Alekseev, et al., reports that niobium minerals in zwitter and lithium–fluorine granite of the Verkhneurmiysky granitic massif in the Amur River region of Russia: fergusonite-(Y), euxenite-(Y), samarskite-(Yb), aeschynite, Nb-bearing wolframite, have been described and the similarity of their species composition established. The same-named and crystal-chemically allied minerals from zwitter and granite are characterized by similar complexes of such trace elements as W, REE, Mn, Fe, Pb, U, and Sc. A genetic link between Sn-bearing zwitter and Li–F granite is stated. Compositional varieties of niobium minerals in granite and zwitter reflect a change in the physicochemical conditions of mineral formation, when the magmatic stage is followed by a pneumatolytic–hydrothermal process. The post-magmatic evolution of niobium minerals is characterized by increased concentrations of Y, Pb, U, Fe and decreased concentrations of W, Ta, REE, Ti, Sc, and Th. The mineral occurrences in the western sector of the Verkhneurmiysky Cu–W–Sn cluster are appraised as promising for Nb, Y, and REE. Fergusonite, samarskite, euxenite, and Nb-bearing wolframite are indicators of rare metal mineralization.
The authors conclude that:
1) The similarity of species and chemical compositions of accessory rare metal mineralization in Li–F granites (samarskite, aeschynite, fergusonite, niobium wolframite) and zwitter (fergusonite, euxenite, niobium-bearing wolframite) of the Verkhneurmiysky massif has been established. Niobium minerals from granite and zwitter are characterized by similar compositions of admixtures: W, Y, REE, Mn, Fe, Pb, U, and Sc. The revealed trends reflect the genetic link between zwitter and Li–F granite in the Verkhneurmiysky tin-tungsten ore cluster.
2) The compositional difference between niobium minerals from granite and zwitter reflects a change in the physicochemical conditions of mineral formation upon the transition from magmatic to pneumatolytic–hydrothermal stages. The post-magmatic evolution of the niobium mineral composition is expressed as an increasing contribution of Y, Pb, U, Fe and decreasing concentrations of W, Ta, REE, Ti, Sc, and Th.
3) The presence of rare metal mineralization in zwitter associated with Li–F granite in the eastern endomorphic zone of the Verkhneurmiysky granitic massif allows us to recommend the ore occurrences in the western sector of the Verkhneurmiysky tin cluster for Nb, Y, and REE. Mineral indicators of rare metal mineralization are niobium minerals of granite and zwitter: fergusonite, samarskite, euxenite, and Nb-wolframite.
Managed & Built by I2M Consulting, LLC | © 2010-
