The Messinian salinity crisisThe Late Miocene Messinian Salinity Crisis (MSC) affected the Mediterranean basin at about 6 Ma, representing one of the younger major environmental crises in Earth history[1]. The sedimentary record of this event consist of more than 1 million km3 of evaporites, embedded between hemipelagic deposits, and accumulated on the Mediterranean sea floor in less than 700 kyr through three depositional stages[2]. During Stage 1 (5.97 - 5.60 Ma) primary sulfate evaporites (the Primary Lower Gypsum unit, PLG) accumulated only in shallow areas, whereas euxinic shales and carbonates formed in deep basins. Stage 2 (5.60 - 5.55 Ma) was typified by subaerial exposure of shallow basins and by clastic gypsum and halite deposits in deeper basins. Stage 3 (5.55 - 5.33 Ma) was dominated by sulfate evaporites (the Upper Gypsum unit) and clastic deposits. The MSC sediments are arranged in distinct lithologic cycles composed of shale/evaporite couplets, recording climate change from humid to arid phases.
[1] Hsu et al., 1973. Nature 242, 240. [2] Roveri et al., 2014. Marine Geology 352,25-58 |