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Abstract: The configuration of the marine-based NW Fennoscandian ice sheet during the Last Glacial Maximum (LGM) and deglaciation is reconstructed using detailed swath bathymetry and high-resolution seismic data. The investigated area covers about 10,000 km2 of the continental shelf off Troms, northern Norway. Large scale morphology is characterized by cross-shelf troughs, coast-parallel troughs and banks. Based on mega-scale glacial lineations (MSGL), lateral and shear zone moraines and grounding zone systems, the extent and dynamics of the ice sheet during the LGM are deduced. MSGL indicate fast-flowing ice streams in the cross-shelf troughs, while the glacial morphology on the banks indicates more sluggish ice here. The marine-based part of the Fennoscandian ice sheet was sourced from ice domes in the east via fjord and valley systems inshore. Using a balance flux approach, we estimate palaeo-ice stream velocities during the LGM to be approximately 350 m/year. Three deglaciation events have been reconstructed: i) During the Torsken-1 event the ice sheet halted or readvanced to form groundings zone wedges (GZW) and the Torsken moraine, ii) Several still-stands or readvances characterized the ice behaviour on the shallower banks during the Torsken-2 event, iii) During the Flesen event, prominent end moraines in the inner parts of the troughs and banks were deposited. The locations of the end moraines and GZW in the troughs indicate that the retreat of marine-based ice streams in areas of reverse bed slope was episodic, probably mainly due to the variation in widths of the cross-shelf troughs. [Copyright &y& Elsevier]

To better understand the past retreat patterns and chronologies of major marine-terminating outlet glaciers, the Late Weichselian and Holocene glacial history of a NE Greenland fjord system is reconstructed using new and previously published swath bathymetry and high-resolution seismic data, supplemented with multi-proxy analysis of sediment cores. The investigated area extends more than 190 km, including Fosters Bugt, Kejser Franz Josef Fjord, Nordfjord and Moskusoksefjord, the drainage routes for Waltershausen Gletscher, one of the largest outlet glaciers in the NE sector of the Greenland Ice Sheet. A complex of moraine ridges identified in Fosters Bugt show former stillstand positions during this period, and, alongside radiocarbon ages, supports the theory of a maximum ice front position in the outer coastal areas during the Younger Dryas-Preboreal period. The retreat moraines distributed within the Kejser Franz Josef Fjord system provide evidence of a stepwise retreat during the last deglaciation, whereby rapid retreat was interrupted by episodes of stillstands and/or readvances of the grounding line. The fjord system was mostly deglaciated prior to 7.8 ka cal BP, with an estimated average retreat rate ranging between 33 and 96 m a−1 since the Younger Dryas. Following this, only minor ice advances in the inner fjords have been identified. The sediment supply from Waltershausen Gletscher dominated the Kejser Franz Josef Fjord, Nordfjord and outer Moskusoksefjord throughout the Holocene period, whereas in the middle and inner Moskusoksefjord the sediment deposits reflect a more local catchment area. The estimated average retreat rate is in the same order of magnitude as the rates from fjords of northern Fennoscandia, indicating the same overall control for the deglaciation, ice melting from increased Northern Hemisphere summer insolation that peaked in Early Holocene. • Maximum ice front position in the outer coastal areas during the Younger Dryas-Preboreal period. • Rapid retreat was interrupted by episodes of stillstands and/or readvances. • The fjord system was mostly deglaciated prior to 7.8 ka cal BP. • Estimated retreat rate ranged between 33 and 96 m a−1 since the Younger Dryas. [ABSTRACT FROM AUTHOR]

The response of glaciers and ice caps to past climate change provides important insight into how they will react to ongoing and future global warming. In Svalbard, the Holocene glacial history has been studied for many cirque and valley glaciers. However, little is known about how the larger ice caps in Svalbard responded to Late Glacial and Holocene climate changes. Here we use lake sediment cores and geophysical data from Femmilsjøen, one of Svalbard's largest lakes, to reconstruct the glacial history of the Åsgardfonna Ice Cap since the last deglaciation. We find that Femmilsjøen potentially deglaciated prior to 16.1 ± 0.3 cal ka BP and became isolated from the marine environment between 11.7 ± 0.3 to 11.3 ± 0.2 cal ka BP. Glacial meltwater runoff was absent between 10.1 ± 0.4 and 3.2 ± 0.2 cal ka BP, indicating that Åsgardfonna was greatly reduced or disappeared in the Early and Middle Holocene. Deposition of glacial-meltwater sediments re-commenced in Femmilsjøen at c. 3.2 ± 0.2 cal ka BP, indicating glacier re-growth in the Femmilsjøen catchment and the onset of the Neoglacial. The glacier(s) in the Femmilsjøen catchment area reached sizes no smaller than their modern extents already at c. 2.1 ± 0.7 cal ka BP. Our results suggest that larger Svalbard ice caps such as Åsgardfonna are very sensitive to climate changes and probably melted completely during the Holocene Thermal Maximum. Such information can be used as important constraints in future ice-cap simulations. • Geophysical data and lake sediment cores from Femmilsjøen, one of Svalbard's largest and deepest lakes. • Data indicate early deglaciation and constrain the Holocene glacier minimum as well as the onset of the Neoglacial. • Larger Svalbard ice caps such as Åsgardfonna are very sensitive to climate changes. • Link between lacustrine archives of smaller glaciers/cirques and marine fjord archives of the larger ice caps in Svalbard. [ABSTRACT FROM AUTHOR]