Robert Pelkey


B.Sc. (Honours) Thesis


Depositional Environment and Provenance of the Late Aptian to Early Albian Cummings Formation, East Central Alberta, and a Discussion Concerning Secondary Source Rock

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Through the interpretation of one cored section located within the Provost Oil Field of east central Alberta, the late Aptian to early Albian Cummings Formation, found within the Lower Mannville Group, has been interpreted as a transgressive estuary deposit. Basal channel incision followed by valley-fill deposits exhibit progressive marine influence through the presence of characteristic tidal bundles and asymmetrical current ripples demonstrating subordinate current flow. A low diversity suite of biogenic sedimentary structures, mixed Skolithos and Cruziana ichnofacies, also adhere to a transgressive estuarine depositional model. Abundant detrital chert, volcanic and lithic fragments observed through mineralogical analyses indicate a Cordilleran provenance. Organic petrographic analyses of organic matter within the Cummings Formation suggest a terrestrial source of potential gas producing type III kerogen. Vitrinite reflectance and rock evaluation results suggest the Cummings Formation is thermally immature. Poor total organic carbon percentages designate the Cummings Formation as being inadequate as a secondary source rock for the Provost Oil Field. Further understanding of depositional environments and sequence stratigraphic relationships within the Western Canadian Sedimentary Basin (WCSB) provides insight into hydrocarbon emplacement. This study also provides further stratigraphic resolution of the complex interval between the Lower and Upper Mannville Groups.

Pages: 126
Supervisors: Grant Wach