QUATERNARY SURFICIAL GEOLOGIC MAP OF THE DRY MOUNTAIN NORMAL FAULT, DEATH VALLEY NATIONAL PARK, EASTERN CALIFORNIA

We present a detailed surficial geologic map of a regionally-prominent, ~25-km-long normal fault located within northwestern Death Valley National Park, eastern California, between Steel Pass to the north and Saline Valley to the south (herein named the “Dry Mountain fault”). The Dry Mountain fault dips to the west and forms a half-graben separating Dry Mountain in its footwall to the east from an elongated north-trending basin in its hanging-wall to the west. The Dry Mountain fault consists of ~1–3, closely-spaced, subparallel faults that are expressed as: (1) west-facing scarps with heights and continuous lengths up to ~10 m and ~3 km, respectively, within late Pleistocene(?) and older alluvial fan deposits, and (2) <1–10-m-wide, brittle fault zones along contacts between footwall Paleozoic bedrock strata and hanging-wall alluvial fan deposits. Fault zones along bedrock-alluvium contacts contain discrete, varnished fault surfaces that have an average dip of ~56°W. Striations on west-dipping fault surfaces are oriented down dip. Triangular facets and wineglass canyons are common along the length of the Dry Mountain fault. Faults are buried under Holocene(?) and active alluvial fan deposits. The Dry Mountain fault is likely kinematically linked with the Eureka Valley normal fault to the northwest via en echelon right-slip transfer faults at Steel Pass. At the southern termination of the Dry Mountain fault, fault scarps are significantly more distributed across southeastern Saline Valley. Evidence of dip-slip kinematics along the Dry Mountain fault and a lack of prominent strike-slip faults, which has also been observed along the Eureka Valley, Deep Springs, and Tin Mountain faults in the region, suggests that extension has been the dominant form of crustal deformation within the Eastern California Shear Zone between the right-slip Owens Valley and Fish Lake Valley-northern Death Valley-Furnace Creek faults.