Glacial dynamics of the Fennoscandian ice sheet : a remote-sensing study

• Main Author: Dongelmans, Pieter
• Published: University of Edinburgh 1996
• Subjects: 550
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.649641

In this study, the extensive terrestrial record of glacigenic streamlined landforms in Fennoscandia is used to analyse and reconstruct the internal organisation of the Late Weichselian Scandinavian Ice Sheet and its evolution during the deglaciation. The analyses involved the identification of coherent sets of lineations that can be linked to flow systems within the ice sheet. The presence of superimposed sets of glacial lineations makes it possible to work out relative ages for coherent lineation patterns. In a number of cases, absolute dating is possible because lineation patterns can be connected with dated ice marginal positions. The ice sheet organisation in Scandinavia was dominated by the presence of a number of ice streams. In many areas these zones of fast flow are to a large extent controlled by the presence of valleys and troughs. In the case of Central and South Finland and Russian Karelia, however, a persistent system of ice streams/ice lobes developed that was not topographically controlled. The scale of these ice streams is at least an order of magnitude larger than the scale of the underlying topographic variations, both in the vertical and the horizontal dimensions. The regular distribution of these ice streams, their persistence during the Late Weichselian deglaciation and their independence of local topography and geology implies that they are the result of internal dynamic processes and reflect ice flow organisation within the ice sheet. The landform distribution reflect these lateral variations in ice velocity. Ice stream areas are dominated by streamlined bedforms, while in the inter stream areas, hummocky fluvio-glacial deposition is more important. Due to the limited ice activity in the inter stream areas, landforms pre-dating the deglaciation have been preserved here. During deglaciation diachronous, superimposed, patterns of diverging glacial lineations were formed in the ice stream areas.