The Last Glacial Maximum, Deglaciation and Post-Glacial History of Forlandsundet, an Inter-Ice Stream Glaciated Margin, Western Svalbard

The Late Glacial Maximum and post-glacial history of Forlandsundet, the strait between western Spitsbergen and Prins Karls Forland, was unresolved. Previous terrestrial field studies report contradicting evidence for an ice sheet overriding the entire strait as well as the complete absence of glacier ice within the strait during the Last Glacial Maximum. This multi-proxy investigation of a marine sediment core, high-resolution seafloor morphology and aerial imagery from Forlandsundet reveals glacial till of 14 cal. ka BP minimum age and geomorphological landforms associated with an inter-ice-stream glaciated margin, providing new evidence that Forlandsundet was fully glaciated during the Last Glacial Maximum. This was followed by a slow retreat of glacier ice during the Bølling-Allerød interstadial (14.7 – 12.7 cal. ka BP) and Younger Dryas chronozone (12.7 – 11.7 cal ka BP). The Holocene record is incomplete, with an age hiatus from 11.8 to 7.4 cal ka BP, likely due to a large-scale erosive event. This is followed by a favourable environment for benthic foraminifera in the mid Holocene, and gradual cooling towards the late Holocene. The findings of this study resolve the debate on the extent of the Svalbard-Barents Sea Ice Sheet within Forlandsundet, and provide insights into the deglaciation of a palaeo-inter-ice-stream area valuable to modelling ice-sheet behaviour and decay.