Native selenium as a byproduct of microbial oxidation of distorted pyrite crystals: the first occurrence in the Carpathians

Abstract

Abstract Acicular crystals of native selenium up to 30 μm long occur together with barite on the surface of goethite partial pseudomorphs after millimeter-sized pseudotetragonal-prismatic pyrite crystals in calcite veins that cross-cut Senonian sandstones of the Silesian Nappe in the western Polish Outer Carpathians. Native selenium originated from selenium apparently released during bacteria-induced oxidation of pyrite at neutral or near-neutral pH conditions. Oxidizing bacteria preferentially colonized {100} faces of pyrite relative {111} faces.