Rare-Metal Mineralization of Sn Occurrences in the Area of Li–F Granites, Verkhneurmiysky Ore Cluster, Amur Region

Abstract

The by-products of the Far East Sn deposits related to Li–F granites include trace elements. The petrography and mineral composition of the Sn-bearing metasomatites of the Verkhneurmiysky ore cluster (VUOC) of the Amur region (feldspatites, greisens, zwitters, turmalinites, and chloritites) and the multistage complex rare-metal (RM) mineralization of the Sn occurrences in area of Li–F granites are studied. The minerals of strategic metals (Nb, Ta, W, Y, REE (from La to Lu), Be, Li, Rb, Zr, Hf, In, Sc, Se, Cd, and Te) are found. The RMs occur as minerals (fergusonite, plumbopyrochlore, allanite, monazite, roquesite, sakuraiite, etc.) and isomorphic substitution in the ore (wolframite; cassiterrite; Cu, Sn, Fe, Mo, Zn, and Pb sulfides; native bismuth; etc.) and rock-forming (fluorite, siderophyllite, muscovite, and epidote) minerals. Some RMs (Y, REEs, Nb, In, and Sc) most frequently occur in Sn-bearing metasomatites. The RM minerals formed during the VUOC evolution (from the premineral feldspatite to the postmineral chloritite stage) with decreasing intensity of RM mineral formation and compositional evolution from lithophile to chalcophile RMs: (LREE, Zr, Hf) → (W, Nb, Ta, Y, HREEs, Sc) → (Sn, In, Cd, Se, Te). The formation of the VUOC RM mineralization was caused by magmatic, metasomatic, and crystal chemical factors. The possible complex exploration of the Far East Sn deposits is shown for areas of Li–F granites.