A reconstruction of Quaternary pluvial environments and human occupations using stratigraphy and geochronology of fossil-spring tufas, Kharga Oasis, Egypt

We carried out a geologic survey and a preliminary archaeological survey of four fossil-spring tufa localities in Kharga Oasis, Egypt, to constrain the timing of pluvial episodes in the Western Desert, and to document prehistoric occupation contemporaneous with times of increased rainfall. Uranium-series dating of the tufas confirms that at least five episodes of tufa deposition are represented in Kharga, although not every event is represented at each locality. Across the region studied, tufas were most frequently deposited as part of a fluvial barrage system, characterized by terraced, vegetated pools impounded by arcuate tufa dams and separated by small waterfalls. Available water resources during pluvial phases would have included not only spring-fed streams but also small freshwater lakes. While Earlier Stone Age (ESA) and Middle Stone Age (MSA) lithic artifacts may be found either as surficial lags on tufas, or, less commonly, encased within tufas, Epipalaeolithic and Neolithic artifacts are generally found in or on silts within surface deflation depressions in the tufas, principally at Wadi Midauwara.