Salt Movement on Continental Slope, Northern Gulf of Mexico

Abstract

Regional sparker lines across the continental slope of the northern Gulf of Mexico demonstrate the close relation between salt movement and sediment deposition. Salt features on the outer slope are not as well developed as those near the shelf because sedimentation has been much less on the slope. Salt-generated structures in the eastern part of the gulf are more mature than those in the western gulf because of higher rates of sedimentation. The youngest salt features on the outer slope are much larger than domes on the shelf. Seismic data from the outer slope suggest that salt dome growth in this area was initiated by southward salt flowage caused by sediment loading updip. The Sigsbee Escarpment appears to be a salt scarp (formed by this gulfward salt flowage) that has extruded over younger sediments for a considerable distance. Areas of salt diapirs in the Gulf of Mexico, with the exception of diapirs on much of the lower continental slope, are considered to be areas of original thick salt deposition. It is suggested that these areas of thick salt were deposited in one central rift in Jurassic time, and have moved to their present position by seafloor spreading. The present Red Sea is a model for the Gulf of Mexico at the time of Mesozoic breakup.