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

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doi: 10.5194/cp-4-333-2008
Author(s): Dickson, Alexander J.; Leng, Melanie J.; Maslin, Mark Andrew
Author Affiliation(s): Primary:
University College London, Department of Geography, London, United Kingdom
Other:
British Geological Survey, United Kingdom
University of Nottingham, United Kingdom
Volume Title: Climate of the Past
Source: Climate of the Past, 4(4), p.333-344. Publisher: Copernicus, Katlenburg-Lindau, International. ISSN: 1814-9324
Note: In English. Part of special issue No.14, Marine isotope stage 11, edited by Tzedakis, C., McManus, J. and Wolff, E., http://www.clim-past.net/special_issue14.html; published in Climate of the Past Discussion: 5 June 2008, http://www.clim-past-discuss.net/4/667/2008/cpd-4-667-2008.html; accessed in November, 2009. 53 refs.; illus., incl. 3 tables, sketch map
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.
Year of Publication: 2008
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Antarctica; Arctic Ocean; Assemblages; Atlantic Ocean; Benthic taxa; Bermuda Rise; C-13/C-12; Cape Basin; Carbon; Carbon dioxide; Cenozoic; Cores; Deep-water environment; Dome C; EPICA; Foraminifera; Glacial environment; Interglacial environment; Invertebrata; Isotope ratios; Isotopes; Labrador Sea; Last glacial maximum; Leg 162; Leg 172; Leg 175; Leg 177; MIS 10; MIS 11; MIS 12; Microfossils; Middle Pleistocene; North Atlantic; North Atlantic Deep Water; Norwegian Sea; O-18/O-16; ODP Site 1063; ODP Site 1085; ODP Site 1089; ODP Site 980; Ocean Drilling Program; Oxygen; Paleo-oceanography; Paleocirculation; Paleoclimatology; Paleotemperature; Pleistocene; Protista; Quaternary; Rockall Bank; South Atlantic; Southern Ocean; Stable isotopes; Wilkes Land
Coordinates: S292228 S292228 E0135924 E0135924
N334111 N334111 W0573654 W0573654
Record ID: 2010021581
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