Intentional fragmentation as a specific initial Upper Paleolithic technology at the Kara-Bom site (Mountain Altai, Russia)

Purpose. Recent investigations have highlighted an Asian variant of the so-called Initial Upper Paleolithic (IUP) broadly comparable in age and material culture to techno-complexes further to the west, but also showing distinct derived features. Several principal common technological features characterize the IUP in East Asia. The main targeted products of flaking were medium or large blades, the latter sometimes of very significant size, and the number of bladelets is also large. Primary flaking is characterized by alternate bidirectional reduction of cores in which spalls, alternately detached from opposing platforms along the long axis of the core, determined the shape of targeted blank: pointed blades. Reduced cores were prismatic, sub-prismatic and flat. Burin-core reduction for bladelet and small blade production was the specific knapping technology employed in the IUP of southern Siberia and Central Asia. Here, we describe and provide corroborating evidence for another distinct technological method employed in the Initial Upper Paleolithic - intentional fragmentation (IF). The most effective means of understanding knapping technology are refitting studies of archaeological collections. This article examines several examples of refitted fragmented cores and blades, as well as debitage as the by-product of blank breakage. Results. Our refitting study includes assemblages from all excavation units and partially divided, relatively homogenous raw material types, representing a diachronic assemblage of Middle and Upper Paleolithic materials, even in very disturbed excavation areas. The present study illustrates the best examples of directional reduction associated with core preparation and tool blank production because of the lack of statistical information for some Upper Paleolithic assemblages from this site. We reconstructed the process of intentional fragmentation for burin-cores and a few large and medium blades. Often, blank breakage produced butterfly-like debitage. Pieces of fragmented blades could have been used as tools. Typical attributes of IF consistently appearing on two transverse edges of blanks and present in the assemblage of artifacts prove the anthropogenic character of these flaking traces. Conclusions. It is probable that intentional fragmentation was used in the Initial Upper Paleolithic assemblage at Kara-Bom because of the influences of mobility and transportation of stone raw material by local settlers. They transported a significant proportion of raw material from primary chert outcrops situated 4-5 km from the Kara-Bom site