Analysis of the Conditions of Late Quaternary Sedimentation in the Tunka Rift Valley for Solving the Problems of Geoarchaeological Research

Purpose . The paper presents the results of comprehensive studies of sediment sections of the reference geoarchaeological sites of the Tunka rift valley, with the aim of reconstructing the conditions and features of local sedimentation during the Late Quaternary period and assessing the influence of these conditions on the strategy of development of the region by ancient humans. Results . The article deals with classifications by granulometric composition and magnetic properties of sediments. According to the classification of N. N. Verzilin, 6 granulometric types were identified: two types of sand, two types of silty sand, two types of siltstone. The sediments were divided into 2 groups by the degree of variability of their magnetic properties. Conclusion . It has been established that the main agents responsible for the transportation of Pleistocene-Holocene sediments within the Tunka rift valley are catastrophic flows (floods, mudflows, inundations), mobilizing a significant volume of detrital material. Following the receding of water, the material deposited by the floods was subjected to aeolian processing in highly dynamic subaerial conditions, resulting in the formation of a continuous cover loess-like complex. This, in turn, caused the total activation of slope-wash processes. Additional material was brought in the form of air suspensions and was also deposited in a complex with local products of the blowing and scattering and reweaving of catastrophic floods sediments.