Messinian twinned selenite from the Catanzaro Trough, Calabria, Southern Italy: field, petrographic and fluid inclusion perspectives

Paratethys pacing of the Messinian Salinity Crisis: Low salinity waters contributing to gypsum precipitation?

“…(For interpretation of the colours in the figure(s), the reader is referred to the web version of this article.) isotope analyses of gypsum hydration water and the salinity of fluid inclusions in MSC-gypsum, however, indicate large freshwater inputs during gypsum formation in both Stage 1 Evans et al, 2015) and Stage 3 (Costanzo et al, 2019).…”

“…Fundamental questions remain about the trigger for gypsum formation and where in the water column it formed (De Lange and Krijgsman, 2010;Lugli et al, 2010). Classically, MSC-gypsum formation is considered to result from enhanced (seasonal) drought during precession maxima (Krijgsman et al, 2001;Topper and Meijer, 2013;Topper et al, 2014;Roveri et al, 2014b) Popov et al (2006).…”

The geochemical riddle of “low-salinity gypsum” deposits

“…Evidence for low-salinity gypsum in the Messinian Salinity Crisis comes primarily from the study of gypsum primary fluid inclusions. These suggest average salinities of gypsum parent waters equal to 16 g kg -1 in the Piedmont Basin (northern Italy) (Natalicchio et al, 2014), 32 g kg -1 in the Sorbas basin (Spain) (Evans et al, 2015) and 27 g kg -1 in in the Catanzaro Trough (southern Italy) (Costanzo et al, 2019). These values are between 14 % and 29 % of the threshold salinity at which gypsum precipitates from evaporating seawater in the "classical" scenario cited above.…”

“…1). The geochemical signature of gypsum deposited in some marginal basins (Natalicchio et al, 2014;Evans et al, 2015;Costanzo et al, 2019) suggest its formation from water masses with a salinity much lower than that (110 g kg -1 ) predicted by evaporation experiments (Usiglio, 1849;Valyashko, 1972;Herrmann et al, 1973) and thermodynamic models (Van't Hoff, 1912;Stewart, 1963;Braitsch, 1971;. In this paper, we will refer to this geochemically peculiar gypsum as "low-salinity gypsum".…”

Messinian bottom‐grown selenitic gypsum: An archive of microbial life

“…Data from fluid inclusions in bottom-grown selenitic gypsum challenged the idea that gypsum formed from hypersaline brines resulting from seawater evaporation. Instead, these data indicated that gypsum formed from low salinity waters (i.e., with low contents of Na + and Cl − ions) equivalent to 1.6 wt% sodium chloride on average (Costanzo et al, 2019;Evans et al, 2015;Natalicchio et al, 2014). The water masses probably represented a mixture of marine water, freshwater from Mediterranean rivers (Reghizzi et al, 2018), and brackish water from the Paratethys (Grothe et al, 2020).…”