Paper No. 9-9
Presentation Time: 8:30 AM-6:00 PM
QUATERNARY FAULT ANALYSIS IN THE STEWART VALLEY, NEVADA
We use surface analysis and thermochronology to assess approximate fault locations in comparison to historical geologic mapping in the Stewart & Soda Springs Valley, west central Nevada. The Stewart Valley is bound to the west by the Gabbs Valley Range and east by the Cedar mountains. This area marks the transition between the basin and Range province which experiences east-west extension and the Walker Lane province dominated by right-lateral shear, accommodating a quarter of the stress between the Pacific and North American plates. The Stewart Valley is filled with Tertiary fluvial and lacustrine deposits of the Esmerelda formation with many small faults scattered in the valley. Accurate categorization of faults in these areas helps represent the tectonic dissection of the Stewart Valley in relation to transitional regional stress of the late-Miocene walker lane NW-SE shear in comparison to the mid-Cenozoic Basin & Range E-W extension. LiDAR collected along the Petrified Springs Fault, the Benton Springs Fault, and Landsat satellite imagery from 1970 to present are being used to identify apparent deformation of quaternary features like triangular facets, offset streams, fault scarps and beheaded streams. Analyses are ongoing; modern stream offset and triangular facets will be the most useful indicators for accurate placement of faults. These surface analyses will be used to assess recent quaternary deformation allowing comparison to older extensional regimes. Furthermore, four samples were collected in a horizontal transect along the Benton Springs Fault and are being analyzed for low temperature thermochronology. This data, combined with our analysis of quaternary deformation will reveal information about the timing of fault initiation, exhumation rates, and the transition into the present-day fault motion of the Eastern Walker Lane boundary.