Thrust faults in east-central New Mexico

A belt of southeast-vergent thrust faults, at least 60 km long and 15 km wide, was recognized on seismic sections from central and northeastern Guadalupe County, New Mexico. These results are basement cored, and typically extend upward to approximately 500 m below the surface. Locally, the fault systems offset the Triassic uppermost sedimentary cover. Individual thrust slices generally average 7 km in width and commonly are bounded on the northwest by high-angle normal faults. Other manifestations of these features that affect the surface along strike include broad arching, low-amplitude folds and localized dissolution. The thrust belt is situated on the southeastern margin of the ancestral Sierra Grande arch, and is inferred to have resulted from reactivated structures. Because of their northeast-southwest orientation, the thrusts are also interpreted as products of early Laramide compression directed from the west. If so, the thrust are the most distant known to have been operating in the foreland region southeast of the Colorado Plateau microplate during this phase of deformation.