Geophysical Studies of Basin Geometries in West Texas, Southern New Mexico, and Northern Mexico

G. Randy Keller, J. H. Hinojosa, M. V. Deangelo

The west Texas, southern New Mexico, and northern Mexico area contains numerous, some overlapping, basins. These basins reflect the complex tectonic history of the region. The Paleozoic, Mesozoic, and early Cenozoic basins are potential exploration targets, but many of the younger Cenozoic basins are deep, posing a problem for interpreting geophysical data. Our ongoing gravity studies in the area have been successful in terms of delineating the late Cenozoic basins. The deepest of these basins are associated with the Rio Grande rift, and their geometry indicates a major shift in the direction of this structure at the latitude of El Paso. Laramide basins are also difficult to separate from the younger basins, on the basis of gravity data alone. However, limited amounts of eismic reflection data indicate the Laramide basins reach significant thickness. The Paleozoic basins (Delaware, Marfa, Orogrande, and Pedregosa) present distinct geophysical signatures. However, gravity and magnetic data indicate the basement is very complex. Most of this complexity seems to be due to late Precambrian-early Paleozoic rifting, which established the structural framework of the area.

AAPG Search and Discovery Article #91034©1988 AAPG Southwest Section, El Paso, Texas, 21-23 February 1988.