Thorium and Uranium Minerals in Adakites as Indicators of the Post-Collisional Processes in the Stanovoy Cratonic Superterrane (Russian Far East)

The Early Cretaceous post-collisional adakites of the Stanovoy superterrane in the Russian Far East are geochemically similar to adakites associated with slab destruction and break-off in collisional and post-collisional tectonic settings. The Stanovoy adakites contain microminerals of Th, U, Ag и Au in association with amphibole, biotite, feldspars, zircon, apatite, monazite, rutile, F-bearing titanite, zirconolite, ilmenite and magnetite. Textural and compositional characteristics of these micronclusions suggest formation during crustal differentiation of adakite melts derived from hybridization of sulfide-rich mafic crust under large collisional structures by deep high-temperature F–P–Ti–Zr–Th–U–REE-rich fluids. It is concluded that adakites with such microminerals may serve as indicators of post-collisional processes responsible for the formation of rare and strategic metal deposits within ancient collisional margins of the Precambrian cratons.