New light on the age of the White Nile
- 1Geographical and Environmental Studies, University of Adelaide, Adelaide, South Australia 5005, Australia
- 2School of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
- 3Department of Physics and Mathematical Physics, University of Adelaide, Adelaide, South Australia 5005, Australia
Abstract
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 >500 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.
Footnotes
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↵* Deceased
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- Accepted August 15, 2003.
- Received May 5, 2003.
- Revision received July 29, 2003.
- Geological Society of America
