Document Type

Article

Publication Date

11-20-2007

Abstract

North-western Sudan, as a part of the castern $ahara, is among the dricst places on earth. However, the region underwent drastic climatic changes through alternation of dry and wet conditions in the past. During humid phases, wher rain was plentiful over a prolonged time period, the surface was veined by rivers and dotted by large lakes, The new Shuttle Radar Topography Mission data SRTM ~90 m) revealed a large endorheic drainage basin, which is centred by a large terminal palaeolake, in the northern Darfur State. The use of GIS methods allowed the delineation of the drainage basin and its associated palacorivers, The SRTM datu along with thc Landsat (ETM+) and Radarsat-l images corroborate the preserce of segments of palacoshorelines associated with the palaeolake highstands. These constitute a convincing argument of the long-tcrm existence of a possible pre-Holocene large water body in the region in the past. The remains of the hnighest palacoshoreline have a coustant altitudc of $73+3 m as. At its maximum extent, the mega Lake occupied an area of `about 30 750 kin?-- (the same size as the Great Bcar Lake. Canada's lareest lake), which would have contained approximately 2530 km> of water. This, ancestral take, which we named the Northern Darfur Megalake (ND Megalake), represents indisputable cvidence of the past pluvial conditions in the eastern Sahara. The discovered palaeoshorelines will have significant consequences for improving our knowledge of continental climate change and regional palaeohydorology, and should be taken into consideration in studies of past human habitation in the region. Much of the water carried by the Northern Darfur palaeorivers and the ND Megalake would have percolated into the underlying rocks feeding the Nubian Sandstor aquifer. These findings show that the used approach of space-data integration can help significantly in the groundwater exploration efforts in the Darfur region, where freshwater access is essential for refugee survival, and can be successfully adopted in other parts of Sudan and arid lands in general

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