1 Sous presse (2007) dans Quaternary Science Reviews Dansgaard-Oeschger climatic variability revealed by fire emissions in southwestern Iberia A.-L. Daniau* a,b , M.F. Sánchez Goñi b , L. Beaufort c , F. Laggoun-Défarge d , M.-F. Loutre e , J. Duprat b , a CNRS UMR5199 PACEA, Institut de Préhistoire et Géologie du Quaternaire, Université Bordeaux1, bât B18, Avenue des Facultés, 33405 TALENCE Cedex, France al.daniau@ipgq.u-bordeaux1.fr b CNRS UMR5805, EPOC, EPHE, Université Bordeaux1, bât B18, Avenue des Facultés, 33405 TALENCE Cedex, France mf.sanchezgoni@epoc.u-bordeaux1.fr j.duprat@epoc.u-bordeaux1.fr c CEREGE, UMR6635, Université Aix Marseille III (Paul Cézanne), Europôle de l’Arbois, BP80, 13545 Aix en Provence Cedex 04, France beaufort@cerege.fr d ISTO, UMR6113, CNRS-Université d’Orléans, BP 6759, 45067 Orléans cedex 2, France fatima.laggoun-defarge@univ-orleans.fr e Université catholique de Louvain, Institut d’Astronomie et de Géophysique Georges Lemaître, 2 chemin du Cyclotron, B-1348 Louvain-la Neuve, Belgium marie-France.loutre@uclouvain.be *Corresponding author: E-mail address : al.daniau@ipgq.u-bordeaux1.fr (Anne-Laure DANIAU) CNRS UMR5199 PACEA, Institut de Préhistoire et Géologie du Quaternaire, Université Bordeaux1, bât B18, Avenue des Facultés, 33405 TALENCE Cedex, France Tel : +33 5 40 00 29 82 Fax : +33 5 40 00 84 51 Abstract Paleoenvironmental records in Europe describing paleofires extending back to the Last Interglacial have so far been unavailable. Here we present paleofire results from the combined petrographic and automated image analysis of microcharcoal particles preserved in marine core MD95-2042 retrieved off southwestern Iberia and covering the last climatic cycle. The variability of microcharcoal concentrations reveals that the variability of fire emissions is mainly imprinted by the 23 000 yrs precessional cycle. A focus on the Last Glacial Period further shows that paleofires follow the variability of Dansgaard-Oeschger oscillation and Heinrich events and, therefore, parallel the variability of atmospheric temperatures over Greenland detected in ice cores. There is no evidence for fire increase related to human activity. The variability of fire emission by-products for the Last Glacial Period is interpreted in terms of changes in biomass availability. Low fire activity is associated with periods of drought which saw the development of semi-desert vegetation that characterised stadial periods. Fire activity increased during wetter interstadials, related to the development of open Mediterranean forests with more woody fuel availability. Keywords: marine sequence; microcharcoal; fire; Iberian Peninsula; Dansgaard-Oeschger oscillations; Heinrich events