Hydrothermal mineralization at the locality Pindula near Frenštát pod Radhoštěm (Silesian Unit, Outer West Carpathians)Article PDF
Hydrothermal mineralization at the locality Pindula near Frenštát pod Radhoštěm (Silesian Unit, Outer West Carpathians)
Studied locality Pindula is situated in the Beskydy Mts. which are formed by the Silesian Unit. Dark clayey siderite (i.e., pelosiderite) concretions present in Lower Cretaceous grey claystones belonging to the Lhotka Formation host the hydrothermal mineralization. Occurrence of hydrothermal minerals is restricted only to “desiccation fissures” within the pelosiderite. The hydrothermal assemblage is very simple, composed of older siderite (showing identical chemical composition as the siderite in host pelosiderite) and younger brown calcite. Homogenization temperatures (Th) of primary fluid inclusions hosted by calcite are between 54 and 105 °C and fluids have low salinities (0.9–1.9 wt. % NaCl equiv.). Chondrite-normalized REE pattern of calcite shows negative Eu anomaly indicating crystallization in reducing environment. Both siderite and calcite are characterized by positive calculated fluid δ18O values (ca. +4 to +8 ‰ SMOW) and negative fluid δ13C values (-18 to -21 ‰ PDB). The origin of the mineralization is evidently related to the diagenetic processes that took place in the host rocks.
Martin Polách, Zdeněk Dolníček, Department of Geology, Faculty of Science, Palacký University, tř. Svobody 26, 771 46 Olomouc, e-mail: Giraffe@seznam.cz; firstname.lastname@example.org
Karel Malý, Vysočina Museum Jihlava, Masarykovo nám. 55, 586 01 Jihlava, Czech Republic, e-mail: email@example.com