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Poster De Conférence Année : 2009

Interest of hydrogeological modelling in the interpretation of pollen proxies for palaeo-climate reconstitution: example from Senegalese niayes

Résumé

Niaye ecosystems shelter an azonal relic guinean vegetation under sahelian climate. Pollinic proxy records in cores show that a guinean closed forest installed at 10500BP* during the African Humid Period (AHP), and thrived under a somewhat degraded state until 2500 BP. Sub-surface water flow brings today the necessary water to these interdunal depressions, keeping some of them flooded, with a distribution linked to water stress. But the equilibrium was different in the past between underground water availability, surface run-off, varying regional hydrogeology, sea level. and distance, and pluviometry (annual and seasonal). This study aims at: - explaining how gallery forest persisted through the mid-Holocene dry episode (7500-4000BP), though in a degraded state, - examining the dynamics of the end of the Tafolian humid pulsation (4000-3000BP), when vegetation turned to sahelian - weighting the relative strength of the different forcings, notably the transience of higher-scale hydrogeology - finally, examining the pertinence of a (sometimes assumed) distinctive relationship between observed pollens and regional climate.
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hal-02936881 , version 1 (11-09-2020)

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  • HAL Id : hal-02936881 , version 1

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Pascal Maugis, Lazar Aguiar, Christophe Grenier, Aurélien Claude, Raphaël Léger. Interest of hydrogeological modelling in the interpretation of pollen proxies for palaeo-climate reconstitution: example from Senegalese niayes. Histoire climatique des déserts d'Afrique et d'Arabie, 2009, Paris, France. ⟨hal-02936881⟩
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