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Known collectively as "salt domes," slender diapiric stocks, broad massifs, anticlinal masses, low-relief swells, and pillowy lobes of Middle to Upper Jurassic salt dominate the structural fabric of large parts of the continental margins and deep basin of the Gulf of Mexico.
In the northern Gulf of Mexico, large salt structures are concentrated on the Texas-Louisiana slope west of the Mississippi fan and on the Rio Grande slope east of Brownsville, Texas. Salt stocks dot the continental shelf off Louisiana, around the DeSoto Canyon off the Florida Panhandle, and across the upper Mississippi fan between the Sigsbee and Florida Escarpments. At the foot of the continental slope, an almost continuous wall of coalesced salt structures abuts relatively undeformed strata of the continental rise along the Perdido and Sigsbee Escarpments marking the seaward boundary of the northern gulf salt-dome province.
In the central gulf, the almost featureless Sigsbee Plain is interrupted by the surface expressions of but a few of the more than 50 large salt diapirs that pierce thousands of meters of abyssal strata along a narrow belt parallel with the northwestern face of the Campeche Escarpment. Seismic reflection data between the Sigsbee Knolls and the Campeche Escarpment record the undulating surface and undeformed base of the mother-salt layer and indicate updip pinchout at the base of the Campeche platform.
In the southwestern gulf, knolls and open basins on the slope are underlain by masses of diapiric and non-diapiric material thought to be salt. Though similar to the northern gulf slope in topographic character and to some extent in internal structure, the Golfo de Campeche slope includes a considerable number of broad, linear hillocks composed of thick sections of slope and abyssal strata that were uplifted, folded, and faulted by tectonic events apparently unrelated to salt mobility.
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