A Eurasian Basin sedimentary record of glacial impact on the central Arctic Ocean during MIS 1-4

Pronounced Quaternary circulation and depositional changes in the Arctic Ocean basins remain poorly under-stood. We investigate sediment core ARC5-ICE4 (ICE4) in the Eurasian (Amundsen) Basin off the Lomonosov Ridge to reconstruct glacial-interglacial variability in sediment sources and circulation. The ICE4 record features variable lithologies including distinct glacigenic deposits with Ice Rafted Debris (IRD). The sediment age is constrained by a combination of the organic carbon 14C with paleomagnetic data and correlation to earlier developed stratigraphies. The derived sedimentation rates constitute several cm/kyr (6.5 cm/kyr average) consistent with estimates from regional geophysical data. The developed age model covers the time interval from ca. 10 to 75 ka including Late and Middle Weichselian/Wisconsinian glaciations. Respective glacigenic sediments were primarily deposited by pulsed iceberg discharge. The Last Glacial Maximum and deglaciation is expressed in sharp IRD peaks including mineral proxies of the Laurentide Ice Sheet with an apparent millennial-scale variability. The older glacigenic sedimentary unit with abundant IRD of predominantly Siberian provenance was deposited during deglaciation of the Middle Weichselian (MIS 4/3) Eurasian Ice Sheet. These sedimentary differences indicate diverging impacts of the two glaciations on the Arctic Ocean, including ice-sheet sizes/ge-ometries and oceanic circulation.

Automated summary

This study investigates sediment cores in the Arctic Ocean to understand the changes in circulation and deposition during glacial and interglacial periods. The results show that the sediment characteristics vary between different glaciation periods, indicating different impacts on the Arctic Ocean including ice-sheet sizes and oceanic circulation.