The Georges Bank basin is a basement structural depression beneath the continental shelf southeast of New England. The deepest part of the basin is an arcuate trough approximately 120 mi long, containing 26,000 ft or more of Mesozoic and Cenozoic sedimentary rock. This estimate is based on interpretation of geophysical data utilizing new velocity information from wells drilled on the western Scotian shelf.

Overall stratigraphic similarity to rocks in the western Scotian shelf is likely. Sedimentary rocks form a southward-thickening wedge beneath the continental shelf. Geophysical data indicate the existence of more than 14,000 ft of Lower Cretaceous and Jurassic carbonate rock, marine shale, evaporite, and consolidated sandstone, and as much as 12,000 ft of Upper Cretaceous and Tertiary sandstone and shale in the Georges Bank basin. Jurassic units in the basin are probably thicker than their western Scotian shelf equivalents. Salt diapirs similar to those in the Scotian shelf have not been detected. Structural deformation consists of high angle normal faulting in basement rocks.

Estimates of recoverable oil and gas from sedimentary rocks beneath the continental shelf and continental slope have been made by petroleum-industry groups and federal agencies. The 30,000 cu mi of Lower Cretaceous and Jurassic sedimentary rocks in the Georges Bank basin may contain a significant share of these hydrocarbon reserves, thus assuring the basin a favorable place among eastern North America's frontier exploration areas.