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| Titel |
Links between CO2, glaciation and water flow: reconciling the Cenozoic history of the Antarctic Circumpolar Current |
| VerfasserIn |
J.-B. Ladant, Y. Donnadieu, C. Dumas |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 10, no. 6 ; Nr. 10, no. 6 (2014-11-14), S.1957-1966 |
| Datensatznummer |
250117074
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| Publikation (Nr.) |
 copernicus.org/cp-10-1957-2014.pdf |
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| Zusammenfassung |
| The timing of the onset of the Antarctic Circumpolar Current (ACC) is a
crucial event of the Cenozoic because of its cooling and isolating effect
over Antarctica. It is intimately related to the glaciations occurring
throughout the Cenozoic from the Eocene–Oligocene (EO) transition (≈
34 Ma) to the middle Miocene glaciations (≈ 13.9 Ma). However, the
exact timing of the onset remains debated, with evidence for a late Eocene
setup contradicting other data pointing to an occurrence closer to the
Oligocene–Miocene (OM) boundary. In this study, we show the potential impact
of the Antarctic ice sheet on the initiation of a strong proto-ACC at the EO
boundary. Our results reveal that the regional cooling effect of the ice
sheet increases sea ice formation, which disrupts the meridional density
gradient in the Southern Ocean and leads to the onset of a circumpolar
current and its progressive strengthening. We also suggest that subsequent
variations in atmospheric CO2, ice sheet volumes and tectonic
reorganizations may have affected the ACC intensity after the
Eocene–Oligocene transition. This allows us to build a hypothesis for the
Cenozoic evolution of the Antarctic Circumpolar Current that may provide an
explanation for the second initiation of the ACC at the Oligocene–Miocene
boundary while reconciling evidence supporting both early Oligocene and early
Miocene onset of the ACC. |
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