Physicochemical Conditions of Metamorphism of Rocks of the Ilyinovskii Complex (Trans-Uralian Uplift): First Data

Abstract

This work presents a short description of the geological structure of the Ilyinovskii metamorphic complex. Based on the results of studying the garnet–biotite paragenesis, widespread among paragneisses and diaphthorites, two stages of metamorphic transformation of rocks were distinguished. During the Early Proterozoic, sedimentary rocks were transformed under amphibolite (cummingtonite–amphibolite) facies metamorphism (T = 530–580°C; P = 3.0–3.1 kbar); during the Late Riphean, in connection with the structural arrangement in the Southern Urals, they were metamorphosed under epidote–amphibolite facies conditions (T = 500–560°C; P = 5.4–6.0 kbar).