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Article Dans Une Revue Geochemistry, Geophysics, Geosystems Année : 2010

Variations of the Antarctic Circumpolar Current intensity during the past 500 ka

Résumé

[1] We examine the past variations of the Antarctic Circumpolar Current (ACC) by using variations in size and abundance of the magnetic grains deposited by this current at a site east the Kerguelen-Crozet plateau. Core MD00-2375G was taken at a midlatitude site during the ANTAUS cruise conducted in 2000 by the French R/V Marion Dufresne. Marine isotope stages (MIS) down to MIS 13 are identified, and an age model is derived from a correlation to the ice core isotopic record obtained from EPICA in Antarctica. Continuous records of abundance and size of the magnetic grains were obtained using environmental magnetism methods. Results show a strong modulation of the ACC flow intensity in response to glacial and interglacial cycles. The low abundance and the small size of magnetic grains indicate that the ACC was weak during warm stages and strong during glacial epochs. A large modulation is also observed at the sub-stage scale during the interglacials. A minimum in concentration and grain size occurs at the onset of MIS 11. At the MIS 6-5, 10-9, and possibly 12-11 transitions, observed variations suggest a mechanism involving both rapid and progressive variations of the ACC flow at deglaciations.
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Dates et versions

hal-02913796 , version 1 (09-10-2020)

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A. Mazaud, Elisabeth Michel, F. Dewilde, J. Turon. Variations of the Antarctic Circumpolar Current intensity during the past 500 ka. Geochemistry, Geophysics, Geosystems, 2010, 11 (8), pp.n/a-n/a. ⟨10.1029/2010GC003033⟩. ⟨hal-02913796⟩
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