High-pressure mafic granulites of the South Muya Block (Central Asian Orogenic Belt)

Аннотация

Mineralogical, petrographic, and geochemical studies of mafic granulites of the South Muya Block (Central Asian Orogenic Belt) have been carried out. The granulite protoliths were olivine- and plagioclase- rich cumulates of ultramafic–mafic magmas with geochemical affinities of suprasubduction rocks. The isotope–geochemical characteristics of the granulites indicate the enriched nature of their source, associated with recycling into the mantle of either ancient crust or oceanic sediments, or intracrustal contamination of melts at the basement of the ensialic arc. Formation of garnet-bearing parageneses has occurred during high-pressure granulite metamorphism associated with accretion in the eastern part of the Baikal–Muya composite terrane.