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2017-11-02 15:32:32   •   ID: 1678

An Oldowan Tool from the lower Omo Valley

Figure 1
This is a chopping tool / bifacial core from the lower Omo Valley in Ethiopia made from a quartz pebble  (maximal diameter: 7 cm).

All  studies from this location, published so far, point out that the early lithic artifacts, found in situ, are mainly made from quartz pebbles similar to the example shown here.

Figure 2
Pioneering research in the Lower Omo Valley was early initiated by Arambourg in 1933, and was continued by the International Omo Research Expedition between 1967 and 1976.

These expeditions have produced one of the best-documented bio-environmental and chronostratigraphic Plio-Pleistocene records for the study of human and faunal evolution.

Fortunately, the transdisciplinary Omo Group Research Expedition project is continuing. Beginning with the 1970ies, very old lithic ensembles ("Oldowan") were found in the Omo area.

These findings placed the first appearance of stone tools prior to 2 Ma, and therefore c 250 k.a. older than the industries found at Olduvai Bed I, which until then were thought to be the oldest human artifacts anywhere.

Figure 3
The The Shungura Formation in the Lower Omo Valley is currently dated from 3.6 Ma and ca. 1 Ma. 

Within the Omo Group, all early documented archaeological material comes from the Member F deposits of this formation. dating from 2,32 Ma to 2,23 Ma.

While the discovery of artefacts dated to ca. 2,6 Ma in Hadar, and 2,4-2,3 Ma in (Gona, Hadar, Lokalalei and Kanjera) demonstrated that the Omo lithic record is not the oldest-known lithic industry, it still represents an exceptional ensemble for assessing Early Pleistocene hominin behaviors.

The earliest Omo assemblages share a number of features with Gona, Hadar, Lokalalei and Kanjera. With regard to assemblage composition, all these sites show similar percentages of cores and flakes.

Standardized forms are absent and retouched tools are rare. Recurrent reduction of the same exploitation surfaces of cores is well attested, although there is substantial inter-assemblage variation regarding the use of unifacial, bifacial and multifacial methods. Core striking platforms are usually unprepared and rejuvenation products are rare. Once the knapping surfaces lost the necessary convexities, cores were discarded.

Raw material selectivity has been reported in most of the early sites. It is proposed, that the quality, large size and abundance of cobbles at Gona and Hadar has promoted longer sequences of core exploitation, while the smaller size of cobbles at Omo  prevented per-se any sophisticated knapping action.

The Oldowan in the Omo Valley and elsewhere in East Africa was always seen as an adaption of Homo. sp. (Habilis, early Erectus) to changing environments and open Savannah grassland.

Anyhow, the discovery of cut-marked fossils in Dikika that could be older than 3, 39 Ma and discovery of the earliest known stone tools at Lomekwi 3 (LOM3) from West Turkana, Kenya, dated to 3, 3 Ma, raises new questions about the mode and tempo of key adaptations in the hominin lineage.

If we still define Homo as stone tool making creature, it must have existed earlier that currently substantiated by the Paleoanthropological record.

Anyhow, fossils dating to before 2, 8 Ma have not yet been found. Alternatively we could say goodby to the  "Homo the toolmaker" -paradigm  and  attribute the first stone artifacts from LOM3 to an earlier hominin like Australopithecus or even to an extinct large ape.

Lombard et al. have used a cognitive Archeological approach to compare the bipolar technique at Lomekwi with the technological behaviors of recent apes.

They demonstrated " a marked difference in broad-spectrum cognitive requirements between capuchin pounding on the one hand and Lomekwian bipolar knapping on the other.

Whereas the contrast is less pronounced between chimpanzee nut-cracking scenarios and basic passive-hammer knapping at Lomekwi 3, the escalation in cognitive requirement between nut cracking and bipolar knapping is a good indication that early hominin flaking aking techniques are cognitively more taxing than chimpanzee nut-cracking behavior today