Mineral composition and trace element characteristics of pegmatites from Smilovene, Sredna Gora Mountain, Bulgaria

The study is focused on the Smilovene pegmatites, targeting estimation of their rare element potential. These bodies bring rare-metal mineralization with LCT geochemical signature and mineral association of albite, oligoclase, microcline, quartz, muscovite, beryl, garnet, fluorapatite, zircon, columbite, samarskite-(Y), monazite-(Ce), magnetite, and gahnite. Late chlorite, prehnite, titanite, and bertrandite were established. Beryl is characteristic with high amounts of FeO, Na2O, MgO, ZnO, F, and traces of Cs, and Li. Spessartine-almandiness is enriched in Y2O3, TiO2, ZnO, P2O5, REE, Li, Ge, Ga with typical inclusions of apatite, monazite-(Ce), zircon, magnetite, gahnite, ilmenite, uraninite, and Nb-bearing phases. Significant contents of HfO2, UO2, REE2O3, ThO2, and traces of Y, Sc, Ta, Zn, Nb, Be, Li and inclusions of uraninite and cheralite are common in zircon. Minor amounts of Cl, MnO, Y2O3, and REE2O3 attribute to fluorapatite. Except the dominant Ce2O3 in monazite-(Ce), La2O3, ThO2, and Gd2O3 are established. The presence of rare-metal mineralization in the Smilovene pegmatites confirms their potential as a critical/strategic elements concentrator, feasible for further exploration and possible exploitation.