Age Benchmark of Granulite Metamorphism in the Angara–Kan Block, South Yenisei Range: Evidence from Zircon Dating of Postcollisional Granite–Aplite Dikes

Abstract

The paper presents isotope–geochronological data on zircons from a granite–aplite dike that cuts garnet–hypersthene gneisses of the Kuzeyev unit of the Neoarchean–Paleoproterozoic Kan Group in the southern extension of the Ishimba–Tatarka regional shear zone, Kan River. The morphology and internal structure of most of the zircon grains indicate that the zircons are metamorphic and xenogenic and were captured by the acidic magma from the host rocks when the magma intruded the granulites. Based on these data, the obtained Paleoproterozoic U–Pb age of 1784 ± 6 Ma can be interpreted as the age of granulite metamorphism. The interpretation of available geological and isotopic data confirms a postcollisional age of the aplite, which was emplaced nearly synchronously with the formation of anorogenic leucogranites of the late phase of the Tarak complex, during the final stage of the formation of the Nuna supercontinent.