An integrated geological and geophysical study of the Salt Basin Graben, west Texas
— J. H. Veldhuis and G. R. Keller

The Salt Basin graben of Trans-Pecos Texas (fig. 1) is a 200 km (130 mi) long and 8 to 32 km (5 to 20 mi) wide topographic depression that trends approximately N10°W along the Culberson-Hudspeth County line into southern New Mexico. This basin separates the Diablo Plateau, Sierra Diablo, Carrizo and Van Horn Mountains (to the west) from the Guadalupe, Delaware, Apache and Davis Mountains (to the east). To the south the basin bifurcates around the Wylie Mountains forming Lobo Flat to the southwest and Michigan Draw to the southeast (fig. 1). The Salt Basin receives its name from the alkali lakes and dry alkali flats present mainly along the western edge of the basin from about 31°20'N latitude towards its northern end in Otero County, New Mexico. The basin fill is composed of a variable thickness of unconsolidated Cenozoic alluvial and lacustrine gravels, sands, silts and clays. According to King (1948), the Salt Basin graben represents a down-dropped portion of the earth's crust with rocks of the immediately adjacent mountains having been either warped or faulted down into their present positions. (See also Goetz, this guidebook.)

 

Previous studies of the regional tectonic and geologic setting of Trans-Pecos Texas have included the Salt Basin graben only as a side light. In this study, geological and geophysical data have been integrated in an attempt to further elucidate the subsurface geometry and tectonic setting of the basin. In addition to surficial geologic data, geophysical and geologic information was compiled in the form of gravity, magnetic and subsurface well data. The gravity and magnetic data were used to produce a regional Bouguer gravity map and regional total field magnetic intensity map. The subsurface well information (fig. 2; Table 1) was utilized along with geophysical constraints in producing computer-modeled cross sections across the Salt Basin graben and adjacent areas. These two-dimensional computer models were calculated using the technique of Talwani and others (1959).