Slender diapiric stocks, broad massifs, anticlinal masses, low-relief swells, and pillowy lobes of Middle to Upper Jurassic salt (Viniegra, 1971; Kirkland and Gerhard, 1971; Imlay, 1980) dominate the structural fabric of large parts of the continental margins and deep basin of the Gulf of Mexico (sht. 1, A). These structures, known collectively as "salt domes," are almost exclusively features of the terrigenous elastic margins of the northern and southwestern Gulf and the central Sigsbee Plain (sht. 2, A). Some salt structures may be present in the East Mexico Slope province of the western gulf, but they are difficult to distinguish from diapiric and nondiapiric shale anticlines, which are the dominant structures on this margin. Except for some piercement domes and nonpiercement uplifts in the northern Florida shelf region and in the eastern Golfo de Campeche, salt structures are not known in the extensive carbonate platform provinces off western Florida and the Yucatan Peninsula. The accompanying compilation from seismic-reflection data documents the distribution of Gulf of Mexico salt features and helps to define boundaries of structural provinces formed mainly, or in part, by tectonic movement of salt.
