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.