Causes and consequences of Arctic freshwater routing into the Nordic Seas during late Marine Isotope Stage 5

• Published in: Journal of Quaternary Science
• Main Authors: Telesiński, Maciej M., Bauch, Henning A., Spielhagen, Robert F.
• Other Authors: The German Federal Ministry for Education and Science (BMBF), The German-Russian collaborative project ‘Transdrift’
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2018
• Subjects: Paleontology; Earth and Planetary Sciences (miscellaneous); Arts and Humanities (miscellaneous); albedo; Arctic; Arctic Ocean; Foraminifera*; Greenland; Ice Sheet; Kara Sea; Nordic Seas; Sea ice; Siberia
• Online Access: http://dx.doi.org/10.1002/jqs.3060; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjqs.3060; https://onlinelibrary.wiley.com/doi/pdf/10.1002/jqs.3060

ABSTRACT Sediment core PS1904 reveals continuous records of planktic and benthic foraminiferal stable isotopes (δ 18 O/δ 13 C) from the north‐eastern Greenland continental margin. The data show good comparability with other records from the Nordic Seas, allowing the stratigraphic range of PS1904 to be dated to Marine Isotope Stage (MIS) 6. Focusing on MIS 5 reveals light δ 18 O values during MIS 5a compared to the last interglacial peak (MIS 5e) which indicates that surface and bottom water layers were strongly affected by freshwater during the former event. We present two possible scenarios explaining the origin and routing of the freshwater: (i) drainage of a Eurasian proglacial lake coupled with the collapse of the Kara Sea Ice Sheet at the MIS 5b/a boundary, and (ii) destabilization and melting of the nearby Greenland Ice Sheet. Although both scenarios could have acted simultaneously, sediment records from the Eurasian sector of the Arctic Ocean hint at the proglacial lake system in north‐western Siberia as the largest freshwater source. Regardless of the actual source, the freshwater lowered the surface ocean salinity causing water column stratification and sea ice expansion. Increased sea‐ice abundance led to a higher albedo and probably contributed to the cooling and global ice sheet growth that occurred subsequently during MIS 4.