Seismic Stratigraphy of Long Island Platform, United States Atlantic Continental Margin

Richard A. Jowett, D. R. Hutchinson

Approximately 2,000 km of single- and multichannel seismic reflection profiles collected over the Long Island platform on the United States Atlantic continental margin show that the basement beneath the platform was rifted prior to the separation of Africa from North America and that it subsided after the separation. Postrift sediment thicknesses range from less than 1 km in the northwest part of the platform to several kilometers in the southeast, near the Atlantis and Nantucket rift basins. Flanking the platform are the Georges Bank basin to the east and Baltimore Canyon Trough to the south, where sedimentary rocks are 10-15 km thick.

Nine major unconformities have been delineated in analysis of the seismic profiles. The most conspicuous unconformities are correlated with the end of rifting and the upper surfaces of the Bathonian, Tithonian, Albian, Turonian-Coniacian, Maestrichtian, upper Eocene, mid-Oligocene, and mid-Miocene sections. Ages are determined by tracing reflectors and unconformities to the COST (Continental Offshore Stratigraphic Test), AMCOR (Atlantic Margin Coring Project), and coastal wells. Several of these unconformities coincide with pronounced fluctuations in the Vail curve of relative sea level.

AAPG Search and Discovery Article #91041©1987 AAPG Eastern Section Meeting, Columbus, Ohio, October 7-10, 1987.