Petrography of paleolithic locations in the Northern Aral Sea region (Kazakhstan)

The predominance of arid conditions during the Pleistocene in the territory of Western Kazakhstan caused extremely poor sedimentation, as a result of which the vast majority of Paleolithic sites in this region do not have a stratified cultural layer, and their artifacts of different ages have the same surface occurrence. For the same reason, i.e. the aridity of the region, Paleolithic sites are usually located here either near water sources of various types, some of which do not function presently, or near the outcrops of stone raw materials for the artifact manufacturing. The combination of the first and second factors contributed to the fact that representatives of the oldest populations repeatedly inhabited the same place for a long time. To prove the chronological division of lithic materials in mixed complexes of surface occurrence, in the absence of accompanying bone remains and overlying deposits, we use the degree of preservation of surface artifacts (deflation), which depends on the duration of weathering factors. This caused the study of lithic artifacts of surface occurrence. For this purpose, a petrographic analysis of the items from the Paleolithic locations in the Northern Aral Sea, Aral A-D and Aral-1-2, 4-6, 8, was carried out. The studied raw material is represented by two varieties of quartzite-like quartz sandstones and siltstones, petrophysical differences between which are determined by the rock grain, mineral shape, and structure of cement. Both varieties are high-quality stone raw materials, and the preference of one of them was determined by the predominant distribution at a particular location. The analysis was aimed at answering the question of whether it is legitimate to use the degree of preservation of the item surface as the main periodization criterion. It was established that even within the same artifact, the degree of surface deflation is often different, and therefore cannot be used for their age stratification.