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The relationship between climate change and the development of Old World riverine civilizations is poorly understood because inadequate dating control has hindered effective integration of archaeological, fluvial, and climate records. This paper presents the most comprehensive and robustly dated archaeological and paleoenvironmental data sets yet compiled for the desert Nile. It focuses on the valley fl oor hinterland of the Kingdom of Kerma (2400?1450 B.C.) in northern Sudan. Kerma emerged as a rival to Egypt during Africa?s first ?Dark Age? drought. In contrast to other irrigation-based agriculturists in Egypt and Asia, Kerma flourished during the environmental crisis ca. 2200 B.C. We have studied the stratigraphy and archaeological records of paleochannels across an 80 km reach of the Nile upstream of Kerma using optically stimulated luminescence to date when channels fl owed and when they dried up. The dynamics of the local alluvial environment were critical in determining whether climatic fluctuations and changes in river flow represented an opportunity for floodwater farmers (5000?3500 B.C.), a hazard that could be managed (2400?1300 B.C.), or an environmental catastrophe that resulted in settlement abandonment (after 1300 B.C.).Peer reviewe

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Williams, M. A. J., Williams, F. M., Duller, G. A. T., Munro, R. H., El Tom, O. A. M., Barrows, T. T., Macklin, M. G., Woodward, J. C., Talbot, M. R., Haberlay, D., Fluin, J. (2010). Late Quaternary floods and droughts in the Nile valley, Sudan: new evidence from optically stimulated luminescence and AMS radiocarbon dating. Quaternary Science Reviews, 29(9-10), 1116-1137 Sponsorship: Australian Research Council;Our results show that the late Pleistocene Nile in northern Sudan was shifting position and actively aggrading at 145 +/- 20 kyr, 83 +/- 24 kyr, 32 +/- 8 kyr and 20.7 +/- 0.2 kyr and indicate, for the first time, a phase of high-energy flow in the White Nile at 27.8 +/- 3.2 kyr, with still high but somewhat reduced flow in that river at 13.3 kyr, 10 kyr and 4.8-4.0 kyr. Beach ridges associated with a 386 m strandline of the White Nile have OSL ages of 27.5 +/- 2.7 kyr and 14.5 +/- 1.6 kyr. The Holocene terraces and former channels of the main Nile have ages of 11 kyr, 6.5-5.0 kyr and 4.8-4.0 kyr, after which there was a general decline in flood discharge. The now arid main Nile valley in northern Sudan was significantly wetter during the early to middle Holocene, with a lake up to 450 km(2) in area, fed by an overflow channel from the early Holocene Nile between 9.5 kyr and 7.5 kyr. Previously stable late Pleistocene dunes were reactivated at intervals during the Holocene, with five samples from the White Nile valley indicating brief phases of Holocene dune activity at 9.9 +/- 2.0 kyr, 9.0 +/- 2.8 kyr, 6.6 +/- 0.9 kyr, 4.8 +/- 0.9 kyr and 2.9 +/- 0.5 kyr, the earliest of which occurred within periods of generally wetter climate and higher Nile flow. The youngest freshwater shells on the Khor Abu Habl alluvial fan west of the White Nile correspond to a time of regionally wetter climate between 1.7 and 1.0 kyr. Our results suggest that millennial scale climatic instability may have been characteristic of Holocene climates in this region. (C) 2010 Elsevier Ltd. All rights reserved.Peer reviewe

Landsat 5 Thematic Mapper and 7 Enhanced Thematic Mapper imagery reveal lake shorelines in the White Nile valley as far south as lat 10؇N. The highest shoreline is at 386 m elevation and was eroded when the White Nile formed a lake as wide as 70 km and Ͼ500 km long. Finely laminated green clays laid down on the floor of this lake are overlain by alluvial sands and clays, dated by optically stimulated luminescence as 15 ka to older than 250 ka. The alluvium was deposited during interglacial episodes of stronger summer monsoons and very high White Nile floods. The White Nile paleolake is much older than marine oxygen isotope stage 7 and may have formed ca. 400 ka, during the exceptionally long stage 11 interglacial.