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Titel |
Mid-depth South Atlantic Ocean circulation and chemical stratification during MIS-10 to 12: implications for atmospheric CO2 |
VerfasserIn |
A. J. Dickson, M. J. Leng, M. A. Maslin |
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 ; 4, no. 4 ; Nr. 4, no. 4 (2008-12-06), S.333-344 |
Datensatznummer |
250001873
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Publikation (Nr.) |
copernicus.org/cp-4-333-2008.pdf |
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Zusammenfassung |
A detailed record of benthic foraminifera carbon isotopes from the
intermediate-depth South East Atlantic margin shows little
glacial-interglacial variability between MIS-12 to MIS-10, suggesting that
Northern Atlantic deepwaters consistently penetrated to at least
30° S. Millennial-scale increases in either the mass or flux of
northern-sourced deepwaters over the core site occurred alongside reductions
in Lower North Atlantic Deep Water recorded in North Atlantic sediment cores
and show that the lower and intermediate limb of the Atlantic deepwater
convective cell oscillated in anti-phase during previous glacial periods. In
addition, a 500 yr resolution record of the Cape Basin intermediate-deep
δ13C gradient shows that a reduction in deep Southern Ocean
ventilation at the end of MIS-11 was consistent with a modelled CO2
drawdown of ~21–30 ppm. Further increases in the Southern Ocean
chemical divide during the transition into MIS-10 were completed before
minimum CO2 levels were reached, suggesting that other mechanisms such as
alkalinity changes were responsible for the remaining ~45 ppm
drawdown. |
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