Surface form of the south-western sector of the last Kara Sea Ice Sheet |
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| Authors: | JAN TVERANGER VALERY ASTAKHOV JAN MANGERUD JOHN INGE SVENDSEN |
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| Institution: | Section for Geology, Saga Petroleum, KjØrboveien, 1300 Sandvika, Norway;Department of Geology, University of Bergen, Allègt 41, 5007 Bergen, Norway;Institute for Remote Sensing Methods for Geology (VNIIKAM), Birzhevoy proyezd 6, 199034 St. Petersburg, Russia;Centre for Studies of Environment and Resources, HØyteknologi-senteret, University of Bergen, 5020 Bergen, Norway |
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| Abstract: | Recent results concerning the extent of the last Weichselian (Valdaian) Kara Sea Ice Sheet in the area around the Polar Urals and the north-eastern Russian Plain allow reconstruction of the surface form of this part of the ice sheet by using a combination of moraine-ridge elevation data and ice-flow indicators. The resulting reconstruction suggests a thin ice sheet with a pronounced lowering of surface gradient at the transition from bedrock substrate around the Urals to a substrate consisting of unconsolidated sediments in the Pechora Basin. Comparison with similar reconstructions from along the southern and north-western parts of the Laurentide Ice Sheet margin, for which a deformable-bed model of glacier dynamics has been proposed, shows strong similarities in surface gradients and ice thicknesses as well in overall sedimentological and morphological characteristics of the associated basal till-deposits. This suggests comparable styles of glacier dynamics for the two ice sheets. If this first approximation of the Kara Sea Ice Sheet surface form is correct, it can be postulated that at least the south-western part of the ice sheet was much more mobile and dynamic than previously expected. |
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