Geology and Re-Os molybdenite geochronology of the Kurišková U-Mo deposit (Western Carpathians, Slovakia)

Abstract

*Corr esponding author The Kuriskova U–Mo deposit from the Gemeric Unit of the Western Carpathians (Slovakia) is an example of polygenic deposit whose origin involved several events: endogenous, related to magmatism/volcanism, and exogenous, associated with precipitation from meteoric hydrothermal fluids in repeated tectonically-driven (fold & thrust and shear zones) channel ways penetrating the Permian Huta volcano–sedimentary complex. Sources of the U–Mo mineralization were multiple: (a) molybdenite was derived directly from juvenile hydrothermal fluids related to igneous activity, (b) the U mineralization formed from meteoric fluids circulating through altered and metamorphosed basaltic and rhyolitic volcanics intercalated by clastic sediments (sandstones and mudrocks), which interacted in an arid to humid climate with organic and carbonate substances within Permian basin. The principal ore-forming minerals are uraninite, coffinite, molybdenite and apatite with rare orthobrannerite and powellite. Two basic mineralization forms are present: (a) tabu lar – “stratiform like” and (b) stockwork intraformational and/or dislocation stockworks in shear zones. The Re–Os molybdenite dating confirmed crystallization from igneous source in Late Permian (Lopingian; 257.2 ± 3.0 Ma to 255.6 ± 3.7 Ma) for massive vein mineralization, whereas the superimposed U remobilization within shear zones occurred in the Triassic/Jurassic period. The Kuriskova U–Mo deposit represents a polygenic endo/exogenous hydrothermal deposit of the Permian/Paleo-Alpine age, with metals sourced in Permian volcanosedimentary rocks that were leached by shear zone-related meteoric fluids.