Geometry and vertical extent of the late Weichselian ice sheet in northwestern Oppland County, Norway
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- Artikler 
The position of the ice margin during the last deglaciation is well known in Scandinavia, in particular during the Younger Dryas (YD) chronozone from when large ice marginal deposits easily can be traced at or close to the Norwegian coast. However, inland of the YD marginal deposits, the vertical extent and geometry of the Scandinavian ice sheet is still debated. In this study we have used detailed Quaternary geological mapping to reconstruct the ice sheet surface and slope in core areas around the valleys of Gudbrandsdalen, Romsdalen, Eikesdalen\/Litledalen and around lake Aursjøen. In these areas we typically and morphologically distinct lateral moraines at 1300-1500 m a.s.l., which slope down towards the coast and seem to correlate with two known YD stages. By using slope and spatial pattern of the lateral moraines we infer a maximum elevation of the YD ice sheet in central areas around Dombås to be at around 2000 m a.s.l., and mostly lower at 1800 m.a.sl. during significant portions of the YD chronozone. Most inland areas in Norway were thus ice covered during YD, except for high peaks in for example Dovre, Rondane and Jotunheimen, which acted as accumulation area nunataks. Our data also show that the first order ice divide during this stage was situated over Jotunheimen from where significant ice streams emanated and were flowing down into the major valleys and out towards the coast. We stress that this study is preliminary, lacking absolute dates of the lateral moraine zones, but the spatial pattern is very consistent and correlates well with known glacial stages. A dating campaign is underway to elucidate the precise timing of these glacial events, but the picture emerging from this work shows the importance of careful Quaternary geological mapping to understand past ice-sheet configurations.