Using Paleosols to Reconstruct the Paleoenvironment and Paleoclimate of a Late Pleistocene Archaeological Site in the Lake Victoria Basin, Kenya

Abstract

Since its formation >400,000 years ago Lake Victoria has expanded and contracted in response to climate change, but little data are available prior to the Last Glacial Maximum during an important interval in human evolution when modern humans dispersed across equatorial East Africa. This study uses paleopedology to reconstruct the paleoenvironment during the Late Pleistocene and focuses on three paleosols from Kisaaka, a site near Karungu, Kenya along the eastern margin of Lake Victoria. The oldest is a paleo‐Vertisol, overlain by two paleo‐Inceptisols. Bulk and clay mineralogy indicate that smectite dominates the paleosols. Bulk geochemistry of the paleosols was used to understand weathering and estimate mean annual precipitation (MAP) of ~700 to 900 mm/yr using the CALMAG and CIA‐K weathering indices. Field observations, mineralogy, and MAP estimates from Kisaaka paleosols suggests a seasonally dry, open grassland environment during the Late Pleistocene in Lake Victoria that is very different from the closed bushland and forest habitats historically present in the region.