Elsevier

Marine Chemistry

Volume 31, Issues 1–3, 10 December 1990, Pages 123-135
Marine Chemistry

Research paper
Stable isotope study of water, gypsum and carbonate samples from the Bannock and Tyro Basins, eastern Mediterranean

https://doi.org/10.1016/0304-4203(90)90034-AGet rights and content

Abstract

Seawater and brine samples collected along vertical profiles above the Bannock and Tyro Basins (eastern Mediterranean), and gypsum samples collected by dredging and coring the anoxic section of the Bannock Basin, have been studied for their δ18O values. The following conclusions may be drawn from these data: (1) The water of the deep brines is isotopically slightly different from modern Mediterranean bottom water and might be a ‘fossil water’ possibly formed during a recent, climatically cooler stage or when the evaporation was slightly higher than nowadays. (2) The similarity between the δ18O values of the brine samples from the Bannock and Tyro Basins supports the possibility that the ages of the two basins are very close to each other. (3) Gypsum crystals on the bottom of the Bannock Basin are probably being formed by the dissolution and reprecipitation of sub-bottom (or outcropping) Messinian evaporites. This hypothesis is supported by the oxygen isotopic values exhibited by the gypsum crystallization water and by the oxygen and sulphur isotopic composition of gypsum. (4) The shells of pelagic organisms included in gypsum are probably very recent, but not contemporary, and may be referred to cooler environmental conditions.

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  • Fluid-sediment interactions at Eastern Mediterranean mud volcanoes: A stable isotope study from ODP Leg 160

    2003, Earth and Planetary Science Letters
    Citation Excerpt :

    Whereas the simple dissolution of chloride salts by any unsaturated solution would increase the Cl concentration but leave the isotopic values unchanged, a possible contribution of residual brines is expected to cause an enrichment in both 18O and D [17] (Table 2). However, the observed δD values are depleted and a δ18O value of about 2‰ for relict Mediterranean brines [18] is too close to the background value of 1.6‰ for Mediterranean seawater [19] to alter the isotopic composition significantly. Several sedimentary components have δ18O and δD values that differ significantly from the pore water composition and may, therefore, alter its isotopic composition by diagenetic reactions.

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