Onset of the African Humid Period by 13.9 kyr BP at Kabua Gorge, Turkana Basin, Kenya

Abstract

The shift toward wetter climatic conditions during the African Humid Period (AHP) transformed previously marginal habitats into environments conducive to human exploitation. The Turkana Basin provides critical evidence for a dynamic climate throughout the AHP (~15–5 kyr BP), as Lake Turkana rose ~100 m multiple times to overflow through an outlet to the Nile drainage system. New data from West Turkana outcrops of the late-Pleistocene to early-Holocene Galana Boi Formation complement and extend previously established lake-level curves. Three lacustrine highstand sequences, characterized by laminated silty clays with ostracods and molluscs, were identified and dated using AMS radiocarbon on molluscs and charcoal. This study records the earliest evidence from the Turkana Basin for the onset of AHP by at least 13.9 kyr BP. In addition, a depositional hiatus corresponds to the Younger Dryas (YD), reflecting the Turkana Basin’s response to global climatic forcing. The record from Kabua Gorge holds additional significance as it characterized the time period leading up to Holocene climatic stability. This study contributes to the paleoclimatic context of the AHP and YD during which significant human adaptation and cultural change occurred.