Quaternary Geochronology: Eastern Sahara and American West

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Previous NSF-sponsored research in the hyperarid eastern Sahara has established a discontinuous geochronological sequence spanning the Quaternary. Early to Middle Pleistocene alluvium and eolian sediments with Early Paleolithic archaeology in buried "radar" valleys are inset by lacustrine deposits associated with Middle Paleolithic archaeology. These are overlain by Holocene sand sheets, playa deposits, and laminated lake beds with associated Neolithic archaeology. Paleoclimatic and paleo- environmental interpretations based upon geology, archaeology, fauna, and palynology indicate major north-south fluctuations of the Sahelio-Saharan transitions zone during late Quaternary time. The Meidob Hills, a basaltic volcanic pile, periodically active for perhaps the past 30 millions years, lies on the present southern fringe of the Sahara and has, therefore, experienced the passage of the transition zone back and forth several times. With the collaboration of an interdisciplinary team I propose to study alluvial and eolian sediments interbeded with datable volcanics to establish a time-calibrated strati- graphic sequence that will be correlatable to strata of the hyperarid core of the Sahara as well as southward to African rift valley sequences. The results will be of value in understanding past man-land relationships in the sensitive Saharan fringe in order to better assess future land uses and also in comparing hyperarid geomorphic processes with semiarid American West. Investigative techniques include stratigraphy, sedimentology, palynology, AMS radiocarbon dating, space imagery remote sensing, isotope geochemistry, and archaeological observations. The possibility for early hominid remains will not be overlooked.