Structural domains and their potential impact on recharge to intermontane-basin aquifers

Variations in the structures exposed in structural domains associated with faults can affect the amount of ground-water recharge to fractured rock aquifers supplying intermontane-basin aquifers. In the southwestern Franklin Mountains, El Paso, Texas, an outcrop of the Ordovician Scenic Drive Formation exposes a group of structures including faults, joints, and folds associated with a left-lateral fault striking N74°E and dipping 81°NW. Slip along this fault has produced a structural domain with extensional structures (normal faults and joints) and a domain with contractional structures (folds and joints). These extensional and contractional domains occur on opposite sides of the fault.