Conference:
4th Congress “Environment and Identity in the Mediterranean – the Messinian Salinity Crisis”, Corte, France, 19-25 July, 2004.
Authors:
Séverine Fauquette, Jean-Pierre Suc, Adele Bertini, Speranta-Maria Popescu, Sophie Warny, Naima Bachiri Taoufiq, Maria-Jesus Perez Villa, Georges Clauzon, Jaqueline Ferrier, Hafida Chikhi, Danica Subally, Najat Feddi.
Abstract:
Quantifying the climate of the Mediterranean region during the Messinian salinity crisis will help to better understand climate forcing on this event. The “Climatic Amplitude Method” was used for reconstructing climate from Neogene pollen data, conceived especially for periods devoid of modern vegetation analogue. Twenty Messinian and Lower Zanclean pollen sequences are available in the Mediterranean region. Most of them do not cover the whole Messinian interval, particularly those along the Mediterranean shorelines were sedimentation was interrupted during the desiccation. In contrast, sedimentation was almost continuous in such areas as Morocco (Atlantic side), the Adriatic coast (Po valley included) and momentarily the Black sea. Pollen diagram reveal a high regional variability and a southward increase in herb frequency. Open and dry environments existed in the southern Mediterranean region prior to, during and after the salinity crisis. Trees developed in areas close to mountains such as Po Valley, Cerdanya and the Black sea region. Most variations are constrained by the fluctuations of Pinus pollen amounts, indicating eustatic variations. Climatic quantifications from pollen data does not show obvious climatic changes due to the desiccation of the Mediterranean Sea especially in the dry and warm southwestern Mediterranean area (Sicily, southern Spain and North Africa). At Maccarone, along the Adriatic Sea, a decrease in temperatures of the coldest month and, less importantly, a decrease in mean annual temperature, correspond to a drastic vegetation change. These temperature variations are assumed to be controlled by regional environmental changes rather than to reflect cooling. Some migrations of plants probably occurred as a response to the Mediterranean dessication. But the climatic contrast that has probably existed at that time between the central Mediterranean and the peripheral areas might be amplified. Climatic reconstructions from pollen data in the western mediterranean area shows that the climate is not the direct cause of the Mediterranean desiccation, as the Mediterranean region had experienced continuously high evaporation long before the crisis.