--> Abstract: Lacandonian Fold and Salt Belt, Southern Mexico, by Aranda, Mario; Olvera-Barroso, Irasema S.; Gonzalez-Posada, Fernando; and Martinez-Medrano, Martin; #90166 (2013)

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Lacandonian Fold and Salt Belt, Southern Mexico

Aranda, Mario1; Olvera-Barroso, Irasema S.; Gonzalez-Posada, Fernando; and Martinez-Medrano, Martin
1[email protected]

Lacandonian fold and salt belt (LFSB) refers a group of folding and salt structures widely extended in southern Mexico, from Chiapas mountains to the subsurface of the southern portion of the Gulf of Mexico across the Tabasco and Veracruz states in the coastal plain.

LFSB boundaries are Yucatan block (YB) in southeast and Anegada-Los Tuxtlas block in the northwest. LFSB structures are buried beneath Trans-mexican volcanic belt in the north and segmented by Motagua-Polochic fault zone in the south. Definition and evolution of this belt and blocks related are showing here throughout regional maps and balance cross sections mainly in the contractional areas.

LFSB was built by Late Jurassic shales and carbonates, Cretaceous carbonates and Tertiary clastics, all of them developed above a Jurassic evaporite substratum, except toward the northern middle of Veracruz basin. The stratigraphic column was deformed during the Neogene by progressive contraction process. Structural complexes was formed by typical saline-contractional detachments and basement inversion with salt related. Saline-extensional detachments were developed in both, the autochthonous evaporite substratum and the allochthonous salt, similar to those contractional and salt-related structures formed in Zagros Mountains, North Sea and Gulf of Mexico.

Regional and local evidences demonstrate that the belt's backstop probably are basement rocks of the Chiapas, La Mixtequita and Cuicateco massifs, which were contracted dozens of kilometres, toward northeast, against craton blocks forming thick and thin contractional and reactive salt structures, with growth-strata that record structure development.

Where LFSB has a considerable salt substratum, contractional folding and faulting detach and extend largely to the foreland forming a regional structural arch, knows as Akal block (AB). The Salina (SB) and Comalcalco (CB) basins at the western edge of the AB, have thicker salt substratum than AB. Typical basinward salt structures like diapirs (passive, active or reactive), walls and canopies occur in SB and landward extensional counterregional system is bordering the contractional. The Macuspana basin (MB) between AB and YB presents oblique extension and inverted rollovers.

An assortment of diapirs, contractional and extensional structures occur in LFSB, they are typically hydrocarbon traps since the last middle century in Mexico. Even though there should be more traps without tested economic potential.

 

AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013