Cornelissen, E. .,  Preuss, J.,  Mees, F. & Wotzka, H.-P. 2026. ‘Stone for the Stone Age in the Inner Congo Basin’. Journal of Archaeological Science: Reports 69. URL: https://doi.org/10.1016/j.jasrep.2025.105508.  (PR).

Article in a scientific Journal / Article in a Journal

Reconstructing ancient human occupation of the Equatorial Forest of the Inner Congo Basin (ICB) situated in the Democratic Republic of Congo (DRC) is particularly challenging due to the fragmentary Stone Age archaeological record which is essentially composed of surface finds along the northern shores of Lake Tumba and riverbanks to the east. In order to assess the impact of availability of knappable stone on the nature of the lithic component of material culture in possibly ancient and recent times in the ICB, we provide for the first time a petrographic analysis of silicified sandstone samples from artefacts and non-flaked stone from the Lake Tumba area. They are compared to samples from silicified sandstones of the Série des Grès Polymorphes of which outcrops can be found 200‒250 km to the south and west. The rocks from Lake Tumba clearly belong to these silicified sandstones, however, specific characteristics also point to local provenance which corroborates the few historical records on very rare sources of stone inside the ICB. We analysed lithic artefacts collected in 2017 on the northwestern lakeshore for size and presence and extent of cortex revealing miniaturisation as an adequate technological strategy for surmounting raw material constraints in either scenario of long-distance or local yet unpredictable stone supply. The general small size and the presence of bifacially flaked and transverse arrowheads evokes typological parallels with the Holocene Tshitolian in southwestern Central Africa. Miniaturisation is an efficient strategy for maximising exploitation of scarce sources of stone and might be a timeless asset in areas poor in raw materials for cutting and piercing equipment as is the case in the ICB.