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| Titel |
Southern Ocean circulation changes across the last deglaciation: contribution from Marion-Dufresne cruises |
| VerfasserIn |
Elisabeth Michel, Giuseppe Siani, Alain Mazaud, Martine Paterne, Tim DeVries, Samuel Jaccard, Claire Waelbroeck, Xavier Crosta, Gülay Isgüder, Fabien Dewilde, Ricardo De Pol-Holz, Luke Skinner, Catherine Kissel |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250113353
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| Publikation (Nr.) |
 EGU/EGU2015-13550.pdf |
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| Zusammenfassung |
| The last deglaciation is marked by rapid climatic events linked to large reorganizations of the deep ocean circulation. To decipher the role of the Southern Ocean in these deep circulation changes requires reconstructing the evolution of its stratification and its zonal behavior during the last deglaciation from high resolution, well dated records. Furthermore, nowadays the connection between atmosphere and the deep ocean occurs through the Southern Ocean, and it might had a leading role in the evolution of atmospheric CO2 concentrations across the deglaciation. However, establishing a precise chronology for marine sediment records in high latitudes is a difficult task, as it requires the determination of radiocarbon surface water age changes.
It has been possible to retrieve high sedimentation rate cores during Indian and Pacific oceanographic cruises, particularly PACHIDERME and INDIEN SUD expeditions. We pre. We aim at tying these marine records to terrestrial records, using tephra deposited in marine and terrestrial region in the different sector of the Southern Ocean when it is possible. This work is in progress within a French-Swedish project. We will present results at different depth from South West Pacific sector of the Southern Ocean and from the Indian sector. A precise chronology in the Indian sector requires to first establish the tephrochronology of Kerguelen Islands that is under progress.
We compare these new records with previously published records of the Atlantic and Pacific sectors. It indicates that upwelling events drive radiocarbon changes in waters above 2500 m depth and increases in atmospheric CO2. Oceanic circulation changes are not synchroneous at deeper depth between 2500 and 4000 m depth. Southern Ocean temperature and vertical mixing increases occurs synchroneously with temperature increase above the Antarctic and atmospheric CO2 increases within error of marine and Ice chronologies, while the ACC current intensity decrease (or northward migration) occurred later within the Indian Ocean |
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