Late Miocene onset of the modern Antarctic Circumpolar Current

The Antarctic Circumpolar Current plays a pivotal role in global climate through its strong influence on the global overturning circulation, ocean heat and CO2 uptake. However, when and how the Antarctic Circumpolar Current reached its modern-like characteristics remains disputed. Here we present ne...

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Bibliographic Details
Published in:Nature Geoscience
Main Authors: Evangelinos, Dimitris, Etourneau, Johan, van de Flierdt, Tina, Crosta, Xavier, Jeandel, Catherine, Flores, José-Abel, Harwood, David M., Valero, Luis, Ducassou, Emmanuelle, Sauermilch, Isabel, Klocker, Andreas, Cacho, Isabel, Pena, Leopoldo D., Kreissig, Katharina, Benoit, Mathieu, Belhadj, Moustafa, Paredes, Eduardo, Garcia-Solsona, Ester, López-Quirós, Adrián, Salabarnada, Ariadna, Escutia, Carlota
Format: Article in Journal/Newspaper
Language:English
Published: 2024
Subjects:
Antarc*
Antarctic
Ice Sheet
Sea ice
Southern Ocean
Online Access:https://hdl.handle.net/11250/3141306
https://doi.org/10.1038/s41561-023-01356-3
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Summary:The Antarctic Circumpolar Current plays a pivotal role in global climate through its strong influence on the global overturning circulation, ocean heat and CO2 uptake. However, when and how the Antarctic Circumpolar Current reached its modern-like characteristics remains disputed. Here we present neodymium isotope and sortable silt records from sediment cores in the Southwest Pacific and South Indian oceans spanning the past 31 million years. Our data indicate that a circumpolar current like that of today did not exist before the late Miocene cooling. These findings suggest that the emergence of a homogeneous and deep-reaching strong Antarctic Circumpolar Current was not linked solely to the opening and deepening of Southern Ocean Gateways triggering continental-scale Antarctic Ice Sheet expansion during the Eocene–Oligocene Transition (∼34 Ma). Instead, we find that besides tectonic pre-conditioning, the expansion of the Antarctic Ice Sheet and sea ice since the middle Miocene Climate Transition (∼14 Ma) played a crucial role. This led to stronger density contrast and intensified Southern Westerly Winds across the Southern Ocean, establishing a vigorous deep-reaching circumpolar flow and an enhanced global overturning circulation, which amplified the late Cenozoic global cooling. publishedVersion

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