A first variety of this type of metasomatism affects only enclaves within a granitoid. Synonyms to the word metasomatism are metasomatose and metasomatic process. It exhibits a high grade gneiss terrane characterized by metasomatism. Many komatiites are highly altered and serpentinized or carbonated from metamorphism and metasomatism. Magnesite can be formed via talc carbonate metasomatism of peridotite and other ultramafic rocks. In modal metasomatism, new minerals are formed. The magmas of Ashikule probably did not form under the influence of water metasomatism. Changes in composition can be caused by processes such as weathering or metasomatism (hydrothermal alteration). Skarns or tactites are hard, coarse-grained metamorphic rocks that form by a process called metasomatism. In this case the metamorphism grades into metasomatism. Bustamite typically results from metamorphism of manganese-bearing sediments, with attendant metasomatism. Metasomatism will change the original composition. Hydrogen-ion metasomatism is the process that causes phyllic alteration. Metasomatism does further affect rocks derived from magma chamber walls. Metasomatism can occur via the action of hydrothermal fluids from an igneous or metamorphic source.