Margins of Gulf of Mexico

Abstract

Preliminary results of a long-term program to investigate the tectonic history of the Gulf of Mexico principally through the use of multichannel seismic reflection methods indicate that knowledge of the deep part of the Gulf contributes significantly to understanding of the evolution of its continental margins. Reasonable and usual stratigraphic principles, based on marine reflection data, can be used successfully to interpret the geologic history of such regions. The stratigraphic unit which contains the Upper Jurassic salt responsible for the diapirs of the deep Gulf of Mexico now can be recognized throughout this region, and diapirs have been located as far east as the base of the West Florida Scarp. Basement structural arches which seem responsible for the reef growth controlling the Florida and Campeche Scarps also are present in the Yucatan Straits. All of the post-Jurassic units of the deep Gulf of Mexico pinch out by depositional overlap against the Florida Scarp on the east, the Campeche Scarp on the south, and the newly discovered basement feature in the Florida Strait. There is no evidence of faulting associated with these scarps. The post-Jurassic through Miocene sedimentary rocks of the deep gulf originally continued north of the Sigsbee Scarp, and completely across the Mexican Ridges on the west. Deformation by detachment sliding and diapirism progressed southward on the United States margin throughout the Cenozoic and occurred suddenly in the folded Mexican Ridges in the late Pliocene or Pleistocene. There is no evidence in the deep Gulf of Mexico of pre-Pleistocene deep-sea cones. The large deep-sea cone of the present Mississippi River is a prominent and unique feature of the Gulf of Mexico.