Late Pliocene archaeology of the Gona River deposits, Afar, Ethiopia

The timing, context and paleoecological settings for the beginning of the manufacture and use of flaked stones is one of the critical questions in palaeoanthropology. More than 3,000 artifacts have been recovered through survey and excavations undertaken between 1992-1994 at Gona. A combination of radioisotopic and paleomagnetic dates provided a secure age of between 2.6-2.5 million years (mya) for the artifacts. The makers have yet to be identified, but they had excellent knapping skills, and a clear understanding of conchoidal fracture mechanics. This thesis provides a detailed description and analysis of the Gona artifacts. Technologically, they are similar to Olduvai Gorge assemblages (1.7-1.8 mya) assigned to the Oldowan Industry.;A new 'Industrial Complex' (the Omo) and two 'facies' (the Shungura and the Nachikui) have been proposed for the 2.3-2.4 mya artifacts recovered from Omo (Ethiopia), and from Lokalalei (Kenya). Sometimes, all the Late Pliocene artifacts are also referred to as the "Pre-Oldowan", to differentiate them from the Oldowan of Early Pleistocene. The authors who proposed the new facies and industry argue that the hominids responsible for making the Late Pliocene artifacts lack understanding of conchoidal fracture mechanics, and lack the ability to remove complete flakes from cores. A majority of the Gona artifacts (70%) were made of trachyte, the most abundant raw material from nearby ancient stream channels. The raw materials from Omo (small quartz pebbles) and Lokalalei (lava) differ from Gona. Experimental work is essential to determine the flaking qualities and the role played by the various raw materials represented at these sites.;The well-flaked nature of the cores, the clear understanding of the flaking properties of the raw materials by the makers of the Gona artifacts, does not support the presence of a different stone industry prior to 2.0 mya, other than the Oldowan as originally defined by M.D. Leakey (1971). It is argued in this thesis that the Oldowan Industry appeared ca. 2.6 mya, and remained unchanged, until a new industry, the Acheulean, took over ca. 1.5 mya, suggesting a technological stasis of a million years for the Oldowan.