The purplish grey orthogneiss displays indistinct foliation and migmatisation fabrics, which have been blurred during recrystallisation under granulite facies P-T conditions and subsequent static hydrous retrogression in amphibolite facies. The island Talerulik is visible in the far distance. The supracrustal association forms layers and enclaves in grey gneiss and may comprise two or more age groups. 3000 Ma, most likely by partial melting of wet and hot tholeiitic basaltic rocks subducted in a convergent plate setting.
Most dioritic gneiss is c.
220 Ma older. Intense deformation and metamorphism accompanied the 3000 Ma magmatic accretion. Thrusts along amphibolite-orthogneiss contacts were succeeded by large recumbent isoclines, upright to overturned folds, and local domes with granitic cores. Syntectonic granulite facies metamorphism is thought to be due to heat accumulation by repeated injection of tonalitic magma. Strong ductile deformation produced steep linear belts before the thermal maximum ceased, whereby folds were reorientated into upright south-plunging isoclines.