Stone-flaking technology at Leang Bulu Bettue, South Sulawesi, Indonesia

Approximately 50000 stone artefacts have been recovered from the prehistoric site of Leang Bulu Bettue (LBB), on the Wallacean island of Sulawesi, in Indonesia. This large assemblage offers the opportunity to produce a large-scale, comprehensive model of the early lithic technologies of South Sulawesi. Through the analysis of half of this assemblage, this study identifies a technological shift between the artefacts produced ca.50-40 thousand years ago (ka) - the "Lower Industry" - and the "Upper Industry" artefacts produced ca.40-16 ka. The majority of the assemblage belongs to the Upper Industry, and these artefacts are associated with portable art, ornamentation, and the Homo sapiens remains reported in previous works. These Upper Industry artefacts are largely made on chert that was brought to the site, sometimes in the form of large flake blanks, which was further reduced within the cave and used for ochre and plant processing. Artefact reduction was strategic during this period, and the bipolar method was frequently used for controlled reduction of flakes of various sizes. This represents a shift from the technology seen on the small number of Lower Industry artefacts, recovered from the deeper deposits. The oldest lithic artefacts yet reported from the site were made on immediately available limestone pieces, which were reduced through least-effort and non-intensive flake removal dictated by the available platforms. This study is compared to an analysis of Pleistocene artefacts at the nearby site of Leang Burung 2, where a similar technological shift has been observed.