STRUCTURAL ANALYSES OF LINEAMENTS IN THE CHRISTMAS MOUNTAIN RANGE AND THE EXTENT OF THE TASCOTAL MESA FAULT, TEXAS

The Christmas Mountains laccocaldera developed steep elliptical domes more than 42 Ma. Recently, the area has been modified by the southern Tascotal Mesa transtensional fault system with horizontal and vertical synthetic shear present along the Texas Lineament Corridor and the Texas-Chihuahua intracontinental transform zone. Previous observations show a visible trend of N10-20°W in the pattern of lineaments in the northern corner of the study area within a series of weathered volcanic units that show significant differences in composition and eruptive style. Pre-field work focused in identification, classification of orientation of the lineaments such as dikes, fractures, and faults using Google Earth Pro and ArcGIS to infer the paleostress. This will be followed by structural analyses of field data, mapping relationships and slope analyses to relate fracture systems to the topographically and structurally highest areas near the southeast that gently slope toward the northwest. The trends of structural features collected will be analyzed with statistical software Stereonet 9. The lineament patterns will be compiled in a geodatabase to support field mapping of major structural features of the Trans-Pecos region. Results from this research will combine the local study areas and provide a model of regional strain to distinguish compressional versus extensional forces. This research aims to explore the possibility that the intrusion of the laccolith took place in a weak transfer zone that propagated to the south. The remnants of the laccolith are hypothesized to hinder the slip of the Tascotal-Mesa Fault resulting in a fault termination. Our results will expand knowledge of the tectonics of the Trans –Pecos area while providing students with field research experience.