The Roles of Basement Architecture and Salt Distribution in the Sierra Madre Oriental Fold-and-Thrust Belt and its Foreland Basin, Northeastern Mexico

Rowan, Mark G.¹, Randall Marrett², Samuel Eguiluz de Antuñano³, Timothy F. Lawton⁴, Mario Aranda-Garcia⁵ (1) Rowan Consulting, Inc, Boulder, CO (2) The University of Texas at Austin, Austin, TX (3) Independent Consultant, Mexico (4) Institute of Tectonic Studies, New Mexico State University, Las Cruces, NM (5) Pemex Exploración y Producción, Poza Rica, Veracruz, Mexico

The Laramide orogeny in northeastern Mexico affected both the Sierra Madre Oriental fold-and-thrust belt (SMO) and its foreland, which includes the Parras, La Popa, and Sabinas basins and several basement highs. We synthesize existing studies with field observations and subsurface data to illustrate the complex three-dimensional geometry and highly variable structural styles, and ascribe the disparities to an originally complex rift-basin architecture, established during the opening of the Gulf of Mexico, and the consequent areal and thickness distribution of Jurassic salt.

Structural provinces include: (1) the Monterrey salient of the SMO, with elongate, isoclinal, salt-cored detachment folds formed in a trough of thicker salt between the Coahuila and Picacho basement highs; (2) adjacent areas of the SMO, where the salt and its cover onlapped the basement highs and were thrust toward the foreland; (3) the Potreros, where a narrowing of the salt-filled trough of the Monterrey salient resulted in periclinal folds because of the lateral constraints on salt budget; (4) the Parras basin, on the flank of the Coahuila basement high, with open folds detached on a higher, shale detachment due to the lack of salt; (5) the La Popa basin and parts of the Sabinas basin, where the thickest original salt led to the early establishment of diapirs that were subsequently squeezed during shortening; (6) the remainder of the Sabinas basin, with both basement inversion structures and thrusts detached at the salt and shallower levels; and (7) the inverted southwestern margin of the Burgos (Gulf of Mexico) salt basin.