Cardium Formation 4. Review of Facies and Depositional Processes in the Southern Foothills and Plains, Alberta, Canada

Abstract The Upper Cretaceous (Turonian) Cardium Formation (Figs. 1, 2) is a dominantly sandstone unit surrounded by marine shales of the Alberta (= Colorado) Group. It was deposited in the Western Interior Seaway in Alberta. In the subsurface, the Cardium is a major oil and gas reservoir (Table 1, on next page). It crops out abundantly in several thrust slices of the Rocky Mountain Foothills, between the U.S. Border in southern Alberta and Dawson Creek, B.C., a distance of about 800 km. The Alberta Group spans the Cenomanian to early Campanian, a period of about 15 million years (Fig. 2), and the Cardium belongs to the upper part of the Turonian, implying that deposition of the Cardium may have occurred in as little as one million years (Palmer, 1983). In the Canadian Cordillera, there are two main clastic wedges, the late Jurassic-early Cretaceous Kootenay - Blairmore Assemblage, and the late Cretaceous - Paleocene Belly River - Paskapoo Assemblage. The Alberta Group presumably represents a period of relative tectonic quiescence between these two assemblages, with dominantly mudstones accumulating in the Alberta Basin.