Recent surveys and investigations in the Gulf of Mexico have provided sufficient new data to warrant an updated regional geomorphic classification. The Gulf region is divided, according to the methods used by geomorphologists for continental areas, into three major geomorphic divisions and sixteen provinces. Some of the provinces are further subdivided into sections and subsections.
Most sections of the continental shelf contain Pleistocene wave-cut terraces. The lowest terraces generally lie near a depth of 65 fm.
The continental slope is considered here to be a major geomorphic division, rather than a province, because of its variety of land-forms and areal differences in geomorphic history. The steepness of the continental slope ranges from 2° on the DeSoto Slope to greater than 45° over limited areas of the reef-formed West Florida and Campeche Escarpments. Diapirs underlie all non-carbonate slopes and have largely altered the pre-existing topography.
Great thicknesses of evenly bedded sediments underlie the Gulf floor. The deeper sediments were derived from the northwest and pre-date the salt tectonism that produced the Sigsbee Escarpment and the numerous diapirs.