Abstract: Geologic Development of Cenozoic Continental Margin of Southeast Georgia Embayment

Douglas W. Edsall, William P. Dillon

Nine northwest-southeast traverses with a minisparker were made across the continental shelf, Florida-Hatteras Slope, and western part of the Blake Plateau between lat. 31°45^prime and 33°30^primeN. Two northeast-southwest traverses were run as tielines, one across the shelf just west of the shelf break, the other across the Blake Plateau near the southeastern end of each traverse. The acoustic-stratigraphic sequences on the minisparker records were dated by extrapolation of ages assigned to various vibracore and piston-core samples and to cores from two holes drilled by the Glomar Conception. The continental shelf and slope have formed by upbuilding and outbuilding on a sequence of Upper Cretaceous and Paleocene sediments. Sediments of Eocene and Oligocene age enerally are absent. Miocene, Pliocene, and Pleistocene sediments are restricted to the shelf and slope south of 32°30^primeN. On the north, they also are present on the Blake Plateau. The records clearly show the formation of the shelf and slope in a stable area, where dynamic equilibrium has been reached between sediment supply and the erosional activities of the Gulf Stream and its predecessors. North of 32°30^prime, depth decreases to the top of the Paleocene sequence. This decrease in depth coincides with an abrupt change in strike of erosional channels cut into the Paleocene sequence. These channels are filled with Miocene sediments overlain by Pliocene, Pleistocene, and Holocene sediments. The shallowness of the Upper Cretaceous-Paleocene sequences apparently deflected c rrents in the past and allowed Miocene, Pliocene, and Pleistocene sedimentation on the plateau north of 32°30^prime.

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