| Popis: |
The function of early Oldowan tools is still a main research question in the field of Early Stone Age in eastern Africa. The rarity of the sites, the preservation of the assemblages and raw materials are limiting factors in the functional study of assemblages older than 2 million years. The archaeological occurrences from the Member F of the Shungura Formation (Lower Omo Valley, Ethiopia) have a precise chronological frame (2.324± 0.020 Ma to 2.271 ± 0.041 Ma), a detailed stratigraphy of successive fluvial deposits and artefacts produced mainly from small quartz pebbles that are highly resistant to chemical and mechanical alterations. In order to evaluate the preservation of use-wear, we implemented a multi-scale taphonomic analysis using size sorting, macroscopic and microscopic surface alterations. In addition, post-depositional surface modification experiments on quartz material are scarce. Therefore, fluvial and aeolian experiments were set up to characterized the wear produced by fluvial transport and aeolian abrasion on the ground. The studied archaeological material comprises 1033 artefacts from 12 occurrences and three environmental contexts (floodplain, point bar and channel lag). Despite the good preservation of the lithic assemblage at a macroscopic scale, there is a nuance at a microscopic level and a variability of wear according to the contexts. Understanding the taphonomic alterations on quartz and making a link with the type of deposits lead to a better recognition and interpretation of the use-wear found on the material. |
