High-pressure metamorphism in the Kharbey metamorphic complex (Polar Urals)

Abstract

Glaucophane-bearing rocks — indicators of high-pressure metamorphism — were earlier found in the Polar Urals in the Neoproterozoic deposits of the Nyarovey series, in the northern part of the Marunkeu eclogite-amphibolite-gneiss complex, and in the foot of the ultramafic massifs of the Main Ural Fault (MUF) zone. We have discovered high-pressure rocks in the western endocontact of the Kharbey amphibolite-gneiss complex, where they are represented by garnet-glaucophane, garnet-glaucophane-barroisite rocks and garnet-barroisite amphibolites formed during progressive zonal metamorphism. From the western boundary of the complex to the east, temperature gradually increases from 400—480 °C (for garnet-glaucophane rocks) to 495—570 °C (for garnet-glaucophane-barroisite rocks and garnet-barroisite amphibolites) at a pressure of 11—16 kbar. We determined that the high-pressure metamorphism had an areal distribution within the Kharbey metamorphic complex and, apparently, marked the Paleozoic subduction-collision processes of formation of Uralides.