Bahr, André; Nürnberg, Dirk; Schönfeld, Joachim; Garbe-Schönberg, Carl-Dieter (2011): Stable isotope and geochemical analyses of sediment core SO164-17-2 from the southern Florida Straits. PANGAEA, https://doi.org/10.1594/PANGAEA.759379, Supplement to: Bahr, A et al. (2011): Hydrological variability in Florida Straits during marine isotope stage 5 cold events. Paleoceanography, 26, PA2214, https://doi.org/10.1029/2010PA002015
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Modeling and proxy studies indicate that a reduction of Atlantic Meridional Overturning Circulation (AMOC) strength profoundly impacts temperatures and salinities in the (sub)tropical Atlantic, especially on subsurface levels. While previous studies focused on prominent periods of AMOC reduction during the last deglaciation, we aim to test whether similar reconfigurations of the subtropical hydrography occurred during the moderate climatic alterations punctuating the last interglacial, Marine Isotope Stage (MIS) 5. Here, we present temperature and salinity records from a Florida Straits core by combining d18O and Mg/Ca analyses on surface (Globigerinoides ruber, white) and deep-dwelling (Globorotalia crassaformis) foraminifera, covering MIS 5 in high resolution. The data reveal increasing salinities at intermediate depths during interglacial cooling episodes, decoupled from relatively stable surface conditions. This probably indicates the spatial expansion of saline Subtropical Gyre waters due to enhanced Ekman downwelling and might also point to a changed density structure and altered geostrophic balance in Florida Straits. Notably, these oceanographic alterations are not consistently occurring during periods of AMOC reduction. The data suggest that the expansion of gyre waters into Florida Straits was impeded by the increasing influence of Antarctic Intermediate Water (AAIW) from MIS 5.5 to ~107 kyr BP. Afterwards, increasingly positive benthic d13C values imply a recession of AAIW, allowing the temporary expansion of Gyre waters into Florida Straits. We argue that the inferred transient subtropical salt accumulation and warm pool expansion might have played a pivotal role in reinvigorating meridional overturning and dampen the severity of interglacial cold phases.
Latitude: 24.080667 * Longitude: -80.889000
Date/Time Start: 2002-06-02T08:08:00 * Date/Time End: 2002-06-02T08:42:00
SO164-17-2 * Latitude: 24.080667 * Longitude: -80.889000 * Date/Time Start: 2002-06-02T08:08:00 * Date/Time End: 2002-06-02T08:42:00 * Elevation Start: -954.0 m * Elevation End: -955.0 m * Penetration: 15 m * Recovery: 11.76 m * Location: Florida Strait * Campaign: SO164 (RASTA/GOLDFLOS) * Basis: Sonne * Method/Device: Piston corer (PC) * Comment: tube bent
Datasets listed in this publication series
- Bahr, A; Nürnberg, D; Schönfeld, J et al. (2011): (Table A1) Holocene stable isotope and geochemical data obtained on sediment core SO164-17-2. https://doi.org/10.1594/PANGAEA.759367
- Bahr, A; Nürnberg, D; Schönfeld, J et al. (2011): (Table A2) Stable isotope and geochemical data obtained on sediment core SO164-17-2 for the time interval comprising Marine Isotope Stage (MIS) 5. https://doi.org/10.1594/PANGAEA.759374
- Bahr, A; Nürnberg, D; Schönfeld, J et al. (2011): (Table A3) Semi-quantitative frequency of Globorotalia menardii in sediment core SO164-17-2. https://doi.org/10.1594/PANGAEA.759267
- Bahr, A; Nürnberg, D; Schönfeld, J et al. (2011): (Table A4) Stable oxygen isotope data obtained on Globigerinoides sacculifer in sediment core SO164-17-2. https://doi.org/10.1594/PANGAEA.759279
- Bahr, A; Nürnberg, D; Schönfeld, J et al. (2011): (Table A5) Radiocarbon dates performed on sediment core SO164-17-2. https://doi.org/10.1594/PANGAEA.759376