Climatic variability over western Sahel related to the latitudinal migration of the tropical rainbelt through the late Holocene: Evidence from palynology


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Gesine.Mollenhauer [ at ] awi.de

Abstract

AB: Pollen and dinoflagellate cyst assemblages from core GeoB9503-5 retrieved from the Senegal mud-belt are analyzed to reconstruct paleoenvironmental changes in western Sahel during the late Holocene. Our study emphasizes significant coeval changes in continental vegetation and oceanic conditions in Senegal area. Initial dry conditions were followed by a period of increased precipitation at ~ 2900 yr BP when the environment became enriched in woody plants and plants requiring wet conditions and the marine phytoplankton became dominated by dinocysts of river plume affinity. We interpret these observations as the result of enhanced Senegal River runoff and by inference, greater monsoonal humidity between ~ 2900 and 2500 yr BP which we refer to as “little humid phase”. The environment slowly became drier again, as indicated by slight increase in desert elements and at ~ 2200 yr BP, a trend towards wetter conditions is evident from the marked increase in pollen and dinocyst fluxes as well as fresh water algae and plant cuticles, defining another humid phase in Senegal. These alternating arid/humid phases during the late Holocene reflect most probably the weakening/strengthening of the African monsoon, potentially driven by the latitudinal migration of the Intertropical Convergence Zone and its associated tropical rainbelt.



Item Type
Conference (Poster)
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Not peer-reviewed
Publication Status
Published
Event Details
AGU Fall Meeting, 01 Jan 2009 - 01 Jan 2009, San Francisco.
Eprint ID
22722
Cite as
Bouimetarhan, I. , Dupont, L. , Schefuß, E. , Mollenhauer, G. , Mulitza, S. and Zonneveld, K. A. (2009): Climatic variability over western Sahel related to the latitudinal migration of the tropical rainbelt through the late Holocene: Evidence from palynology , AGU Fall Meeting, San Francisco, 2009 - 2009 .


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