The Messinian Sicilian stratigraphy revisited: new insights for the Messinian salinity crisis

Controversies around the Messinian salinity crisis (MSC) arebecause of the difficulties in establishing genetic and stratigraphicrelationships between its deep and shallow-waterrecord. Actually, the Sicilian foreland basin shows both shallowand deep-water Messinian records, thus offering the chance toreconstruct comprehensive MSC scenarios. The Lower Gypsumof Sicily comprises primary and resedimented evaporitesseparated in space and time by the intra-Messinian unconformity.A composite unit including halite, resedimented gypsumand Calcare di Base accumulated between 5.6 and 5.55 Ma inthe main depocentres; it records the acme of the MessinianSalinity Crisis during a tectonic phase coupled with sea-levelfalls at glacials TG14-TG12. These deposits fully post-dateprimary gypsum, which precipitated in shallow-water wedgetopand foreland ramp basins between 5.96 and 5.6 Ma. Thisnew stratigraphic framework results in a three-stage MSCscenario characterized by different primary evaporite associations:selenite in the first and third stages, carbonate, halite andpotash salt in the second one associated with hybrid resedimentedevaporites.