Assemblages of Microinclusions of Fe–Ti Oxides, Apatite, Sulfates, and Sulfides in Pyroxenites, Gabbroids, and Adakitic Granitoids from the Gabbrovy Massif as Precursors of Iron Oxide–Copper–Gold and Iron Oxide–Apatite Mineralization in the Stanovoy

Mesozoic basic–ultrabasic massifs and spatially associated adakites in the central part of the Stanovoy superterrane reflect the long (more than 100 Ma) history of development of the active continental margin associated with subduction of the oceanic crust of the Mongol–Okhotsk Basin, continental collision, and the widespread development of postcollisional tectonomagmatic processes along the southern edge of the Siberian Craton. A striking example of such plutonic complexes is the Gabbrovy massif, consisting of pyroxenites, amphibole–biotite gabbro, and gabbro–anorthosites with mixed subduction–postcollisional geochemical characteristics, intruded by postcollisional adakitic granitoids formed through melting of a thickened mafic subcontinental crust. Intrusive rocks of the Gabbrovy massif contain microinclusions of iron–titanium oxides (magnetite, titanomagnetite, ilmenite), apatite, sulfates (barite, celestite), and sulfides (pyrite, chalcopyrite, sphalerite, Pb, Cu, Fe sulfides) in association with Zn–Cu–Ag alloys, titanite (including cerium-bearing), and thorite. Associations of these microminerals were previously identified by us as the ITOASS (iron–titanium oxide–apatite–sulfate–sulfide) assemblage, characteristic of the early magmatic stages of the formation of iron oxide–copper–gold (Andean type) and apatite–magnetite (Kiruna type) deposits. The presence of ITOASS microinclusions in basic–ultrabasic massifs and adakites of the central part of the Stanovoy superterrane indicates the possibility of detecting ore occurrences of the Andean and Kiruna types in the eastern part of the Stanovoy superterrane.