The SIS limits and related proglacial events in the Severnaya Dvina basin, northwestern Russia: review and new data

Abstract

Two underlying problems of the Late Quaternary history of the Scandinavian Ice Sheet (SIS) are reviewed in the paper: the position of the southeastern SIS boundary at the Late Glacial Maximum (LGM), which is still widely "migrating" depending on authors' concepts, and the formation of associated proglacial lakes (i.e. their dimensions, drainage and chronology) in the valleys of Severnaya Dvina River basin. The position of maximum ice limit in the northwest of the Russian Plain remains debatable and is the least reliable compared to the other SIS sectors. Most of the recent reconstructions concerning ice-dammed lakes (water overflows, restructuring of river valleys etc.) exploited the geological survey results of mid-20 th century: since then no geological studies have been conducted of the proposed spillways, their filling sediments and age using the modern sedimentological and geochronological techniques. As a result, the majority of the above-mentioned reconstructions have to be considered hypothetical. Here we present new results on two valley sites that allow to suggest that: 1) the SIS did not advance through the lower and middle Vychegda valley at LGM as suggested in some recent publications; 2) the LGM glacier-dammed lake had a very limited extension in the Severnaya Dvina valley and did not exceed to the Vychegda River mouth.

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“…The MIS 2 maximal glacial boundary of the southeastern sector of the Scandinavian Ice Sheet (SIS) along with the interpretation of the MIS 2 sedimentary environments in the Severnaya Dvina River basin are highly debatable and controversial (Zaretskaya et al, 2018;. Scenarios of the LGM glacial advance, ice-dammed lakes formation and reversal runoff into the Caspian basin through the Keltma spillway have been proposed and discussed in (Larsen et al, 2013;Zaretskaya et al, 2018). The LGM glacial limits advancing farther eastwards into the valleys of Severnaya Dvina and Vychegda were proposed in (Lavrov & Potapenko, 2005;Lysa et al, 2011;Fredin et al, 2012;Larsen et al, 2013).…”

Limited extension of the MIS 2 proglacial lake in the Severnaya Dvina valley, south‐eastern margin of the last Scandinavian Ice Sheet

“…An alternative scenario was proposed by another research group (Sidorchuk et al, 1999(Sidorchuk et al, , 2001Zaretskaya et al, 2014Zaretskaya et al, , 2018Zaretskaya et al, , 2020Panin et al, 2020). They questioned the existence of large ice-dammed lakes in the Vychegda basin and presented evidence for fluvial and then aeolian deposition on the Marine Isotope Stage (MIS) 2 terraces (Zaretskaya et al, 2020).…”