Numerical modelling provides evidence of a Baltic Ice Stream during the Younger Dryas |
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| Authors: | PER HOLMLUND JAMES FASTOOK |
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| Institution: | Department of Physical Geography, University of Stockholm, S-106 91 Stockholm, Sweden;James Fastook, Department of Computer Science, University of Maine, Orono, Maine 04469, USA |
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| Abstract: | In an effort to analyse the complex Younger Dryas event in central Scandinavia a finite-element method solution of the continuity equation has been used to describe the glaciological processes involved. In order to make the model compatible with the geologic evidence, it is suggested that the ice sheet was drained by a 'Baltic Ice Stream'. The Ice Stream was steered by differences in basal conditions. We also conclude that the climatic event responsible for the Younger Dryas stillstand was probably short (< 500 years), and that different regions of the ice sheet responded in different ways. During a simulated termination it was shown that there was broad agreement about the marginal positions in Sweden and Finland if it was assumed that there was a general sliding zone for elevations below 100 m. with an enhanced sliding zone through the centre of the Baltic and the Gulf of Bothnia. A stillstand near the position of the Younger Dryas moraines is attained with a climatic equilibrium line altitude (ELA) depression of 600 m for a period of 500 years. Agreement of simulated behaviour with observed behaviour is less consistent for the more maritime areas of western Sweden and western Norway. |
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