ABSTRACT
The presence in many metamorphic rocks of minerals which only form at high pressures and temperatures indicate that the rocks have, in many cases, been buried to considerable depth in the crust and have subsequently returned to the surface. Metamorphic rocks are generally classified according to the metamorphic facies to which they belong. Granofels is the name given to a massive metamorphic rock which contains no preferred alignment of mineral grains Metamorphism accompanied by deformation produces a schistosity, the oriented or planar structure seen in schists due to the parallel alignment of platy or prismatic crystals. Under higher temperature conditions of metamorphism and deformation, rocks tend to become coarser grained and develop a gneissic foliation. A crenulation is formed when a pre-existing foliation in the rock becomes deformed into a series of small folds, eventually forming a new planar feature in the rock parallel to the axial plane of the small folds.
