Tracking atmospheric and riverine terrigenous supplies variability during the last glacial and the Holocene in central Mediterranean
1Géosystèmes, UMR8217, CNRS – Université Lille 1, 59655 Villeneuve d'Ascq, France
2Laboratoire des Sciences du Climat et de l'Environnement, laboratoire Mixte CNRS-CEA-UVSQ, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France
3Ecole Pratique des Hautes Etudes, Environnements et Paléoenvironnements Océaniques, UMR5808, CNRS – EPOC, Université Bordeaux I, 33405 Talence, France
4Laboratoire des Interactions et Dynamique des Environnements de Surface (IDES), UMR8148, CNRS – Université de Paris-Sud, Bât 504, 91405 Orsay Cedex, France
5Environnements et Paléoenvironnements Océaniques, UMR5808, CNRS – EPOC, Université Bordeaux I, 33405 Talence, France
Abstract. The objectives were to retrace the eolian and fluvial terrigenous supplies in a sediment core from the Sicilian-Tunisian Strait by coupling mineralogical, grain-size and geochemical approaches, in order to get informations on the atmospheric versus riverine contributions to sedimentation on the southern side of central Mediterranean since the last glacial. The eolian supply is dominant over the whole interval, excepted during the sapropel S1 when riverine contribution apparently became significant, and particles provenance has been modified since Last Glacial. Saharan contribution increased during the Bølling-Allerød, evidencing the persistence of aridity over North Africa although the northern Mediterranean already experienced moister and warmer conditions. The Younger Dryas is marked by proximal dust inputs highlighting intense regional eolian activity. A southward migration of dust provenance toward Sahel occurred at the onset of the Holocene, likely resulting from a southward position of the Inter Tropical Convergence Zone, probably associated with a large-scale atmospheric reorganization. Finally, a peculiar high terrigenous flux associated with drastic modifications of the mineralogical and geochemical sediment signature occurred during the sapropel S1, suggesting the propagation of fine-particles derived from major floodings of the Nile River – resulting from enhanced rainfall on northeastern Africa – and their transportation across the Sicilian-Tunisian Strait by intermediate water-masses.