STRUCTURAL REINTERPRETATION OF FEATURES WITHIN THE NOPAH-RESTING SPRING RANGES, CA AND THE SPRING MOUNTAINS, NV: A KEY FOR RESOLVING EXTENSIONAL MODELS IN THE DEATH VALLEY REGION USING 3D IMAGING AND SOFTWARE

Mesozoic thrust systems within the Chicago Pass region of eastern CA often have been used as piercing-points in the reconstruction of extensional structure in the Death Valley region. This study presents a re-evaluation of correlations used in different reconstructions. Pavlis et. al (2014, Geosphere) presented analyses of these thrust systems and new reconstruction scenarios based on overprinted structures that could represent unique piercing points. This study is a continuation of that work using GIS, multi-spectral imaging, and 3D analysis of the structures. Field mapping, combined with virtual mapping using high-res orthophotos draped upon a DEM, was used to develop 3D models of the more problematic features in the Nopah-Resting Spring Range and the Spring Mtns, NV. These 3D models are augmented by the interpolation of multi-spectral ASTER data to aid in separating limestone from dolomite in regions where the lithology is too similar to easily map by ground or air. Further complicating interpretations in this area are numerous landslide deposits, of currently unknown age, that commonly have been misinterpreted as coherent lithographic units. Our initial work suggests that: 1) correlation of a key thrust system in the Chicago Pass region, the Shaw thrust, which we previously correlated with the Resting thrust in the Resting Spring Range, seems unlikely because where last seen the Shaw thrust is converging on the Chicago Pass thrust, implying it tips out to the west; 2) the correlation of the Shaw thrust with the Lee Canyon thrust to the east is consistent with our new reconstruction; 3) the Resting thrust probably does not link with the Shaw thrust, rather it appears to be truncated by the younger Gerstley Mine/Nopah Peak thrust and the hanging wall was eroded away or shifted east. Work in progress is further evaluating other thrusts in the system including the Montgomery Mountains, the Baxter Mine thrust, and the Wheeler Pass thrusts in adjacent ranges.