Three-dimensional models in morphometric analysis of cores from the Obishir-5 site (Fergana valley, Kyrgyzstan)

The Obishir-5 site is a key Central Asian site for understanding neolithization and characterizing changes in the lithic production during transition to producing economy. During the fieldwork at the Obishir-5 site, a representative collection of artifacts was obtained and a detailed technical and typological description of the main categories was provided. Knapping techniques, such as pressure and percussion by soft hammer, were tentatively determined for the major part of cores. One of the main identification criteria included the angle between the striking platform and the core front (pressure-close to 90°, percussion technique-close to 75°). Moreover, reduction methods for the striking platform, the shape of the blank negatives, their regularity and orientation were also taken into account. Measurements, using a protractor, of the angle between the striking platform and the core front were problematic because most cores are severely depleted, with the traces of final adjustments and removals. However, the use of high-quality scalable 3D models allowed performing successful measurements and calculating the items ' volumes. As a result, an average angle for the cores with pressure technique signs was 87.7°, and with signs of percussion-78.3°. Cores from the first group are, on average, nearly 4 times smaller and more standardized. The results of the analysis of three-dimensional models confirm our conclusion on the use of two types of knapping technologies made using the traditional morphological analysis. During the work, the efficiency of using three-dimensional modeling for studying the archaeological collection was shown. The employed technique measurement will be adjusted and updated in the course of further investigations. A detailed analysis of 3D models of experimental cores, new finds from the Obishir-5 site, as well as artifacts obtained from collections from other Central Asian sites has been planned.