Association of sulfate and sulphide minerals as a possible paragenesis in sedimentary basins

It has been established, that in marine sediments of different ages an association of sulfate and sulphide minerals can be formed not only as a derivative of low-temperature hydrothermal processes, but also as a result of biochemical transformation of bottom pelitic sediments, enriched with organic matter. A prerequisite for this is the combination of a low free oxygen content in silt waters with the presence of a specific sulfate-reducing microbial community, which uses sulfur from aminoacids and prosthetic groups of organic residues as electron acceptors, which ensures that sulfate-ions in sea water are sufficient to precipitate sulfates, since they are not spent on the crystallization of sulphides.