Chemical composition of bottom waters and interstitial waters from the Eastern Mediterranean

Chemical composition of bottom waters and interstitial waters and of more than 40 specimens of brines with salinities 50-270 g/kg in cores of bottom sediments up to 5 m long collected during Cruise 2 of R/V Moskovskiy Universitet southeast of the Crete Island are investigated. The brines and high-salinity interstitial waters were investigated in several rift valleys with subzonal orientation (Tyro and Kreteus valleys) associated with the crest of the Mediterranean swell, which is complicated by salt dome tectonics. Increase of salinity in cores containing diatomaceous-sapropelic oozes was accompanied by sulfate reduction and generation of H2S. All water samples and brines belonged to the magnesium subtype of the sulfate category. Two genetic varieties of interstitial waters in the epigenetic class are clearly distinguishable: 1) brines resulting from leaching of halite and mixing with NaCl of seawater, and 2) waters and brines rich in MgCl2. These data indicate that Messinian evaporites have an significant effect on the present-day lithohydrosphere of the Mediterranean.