2.6-Million-year-old stone tools and associated bones from OGS-6 and OGS-7, Gona, Afar, Ethiopia
Context: This article aims to investigate the context in which the oldest stone artifacts have been found, presenting findings from two new sites in Ouda Gona, Afar, Ethiopia. Specifically, it investigates the raw materials used to create the artifacts and the associated bones found at OGS-6 and OGS-7. These sites sit about 300 meters apart from one another, and have been dated to about 2.6 Myr.
Methods and Materials: Chronology was determined on both sites through a combination of 40Ar/39Ar dating on the volcanic tuff that sits above the site and the geomagnetic polarity of the stratigraphy. The artifacts found at OGS-7 were compared with cobbles found in an excavation of the palaeo-banks of the Awash River. The compositions of these two samples were compared in order to statistically determine how similar the materials were. Bones were examined in terms of if there were human modifications done to them.
Results: The comparison of the cobbles from the Awash and the artifacts at OGS-7 showed that they were different in character. Most of the materials used to create the artifacts were finer-grained than those of the available cobbles. The materials used at OGS-7 are much more fine-grained than those collected from the surrounding area. The debitage of OGS-7 also were much higher in chert than the cobble samples, however no cores comprised of chert were found. This has led to the conclusion that hominids at OGS-7 were highly selective in the materials used to create stone artifacts, specifically not relying on the ample supply of rocks provided at the banks of the river. The presence of cut-marks found at bone at OGS-6 and clustering of bone fragments at OGS-7 are attributed to the use of these stone tools to butcher and process animals.
Theoretical and practical relevance:
These findings, along with others from the sites in this region are crucial to the understanding of the context surrounding the earliest stone artifacts. This paper supports the idea that the earliest stone artifacts were used to process animals for meat. These findings also have implications for the creators of the artifacts themselves. The discernment of the quality of material to create stone tools at this site might be able to support a claim that the hominids that created these tools had a mental capacity greater than that seen in non-human primates today.