Chapter 2 Review of Hudson Platform Paleozoic Stratigraphy and Biostratigraphy

17 Chapter 2

REVIEW OF HUDSON PLATFORM PALEOZOIC STRATIGRAPHY AND BIOSTRATIGRAPHY A.W.

NORRIS

INTRODUCTION Limits of platform The Hudson P l a t f o r m c o n s i s t s o f t h e e r o s i o n a l remnants o f two adjacent cratonic basins l o c a t e d i n t h e c e n t r a l p a r t o f t h e Canadian S h i e l d where i t encompasses an area o f approximately 970,000 square kilometres. About twot h i r d s o f t h i s area o f Phanerozoic rocks i s covered by water o f Hudson and James Bays (Fig. 2.1). The Hudson P l a t f o r m i s subdivided by a northeast-trending p o s i t i v e area, the Cape H e n r i e t t a Maria Arch, i n t o two Phanerozoic sedimentary basins, t h e Moose R i v e r Basin i n t h e southeast and t h e Hudson Bay Basin i n t h e northwest (Fig. 2.2).

The Paleozoic and Mesozoic succession i n Moose River

Basin includes Ordovician, S i l u r i a n , Devonian, Middle Jurassic and Lower Cretaceous rocks w i t h a composite thickness o f about 760 metres. I n Hudson Bay Basin t h e succession c o n s i s t s o f Ordovician, S i l u r i a n and Devonian rocks which have a t o t a l thickness o f a t l e a s t 1575 metres i n t h e c e n t r a l offshore p a r t o f t h e basin (Fig. 2.3). The Hudson P l a t f o r m i s separated from t h e Michigan and Allegheny Basins t o the south by t h e Fraserdale Arch, from t h e W i l l i s t o n and E l k P o i n t Basins t o t h e southwest by t h e Severn Arch, and from t h e Foxe Basin t o t h e north by t h e B e l l Arch. Nature o f t h e data base Most o f t h e Phanerozoic rock outcrops o f t h e Hudson Bay Lowland are On

confined t o t h e banks o f r i v e r s , and along p a r t s o f t h e coastline.

Southampton, Manse1 and Coats Islands, outcrops are more numerous and occur along the shorelines, r i v e r s and i n t e r i o r upland areas. I n addition, information on Paleozoic rocks can be obtained from over 350 boreholes i n Moose R i v e r Basin (Sanford and Norris, 1975), from 11 boreholes a t t h e southern end o f Hudson Bay Basin, and from 3 o f f s h o r e w e l l s i n c e n t r a l Hudson Bay (Dimian e t al.,

1983).

ORDOVICIAN STRATIGRAPHY The o l d e s t Paleozoic rocks o f t h e Hudson P l a t f o r m are o f l a t e Middle Ordovician (Caradocian) and L a t e Ordovician ( A s h i l l i a n ) age (Fig. 2.4).

18

Figure 2.1. 1973).

Geological provinces of Canada (from Sanford and Norris,

The rock units form narrow outcrop belts along the southwest margin of the Hudson Bay Lowland, i n the Quebec Embayment of Moose River Basin, and on Southampton and Coats Islands a t the north end of Hudson Bay Basin (Fig. 2.5). Maximum thickness of Ordovician s t r a t a v a r i e s from 180 metres i n southern Hudson Bay Basin (Cumming, 1971), t o 83 metres i n Moose River Basin (Sanford e t al., 1968), t o 160 metres on Southampton Island (Heywood and Sanford, 1976).

19 Bad Cache Rapids Group The term Bad Cache Rapids Group was introduced by Nelson (1964) f o r Ordovician s t r a t a o f n o r t h e r n Hudson Bay Lowland t h a t nonconformably o v e r l i e peneplaned Precambrian rocks, and are succeeded unconformably by limestone o f t h e C h u r c h i l l R i v e r Group. I n t h e t y p e area, t h e Bad Cache Rapids Group was d i v i d e d by Nelson i n t o t h e Portage Chute and Surprise Creek formations,

i n ascending sequence.

These are u s e f u l formational

terms i n t h e outcrop b e l t o f t h e t y p e area, b u t are d i f f i c u l t t o apply i n the subsurface, and are seldom used r e g i o n a l l y . The Bad Cache Rapids Group i s recognized throughout t h e Hudson Bay Basin, b u t appears t o t h i n and pinch-out over t h e Cape H e n r i e t t e Maria Arch, and i s n o t recognized i n t h e Moose R i v e r Basin. The thickness o f t h e group varies from 16 t o 30 metres i n t h e Nelson River area, and from 7 1 t o 9 1 metres i n c e n t r a l o f f s h o r e Hudson Bay. On Southampton I s l a n d a thickness of 46 metres i s estimated f o r t h e group. The l i t h o l o g y o f t h e Portage Chute Formation o f t h e Bad Cache Rapids Group i n t h e type area c o n s i s t s o f a basal calcareous q u a r t z sandstone, o v e r l a i n by m i c r o c r y s t a l l i n e dolomite and b i o c l a s t i c limestone commonly e x h i b i t i n g nodular bedding.

The o v e r l y i n g S u r p r i s e Creek Formation

consists o f f i n e l y c r y s t a l l i n e , c h e r t y d o l o m i t i c limestone (Cumming, 1971). On Southampton I s l a n d t h e Bad Cache Rapids Group i s a r e l a t i v e l y uniform l i t h o l o g i c a l sequence o f m i c r i t i c limestone w i t h extensive yellowish-orange m o t t l i n g associated w i t h i n c i p i e n t d o l o m i t i z a t i o n . The basal metre o r so o f beds are g e n e r a l l y sandy and conglomeratic, and anastomosing a l g a l s t r u c t u r e s and laminae and t h i n interbeds o f dark grey shale are comnon i n the lower p a r t o f t h e group (Heywood and Sanford, 1976). The s p o r a d i c a l l y abundant s h e l l y f o s s i l s o f t h e Portage Chute and Surprise Creek formations suggest c o r r e l a t i o n w i t h t h e Dog Head and Cat Head members, r e s p e c t i v e l y , o f t h e Red R i v e r Formation o f southern Manitoba (Nelson and Johnson, 1966).

S h e l l y f o s s i l s o f the Bad Cache Rapids Group

on Southampton I s l a n d suggest a c o r r e l a t i o n w i t h t h e F a r r Formation o f t h e Lake Timiskaming o u t l i e r , and w i t h t h e upper Cobourg beds o f t h e Trenton Group i n south-central and eastern O n t a r i o (Heywood and Sanford, 1976). Conodonts from t h e Bad Cache Rapids Group o f Southampton and Coats Islands are m a i n l y long ranging species t h a t are n o t u s e f u l f o r p r e c i s e c o r r e l a t i o n b u t do i n d i c a t e a l a t e Middle (post-Chazyan) o r e a r l y L a t e Ordovician age (Barnes, 1974). Conodonts from t h e Portage Chute Formation o f northern Manitoba have been placed by Le F'evre e t al. (1976) i n a p r o v i s i o n a l Plectodina furcata Assemblage Zone which they date as Edenian of t h e L a t e Ordovician. Conodonts i n t h e o v e r l y i n g Surprise Creek

20

F i g u r e 2.2. Sedimentary basins o f e a s t - c e n t r a l Canada and a d j a c e n t areas o f U n i t e d S t a t e s (from Sanford and N o r r i s , 1973).

21

Figure 2.3. Schematic basement contour map of the Hudson Platform (from Sanford and Norris, 1973). (bdy = boundary; meta = metamorphic; rx rocks; seds = sedimentary rocks; contours in feet).

22

Formation are placed by Le F'evre e t al. (1976) i n t h e i r Plectodina Loldulata Assemblage Zone which they date as p o s s i b l y M a y s v i l l i a n o f t h e Late Ordovi c i an. Boas R i v e r shale The informal name Boas R i v e r shale was introduced by Heywood and Sanford (1976) t o apply t o d i s t i n c t i v e p e t r o l i f e r o u s shale o v e r l y i n g t h e Bad Cache Rapids Group which was noted a t a s i n g l e l o c a l i t y on t h e upper reaches o f Boas R i v e r on Southampton Island.

The " o i l shale i n t e r v a l " o f Nelson and

Johnson (1966, 1976) on Southampton I s l a n d i s younger than t h e Boas R i v e r shale and i s considered a p a r t o f t h e Red Head Rapids Formation. The Boas R i v e r shale may have had wider d i s t r i b u t i o n i n t h e Hudson Platform, b u t because o f i t s softness i t i s e i t h e r covered by d r i f t o r removed by erosion d u r i n g a mid-Late Ordovician ( M a y s v i l l i a n ) hiatus. T o t a l thickness o f t h e shale a t t h e type s e c t i o n i s unknown because o f s u r f i c i a l deposits, b u t 1.5 t o 2 metres o f beds are exposed. The exposure c o n s i s t s o f black calcareous and p e t r o l i f e r o u s shale, i n uniform beds 0.7 t o 2.5 centimetres t h i c k , weathering l i g h t t o medium g r e y i s h brown. G r a p t o l i t e and t r i l o b i t e species from t h e Boas R i v e r shale are t y p i c a l o f t h e upper Cobourg and Collingwood faunas o f southern O n t a r i o which are o f l a t e Middle o r L a t e Ordovician age.

The conodonts from t h e Boas R i v e r

shale are considered by Barnes (1974) t o be more c l o s e l y r e l a t e d t o t h e o v e r l y i n g C h u r c h i l l R i v e r Group than t o t h e underlying Bad Cache Rapids Group. C h u r c h i l l R i v e r Group The C h u r c h i l l R i v e r Group disconformably o v e r l i e s t h e Bad Cache Rapids Group and i s conformably o v e r l a i n by t h e Red Head Rapids Formation. I n t h e type area i t i s subdivided i n t o t h e Caution Creek and Chasm Creek formations (Nelson, 1964). Rocks o f t h e group occupy a narrow b e l t i n western Hudson Bay Lowland, b u t have been truncated by f a u l t i n g along t h e southern margin o f Moose R i v e r Basin.

They outcrop also on Southampton and Coats I s l a n d s a t t h e

northern end o f Hudson Bay Basin (Fig. 2.5).

On Cape H e n r i e t t a Maria Arch

they overlap t h e Bad Cache Rapids Group t o r e s t d i r e c t l y on Precambrian rocks i n Moose R i v e r Basin. Thickness o f t h e group i s about 90 metres i n southern Hudson Bay Basin (Norford, 1970), about 53 metres on Southampton I s l a n d (Heywood and Sanford, 1976), and between 96 and 114 metres i n o f f s h o r e c e n t r a l Hudson Bay Basin.

23

LEQEND

@

Dolomllo D o l o m i t o : bltumlnoua ~imoatone Llmootono: c h e r t y L bltumlnoua

a

Shale: gray. O r e m L r o d

Shelo: b l a c k nolit. Anhydrltolpypaum

a

Sandatone & conplomarelo

Cryatalllne baaomonl rOCk8

Figure 2.4. Composite Paleozoic lithological successions for the Moose River and Hudson Bay Basins (from Sanford, 1980).

24 I n t h e t y p e area t h e Caution Creek Formation c o n s i s t s o f microc r y s t a l l i n e d o l o m i t i c limestone, with s k e l e t a l fragments c m o n i n some beds. The confdrmably o v e r l y i n g Chasm Creek Formation c o n s i s t s o f r e s i s t a n t , i r o n - r i c h dolomite t o s l i g h t l y d o l o m i t i c limestone, w i t h c m o n t r a c e f o s s i l markings (Nelson and Johnson, 1966). S h e l l y f o s s i l s are abundant i n t h e Caution Creek Formation and l e s s c m o n i n t h e Chasm Creek Formation. Those from t h e Caution Creek Formation suggest a c o r r e l a t i o n w i t h t h e Gunn and lower P e n i t e n t i a r y members; and those from t h e Chasm Creek i n d i c a t e a c o r r e l a t i o n w i t h t h e upper P e n i t e n t i a r y and Gunton members o f t h e Stony Mountain Formation o f southern Manitoba (Nelson and Johnson, 1966). The conodonts from t h e C h u r c h i l l R i v e r Group on Southampton I s l a n d belong t o Fauna 12 o f Sweet e t a l . (1971), and i n d i c a t e a l a t e M a y s v i l l i a n t o Richmondian age (Barnes, 1974; Heywood and Sanford, 1976). The conodonts from t h e Caution Creek and Chasm Creek formations of northern Manitoba are placed by Le F'evre e t al. (1976) i n t h e i r

hrphognathus ordovicicus and Rhipidognathus syrmetricus Assemblage zones, r e s p e c t i v e l y , which they date as Richmondian. Red Head Rapids Formation The name Red Head Rapids Formation was introduced b y Nelson (1964) t o apply t o t h e dolomite and calcareous dolomite t h a t o v e r l i e t h e C h u r c h i l l R i v e r Group, and are succeeded unconformably by limestone o f t h e Severn R i v e r Formation o f S i l u r i a n age i n n o r t h e r n Hudson Bay Lowland. i s recognized i n both basins o f Hudson Platform.

The u n i t

I n t h e Moose R i v e r Basin

i t overlaps t h e C h u r c h i l l R i v e r Group t o r e s t d i r e c t l y on Precambrian

basement rocks. Thickness o f t h e Red Head Rapids Formation i s about 32 metres i n t h e type C h u r c h i l l R i v e r area (Norford, 1970), about 61 metres on Southampton and Coats I s l a n d s (Heywood and Sanford, 1976), and between 88 and 98 metres i n o f f s h o r e c e n t r a l p a r t o f Hudson Bay Basin. I n t h e t y p e C h u r c h i l l R i v e r area, t h e Red Head Rapids Formation was subd i v i d e d by Nelson (1964) i n t o two unnamed members.

The lower member

c o n s i s t s o f orange-weathering m i c r o c r y s t a l l i n e dolomite, i n p l a t y beds between 2.5 and 5 centimetres t h i c k . The upper member c o n s i s t s o f greyweathering s l i g h t l y calcareous dolomite i n beds 2.5 t o 46 centimetres thick.

I n t h e adjacent subsurface, t h e f o r m a t i o n contains i n c l u s i o n s o f

anhydrite and minor t h i n interbeds o f shale (Cumming, 1971).

On Southampton Island, t h r e e d i s t i n c t i v e l i t h o l o g i c a l u n i t s were recognized i n t h e Red Head Rapids Formation, which were i n f o r m a l l y

25

designated as laminated, biostromal, and biohermal beds, i n ascending sequence (Heywood and Sanford, 1976).

The lower u n i t c o n s i s t s o f micro-

c r y s t a l l i n e t o microgranular, laminated limestone and dolomite. The succeeding u n i t i s a massive t o t h i c k bedded, algal, biostromal carbonate c o n s i s t i n g o f vuggy, m i c r o c r y s t a l l i n e , v a r i a b l y dolomitized limestone.

The

uppermost u n i t i s composed o f an i n t e r - r e e f a l f a c i e s o f t h i c k bedded, m i c r o c r y s t a l l i n e limestone; and a biohermal f a c i e s o f a l g a l limestone.

The

l a r g e r bioherms i n t h e l a t t e r f a c i e s are up t o 1.6 k i l o m e t r e s i n diameter and up t o 23 metres i n v e r t i c a l r e l i e f . Vuggy p o r o s i t y i s present i n some of the reefs, and dead o i l i s present i n some o f t h e vugs. Evaporites up t o 20 metres t h i c k i n t h e Red Head Rapids Formation c o n s i s t i n g o f anhydrite near t h e middle and s a l t a t t h e t o p o f t h e formation have been penetrated i n two o f f s h o r e w e l l s i n c e n t r a l Hudson Bay Basin.

Thin sequences o f anhydrite have been encountered a l s o i n several

w e l l s on t h e mainland i n t h e southern p e r i p h e r a l area o f Hudson Bay Basin and i n two w e l l s i n Moose R i v e r Basin. The sparse s h e l l y f o s s i l s i n t h e Red Head Rapids Formation suggest c o r r e l a t i o n w i t h t h e Stonewall Formation o f southern Manitoba (Nelson and Johnson, 1966; Norford, 1970). The few conodonts from the formation have been a l i g n e d by Barnes e t al. (1981) w i t h Fauna 13 o f Gamachian age based on work by McCracken and Barnes (1981) on A n t i c o s t i Island.

Le F h r e e t al. (1976) r e p o r t e d r a r e b u t

l o c a l l y abundant conodonts from t h e lower p a r t o f t h e formation and these were assigned t o t h e i r Rhipidognathus syrmetricus Assemblage Zone. SILURIAN STRATIGRAPHY S i l u r i a n rocks are widely d i s t r i b u t e d i n t h e Hudson P l a t f o r m (Fig. 2.5). They are separated from underlying Ordovician rocks by a h i a t u s o f some magnitude, which includes a p a r t o f t h e Gamachian o f t h e Ordovician and a l l o f t h e Lower Llandovery o f t h e S i l u r i a n .

The aggregate thickness o f t h e

S i l u r i a n i s about 300 metres i n Moose R i v e r Basin; about 620 metres i n the c e n t r a l o f f s h o r e p a r t o f Hudson Bay Basin; and about 300 metres f o r t h e incomplete succession on Southampton Island. Severn R i v e r Formation The name Severn R i v e r Formation was introduced b y Savage and Van Tuyl (1919) and applies t o basal S i l u r i a n beds t h a t unconformably o v e r l i e s s t r a t a o f t h e Ordovician Red Head Rapids Formation and are, i n turn, conformably succeeded by s t r a t a o f t h e Ekwan R i v e r Formation.

26

F i g u r e 2.5. Generalized g e o l o g i c a l map o f t h e Hudson P l a t f o r m (from Sanford and Norris, 1973). The area depicted as Cretaceous i s now known t o have a more l i m i t e d d i s t r i b u t i o n and includes Middle Jurassic beds. I n l o c a l areas i n both basins, Severn R i v e r s t r a t a overlap t h e Ordovician t o r e s t nonconformably on Precambrian h i g h basement rocks. Recorded thicknesses o f t h e Severn R i v e r Formation vary from a maximum o f 248 metres i n t h e c e n t r a l o f f s h o r e p a r t o f Hudson Bay Basin t o a minimum o f 45 metres i n t h e subsurface o f n o r t h e r n Moose R i v e r Basin.

27 In the outcrop belt of northern Hudson Bay Lowland the Severn River Formation consists of a heterogenous assemblage of limestone, dolomitic limestone, and dolomite (Norford, 1971). Some of the beds are burrowed and mottled, others contain evenly and irregularly layered structures of presumed algal origin, and flat pebble conglomerates. Basal beds of the formation are commonly sandy and conglomeratic where they overlap Precambrian basement rocks. On Southampton Island, the Severn River Formation consists mainly of microcrystalline limestone and dolomite with yellowish-orange mottling (Heywood and Sanford, 1976). Fragmental skeletal limestone and 1 imestone with varying amounts of algal structures are also present, the latter producing irregular and wavy bedding surfaces. Shelly fossils from the Severn River Formation in the subsurface of northern Hudson Bay Lowland were assigned by Norford (1970) to three informal faunal divisions designated as 0, E and F, in ascending sequence. Faunal division D occurs in the lower third of the formation and is characterized by the distinctive brachiopod Virgiana decussata (Whiteaves) which is dated as Middle Llandovery. Faunal division E is from the middle third of the formation and contains elements of the Cannrotoechia cf. C. winiskensis Whiteaves Zone of Berry and Boucot (1970) which is dated as early Late Llandovery. Faunal division F occurs in the upper third of the formation and contains Pteroleperditia and 7Glassia cf. ?G. variabilis Whiteaves amongst other forms, but does not contain P e n t a r u s . It is dated as early Late Llandovery. From the subsurface of northern Hudson Bay Lowland, Le F’evre et al. (1976) recognized three provisional conodont assemblage zones in the Severn River Formation as follows in ascending sequence: Spathognathodus elibatus dated as Middle Llandovery; Ozarkodina n. sp. A and B of Pollock, Rexroad and Nicoll (1970) dated as late Middle and early Late Llandovery; and Neospathognathodus n. sp. + “Neurodont“ hyaline forms dated as mid Late Llandovery in age. Ekwan River Formation The name Ekwan River Formation was introduced by Savage and Van Tuyl (1919), and is now applied to strata that conformably succeed the Severn River Formation and are, in turn, conformably overlain by reefal and associated carbonates of the Attawapiskat Formation. In areas where the reef-bearing Attawapiskat Formation is not developed, the Ekwan River is succeeded by the lower member of the Kenogami River Formation.

28

P a r t s o f t h e Ekwan R i v e r Formation are w e l l exposed along some o f t h e r i v e r s c u t t i n g across t h e Moose R i v e r Basin o f t h e southern Hudson Bay Lowland, b u t fewer exposures occur i n t h e n o r t h e r n lowland.

The formation

i s widely d i s t r i b u t e d on Southampton, Mansel and Coats Islands. Representative thicknesses o f t h e formation are as f o l l o w s : 40 metres i n northern Hudson Bay Lowland; up t o 235 metres i n t h e o f f s h o r e c e n t r a l p a r t o f Hudson Bay Basin; and up t o 90 metres (estimated) on i s l a n d s t o t h e north. Rocks o f t h e Ekwan R i v e r Formation i n Hudson Bay Lowland c o n s i s t o f w e l l bedded, s k e l e t a l and p e l l e t o i d a l limestone and f i n e l y c r y s t a l l i n e dolomite t h a t l o c a l l y swell i n t o i r r e g u l a r massive biostromal lenses. Varying amounts o f d e t r i t a l carbonate and s k e l e t a l fragments form a h i g h percentage o f t h e sequence i n some places.

Nodular c h e r t i s a l s o c m o n .

On Southampton, Coats and Mansel Islands, t h e Ekwan R i v e r Formation i s d i v i s i b l e i n t o t h r e e rock u n i t s (Heywood and Sanford, 1976).

The lower u n i t i s composed o f limestone t h a t l o c a l l y c o n t a i n columnar s t r o m a t o l i t i c

zones up t o 9 metres t h i c k .

L a t e r a l l y equivalent s t r a t a c o n s i s t o f laminated limestone w i t h s c a t t e r e d interbeds o f f l a t pebble conglomerate.

The middle u n i t c o n s i s t s o f r e s i s t a n t , planar t o l e n t i c u l a r bedded limestone. I t contains s t r o m a t o l i t e , stromatoporoid o r c o r a l biostromes, and c h e r t nodules are l o c a l l y abundant. The upper u n i t i s a t h i c k l y bedded sequence o f f i n e - t o medium-grained c r i n o i d a l limestone and dolomite. The Ekwan R i v e r Formation contains abundant and d i v e r s e s h e l l y f o s s i l s i n c l u d i n g stromatopoids,

corals, brachiopods and cephalopods.

Faunal

d i v i s i o n G o f Norford (1970) occupies a t h i n i n t e r v a l i n t h e lower p a r t o f t h e formation i n northern Hudson Bay Lowland.

I t i s c h a r c t e r i z e d by t h e

ostracode Dihogmchi 1ina latirmrginata (Jones) and t h e brachiopod Pentamerus sp., dated as L a t e Llandovery. Faunal d i v i s i o n H occurs i n t h e upper three-quarters o f t h e formation and includes a c o r a l fauna and t h e brachiopod Pentcmerus sp. i n d i c a t i n g a Late Llandovery age. Conodonts o f t h e Pterospathodus celloni Zone o f Late b u t n o t l a t e s t Llandovery age have been i d e n t i f i e d from outcrops o f t h e Ekwan R i v e r Formation along t h e Severn and Attawapiskat r i v e r s (Norford, 1981). Conodonts from core o f t h e formation i n n o r t h e r n Manitoba are assigned by Le F'evre e t al. (1976) t o t h e lower p a r t o f t h e celloni Zone. A t t awapi skat Format ion The name Attawapiskat Formation (Savage and Van Tuyl, 1919) a p p l i e s t o t h e assemblage o f r e e f a l and associated carbonates t h a t o v e r l i e t h e Ekwan R i v e r Formation and are, i n turn, o v e r l a i n by t h e lower member o f t h e

29 Kenogami R i v e r Formation.

These r e e f a l carbonates appear t o incompletely

surround and cover t h e f l a n k s o f t h e Moose R i v e r and Hudson B a y basins.

In

outcrops they are most f u l l y developed on t h e northwestern and southeastern f l a n k s o f t h e Cape H e n r i e t t a Arch, and on t h e southern f l a n k of t h e B e l l Arch. The r e e f a l carbonates are i n p a r t l a t e r a l l y equivalent t o t h e upper p a r t o f t h e Ekwan R i v e r Formation. The thickness o f t h e Attwapiskat Formation v a r i e s from 62 metres i n northern Hudson Bay Lowland, t o 53 metres (estimated) on Southampton, Coats and Manse1 Islands. Two predominant l i t h o f a c i e s , r e e f and inter-reef, formation.

.are present i n t h e

The most conspicuous i n t h e outcrop b e l t s are t h e swarms o f

bioherms t h a t are scores o f metres wide and up t o 10 metres high. These consist o f v a r i a b l y t e x t u r e d limestone, commonly m i c r o c r y s t a l l i n e , and comnonly fragmental throughout.

Organic remains w i t h i n t h e bioherms appear

t o c o n s i s t m a i n l y o f calcareous algae, bulbous stromatoporoids, and f a v o s i t i d and h a l y s i t i d corals.

Coarse vugs are l o c a l l y present w i t h i n t h e

bioherms.

The i n t e r - r e e f a l f a c i e s i s more u n i f o r m l y bedded and appears t o o v e r l i e and f l a n k t h e reefs. I t c o n s i s t s g e n e r a l l y o f l i m e mudstone and dolomite w i t h numerous coarse, granular t e x t u r e d d e t r i t a l beds, c m o n l y w i t h e x c e l l e n t i n t e r g r a n u l a r and p i n p o i n t porosity. Concentric f l a n k i n g beds o f fragmental carbonate beds show d e p o s i t i o n a l d i p s as h i g h as t h i r t y degrees. S h e l l y f o s s i l s from t h i s formation i n t h e subsurface o f northern Manitoba are assigned by N o r f o r d (1970) t o h i s faunal d i v i s i o n I. B i o s t r a t i g r a p h i c a l l y u s e f u l genera include Palaeocyclus, Solenohalysites and Pentamroides, which i n d i c a t e a l a t e s t Llandovery o r e a r l y Wenlock age. The few conodonts from t h e lower h a l f of t h e formation are assigned by Le F’evre e t al. (1976) t o t h e upper p a r t of t h e Pterospathodus celloni Zone o f L a t e Llandovery age.

Above t h i s , conodonts i n a t h i n i n t e r v a l are

assigned t o a Neospathognathodus n. sp. Assemblage Zone, b u t a t h i c k e r i n t e r v a l a t t h e t o p o f t h e formation i s barren o f conodonts. SILURIAN-DEVONIAN STRATIGRAPHY Kenogami R i v e r Formation The term Kenogami River Formation was introduced by Dyer (1930) f o r t h e sparsely f o s s i l i f e r w s sequence o f shale and dolomite exposed along t h e Kenogami, Pagwachuan and Albany r i v e r s i n Moose River Basin.

This formation

o v e r l i e s t h e Attawapiskat Formation, and t h e Ekwan R i v e r Formation i n places where t h e Attawapiskat i s n o t developed, and i s succeeded by the Lower Devonian Stooping R i v e r Formation. Locally, as i n southern Moose

30

River Basin, the Kenogami River i s overlain by clastic continental beds of the Lower Devonian Sextant Formation. In other areas in both basins, Kenogami River strata have been uplifted by block faulting and removed by erosion (Fig. 2.6).

SOUTHAMPTON PLAIN

L%~-'+HUDSON

BAY+HUDSON

BAY BASIN +MOOSE

+HUDSON

BAY LOWLAND+

R.

BASIN^

m

500L 0

0

km 150

GSC

Figure 2.6. Schematic north-south cross-section of the Hudson Platform (from Sanford and Norris, 1973). (See Fig. 2.5 for Legend). Three major lithological units are recognized in the Kenogami River Formation which are informally designated as lower, middle and upper members (Sanford and Norris, 1975). Recently, Tillement et al. (1976) introduced the name Hudson Formation to apply to beds here included in the Kenogami River Formation in a well located in east-central Hudson Bay. The name is considered invalid because the lithology and a seismic profile across Hudson Bay strongly support the contention that the interval in question is a part of the Kenogami River Format i on. In Moose River Basin, the thickness of the lower member varies from 23 to 53 metres; the middle member from 145 to 168 metres; and the upper member from 11 to 5'3 metres (Sanford et al., 1968). In a well at the southern end of Hudson Bay Basin, the three members are 36, 158 and 8 metres thick, respectively. The lower member consists of a uniform sequence of microcrystalline dolomite. The middle member succeeds the lower member gradationally and

31 consists of gypsiferous, and in part mottled mudstone, siltstone, sandstone, minor argillaceous dolomite, and coarsely vuggy limestone. The upper member consists of fine to microcrystalline dolomite. In Moose River Basin the lower member contains thin interbeds of anhydrite, and the upper member contains a brecciated zone near the top, which probably resulted from salt leaching. I n Hudson Bay Basin, a salt unit occurs in the lower member, and a second salt occurs near the top of the middle member. The few shelly fossils from the Kenogami River Formation are from the upper member and these are poorly preserved and not diagnostic. Spores described by McGregor and Camfield (1976) from two wells in the Moose River Basin indicate a Late Silurian (?Downtonian) or Early Devonian age for the upper part of the middle member, and an Early Devonian (Gedinnian and Siegenian) age for the upper member. The Silurian-Devonian boundary has not been determined but is probably within the middle member of the formation. DEVONIAN STRATIGRAPHY The Devonian succession in Hudson Platform consists of the following rock units in ascending sequence: upper member of the Kenogami River Formation, and Sextant, Stooping River, Kwataboahegan, Moose River, Murray Island, Williams Island and Long Rapids formations. In Moose River Basin this succession occupies the central part o f the basin and is partly covered by Mesozoic rocks (Fig. 2.5). In Hudson Bay Basin only a small part of the succession is present along the mainland in the Cape Tatnam area, east of Nelson River delta, and the remainder is offshore covered by water of Hudson Bay. The composite thickness in Moose River Basin is about 400 metres; and in Hudson Bay Basin it is about 570 metres. Sextant Format i on The name Sextant sandstone and shale was introduced by Savage and Van Tuyl (1919) for the beds exposed along Abitibi River in the vicinity of Sextant Rapids. The name Sextant Formation is now applied to the wedge of continental clastic beds that borders the southern margin of Moose River Basin and are overlapped by and merge northward into marine carbonate beds of the Stooping River Formation. From a maximum thickness of about 45 metres near the southern margin of the basin, the formation thins northward to a feather edge as the continental beds are overlapped and abruptly replaced by marine carbonate. The Sextant Formation consists o f nonmarine shale, clay, siltstone, sandstone and conglomerate, with friable arkosic sandstone as the

32 cinnnonest component.

These rocks occur as t h i n t o medium l e n s i n g beds w i t h

coarser components being c m o n l y crossbedded. P l a n t remains have been recovered from scattered beds o f t h e formation, p a r t i c u l a r l y from lenses o f micaceous shale, and these have been noted and studied by various workers i n c l u d i n g Martison (1953), Hueber (1983).

Lemon (1953),

and

On t h e b a s i s o f t h e plants, t h e Sextant Formation was dated

as E a r l y Devonian. Spores from t h e formation i n d i c a t e a mid t o l a t e Emsian ( l a t e E a r l y Devonian) age (McGregor e t al.,

1970; McGregor and Camfield, 1976).

Stooping R i v e r Formation The Stooping R i v e r Formation comprises Lower Devonian limestone and dolomite t h a t normally succeed t h e Kenogami R i v e r Formation (Sanford e t al.,

1968).

However, where t h e l a t t e r and o l d e r Paleozoic rocks have

been u p l i f t e d and p a r t i a l l y o r completely removed by erosion, t h e Stooping R i v e r o r i t s i n p a r t nonmarine equivalent (Sextant Formation) may r e s t on o l d e r S i l u r i a n , Ordovician, o r Precambrian basement rocks. The Stooping R i v e r i n both basins i s o v e r l a i n by carbonate o f t h e Kwataboahegan Format ion. Representative thicknesses o f t h e formation i n t h e subsurface o f Moose R i v e r Basin vary from a maximum o f 143 t o a minimum o f 12 metres. Thicknesses o f t h e formation i n t h e subsurface o f southern Hudson Bay Basin vary from 78 t o 86 metres. The Stooping R i v e r Formation i n Moose R i v e r Basin c o n s i s t s o f nodular, t h i n bedded, f i n e l y c r y s t a l l i n e and l o c a l l y d e t r i t a l , c h e r t y limestone and dolomite.

Where these beds overlap t h e c l a s t i c tongue o f t h e Sextant

Formation i n t h e southern p a r t o f t h e basin, t h e basal beds are sandy and dolomitic.

I n t h e subsurface o f t h e onshore southern p a r t o f Hudson Bay

Basin t h e carbonate beds are f r e e o f chert, b u t instead c o n t a i n minor lenses o f anhydrite. Traced o f f s h o r e i n t o t h e c e n t r a l p a r t o f t h e Hudson Bay Basin, t h e e v a p o r i t i c carbonate changes t o a u n i t c o n s i s t i n g l a r g e l y o f ha1ite. F o s s i l s i n t h e Stooping R i v e r Formation o f Moose R i v e r Basin are moderately abundant and diverse.

Amongst t h e brachiopods are many elements

t h a t occur t y p i c a l l y i n t h e Schoharie and Bois Blanc and equivalent format i o n s o f eastern N o r t h America which are dated as Emsian (Sanford and N o r r i s , 1975). Conodonts from the upper t w o - t h i r d s o f t h e formation range i n age from mid t o l a t e Emsian (Sanford and Norris, 1975). Spores from t h e lower t w o - t h i r d s o f t h e formation are assigned by McGregor and Camfield (1976) t o t h e caperatus-miensis Assemblage Zone dated as p o s s i b l y

33

Siegenian a t t h e base t o mid-Emsian a t t h e top.

Spores from the uppermost

t h i r d o f t h e formation are assigned t o t h e lower p a r t o f t h e annulatusl i n d l a r e n s i s Assemblage Zone dated as l a t e Emsian. Kwataboahegan Formation The Kwataboahegan Formation applies t o r e s i s t a n t , t h i c k bedded c o r a l limestone t h a t i s w e l l exposed along t h e lower reaches o f Kwataboahegan River (Sanford e t al.,

1968).

The contact w i t h t h e u n d e r l y i n g Stooping

River Formation i s g e n e r a l l y conformable, b u t i n southeastern Moose R i v e r Basin where u n d e r l y i n g rock u n i t s have been a f f e c t e d b y block f a u l t i n g , t h e contact i s disconformable.

I n both basins t h e Kwataboahegan i s conformably

o v e r l a i n by e v a p o r i t i c and carbonate beds o f t h e Moose R i v e r Formation. Representative thicknesses o f t h e formation i n Moose R i v e r Basin vary from 24 t o 77 metres; and recorded thicknesses i n Hudson Bay Basin vary from 39 t o about 70 metres.

The Kwataboahegan Formation i n Moose R i v e r Basin c o n s i s t s mainly o f r e s i s t a n t , t h i c k bedded t o massive, medium grained, biostromal limestone w i t h abundant stromatoporoids and corals.

Angular c l a s t s o f quartz and

feldspar are present i n basal beds i n t h e southern p a r t o f t h e basin.

The

biostromal carbonate buildups appear t o be associated w i t h topographic highs caused by Precambrian knobs p r o j e c t i n g through Phanerozoic sediments. Away from t h e Precambrian knobs t h e sequence i s t h i n n e r bedded, h i g h l y bituminous, and g e n e r a l l y l e s s f o s s i l i f e r o u s .

I n t h e southern p a r t o f

Hudson Bay Basin, interbeds o f a r g i l l a c e o u s limestone are a l s o present. The Kwataboahegan Formation i s by f a r t h e most abundantly f o s s i l i f e r o u s u n i t o f t h e Devonian succession i n Hudson P l a t f o r m which i s dominated by corals, stromatoporoids and brachiopods.

According t o O l i v e r ( i Sanford ~

and Norris, 1975), t h e c o r a l s are a mixed assemblage w i t h most o f t h e forms i n d i c a t i n g a Schoharie-Bois Blanc (Emsian) age, and others i n d i c a t i n g a younger ( l a t e Emsian t o E i f e l i a n ) Onondaga age.

The presence of-igenia

amongst t h e brachiopods suggests an alignment w i t h t h e upper p a r t of Dutro's (1981) Arrphigenia Assemblage Zone o f New York State. The conodonts from t h e lower t h i r d o f t h e formation are s i m i l a r t o those from t h e E d g e c l i f f Member o f t h e Onondaga Limestone o f New York dated as l a t e Emsian (Uyeno e t al.,

1982).

Spores from t h e Kwataboahegan Formation are assigned

by McGregor and Camfield (1976) t o t h e upper p a r t o f t h e annulatusl i n d l a r e n s i s and lower p a r t o f t h e v e l a t a - l a n g i i Assemblage zones, dated as l a t e Emsian and e a r l y E i f e l i a n , r e s p e c t i v e l y .

34

Moose River Formation The Moose River Formation applies to unfossiliferous, generally brecciated limestone and associated gypsum beds in Moose River Basin (Dyer, 1928). It overlies the Kwataboahegan Formation, and is, in turn, succeeded by limestone of the Murray Island Formation (Sanford et al., 1968). The Moose River Formation is present also in Hudson Bay Basin where it has been penetrated by a number of drill holes. In Moose River Basin the maximum recorded thickness is 89 metres where the sequence is unbrecciated and where there is little or no removal of evaporites by solution. In central Hudson Bay Basin the maximum thickness is about 160 metres. I n the central part of Moose River Basin the formation consists mainly of gypsum occurring between thin carbonate units of limestone and/or dolomite at the base and top of the formation. Thin shale beds occur at scattered intervals within the sequence. Carbonate breccias of collapse origin are c m o n in outcrops in the southern part of the basin where the evaporites have been dissolved. In the central part of Hudson Bay Basin the formation consists o f a lower unit of halite, succeeded by a thick sequence of interbedded carbonate and red shale. Fossils are exceedingly scarce in the Moose River Formation because of the restricted marine environment. On the basis of stratigraphic position and the few spores recorded by McGregor and Camfield (1976), the Moose River Formation is dated as late but not latest Eifelian of the Middle Devonian. Murray Island Formation The Murray Island Formation applies to a relatively thin sequence of fossiliferous limestone that disconformably overlies the Moose River Formation, and is overlain by shale and limestone of the Williams Island Formation (Sanford et al., 1968). Outcrops of the formation are limited to the southeastern part of Moose River Basin. Thicknesses of the formation in the subsurface of Moose River Basin vary from 6 to 20 metres. In the central part o f Hudson Bay Basin it thickens to a maximum of 53 metres. In the type area the Murray Island Formation consists of a resistant, cliff-forming succession of banded, bituminous, highly calcareous dolomite, fine to very coarse grained clastic limestone, and thin to medium bedded argi 1 laceous 1 imestone. The carbonate beds are generally jointed and fractured, and in places slightly brecciated, resulting from solution and subsidence of underlying evaporitic Moose River beds. The basal beds o f

35

the formation comnonly contain rounded carbonate pebbles derived from the underlying Moose River Formation, suggesting that they rest on an erosional surface. In the subsurface of central Hudson Bay Basin the Murray Island Formation consists of fine to medium grained, clastic limestone, associated with argi 1 1 aceous 1 imestone. Shelly fossils are not abundant but include a diverse assemblage of brachiopods, including elements from the Appalachian, Mid-continent and Cordilleran Faunal Provinces. The highest occurrence of Pnphigenia cf. A. elongata (Vanuxem) in the Hudson Bay Lowland is within the Murray Island Formation. This is a typical Appalachian element which in New York ranges up into the Moorehouse Member of the Onondaga Limestone below the Tioga Bentonite. Mid-continent elements which include Spinatrypa costata (Bassett) and Spinatrypa ehlersi (Bassett) which occur typically in the Dundee Limestone of southeastern Michigan (Bassett, 1935). A Cordilleran element, Desquamtia arctica (Warren), occurs also in the lower Rogers City Formation of Michigan, Elm Point Formation of southern Manitoba, lower Methy Formation of northern Saskatchewan and northeastern Alberta, as we1 1 as in many equivalent rock units in northwestern Canada. Conodonts in the Murray Island Formation indicate a late Eifelian age (Sanford and Norris, 1975). Spores in formations imnediately underlying and overlying the Murray Island Formation are placed by McGregor and Camfield (1976) in their devonicus-orcadens is Assemblage Zone.

Wi 1 1 i ams Island Formati on The name Williams Island Formation was introduced by Kindle (1924) to apply to a succession of shale and carbonate exposed on Williams Island and adjacent banks o f Abitibi River near the downstream end of Long Rapids. As currently defined, the name applies to the beds disconformably overlying limestone of the Murray Island Formation, and disconformably underlying shale of the Long Rapids Formation. Throughout the Moose River Basin, the Williams Island Formation consists of a lower, recessive shale member, and an upper, resistant carbonate member. In Moose River Basin, the thickness of the lower member varies from 36 to 47 metres, and the upper member from 33 to 45 metres. In the offshore central part of Hudson Bay Basin, the thickness of the formation is about 177 metres. The lower member of the formation exposed on Mike Island, Moose River, consists of soft grey shale, irregularly bedded soft sandstone, gypsiferous

36 sandy shale, gypsiferous s i l t s t o n e and sandstone, s o f t limestone, and some brecciated limestone. A t several other l o c a l i t i e s i n t h e Moose R i v e r Basin the exposed basal beds o f t h e formation c o n s i s t o f r i c h l y f o s s i l i f e r o u s b r i c k - r e d calcareous shale. The upper member o f t h e formation exposed on and near Williams Island, A b i t i b i River, c o n s i s t s o f t h i n t o medium bedded a r g i l l a c e o u s limestone and calcareous shale; medium t o coarse grained saccharoidal and o o l i t i c limestone; p l a t y , a r g i l l a c e o u s limestone; and p a r t l y brecciated, vuggy, o o l i t i c limestone. The brachiopods and c o r a l s from t h e lower shaly member o f t h e formation i n Moose R i v e r Basin are i d e n t i c a l o r c l o s e l y s i m i l a r t o forms o c c u r r i n g i n t h e Hamilton Group o f southwestern O n t a r i o and New York S t a t e dated as G i v e t i a n o f t h e l a t e Middle Devonian. F o s s i l s i n r e d calcareous c l a y dredged from t h e southern end of t h e Mid-Bay Shoal i n Hudson Bay (57O4O8N, 85'17'W) are c l o s e l y s i m i l a r t o species i n t h e Traverse Group o f n o r t h e r n Michigan (Sanford and Norris, 1975). A fauna c o n s i s t i n g l a r g e l y o f c o r a l s from t h e upper member o f t h e type

s e c t i o n o f t h e formation contains many elements i n common w i t h t h e Traverse Group o f Michigan dated as Givetian, l a t e Middle Devonian ( F r i t z , Lemon and Norris, 1957). Numerous and d i v e r s e brachiopods were r e c e n t l y c o l l e c t e d from a green clay-shale bed about 1 metre t h i c k a t t h e t o p o f t h e formation exposed on A b i t i b i R i v e r near Williams Island.

Two o f t h e more d i a g n o s t i c brachiopods

i n t h i s assemblage are c f . Leiorhynchus quadracostatus (Vanuxem) and

Ladogioides par McLaren. The former species occurs t y p i c a l l y i n t h e upper Geneseo Shale and lower Sherburne Sandstone o f New York (Sanford and Norris, 1975). These u n i t s are a l i g n e d w i t h t h e conodont Lowermost asyrmetricus Zone o f l a t e s t Givetian, l a t e Middle Devonian age (Klapper, 1981; O l i v e r and Klapper, 1981). Ladogioides pax occurs t y p i c a l l y i n t h e lower Waterways Formation of n o r t h e r n A l b e r t a and i n e q u i v a l e n t beds i n t h e southern D i s t r i c t o f Mackenzie (McLaren, 1962), where i t i s associated w i t h conodonts o f t h e Lowermost asyrmetricus Zone ( N o r r i s and Uyeno, 1983). Spores from t h e lower p a r t o f t h e formation i n Moose R i v e r Basin are assigned t o t h e devonicus-orcadensis Assemblage Zone dated as e a r l y t o middle G i v e t i a n (McGregor and Camfield, 1976). Long Rapids Formation The name Long Rapids Shale was a p p l i e d t o t h e Upper Devonian shale exposed along A b i t i b i R i v e r i n t h e v i c i n i t y o f Long Rapids (Savage and Van Tuyl, 1919).

These beds disconformably o v e r l i e t h e upper carbonate

37 member of the Williams Island Formation, and are unconformably overlain by continental beds of Mesozoic age in Moose River Basin. Thickness of this formation in Moose River Basin is generally less than 30 metres, but it reaches a maximum of 87 metres in the Onakawana area where less erosion has occurred at the top of the sequence. Thickness of beds assigned to the Long Rapids Formation in central Hudson Bay is about 150 metres (Sanford and Norris, 1975). The Long Rapids Formation in Moose River Basin consists mainly of dafik shale, some mudstone, minor thin beds of limestone and dolomite, and some clay ironstone concretions. Beds tentatively assigned 'to the Long Rapids Formation in Hudson Bay Basin are conspicuously different from those in Moose River Basin. They consist of red, pink, and salt and pepper grey, evaporitic mudstone, shale, siltstone and sandstone. The large sporomorph, T a m n i t e s huronensis (Dawson), is the only relatively cannon fossil in the dark shale of the Long Rapids Formation of Moose River Basin. The few other fossils recorded from the formation include tentaculitids, brachiopods, amnonoids, and fragments of fish plates and plant tissue. Manticoceras cf. M. sinuosun (Hall) from a thin limestone bed at or near the base of the formation outcropping on Abitibi River (Miller, 1938), is a goniatite species that occurs in the Cashaqua Shale of the Sonyea Group of New York (Kirchgasser and House, 1981). Most of the Cashaqua Shale, according to Klapper (1981), is assigned to the conodont Ancyrognathus triangularis Zone of mid Frasnian, early Late Devonian age. Recently, several specimens of a brachiopod suggestive of Calvinaria vnriabi 1 is athabascensis (Kindle) were collected from a thin carbonate bed at the same locality but several metres above the goniatite bed on Abitibi River near Williams Island. This subspecies is widely distributed in western Canada where it occurs in the upper Maligne and lower Perdrix and Cooking Lake formations, and in the Escarpment Member of the Hay River Formation (McLaren, 1962). Unfortunately, none of the occurrences in western Canada is as yet tied in with precise conodont datings. However, its relationship to the goniatite bed suggests assignment to the conodont A. triangularis or slightly younger Zone of mid Frasnian age. Conodonts indicate that the Long Rapids Formation in Moose River Basin ranges in age from mid Frasnian at the base to early Famennian at the top (Sanford and Norris, 1975). Lithologically, the Long Rapids Formation is closely comparable to the Kettle Point Formation of southwestern Ontario, but its age span is more restricted.

38 MESOZOIC STRATIGRAPHY The Paleozoic succession of the Hudson Platform is succeeded by rocks of Mesozoic age in the Moose River Basin (Fig. 2.5). The latter sequence includes continental beds of Middle Jurassic age referred to informally as the Mistuskwia Beds (Telford and Verma, 1982); continental beds o f Early Cretaceous age named the Mattagami Formation (Dyer, 1928); and ultramafic igneous dykes and sills of Late Jurassic-Early Cretaceous age that intruded part of the Devonian succession near the southern margin of the Moose River Basin (Sanford and Norris, 1975; Telford and Long, 1986). ECONOMIC GEOLOGY Paleozoic rocks of the Hudson Platform contain deposits of limestone, gypsum, salt, siderite and limonite, and oil shale; and the succession has been studied sporadically for hydrocarbon possibilities (Johnson et al., 1986). Large quantities of limestone of varying composition are readily accessible along the railway lines crossing the Hudson Bay Lowland in northern Ontario and northern Manitoba. The more promising and accessible high calcium limestone in Moose River Basin includes outcrops of the Devonian Kwataboahegan and Murray Island formations, and the upper member of the Williams Island Formation. The gypsum deposits in the Devonian Moose River Formation of Moose River Basin have attracted attention because of their high purity, conspicuous outcrops, and location near routes of travel. The main outcrops are on Cheepash and Moose rivers, a slightly elevated area known as Gypsum Mountain, and on Wakwayokastic River (Sanford and Norris, 1975, Fig. 4). Salt deposits are widely distributed in the Hudson Bay Basin where they form part of the Ordovician Red Head Rapids Formation, the SilurianDevonian Kenogami River Formation, and the Devonian Stooping River Formation. These occurrences are in the subsurface and located mainly offshore beneath Hudson Bay where they are not easily recoverable. Siderite and limonite occur as replacement deposits in the Devonian Stooping River and Kwataboahegan formations at three localities at Grand Rapids on Mattagami River (Sanford and Norris, 1975, p. 92, Fig. 4). The deposits are of good quality, but the tonnage is insufficient for commercial development at the present time. Shales classified as oil shales (Macauley, 1984, p. 4) occur within three stratigraphic units in the Hudson Platform as follows: the Upper Ordovician Boas River shale of Heywood and Sanford (1976) on Southampton Island; the uppermost Upper Ordovician "oil shale interval" of Nelson and

39 and Johnson (1966, 1976) on Southampton Island; and t h e Upper Devonian Long Rapids Formation i n Moose R i v e r Basin. Of these, o n l y t h e " o i l shale i n t e r v a l " o f Nelson and Johnson has been adequately t e s t e d w i t h analyses which i n d i c a t e an average y i e l d o f 13 g a l l o n s o f o i l per ton. The more r e c e n t assessments o f t h e o i l and gas p o s s i b i l i t i e s o f t h e Hudson P l a t f o r m are by Sanford and N o r r i s (1973) and Sanford (1980). No authenticated seepages have been found i n t h e land areas o f t h e Hudson Platform and o n l y minor shows o f o i l and gas have been r e p o r t e d from t h e subsurface. The Phanerozoic succession i n t h e Moose R i v e r Basin i s r e l a t i v e l y t h i n (up t o 760 metres), i s r e l a t i v e l y l a c k i n g i n mature source rocks w i t h t h e p o s s i b l e exception o f t h e Long Rapids Formation, has been subjected t o block f a u l t i n g , and p o t e n t i a l r e s e r v o i r rocks do n o t appear t o be adequately sealed. The Hudson Bay Basin has a much t h i c k e r Paleozoic succession, up t o 1575 o r more metres t h i c k , b u t d r i l l i n g i n both onshore and o f f s h o r e regions has n o t revealed good prospects.

Large post-Kenogarni

River b l o c k - f a u l t e d s t r u c t u r e s have been t e s t e d i n t h e c e n t r a l p a r t o f t h e bay w i t h no p o s i t i v e r e s u l t s . Source rock p o t e n t i a l i s l a c k i n g i n t h e area, and two s t r u c t u r e s tested, appear t o have been breached b e f o r e being sealed by younger rocks. Other promising s t r u c t u r e s are known from seismic work i n Hudson Bay and these remain t o be t e s t e d by f u t u r e d r i l l i n g . REFERENCES 1974. Ordovician conodont b i o s t r a t i g r a p h y o f t h e Canadian Barnes, C.R., A r c t i c . I n : J.O. A i t k e n and O.J. Glass ( E d i t o r s ) , Proceedings, Symposium on t h e Geology o f t h e Canadian A r c t i c . Geological Survey o f Canada and Canadian S o c i e t y o f Petroleum Geologists, pp. 221-240. Barnes, C.R., Jackson, D.E. and Norford, B.S., 1976. C o r r e l a t i o n between Canadian Ordovician zonations based on g r a p t o l i t e s , conodonts and b e n t h i c m a c r o f o s s i l s from key successions. In: M.G. Bassett ( E d i t o r ) , The Ordovician System; Proceedings o f a Palaeontological Association Symposium, Birmingham, September 1974, U n i v e r s i t y o f Wales Press and National Museum o f Wales, C a r d i f f , pp. 209-226. Barnes, C.R., Norford, B.S. and Skevington, D., 1981. The Ordovician System i n Canada, C o r r e l a t i o n c h a r t and explanatory notes. I n t e r n a t i o n a l Union o f Geological Sciences, P u b l i c a t i o n No. 8, 26 pp. Bassett, C.F., 1935. S t r a t i g r a p h y and paleontology o f t h e Dundee Limestone o f southeastern Michigan. Geological Society o f America, B u l l e t i n , 46: 425-462. Berry, W.B.N. and Boucot, A.J., 1970. C o r r e l a t i o n o f t h e North American S i l u r i a n rocks. Geological S o c i e t y o f America, Special Paper 102, 289 pp. Bird, J.B., 1953. Southampton Island. Department o f Mines and Technical Surveys, Canada, Geographical Branch, Memoir 1, 84 pp. 1979. S i l u r i a n . In: R.A. Robison and C. T e i c h e r t ( E d i t o r s ) , Boucot, A.J., T r e a t i s e on I n v e r t e b r a t e Paleontology, P a r t A, I n t r o d u c t i o n , F o s s i l i z a t i o n (Taphonomy), Biogeography and Biostratigraphy. The Geological S o c i e t y o f America, Inc., and t h e U n i v e r s i t y o f Kansas, Boulder, Colorado and Lawrence, Kansas, pp. A167-A182.

40 Coombs, D.B., 1954. The physiographic subdivisions of the Hudson Bay Lowlands south of 60 degrees North. Department of Mines and Technical Surveys, C anada, Geographical Bulletin 6, pp. 1-16. Cranswick, J.S. and Fritz, M.A., 1958. Coral fauna of the Upper Abitibi Limestone. Geological Association of Canada, 10: 31-81. Cum ming, L.M., 1971. Ordovician strata of the Hudson Bay Lowlands i n northern M antioba. In: A.C. Turnock (Editor), Geoscience Studies i n Manitoba. Geological Association o f Canada, Special Paper 9, pp. 189-197. Cum ming, L.M., 1975. Ordovician strata o f the Hudson Bay Lowlands. Geological Survey of C anada, Paper 74-28,93 pp. Dimian, M.V., Gray, R., Stout, J. and Wood, B., 1983. Hudson Bay Basin. In: Seismic expression of structural styles; a picture and work atlas. A. W. Bally (Editor), A m erican Association of Petroleu m Geologists, Studies i n Geology Series, N 0. 15, V. 2, pp. 2.2.4-1-2.2.4-4. Dutro, J.T., Jr., 1981. Devonian brachiopod biostratigraphy. In: Devonian biostratigraphy o f New York, P a r t l . W.A. Oliver, Jr. and 6. Klapper (Editors), International Union o f Geological Sciences, Subcom mission on Devonian Stratigraphy, pp. 67-82. Dyer, W.S., 1928. Geology and economic deposits of the Moose River Basin. Ontario Department of Mines, Annual Report, 37: 1-69. Dyer, WS. ,. 1930. Paleozoic geology of the Albany River and certain o f i t s tributaries. 0 ntario Department of Mines, 38: 47-60. Ethington, R.L. and Furnish, W. M., 1959. Ordovician conodonts from northern M anitoba. Journal o f Paleontology, 33: 540-546. Flower, R.H., 1968. Silurian cephalopodsfrom James Bay Lowland, with a revision o f the Family N arthecoceratidae. Geological Survey of Canada, Bulletin 164, 88 pp. Fritz, M.A. and Cranswick, J.S., 1953. Lower and Middle Devonian of the James Bay Lowland. Geological Association o f Canada, Proceedings, 6: 69-74. Fritz, M.A., Lemon, R.R.H. and Norris, A.W., 1957. Stratigraphy and palaeontology of the Williams Island Form ation. Geological Association o f Canada, Proceedings, 9: 21-40. G uillet, G.R., 1964. Gypsum i n 0 ntario. 0 ntario D epartm ent o f Mines. Industrial Mineral Report 18, 126 pp. Heywood, W.W. and Sanford, B.V., 1976. Geology of Southampton, Coats, and Manse1 Islands, District o f Keewatin, Northwest Territories. Geological Survey o f Canada, M em oir 382, 35 pp. Hobson, G.D., 1964a. Ontario-Hudson Bay Lowlands, thickness o f sedimentary section (Paleozoic t o Cretaceous) from reconnaissance seismic refraction survey, M arch and April, 1964. Ontario Department o f Mines. Hobson, G.D., 1964b. Nine reversed refraction seismic profiles, Hudson Bay Lowlands, M anitoba. Geological Survey o f C anada, Paper 64-2, pp. 33-40. Hobson, G.D., 1967. R econnihsance seismic refraction survey o f Hudson Bay, Canada. reprinted from Proceedings o f the 7th World Petroleum Congress, pp. 813-826. Hood, P.J., Hobson, G.D., Norris, A.W. and Pelletier, B.R. (Editors), 1969. Earth Science Symposium on Hudson Bay, Ottawa, February, 1968. Geological Survey o f Canada, Paper 68-53,386 pp. Hueber, F.M., 1983. A new species o f Baragwanathia from the Sextant Formation (E msian), northern Ontario, Canada. Botanical Journal o f the Linnean Society, 86: 57-79. Jaanusson, V., 1979. Ordovician. In: Treatise on Invertebrate Paleontology, P a r t A, Introduction, Fossilization (Taphonomy). R.A. R obison and C. Teichert (Editors), Biogeography and Biostratigraphy, The Geological Society of America, Inc., and the The University o f K ansas, Boulder, C olorado, and L awrence, K ansas, pp. A136-A166. Jackson, D.E., 1971. Development of Glyptograptus hudsoni sp. nov. from Southam pton Island, North west Territories, C anada. Palaeontology, 14: 478-486. Johnson, R.D., Joubin, F.R., Nelson, S.J. and Olsen, E., 1986. Mineral Resources. In: I.P. Martini (Editor), Canadian Inland Seas, Elsevier, Amsterdam.

41

.,

Kindle, E. M 1924. Geology o f a portion o f the northern part o f the Moose River Basin, 0 ntario. G eological Survey o f C anada, Sum m ary R eport, 1923, pt. CI, pp. 21-41. Kirchgasser, W.T. and House, M.R., 1981. Upper Devonian goniatite biostratigraphy. In: Devonian biostratigraphy of New York, PartI. W.A. Oliver, Jr. and G. Klapper (Editors), I U GS, Subcom mission on Devonian Stratigraphy, Washington, D.C., pp. 39-55. Klapper, G., 1981. Review o f New Y ork biostratigraphy. In: Devonian Biostratigraphy of New York, PartI. W.A. Oliver, Jr. and G. Klapper(Editors),IUGS, Subcom mission on Devonian Stratigraphy, Washington, D.C., pp. 57-66. L arsson, S. Y 1984. Silurian paleontology and stratigraphy o f the H udson Bay Lowlands i n western Quebec. M.Sc. thesis, McGill University, Montreal, 188 pp. Le Wvre, J., Barnes, C.R. and Tixier, M., 1976. Paleoecology o f Late Ordovician and Early Silurian conodontophorids, H udson Bay Basin. In: C onodont Paleoecology. C.R. Barnes (Editor). Geological Association o f Canada, Special Paper 15, pp. 69-89. 1953. The Sextant Formation and itsflora. M.A. thesis, University o f Lemon, R.R.H., Toronto. Macauley, G., 1984. Geology o f the o i l shale deposits of Canada. Geological Survey o f Canada, Paper 81-25, 65 pp. Martison, N.W., 1953. Petroleum possibilities o f the James Bay Lowland area. 0 ntario Department of Mines, 61: 1-58. McCracken, A.D. and Barnes, C.R., 1981. Conodont biostratigraphy and paleoecology of the Ellis Bay Form ation, Anticosti Island, Quebec, with special reference t o Late Ordovician-E arly Silurian chronostratigraphy and the systemic boundary. Geological Survey of C anada, Bulletin 329, pp. 51-134. McGregor, D.C. and Camfield, M., 1976. Upper Silurian? t o Middle Devonian spores of the Moose River Basin. Geological Survey of Canada, Bulletin 263, 63 pp. McGregor, D.C., Sanford, B.V. and Norris, A.W., 1970. Palynology and correlation of Devonian form ations i n the M oose River Basin, northern 0 ntario. Geological Association o f Canada, Proceedings, 22: 45-54. McL aren, D.J., 1962. Middle and early Upper Devonian rhynchonelloid brachiopods from western Canada. Geological Survey of Canada, Bulletin 86, 122 pp. Miller, A. K., 1938. Devonian am m onoids of A m erica. Geological Society o f A m erica, Special Paper 14, 262 pp. Nelson, S.J., 1963. Ordovician paleontology o f northern Hudson Bay Lowland. Geological Society o f A m erica, M em oir 90, 152 pp. Nelson, S.J., 1964. Ordovician stratigraphy of northern Hudson Bay Lowland. Geological Survey of Canada, Bulletin 108, 36 pp. Nelson, S.J. and Johnson, R.D., 1966. Geology o f Hudson Bay,Basin. Bulletin, Canadian Petroleum Geology, 14: 520-578. 1976. O i l shales on Southampton Island, northern Nelson, S.J. and Johnson, R.D., Hudson Bay. Bulletin, Canadian Petroleum Geology, 24: 70-91. Norford, B.S., 1970. Ordovician and Silurian biostratigraphy of the Sogepet-Aquitaine K askattam a Province N 0. 1 well, northern M anitoba. Geological Survey of C anada, Paper 69-8,36 pp. Norford, B.S., 1971. Silurian stratigraphy of northern Manitoba. In: Geoscience studies i n Mantioba. A.C. Turnock (Editor), Geological Association o f Canada, Special Paper 9: 199-207. Norford, B.S., 1981. The trilobite fauna o f the Silurian Attawapiskat Formation, northern 0 ntario and northern M anitoba. Geological Survey o f C anada, Bulletin 327, 37 pp. Norn's, A. W., i n press. Geology of the Hudson Platform. In: J.D. Aitken and D.F. Stott (Editors), Continental Interior Platforms o f Canada, Decade o f North A m erican Geology. Geological Survey of C anada. N d s , A. W. and Uyeno, T.T., 1983. Biostratigraphy and paleontology o f Middle-Upper Devonian boundary beds, Gypsum Cliffs area, northeastern Alberta. Geological Survey o f C anada, Bulletin 313, 65 pp.

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42 Oliver, W.A., Jr. and Klapper, G. (Editors), 1981. Devonian Biostratigraphy of New Y ork, Part 2. I U GS, Subcom mission on Devonian Stratigraphy, Washington, D.C., 69 PP* Pollock, C.A., Rexroad, C.B. and Nicoll, R.S., 1970. Lower Silurian conodontsfrom northern Michigan and 0 ntario. Journal o f Paleontology, 44: 743-764. Remick, J.H., Gillain, R.R. and Durden, C.J., 1963. Geology of Rupert Bay, Missisicabi River area. Quebec Department o f Natural Resources, Preliminary Report 498,20 pp. Sanford, B.V., 1980. Evaporite deposits o f the Hudson Bay region, P a r t IV. Geological Survey of Canada, unpublished internal report, 67 p. Sanford, B.V. and Grant, G.M., 1976. Physiography (of) eastern Canada and adjacent areas. Geological Survey of C anada, M ap 1399A (4 sheets), scale 1:2,00O,OOo. Sanford, B.V., Grant, A.C., Wade, J.A. and Barss, M.S., 1979. Geology of eastern C anada and adjacent areas. Geological Survey of C anada, M ap 1401 A, (4 sheets), scale 1:2,000,000. Sanford, B.V. and Norris, A.W., 1973. The Hudson Platform. In: R.G. McCrossan (Editor), The future petroleum provinces of Canada their geology and potential. C anadian Society of Petroleum Geologists, M em oir 1: 387-409. Sanford, B.V. and Norris, A. W., 1975. Devonian stratigraphy o f the Hudson Platform, P a r t I Stratigraphy and economic geology; P a r t I1 0 utcrop and subsurface sections. Geological Survey o f C anada, Memoir 379,372 pp. Sanford, B.V., Norris, A.W. and Bostock, H.H., 1968. Geologyof the Hudson Bay Lowlands (Operation Winisk). Geological Survey o f Canada, Paper 67-60: pp. 1-45. Savage T.E. and Van Tuyl, F.M., 1919. Geology and stratigraphy of the area of Paleozoic rocks i n the vicinity o f Hudson and James Bays. Geological Society o f America, Bulletin, 30: 339-378. Sweet, W.C., Ethington, R.L. and Barnes, C.R., 1971. North American Middle and Upper Ordovician conodont faunas. In: W.C. Sweet and S.M. Bergstrom (Editors), Symposium and conodont biostratigraphy. Geological Society of A merica, Memoir 127: 163-193. Telford, P.G. and Long, D.E.F., 1986. Mesozoic geology of the Hudson Platform. In: I.P. Martini (Editor), Canadian Inland Seas, Elsevier, A msterdam. Telford, P.G. and Verma, H.M. (Editors), 1982. Mesozoic geology and mineral potential of the Moose River Basin. Ontario Geological Survey Study 21, 193 pp. Tillement, B.A., Peniguel, G. and Fuillemin, J.P., 1976. Marine Pennsylvanian rocks i n Hudson Bay. Bulletin, C anadian Petroleum Geology, 24: 418-439. Uyeno, T.T., Telford, P.G. and Sanford, B.V., 1982. Devonian condonts and stratigraphy of southwestern 0 ntario. Geological Survey o f C anada, Bulletin 332, 55 PP.

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