Increased age estimate for the Lower Palaeolithic hominid site at Olorgesailie, Kenya

Abstract

The Acheulean is the major stone-tool tradition of Africa, and of much of Asia and Europe, which lasted in Africa from ∼1.5 to 0.15 Myr BP. It is associated with Homo erectus at some sites, and is characterized especially by hand-axes. Cultural development within the Acheulean has been very hard to assess because so few sites can be dated. Here we report potassium–argon dates and geochemical correlation of tephra layers at Olorgesailie—a key Acheulean site in the Kenya rift valley. The results suggest that the upper part of the Olorgesailie Formation lies between 0.6 and 0.74 Myr BP, and that the maximum age is ∼0.9 Myr. Most of the artefact-bearing levels at this site are thus >0.70 Myr old, significantly older than formerly thought.