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

Uranium (Nuclear Minerals) / Exploration, Mining, Marketing, & Acquisitions

Alekseeva, et al., report that 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 pre-mineral feldspatite to the post-mineral 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.

The authors conclude that:

 1) The multistage complex RM mineralization of the Sn occurrences of the Verkhniy Urmi ore cluster have been studied in the area of the Li–F granites. The minerals of strategic RMs have been identified: Nb, Ta, W, Y, REEs (from La to Lu), Be, Li, Rb, Zr, Hf, In, Sc, Se, Cd, and Te.

2) Two modes of occurrences of RMs have been determined: RM minerals (fergusonite, euxenite, plumbopyrochlore, allanite, zircon, monazite, xenotime, roquesite, sakuraiite, etc.) and RM-bearing ore (wolframite, cassiterite, Cu, Sn, Fe, Mo, Zn, and Pb sulfides, native bismuth, etc.) and rock-forming (fluorite, siderophyllite, muscovite, epidote) minerals. Frequently observed RMs have been identified in the composition of the Sn metasomatites: Y, REE, Nb,
In, Sc.

(3) The RM minerals formed during the entire evolution of the Verkhneurmiysky ore cluster: from the pre-mineral stage of feldspatites to the post-mineral stage of chloritites including the syn-mineral stage of zwitters and tourmalinites. The intensity of RM mineral formation decreases from the early to late stages, as well as the compositional evolution from lithophile to chalcophile RMs: (LREE, Zr, Hf) → (W, Nb, Ta, Y, HREE, Sc) → (Sn, In, Cd, Se, Te).

(4) The formation of RM mineralization of the Verkhneurmiysky ore cluster was affected by magmatic, metasomatic, and crystal chemical factors. The mineralogical–geochemical study of the occurrences of the Verkhneurmiysky ore cluster show possible complex exploration of the Far East Sn deposits in the areas of Li–F granites.