Structural provinces in the north-central Gulf of Mexico can be defined using different criteria. First, they can be delineated based on the Miocene gravitational failure of the passive margin in response to proximal clastic loading. Extension occurred near the advancing shelf-slope break, shortening was concentrated in the Atwater Foldbelt, and the area in between was dominated by translation with only minor extension or contraction. The eastern margin of this cell of basinward translation marks the lateral edge of the Miocene depositional system and occurs along several strike-slip structures in east-central Mississippi Canyon. The western margin, trending NNW in central Green Canyon, was controlled by the distribution of allochthonous salt, with gravitational failure to the west accommodated primarily above extensive canopies in more proximal positions.

Alternatively, structural provinces can be identified based on the styles of salt withdrawal, diapirism, and canopy formation. A distal domain is characterized by vertical feeders, broadly symmetrical evacuation structures, and salt that spread radially to form salt-stock canopies. In contrast, a much larger, more proximal domain is dominated by inclined, welded feeders, asymmetrical expulsion rollovers, and salt that extruded primarily basinward to form salt-tongue canopies. In some cases, salt tongues were emplaced above deeper, still inflated Louann Salt, so that subsequent evacuation of the underlying salt resulted in anomalously deep canopies. Secondary minibasins later formed, producing deep, young minibasins floored by allochthonous welds only slightly above the Louann weld. The boundary between the salt-stock and salt-tongue provinces is unlikely to be related to basement architecture or Louann Salt thickness. Instead, it is interpreted to represent a toe-of-slope that varies in age from west to east.