Rapid strengthening of westerlies accompanied intensification of Northern Hemisphere glaciation

The trigger, pace, and nature of the intensification of Northern Hemisphere Glaciation (iNHG) are uncertain, but can be probed by study of ODP Site 1208 North Pacific marine sediments. Herein, we present magnetic proxy data that indicate a 4-fold increase of dust between ~ 2.73 and ~ 2.72 Ma, with s...

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Bibliographic Details
Published in:Nature Communications
Main Authors: Bridges, Joshua D., Tarduno, John A., Cottrell, Rory D., Herbert, Timothy D.
Format: Text
Language:English
Published: Nature Publishing Group UK 2023
Subjects:
Article
Pacific
Ice Sheet
North Atlantic
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10318093/
http://www.ncbi.nlm.nih.gov/pubmed/37400450
https://doi.org/10.1038/s41467-023-39557-4
Description
Summary:The trigger, pace, and nature of the intensification of Northern Hemisphere Glaciation (iNHG) are uncertain, but can be probed by study of ODP Site 1208 North Pacific marine sediments. Herein, we present magnetic proxy data that indicate a 4-fold increase of dust between ~ 2.73 and ~ 2.72 Ma, with subsequent increases at the start of glacials thereafter, indicating a strengthening of the mid-latitude westerlies. Moreover, a permanent shift in dust composition after 2.72 Ma is observed, consistent with drier conditions in the source region and/or the incorporation of material which could not have been transported via the weaker Pliocene winds. The sudden increase in our dust proxy data, a coeval rapid rise in dust recorded by proxy dust data in the North Atlantic (Site U1313), and the Site 1208 shift in dust composition, suggest that the iNHG represents a permanent crossing of a climate threshold toward global cooling and ice sheet growth, ultimately driven by lower atmospheric CO(2).

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