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Monica Winsborrow, University of Tromsų (Norway)
Karin Andreassen, University of Tromsų (Norway)
Geoffrey D. Corner, University of Tromsų (Norway)
Jan Sverre Laberg, University of Tromsų (Norway)
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The deglaciation of the southern Barents Sea area is reconstructed based on marine and terrestrial datasets. Swath bathymetry, 2D and 3D seismic data, and remote sensing data have been used to map the megascale glacial geomorphology of the southern Barents Sea seafloor, northern Fennoscandia and the Kola Peninsula. This has given new insights into the dynamics and behaviour of the Barents Sea Ice Sheet during the last deglaciation. This area is of particular interest given its location at the confluence of ice flow from the former Fennoscandian, Barents Sea, Svalbard and Kara Sea Ice Sheets, and due to the value of this palaeo-ice sheet as an analogue for the modern West Antarctic Ice Sheet.
The glacial geomorphology indicates clear spatial and temporal variations in ice dynamics, with evidence for both active ice streaming and frozen-bed conditions during deglaciation. An ice stream operated in the major shelf trough of Bjørnøyrenna throughout deglaciation, depositing a large grounding zone wedge ∼100 km upstream of the shelf break. Fast flowing ice also operated in the shelf troughs of Ingøydjupet and Djuprenna. The latter deposited an anomalously large ice marginal deposit (Nordkappbanken). These features indicate significant ice input from the eastern mainland at a late deglacial phase. Frozen bed conditions and glaciotectonic features are identified in the shallow bank area of Tromsøflaket.
Streamlined bedforms and bedrock characterise the seafloor of the fjords of northern Fennoscandia, which acted as tributaries to the ice streams operating on the shelf. Grounding zone wedges and moraines in several fjords mark halts in the southerly retreat of ice towards the mainland. Retreat was not synchronous in all locations, as indicated by differences in the position of ice marginal deposits in adjacent fjords. Onshore zones of streamlined bedforms indicate the flow of warm-based ice towards Altafjord and Tanafjord/ Varangerfjord. These areas would have been the source regions for the offshore ice streams, but they also include landforms relating to the later stages of deglaciation as ice retreated onshore. Ice flow on Kola Peninsula indicates a southerly component flowing into the White Sea, and also a significant northerly component which continues in a westerly direction offshore, feeding ice into the southwest Barents Sea.
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