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Structural Profile of Pre-Mesozoic Rocks Along U.S. Atlantic Continental Margin

Robert C. Milici, Kenneth C. Bayer

The U.S. Geological Survey (USGS) seismic common-depth-point lines extending along the continental shelf from offshore New England to Florida transect several major geologic features, including the Cornwall-Kelvin fault near lat. 40°N and a possible continental suture on the Georgia shelf near lat. 32°N. Seismic reflectors in the Precambrian(?) to Paleozoic(?) terrane range from subhorizontal bands of significant contrast to disaggregated, greatly contorted reflectors. North of lat. 40°N, on the shelf east of Long Island, USGS line 12 trends eastward and contains numerous reflectors indicating thrust faults. Near the Cornwall-Kelvin fault, reflectors are disaggregated and contorted. To the south, along the coast from New Jersey to North Carolina, reflectors are subhorizontal to broadly folded and wavy bedded to disaggregated. Farther south, off the coast of South Carolina and Georgia, subhorizontal reflectors generally occupy the upper part of the sequence, overlying more disaggregated patterns down to the Moho discontinuity. In contrast, to the south of the proposed continental suture, subhorizontal seismic reflectors of high contrast extend downward from the base of the Mesozoic sequence to the Moho.

AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.