Laramide Block Uplifts and Complementary Basins in Southern New Mexico

G. H. Mack, W. R. Seager

During the Laramide orogeny the foreland area of south-central and southwestern New Mexico was broken into several major, basement-cored, block uplifts and complementary basins. Geometry of the structures is similar in overall style to the Wind River and Owl Creek uplifts and Wind River basin of Wyoming. The southern New Mexico uplifts trend uniformly northwesterly and are asymmetric: they have narrow thrust- or reverse-faulted northeastern margins and much broader, gently dipping southwestern flanks. The sense of tectonic transport is toward the northeast with few exceptions. Complementary basins are filled with as much as 2,100 m (6,800 ft) of synorogenic and postorogenic clastic strata. The postorogenic strata, essentially of Eocene age, overlap and partly bury the upl fts, and the strata record erosional unroofing of the uplifts, locally down to the Precambrian.

In southwestern New Mexico, uplift-boundary thrust and reverse faults probably have an important component of right- and/or left-lateral slip. Complex structure along these faults, including low-angle thrust faulting, may be a product of convergent wrench faulting.

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