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Communication Dans Un Congrès Année : 2005

HOLOCENE climate, landuse change and sedimentation in the Taligny marsh (Parisian basin, France)

Résumé

The Taligny marsh is located downstream in the Négron River catchment (southwestern Parisian basin). 33 boreholes performed in the marsh show that it contains a maximum thickness of 5.80 m sediments. Their composition varies from a sandy-gravely end in the lower part of the pile to a peaty end in the upper part, the silty phase being the most abundant in the whole sediment store. The sedimentation has been continuous since at least 4360 yrs cal. BC. The accumulation rates of organic matter (TaOM) on one hand and of mineral matter (TaMM) on the other were calculated in g.m-2.yr-1 from cores located in the middle of the marsh (47° 07'812 N; 0° 11'494 E). These values have been correlated with that of the pollen and malacofauna analysis, and to the palaeoclimate data (temperature: T and precipitation: P). There is no significant negative correlation between TaOM and TaMM during the Upper Holocene. For exemple, high values of TaMM can be synchronous with high values of TaOM, particularly during the Subatlantic. OM accumulation does not depend on the climate variations expressed by P. The high values of TaOM are clearly related to Alnus forest clearance and to its substitution by Cyperaceae and paludicol taxa in the marsh (Iron and Middle Ages). Cyperaceae and paludicol taxa development results in an increase of OM supply on the soil surface and the rising of the water table, confirmed by the malacofauna data, due to the evapotranspiration decrease. MM accumulation, mainly related to the sediment yield by the catchment, does not show any one-to-one significant relation neither to climatic parameters (P or T) nor to the vegetation assemblages (forest vs. meadows or cultivation). TaMM was higher during period of cultivation development (dry and warm Neolithic, and humid cold or cool second part of the Middle Age and Modern times). TaMM was lower and little varying during the other periods (Bronze, Iron, Gallo-roman and first part of the Middle Age) due to the antagonistic effects or the little variations of the climatic parameters and the landuse (forest vs. meadows).The hydrodynamic during periods of fen development (mainly during the Middle Age) seems to have been little favorable to the retention of suspended matter in the marsh, even if the sediment yield was high in the catchment.
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Dates et versions

hal-00089067 , version 1 (09-08-2006)

Identifiants

  • HAL Id : hal-00089067 , version 1

Citer

Jean-Jacques Macaire, Jacques Bernard, Christian Di Giovanni, Florent Hinschberger, N. Limondin-Lozouet, et al.. HOLOCENE climate, landuse change and sedimentation in the Taligny marsh (Parisian basin, France). International Conference : The Fluvial System - past and present dynamics and controls., 2005, Bonn, Germany. pp.42. ⟨hal-00089067⟩
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