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.