ABSTRACT

Geophysical and drilling operations within the area of the Grand Banks have established the existence of a thick sedimentary section that includes Tertiary, Mesozoic and Paleozoic strata. An angular unconformity that developed in Early Cretaceous time divides the section into two distinct geological units. The "upper wedge" is comprised of Tertiary and Cretaceous strata, while the "subunconformity basins" contain Jurassic and older rocks. The "upper wedge" is relatively simple, with regionally gentle dip, disturbed locally by salt-dome structures. The "subunconformity basins" contain a great variety of structural types, including salt domes, salt ridges, faults, drape folds over basement blocks, and major sedimentary truncations at the unconformity.

Principal contributors are W. G. Ayrton, D. E. Birnie, J. H. Swift and H. R. Wellman (Amoco), and J. F. Stevulak, D. C. Waylett, R. A. F. Wilkinson, J. D. Hamilton and D. B. Harrison (Imperial Oil).