Friday, April 13, 2012

Climate at the end of the Pleistocene on the Egyptian Nile

Excerpted from "Foraging and Farming in Egypt" by Wilma Wetterstrom from The Archaeology of Africa edited by Thurston Shaw, Paul Sinclair, Bassey Andah and Alex Okpoko (Link)

"It is impossible to understand ancient, or modern, Egypt without considering the Nile and its profound influence on plant and animal life.  Flowing north-northwest, the Nile has incised a narrow river valley through pleistocene sands and gravels.  Just north of Cairo, it fans out across the wide expanse of delta, channelled today into two branches.  Through most of its Egyptian course, some 800 km from the Sudanese border to Cairo, it is virtually the only source of water.  The floodplain, now carpeted with acres of irrigation fields, varies widely along the length of the Nile; near Aswan it is little more than the width of the river.  Further downstream it is broader, reaching up to 23 km in some places (Issawi 1976).  Thus the potential for foraging and farming varied markedly through the river valley."

   "Skirting the river's floodplain are the low desert terraces, with cliffs rising above them.  Beyond lie the deserts:  to the east is the Eastern Desert with low rugged mountains, steep scarps and valleys; on the opposite side of the river lies the Western Desert, a flat monotonous plain, barren except for several oases (Issawi 1976)."

   "The climate today is hyperarid, with practically no precipitation south of the Delta except for occasional rain in the Red Sea hills (Issawi 1976).  But this was not always the case.  Egypt has seen climatic changes and important alterations in the river regime over the last 20,000 years.  The period from 20,000 to 12,000 BP was hyperarid, like the present, but cooler.  At the end of the Pleistocene as the glaciers retreated, rainfall and temperature increased (Wendorf & Schild 1989, pp. 768-88). Rainfall levels remained higher through much of the early to mid-Holocene, which saw three moist phases.  Drier conditions started about 5400 BP and have continued to the present (Wendorf & Schild 1980, pp. 236-41; see also Grove, Ch. 1, and Maley, Ch. 2, this volume)."

   "Partly as a result of these climatic changes, the Nile has had a complex geological history.  The river has at various times built its floodplain and at others cut it down, as its water volume and sediment load have varied.  This has undoubtedly had far-reaching consequences for the archaeological record in the Nile valley.  For example, these geological processes may be responsible for the void in the record for the Nile valley north of the Qena bend.  There are no sites in this region [in the Nile valley] between upper paleolithic and predynastic times, although it is hard to imagine that this potentially rich area would have been ignored by holocene foragers."

   Editors' note:  "In the Sohag-Abydos region just north of the Qena bend a few in situ middle and upper paleolithic sites have been located, but all of these are preserved in wadis outside the Nile valley or are on protected terraces high above the valley floor (Paulissen & Vermeersch 1987, pp. 32, 34, 37-8, 40)."

References:

Isawi, B.  1976.  An introduction to the physiography of the Nile valley.  In Prehistory of the Nile Valley, Windorf, F. & R. Schild (eds.), 3-22.  New York:  Academic Press.

Paulissen, E. & P. M. Vermeersch 1987.  Earth, man and climate in the Egyptian Nile valley during the Pleistocene.  In Prehistory of Arid North Africa:  essays in honor of Fred Wendorf, Close, A. E. (ed.), 29-67.  Dallas:  Southern Methodist University Press.

Wendorf, F. & R. Schild 1980.  Prehistory of the Eastern Sahara.  New York:  Academic Press.

Wendorf, F. & R. Schild 1989.  The Prehistory of the Wadi Kubbaniya, Vols 2 & 3:  Stratigraphy, Paleoeconomy, and Environment and Late Palaeolithic Archaeology.  Dallas:  Southern Methodist University Press.

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