Radiocarbon dating was carried out at the Laboratory of Radiocarbon Dating and Electronic Microscopy, Institute of Geography, Russian Academy of Sciences, Moscow, Russia, and the Center for Applied Isotope Studies, University of Georgia, United States (direct measurements with an acceleration mass spectrometer). Radiocarbon ages were calibrated using OxCal 4.3.2 using CALIB 7.1 program with the IntCal13 calibration curve (Stuiver et al., 2019; Reimer et al., 2013).Stable isotope analyses were made at the isotope laboratory of the Geographical Department of Moscow University on a Finnigan Delta-V mass spectrometer with the standard gas-bench option (Prof. Yu. Vasil'chuk and Dr. N.Budantseva). The δ¹⁸О and δ²H values were expressed per mill (‰) as the deviation of the respective isotope ratios of the measured samples from the Vienna standard mean ocean water VSMOW (δ¹⁸О = 0 ‰, δ²H = 0 ‰) and Greenland Ice Sheet Precipitation GISP (δ¹⁸О = –24.76 ‰, δ²H = –189.5 ‰), as well as IAEA laboratory standards (IAEA 12, δ¹⁸О = –12.10 ‰, δ²H = –85.9 ‰; IAEA 13, δ¹⁸О = –33.35 ‰, δ²H = –257.2 ‰) and the domestic Moscow University standard of fresh snow from the Garabashi glacier in the Cuacasus (δ¹⁸О = –15.60 ‰, δ²H = –110.0 ‰). The precision of the measurements was 0.1 ‰ for δ¹⁸О and 0.6 ‰ for δ²H.