Paleoanthropological mission to the Omo river lower valley
• The Paleo- anthropological Mission to the Omo i.e. the Omo Group Research Expedition, carried out a new field mission to the lower valley of the Omo River,in the south-west of Ethiopia, the SNNPR region, from 6 June to 23July2010 ,under the leadership of Jean-Renaud Boisserie (CFEE). About twelve European scientists made up of French and Belgians, together with some Americans, participated in the field and laboratory work. The mission brought together more than thirty participants in all. The paleontological and archaeological research was carried out on the Shungura mountains dated between 3,6 million years (My) and 1 My.
A series of new paleontological sites was discovered in the Shungura mountains .The sites date back to between 1,4 million years (My) and 1 My, a particularly ignored period of the evolution of the African continent. First among all previous researches, it uncovered hundreds of fossils, including skeletal-dental remains and post-skeletal Hominides resembling Homo erectus.
The fossil biodiversity of these sites is quite peculiar in its composition, including several species unknown elsewhere. This buttresses the assumption that it was isolated from the Lake Turkana basin after 2 My and that, that isolation may have been triggered by an elevation phase in the margins of the rift valley as well as a major volcanic event. It may have resulted from the barriers filtering or even temporarily blocking faunal exchanges with other African basins, including the neighbouring Konso region .
That barrier seems to have also affected technologies, the stone industry being practically absent from those levels, in spite of the presence of Hominides producing highly sophisticated tools elsewhere in Ethiopia. This reinforces the idea of a human evolution catalysed by a multitude of environmental parameters, and not only by climate.
The rest of the paleontological operations was carried out on levels dated between 3 My and 2.5 My, as well as in the neighbourhood of 1.8 My, allowing for the discovery of several specimens of Hominides close to the Australopithecus and the first representatives of the Homo kind. Altogether, more than one thousand fossils were collected this year and are in the process of being analysed at the National Museum of Ethiopia. The archaeological Work focused on a level dated on 2.3 My and on older levels. The work also included prospecting phases, stratigraphic location and surveys.
Many new archaeological occurrences were discovered around 2.3 My. Sometimes they showed a stone industry on quartz in association with fauna. These occurrences document a major density of landscape occupation by Hominides, a situation previously unknown before 2 My. From that period onwards, a systematic selection of worked materials was carried out, because quartz represented only a fraction of the raw materials available on the Shungura mountains as could be documented much earlier than this year.
This intense activity of Hominides in the lower valley of the Omo river seems to have lasted at most, one thousand years and was then apparently interrupted for reasons not immediately understood. The work of a very precise positioning of the sites over time and their deposit environments which started this year, will in the long run, make it possible to understand the factors that influenced this activity and the industry that testifies to it, among the richest and the oldest in the world.