Zlaté Hory in the Silesia – the largest ore district in the Jeseníky Mts., Czech Republic. Part 2: C. Geology D. Minerology E. Geochemistry of stable isotopesArticle PDF
Zlaté Hory in the Silesia – the largest ore district in the Jeseníky Mts., Czech Republic. Part 2: C. Geology D. Minerology E. Geochemistry of stable isotopes
C. The Zlaté Hory ore district is a part of the metamorphosed Devonian volcano-sedimentary complex which is situated on the southern slope of a Variscan accretion zone with an intensive granitization. This zone occurs at the intersection of two regional zones in the area characterized by a complex history with the polyphase deformation and metamorphism. The evolution of the volcano-sedimentary cycle and subsequent tectonic and metamorphic events, have contributed to the development of the mineralization and to the structure of the orebodies.
D. Stratabound sulphidic ore bodies with predominance of pyrite (± sphalerite, galena, chalcopyrite, pyrrhotite and accessories: gold, arsenopyrite, tetrahedrite, bornite, chalcocite) are displaced in the form of disseminated, banded (layered) and massive textures, too. The relicts of primary volcano-sedimentary textures (collomorph pyrite, globular sphalerite) are present. Sulphides are accompanied with quartz, dolomite, plagioclase and barite. During the metamorphic ore reworking new mineral phases as native bisrnuth, cosalite, freibergite, Ba-muscovite, celsiane, norsethite and cymrite appeared. The recrystallization and rnetamorphic mobilization is expressed in increasing Ni + Co contents in pyrite and Ag, Se and Te in galena. The hypergenne alteration lead to the formation of more than 40 supergene minerals (allophane, cerussite, schwertmannite and others).
E. The strontium and sulphur isotopes of sulphate from the Zlaté Hory deposits have shown that barite was derived from the contemporaneous Devonian seawater sulphate. The oxygen in barite was modified during metamorphic processes. At least two sources of sulphur were present during the sulphide formation – hydrogen sulphide derived from marine sulphate and hydrogen sulphide leached from carbonaceous sediments. The idea on interaction of ore-forming fluids with adjacent sediments was supported by lower δ13C values of the carbonate found close to the sulphide mineralization.
Bohuslav Fojt, Department of Mineralogy, Petrology and Geochemistry, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
Jana Hladíková, Czech Geological Survey, Geologická 6, 152 00 Praha 5 – Barrandov, Czech Republic
František Kalenda, ProGeoConsulting, Kostelní 13, 793 76 Zlaté Hory v Jeseníkách, Czech Republic