The volcanic rock spheres of Melka Kunture (Upper Awash, Ethiopia) at Gombore IB and later Acheulean sites

Abstract

Rock spheres have been discovered at several prehistoric sites of Melka Kunture in the volcanic surroundings of the Upper Awash in the Ethiopian highlands. The paper describes those found at eight Acheulean sites spanning more than one million years, from Gombore IB (1.7 Ma or earlier) to Garba I (0.6 Ma), providing detailed metrical information. Contrarily to those from other Pleistocene localities, the spheres of Melka Kunture are not the endproduct or byproduct of anthropic activity, but rather carefully selected natural shapes of volcanic origin, i.e. lavas and accretionary lapilli. The spherical rocks and lapilli were picked by Homo erectus and later by Homo heidelbergensis from outcrops or secondary deposits which varied through time. Likely battered marks and abraded surface planes could be result of percussion activities.