f s i l i c a t e s and a s u l f i d e m i n e r a l w i t h i n the v a r i a t i o n s from p e r i d o t i t e s t o  P e n t l a n d i t e s a r e d i f f e r e n t c o m p o s i t i o n a l l y i n each o f the  rock u n i t s and a r e d i f f e r e n t a g a i n i n o r e zones.  I t seems c e r t a i n  t h a t no theory o f s i n g l e magmatic i n j e c t i o n o r accumulation these  observations  origin.  can e x p l a i n  but that multiple i n j e c t i o n s of d i f f e r e n t  p o s s i b l y f o l l o w e d by s e p a r a t e Textures  equilibra-  the u l t r a m a f i c magma.  u l t r a m a f i t e show marked c o m p o s i t i o n a l pyroxenites.  intermediate  d i d n o t e f f e c t K^'s o r temperatures o f pyroxene  s u l f i d e l i q u i d could coexist with  two  Pyroxene geothermometry  compositions,  o r e i n j e c t i o n s , may.  must be taken i n t o account i n working o u t a h y p o t h e s i s o f  T e x t u r a l l y the p e r i d o t i t e s show o l i v i n e - p y r o x e n e  hornblende t e x t u r a l types  or o l i v i n e -  i n d i s t i n g u i s h a b l e from heteradcumulates found  i n l a y e r e d r o c k s from Rhum, Skaergaard e t c . l a t e - l i k e i n texture although  Pyroxenites  heteradcumulate-like  appear adcumu-  t e x t u r e s a r e seen.  77  In  p a r t i c u l a r , hornblende  i n p y r o x e n i t e s forms c l e a r  heteradcumulate  textures. M i c r o s c o p i c a l l y o l i v i n e s and pyroxenes appear somewhat deformed near  c o n t a c t s s u g g e s t i n g movement a f t e r some c r y s t a l l i z a t i o n .  a l s o t r u e o f some s u l f i d e s , p a r t i c u l a r l y orebody.  c h a l c o p y r i t e i n the Chinaman  Between the c o n t a c t of p e r i d o t i t e and w e b s t e r i t e a t the  ore zone t h i s d e f o r m a t i o n  Climax  i s noted a l o n g w i t h v a r i a b l e amounts o f o l i v i n e  which appear to make a h y b r i d - t y p e r o c k between the two units.  This i s  I t has been suggested by Muir  end member r o c k  (1971) t h a t a s i m i l a r  i n the 4600 orebody i s the r e s u l t o f m i x i n g of two  occurrence  c r y s t a l mushes to  produce what he c a l l e d a " h y b r i d zone". Structurally,  the ore zones appear r e l a t e d  to l i t h o l o g i c a l  contacts  m a i n l y between p e r i d o t i t e and p y r o x e n i t e , forming s t e e p l y p l u n g i n g p i p e -  line  o r e b o d i e s w i t h the s u l f i d e s c o n c e n t r a t e d mainly on  the p i p e .  The  tween the two  the f o o t w a l l of  ore zones are e i t h e r massive s u l f i d e c o n c e n t r a t i o n s bep r i n c i p a l u l t r a m a f i c phases o r i n a p i p e - l i k e body, zoned  from hornblende  r i c h r o c k s to p e r i d o t i t e i n the cores w i t h o r e m i n e r a l s  c o n c e n t r a t e d a l o n g the f o o t w a l l .  The p r o x i m i t y o f n o r i t i c phases w i t h i n  the u l t r a m a f i t e appear to have some i n f l u e n c e , p o s s i b l y s t r u c t u r a l ,  on  the l o c a l i z a t i o n of o r e . The m a j o r i t y o f the o r e b o d i e s l i e a l o n g a l i n e near  the south-west  p a r t o f the complex w i t h some e x c e p t i o n s , the Chinaman b e i n g more c e n t r a l to  the u l t r a m a f i t e .  approximately by  The o r e zones appear to terminate downwards a t  the 2600 f o o t e l e v a t i o n .  the bottoming  T h i s t e r m i n a t i o n may  o f the u l t r a m a f i c r o c k s a t 250  to 400  f e e t below  l e v e l as i n d i c a t e d by downhole d r i l l i n g which encounters d i o r i t i c rocks.  be i n f l u e n c e d this  metamorphic  Some o r e b o d i e s r e a c h the s u r f a c e ; o t h e r s weaken o r  and  78  d i m i n i s h , or a r e f a u l t e d o f f . The  author  c o n s i d e r s the f o l l o w i n g hypotheses f o r the o r i g i n  the G i a n t Mascot U l t r a m a f i t e and (1)  i t s ores:  M u l t i p l e i n j e c t i o n s of u l t r a b a s i c magmas, o f f e r i n g compositions, Alaskan  (2)  The  type  of  dif-  to form a zoned complex o f  the  (Ruckmick and N o b l e , 1959).  emplacement of an u l t r a m a f i c body i n a s o l i d  or  magmatic s t a t e w i t h subsequent metasomatic m o d i f i c a t i o n by Spuzzum (3)  Plutonism.  M u l t i p l e i n j e c t i o n of c r y s t a l mush and melts  d e r i v e d from a d i f f e r e n t i a t i n g  sulfide  intrusion  l o c a t e d a t some g r e a t e r depth. (4)  D i a p i r i c re-emplacement o f r u d e l y s t r a t i f o r m quences of cumulates and "mushy" form and  provided  in a  d e r i v e d from a d i f f e r e n t i n g  volcanic intrusion The  sulfides s t i l l  se-  sub-  ( I r v i n e , 1974).  f i r s t h y p o t h e s i s would a c c o u n t f o r the o r i g i n o f the u l t r a m a f i t e t h a t more than one  time w i t h i n the s t o c k and r u p t e d and  rearranged  A l s o the s i z e and  age  c e n t e r of i n j e c t i o n was  that subsequently  operative at  one  the Spuzzum i n t r u s i o n s d i s -  the z o n i n g , and metasomatized the u l t r a m a f i t e . r e l a t i o n s h i p s of the u l t r a m a f i t e to the  g r a n i t i c t e r r a n e i s remarkably s i m i l a r to those o f the A l a s k a n  surrounding type.  I t must be p o i n t e d out however, t h a t the G i a n t Mascot U l t r a m a f i t e d i f f e r s i n s e v e r a l important  r e s p e c t s from the A l a s k a n  type.  These  d i f f e r e n c e s a r e : (1) the l a c k of graded l a y e r i n g i n r h y t h m i c a l beds as noted  i i i some A l a s k a n  Complexes; (2) the p r e s e n c e of s e v e r a l c r u d e l y  zoned p e r i d o t i t e c e n t e r s ; (3) l a t e h o r n b l e n d i t e dykes c u t t i n g a l l rock  i  79  u n i t s a t G i a n t Mascot; (4) the abundance o f orthopyroxene; presence olivine  the  o f p l a g i o c l a s e ; (6) t h e r e s t r i c t e d c o m p o s i t i o n a l range o f (FOg^-Fo^g); (7) the r e s t r i c t e d  c o m p o s i t i o n a l range o f c l i n o -  pyroxene ( D i g g H e d ^ - D i ^ Hed^^) compared to A l a s k a n (Dig^Hed^-Di^QHed^Q); and (8) the presence f i d e s a t G i a n t Mascot. result of differing size  (5)  clinopyroxene  o f abundant N i and Cu s u l -  Some o f these c h e m i c a l d i f f e r e n c e s may be the  compositions  o f i n i t i a l magmas o r the much s m a l l e r  (and t h e r e f o r e l e s s d i f f e r e n t i a t e d ? ) o f the G i a n t Mascot body.  Naldrett  (1973) suggests  t h e chemical  d i f f e r e n c e s may n o t be a t t r i b u t e d  to d i f f e r e n t mechanisms o f f o r m a t i o n b u t to t h e depths a t w h i c h u l t r a m a f i c magmas have o r i g i n a t e d .  Furthermore, t h e r e a r e s e r i o u s o b j e c t i o n s  to t h e Ruckmick-Noble h y p o t h e s i s .  The younger, more u l t r a b a s i c magmas  i n A l a s k a a r e n o t seen t o c u t t h e o l d e r l e s s u l t r a b a s i c r o c k s .  Further,  t h e r e remains the more g e n e r a l problem o f p r o d u c i n g a d u n i t e o r p e r i d o t i t e magma. The  second mechanism, i n v o l v i n g metasomatism o f a p r e - e x i s t i n g  u l t r a m a f i t e has some support  i n t h a t a l p i n e u l t r a m a f i t e s to t h e n o r t h -  west o f G i a n t Mascot i n t h e v i c i n i t y o f The O l d S e t t l e r mountain show i n c r e a s i n g metamorphic grade where i n c o n t a c t w i t h Spuzzum d i o r i t e . P y r o x e n i t e s a r e t h e r e developed resemble those a t G i a n t Mascot.  w i t h minor Ni-Cu showings and these Trommsdorff and Evans, (1972),  have  d e s c r i b e d , i n the Swiss A l p s , s e r p e n t i n i t e s metamorphosed to pyroxene, amphibole and o l i v i n e .  Thus, i f an a l p i n e u l t r a m a f i t e were e n g u l f e d by  the Spuzzum magmas, c o n v e r s i o n and metasomatism might o c c u r and g i v e rise  to a zoned body w i t h  t h i s m i n e r a l assemblage.  Nickel mineralization  c o u l d p o s s i b l y r e s u l t by r e d i s t r i b u t i o n and c o n c e n t r a t i o n d u r i n g metamorphism o f n i c k e l o r i g i n a l l y h e l d i n s i l i c a t e s such as o l i v i n e and p e r -  80  haps r e l e a s e d d u r i n g  serpentinization.  T h i s mechanism i s n o t a c c e p t a b l e f o r G i a n t Mascot because s u l f i d e t e x t u r e s suggest a magmatic o r i g i n w i t h p r e c i p i t a t i o n from a l i q u i d which would be a t l e a s t a t 1000°C.  Temperatures o f f o r m a t i o n o r e q u i -  l i b r a t i o n o f the u l t r a m a f i t e (2-pyroxene geothermometer) was a p p a r e n t l y near 1000°C., much h i g h e r than would be r e a s o n a b l y expected i n c l u s i o n heated by Spuzzum d i o r i t e magma.  i n a sizeable  Furthermore, t e x t u r e s o f the  p r i n c i p a l u l t r a b a s i c m i n e r a l s a r e more magmatic-looking than metamorphic. Although  the g e n e r a l h y p o t h e s i s  seems untenable,  i t seems c e r t a i n  t h a t t h e c o a r s e - g r a i n e d h o r n b l e n d i t e margin i s metasomatic, b u t the metamorphic e f f e c t extends n o t much f u r t h e r than 100 yards..... I n a d d i t i o n , d u r i n g t h e emplacement o f the Spuzzum, there were  developed  l a t e h o r n b l e n d i t e dykes which c u t a l l rock u n i t s w i t h i n t h e complex, and  t h e r e was a l s o some r e d i s t r i b u t i o n o f o r e m i n e r a l s  ly,  l e d Aho to p o s t u l a t e a hydrothermal The  (which,  incidental-  o r i g i n f o r some o r e b o d i e s ) .  t h i r d h y p o t h e s i s , i n j e c t i o n o f c r y s t a l mushes from a d i f f e r e n t i a t -  i n g body (Bowen and T u t t l e , 1949), appears to o f f e r a p l a u s i b l e t i o n f o r the g e n e s i s o f t h e G i a n t Mascot Complex. mushes r a n g i n g i n c o m p o s i t i o n  explana-  Several i n j e c t i o n s o f  from h o r n b l e n d i c p y r o x e n i t e , t o p y r o x e n i t e ,  to p e r i d o t i t e i n t h a t o r d e r w i t h the l a t e r , more magnesian, magmas emp l a c e d a l o n g s e v e r a l c e n t e r s would account  f o r the crude  z o n a t i o n o f the  u l t r a m a f i t e on t h e whole and the z o n a t i o n around some o r e zones. ore-forming  The  s u l f i d e m e l t s would be, a p p a r e n t l y , i n j e c t e d l a s t o r a l o n g  w i t h the p e r i d o t i t e mush which, on c o o l i n g , formed the h o s t r o c k f o r t h e n e t - t e x t u r e d and massive  sulfides.  T h i s h y p o t h e s i s a l t h o u g h p l a u s i b l e i s complex and i n c o m p l e t e . s i m p l e r and more complete one, t h a t o f I r v i n e (1974),  A  r e t a i n s the i d e a  81  of c r y s t a l mushes d e r i v e d from a d i f f e r e n t i a t i n g body b u t o f f e r s an a l t e r n a t i v e method o f emplacement. A f o u r t h h y p o t h e s i s , making use o f I r v i n e ' s mechanism (1974), i n v o l v e s d i a p i r i c re-emplacement cumulates and s u l f i d e s ,  o f r u d e l y s t r a t i f o r m sequences o f "mushy"  t h a t have p r e c i p i t a t e d i n a d i f f e r e n t i a t i n g sub-  v o l c a n i c magma chamber i n the o r d e r : to hornblende p y r o x e n i t e .  s u l f i d i c p e r i d o t i t e , pyroxenite  These magmas may r e p r e s e n t the e a r l i e s t  Spuzzum magmatism. D i a p i r i s m c o u l d r e s u l t from a d d i t i o n s o f magmas (Spuzzum?) from depth through f e e d e r s i n t o  the magma chamber, from upward f o r c e a p p l i e d  by the r i s i n g Spuzzum magmas o r from t e c t o n i c compression.  Although  e r o s i o n has removed t h e p o s t u l a t e d o v e r l y i n g v o l c a n o e s , t o t h e e a s t , t h e Spences B r i d g e (Lower C r e t a c e o u s ) and the K i n g s v a l e ( l a t e Lower C r e t a c e o u s ) Groups r a n g i n g i n c o m p o s i t i o n from a n d e s i t e s to b a s a l t s show t h a t v o l c a n i s m was widespread a t t h i s T h i s p r o c e s s o f re-emplacement  ( R i c e , 1947)  time.  by d i a p i r i s m might r e a d i l y  the crude z o n a t i o n w i t h i n the u l t r a m a f i t e  explain  ( e x c l u d i n g the m a r g i n a l h o r n -  b l e n d i t e ) and accounts v e r y w e l l f o r s e v e r a l f e a t u r e s seen on t h e 3050 c r o s s - c u t such a s : (1)  The sharp change i n m i n e r a l c o m p o s i t i o n both s i l i c a t e s and s u l f i d e from one r o c k type to another.  (2)  The h y b r i d p y r o x e n i t e on t h e f o o t w a l l o f the Climax orebody, p o s s i b l y  the consequence o f  m i x i n g o f two c r y s t a l mushes. (3)  The s t r a i n e d s i l i c a t e s i n the Climax zone between p y r o x e n i t e and p e r i d o t i t e .  82  (4)  The  p r o t o c l a s t i c  Chinaman (5)  The  (6)  zone  on  the  of  the  orebody.  c l o s e  s p a t i a l  r e l a t i o n s h i p  p e r i d o t i t e  and  p a r t i c u l a r l y  d o t i t e s  the  ore  The  f o o t w a l l  in  of  s u l f i d e s  net-textured  to  p e r i -  zones.  heteradcumulate-like  nature  of  the  s i l i -  cates. With  the  metasomatic  u l t r a m a f i t e , complex  t h i s  Spuzzum,  f o l i a t i o n  i n  the  t h e l e s s ,  i r r e g u l a r l y  contains  augite  F e - r i c h  than  contain  quartz  Giant  noted  about  those  Mascot.  and  6  An  a l t e r n a t i v e  i s  that  Chemical  Spuzzum d i o r i t e s  i n  cut  of  these  are  comparisons strongly  thus  In  strongly between the  the  for  These  are  the  but  these  a r e ,  P y r o x e n i t e  small  more  bodies  are  p r e - e x i s t i n g  s m a l l  w i t h  never-  10-20%  bodies  metamorphosed  f i r s t  and  u l t r a m a f i t e s  these  along  the  a l i g n e d  d i r e c t i o n s .  from  these  i n  p e r i d o t i t e  a d d i t i o n  d i o r i t e s  support  to  hypersthene  that  w e l l  bodies  f o l i a t i o n  d i f f e r  suggests the  long,  and  on  Mascot.  f o l i a t i o n  F e - r i c h  reasonably  u l t r a b a s i c  across  along  and  Giant  length.  Mascot.  (1971)  replacement  and  or  andesine,  metasomatic  5  inches  Giant  by  x e n o l i t h s .  feet  10% m o r e  Richards  at  up  to  S p u z z u m magmas  account  small  elongated  at  to  s e v e r a l  d i o r i t e  about  subsequent  observed  hornblendite  l e n s e s ,  of  appears  features  (1971)  from  pyroxenite the  mechanism  g e o l o g i c a l  Richards  e f f e c t s  a l l  at formed f r a c t u r e s .  ultramafic  pyroxenite  hypothesis.  lenses  CONCLUSIONS  A b r i e f summary o f some o f the more important f i n d i n g s made d u r i n g the course o f t h i s study are g i v e n below:  (1)  K-Ar is  d a t i n g i n d i c a t e s that the u l t r a m a f i t e  (119  m.y.)  as o l d as or p r o b a b l y o l d e r than Spuzzum P l u t o n i s m  (89 m.y.). (2)  Formation at  (3)  a mean minimum temperature  coefficient  0.738, i n d i c a t i v e o f magmatic f o r m a t i o n .  Pyroxene, and p a r t i c u l a r l y orthopyroxene, different  The  i s markedly  i n a d j a c e n t p y r o x e n i t e s and p e r i d o t i t e s , w i t h  M g - r i c h pyroxenes (5)  o f 990°C.  Pyroxene p a i r s have a mean d i s t r i b u t i o n of  (4)  or e q u i l i b r a t i o n o f pyroxene p a i r s o c c u r r e d  in peridotite.  c o m p o s i t i o n of o l i v i n e appears  to v a r y  b u t the most Mg-rich i s found i n the Climax  little hanging  wall. (6)  P e n t l a n d i t e i s Fe- and N i - r i c h w i t h l i t t l e  Co i n o r e -  b o d i e s , i s C o - r i c h and s l i g h t l y Fe- and N i - p o o r i n p y r o x e n i t e s and i s F e - r i c h and N i - p o o r i n p e r i d o t i t e . (7)  M i n e r a l t e x t u r e s i n the more magnesian r o c k u n i t s a r e s i m i l a r to cumulate t e x t u r e s observed  i n layered  complexes. (8)  C o n t a c t s between u l t r a m a f i c rock u n i t s are u s u a l l y sharp on a megascopic s c a l e and g r a d a t i o n a l m i c r o s c o p i c a l l y .  (9)  The Climax and Chinaman o r e b o d i e s plunging  p i p e - l i k e bodies with  sections concentrated  are steeply  the h i g h e r  grade  i n the trough o r f o o t w a l l  zone. (10)  The Climax orebody l i e s a t a c o n t a c t between pyroxenite  and p e r i d o t i t e whereas t h e Chinaman  appears t o be c r u d e l y zoned around a p e r i d o t i t e core.  Both a r e s p a t i a l l y r e l a t e d to a n o r i t e  body. In c o n c l u s i o n ,  the w r i t e r m a i n t a i n s t h a t the g e n e s i s  of the  G i a n t Mascot U l t r a m a f i t e i n v o l v e s a d i a p i r i c re-emplacement o f r u d e l y s t r a t i f o r m c r y s t a l mushes and s u l f i d e s from a d i f f e r e n t i a t i n g subv o l c a n i c body, p o s s i b l y an e a r l y phase o f Spuzzum magma a c t i v i t y . Subsequently t h i s m a t e r i a l was e n g u l f e d b y the r i s i n g Spuzzum d i o r i t i c magmas and a metasomatic h o r n b l e n d i t e imposed on the u l t r a m a f i t e .  m a r g i n a l zone was  REFERENCES CITED  Aho, A.E.  (1956) Geology and g e n e s i s o f u l t r a b a s i c n i c k e l - copper -  p y r r h o t i t e d e p o s i t s a t the P a c i f i c N i c k e l P r o p e r t y , southwestern B r i t i s h Columbia.  Econ. G e o l . v o l . 51, pp. 444-481.  Armstrong, R.L. ( p e r s . comm.) 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(1937) Magmatic s e g r e g a t i o n and m i n e r a l i z a t i o n o f the N i c k e l Mine, Choate, B.C. pp.  T r a n s . R o y a l Soc. Canada,  sec 4,  5-14.  H u t c h i s o n , W.W.  (1970) G e o l o g i c a l Survey paper S e r i e s , Age D e t e r m i n a t i o n s  and G e o l o g i c a l S t u d i e s . I r v i n e , T.N. Alaska.  G e o l . Surv. Can., Paper  71-2.  (1967) The Duke I s l a n d U l t r a m a t i c Complex,  southeastern  U l t r a m a f i c and r e l a t e d r o c k s (ed. P . J . W y l l i e ) ,  84-96, New  York John W i l e y and  Southeastern Alaska.  pp.  Sons.  (1974) P e t r o l o g y o f the Duke I s l a n d U l t r a m a f i c  K r e t z , R.  B.C.  G e o l . Soc. Amer., Mem.  138.  (1961) Some a p p l i c a t i o n s o f thermodynamics  minerals of v a r i a b l e composition.  Complex  to c o e x i s t i n g  J . G e o l . 69, pp.  361-387.  (1963) D i s t r i b u t i o n o f magnesium and i r o n between o r t h o pyroxene and c a l c i c pyroxene i n n a t u r a l m i n e r a l assemblages.  Ibid.  71, pp. 772-785. K u l l e r u d , G., Yund, R.A.,  and Moh,  G.H.  (1969) Phase r e l a t i o n s  i n the  Cu-Fe-S, Cu-Ni-S, and Fe-Ni-S systems, _in Magmatic Ore D e p o s i t s , Monograph 4, Econ. G e o l . , pp. 323-343. M a t t i n s o n , J.M.  (1970) Uranium-Lead  Cascades, Washington  Geochronology o f the N o r t h e r n  (abs.) Geol. Soc. Amer., C o r d i l l e r a n  66th A n n u a l M e e t i n g , pp.  116.  Section,  McTaggart, K.C.,  and Thompson, R.M.  (1967) Geology o f p a r t o f the  n o r t h e r n Cascades i n s o u t h e r n B r i t i s h Columbia. S c i . , v o l . 4, pp. McTaggart, K.C. Mountains. '  Can. J . E a r t h  1191-1228.  (1970) T e c t o n i c H i s t o r y o f the N o r t h e r n Cascade G e o l . A s s o c . o f Canada, s p e c i a l paper No.  6, pp.  (1971) On  B u l l . 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R i c e , H.M.A. (1947) Geology and M i n e r a l D e p o s i t s o f t h e P r i n c e t o n Map-Area, B r i t i s h Columbia. R i c h a r d s , T.A. parallel.  G e o l . Surv. Can., Mem.  (1971) P l u t o n i c r o c k s between Hope, B.C. U n p u b l i s h e d Ph.D.  Roddick, J.A. and H u t c h i s o n , W.W. Map-area, B r i t i s h Columbia. Ruckmick, J.C., and Noble, J.A. a t Union Bay, pp. 981-1018.  243. and the 49th  thesis, University of B r i t i s h  Columbia.  (1969) N o r t h w e s t e r n p a r t o f Hope G e o l . Surv. Can., Paper 69-1A, pp. (1959) O r i g i n o f the u l t r a m a f i c  southeastern Alaska.  Bull.  29-38  complex  G e o l . Soc. Amer., 70,  S t r e c k e i s e n , A. Rocks,  (1967) C l a s s i f i c a t i o n and Nomenclature  ( F i n a l Report of an I n q u i r y ) .  Abhandlungen  107, pp.  144-240., in  Sutherland-Brown, A., e t . a l .  Igneous  Neues Jahrbuch f u r M i n e r a l o g i  Geotimes, O c t o b e r  1973.  (1971) M e t a l l o g e n y the Canadian  Can. I n s t . M i n i n g Met., v o l . 74, pp. T a y l o r , H.P.,  of  Cordillera.  121-145.  J r . (1967) The zoned u l t r a m a f i c complexes  of southeastern  A l a s k a , i n U l t r a m a f i c and r e l a t e d r o c k s (ed. P . J . W y l l i e ) , York, John W i l e y and Trommsdorff,  New  Sons.  V., and Evans, B.W.  (1972) P r o g r e s s i v e metamorphism o f  A n t i g o r i t e s c h i s t i n the B e r g e l l T o n a l i t e a u r e o l e ( I t a l y ) .  Am.  J o u r . S c i . , v o l . 272, pp. 423-437. Wood, B . J . , and Banno, S.  (1973) Garnet-Orthopyroxene and  C l i n o p y r o x e n e r e l a t i o n s h i p s i n s i m p l e and complex M i n e r a l . P e t r o l . , v o l . 42, pp.  109-124.  Orthopyroxene  systems.  Contr.  Appendix 1 Sample L o c a t i o n Map  Appendix  2  Geology o f Climax  2  O O 05 CD  Approx. Outline  z o o o  7000E. S  Climax  Ore  /  / / // 9a  !  • l  f  j Pelt.  Pxnite  ] Norite •  •v • ~xr~~  Joint . Fault  •  GEOLOGY OF 3050  CLIMAX  X-CUT  92  Appendix 3 Cu, N i , and Cu/(Cu+Ni) Assay Contour P l o t s , Chinaman and Climax O r e b o d i e s  76  «1  i o  CM 3206. CU/NI+CU O«.0  IDSO.O  -r GUO.O  6830.0  6820.0'  BP«.0  GS60.0  6DC3.0 t>?00.0 F-OXIS  -1 63JO.0  -1 M«).D  1 69C3.D  1 6°f0.0  —I IOOO.O  1 IOIO.O  •/OO.O  oo  100  o LO CD C\J CO  , •D9S8  —  i D'D>53  1  1  r  i  D'K33  0DC98  C KS3  DKS3  i D'D?S3  SIXb'-N  ^ O'KiS  i DD0S3  101  8  7060.0 _1  &  eoi  105  8  OO ' OOt  SIXO-N  108  Appendix 4 Microprobe Analyses of S i l i c a t e s  N.B.  F o r sample number c o r r e l a t i o n see p. 62.  MICROPROBE ANALYSIS OF ORTHOPYROXENES 1 Si Al Ti Cr Fe Mn Mg. Ca Na K  55.37 3.13 .23 .42 12.09 n.d. 29.72 .68 '.03 " n.d.  2  3  4  5  6  7  8  54.84 2.62 .18 .12 12.74 n.d. 30.03 .69  54.18 2.38 .07 .23 13.41 n.d. 29.78 .35  54.90 2.28 .24 .19 12.68 n.d. 27.60 1 .09  n.d.  n.d.  n.d.  53.40 2.64 .32 .26 13.94 n.d. 26.47 1.24 .07 n.d.  54.695 2.128 .239 .190 14.062 n .d. 28.631 1.154 .012 n.d.  54.567 2.110 .420 .252 12.236 n.d. 29.896 .796 .052 n.d.  54.96 1 .52 .20 .12 11 .93 n.d. 28.49 1.20 .02 n.d.  101.22  100.40  98.95  98.34  101 .111  100.329  98.44  -  101.67  -  -  Formulae based on 6 oxyqens  Oxides Si Al Al Ti Cr Fe Mn Mg Ca Na K  1.928\ .072;  ? L  ,00  .00  .056\ .006 .012 .352 \ 1.99 1.543 .025 .002 /  Mg = 80 45% Fe = 18 25% Ca = 1 30%  .01 1 .572 .026  1.924 2.00 .076 .024\ .002 .006 .398 V ,020 1.577 .013 2  -J  Mg = 79.65% Fe = 18.95% Ca = 1.40%  Mg = 79.30% Fe = 20.05% Ca = 0.65%  1.9681 .032j 2.00  1.944\ 2.00 .056^ .0571 .064> .009 .006 .007 .0051 .424 .380 1 .972 1.99 1.475 1.437 .048 .042 .005 j  Mg = 77 .75% Fe = 20 .00% Ca = 2 .25%  Mg = 75.25% Fe = 22.20% Ca = 2.55%  1 .937 2.00 .063 .026\ .006 .005 • 1 >2 .01 1 .511 .044 .001 4  6  Mg = 76 .65% Fe = 21 .10% Ca = 2 .25%  5  1 .932 2.00 .068 .020"! .011 .007 .362  1.977\ .023;  1 .577 .030 .003  1 .527 .046 .001  .04n  .005 .003 \ .359 V  2.01  Mg = 80 .05% Fe = 18 .40% Ca = 1 .55%  1 .98  Mg = 78.85% Fe = 18.65% Ca = 2.50%  cont .d..../2 1  2.00  9  Si AT Ti Cr Fe M.n Mg Ca Na K  56.075 2.074 .165 .344 11.305 .160 30.863 1 .110 .011  10  11  56.325 1.673 .134 .370 12.028 .140 31.131 1.043  56.869 1.595 .205 .214 9.612 n.d. 32.088 1.079 .042 n.d.  -  -  101.844  102.107  57.247 2.316 .384 .370 8.809. n.d. . 32.526 .648 .081 n. d. 102.381  101.704  13  14  15  53.824 2.557 .197 .323 8.500 n.d. 31 .164 .759  55.544 2.279 .248 .482 8.190 n.d. 32.482 1 .212  55.62 1.78 .04 .12 8.67 n.d. 32.44 .92  n.d.  n.d.  53.232 2.166 .320 .173 13.920 n.d. 28.772 .526 .057 n.d.  97.325  100.437  99.166  99.59  -  -  16  -  n.d.  Formulae based on 6 oxygens  Oxides Si Al Al Ti Cr Fe Mn Mg Ca Na K  12  1.960] .040; .027\ .028^ .004, .003 .009 .010 \ .327 \ 2.007 •350 V .005 .004 ' 1.593 \ 1 562 .041 j 039 .0017 \ 2 ^00 .Q58J  l l 9 4 2  u u  Mg = 81.20% Fe = 16.70% Ca = 2.10%  2  0 uu  99  Mg = 80.00% Fe = 18.00% Ca = 2.00%  .00  .002  Mg = 83.75% Fe •= 1 4 / Ca = 2.  1.949] . 0 5 l j 2.00 .042^1 .010 .010 .251 n.d. 1.99 1.650 .024 .005 n.d./ Mg = 85.65% Fe = 13.10% Ca = 1.25%  1 .931 .069 00 .039\ .005 .009 .255\ n.d. 2.003 1.666 .029  .00  .00  .00  .00  .02  .06 1 .695 .034  1.683 .045  n.d./ Mg = 85.45% Fe = 13.05% Ca = 1  Mg = 85.60% Fe = 12.10% Ca = 2.30%  Mg = 77.85% Fe = 21.15%: Ca = 1.00%  Mg  =  85.40S  Fe .= 12.70% Ca = 1.70%  17 Si  18  57.507 1.985 .093 .185 8.895 n.d. 32.504 1 .122  Al  Ti Cr Fe Mn Mg Ca Na K  n.d.  55.094 1.538 .144 .052 10.538 n.d. 31.253 .937 .005 n.d.  102.291  99.671  -  19  . 20  53.074.2.953 .170 .065 15.021 n.d. 28.176 1.286  55.016% 2.962 .154 .808 9.557 n.d. 31 .122 2.275 .267 n.d.  -  n.d.  22  23  52.171 2.079 .198  52.303 4.912 .053  n.d.  51.954 2.935 .155 .038 15.634 n.d. 28.441 .636 .033 n.d.  11.495 n.d. 30.161 .661 .037 n.d.  56.229 2.425 .060 .217 9.710 n.d. 32.246 .619 .058 n.d.  101.621  99.826  99.622  101.564  -  24.146 n.d. 22.211 .816  -  102.161  100.749  21  -  24  Formulae based on 6 oxygens  Oxides Si  1.961 .039  Al  Al Ti Cr Fe Mn Mg Ca Na K  2.00  .04n  .024 .005 .254  } 2.04  1 .652 .041  Mg Fe Ca  84.80% 13.10% 2.10%  1.9471 .0537 ' 00 .015^ .004 .002 .311 }2.01 1.646 .035  2.00  2 c  Mg = 82.60% Fe = 15.65% Ca = 1.75%  2.03 1.503 .049  Ma = 75.10% Fe = 22.45% Ca•= 2.45%  1.902V oo .098/ ^ .023' .004 .022 .276 2.03 1 .604 .084 .018 2  ,uu  Mg = 81.65% Fe = 14.05% Ca-- • 4.30%  1.926 •2.00 .074, .016" .005 .746  2.00  2.05  'Z.C-2.  1 .222 .032  Mg = 61.10% Fe = 37.30% Ca = 1.60%  1 .536 .025 .002  Mg = 75.45% Fe = 23.35% Ca = 1.20%  1 .860 2.00 1 .9391 . 01 .061J .140 .066 .037^ .001 .001 .006 .342 •2.03 .280 VV2.0 1.599 1 .657 .025 .023 .002 .004j C  Mg = 81.30% Fe = 17.40% Ca = 1.30%  Mg = 84.50' Fe = 14.30! Ca = 1.20!  Si Al Ti Cr Fe Mn Mg Ca Na K  25  26  27  28  29  30  54.253 2.593 .101 .315 11 .130 n.d. 31 .270 .675  54.209 1.819 .057 .385 14.489 n.d. 28.179 1.066  55.614 2.175 .054 .032 14.267 n .d. 29.889 .919  n.d.  54.121 2.452 .156 .232 11.778 n.d. 32.071 .529 .002 n.d.  n.d.  n .d.  55.035 3.027 .035 .309 10.236 n.d. 31.484 .498 .022 n.d.  54.919 2.344 .184 .545 11.225 n.d. 30.576 .792 .059 n.d.  100.337  TOT.341  100.204  100.646  100.644  -  -  102.95  Formulae based on 6 oxygens  Oxides Si Al Al Ti Cr Fe Mn Mg Ca Na K  -  1 .912 2.00 .088 .020") .003/ .0091 . 3 2 8 \ ,03 1.642 .025 0  Mg = 82.30% Fe = 16.45% Ca = 1.25 %  1.896) .101/ .003^ .001 .0061 .345'  2  0(J ,uu  ^  2.046  1.674 .020  Mg = 82.20% Fe = 16.85% Ca = 0.95%  1-942.X . .058; .019^ .001 .011 2  ;  434  00  Jz.oi  1.505 .041  Mq = 76.05% Fe = 21.90% Ca = 2.05%  1 .933 I o 00 . 0 6 7 / ^' .022) .001 .001 .415 2.02 1.548 .034  V  J  Mg = 77.50% Fe = 20.80% Ca = 1.70%  uu  .045V .001 .008 .299 )2.01 1.638 .019 .001  Mg = 83.75% Fe = 15.30% Ca = 0.95%  }  1 .929 2 .071 .026^ .005 .015 .330  oo  Z.oi  1.601 .030 .004  Mg = 81.65% Fe = 16.85% Ca = 1.50%  MICROPROBE ANALYSIS OF CLINOPYROXENES 1 Si Al Ti Cr Fe Mn Mg Ca Na K  2  3  4 52.87 2.60 .40 .31 4.53 n.d. 16.01 21.29 .20' n.d. 98.21  54.00 3.52 " .45 .58 4.64 n.d. 16.80 21.69 .39 n.d.  52.11 2.97 .50 .39 4.92 n.d. 17.06 22.47 .46 n.d.  52.47. 3.66 .58 .36 5.04 n.d. 15.72 23.87 .57 n.d.  101.07  100.88  102.27  8  9  10  11  51.918 2.472 .402 .503 5.052 n.d. 16.625 22.381 .364 n.d.  53.19 1.37 .28 .32 4.63 n.d. 16.46 22.74 .31 n.d.  53.803 3.109 .344 .528 4.961 .093 18.106 19.456 .394  54.175 2.890 .453 .580 4.678 .060 17.778 18.483 .447  53.937 1 .902 .288 .609 3.761 n.d. 17.242 23.537 .315  100.717  99.30  100.794  99.544  102.491  -  -  Formulae based on 6 Oxygens  Oxides Si Al AT Ti Cr Fe Mn Mg Ca Na K  7 •  ]  ; 9 $ 2. ooo .064" .012 .017 • >2.003 .904 .839 .027 140  7  Mg = 48.00 Fe = 4.45 Ca = 44.55  Mg = 47.50 Fe = 7.65 Ca = 44.85  .00  2.00  2.03  1.98 .884 .845 .014  Mg = 43.95 Fe = 7.90 Ca = 48.15  1.914-1 .086/ .020 .011 .014 .156 .914 .884 .026  2  Q 0  ^'  UU  r2.02  )  1 .961 2.00 .039 .020^ .008 .009 .143 ' >2.005 .905 .898 J  Mg = 47.25% Mg = 46.80% Mg = 46.40 Fe = 7.50% Fe •= 8.00% Fe = 7.55 Ca = 45.25% Ca = 45.20% Ca = 4 6 . 0 5  1.9641 .036/ .087' .012 .017 .142 .002 .961 .718 .031  2.00  1.97  Mg = 5195% Mg = 52.75% Fe = 7.95% Fe = 7.80% Ca = 40.10% Ca = 39.45%  1 .941 .059 .022 .008 .017 .113  •2.0V  .925\ .907 .022  Mg = 47.60% Fe = 5.80% Ca = 46.60%  cont'd.  72  16  15 Si Al Ti Cr Fe Mn Mg Ca Na K  17  18  19  22  25  27  28  51.768 2.109 .466 .504 6.019 n.d. 16.859 22.447 .344 n.d.  52.24 2.06 .16 .95 4.23 n.d. 18.22 20.88 .49 n.d.  54.027 1.803 .054 .697 3.857 n.d. 18.260 22.690 .194 n.d.  53.663 2.167 .100 .738 4.503 n.d. 17.645 22.800 .294 n.d.  50.783 3.913 .359 .201 6.479 n.d. 15.547 21.270 .393 n.d.  53.007 3.503 .483 .086 6.882 n.d. 16.020 21.681 .504 n.d.  52.207 3.786 .308 .660 4.285 n.d. 17.541 22.009 .486 n.d.  52.253 2.792 .348 .382 5.926 n.d. 15.474 22.422 .435 n.d.  52.361 3.039 .381 .289 5.631 n.d. 16.543 23.291 .337 n.d.  100.517  99.23  101.582  101.910  98.945  102.166  101.282  100.032  101.872  Formulae based on 6 Oxygen s  Ixides Si Al Ti Al • Ti Cr Fe Mn Mg Ca Na. K  1 .904W 2.00 .091 J .005^  1 .940 .060. 2.00  1  -  .006/ .015 .1851 n.d. \ 2.04 .924 .885 .024 n.d. /  Mg = 46.35% Fe = 9.30% Ca = 44.35%  .03  Mg = 51.15 Fe = 6.70 Ca = 42.15  .016^ .001 .019 .116 n.d. .977 .873 I .013 \ n.d. /  01  2.00  2.022  Mg = 49.70% •Mg = 48.25% Fe = 6.90% Fe = 5. Ca = 44.85% Ca = 44.<  1 .892*1 .108 J 2.00  .911 .089 2.000  .064^ .010 .006 .202 n.d .863 ( 2.02 .849 \ .028 n.d.y Mg = 45.10% Fe = 10.55% Ca = 44.35%  ,00  .060]  .013 .002 .207 n.d .861 '2.01 .8381 .035 ] n.d. / •  Mg Fe Ca  .03  1.9241 f 2.00 .076 J  1.897C .103/ 2.00  .045^ .009 .011 .182  .027^ .010 .008 .171  .849 V 2.01 .885 .031  .893 .2.04 .904 .024  J  45.00% Mg = 49.05% Mg = 44.35% 10.80% Fe = 6.70% Fe = 9.45% 44.20% Ca = 44.25% Ca = 46.20%  Mg Fe Ca  45.40% 8.70% 45.90%  MICROPROBE ANALYSIS OF OLIVINES  Si Al Ti Cr Fe Mn Mg Ca Na K  39.90  11  12  12A  13  13A  14  39.88  40.892  40.490  40.892  40.185  40.226  .033  .010  12.942 n.d. 47.235  14.002 n.d. 47.404 .004  13.251 n.d. 47.043 .004  n.d.  n.d.  n.d.  101.102  101.605  100.524  18.04  15.94  44.13  45.81  102.07  101.63  14.838 .134 45.984  .004  .004  101 .467  101.450  Formulae based on 4 oxygens  Oxides Si Al Ti Cr Fe Mn Mg Ca Na K  14.774 .147 45.650  .993  .989  1.007  .999  1.003  .988  .995  .376  .330  .288  1.692  .306 .003 1.692  .265  1.637  .304 .003 1.677  1.727  1.737  .274 n.d. 1.735  .0002  .0002  Fo = 81 Fa = 18.80%  Fo = 83.80% Fa = 16.20%  Fo = 84.60% Fa = 15.40%  :  Fo = 84.70% Fa = 15.30%  n.d. Fo = 86.65% Fa = 13.35%  Fo = 85.80% Fa = 14.20%  Fo = 86 Fa = 13  cont'd.  Si Al Ti Cr Fe Mn Mg Ca - Na K  ./2 16  17  20  23  24  26  39.460  40.143 .549  38.045 .036 .002 .089 19.791 n.d. 44.363  39.794  40.363  38.886 .020  -  .020  -  14.150 n .d. 47.130  -  .370 15.139 n.d. 45.662 .016  .040  -  15.456 n.d.. 45.654 .047  -  -  n.d.  n.d.  n.d.  n.d.  100.760  101.879  102.326  100.991  -  Oxides Si Al Ti Cr Fe Mn Mg Ca Na K  -  -  -  -  14..381  -  46.826 -  101.570  . -  29 39.347 -  .035  -  16.986 n.d. 45.512  14.724 n.d. 45.886  .002 n.d.  n.d.  101.406  99.992  -  -  Formulae based on 4 oxygens .980  -  -  .294 n.d. 1.745 -  n.d. .  Fo = 85.55% Fa = 14.45%  .988 .016  -  .007 .312 n.d. 1.676  -  • -  n.d.  Fo = 84.30% Fa = -15.70%  .957 .001  -  .002 .416 -n.d. 1.664 -  -n .d.  Mg = 80. 0% Fe = 20. 0%  .991  -  .973  .993  .001  -  .322 n.d. 1.694 .001  .296 1.717  -  .355  .309  -  1 .698  -  n.d.  Fo = 84.0% Fa = 16.0%  •  Fo = 85.40% Fa = 14.60%  .987  -  Fo = 82.70% Fa = 17.30%  -  1.716  -  Fo = 84 Fa = 15  Appendix 5 Microprobe A n a l y s e s of  Sulfides  SULFIDE SAMPLE Mo. CORRELATION  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 15 17 18 19 20 21 22 23 24 25 26 27 28 • 29  • =•• = = = = / = = =• = = = . .= = = = = = = '= = = = = = = = ' = =  26A 28A-2 32A-1 34A-1 36A-3 41A-1 43A-1 44A-1 46A-1 47A-1 90A-1 92A-1 87A 85A 82A-1 78A-1 104A 106A 108A 114A 121A 130A-1 132A-1 140A-1 152A-1 156A-1 157A-1 160A-2 162A-1  ELECTRON MICROPROBE ANALYSES OF PENTLANDITE AND PYRRHOTITE  P e n t l a n d i t e Wt% Fe Ni Cu Co S  P e n t l a n d i t e At% Fe Ni Cu Co S Pyrrhotite  28.77 27.31  29.99 33.53 .02 2.85 33.61  27.30 28.70 .02 3.41 40.56  28.41 28.90 .03 5.30 37.36  30.55 32.16 .03 3.86 33.40  27.29 31.09 .01 7.22 34.38  30.17 33.91 .02 1.86 34.04  21 .25 21 .25 .02 2.51 54.98  22.55 21.81 3.98 51.64  24.84 24.87 .02 2.97 47.29  22.08 23.93  1.47 56.31  24.35 25.90 .01 2.19 47.54  5.54 48.45  24.43 26.12 .01 1.43 48.01  53.53 .17  59.42 .55  55.26 .28  57.17 .28  60.39 .68  58.11 .66  58.90 .37  46.31  40.02  44.46  42.55  .03 38.90  .08 41.15  40.73  39.84 .12  45.83 .40  43.56 .20  43.46 .20  46.88 .51  44.54 .48  45.24 .27  60.04  53.76  56.34  56.34  .02 52.59  .05 54.92  54.49  2.01 41 .91  22.19 20.04  Wt% Fe Mi Cu Co S  Pyrrhotite A t % Fe Ni Cu Co S  cont'd..  .11  10  11  12  13  14  Pentlandite Wt% Fe Ni Cu Co S  31.04 34.80 .04 .62 33.50  31.17 34.63 ..04 .68 33.49  30.25 35.29 . .56 33.90  31.90 35.39 .54 32.17  33.42 31.13 .04 .59 34.81  38.97 25.44 .77 34.82  39.25 25.20 01 *71 34.82  25.21 26.89 .03 .48 47.40  25.32 26.76 .03 .53 47.37  24.52 27.20 .43 47.85  26.13 27.57 . .42 45.89  26.90 23.83 .03 .45 48.80  31.29 19.43 .59 .59 48.70  31.51 19.24  59.03 .40 .01 40.56  59.48 .52 .18 39.82  57.91 1.26 40.82  61.11 .68 38.20  59.16 .22 .01 40.60  62.24 .01 - • 37.75  62.28 .01  ' 45.38 .29  45.93 .38 .12  44.47 .92  47.63 .51  45.48 .16 .01  48.67  48.67  Pentlandite At% Fe Ni Cu Co S Pyrrhotite  Wt% Fe Ni Cu Co S  Pyrrhotite  .54 48.69  37.71  \t%  Fe Ni Cu Co S  -.01  54.32  53.96  •  -  54.60  -  51.86  -  54.35  -  51.32  —  _  51 .32  cont'd.  • /3 15  16  17  18  19  20  29.76 33.15 1.78 35.29  34.78 30.37 1.43 33.42  35.06 26.71 .03 1.29 36.92  29.85 33.25  28.13 32.90  2.06 34.83  4.32 34.66  40.22 25.00 .08 .82 33.88  23.91 25.34 1.36 49.39  28.23 23.44 1.10 47.23  27.82 20.17 .02 .97 51.03  24.05 25.49  22.71 25.26  1 .57 48.89  3.30 48.73  58.20 .41 41.39  63.70 36.29  59.50 .01 .03 40.46  59.05 .46  57.91 .55  .02 40.47  .02 41 .52  44.54 .30 -  50.19 -  45.76 .01 .02  45.43 .34  44.28 .40  55.16  49.81  54.24  .01 54.22  .02 55.30  21  Pentlandite Wt% Fe Ni Cu Co S  I.A.  Pentlandite At% Fe Ni Cu Co S Pyrrhotite  32.47 19.20 .06 .63 47.64  .A.  Wt% Fe Ni Cu Co S  62.54  37.46  59.19 .40 .07 40.33  Pyrrhotite At% Fe Ni Cu Co S  48.94  51.05  45.57 .30 .05 54.08  cont'd..  ./4 22  23  24  25  25  27  28  29  28.89 33.04  31.35 32.58  28.39 34.34  31.11 33.74  3.78 34.29  1 .87 34.21  30.06 33.29 .01 1.86 34.79  3.00 34.27  .53 34.62  27.60 30.90 .04 5.85 35.61  30.49 35.14 .06 .29 34.03  30.06 34.84 .08 .43 34.59  23.27 25.43  25.34 25.05  2.90 48.31  24.68 27.06 .04 .22 47.99  24.25 26.74 .06 .33 48.62  Pentlandite Wt% Ni  Cu Co S  Pentlandite At% Fe Ni Cu Co S  Pyrrhotite  22.97 26.43  25.09 25.88  22.15 23.59  1.43 48.17  24.22 25.52 .01 1.42 48.83  2.30 48.30  .40 48.63  4.45 49.78  58.36 .66  59.94 .35.  58.89 .42  57.84 1 .05  59.25 .81  59.05 .60  57.40 .57 .02  40.97  39.70  40.69  41.11  39.94  58.34 .56 .12 .06 40.92  40.34  42.01  44.77 .48  46.31 .26  45.25 .31  44.34. .76  45.72 .59  45.46 .44  43.77 .41 .01  54.75  53.43  54.44  54.89  53.69  44.71 .41 .08 .05 54.69  54.09  55.80  Wt% Fe Mi Cu Co S  Pyrrhotite At% Fe Ni Cu . Co S  Appendix 6 U n i v e r s a l Stage C o m p o s i t i o n D e t e r m i n a t i o n s Sample No. 26A 28A-2 30A-1 32A-1 34A-1 3 6 A-3 41A-1 42A-1 43A-1 44A 46A-1 47A-1 76A-1 78A-1 82A-1 85A 87A 89A 90A-1 92A-1 104A 106A 108A 114A 120A 121A 126A-1 130A-1 131A-2 132A 135A-1 138A-2 140A 1.56A-1 159A 160A-2 162A  O/pxn (En) 82 80 82 83 82 80 82 82 84 82 84 86 88 81 87 84 87 87 92 86 86 84 86 82 82 81 82 81 82 85 87 82 82 84 86  C/pxn  (Ca:Mg:Fe)  Olivine  46:44:10 45:45:10 44:48:8 45:45:10 44:46:10 44:47:9 43:52:5 44:48:8 44:48:8 45:45:10 42:53:5 42:47:11 44:50:6 -. 45:43:12 45:45:10  45:45:10 44:48:8 -  44:46:10 -  --  —  -  -  -  ••  86 87 86 80 87 79 87 85 87 85 80 87 . 79 87 80 -  -  87 -  

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