Evaluation of the Capabilities of a Portable X-ray Fluorescence Analyzer for Differentiation of Lithic Raw Materials of AeolianCorraded Artifacts (Based on the Materials of the Osa-Unga Wide Section of the Bratsk Reservoir)

The results of X-ray fluorescence analysis using a portable spectrometer (pXRF) are presented, carried out on a collection of stone aeolian-corraded artifacts from the Melkhitui 2 and Bilchir 4 sites, which are located in the OsaUnga wide section of the Bratsk Reservoir. The aim of the study was to determine a suitable geochemical indicator for identifying blocks of raw materials and groups of rocks similar in composition that were used in lithic production by the Paleolithic population of the Angara region. As a result of the analysis of the aggregate data, it was established that the raw materials are quite diverse and are represented by three main types of rocks: 1) metamorphic/metasedimentary – quartzite, quartzite-sandstone of varying degrees of metamorphism and structure, as well as crystalline schist; 2) sedimentary – mainly sandstone and a small amount of chert; 3) and igneous, among which one granitoid sample stands out, and the rest are varieties of extrusive rock. Considering the petrographic features of the collection, it can be assumed that the sources of raw materials may be associated with Jurassic deposits, which are widespread in the Upper Angara region. For a general characterization of the chemical composition of artifacts and differential diagnostics of rocks (primarily metasedimentary and sedimentary), an analysis of the pXRF data was carried out based on the ratio of aluminosilicate (AM) and hydrolysate (HM) petrochemical modules. In search of the best options for geochemical discrimination, various indicators were tested using different elements, including Al, Ti, Rb, Sr, Y, Zr, Ba. All of them turned out to be practically useless for identifying groups of samples close in composition, which would be similar in color, structure and texture of the rock. As a result, it was established that the best results are demonstrated by the K/Rb to Al2O3 ratio, which made it possible to identify 12 groups of tools that are close to each other both in terms of indicator values and in terms of the physical characteristics of the rock. It was concluded that in eight cases they could have been made from a single block of raw material, and in the remaining cases from different blocks, which at the same time have a common genesis and, apparently, a single stratigraphic position in the deposits

Fluorescence · Operating system · Optics · Physics · Raw material · Spectrum analyzer · Telecommunications · X-ray fluorescence · Chemistry · Computer Science · Geological Studies and Exploration · Image Processing and 3D Reconstruction · Materials Science · Mining and Gasification Technologies