Chlorite is also a common metamorphic mineral, usually indicative of low-grade metamorphism. Metamorphic grade is an informal indication of the amount or degree of metamorphism. These processes include partial melting, crystallization, fractionation, metamorphism, weathering, and diagenesis. They are generally formed from precursor mineral assemblages typical of blueschist-facies metamorphism. Greenschist facies results from low temperature, moderate pressure metamorphism. Frequently, rock formations that undergo orogeny are severely deformed and undergo metamorphism. It represents a common type of regional pelitic orogenic metamorphism. Rocks in the paragneiss of the Monte Rosa Nappe record eclogite-facies metamorphism. Periclase is usually found in marble produced by metamorphism of dolomitic limestones. Deformation twinning is a common result of regional metamorphism. It occurs as veins in serpentinite and contact metamorphism aureoles. The whole peninsula was formed by intense tectonics (faults, overthrusts and regional metamorphism). Fourth is a layer of sediments derived from weathering land with low-grade metamorphism. Mineral alteration is distinctly different than the rock alteration process metamorphism. The oxygen sinks include reduced gases and minerals from volcanoes, metamorphism and weathering.