HWK EE

HWK EE (Henrietta Wilfrida Korongo East East) is located in the southeast part of the Junction Area at Olduvai Gorge. The site was originally excavated in the early 1970’s by Mary Leakey, and then by the Olduvai Gorge Archaeology Project between 2009 and 2015. It is a late Oldowan site dated to around 1.7 million years ago. HWK EE may represent one of the last Homo habilis sites at Olduvai Gorge, and it is an important site for our understanding of the behavioural and cultural mechanisms that led to the emergence of the Acheulean and Homo erectus in the region.

3D model of the HWK EE locality.

HWK EE is positioned across the boundary between Lower and Middle Bed II, a crucial interval for studying the emergence of the Acheulean at Olduvai Gorge. Our excavations at HWK EE have produced one of the largest collections of fossils and artefacts from any Oldowan site, distributed across several archaeological units and a large excavation surface in four separate trenches that can be stratigraphically correlated.

Aerial view of HWK EE trenches.

Digital elevation model of the HWK EE outcrop.

Close up of the HWK EE trenches from the air.

Results show a great density of fossils and stone tools vertically through two stratigraphic intervals and laterally across an area of around 300 m², and highlight the confluence of biotic and abiotic agents in the formation of the assemblage. The large size and diversity of the assemblage, as well as its good preservation, qualify HWK EE as a reference site for the study of the late Oldowan at Olduvai Gorge and elsewhere in Africa.

Density estimates (a) and Probability surfaces for material location in HWK EE (b), based on artefact density and modern terrain features.

Vertical distribution of fossils and lithics in the HWK EE archaeological units.

The larger mammal fossil assemblage excavated from HWK EE shows evidence of multiple occupations over a long period of time, suggesting the site offered affordances attractive to hominins. There was a water source indicated by the presence of fish, crocodiles and hippos, and there was tree cover in an otherwise open habitat.

Reconstruction of hominin and mammal interactions in HWK EE, based on the archaeological evidence found at the site. Illustration by Benoit Clarys

Proboscidean foot bone from HWK EE with cut marks produced by stone tools, evidencing hominin manipulation of elephant carcasses 1.7 million years ago.

Feeding traces on bone surfaces suggest hominins at the site obtained substantial amounts of flesh and marrow, and exploited a wide range of taxa, including megafauna. However, a strong carnivore signal indicates hominins scavenged much of their animal resources. The diversity of fauna that preserve evidence of butchery suggests the HWK EE hominins were opportunistic in their acquisition of carcass foods.

Fossils and lithics from the HWK EE main trench.

The stone tool assemblage from HWK EE is substantially large, with over 18,000 pieces. Our results indicate that reduction sequences were generally short, flaking productivity was low, and knapping methods were largely simple and expedient, lacking the technical skills observed in other Oldowan assemblages. Nonetheless, knapping expediency and low productivity were accompanied by raw material selectivity and consistent presence of retouched artefacts.

HWK EE lava core.

Quartzite stone tools from HWK EE.

Coexistence of these stone tools features in the same assemblage leads us to question the monolithic structure of the Oldowan techno-complex, and highlights the kaleidoscopic nature of technological strategies at Olduvai immediately before the earliest Acheulean handaxes appear in the sequence.

Lava core from HWK EE.

Retouched flake from HWK EE.

See also the Olduvai sites: MNK Skull Site and EF-HR.