DECOMPRESSION MINERAL MICROTEXTURES IN GRANULITES OF THE IRKUT BLOCK ( <i>Sharyzhalgai uplift of the Siberian Platform</i>)
This paper presents mineral reactions in metapelites and estimations of PT -conditions of metamorphism for paragranulites of the Irkut block of the Sharyzhalgai uplift (Siberian Platform). The geothermometeric data based on exchange reactions and the contents of Na in cordierite and Ti in zircon indicate that the peak temperature of metamorphism reached ca. 800 °C at 6–7 kbar. The observed mineral reactions suggest that the pressure decreased to ca. 3 kbar at the retrograde stage of metamorphism.