Temporal evolution of mineralization events in the Bohemian Massif inferred from the Re–Os geochronology of molybdenite

Abstract

Molybdenite is a common mineral accompanying Sn–W, Au, and base metal mineralizations located in different geotectonic units of the Bohemian Massif, but it is also widespread in granitoids and/or related quartz veins/pegmatites forming disseminated Mo mineralization. Thirty Re–Os ages were obtained for molybdenite samples from the Bohemian Massif to provide constraints on the timing and duration of mineralization event(s) within the framework of previously published geochronological data for the host and/or associated rocks. The obtained data for Sn–W–(Li) deposits in the Erzgebirge metallogenetic province indicate the predominance of one and/or multiple short-time mineralization events taking place between ∼319 and 323 Ma, with the exception of the Krupka deposit associated with the Altenberg–Teplice caldera where the data may suggest prolonged activity until ∼315 Ma. The ages of the Pb–Zn–(Au–Mo) Hůrky u Rakovnika and Fe–Cu–As Obři důl mineralizations from the exocontacts of the Cista pluton and Krkonose-Jizera Plutonic Complex, respectively, provide evidence for synchronous emplacement of the ore and the associated granitic rocks. In contrast, the Padrť Fe–As–Mo mineralization postdates the age of the associated Padrť granite. Disseminated Mo mineralization in Cadomian and Variscan granitoids and/or related to quartz veins/pegmatites provides Re–Os ages that overlap with the previously published geochronological data for the host rocks, suggesting coeval evolution. Molybdenite samples from the Sazava suite granites of the Central Bohemian Plutonic Complex (CBPC) have resolvable younger ages than their host granites, but similar to the age of spatially related Au mineralization which is associated with the latest evolution of the CBPC.