ABSTRACT: Structural and Stratigrapic Evolution of the East Georges Bank Basin, Offshore Nova Scotia, Canada

A. B. Carswell, T. Koning, D. C. Hibbs

The East Georges Bank Basin is located offshore Nova Scotia on the southeastern Canadian continental shelf. The basin covers 2.5 million ac and is one of the last undrilled basins in North America. The geological interpretation is almost entirely based on 16000 km of seismic data over the basin. Pertinent well control is limited to 10 wells on the United States portion of the Georges Bank (West Georges Bank Basin) and two wells on the Scotian shelf. Seismic-stratigraphic analysis of this data has led to a structural and stratigraphic model for the basin.

The basin formed during the Triassic when the landmass of Pange began separating along rift zones. A prominent Paleozoic basement high, the Yarmouth Arch, separated the East Georges Bank Basin from the West Georges Bank Basin and had a dominant influence on sedimentation until the Middle Jurassic. Early synrift sequences consist of lacustrine clastics and shales. Marine incursions began in the late Triassic resulting in massive salt deposits that reflect the restricted extent of the basin and the arid Triassic and Early Jurassic climate. Further continental separation during the Early Jurassic resulted in deposition of carbonates and evaporites followed by Middle Jurassic continental shelf carbonates and deltaic sands. During the Middle Jurassic, major growth faulting and halokinesis as initiated by progradation of the deltaic sands. Post-Middle Jurassic continental spreading in combination with changing climatic conditions resulted in a steady decline of carbonate sedimentation and dominance of clastic deposition throughout the remaining history of the basin.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990