Cordilleran Foreland Tectono-Sedimentary Element, Canadian Northern Interior Plains

Abstract

Abstract Upper Jurassic–Paleocene siliciclastic strata comprise the Cordilleran Foreland Tectono-Sedimentary Element of Canada's northern Interior Plains. These strata record four major packages deposited on top of Paleozoic shelf strata on the NW margin of the Canadian craton. These packages are a Jurassic interval interpreted to record deposition associated with extension at the Arctic Ocean margin, a Lower Cretaceous, dominantly marine, interval deposited on the flexural margin of the foreland basin, and two Upper Cretaceous intervals of west-to-east progradational marine and non-marine strata deposited on the orogenic margin. The full succession has been affected by Cordilleran deformation within the Mackenzie Plain, Franklin Mountains and Colville Hills. Organic-rich shale is documented from Lower and Upper Cretaceous successions but these strata only reach thermal maturity in deeper parts of the basin, close to the Canadian Cordillera. Potential reservoirs exist within sandstone-dominated intervals throughout the succession, although some locally lack a top seal. One natural gas discovery has been reported from Upper Cretaceous sandstone of the Little Bear Formation at the Stewart D-57 well in the southeastern Mackenzie Plain. Oil sourced from Upper Cretaceous shale is reported from the Mackenzie Plain East Mackay B-45 well.