Plio-Pleistocene strata of offshore Texas having hydrocarbon exploration potential are restricted to the southeastern continental shelf and upper continental slope. This thick wedge of nearshore and deep-marine sediments firms the west margin of a late Neogene and Quaternary depocenter. The wedge is divided into eight genetic sequences on the basis of well logs, paleontological reports, and seismic profiles.

The Hueco Basin of Trans-Pecos Texas, which formed in response to Cenozoic extensional tectonism, lies within the southern Rio Grande rift near the poorly defined boundary between the rift and the southern Basin and Range province. Subsurface data, including proprietary seismic lines, were studied in conjunction with aerial-photo and surface geologic mapping to determine the basin's structure and fault history. These data were also studied to evaluate the seismic risk of the basin and to consider it as a possible repository of low-level radioactive waste.