HR: 1330h
AN: PP42A-0854    [PDF]
TI: Rapid Eolian Events Within The Last Glacial Loess Series of Europe (EOLE project)
AU: * Rousseau, D
EM: denis@dstu.univ-montp2.fr
AF: Universite Montpellier II-CNRS, Institut des Sciences de l'Evolution, pl. Bataillon, case 61, Montpellier, 34095 France
AU: * Rousseau, D
EM: denis@dstu.univ-montp2.fr
AF: Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964 United States
AU: Antoine, P
EM: Pierre.Antoine@cnrs-bellevue.fr
AF: CNRS, Laboratoire de Geographie Physique, 1, Place Aristide Briand, Meudon, 92195 France
AU: Hatt‚, C
EM: Christine.Hatte@lsce.cnrs-gif.fr
AF: CNRS-CEA, Laboratoire des Sciences du Climat et de l'Environnement UMR 1572 CEA/CNRS Bƒt 12, Domaine du CNRS, Avenue de la Terrasse, Gif-sur-Yvette, -91198 France
AU: Moine, O
EM: omoine@isem.univ-montp2.fr
AF: Universite Montpellier II-CNRS, Institut des Sciences de l'Evolution, pl. Bataillon, case 61, Montpellier, 34095 France
AU: Lang, A
EM: lang@liv.ac.uk
AF: University of Liverpool, Department of Geography, Liverpool, L69 7ZT United Kingdom
AU: Fontugne, M
EM: Michel.Fontugne@lsce.cnrs-gif.fr
AF: CNRS-CEA, Laboratoire des Sciences du Climat et de l'Environnement UMR 1572 CEA/CNRS Bƒt 12, Domaine du CNRS, Avenue de la Terrasse, Gif-sur-Yvette, -91198 France
AU: Zoeller, L
EM: Ludwig.Zoeller@uni-bayreuth.de
AF: Universitaet Bayreuth, Lehrstuhl Geomorphologie, Bayreuth, 95440 Germany
AB: The EOLE project focuses on the impact of millennial climatic variations (Dansgaard /Oeschger) and abrupt events (Heinrich), on the loess environments of Western and Central Europe between 30 and 15ka BP ($50\deg$N transect between $2\deg$ and $17\deg$E). The evidence of rapid climatic events in the loess sequences is based on their physical (grain-size, CaCO3, Iron, magnetic susceptibility) and biogeochimical (mollusks, organic carbon, $\delta13C$) characterizations, within the best-developed sequences (high-resolution 1 sample/5 cm; 10 to 15 m in thickness). The main results have been obtained in the Nussloch reference sequence (Rhine valley, Germany) where cyclic variations appear within the Upper Pleniglacial from high-resolution grain-size and MS analyses. These variations are mainly underlined by the %20-50$\mu$m$\wedge$%$<$20$\mu$m ratio (grain-size index GSI) which is interpreted as an indirect proxy of the a dynamics: high values within pure typical loess ("L?ss Events" L1 to L8)/ low values in the various tundra gley layers G1 to G8. Our investigations show that, during the Upper Pleniglacial, the loess deposition is basically characterized by a succession of rapid sedimentation phases (especially during Heinrich events 2 and 3), separated by stops (or strong reduction) in the a flux. According to OSL and 14C dating, a correlation between GSI index and the dust record from GRIP or GISP II ice cores is proposed. In addition, the cyclicity of the loess record seems to represent the expression, in continental environments, of the 1500 years cycles described in North Atlantic sediments. In parallel, the analysis of the13C of loess organic matter and of the malacological assemblages at Nussloch shows a close correspondence with the d18O from GRIP. Finally these results show that the high frequency climatic variability that characterizes the North Atlantic and Greenland records during the LGM had a strong impact on sedimentation and on terrestrial environments of Western and Central Europe.
DE: 1530 Rapid time variations
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting