Badania izotopowe siarczanów, węglanów oraz wody krystalizacyjnej gipsów w utworach miocenu Przedkarpacia

Abstract

STUDIES ON ISOTOPES OF SULFIDES, CARBONATES AND CRYSTALLIZATIONAL WATER OF GYPSUM IN MIOCENE ROCKS OF THE PRZEDKARPACIE REGION Summary This report presents new, more precise stable isotope data and their interpretation for evaporite sulfates, sulfur- bearing carbonates and water of crystallization of gypsum in the Miocene formation of the Carpathian Foredeep, SE Poland. The isotopic data (δ34S, δ18O, δ13C and δD) give further support for general model of epigenetic origin of the native sulfur ore deposits in this area and they cast some new light on geochemical processes which took place during deposition of gypsum and subsequent alteration. S and O isotope abundances in evaporites are markedly uniform and consistent with their marine origin. Carbon isotopes in carbonates provide information on source of organic matter responsible for sulfate reduction, and it is concluded that the major source was methane generated in underlying strata, while oxygen isotope ratios show meteoric origin of water, in which underwent the deposition of the carbonates. The waters of crystallization of gypsum widely range in their D/H and 18O/16O ratios, depending on location, cristal size, and degree of erosion. The most negative delta values has been found in gypsum-anhydrite within Basznia deposit, which likely was due to partial regypsification of anhydrite in contact with water of glacial origin.