Conference:
EEDEN, Dinoflagellate cysts: promising markers of Mediterranean–Paratethys relationships, 17-20 April 2004, Lyon, France.
Author:
Jean-Pierre Suc, Georges Clauzon, Speranta-Maria Popescu.
Abstract:
Central Paratethys seems to have applied a strong influence to the Mediterranean during the Messinian salinity crisis, i.e. during the so-called Lago Mare event. This facies is characterised by the presence of a brackish shallow water fauna (mollusks: Congeria, Dreissena, Melanopsis, etc.; ostracods: Cyprideis pannonica gr., Loxoconcha, Tyrrhenocythere, etc.) of Paratethyan affinity in many Mediterranean localities (Ruggieri, 1967; Cita & Colombo, 1979). More recently, dinocysts as Galeacysta etrusca and some Impagidinium spp., the usual endemic Paratethyan species of the uppermost Miocene (Müller et al., 1999), have been regularly found in the Mediterranean (Corradini & Biffi, 1988) and added to the Lago Mare biofacies (Bertini et al., 1995). It has been proposed that the Lago Mare event was caused by a “capture” of Paratethyan waters by the almost desiccated Mediterranean Basin (Hsü et al., 1973, 1977), the process of such a phenomenon being still poorly understood (Cita, 1991). Recently, several influxes of Mediterranean nannoplankton have been recorded in the Dacic Basin (Central Paratethys) (Marunteanu and Papaianopol, 1998) and well-calibrated in the Global Polarity Time Scale (Snel et al., in press). New studies in the western Dacic Basin have suggested that these transient relationships between the Mediterranean Sea and the Central Paratethys have not been restricted to only one direction (Clauzon et al., accepted). A new understanding of the Lago Mare facies is proposed: it would correspond to a high-sea level exchange between the two basins. Two similar Lago Mare events would have occurred: in the Late Messinian (just before the deep Mediterranean Basin desiccation, and in the Earliest Pliocene (just after the salinity crisis). A review of the Mediterranean Lago Mare sections is discussed according to the two proposed groups. This interpretation is consistent with the two step model of the Messinian salinity crisis (Clauzon et al., 1996).