STRIKE-SLIP FAULTING ALONG THE WASSUK RANGE OF THE NORTHERN WALKER LANE, NEVADA

Walker Lake is a fault-controlled basin along the Wassuk Range front in the Walker Lane shear zone. Geologic observations suggest that motion along the range-bounding faults of Walker Lake is predominately dip-slip. Nevertheless, geodetic measurements indicate that the right-lateral strike-slip motion is equal to or greater than the extensional component of slip. New terrestrial and submarine observations adjacent to the Wassuk Range and within Walker Lake show the presence of a strike-slip fault zone outboard and subparallel to the Wassuk rangefront. The remnant shorelines of pluvial Lake Lahontan that reached its highstand about 15,475 ± 720 cal. yr B.P. are displaced between about 12 - 15 m and lead to a right-lateral slip rate estimate of the fault approaching 1 mm/yr or greater. A record of strike-slip displacement is also preserved in high quality CHIRP seismic profiles acquired in Walker Lake about 15 km south of the observed shoreline offsets. The data image intense folding consistent with strike-slip deformational patterns observed elsewhere. Based on sedimentation rates, the onset of the strike-slip deformation is ~15, 300 yrs BP with the cessation of deformation being ~10, 140 yrs BP. Sediment divergence along the western portion of the lake records tectonic deformation along the Wassuk rangefront; the most recent episode of deformation is dated as 3000 yrs BP. The analysis of conventional low-sun angle photography, LiDAR, and seismic CHIRP imagery provides another example of the partitioning of slip between primarily normal and strike-slip faults that occurs in regions of oblique extension. These observations begin to reconcile what has been a mismatch between geodetically predicted deformation rates and geological fault slip rate studies along the Wassuk rangefront.