Geochronology and climate change of the Pleistocene-Holocene transition in the Darb el Arba'in Desert, Eastern Sahara

Abstract

More than 25 years of geoarchaeological investigations in the hyperarid regions of southwestern Egypt and northwestern Sudan, the Darb el Arba'in desert, demonstrate that Holocene pluvial conditions began about 9800 yr B.P., essentially at the end of Younger Dryas cooling. The eastern Sahara changed from a hyperarid, lifeless desert dominated by eolian activity and deflation to an arid to semiarid savanna that attracted Sudano‐Sahelian fauna and Neolithic pastoralists to the region until about 5000 yr B.P., when the current episode of hyperaridity ensued. In the lake and playa basins of the eastern Sahara, Younger Dryas time, about 10,800–9700 yr B.P., is represented by an erosional hiatus, during which deflation of basins occurred. The only deposition that may have occurred during this hyperarid period is sand sheet aggradation and dune formation consistent with the Sahara being hyperarid during the glacial periods. Younger Dryas‐age eolian deposits have yet to be identified by optically stimulated luminescence (OSL). The current hyperaridity would imply that glacial conditions exist in the northern hemisphere, yet the opposite is the case. Perhaps global glaciation lags the onset of Saharan hyperaridity by several millennia, and the area is in a transitional phase much like the Bølling and Allerød periods. © 2001 John Wiley & Sons, Inc.

Assessment of waterlogging in agricultural megaprojects in the closed drainage basins of the Western Desert of Egypt

“…pluvial), which developed fluvial channels, lacustrine deposits in local depressions, and more significantly have replenished the groundwater aquifers (Nicoll, 2004). Most of the evidence of preceding wet phases and the alluvial channels have widely been obliterated by the erosion and aeolian deposits (McCauley et al, 1982;Haynes, 2001;Pachur and Hoelzmann, 2000). Typical dryland closed drainage basins in the Western Desert of Egypt (the depressions of Baharia and Farafra Oases), were selected to assess the interaction of different landforms, the hydrogeological setting and the agricultural management on the land degradation of cultivated areas.…”

Early North African Cattle Domestication and Its Ecological Setting: A Reassessment

“…2a, b (Kuper and Kröpelin 2006), the ecology underwent a change from hyper-arid to semi-arid conditions (Brooks 2005). The ITCZ belt shifted c. 250 km northwards in the second half of the tenth millennium BC (Haynes 2001); eventually, the isohyets shifted northwards by 400-550 km (Nicoll 2004;Ritchie and Haynes 1987;Wickens 1982, p. 25). By c. 8500 BC, the Sahelian semi-desert zone had advanced up to the 24°N latitude (Kuper and Kröpelin 2006), while Neumann (1989) states that summer rainfall occurred from the 22°latitude southwards.…”

“…Their water came from local recharging of the water tables, which caused them to rise above the new depressed ground level (Haynes 2001), or were sheetwash lying on top of the water table a couple of metres below ground level. Nabta Playa and, in particular, Bir Kiseiba, are examples of the former (Issawi and el Hinnawi 1984), and their water varied in intensity and volume affecting the extent of available vegetation cover.…”

“…Nor did their paper, or the Combined Prehistoric Expedition's faunal reports (Gautier 1984), look at the stratigraphical distribution of the cattle bones from the area and their associated radiocarbon dates. I turn to the original geological report (Issawi and el Hinnawi 1984) to argue that more water was present on the surface during the early Holocene than acknowledged in the early cattle domestication model, and draw upon additional geological reports (Haynes and Haas 1980;Haynes 2001), which have been little cited in the debate, in support. I also draw upon comparisons with other archaeological and modern semiarid regions to refute the claim that the ecology of the Nabta Playa-Bir Kiseiba area during the early Holocene was capable of supporting only small game animals and gazelle, which is the underpinning of the early cattle domestication model Wendorf et al 1984;Wendorf and Schild 1994).…”

Saharan Rock Art: Local Dynamics and Wider Perspectives

“…In particular, the onset of the Holocene was characterized by a period of high rainfall, due to the northward migration of the Intertropical Convergence Zone, resulting in the expansion of the summer monsoon [1,[65][66][67][68][69][70], possibly coincident with a southern movement of the Mediterranean winter rainy system [71], causing the recharge of the aquifers and the reactivation of springs, rivers and lakes. During this period, known as the African Humid Period, the establishment of a more humid environment and the presence of savannah vegetation cover [72] allowed the human reoccupation of the massifs, first by Epipalaeolithic and Mesolithic hunters and gatherers (locally known as Early Acacus and Late Acacus cultures), and later by Pastoral communities [2,62,73].…”