Experimental modelling of grain grinding using stone percussion-abrasive tools

This study is aimed at experimental reconstruction of economic and domestic activities of the Middle and Upper Paleolithic population who lived in the Altai Mountains. At present, the Paleolithic tools designed for grinding plant materials are insufficiently studied at the sites in this region. Analyses of such artefact categories are either preliminary or lack a fundamental evidence base in the form of high-quality photographs with a magnification of х75 and higher. As part of the experimental study, raw materialfor tools was sought in the valley of the Charysh River, in the immediate vicinity of Chagyrskaya Cave. Pebbles from coarse-grained sandstones and effusives were selected for grinding because tools made of such raw materials are most often found at the Paleolithic sites located in the Altai. They were processed using circular movements of the grater against the slab for 0.5 to 2 hours. After the experiments, the produced reference samples were subjected to functional analysis to look for and record use traces in the working areas of the references. The traces were observed using a magnification of x5 tox200. It was found that used tools could be characterized by levelling, pitting, and smoothing of the surface on the faces, and the presence of large or small sub-parallel marks. The working areas of the grinding slab had traces of smoothing and gouging on their faces with the presence of sub-parallel small linear traces; the change in the general relief of the surface is traceable only at the micro-level as a depression. The results offer the challenge for a detailed study of archaeological artefacts of a similar type found in the Altai Mountains.