• Geology

• Geological Timescale
• Western Interior Seaway
• Plate Tectonics
• Rock Cycle
• Geological Formation

• Quick Links

• About Us
• Blog
• Media
• Hours & Admission
• Programs & Tours
• Vacation Packages
• Fossil Collection
• All About Bruce
• Contact Us
• FAQs

Museum Hours
10:00 am - 5:00 pm
year round

Geology

CRETACEOUS GEOLOGY OF MANITOBA

The Canadian Fossil Discovery Centre (CFDC) located in Morden, Manitoba houses the largest collection of marine reptile fossils in Canada (Janzic and Hatcher 2008; Nicholls 1988). Fossil excavation occurs annually along the Manitoba Escarpment within marine shale members the Pierre Shale Formation (Cretaceous: Campanian). The CFDC is unique in that the entire fossil collection is sampled from the Pembina Mountain region of the Manitoba Escarpment. There is a strong bias of the collection coming specifically from the Pembina Member of the Pierre Shale Formation, as that member was heavily excavated by Pembina Mountain Clays Inc. during the bentonite mining activities of the 1970’s and 1980’s. Today, field work encompasses all members of the Pierre Shale Formation, although fossil distribution remains most productive in the Pembina and Millwood Members due to exposures of these lithofacies.

Geological Setting

The Manitoba Escarpment is a physiographic feature that rises above the Red River Valley, extending north-westerly across the south-western portion of Manitoba. Cenozoic glacial activity is responsible for the current topography of Manitoba, especially the escarpment. This escarpment represents the easternmost edge of Cretaceous rocks within Manitoba. Recent revisions to the Cretaceous marine lithology in the United States elevated the Pierre Shale to Group status, with all previous members being elevated to Formation status and new members were designated. (Martin et al., 2007) The terminology is currently under review by the Manitoba Geological Survey to determine if the Pierre Shale will also be elevated to Group status in Canada, but for the time being it remains at the rank of Formation. (J. Bamburak, personal communication, January 16, 2009)
All of the current excavation sites are located in or directly adjacent to previously mined bentonite quarries where layers of shale are exposed. Collection and excavation are typically specific to the Pembina and Millwood Members of the Pierre Shale Formation. The basic lithology of the Pembina Member consists of non-calcareous black shale with numerous bentonite stringers near the base. (Bamburak and Janzic, 2007) The Pembina Member has a thickness of 7 metres with a trend to thin out towards the north. (Bamburak and Janzic, 2007) See Figure A for more on the stratigraphy of southern Manitoba.

References

Bamburak, J.D. and A. Janzic. 2007. Manitoba Paleontology Seminar, Abstracts and Field Manual, Canadian Fossil Discovery Centre, 34p.

Janzic, A. and J. Hatcher. 2008. Late Cretaceous Marine Reptile Fossils of the Canadian Fossil Discovery Centre. Alberta Palaeontological Society, Twelfth Annual Symposium, Abstracts Volume, p.28. Mount Royal College, Calgary, Alberta.

Nicholls, E.L. 1988. Marine Vertebrates of the Pembina Member of the Pierre Shale (Campanian, Upper Cretaceous) of Manitoba and their Significance to the Biogeography of the Western Interior Seaway. Ph.D. Thesis, University of Calgary, 317 p.

Martin, J.E., J.L. Bertog, and D.C. Parris. 2007. Revised lithostratigraphy of the lower Pierre Shale Group (Campanian) of central South Dakota, including newly designated members. In The Geology and Paleontology of the Late Cretaceous Marine Deposits of the Dakotas. Edited by James E. Martin and David C. Parris. Geological Society of America Special Paper 427, pp. 9-21.