LATE CENOZOIC HISTORY AND SLIP RATES OF THE FISH-LAKE-VALLEY, EMIGRANT-PEAK, AND DEEP-SPRINGS FAULT ZONES, NEVADA AND CALIFORNIA

Several well-dated stratigraphic markers permit detailed assessment of the temporal and spatial variation in slip rates along the interconne cted faults of the Fish Lake Valley, Emigrant Peak, and Deep Springs F ault zones in west-central Nevada and east-central California. Right-l ateral mol:ion on the Fish Lake Valley fault zone apparently began ca. 10 Ma (11.9-8.2 Ma). Associated extensional faulting probably began c a. 5 Ma (6.9-4 Ma) and resulted in the opening of Fish Lake Valley and Deep Springs Valley. The long-term lateral slip rate for the Fish Lak e Valley fault zone since about 10 Ma is 5 mm/yr (3-12 mm/yr). Our pre ferred lateral-slip rate for the central, most active part of the Fish Lake Valley fault zone decreased from about 6 to 3 mm/yr from the lat e Miocene to the early Pleistocene, increased to about 11 mm/yr during the middle Pleistocene, and decreased to about 3 mm/yr during the lat e Pleistocene. Extension may account for some of the change in lateral -slip rate during the Pliocene. The large increase in lateral-slip rat e during the middle Pleistocene is circumstantially linked to an incre ase in vertical-slip rates on the Fish Lake Valley and Deep Springs fa ult zones at about the time of the eruption of the Bishop ash (0.76 Ma ). Vertical-slip rates along the three fault zones are also related to fault strike; vertical rates are highest on north-striking faults and approach zero on northwest-striking Faults. The long-lived slip histo ry of the Fish Lake Valley fault zone fits a tectonic model in which t he Death Valley-Furnace Creek-Fish Lake Valley fault system is integra ted with right-lateral shear on faults of the central Walker Lane and the Eastern California shear zone to accommodate part of the Pacific-N orth American relative plate motion. Our research demonstrates that th e Fish Lake Valley fault zone accounts for about half the rate of 10-1 2 mm/yr of Pacific-North American plate-boundary shear accommodated wi thin the Basin and Range Province between about lat 37 degrees and 38 degrees N.