Upper Cretaceous Colorado Group in the Pasquia Hills, Northeastern : A Multidisciplinary Study in Progress

1 1 4 Claudia J Schroder-Adams , Dale A. Leckie , Jim Craig J' and John Bloch

Schroder-Adams, C.J ., Leckie. D.A .. Craig, J. and Bloch, J. ( 1998): Upper Cretaceous Colorado Group in the l'asquia 11 ills. northeastern Sac;katchewan: A multidisciplinary study in progress; in Summary of Investigations 1999. Volumt.: I. Saskatchewan Geological Survey, Sask. Energy Mines, Misc. Rep. 99-4. 1.

I. Introduction this volume; Cumbaa et al., 1992). It contains late Cretaceous bird bones (Tokaryk et al. , 1997). This and The upper part of the Upper Cretaceous Colorado the authors' continuous work on the Colorado Group Group (Cenomanian to Campanian) represents the led to a week's fieldwork in the Pasquia Hills during Cenomanian/middle Turonian Greenhorn and late the summer of 1997. Turonian/Santonian Niobrara sea-level cycles (Kauffman, 1984) and is widely distributed in the Western Sedimentary Basin (WCSB). Both cycles reflect times of high sea level and inundation of 2. Stratigraphic Framework the western side of when the Boreal Stratigraphic nomenclature used in this study (Figure and Tethyan seas were connected. Resulting sequences 1) is based on the comprehensive lithological and are dominated by organic-rich shale and approximately forarniniferal study of Cretaceous outcrops in the contemporaneous episodes of global anoxia (Arthur et Escarpment including the Pasquia Hills by al., 1987). Tectonic events and relative sea-level McNeil and Caldwell ( 1981 ). The stratigraphic interval fluctuations resulted in coarser elastic units found of interest here includes the Cenomanian Belle Fourche particularly in the western part of this fore land basin. Member of the Ashville Formation which correlates In contrast, the eastern part of the basin remained with the Belle Fourche Formation described by Bloch relatively deep throughout the Upper Cretaceous with et al. ( 1993, 1999). The Favel Formation is subdivided minor introduction of coarse elastics; but, sea-level into the Keld and members, which are of fa lls are recognized by dramatic paleontological latest Cenomanian to middle Turonian age and changes, and in erosional surfaces and bioclastic compare to the west with the Second White Specks conglomeratic ho rizons within black shale intervals. Formation, which is not subdivided into members. The Favel Formation is overlain by the Morden Shale. Age The Cenomanianffuronian boundary, a time of determination of the Morden remains imprecise due to approaching sea-level highstand and a major fauna! lack of age-diagnostic species, but is presumed to be of change from a Boreal to a Tethyan fauna in the middle Turonian age or younger (McNeil and Canadian portion of the seaway, is of particular interest Caldwell, 198 1) . Its western counterpart is not formally as its geological characteristics differ from place to described and commonly is referred to as unnamed place. At some localities it is marked by a bed of Colorado Shale (North and Caldwell, 1975). The bioclastic conglomerate, possibly the result of Niobrara Formation is informally subdivided into the winnowing over topographic highs within the basin. lower calcareous shale and upper chalky member Here, foraminiferal subzones are absent indicating which both correlate to the west with the informal First periods of erosion. Where bioclastic horizons are White Speckled Shale. In th e Manitoba Escarpment, it missing, fauna! change is gradational indicating a ranges in age from early Coniacian to early continuous record of sedimentation (Schroder-Adams Campanian, based on macrofossils and foram ini tera. In et al. , 1996). the Sweetgrass Arch area in southern Alberta/ Saskatchewan, paleontological evidence places the The composit ion of the bioclastic conglomerate correlative First White Speckled Shale into the changes across the basin, largely due to sediment Santonian (Schroder-Adams et al., 1998). The supply differences. In the Rocky Mountain Foothills, Niobrara Fonnation is overlain by the Pierre Formation Upper Cretaceous conglomerates contain abundant which is subdivided into four members which are in siliciclastic components and bioclastic debris whereas ascending order the Pembina, Millwood, Odanah, and in the east, more distal from Cordilleran siliciclastic an upper unnamed member (McNeil and Caldwell , sediment input, conglomeratic layers are mainly 1981 ). The entire Pierre Formation spans the bioclastic. An interesting bioclastic conglomerate bed Campanian. The lower portion of the Pierre Formation ofCenomanian age is present in the Pasquia Hills, is correlative with the Lea Park Formation of the eastern Saskatchewan (Cumbaa and Tokaryk, 1993,

I Department uf Earth Sciences. Carleton University, Ottawa. . ON K IS 5U6. 2 Wascana Energy Inc .. 635-8th Avenue SW. Calgary, AB T2P 4114. l Box 668. Bragg Creek, AB TOI. OKO. 'Scealu Mudus, 2617 Cutler /\venue. Albuquerque. NM 87106.

52 Summary of Investigations /999. Volume I SOUTHERN shale, siltstone, and very fine FOOTHILLS MANITOBA sandstone. The boundary with the PLAINS after McNeil after Blochetal, 1993 afterBlochetal, 1993 and Caldwell 1981 overlying Keld Member of the unnamed Favel Formation is marked by a Q) Bearpaw Bearpaw ...... Odanah benton ite, lack of silt and sand in ...... the Keld Member, and a change -~E Campanian a.LL Millwood from slightly calcareous to highly Pembina calcareous. Oyster shells are Belly River Milk River present throughout the Belle (U ...... Fourche and Keld members. The (U chalky First While ...... Belle Fourche Member is barren Soeckled Shale .0 Santoni an .QE calcareous of nannofoss ils which become Wapiabi Medicine Hat zu.. shale ·1bundant throughout the Favel Cf) unnamed Formation and indicate a Coniacian a. shale Morden ::, ...... :::J Turonian age. This age Q) 0 Shale 0 0. ,._ Cardi um Cardi um determination is confinned by the 0. c (0 (9 a. unnamed appearance of planktic w :) ·c Opabin ::::J shale E Assiniboine (_) e cu E 0,._ LL foram inifera with in the Favel ::, t LL Haven Second iii Fonnation which are of the latest t- Q) (9 White > ~ .0 Q) co Keld Cenomanian to middle Turonian w c Vimy 0 Specks u.. Hedbergella loetter/ei Zone. a: c <( ...... 0 -0 (_) rtl (/) cu,._ Belle ·c .::t:. Sunkay Fourche In man y outcrops along the (0 0 E Belle E (.) - u.. Man itoba Escarpment, the 0 0 Barons c () l Fourche Laurier Limestone Beds form the (I) ~ ~Baron~ ~ u t1·,,"'- Fish Scales ·s; uppermost unit of the Keld ...... ~~f:}5'~'~ Crowsnest ..c Member (McNeil and Caldwell, Q) c: Westgate U) Westgate (0 :,;· Volcanics 1981 ). These beds, however, ~ 15 <( 0 VikinQ Newcastle were not disti nctly recogn ized in ...J <{ Mill Creek Joli Fou Skull Creek the Bainbridge River section. Oyster shells are found within the Figure I - S tratigraphic nomenclature of Upper Cret11ceous strata in the We1·1ern lower part of the Favel Canada Se,limentary Basin. Fonnation. The upper part contains multiple bentonites Saskatchewan western plains region (North and (figure 3). Caldwell, 1975). The uppermost shale un it is the Morden Shale. The highly calcareous Assiniboinc Member shows a gradual transition to the slightly calcareous lower 3. Preli minary Results Morden Shale which grades upwards into non­ Fieldwork concentrated on three sections alono the calcar~o.us black shale (Figure 4). Rich planktic Bain bridge River, Carrot River, and Etomami R iver foramm ifera l assemblages of the Favel Formation (Figure 2). Sections were sampled for ~bruptly_disappear a~the boundary and change to an micropaleontolog_y (foraminifera and nannofossils) and 1mpovenshed agglutmated assemblage. Nann ofossils, ?rganic geochemistry (Rock-Eva!). Measured sections howeve_r, continue \n low numbers and are represented include the Cenomanian to Lower Campanian interval by species of the Niobrara Cycle; they indicate a encompassing in ascending order the Belle Fourch e Coniacian to Santonian age. Member of the Ashvi lle Formation Keld and Assiniboine members of the Favel Formation, Morden b) Carrot River Shale, Niobrara Formation and Pierre Formation (Figure I). This interval is represented by five A long the bank of the Carrot River, a 90 cm th ick shale foraminifcral zones and fou r su bzones (Caldwe ll et al. section features the Belle Fourche Member of the 1978). , Ashville Fonnation (Figure 5) (S. Cumbaa, pers. comm., 1997). The boundary is marked by a bioclastic cong(omerate layer including abundant vertebrate a) Bainbridge River remams (Cu~baa and Tokaryk, this volume) overlain The Bainbridge River section includes the Belle by a 5 cm thick bentonite. The shale is non-calcareous Fourche Member of the Ashville Formation Keld and above and be low the bioclast ic horizon. Assin iboinc members of the Favel Formatio'n. and Morden Shale (rigurc 3 ). c) Etomami River The Belle Fourche Member is a non-calcareous shale The section at the F.tomami Rive r includes the with a b_ioclastic horizon at 50 cm foll owed by a ~iobrara Forr:nation and the overl ying Pierre coarsen mg-upwards cycle of bioturbated interbedded Formation (Figures 6 and 7). The Niobrara Formation was informally subdivided by McNei l and Caldwell

Saskatchewan Geological S urvey 53 Bainbridge River i (/) i 20 non-calcareous ~ SASKATCHEWAN lish debtls ,g-:/iiii:/i:. shght1y calcareous Bf:J:B umxum highly calcareous A M UU:X KXJXXJX L A 15 . ~~:~:~:~:~:~ XJlJ:X X JlJC XlJlX ... B N I:Ii :::::...... • •••• biodastic. E I ~ I '"""'""'"''" l ·c: :_t~~t!:.: X XXXXXXXltXJl XXXX Bontonlilo R T ; :"' '-""" 0,1ter sno11S t 1 1 .·.·_·_·_·_·_·_·_·_·_·_·_· T 0 ... I. Biol...... "' 10 A B ? 9 } ;,,"''.1::::::::::::- A ~ 8 :;:;:5::~, ::::- Carrot River i ::, l1nely laminated ·.-tt~~f-. XXXJO(X XXXX JI lnocef'amus 3:1 ., fish debns 6 ::s ;"'\::::::::: "' l'Nghty cabreous 5 tttt1 nmuuu ~htty cakar~ Hudson Bay• @ 11111: '; bt0tvrt>a6on in sandstones ~ starved npples 0 ....·--· · ···-····-·-····-·-· non -calcareous

~ / v f f m c ~ ~..,!Ji- :$'~ san dstone 8 O Regina " Figure 3 - Measured section at the Bainbridge River.

4. Work in Progress Future integration of foraminiferal and nannofossil data will provide further stratigraphic constraint for the entire interval. Faunal and floral analysis in combination with Rock-Eva! data will aid in 500 km paleoenvironmental interpretations connected to Figure 2 - Location map ofoutcrops in the Pasquia Hills, Cretaceous sea-level history. Sections in the Pasquia Saskatchewan (after Cumbaa and Tokaryk, this volume). Hills refl ect an eastern facies where pelagic biogenic sedimentation was dominant within the northern ( 198 I) into the lower calcareous shale member and the portion of the Western Interior Seaway, and was distal upper chalky member. The boundary in this outcrop from sources of high elastic input. Species diversities has yet to be determined using foraminifera evidence. and abundances of calcareous plankton were higher to According to McNeil and Caldwell ( 1981 ), both the east than to the west (McNeil and Caldwell, 1981; members bear distinctive assemblages. The Niobrara Caldwell et al., 1993; Schroder-Adams et al., 1996; Fonnation comprises a black shale interbedded with Bloch et al. , 1999). Correlations of these sections to multiple oyster beds in a fine sandstone matrix. The subsurface core and Rocky Mountain Foothills sections formation is calcareous throughout and shows a will further shed light on the diachroneity of both speckled appearance indicating the presence of transgressive cycles, paleoceanographic circulation nannofossils. Three bentonites occur at the top of the pattern, lateral basin changes, and _ba~in . formation. The boundary to the Pierre Formation is paleotopography in regard to continuity of eros~onal marked by a 5 cm thick transition to non-calcareous surfaces. This project will provide fo r the first time shale. The interval between 5 and 6 m is marked by a nannofossil biostratigraphy for the eastern facies of the swarm of seven bentonites (Figure 6). Canadian Western Interior Basin.

Along the Bainbridge River two bioclastic conglomerates were observed. One was found in situ within the Ashville Formation whereas the second one was found as fl oat in the river (Figure 7). Both

54 Summary of Investigations 1999. Volume I Etomami River 1.x.xxx BentoMe

cz=, Oysler bed with l ine sandston,e matrix Stratigraphic Unit

multiple oyster beds fish scales A m c sandstone

Figure 6 - Measured section at the Etomami River.

B

Figure 4 - A) Outcrop photograph of the Bainbridge River section showing the Favel Formation and overlying Morden Shale. B) Calcareous shales ofth e Favel Formation (people as scales). A

Carrot River xxxxx Bentonite ,..... bioclastic conglomerate

c: _2i 1 m o E ~ Q) non-calcareous E ~ O a, · U MM1J1fA~~L...... u.. "fl .$ ~ 0 5 ] if . non-calcareous

B 0 Figure 7- A) Outcrop photograph ofth e Etomami River section .fhowing the upper Niobrara Formation and lower Pierre Formation. Some distinct white layers are bentonites (penwn for scale). B) Bioclastic conglomerate containing Figure 5 - Measured section at the Carrot River. large vertebrate debris/011nd as float in the Bainbridge River.

Saskatchewan Geological Survey 55 predominantly contain bioclastic material, but differ in Cumbaa, S.L., Tokaryk, T.T., and Jarzen, D.M. (1992): the size and composition of their components (Cumbaa Paleoecology of a Late Cretaceous near shore and Tokaryk, this volu me). Paleontological analysis marine environment; Canadian Paleontology will aid in the correlation and stratigraphic placement Conference, September 25-27, Ottawa, Prog. of these two conglomerates and will then allow Abstr. v2, p 11. regional correlations with other bioclastic horizons observed in Cenomanian sequences in the basin. Kauffman, E.G. ( 1984): Paleogeography and evolutionary response dynamic in the Cretaceous Western Interior Seaway of North America; in 5. Acknowledgments Westerm an, G.E.G. (ed.), Jurassic-Cretaceous Biochronology and Paleogeography of North We like to thank Steve Cumbaa and Rick Day for America, Geo!. Assoc. Can., Spec. Pap. 27, p273- inviting us to visit the Pasquia Hills field localities, for 306. sharing many stimulating scientific discussions and for their assistance in the field. M icropaleontological McNeil, D.H. and Caldwell, W.G.E. (1981): samples were processed by Patricia Brennan. Rick Day Cretaceous rocks and their Foraminifera in the is thanked for providing the location map. Financial Manitoba Escarpment; Geo!. Assoc. Can., Spec. assistance was provided by a NSERC Strategic Grant Pap. 21, 439p. to Schroder-Adams. North, B.R. and Caldwell, W.G.E., ( 1975): Foraminiferal faunas in the Cretaceous system of 6. References Saskatchewan; in Caldwell, W.G.E. (ed.), The Cretaceous System in the Western Interior of Arthur, M.A., Schlanger, S.O., and Jenkyns, H.C. North America, Geol. Assoc. Can., Spec. Pap. 13, ( 1987): The Cenomanian-Turonian Oceanic Event, p303-33 I. JI. Paleoceanographic controls on organic-matter production and preservation; in Brooks, J. and Schroder-Adams, C.J., Adams, P.J., Haggert, J. , Fleet, A.J. (eds.), Marine Petroleum Source Rocks, Leckie, D.A., Bloch, J., Craig, J. , and Mcintyre, D. Geol. Soc. Spec. Publ., v26, p401-420. ( 1998): An integrated paleontological approach to reservoir problems: Upper Cretaceous Medicine Bloch, J., SchrOder-Adams, Leckie, D.A., Craig, J., and Hat Formation and First White Speckled Shale in Mcintyre, D.J. ( 1999): Sedimentology, Southern Alberta, Canada; Palaios, vl3, p361-375. micropaleontology, geochemistry and hydrocarbon potential of shale from the Schroder-Adams, C.J., Leckie, D.A., Bloch, J., Craig, Cretaceous Lower Colorado Group in Western 1., Mcintyre, D.J., and Adams, P.J. (1996): Canada; Geo!. Surv. Can., Bull. 531, 186p. Paleoenvironmental changes in the Cretaceous (Albian to Turonian) Colorado Group of western Bloch, J., SchrOder-Adams, C.J., Leckie, D.A., Canada: Microfossil , sedirnentological, and Mcintyre, D.J., Craig, J., and Staniland, M. geochemical evidence, Cretaceous Resear., v 17, ( 1993 ): Revised stratigraphy of the lower pJ 11-365. Colorado Group (Albian to Turonian), ; Bull. Can. Petrol. Geo!., v41 , p325-348. Tokaryk, T.T .. Cumbaa, S.L.. and Storer, J.E. ( 1997): Early Late Cretaceous birds from Saskatchewan. Caldwell, W.G.E., Diner, R., Eicher, D.L., Fowler, Canada: The oldest diverse avifa una known from S.P., North, B.R., Stelck, C.R., and von Holdt North America, J. Vert. Paleont., vi?, p172-176. Wilhelm, L. ( 1993): Foraminiferal biostratigraphy of Cretaceous marine cyclothems; in Caldwell, W.G.E. and Kauffman, E.G. (eds.), Evolution of the Western Interior Basin, Geo!. Assoc. Can., Spec. Pap. 39, p477-520.

Caldwell, W.G.E., North, B.R., Stelck, C.R., and Wall, J.H. (1978): A foraminiferal zonal scheme for the Cretaceous System in the Interior Plains of Canada; in Stelck, C.R. and Chatterton, B.D.E. (eds.), Western and Arctic Canadian Biostratigraphy, Geo!. Assoc. Can., Spec. Pap. 18, p495-575.

Cumbaa, S.L. and Tokaryk, T.T. ( 1993): Early birds, crocodile tears, and fish tales: Cenomanian and Turonian marine vertebrates from Saskatchewan, Canada; Society of Vertebrate Paleontology Conference (Abstract), Albuquerque, Prog. Abstr., v1 3, p3 la-32a.

56 Summary of Investigations /999. I 'o/11me I