Evolution of a proglacial lake in the Izborsko‐Malskaya Valley, Russia, in the Late Glacial

A proglacial lake system formed during the Late Valdai (Weichselian) Ice Sheet recession on the East European Plain. Poor knowledge about chronology, levels and the drainage pathways of ice‐dammed lakes does not allow us to fully evaluate their palaeogeographic significance. This study focuses on the Izborsko‐Malskaya Valley where fingerprints of a glaciolacustrine environment were found. Based on litho‐, biostratigraphic and geochronological data, it is estimated that the proglacial lake in the Izborsko‐Malskaya Valley existed from ~14.3 ka cal. BP (the Vashinogorskaya Valley from ~14.9 ka (optically stimulated luminescence)) to 13.2 ka cal. BP. The maximum level was ~72 m a.s.l. (above sea level) and the minimum was ~53 m a.s.l. Sedimentation proceeded mostly in deepwater conditions. The ice‐dammed lake in the Izborsko‐Malskaya and nearest valleys could have been part of a huge lake on the Pskov lowland which formed after ~15.7 ka cal. BP. The lake level dropped rapidly when the proglacial Lake Pskovsko‐Chudskoe (Peipsi) connected with the Baltic Ice Lake. A lacustrine regime was preserved only in the southern portion of the Izborsko‐Malskaya Valley after drainage and still exists in the modern lakes. The presented approaches to the ice‐dammed lake reconstruction could be useful for the verification of other lakes which existed on the East European Plain.