Geologic Mapping of Submerged Continental Margins: ABSTRACT

Abstract

In the late nineteenth century it was discovered that rocks dredged by fishermen from the continental slope contained Cretaceous and Tertiary fossils. In the mid-1930s, Stetson systematically dredged such rocks from the Georges Banks' submarine canyons, concluding that the canyons had been cut deeply into a presumed sequence of foreset and topset beds. Subsequently ancient rocks have been discovered on linear segments of the continental slope not near submarine canyons and it now appears that the continental slope from Newfoundland to Puerto Rico forms a continuous outcrop of Tertiary and Cretaceous sediments. Echo-sounding profiles of the continental slope show a succession of topographic benches and gradient changes which have been correlated in a few areas with the outcrop pattern determined either by coring and dredging or by extrapolation from nearby drill holes. Scattered and less complete data from other parts of the world suggest that continental-slope outcrop benches are of common, if not of general occurrence. By correlating benches dated and verified by dredging, it is possible to construct geological maps of the continental slopes. In addition to greatly adding to the geological understanding of the continental shelves, extensive continental slope outcrops are of great significance in such major geological problems as the origin of the continental slopes and the origin of the co tinents and oceans. End_of_Article - Last_Page 1250------------