Acta Musei Moraviae

Characterization of pseudofulgurite from Žatčany near Brno, Czech Republic

Pseudofulgurite from Žatčany near Brno originated after a fall of high voltage cables (22 kV) at several intermittent places where they touched the ground (partly anthropogenic loam-sandy sediment with gravel admixture). Branched, tubular and irregular aggregates, up to 10 cm in size, were formed in similar way as some fulgurites. Pseudofulgurite is brown-black in color, with numerous bubbles of the order of mm in size, in the case of tubular shapes with a central rounded and square channel. It consists of several types of glasses, including rare lechatelierite. They contain sporadically submicroscopic metal balls composed of native Fe, alternatively with a proportion of P, Ni, Si, Co and Cr, demonstrating a strongly reduced environment. Rather rare crystalline phases have the composition of Ca-Fe-Al-Si (±Ti), also relics of quartz and sporadic biotite can be observed locally. A lower K₂O / Na₂O ratio of 2.53–0.13 and a relatively high proportion of highly volatile S may also indicate a relatively lower melting point.