Distribution of shallow salt structures, lower slope of the northern Gulf of Mexico, USA

• Published in: Marine and petroleum geology 1992-08, Vol.9 (4), p.433,IN1,449-448,IN12,451
• Main Author: Liro, Louis M.
• Format: Article
• Language: English
• Subjects: Earth sciences; Earth, ocean, space; Exact sciences and technology; Gulf of Mexico; Marine; salt tectonics; shallow salt structures; Tectonics. Structural geology. Plate tectonics
• ISSN: 0264-8172; 1873-4073
• DOI: 10.1016/0264-8172(92)90053-H

Shallow salt structures on the lower slope of the northern Gulf of Mexico are interpreted to be the manifestation of a unique geological situation: an unusually thick original salt layer mobilized and deformed by episodic Cenozoic sedimentary loading into a variety of shallow subsurface forms. Salt deformation, observed on seismic data, increases in intensity and complexity from the relatively simple shallow salt canopies of the Florida Escarpment area to partitioned and deformed shallow salt masses of the offshore Texas area. Salt ‘tongues’ (extensive lateral salt bodies in the shallow subsurface, with demonstrable sources) are observed from the Mississippi Fan area to the western edge of the lower slope. Salt tongues vary in style from subhorizontal, very shallow, laterally persistent tongues that comprise the frontal lobe of the Sigsbee Escarpment to adjacent undulatory, landward dipping tongues which rise obliquely through the sedimentary section. The salt tongues form a trend which defines the southern limit of shallow salt in the northern Gulf of Mexico. Shallow salt features landward of this trend are interpreted as earlier formed salt dome and tongue systems, the original shape and distribution of which were modified by partitioning of a precursor shallow salt feature by sedimentary loading. The morphology of the prominent Sigsbee Escarpment is due entirely to lateral and basinward movement of asymmetric salt masses. Lateral displacement of salt in these salt tongues is of the order of only tens of kilometres. The occurrence of dome-like features and withdrawal basins landward of the salt tongues suggests that the tongues originate from or in association with these domes.