LOW-T THERMOCHRONOLOGIC CONSTRAINTS FOR THE ONSET TIMING AND SLIP HISTORY OF THE SOUTHERNMOST PART OF THE TETON FAULT, WYOMING

The timing and rate of movement along the range-bounding Teton normal fault is critical to our understanding of all lower order geologic interpretations for the Teton-Yellowstone region. Most studies have attributed movement along this structure to either: (1) Basin and Range extension, (2) encroachment of the Yellowstone hotspot, or (3) a combination of both mechanisms. In addition to the influence these mechanisms have in understanding the tectonic evolution of this area, this region lies within the most seismically active zone along the Intermountain Seismic Belt (ISB). Despite this, there is a notable absence of seismicity along the trace of the Teton fault yet LiDAR imaging across the fault reveals offset across glacial moraine deposits, indicating that some degree of fault rupture has occurred since the last glacial period. The juxtaposition of these seemingly incompatible observations as well as the patterns of high seismicity surrounding the Teton fault creates an enigma about the present-day seismic hazard. In a previous study, inverse thermal history models yield fault motion ages of 13-8 Ma, 10 Ma-present, and 7 Ma-present from three subvertical transects in the immediate footwall of the northern, central, and southern parts of the range front, respectively. In the previous study, this apparent southward younging of Teton fault activity is limited to only a few samples per transect and thus there is a need for additional cooling data to be generated in the southern and central Teton regions. Moreover, the southern area of the Tetons is the most heavily populated area in close proximity to the fault (Jackson, Wilson, Moose, Teton Village). In an effort to address this, we present the results from a new subvertical transect collected in the vicinity of Static Peak, ~6 km north of the previous southernmost transect at Rendezvous Mountain and discuss the implications that this data may have for both present-day seismic hazard and growth models for large continental normal faults.