Carbon isotope evidence for a northern source of deep water in the glacial western North Atlantic

Understanding glacial ocean circulation is tied to understanding heat transport in the North Atlantic, growth and maintenance of ice sheets, and atmospheric CO2 content. The proxy data are sparse, but, for decades, it has been thought that the North Atlantic did not produce deep water during the Las...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences
Main Authors: Keigwin, Lloyd D., Swift, Stephen A.
Format: Text
Language:English
Published: National Academy of Sciences 2017
Subjects:
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5358345/
http://www.ncbi.nlm.nih.gov/pubmed/28193884
https://doi.org/10.1073/pnas.1614693114
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Summary:Understanding glacial ocean circulation is tied to understanding heat transport in the North Atlantic, growth and maintenance of ice sheets, and atmospheric CO2 content. The proxy data are sparse, but, for decades, it has been thought that the North Atlantic did not produce deep water during the Last Glacial Maximum, unlike today. New C isotope results from a core at 5 km in the western North Atlantic indicate a young, glacial deep water may have been formed in the surface Labrador Sea by freezing and brine rejection. These data call for a revised circulation scheme where southern source water centered at 4.2 km would have been sandwiched between glacial North Atlantic intermediate water and the new dense bottom water.