Variations in Bottom Processes Along the U.S. Atlantic Continental Margin: Rifted Margins

Seismic reflection data on strike lines along the slope and rise of the U.S. East Coast continental margin show variations in morphology and sedimentation pattern parallel to the margin. From these data, the regional versus localized extent of erosional or depositional features and events within each physiographic province of the margin can be determined. Two localized areas of extensive slope deposition were identified, one seaward of Albemarle Sound and the other seaward of the Delmarva Peninsula. A regional unconformity on the rise extends from Georges Bank to Wilmington Canyon and is believed to be Pliocene in age. The upper slope between Cape Hatteras and Hudson Canyon is dissected by many small valleys cut during the late Pleistocene, whereas northeast of Hudson Can on the upper slope is only cut by major submarine canyons. The Florida-Hatteras slope and Blake Plateau have many unconformities with one in late Tertiary truncating an extensive sequence of foreset beds on the north end of the Blake Plateau.