Based on available nonexclusive seismic data, a preliminary model has been developed for salt deformation on the deep margin of the central Gulf of Mexico basin. In this model, the Tertiary clastic wedge prograded to the basinward limit of original Jurassic salt by the middle Miocene. As the salt and overburden thinned basinward, lateral flow, combined with a strong component of downward force exerted by subsiding voluminous middle Miocene loading, caused the basinward limit of the Louann Salt to effectively shear off. Deposition of the upper Miocene and Pliocene sediments was confined primarily shoreward of an incipient salt swell, but Pleistocene sediments were eventually able to breach the barrier.

Deformation of the detached salt produced the features present on the slope today. Preliminary work indicates that most of the detached salt was propelled basinward and upsection toward the present Sigsbee Escarpment, leaving pinch-and-swell salt structures behind. The various types of residual salt structures have been formed as a result of differences in the history of sedimentary loading. Different stages of development of pinch-and-swell structures, shown on seismic sections, illustrate this model.