EVIDENCE FOR LATE QUATERNARY ACTIVITY ON THE SEMINOE MOUNTAINS SECTION OF THE SOUTH GRANITE MOUNTAINS FAULT, CARBON COUNTY, WYOMING

The Seminoe Mountains section of the South Granite Mountain fault (SGMF) is currently classified as a Class B (potential Quaternary) structure in the USGS Quaternary Fault and Fold database. In addition to uncertainties associated with the Seminoe Mountains section fault characteristics, the location of the surface trace of the fault was mapped at a scale of 1:250,000 and is poorly constrained. In an effort to better constrain the location of the Seminoe Mountains section, surface lineaments were mapped at a scale of 1:10,000 along, or near previously mapped fault traces using a publicly available Digital Elevation Model (DEM) and Google Earth imagery. Surface lineaments which exhibit clear vertical offsets across Quaternary deposits were identified along 10 km of the 36 km length of the Seminoe Mountains fault. Where Quaternary deposits are visibly displaced, 2D profiles were extracted across topographic scarps in ArcMAP to estimate vertical offsets. Vertical surface offsets across Quaternary deposits ranged from 0.2 – 3.0 meters. No field verification of this mapping has been completed to confirm these interpretations and determine if these locations will add information to improve our understanding of Quaternary faulting along this fault segment. Field reconnaissance and a decision to excavate trenches or other geologic studies to quantify the activity of the fault in this section of the SGMF is pending.