The paper discusses the dating and environmental conditions of the Mesolithic horizons at the Vylys Tom 2 multilayer archaeological site on a 10 m high river terrace in the lower reaches of the Izhma River. It is shown that both cultural layers were formed on the low, elevated, regularly inundated floodplain with no more than a few years in between at about 9.6 ka. The living sites were of a seasonal type and operated only during the warm season. In winter and till the end of the spring snowmelt flood, people migrated to a higher geomorphological level on the 12 to 13 m high terrace, which by that time was no longer flooded. The Mesolithic sites of Vylys Tom 3 and Och’yu Katische, found on this terrace, are dated at 8.8–9.2 ka. After the formation of cultural layers at the Vylys Tom 2 site, there was an incision by the river of 3 ± 1 m. The incision stopped no later than before the onset of the Early Iron Age (about 2.5 ka). The driving force of the river incision was most probably the adjustment of the river slope to the decay of the glacial forebulge related to the MIS 2 glaciation in northeastern Europe.
Panin et al. (2025) studied this question.