LATE CENOZOIC EXTENSION AND SYN-TECTONIC SEDIMENTATION IN WEST-CENTRAL NEVADA: IMPLICATIONS FOR LINKAGE OF THE EASTERN CALIFORNIA SHEAR ZONE AND WALKER LANE

Pacific-North American plate boundary motion is partially accommodated by the Eastern California shear zone and Walker Lane. These NW-trending dextral shear zones are misaligned along strike and are linked in west-central Nevada in a region that is characterized by active ENE-striking sinistral faults and NW-SE extension. Within this region, a low-angle normal fault exposed in Tule Canyon, NV may form the central segment of a regionally-extensive detachment fault system with a strike length >50 km. The low-angle fault is cut by both strike-slip and high-angle normal faults. Tule Canyon also includes a previously undescribed stratigraphic section of silicic volcanic rocks and conglomerate that is hundreds of meters thick. Tilts of these strata decrease up-section, and a zircon (U-Th)/He age from one tuff bed intercalated with conglomerate is approximately 8.5 Ma. We interpret these strata as syn-extensional deposits that accumulated in half grabens formed during NW-SE extension following activity on the low-angle fault. Extension in westernmost central Nevada, including the Tule Canyon area, which occurred first along a low-angle detachment and subsequently by high-angle normal faulting, may play a key role in the transfer of plate boundary motion from the northern Furnace Creek fault, into the Silver Peak-Lone Mountain extensional system, and ultimately onto dextral faults of the Walker Lane.