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| Titel |
A White Nile megalake during the last interglacial period |
| VerfasserIn |
Timothy T. Barrows, Martin A. J. Williams, Stephanie C. Mills, Geoff A. T. Duller, L. Keith Fifield, David Haberlah, Stephen G Tims, Frances M. Williams |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250093865
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| Publikation (Nr.) |
 EGU/EGU2014-9015.pdf |
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| Zusammenfassung |
| The eastern Sahara Desert of Africa is one of the most climatically sensitive areas on Earth,
varying from lake-studded savannah woodland to hyperarid desert over the course of a
glacial-interglacial cycle. In currently semiarid Sudan there is widespread evidence that a
very large freshwater lake once filled the White Nile River valley (Barrows et al., 2014). Here
we present the first quantitative estimate for the dimensions of the lake and a direct age for
the emplacement of its shoreline. Using a profile dating approach with the cosmogenic
nuclide 10Be, we estimate an exposure age of 109 ± 8 ka for this megalake, indicating that
it probably formed during the last interglacial period. This age is supported by
optically stimulated luminescence dating of Blue Nile paleochannels associated
with the lake. Using a high-resolution digital elevation model, we estimate that
the lake was more than 45,000 km2 in area, making it comparable to the largest
freshwater lakes on Earth today. We attribute the lake’s existence to seasonal flood
pulses as a result of local damming of the White Nile by a more southern position
of the Blue Nile and greatly increased precipitation associated with an enhanced
monsoon.
References
Barrows, T.T., Williams, M.A.J., Mills, S.C., Duller, G.A.T., Fifield, L.K., Haberlah, D.,
Tims, S.G., Williams, F.M., 2014. A White Nile megalake during the last interglacial period.
Geology. 10.1130/g35238.1 |
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