P-T path of metamorphism and U-Pb monazite and zircon age of the Kitoy terrane: Implication for Neoarchean collision in SW Siberian Craton

摘要

The first data onP-Tmetamorphic conditions coupled with U-Pb monazite and zircon age obtained for the Neoarchean Kitoy granulite-gneiss terrane (SW Siberian Craton). Alumina gneisses of the Kitoy terrane indicate two-staged metamorphic evolution. The first stage of regional metamorphism (M1) occurred at high-amphibolite facies conditions atT??=??780–800??°C andP??=??8–9??kbar. The second stage (M2) belongs to MT-HT/LP type of metamorphism with the wide temperature interval 600–750??°C and pressure 2–4??kbar. Two age peaks were established on the basis of U-Pb monazite and zircon dating in garnet-anthophyllite gneisses. Both of them correspond to the Neoarchean age: the age of M1 falls into the interval of ca. 2489–2496??Ma, the age of M2 – ca. 2446–2456??Ma. The high-temperature metamorphism of the Kitoy block and nearly coeval granitoid magmatism can be an evidence for the Neoarchean collision in SW Siberian craton.