Limitations on Right-Lateral, Strike-Slip Displacement, Death Valley and Furnace Creek Fault Zones, California

Abstract

Sedimentary units of late Precambrian and Cambrian age in the southern Death Valley–Kingston Range region of eastern California contain several through going linear features with configurations that apparently place a several-mile limit on the total right-lateral displacement that may be assigned to the Death Valley–Furnace Creek fault system. Much greater magnitudes have been suggested previously. Precambrian paleogeologic contacts, recorded in the northeastward truncation of successively older units of the Pahrump Group by the unconformity at the base of the Noonday Dolomite, can be traced discontinuously as nearly straight features from the Kingston Range west-northwestward to the Panamint Range, about 75 miles. A belt of talc mineralization, which also trends west-northwestward, is marked by a crudely linear arrangement of deposits reflecting the distribution of a dolomitic facies of a carbonate unit in the lower part of the Pahrump Group. An “algal” dolomite unit, which forms the lower part of the Noonday Dolomite, thins to the southwest and terminates along a line that can be traced northwestward for about 25 miles along the east margin of Death Valley to Virgin Spring Wash and probably thence westward to the southern part of the Panamint Range. The plots of these linear features, all of which apparently cross either the Death Valley fault zone or Furnace Creek fault zone, or both, indicate that no more than 5 and 2 miles, respectively, of right-lateral, strike-slip movement has occurred on these zones. Indeed, the position and orientation of the lines require no lateral displacement at all for their explanation. Similar limitations on movement along Death Valley fault zone seem to be imposed by the presence, on the east side of Death Valley, of a wedge of shale and graywacke within the Noonday Dolomite. The wedge thins and becomes progressively finer-grained northeastward. It also contains a basal conglomerate with clasts of the “algal” dolomite and the Kingston Peak Formation. These features suggest a source area west of southern Death Valley. Right-lateral, strike-slip movement of 10 miles or more on the Death Valley fault zone, if restored, would anomalously juxtapose the clastic wedge with a terrane in the Panamint Range where the “algal” dolomite is preserved. The possibility that large-scale, right-lateral displacement in the region of central and southern Death Valley has been accomplished by crustal flexing, as advocated by some geologists, remains unsupported by the available structural data and is difficult to reconcile with the configurations of the geologic lines.