Journal of

GEOsciences

  (Formerly Journal of the Czech Geological Society)

Original Paper

Zimák, Zdeněk Losos, Novotný, Petr Dobeš, Hladíková

Study of vein carbonates and notes to the genesis of the hydrothermal mineralization in ithe Moravo-Silesian Culm

Journal of the Czech Geological Society, volume 47 (2002), issue 3-4, 111 - 122

Hydrothermal mineralizations of Variscan and Post-Variscan ages with high proportion of carbonates (calcite, dolomite-ankerite, siderite), are widespread in the Moravo-Silesian Culm (Lower Carboniferous clastic flysch) formations at the north-eastern margin of the Bohemian Massif. Results of a detailed study (chemistry, isotopic composition, fluid inclusions) of vein carbonates are presented in this work.
Two basic types of hydrothermal vein mineralization were distinguished. Older Variscan epithermal (to mesothermal ?) syntectonic mineralization is represented by quartz-calcite veins with clinochlore-chamosite chlorite, rare pyrite. Younger hydrothermal mineralization is formed mainly by carbonates (calcite, subordinate dolomite-ankerite series, rare siderite) and quartz. Sulphides are represented by galena, sphalerite, chalcopyrite, pyrite and locally marcasite. Both types of mineralization often occur in one vein.
Oxygen and carbon isotopic composition of carbonates of the two types of hydrothermal mineralization (δ¹³C between -1.4 and -9.7 ‰ PDB, δ¹⁸O usually between -12.8 and -19.2 ‰ PDB) is probably indicative of formation of the hydrothermal solutions from meteoric waters during their circulation in the Culm sedimentary formations. A strong dependence between mineral composition and the character of the surrounding sediments is typical for the studied mineralizations.