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A petrographic study of the relationship of the Timiskaming [sic] to Grenville subprovince 1947

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A PETROGRAPHIC STUDY OF THE RELATIONSHIP OF THE TIMISKAMING TO GRENVILLE SUBPROVINCE BY WILLIAM GEORGE.JOHNSTON A Thesis submitted i n P a r t i a l F u l f i l m e n t of The Requirements f o r the. Degree of MASTER OF APPLIED SCIENCE i n the Department of GEOLOGY AND GEOGRAPHY THE UNIVERSITY OF BRITISH COLUMBIA. APRIL 1947 4~/74-7. ACKNOWLEDGMENTS The w r i t e r i s p a r t i c u l a r l y indebted f o r a s s i s t a n c e and guidance r e c e i v e d from Dr. H.C. Gunning of the Department of Geology and Geography under whom t h i s t h e s i s was attempted. Ass i s t a n c e from other members of the s t a f f of the Department of Geology and Geography i s a l s o gratefully'acknowledged, and a l s o the r e c e i p t of two specimens of K i l l a r n e y g r a n i t e from Dr. E.L. Bruce of the" Department of Geology, Queen's U n i v e r s i t y , Kingston, Ontario. ' ABSTRACT A study of the g r a n i t i c rock types along the Contact of the Tiralskatning and G r e n v i l l e subprovinces to the east of lake Timagami has been made. In the v i c i n i t y of the contact of the two subprovinces i n the g r a n i t e s of the G r e n v i l l e subprovince i s a wide zone of f a u l t i n g near which the rocks show, wide spread c a t a c l a s t i c texture - due to crushin g . In t h i s area the g r a n i t e i n the G r e n v i l l e sub- province i s very d i s t i n c t from the Algoman g r a n i t e of the Timiskaming subprovince and l a t e r than i t . The g r a n i t e i n . the G r e n v i l l e subprovince i s much f r e s h e r than the Algoman g r a n i t e and u n l i k e the Algoman i s high i n potash f e l d s p a r as determined by Rosiwal analyses. In the l a t t e r and other respects i t s t r o n g l y resembles the K i l l a r n e y g r a n i t e i n Pardo and Dana townships and to the south along the north shore of lake Huron. In S i s k township i t contains a r a t h e r rare amphibole h a s t i n g s i t e which i s a l s o found i n the Creighton g r a n i t e of K i l l a r n e y age. CONTENTS PAGE INTRODUCTION - 1 SUMMARY OF THE LITERATURE 5 PRESENT WORK 12- FIELD OBSERVATIONS , 1 3 , TIMISKAMING SUBPROVINCE 13 CONTACT ZONE 14 • GRENVILLE SUBPROVINCE 14 LABORATORY STUDY . 16 ALGOMAN INTRUSIVES 16 INTRUSIVES IN.THE GRENVILLE SUBPROVINCE 17. DIFFERENCES BETWEEN THE ALGOMAN AND THE GRANITE OF GRENVILLE SUBPROVINCE 19 COMPOSITIONAL DIFFERENCES 20 RELATION BETWEEN THE ALGOMAN AND GRENVILLE INTRUSIVES 26 CORRELATION OF THE GRANITE IN THE GRENVILLE WITH THE KILLARNEY GRANITE 27 THE PRE TIMISKAMING GRANITE 27 CONCLUSIONS 29 ILLUSTRATIONS . 32 BIBLIOGRAPHY "• 40 MAP IN BACK POCKET. 1 •A PETROGRAPHIG STUDY OF THE RELATIONSHIP OF THE TIMISKAMING TO GRENVILLE SUBPROVINCE. INTRODUCTION The contact between the Tiiniskaming and G r e n v i l l e g e o l o g i c a l subprovinces of the Canadian s h i e l d i s a f a i r l y s t r a i g h t l i n e , t r e n d i n g north-east from K i l l a r n e y on Georgian Bay to the f o o t of lake Timiskaming, and beyond as f a r as mapping has been c a r r i e d out. ( F i g u r e , page 2.) The northern p o r t i o n of the Timiskaming subprovince i s l a r g e l y " g r a n i t e " which contains i n i t bands of Keewatin and Timiskaming s e r i e s c l o s e l y f o l d e d along east west axes. In the K i r k l a n d Lake area and to the east these s e r i e s appear conformable; however at Porcupine there i s a very d e f i n i t e unconformity, as a l s o e x i s t s between rocks classed as Keewatin and Timiskaming i n north-western Ontario. The Keewatin i s predominantly composed of lava'and p y r o c l a s t i c s interbedded w i t h minor amounts of i r o n formation and c l a s t i c sediments. The Timiskaming s e r i e s i s made up of some con- glomerate, c l a s t i c sediments and l a v a s . In the-area to the n o r t h of lake Wanapetei and to the west of lake Timiskaming the -above rocks are o v e r l a i n by the Cobalt s e r i e s composed of conglomerate, s l a t e conglomerate, and s l a t e o v e r l a i n by q u a r t z i t e . In the southern p o r t i o n of the area the S t o b i e , Coniston and H i l l groups may correspond to the Keewatin and Timiskaming. These rocks are thought to be pre-Huronian although t h i s i s not a b s o l u t e l y c e r t a i n . The Stobie and Coniston groups to the south of the Sudbury b a s i n are f a u l t e d  upward against the Bruce s e r i e s the lowest member of the Hur- onian. The three members of the Huronian, the Bruce, Cobalt and Whitewater are separated by unconf o r m i t i e s . I n t r u s i v e rocks are represented by the Nip-is s i n g diabase and the Sudbury n i c k e l e r u p t i v e , both,of which are cut by the K i l l a r n e y g r a n i t e . The l a t e s t Igneous rock i s an o l i v i n e diabase which i s represented by small but wide-spread dykes. TABLE OF FORMATIONS OF THE TIMISKAMING SUBPROVINCE NORTHERN PORTION SOUTHERN PORTION MODIFIED AFTER COOKE O l i v i n e diabase Trap (dykes) K i l l a r n e y , Murray Keweenawan and Creighton g r a n i t e s N o r i t e and Micro- pegmatite Whitewater s e r i e s Period of e r o s i o n O l i v i n e diabase Upper O l i v i n e ' d i a b a s e Huronian . B i r c h Lake Granite? Nip i s s i n g . diabase (Animikie) N i p i s s i n g diabase Intense f o l d i n g p o s s i b l y g r a n i t e i n t r u s i o n . Cobalt S e r i e s Middle Huronian - Cobalt "Series ' Unconformity Lower Huronian - Bruce S e r i e s . Pre-Huronian Matachewan diabase Algoman g r a n i t e Intense f o l d i n g Granite i n t r u s i o n , probably f o l d i n g Timiskaming S e r i e s Stobie Group, L o c a l unconformities . H i l l Group Keewatin = Coniston Group. A d e t a i l e d account of the geology of the G r e n v i l l e subprovince w i l l not be attempted here. I t w i l l s u f f i c e to say the rocks of that s e r i e s i n the area under d i s c u s s i o n are composed of b i o t i t e and hornblende gneisses which have i n some places been i n t i m a t e l y i n t r u d e d i n l i t - p a r - l i t f a s h i o n by g r a n i t i c m a t e r i a l . G n e i s s i c , pink and grey g r a n i t e s occur at M a r t i n r i v e r and e s p e c i a l l y along the contact between the two subprovinces. The southern.portion of t h i s contact i s of p a r t i c u l a r i n t e r e s t . To the east of i t the Huronian sediments which continue 500 miles to the west and reach thicknesses of 23,000 f e e t suddenly disappear d i a g o n a l l y across t h e i r s t r i k e against a great area of g r a n i t e gneiss s e p a r a t i n g the rocks of the Timiskaming subprovince from those of the G r e n v i l l e and Hastings s e r i e s , occuring i n greatest p r o f u s i o n some 150 miles to. the south-east. Attempts to c o r r e l a t e the rocks across t h i s area have so f a r f a i l e d as the sedimentary remnants i n t h i s i n t e r v e n i n g g r a n i t e are too h i g h l y metamor-: phosed. Since a c o r r e l a t i o n of the sediments i s impossible the r e l a t i v e ages of the g r a n i t e i n each subprovince might shed some l i g h t on the r e l a t i v e ages of the other r o c k s . A l l previous work toward s o l v i n g t h i s problem has been done from Georgian Bay as far. n o rth as Sudbury. The work done by the w r i t e r i s based on f i e l d work f a r t h e r north-east along the boundary of the two subprovinces i n the v i c i n i t y of the trans-Canada Highway and the Timiskaming and Northern Ontario R a i l r o a d . 5 SUMMARY OF THE LITERATURE Many c o r r e l a t i o n s between the G r e n v i l l e and Timiskaming subprovinces have been* proposed. I n 1907 M i l l e r (1) page 49 and (3) page .221-223 s t a t e s that he considered the Keewatin i r o n formation at Cobalt part of the G r e n v i l l e s e r i e s which was much b e t t e r developed i n southeastern Ontario and i n the adjacent parts, of Quebec. He considered the o v e r l y i n g Hastings s e r i e s i n south-eastern Ontario as being s i m i l a r to the Hurohiah. M i l l e r and Knight (3) page 281 and 1913 (4) set f o r t h much the same c o r r e l a t i o n . They c o r r e l a t e d a s e r i e s o f ' v o l c a n i c s i n the' Madoc d i s t r i c t w i t h the Keewatin. They b e l i e v e d the G r e n v i l l e s e r i e s o v e r l a y the Keewatin and the two were separated by an e r o s i o n a l unconformity. Both had been intruded by the L a u r e n t i a n g r a n i t e and were o v e r l a i n unconformably by the Hastings s e r i e s l a t e r i n t r u d e d by the Algoman .granite. Geologists (5) f o r some years f o l l o w e d t h i s c l a s s i f i c a t i o n . The g r a n i t e which had i n t r u d e d the sediments i n l i t - p a r - l i t f a s h i o n was c a l l e d L a u r e n t i a n while that i n l a r g e r dykes and stock l i k e masses was c a l l e d Algoman. L a t e r work by Wilson (6) and Harding (7)- has shown that the G r e n v i l l e and Hastings are r e a l l y a conformable group and that there i s probably only one g r a n i t e i n the G r e n v i l l e subprovince. While the controversy over the age r e l a t i o n s between References r e f e r to the b i b l i o g r a p h y , page 40 6 the Timiskaming and G r e n v i l l e subprovinces was t a k i n g place the f a c t that a post Huronian g r a n i t e e x i s t e d on the north shore of lake Huron was e s t a b l i s h e d . Murray (8)had described a' post Huronian g r a n i t e i n 1849. L a t e r g e o l o g i s t s d i s - c r e d i t e d h i s observations; and i t was not u n t i l 1925 that ' C o l l i n s showed Murray's observations were the a c t u a l case. i The only r e a l endeavour to solve the problem of the r e l a t i o n s h i p between the two subprovinces was c a r r i e d out by Quirke and C o l l i n s ( 9 ) , who mapped a lar g e area on the north shore of lake Huron from K i l l a r n e y east and northward to lake N i p i s s i n g . C o l l i n s and Quirke conclude the K i l l a r n e y g r a n i t e extends eastward from K i l l a r n e y at l e a s t to lake N i p i s s i n g . They consider there i s some reason to b e l i e v e that the g r a n i t e of the G r e n v i l l e subprovince may be K i l l a r n e y i n age. According to t h e i r observations the K i l l a r n e y g r a n i t e i s i n sharp i n t r u s i v e contact w i t h the Huronian sediments (eastern extremity of the Timiskaming subprovince;- ). This contact has been the locus of a great f a u l t w i t h displacement east side up. The area to the south east of t h i s f a u l t c o n s t i t u t e s one of the deepest h o r i z o n t a l s e c t i o n s anywhere- exposed on the earth's c r u s t . To the south-east of t h i s contact l i n e are found remnants of the Cobalt and Bruce s e r i e s which can be unmistakenly c o r r e l a t e d w i t h the unmetamorphosed Cobalt and Bruce s e r i e s to the west up to f i v e miles from the g r a n i t e sediment contact. Beyond t h i s the h i g h l y metamorphosed character of the remnants makes d e f i n i t e c o r r e l a t i o n imposs- i b l e . The profound metamorphism of.these remnants i s due to the depth of b u r i a l and h i g h temperatures. The contact aureoles around i s o l a t e d masses 'of K i l l a r n e y g r a n i t e are very minor. The gneisses are composed of Huronian sediments t r a n s - formed to g r a n i t i c m a t e r i a l by pressure, heat and chemical change operative at great-depth. The evidence they give f o r t h i s i s : (a) The minerals are 'crowded w i t h i n c l u s i o n s and there i s (b) a very close s i m i l a r i t y i n the chemical compos- i t i o n between the " i n t r u d i n g " and intruded m a t e r i a l , (c) the quartz, grains of the igneous p o r t i o n of the gneisses and of some g r a n i t e have a d e t r i t a l appearance. They e x p l a i n the unconformity produced by the north- west trend i n the gneisses near lake N i p i s s i n g as being due to r a d i a t i n g f o l d s from a centre near Burwash. They show that age determinations on r a d i o a c t i v e minerals from the K i l l a r n e y i n t r u s i v e s and the G r e n v i l l e subprovince appear to agree f a i r l y c l o s e l y . The suggestions put f o r t h by Quirke and C o l l i n s that the sedimentary p o r t i o n of the G r e n v i l l e subprovince i s Huronian has been questioned by some g e o l o g i s t s . Wilson,'s (10) o b j e c t i o n s are as f o l l o w s : " l . The b e l t of banded gneisses that occurs on the shore o'f Georgian Bay between K i l l a r n e y and Parry Sound . continues n o r t h - e a s t e r l y to the south end of Lake Timiskaming and beyond f o r many hundreds of m i l e s , whereas the K i l l a r n e y g r a n i t e as shown by i t s i n t r u s i v e r e l a t i o n s to the Huronian Cobalt s e r i e s terminates east of Lake Wanapitei, almost midway between Georgian Bay and Lake Timiskaming. I f the K i l l a r n e y g r a n i t e terminates i n a north e a s t e r l y d i r e c t i o n , i s i t not probable that i t terminates i n a s o u t h - e a s t e r l y d i r e c t i o n as w e l l ? 2. I f the K i l l a r n e y g r a n i t e were i n t r u d e d i n t o a b e l t of banded, gneisses i t would almost c e r t a i n l y i n j e c t i t s e l f along t h e i r planes of f o l i a t i o n and banding so that i t s contact would be t r a n s i t i o n a l j u s t as Quirke and C o l l i n s have described. 8 3. The G r e n v i l l e s e r i e s , throughout most of the G r e n v i l l e subprovince, except i n l o c a l areas around the margins of some b a t h o l i t h s , c o n s i s t s of i n t e r s t r a t i f i e d c r y s t a l l i n e limestone, mas.sive q u a r t z i t e resembling v e i n quartz i n appearance, and s i l l i m a n i t e garnet gneiss having the texture of g r a n i t e but the chemical composition of pure shale. As one proceeds northward i n t o the b e l t of banded gneisses that separates the G r e n v i l l e from the Timiskaming subprovince the presence of G r e n v i l l e sediments i s i n d i c a t e d by areas of t r e m o l i t i c limestone, bands of q u a r t z i t e contain- ing f e l d s p a r c r y s t a l s along minute f r a c t u r e s and b e l t s of garnet gneiss. The banded gneisses i n the i n t e r v e n i n g areas as shown by chemical a n a l y s i s have the composition, f o r the most p a r t , of normal g r a n i t e or i n places of d i o r i t e and there i s l i t t l e i n t h e i r chemical compositions to i n d i c a t e that large amounts of G r e n v i l l e s e r i e s have been transformed d i r e c t l y Into g r a n i t e or g r a n i t e gneiss i n the manner that C o l l i n s and Quirke b e l i e v e to have, occurred i n the case of the Huronian of the K i l l a r n e y d i s t r i c t . • 4. I f a l a r g e part of the g r a n i t e of south-eastern Ontario or of the b e l t of banded gneisses of K i l l a r n e y age and the K i l l a r n e y g r a n i t e was intruded during the Keweenawan then t h i s r e g i o n was mountain-built and denuded to a pene- p l a i n i n the i n t e r v a l that elapsed between the Keweenawan and the e a r l y P a l a e z o i c , when the sediments of t h i s age that now r e s t on the surface of the Pre-Cambrian were deposited. I t i s doubtful whether a l l t h i s could occur i n so short an i n t e r v a l of time. 5. The Keweenawan, according to the report of the Committee of the United States Research C o u n c i l on the measurement of g e o l i g i c time, ranges i n age from 510 to 550 m i l l i o n years. The age of the g r a n i t e s , or pegmatites associated w i t h g r a n i t e , i n south-eastern Ontario i n 17 out of 20 a n a l y s i s of u r a n i n i t e as t a b u l a t e d by E l l s w o r t h range from 985 to 1,125 m i l l i o n years. Three analyses of u r a n i n i t e i n Henvey township, w i t h i n the area mapped by Quirke as K i l l a r n e y , gave r a t i o s equivalent to 835, 792 and 792 m i l l i o n years r e s p e c t i v e l y . E l l s w o r t h states that the Henvey "ma t e r i a l i s not i n the best stage of p r e s e r v a t i o n , but nevertheless i t s r a t i o i s so much lower than any of the other u r a n i n i t e s that i t must be considered as probably r e a l l y younger". ...... According to these determinations, t h e r e f o r e , the g r a n i t e s of south-eastern Ontario w i t h the p o s s i b l e exception of those i n Henvey township were probably intruded during the l a t e Archean and are not of K i l l a r n e y age". In a recent p u b l i c a t i o n Cooke (11) a l s o seems to d i s - f a v o r Quirke and C o l l i n s views although a d m i t t i n g the presence of a post Huronian g r a n i t e . He says; (11) page 6, 9 "The w r i t e r has discovered two remnants of pre-Huronian formations,, which he terms the H i l l and Goniston groups. Their p o s i t i o n i n the s t r a t i g r a p h i c column.is otherwise unknown, hut the di s c o v e r y ,of the Coniston group may have an important bearing on the problem"'. F u r t h e r he points out, (11) page 11, .They (chert bands i n the Conistan Group.) do seem to resemble the published d e s c r i p t i o n s , of the so- c a l l e d " i r o n formation" of the G r e n v i l l e s e r i e s i n south- eastern Ontario. He a l s o says (11) pages 16, 17, and 18; "the disc o v e r y of these rocks and t h e i r r e l a t i o n s has a d i r e c t bearing on the conclusions .announced by Quirke and C o l l i n s i n "The Disappearance of the Huronian". In that work these authors decide that c e r t a i n remnants of sediments found i n the gra n i t e here and there between K i l l a r n e y v i l l a g e and Delamere township are remnants of Huronian formations. They base t h i s c o n c l u s i o n , very soundly, on the f a c t that the v petrographic character of these much metamorphosed remnants i s such t h a t they could have been" formed from the d i f f e r e n t members of the Huronian system; and tha t where two or more members are found, t h e i r succession i s the same as i n the unmetamorphosed Huronian succession. " I t w i l l be observed that the remnants they describe l i e o n l y about 24 miles south of the contact described i n t h i s r e p o r t . The w r i t e r made a c r o s s - s e c t i o n from the contact to Wanup S t a t i o n , a distance of 6 m i l e s , and w i t h i n that distance a l l remnants of sediments belong i n d u b i t a b l y to the Coniston group, and a l l dip to the south. Throughout that d i s t a n c e , again, there, i s continuous evidence of up- th r u s t s from the south." "These two f a c t o r s oppose one another, i n c o n s i d e r i n g . what may have happened i n the remaining 18 miles to the sedimentary remnants described by Quirke. I f the southern dip i s continued, i t i s quite p o s s i b l e t h a t w i t h i n t h a t •distance some s t r a t i g r a p h i c a l l y o v e r l y i n g s e r i e s may come i n , , and that s e r i e s could w e l l be of Huronian age. On the other hand, the c o n t i n u i n g u p l i f t on the .south, due apparently to b a t h o l i t h l c i n j e c t i o n from below, by t i l t i n g the whole r e g i o n upward from a hinge l i n e on the C o n i s t o n - M i s s i s s a g i contact . would cause the Coniston group to continue much f a r t h e r t o the south than i t normally would, and might even e l i m i n a t e e n t i r e l y the younger s t r a t a . Only a f u r t h e r study of t h i s i n t e r e s t i n g s e c t i o n could d i s c o v e r what a c t u a l l y happened; i n the meantime i t would be best to regard Quirke's conclusions as t e n t a t i v e , and p o s s i b l y subject to r e v i s i o n " . P e t t i J o h n (12) has made a p e r t i n e n t remark which has d i r e c t bearing on t h i s problem. He says; 10 "One of the most s t r i k i n g f e atures of the Archean i s the s i n g u l a r s c a r c i t y of true q u a r t z i t e and almost t o t a l l a c k of limestone. The G r e n v i l l e , considered Archean by.some, contains both limestones and q u a r t z i t e s 'If i t be Archean, i t represents a very d i f f e r e n t species of sedimentation than the Archean sediments" s(of northern and northwestern O n t a r i o ) . In northern Quebec Gussow (13) has c o r r e l a t e d a g r a n i t i c mass w e l l w i t h i n the Timiskaming subprovince w i t h the g r a n i t e of the G r e n v i l l e subprovince on the b a s i s of chemical compos- i t i o n . This would i n d i c a t e that c a r e f u l study might b r i n g more such g r a n i t e masses to l i g h t which would be of great importance i n the s o l u t i o n of the age r e l a t i o n s h i p s between the two subprovinces. The. only other d e s c r i p t i o n of an i n t r u s i v e w i t h i n the Timiskaming subprovince which might be suspected of belonging to a p e r i o d of a c i d igneous a c t i v i t y other than the Algoman and Laurentian has been described by M i l l e r (1) page 65 at Cobalt. "Two t h i n r o c k - s e c t i o n s examined show i t to. be made up of f e l d s p a r , quartz and a colored c o n s t i t u e n t . The f e l d s p a r predominates and c o n s i s t s of m i c r o c l i n e , and an a c i d p l a g i o - clase showing f i n e a l b i t e tv/inning l a m e l l a e . ...» The c o l o r e d c o n s t i t u e n t i s not abundant. ' I t was apparently a mica, but i s now represented by c h l o r i t i c m a t e r i a l . This dyke i s not u n l i k e c e r t a i n small dykes i n the Montreal R i v e r area (James township etc.) known as a p a l i t e s . The l a t t e r a re, however, g e n e r a l l y under eighteen inches i n width, while that on the U n i v e r s i t y property averages about f i f t y f e e t . " The f o regoing i s a b r i e f summary of the broader phases of the problem c h i e f l y from a point of view of the area from K i l l a r n e y to Sudbury. The area under present c o n s i d e r a t i o n was f i r s t mapped i n a r a p i d reconnassance manner by A.E. Barlow. He w r i t e s (14); "The g r a n i t e on both sides .of lake Timiskaming appear to 11 grade g r a d a t i o n a l l y i n t o g n e i s s i c forms. The l a t t e r show many v a r i a t i o n s , and o f t e n pass a b r u p t l y from d i o r i t e - g n e i s s i n t o g r a n i t e - g n e i s s , the l a t t e r being by f a r the most prevalent- type." In t h i s same work Barlow describes the l a r g e mass of N i p i s s i n g l i k e diabase i n F l e t t and Angus townships which he b e l i e v e d o l d e r than the surrounding g n e i s s . Todd (15) i n a much l a t e r work says ; "In the southern g r a n i t e area (south east of Rabbit lake and the Matabitchuan r i v e r ) the three or more ages or generations of g r a n i t e and g r a n i t e gneiss and pegmatite pres- ent have been g r e a t l y b r e c c i a t e d and intermixed by f a u l t movements." Todd b e l i e v e s the Cobalt sediments o v e r l y a l l three ages of g r a n i t e . Bruce (16) has mapped a g r a n i t e i n Pardo and Dana townships which he considers to be K i l l a r n e y . Quartz b i o t i t e gneisses apparently s i m i l a r to those i n the townships of O l i v e , M i l n e , F l e t t and S i s k he assigned t e n t a t i v e l y to the Sudbury s e r i e s . F a i r b a i r n (17) from work i n the townships of Scadding, Davis, S t r e e t and Longhrin considers the rocks c l a s s i f i e d as Sudburian by Bruce are Cobalt sediments which have been g r a n i t i z e d at great depth and are separated from the u n g r a n i t i z e d sediments by a f a u l t whose displacement i s east side up. From the foregoing i t i s seen there are various possib- i l i t i e s f o r the age of the g r a n i t e of the G r e n v i l l e sub- province i n the area adjacent to the Timiskaming subprovince. • •These are: 1. Pre Keewatin 2. Laurentian (post Keewatin and pre Timiskaming) 3. Algoman 4. K i l l a r n e y . . 12 No g r a n i t e has as yet been i d e n t i f i e d as pre-Keewatin "in the Timiskaming subprovince. I t seems improbable that such a large area of pre-Keewatin g r a n i t e could e x i s t without some evidence of i t s presence. However, a pre-Keewatin g r a n i t e would e x p l a i n the presence of g r a n i t e pebbles i n the Timiskaming conglomerates which are apparently conformable i n some areas w i t h the Keewatin b e t t e r than a L a u r e n t i a n g r a n i t e f o r which there i s l i t t l e i f any evidence. An Algoman g r a n i t e would not e n t i r e l y e x p l a i n the disappearance of the Huronian. Even a great u p l i f t along the eastern side of the contact of the two subprovinces would h a r d l y account f o r removal by e r o s i o n of the Huronian sediments to the l a s t remnant. Huronian sediments must have o v e r l a i n a great p o r t i o n of eastern Canada at one time. Rocks at Lake M i s t a s s i n i and the Belcher Islands are probably.Huronian. A s e r i e s of sediments i n Northern Quebec can be c o r r e l a t e d w i t h the Huronian of lake Superior w i t h considerable c e r t a i n t y . Some of these rocks of Huronian age have been i n t r u d e d by g r a n i t e . The absence of Huronian sediments to the east of t h i s l i n e between the G r e n v i l l e and Timiskaming subprovinces can be explained by widespread i n t r u s i o n of a K i l l a r n e y g r a n i t e and l a t e r u p l i f t of the east side and e r o s i o n l e a v i n g only p l u t o n i c l y metamorphosed sediments. PRESENT WORK The present work was c a r r i e d out i n an area that presents a number of advantages. Unlike the areas to the south there I 13 i s present here a g r a n i t e (Algoman) which i s pre-Cobalt. This allows a d i r e c t comparison between the g r a n i t e of the Grenv- i l l e s e r i e s and a g r a n i t e considered Algoman i n the Timisk- aming subprovince. I f the g r a n i t e i n the G r e n v i l l e sub- province i s Algoman i n age i t should be p o s s i b l e to p o i n t out the s i m i l a r i t y . Although the country i s h e a v i l y .wooded and outcrops^ scarce, f r e s h rock cuts along the trans-Canada h i g h - way provide e x c e l l e n t f a c i l i t i e s f o r c l o s e examination. The f i e l d work done was r a t h e r b r i e f , being c a r r i e d out i n two weeks. v I t c o n s i s t e d of a f a i r l y d e t a i l e d examination of the geology and c o l l e c t i o n s of specimens f o r l a b o r a t o r y study along the highway and the Timiskaming and Northern Ontario R a i l r o a d . A traverse of O l i v e , Opechee Bays and Opechee lakes was also-made. FIELD OBSERVATIONS Timiskaming Subprovince. The r e l a t i o n s h i p s between the two subprovinces have been complicated by the presence of f a u l t s of r a t h e r l a r g e d i s - placement. There has been, considerable post-Cobalt movement. The Cobalt s e r i e s everywhere has steep dips and i n some places has been i n t e n s e l y sheared. Otherwise I t i s f r e s h and shows no s i g n of being intruded by g r a n i t e . The g r a n i t e on the Timiskaming side of the subprovince i s at l e a s t of two ages or generations. A l i g h t grey grano- d i o r i t e i s cut by. a p i n k i s h s y e n i t e , ( f i g u r e 1 ) . Both are' coarse grained, contain p l a g i o c l a s e and the mafic mineral appears to be hornblende. There i s a very l i t t l e mafic . 1 4 mineral present in.the pink type. Both types were l a t e r almost everywhere broken i n t o blocks from ten to twenty f e e t to a s i d e . . Movement has taken place s h i f t i n g the blocks about i n a most complicated manner. S l i c k e n s i d e s ,are present on the blocks but.no m i n e r a l i z a t i o n or hydrothermal a l t e r - a t i o n has taken place along the f r a c t u r e s w i t h the exception of some epidote noted at a couple of l o c a l i t i e s along a set of' f r a c t u r e s ' s t r i k i n g N 60° .W. A few t r a p dykes up to f o u r inches wide occur i n some f r a c t u r e s . The pink type of s y e n i t e becomes more p l e n t i f u l to the south east u n t i l f i n a l l y i t completely replaces the grey g r a n o d i o r i t e . Contact Zone The a c t u a l contact between the two subprovinces i s a f a u l t or u s u a l l y a se'ries of steep dipping f a u l t s . The f a u l t s u s u a l l y c o n s i s t of a hundred f e e t or more of h i g h l y sheared g r a n i t e c o n s i s t i n g of quartz eyes i n a micaceous mettrix. The displacement along these f a u l t s has- been considerable judging from the deformation. S l i c k e n s i d e s indicate' an almost v e r t i c a l movement w i t h the east side' moving up r e l a t i v e to the west. Another type of f a u l t which may be c o n s i d e r a b l y younger was observed at Pan Lake.' I t dipped about 40° E and c o n s i s t e d of about four f e e t of loose b r e c c i a t e d m a t e r i a l s i m i l a r to the g r a n i t e gneiss of the hanging and f o o t w a l l s . From the d i s p o s i t i o n of the fragments, movement along- i t ' seemed to be east side up. G r e n v i l l e Subprovince When t h i s f a u l t zone i s crossed at Pan.lake, dark green b i o t i t e gneisses occur to the south-east. They c o n s i s t of a 15 high, p r o p o r t i o n of b i o t i t e imparting a g l i s t e n i n g to cleavage surfaces.;. Quartz seems to. be the only other mineral present. In many places these gneisses have been i n t i m a t e l y i n j e c t e d . by g r a n i t e s t r i n g e r s although g r a n i t e i n the form of dykes or other r e g u l a r shaped bodies i s non-existant. The g r a n i t e occurs i n bodies that pinch and s w e l l , ( f i g u r e 2 ) . The b i o t i t e gneisses give way l o c a l l y to minor bodies of f e l d s p a r gneiss up to 100 f e e t wide and elongated i n the d i r e c t i o n of s t r i k e of the b i o t i t e g n eiss, ( f i g u r e s 3 and 4 ) . A very marked fea t u r e of these' gneisses i s the presence of bedding or banding. The i n t r i c a t e crumpling of t h i s s t r u c t u r e would seem to i n d i c a t e bedding r a t h e r than igneous banding. In a f e l d s p a r gneiss along the highway 300 f e e t south of the O l i v e , S i s k township, boundary i s an i n c l u s i o n which can be d e f i n i t e l y i d e n t i f i e d as a metamorphosed s l a t e cut by minute v e i n l e t s of epidote. This s l a t e contains small f l a t t e n e d , l e n t i c u l a r unconnected masses of g r a n i t e up to s i x inches long which are p a r a l l e l to the s c h i s t o s i t y of the e n c l o s i n g rock. A considerable number of these i n c l u s i o n s were obtained by breaking the e n c l o s i n g rock along the cleavage p l a i n s . In no case were they found to be connected. The nearest exposed g r a n i t i c m a t e r i a l i s over 200 f e e t from t h i s p a r t i c u l a r outcrop. This i n c l u s i o n appears to have been a s l a t e conglomerate s i m i l a r to those of the Cobalt s e r i e s . U n f o r t u n a t e l y t h e . g r a n i t i c pebbles are too h i g h l y crushed to i d e n t i f y the o r i g i n a l texture of the rock or i t s minerals i n t h i n s e c t i o n . 16 These f a c t s would seem to i n d i c a t e these' rocks are paragheisses which have undergone metamorphism at great depth. The general s t r i k e of these rocks i s north-east although the ptygmatic f o l d i n g present leads to considerable v a r i a t i o n . The dips are even more v a r i a b l e than the s t r i k e s but are i n general south-east. The g r a n i t e i n the G r e n v i l l e subprovince i s a b i o t i t e g r a n i t e w i t h v a r y i n g proportions of b i o t i t e , quartz and f e l d - spar. The cleavage faces of the f e l d s p a r have a much b r i g h t e r l u s t e r than those i n the Algoman' g r a n i t e . . Just south of M a r t i n r i v e r on the highway there occurs a l a r g e g r a n i t i c i n t r u s i v e , ; the only one of any s i z e seen i n the G r e n v i l l e area I t has a very marked primary gneis'sosity s t r i k i n g n o r t h - e a s t . I t appears to be a composite i n t r u s i v e ; the north-west margin i s made up c h i e f l y of b i o t i t e o r t hoclase and quartz. The c e n t r a l p o r t i o n i s b i o t i t e g r a n i t e w i t h o r t h o c l a s e c r y s t a l s up to two inches long. A s s o c i a t e d w i t h i t are pegmatite dykes c o n t a i n i n g mica, quartz and orthoclase c r y s t a l s up to three inches i n diameter. f LABORATORY STUDY Algoman I n t r u s i v e s . These are medium grained rocks composed l a r g e l y of p l a g i o c l a s e , hornblende, quartz, and o c c a s i o n a l l y b i o t i t e , potash f e l d s p a r as m i c r o c l i n e and orthoclase was observed i n only one s e c t i o n . Accessory minerals- are z i r c o n , a p a t i t e , p y r i t e , and t i t a n i t e . These rocks although c o n s i d e r a b l y a l t e r e d show no s i g n of deformation. The quartz grains i n some s l i d e s show 17 s t r a i n shadows. The p l a g i o c l a s e i s very u n i f o r m l y a l t e r e d as much as seventy percent ( f i g u r e s 5 and 6) to secondary minerals z o i s i t e , s e r i c i t e , e p i d o t e , and minor c h l o r i t e and carbonate. The hornblende i s almost e n t i r e l y a l t e r e d to magnetite and frayed mats of c h l o r i t e . The b i o t i t e has a l s o a l t e r e d to c h l o r i t e , the asterism of the b i o t i t e remaining i n the c h l o r i t e . The c h i e f compositional v a r i a t i o n s i n these rocks are i n the p r o p o r t i o n of quartz present. Those w i t h a high p r o p o r t i o n of quartz have a p l a g i o c l a s e of composition Ab95 An5 while those w i t h a low quartz content have a higher p r o p o r t i o n of hornblende and the p l a g i o c l a s e i s near Ab60 An40. ; Hence they vary from g r a n o d i o r i t e s to quartz d i o r i t e s . INTRUSIVES IN THE GRENVILLE SUBPROVINCE These rocks show much greater v a r i a t i o n than the Algoman . types although they have strong resemblances which i n d i c a t e they are a l l very c l o s e l y r e l a t e d . The most common minerals . are quartz, potash f e l d s p a r and minor p l a g i o c l a s e . The potash f e l d s p a r occurs most commonly as m i c r o c l i n e , ( f i g u r e 7) The p l a g i o c l a s e i s u s u a l l y a l b i t e around A.b92 An8 v a r y i n g to Ab85 Anl5. In many sections the p l a g i o c l a s e and orthoclase and r a r e l y m i c r o c l i n e c o n t a i n i n c l u s i o n s of muscovite. I n c l u s i o n s of b i o t i t e are sometimes present i n the p l a g i o c l a s e . I t i s s i g n i f i c a n t that a gneiss ( f i g u r e s 3 and 8) formed from the r e c r y s t a l l i z a t i o n of sediments has t h i s same f e a t u r e . o t h e r " e s s e n t i a l B i o t i t e and muscovite are u s u a l l y the only r r > p ^ _ e minerals present and r a r e l y make up more than s i x percent of the rock. P l e o c h r o i c haloes are'common i n the b i o t i t e , o c c u r r i n g most 18 commonly i n the b i o t i t e of the gneisses. They'have diameters up to 0.08 mm. They almost always occur i n pa r t i n g s f o l l o w i n g the cleavage of the b i o t i t e . In the g r a n i t i c rocks they are most common where the rocks have s u f f e r e d dynamic metamorphism. Here, they reach diameters up to 0.06 mm. In one s l i d e the nucleous was d e f i n i t e l y i d e n t i f i e d as z i r c o n . The normal b i o t i t e shows the c h a r a c t e r i s t i c pleochroism l i g h t yellow to ;• dark brown. • Some b i o t i t e has been bleached and i s only s l i g h t s l y p l e o c h r o i c but u n l i k e the above shows high i n t e r f e r e n c e c o l o r s . Around Red Water lake the rocks have s u f f e r e d con- s i d e r a b l e dynamic, metamorphism, and the b i o t i t e has been to some extent a l t e r e d to green b i o t i t e , epidote and c h l o r i t e . Moscovite i s present i n very small f l a k e s u s u a l l y w i t h random o r i e n t a t i o n i n the p l a g i o c l a s e . C l o s e l y a s s o c i a t e d w i t h the b i o t i t e and muscovite i s epidote which appears to have formed as a d e u t e r i c m i n e r a l . The f e l d s p a r s are extremely f r e s h . Where extensive deformation has occurred there i s considerable a l t e r a t i o n to s e r i c i t e , c h l o r i t e , 'with some epidote and carbonate. This a l t e r a t i o n has taken place along minute shear planes. The red c o l o r a t i o n of the potash f e l d s p a r i n hand specimen i s due to hematite as some i s v i s i b l e i n minute cracks and around the margins of the potash f e l d s p a r grains under the microscope. The l a r g e g r a n i t i c i n t r u s i v e mass i n S i s k township ( f i g u r e s 7, 9,) p r e v i o u s l y mentioned has a s l i g h t l y d i f f e r e n t assemblage of minerals. The b i o t i t e present i s dark green i n c o l o r . The amphibole h a s t i n g s i t e i s present. T i t a n i t e o f t e n 19 makes up to f i f t e e n percent of the rock. A very minor amount r • of carbonate i s present "as a primary mineral. Other minerals i d e n t i f i e d are z i r c o n , a p a t i t e , epidote, magnetite, p y r i t e and pyroxene. The few grains of p l a g i o c l a s e present are u s u a l l y a l t e r e d to c h l o r i t e , a yellow powder and s e r i c i t e . The f e l d s p a r i s over seventy f i v e percent potash f e l d s p a r c h i e f l y m i c r o c l i n e . The pyroxene i s a l t e r e d to c h l o r i t e . DIFFERENCES.BETWEEN THE ALGOMAN AND THE GRANITE OF THE GRENVILLE SUBPROVINCE The most s t r i k i n g p e t r o g r a p h i c a l d i f f e r e n c e between the two rock types i s i n the a l t e r a t i o n ( f i g u r e s 5 and-6 show the c h a r a c t e r i s t i c a l t e r a t i o n i n the Algoman i n t r u s i v e s ) . The p l a g i o c l a s e f e l d s p a r of the Algoman i n t r u s i v e s i s u n i f o r m l y and q u i t e h i g h l y a l t e r e d . Comparison w i t h any of the i l l u s t r a t i o n s of the g r a n i t e of the G r e n v i l l e subprovince w i l l i l l u s t r a t e t h i s d i f f e r e n c e . The only extensive a l t e r a t i o n s i n the f e l d s p a r s of the G r e n v i l l e subprovince i n t r u s i v e s i s near zones of d i s l o c a t i o n ; The i n c l u s i o n s i n the f e l d s p a r of these rocks are c h i e f l y muscovite which have•sharp contacts .against the f e l d s p a r . Minor d i f f e r e n c e s are the absence of p l e o c h r o i c haloes i n the b i o t i t e i n the Algoman and t h e i r presence- i n the G r e n v i l l e i n t r u s i v e s . Asterism i s present i n the b i o t i t e of the Algoman while absent i n the G r e n v i l l e i r i t r u s i v e s . I n ' c o n t r a s t to the s t r u c t u r e l e s s A.lgoman the G r e n v i l l e type i n t r u s i v e s u s u a l l y have a primary g n e i s s i c character ( f i g u r e 9 ) . The frequent occurrence of c a t a c l a s t i c textures ( f i g u r e 10). i n the Grenv- 20 i l l e ' t y p e and t h e i r absence i n the Algoman has already been pointed out. COMPOSITIONAL DIFFERENCES I f g r a n i t e s of more than one age are present i n the area compositional d i f f e r e n c e s should be apparent i f they e x i s t . I t i s a w e l l e s t a b l i s h e d f a c t that g r a n i t e i n t r u s i v e s of the Algoman r e v o l u t i o n are extremely low i n potash. Rocks of s i m i l a r types belonging to the K i l l a r n e y r e v o l u t i o n contain considerable potash. Moore and Armstrong (18) have a l s o noted t h i s : "The K i l l a r n e y g r a n i t e shows i n t h i n s e c t i o n that the f e l d s p a r i s mainly orthoclase w i t h a l i t t l e a l b i t e . This i s i n c o n t r a s t to the Algoman g r a n i t e , which contains a much higher p r o p o r t i o n of sodic p l a g i o c l a s e . " Quirke and C o l l i n s (9) page 102 point out, "These gneisses and g r a n i t e , which are termed K i l l a r n e a n , are c h a r a c t e r i z e d throughout the map area by c e r t a i n strong f a m i l y resemblances which f a c i l i t a t e i d e n t i f i c a t i o n . They are notably low i n i r o n oxides, l i m e , and magnesia, and high In a l k a l i s , w i t h soda and potash i n a r a t i o of about 2 to 3. They c o n t a i n a h i g h p r o p o r t i o n of potash f e l d s p a r to p l a g i o - clase and they are red i n c o l o r , varying from pink to deep salmon. The K i l l a r n e a n g r a n i t e s that are i n t r u s i v e i n the Huronian at various places f a r t h e r west along the north shore of lake Huron also posses^these c h a r a c t e r i s t i c s . " The following, t a b l e s (page 22) represent chemical analyses taken from the l i t e r a t u r e and r e c a s t to Rosiwal analyses f o r comparison w i t h Rosiwal analyses (page 23) c a r r i e d out on r e p r e s e n t a t i v e specimens c o l l e c t e d i n the f i e l d by the present w r i t e r . I t can be r e a d i l y seen from a study of the analyses . presented and diagram page 24 that the chemical compositions of the two g r a n i t i c types under study are v e r y " s i m i l a r - 21 to those of the Algoman and K i l l a r n e y g r a n i t e s i n other areas. I n a d d i t i o n to the outstanding d i f f e r e n c e i n the composition of the f e l d s p a r and the l a c k of amphibole i n the G r e n v i l l e i n t r u s i v e s and i t s c o n s i s t e n t occurrence i n the Algoman i t i s worthy of note that the only amphibole i n the G r e n v i l l e specimens s t u d i e d was i n the number 41 specimens from S i s k township. This amphibole i s h a s t i n g s i t e while the only amphibole i n the Algoman i s hornblende. A l s o the G r e n v i l l e i n t r u s i v e s are very much lower i n mafic minerals than the Algoman. A comparison of R o s i w a l l a n a l y s i s made w i l l make t h i s evident. MINERAL COMPOSm-ONSfVOLffilETRT-^ KILLARNEY ALGOMAN A B C D E P G Orthoclase 41.6 28.4 32.3 30.01 30.1 15.9 3.90 A l b i t e 17.1 27.9 23.4 26.1 27.2 30.5 32.2 A n o r t h i t e 1.9 8.53 7.1 6.8 1.52 17.6 5.56 Quartz 34.1 28.3 32.6 32.2 37.9 10.5 37.5 White Mica 1.4 .96 B i o t i t e 4.0 5.63 2.5 4.74 3.3 Magnetite 0.5 T i t a n i t e 0.1 11.8 Hornblende 2.0 25.2 S e r i c i t e 8.07 Tot a l s 100.7 99.8 99.9 99.9 100.0 99.7 v 99.1 A. Analyses 11_ and IV Page 51 Memoir 160, K i l l a r n e y g r a n i t e from K i l l a r n e y Bay, Ontario B. Analyses 111 and V l l Page 51, Memoir 160, Gneiss c l o s e to K i l l a r n e y g r a n i t e i n chara c t e r from K i l l a r n e y , O n t a r i o . C. A n a l y s i s No. VI Page 90, Memoir 160, Greighton g r a n i t e , Snider township. D. A n a l y s i s No. V Page 20 Memoir 160, B i r c h lake g r a n i t e , Hyman township. P. Page 15 Ont. Dept of Mines, V o l . XXX.1V Part 111 1925, McDonald l a k e , South L o r r a i n township. G. Page 11, Ont. Dept of Mines, VolXXXV part 111 1926, James l a k e , Best township ROSIWAL ANALYSES - KILLARNEY ? (volume per cent) ALGOMAN KILLARNEY S107 •410 26 6A 5 6G 48 B. 8 Potash f e l d s p a r 49.2 • 72.2 55.5 65.0 2.8 -- 5.30 • — f 1 M * ° 0 ( f e l d s p a r ) ' , A n o r t h i t e * ^ ' 9.24 5.17 5.52 10.4 34.7 42.0 46.6 65.9 .86 . .49 .78 1.48 21.9 8.8 2.7 7.7 Quartz 35.1 13.6 21.4 21.7 28.6 7.44 24.8 4.3 Hornblende 12.0 31.0 20.0 21.1 B i o t i t e .86 6.84 14.2 9.7 Muscovite, 4.74 A p a t i t e 0.86 1.15 T i t a n i t e and A p a t i t e . 1.9 Garnet and A p a t i t e 1.25 Garnet and B i o t i t e 2.4 Epidote • 2.6 To t a l s . 100.0 100.2 100.0 100.0 100.1 .99.8 '' 100.7 ' 100.2 S107 ̂  Lot 8 Con VI Dana township 41 C Martin lake S i s k township 26 Red Water lake A s k i n township 6 A Askin township 5 A s k i n township 6 C Askin township 486 Law township • .8 Askin township to TKe K«\Uvne^ / ^ | \ »n+o a c j v o ^ p o n H e leff A n d -the. P\\<\otr\<*^ Orve. o r \ -t-hc- v * i < j H t , 5fip a r a k d a> C o n s i d e r a b l e C o i - n p o S , ^ , 0 ' n ^ ' c ^ p ( cvo &SKQ 4-ched). G> is £ 8 - 4 °U p o t ^ s K f e l d s p a v - a, nd 3C-47t> p k ^ . o c l ^ i e f e l d s p f c * " . F i t s J(o % p o t ^ a l , - f e U s p o * - t>nA 4 8 */o p U ^ i o t l , {eld&pav. I 26 RELATIONSHIP BETWEEN THE ALGOMAN AND GRENVILLE INTRUSIVES Microscopic study has shown that a syen i t e (page 13) o r i g i n a l l y b e l i e v e d to be a l a t e r generation of .the Algoman ( f i g u r e 1)• corresponding to one described by Todd (15) to the- north i s r e a l l y a part of the g r a n i t e of the G r e n v i l l e subprovince. The reason f o r t h i s b e l i e f i s that i t corresp- onds to the G r e n v i l l e type I n t r u s i v e s i n petrographic character and composition (see a n a l y s i s 6A page 23). This s i m p l i f i e s the r e l a t i o n s h i p between the two subprovinces i n that the f a u l t i n g (page 14) mentioned i s confined to the G r e n v i l l e subprovince side of the contact l e a v i n g the gran- i t i c types of the G r e n v i l l e i n i n t r u s i v e contact w i t h the Algoman of the Timiskaming subprovince. Along t h i s i n t r u s i v e contact the potash f e l d s p a r s of the G r e n v i l l e type i n t r u s i v e replace the p l a g i o c l a s e f e l d s p a r of the Algoman ( f i g u r e 11). During, t h i s replacement the mi c r o c l i n e expels the a l t e r a t i o n products of the p l a g i o c l a s e and i s f r e e of i n c l u s i o n s except f o r very minor ones, too minute to i d e n t i f y . In another instance of replacement observed m i c r o c l i n e replaced the p l a g i o c l a s e along cleavage d i r e c t i o n s . The p l a g i o c l a s e not replaced during t h i s process appears to undergo r e c r y s t a l l i z a t i o n , becoming f r e s h . I t maintains i t s i n c l u s i o n s but they r e c r y s t a l l i z e . This i s e s p e c i a l l y true of the s e r i c i t e which r e c r y s t a l l i z e s i n t o l a r g e r grains and e x h i b i t s sharp contacts w i t h the host f e l d s p a r . The epidote and z o i s i t e c r y s t a l s seem to r e c r y s t a l - 27 l i z e and d i m i n i s h i n s i z e g i v i n g sharp c r y s t a l boundaries against' the f e l d s p a r . I t i s worthy of note that southeast from the contact between the two subprovinces i n c l u s i o n s i n the f e l d s p a r disappear. .CORRELATION OF THE GRANITE IN THE GRENVILLE WITH THE KILLARNEY GRANITE The g r a n i t e i n the G r e n v i l l e area s t u d i e d has strong resemblance to the northern most rocks mapped as K i l l a r n e y i n Pardo and Dana townships. There seems to be s u f f i c i e n t evidence to c o r r e l a t e them. The composition, absence of amphibole, present of the same type of i n c l u s i o n s i n the p l a g i o c l a s e , p l e o c h r o i c haloes i n the b i o t i t e , p r o t o c l a s t i c and c a t a c l a s t i c textures are i d e n t i c a l . A petrographic d e s c r i p t i o n of the K i l l a r n e y g r a n i t e from Pardo and Dana townships would merely be a r e p e t i t i o n of the d e s c r i p t i o n s already given f o r the gr a n i t e of the G r e n v i l l e subprovince. (Compare f i g u r e s 12 and 13 w i t h the G r e n v i l l e type i n t r u s i v e ) . I t i s a l s o s i g n i f i c a n t that the only amphibole present i n a l l the sections examined was the r a t h e r rare h a s t i n g s i t e . which occurs a l s o i n the Creighton g r a n i t e which i s K i l l a r n e y i n age. This g r a n i t e shows the same mineral assemblage and and c h a r a c t e r i s t i c s as specimens No. 41, from S i s k township. THE pre-TIMISKAMING GRANITE i Although there appears to be s u f f i c i e n t evidence to i n d i c a t e the gr a n i t e of the G r e n v i l l e subprovince i s younger than the Algoman a hasty examination of pre-Timaskaraing g r a n i t i c types was made i n order-to see i f there was any 28 . ' . ' s i m i l a r i t y to the g r a n i t e i n the G r e n v i l l e subprovince. Specimens of t h i s g r a n i t e were"obtained from'the nearest source, .namely Archean (Timiskaming type) conglomerates near H a i l e y - bury. These conglomerates dip about 70° north., They are made up of c l o s e l y packed well-worn e l l i p t i c a l shaped pebbles up to , s i x inches i n leng t h but averaging l e s s than three, embedded i n a f i n e grained a r g i l l a c e o u s matrix. Well over f i f t y per cent of the pebbles are a c i d lavas and l i g h t weathering a c i d i n t r u s i v e rocks. Green ch e r t , i r o n formation, and b a s i c l a v a pebbles are a l s o found. Twelve of the c o l l e c t e d specimens were examined micro- s c o p i c a l l y and were w i t h one exception hypabyssal porphyries. Pheno.crysts of quartz, hornblende, and zoned p l a g i o c l a s e are present i n a f i n e grained groundrnass of quartz and f e l d s p a r . The quartz phenocrysts are u s u a l l y w e l l rounded. The horn- blende phenbcrysts show e x c e l l e n t development of c r y s t a l f a c e s . A l t e r a t i o n of the p l a g i o c l a s e has been c h i e f l y to z o i s i t e ; the hornblende t o . c h l o r i t e and epidote. The p l u t o n i c rock mentioned above i s a coarse grained syenite made up of c l o s e l y k n i t f e l d s p a r c r y s t a l s up to one cm. i n l e n g t h . F i l l i n g minor i n t e s t i c e s between the f e l d s p a r grains and i n larg e grains i s a green mafic m i n e r a l . Under the microscope the rock i s made up c h i e f l y of o l i g o c l a s e and what appears to have been an amphibole'now almost e n t i r e l y a l t e r e d to epidote and c h l o r i t e . The pre Timiskaming g r a n i t i c types are predominantly 29 p o r p h y r i t i c i n h a b i t and possess r a t h e r strong d i f f e r e n c e s to the G r e n v i l l e type i n t r u s i v e s ( f i g u r e 14 and 15). Amphibole i s u s u a l l y present and a l l the f e l d s p a r appears to be p l a g i o c l a s e . CONCLUSIONS From t h i s study i t i s c l e a r that there are two very d i s t i n c t g r a n i t i c types i n the area. Some evidence has been presented to show that one type l y i n g to the south east of the contact between the Timiskaming and G r e n v i l l e subprovinces i s younger than the Algoman g r a n i t e . These two g r a n i t e s can be r e a d i l y d i f f e r e n t i a t e d both i n f i e l d and l a b o r a t o r y work. I t would appear that the A.lgoman g r a n i t e has had a long and complex h i s t o r y before the younger ( G r e n v i l l e ) g r a n i t e o r i g i n a t e d . Evidence f o r t h i s i s seen i n the rat h e r intense a l t e r a t i o n of. the f e l d s p a r s to c h l o r i t e , s e r i c i t e , epidote and z o i s i t e as w e l l as the a l t e r a t i o n of the amphibole. This a l t e r a t i o n i s r e g i o n a l i n character and"has no r e l a t i o n to the i n t r u s i o n of the younger g r a n i t e . There i s some reason-to b e l i e v e that the younger g r a n i t e near the contact w i t h the ol d e r i s made up i n part of a r e c r y s t a l l i z - a t i o n of the o l d e r . The d i s s i m i l a r i t y between pre .Timiskaming g r a n i t e and the younger g r a n i t e has already been pointed out. From a study of e x i s t i n g l i t e r a t u r e i t i s i n t e r e s t i n g to note t h i s younger g r a n i t e i s s i m i l a r to the g r a n i t e through- out the G r e n v i l l e subprovince (4) page 46, (5) pages 11 and 13, (19), (20). 30 Some evidence has. been presented to show the younger . gra n i t e resembles the K i l l a r n e y g r a n i t e i n Pardo and Dana townships. .Further, an uncommon occurrence of the amphibole h a s t i n g s i t e i n a g r a n i t i c mass i n S i s k township i s s i m i l a r to an occurrence i n the Greighton g r a n i t e of K i l l a r n e y age i n Snider township. • I t i s evident a great deal of f a u l t i n g has taken place i n the younger g r a n i t e both from f i e l d examination and widespread c a t a c l a s t i c textures pre'sent. Immediately to the north-west of the contact i n the area under d i s c u s s i o n , the Cobalt s e r i e s i s u n d e r l a i n by Algoman g r a n i t e and not the Keewatin series.' The non-igneous p o r t i o n of rocks i n the G r e n v i l l e subprovince are paragneisses, not metamorphosed l a v a s . 'Since the g r a n i t e of the G r e n v i l l e subprovince i s younger than the Algoman g r a n i t e i t seems most l i k e l y to ex- p l a i n the paragneisses of the G r e n v i l l e subprovince as part of the Cobalt s e r i e s which i s present to the north-west of the contact. There i s at l e a s t some evidence i n t h i s area f o r the po s s i b l e e x t e n t i o n northward of Quirke and C o l l i n s (9) expl a n a t i o n f o r the disappearance of the Huronian. Some supporting evidence f o r t h i s e x p l a n a t i o n has been given by Henderson (21). In the V i l l e - M a r i e and G u i l l e t (Mud) Lake Map-Areas to the north-east of lake Timiskaming he describes two g r a n i t i c rock types. One occupying what i s probably the western extremity of the G r e n v i l l e subprovince i n ' t h a t area i s c h i e f l y made up of m i c r o c l i n e w i t h b i o t i t e and minor amounts 31 of o l i g o c l a s e . To the west of t h i s i s a g r a n i t e w i t h high p l a g i o c l a s e content p o s s i b l y i n d i c a t i n g that the d i f f e r e n c e i n composition of the g r a n i t i c i n t r u s i v e s of the two subprovinces i s maintained northward. Also Norman (22) b e l i e v e s mountain b u i l d i n g took place i n l a t e ^ Precambrian times i n the Chibougami d i s t r i c t of Quebec (page 2 ) . His reasons f o r b e l i e v i n g t h i s are: ( l ) east-west f o l d i n g i n the Keewatin s e r i e s i s truncated by l a t e r north-east f o l d i n g and f a u l t i n g at the contact of the G r e n v i l l e and Timiskaming subprovinces. (2) This f o l d i n g and f a u l t i n g accompanied by mountain b u i l d i n g i s l a t e r than and hence a f f e c t s l a t e pre Cambrian sediments which he b e l i e v e s can be c o r r e l a t e d w i t h the Cobalt s e r i e s . (3) The f a u l t s r e p r e s e n t i n g t h r u s t s from the south- east, have considerable h o r i z o n t a l and v e r t i c a l displacements and are healed by very f r e s h o l i v i n e diabase dykes which i n other areas are the l a t e s t of pre Cambrian rocks. Norman a l s o points out that i f the s t r i k e of these dykes and f a u l t s be p r o j e c t e d southward they i n t e r s e c t lake Huron near K i l l a r n e y bay and hence are along the s t r i k e of f a u l t s de- s c r i b e d by Quirke and C o l l i n s separating the Timiskaming from the G r e n v i l l e subprovince. 32 F i g . 2. Pinch ana s w e l l bodies of g r a n i t e i n the G r e n v i l l e subprovince Olive township x l/40 35 F i g . 3. Feldspar gneiss O l i v e township, t h i n s e c t i o n 33. Hammer and handle t h i r t e e n inches long. F i g . 4. Paragneiss O l i v e township. 34 Figure 6 F i g . 5 and 6. Thin sections 5 and 8 A s k i n township, Algoman showing high p r o p o r t i o n of p l a g i o c l a s e f e l d - spar and i t s c h a r a c t e r i s t i c a l t e r a t i o n . Crossed n i c o l s x 1 2 P i g . 7. Thin s e c t i o n 41C K i l l a r n e y type g r a n i t e , S i s k town- ship showing h i g h p r o p o r t i o n of potash f e l d s p a r ( m i c r o c l i n e ) . Quartz, p l a g i o c l a s e a l t e r e d to c h l o r i t e and t i t a n i t e are the otner minerals. Crossed F i g . 8. Thin s e c t i o n 33, f e l d s p a r g n e i s s , S i s k township showing p l a g i o c l a s e grains w i t h b i o t i t e i n c l u s i o n s Crossed n i c o l s x 12. 36 P i g . 9. Thin s e c t i o n 41C S i s k township showing primary g n e i s s o s i t y . Minerals present are h a s t i n g s i t e (opaoue), b i o t i t e and t i t a n i t e i n a groundmass of quartz ana o r t h o c l a s e . P l a i n l i g h t x 12. G a t a c l a s t i c t e x t u r e , the small l i g h t grains are granulated quartz and f e l d s p a r . Note the s t r a i n shadows i n the quartz and mica i n c l u s i o n s i n the f e l d s p a r . Crossed n i c o l s x 3 5 . P i g . 11. Thin s e c t i o n 7a Ol i v e township, p l a g i o c l a s e grains (algoman) under the cross h a i r s p a r t l y replaced by m i c r o c l i n e of the G r e n v i l l e i n t r u s i v e . Tongues of m i c r o c l i n e p r o j e c t i n t o the p l a g i o c l a s e . Crossed F i g . 12. Thin s e c t i o n S110 K i l l a r n e y g r a n i t e l o t 6, Con. 1 Pardo township, note tne mica i n c l u s i o n s i n the p l a g i o c l a s e and the p l a g i o c l a s e g r a i n broken and healed by mica. Crossed n i c o l s x 35. F i g . 13. Thin s e c t i o n S107 K i l l a r n e y g r a n i t e l o t 8 Con VI i^ana township, showing high p r o p o r t i o n of potash f e l d s p a r ( r a i c r o c l i n e ) and c a t a c l a s t i c t e x t u r e . Crossec n i c o l s x 12. F i g s . 14 and 15. Pre-Tirniskaming porphyry showing phenocrysts of p l a g i o c l a s e hornblende and quartz. Crossed n i c o l s x 12. M i l l e r , W.G., 1. 2. M i l l e r , W.G. and Knight, C y r i l W., • 3. • . . : 4. ' 5. . Baker, M.B., 6. Wilson, M.S., 7. Harding, W.D., 8. Murray, Alexander, 9. Quirke, T.T., and C o l l i n s , W.H.-, 10. Wilson, M.E., 11. Cooke, H.C, .12. P e t t i j o n n , F . J., 13. Gussow, W.C., 14. Barlow, A.E., 40 BIBLIOGRAPHY' Report of the Bureau of Mines, Ontario 1907, Part' 11 The G r e n v i l l e - H a s t i n g s Unconformity, S i x t e e n t h Report of the Ontario Bureau of Mines, 1907. The Laurentian System^ Ontario Bureau of Mines, 1911, Part 1 Pre Cambrian Geology of Southeastern Ontario, Part 1_1, 22nd Report of the Ontario Bureau of Mines, 1913. The Geology of Kingston and V i c i n i t y , Ont. Bureau of Mines, 25th Ann. Rept. 1914, Part 111 Madoc sheet, Map 559 A, Mines and Geol. Branch, Can. Dept Mines and Resources, 1940. Geology of Kaladar and Kennebec Townships, Ont. Dept of Mines. V o l . L I , Part IV, 1942. On the North Coast of Lake Huron, G.S.C. Rept. of Prog; 1847-48, pages 93 - 124. The Disappearance of the Huronian, G.S.C. Memoir 160, 1930. Geology der Erde, Geology of North America, V o l . 1 page 290 - 293, 1939 Some Problems of Sudbury Geology page 6, B u l l e t i n No. 3. G.S.C. 1945. Archean Sedimentation B u l l e t i n of G.S.A. V o l . 54, page 960, 1943. Petrogeny of the Major A c i d I n t r u s - ives of the Rouyn-Bell R i v e r area of Northwestern Quebec. R.C.S. Part IV page 129, 1937. Marginal notes, Geol. Surv. Can. Map. No. 606, 1908. 41 1-5. \Todd, E.W. 16. Bruce, E.L., 17. F a i r b a i r n , .H.W., 18. Moore, E.S., and Armstrong, H.S., 19.. S a t t e r l y , J . , 20. Wright, J.F., • 21. Henderson, J.F., 22. Norman, G.W.Hy, The Matakitchuan Area, Ont. Dept of Mines, V o l . XXXIV, Part 111 1925 Geology of the Townships of Janes, McNish, Pardo and Dana, Ont., Dept of Mines, V o l . XL1, c a r t IV, 1932 Geology of the A s h i g a i n i Lake Area. Ont. D ept of Mines, V o l . XLV111 Part X, 1939. Geology,of the East B u l l Lake Area, Ont. Dept. of Mines, V o l . L l l Part VI , 1943. Min e r a l Occurrences i n Parry Sound D i s t r i c t , Ont. Dept of Mines, V o l . L I , Part 11 1942, Page 11. B r o c k v i l l e , Mallorytown Map Area G.S.C. Memoir 134,: page 28, 1923. Geology and Mi n e r a l Deposits of V i l l e - M a r i e and G u l l l e t (Mud) Lake Map areas, Quebec. Memoir 201, G.S.G. Page 17, 1936. The north-east Trend of Late Pre- Cambrian Tectonic.Features i n the ,Chibougami D i s t r i c t Quebec. R.S.G. Part IV, Page 119, 1936. L I B R A R Y University of British Columbia V a n c o u v e r , C a n a d a 

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