Pretreatment for counting material was carried out in the Laboratory of Radiocarbon Dating and Electron Microscopy of the Institute of Geography of the Russian Academy of Sciences, and AMS radiocarbon dating was conducted in the Center for Applied Isotope Studies at the University of Georgia, United States (lab ID is IGANAMS). AMS measurements were performed using a National Electrostatics Corporation (NEC) model 1.5SDH-1 Pelletron accelerator capable of accelerating the +1 charged ions to about 1 MeV.bThe resulting 14C ages were calibrated using the IntCal20 calibration curve (Reimer et al. (2020), doi:10.1017/RDC.2020.41) and the Oxcal version 4.4.4 program (Bronk Ramsey, 2021; https://c14.arch.ox.ac.uk/oxcal.html). Ages were calibrated to calendar years before present (where present is 1950 A.D.) using the IntCal20 calibration curve; age ranges at the 95.4% probability level. Calendar ages are the median age with one sigma uncertainty. Sample processing completed at the Institute of Geography of RAS, analyses completed at the University of Georgia radiocarbon facility.