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 CO uptake. However, when and how the Antarctic Circumpolar Current reached its modern-like characteristics remains disputed. Here we present neo...

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Detalles Bibliográficos
Autores: 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, Mathie, Paredes, Eduardo, García-Solsona, Ester, López-Quirós, Adrián, Escutia, Carlota
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2024
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/354812
Acceso en línea:http://hdl.handle.net/10261/354812
Access Level:acceso abierto
Palabra clave:Antarctic Circumpolar Current
Antarctic Ice Sheet
Antarctica
Southern Ocean
Cenozoic
Circumpolar current
Global climate
Miocene
Neodymium isotope
Sea ice
Silt
Descripción
Sumario:The Antarctic Circumpolar Current plays a pivotal role in global climate through its strong influence on the global overturning circulation, ocean heat and CO 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.

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