| Abstrakt: |
The hydrothermal mineral assemblages of Permian age were studied in rocks of immediate contact with Permian granite, as well as of granite exocontact, rocks in the granite wider surrounding, as well as Permian volcanosedimentary sequences and volcanic breccia in Gemeric unit (Internal Western Carpathians). Presented evolution of Permian mineralization in closed metamorphic-magmatic-hydrothermal (MMH) cycle is based on new mineralogical and geochemical studies of various mineralization etalons, distinguished by their genetic succession and location within the anatectic melting zone in amphibolite facies (amphibolite, granite) through epidote-amphibolite facies to biotite zone with cassiterite-tourmaline bearing greisen in the Hnilec locality. In the chlorite-apatite zone there were studied the cassiterite-tourmaline-Fe carbonates-bearing greisen in the Dlhá dolina valley and tourmaline-molybdenite-Fe carbonates-bearing greisen of the Hnilec locality. The apatite-xenotime bearing mineralization of chlorite-apatite zone occurs in stockwork of the Čučma locality and Sb-rich sulfidestourmaline- Fe carbonates in Rozabela vein. The sedimentary exhalative U-rich SedEx mineralization was studied in localities of Kurišková and Poráč in the Permian volcanosedimentary sequences of chlorite-apatite zone. In the stilpnomelane-chlorite zone, skarns were formed at the boundary of magnesite-dolomite and calcite-ankerite bodies in locality of Dlhá dolina. The body of Ca-Mg-Fe carbonates was separately formed by Mg and Fe-rich fluids that had replaced the former Silurian limestone. In these metasomatites the skarn consists of assemblage of maghemite-cassiterite-Fe carbonate-FeZnCuBiTeIn sulfides. The siderite-sulfides bearing veins having an etalon of Konštancia and Strieborná veins are distributed in the chlorite zone. Permian metamorphic-magmatic and hydrothermal cycle in the Gemeric region was a product of the final (collisional) stage of earlier subduction and related to the volcanic arc magmatism, having two stages: (1) Older cycle (281-273 Ma) producing porphyric granite (VAG), cassiterite greisen, apatite-xenotime stockworks, maghemite-cassiterite-ankerite skarn, as well as andesite (K-CAB) and U-rich SedEx mineralization in the North-Gemeric zone, having source in the upper crust. (2) Younger cycle (263-251 Ma) had the mantle influence and produced differentiated granite (syn-COLG) with cassiterite-tourmaline-Fe, as well as tourmaline-molybdenite-Fe carbonates greisens, maghemite-cassiterite-Fe carbonate-FeZnCuBiTeIn sulfides bearing skarn and related Mg-Fe metasomatites, Sb-rich sulfides-tourmaline-Fe carbonates veins, siderite-sulfides veins and rhyolite (K-CAB) with related U-Mo-Cu-rich SedEx breccia. According to the Re-Os dating of molybdenite and cassiterite there has been found that mineralization in the Permian cycle formed within an interval of 268-256 Ma and lasted 12 Ma. The igneous cycle lasted 30 Ma from 281 to 251 Ma. The primary source for Permian mineralization was represented by the lydites and stratabound sulfidic mineralization (Silurian and Devonian). Gemeric granites are of S-type and K, P, Rb, Li, Ta, Nb and mainly Sn, B and Sb-bearing. The study is focussed exclusively on Permian (late Variscan) metallogeny and does not treat with the younger Alpine period metallogenesis. [ABSTRACT FROM AUTHOR] |
