Allochthonous salt, structure and stratigraphy of the north-eastern Gulf of Mexico. Part II: Structure

Abstract

The kinematic evolution of allochthonous salt in the north-eastern Gulf of Mexico proceeds in three stages. (1) Since its middle Jurassic deposition, the Louann Salt was loaded by sediments causing episodic basinward movement of salt, ultimately leading to large concentrations of salt masses in a slope environment by the end of the Lower Cretaceous. (2) A regime of starved sedimentation during Late Cretaceous and Early Oligocene is responsible for the stabilization of these early salt accumulations. (3) With renewed rapid accumulation of sediments, during the Neogene and Pliocene, extensive allochthonous salt tongues and sheets formed by gravity spreading within the younger sediments of the slope. Autochthonous salt, allochthonous salt and detached allochthonous salt are typical stages of evolution. Major down to the basin growth faults separate allochthonous salt sheets from their original feeder stocks. Extension along down to the basin master growth faults is compensated mainly by salt withdrawal and partly by basinward shortening.