9316443 Wells Climate variations and hydrologic responses are recorded in numerous sedimentologic and geomorphic features, including lacustrine sequences and fluvial landforms. Pleistocene Lake Manly in Death Valley was the end point for river discharges during the Quaternary. The supply of runoff was from three major sources: The Owens River system draining the eastern slopes of the Sierra Nevada in response to glacial meltwaters, the Mojave River draining the San Bernardino Mountains in response to precipitation due to orographic uplift over the Transverse Ranges, and the Amargosa River which heads in the lower Black and Timber Mountains. Presently, the Amargosa is the only river to flow into Death Valley. This project will address 1) how the Amargosa River acquired its surface flow, from anamolous climatic conditions, or from groundwater, and 2) the relative role the Amargosa River discharge has in contributing to lake-building events in Death Valley during the late Quaternary. Understanding the geomorphic and hydrologic evolution of the Amargosa River system is important for the following reasons; (1) It contributions a significant 15,540 Km2 to the total potential drainage area of Death Valley in the late Quarternary (Hunt et al., 1966) (2) Amargosa River surface runoff comes from a low-elevation drainage system that may serve as a paleoclimatic indicator of late Quaternary climatic regimes unaffected by glaciation or high elevation orographic precipitation. (3) The drainage basin of the Amargosa River lies on the periphery of climatic/physiographic zones where it has the potential to indicate large-scale climatic fluctuations preserved in fluvial/lacustrine sediments. (4) it drains the potential site of the nations's proposed high-level radioactive waste repository at Yucca Mountain, Nevada. We propose to (a) reconstruct the late quaternary flood history of the Amargosa River (b) determine the modern hydrologic and climatic conditions for floo ding (c) reconstruct late Quaternary lake-building events in Death Valley and (d) the late Quaternary flood histories of the major drainages and their relationship to paleoclimate dynamics. ***
