Geological origin of the archaeological obsidian artifacts from the Holocene sequences of Mochena Borago and Yabello, southern Ethiopia

Abstract

Obsidian archaeological artifacts from the Holocene occupation sequences at the contemporary sites of Mochena Borago and Yabello, southern Ethiopia, have been characterized using electron microprobe analysis. Results show the artifacts of each site were partially procured from two separate but known sources, Bantu and Chebe. The inhabitants of both sites also seem to have used obsidian from another, as yet unknown, source. This is interesting as the inhabitants of each site pursued different life ways: one entirely dependent on wild animals and the other incorporating domestic fauna. In spite of the analysis of many geological sources in the Ethiopian Rift System, the unknown sources cannot yet be determined. Despite erupting from several vents, one of the sources, Chebe, has uniform elemental chemistry, representing an exception to the widely held assumption that every eruptive sequence has unique chemistry, the archaeological significance of which should be further explored.