Vlasáč J., Mikuš T., Ondrejka M., Žitňan P. & Tuček P., 2021: Supergene Pb-Cu-(Sb) mineral assemblage in abandoned epithermal deposit Rudno nad Hronom, Slovakia. Acta Geologica Slovaca, 13, 1, 107–118.

Supergene Pb-Cu-(Sb) mineral assemblage in abandoned epithermal deposit Rudno nad Hronom, Slovakia

Jozef Vlasáč¹, Tomáš Mikuš¹, Martin Ondrejka², Peter Žitňan^3,4 & Peter Tuček⁵

¹Earth Science Institute, Slovak Academy of Sciences, Ďumbierska 1, 974 01 Banská Bystrica, Slovakia; vlasac@savbb.sk, mikus@savbb.sk
²Department of Mineralogy and Petrology and Economic Geology, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 842 15 Bratislava, Slovakia; martin.ondrejka@uniba.sk
³Department of Geology and Palaeontology, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 842 15 Bratislava, Slovakia
⁴Rudné Bane, Kammerhofská 7, 969 01 Banská Štiavnica, Slovakia
⁵Prospech ltd, Križovatka 25, 969 01 Banská Štiavnica, Slovakia

Abstract

An unusual assemblage of Pb-Cu-(Sb)-(Mn) supergene minerals, represented by mottramite, phosphohedyphane, mimetite, segnitite-beudantite series, anglesite, cerussite, oxyplumboroméite, brochantite, devilline, gypsum and coronadite was recently identified at the Priečna, Johan de Deo and Anna-Zubau epithermal ore veins near Rudno nad Hronom, Štiavnické vrchy Mts., Slovak Republic. Mottramite is a rare mineral at the Rudno deposit and this is the first reported occurrence in the Western Carpathians. Also phosphohedyphane occurs only rarely at the deposit. The localized Pb2+ <--> Ca2+ substitution between phosphohedyphane and pyromorphite was observed. A large substitution between As and S was recognized on the T site in the beudantite – segnitite. Anglesite and cerussite are relatively abundant supergene minerals, especially in the proximity of primary galena relicts. Secondary Cu sulphates (brochantite and devilline) are only secondary minerals found also in macroscopic size. Brochantite forms dark green tabular crystals up to 0.1 mm. Devilline occurs as a light green-blue acicular crystals grown on brochantite. Gypsum was found with this assemblage. This is also first occurrence of coronadite in Western Carpathians.

Key words: Western Carpathians, Neogene Štiavnica stratovolcano, mottramite, phosphohedyphane, mimetite, segnitite-beudanite, coronadite

Manuscript received: 2021-02-17

Revised version accepted: 2021-05-25