Extent, age and dynamics of Marine Isotope Stage 3 glaciations in the southwestern Baltic Basin.

TY - JOUR

T1 - Extent, age and dynamics of Marine Isotope Stage 3 glaciations in the southwestern Baltic Basin.

AU - Houmark-Nielsen, Michael

PY - 2010/4

Y1 - 2010/4

N2 - The southwestern Baltic region is known as a major crossroad for the expansion of Pleistocene glaciers from the Scandinavian Ice Sheet (SIS). At the peak of the Last Glacial Maximum (LGM, 25-20 kyr BP), steady-flowing inter-stream glaciers expanded radially from the major ice divide over central Scandinavia. During the subsequent deglaciation phase (20-15 kyr BP), streaming ice was flowing through the Baltic gateway onto the North European lowland. The lithology and directional ice-flow properties of pre-LGM till formations of Baltic provenance in Denmark (the Ristinge till and Klintholm till) suggest that the ice-sheet dynamics during the Marine Isotope Stage (MIS) 3 glacier expansion were similar to those for the post-LGM advances. Increasing geological evidence indicates that glaciers extended onto the Circum-Baltic lowlands during MIS 3. Reconstructions of flow paths and estimates of the basal ice-sheet coupling in Denmark suggest that southward flow of the SIS through the Baltic was probably the result of ice streaming. Despite methodological uncertainties, available OSL and 14C dates indicate that glaciers advanced at least twice during the mild second half of the Middle Weichselian (c. 75-25 kyr BP), most probably in connection with Dansgaard-Oeschger (D-O) events 14-13 (54-46 kyr BP) and 8-5 (35-30 kyr BP). The chronology and dynamics of glacier expansion in the southwestern Baltic in response to long-term cooling trends, the contemporary presence of a low Arctic biota in large parts of Scandinavia and of possible leads or lags in relation to North Atlantic climate changes during MIS 3 are discussed.

AB - The southwestern Baltic region is known as a major crossroad for the expansion of Pleistocene glaciers from the Scandinavian Ice Sheet (SIS). At the peak of the Last Glacial Maximum (LGM, 25-20 kyr BP), steady-flowing inter-stream glaciers expanded radially from the major ice divide over central Scandinavia. During the subsequent deglaciation phase (20-15 kyr BP), streaming ice was flowing through the Baltic gateway onto the North European lowland. The lithology and directional ice-flow properties of pre-LGM till formations of Baltic provenance in Denmark (the Ristinge till and Klintholm till) suggest that the ice-sheet dynamics during the Marine Isotope Stage (MIS) 3 glacier expansion were similar to those for the post-LGM advances. Increasing geological evidence indicates that glaciers extended onto the Circum-Baltic lowlands during MIS 3. Reconstructions of flow paths and estimates of the basal ice-sheet coupling in Denmark suggest that southward flow of the SIS through the Baltic was probably the result of ice streaming. Despite methodological uncertainties, available OSL and 14C dates indicate that glaciers advanced at least twice during the mild second half of the Middle Weichselian (c. 75-25 kyr BP), most probably in connection with Dansgaard-Oeschger (D-O) events 14-13 (54-46 kyr BP) and 8-5 (35-30 kyr BP). The chronology and dynamics of glacier expansion in the southwestern Baltic in response to long-term cooling trends, the contemporary presence of a low Arctic biota in large parts of Scandinavia and of possible leads or lags in relation to North Atlantic climate changes during MIS 3 are discussed.

U2 - 10.111/j.1502-3885.2009.00136.x.

DO - 10.111/j.1502-3885.2009.00136.x.

M3 - Journal article

SN - 0300-9483

VL - 39

SP - 343

EP - 359

JO - Boreas

JF - Boreas

IS - 2

ER -