Formation mineralogy and P-T conditions of amphibolites of the Nyartin metamorphic complex and Mankhobeyskaya suite of the Subpolar Urals

The article presents the results of studying the amphibolites of the Nyartinskiy Complex and the Mankhobeyskaya Suite. Based on the petrographic and mineral features of the rocks and the chemical zoning of the garnets, two episodes of metamorphism manifestations have been established. The first episode is characterized by a higher temperature (500-620°C), corresponding to the conditions of the epidote-amphibolite facies (B3). The pressure at this stage is estimated at 6-10 kbar. The second episode corresponds to low-temperature diaphthoresis (284-318°C) in the greenschist facies (B4). Similar conditions of the rocks metamorphism of the Nyartinskiy Complex and the Mankhobeyskaya Suite confirm the idea that Mankhobeyskaya Suite is not an independent stratigraphic unit, but is a complex of low-temperature diaphtorites in rocks similar to those that compose the Nyartinskiy Complex.