Structure and Age of the Fluorite-Beryl Raduga Deposit (West Sayan Mountains): Problem of Evaluation of the Metallogenic Potential of the Region

Resumo

The geochronological and geochemical parameters of the Raduga muscovite–fluorite–euclase–beryl deposit, located within the Kizir–Kazyr zone of rare-metal magmatism, were determined. In contrast to other deposits and ore occurrences located in this zone and represented by alkaline granites enriched in rare-metal mineralization, the formation of the Raduga deposit is associated with the metasomatic transformations of carbonate rocks. The age of this deposit, estimated by ⁴⁰Ar/³⁹Ar dating of muscovite fromberyllium fluorite–muscovite greisens, is 469.3 ± 4.5 Ma. It corresponds to the age of the ore-bearing alkaline granites. The dykes developed within the deposit are similar in composition to those within rare-metal alkaline–granite massifs, one of which is located a few kilometers from the deposit. The character of the Be–Li ore mineralization in the Raduga deposit is in good agreement with the geochemical specialization of the Early Paleozoic Kizir–Kazyr metallogenic zone. The revealed features of the relationship between the Raduga deposit and rare-metal deposits confined to alkaline granites suggest a variety of mechanisms involved in the formation of rare-metal deposits of the Kizir–Kazyr metallogenic zone. Thus, it allows us to expand the approaches for prediction and exploration of rare-metal deposits in the region.