Gravitational Analysis and Fault Identification Within an Active Rift Basin: The Mesilla Valley Bolson in Western Texas - Southern New Mexico
The metropolitan region of El Paso Texas and Ciudad Juárez, Chihuahua, located within the northern Chihuahua Desert, contains approximately two million inhabitants. The two main aquifers that supply groundwater to this region are the Mesilla and Hueco Bolsons. Both bolsons have been tapped for decades without sustainable recharge. This study’s purpose is to use geophysical methods coupled with published geochemical analyses to determine the structural and stratigraphic controls on the quality and quantity of groundwater in the southern Mesilla Bolson. The Mesilla Bolson is one of many fault-controlled basins within the Rio Grande Rift – southern Basin and Range. Faults control major aspects of the bolson, serving as barriers or conduits to the movement of fluids within the bolson. The main focus of this study is the Mesilla Valley fault, which appears to be the major fault controlling the geometry of the eastern side of bolson. Although other geophysical research projects have been conducted in the region, none have focused on the structure of the Mesilla Valley fault and the western margin of the Mesilla Valley. Over 250 data points were collected in a region specifically designed to cross the inferred position of the Mesilla Valley fault in several places. The additional data have updated the UTEP database and have established more confidence in the location of various faults in the Mesilla Bolson. An updated location for the Mesilla Valley fault was established as well as recognizing that some gravity anomalies that were previously mapped faults may represent the edges of igneous intrusions. My updated residual Bouguer anomaly map correlates well with surface Quaternary faults previously mapped in other studies. The updated Horizontal Gradient Magnitude map (HGM) confirmed the structural complexity of the basin due to various extensional and compressional tectonism.
Cervantes, Jose Pablo, "Gravitational Analysis and Fault Identification Within an Active Rift Basin: The Mesilla Valley Bolson in Western Texas - Southern New Mexico" (2018). ETD Collection for University of Texas, El Paso. AAI10931756.