Paleobiological evidence of depositional conditions in the Salt Member, Gessoso-Solfifera Formation (Messinian, Upper Miocene) of Sicily

The micropaleontology of clayey layers within halite and kainite bodies in the Salt Member of the Lower Evaporitic Complex, in the Messinian (uppermost Miocene) Gessoso-Solfifera Formation, has been studied in samples taken from Racalmuto and Realmonte salt mines on the southern coast of Sicily. Rich paleobiological associations have been observed of (on the whole) well preserved foraminifers, nannoplankton, dinoflagellate cysts and pollen grains. The integrated analyses point to several normal-marine influxes that interrupted the formation of the evaporite deposits. The greatest influx of marine water (in probable correspondence with high relative sea level) occurred during the deposition of the earliest Unit C. Based on these data, a time-scale of the Salt Member deposition may be proposed for the first time, placing the salt deposition between isotope stages TG20 and TG22, in the interval 5.72 to 5.75 Ma. The micropaleontology indicates that salt deposition took place under warm and dry conditions characteristic of tropical to subtropical climates, and that there was no significant climatic change associated with the Salinity Crisis.