Charakteristika pseudofulguritu ze Žatčan u Brna, Česká republika
Článek v PDFCharacterization 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.
Eva Víšková, Department of Mineralogy and Petrography, Moravian Museum, Zelný trh 6, 659 37 Brno, Czech Republic, eviskova@mzm.cz
Stanislav Houzar, Department of Mineralogy and Petrography, Moravian Museum, Zelný trh 6, 659 37 Brno, Czech Republic
Karel Slavíček, Department of Geological Sciences, Masaryk University, Brno, Kotlářská 2, 611 37 Brno, Czech Republic