Late Quaternary Valley Fills and Paleoenvironments of the Southern High Plains

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The research examines late-Quaternary sediments on the Southern High Plains for information on past environments. A number of dry valleys (draws) cross the region and have slowly filled with sediments for the past +11,000 years. Previous scattered geomorphic investigations strongly suggest synchroneity in late Quaternary depositional and soil-forming events and similar regional environmental changes. The first objective of the research is to document the late Quaternary stratigraphic histories of the draws to test the hypothesis of synchronous, regional geomorphic and soil-forming events. Another objective is to understand environmental and hydrologic changes at the end of the Pleistocene. There are marked out-of-phase hydrologic changes from flowing to standing water along and among the draws between 11,000 and 10,000 yrs. B.P. It is unclear whether these variations are due to local geomorphic conditions or environmental differences. The third objective is aimed at understanding middle Holocene environments. There appears to have been regional, massive eolian deposition at this time, suggestive of severe widespread aridity. The proposed research will help establish the late Quaternary paleoenvironmental record for a vast region (over 120,000 km), hitherto known only from a few sites. The record appears to be one of dramatic environmental changes, which is clearly the case for historic times. Understanding these past changes could help in dealing with future climatic extremes.