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Mid-depth South Atlantic Ocean circulation and chemical stratification during MIS-10 to 12 : implications for atmospheric CO2

Dickson, A.J.; Leng, Melanie; Maslin, M.A.. 2008 Mid-depth South Atlantic Ocean circulation and chemical stratification during MIS-10 to 12 : implications for atmospheric CO2. Climate of the Past, 4. 333-344.

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Abstract/Summary

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.

Item Type: Publication - Article
Programmes: BGS Programmes 2008 > NERC Isotope Geoscience Laboratory
Additional Information. Not used in RCUK Gateway to Research.: Climate of the Past is an interactive open access journal of the European Geosciences Union
Additional Keywords: Climate, South Atlantic Ocean, Carbon dioxide - environmental aspects, Atmospheric chemistry
NORA Subject Terms: Earth Sciences
Date made live: 10 Feb 2009 13:04
URI: http://nora.nerc.ac.uk/id/eprint/6048

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