The Middle Stone Age After 50,000 Years Ago: New Evidence From the Late Pleistocene Sediments of the Eastern Lake Victoria Basin, Western Kenya

Abstract

Here we report tephra correlations, lithic artifacts, obsidian sourcing data, and fauna from nine Late Pleistocene localities of the eastern Lake Victoria basin of western Kenya, as well as new excavations from the 49–36 ka site of Nyamita Main on Rusinga Island. The Late Pleistocene of Africa is an important period for the evolution and dispersals of Homo sapiens. A conspicuous behavioral feature of this period is the replacement of Middle Stone Age (MSA) technologies by Later Stone Age (LSA) technologies. Current research shows this process is complex with the LSA appearing and the MSA disappearing at different times in different places across Africa. Account-ing for this pattern requires a precise chronology, detailed evidence of past human behavior and environmental reconstructions of the appropriate scale. Data presented here provide this detail. Tephra correlations improve the regional chronology and expand the lateral area of Late Pleistocene eastern Lake Victoria basin exposures from ~650km2 to >2500km2. Lithic artifacts show MSA technology is present younger than 36 ka in western Kenya, 25–35 kyr younger than the first appearance of early LSA technology elsewhere in equatorial East Africa. Obsid-ian sourcing data presented here shows the use of the same raw material sources by MSA and LSA populations through long periods of time from >100 ka through <36 ka. The methods employed here provide the temporal resolution and appropriate geographic scale to address modern human behavioral evolution.