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Reconstruction of a semi-arid late Pleistocene paleocatena from the Lake Victoria region, Kenya

Published online by Cambridge University Press:  20 January 2017

Emily J. Beverly*
Affiliation:
Terrestrial Paleoclimatology Research Group, Department of Geology, Baylor University, One Bear Place #97354, Waco, TX 76798-7354, USA
Steven G. Driese
Affiliation:
Terrestrial Paleoclimatology Research Group, Department of Geology, Baylor University, One Bear Place #97354, Waco, TX 76798-7354, USA
Daniel J. Peppe
Affiliation:
Terrestrial Paleoclimatology Research Group, Department of Geology, Baylor University, One Bear Place #97354, Waco, TX 76798-7354, USA
L. Nicole Arellano
Affiliation:
Terrestrial Paleoclimatology Research Group, Department of Geology, Baylor University, One Bear Place #97354, Waco, TX 76798-7354, USA
Nick Blegen
Affiliation:
Department of Anthropology, University of Connecticut, U-2176, Storrs, CT 06269, USA
J. Tyler Faith
Affiliation:
School of Social Science, University of Queensland, Brisbane, QLD 4072, Australia
Christian A. Tryon
Affiliation:
Department of Anthropology, Harvard University, Peabody Museum, 11 Divinity Ave., Cambridge, MA 02138, USA
*
*Corresponding author.Email Address:[email protected]

Abstract

The effect of changing environment on the evolution of Homo sapiens is heavily debated, but few data are available from equatorial Africa prior to the last glacial maximum. The Karungu deposits on the northeast coast of Lake Victoria are ideal for paleoenvironmental reconstructions and are best studied at the Kisaaka site near Karunga in Kenya (94 to > 33 ka) where paleosols, fluvial deposits, tufa, and volcaniclastic deposits (tuffs) are exposed over a ~ 2 km transect. Three well-exposed and laterally continuous paleosols with intercalated tuffs allow for reconstruction of a succession of paleocatenas. The oldest paleosol is a smectitic paleo-Vertisol with saline and sodic properties. Higher in the section, the paleosols are tuffaceous paleo-Inceptisols with Alfisol-like soil characteristics (illuviated clay). Mean annual precipitation (MAP) proxies indicate little change through time, with an average of 764 ± 108 mm yr− 1 for Vertisols (CALMAG) and 813 ± 182 to 963 ± 182 mm yr− 1 for all paleosols (CIA-K). Field observations and MAP proxies suggest that Karungu was significantly drier than today, consistent with the associated faunal assemblage, and likely resulted in a significantly smaller Lake Victoria during the late Pleistocene. Rainfall reduction and associated grassland expansion may have facilitated human and faunal dispersals across equatorial East Africa.

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Articles
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University of Washington

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