EFFECTS OF RIO GRANDE RIFT RELATED FAULTS ON DOMINANT FRACTURE TRENDS OF EL PASO’S THREE SISTERS INTRUSIVE FORMATION

Three Sisters is a shallow depth andesitic intrusion dated at 47-48 ma located in western El Paso, Texas. After exposure through potential rift-related processes, the area has undergone extensive faulting. Such faults have shaped the peaks and in turn have affected the dominant fracture directions of each peak. In saying that, the fracture directions measure at approximately the same angles, the only difference being the directions in which they trend. Fault processes forming the various fracture directions correlate with soon to be obtained apatite dates for uplift of Three Sisters intrusive body. What becomes of the apatite dating will give way to a possible driving force of the faults and fractures found at Three Sisters (i.e. rift-related processes or Laramide Orogeny mountain building processes). Utilizing Google Earth and a Brunton compass, presumed fractures and faults were measured for orientation analysis. The results are then plotted in a stereonet software to determine similarities and/or anomalies in the measurements recorded. Charts such as contour diagrams and rose diagrams are used to find dominant trend directions. In completing this project I hope to encourage future UTEP-ROCCS students to continue similar research at Three Sisters and/or other geologic locations in El Paso.