New Mexico Geological Society Annual Spring Meeting — Abstracts

The region east of the Rio Grande rift at Socorro is characterized by high- and low-angle faults as well as complex folding. The primary emphas is of on-going research is to determine the origin of the low-angle faults.

Several models have been proposed bya number of investigators to account for these features in this region:

1) Thrust faulting resulting from regional compression bewteen late Permian and early Triassic time; 2) Thrust faulting associated with Laramide wrench faulting; 3) Decollement (or detachment faulting) associated with early rifting (27 to 32 Ma); 4) Gravity gliding or sliding associated with oversteepened Laramide uplifts; and 5) Gravity gliding or sliding associated with epeirogenic uplift and late rifting (7 Ma to present).

Limited reconnaissance of more than 800 square miles east of the rift in Socorro County together with a few square miles (less than one-tenth of the area) of detailed geologic mapping suggest that any of the hypotheses may be feasible. The purpose of this study is to gather data to address these hypotheses, eliminate or modify weak ones and assemble the final the model (s) into a picture of the structural development of central New Mexico. This study will improve our understanding of the tectonic development of the rift in adjacent areas where only seismic data is available and structural relationships are poorly understood, and contribute to our interpretation of rift history and development in the State of New Mexico.