부산대학교 도서관

• We present the first strontium isotope data from the Paratethys domain in Messinian Salinity Crisis times. • Paratethys paced the hydrological changes in the Mediterranean during the MSC. • The Mediterranean 87Sr/86Sr values during MSC Stage 3 appear dominated by Paratethys waters. • Evaporation of a low-salinity surface layer rich in calcium and sulfate saturates with respect to gypsum at a salinity of 40. • Paratethys outflow should be considered as additional driver for the cyclic gypsum beds of the Mediterranean MSC. During the so-called Messinian Salinity Crisis (MSC: 5.97-5.33 Myr ago), reduced exchange with the Atlantic Ocean caused the Mediterranean to develop into a "saline giant" wherein ∼1 million km3 of evaporites (gypsum and halite) were deposited. Despite decades of research it is still poorly understood exactly how and where in the water column these evaporites formed. Gypsum formation commonly requires enhanced dry conditions (evaporation exceeding precipitation), but recent studies also suggested major freshwater inputs into the Mediterranean during MSC-gypsum formation. Here we use strontium isotope ratios of ostracods to show that low-saline water from the Paratethys Seas actually contributed to the precipitation of Mediterranean evaporites. This apparent paradox urges for an alternative mechanism underlying gypsum precipitation. We propose that Paratethys inflow would enhance stratification in the Mediterranean and result in a low-salinity surface-water layer with high Ca/Cl and SO 4 /Cl ratios. We show that evaporation of this surface water can become saturated in gypsum at a salinity of ∼40, in line with salinities reported from fluid inclusions in MSC evaporites. [ABSTRACT FROM AUTHOR]