Labrador Sea freshening at 8.5 ka BP caused by Hudson Bay Ice Saddle collapse

A significant reduction in the Atlantic Meridional Overturning Circulation and rapid northern Hemisphere cooling 8200 years ago have been linked to the final melting of the Laurentide Ice Sheet. Although many studies associated this cold event with the drainage of Lake Agassiz-Ojibway, recent model...

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Bibliographic Details
Published in:Nature Communications
Main Authors: Lochte, Annalena Antonia, Repschläger, Janne, Kienast, Markus, Garbe-Schönberg, Dieter, Andersen, Nils, Hamann, Christian, Schneider, Ralph
Format: Text
Language:English
Published: Nature Publishing Group UK 2019
Subjects:
Article
Greenland
Hudson
Hudson Bay
Ice Sheet
Labrador Sea
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6362222/
http://www.ncbi.nlm.nih.gov/pubmed/30718573
https://doi.org/10.1038/s41467-019-08408-6
Description
Summary:A significant reduction in the Atlantic Meridional Overturning Circulation and rapid northern Hemisphere cooling 8200 years ago have been linked to the final melting of the Laurentide Ice Sheet. Although many studies associated this cold event with the drainage of Lake Agassiz-Ojibway, recent model simulations have shown that the Hudson Bay Ice Saddle collapse would have had much larger effects on the Atlantic Meridional Overturning Circulation than the lake outburst itself. Based on a combination of Mg/Ca and oxygen isotope ratios of benthic foraminifera, this study presents the first direct evidence of a major Labrador shelfwater freshening at 8.5 ka BP, which we associate with the Hudson Bay Ice Saddle collapse. The freshening is preceded by a subsurface warming of the western Labrador Sea, which we link to the strengthening of the West Greenland Current that could concurrently have accelerated the ice saddle collapse in Hudson Bay.

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