2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM

Paper No. 10
Presentation Time: 11:20 AM

Tectonic Development of Northeastern Mexico from Late Middle Jurassic through Miocene Time

LAWTON, Timothy F., Geological Sciences/MSC 3AB, New Mexico State University, P.O. Box 30001, Las Cruces, NM 88003, tlawton@nmsu.edu

Post-Middle Jurassic structural evolution of NE Mexico, the region along the Gulf rim north of Ciudad Victoria and east of TorreĆ³n, was conditioned by basement structures formed during Jurassic extension. Extensional basins flanking the future Gulf of Mexico developed within already extensively uplifted and eroded basement in the Middle(?) Jurassic during continental breakup; in the Sierra Madre Oriental (SMO) the faults bounding these basins have dominant north trends, parallel to the transform margin of the western Gulf, but north of Monterrey, aeromagnetic anomalies indicate both north- and northwest-trending basement faults that broke pre-Jurassic basement into high-standing and subsided blocks. The northwest-trending faults have been interpreted as sinistral transcurrent structures that accommodated displacement of nuclear Mexico to the southeast, but sense and amount of Jurassic offset, as much as 800 km, remain debated. The Jurassic basins accumulated thick redbeds (Huizachal Group) in the SMO and evaporite (Minas Viejas Formation) in the Sabinas and La Popa salt basins, which later hosted extensive diapirism not observed in the Mexican salt basin of the SMO. These extensional basins were separated from the Gulf by an elongate, narrow basement platform, the Tamaulipas-Burro arch.

Crustal shortening in latest Cretaceous-Paleogene time reactivated the west-trending basement faults and inverted the Mexican salt basin and the Sabinas-La Popa salt basins as the Sierra Madre and Coahuila foldbelts, respectively, detached in Jurassic evaporite. The Tamaulipas-Burro arch system formed a backstop for major crustal shortening which did not appreciably affect the Gulf Coast to the east and northeast. Shortening of the foreland took place in the context of subsidence initiated by the SMO crustal load, but which continued beyond the end of shortening, into the Oligocene. Regional early Miocene uplift of approximately 5 km roughly equaled the earlier subsidence, suggesting a dynamic relationship to the subducted Farallon slab.