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Climate and ocean forcing of ice-sheet dynamics along the Svalbard-Barents Sea ice sheet during the deglaciation ∼20,000–10,000 years BP

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  • Tine L. Rasmussen, UiT The Arctic University of Norway
    • ,
  • Erik Thomsen

The last deglaciation, 20,000–10,000 years ago, was a period of global warming and rapidly shrinking ice sheets. It was also climatically unstable and retreats were interrupted by re-advances. Retreat rates and timing relative to climatic changes have therefore been difficult to establish. We here study a suite of 12 marine sediment cores from Storfjorden and Storfjorden Trough, Svalbard. The purpose is to reconstruct retreat patterns and retreat rates of a high northern latitude marine-based ice stream from the Svalbard-Barents Sea Ice Sheet in relation to paleoceanographic and paleoclimatic changes. The study is based on abundance and composition of planktic and benthic foraminiferal assemblages, ice rafted debris (IRD), lithology, and 70 AMS-14C dates. For core 460, we also calculate sea surface and bottom water temperatures and bottom water salinity. The results show that retreat rates of the ice shelf and ice streams of Storfjorden Trough/Storfjorden (‘Storfjorden Ice Stream’) closely followed the deglacial atmospheric and ocean temperature changes. During the start of the Bølling interstadial retreat rates in Storfjorden Trough probably exceeded 2.5 km/year and more than 10,000 km2 of ice disappeared almost instantaneously. A similarly rapid retreat occurred at the start of the Holocene interglacial, when 4500 km2 of ice broke up. Maximum rates during the deglaciation match the fastest modern rates from Antarctica and Greenland. Correlation of data show that the ice streams in several fjords from northern Norway retreated simultaneously with the Storfjorden Ice Stream, indicating that temperature was the most important forcing factor of the Svalbard-Barents Sea Ice Sheet during the deglaciation.

OriginalsprogEngelsk
Artikelnummer100019
TidsskriftQuaternary Science Advances
Vol/bind3
DOI
StatusUdgivet - apr. 2021

Bibliografisk note

Funding Information:
We thank the captains and crews, shipboard scientific parties, students, and engineer Steinar Iversen for help with core retrievals during cruises with RV Jan Mayen/Helmer Hanssen (UiT the Arctic University of Norway) in 2002?2016 and RV l'Atalante (IFREMER) in 2016. Anders Solheim, Norwegian Geotechnical Institute, NGI, Oslo, Norway is warmly thanked for the figure (Fig. 1B and C) showing the seismic and acoustic data from UNIS AG202/AG216 cruise with RV Jan Mayen in 2002, when core 460 was taken. Jesper Olsen, Aarhus University supervised the datings of cores 564 and 567. This research was funded by UNIS 2002?2004 (University Centre in Svalbard), and TFS (Troms? Forskningsstiftelse), UiT the Arctic University of Norway to the ?Paleo-CIRCUS? project 2010?2014. The project received further funding from 2013 from the Research Council of Norway through its Centres of Excellence funding scheme, project number 223259.

Funding Information:
Here we study the deglaciation history of the Storfjorden Trough/Storfjorden from the northwestern part of the Svalbard-Barents Sea Ice Sheet from the end of the Last Glacial Maximum to the early Holocene (20,000 to ∼10,000 years ago). The investigation is based on a suite of marine cores from close to the shelf edge to the innermost part of the fjord. The chronostratigraphy of the study is supported by 70 AMS- 14 C dates. The climatic and oceanographic reconstructions include sea surface and bottom water temperatures and bottom water salinity calculated from distributional data of planktic and benthic foraminiferal faunas. The dataset also comprises several lithological parameters including the distribution of laminated deposits and the occurrence of ice rafted debris (IRD).

Publisher Copyright:
© 2020 The Authors

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