ABSTRACT
The 34S‰ values in the Bleiberg type deposits range from −1 to −32 with an average value close to −19.7. The lowest signatures are found in galena and sphalerite from the primary stratiform mineralization. The highest values are present in late marcasite and banded sphalerite. Sulphide samples show numerous peloids composed of central core and surrounding corona, interpreted as mineralised colonies of bacteria reducing sulphur. The core after etching reveals numerous elongated or circular µm-size bodies of individual bacteria. Bacterial colonies are mineralised with: Zn-calcite, sphalerite, pyrite, and oxysulphides.
