Geochemical typization and sources of melts of the neoarchean ultra-potassic rhyolites of the kursk block, Voronezh crystalline massif

Abstract

Within a block of the Kursk Voronezh crystalline massif are Neoarchean high-ultrapotassic rhyolites, which by their geochemical characteristics belong to granitoids A-type and formed in intraplate post-collisional geodynamic setting. The formation of ultrapotassic melts acid composition occurred at high temperature partial melting crust, which has been enriched mantle substance bearing a potassium-containing fluids. As the crustal source of the melt could be tonalite-trondhjemite-granodiorite gneisses of the Oboyan complex and the source of the mantle material within the Kursk block can be Neoarchean metabasites, the underlying ultrapotassic rhyolites.