Stratigraphic and Structural Variation along the Upper Continental Slope, Northwest Gulf of Mexico

Abstract

Detailed structural mapping and seismic sequence analysis along the upper continental slope in the Garden Banks and East Breaks Areas reveal notable variations in the area underlain by salt, the degree of salt formation, and the area and thickness of associated intraslope basins. East of 94.5{degree}W, salt occupies nearly 40% of the area and appears to be highly deformed. Here salt has moved both vertically and laterally to form a complex arrangement of salt diapirs, ridges, and sheets. The transition between areas is marked by a zone of large north-south trending faults. East of these faults most intraslope basins are well defined by surrounding salt bodies and by thick expanded sedimentary sections. To the west of 94.5{degree}W, salt occupies about 11% of the area and there are only a few isolated diapirs, a few dissected salt sheet remnants, and a single allochthonous salt tongue. Here the sedimentary section thins rapidly and individual intraslope basins are shallower and less well defined. From these observations the authors conclude that the eastern area is underlain by a greater amount of original salt, both vertical and horizontal salt movement were important in creating the salt configuration in both areas, salt in the eastern areamore » is more highly deformed, and the possibility exists of a basement high in the west that controlled the original distribution of salt deposited during the Jurassic and later sediment thickness deposited during the Pleistocene.« less