New Mexico Geological Society Annual Spring Meeting — Abstracts

Understanding how deformation is distributed within crustal rocks is central to studies of earthquake hazards and deformation processes. To address this question, we investigate how deformation is distributed in carbonate bedrock adjacent to the Alamogordo fault in south-central New Mexico. Our study area is Mule Canyon in the foothills of the Sacramento Mountains near Alamogordo, New Mexico.

To quantify fault activity, we produced a 1:5,000 neotectonic map documenting the offset of Quaternary geomorphic surfaces. To assess bedrock fracture densities, we analyzed the number of fractures, their orientations, and the types of veining we observed at 14 points within the canyon. All bedrock measurements were made within the Montoya Formation, a crystalline dolomite with lenses of massive quartz. At each point, a 1.4-meter circle was drawn on the bedrock surface, and the number of fractures was recorded. We also measured the orientation (strike and dip) of bedding and fractures, bedding thicknesses, and any development of secondary mineral precipitation. The data from the neotectonic mapping and bedrock fracture analysis correlates the number of fractures with the distance from the Alamogordo fault. We observed a decrease in the number of fractures and karst features in the bedrock with increasing distance from the fault zone.