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Active Tectonics of the Eastern California Shear Zone

Kurt L. Frankel, Allen F. Glazner, Eric Kirby, Francis C. Monastero, Michael D. Strane, Michael E. Oskin, Jeffrey Unruh, J. Douglas Walker, Sridhar Anandakrishnan, John M. Bartley, Drew S. Coleman, James F. Dolan, Robert Finkel, David Greene, Andrew Kylander-Clark, Shasta Marrero, Lewis A. Owen, & Fred Phillips

Published 2008, SCEC Contribution #1131

The eastern California shear zone (ECSZ) is an important component of the Pacific-North America plate boundary. This region of active, predominantly strike-slip, deformation east of the San Andreas fault extends from the southern Mojave Desert, along the east side of the Sierra Nevada, and into western Nevada. The ECSZ is thought to accommodate nearly a quarter of relative Pacific-North America plate boundary. Recent studies in the region, utilizing innovative methods ranging from cosmogenic nuclide geochronology, airborne laser swath mapping, and ground penetrating radar to geologic mapping, geochemistry and U-Pb geochronology, are helping elucidate slip rate and displacement histories for many of the major structures that comprise the ECSZ. This field trip includes twelve stops located along the Lenwood, Garlock, Owens Valley, and Fish Lake Valley faults, which are some of the primary focus areas for new research. Trip participants will explore a rich record of the spatial and temporal evolution of the ECSZ from 83 Ma to the late Holocene through observations of offset alluvial deposits, lava flows, key stratigraphic markers, and igneous intrusions, all of which are deformed as a result of recurring seismic activity. Discussion will focus on the constancy (or non-constancy) of strain accumulation and release, the function of the Garlock fault in accommodating deformation in the region, total cumulative displacement and timing of offset on faults, the various techniques used to determine fault displacements and slip rates, and the role of the eastern California shear zone as a nascent segment of the Pacific-North America plate boundary.

Key Words
United States, strain, Eastern California shear zone, guidebook, Owens Valley, slip rates, field trips, Clark County Nevada, Fish Lake valley, road log, California, Cenozoic, Lenwood Fault, Inyo County California, neotectonics, outcrops, tectonics, Pacific Plate, San Bernardino County California, faults, Nevada, shear zones, plate boundaries, North American Plate, Nye County Nevada, Garlock Fault, plate tectonics, San Andreas Fault, accommodation zones

Frankel, K. L., Glazner, A. F., Kirby, E., Monastero, F. C., Strane, M. D., Oskin, M. E., Unruh, J., Walker, J., Anandakrishnan, S., Bartley, J. M., Coleman, D. S., Dolan, J. F., Finkel, R., Greene, D., Kylander-Clark , A., Marrero, S., Owen, L. A., & Phillips, F. (2008). Active Tectonics of the Eastern California Shear Zone. In Frankel, K. L., & Glazner, A. F. (Eds.), GSA Field Guide 11: Field Guide to Plutons, Volcanoes, Faults, Reefs, Dinosaurs, and Possible Glaciation in Selected Areas of Arizona, California, and Nevada, (, pp. 43-81) Boulder, : Geological Society of America doi: 10.1130/2008.fld011(03).