Age and extent of the Scandinavian ice sheet in northwest Russia

Abstract

1999 (March): Age and extent of the Scandinavian ice sheet in northwest Russia. Boreas, Vol. 28, pp. 115-132. BornOslo. ISSN 0300-9483. The last glacial maximum (LGM) of the Scandinavian ice sheet in the Arkhangelsk region has been identified morphologically as ridges and hummocks in an otherwise flat topography. Stratigraphically the limit is marked by the presence of till above Mikhulinian (last interglacial) sediments inside the ridges and by the absence of till outside the ridges. During the LGM, ice flowed into the region from the north and northwest forming a lobe in the Dvina-Vaga depression. The continuation northward, northeast of Arkhangelsk, is still somewhat uncertain, but evidence suggests that the outer margin of the Scandinavian ice sheet was situated in the Mezen drainage basin. Luminescence and radiocarbon dates suggest that the maximum position was attained after some 17 ka ago, and that deglaciation started close to 15 ka ago. This age for the maximum position is younger than the maximum position in the western peripheral areas of the Scandinavian ice sheet. This may be accounted for by initial ice build-up in the west followed by a successive migration of the ice divide(s) to the east as ice growth continued. Deglaciation was either by lateral retreat or isolation of dead ice masses causing areal downwasting.

Thickness evolution of the Scandinavian Ice Sheet during the Late Weichselian in Nordfjord, western Norway: evidence from ice-flow modeling

“…Landforms and the sediment record provide good constraints on the maximum lateral extent of the Scandinavian Ice Sheet (e.g. Andersen 1981;Svendsen et al 1999;Larsen et al 1999;Sejrup et al 2000), but its vertical extent and surface profile are more difficult to establish. For example, botanists postulated the existence of ice-free regions in western and northern Norway at the LGM, allowing the survival of endemic plant and animal species (for review, see Nesje et al 1988).…”

Maximum extent of the Eurasian ice sheets in the Barents and Kara Sea region during the Weichselian

“…Recent investigations in the Arkhangelsk region indicate that the Scandinavian Ice Sheet did not inundate the Dvina River basin at this time (Larsen et al 1999). As an implication of the ice sheet reconstruction described below, we assume that the Scandinavian Ice Sheet coalesced with the Barents Ice Sheet, but we have no observations yet to substantiate this assumption and this needs to be tested in the field.…”

“…In the Arkhangelsk region, luminescence dates suggest that the maximum position was attained after 17 000 calendar yrs ago, and that deglaciation started about 16 000 calendar yrs ago (Larsen et al 1999). The region east of Lake Onega was deglaciated between 14 400 and 12 900 calendar yrs ago (Saarnisto et al 1998).…”

“…On the proximal side of the youngest morainic ridges in the Arkhangelsk region (Larsen et al 1999) and in the Pechora Basin (Tveranger et al 1998; Eemian marine sediments are covered by till, whereas on the distal side of the moraines these sediments shows no sign of being overridden by glacial ice. Inside the proposed ice-sheet limit on the Siberian Lowland there Fig.…”

“…In addition to satellite and aerial photographic interpretation, the mapping was carried out through land-based geological field investigations in several sectors of the Russian Arctic from the White Sea region to the Taimyr Peninsula ( Fig. 1) Hahne & Melles 1998;Larsen et al 1999;Möller et al 1999;Tveranger et al 1999). Exposed sections along rivers, lakes and coasts and sediment cores from lake basins have been investigated and dated.…”