Chovan M., Mikuš T., Prcúch J. & Bača B., 2021: Assemblage of Ag–Pb–Bi±Cu sulfosalts from the Bieber vein, Banská Štiavnica deposit, Slovakia. Acta Geologica Slovaca, 13, 2, 191–198.

Assemblage of Ag–Pb–Bi±Cu sulfosalts from the Bieber vein, Banská Štiavnica deposit, Slovakia

Martin Chovan¹, Tomáš Mikuš², Ján Prcúch³ & Boris Bača³

¹Department of Mineralogy, Petrology and Economic Geology, Faculty of Natural Sciences, Comenius University, Ilkovičova 6, 842 15 Bratislava, Slovak Republic; chovanmmm@gmail.com
²Earth Science Institute, Slovak Academy of Sciences, Ďumbierska 1, 974 01 Banská Bystrica, Slovakia
³Slovenská Banská, Ltd., 966 61 Hodruša-Hámre 388, Slovakia

Abstract

An interesting assemblage of Ag-Pb-Bi±Cu-sulfosalts was found at the Bieber vein in Banská Štiavnica. Their occurrence is related to the deepest part of the vein, characterized by a high copper content and the predominance of chalcopyrite over other base metals sulfides. Rare members of lillianite series (ourayite, eskimoite and “schirmerite”) are associated with schapbachite and matildite – galena exsolutions. Berryite, arcubisite and acanthite, polybasite and unnamed phase (Cu₃AgPbBi₂S₆) were also rarely found as inclusions in galena. Bi sulfosalts of the lillianite homologous series (ourayite, eskimoite, “schirmerite”) and schapbachite probably formed at temperatures around 350 °C. When the temperature was reduced below 215 °C, the sulfosalts were unstable and below 144 °C the solid solution exsolved to pure AgBiS₂ and PbS.

Key words: Western Carpathians, sulfosalts, lillianite homologous series, eskimoite, ourayite, “schirmerite”, matildite-galena exsolution

Manuscript received: 2021-01-22

Revised version accepted: 2021-11-22