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- Title
Rapid strengthening of westerlies accompanied intensification of Northern Hemisphere glaciation.
- Authors
Bridges, Joshua D.; Tarduno, John A.; Cottrell, Rory D.; Herbert, Timothy D.
- Abstract
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 CO2. The amount and composition of North Pacific dust tracked by rock magnetism suggests that the intensification of North Hemisphere Glaciation ca. 2.7 million years ago marked the permanent crossing of a climate threshold.
- Subjects
GLACIATION; WESTERLIES; MINERAL dusts; MARINE sediments; ICE sheets; TROPICAL cyclones; GLOBAL cooling
- Publication
Nature Communications, 2023, Vol 14, Issue 1, p1
- ISSN
2041-1723
- Publication type
Article
- DOI
10.1038/s41467-023-39557-4