Dating method glaciation
The study area extended from the alluvial fans of Owens Valley west to the Sierra crest from latitude 36°45' N to 37°00' N.It included the southern part of the Big Pine volcanic field, an eruptive center for basaltic lavas for most of the Pleistocene Epoch.The focus was on Pleistocene moraines near the range front.The motivation of this research was to improve our understanding of the chronology of Pleistocene events, to characterize details of the tectonic history of the Sierra, to infer faulting, erosion, and deposition rates, and to provide a basis for the comparison of the Quaternary geology in the southeastern Sierra and in more intensively studied regions in the central and northern Sierra and elsewhere.The youngest glaciers (Matthes glaciation) left unconsolidated and unvegetated till in stagnant rock glaciers and moraines in cirques on high peaks. Extending out from the cirques and into the upper reaches of the canyons are moraines correlating to the Recess Peak glaciation.Till is generally consolidated and supports heavy lichen growth and bushes but few trees.Traces of at least seven glaciations were found during this study.Moraines and other deposits left during these glaciations could be distinguished based on the degree of weathering of granitic clasts, vegetative cover, and morphologic characteristics.
The main goals of this thesis were the detailed mapping of Quaternary glacial and other deposits in these regions, dating of critical events, and geomorphic analysis of the range front.The foothill blocks are identical to the Sierras in composition.Below the foothills coalescing alluvial fans grade a few km east to the alluvium and lacustrine sediments of the Owens River and Owens Lake.The Hilgard glaciation may have simply been the last stade of the Tioga glaciation from the evidence found in this study.At least four Pleistocene glaciations occurred in the southeastern Sierra Nevada.
The southeastern Sierra Nevada consists of three geographic regions.