Tertiary extensional features, Death Valley region, eastern California

The southeastern part of the Death Valley region (Fig. 1) displays two remarkable structural features: turtlebacks (Curry, 1938) and the Amargosa chaos (Noble, 1941). The changing ideas during the past half-century about the origin of these features reflect the growth of understanding of the major aspects of Basin and Range tectonics. Although these features were initially believed to be related to thrust faulting, a consensus now exists that they are different aspects of widespread Tertiary extension associated with the development of the Basin and Range province. The evidence upon which this historical debate is based is discussed in the site descriptions presented herein.