Investigation of a depression under initial Upper Paleolithic archaeological horizon at the Tolbor 21 site (Northern Mongolia) in 2021-2022

The articles discusses the results of the study of a depression under the archaeological horizon (AH) of the Initial Upper Paleolithic at the Tolbor 21 site in northern Mongolia. Similar items primarily filled by faunistic materials have been described at the Initial Upper Paleolithic sites in the neighbouring regions of Transbaikalia. The complex context of deposits (slope, temperature and humidity variations), however, necessitates the detailed study of distribution of finds and possible postdepositional displacements. The purpose of the article is to characterize the depression investigated at the Tolbor 21 site in 2021-2022 and to consider it in the context of sedimentation and settlement activity at the site. The distribution of finds was investigated by generating AH plans and vertical cross-sections. Fabric analysis was performed to determine postdepositional processes which influenced the distribution of finds. The size of finds was compared between AHs using the Mann-Whitney U-test. As a result, we found that finds in the depression were buried rather quickly and were not affected by solifluction like overlying AH 4. The finds in the depression differ from AH 4 in their statistically significantly smaller sizes, the composition of the finds at the site is characterized by a high proportion of faunistic remains, among which there are red deer antlers unknown from other horizons; the share of the tools is high. The elongated shape of the pit extended along the direction of the sediment slope is the evidence of the natural origin of the pit, which, however, does not rule out its use by the ancient inhabitants of the site.