HR: 1340h
AN: PP33B-0923    [Abstracts]
TI: Weichselian Glaciation History in the 'dry Valleys' of East-Central Southern Norway
AU: * Dahl, S
EM: Svein.Dahl@geog.uib.no
AF: Department of Geography/ Bjerknes Centre for Climate Research, University of Bergen, Breiviksveien 40, Bergen, - N-5045 Norway
AU: Lie, O
EM: Oyvind.Lie@geo.uib.no
AF: Bjerknes Centre for Climate Research, University of Bergen, Allegaten 55, Bergen, - N-5007 Norway
AU: Linge, H
EM: Henriette.Linge@geo.uib.no
AF: Department of Earth Science/ Bjerknes Centre for Climate Research, University of Bergen, Allegaten 41, Bergen, - N-5007 Norway
AU: Pytte, A B
EM: Anne-Grete.Boe@bjerknes.uib.no
AF: Department of Geography/ Bjerknes Centre for Climate Research, University of Bergen, Breiviksveien 40, Bergen, - N-5045 Norway
AU: Murray, A
EM: andrew.Murray@riso.dk
AF: Nordic Laboratory for Luminescence Dating, Riso National Laboratory, Department of Earth Science, University of Aarhus, Roskilde, Roskilde, - DK 4000 Denmark
AU: Tveranger, J
EM: Jan.Tveranger@cipr.uib.no
AF: Centre for Integrated Petroleum Research, University of Bergen, Allegaten 41, Bergen, - N-5007 Norway
AU: Nesje, A
EM: Atle.Nesje@geo.uib.no
AF: Department of Earth Science/ Bjerknes Centre for Climate Research, University of Bergen, Allegaten 41, Bergen, - N-5007 Norway
AB: East-central southern Norway is situated within the zone of inferred cold-based (low-erosive) ice-sheets during the Late Weichselian maximum in central Scandinavia. The region has high bedrock coverage of Quaternary deposits, while morphological features are mainly glaciofluvial deltas, kame terraces, shorelines, marginal moraines and various indicators of ice-marginal meltwater drainage. In the studied area, former meltwater flow patterns at high altitudes indicate drainage from east, south and west towards the `dry valleys' of Dor†len, Haverdalen, Grimsdalen and upper Folldal north of the Rondane mountains, and then further northwards across the main watershed to Trondelag. At present, the region is among the driest in Scandinavia with most of the precipitation related to south/south-easterly winds. With a suggested ice divide south of Rondane during the build-up of continental ice sheets in central Scandinavia, the `rainshadow' may have been even more pronounced during glaciations. Hence, the area north of Rondane is suggested to be a key area for studying glacier inception and wastage of Weichselian ice sheets in central Scandinavia. Based on detailed field investigations, both stratigraphical settings and landforms have been dated by use of Optically Stimulated Luminescence (OSL) dating. The results indicate that no period during the Weichselian obtained a large enough lowering of the regional glacier equilibrium-line altitude (ELA) to produce glacier ice at the terrain surface in the valleys north of Rondane. All glaciers that entered this area were produced elsewhere. Three main glacier events have been recorded: the largest occurred about 110-90 kyr ago during the early Weichselian, the next largest took place during early parts of the Middle Weichselian about 70-60 kyr ago, and the third largest occurred during the Late Weichselian maximum c. 20 kyr ago. Based on OSL-dated sections, long periods in between the major glacier advances were dominated by ice-dammed lakes in the upper valley of Folldal and its tributaries. Periglacial features like fossil rock glaciers and ice-wedge casts are related to several of the periods with glacier advances and/or periods with ice-dammed lakes.
DE: 9335 Europe
DE: 3344 Paleoclimatology
DE: 1824 Geomorphology (1625)
DE: 1827 Glaciology (1863)
DE: 1035 Geochronology
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting