Lithic raw material exploitation in the Sibiryachikha facies, the Middle Paleolithic of Altai

The Sibiryachikha facies of the Middle Paleolithic differs from other contemporaneous industries of Gorny Altai in both technology and typology. We assess the role of lithic raw material in the origin of Okladnikov and Chagyrskaya industries. The proximity of sources of stone is established, and the main criteria of choice-quality and availability-are confirmed. These criteria could be followed by selecting either common rocks of satisfactory quality or less accessible high-quality material such as Cambrian-Ordovician Zasurye jasperoids. These were used selectively, and the quality of raw material determined secondary reduction techniques. The rise in the proportion of Zasurye jasperoids at the late stage of Sibiryachikha did not result from technological progress. Rather, it might reflect greater availability of high-quality material and more sophisticated extraction practices.