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Since the discovery of calcareous nannofossils, dinoflagellate cysts and planktonic foraminifers in deposits from the Dacic Basin, intensive research has been performed in order to evidence which gateway this microplankton used to connect Paratethys and the Mediterranean prior and after the Messinian Salinity Crisis (MSC). Such a gateway is also to be regarded at the origin of successive influxes of Paratethyan organisms (molluscs, ostracods, dinoflagellates) into the Mediterranean Basin ("Lago Mare" events). Observing that the I˙stanbul area, usually proposed for this purpose, was inefficient, we examine the succession of marine well-dated pre-MSC and post-MSC deltaic deposits through the Balkans, from northern Greece to southern Romania, that constitutes a reliable candidate for such a marine corridor, the origin of which was caused by the regional tectonic extension. The reconstructed palaeogeography for high sea level episodes that encompassed the MSC clarifies the context of the so-called North Aegean Lake. This marine gateway probably evolved as a powerful river during the peak of the MSC, contributing to the deposition of clastics in the hydrocarbon Prinos Field. A tectonically controlled subsidence to the north and south of the Skopje region caused the closure of such a gateway.

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More than a thousand specimens of Galeacysta etrusca complex from eleven Upper Miocene and Lower Pliocene localities of the Paratethyan and Mediterranean realms have been studied using a biometric approach in part relating to the degree of separation between endocyst and ectocyst. Four stable biometric groups have been statistically distinguished, the occurrence or prevalence of which appears closely linked to environmental conditions irrespective of the realm. Group “ a” is related to brackish conditions, group “ b” to marine conditions, group “ c” to freshwater, and group “ d” to high nutrient levels. Based on an accurate chronology provided by calcareous nannoplankton bioevents and recognition of the Messinian Erosional Surface, this study reveals: - the high sensitivity of Galeacysta etrusca complex for reconstructing paleoenvironments and the connection– isolation phases of basins ; - the detailed history of this species which originated in the Pannonian Basin at ca. 8 Ma before invading the Dacic Basin at about 6 Ma, then migrating into the Mediterranean during high sea-level connections (the “ Lago Mare” events just before and after the peak of the Messinian Salinity Crisis, i.e. at 5.60 and during the interval 5.48– 5.33 Ma, respectively) and, finally, into the Black Sea at 5.13 Ma ; - an improved paleogeographic reconstruction for the Mediterranean and Paratethyan realms with focus on the location of corridors and the timing of when they were active. Field observations and dinoflagellate cyst data lead us to consider that the reflooding of the Mediterranean Basin by Atlantic waters occurred at 5.48 Ma, i.e. significantly before 5.33 Ma that is the age of the Zanclean GSSP.

More than a thousand specimens of the Galeacysta etrusca taxonomical complex from eleven Upper Miocene and Lower Pliocene localities of the Paratethyan and Mediterranean realms have been studied using a biometric approach in part relating to the degree of separation between endocyst and ectocyst. Four stable biometric groups have been statistically distinguished, the occurrence or prevalence of which appears closely linked to environmental conditions irrespective of the realm. Group “ a” is related to brackish conditions, group “ b” to marine conditions, group “ c” to freshwater, and group “ d” to high nutrient levels. Based on an accurate chronology provided by calcareous nannoplankton bioevents and recognition of the Messinian Erosional Surface, this study reveals: • the high sensitivity of Galeacysta etrusca complex for reconstructing paleoenvironments and the connection– isolation phases of basins ; • the detailed history of this species which originated in the Pannonian Basin at ca. 8 Ma before invading the Dacic Basin at about 6 Ma, then migrating into the Mediterranean during high sea-level connections (the “ Lago Mare” events just before and after the peak of the Messinian Salinity Crisis, i.e. at 5.60 Ma and during the interval 5.48– 5.33 Ma, respectively) and, finally, into the Black Sea at 5.13 Ma ; • an improved paleogeographic reconstruction for the Mediterranean and Paratethyan realms with focus on the location of corridors and the timing of when they were active. Field observations and dinoflagellate cyst data lead us to consider that the reflooding of the Mediterranean Basin by Atlantic waters occurred at ca. 5.48 Ma, about 150 kyrs before the Zanclean GSSP (5.33 Ma).

Relationships between the Mediterranean and Paratethys have been debated for a long time (Senĕ s, 1973 ; Rögl and Steiniger, 1983 ; Kojumdgieva, 1987 ; Marinescu, 1992). High sealevel exchanges between these two seas are documented by the presence of: 1. marine organisms, especially calcareous nannoplankton (Mărunţeanu, 1992 ; Semenenko and Olejnik, 1995 ; Mărunţeanu and Papaianopol, 1995, 1998 ; Drivaliari et al., 1999 ; Snel et al., 2006) and marine dinoflagellate cysts (Popescu , 2006 ; Popescu et al., accepted ; Popescu and Süto-Szentai, unpublished data) in the Paratethys basins: 2. brackish endemic dinoflagellate cysts (Corradini and Biffi, 1988 ; Bertini, 1992, 2006 ; Popescu et al., 2007 ; Londeix et al., 2007), molluscs (dreissenids, lymnocardiids) and ostracods (Cyprideis pannonica group) (Cippolari et al., 1999 ; Gliozzi, 1999 ; Ghetti et al., 2002 ; Basseti et al., 2003, 2004 ; Esu et al., 2007) in the Mediterranean area, as constituents of “ Lago Mare” biofacies. Such connections are generally considered to have been reduced even interrupted in the Late Miocene, when the Mediterranean became temporarily isolated from the Atlantic Ocean. Isolation led to the Messinian Salinity Crisis, peaking with a severe drop in Mediterranean sea-level which resulted in the deposition of thick evaporites in central basins (Hsü et al., 1973 ; Rouchy and Caruso, 2006) and intense subaerial erosion of the margins (Clauzon, 1999). Two successive falls in sea-level (Clauzon et al., 1996) have been evidenced: 1. the first one, between 5.96-5.60 Ma, characterized by low amplitude, that caused the deposition of evaporites in the more-or-less isolated marginal basins and some erosion in the most proximal parts of river valleys ; 2. the second one, between 5.60 to 5.48 Ma characterized by high amplitude, that provoked the almost complete desiccation of the Mediterranean Sea and consequently evaporite deposition within central basins ; on the land a huge subaerial erosion is widely recorded as a consequence of river activity. Similar events (huge erosion) also impacted the Eastern Paratethys (Gillet et al., 2003, 2007 ; Clauzon et al., 2005) where evaporites were recently discovered (Clauzon et al., submitted). Different hypothesis concerning the gateway between Mediterranean and Paratethys were proposed, the most known concerned the “ proto-Bosporus” gateway (Hsü et al., 1973 ; Rögl and Steininger, 1983 ; Marinescu, 1992). The second possibility was trough the Balkans, an hypothesis proposed by Kojumdgieva (1987). The supposed “ proto Bosporus” gateway was tested by Popescu (2006), using the late arrival of marine dinoflagellate cysts at DSDP Site 380 in the Black Sea, that demonstrates the closure of this gateway in the earliest Zanclean. This evidence is also supported by (1) the huge erosional surface passing at the base of the Zanclean deposits in the same locality Gillet et al. (2007), (2) the reconstruction of a complex fluvial erosional network in the Dardanelles Strait and Marmara Sea area at the time of the desiccation of the Mediterranean (Clauzon et al., 2008). Using the presence of marine organisms and evidence of Gilbert-type delta fans, we demonstrate that the most probable gateway between the Mediterranean and Paratethys was trough the Balkans region (Clauzon et al., 2005, submitted ; Popescu et al., accepted). Most difficult to explain are the connections between the Paratethyan (Pannonian and Dacic) basins themselves because these two basins were already evolving towards brackish conditions before the Messinian Salinity Crisis. Previous hypotheses suggested that the corridor between the Pannonian and Dacic basins before the Messinian Salinity Crisis (i.e. at the Portaferrian) was located at the present-day Iron Gates (Archambault-Guézou, 1976 ; Marinescu, 1992). The discovery of the Messinian Erosional Surface below the Iron Gates (Clauzon et al., 2005 ; Leever, 2007) shows that this passage was cut by the proto-Danube River during the desiccation of the Mediterranean. As supported by dinoflagellate cyst records both in the Pannonian and Dacic basins, we propose a more reliable gateway in the area of the Timok Valley and Niš-Belgrade area at the Portaferrian (Popescu et al., accepted).

International audience; An integrated study combining facies analysis, multiple group biostratigraphy, identification of depositional sequences and mapping has been conducted on the Miocene Molasse Basin of the external Alps (southeastern France). The filling of the basin is described as resulting from a succession of fluvial incisions subsequently filled during marine transgressions. The major incision is dated as Latest Burdigalian and the major transgression as Langhian. This revised interpretation of the Miocene physiographic evolution of the Molasse Basin implies a re-examination of previous stratigraphic correlations within the basin

Suc Jean-Pierre, Clauzon Georges. La cyclostratigraphie astronomique : la seule approche pour subdiviser la crise de salinité messinienne. In: Documents des Laboratoires de Géologie, Lyon, n°156, 2002. STRATI 2002. 3ème congrès français de stratigraphie. Lyon, 8-10 juillet 2002. pp. 222-223.

Clauzon Georges, Fauquette Séverine, Suc Jean-Pierre. Quantification des paléoaltitudes néogènes des reliefs des Pyrénées orientales. In: Documents des Laboratoires de Géologie, Lyon, n°156, 2002. STRATI 2002. 3ème congrès français de stratigraphie. Lyon, 8-10 juillet 2002. pp. 76-77.