Abstract
Gypsum and anhydrite from the Upper Miocene (Messinian) evaporites of the Mediterranean Basin were analysed for their coprecipitated-ion compositions. The concentrations of Mg, Na, K, Sr and Cl in gypsum and anhydrite samples from DSDP Leg 42a, sites 372, 374 and 376 and from boreholes Yafo-1, Ashdod-2, Talme-Yafe-3 and Afiq-1 from the Coastal Plain of Israel were used to calculate the composition of the brines from which these calcium sulfate minerals were deposited, or in which they have undergone recrystallization or phase transformation. Results reveal basic differences between the eastern, central and western Mediterranean basins during the last stage of the Messinian salinity event. The western Mediterranean and the Ionian Basin were characterized by marine brines during most of the second stage of the salinity event (Upper Evaporite member). During this period the eastern Mediterranean basins were fed with brines of continental origin. These brines are characterized by high Ca concentrations relative to seawater brines. One core from the eastern Mediterranean (Yafo-1) indicated that anhydrite was deposited along the continental margin of the eastern Mediterranean from brines of marine composition, which evolved into Carich continental brines following a marine regression.
Published Version
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