Abstract: Paleogeography and Paleoenvironments of Scotian Shelf, Offshore Eastern Canada

Clair Russell Ossian

The Scotian Shelf has been explored intensely for hydrocarbons with little success. Largely on the basis of seismic data and salt-diapir recognition, approximately 60 wells have been drilled. This study utilized all available well-log, lithologic, and paleontologic data to generate a paleogeographic and paleoenvironmental model that differs considerably from previous models.

Middle Jurassic to Upper Cretaceous strata demonstrate oceanographic changes associated with the opening of the North Atlantic (i.e., establishment of oceanic-current patterns, changes in shelf-sedimentation patterns), and detail development of a very large and stable delta-bar-lagoon complex. This delta was established during Late Jurassic time and grew quickly to the continental-shelf edge where it became associated with widespread littoral sand sheets, barrier-bar complexes, and lagoonal facies deposits. Because of the great areal stability of the delta complex, immense quantities of sand accumulated to make this delta and its associated barrier-bar complex one of the largest yet discovered.

The sedimentologic settings also appear to explain partly the lack of economically important hydrocarbon reservoirs (i.e., relation between depocenters and shelf edges, presence of high-energy littoral currents, and lack of appropriately located source-rock depocenters).

AAPG Search and Discovery Article #90968©1977 AAPG-SEPM Annual Convention and Exhibition, Washington, DC