Evidence for right-lateral transfer faulting accommodating en echelon Miocene extension, Mojave Desert, California

Abstract

In the southwestern United States, two early Miocene extensional terranes, one along the Colorado River trough and the other in the central Mojave Desert, have been inferred to be part of an en echelon rift system linked by a ductile detachment at depth. Evidence from pre-Tertiary surface geology in the central and western Mojave Desert suggests that a zone of east- to northeast-trending right-lateral strike-slip faulting may have transferred extension between these two areas. These data include the apparent offsets of the Late Jurassic age Independence dike swarm, a Middle to Late Jurassic age deformation belt, Triassic(?)-Jurassic volcanic rocks, Lower Triassic sedimentary rocks, and late Paleozoic age stratigraphic and tectonic elements. This inferred fault zone probably served as the main shallow-crustal kinematic link between extension in the central Mojave Desert and in the Colorado River trough.