IDENTIFICATION OF MARKER HORIZON IN BOTTOM SEDIMENTS OF THE ONEGA PERIGLACIAL LAKE

Abstract

Degradation of the Scandinavian late Valdai Glaciation in the Onega Lake depression and on adjacent lowlands resulted in the formation of the large Onega periglacial lake (OPL). Its area, depth, and outflow threshold changed time and again during deglaciation. Bottom sediments of the OPL are mainly represented by gray varved clay, more than 7 m thick, deposition of which proceeded from 12.4 to 10.4 ka ago (according to 14C data). Almost black (shungiterich), pinkish gray (carbonate), and pinkish brown (varved) clays are also found.