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Palynological evidence for climatic and oceanic variability off NW Africa during the late Holocene

Published online by Cambridge University Press:  20 January 2017

Ilham Bouimetarhan ,
Lydie Dupont ,
Enno Schefuß ,
Gesine Mollenhauer ,
Stefan Mulitza  and
Karin Zonneveld
Ilham Bouimetarhan*
Affiliation:
Department of Geosciences, University of Bremen, Klagenfurter Strasse, D-28359 Bremen, Germany MARUM - Center of Marine Environmental Sciences, University of Bremen, Leobener Strasse, D-28359 Bremen, Germany
Lydie Dupont
Affiliation:
MARUM - Center of Marine Environmental Sciences, University of Bremen, Leobener Strasse, D-28359 Bremen, Germany
Enno Schefuß
Affiliation:
MARUM - Center of Marine Environmental Sciences, University of Bremen, Leobener Strasse, D-28359 Bremen, Germany
Gesine Mollenhauer
Affiliation:
Department of Geosciences, University of Bremen, Klagenfurter Strasse, D-28359 Bremen, Germany Alfred-Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
Stefan Mulitza
Affiliation:
MARUM - Center of Marine Environmental Sciences, University of Bremen, Leobener Strasse, D-28359 Bremen, Germany
Karin Zonneveld
Affiliation:
Department of Geosciences, University of Bremen, Klagenfurter Strasse, D-28359 Bremen, Germany MARUM - Center of Marine Environmental Sciences, University of Bremen, Leobener Strasse, D-28359 Bremen, Germany
*
⁎Corresponding author. Department of Geosciences, University of Bremen, Klagenfurterstrasse, D-28359 Bremen, Germany. Tel.: +49 421 218 65138; fax: +49 421 218 4451.

E-mail address:bouimetarhan@uni-bremen.de (I. Bouimetarhan).

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Abstract

Pollen and organic-walled dinoflagellate cyst assemblages from core GeoB 9503-5 retrieved from the mud-belt (∼ 50 m water depth) off the Senegal River mouth have been analyzed to reconstruct short-term palaeoceanographic and palaeoenvironmental changes in subtropical NW Africa during the time interval from ca. 4200 to 1200 cal yr BP. Our study emphasizes significant coeval changes in continental and oceanic environments in and off Senegal and shows that initial dry conditions were followed by a strong and rapid increase in humidity between ca. 2900 and 2500 cal yr BP. After ca. 2500 cal yr BP, the environment slowly became drier again as indicated by slight increases in Sahelian savannah and desert elements in the pollen record. Around ca. 2200 cal yr BP, this relatively dry period ended with periodic pulses of high terrigenous contributions and strong fluctuations in fern spore and river plume dinoflagellate cyst percentages as well as in the fluxes of pollen, dinoflagellate cysts, fresh-water algae and plant cuticles, suggesting “episodic flash flood” events of the Senegal River. The driest phase developed after about 2100 cal yr BP.

Keywords

PalaeoceanographyPalaeoenvironmentPollenOrganic-walled dinoflagellate cystSenegal RiverMud-belt
Type
Research Article
Information
Quaternary Research , Volume 72 , Issue 2 , September 2009 , pp. 188 - 197
Copyright
University of Washington

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