Ice-sheet dynamics through the Quaternary on the mid-Norwegian continental margin inferred from 3D seismic data |
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| Institution: | 1. Scott Polar Research Institute, University of Cambridge, Cambridge CB2 1ER, UK;2. Geological Survey of Norway, Trondheim N-7491, Norway;3. Department of Petroleum Engineering and Applied Geophysics, Norwegian University of Science and Technology, Trondheim N-7031, Norway |
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| Abstract: | Reconstructing the evolution of ice sheets is critical to our understanding of the global environmental system, but most detailed palaeo-glaciological reconstructions have hitherto focused on the very recent history of ice sheets. Here, we present a three-dimensional (3D) reconstruction of the changing nature of ice-sheet derived sedimentary architecture through the Quaternary Ice Age of almost 3 Ma. An extensive geophysical record documents a marine-terminating, calving Fennoscandian Ice Sheet (FIS) margin present periodically on the mid-Norwegian shelf since the beginning of the Quaternary. Spatial and temporal variability of the FIS is illustrated by the gradual development of fast-flowing ice streams and associated intensification of focused glacial erosion and sedimentation since that time. Buried subglacial landforms reveal a complex and dynamic ice sheet, with converging palaeo-ice streams and several flow-switching events that may reflect major changes in topography and basal thermal regime. Lack of major subglacial meltwater channels suggests a largely distributed drainage system beneath the marine-terminating part of the FIS. This palaeo-environmental examination of the FIS provides a useful framework for ice-sheet modelling and shows that fragmentary preservation of buried surfaces and variability of ice-sheet dynamics should be taken into account when reconstructing glacial history from spatially limited datasets. |
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| Keywords: | Ice stream Fennoscandian Ice Sheet Seismic stratigraphy Marine geology Palaeo-glaciology Glacial geomorphology |
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