Tectonic Inversion Structures as a Geologic Guide to Map Early Mesozoic Basement Horsts and Grabens in the Western Gulf of Mexico

Ricardo Padilla y Sánchez
[email protected]

Several plate tectonics models have been proposed to explain the opening of the Gulf of Mexico (GOM), through the use of regional shear zones, strike-slip faults or even lineaments, as crustal discontinuities along which the basement blocks move to develop rifted basins and emerged horst blocks. However, the evidence that supports the location of such regional structures is scarce and difficult to interpret, thus leading to important misconceptions that complicate the proposed models. This problem is important in order to know how far into Mexico continues the Basin & Range Province? The precise location of the boundaries of rifts formed during the breaking-up and drifting apart of Western Pangea in the Late Triassic is an important guide to define the directions of displacement of the pre-Jurassic basement blocks linked to the opening of the Gulf of Mexico. Inversion structures are a useful evidence to locate these structures in the subsurface. In northern Mexico there are several well known horsts and rifts in Chihuahua, Coahuila, Nuevo León and Tamaulipas, but farther southward, in the hinterland of the Sierra Madre Oriental is more difficult to identify them. In this project some inversion structures cropping out in the hinterland have been mapped and interpreted as evidence of limits of ancient rifts.

AAPG Search and Discovery Article #90167©2013 GCAGS and GCSSEPM 63^rd Annual Convention, New Orleans, Louisiana, October 6-8, 2013