Orogenic arc-related Ni-Cu-(PGE) mineralization of the Ransko massif, Czech Republic, and implications for the metallogeny of the European Variscan belt
| Autoři | |
|---|---|
| Rok publikování | 2025 |
| Druh | Článek v odborném periodiku |
| Časopis / Zdroj | Mineralium Deposita |
| Fakulta / Pracoviště MU | |
| Citace | |
| Doi | http://dx.doi.org/10.1007/s00126-025-01353-z |
| Klíčová slova | Orogenic; Gabbro; Zn-Cu; Ni-Cu-PGE; Metallogeny; Variscan |
| Popis | The Ransko (ultra)mafic massif, Bohemian Massif, Czech Republic, hosts several Ni-Cu-(PGE) deposits and peculiar Zn-Cu-Ba ores. Geochronology integrated with petrography, bulk-rock, and mineral compositions together with Sr-Nd-Pb-Hf-Os-O isotopic systematics of barren and variably mineralized (ultra)mafic lithologies as well as massive ores reveal a complex evolution of the Ransko massif and its mineralizations. The Sm-Nd and U-Pb ages obtained for gabbros and cross-cutting granite porphyry, respectively, overlap with Re-Os ages of Ni-Cu-(PGE) and Zn-Cu ores and limit the formation age of (ultra)mafic rocks and metal accumulations to similar to 370-345 Ma. Compositional variations indicate derivation of parental melts of the Ransko massif from metasomatized, Variscan sub-arc mantle and underscore the importance of assimilation-fractional crystallization and crystal accumulation processes. The Ni-Cu ores were emplaced through the gravity-driven percolation of dense sulfide liquids along previously weakened structures associated with the downward crystal fractionation. The orogenic and arc-related nature of the Ransko Ni-Cu-(PGE) mineralization shares some remarkable similarities with some other Ni-Cu deposits in the European Variscan Belt highlighting the significance of these deposits emplaced in arc-related crustal domains. Yet, the variable nature of these mineralizations indicates complex processes that happen during the emplacement and evolution of the parental magmas driving their favourable metal contents. |
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