Reconstruction of the bifacial Technological sequence in Chagyrskaya Cave assemblage

There are three main cultural traditions in Altai’s Late Middle Paleolithic, dating back to MIS4: Denisovan, Kara-Bom, and Sibiriachikha. The Denisovan and Kara-Bom types are technologically and typologically similar and characterized by Levallois and flat parallel flaking, Levallois tools, notched and denticulate tools, as well as simple scrapers. The Sibiriachikha type significantly differs from them due to radial and predominantly orthogonal flaking accompanied by specific tool kit. In the Sibiriachikha assemblages, predominant are convergent tools such as déjeté scrapers and retouched points, typical for the European Micoquian assemblages, associated with Neanderthal human remains. The Sibiriachikha assemblages are characterized by the presence of tool-marker – plano-convex bifaces. The article presents research focused on the reconstruction of bifacial technology and conducted by means of scarpattern analysis, experiments, and mathematical statistics. The research results allowed reconstructing and verifying the main technological stages in bifacial production, distinguishing two main technological sequences of bifacial production via plano-convex and plano-convex alternate techniques. In order to treat complete pebbles, the ‘long’ sequence was used, characterized by a significant amount of technical spalls and waste products such as cortical and partly cortical, fasonnage spalls, and bifacial thinning spalls. In order to produce bifaces from flakes and thin plaquettes, the ‘short’ sequence was used, characterized by fewer technical spalls and waste products. The experiments allowed verifying the obtained results and distinguishing concrete tools used in bifacial production. The combination of statistical analysis and scar-pattern analysis indicated isolated occasions of change in archaeological bifaces.