Documenting Collapse of the Northern Paleo-Teton Range and Northern Extension of the Modern Teton Fault between Grand Teton and Yellowstone National Parks, WY

Funds are requested to support a student mapping project and associated analyses that examines a potential northern extension of the Teton fault in Grand Teton (GTNP) and Yellowstone National Parks (YNP), John D. Rockefeller Jr. Memorial Parkway, and the Bridger- Teton National Forest. In the northern Basin and Range, multiple mountain ranges abruptly terminate at the boundary with the Snake River Plain/supercaldera track, and this has been hypothesized to indicate that these ranges have been partially removed by multiple catastrophic caldera-forming eruptions. The proposed mapping area lies at the northern extension of the Teton Range, the range that most recently intersects the Yellowstone caldera, where N-S striking normal fault scarps variably offset rhyolites (<2.1 Ma) of the Yellowstone system. This is a critical area where the faults are exposed south of the ~70 ka Pitchstone Plateau rhyolite flow. The project aims to test the hypothesis that normal faulting associated with the actively extending Teton fault continues north into YNP. Existing mapping in the area was completed at a 1:62,500 scale and was less focused on the orientation of rhyolites and the magnitude of fault slip experienced by those units following their emplacement. This work, which will be completed by a Ph.D. student at the University of Kentucky under the close supervision of PI Thigpen, will produce a 1:24,000 scale geologic map of parts of the Grassy Lake, Cave Falls, Survey Peak, and Hominy Peak 7.5 minute quadrangles, with a total area of approximately one 7.5 minute quadrangle. Field mapping will be complemented by petrologic and structural analyses and potential new LiDAR acquisition in the Bridger-Teton National Forest using UAV equipment from the Kentucky Geologic Survey, the latter of which may aid in identification of previously unrecognized active fault scarps.