Mafic rocks in the southern part of the Mylonite zone preserve remnants of a high-pressure mineral assemblage. The rocks occur as lenses in migmatized gneisses. The mineral assemblage equilibrated at high-pressure granulite facies conditions during the Sveconorwegian orogeny. Mineral textures and zoning indicate a prograde metamorphism in the amphibolite facies, equilibration at high-pressure granulite facies conditions and cooling through the amphibolite facies. In felsic segregates networks of biotite and plagioclase may represent pseudomorphs after phengite.
Large garnets show preserved prograde growth zoning.
The preservation of prograde zoning in large garnet crystals indicates that the rock was quite rapidly uplifted to lower temperatures. Along marginal parts of the mafic pods, the mineral assemblage has been reeqilibrated at amphibolite facies conditions. The rocks were thus deformed during the uplift of the Eastern Segment, at amphibolite facies conditions. Linear structures in the surrounding gneiss demonstrate a large west-vergent dip slip component. Tillbaka till toppen .