Furutobeite and betekhtinite from the ore deposit Horní Benešov in the Nízký Jeseník Mts. – Czech RepublicArticle PDF
Furutobeite and betekhtinite from the ore deposit Horní Benešov in the Nízký Jeseník Mts. – Czech Republic
The occurrence of two rare Pb-Ag-Cu-Fe sulphides, furutobeite and betekhtinite, is described from the Devonian Zn-Pb stratiform deposit of Horní Benešov. Both minerals were found within post-metamorphic veinlets (cutting the pyrite-sphalerite-galena stratiform ore) associated with galena, digenite (both forming myrmekitic intergrowths), covellite, pearceite, stromeyerite, tennantite, quartz and barytocalcite. Aggregates of furutobeite, up to 0.4 mm, display significant substitution of Ag for Cu (0.21–1.05 apfu Ag), and slightly elevated content of Zn (0.09–0.17 apfu). Betekhtinite grains, up to X0 μm in diameter, exhibit also elevated Ag and Zn contents (0.09–0.11 and 0.01–0.08 apfu, respectively). The fluid inclusion study of associated quartz indicates the long-lasting fluid activity, which is manifested by the presence of three types of low-temperature (< 200 °C) aqueous fluids in primary fluid inclusions: 1) low-salinity Na-Mg-Cl „metamorphic“ fluids; 2) high-salinity Ca-Na-Cl fluids with high NaCl/CaCl2 ratio; 3) high-salinity Ca-Na-Cl fluids with low NaCl/CaCl2 ratio. The role of high-salinity aqueous solutions for remobilization of heavy metals from the stratiform ores, is emphasized generativy giving rise to the Ag-Cu-enriched vein assemblage.
Bohuslav Fojt, Radek Škoda, Institute of Geological Sciences, Masaryk University, 613 00 Brno, Kotlářská 2, Czech Republic, firstname.lastname@example.org, email@example.com
Zdeněk Dolníček, Department of Geology, Palacký University, 771 46 Olomouc, Třída 17. listopadu 12, firstname.lastname@example.org