Oxidation of native sulfur in the Fore-Carpathian sulfur deposits in the light of isotopic and mineralogical data

Abstract

Secondary gypsum is formed as a result of sulfur oxidation in the native . sulfur deposits of the Fore-Carpathian Depression, Southern Poland. Limestones containing native sulfur exposed to the activity of atmospheric weathering easily change into gypsum. The secondary gypsum occurs as fine, dispersed crystals, crusts and crystal groups growing on the surface of rocks, which are exposed for a longer period. The newly formed gypsum differs in the sulfur isotope composition from its older generations occurring in the deposits. The differentiation of isotopic composition of secondary gypsum in relation to native sulfur is much higher than it is indicated by the experimental data. There was recorded gypsum of both lighter and heavier isotopic composition than the native sulfur. The sulfur oxidation in the deposits can proceed either inorganically or by the sulfur bacteria. There was observed the secondary gypsum which crystallized from the formation waters collected in ephemeral pools in the bottom side of the sulfur mine and the formation · of which is connected with the bloom of sulfur bacteria.