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Geology of the Haggart Creek-Dublin Gulch Area, Mayo district, Yukon Territory. Tempelman-Kluit, Dirk Jacob 1964

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GEOLOGY OF THE HAGGART CREEK DUBLIN GULCH AREA Mayo D i s t r i c t , Yukon T e r r i t o r y  DIRK JACOB TEMPELMAN-KLUIT B . A . S c , U n i v e r s i t y o f B r i t i s h Columbia, 1962.  A. THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE  i n the Department of GEOLOGICAL ENGINEERING  We a c c e p t t h i s t h e s i s as conforming t o the required standard  THE UNIVERSITY OF BRITISH COLUMBIA March, 1964  In presenting the  requirements  British  Columbia,  available mission  for  for  for  I  agree  reference  extensive  representatives.  cation  of t h i s  thesis  an a d v a n c e d  thesis  that  and s t u d y .  by the  It  is  for  in partial  degree  the  c o p y i n g of  p u r p o s e s may b e . g r a n t e d his  this  Department  of  7 ^ 7 ^  I  this  further thesis  agree for  that  understood  A  v  per-  or by  t h a t , c o p y i n g or  f i n a n c i a l g a i n s h a l l not  k ft "**J  freely  scholarly  Head o f my Department  The U n i v e r s i t y o f B r i t i s h C o l u m b i a , V a n c o u v e r 8, Canada Date  the U n i v e r s i t y o f  L i b r a r y s h a l l make i t  w i t h o u t my w r i t t e n p e r m i s s i o n *  0  at  f u l f i l m e n t of  publi-  be a l l o w e d  ABSTRACT  The that  a r e a i s a f o u r m i l e s by  extends westward from the  centre Y.T. the  map  o f t h e map  area l i e s  ten miles  summit o f P o t a t o  about  strip  Hills.  t h i r t y miles north  The  o f Mayo,  E x p o s u r e i s p o o r i n many p a r t s o f t h e a r e a , b e c a u s e thick Pleistocene  The  rocks  contains interbedded schist plane  f a c i e s ) has  cover.  i n the  c a m b r i a n Yukon G r o u p .  area  are  q u a r t z i t e s of the  pre-  Q u a r t z i t e i s g e n e r a l l y micaceous phyllite.  affected  f o l i a t i o n has  of  R e g i o n a l metamorphism  these  been m o d i f i e d  rocks. by  two  An  early  distinct  and  (green-  bedding phases  of  folding.  A granodiorite stock with composition  has  i n t r u d e d the m e t a m o r p h i c  hundred f e e t  wide t h e r m a l  corundum h a s  been developed  the  related  sills  of  similar  a s s e m b l a g e and  metamorphic a u r e o l e  that  a  five  contains  i n the metasedimentary r o c k s  around  stock.  East disrupted  the  t r e n d i n g and  l a t e r north  have  rocks.  Mineralization  i n the  Silver-lead-antimony veins occur study  trending faults  of t h e i r mineralogy  area  i s of v a r i o u s  i n the west.  shows them to c o n t a i n  types.  A preliminary jamesonite,  galena,  sphalerite,  hedrite  and  include bindheimite  goethite, scorodite, covellite  Two the  pyrite,  arsenopyrite,  b o u l a n g e r i t e i n a gangue o f s i d e r i t e  Secondary m i n e r a l s site,  chalcopyrite,  stages  topography,,  and  dolomite.  or s t e t e f e l d i t e ,  and  tetra-  angle-  chalcosite.  o f P l e i s t o c e n e i c e a d v a n c e have m o d i f i e d  Frontispiece.  P e s o S i l v e r M i n e s Camp and a d i t t o number One v e i n c r o s s c u t i n foreground. Galena H i l l i n middle background. D a v i d s o n range i n f a r background. O v e r c a s t weather i s t y p i c a l f o r the a r e a d u r i n g summer, looking southeast.  CONTENTS Page INTRODUCTION.  1  L o c a t i o n and A c c e s s  2  P h y s i o g r a p h y , Topography and C l i m a t e  2  P r e v i o u s G e o l o g i c a l Work  3  Acknowledgments  4  Mining History  5  Glaciation  6  GEOLOGY OF THE AREA  9  G e n e r a l Statement Metamorphic  Rocks  9 12  Medium t o dark grey massive q u a r t z i t e  12  Medium t o l i g h t grey massive q u a r t z i t e  14  Green and Maroon P h y l l i t e s .  14  Micaceous Q u a r t z i t e  15  Grey P h y l l i t e  17  Andalusite Hornfels  19  Quartz D i o p s i d e H o r n f e l s  21 i  I n t r u s i v e Rocks B i o t i t e Quartz D i o r i t e  2,4 24  Petrology  24  Structure  32  O r i g i n and Mode o f Emplacement  33  Quartz F e l d s p a r P o r p h y r y  3^  P o r p h y r i t i c Amygdaloidal Basalt  35  Page Augitite  37  STRUCTURAL GEOLOGY  ^0  G e n e r a l Statement  40  Minor Structures  4l  Foliation  4l  Lineation  43  Minor Folds  44  Joints  47  Conclusions  48  Major Structures  51  Folds  51  Faults  52  a.  H a g g a r t Creek F a u l t  53  b.  Tin H i l l Fault.  5^  c.  Black P h y l l i t e F a u l t  5^  d.  Rex F a u l t  55  e.  F i f t e e n Pup C r o s s f a u l t  56  f.  S e c r e t Creek F a u l t  56"  g.  McGann Creek F a u l t  57  Tectonic H i s t o r y S t r u c t u r a l F i t with Patterns Some Ideas METAMORPHISM  57 t o the S o u t h : 58 60  G e n e r a l Statement  60  R e g i o n a l Metamorphism  6l  Thermal Metamorphism..  62  Metasomatism  67  Page Temperatures  and P r e s s u r e s D u r i n g Metamorphism....  67 68  Age R e l a t i o n s ANTIMONY SILVER LEAD .VEINS  69  General Statement  69  Number One V e i n  71  Textures  73  Secondary A l t e r a t i o n  76  Paragenesis  77  Temperature  o f D e p o s i t i o n and C l a s s i f i c a t i o n . . .  78 78  Number Two V e i n . Textures  79  Secondary A l t e r a t i o n  80  Paragenesis  80  Temperature  o f D e p o s i t i o n and C l a s s i f i c a t i o n . . .  80 81  Number T h r e e V e i n Textures  82  Secondary A l t e r a t i o n  83  Paragene s i s  83  T e m p e r a t u r e o f D e p o s i t i o n a.nd C l a s s i f i c a t i o n . . .  84 85  Rex V e i n Textures  86  Secondary A l t e r a t i o n  91  Paragenesis  92  Temperature o f D e p o s i t i o n and C l a s s i f i c a t i o n . . .  93  Z o n i n g o f • the D e p o s i t s Time o f E m p l a c e m e n t  of Vein Minerals  SUMMARY OE GEOLOGIC HISTORY  9^ .94 96  ILLUSTRATIONS  Facing Page  Figure Frontispiece Peso S i l v e r Mines Camp, a d i t to number One v e i n c r o s s c u t , Galena H i l l and Davidson Range... 1.  Index map  2.  Looking east up the v a l l e y of D u b l i n Gulch a t Potato H i l l s  k  3.  Looking e a s t down the v a l l e y of F i s h e r Gulch a t T i n H i l l , Potato H i l l s and Lynx Dome  5  4..  to show l o c a t i o n and access  2;  Knot of k a o l i n i t e and l i m o n i t e surrounded f l a k e s of muscovite i n massive q u a r t z i t e  by 13  5.  Micaceous q u a r t z i t e cut p e r p e n d i c u l a r to l i n e a t i o n and f o l i a t i o n  15  6.  Folded muscovite  18  7.  Grey p h y l l i t e cut p e r p e n d i c u l a r to f o l i a t i o n and l i n e a t i o n . .  18  8.  A n d a l u s i t e h o r n f e l s c u t p e r p e n d i c u l a r to f o l i a t i o n and l i n e a t i o n . . .  19  9.  C r o s s - s e c t i o n of euhedral a n d a l u s i t e c r y s t a l showing the p l e o c h r o i c core  20  10.  Anhedral a l t e r e d a n d a l u s i t e prism i n a n d a l u s i t e hornfels  20  11.  Anhedral g r a i n s of corundum i n a groundmass of micas and quartz  21  12.  B l u f f s west of Ray  22  13.  D i o p s i d e i n quartz  23  14.  Quartz D i o p s i d e h o r n f e l s  23  15.  A zoned p l a g i o c l a s e g r a i n  25  16.  P o r p h y r i t i c b i o t i t e quartz monzonite of p l a g i o c l a s e , quartz and b i o t i t e  bands i n grey p h y l l i t e  Gulch  phenocrysts 25  Facing Page  Figure 17.  Medium g r a i n e d  biotite  18.  P a r t l y a l t e r e d p o r p h y r i t i c gabbroic quartz d i o r i t e  19.  P a r t l y a l t e r e d gabbroic  20.  Strongly  26  granodiorite biotite  2 7 27  biotite  a l t e r e d gabbroic  biotite  quartz 29  diorite 21.  Foliation  at contact  22.  C o n t o u r s on u p p e r s u r f a c e  23.  P o r p h y r i t i c amygdaloidal  24.  l a r g e phenocryst  32  of granodiorite of stock  3 3 36  basalt  of i n d i v i d u a l  rounded  grains 36  of sanidine 25.  Grain  26.  Hornblende  27.  "Checkerboard" twinning  28.  Phase  I minor f o l d s i n micaceous  29.  Poles  to f o l i a t i o n  east  o f Haggart Creek  4 2  30.  Poles  to f o l i a t i o n  west  o f Haggart Creek  4 2  31.  P o l e s t o f o l i a t i o n i n t h e number One v e i n crosscut Phase I l i n e a t i o n a n d p o l e s t o f o l i a t i o n . n o r t h of Black P h y l l i t e f a u l t  32. 33*  of d i o p s i d i c augite  3 7  i n augitite  L i n e a t i o n and p o l e s  3 7 3 7  to f o l i a t i o n  quartzite  south  4 0  4 2 4 3  o f Rex  fault  4 3  34.  Phase  I l i n e a t i o n s west  of Haggart Creek f a u l t . .  4 3  35»  Phase  I l i n e a t i o n s east  of Haggart Creek f a u l t . .  4 3  36.  Phase  I I l i n e a t i o n s west  o f Haggart Creek f a u l t .  4 3  37•  Phase  I minor f o l d s north  38,39»40.Cross-sections various  parts  o f McGann C r e e k  o f m i n o r f o l d s o f Phase  o f t h e map axes west  4 4  I from  area  41.  Phase  I fold  42.  Poles  to j o i n t s west.of Haggart Creek f a u l t  . ...  of Haggart Creek f a u l t . . .  4 5 4 6 4 7  Figure  ; -•  ;  •  '  Facing Page  43.  P o l e s t o j o i n t s e a s t o f Haggart Creek f a u l t . . . .  47  44.  Poles to j o i n t s i n g r a n i t i c rocks  48  45.  ACF diagram f o r g r e e n s c h i s t f a d e s  6l  46.  AKF diagram f o r h o rnblende h o r n f e l s f a c i e s  63  47.  ACF diagram  65  48.  Temperature and p r e s s u r e o f t h e r m a l metamorphism .  68  49.  Peso S i l v e r Mines Camp l o o k i n g n o r t h  69  50.  T e x t u r a l r e l a t i o n s h i p s of p y r i t e  73  51.  Two h a b i t s o f p y r i t e  73  52.  Coarse p r i s m a t i c g r a i n s o f j a m e s o n i t e  74.-  53.  S i d e r i t e c o n t r o l l e d g o e t h i t e boxworks  77  54.  Number One v e i n p a r a g e n e s i s  78  55«  A r s e n o - p y r i t e i n jamesonite-,-.....  79  56.  Number Two v e i n p a r a g e n e s i s  80  57.  P y r i t e i n galena  82  58.  Number Three v e i n p a r a g e n e s i s  83  59.  S p h a l e r i t e i n jamesonite  87  Siderite f i l l e d fracture i n tetrahedrite  87  61.  Jamesonite  and t e t r a h e d r i t e i n c o n t a c t  88  62.  Jamesonite  l a t h s e n c l o s e d by s i d e r i t e  88  63.  Two h a b i t s o f j a m e s o n i t e . . . .  89  64.  Jamesonite  89  65.  Galena i n c o n t a c t w i t h d o l o m i t e  90  66.  Siderite f i l l i n g fractures i n tetrahedrite  90  67.  A l t e r a t i o n of jamesonite along f r a c t u r e s  91  68.  Rex V e i n p a r a g e n e s i s  93  60.  .  f o r h o rnblende h o r n f e l s f a c i e s  and g a l e n a i n c o n t a c t  APPENDICES  APPENDIX I  G e o l o g i c Map o f Haggart  Creek  - D u b l i n Gulch  Scale  Area  1"=1,000»  APPENDIX I I Structural Haggart  Creek  Trend  Map  - D u b l i n Gulch  Scale  Area  1:50,000  APPENDIX I I I B l o c k diagram Haldane,  o f Keno H i l l ,  Potato H i l l s  Mount  Area  1.  INTRODUCTION  The  area near Dublin  o f economic i n t e r e s t Dublin The  G u l c h and  presence  west  s i n c e the  of lode  g o l d and Hills  The  rocks and  a t i o n and  object  tends n o r t h  o f 1963  i n the  the  geologic explor-  deposits;  Hills.  lies  east  and  a few  of  I t i s bounded  V a l l e y o f L y n x and H a g g a r t C r e e k s and  summer o f 1962  area.  a  the  deposits.  square m i l e s )  to P o t a t o  in  t w o f o l d : : t o map  from t h i s boundary about three m i l e s .  spent most o f the  old  interest  antimony-silver-lead o f these  the  1920's.  s t u d i e s r e q u i r e d i n the f u r t h e r  extends east the  deposits.  G u l c h on  thus to provide  been  century.  m i n e r a l i z a t i o n on  work was  a r e a mapped ( a b o u t kO  by  this  a r o u s e d new  and  the m i n e r a l o g y  S e c r e t C r e e k and south  of  b e e n known s i n c e the  o f the p r e s e n t  development of the  t o work out  the  has  structures i n detail  The  on  tungsten  showings h a s  framework f o r d e t a i l e d  and  early part  e x p l o r a t i o n a c t i v i t y west of D u b l i n  antimony-silver-lead area.  S e c r e t Creek has  Haggart Creek c o n t a i n p l a c e r gold  side of Potato  Recent  G u l c h and  The  weeks o f t h e  ex-  writer summer  Figure  1»  I n d e x map  t o show l o c a t i o n  and  access.  2.  L o c a t i o n and Access  The of  centre  Mayo L a n d i n g ,  o f t h e map  the nearest  area l i e s  large settlement.  w e s t e r n p a r t o f t h e a r e a c a n he g a i n e d i n d e x map).  The d i s t a n c e by r o a d  area i s about f i f t y m i l e s . by  thirty miles Access  north t o the  by s e v e r a l r o u t e s ( s e e  t o Mayo f r o m  The a r e a i t s e l f  t h e w e s t end o f t h e  i s now  criss-crossed  a number o f b u l l d o z e r t r a i l s .  Physiography,  The subdivision  Topography and C l i m a t e  e n t i r e map a r e a l i e s  o f Yukon P l a t e a u .  w i t h i n Stewart  Plateau - a  The t o p o g r a p h y o f p a r t s o f t h e  Stewart  P l a t e a u h a s b e e n d e s c r i b e d by C a i r n e s  Bostock  (19390 •  O f "the Mayo a r e a , C a i r n e s  (1916) a n d  says:  "Mayo a r e a  i s m a i n l y c h a r a c t e r i z e d by b e i n g s u b d i v i d e d by w e l l d e v e l o p e d , f l a t bottomed, I n t e r l o c k i n g v a l l e y s i n t o s m a l l , i s o l a t e d mountain g r o u p s and a r e a s o f w e l l d i s s e c t e d u p l a n d The v a l l e y w a l l s have become smoothed, p l a n a t e d , and s t e e p e n e d , g i v i n g t h e v a l l e y s t y p i c a l U-shaped c r o s s e c t i o n s . I n a d d i t i o n , the f l o o r s o f the m a s t e r v a l l e y s h a v e become d e e p l y c o v e r e d w i t h g l a c i a l d e t r i t u s , w h i c h i n p o s t - g l a c i a l t i m e s h a s b e e n t r e n c h e d and i n p a r t removed by t h e s t r e a m s o f t h e d i s t r i c t . " Relief  i s moderate.  feet, while map a r e a , lie  Most r i d g e s reach  t h e summit o f P o t a t o  lies  at  5>000 f e e t .  a t a n e l e v a t i o n o f about  elevations close to  Hills,  the h i g h e s t p a r t of the  The v a l l e y s  2,500 f e e t .  4,500  o f the l a r g e  creeks  3  Large  areas of upland a r e almost  flat  and f e a t u r e l e s s  and merge g r a d u a l l y w i t h t h e s t e e p e r , b u t r e g u l a r v a l l e y  generally of  Outcrop  i s s c a r c e and g l a c i a l  thick.  Abundant  g u l c h e s and n e a r  till  outcrop i s found  the top o f the v a l l e y  are almost  and  o n l y a t t h e heads  walls.  s t e e p s i d e d r i d g e s h a v e o u t c r o p s a l o n g them. hills  widespread  walls.  Some o f t h e  The f l a t  topped  d e v o i d o f o u t c r o p and a r e c o v e r e d b y l a r g e  a r e a s o f d i s i n t e g r a t e d , moss a n d b r u s h c o v e r e d , b l o c k s o f bedrock, are  which resemble  f o r t h e most p a r t  The  felsenmeer.  l o c a l l y derived.  weather i s quite v a r i a b l e  warm w e a t h e r may c h a n g e u n e x p e c t e d l y that can l a s t cloudy. hours for  f o r d a y s o r weeks.  During  the e a r l y  o f the day:  less  i n summer.  to d r i z z l y  A s p e l l of  cool  weather  The s k y seems p e r p e t u a l l y  summer, d a y l i g h t  extends  f o r twenty  t o w a r d s t h e e n d o f summer, d a y l i g h t  than t e n hours  hot, while the h i l l t o p s temperatures  Rocks o f the " f e l s e n m e e r "  p e r day.  During  are c o o l e r .  lasts  summer t h e v a l l e y s a r e  Winters  are c o l d  commonly d i p a s l o w as 6 0 ° F b e l o w z e r o .  and d a r k , Precipi-  tation i s light.  P r e v i o u s G e o l o g i c a l Work  Although in  connection with  a c o n s i d e r a b l e amount o f work h a s b e e n done the p l a c e r d e p o s i t s a t D u b l i n G u l c h and Haggart  Figure  2.  L o o k i n g e a s t UP t h e v a l l e y o f D u b l i n G u l c h at Potato H i l l s i n background. Taken from Tin H i l l . The t o p o g r a p h y i s characteristic o f t h e map a r e a .  4.  Creek, and the l o d e Gulch,  nothing  gold,  i s published  s h o w i n g s west o f D u b l i n  Reference deposits  t i n and s c h e e l i t e concerning  the a n t i m o n y - s i l v e r - l e a d  t o the above mentioned p l a c e r and l o d e e a r l y Summary R e p o r t s o f t h e G.S.C.  by D . D . C a i r n e s , W . E . C o c k f i e l d  at  Dublin  Gulch.  i s made i n v a r i o u s  mapped t h e a r e a  deposits near  and H.S.Bostock.  i n the v i c i n i t y  a scale of 2,000'=1"  during  A considerable  of Potato  H.S.Bostock  Hills  and D u b l i n  Gulch  t h e summer o f 1 9 ^ 3 .  amount o f i n f o r m a t i o n  on t h e s i l v e r -  l e a d - a n t i m o n y m i n e r a l i z a t i o n west o f H a g g a r t Creek i s c o n t a i n e d i n unpublished  mineralographic  reports  o f Prof.R.M.Thompson by J . A . C o a t e s (1962)  a n d A.Armour-Brown  done u n d e r t h e d i r e c t i o n  (i960),  D.Tempelman-Kluit  (1963).  Acknowledgements  The the  field  w r i t e r was v e r y  t o D r . .A.E.Aho, C o n s u l t i n g  for h i s interest,  work a n d t h r o u g h o u t wish  assisted i n  by F r e d A. C a r t e r a n d J i m R. McMahon.  I am i n d e b t e d Engineer,  a b l y and w i l l i n g l y  help  and guidance  the p r e p a r a t i o n  of this  during  thesis.  to express s i n c e r e a p p r e c i a t i o n t o P r o f e s s o r  u n d e r whose d i r e c t i o n  this  t h e s i s was w r i t t e n ,  R.M.Thompson f o r h i s a d v i c e , and h e l p w i t h  Geological the f i e l d I further  K.C.McTaggart,  and t o P r o f e s s o r  t h e m i n e r a l o g i c a l work.  F i g u r e 3.  L o o k i n g e a s t down the v a l l e y of F i s h e r G u l c h at T i n H i l l i n middle foreground, Potato H i l l s i n r i g h t "background and Lynx Dome i n l e f t background. The topography i s t y p i c a l of t h a t found i n most of the map a r e a .  5.  The of  continued  interest  and g o o d w i l l o f t h e p e r s o n n e l  P e s o S i l v e r M i n e s L t d . i s v e r y much a p p r e c i a t e d .  Peso S i l v e r Mines g e n e r o u s l y of  the t h i n  of  t h e map.  s e c t i o n s , photographs,  d e f r a y e d t h e c o s t o f some  thesis  t y p i n g and d r a u g h t i n g  Mining H i s t o r y  The described  initial  by C a i r n e s  d i s c o v e r y o f g o l d on H a g g a r t C r e e k was  (1915) who  says:  " G o l d i s r e p o r t e d t o h a v e b e e n f i r s t f o u n d on H a g g a r t C r e e k i n 1895 and i n I896 t h e c r e e k i s known t o have b e e n p r o s p e c t e d by Thomas N e l s o n who f o u n d g o l d i n t h e c a n y o n f o u r t o f o u r and one h a l f m i l e s f r o m the mouth; a f t e r h i m t h e s t r e a m was named N e l s o n C r e e k . I n t h e same y e a r Thomas H a g g a r t b u i l t two c a b i n s on t h e c r e e k , and one on D u b l i n G u l c h , from w h i c h t o p r o s p e c t and m i n e . I n 1898 Thomas H a g g a r t , Thomas N e l s o n , P e t e r H a g g a r t and W a r r e n H i a t t s t a r t e d from Dawson f o r N e l s o n C r e e k , b u t e n r o u t e s e p a r a t e d i n t o two p a r t i e s , and P e t e r H a g g a r t and Warren H i a t t , r e a c h i n g t h e i r d e s t i n a t i o n f i r s t , s t a k e d D i s c o v e r y , and renamed t h e s t r e a m a f t e r P e t e r H a g g a r t . Since then there h a s e a c h y e a r b e e n more o r l e s s m i n i n g and p r o s p e c t i n g a l o n g t h e creek." Placer mining mittently of  s i n c e 1895  activity  the c r e e k  on H a g g a r t C r e e k h a s c o n t i n u e d  and i s s t i l l  was r e a c h e d  i n 1915  i n f o u r separate  carried  on t o - d a y .  when s e v e n t e e n  interA peak  men w o r k e d on  parties.  J o h n S u t t l e s , who h e l d a b o u t t w e n t y f i v e h u n d r e d near  t h e mouth o f D u b l i n G u l c h  from  I898 t o 1915,  feet  i s supposed t o  6.  have r e c o v e r e d time.  upwards o f $45,000 w o r t h o f g o l d d u r i n g  The C a n t i n b r o t h e r s  ground i n the f a l l  ( L o u i s and Prank) a c q u i r e d  o f 1915  and c o n t i n u e d  that Sutties'  t o mine t h e c r e e k  until  t h e 1920's, when i n t e r e s t waned and t h e g r o u n d l a y i d l e .  Not  until  1916 was t h e v a l u e  of the s c h e e l i t e  was p i c k e d up i n t h e p l a c e r c o n c e n t r a t e s this  time  the s c h e e l i t e has been saved I n 1936 E d B a r k e r  Creek below D u b l i n Gulch, mile  o f Dublin Gulch  Taylor.  In the e a r l i e r p r o s p e c t i n g f o r the lode  and s h i p p e d .  Fred T a y l o r staked  and E . B l e i l e r  Fred T a y l o r s t i l l  r e a l i z e d and s i n c e  and George P o t t e r s t a k e d  while  and H. Seaholm s t a k e d  of p l a c e r mining  source  Haggart  the f i r s t  works h i s g r o u n d on D u b l i n  years  the form  of d r i f t s )  above  Gulch.  considerable  o f the p l a c e r g o l d l e d to the  d i s c o v e r y o f a number o f s m a l l , s t r o n g l y o x i d i z e d , g o l d arsenopyrite veins.  which  bearing  A c o n s i d e r a b l e amount o f work ( m a i n l y i n was done on some o f t h e s e  No s h i p m e n t s were e v e r made f r o m w o r k i n g s a r e now c a v e d  or f u l l  any o f t h e s e  veins before showings.  1918.  Most  of ice.  Glaciation  The briefly  glacial  f e a t u r e s and h i s t o r y  d e s c r i b e d by Bostock  (1939)  (1943)  o f t h e a r e a have (1947)  been  and C a i r n e s  7  (1915)  (1916),  McTaggart  (i960).  B o s t o c k (1943) c o n s i d e r s t h a t " t h e map a r e a o c c u p i e s p a r t of a d i s t r i c t i n w h i c h t h e g l a c i e r s f o r m e d d u r i n g the l a s t , m a i n s t a g e o f P l e i s t o c e n e g l a c i a t i o n w a s t e d away D u b l i n Gulch and H a g g a r t C r e e k a r e b e l i e v e d t o have b e e n p r o t e c t e d f r o m t h i s l a s t g l a c i a l a d v a n c e b y t h e h i l l s to t h e e a s t , b u t t h e r e i s e v i dence i n D u b l i n G u l c h o f a n e a r l i e r s t a g e o f P l e i s t o c e n e g l a c i a t i o n d u r i n g w h i c h t h e i c e r o s e much h i g h e r t h a n d u r i n g t h e l a s t stage."  The form  of t i l l  evidence banks,  s u p p o r t i n g the f i r s t  s c o u r marks, d r u m l i n s ,  outwash f e a t u r e s , t h e d i s p o s i t i o n upper l i m i t  o f the l a s t  off  i n this  of  rapidly  stage  statement  i s i n the  kame t e r r a c e s a n d  o f which suggest  that the  of Pleistocene glaciation  dropped  a r e a w h i c h must have b e e n c l o s e t o t h e m a r g i n  maximum s o u t h w e s t w a r d a d v a n c e  o f i c e o f the l a s t P l e i s t o c e n e  period. Evidence stage of  f o r the second  o f i c e advance  D u b l i n Gulch.  statement  d u r i n g the P l e i s t o c e n e i s found  Here a w e l l developed,  mantles a thick l a y e r  of t i l l ,  crumbly  and some s t r i a t e d  foreign rocks  A weathered t i l l associated with  the l a s t  phenomena a r e t h o u g h t occurred occurs  earlier  concerning  i n the v a l l e y  thick  soil  w h i c h c o n t a i n s many w e a t h e r e d a n d andesitic  and w e l l d e v e l o p e d  stage  of glaciation  to indicate  soil  to the south.  boulders.  are n o t found  and h e n c e  that g l a c i a t i o n  i n the P l e i s t o c e n e than  i n McQuesten v a l l e y  two f e e t  an e a r l i e r  these  i n this  t h a t whose f r e s h  area debris  8  Evidence area  that  west o f D u b l i n  elevation  of four  Creek a r e thought  the o l d e r g l a c i a l  Gulch i s scanty.  advance c o v e r e d the  Glacial  striae  t h o u s a n d f e e t on t h e r i d g e n o r t h  a t an  of Carter  to belong  to the o l d e r g l a c i a l  stage.  e r r a t i c s , mostly of d i o r i t e  are scattered across  the area.  some p l a c e s is  found  a well  developed  soil,  o v e r l y i n g a weathered  In general  as much a s two f e e t  evidence  i s l a c k i n g , whereas i t i s q u i t e w e l l  later  glacial  McTaggart  (i960)  preserved  i s due t o a l o n g  time i n t e r v a l  glacial  f o r the  has suggested  d i f f e r e n c e i n the state o f p r e s e r v a t i o n  features  thick,  f o r the e a r l y  stage  this  In  till.  topographic  advance.  A few  of  that  topographic  between t h e two  glacial  episodes.  While show no s i g n s glacial last  probably Dublin  of having  advance  stage  t h e v a l l e y s o f H a g g a r t C r e e k and D u b l i n  ( s i n c e none o f t h e f e a t u r e s  of glaciation  i s present,  Gulch) the v a l l e y o f Secret  subsidiary  a soil,  scouring  which would  i s found i n  C r e e k t o t h e west does have a  o f i t s w e s t bank and i t i s t h o u g h t  i c e tongue may h a v e l a i n  Permafrost  the l a s t  a s s o c i a t e d with the  and s i n c e  have b e e n removed by l a t e r g l a c i a l  kame t e r r a c e on p a r t s  slopes,  been i n v a d e d by i c e d u r i n g  Gulch  that a  i n i t s valley.  i s not r e s t r i c t e d  to the north  although i t i s encountered nearer  dipping  t o the s u r f a c e  here  9. t h a n i t i s on the s o u t h e r n s l o p e s . frost but  extends  The d e p t h t o w h i c h  i s n o t known w i t h much c e r t a i n t y  perma-  i n t h i s area,  u n f r o z e n g r o u n d h a s n o t b e e n r e a c h e d a t a d e p t h o f one  hundred  and f i f t y  Galena H i l l s , f o u r hundred  i n underground  permafrost extends  workings.  to depths  On Keno and  o f two h u n d r e d t o  feet.  Stone flat  feet  stripes  top of Potato H i l l s  and r o c k p o l y g o n s a r e f o u n d o n l y on t h e and even here  they are poorly  developed.  GEOLOGY OP THE AREA  GENERAL  STATEMENT  A  thick  sequence  o f w e a k l y metamorphosed, n o n - f o s s i l i -  ferous,  sedimentary rocks u n d e r l i e s  is  t o be o f P r e c a m b r i a n  said  t h e map  and/or Cambrian  and b e l o n g s t o B o s t o c k ' s Yukon Group. not  determined w i t h i n  known.  Beds a p p e a r  The m e t a m o r p h i c Mesozoic,  bottom  age.  sequence  age ( G r e e n  19&2)  t o p s were  r e l a t i v e ages  are not  i n t h e n o r t h t h a n i n the s o u t h .  h a s been i n t r u d e d by g r a n o d i o r i t i c  rocks  C r e t a c e o u s age ( G r e e n 1 9 6 2 )  and by b a s a l t i c  Cemented g r a v e l  age o c c u r s n e a r t h e  o f some v a l l e y s .  alluvial  The  Stratigraphic  a r e a so t h a t  t o be y o u n g e r  sequence  perhaps  of T e r t i a r y  t h e map  area.  d e p o s i t s mantle  of T e r t i a r y  rocks  Q u a r t e r n a r y u n c o n s o l i d a t e d g l a c i a l and the h i l l s i d e s to e l e v a t i o n s  of t h i r t y -  10  f i v e hundred f e e t .  The f o l l o w i n g  t a b l e shows these r e l a t i o n -  ships more c l e a r l y . ERA  PERIOD  LITHOLOGY  Quarternary  U n c o n s o l i d a t e d g l a c i a l and a l l u v i a l deposits Cemented g r a v e l - u n c o n s o l i d a t e d  CENOZOIC Tertiary  • P o r p h y r i t i c amygdaloidal Quartz and/or f e l d s p a r  MESOZOIC  Cretaceous Precambrian and/or Cambrian The  basalt  porphyry  Medium g r a i n e d b i o t i t e  granodiorite  Micaceous q u a r t z i t e s , p h y l l i t e s , massive f e l d s p a t h i c q u a r t z i t e s . YUKON GROUP  p r e s e n t study concerns the Yukon group.  Although  the Yukon group has been known f o r many years and i s w i d e l y d i s t r i b u t e d i n c e n t r a l Yukon, l i t t l e stratigraphy,  i s known of i t s i n t e r n a l  because i t i s s t r u c t u r a l l y complex and crops out  poorly. A d e s c r i p t i o n o f the s t r u c t u r a l sequence i s r e s o r t e d to since  the s t r a t i g r a p h i c s u c c e s s i o n i s not known. The  following  s u c c e s s i o n of metamorphic rocks from  n o r t h (youngest) to south ( o l d e s t ) has been 1.  Massive grey q u a r t z i t e - g e n e r a l l y ,  established. thought not  u n i v e r s a l l y s l i g h t l y f e l d s p a t h i c - with b l a c k carbonaceous p h y l l i t e and minor interbedded b l a c k i n pure limestone.  11  I n the that  south  o f t h e map  contain interbedded  thought basis  t o be  green  and  area are s i m i l a r q u a r t z i t e s maroon p h y l l i t e , w h i c h  the u p f a u l t e d c o r r e l a t i v e  of s i m i l a r  of t h i s u n i t  on  the  lithology.  2.  Micaceous  quartzite with  interbedded  grey  3•  Phyllitic  quartzite with  interbedded  andalusite  fels  (metamorphosed e q u i v a l e n t o f g r e y  side  h o r n f e l s and  lents  unit  quartz  on Keno and  fault  map  the n o r t h  are  t o be  Galena  The p a r t by  the  lithology,  correlative  lower  o f t h e Upper  an  e a s t e r n and  o f t h e map  f e a t u r e s i n the  h i s t o r y has  r e g i o n a l metamorphism has  rocks  i n the  East to the  a r e a have b e e n a f f e c t e d eastern part  been s i m i l a r  diop-  equiva-  or  last  Schist  are  the h i g h e s t r o c k s .  affected  these  east block  a western of  this  northwest. by  contact  indicate  to t h a t i n the w e s t .  to the n o r t h e a s t a t moderate to s h a l l o w  The  the  rocks which dip moderately  West o f H a g g a r t C r e e k f a u l t are  (metamorphosed  t r e n d i n g Haggart Creek f a u l t .  Structural  tectonic  quartz  horn-  marble.  area i s divided into  the l o w e s t  metamorphism.  the  phyllite.  Hills.  Rocks i n t h i s h a l f  that  and  the b a s i s of s i m i l a r  i s considered  phyllite),  diopside skarn  o f impure l i m e s t o n e )  On  are  angles.  Dips  here  Only  weak  rocks.  c a n be  divided into  two  12  major groups whose c o n t a c t i s a p p a r e n t l y c o n f o r m a b l e .  I n the  southeast corner o f the area are q u a r t z i t e s w i t h limey i n t e r b e d s , w h i l e t h e r o c k s i n the n o r t h w e s t  c o r n e r o f t h i s b l o c k a r e non-  c a l c a r e o u s q u a r t z i t e s and p h y l l i t e s .  The b l o c k has been i n t r u d e d by  a g r a n o d i o r i t e s t o c k which o c c u p i e s i t s c e n t e r .  Thermalmetamor-  phism has a f f e c t e d t h e r o c k s n e a r the g r a n o d i o r i t e c o n t a c t . f  The w e s t e r n b l o c k c a n be d i v i d e d i n t o t h r e e r o u g h l y east-west  areas on t h e b a s i s o f l i t h o l o g y .  The northernmost o f  these areas i s made up o f f a i r l y massive g r e y f e l d s p a t h i c q u a r t zite.  The m i d d l e a r e a c o n s i s t s o f micaceous q u a r t z i t e s and  phyllites. formable  The c o n t a c t between t h e northernmost bands i s con-  i n the west and unconformable i n the e a s t .  a r e a i s s e p a r a t e d by the n o r t h e r n ones by a f a u l t .  The s o u t h e r n Rocks i n t h e  s o u t h e r n band a r e m i c a c e o u s , f e l d s p a t h i c q u a r t z i t e s and p h y l l i t e s . I n t r u s i v e rocks i n t h i s block are l i m i t e d  to s i l l s of d i o r i t e r e -  l a t e d t o t h e s t o c k i n t h e e a s t b l o c k and dykes o f q u a r t z f e l d s p a r porphyry  as w e l l as p o r p h y r i t i c b a s a l t .  METAMORPHIC ROCKS Medium t o dark grey massive q u a r t z i t e Grey q u a r t z i t e c r o p s o u t south o f Rex f a u l t and west o f Haggart Creek f a u l t .  Maroon and green p h y l l i t e s and p h y l l i t i c  q u a r t z i t e s d e s c r i b e d s e p a r a t e l y occur interbedded w i t h i t .  I j  Figure  4,  Knot of k a o l i n i t e and l i m o n i t e flakes of muscovite i n massive X-Hicols. x ^5.  surrounded quartzite  by  13  Quartzite  outcrops  are w e l l j o i n t e d  foliation  and l i n e a t i o n .  The q u a r t z i t e  c o l o u r and h a s a ' s i l i c e o u s ' equant white  r o c k c o n t a i n s more  muscovite,  while kaolin,  remainder.  Grain size  texture  i s distinctly  Quartz  roughly  across.  t h a n 90$ q u a r t z and a b o u t  and a b o u t  5$  . 2;.:mm., t h e o v e r a l l  granoblistic.  irregularly  shaped g r a i n s , which  orientation parallel  to f o l i a t i o n .  o f l a r g e g r a i n s (4 mm.)  A  of quartz of  equant shapes a r e s c a t t e r e d randomly  through  rock.  Muscovite segregated  flakes  i n thin  occur  layers  Roughly equant knots kaolinite  (checked  a b o u t 2 mm. ing  with  q u a r t z shows s t r o n g l a m e l l a r and i r r e g u l a r e x t i n c t i o n .  various  and  o f i t i s studded  f e l d s p a r up t o 5 mm.  i s uniform  occurs i n very  s m a l l p r o p o r t i o n (5)  the  Much  i s medium g r e y i n  l i m o n i t e and s c h o r l i t e make up t h e  have a p o o r p r e f e r r e d f o r m The  look.  grains of k a o l i n i z e d  The  b u t g e n e r a l l y show a p o o r  across  by X - r a y  s c a t t e r e d through  the rock  t h a t define the f o l i a t i o n .  o r aggregates  of very f i n e  powder method) a n d l i m i n i t e k n o t s a r e  and commonly h a v e m u s c o v i t e  flakes  surround-  them.  Schorlite through  the rock.  grained  i s i n anhedral  grains scattered evenly  14  Medium t o l i g h t  grey massive  The m a s s i v e map a r e a a r e s i m i l a r grey q u a r t z i t e s quartzites. northern  quartzites  i n the n o r t h e r n p a r t o f the  to those which o c c u r i n the south.  a r e darker i n c o l o u r than a r e southern  Phyllitie  quartzite  interbeds are l e s s  than  i n the south.  A few t h i n  s e c t i o n such  i n the  black p h y l l i t e s are  content.  discontinuous interbeds of black,  aceous and m i c a c e o u s l i m e s t o n e  G r e e n and maroon  grey  a n d m a r o o n c o l o u r s o f i n t e r b e d d e d phy-  In t h i n  marked b y t h e i r c a r b o n  plentiful  Northern  t h e y a r e i n t h e s o u t h and t h e y a r e b l a c k  i n c o n t r a s t to the green llites  quartzite  occur i n the black  carbon-  phyllites.  phyllites  G r e e n a n d maroon p h y l l i t e s make up a s m a l l p a r t o f the exposed s o u t h e r n prominent  grey  i n the v i c i n i t y  quartzite unit o f Rex v e i n .  This rock type cannot from  grey p h y l l i t e .  but are p a r t i c u l a r l y  be d i s t i n g u i s h e d  microscopically  A d i s t i n c t i o n c a n be made i n t h e f i e l d on  the b a s i s o f t h e c o l o u r o f t h e r o c k .  Some o f t h e p h y l l i t e s h a v e a f u c h s i t e and  i n these  very close muscovite  the mica has a r e f r a c t i v e  to t h i s proper.  v a l u e ) a n d 2V - 4 9 ° . The g r e e n  green  colour  i n d e x n „ = 1.575 y  (n„ i s z  These p r o p e r t i e s f i t f o r  c o l o u r i s c o n s i d e r e d due t o t h e  Figure  5»  Micaceous q u a r t z i t e cut p e r p e n d i c u l a r to l i n e a t i o n a n d f o l i a t i o n , s h o w i n g weak l a y e r i n g and random o r i e n t a t i o n o f m u s c o v i t e i n q u a r t z . 1 - N i c o l . x 45.  15.  chromium content o f these micas, which was detected i n a q u a l i tative spectrographic analysis. Other p h y l l i t e s have a brownish r e d or maroon c o l o u r . The mica i n these rocks has ny = 1 . 5 7 4  and 2V = 4 5 ;  properties  that f i t w e l l f o r muscovite. Micaceous  quartzite Micaceous  q u a r t z i t e s u n d e r l i e much o f the map a r e a .  An eastward, t r e n d i n g l a y e r of micaceous q u a r t z i t e crops out west o f Haggart Creek f a u l t and continues and swings n o r t h eastward  east of the f a u l t without much apparent change i n  thickness.  Thin layers of p h y l l i t i c  r o c k s , too d i s c o n t i n u o u s  to be mapped, l o c a l l y p l e n t i f u l i n the micaceous q u a r t z i t e s , are d e s c r i b e d elsewhere.  P h y l l i t i c rocks make up l e s s than a  q u a r t e r o f the micaceous q u a r t z i t e map u n i t and are commoner i n the west than i n the e a s t . Many outcrops of the q u a r t z i t e e x h i b i t w e l l jointing.  A good f o l i a t i o n ,  and p h y l l i t i c  developed  due t o very c l o s e l y spaced micaceous  p a r t i n g s , i s n e a r l y u n i v e r s a l and l i n e a t i o n i s gen-  e r a l l y w e l l developed on the micaceous p a r t i n g s .  The q u a r t z i t e  v a r i e s i n c o l o u r from almost white, through l i g h t grey and d u l l g r e e n i s h grey to l i g h t brownish, commonest c o l o u r .  d u l l g r e e n i s h grey b e i n g i t s  Weathered rocks are r e d d i s h brown t o b l a c k .  Micas weather l i g h t golden brown.  16.  • pods,  A v e r y common f e a t u r e  o f the q u a r t z i t e s  and i r r e g u l a r masses o f w h i t e  quartz.  These  erally  l i e i n the f o l i a t i o n  inches  i n d i a m e t e r a n d a f r a c t i o n o f an i n c h  several foot and In  f e e t o r even  o r two.  p l a n e and v a r y  tens o f f e e t  across  the quartz  orientation.  i n thickness,  and t h i c k n e s s e s  to  of a  of minor  folds.  shows a v e r y d e f i n i t e p r e f e r r e d op-  A few f l a k e s  i n the quartz  In  gen-  The q u a r t z m a s s e s a r e commonly i r r e g u l a r l y f o l d e d  thin section  purities  lenses  i n s i z e f r o m a few  a r e e s p e c i a l l y common i n t h e a x i a l p a r t s  tical  are lenses,  o f muscovite  are the only im-  lenses.  thin section  the micaceous  quartzites  a r e seen t o  consist of: 70$ Q u a r t z 25$ M u s c o v i t e  and P e n n i n i t e  5$ A l b i t e The  proportion  Common m i n o r is  of muscovite  constituents  a n uncommon m i n o r  vary  from  defined tion.  Quartz  are u s u a l l y  form  roughly  a r e commonly  across.  equant  .1 mm.  Ellipsoidal  orientation parallel  No o p t i c a l p r e f e r r e d  Quartz g e n e r a l l y  f r o m 4:1 t o 2:1.  a r e s c h o r l i t e and l i m o n i t e .  grains  .04 t o . 3 mm.  preferred  varies  Zircon  constituent.  Quartz g r a i n s ellipsoidal.  to penninite  t o somewhat  across, but  grains  have  t o the main  well linea-  o r i e n t a t i o n i s obvious i n such  shows wavy o r s t r a i n e d  extinction  lamellae  rocks.  17.  (Boehm l a m e l l a e )  t h a t a r e commonly p e r p e n d i c u l a r  B o u n d a r i e s between q u a r t z original  g r a i n s are  g r a i n o u t l i n e s are  Muscovite,  the  sharp  and  other  irregular.  common c o n s t i t u e n t , o c c u r s  i n aggregates of small  generally  i n discontinuous,  Biotite  foliation. No  evident.  t h i n b e n t f l a k e s and segregated  to t h e  i s present  ill  flakes. defined  Micas  in are  bands.  i n s m a l l amounts i n a few  sections  o f macaceous q u a r t z i t e .  Grey  Phyllite Phyllite  and  west  fault.  also in, thin,  quartzite  i n mappable l a y e r s  as much as  crop  rock.  greenish  out  Fresh  micaceous 25$.  i n many p l a c e s , i s s u r f a c e s a r e medium  t i n g e , but weathered  surfaces  d e s c r i b e d p r e v i o u s l y , are  a common  golden.  Lenses of these  Thin  make up  well lineated  occurs  l a y e r s i n the  w h i c h does n o t  a distinctive  are brownish or  feature  i t may  east  t h o u g h i t i s more common  type  discontinuous  rock,  a well foliated, with  This rock  of which  The  grey  i n micaceous q u a r t z i t e both  of Haggart Creek f a u l t ,  west o f the and  occurs  of quartz, rocks.  s e c t i o n s o f the  phyllite  show a f a i r l y  uniform  Figure  7.  Grey p h y l l i t e cut p e r p e n d i c u l a r to foliation and l i n e a t i o n , showing dominant lepidoblastic t e x t u r e and v a r i a t i o n i n g r a i n s i z e . X-Nicols.x  45.  18  mineralogical very  composition which i s given  s i m i l a r to micaceous  higher  proportion  q u a r t z i t e except  Quartz  kOfo  Muscovite  35$  Chlorite  20$  are plagioclase  and z i r c o n .  The g r a i n  Quartz g e n e r a l l y the  foliation.  between q u a r t z detrital  grains  that  The r o c k i s i t contains  grains  (low A n ) ,  limonite,  s i z e i s about  grains  perpendicular  are e l l i p s o i d a l .  a r e i r r e g u l a r and d i s t i n c t .  were s e e n ;  most q u a r t z  and c h l o r i t e  schorlite,  .2 mm.  shows s t r a i n l a m e l l a e  Some q u a r t z  Muscovite  looks  aggregates o f such f l a k e s that  the  foliation.  but  the l a y e r s are p o o r l y  No  original  recrystallized.  are oriented  Segregation of micas i n t o l a y e r s defined  ' b e r l i n blue'  anomalous b i r e f r i n g e n c e  bably  the penninite  variety.  2V=25°, n =1.587 a n d i t i s p r o b a b l y c l o s e y  is fairly  colours  The p r o p e r t i e s  flakes  subparallel to  and d i s c o n t i n u o u s .  shows  fresh  shows a l b i t e  grains.  common  Chlorite and i s p r o -  of muscovite are  to picrophengite i n  composition.  Plagioclase  to  Boundaries  occur i n t h i n , tabular  and  anhedral,  a  of micas.  Minor constituents biotite  below.  twinning and occurs i n  Figure  8.  A n d a l u s i t e h o r n f e l s c u t p e r p e n d i c u l a r to f o l i a t i o n and l i n e a t i o n showing segregation i n t o q u a r t z r i c h and m i c a r i c h l a y e r s . No andalusite i n photograph. X-Nicols. x 15.  19  Andalusite  hornfels  Andalusite diorite  stock  referred  east  h o r n f e l s crops  out around  of Haggart Creek f a u l t .  t o t h e a c c o m p a n y i n g g e o l o g i c map  the quartz  The r e a d e r i s for its distri-  bution.  The and in  the best part  with  rock  does n o t c r o p  specimens occur  destroyed  foliation.  stand  Thin  a purplish tinge  sections  (3 mm.),  grain size  show t h a t  and quartz  layering coincides d u l l , medium t o  surfaces.  i s made up o f a l -  l a y e r s o f about  w h i c h have sharp c o n t a c t s .  o f t h e two t y p e s  MODE($)  GRAIN S I Z E  surface;  p r i s m s up t o a n i n c h  the rock  rich  has been  on t h e f r e s h  Andalusite  equal  The m i n e r a l o g y  o f layers i s given  below.  QUARTZ RICH LAYERS  MICA RICH LAYERS MINERALOGY  Foliation  Relict  i n r e l i e f on w e a t h e r e d  ternating mica r i c h thickness  e v e n on t h e r i d g e s  The r o c k h a s a d i s t i n c t i v e  weathers golden brownish.  in length  and  as f l o a t .  by m e t a m o r p h i s m .  dark grey c o l o u r w i t h it  out w e l l  (mm)  MODE (°/o)  GRAIN S I Z E  Quartz  20  0.1  80  0.2  Biotite  25  0.2  10  0.1  Muscovite  30  0.2  10  0.1  Andalusite  25  2.  —  —  (mm)  F i g u r e 9.  Figure  10  C r o s s - s e c t i o n of e u h e d r a l a n d a l u s i t e c r y s t a l showing the p l e o c h r o i c c o r e . Groundmass c o n s i s t s of q u a r t z and m i c a s . X - N i c o l s . x 1 5 ,  Anhedral a l t e r e d a n d a l u s i t e prism i n a n d a l u s i t e h o r n f e l s . X - H i c o l s . x 15.  20  • I n some t h i n s e c t i o n s corundum, c o r d i e r i t e , plagioclase  and  sillimanite  comprise  U n i v e r s a l minor c o n s t i t u e n t s of the ite  and  contains. greens,  rock are  i n t e r e s t i n g f e a t u r e o f the  In the  while  quartz  o f the  rock.  schorlite,  of the mica r i c h  i s pleochroism  l a y e r s has  in  a pleo-  scheme i n b r o w n s .  of the muscovite  27=30°, n = 1 . 5 7 7 , y  i s near  the p i c r o p h e n g i t e  series.  I n some t h i n  sections andalusite i s i n euhedral,  v e r y f r e s h , u n a l t e r e d g r a i n s which have p l e o c h r o i c c o r e s show t h e  a-b  = Z-Y  - p i n k i s h orange - very f a i n t  yellow  green  I n o t h e r t h i n s e c t i o n s the a n d a l u s i t e a r e pleochroism;  i n these  i t is full  lend i t a p o i k i l o b l a s t i c The warrants  that  f o l l o w i n g scheme. c = X  occurrence  green  of f l a k e s  and  of muscovite  o f corundum i n some o f t h e s e  blues.  i n the r o c k and  subhedral  show no that  texture.  s p e c i a l mention.  i n p u r p l e and layers  limon-  r o c k i s the b i o t i t e i t  rich layers biotite  the b i o t i t e  Muscovite, end  t o 20$  zircon.  An  ehroie  up  chlorite,  The  m i n e r a l has  It i s largely  i s more p l e n t i f u l  strong  rocks  pleochroism  restricted  to the micaceous  i n r o c k s c l o s e to the  gran-  Figure  11.  A n h e d r a l g r a i n s o f corundum ( h i g h r e l i e f ) i n a groundmass o f m i c a s and q u a r t z . 1-Nicol. x  45.  21  itic  contact.  The m i n e r a l occurs as s m a l l f r a c t u r e d ,  equant g r a i n s and i n aggregates  anhedral,  of such g r a i n s that are  gener-  a l l y e n c l o s e d i n muscovite. Quartz  i n these rocks occurs as f r e s h , equant g r a i n s  w i t h i r r e g u l a r , sharp boundaries  and uniform e x t i n c t i o n .  No  s t r o n g p r e f e r r e d o p t i c a l o r i e n t a t i o n i s e v i d e n t upon c a s u a l examination. The  o v e r a l l t e x t u r e of these rocks i s t y p i c a l l y  granoblastic. Interbedded w i t h a n d a l u s i t e h o r n f e l s are  phyllitic  q u a r t z i t e s which c o n t a i n a l a r g e r p r o p o r t i o n of quartz the a n d a l u s i t e h o r n f e l s , but which are otherwise The  rock i s made up of quartz l a y e r s about 5 mm.  are separated by p h y l l i t i c  than  identical. t h i c k which  p a r t i n g s l e s s than . 2 mm *;- t h i c k .  Near the g r a n o d i o r i t e c o n t a c t the p h y l l i t i c  1  partings contain  andalusite. Quartz  diopside hornfels T h i s d i a g n o s t i c rock occurs i n the south e a s t e r n  corner of the map zite,  area.  Andalusite hornfels, p h y l l i t i c  quart-  skarn and marble are i n t e r b e d d e d with i t . Outcrops  of quartz d i o p s i d e h o r n f e l s form the steep  b l u f f s of Ray Gulch and other creeks t h a t f l o w southward i n t o  Figure  12.  B l u f f s west o f Ray G u l c h p r o v i d e good e x p o s u r e s of a n d a l u s i t e h o r n f e l s , quartz d i o p s i d e h o r n f e l s and i n t e r b e d d e d m i c a c e o u s q u a r t z i t e . Outcrop i s p o o r e r t h a n t h i s i n a l l o t h e r p a r t s o f the map area.  22  Lynx Creek. layering. white  The r o c k i s w e l l Alternating  (quartz In  the  rich)  layers  are green  and are about  thin sections  5  (diopside  '  r i c h ) and  thick.  mm  i t i s c l e a r that  M0DE($)  the l a y e r i n g o f  10  .3  Diopside  65  .5  Calcite  W HITE BANDS GRAIN SIZE(mm.)  GREEN BANDS GRAIN SIZE(mm.)  Quartz  M0DE($) '  50  .1 ,  15  .2  10  5  Biotite  10  5  10  Actinolite  5 .2  5  Minor constituents  10 present  .2  i n most s e c t i o n s  z i r c o n , corundum, o p a q u e s , s c h o r l i t e a n d sphene.  sections layers,  the minor c o n s t i t u e n t s while  i n others  In most s e c t i o n s clase  small  and m u s c o v i t e  a r e more p l e n t i f u l  they a r e c o n f i n e d  are also  present.  largely  to green  Overall between l a y e r s  texture  Grain  most o f t h e m i n e r a l s grains.  i n the green layers.  chlorite, plagio-  One s e c t i o n  contains  which i s confined  layers.  are sharp.  granoblastic.  examined I n some  t o the white  amounts o f e p i d o t e ,  about t w e n t y - f i v e p e r c e n t c l i n o z o i s i t e ,  is  defined  rock i s a r e f l e c t i o n of i t s composition.  MINERALS  are  j o i n t e d and h a s a w e l l  of the rocks I s layered, Within individual layers  size  o f these  the c o n t a c t s the texture  r o c k s i s somewhat v a r i a b l e ;  occur i n equant, s u b h e d r a l  A tendency f o r the green l a y e r s  to anhedral  t o be o f somewhat  Figure  13.  D i o p s i d e i n q u a r t z : the t y p i c a l a s s o c i a t i o n i n g r e e n bands o f q u a r t z d i o p s i d e h o r n f e l s . 1-I'Iicol. x 15.  Figure  Ik.  Quartz d i o p s i d e h o r n f e l s . M i n e r a l s are c a l c i t e ( c ) d i o p s i d e ( d ) q u a r t z ( q ) and a c t i n i l i t e ( a ) . Note the r o u g h l a y e r i n g . 1 - N i c o I . x 15.  23  coarser grain  size  The  eral  the white  clinopyroxene  some d e t a i l . was n o t e d .  than  layers  i s fairly  i n t h e r o c k h a s "been s t u d i e d i n  I t s c o l o u r i s pale green  and no p l e o c h r o i s m  I n c r o s s s e c t i o n s p e r p e n d i c u l a r t o 'c' the min-  shows w e l l d e f i n e d p a r t i n g  diallage.  The m i n e r a l  on (100) c h a r a c t e r i s t i c o f  i s biaxial  + v e : 2V o f f i v e  e a c h s e c t i o n was m e a s u r e d a n d a v e r a g e d . for  the f i v e  degrees.  s e c t i o n s measured  In individual  tion  o f 2V o f a b o u t  less  than  The  exists  pyroxene D±S8  is  index  =  W050  56,  angles  55 and 53 showed a v a r i a -  o f the average  (somewhat  specimens).  around  .029.  -  Only  slight  variation  .004 was o b t a i n e d .  Bire-  These p r o p e r t i e s d e f i n e t h e  variable  i n composition  E n ^ Fe£ a n d W 04/^1. En^o, E e ^ i .  between  The p y r o x e n e  therefore diopside.  Quartz sharp  boundaries.  b u t weak l a m e l l a r in  o f 1.681  as b e i n g l i n e a r l y  Hed]_2  57»  o f 2V between d i f f e r e n t  i n w h i c h 2V was m e a s u r e d .  averages  The r e s u l t i n g  s e c t i o n s the pyroxene side  grains i n  n-y f o r t h e p y r o x e n e was a l s o m e a s u r e d f o r  a n d an a v e r a g e  fringence  a r e 58)  2° on e i t h e r  the v a r i a t i o n  refractive  each rock  general.  every  i n equant,  The m i n e r a l extinction  small grains with  irregular,  g e n e r a l l y shows u n i f o r m  i s present  i n at least  extinction,  some g r a i n s  section.  Calcite stitial  occurs  occurs  i n large,  g r a i n s t h a t show e x c e l l e n t  irregular, lamellar  anhedra,  twinning.  inter-  24.  A second of hornblende,  type  z c 16°,  some s e c t i o n s .  The  of amphibole w i t h h i g h -ve  2V  occurs  mineral i s closely  xene, which appears  pleochroism  typical  infrequently  associated with  in pyro-  t o have grown a t the e x p e n s e o f t h e  amph-  ibole.  A green,  medium g r a i n e d , m a s s i v e  skarn occurs l o c a l l y  w i t h i n the  Masses of skarn are conformable contacts  are  sharp.  to t h a t o f the green its  grain  size  a hornfelsic  The  with  of quartz  i s c o a r s e r than  diopside  quartz diopside h o r n f e l s .  composition  layers  quartz  the  surrounding  of t h i s  rocks  skarn i s  and  similar  d i o p s i d e h o r n f e l s , but  i n the h o r n f e l s .  The  skarn  has  texture.  INTRUSIVE ROCKS Biotite  Quartz  Diorite  Petrology  The  stock east of Haggart Creek f a u l t  west o f i t a r e composed lated  lithologic  of these  bodies  rocks vary sition ally  of b i o t i t e  types.  The  i n composition  and  of t h e i r p l a g i o c l a s e  found  in relatively  'sill*  other re-  l o c a t i o n and  site  a c c o m p a n y i n g g e o l o g i c map.  t h e i r c o l o u r i n d e x and  do n o t  acid  the  g r a n o d i o r i t e and  distribution,  i s shown i n t h e  and  correspond with  rocks.  The  the  compo-  those  gener-  ab twin  Figure  16.  P o r p h y r i t i c b i o t i t e quartz inonzonite phenocrysts of p l a g i o c l a s e , q u a r t z and b i o t i t e i n a groundmass o f q u a r t z and f e l d s p a r . Some p l a g i o c l a s e p h e n o c r y s t s are zoned. X-Nicols. x 15»  25.  In outcrops  general  the g r a n i t i c  a r e d e e p l y w e a t h e r e d and c r u m b l y .  a l l y w e l l developed.  The f r e s h  phases a r e dark grey; are weathered of  rocks crop  fresh  surfaces.  darker  grey,  a r e more u n i f o r m  The r o c k  those  e a s t o f the f a u l t  speaking  and  the g r a n i t i c  i n composition  rocks  east o f the f a u l t  and more a c i d i c  in  quartz  and p l a g i o c l a s e : ;  to  quartz  diorite.  andesine,  East  these  rocks  those  diorite.  approach quartz  of Haggart Creek f a u l t  w h i l e west o f t h e f a u l t  west  West  plagioclase  tends  to vary  mineral i s b i o t i t e  from  An^  from  2  "to A n ^ .  are presented  below.  was  The noted.  f r o m east o f t h e  a porphyritic  t o a medium g r a i n e d g r a n o d i o r i t e .  i n compo-  i n rocks o c c u r r i n g  t h o u g h some h o r n b l e n d e  show t h a t t h e r o c k v a r i e s  two t y p e s  plagioclase i s  regularly  The f e l d s p a r i s more a n d more c a l c i c f u r t h e r west a n d r a n g e s  gabbro  i t i s labraborite.  Thin s e c t i o n s o f the quartz d i o r i t e  these  than  t h e r o c k s g e n e r a l l y l a c k K - f e l d s p a r and a r e r i c h  West o f t h e f a u l t  zonite  often  chlorite.  the f a u l t  fault  grains  and they  of  varietal  than  c a n be d i s t i n g u i s h e d i n  i t and approach q u a r t z m o n z o n i t e and q u a r t z  successively  b u t some  i s medium g r a i n e d ;  of  sition.  i s gener-  surfaces are darker coloured  a larger proportion of b i o t i t e  ' Broadly  calcic  Most  The r o c k s w e s t o f H a g g a r t C r e e k a r e g e n e r a l l y  i n c o l o u r than  contain  Jointing  rock i s l i g h t  q u a r t z , p l a g i o c l a s e and b i o t i t e  handspecimens.  out w e l l .  q u a r t z mon-  E s t i m a t e d modes f o r  F i g u r e 17.  Medium g r a i n e d b i o t i t e g r a n o d i o r i t e . Shows both zoned and unzoned p l a g i o c l a s e g r a i n s X-Nicols. x 15.  26.  MINERALS  Medium G r a i n e d biotite granodiorite  Porphyritic Biotite Quartz Monzonite  Quartz  30$  30$  Plagioclase  15$  30$  K-feldspar  40$  20$  Biotite  7$  Hornblende  Minor c o n s t i t u e n t s of these opaques, a p a t i t e ,  sphene, m u s c o v i t e ,  Secondary m i n e r a l s are p r e s e n t  are c a l c i t e ,  i n amounts up  The  porphyritic  w h i c h r a n g e i n s i z e up to a t h i r d  of i t .  to  rocks include zoisite  chlorite  and  and  zircon,  schorlite.  sericite  which  15$»  r o c k i s made up  t o 3 mm«  o f equant  phenocrysts,  a c r o s s and w h i c h c o n s t i t u t e  G r a i n s i n t h e groundmass a r e commonly  up  .1  mm.  across.  Phenocrysts fairly  of quartz  regular boundaries.  irregular  a r e e q u a n t , u n s t r a i n e d and  Quartz  have  g r a i n s i n t h e groundmass have  boundaries.  Plagioclase Most phenocrysts  phenocrysts  show o s c i l l a t o r y  are  subhedral  zoning  and  no  and  thick tabular.  definite  trand  t o e i t h e r n o r m a l o r r e v e r s e z o n i n g c o u l d be  established.  Zoned  p l a g i o c l a s e g r a i n s a r e more e q u a n t t h a n a r e  unzoned g r a i n s .  Most zoned g r a i n s have s i x narrow o u t e r zones around a l a r g e uniform  core.  Zoned g r a i n s have  smooth r o u n d e d  boundaries,  F i g u r e 18.  P a r t l y a l t e r e d p o r p h y r i t i c gabbroic b i o t i t e quartz d i o r i t e from west of Haggart Creek. X - H i c o l s . x 15.  F i g u r e 19.  P a r t l y a l t e r e d gabbroic b i o t i t e quartz d i o r i t e from west o f Haggart Creek showing quartz pheno< c r y s t s with smooth resorbed boundaries s u r r ounded by c l a y aggregates. X-I\ icols. x 1 5 . T  27.  whereas t h e b o u n d a r i e s  o f unzoned g r a i n s a r e g e n e r a l l y s t r a i g h t .  B o t h t h e u n z o n e d a n d z o n e d g r a i n s a r e o f t h e same and  average  carlsbad in  a r o u n d An^Q.  and p e r i c l i n e  twins  from  f e l d s p a r occurs  t h e groundmass.  plagioclase  along  Large  the ubiquitous a l b i t e  are f a i r l y  t h e groundmass o c c u r s i n a n h e d r a l  Potash in  Aside  composition  common.  The p l a g i o c l a s e  g r a i n s about  as a n h e d r a l ,  (001), while myrmekitic  .1 mm.  across.  interstitial  g r a i n s show p e r t h i t i c  twins,  grains  intergrowths of  and g r a n o p h y r i c  inter-  g r o w t h s o f q u a r t z a n d K - f e l d s p a r a r e common i n s m a l l e r g r a i n s . Carlsbad  twinning  i s common i n l a r g e r g r a i n s .  Biotite, tabular euhedral  the main v a r i e t a l m i n e r a l , occurs i n t h i n  g r a i n s up t o 2 mm.  across.  The m i n e r a l h a s  t h e p l e o c h r o i c scheme:X = e - pale yellow Y=Z = a = b Hornblende matic  grains with  i n greens  dark  occurs  ragged  green  r e d brown  i n r o u g h l y equant and s h o r t  terminations.  and. shows s i e v e t e x t u r e .  pris-  The m i n e r a l i s p l e o c h r o i c  Biotite  i s closely associated  wi t h i t .  Sericitization clase  grains.  i s e v i d e n t i n t h e c o r e s o f some p l a g i o -  Some b i o t i t e  g r a i n s are completely  penninite,  b u t i n most g r a i n s r e p l a c e m e n t  controlled  by t h e c l e a v a g e  of b i o t i t e .  r e p l a c e d by  i s only p a r t i a l  and i s  E p i d o t e h a s f o r m e d as  28.  an  alteration  The idiomorphie  of  hornblende.  medium g r a i n e d g r a n o d i o r i t e i s a t y p i c a l l y h y p -  rock.  Grain size  Plagioclase  i n these r o c k s  than i t i s i n the p o r p h y r i t i c The  mineral  2 mm. and  occurs  across.  i n these  porphyritic  About  i s somewhat more  one t h i r d  thick  about  calcic An^.  t a b u l a r g r a i n s about  of plagioclase  g r a i n s a r e zoned  the zoning i s s i m i l a r t o t h a t d e s c r i b e d f o r the rock.  Potash  Twinning  i n the p l a g i o c l a s e  i s t h e same a s  rock.  f e l d s p a r occurs  i n anhedral  t h a t show c a r l s b a d t w i n n i n g  perthitic  mm.  r o c k s and averages  i n subhedral,  that i n the p o r p h y r i t i c  grains  i s about 2  and s u b h e d r a l  and w h i c h o f t e n c o n t a i n  lamellae.  Quartz  g r a i n s have i r r e g u l a r b o u n d a r i e s  and wavy  extinction.  Biotite a r e more p l e n t i f u l are  i s the v a r i e t a l  Alteration common a n d i s s i m i l a r  Creek f a u l t .  Minor constituents  and c o a r s e r g r a i n e d i n t h i s  i n the p o r p h y r i t i c  At l e a s t  mineral.  rock  than  they  variety.  by c h l o r i t e ,  sericite  and c a r b o n a t e i s  to that d e s c r i b e d before.  two o t h e r p h a s e s e x i s t  One, w h i c h a p p e a r s  east of Haggart  restricted  t o t h e w e s t end  29  of the s t o c k ,  i s a fine  mafic minerals The  extent  grained, a p l i t i c  a n d made up e n t i r e l y  of this  as much a s one t h i r d  rich  altered,  granitic  average  Biotite  (Phenocrysts  (Phenocrysts)  (Groundmass) (Groundmass) Hornblende  entirely  i n locale i s  p h a s e i n w h i c h b i o t i t e makes up The c o n t a c t s a r e t h o u g h t  to  o f t h e phase i s u n c e r t a i n .  medium  T h e i r q u a r t z and f e l d s p a r c o n t e n t  (Phenocrysts)  K-feldspar  zircon  t o be g r a d a t i o n a l .  greenish to white,  (Phenocrysts)  K-feldspar  between  grained i s variable.  mode i s g i v e n b e l o w .  Plagioclase  Quartz  The c o n t a c t  r o c k s west o f Haggart Creek f a u l t a r e  allotriomorphic,  andpporphyritic.  Quartz  and f e l d s p a r .  i s thought  o f the rock.  g r a d a t i o n a l and t h e e x t e n t  The  An  of quartz  type which i s a p p a r e n t l y n o t r e s t r i c t e d  a medium g r a i n e d , b i o t i t e  be  c o n t a i n i n g no  phase i s n o t c e r t a i n .  t h i s p h a s e and t h e n o r m a l t y p e s Another  type  absent.  and i r o n  occurs  15 - 2 5 $ 0 -  20$  0 -  2$  10 -  20$  5 -  55$  0 -  20$  i n some s p e c i m e n s , b u t i s u s u a l l y  M i n o r c o n s t i t u e n t s i n c l u d e sphene, sulphides.  Schorlite  apatite,  o c c u r s uncommonly a s a  minor c o n s t i t u e n t .  Secondary m i n e r a l s amounts o f t h e s e  include calcite  and c h l o r i t e .  two m i n e r a l s v a r y c o n s i d e r a b l y .  The  Figure  20.  Strongly altered gabbroic biotite quartz d i o r i t e from west of Haggart Creek fault X-Hicols. x 15.  30  One m i n o r c o n s t i t u e n t w h i c h was n o t n o t e d i n any sections vidual,  i s allanite. prismatic  gives  Plagioclase  i n these  grains  commonly h a v e  that  a r e a b o u t 2 mm.  there  to  Ans£»  i s a suggestion  rocks  that  successively  described  generally  so c o m p l e t e  and  grains  only  i s commonly  a large  zones.  twinning.  smooth  core i s  Plagioclase  Plagioclase i s  and t h i s  alteration i s grains  are obscured.  orthoclase)  similar  i s i n large,  to those of p l a g i o c l a s e  twinning.  Quartz o c c u r s i n equant, rounded g r a i n s usually with  calcic  outlines of plagioclase  (probably  of dimensions  shows c a r l s b a d  examined  i s o s c i l l a t o r y and  Usually  and c a l c i t e  and even t w i n l a m e l l a e  Potash f e l d s p a r anhedral  The z o n i n g  and p e r i c l i n e  a l t e r e d to s e r i c i t e  evident  boundaries  sections  Plagioclase  previously.  partially  are  tabular,  I t s composition  t o n i n e narrow o u t e r  that  allanite  p l a g i o c l a s e i s more and more  similar  carlsbad  The  smooth, r o u n d e d  Prom t h e few t h i n  i s not u n i v e r s a l .  shows a l b i t e ,  recognized  o c c u r s as t h i c k ,  f u r t h e r west.  s u r r o u n d e d by f r o m f i v e  Gulch.  dimension.  zoned, but t h i s to that  c a n be  indi-  and thus i s n o t m e t a m i c t .  rocks  i n longest  that  thin,  f i g u r e s prominently i n the  a good X - r a y powder p a t t e r n ,  ranges from A n ^  in  This mineral  sands o f H a g g a r t Creek and D u b l i n  subhedral and  occurs i n black,  up t o 2 cm. l o n g  grains  i n handspecimens. placer  This mineral  thin  'resorbed'  boundaries,  2 - 3 mm.  across  around which v e r y  fine  31  grained  aggregates  m i n e r a l has  of c l a y m i n e r a l s are  uniform  zones o f t i n y  extinction  equant  Biotite  sometimes shows c o n c e n t r i c  thick,  terminations.  t a b u l a r g r a i n s which The m i n e r a l  c o m p l e t e pseudomorphous r e p l a c e m e n t  The to  a fine  and  clays.  fresh  the  i s certainly  mafic  c o n s t i t u e n t s f o r gabbros  The  and  flicting name l i k e dioritic  nor  but  ( i . e . p y r o x e n e s ) and i s more t y p i c a l  f e a t u r e s make i t n e c e s s a r y or c a l c i c  biotite  quartz bearing b i o t i t e  names i s p r e f e r r e d .  mm.  that  to g i v e  Plagio-  The  the  presence  of d i o r i t i c  rock.  These  rocks.  con-  the rock a h y b r i d  quartz d i o r i t e  gabbro.  the  the l a c k o f normal  i s too h i g h f o r a d i o r i t i c  gabbroic  .05  than  a quartz gabbro.  of gabbros,  some h o r n b l e n d e  c o l o u r index  of quartz, K-feldspar  foregoing description i t i s clear  clase  biotite  or  i s generally altered  of mixtures  rock i s n e i t h e r a quartz d i o r i t e  of  shows p a r t i a l  chlorite.  i s generally less  typical  gen-  o f c l a y m i n e r a l s , b u t where i t i s  i t consists  Grain size  From  by  groundmass o f t h e s e r o c k s  g r a i n e d aggregate  relatively  The  inclusions.  o c c u r s as  e r a l l y have ragged  and  randomly arranged.  first  or  even  of these  two  Figure 21.  W i n d l a s s above o l d s h a f t sunk on the n o r t h e r n c o n t a c t o f the g r a n o d i o r i t e s t o c k of D u b l i n Gulch (here m i n e r a l i z e d by a u r i f e r o u s a r s e n o p y r i t e ) . Note the d i s t i n c t f o l i a t i o n i n the g r a n o d i o r i t e o u t c r o p , which i s thought to be due to s h e a r i n g upon i n t r u s i o n a l o n g the f a u l t a t the c o n t a c t w i t h the metamorphic r o c k s .  32  Structure  Stratum give a c l e a r Figure  i d e a o f the  The  stratum  The  stock'has  A r e a s where the  and  south  contacts  twenty-five  thins  and  intrusion  i s more  metamorphic granitic  stock  are  in relation  rocks  o f the  stock To  somewhat d i v e r g e n t ,  stock.  is fairly t h e west,  conform w i t h  the  on  are u n d e r l a i n  The  d i p of the  uniform the  and  stock  by  north  averages  gradually  stock,  foliations  the northwestward dip of  the  the  southeast  in  the  the  side f o l i a t i o n s  are  not  contact..  the  country  conforms w i t h  Occasionally distinct  Close  Gulch.  sill-like.  contact with  to s h e a r i n g  'ridges'.  West o f H a g g a r t C r e e k f a u l t  n o r t h w e s t m a r g i n o f the  e x p o s e d and  top-  a l s o shown.  surface i s high,  degrees.  contact, while  The  to the  ridges coincides with Dublin  of the  stock  granodiorite stock.  t h e n o r t h w e s t s i d e o f the  conformable with  a fault  upper s u r f a c e o f the  o f the  main,  becomes dyke l i k e .  On  due  two  i n the u p p e r s u r f a c e  rocks.  the  contours  topographic  about  well  form  v a l l e y between t h e s e  highs  on  shows t h e makeup o f t h e  ography.  The  contours  rocks.  i s considered  The  fault  to  be  is locally  t h e f o l i a t i o n o f the m e t a m o r p h i c layering  i n them, o c c u r s  t o and  stock  i n the  parallel  granitic  t o and  rocks,  n e a r the  west of H a g g a r t Creek f a u l t ,  fault.  foliations  33  south o f the g r a n i t i c of  the s t o c k , but  rocks are  f u r t h e r west,  Prom t h e s t r a t u m quartz that to  diorite  the  that  the  s t o c k f o r m s t h e backbone o f P o t a t o H i l l s  and  shoots  from  Origin  and mode o f  of  apophyses o r  of both  rocks i n t h i s  epi-and mesozonal  area exhibit types  off-  features char-  (Buddington  granophyric  structure  t e x t u r e , the  due  to t h e p r e s e n c e  tourmaline  1959).  o f c o u n t r y r o c k i n the  are the q u a r t z d i o r i t i c  t e x t u r e and margins,  lack  t h e low  r o c k s and  of m i a r i o l i t i c  s t o c k and,  grade  the p r e s e n c e  It  fault.  possibly,  stock. the  lack the  Mesozonal  hypidiomorphic  the l a c k of  r e g i o n a l metamorphic n a t u r e  of  chilled country  of p e r i p h e r a l h o r n f e l s e s .  seems l i k e l y  s t o p i n g and  composition, cavities,  of various  a u r e o l e , the  c o n t a c t a l o n g p a r t of the m a r g i n of the  bedding  diorite  f e a t u r e s o f t h e s t o c k i n c l u d e t h e homophanous t e x t u r e  features  by  masses of q u a r t z  emplacement  granitic  inclusions  fault  sill-like  o f the s t o c k a p p e a r t o be  stock, composite  phases,  i n shape  t h e m a i n mass.  The  Epizonal  i s similar  stock.  the margins  acteristic  conformable.  i t i s apparent  topography west of P o t a t o H i l l s o f the  orientation  that  around  the  t h e y become more  contours  Several l e n t i c u l a r  of  t r a n s v e r s e to the  intrusion  that  the g r a n i t i c  t h a t was  initially  I t i s considered that  r o c k s were  emplaced  controlled  by  the presence  o f two  a types  Figure  22»  S t r a t u m c o n t o u r s on t h e u p p e r s u r f a c e o f g r a n o d i o r i t e stock east o f Haggart Creek w i t h 3 accompanying c r o s s s e c t i o n s .  STRATUM CONTOURS ON THE UPPER SURFACE OF GRANODIORITE STOCK EAST OF HAGGART CREEK WITH THREE ACCOMPANYING CROSS-SECTIONS  34.  of  p l a g i o c l a s e i n the rock comprising  as  a clue  of  the stock.  before ssure  t o and i n support  t h e u n z o n e d f e l d s p a r and r e f l e c t s  stallized occurred  after  proportions  emplacement  The in  the s i l l  of  their  o f t h e two t y p e s  stage.  cry-  l i q u i d magma  of plagioclase give and s o l i d  during  A t t h e t i m e o f emplacement t h e c r y s t a l 25$ solid.  similarity  o f zoned c r y s t a l s  i n the s t o c k  i s thought  t o those  t o be  evidence  common o r i g i n .  p r o g r e s s i v e change o f p l a g i o c l a s e  the length  o f the s i l l  west  t h e m o t i o n o f magma d u r i n g  accordance with  Quartz F e l d s p a r  compositions  o f Haggart Creek f a u l t  emplacement was f r o m west  t h e p l a g i o c l a s e phase  suggests to east  diagram.  Porphyry  Several area.  t o have  ceased.  amounts o f l i q u i d  west o f H a g g a r t C r e e k f a u l t  The  the  partially  t h e movement o f emplacement  mush was a p p r o x i m a t e l y  in  t h e changes i n p r e -  Unzoned f e l d s p a r i s t h o u g h t  a rough i d e a o f the r e l a t i v e  that  formed  conditions that p r e v a i l e d during the  when c o o l i n g o f t h e s t i l l  The  along  t o have  origin  o f movement o f t h e magma f r o m i t s b i r t h p l a c e t o i t s new  home i n t h e z o n i n g .  the  o f t h e e s s e n t i a l l y magmatic  The z o n e d f e l d s p a r i s c o n s i d e r e d  and temperature  period  t h e s t o c k may be u s e d  dykes o f . q u a r t z  Their location  f e l d s p a r porphyry crop  and d i s t r i b u t i o n  out i n  i s shown on t h e a c c -  35.  ompanying g e o l o g i c map.  The  d y k e s a r e made up o f a w h i t i s h f i n e , g r a i n e d  groundmass i n w h i c h e q u a n t p h e n o c r y s t s ionally  f e l d s p a r a r e randomly d i s t r i b u t e d .  strongly  altered,  i t s original  have a l l been c o m p l e t e l y is  o f q u a r t z and o c c a s -  indistinguishable  from  The r o c k i s  c o n s t i t u e n t s , except  converted  to micas,  quartz,  so t h a t t h e r o c k  the a l t e r e d basic quartz d i o r i t e i n  thin sections.  Porphyritic  amygdaloidal  Float  basalt  of porphyritic  west o f H a g g a r t C r e e k f a u l t . thought since  that the f l o a t  the area  phyritic  basalt  overlies  Por-  i n the v i c i n i t y o f  (Green  i s dark  grey  1962) p o r p h y r i t i c  o r black i n c o l o u r , weathers  I t i s made up o f a f i n e  e q u i g r a n u l a r groundmass o f b y t o w n i t e , ( 3 mm.)  are randomly d i s t r i b u t e d . thin  i s small.  t o be o f T e r t i a r y a g e .  r u s t y brown a n d i s m a s s i v e .  which phenocrysts  It is  a v o l c a n i c f e e d e r dyke o r n e c k ,  Prom r e g i o n a l m a p p i n g  float  a t two l o c a l i t i e s  ( S e e a c c o m p a n y i n g map)  occurs a t other l o c a l i t i e s  i s considered The  occurs  over which i t i s d i s t r i b u t e d  basalt  t h e map a r e a .  basalt  a u g i t e and b i o t i t e i n  of plagioclase, The a v e r a g e  s e c t i o n s o f specimens from  both  grained  p y r o x e n e and q u a r t z  e s t i m a t e d mode f o u n d i n  localities  i s g i v e n below.  Figure 23.  P o r p h y r i t i c amygdaloidal b a s a l t . Phenocryst of bytownite with smooth boundary and r e a c t i o n rim i n a groundmass o f randomly o r i e n t e d t h i n tabular plagioclase grains. The round g r a i n , lower l e f t , i s an amygdule o f c a l c i t e . X-Nicols, x 15.  F i g u r e 24.  Large phenocrysts made up of i n d i v i d u a l rounded g r a i n s of sanidine and c u t by 'worms' of p l a g i o c l a s e and quartz i n p o r p h y r i t i c amygdaloidal basalt. X-Mcols. x 15.  36. Augite  (Groundmass)  Augite  (Phenocrysts)  20$ 5$  Bytownite  (Phenocrysts)  10$  Bytownite  (Groundmass  30$  Quartz  Sanidine, in  Biotite  10$  Calcite  10$  olivine,  one t h i n  5$  sphene a n d p y r i t e  s e c t i o n i n d e c r e a s i n g o r d e r o f abundance.  The groundmass tabular, albite  euhedral  c o n t a i n s randomly o r i e n t e d ,  grains of plagioclase  interstitial  (W039  ( A n y o ) t h a t show  50° and i s b i a x i a l  n  = 1.675. Biotite  groundmass.  Fe£) occurs  The m i n e r a l h a s a 27  + v e , i t s b i r e f r i n g e n c e i s .026 and  occurs  as t i n y  interstitial  f l a k e s i n the  The m i n e r a l i s p l e o c h r o i c i n browns.  Z:oned p h e n o c r y s t s and more t h a n 3 mm. rounded boundaries composition  as a n h e d r a l , e q u a n t ,  g r a i n s i n the groundmass.  of  of bytownite  a r e a n h e d r a l , equant  a c r o s s . ' They have r e s o r b e d , s m o o t h l y and show c a r l s b a d and a l b i t e  i s c l o s e t o t h e groundmass  Augite grains  thin  twinning.  Augite  y  are c o n s t i t u e n t s found  phenocrysts  twinning.  Their  plagioclase.  o c c u r as s u b h e d r a l ,  r o u g h l y equant  t h a t show a n a r r o w o u t e r zone s u r r o u n d i n g a l a r g e r  inner  Figure  2 5.  Grain of L i o p s i t i c Augite i n A u g i t i t e showing c l e a v a g e ( 1 1 0 ) and p a r t i n g ( 1 0 0 ) as w e l l as t w i n n i n g on ( 1 0 0 ) . X-Nicols. x 45~  Figure  26.  L a r g e g r a i n s o f h o r n b l e n d e rimmed by s m a l l grains of a c t i n o l i t e (acicular habit) m' Augitite. Other m i n e r a l s are biotite~ a l b i t e and pyroxene. 1 Nicol. x 45.  37.  core.  The  o u t e r zone has  a lower  refractive  index than  the  core.  Quartz smooth r e s o r b e d  o c c u r s as u n s t r a i n e d , e q u a n t p h e n o c r y s t s boundaries.  A large up  (1 cm.)  equant phenocryst  o f a number o f i n d i v i d u a l ,  t h a t m i n e r a l and or  quartz, that  thin  with  c u t by  differently  o f s a n i d i n e made  oriented grains of  t i n y wormlike v e i n l e t s  transgress g r a i n boundaries,  of  plagioclase  occurs i n  one  section.  Anhedral section.  phenocrysts  The m i n e r a l i s a l t e r e d  Rounded k n o t s calcite  of o l i v i n e  crystals  to s e r p e n t i n e along  o c c u r i n the b a s a l t .  t o 5 nun.  Alteration  occur i n  filling.  I t i s considered  The  c a l c i t e knots  this  fractures.  of y e l l o w i s h prismatic r a d i a l l y  this mineral i s a vesicle d u l e s a r e up  also  arranged that  o r amyg-  across.  of t h i s  rock  t y p e i s weak.  Augitite  Two  s m a l l , d y k e - l i k e masses o f dark  coarse-grained crops  are  augitite  o c c u r west o f Haggart  covered w i t h dark  green  residual  c o u n t r y r o c k s a r e nowhere e x p o s e d , b u t the f o l i a t i o n The  augitite  i s unfoliated  and  fine  Creek f a u l t .  soil.  Contacts  to Outwith  t h e masses t r e n d a c r o s s  o f the micaceous q u a r t z i t e s itself  green,  that  lacks  surround  layering.  them.  38  The subhedral grains ing it. mm.  r o c k i s made up o f an a g g r e g a t e  equant c r y s t a l s  o f amphibole  of euhedral to  o f p y r o x e n e and s h o r t p r i s m a t i c  i n varying proportions.  Biotite  amounts i s i n c l u d e d i n p y r o x e n e a n d o c c u r s Albite  occurs  and 5 mm.,  interstitially.  but i s uniform  i n individual  Modes a r e q u i t e v a r i a b l e w i t h i n a few f e e t alogical  Grain size  Diopside  i n t e r s t i t i a l to ranges  specimens.  50 -  from  different  Two e x t r e m e s a r e p r e s e n t e d augite  b e t w e e n .2  f o r even specimens  o f each o t h e r have w i d e l y  constitution.  i n vary-  miner-  below.  7$  Hornblende  5 -  51$  Biotite  5 - 20$  Albite  15 - 10$  K-feldspar  15 -  0$  Olivine  0 - 1 $  Epidote  2$  M i n o r c o n s t i t u e n t s i n c l u d e , i n d e c r e a s i n g o r d e r o f abundance, apatite,  sphene a n d m a g n e t i t e .  chlorite  and a c t i n o l i t e . Clinopyroxene  surrounded  occurs  Secondary m i n e r a l s  as s u b h e d r a l  are c a l c i t e ,  grains generally  by a m p h i b o l e a n d o f t e n s h o w i n g p o i k i l i t i c  The m i n e r a l h a s a 2V o f 5 2 ° , i s b i a x i a l  due  to included b i o t i t e .  +ve  a n d i s p l e o c h r o i c i n v e r y weak b l u e g r e e n  scheme was n o t d e t e r m i n e d .  texture  Twinning  and p i n k ;  the  on ( 1 0 0 ) i s common.  m i n e r a l h a s a b i r e f r i n g e n c e o f .027 a n d a r e f r a c t i v e  The  index  F i g u r e 27.  "Checkerboard" t w i n n i n g i n i n t e r s t i t i a l from a u g i t i t e . x 45.  albite  n  y  = 1.675.  The c o m p o s i t i o n i s n e a r  WO^Q  E n ^ Fe^ (diopside  augite). Two a m p h i b o l e s o c c u r . grained,  crystals  are subhedral  w i t h 2V=75°, shows t w i n n i n g  The commonest type and bent.  i s coarse  I t i s b i a x i a l -ve  on (100) and i s p l e o c h r o i c a s  follows: X a - pale  green  Y b - very l i g h t  green  Z c - moderate b l u e  green.  These p r o p e r t i e s a r e c h a r a c t e r i s t i c  o f common h o r n b l e n d e .  coarse  g r a i n e d amphibole i n c l u d e s r e l i c t  A fine  g r a i n e d amphibole  ject  occurs  ance.  T h i s amphibole  c e n t r e s of pyroxene.  as a c i c u l a r needles  out o f the c o a r s e r amphibole  The  that  and l e n d i t a r a g g e d  i s c o n s i d e r e d t o be a c t i n o l i t i c  pro-  appeari n comp-  osition. Biotite  i s p l e o c h r o i c as f o l l o w s :  c - light  green  a=b - k h a k i  green  The m i n e r a l o c c u r s interstitial  The tially The  to  as e q u a n t b e n t  i n p y r o x e n e and i s  hornblende.  common f e l d s p a r i s a l b i t i c .  as anhedral  I t occurs  g r a i n s t h a t show ' c h e k e r b o a r d  c o m p o s i t i o n ..was f o u n d  occurs  flakes  t o be A n  2  i n some s p e c i m e n s , i t i s l e s s  from  twinning.  1  2V =78-J- . 0  Z  common t h a n  intersti-  K-feldspar  albite.  F i g u r e 28.  Phase I minor f o l d s i n micaceous q u a r t z i t e which plunge eastward at 2 0 ° . On r i d g e n o r t h o f 15 Pup  The  origin  of this rock i s uncertain.  are n o t r e p o r t e d from  the v i c i n i t y  Alternately ogic  this  activity  related  augitite to quartz  i s a metasomatically  quartz d i o r i t e or  to the quartz  r o c k may be a 'made o v e r  features are c o n f l i c t i n g ,  rocks  a n d i t i s assumed t h a t t h e  r o c k i s e i t h e r a b a s i c phase o f t h e g a b b r o i c a phase o f s y e n i t i c  Similar  1  diorite.  basalt.  Mineral-  b u t i t seems l i k e l i e s t altered  gabbroic  that  phase  related  diorite.  STRUCTURAL GEOLOGY  GENERAL STATEMENT  The  structural  geology  l i t h o l o g i c markers and s c a r d i t y to determine  The  to c l a r i f y  basic structural  terms o f t h e l i t h o l o g i c phases o f f o l d i n g  The l a c k o f  o f o u t c r o p make i t d i f f i c u l t  the major s t r u c t u r a l  s t r u c t u r e s has helped  of these  i s complex.  elements.  A study  the s t r u c t u r a l  divisions  s e t out p r e v i o u s l y .  c a n be r e c o g n i z e d i n t h e a r e a .  folds with  separate  folding  wrinkles  on n o r t h w e s t  orientation  phase  history.  p a t t e r n h a s been d e s c r i b e d i n  (Phase I ) was a s t r o n g p h a s e , w h i c h h a s  subisoclinal  o f minor  e a s t t r e n d i n g axes. ( P h a s e l l ) has produced  Two  The f i r s t produced  A l a t e r and open warps o r  t r e n d i n g axes t h a t have a f f e c t e d the  of f o l i a t i o n  only l o c a l l y .  Two i m p o r t a n t  east  41.  trending  faults  trending  f a u l t s w h i c h have had  them and  which have  In cribed  and  features  are  the  recognized  these  are  considerable  a f f e c t e d the  cut  by  later  are  then d e s c r i b e d  on  o r i e n t a t i o n of minor s t r u c t u r e s .  drawn f r o m them. and  north  d i p s l i p movement  f o l l o w i n g pages minor s t r u c t u r e s are  conclusions  are  and  Major  first  des-  structural  a tectonic history i s  presented.  MINOR STRUCTURES  Foliation Most o f the s t r u c t u r e which has thought by  t o be  crystal  only  a few  foliation parallel  exhibit a well  b e e n mapped as  l a r g e l y mimetic  places be  could  the  foliation.  planar  Foliation  is  b e d d i n g and  of mica along  these  marked  planes.  r e l a t i o n s h i p between b e d d i n g  a s c e r t a i n e d , but so.  developed  after original  growth, p a r t i c u l a r l y  or n e a r l y  McTaggart  rocks  i n a l l such cases  Gleitbrett  the  two  structure described  In  and were  by  ( i 9 6 0 ) i n t h e Keno H i l l a r e a t o t h e s o u t h o c c u r s  spar-  The  over  ingly.  the  a t t i t u d e of f o l i a t i o n  e n t i r e area,  northeast fault, east this.  of  but  i n a general  i n that part  while this  they  o f t h e map  are moderate  fault.  The  and  i s by  way  dips  no  means u n i f o r m  are moderate  a r e a west o f H a g g a r t t o the w e s t and  accompanying  t r e n d map  to  the  Creek  northwest  illustrates  Figure  29*  Contoured stereogram,of poles to f o l i a t i o n east o f Haggart Creek f a u l t . The p o l e s f a l l a l o n g a g r e a t c i r c l e whose p o l e c o i n c i d e s w i t h t h e Phase I l i n e a t i o n i n t h e a r e a e a s t of H a g g a r t Creek f a u l t . Note t h e weak t e n dency toward l a t e r a l s p r e a d i n g o f the p o l e s a l o n g a s e c o n d g r e a t c i r c l e whose p o l e c o i n c i d e s w i t h Phase I I l i n e a t i o n s . Lower H e m i s p h e r e , e q u a l a r e a S c h m i d p r o j e c t i o n .  POLES TC FOLIATION EAST OF HAGGART CREEK FAULT  F i g u r e 30.  Contoured stereogram of poles to f o l i a t i o n i n m i c a c e o u s q u a r t z i t e s west o f H a g g a r t C r e e k fault. The p o l e s f a l l a l o n g a g r e a t c i r c l e w h i c h i s somewhere between t h e two l i m i t i n g c i r c l e s shown on t h e d i a g r a m . Lower H e m i s p h e r e , e q u a l a r e a S c h m i d p r o j e c t i o n .  P O L E S TO FOLIATION WEST OF HAGGART  243  plotted  CREEK F-VULT  1  1  |  1  -5 - 1 - 5 V .  |  I  L 5 - 5 •/.  ~]  0  5 -  - -5V.  10 V .  F i g u r e 31»  Contoured stereogram of poles to f o l i a t i o n i n t h e number One v e i n c r o s s c u t . Note the s i m i l a r i t y to f i g u r e 3 » Lower H e m i s p h e r e , e q u a l a r e a S c h m i d p r o j e c t i o n . Q  POLES NUMBER  TO F O L I A T I O N ONE  CROSSCUT  1  1  0 -  2  42  Stereographic for  plots  each of the s t r u c t u r a l  of poles  u n i t s w i t h i n t h e map  area east  o f Haggart Creek f a u l t  cal  which  area,  toward  265° a t 1 8 ° .  the p o l e s at  28  falls  along  quartzites,  i n an  a g r e a t c i r c l e whose p o l e  (See f i g u r e  conforms w e l l w i t h q u a r t z i t e s west  plot  to f o l i a t i o n  78/20.  plot  (See f i g u r e  (See f i g u r e  of poles  u n d e r l a i n by  along a great  30)  (See f i g u r e .  Poles  an e l l i p t i c a l  a g r e a t c i r c l e whose  of Haggart Creek f a u l t .  a t 28°.  t h e number  i n the northern q u a r t z i t e s  were a l s o p l o t t e d  area that f a l l s  t o w a r d 79°  w i t h i n which  few pole  32)  to f o l i a t i o n  g r e y q u a r t z i t e s west  i n micaceous  a l t h o u g h b a s e d on r e l a t i v e l y  shows t h a t p o l e s l i e a l o n g  100/0.  plot  31)  to f o l i a t i o n  of Haggart Creek f a u l t ,  plunges  to f o l i a t i o n  o f Haggart Creek f a u l t  A plot  353°  o f p o l e s t o f o l i a t i o n m e a s u r e d in-  that of poles  One c r o s s c u t l i e s .  trends  plunges  29)  t h e c r o s s c u t on number One V e i n was a l s o made. . T h i s  readings,  ellipti-  spreading of  o f Haggart Creek f a u l t  poles  whose p o l e p l u n g e s  A separate  west  F o r the  a l o n g a g r e a t c i r c l e whose p o l e p l u n g e s t o w a r d  I n t h e a r e a west  circle  were made  area.  such p o l e s p l o t  A weak t e n d e n c y t o l a t e r a l  c a n he n o t i c e d .  micaceous  to f o l i a t i o n  f o r the southern The p o l e s p l o t i n  a l o n g a g r e a t c i r c l e whose  (See f i g u r e  33)  pole  Figure  32.  C o n t o u r e d s t e r e o g r a m o f Phase I l i n e a t i o n and p o l e s t o f o l i a t i o n i n q u a r t z i t e s n o r t h o f B l a c k P h y l l i t e f a u l t and w e s t o f H a g g a r t Creek f a u l t . Lower H e m i s p h e r e e q u a l a r e a S c h m i d p r o j e c t i o n .  P O L E S TO FOLIATION  t  PHASE I  LINEATON  WEST OF HAGGART CREEK FAULT NORTH OF Q L A C K 5 0 poles t o f o l i a t i o n 6 0 lineations plotted  plotted  P H Y L L I T E FAULT  F i g u r e 33«  C o n t o u r e d s t e r e o g r a m o f Phase I l i n e a t i o n and p o l e s t o f o l i a t i o n i n m a s s o i c q u a r t z i t e s west o f H a g g a r t C r e e k f a u l t and s o u t h o f Rex f a u l t , l o w e r Hemisphere, e q u a l a r e a Schmid P r o j e c t i o n .  P O L E S TO FOLIATION PHASE I LINEATION  foliation  I  1 0 - 10% 1 0 - 2 0 « fa  SOUT H OF REX FAULT  > 2 0 •/„ 50 each pi otte d  lineation |  |  0 - 10 10-50'/. > 5 0°/c  Figure  3k.  C o n t o u r e d s t e r e o g r a m o f l i n e a t i o n s o f Phase I i n m i c a c e o u s q u a r t z i t e s west o f H a g g a r t C r e e k fault. Lower H e m i s p h e r e e q u a l a r e a S c h m i d p r o j e c t i o n .  PHASE I LINEATION WES T OF  HAGGART C R E E K  FAULT  Figure  3 5.  C o n t o u r e d s t e r e o g r a m o f l i n e a t i o n s o f Phase I east of Haggart Creek f a u l t . Lower H e m i s p h e r e , e q u a l a r e a S c h m i d p r o j e c t i o n .  PHASE EAST  OF  I  Ll NEATTON  HAGGART  CREEK  FAULT  F i g u r e 36»  C o n t o u r e d s t e r e o g r a m o f l i n e a t i o n s o f Phase I I west o f H a g g a r t C r e e k f a u l t . l o w e r hemisphere, e q u a l a r e a Schmid p r o j e c t i o n .  PHASE E  LINEATION  WEST OF HAGGART CREEK FAULT  +  |  | 0  1  1  -  2°.o  2 - 10V.  43  Lineation  Lineation that  crop  out  structures the  form  is fairly  i n the  occur.  area.  The  w e l l developed  Two  different  commonest  of s t r i a t i o n s  o f them  each of the Por  the  based  of t h i s  lineation  east  poles be  only  with  $0  the  for this  noted  ively  here  readings  and  pole  to the  t h a t the  same t y p e  east  as  so e a s t  of p l o t  34)  figure  pole  to the  A  great  fair  plot  of i t .  (which i s  accurate)  circle  on w h i c h  figure  and  29).  shows  on P o t a t o  foliation It  becomes  should  progress-  Hills  as w e l l  i t i s west o f the  86/12.  (See  the  L i n e a t i o n i s not  shows a w e l l  this  developed  fault.  o f Phase I l i n e a t i o n w e s t defined concentration coincidence  circle  of this  of f o l i a t i o n s  of  at  concentration  (isee f i g u r e  30)  evident.  Por fault  less  of l i n e a t i o n s  Haggart Creek f a u l t  a t 80/20 i s  takes  f i g u r e 35) > w h i c h c o i n c i d e s  great  plunge  is horizontal.  The  the  linear  ( P h a s e I ) were made f o r  (265/l8)(see  area p l o t  east of Haggart Creek f a u l t  with  and  t h e r e f o r e not  (see  s m a l l e r f u r t h e r to the  lineation  (Phase I ) ,  of Haggart Creek f a u l t ,  a c o n c e n t r a t i o n at 272/15, roughly  of  s u b a r e a s f o r w h i c h p l o t s o f f o l i a t i o n were made.  area  on  types  rocks  and m i n u t e w r i n k l e s w h i c h a r e m o s t  p r o m i n e n t west o f H a g g a r t C r e e k f a u l t  Plots  i n most  the n o r t h e r n  q u a r t z i t e s west  a c o n c e n t r a t i o n of l i n e a t i o n s  of Haggart  b a s e d on  scanty  Creek  data  falls  4 4  at  92/0.  (Compare w i t h  through  foliation  100/0  f o r the p o l e  poles here.)  Phase I l i n e a t i o n s Haggart Creek f a u l t  (See  i n the  a l s o based  on  to the g r e a t  southern  the  fall  great  viz.  circle  second  lineation  found  sequence.  The  open t h a n  those  the is  two  (See  7 9 / 2 8 .  The  eographic  than plot  36)  in  the  of  the of  Although area  Minor  to f o l i a t i o n  the  pole  f o r that  area  33)  of l i n e a t i o n  of t h i s  (Phase  lineation  are seen t o g e t h e r striations this  II) i s a  are  o f the  this  wrinkle the  l a r g e r and  first  second l i n e a t i o n  lineation.  the  The  (See  3 2 8 / 2 4 .  observed  i t s orientation uniformly  the  second  throughout  sterof fig-  elsewhere  common enough o r w e l l d e v e l o p e d In general  lineation  f o r the a r e a west  s e c o n d l i n e a t i o n was  analysis.  more Wherever  open w r i n k l e  shows a c o n c e n t r a t i o n a t  enough  to  lineation  the  area.  Polds  Minor f o l d s type  well with  the p r e v i o u s l y d e s c r i b e d l i n e a t i o n .  i t i s not  allow a s t a t i s t i c maintains  type  wrinkles  Haggart Creek f a u l t ure  figure  concentrate  o n l y i n t h e more m i c a c e o u s members o f  lineations  later  on w h i c h p o l e s  q u a r t z i t e s west  data  around 7 2 / 3 2 , which a g a i n c o i n c i d e s f a i r l y to  32)  figure  scanty  circle  is restricted  a r e a are  to a p a r t i c u l a r  Minor folds quartzite  i n the  of f o u r types  p a r t o f t h e map  ( P h a s e I ) a r e commonest  west o f H a g g a r t C r e e k f a u l t .  Two  and  each  area.  i n micaceous  types  of f o l d s  with  45.  p a r a l l e l plunges separate this region into three parts.  The  three parts are subparallel, east-west trending bands, whose boundaries are not defined well enough to be mapped.  In the  northern and southern bands which are both wider than the central band, minor folds have north up and over south sense. In the narrow central band minor folds are much less abundant than they are i n the marginal bands and where their sense i s evident i t i s opposite ( i . e . south up). Although the minor folds are of opposite senses t h e i r style i s identical.  (See figures 58, 39> 40)  are c y l i n d o i d a l and s i m i l a r .  Both f o l d types  The attitude of t h e i r axes i s con-  stant, but the a x i a l planes of minor folds show considerable v a r i a t i o n i n dip and s t r i k e .  The poles of attitudes of those  few a x i a l planes that were measured f a l l near the great c i r c l e containing poles to f o l i a t i o n . tions i n attitudes;  Limbs of folds also show v a r i a -  this i s r e f l e c t e d i n the fact that there  i s only one zone of concentration on the plot of poles to f o l i a tion.  The average angle between limbs of minor folds varies  from 90° to 3 0 ° , but averages about 45°•  Thickening at the  hinge with thinning on the limbs has occurred and the thinning r a t i o i s about ls.2 for most minor f o l d s . well rounded.  A l l f o l d hinges are  A x i a l plane cleavage i s very poorly developed  i n most minor f o l d s .  R e c r y s t a l l i z a t i o n along the a x i a l planes  of minor folds has occurred and i s p a r t i c u l a r l y prominent i n mica r i c h rocks.  Lineation p a r a l l e l to f o l d axes occurs  F i g u r e 37.  Phase I m i n o r f o l d s o f McGann C r e e k .  i n grey p h y l l i t e  north  F i g u r e s 38,  39, 40. C r o s s - s e c t i o n s of minor f o l d s of ffiase 1 f r o m v a r i o u s p a r t s o f t h e map area. The c r o s s - s e c t i o n s a r e p e r p e n d i c u l a r to t h e p l u n g e o f t h e f o l d s and a r e o r i e n t e d so t h a t n o r t h i s on t h e l e f t and s o u t h on the right. Stipples indicate quartzite. Black i n d i c a t e s massive white quartz. Dashes i n d i c a t e g r e y p h y l l i t e .  PHASE I  5 feet  MINOR  FOLDS  10 feet  PHASE  I  MINOR FOLDS  6 j n6  3  in-  in  7  2 feet  —  1 foot  in  Figure  41.  C o n t o u r e d s t e r e o g r a m o f Phase I f o l d a x e s west o f H a g g a r t C r e e k f a u l t . Note p a r a l l e l ism t o f i g u r e 34. Lower h e m i s p h e r e , e q u a l a r e a , S c h m i d p r o j e c t i o n .  PHASE I W E S T OF  FOLD  AXES  HAGGART C R E E K  ( in number one  vein  FAULT  crosscut)  46.  on  the l i m b s  the  o f the m i n o r f o l d s ,  crosscut should  stereographic plot  noted  quartzite  ( 8 6 / 1 2 ) and  on w h i c h p o l e s t o f o l i a t i o n  third  type  Creek f a u l t  of minor f o l d  i n the a r e a west of Haggart type  a r e uncommon, b u t  a description: north-east. hinges  their  The  sense  folds  are  a r e - w e l l rounded.  attitudes  of the  observed  and  at about  100°.  type  described  No  41)  to the  It concen-  the  f o r the m i c a c e o u s  concentrate  (80/20).  I I ) c a n be  Creek f a u l t .  open and  One  Minor  recogfolds  of  to a l l o w  up w i t h r e s p e c t t o  cylindroidal  and  their  fold  T h e i r a x i a l ^planes d i p g e n e r a l l y t o 60°  and  limbs are f a i r l y  plunges  and  about  170°.  c o n s t a n t i n those  folds  strike  i s also  fairly  t h i n n i n g has  to the northwest  o f them were o b s e r v e d  t h e y a p p e a r t o be  parallel  t o the  constant  occurred.  a t moderate  This angles  f o r stereographic second  lineation  above.  Minor different  features  figure  to the pole of  i s south-west  t h i c k e n i n g and  t o o few  (See  (Phase  t h e a n g l e between l i m b s  of f o l d  although  analysis  are  on  the number  enough o f them a r e p r e s e n t  the west a t a n g l e s between 40°  third  axes f r o m  this concentration i s close  west o f H a g g a r t  A  this  that  o f Phase I l i n e a t i o n  great c i r c l e  nized  of f o l d  shows a c o n c e n t r a t i o n a t 83/22.  be  tration  and  i t i s generally lacking  hinges.  A  The  but  folds  from  o f P h a s e I west o f H a g g a r t  those  distinguish  Creek  fault  o f t h a t phase e a s t o f the f a u l t .  them.  The  first  i s their  orientation.  Two  F i g u r e 42.  C o n t o u r e d s t e r e o g r a m o f p o l e s to .joints i n metamorphic r o c k s west o f H a g g a r t Creek fault. Note p a r a l l e l i s m to f i g u r e 3 4 & 4 1 . Lower H e m i s p h e r e e q u a l a r e a S c h m i d p r o j e c t i o n .  POLES WEST  TO J O I N T S  METAMORPHIC ROCKS OF H A G G A R T C R E E K FAULT |  |  0 -  fl.  F i g u r e 43.  C o n t o u r e d stereogram o f p o l e s t o .joints i n metamorphic r o c k s e a s t o f H a g g a r t Creek f a u l t . Note t h a t the dominant j o i n t s e t c o i n c i d e s w i t h Phase I I l i n e a t i o n (see f i g u r e 36JT Lower Hemisphere e q u a l a r e a Schmid p r o j e c t i o n .  POLES TO JOINTS METAMORPHIC ROCKS EAST OF HAGGART CREEK FAULT  47.  East  o f the  angles Too  f a u l t minor f o l d s  i n c o n t r a s t to  few  observations  a stereographic their  axes are  the  eastward plunge  a n a l y s i s of a x i a l parallel  i s i n the  This  v a r i e s from  to the  angle 50°  minor f o l d s  a r e more i s o c l i n a l  iable  o f i t , and thinning 1:4. than  east  t h e r e has  on  the  are  are west  where r e p e a t e d  and  o f the  fold  fault  b e e n more  limbs.  Fold, h i n g e s they  plane  than  ' The  of minor  East  those limbs  than  are  they  The  att-  somewhat l e s s  var-  are  for folds  t h i c k e n i n g at the hinge  many t i m e s  so  minor f o l d s  that their  in  fault  west o f i t .  a l s o somewhat s h a r p e r The  second folds.  o f the  F o l d s have a t h i n n i n g r a t i o  of i t .  however,  averages about 3 0 ° ,  of Haggart Creek f a u l t .  axial  for folds  and  limbs  allow  areas;  Phase I l i n e a t i o n .  t o 15°  east  o f the  shallow  o f f o l d s west o f i t .  trend i n both  between the  minor f o l d s  itudes  to the west a t  o f t h e s e m i n o r f o l d s were made t o  difference angle  plunge  east  and  of  about  o f the  are n e a r l y  sense i s not  west  fault  everyclear.  Joints  The detail.  p a t t e r n of j o i n t i n g has  Stereograms showing  been s t u d i e d i n some  the  poles  to j o i n t  planes  been p l o t t e d f o r t h e m e t a m o r p h i c  rocks  e a s t and  west  Haggart Creek f a u l t . around  two  t o compare  points at these  with  poles  to f o l i a t i o n  great  circle  172/76 W and  of t h i s  fault  58/60 SE.  of  concentrate  It is  interesting  170/80 ¥ f o r t h e g r e a t c i r c l e on w h i c h  f o r this area  to which  (Phase II') i n t h i s  J o i n t s west  have  the  area  plot  and  with  48/66 SE f o r t h e  c o n c e n t r a t i o n o f the l a t e  i s the  pole.  (See  figure  lineation 4-2)  Figure  44*  C o n t o u r e d s t e r e o g r a m o f p o l e s t o .joints i n g r a n i t i c rocks e a s t o f Haggart Creek f a u l t . Lower H e m i s p h e r e e q u a l a r e a S c h m i d p r o j e c t .  POLES TO JOINTS GRANITIC ROCKS EAST OF HAGGART CREEK FAULT |  | 0 - 5»/c  |  1 5-10 /c e  •  5 0 plotted  T  > io°/  0  48.  E a s t o f Haggart Creek f a u l t j o i n t s i n the metamo r p h i c r o c k s c o n c e n t r a t e around 7 3 / 6 ? S and 1 7 0 / 9 0 .  The  a n g l e between Phase I plunge d i r e c t i o n and the p o l e t o the s t r o n g e s t j o i n t s e t e a s t o f Haggart'Creek f a u l t i s 6 3 ° , compares w i t h 70°  which  f o r the a n g l e between Phase I plunge d i r -  e c t i o n and the p o l e t o the second s t r o n g e s t j o i n t s e t west o f the f a u l t .  43)  (See f i g u r e I n the g r a n i t i c  r o c k s e a s t o f H a g g a r t Creek  fault  are two j o i n t s e t s w h i c h c o n c e n t r a t e around 90/70S and 0 / 9 0 . Though o n l y a few j o i n t s were measured  i n the g r a n i t i c  rocks  west o f H a g g a r t Creek f a u l t these seem t o conform w i t h the set  0/90.  (See f i g u r e  44}  Conclusions S e v e r a l c o n c l u s i o n s can be drawn from the f o r e g o i n g descriptive 1.  section.  Only two phases o f f o l d i n g (Phase I and Phase I I )  can be r e c o g n i z e d i n the a r e a . than Phase I may  A phase o f f o l d i n g  earlier  be p o s t u l a t e d t o have produced the b e d d i n g  p l a n e f o l i a t i o n , but f o l d s o f t h i s e a r l y phase would o f necessity  be i s o c l i n a l and recumbent and are u n r e c o g n i z a b l e .  No  m i n o r f o l d s to s u p p o r t such an e a r l y i s o c l i n a l phase are found and l i n e a r s t r u c t u r e s , u n l e s s p a r a l l e l and i d e n t i c a l lineation  are l a c k i n g .  t o Phase I  I t i s p o s s i b l e t h a t the f o l i a t i o n may  have been formed by s t r o n g s h e a r i n g p a r a l l e l to the o r i g i n a l d i n g o f the r o c k w i t h o u t much o r any f o l d i n g .  also bed-  2. is  The f i r s t  o f t h e two  by f a r t h e s t r o n g e s t  phases of f o l d i n g ,  folding  phase.  (see f i g u r e s 38,  i s o c l i n a l minor f o l d s  Phase  I,  I t has produced sub39,  40) on e a s t  trending  axe s. 3.  The  rocks west isoclinal  reversal  i n s e n s e o f Phase  o f Haggart Creek f a u l t fold  Creek f a u l t ;  i n the micaceous this  I minor f o l d s i n  suggests a l a r g e  q u a r t z i t e s west  s u g g e s t i o n i s s u p p o r t e d by  sub-  of Haggart  foliation  trends here.  4.  lineations  o f Phase  1 are p a r a l l e l  t o Phase  I  fold  axes. 5.  Phase  tation  of f o l i a t i o n  6. east Phase  Foliation  west  accounts f o r the v a r i a t i o n of Haggart Creek  outlines  a b r o a d west  of Haggart Creek f a u l t . I structure  of g r a n i t i c  7.  The  between  o f Phase faults.  plunging  antiform  i s probably  been m o d i f i e d by  a  intrusion  and s o u t h o f t h e m i c a c e o u s  o f H a g g a r t C r e e k f a u l t have been b u t Phase  I fold  s u b j e c t e d to  axes i n t h e s e r o c k s  o r i e n t a t i o n s from those i n the micaceous  them, b e c a u s e  micaceous  fault.  This antiform  have  quartzites north  I folding,  different  t h a t may  i n orien-  rocks i n i t s core.  q u a r t z i t e s west Phase  I folding  rocks.  The  I indicate  t h e y a r e s e p a r a t e d by f a u l t s differences  t h e movement  i n orientation that has  have  quartzites from the  of f o l d  axes  o c c u r r e d on t h e s e  50.  8.  Jointing  Creek f a u l t joint of  i n the metamorphic  i s related  t o Phase  sets are present.  joints  II folding.  Two  p e r p e n d i c u l a r t o t h e plunge o f Phase I l i n e a r  set.  o f Phase  I and Phase  The p r e d o m i n a n t one by f a r i s a s e t  s t r u c t u r e s and i s t h e r e f o r e joint  r o c k s west o f H a g g a r t  referred  The w e a k e r j o i n t  II linear  t o a s a Phase I ' a c '  s e t i s p e r p e n d i c u l a r t o the plunge  structures  and i s c o n s i d e r e d a s a Phase I I  'ac' j o i n t s e t .  9.  A s e c o n d weak p h a s e  urred.  Minor folds  of this  (Phase I I ) o f f o l d i n g has o c c -  phase a r e w r i n k l e s  n o r t h w e s t w a r d and h a v e n o t a f f e c t e d foliation  t o any m a r k e d d e g r e e .  10.  Two  the map  sets  area.  as a r e s u l t  affected related turing sets  rocks  and a r e t h e r e f o r e  of a separate  the metamorphic to cooling  along  rocks.  11.  considered  dev-  This  s t r e s s p a t t e r n may be  o f t h e g r a n i t i c mass w h i c h r e s u l t e d The two  i n fracjoint  t o the form o f the  intrusion.  of joints  are developed i n the metamorphic  o f Haggart Creek f a u l t .  these i s c o n s i d e r e d second  t o have  s t r e s s p a t t e r n that has not  two a l m o s t p e r p e n d i c u l a r p l a n e s .  Two s e t s  rocks east  rocks i n  those o f the surround-  do n o t show any o b v i o u s r e l a t i o n s h i p  granodiorite  attitude of  are developed i n g r a n i t i c  They do n o t c o i n c i d e w i t h  i n g metamorphic eloped  of joints  the o v e r a l l  that plunge  strongest  By f a r t h e s t r o n g e s t o f  t o be t h e P h a s e I I ' a c  joint  1  joint  s e t i s perhaps t h e Phase  set.  The  I 'ac' j o i n t  51.  set. of  No e x p l a n a t i o n i s s u g g e s t e d  f o r the t h i r d ,  v e r y weak, s e t  joints.  12.  The f a c t  Haggart  Creek  more p r o m i n e n t  t h a t Phase I I l i n e a t i o n  fault  and t h a t  here  i s lacking  t h e Phase I I ' a c ' j o i n t  than i t i s west o f the f a u l t  east of set i s  suggests  that  t h e r m a l metamorphism h a s d e s t r o y e d t h e Phase I I l i n e a t i o n , b u t that and  this  folding  perhaps  also  phase h a s c e r t a i n l y  more s t r o n g l y  a c t e d on t h e s e  than west o f the f a u l t .  s u p p o r t e d by t h e t e n d e n c y  rocks  This i s  of poles to f o l i a t i o n  i n this  a r e a t o s p r e a d a l o n g t h e g r e a t c i r c l e whose p o l e c o i n c i d e s where t h i s l i n e a t i o n lineations  are also  than t h e y a r e west  s h o u l d be were i t n o t d e s t r o y e d . l e s s common e a s t o f H a g g a r t  Creek  with  Phase I fault  of i t .  MAJOR STRUCTURES Folds  That l a r g e  scale  folds  are d i f f i c u l t  t h e map a r e a i s due t o t h e g e n e r a l l a c k horizons. and  T h e i r presence  The line but  grey p h y l l i t e s  what a p p e a r s the a c t u a l  observed  o f outcrop and marker  i s however s u g g e s t e d  abundance o f m i n o r s t r u c t u r e s  that  to o u t l i n e i n  by t h e n a t u r e  occur i n the a r e a .  west o f Haggart  Creek  t o be a n e a s t p l u n g i n g , recumbent  j u n c t i o n o f t h e two g r e y p h y l l i t e  so t h a t  this  fold  i s not a certainty.  fault  out-  synform,  bands was n o t  52.  Trends o f f o l i a t i o n fold the is  i n the micaceous opposite  referred  senses  o f minor f o l d s  support  trend  o f Haggart Creek f a u l t  line  a broad,  from  t h e t r e n d map.  an eastward  plunging  q u a r t z i t e s west o f H a g g a r t C r e e k and  to the accompanying  East  or core  outline  open, w e s t w a r d p l u n g i n g  this.  The  reader  map.  trends  of f o l i a t i o n  antiform.  The g r a n o d i o r i t e s t o c k  This i s evident  occupies  i t s hinge  a n d i t s s h a p e a p p e a r s i n a g e n e r a l way t o c o n f o r m  the h o s t  rock  structure. along  The f a c t  a great c i r c l e  that poles  with  to f o l i a t i o n i n  this area  fall  the Phase  I lineation  structure  that l o c a l i z e d  i n f u s i o n of granodiorite along i t s  Several  c u t the area.  suggests  whose p o l e  out-  that this  fold  coincides with i s a Phase I  core.  Faults  these, in  faults  the Haggart Creek f a u l t ,  the foregoing d i s c u s s i o n .  fault  and i t s c o u n t e r p a r t ,  has a l r e a d y f i g u r e d  Other f a u l t s  cross-fault,  and  t h e McGann C r e e k c r o s s - f a u l t .  observed.  t h e Rex f a u l t ,  t h e Rex f a u l t ,  The o t h e r  t h e i r presence  faults  fault,  the F i f t e e n  Of t h e s e  only  the Haggart  and t h e F i f t e e n Pup f a u l t do n o t c r o p  c a n o n l y be i n f e r r e d  the evidence  prominently  the Secret Creek C r o s s - f a u l t ,  from  have  been  o u t i n t h e a r e a and structural  In the f o l l o w i n g s e c t i o n the f a u l t s and  of  are' t h e T i n H i l l  the B l a c k P h y l l i t e  Pup  Creek f a u l t ,  The m o s t i m p o r t a n t  evidence.  are described  f o r t h e i r existence i s s e t out.  Aside  from  53  these major These  faults several  latter  inferred  ones  from  smaller  are not d e s c r i b e d :  t h e map,  to which  out  the f o l l o w i n g  discussion,  a.  Haggart Creek  Fault  The tural the soft  A  consequent  on t h e g r o u n d  gouge zone  Creek, 1 m i l e  below  Gill  t h e gouge zone  valley  Gulch.  The  the f a u l t  Evidence the  of  f o r the e x i s t e n c e  Gouge Z o n e .  2.  Displacement of l i t h o l o g i c  the  struc-  fault  of Haggart been  ex-  on e i t h e r  side  follows  the  i t h a s b e e n named.  It  Creek.  o f the f a u l t  consists  of  b o u n d a r i e s on e i t h e r  side  fault. Pronounced  fault  structural differences  i n the form trends•of  attitudes 4.  the  The  Rocks  l o c a l i z e d Haggart  1.  foliation, and  through-  following.  3. the  gouge zone h a s cut.  were n o t e x p o s e d .  that  i n f e r r e d from  f e e t wide i n t h e bottom  of Haggart Creek a f t e r which  seems l i k e l y  was  be  i n the f i n d i n g o f a b l e a c h e d ,  p o s e d h e r e by a 2 0 - f e e t - w i d e p l a c e r of  t h e i r n a t u r e may  s e a r c h f o r some i n d i c a t i o n o f  resulted  a t l e a s t 20  observed.  the reader i s r e f e r r e d  presence of t h i s f a u l t  evidence.  fault  f a u l t s h a v e been  of  of markedly Phase  I minor  on e i t h e r s i d e  different attitudes fold  of  p l u n g e s and l i n e a t i o n s  joints.  Displacement of the T i n H i l l - B l a c k P h y l l i t e  Haggart Creek  of  fault.  fault  by  54  The inferred on  d i p o f the f a u l t  from  the f a u l t  i t s outcrop  logic b.  map  t o be l a r g e l y  The amount o f movement  crops  east of Haggart Creek.  dipslip  estimated  o u t on t h e s o u t h  The T i n H i l l  i s c u t o f f by H a g g a r t C r e e k  The  fault  fault  to  and d i p n o r t h e a s t  and d i p m o d e r a t e l y  That due  the p o s i t i o n  to the lack of outcrop  ever i t s a c t u a l p o s i t i o n map.  The assumed o u t c r o p  fault  surface.  largely  North  of the f a u l t ,  fault.  c.  Fault  Black P h y l l i t e  This f a u l t , described  that strike  from  which  which  r o c k s , which  trends strike  South o f t h i s  more o r l e s s  parallel  northwest.  o f the f a u l t on t h e s o u t h  i s probably  i s not w e l l defined i s slope of T i n H i l l .  How-  c l o s e t o t h a t shown on t h e  p a t t e r n suggests  or s c i s s o r - l i k e  the B l a c k P h y l l i t e  fault,  t o be  o u t anywhere, b u t i t s p r e -  The movement on t h e f a u l t  rotational  slopes of T i n H i l l  a t moderate a n g l e s .  are micaceous q u a r t z i t e s  the f a u l t  t h e geo-  i s thought  somewhat n o r t h o f e a s t , a r e b l a c k p h y l l i t i c  fault  from  fault.  does n o t c r o p  i s a geologic necessity.  northwest  and down  feet.  e a s t e r n e x t e n s i o n o f the B l a c k P h y l l i t e  sence  o f movement  Fault  This f a u l t  it  The s e n s e  i s o f t h e o r d e r o f one t h o u s a n d  TinHill  the  pattern.  i s considered  on t h e e a s t .  i s n o t known, n o r c a n i t be  a south  d i p o f the  i s inferred  t o be  on t h e b a s i s o f movement on  the c o u n t e r p a r t o f the T i n H i l l  above, i s w e s t o f H a g g a r t C r e e k .  fault,  No o u t c r o p s  of i t  55.  were s e e n , position it  but i t s presence  i s limited  a t two p l a c e s .  fairly  i s s t r u c t u r a l l y necessary closely  The f a u l t  by o u t c r o p s  trends southeast.  black p h y l l i t i c  rocks i n which f o l i a t i o n s  strike  to the f a u l t  zites  parallel strike  east.  parallel  to the f a u l t ,  about  while  on e i t h e r North  side of  of i t are  d i p n e a r v e r t i c a l and  south o f i t micaceous but d i p moderately  L i n e a t i o n s o f Phase I n o r t h o f t h e f a u l t  t o i t and have no p l u n g e , plunge  while  and i t s  lineations  trend  quart-  northparallel  south of the f a u l t  10°north o f e a s t a t r o u g h l y 20°.  Prom t h i s  i n f o r m a t i o n t h e movement  a p p a r e n t l y been s c i s s o r l i k e w i t h r o t a t i o n b l o c k e a s t up, west down, r e l a t i v e  on t h e f a u l t h a s  o f the n o r t h e r n  to the south b l o c k .  The  amount o f movement must have b e e n v a r i a b l e .  Prom t h e o u t c r o p  pattern  t o be s t e e p l y t o  the d i p o f the f a u l t  the  south,  d.  Rex P a u l t Rex  offset  fault,  by s e v e r a l  northward  i n the southwest  other f a u l t s ,  a t an a n g l e  w a l l and h a n g i n g  o f about  supported  60°.  Good o u t c r o p s f o r study.  by t h e d i r e c t i o n  North  itself  o f the f o o t  S l i c k e n s i d e s on  t h a t l a s t movement h a s been d i p s l i p  and t h a t i t h a s b e e n n o r m a l .  on t h e f o o t and h a n g i n g  o f t h e map a r e a ,  t r e n d s r o u g h l y e a s t and d i p s  w a l l are a v a i l a b l e  the f o o t w a l l i n d i c a t e entirely  c a n be i n f e r r e d  almost  Normal movement i s a l s o  of drag of f o l i a t i o n  i n the w a l l rocks  walls.  o f the f a u l t  are micaceous q u a r t z i t e s which d i p  56  northward moderately while  the  d i p south  o f the  d o m i n e n t l y more e a s t w a r d a t s i m i l a r a n g l e s generally erences cribed  l e s s micaceous  i n plunge  amount o f movement on  cross-fault  In a b u l l d o z e r cut n o r t h  stained walls  gouge zone a t l e a s t  are not  ment on  e x p o s e d and  i t are not  fault  the  fault  i s thought  are  the  that  are  fault.  a l s o noted,  the Rex  the  known.  t o be  south  than  crops  fault  out  Diffas  des-  i s not  known.  place  i n the  a t one  o f F i f t e e n Pup  thirty  the  fault  outcrop  and  the  O f f s e t on  s t r i k e s l i p with  i n t h e n o r t h where t h e  The  t h e move-  pattern of  nearly vertical.  largely  a limonite  f e e t wide i s e x p o s e d .  d i p o f the  From  dip i s apparently  ment i n t h e  the  l a r g e r movefault  apparently  out. S e c r e t Creek F a u l t Secret Creek f a u l t  does n o t  crop  out  discontinuity Rex  of  pre-  F i f t e e n Pup C r o s s - f a u l t  area.  f.  north  o f Phase I l i n e a t i o n  F i f t e e n Pup  dies  those  i n rocks  is  above. The  e.  than  fault  vault.  o f the  order  linear  i n the a r e a :  of l i t h o l o g i c  I f movement h a s of twenty-five  upthrown s i d e .  n e a r the  e c t e d , whereas i t has  either  edge o f t h e  i t s presence  u n i t s and  side of t h i s  offset  of  from the  i t s m a g n i t u d e must  hundred f e e t , w i t h to note  area  i s inferred  apparent  been d i p s l i p  It i s surprising  s t r u c t u r e s on  west  that  the  b e e n c h a n g e d m a r k e d l y by  east being  the p l u n g e  f a u l t has an  be  not  the  of  been  apparently  aff-  57  s m a l l e r movement i n t h e c a s e o f H a g g a r t C r e e k f a u l t . reason f o r t h i s  s e e m i n g d i s c r e p a n c y may  o f t h e movement  on t h e f a u l t  it g.  was on H a g g a r t C r e e k McGann C r e e k  be t h a t  was d i f f e r e n t  the n a t u r e  on t h i s  fault  its  Fault  t w e n t y d e g r e e s west  of quartz in due  o f n o r t h and w h i c h ,  o u t c r o p p a t t e r n must have a n e a r v e r t i c a l  does n o t c r o p  out, but i t o f f s e t s  feldspar  the n o r t h  likely  porphyry.  Rex f a u l t  at i t s north  t h a t movement h a s b e e n l a r g e l y  from fault  and t h e two d y k e s  The amount o f o f f s e t  out o f the f a u l t  which  d i p . The  than i t i s i n the south, an e f f e c t  to the dying  than  fault,  West o f S e c r e t C r e e k i s y e t a n o t h e r f a u l t , trends about  The  i s smaller  t h a t may be end.  I t seems  strikeslip.  TECTONIC HISTORY The  tectonic  the s t r u c t u r a l chronological 1. trending 2.  history  features described order  Phase  above.  from  I t i s presented i n  below.  I folding  t o produce f o l d s  on g e n t l y e a s t w a r d  axes. Phase  by a l i n e a t i o n  II folding,  a v e r y weak p h a s e r m a r k e d  and a n ' a c ' j o i n t  developed  s e t o f 'ac' j o i n t s ,  foliation  much.  3.  Intrusion  fault.  o f t h e a r e a c a n be d e d u c e d  i n t h e west  s e t a,nd i n t h e e a s t b y a w e l l  d i d not a f f e c t  o f the g r a n i t i c  the o r i e n t a t i o n of  stock east  o f Haggart Creek  58  k.  Faulting,  faults  with  direction with and  the  various  along  two  western  producing  first  in  an  east  types  of  movement  other  faults  to  direction  along  and l a t e r  disrupt  block  moving  up  relative  a marked  change  in  plunge  the  to  in  in  two  a  north  whole  the  major  pattern,  eastern  Phase  I  one  linear  structures.  STRUCTURAL F I T WITH P A T T E R N S  south  of  A  brief  the  map  structures diagram  are  of  those  the  do  in  but  to  those  the  plunge  I  in  is  direction  are  the  in  map  Phase of  McQuesten  given  structural  in  the  those  in  incorporates  area  south  itself.  northward  map  features  following the  some  IDEAS  to  the  section.  map  area.  ideas  of  The  the  The block  general  areas  of  the  map  area  are  Foliation north at  shallow  to  similar  of  South  moderage  angles  area.  linear  generally  Plunge  of  SOME  area.  dips  Phase l l e l  III)  the  river  those  is  structures  within  McQuesten as  area  compared w i t h  Minor to  description  (Appendix  structure  TO T H E SOUTH::.  structures  to  the  south  shallower  reversals  are  in  the  map  as  far  as  than  it  observed  is  area  are  McQuesten in  the  to  the  south  the  map  area  map as  paraRiver, area. they  area.  I minor folds  River  are  more  south  of  isoclinal  than  those  in  and the  north map  area  and  their  map  area.  sense i s o p p o s i t e  to t h a t g e n e r a l l y observed  Phase I I l i n e a t i o n s the  south  than  they  its  d i r e c t i o n are constant  map  area.  Jointing pattern being  similar  the  'ac*  are  it  area  itself.  Keno H i l l  north that  o f Phase  area,  the  area are  out.  Galena H i l l s  rocks  The  and  predominant  these minor s t r u c t u r e s are  ( n o r t h up vicinity are  and  i s thought over  south  similar  section  opposite  to those north  in of  immediately identical  to  structurally higher,  or  conformable  on  them.  t h a t the  area i s considered genetically  opposing  i n t h e map  limbs  evidence  related.  sense of minor  a r e a and  s o u t h up  of South McQuesten R i v e r ) i s evidence on  set  o f Phase I minor s t r u c t u r e s from  S o u t h M c Q u e s t e n R i v e r t o t h e map  It  the  a r e more o r l e s s  parallelism  the  a r e a shows a  t o S o u t h M c Q u e s t e n R i v e r and  Q u a r t z i t e crops  on Keno and  The  areas  o f the map  and  I.  o f t h e map  Close  to  from South McQuesten R i v e r to  south  the  Both the plunge  o f 'South M c Q u e s t e n R i v e r i s l i t h o l o g i c a l l y  more n o r t h e r n  that  area.  to t h a t w i t h i n the  Rocks s o u t h the  a r e much commoner i n r o c k s  i n t h e map  i n areas  joints  in  in  t h a t the  o f a l a r g e recumbent Phase  folds the two  I  fold.  6o  The  abrupt  change i n sense of Phase I minor f o l d s a c r o s s the  Lynx Creek-Haggart Creek v a l l e y i s c o n s i d e r e d evidence p o s s i b l e f a u l t along t h i s  for a  valley.  Decreased i n t e n s i t y o f Phase I I f o l d i n g t o the n o r t h i s thought to account f o r the p r o g r e s s i v e l a c k of Phase I I s t r u c t u r e s i n areas  successively further north.  The c e n t r e of  h i g h e s t i n t e n s i t y o f Phase I I f o l d i n g i s thought to be i n the v i c i n i t y o f South McQuesten R i v e r . The McQuesten a n t i c l i n e  (Bostock  1947)  i s considered  to be a f a u l t which has had a l a r g e amount o f d i p s l i p movement on i t (south s i d e up) r a t h e r than a f o l d .  Opposing d i p s , n o r t h -  ward n o r t h o f t h i s f a u l t and southward south of i t , to be the r e s u l t of t h i s f a u l t .  are thought  I t i s f u r t h e r considered  that  the McQuesten ' a n t i c l i n e ' i s o f g e o l o g i c a l l y recent o r i g i n and t h a t minor s t r u c t u r e s i n the area are g e n e t i c a l l y and tempora l l y u n r e l a t e d to i t .  METAMORPHISM  GENERAL STATEMENT The  rocks have been s u b j e c t e d to weak r e g i o n a l  metamorphism and i n the e a s t e r n s e c t i o n a l a t e phase o f  Figure —  45.  ACF d i a g r a m f o r q u a r t z - a l b i t e - m u s c o v i t e - c h l o r i t e s u b f a c i e s o f g r e e n s c h i s t r e g i o n a l metamorphic f a c i e s f o r rocks w i t h excess SiOp. Coloured s e c t i o n s r e p r e s e n t a s s e m b l a g e s f o u n d i n the a r e a .  61.  moderate  t h e r m a l metamorphism h a s been  regional  metamorphism.  Metasomatism to g r a n i t i c  s u p e r i m p o s e d on t h i s  a p p e a r s t o be l i m i t e d t o r o c k s  close  contacts.  REGIONAL METAMORPHISM  Mineral  assemblages  of Haggart Creek f a u l t  i n the metamorphic  are very uniform.  Typical  rocks  west  assemblages  are: Quartz^muscovite-chlorite-albite Quartz-muscovite=chlorite Quartz-museovite Hornblende-albite-chlorite-stilpnomelane-quartz These of  assemblages  r e g i o n a l metamorphism and f i t i n t o  vite-chlorite reproduced  subfacies.  i n micaceous albite.  for  facies  the q u a r t z - a l b i t e - m u s c o -  An ACE diagram f o r t h i s s u b f a c i e s i s  i n figure 4 5 . East  in  are c h a r a c t e r i s t i c of the greenschist  This  of Haggart Creek f a u l t  quartzites assemblage  the t y p i c a l  assemblage  i s quartz-biotite-muscovite-chloritefits  the greenschist  f a c i e s and belongs  the q u a r t z - a l b i t e - e p i d o t e - b i o t i t e - s u b f a c i e s . t h i s f a c i e s i s reproduced i n f i g u r e 4 5 . l  An AKE diagram '(\  62.  The f a c t  t h a t the metamorphic r o c k s  Creek f i t a s l i g h t l y considered rocks  higher  due t o t h e e f f e c t s  by i n t r u s i o n  clear.  impure  o f thermal  metamorphism  on t h e s e  stock.  o f the m i c a c e o u s q u a r t z i t e s and p h y l l i t e s  These l o w g r a d e ,  originally  o f r e g i o n a l metamorphism i s  o f the g r a n o d i o r i t e  The o r i g i n is  grade  east of Haggart  r e g i o n a l l y metamorphosed  s a n d s t o n e s and q u a r t z  rich  shales  rocks  were  or siltstones.  THERMAL METAMORPHISM T h e r m a l metamorphism Creek.  The e f f e c t s  o f thermal  of  the g r a n o d i o r i t e stock  is  n a r r o w e r on t h e n o r t h  North o f the quartz metamorphism rocks  is are  low  five  diorite  stock  hundred f e e t  metamorphic  are l i s t e d  which  they  and s o u t h  from  aureole  belong.  side.  signs o f thermal of andalusite i n  the g r a n i t i c  contact.  o f c o n t a c t metamorphism  metamorphic  occur  assemblages  a s s e m b l a g e s and t h e  grades imperceptibly i n t o  the normal  zone.  of minerals  below with  aureole  i t i s on t h e s o u t h  the f i r s t  effects  to low thermal  Assemblages  to  s i d e o f i t than  grade r e g i o n a l metamorphic  stock  north  t o d e f i n e s i n c e l o w r e g i o n a l metamorphic  so s i m i l a r  thermal  metamorphism  east o f Haggart  a r e t h e same, b u t t h e t h e r m a l  a t which the f i r s t  difficult  only  a r e i n d i c a t e d by t h e a p p e a r a n c e  at least  The l i n e  i s marked  found  the f a c i e s  i n the rocks n e a r the o f thermal  metamorphism  Figure  46.  AKF d i a g r a m f o r h o r n b l e n d e h o r n f e l s t h e r m a l metamorphic f a c i e s r o c k s w i t h excess S i O ? . C o l o u r e d s e c t i o n s r e p r e s e n t assemblages found i n the a r e a .  63.  Assemblages Minerals  are  i n order  i n the A n d a l u s i t e  Hornfels  Unit  o f abundance i n w h i c h t h e y  occur  i n each  assemblage. 1.  Quartz-biotite-muscovite.  2.  Quartz-biotite-muscovite-andalusite.  3.  Biotite-muscovite-andalusite.  4. Q u a r t z - c o r d i e r i t e - b i o t i t e . 5. Q u a r t z - a n d a l u s i t e - c o r d i e r i t e - b i o t i t e - s i l l i m a n i t e - m u s c o v i t e . 6.  Quartz-cordierite.  7.  Biotite-muscovite-quartz-corundum.  8.  Quartz-K-feldspar-muscovite-corundum-biotite.  The  first  hornblende-hornfels produced  s i x of these facies  conclusions  The  assemblages are  are  d e r i v e d from q u a r t z  of s i m i l a r chemical Greek f a u l t  during  with  facies:  a l l iron  they  a l l the  this  f i t one  were r e a c h e d  The  during  be  the  diagram i s r e -  drawn f r o m  deficient  rich,  pelitic  are  t o the  and and  silica  rocks  probably  this  rich.  facies well  They and  are  west o f H a g g a r t  correlatives.  a s s e m b l a g e s f i t i n the  A corollary  information.  arkosic rocks  i n d i c a t e s a uniform  t h e r m a l metamorphism.  assemblages  can  composition  which  discrepancies  hornf els  f o r w h i c h the AKF  to  in figure 46. Several  small  assemblages belong  for  hornblende-  temperature o f the  But  fact  distribution that  the  i s that equilibrium conditions  t h e r m a l metamorphism.  presence  of s i l l i m a n i t e  i n some a s s e m b l a g e s  from  64  rocks very c l o s e to the g r a n i t i c higher  temperature  i n which  contact indicates  conditions existed here.  sillimanite  appears  "between t h e h o r n b l e n d e - h o r n f e l s  facies  (Turner  contact:  is  fit  i n this  facies.  The f a c t  the g r a n o d i o r i t e s t o c k r u l e s mineral  i s of d e t r i t a l  metemorphic m i n e r a l . corundum with  o f these  of a higher facies,  but the other m i n e r a l s  occurs with  I n both  facies.  trend  itself  the pyroxene h o r n f e l s  i n t h e two a s s e m b l a g e s t h a t corundum o c c u r s  do n o t  only  that  the assemblages l i s t e d  near  this  and i m p l i e s t h a t i t i s a  thermal  above  i n g e n e r a l t h e corundum i s s u r -  muscovite.  These d i s c r e p a n c i e s a r e d i f f i c u l t suggested  Corundum  q u a r t z , sometimes i t i s e v e n i n c o n t a c t  that mineral, although  r o u n d e d by  facies.  assemblages a r e char-  out the p o s s i b i l i t y  origin  Both  t o a s s i g n t o any s i n g l e  o f the h o r n b l e n d e - h o r n f e l s  characteristic  facies,  almandine-amphibolite  two a s s e m b l a g e s a r e g i v e n a b o v e .  f o r corundum t h e m i n e r a l s  acteristic  and  i n some o f t h e r o c k s c l o s e t o t h e  assemblages a r e d i f f i c u l t  Except  facies  1948).  Corundum o c c u r s  these  The l o w e s t  slightly  i s the intermediate or t r a n s i t i o n a l  facies  granitic  that  to resolve.  t h a t t h e corundum f o r m e d m e t a s t a b l y  t o h i g h e r temperatures  blende-hornf els  f a c i e s near  than  those  It i s  and i n d i c a t e s a  i n d i c a t e d by t h e h o r n -  the g r a n o d i o r i t e contact.  R e t r o g r e s s i v e metamorphism h a s o c c u r r e d i n some p a r t s  Figure  47.  ACF d i a g r a m f o r t h e r m a l m e t a m o r p h i c h o r n b l e n d e h o r n f e l s rocks w i t h excess SiOp. Coloured" s e c t i o n s r e p r e s e n t assemblages found i n the area.  65  o f the thin  sections  fresh has  aureole  while  of a n d a l u s i t e  andalusite  while  been r e p l a c e d  generally  i n others  to a l a r g e  sections extent  others  are  a p p e a r t o be  any  ation  granitic  the  Why  the  formation  should  known.  r e l a t i o n s h i p of the  contact.  of muscovite  Quartz Diopside  this  I t i s suggested  completely  that  not alter-  retrograde  p o t a s h metasomatism r e s u l t i n g  from a n d a l u s i t e  Hornfels  Unit  and  corundum.  Assemblages  Quartz-biotite-tremolite.  3.  Quartz-diopside-epidote-calcite-chlorite.  k.  Calcite-diopside-tremelite-quartz-oligoclase.  8.  considered  retrograde  2.  7.  Corundum  T h e r e does  Quartz-tremolite-corundum.  6.  mineral  be  1.  5.  Some  completely  show t h a t  some r o c k s  metamorphism i s b r o u g h t a b o u t by in  reveal  These r i m s a r e  a l t e r e d i s not  spatial  lacking.  by m u s c o v i t e .  shows r i m s o f m u s c o v i t e .  while  to  hornfelses  other  of r e t r o g r e s s i v e o r i g i n . fresh  i t is totally  Quartz-diopside-calcite. Quartz-diopside-biotite-tremolite-muscovite. Quartz-plagioclase-chlorite-diopside. Diopside-quartz-calcite-hornblende-tremolite. These a s s e m b l a g e s f i t t h e h o r n b l e n d e - h o r n f e l s  o f t h e r m a l metamorphism f a i r l y diagram f o r t h i s  It different  Figure  k7  shows t h e  ACF  facies.  i s evident  chemical  well.  facies  that  composition  the  assemblages are  from  those  of  described  entirely above.  66  The  rocks  also  are r i c h  alumina  i n silica,  deficient.  lime  and m a g n e s i a ;  Originally  these  they are  r o c k s were  impure  limestones. Apparent minerals  d i s c r e p a n c i e s due t o t h e p r e s e n c e  o f some  i n t h e a s s e m b l a g e s , w h i c h do n o t f i t t h e f a c i e s ,  an  explanation.  Corundum i s c o n s i d e r e d t o i n d i c a t e  to  development o f a h i g h e r f a c i e s  eloped metastably.  That  and i s t h o u g h t  the presence  a  tendency  t o have  of this mineral  need  dev-  i n these  odd  a s s o c i a t i o n s does n o t f i t any f a c i e s p r e v i o u s l y d e s c r i b e d  has  a l r e a d y been e l a b o r a t e d upon.  blages:;  i t i s thought  f o r the presence  Both these m i n e r a l s  h e d r a l g r a i n s t h a t a p p e a r t o be l a t e r in  the r o c k s .  tion be  O l i g o c l a s e occurs  does n o t f i t f o r t h e f a c i e s  an o r i g i n a l  o c c u r s i n some assem-  t o be o f r e t r o g r e s s i v e o r i g i n .  same e x p l a n a t i o n i s o f f e r e d some a s s e m b l a g e s .  Epidote  of c h l o r i t e i n  o c c u r as s m a l l , than  The  sub-  the other m i n e r a l s  i n some r o c k s :  i t s composi-  and t h e m i n e r a l  i s thought  c o n s t i t u e n t o f the r o c k  r a t h e r than  to  a meta-  morphic m i n e r a l .  In those quartz  listed  addition  t o the assemblages l i s t e d  f o r the andalusite h o r n f e l s u n i t  diopside hornfels unit  members.  i n its pelitic  I t has a l r e a d y been demonstrated  assemblages a l s o  belong  above m o s t o f  occur i n the and q u a r t z - r i c h  t h a t these  i n the h o r n b l e n d e - h o r n f e l s  South o f the s t o c k , beds w i t h  these  pelitic  facies.  assemblages  occur  67  at  least  but  as f a r as f i v e  the true  distance  f i v e hundred f e e t ) . itic  thousand f e e t  to g r a n i t i c  from g r a n i t i c  rocks  i s much l e s s  22 i t i s e v i d e n t  From f i g u r e  outcrops (about  that the gran-  c o n t a c t , which d i p s southward and p a r a l l e l t o the h i l l -  side,  i s c l o s e to t h e ground  surface.  METASOMATISM Although the  tourmaline  granodiorite stock,  genous o r i n t r o d u c e d . all  rocks  tion  i n most o f t h e r o c k s  i ti s notcertain Certainly  i n the area.  of schorlite  occurs  there  whether t h i s  i sschorlite  c l o s e to the contact  occurs  i n some p l a c e s  2 cm. l o n g  i nindividual,  granitic  I t h a s been suggested  of  schorlite  rocks.  elsewhere  that potash i n fact  metasoi t may be  m e t a s o m a t i s m was t h e c a u s e o f t h e r e s t r i c t e d  r e t r o g r e s s i v e metamorphism  around the g r a n o d i o r i t e  that has occurred  amount  i n the area  stock.  TEMPERATURES AND PRESSURES DURING The  up t o  i n the metamorphic  m a t i s m a c c o m p a n i e d r e t r o g r a d e metamorphismj that potash  i n rocks  prismatic crystals  on s e r i c i t i z e d f o l i a t i o n pla,nes  rocks near contacts with  propor-  than  f a r removed ftom i t . West o f H a g g a r t C r e e k f a u l t  i sindi-  i n nearly  T h e r e a p p e a r s t o be a h i g h e r  i n rocks  around  approximate  METAMORPHISM  temperatures and p r e s s u r e  to which  TEMPERATURE  200  Figure  48.  in  400  0  C  ^  600  800  D i a g r a m t o show t h e l i m i t s o f t h e t e m p e r a t u r e and p r e s s u r e r a n g e d u r i n g t h e r m a l metamorphism. The d i a g r a m i n d i c a t e s a t e m p e r a t u r e i n t h e r e g i o n o f 6 0 0 ° C and a d e p t h o f c o v e r o f a b o u t 12 km. a t t h e t i m e o f i n t r u s i o n o f t h e g r a n o d i o r i t e stock.  68  the  r o c k s i n t h e a r e a have b e e n s u b j e c t e d c a n be e s t i m a t e d  f r o m t h e t y p e s and g r a d e s  The the to  stability  greenschist 400°C  about  25  facies  f o r assemblages  ranges  i n temperature  stability facies  Rock p r e s s u r e s r a n g e a stability  rock p r e s s u r e .  belonging to from  an e q u i v a l e n t  field ranges  from  temperatures  which  r a n g e s up t o 5QQ°C  The p r e s e n c e  o f 200°to  horn7°0 C. O  Andalusite  and 20 km. o f  o f s i l l i m a n i t e near the c o n t a c t  stock suggests that  must h a v e b e e n r e a c h e d .  a temperature  Corundum i s s t a b l e  i n excess  of at l e a s t  10  km.  a t temperatures i n  o f 600°C.  These  data l i m i t  the temperature  s t o c k a t the time o f i n t r u s i o n  figure  150°C  o f 15 km. t o  o f 20 km.  o f 300°C" a n d a r o c k p r e s s u r e o f a n e q u i v a l e n t  which  about  f o r the thermal metamorphic  up t o an e q u i v a l e n t  field  the g r a n o d i o r i t e  excess  t h e y show.  km.  blende-hornf els  of  field  and i n r o c k p r e s s u r e from  The  has  o f metamorphism w h i c h  t h e s t o c k was i n t r u d e d  o f the g r a n o d i o r i t e  t o above 600°C.  i s p r o b a b l y about  The d e p t h a t 12 km.  (See  48)  AGE RELATIONS  R e g i o n a l metamorphism i s t h o u g h t folding.  Intrusive  t o have  rocks are l a t e r than t h i s  accompanied  folding  as they  Figure 4 9 *  Peso S i l v e r Mines Gamp l o o k i n g n o r t h . Mote s u r f a c e s t r i p p i n g on number One v e i n i n r i g h t foreground and a d i t to c r o s s c u t near dump i n l e f t foreground.  69.  cut across s t r u c t u r a l T h e r m a l metamorphism trusion,  t r e n d s and a r e e n t i r e l y i s spatially  as i s metasomatism.  i o n a l metamorphism  preceded  related  These f a c t s thermal  The e v i d e n c e i s n o t c l e a r amorphism most  to the g r a n i t i c i n indicate  that  reg-  metamorphism.  as t o w h e t h e r r e g i o n a l met-  a c c o m p a n i e d b o t h P h a s e I and P h a s e I I f o l d i n g .  That  o f i t p r e c e d e d Phase I i s i m p l i e d by t h e p a r a l l e l i s m  bedding  and f o l i a t i o n  bedding.  and m e t a m o r p h i c r e c r y s t a l l i z a t i o n  I t seems l i k e l y  from  a s s o c i a t e d w i t h them, before  this  folding  There  that  along  recrystallization  r e g i o n a l metamorphism  was  complete  occurred.  i s no e v i d e n c e  o c c u r r e d a t any  of  t h e n a t u r e o f t h e Phase I I s t r u c -  t u r e s w h i c h a r e open and w h i c h do n o t have  tism  unfoliated.  time  t o s u g g e s t t h a t p o t a s h metasoma-  other than a f t e r  thermal  metamorphism.  ANTIMONY-SILVER-LEAD VEINS  GENERAL STATEMENT  that  What f o l l o w s i s a d e s c r i p t i o n  o f the m i n e r a l i z a t i o n  occurs i n the a n t i m o n y - s i l v e r - l e a d  v e i n s west of H a g g a r t  Greek f a u l t .  Descriptions  since  cases only scant surface  i n most  o f the v e i n s a r e n e c e s s a r i l y  brief,  information i s available.  70.  Limited  u n d e r g r o u n d work has  most s p e c i m e n s s t u d i e d  fault  are  since  oxidized material  included drifts  are  -  included  the  the  number One,  fourth these  pyrite  may  the Rex  three  and  of p y r i t e ,  and  be  from  and  parts  Two, Of  T h r e e and the  Three v e i n s , o f the  four are  same v e i n  i n the  number One,  arsenopyrite,  relative  v e i n to  another.  east  of  of  the  are  to  similar  limonite  (mostly  them.  and  Three  veins  chalco-  Secondary mingoethite),  malachite  abundance o f m i n e r a l s  while  mineralogy  jamesonite, galena, siderite.  Vein  veins,  system,  Two  anglesite, covellite,  The  been  Rex  very  somewhat d i f f e r e n t  i s structurally unrelated  veins  dumps  work h a s  deposits  Creek  area.  v e i n , has  scorodite, bindheimite,  from one  recent  o f the  t e t r a h e d r i t e i n a gangue o f  e r a l s i n these three  chalcocite.  of Haggart  i n G.S.C. r e p o r t s .  number One,  Two  Mineralization consists  No  west o f H a g g a r t C r e e k f a u l t .  i n m i n e r a l o g y and  from  Descriptions  i n t h e map  Pour v e i n s ,  the  is available.  east  s h i p m e n t s o f o r e h a v e been made f r o m any  occurrences  three  only  veins;  material.  not  these d e p o s i t s .  out  surface  o f the  deposits  No  crop  one  of m i n e r a l  Haggart Creek f a u l t  lode  of o x i d i z e d  only  Descriptions  o f o l d a d i t s and done on  are  b e e n done on  and  i s variable  71  Rex  v e i n m i n e r a l i z a t i o n c o n s i s t s of  galena, t e t r a h e d r i t e , s p h a l e r i t e and siderite.  The  a n g l e s i t e and  NUMBER ONE  jamesonite,  p y r i t e i n a gangue of  secondary m i n e r a l s are l i m o n i t e ,  bindheimite,  covellite.  VEIN  Number One trenches f o r a l e n g t h  v e i n i s exposed on s u r f a c e of 800  underground f o r a l e n g t h the accompanying map.  f e e t and  of 600  The  feet.  i t has  i n bulldozer  been d r i f t e d  For i t s l o c a t i o n  v e i n i s sinuous and  Average s t r i k e of the v e i n i s about N20°E i n the  foot.  south and  N60°E  the d i p i s to the northwest a t angles of 50°  more i n the south and the v e i n f a u l t was but  see  i t s width v a r i e s  from a maximum of about t h i r t y f e e t to l e s s than one  f u r t h e r north;  on  40°  or l e s s i n the n o r t h .  Movement  on  normal, the amount of movement i s not known,  i s thought to have been s m a l l .  p o s t - m i n e r a l i z a t i o n movement, but  There i s some evidence of t h i s has  been s l i g h t .  The v e i n i s a more or l e s s r e g u l a r l y m i n e r a l i z e d of b r e c c i a t e d and  or  zone  f r a c t u r e d h o s t rock, t h a t i s bounded on  s i d e s by w e l l d e f i n e d , more or l e s s p a r a l l e l  both  faults.  M i n e r a l i z a t i o n i s f o r the most p a r t c o n c e n t r a t e d near the w a l l s and  the f o o t w a l l i s g e n e r a l l y favoured i n t h i s  respect.  M i n e r a l i z a t i o n i s g e n e r a l l y more massive i n t h i c k s e c t i o n s the v e i n . i s seen.  Replacement along the w a l l s has  of  been s l i g h t where i t  In most cases the only r e c o g n i z a b l e  a l t e r a t i o n of  72  the  wall  rock  i s silicification.  w a l l s by p y r i t e average  i s noticeable.  Some i m p r e g n a t i o n o f t h e The d r i f t  o f a b o u t a h u n d r e d f e e t o f b a c k s and a t t h i s l e v e l t h e  vein i s strongly oxidized locally, secondary minerals  the o n l y  arsenopyrite, up  on t h e s u r f a c e h a s b e e n  primary m e t a l l i c constituents pyrite  and j a m e s o n i t e .  more t h a n e i g h t y p e r c e n t  face.  a l t h o u g h f o r t h e most  part  are absent.  Secondary a l t e r a t i o n and  on t h e v e i n h a s a n  I t i s thought  with  bindheimite.  site  and b i n d h e i m i t e  that  intense  recognizable  are  Secondary minerals  make  o f the m i n e r a l i z a t i o n a t the sur-  silver  a t the s u r f a c e  Lead a t the s u r f a c e  i s associated  i s represented  and t h e a n t i m o n y v a l u e s  by  angle-  are a l l h e l d i n  bindheimite.  Movement plored  parts  (5.2: 1) or l e s s  constant.  trenches, pyrite  o f t h e number One v e i n .  and s i l v e r  been m o b i l e .  o f m e t a l s h a s n o t been e x t e n s i v e Silver  to l e a d  t o l e a d and a n t i m o n y r a t i o s Copper i s the only metal  there  i s a considerable  some p a r t s  covellite,  o f the d r i f t  gene e n r i c h m e n t  suggests  proportion  i n copper a t t h i s  i n surface of chalcoThe  pre-  c h a l c o c i t e and m a l a c h i t e that  there  level.  a r e more  t h a t has d e f i n i t e l y  i n the m i n e r a l i z a t i o n exposed i n the d r i f t .  sence o f c o n s i d e r a b l e  ratios  (3»3* 1)  No c o p p e r m i n e r a l i z a t i o n i s e v i d e n t  while  i n t h e ex-  h a s b e e n some  in super-  Figure  50.  P y r i t e (Py) and a r s e n o p y r i t e (Apy) s h o w i n g e u h c d r a l h a b i t e n c l o s e d by a n h e d r a l p y r i t e . 1-Nicol. x 25.  Figure  51.  Two h a b i t s o f p y r i t e (Py) e u h e d r a l g r a i n s and a g g r e g a t e s o f a n h e d r a l g r a i n s . Siderite (s) shows same r e p l a c e m e n t t e x t u r e s t o b o t h pyrite habits. N o t e ' l a y e r i n g i n the aggregate of anhedral b y r i t e . 1-Nicol. x 66. 1  73.  Number One  vein contains  the  following  primary  minerals: Pyrite  48$  Arsenopyrite  15$  Jamesonite  15$  Chalcopyrite  10$  Siderite  10$  Tetrahedrite  It  i s estimated  between o n e - f o u r t h  and  2$  that hydrothermal minerals  one-half  of  the  volume o f the  make  up  entire  vein.  Textures  The o f number One  textures  e x h i b i t e d by  vein  described  Pyrite common h a b i t less  soidal  and  i s as  .05  than  are  mm.  across.  i n shape and  many c a s e s .  for  replacement  habits. pyrite  No and  number One  one  fine,  section.  habits.  anhedral,  across.  also  The  most  equant  often  grains  ellip-  I t i s thought  of l a t e r minerals  suggesting  arsenopyrite vein contains  the  that  are  the  as  these  emplacement  sequence  have been noted. traces  in  o c c u r l e s s commonly  a n o t h e r c l o s e l y i n the  textures  textures  show two  Such aggregates are  Both these m i n e r a l s  followed  following  minerals  show a l a y e r i n g o r b a n d i n g o f g r a i n s  e u h e d r a l c r y s t a l s .2 mm. habits  hydrothermal  i n the  arsenopyrite  aggregates of  the  sequence,  same f o r b o t h  of d e p o s i t i o n  Arsenopyrite  o f a n t i m o n y and  two  from  manganese.  of  Figure  52.  M a s s i v e .jamesonite s h o w i n g p a r a l l e l i n t e r g r o w t h o f c o a r s e p r i s m a t i c g r a i n s and d r a g n o s t i c b a s a l cleavage along which secondary alteration is localized. X-Nicols. x 25.  74.  Jamesonite  is definitely  later  than p y r i t e  for i t  sometimes o c c u r s i n v e i n l e t s w h i c h c u t t h a t m i n e r a l . One  vein  jamesonite  parallel  crystals  5 mm*  Jamesonite  of s i m i l a r  type  of jamesonite  jamesonite.  No  evidence  second  interpretation  veined  and  no  considered  can  X-ray  the f o u r v e i n s has accompanying jamesonites  table. are  the v a r i a t i o n  is  be  intergrown,  scattered,  commonly acicular  in siderite.  c o n s i d e r e d as e i t h e r interpreted  The  late  of i t are found.  as r e m o b i l i z e d but  jamesonite Late  This  newly  f o r e i t h e r e x p l a n a t i o n i s seen,  i s preferred.  the  i s un-  jamesonite  is  introduced mineral.  powder p h o t o g r a p h b e e n made and ( T a b l e 1)  of jamesonite  the r e s u l t s  from  each  i n d spacings i s not  table.  of  are g i v e n i n the  Spectrographic analyses of  incorporated i n this  these  I t i s evident  apparently systematic  c o r r e l a t i o n b e t w e e n m i n o r c o n s t i t u e n t s and  d  that  and  spacings  obvious.  Chalcopyrite The  o c c u r s as  o r i t c a n be  replacements  the f i n a l  An  also  of  G r a i n l e n g t h s are  l e n g t h , randomly o r i e n t e d  introduced with s i d e r i t e ,  t h a t no  aggregates  oriented, prismatic grains.  a s much a s  second  o c c u r s as m a s s i v e  I n number  i s apparently l a t e r  than  jamesonite.  m i n e r a l o c c u r s i n a n h e d r a l , i r r e g u l a r m a s s e s commonly 1  o r so a c r o s s i n s i d e r i t e sonite  appears  alization  or jamesonite.  cleavage  to have e x e r t e d c o n s i d e r a b l e c o n t r o l  of chalcopyrite,  of c h a l c o p y r i t e  The  f o r examples o f l a t h s  i n jamesonite  are  plentiful.  of  mm.  jame-  on t h e  loc-  or "peninsulas*  TABLE 1 Jamesonite ( 4 P b S . PeS. 3 S D 2 S 5 ) (from each o f the f o u r v e i n s a t S e c r e t d(obs)  d(obs)  d(obs)  I  No.l  No.2  No.3  Rex  1/2  6.00  6.15  6.03  6.10  6.03  (220)  1/2  5.01  5.04  5.09  5.09  5.10  (310)  7  4.06  4.11  4.10  4.14  4.10  (240)  8  3.81  3.87  3.87  3.91  3-87  (400)  10  3.42  3.44  3.46  3.46  3.44  7  3.09  3.09  3.11  3.09  1  2.93  2.96  2.98  2.98  2.95  (260)  6  2.82  2.84  2.84  2.84  2.84  (411)(33D  8  2.71  2.74  2.72  2.75  2.75  (4H)(450)  2  . .2,29  2.29  2.29  2.31  2.30  2  2.23  2.24  2.24  2.25  2.24  (6402 (470K171) (560)(171)  1/2  2.16  2.19  2.16  2.17  2.16  (380)(271)  2  2.05  2.07  2.06  2.06  2.06  5  2.03  2.03  2.02  2.02  2.02  1/2  1.961  1.969  1.965  1  1.904  1.914  1.907  1/2  1.860  1.873  1.866  2  1.828  1.836  1.831  1/2  1.716  1.725  1.725  Ag Cu Sn As Bi  3.09  Ag Cu Sn As Bi  Bi As Ag Cu Sn  d(obs)  Greek)  Ag Sn Cu Zn  d(obs) tierry & Thompson  (hkl)  (2502  (23D(321) (350)(510)  (740)(660)  Trace c o n s t i t u e n from Spectrograpl Analyses. ( i n dc c r e a s i n g o r d e r oj abundance) -  75  Siderite, introduced and  t h e gangue m i n e r a l ,  i n two s t a g e s .  brownish yellow  finer  grained  mobilized  Early  i n colour,  i s coarse  and o c c a s i o n a l l y h a s r e -  been f i l l e d  emplacement a r e  o f b r e c c i a t i o n , p r o b a b l y due t o m i n o r  except l a t e jamesonite  fault.  A l l the m i n e r a l s mentioned  are b r e c c i a t e d  with l a t e s i d e r i t e .  and t h e f r a c t u r e s  Early  siderite  and  the a n g u l a r i t y  the  initial  remobilized  during  of late siderite  Whether the second  cutting early  siderite  o r newly i n t r o d u c e d  siderite  theory i s favoured.  the e a r l y stage  was  side-  remobilized  i s n o t known, b u t  The mechanism t h a t i n -  i s considered of s i d e r i t e  second b r e c c i a t i o n o f the v e i n fractured  that  generated  or i n -  t h e s e c o n d s t a g e .of b r e c c i a t i o n o f t h e v e i n .  Tetrahedrite during  breccia  small.  d u c e d r e m o b i l i z a t i o n may h a v e b e e n t h e h e a t troduced  slight.  i n the vein  on t h e v e i n was a l s o  A few i n s t a n c e s  siderite  fractures  bound-  and s i z e o f t h i s v e i n b r e c c i a i n d i c a t e s  movement  are found.  fills  have  I n some c a s e s m a t c h i n g  a r e s e e n , i n d i c a t i n g t h a t movement was o n l y  early  grained  the l a t e s i d e r i t e i s  two d i f f e r e n t s t a g e s o f s i d e r i t e  renewed movement on t h e v e i n  the  while  and l i g h t e r c o l o u r e d  s e p a r a t e d by a p e r i o d  rite  siderite  been  ? jamesonite i n i t .  The  aries  a p p e a r s t o have  t o have been  emplaced  i n t r o d u c t i o n and b e f o r e  occurred.  and v e i n e d w i t h l a t e s i d e r i t e .  This mineral  i s often  No t e x t u r a l r e l a t i o n -  76  ships  between t e t r a h e d r i t e and  because  t e t r a h e d r i t e always occurs  brecciated  grains  grains  commonly 1 cm.  are  o r more a c r o s s ;  An  indicates  edge o f  a high  s i l v e r content  a late  typical  stage  of alpha  Quartz c r y s t a l s  quartz occur  tetrahedrite  s p a r i n g l y i n the  and  only  are  brecciated  .1  mm.  is  Number  consid-  (10.37  and  mineral.  v e i n and  is  considered  C r y s t a l s show the  commonly one  in late  Such  of t e t r a h e d r i t e from  f o r the  gangue m i n e r a l .  individual  This value  seen,  equant,  in siderite.  a minimum o f  10.58(8)^.  than that of o r d i n a r y  Quartz occurs t o be  reach  X - r a y powder p h o t o g r a p h  v e i n gave a c e l l  erably higher  and  are  as l a r g e , a n h e d r a l ,  or aggregates of grains  f r a g m e n t s a r e much s m a l l e r  One  other m e t a l l i c minerals  o r two  habit  cm.  long.  siderite.  Secondary A l t e r a t i o n  Secondary a l t e r a t i o n tensive.  Minerals  are  below w i t h  given  i n number One  t h a t h a v e d e v e l o p e d a t and their  relative  near the  been  35$  Anglesite  15$  Bindheimite  30$  Scorodite  12$  Covellite  1$  Chalcocite  5$) ) Found o n l y 1$)  ex-  surface  proportions:  Goethite  Malachite  v e i n has  underground  F i g u r e 53.  Goetfrite a l t e r a t i o n c o n t r o l l e d by rhomboh e d r a l c l e a v a g e of s i d e r i t e r e s u l t i n g i n open boxworks. l - M c o l . x 2 5 .  77.  These ation minerals vein.  No  secondary of the  assemblage  are  of primary minerals  i s generally controlled  primary m i n e r a l s .  controlled  by  the  Jamesonite  the c l e a v a g e  cleavage  i n that mineral.  i n that mineral.  of  the  the s t r u c t u r e  G-oethite i s i n  lines  tetrahedrite  and m i m e t i c brecciation  and  fractures  as p a l e , l e e k g r e e n ,  or cleavage.  e a r t h y masses t h a t are  occurs  sometimes s t a i n e d analysis  o f s c o r o d i t e gave As  and  Ee  traces  Cu,  Zn, A l i n d e c r e a s i n g o r d e r o f  o f Sb,Pb, Ag,  cracks  con-  mineral  A spectrographic  to g o e t h i t e admixtures. as  The  after  chalcopyrite.  f o r m s embayments i n a r s e n o p y r i t e t h a t a r e n o t  t r o l l e d m a r k e d l y by  brown due  by  siderite  Covellite  the p r i m a r y m i n e r a l s , m a i n l y  Scorodite  alter-  alteration i s strongly  boxworks t h a t a r e pseudomorphous a f t e r  in  characteristic  j a r o s i t e s h a v e b e e n r e c o g n i z e d so f a r .  Alteration o f the  minerals  the major c o n s t i t u e n t s w i t h abun-  dance .  Chalcocite pyrite  g r a i n s and  number One  forms  soft,  i s found  black, sooty coatings  o n l y u n d e r g r o u n d i n the  on  drift  on  vein.  Paragenesis  The secondary  paragenetic  minerals  of t e x t u r e s .  A Van  sequence o f the h y d r o t h e r m a l  i s clear  from  and  the f o r e g o i n g d e s c r i p t i o n s  de V e e r d i a g r a m  showing  the p a r a g e n e s i s  is  F i g u r e 54»  V a n de V e e r d i a g r a m t o show p a r a g e n e s i s o f p r i m a r y a n d s e c o n d a r y m i n e r a l s o f number One vein.  N U M B E R v a n de  veer  ONE  VEIN  par a g e n e t i c  diagram  78  included  i n f i g u r e 5^.  portions  o f the hydrothermally  Temperature  This  of Deposition  diagram  is  given  at 573°C  quartz,  data.  by t h e p r e s e n c e  a s i m i l a r maximum.  rite,  282°C, g i v e s  arsenopyrite of d e p o s i t i o n obtained  of deposition  of alpha  quartz,  point  since  faith  The  of that mineral.  deposit,  to obtain  arsenopyrite  hypothermal c o n d i t i o n s  a temperature  of  so t h a t  obtained.)  as a mesothermal c a v i t y rock.  filling  The e a r l y  and p y r i t e , i n d i c a t e a t e n d e n c y a t the beginning  The  below 300°C was  recently,  i n the temperature  i s classified  of side-  (The c o r r e c t n e s s  formed a f t e r b r e c c i a t i o n o f the h o s t  minerals,  6lO°C,  of that mineral.  A temperature  o f (203)=1.6304.  c a n be p l a c e d  vein  which i n v e r t s t o beta  above w h i c h t h e v e i n  emplacement  t h i s geothermometer h a s been q u e s t i o n e d little  of deposition  The d i s s o c i a t i o n t e m p e r a t u r e  g e o t h e r m o m e t e r was employed  from a s p a c i n g  minerals.  c a n be e s t a b l i s h e d  o f jamesonite,  a maximum t e m p e r a t u r e  cannot have been h e a t e d  and secondary  A maximum t e m p e r a t u r e  The m e l t i n g  gives  introduced  pro-  and C l a s s i f i c a t i o n  Wo good t e m p e r a t u r e f o r geothermometric  a l s o shows r e l a t i v e  toward  of the d e p o s i t i o n a l  period.  NUMBER TWO  VEIN  Number Two v e i n l i e s  northeast  o f number One v e i n .  Figure  55.  A n h e d r a l g r a i n s o f a r s e n o p y r i t e (Apy) enclosed by c o a r s e g r a i n e d p a r a l l e l i n t e r g r o w t h s o f "Jamesonite* I n c i p i e n t secondary a l t e r a t i o n s along g r a i n boundaries i s evident* 1-Nicol. x 25.  79.  The  a t t i t u d e and w i d t h o f the v e i n  One v e i n . its  The s t r i k e  o f number Two v e i n  are considered  t h a t number Two v e i n may vein. vein  and t h e o n l y  in  be t h e o f f s e t  the v e i n a t v a r i o u s similar  of minerals vary  minerals.  extension  o f number One  h a s b e e n done on t h e  intervals.  bulldozer Number Two  vein  t o number One v e i n , h o w e v e r p r o p o r -  as i s e v i d e n t  The p r i m a r y m i n e r a l s  the f o l l o w i n g  Number One a n d number  i n f o r m a t i o n , a v a i l a b l e i s from  is mineralogically  o f number  o f one s y s t e m and i t i s t h o u g h t  No u n d e r g r o u n d work o r d r i l l i n g  trenches across  tions  part  to that  i s a b o u t N70°E and  5 ° ° "to t h e n o r t h w e s t .  d i p i s roughly  Two v e i n s  i s similar  from  the l i s t s  i n number Two  of primary  v e i n are  present  proportions:  Arsenopyrite  30$  Jamesonite  63$  Pyrite  5$  Chalcopyrite  1$  Siderite  1$  Textures  The is  strongly  obliterated to g i v e test tures  material  oxidized. by t h i s  an a c c u r a t e  f r o m number Two v e i n Primary  alteration  textures  t h a t was  a r e o f t e n masked o r  and i t i s t h e r e f o r e  d e s c r i p t i o n o f them t h a t  o f t i m e as t h e v e i n i s e x p l o r e d t h a t are seen are i d e n t i c a l  studied  further.  will  difficult stand  Primary  the tex-  t o t h o s e o f number One  vein.  Figure  56.  V a n de V e e r d i a g r a m t o show p a r a g e n e s i s o f p r i m a r y and s e c o n d a r y m i n e r a l s o f number Two vein.  80.  Secondary A l t e r a t i o n  The in  order  secondary minerals  i n number Two v e i n a r e g i v e n  o f abundance and w i t h r e l a t i v e  following  percentages i n the  table. Scorolite  50$  Anglesite  25$  Bindheimite  20$ 5$  Goethite  Textures e x h i b i t e d same a s t h o s e  described  by t h e s e c o n d a r y m i n e r a l s  f o r number One  are the  vein.  Paragenesis A Van de V e e r d i a g r a m 56.  figure not  The d i a g r a m i s b a s e d  as t r u s t w o r t h y  Temperature  of Deposition  The similar  as t h a t  temperature  to that  given  f o r number Two v e i n on s c a n t  of deposition  ature  the temperature  i n number Two v e i n  The a r s e n o p y r i t e  deposition  vein.  i s considered  but the r e l a t i v e  over minerals  vein.  and i s  and C l a s s i f i c a t i o n  ance o f a r s e n o p y r i t e  somewhat h i g h e r  information  f o r number One  o f number One v e i n ,  indicates that  i s given i n  suggestive  t o be predomin-  of lower  temper-  o f d e p o s i t i o n was  perhaps  t h a n i t was i n number  One  g e o t h e r m o m e t e r gave a t e m p e r a t u r e o f  f o r that mineral  Number Two v e i n  b e l o w 350°C.  i s classified  a s a m e s o t h e r m a l to"  81.  hypothermal  cavity  filling  type v e i n  deposit.  NUMBER THREE VEIN  Number T h r e e v e i n i s a l o n g s t r u c t u r e , relatively ized  little  shoots that  along,  i s known.  t o be c o n t r o l l e d  f e e t , b u t no u n d e r g r o u n d  done on i t . angle and  I t strikes  o f about  fault  pyrite  50°•  breccia  Branching ization  work o r d r i l l i n g h a s b e e n  that  i s sparingly  Lenses  impregnated  of siderite  containing  but these are g e n e r a l l y  of mineralized  structures  found c l o s e  l e n s e s a r e much  are thought  up l e s s  average  gouge  arseno-  jamesonite strongly one  hundred  the m i n e r a l -  t o t h e s h e a r zone i n some c a s e s .  estimated r e l a t i v e  t h a n 10$ o f t h e e n t i r e  exposed  Galena  35$  Jamesonite  45$  Siderite  15$  Pyrite  a t an  smaller.  t o have l o c a l i z e d  P r i m a r y m i n e r a l s i n number T h r e e with t h e i r  with  W i d t h s o f t h e s h e a r zone v a r y t o a l m o s t  but widths  thirteen  a b o u t N 8 0 ° E and d i p s n o r t h w a r d  and g a l e n a o c c u r l o c a l l y ,  feet,  f o r at least  The  The s h e a r zone c o n t a i n s s i l i c i f i e d  and p y r i t e .  oxidized.  by, b u t n o t a l l  t r e n d i n g zone o f s h e a r i n g .  s t r u c t u r e h a s b e e n f o l l o w e d on s u r f a c e thousand  which  The v e i n i s made up o f m i n e r a l -  a r e thought  one m a i n , e a s t w a r d  about  5$  v e i n are l i s t e d  proportions. vein.  below  They make  Figure  57«  Discontinuous s t r i n g e r s of anhedral g r a i n s ( d a r k ) i n galenaT" 1-Nicol. x 25.  pyrite  82  Textures  Mineralized little  pyrite  and  l e n s e s from  arsenopyrite.  t h a t have been i d e n t i f i e d galena,  jamesonite  Pyrite layers  and  jamesonite  and  sparingly  subhedral,  minerals  number T h r e e v e i n a r e  discontinuous stringers  or  equant g r a i n s i n g a l e n a ,  In s i d e r i t e ,  of anhedral  as a n h e d r a l  only other primary  siderite.  siderite.  blebs or aggregates  The  i n m a t e r i a l from  occuts i n thin,  of i n d i v i d u a l ,  number T h r e e v e i n c o n t a i n v e r y  pyrite  grains.  also  occurs  Arsenopyrite  grains i n siderite,  but not  as  occurs  i n the  other  minerals.  Galena coarse up  of both  galena in  grain  i n number T h r e e v e i n i s i n m a s s e s o f  size  i n a gangue o f s i d e r i t e .  'strained'  i s e v i d e n t from  the m i n e r a l , w h i l e  surfaces.  The  e g u l a r and  apparently  the way  the  two  and  Sn  the  types  S u c h masses a r e made  'unstrained' galena.  the bent  nature  o f the  from  'Strained' cleavage  ' u n s t r a i n e d ' v a r i e t y has of galena  are i n t e r g r o w n  random f a s h i o n t h a t may  s p e c i m e n was  Galena Cu  and  relatively  surfaces  flat i n an  s i m p l y be  cleavage irrdue  to  cut.  number T h r e e v e i n c o n t a i n s A s ,  Sb,  Ag,  i n d e c r e a s i n g o r d e r o f abundance t r a c e c o n s t i t u e n t s .  Jamesonite between j a m e s o n i t e  occurs  and  separately i n siderite.  g a l e n a were n o t e d .  Jamesonite  Wo  contacts  is in  Figure 5 8 .  Van de Veer diagram to show paragenesis of primary and secondary minerals of number Three vein.  NUM B E R v a n de v e e r  THREE  VEIN  pa r a g e n e t i c  diagram  83.  blebs  and  masses o f  'veinlets'  f i n e , matted,  of coarse grained  arrangements of g r a i n s , type of  texture  assayed  and  erals,  but  that  is  i n the  found  show a  such banding the  cuts  case  66  oz.  g a l e n a and  of  texture  Wo  of  silver  This  vein.  been  per  for included  ton.  The  silver  min-  jamesonite.  jamesonite.  due  Where  siderite  c o n t r o l l e d by  the  such cleavage c o n t r o l of  to c o l o u r  occurs i t i s p a r a l l e l  galena or  mats.  noted.  that mineral.  'flow'  s h o w i n g random  f o u n d i n Rex  g a l e n a i t s emplacement i s g e n e r a l l y of  also  Sinuous  number T h r e e v e i n has  as much as  none were  cleavage  i.e.  the  grains.  such f i n e g r a i n e d  been c a r e f u l l y s t u d i e d  Siderite cuts  traverse  from  contains  j a m e s o n i t e has  jamesonite,  i s s i m i l a r to  Jamesonite  prismatic  jamesonite. -  Veinlets  siderite  of s i d e r i t e  banding of carbonate. to the  walls  siderite  of  often Where  the  veinlets  and  gangue  contacts.  Secondary A l t e r a t i o n  Extensive  oxidation  o f number T h r e e v e i n has anglesite, to t h a t  bindheimite  described  of  primary sulphides  r e s u l t e d i n the  and  scorodite.  f o r number One  formation  The  of  goethite,  alteration is similar  vein.  Paragenesis  The simple.  A Van  paragenesis de  o f number T h r e e v e i n m a t e r i a l  V e e r diagram  to  show the  paragenetic  is  rather  sequence  84  is  included  is  scant,  i n f i g u r e 58... S i n c e  this  The  p a r a g e n e s i s may  'flow  1  texture  that perhaps c o l l o i d a l stage.  Colloidal  The  the m a t e r i a l  be  textures  incomplete.  exhibited  deposition  by s i d e r i t e  was i n v o l v e d  are also  combination  •unstrained'  galena i n intimate  intergrowths  v e i n as w e l l  as t h e f r a c t u r e d n a t u r e  indicate that  s t r u c t u r e has occurred brecciation osited  suggests  during  this  f o u n d i n Rex v e i n  seemingly strange  siderite)  a v a i l a b l e t o date  o f ' s t r a i n e d ' and i n number  of galena  some movement  material.  Three  (later f i l l e d  on t h e number T h r e e  after deposition  of galena.  of jamesonite i n d i c a t e s that  by  vein  The l a c k o f  this mineral  was  dep-  a f t e r t h i s movement h a d c e a s e d .  Temperature  of Deposition  The jamesonite  relative  and C l a s s i f i c a t i o n  predominance o f m i n e r a l s  o v e r p y r i t e i n number T h r e e v e i n  like  g a l e n a and  i n contrast  to the  opposite  r e l a t i o n s h i p i n number One and number Two  veins,  suggests  t h a t m i n e r a l i z a t i o n was  temperatures  in  number T h r e e v e i n  veins. cketed the  Conditions  emplaced  t h a n i t was  at lower  i n number One and number  o f temperature  and p r e s s u r e  Two  c a n n o t be b r a -  more c l o s e l y t h a n h a s b e e n done f o r number One v e i n and  temperature  range g i v e n  f o r number T h r e e v e i n by  thermometers i s s i m i l a r to t h a t  The vein deposit  vein  i s classified  o f number One  vein.  as a n open f r a c t u r e  formed under mesothermal  geologic  conditions.  filling,  85.  REX  VEIN  Extensive this  structure  mineralized  at  the  amount o f  uity  the  fifty the  about a  but  55°»  clayey  The  the  fault  fault  vein  at angles  recently  on  was  on  the  has  The the  The  The  part  of  three  vein  is A  contin-  hundred  been s t a r t e d  and  to  explore  only  fault  vein  but  .  veins  des-  i s an  Mineralization  northward  at  l a r g e l y normal  with  vein  i s composed o f  known,  fine  number One  vein  fault  on  where  fragments.  i n v a r i a b l y plunge  to the  east  P o s t m i n e r a l i z a t i o n movement, i f  the  the  dips  angular breccia  walls  of  was  the  amount o f movement i s n o t  l a r g e r t h a n on  foot wall  of  i t i s t h o u g h t t h a t movement  been s l i g h t .  east,  fault  the  this basis  from about twenty f e e t a t west end.  vein  component.  s t e e p e r t h a n 80  occurred,  gouge.  exposed  The  t e s t the  s t r i k e s N 8 0 ° E and the  zone c o n t a i n s  Slickensides  to  b e e n done t o  t o a maximum d e p t h o f  Movement on  gouge and  vein  ially  thousand f e e t .  i s l e s s s i n u o u s t h a n any  unmineralized  the  it  d r i l l i n g has  vein  dextral  the  two  v e i n has  over about h a l f of i t s l e n g t h .  a p r o g r a m has  before.  small  of  Rex  underground.  Rex cribed  surface  structure  f e e t , and  vein  s t r i p p i n g on  f o r a length  limited of  surface  The  vein  eastern  the  vein  zone v a r i e s  end  to f i v e  i s well  hanging wall  feet  defined,  i s not  as  i r r e g u l a r l y mineralized  t e n d s t o be  i n width at  the  espec-  prominent.  zone o f  concentrated near  the  fault  8 6  hanging wall in and  a t t h e w e s t end o f t h e v e i n and on t h e f o o t  the e a s t e r n  part.  M i n e r a l i z a t i o n i s m a s s i v e where  i s i n discontinuous,  parallel gouge.  to the v e i n w a l l s  tion.  pre-ore  on t h e b a s i s  and t e n d  intersection with  volume  o f Rex v e i n  average  relative  fault  to plunge  of l i m i t e d d r i l l i n g  steeply  informa-  t h a t meet t h e m a i n s t r u c t u r e a r e  to concentrate  the main  Primary minerals  that are  and w h i c h a r e s u r r o u n d e d by  Minor branching f a u l t s  apparently  i t occurs  and b r a n c h i n g pods  Pods o f m i n e r a l i z a t i o n a r e c o n s i d e r e d  eastward i n the v e i n  their  lenticular  wall  mineralization  near  structure.  make up l e s s t h a n one h a l f o f t h e  and a r e l i s t e d  below w i t h  their  estimated  proportions.  Siderite  35$  Jamesonite  25$  Dolomite  15$  Galena  7$  Boulangerite  5$  Tetrahedrite  5$  Sphalerite  5$  Pyrite  3$  Textures  Textures Rex v e i n  shown by t h e h y d r o t h e r m a l m i n e r a l s  a r e more c o m p l e x t h a n a r e t h o s e e x h i b i t e d by  i n the these  Figure  59•  G r a i n o f s p h a l e r i t e s u r r o u n d e d by .jamesonite and e n c l o s i n g l a t h s o f 1-Nicol. x 25.  massive jamesonite  Figure  60.  F r a c t u r e i n t e t r a h e d r i t e ( t ) f i l l e d by s i d e r i t e (s). Tetrahedrite encloses l a t h s of jamesonite. X-Nicols. x 75.  87  minerals  i n the  other veins.  A r s e n o p y r i t e has pyrite  occurs  dolomite, erite.  i n euhedral  siderite  The  number One  found  galena  dolomite,  v e i n i s not noted  occurs  open s p a c e  siderite  suggest  enitic  sequence.  and  the handspecimen. Rex  the  in  cell  to  substitution  excess  Two  (002)  edge f r o m  o f 40$  commonly g a l e n a .  of i r o n  was  it  A b o u t 6$  i s suggested  sphalerite zinc.  i s due  mineral by  to s u b s t i t u t i o n  in  of  i n the  this  parag-  sphalerite  5.42(6)$. I f the  variation  i s due  a mole p e r c e n t a g e  (Det-  entirely  o f FeS  T h i s seems e n t i r e l y u n l i k e l y  remainder  from  The  r e d d i s h brown i n c o l o u r  o f 5*409 f o r p u r e ZnS  FeS.-is e s t i m a t e d  I t i s estimated  in  sphal-  encrusted  formed e a r l y  dark  but  vein.  ways.  reflections)  for zinc,  t h a t the  Rex  powder p h o t o g r a p h s o f  (004)  i s indicated.  and  Textures  edges o f 5 . 4 4 ( 0 ) $ and  a value  side,  g r a i n s or g r a i n aggregates  X-ray  and  vein,  i n a s s o c i a t i o n s from  v e i n i n two  the b a s i s o f the c o l o u r o f the m i n e r a l analyses.  on t h e  on w a l l r o c k  is typically  v e i n gave c e l l  e r m i n e d from  seen  filling  less  t o 5 mm.  commonly i n g a l e n a  i n Rex  that sphalerite  The m i n e r a l  from  up  i n t h e Rex  i n m a t e r i a l from  as e q u a n t , c o r r o d e d  nature  in  cubes,  other h a b i t of p y r i t e  as an  and  been noted  and much l e s s  Sphalerite is  not  and  from  from these  of v a r i a t i o n  in on  spectrographic two  sources  in cell  edge  and of  o f cadmium and manganese f o r  d a t a by S k i n n e r  (1961) t h a t  less  Figure  61.  J a m e s o n i t e (.j) and t e t r a h e d r i t e ( t ) i n c o n t a c t . N o t e v e i n l e t o f .jamesonite i n t e t r a h e d r i t e . X-Nicols. x 25.  Figure  62.  J a m e s o n i t e l a t h s ( j ) e n c l o s e d by s i d e r i t e showing t r i a n g u l a r cleavage p i t s . 1-Nicol. x 75.  (s)  88.  than  two  mole p e r c e n t CdS  the v a r i a t i o n  A  in cell  would account  edge o f s p h a l e r i t e  spectrographic analysis  f o r the remainder from  o f Rex  i t s normal  value.  vein sphalerite  the f o l l o w i n g m i n o r c o n s t i t u e n t s i n d e c r e a s i n g o r d e r o f dance:  Cd,  Sb,  Ag,  Cu,  Tetrahedrite with corroded mineral  hedrite  and  Pb,  occurs  boundaries  i s c u t by  dolomite  Mn,  i n large,  which are l i n e d w i t h  this mineral  equant g r a i n s  jamesonite.  The  that are f i l l e d  supergene c o v e l l i t e .  t o have e x s o l v e d f r o m  of tetraliedrite  formed r e l a t i v e l y  l a c k of t e x t u r a l  with  Tetra-  early  i t seems f a i r l y i n the h i s t o r y  it.  deposited f i r s t .  Grains  to say which o f these of t e t r a h e d r i t e  of  Prom  certain  that  o f the v e i n ^  r e l a t i o n s h i p s between t e t r a h e d r i t e  s p h a l e r i t e makes i t d i f f i c u l t  imeter  abun-  o f t e n c o n t a i n s s m a l l , equant, randomly o r i e n t e d b l e b s  the c o r r o d e d n a t u r e  was  and  roughly  narrow f r a c t u r e s  c h a l c o p y r i t e , which i s thought  The  shows  Sn.  in siderite  straight,  of  and  two  minerals  a r e commonly a  cent-  o r more a c r o s s .  An gave a c e l l Pe  X-ray  powder p h o t o g r a p h  edge o f 1 0 . 5 7 ( 6 ) $ and  Pb  and  with  t r a c e s o f Sn,  of  abundance, i s i n d i c a t e d  Galena t u r n e n c r u s t e d by needles)  and  occurs  as  dolomite  Zn,  o f Rex  vein  the p r e s e n c e Cd,  A s , Au,  tetrahedrite  o f Sb,  i n decreasing  i n a spectrographic  Ag, order  analysis.  encrustations of sphalerite (which  Cu,  and  is in  often encloses boulangerite  t h e w h o l e a s s o c i a t i o n i s c u t by  siderite.  A  few  Figure  63.  P i n e g r a i n e d .jamesonite ( j ) ' c u t ' by a s t r i n g e r o f c o a r s e g r a i n e d j a m e s o n i t e (j)» Note t h e trachytoid l i k e t e x t u r e and i n c i p i e n t a l t e r a t i o n a l o n g c r a c k s n o t c o n t r o l l e d by c l e a v a g e of jamesonite. X-Mcols. x 25. 1  Figure  64.  1  J a m e s o n i t e ( j ) and g a l e n a ( g ) i n c o n t a c t , s h o w i n g the a p p a r e n t r e p l a c e m e n t o f g a l e n a by j a m e s o n i t e t h a t i s i n no way c o n t r o l l e d by t h e c l e a v a g e o f g a l e n a . 1 - N i c o l . x 25.  89  pyrite  c u b e s were o b s e r v e d  Galena  i s g e n e r a l l y c o a r s e g r a i n e d and  few be  entirely  specimens o f g a l e n a w i t h s l i g h t l y found.  Textural  relationships  suggest  that  ded  corroded that mineral.  and  jamesonite  Galena Cu,  Sn  from  is later  Rex  grown a g g r e g a t e s  bent  cleavage planes  between g a l e n a and than galena  since  contains traces  of thick,  Jamesonite  'trachytoid'  slightly  prismatic  texture.  jamesonite.  usually  prisms  i t has  o f Sb,  inva-  Ag,  Zn,  grains,  and  number giving  'cut' t h i s  by  grained jamesonite.  dolomite  i s evident."  cases are g e n e r a l l y and  dolomite  are  prisms  removed s l i g h t l y  surrounded  of jamesonite  jamesonite  Individual  by  from  dolomite.  i s also  of  often protrude into  the i n such  jamesonite  e v i d e n t i n such cases. and  to  is  agg-  Extensive invasion  i s i n contact with tetrahedrite  of jamesonite  of  parallel  of jamesonite the  banded  two m i n e r a l s a r e  s e e n i n c o n t a c t a c o n s i d e r a b l e amount o f d i s r u p t i o n jamesonite  Two  finer grained  Jamesonite  and where t h e s e  than  a  I n many s p e c i m e n s n a r r o w b a n d s  has  inter-  commonly l e s s  S u c h n a r r o w bands a r e g e n e r a l l y  o f the f i n e  surrounded  tetrahedrite  a r e commonly a l i g n e d ,  coarser grained jamesonite  the b a n d i n g  regate  can  jamesonite  This m i n e r a l occurs i n massive,  l o n g ( f i n e r g r a i n e d t h a n i n number One  veins).  banded  galena.  unstrained, although a  i n c o n t a c t w i t h g a l e n a and  a l r e a d y been mentioned.  .1 mm.  vein  by  i n d e c r e a s i n g o r d e r of abundance.  Jamesonite  or  surrounded  galena,  these m i n e r a l s from  by  Where prisms the main  Figure  65.  G a l e n a (g) i n c o n t a c t with, d o l o m i t e ( d ) . The a c i c u l a r c r y s t a l s o f b o u l a n g e r i t e (b) a r e a l i g n e d s u b p a r a l l e l to the g a l e n a dolomite contact. This type o f t e x t u r e i s suggestive of c o l l o i d a l d e p o s i t i o n of t h i s material. 1-Nicol. x 66.  Figure  66.  S i d e r i t e (s) f i l l i n g f r a c t u r e s i n t e t r a h e d r i t e (t). G o v e l l i t e (c) l i n e s the f r a c t u r e s . 1-Nicol. x 100.  90  mass o f  jamesonite.  Siderite that is  exhibit  excellent  commonly l i g h t  black.  An  occurs i n c o a r s e l y c r y s t a l i n e  X-ray  (rhomboxedral)  The  mineral  brown i n c o l o u r and w e a t h e r s d a r k brown powder p a t t e r n o f Rex  t h i s m i n e r a l i s manganiferous. cates  cleavage.  aggregates  the presence  o f Mn,  Mg,  A and  siderite  indicates  that  spectrographic analysis Ca  and  i n decreasing order  indiof  abundance.  Dolomite omite  has  differs  from  a g r e y c o l o u r , i t was  pattern.  siderite  only i n colour.  identified  from  Dol-  i t s X-ray  powder  The m i n e r a l o f t e n c o n t a i n s d i s s e m i n a t e d n e e d l e s  of  boulangerite. The sidered about  carbonate  t o have  the  started with  same t i m e  jamesonite.  stage  That  of hydrothermal the  introduction  as, or s l i g h t l y  these  two  of jamesonite  jamesonite dolomite  and  dolomite.  v e i n d u r i n g the l a t e quent  on The  on  t h e b a s i s o f the  the b a s i s of the presence  s p h a l e r i t e with f r a c t u r e s  c o n s i d e r e d as e v i d e n c e  introduction  of dolomite  at  the i n t r o d u c t i o n  period of hydrothermal The  of  between  of t h i s  and  powder  siderite  o f movement on  presence  less  brecciated  by b a r r e n  activity  of  flow  by i t s X - r a y  filled  f o r a weak s t a g e  of s i d e r i t e .  relations  i n the v e i n  containing boulangerite (identified  p a t t e r n ) and is  and  i s con-  m i n e r a l s must h a v e been more o r  contemporaneous i s c o n s i d e r e d l i k e l y texture  after,  activity  the subse-  breccia  F i g u r e 67»  A l t e r a t i o n of massive aggregates of f i n e g r a i n e d .jamesonite (.j) a l o n g f r a c t u r e s u n r e l a t e d t o cleavage of jamesonite. The a l t e r a t i o n o f jamesonite i s a yellow mixture of bindheimite and a n g l e s i t e ( b ) . The f u z z y r i m o f t h e f r a c t u r e s represents p a r t l y a l t e r e d jamesonite. 1-Nicol. x 25»  91.  texture  i n some c a s e s  and i t s a b s e n c e i n o t h e r s i s c o n s i d e r e d  to i n d i c a t e  that the carbonate  stage  essentially  continuous  t h a t was  process  by t h e weak b r e c c i a t i o n  o f m i n e r a l i z a t i o n was  an  not markedly i n t e r r u p t e d  o f some d o l o m i t e  after  i t had been  de-  posited.  Secondary  Alteration  Rex v e i n m a t e r i a l p r o v i d e s a good secondary relative  Textures  alteration.  secondary  minerals  p r o p o r t i o n s i n the v e i n are l i s t e d Goethite  54$  Bindheimite  40$  Anglesite  5$  Covellite  1$  shown by t h e s e Goethite  masses  The  Bindheimite canary  y e l l o w masses  tified  by i t s X - r a y  after  o r d e r o f abundance. admixed g o e t h i t e .  and t h e i r  of  estimated  below.  a r e d e s c r i b e d below.  grained,  admixed w i t h l e s s e r  and f i n e  amorphous  anglesite i n  grained aggregates,  powder p a t t e r n .  Cu w i t h  fine  f o r study  siderite.  occurs  of bindheimite  o f Sb, Pb, Pe, Ag,  minerals  o c c u r s a s brown,  a n d a s boxworks  of a mixture  secondary  example  and was  A spectrographic  and a n g l e s i t e  showed t h e  iden-  analysis presence  t r a c e s o f Sn and A l i n d e c r e a s i n g  I t i s c o n s i d e r e d t h a t i r o n may The p r e s e n c e  of s i l v e r  suggests  be due t o t h a t some o f  92:.  t h e m a t e r i a l may patterns since be  be  two  that  i n any  I n any  of a n g l e s i t e  o f the  secondary  and  case  this and  The  a r e v e r y much  are i s o s t r u c t u r a l  associated with  i s l a r g e l y made up noted  bindheimite  d e t a i l e d work.  are apparently  were n o t  and  minerals  separated with  ( 0 , OH).  2  of s t e t e f e l d i t e  these  values  s t e t e f e l d i t e Ag Sb206  the  two  powder alike, can  secondary  canary  silver  yellow  bindheimite.  only  mixture  Jarosites  a s s o c i a t i o n s from  Rex  vein. Bindheimite has  replaced that mineral  of a l t e r a t i o n Two  i s closely  evident  i n Rex  grained.  jamesonite  there i s coarse  by  cleavage  fractures  and  and  control number  grained, i s not  since jamesonite  of jamesonite  controlled  The  jamesonite  so common i n number One  mineralization,  Alteration  random and  along f r a c t u r e s .  of jamesonite,  v e i n s because  associated with  i s so  fine  a p p e a r s t o have been r a t h e r i n massive,  fine  grained  jamesonite.  Anglesite  occurs  show c o l l o f o r m b a n d i n g . portions with  as  The  thin,  grey  c o a t i n g s on g a l e n a  mineral i s also  present  i n smal  that pro-  bindheimite.  Covellite  lines  dolomite  filled  veinlets  in  tetrahedrite.  Paragenesis  Prom t h e  foregoing textural  d e s c r i p t i o n s the  paragenesis  Figure  68>  Van de V e e r d i a g r a m t o show p a r a g e n e s i s o f p r i m a r y and s e c o n d a r y m i n e r a l s i n Rex v e i n .  REX van de v e e r  VEIN paragenetic  diagram  anglesite  93  of the primary diagram This  arid s e c o n d a r y  showing  the paragenetic  The  'flow'  posited  colloidal  suggests  solutions.  on w a l l r o c k a n d o f g a l e n a banding  these m i n e r a l s  also.  the banding  and by  such  of sphalerite  w i t h m a m m i l l a r y and  a mode o f d e p o s i t i o n f o r colloidal  deposi-  o c c u r r e d i n number T h r e e v e i n i s b o r n e o u t  of siderite  from  temperature  that vein.  o f d e p o s i t i o n o f hydrothermal  number One, Two a n d T h r e e v e i n s . quoted  addition,  Crustification  A s u g g e s t i o n t h a t such  be e s t a b l i s h e d more c l o s e l y  eratures  proportions  o f D e p o s i t i o n and C l a s s i f i c a t i o n  The cannot  the r e -  t h a t t h e s e m i n e r a l s were d e -  on s p h a l e r i t e ,  seems t o s u p p o r t  t i o n may a l s o h a v e  Temperature  and the r e l a t i v e  t e x t u r e s e x h i b i t e d by j a m e s o n i t e  i n dolomite  reniform  but also  a n d v e i n i n g t e x t u r e s shown b y them.  boulangerite from  A Van de V e e r  s e q u e n c e i s g i v e n i n f i g u r e 68.  abundance o f t h e m i n e r a l s  of replacement  f o r these  however,  The same s e t o f maximum  500°C.  (This value  f o rthis  assemblage o f m i n e r a l s  In  tetra-  as b e i n g l e s s  i s q u e s t i o n a b l e , as d i f f e r e n t  g i v e n by v a r i o u s w o r k e r s f o r t h i s  The  stage  temp-  f o r Rex v e i n .  the e x s o l u t i o n o f c h a l c o p y r i t e from  g i v e s a temperature  minerals  t h a n h a s b e e n done f o r t h e  deposits hold also  hedrite  are  i s clear.  d i a g r a m shows n o t o n l y t h e p a r a g e n e s i s ,  lative  by  minerals  than  temperatures  exsolution point.)  i n Rex v e i n i s s u g g e s t i v e  94  of lower  temperatures  described deposits  veins. and  this  of d e p o s i t i o n than those  It i s characteristic gives  the  Zoning;'of the  in  the  exists  the  Van  de  gressive the  i n the  number One,  of r e l a t i v e  veins  Two,  and  described.  Three v e i n system  the  information w i l l anything  i s not  of p y r i t e  exists  veins and  for  zoning  i n the  form  A glance  r e v e a l s the arsenopyrite  concomitant  increase  in  h a v e t o be  obtained  from  of Vein  can  at proin  proportions  difficult  this  be  concerning  under-  both zoning  in  established.  Minerals  to g i v e  of hydrothermal a c t i v i t y , t i m e on  three  concrete  individual veins  Time o f Emplacement  a specific  Some e v i d e n c e  mineral-  galena.  g r o u n d work, b e f o r e  It  of  of hydrothermal minerals.  d e p o s i t s w e s t w a r d and  period  t h a t marked z o n i n g  decrease i n p r o p o r t i o n  camp and  temperature  250°C.  Veer diagrams f o r these  o f j a m e s o n i t e and  the  evidence  proportions  New  of  type  Deposits  T h e r e i s no ization  previously-  of mesothermal v e i n  v e i n a rough range  o f d e p o s i t i o n b e t w e e n 500°C and  o f the  stage.  but  a range i t i s not  o f time f o r p o s s i b l e to  the put  95 The This wall and  the  veins  r o c k has  contain not  fragments of b r e c c i a t e d w a l l  b e e n a f f e c t e d by h y d r o t h e r m a l  P h a s e I l i n e a t i o n on  been p r e s e r v e d .  these fragments of w a l l  T h i s means t h a t  f o r m e d a f t e r Phase I f o l d i n g . not is  noted  on  probable  The  b r e c c i a fragments, that  a l l the  the  veins  rock.  activity r o c k have  v e i n f a u l t s must h a v e  second phase l i n e a t i o n  e x c e p t i n number One were f o r m e d l a t e r  was  vein.  It  than Phase  II  folding.  It or during  seems l i k e l y  the  period  and  i t is likely,  was  r e l a t e d to the  emplaced  to  the  v e i n f a u l t s were f o r m e d  when i n t r u s i o n o f g r a n i t i c  but  not  rocks  occurred  c e r t a i n , that hydrothermal  granitic  rocks  and  before  activity  that vein minerals  were  shortly after intrusion.  It prior  that  the  H a g g a r t and  is fairly regional Secret  c e r t a i n that faults  Creeks.  that Rex  the  trend  fault  vein  f a u l t s were  north  south  i s o f f s e t by  formed  along Secret  Creek  fault•  It occurred and is  i s not  c e r t a i n t h a t m i n e r a l i z a t i o n o f Rex  similtaneously  Three v e i n f a u l t s , slightly  number One, alized  different. Two  and  fault  w i t h m i n e r a l i z a t i o n o f number One, since On  the m i n e r a l o g y  the  Three v e i n s  contemporaneously.  basis are  of  these  two  Two systems  of s i m i l a r mineralogy thought  the  t o have b e e n m i n e r -  A l t h o u g h m i n e r a l i z a t i o n o f Rex  vein  96  is  different  evidence  from  t h a t o f number One,  to suggest  poraneously  with  them i s  In s h o r t , the  same t i m e ,  t h a t Rex  and may  presented  shortly  after  igneous  the  time  i n t r u s i o n and  of i n t r u s i o n  c o n c l u s i o n s drawn f r o m form  to t h i s  this  study  of a geologic h i s t o r y ,  gives only r e l a t i v e  of  vein  faults  granodioritic  intrusion.  GEOLOGIC HISTORY  below i n c h r o n o l o g i c a l o r d e r . sented  no  n o t m i n e r a l i z e d contem-  e v e n h a v e b e e n f o r m e d due  i n the  Three v e i n s ,  found.  SUMMARY OP  The  v e i n was  and  t h e r e f o r e , t h e v e i n s were m i n e r a l i z e d a t  were f o r m e d a t o r b e f o r e rocks  Two  The  times  can  best  which i s s e t  g e o l o g i c h i s t o r y here  as a b s o l u t e  be  times  are  out pre-  not  available. 1.  D e p o s i t i o n o f a sequence o f impure  s i l t s t o n e s with  interbedded  d e p o s i t i o n has  not  argillaceous rocks.  been worked out  i n the  area.  sandstones  The  The  order  since stratigraphic  general  structural  and  were n o t  found  from  top  to bottom i s :  1.  Massive grey q u a r t z i t e , with black p h y l l i t e interbedded black limestone.  2.  Micaceous  quartzite with  interbedded  grey  3.  Micaceous s t o n e and  quartzite with greenstone.  interbedded  phyllite,  of  tops  sequence  and  minor  phyllite. lime-  97  The  lower u n i t  i s considered  the  Upper S c h i s t  on  Keno and  2.  Isoclinal folding  foliation  accompanied  of  regional  3.  folding  considered  isoclinal  folds  axes.  that  had  I I was  the  Phase I I  stress  on  Keno and by  map  including  Phyllite  was  - Tin H i l l  Intrusion  possibly sill  of  including like  south of i n an  the  i n the  of  the  effect  Highest  the  Rex  eastward the  Phase I  the  on  was  northwestward deformation  area i n question. of Phase I I are  that  the  centre  of  Phase  more marked strongest  area. direction  f a u l t and  perhaps a l s o  This  sub-  metamorphism.  the  map  or  folding  Phase I f o l d i n g  e a s t west  fault.  shearing  essentially a brittle  Effects  with,  plunging  e a s t west t r e n d i n g ,  foliation  in  grade  foliation  of  plane  facies.  foliation.  some r e g i o n a l  area i n d i c a t i n g  quartz d i o r i t i c  6.  the the  of  produce bedding  Galena H i l l s .  P h a s e I I was  Faulting  faults  to  metamorphism.  folding  produced  w e a k e r t h a n Phase I .  5.  shearing  a late  only minor e f f e c t  south of  is  be  Phase I I f o l d i n g  has  correlative  Hills.  o v e r s o u t h s e n s e on  to have produced  plunging  of  and  that  p r o b a b l y accompanied 4.  or  regional  P h a s e I f o l d i n g may  isoclinal  a possible  Galena  subisoclinal  p r e d o m i n a n t n o r t h up  is  by  be  metamorphism r e a c h e d i s g r e e n s c h i s t  Phase I ,  axes.  to  f a u l t i n g may  to produce the  be  vein  Black  due  to  intrusion  rocks. of  quartz d i o r i t i c  augitite w e s t and  ?.  The  rocks  and  related  shape o f  the  i n t r u d e d mass  becomes p r o g r e s s i v e l y  more  types,  trans-  98.  gressive  and t h i c k e r Motion  ( s t o c k l i k e ) i n the e a s t .  o f t h e magma d u r i n g i n t r u s i o n  h a v e b e e n f r o m west  to east.  The magma i s t h o u g h t  a c r y s t a l mush ( a b o u t Zyfo s o l i d ) t o have b e e n i n t r u d e d The about  f o r part  temperature  during intrusion  of i t s length  o f the i n t r u d i n g  of intrusion  i s thought  t o have  been  and i s thought  along a f a u l t .  mass i s p l a c e d a t  600°C a n d t h e d e p t h b e l o w t h e s u r f a c e  r o c k s a t t h e time  i s thought t o  of granodioritic  t o have been  about  twelve k i l o m e t r e s o r l e s s . Intrusion  o f quartz f e l d s p a r porphyry  to have accompanied dioritic  or followed shortly  Thermal  sedimentary  metamorphism  west.  Thermal  The h i g h e s t g r a d e hornfels  facies,  hornfels  facies.  by  o f the r e g i o n a l l y  effects  were d e t e c t e d a r o u n d  but the h i g h e s t s t a b l e  followed  closely.  into  pyroxene  i s hornblende  Corundum h a s d e v e l o p e d m e t a s t a b l y n e a r t h e The t h i c k n e s s o f t h e zone o f r o c k s  Low g r a d e  imperceptably  facies  No  the s i l l to  o f t h e r m a l metamorphism a p p r o a c h e s  contact.  feet.  8.  o f quartz  metamorphozed  metamorphism f o l l o w e d i n t r u s i o n  t h e r m a l metamorphism i s t h o u g h t  sand  intrusion  rocks surrounding the quartz d i o r i t e stock.  thermal metamorphic  igneous  i s thought  rocks.  7.  the  after  dykes  t o be l e s s  thermal metamorphic  t h a n one t h o u -  assemblages  s u r r o u n d i n g r e g i o n a l metamorphic  Metasomatism accompanied i t closely.  Its effects  affected  pass assemblages.  t h e r m a l metamorphism o r are very minor  and c o n s i s t  99  largely The by  of  formation  formation  o f m i c a s from  these minerals  9.  i s thought  t o be  the  Two  and  galena-tetrahedrite tiferous other  and  Three v e i n s combinations  which are  origin.  quartz  deposits  bearing  dioritic  that  quartz-gold  t h i s m i n e r a l i z a t i o n , but n e a r the rocks  surface  and  that  at  the  associations  discussion,  veins  are  veins  quartz  i n vein  diorite.  tourmaline  occurs  and  i t i s considered time of  skarn  Cassiterite on  Tin  i n the  that  i n t r u s i o n of  to  placer  associated t h e s e were  quartz  with formed  dioritic  w e a t h e r e d away.  deposits  and  area as  includes  disseminations  mineralization associated  with  Hill.  G l a c i a t i o n during g l a c i a l periods  several  found c l o s e  were o r i g i n a l l y  O t h e r m i n e r a l i z a t i o n i n the map scheelite  argen-  occur.  There i s evidence  t h e y a r e now  of  v e i n , which are  i n this  arsenopyrite  stock.  Aside  siderite-jamesonite-  o f Rex  described  types of m i n e r a l i z a t i o n Gold  and  be  p o t a s h metasomatism.  of metasomatic  arsenopyrite-jamesonite-siderite  number One,  two  corundum.  Hydrothermal m i n e r a l i z a t i o n of v e i n f a u l t s .  from  10.  and  i s thought to  r e t r o g r e s s i v e metamorphism i n i t i a t e d by  Some t o u r m a l i n e  the  of micas from a n d a l u s i t e  the  pleistocene.  i s found w i t h i n  the map  Evidence area.  for  in  BIBLIOGRAPHY  Aho, A.E. ( 1 9 ^ 9 ) , " M i n e r a l o g y o f some heavy sands o f t h e McQuesten R i v e r A r e a , Y.T.", B.A.Sc. Thesis,U.B.C. unpublished. Aho, A.E. 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" E v o l u t i o n o f metamorphic r o c k s " ,  W i s e r , E.H., ( I 9 6 0 ) , " R e l a t i o n o f Ore D e p o s i t s t o Doming i n t h e N o r t h A m e r i c a n C o r d i l l e r a " , G.S.A.Mem. 7 7 .  L E G  E N D  Camaara*  aia*ai  Par/l/n'.e  M*,I**/*>**' MUrff  Oaarrr  aassat  la.ttaat  aar»a 't  M'ai.ra  iiat.fa  fa a.min*  mimaa*i*\tii*  A  ain't*  im wan •«*•/,*»««»* - ••' i*rt arar- waaa ••'  o  Q  •" « . - »• tmiaar aiaaa  -J  Biata  mat  Orar  t'*r, *a,ii>ta  f*,Hllm  t'ar  Q.i.l,  Onifaa  <tr*a */  Fatiari  ~—~  ' -a* VMM  B '  araa  a-mariura »*rmtmi  lutr'n ra liUmmhtmti  «  Imiaai  aaarlt  "if " r  it ait t **airt,i»}  *>i ta  ita.tr/  aa a i > 11 'a . * • a~» I aai la  •tlemtaaat aaattfa (mlaai it . I ' I D  -*»•"»  aaa  aaannra.aaa'ii aajiina t—taa' t"  fSf/ma  M'tataaaa  <U  t  titan,aa  , taarH aarartltl  ar'afa't  tiaia'ta  amratalt  fmtm  . , *> aft r > tfaa I a * r ' a i a mai»af »/ f l a a i , BI a aa alt tatatif r  arr-lata tartaat  a*  J««mfiaf  Ltaaa'laa ttiae\'r fmit a • am '1."  "N. Ctaraar Saa t t  tiatiirai  /OO  Itat ta-itiaa  P E S O SILVER M I N E S LTD (NPL)  Mayo  Yukon  REGIONAL GEOt-OGY  t  4  M.N.  L E G E N D Granodiorite Massive 1  quartzite  j M i c a c e o u s quartzi te Phyllite C a l c a r e o u s quartz .<;+  STRUCTURAL HAGGART  s a  M  CREEK - DUBLIN  TREND M A P GULCH  AREA  w ~ ^ r  contour  interval  5 0 0 feet  ,  YUKON  Fault Foliation  trend  ( t e e t h in dip  direction)  ELEVATIONS  IN F E E T  ABOVE MS.L  L E G E N D  Granodiorite Massive Quartz  quartzite mica  Micaceous Feldspathic  schist quartzite quartzite  Shale e t c O © imm  Mine, prospect Fault  —*****  Contact A t t i t u d e of b e d d i n g  mm — •  Ridge Road Settlement Lake C r e e k or River Limit of e x t e n s i v e till c o v e r  -vr  or  showing  P E S O  foliation  S I L V E R  B L O C K POTATO  M I N E S  D I A G R A M  HILLS- MOUNT HALDANE KENO HILL AREA M a y o district , Yukon  Draw n  G E O L O G Y  G E N E R A L I Z E D  Compiled Interpreted  by  DTK  March  1964  

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