Bouimetarhan, Ilham; Groeneveld, Jeroen; Dupont, Lydie M; Zonneveld, Karin A F (2013): Dinoflagellate cyst assemblages, Mg/Ca based reconstructed temperatures, stable carbon isotopes, and geochemical parameters of sediment core GeoB9508-5. PANGAEA, https://doi.org/10.1594/PANGAEA.809697, Supplement to: Bouimetarhan, I et al. (2013): Low- to high- productivity pattern within Heinrich stadial 1: Inferrences from dinoflagellate cyst records off Senegal. Global and Planetary Change, https://doi.org/10.1016/j.gloplacha.2013.03.007
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In order to investigate a possible connection between tropical northeast (NE) Atlantic primary productivity, Atlantic meridional overturning circulation (AMOC), and drought in the Sahel region during Heinrich Stadial 1 (HS1), we used dinoflagellate cyst (dinocyst) assemblages, Mg/Ca based reconstructed temperatures, stable carbon isotopes (d13C) and geochemical parameters of a marine sediment core (GeoB 9508-5) from the continental slope offshore Senegal. Our results show a two-phase productivity pattern within HS1 that progressed from an interval of low marine productivity between ~ 19 and 16 kyr BP to a phase with an abrupt and large productivity increase from ~ 16 to 15 kyr BP. The second phase is characterized by distinct heavy planktonic d13C values and high concentrations of heterotrophic dinocysts in addition to a significant cooling signal based on reconstructions of past sea surface temperatures (SST). We conclude that productivity variations within HS1 can be attributed to a substantial shift of West African atmospheric processes. Taken together our results indicate a significant intensification of the North East (NE) trade winds over West Africa leading to more intense upwelling during the last millennium of HS1 between ~ 16 and 15 kyr BP, thus leaving a strong imprint on the dinocyst assemblages and sea surface conditions. Therefore, the two-phase productivity pattern indicates a complex hydrographic setting suggesting that HS1 cannot be regarded as uniform as previously thought.
Latitude: 15.498333 * Longitude: -17.948000
Date/Time Start: 2005-06-15T13:51:00 * Date/Time End: 2005-06-15T13:51:00
Datasets listed in this publication series
- Bouimetarhan, I; Groeneveld, J; Dupont, LM et al. (2013): Foraminiferal carbon isotopes and Mg/Ca-based temperature records of sediment core GeoB9508-5. https://doi.org/10.1594/PANGAEA.809579
- Bouimetarhan, I; Groeneveld, J; Dupont, LM et al. (2013): Palynological analysis of sediment core GeoB9508-5. https://doi.org/10.1594/PANGAEA.809550