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

Abstract

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. © 2004 Wiley Periodicals, Inc.

Levallois Lithic Technology from the Kapthurin Formation, Kenya: Acheulian Origin and Middle Stone Age Diversity

“…Within the Atlantic coastal Moroccan sequence, Levallois production of handaxe and cleaver blanks is described from Biberson's (1961) "Middle Acheulian," now dated to ∼ 300-350 ka by bracketing ESR age estimates at the Grotte des Rhinocéros and by OSL at Cap Chatelier (Raynal et al, 2001;Rhodes et al, 1994). A similar age is estimated for rare examples of handaxes transformed into Levallois or Levallois-like cores from the mound-spring site of KO10 at Kharga Oasis, where U-series dates on tufa of ∼ 300-400 ka are reported (Caton-Thompson, 1946, 1952Churcher et al, 1999;Smith et al, 2004). 40 Ar/ 39 Ar dates indicate a minimum age of 157 ka for handaxes and cleavers made on Levallois flakes from the Upper and Lower Herto Members of the Bouri Formation in the Middle Awash of Ethiopia, apparently associated with fossils attributed to Homo sapiens (de Heinzelin et al, 2000;Clark et al, 2003).…”

Holocene Supra-Regional Environmental Changes as Trigger for Major Socio-Cultural Processes in Northeastern Africa and the Sahara

“…The most recent development of palaeoenvironmental studies over North Africa is due to the massive introduction of radiometric methods ( 14 C, U/Th, cosmogenic nuclides and luminescence methods) to date palaeohydrological archives, which permitted the definition of time and steps of main climatic trends and the identification of rapid climatic events. Moreover, a fundamental role in palaeoenvironmental reconstruction was played by the introduction of geochemical investigation of stable isotopes (C and O) in lake sediments, spring tufa, soil horizons and animal remains (e.g., Johnson et al 1993;Abell and Hoelzmann 2000;Hoelzmann et al 2001Hoelzmann et al , 2010Lamb et al 2002;Smith et al 2004;Zerboni 2006;Cremaschi et al 2010;Terwilliger et al 2011;Zerboni and Cremaschi 2012;di Lernia et al 2013;Barrows et al 2014). Fig.…”

Micromorphological approach to polycyclic pedogenesis on the Messak Settafet plateau (central Sahara): Formative processes and palaeoenvironmental significance

“…Analyzing the rate of accumulation of subsequent members from the lacustrine Al Mahruqah Formation (in the Murzuq-Shati area), they noticed a trend of shrinking lake size across the Quaternary, even more pronounced in the Late Pleistocene and Early Holocene. This phenomenon is interpreted as a reduction of intensity of the humid episodes, especially comparing the Holocene wet phase with those occurring in the Pleistocene; it found further confirmation in the general decrease in the rate of lacustrine limestone sedimentation in eastern North Africa from one humid episode to the next during the Upper Quaternary (Szabo et al, 1995;Smith et al, 2004;Brookes, 2010). …”