Abstract

Landsat and NASA High Altitude Special Mission Aircraft imagery have made it possible to define at least six separate lineament trends between the Amarillo-Wichita Uplift (N 62° W) and the Texas Lineament (N 54° W) that are 200–330 miles long and oriented N 54° W to N 62° W. These long lineaments are thought to be P shears and are left-lateral wrench faults by definition. Wrench faults, transcurrent faults, and strike-slip faults are basically synonymous and all are shear faults. Wrench faults in the Earth’s crust are characterized by the following: 1) Very long, straight traces; 2) High angle of dip (faults with over seventy degrees dip should be examined closely); 3) En echelon nature of faulting; 4) Associated angles between faults that suggest shear patterns; 5) Earthquake history in the region; 6) Offsets.

This left-lateral wrench fault system has been demonstrated at the Carta Valley Fault Zone. The Permian surface between Brown-Bassett and JM Field of Terrell, Crockett, and Val Verde counties along the Pecos River has a fracture system that is compatable with wrench faulting. In Garza and Borden counties, the elements of left-lateral wrench faulting can be demonstrated from high altitude aircraft imagery and demonstrated on the surface and in the subsurface with seismic support.

Surface lineaments are observed on Landsat imagery throughout the Permian Basin and leads to the belief that the very long N 54° to 62° W lineaments are P shears. The set oriented N 86° ±E are the Riedel shears and the N 36° E are conjugate Riedel shears. These form high angle en echelon faults of a left-lateral wrench fault system that can be documented with faulting on the surface in Borden and Garza counties with the surface alignments being documented on CDP seismic lines in the subsurface.