Waste from manufacturing thin bifacial points of the initial Upper Palaeolithic of the Altai: experimental data

This article describes experimental reconstruction of manufacturing a thin leaf-shaped biface as a form which commonly appears in the industries of the Initial Upper Paleolithic in the Altai. The study was aimed at establishing the structure and other features of debitage from biface production. High-quality Altai raw materials and antler hammer were used for secondary thinning. The results were expected to elucidate the problems of identifying thinning spalls in collections, estimating specific weight of "bifacial” debitage in industries, and studying spatial and temporal aspects of tool production. It has been discovered that the production process of a symmetrical and thin medium-sized bifacial tool could include several stages: primary reduction followed by preparation of the preform, three cycles of secondary thinning, and a cycle of retouching. During reduction, the blank would lose about 85% of its volume, decreasing by an average of 1.5-2 times per cycle. The weight of the original piece would decrease by almost 15 times. In terms of quantity and weight, the major part ofproduction waste emerged from preform preparation and second thinning cycle. A total of 441 identifiable flakes and over a thousand artifacts were obtained. It has been also established that the trimming spalls, regardless of stage and cycle, were distinguished by asymmetrical polygonal or divergent shape, short or shortened proportions, and slightly curved or straight profile. Thinning flakes have shown absent, indefinable, or segmental relatively miniature striking platforms and unidirectional or bidirectional dorsal facets depending on the length of the spall. Generally, bifacial debitage has specific diagnosable appearance, and may be identified in archaeological context. Tentative differentiation by stage is also possible.