Huang, Enqing; Mulitza, Stefan; Paul, André; Groeneveld, Jeroen; Steinke, Stephan; Schulz, Michael (2012): Benthic foraminiferal δ¹⁸O and Mg/Ca studies of sediment cores off tropical NW Africa. PANGAEA, https://doi.org/10.1594/PANGAEA.802610, Supplement to: Huang, E et al. (2012): Response of eastern tropical Atlantic central waters to Atlantic meridional overturning circulation changes during the Last Glacial Maximum and Heinrich Stadial 1. Paleoceanography, 27, https://doi.org/10.1029/2012PA002294
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Benthic foraminiferal d18O and Mg/Ca of sediment cores off tropical NW Africa are used to study the properties of Atlantic central waters during the Last Glacial Maximum (LGM) and Heinrich Stadial 1 (HS1). We combined our core top data with published results to develop a new Mg/Ca-temperature calibration for Planulina ariminensis, which shows a Mg/Ca-temperature sensitivity of 0.19 mmol/mol per °C. Estimates of the LGM and HS1 thermocline temperatures are comparable to the present-day values between 200 and 400 m water depth, but were 1.2-1.5°C warmer at 550-570 m depth. The HS1 thermocline waters (200-570 m depth) did not show any warming relative to the LGM. This is in contrast to previous climate model studies, which concluded that tropical Atlantic thermocline waters warmed significantly when Atlantic meridional overturning circulation was reduced. However, our results suggest that thermocline temperatures of the northeastern tropical Atlantic show no pronounced sensitivity to changes in the thermohaline circulation during glacial periods. In contrast, we find a significant increase in thermocline-water salinity during the LGM (200-550 m depth) and HS1 (200-400 m depth) with respect to the present-day, which we relate to changes in the wind-driven circulation. We infer that the LGM thermocline (200-550 m depth) and the HS1 upper thermocline (200-400 m depth) in the northeastern tropical Atlantic was ventilated by surface waters from the North Atlantic rather than the southern-sourced waters. This suggests that the frontal zone between the modern South Atlantic and North Atlantic Central Waters was probably shifted southward during the LGM and HS1.
Median Latitude: 8.915498 * Median Longitude: -14.921403 * South-bound Latitude: 8.875500 * West-bound Longitude: -14.961000 * North-bound Latitude: 8.948000 * East-bound Longitude: -14.889333
Date/Time Start: 2005-06-26T10:26:00 * Date/Time End: 2005-06-26T23:12:00
Datasets listed in this publication series
- Huang, E; Mulitza, S; Paul, A et al. (2012): (Table 2) Radiocarbon ages of sediment core GeoB9532-2, GeoB9533-2/3, and GeoB9534-5. https://doi.org/10.1594/PANGAEA.802550
- Huang, E; Mulitza, S; Paul, A et al. (2012): (Table 3) Planulina ariminensis δ¹⁸O and Mg/Ca, the predicted d18O of calcite and the calcification temperature of core top samples, as well as temperature, salinity, Delta[CO3**2-]calcite of bottom waters. https://doi.org/10.1594/PANGAEA.802561
- Huang, E; Mulitza, S; Paul, A et al. (2012): (Table 5) LGM and HS1 Planulina ariminensis Mg/Ca and δ¹⁸O results of four gravity cores. https://doi.org/10.1594/PANGAEA.802569