A warm and poorly ventilated deep Arctic Mediterranean during the last glacial period

Changes in the formation of dense water in the Arctic Ocean and Nordic Seas [the “Arctic Mediterranean” (AM)] probably contributed to the altered climate of the last glacial period. We examined past changes in AM circulation by reconstructing radiocarbon ventilation ages of the deep Nordic Seas over...

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Bibliographic Details
Published in:Science
Main Authors: Thornalley, D. J. R., Bauch, H. A., Gebbie, G., Guo, W., Ziegler, M., Bernasconi, S. M., Barker, S., Skinner, L. C., Yu, J.
Format: Article in Journal/Newspaper
Language:English
Published: American Association for the Advancement of Science 2015
Subjects:
QE Geology
Arctic
Arctic Ocean
Ice Sheet
Iceberg*
Nordic Seas
North Atlantic
Sea ice
Online Access:https://orca.cardiff.ac.uk/id/eprint/76298/
https://doi.org/10.1126/science.aaa9554
https://orca.cardiff.ac.uk/id/eprint/76298/1/Thornalley%20Nordic%20combined.pdf
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Summary:Changes in the formation of dense water in the Arctic Ocean and Nordic Seas [the “Arctic Mediterranean” (AM)] probably contributed to the altered climate of the last glacial period. We examined past changes in AM circulation by reconstructing radiocarbon ventilation ages of the deep Nordic Seas over the past 30,000 years. Our results show that the glacial deep AM was extremely poorly ventilated (ventilation ages of up to 10,000 years). Subsequent episodic overflow of aged water into the mid-depth North Atlantic occurred during deglaciation. Proxy data also suggest that the deep glacial AM was ~2° to 3°C warmer than modern temperatures; deglacial mixing of the deep AM with the upper ocean thus potentially contributed to the melting of sea ice, icebergs, and terminal ice-sheet margins.

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