Members of the Oceanography Department at Texas A&M University have conducted extensive geologic and geophysical surveys across the shelf-edge banks off Texas and Louisiana in the northern Gulf of Mexico. These prominent topographic features are the surface expression of isolated salt diapiric structures, in places capped by carbonate sediments and reefal communities. There is great variability in the details of their physiography and structure. However, analysis of the geophysical data indicates that the banks may be classified into three main structural types: (1) rectangular, fault-controlled, uplifted blocks of sedimentary strata; (2) circular domes modified by faulting more or less parallel with the shelf edge; and (3) circular domes with radial and/or annular fa lt patterns. The majority of the banks, particularly types two and three, show some evidence of collapse, probably a result of dissolution of salt. Based on the variety and regional setting of the observed structures, evolutionary models have been developed. Ubiquitous local topographic trends associated with the banks occur along the shelf edge and upper slope. They strike roughly northwest-southeast and may reflect structures formed during the early tectonic history of the Gulf of Mexico.

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