An Overview of Paleozoic-Mesozoic Structures Developed in the Central White-Inyo Range, Eastern California

The central White-Inyo Range of eastern California is composed of a 7.5 km thick succession of Neoproterozoic to Upper Cambrian sedimentary rocks that have been deformed into a series of NE and N to NW-trending folds. The map distribution of the sedimentary rocks is primarily controlled by the younger N to NW-trending folds that define the White Mountain-Inyo anticlinorium. Smaller-scale folds and associated cleavage, which strongly fans in a divergent pattern about the fold hinge surfaces, are associated with both periods of fold development. Older NE-trending folds and associated cleavage are developed in a NW-trending belt that crosses the range in a structural saddle between the White Mountain and Inyo anticlines. These NE-trending folds are of smaller wavelength than the older N to NW-trending regional-scale folds, although both fold generations are developed on the cm-km scale. The intensity of both fold and cleavage development generally increases toward the west. Interference between the NE and the N to NW-trending folds has led to the development of a series of structural basins. We correlate formation of the NE-trending structures to the Antler orogeny, and formation of the younger N-to NW-trending structures with translation on the Last Chance thrust, which is exposed in the Inyo Range and presumably underlies the entire central White-Inyo Range. In the eastern and central portions of the range, it is clear that both periods of folding pre-date the emplacement of Jurassic and Cretaceous plutons that are correlatives to the intrusive suites exposed in the Sierra Nevada batholith to the west. On the western margin of the range another set of N to NW-trending structures, which are coaxial with the earlier N to NW-trending set, is probably associated with the East Sierran thrust belt; this thrust belt is better recorded in the southern Inyo Mountains, and developed in the Jurassic period.