Mediterranean Sea

Messinian Salinity Crisis

Between 5.60 and 5.46 Ma, one of the most spectacular environmental crises of the Neogene period occurred in this basin: the Messinian Salinity Crisis (MSC) or the almost complete desiccation of the Mediterranean Sea. During the MSC, the Mediterranean Sea was transformed into a giant saline basin, one of the largest in the Earth’s history. The most probable cause of this event is attributed to a tectonic activity, which resulted in the narrowing and finally the closure of the last gateway which connected the Mediterranean Sea to the world ocean, leading to the almost complete isolation of the Mediterranean Basin. This dramatic event is illustrated by the deposition of thick evaporites (up to 1.5 km of gypsum and halite) in the central Mediterranean basins, and onshore, by a coeval outstanding erosion which affected the margins with a paroxysmal subaerial cutting of canyons by the most important rivers. The discovery of the central Mediterranean evaporites (DSDP Leg 13) resulted in heated discussions about the most appropriate scenario for their formation. Several models were proposed, such as: (1) the “deep desiccated basin”; (2) the “desiccated shallow water basin” and (3) the “deep non-desiccated basin”.​

Lago Mare events

In its classical concept, the “Lago Mare” biofacies succeeds the Messinian evaporites and is generally considered to mark the end of the Messinian Salinity Crisis. This biofacies is characterized by the co-occurrence of the marine and brackish fauna of Paratethyan origin in the same localities. More recently, the brackish dinoflagellate cysts found in the Mediterranean marginal basins have confirmed this biofacies. Three Lago Mare (LM) events, respectively: (a) LM1 and LM3 are identified in the peripheral basins and correspond to high sea-level connections between the Mediterranean and Paratethys before (Messinian) and after (earliest Zanclean) the paroxysmal phase of the Messinian Salinity Crisis; (b) LM2 is included within the topmost part of the Upper Evaporitic Unit in the central basins or just above it. It is speculated to originate from the overflowing (possibly dumping after barrier collapse) of the Aegean perched Basin within almost completely desiccated Eastern Mediterranean Basin that pooled Paratethyan waters during the peak of the crisis.

Cartography and biostratigraphy of seismic markers.