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Molybdenite-tungstenite association in the tungsten-bearing topaz greisen at Vítkov (Krkonoše-Jizera Crystalline Complex, Bohemian Massif): indication of changes in physico-chemical conditions in mineralizing system

  1. 1.
    0449610 - GLÚ 2016 RIV CZ eng J - Článek v odborném periodiku
    Pašava, J. - Veselovský, F. - Drábek, M. - Svojtka, Martin - Pour, O. - Klomínský, J. - Škoda, R. - Ďurišová, Jana - Ackerman, Lukáš - Halodová, P. - Haluzová, Eva
    Molybdenite-tungstenite association in the tungsten-bearing topaz greisen at Vítkov (Krkonoše-Jizera Crystalline Complex, Bohemian Massif): indication of changes in physico-chemical conditions in mineralizing system.
    Journal of Geosciences. Roč. 60, č. 3 (2015), s. 149-161. ISSN 1802-6222. E-ISSN 1803-1943
    Grant CEP: GA ČR GA13-15390S
    Institucionální podpora: RVO:67985831
    Klíčová slova: LA-ICP-MS * EMPA * molybdenite * tungstenite * transitional Mo–W and W–Mo disulfides * Bohemian Massif
    Kód oboru RIV: DB - Geologie a mineralogie
    Impakt faktor: 1.326, rok: 2015

    At Vítkov, sparse molybdenite occurs within tungsten mineralization hosted by topaz greisen in orthogneiss in the envelope of the Variscan Krkonoše-Jizera granite Pluton (northern Bohemian Massif). Mineralogical study showed that sulfide mineralization started with precipitation of arsenopyrite followed by molybdenite, tungstenite, transitional Mo- and W-dominated disulfides and concluded by pyrite. Textural relationships between molybdenite and tungstenite imply that tungstenite was formed during several stages related to molybdenite bending and fracturing. Laser Ablation Inductively Coupled Mass Spectrometry (LA-ICP-MS) analyses of Re-poor (less then 0.3 ppm) molybdenite showed extreme concentrations of W (up to 26 558 ppm) accompanied by Ag, As, Bi, Pb, Se, Te and other metals. Electron microprobe analyses of inclusions-free molybdenite confirmed the abundance of W (ca 0.5 wt. %) and tungstenite showed ca4 wt. % Mo, indicating a substitution of Mo4+ for W4+. Stability and phase relationships between molybdenite and tungstenite and locally identified transitional Mo- and W-dominated disulfidic phases suggest that tungstenite crystallization was triggered by a decrease in fO2 below WO2-WO3- buffer that followed after molybdenite precipitation. Tungstenite zoning and sharp tungstenite-molybdenite contacts indicate disequilibrium during their formation.
    Trvalý link: http://hdl.handle.net/11104/0251138

     
     
Počet záznamů: 1  

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