The terrae consist dominantly of mafic plutonic rocks. Orthoclase feldspar (KAlSiO) is a mineral commonly found in granite, a plutonic igneous rock. The Cuchivero Group consists of ash flow tuff and granitic plutonic rocks. Andesite can be considered as the extrusive equivalent of plutonic diorite. Geologists worldwide accept the diagrams as a classification of igneous, especially plutonic rocks. They show structures intermediate between those of extrusive and plutonic rocks. It is known from plutonic nepheline syenite rocks. Magnesian orthopyroxene occurs in plutonic rocks such as gabbro (norite) and diorite. These terranes consist of oceanic crust, volcanic and plutonic rock. This is the initial stage of K-metasomatism in cataclastically-deformed magmatic plutonic rocks. Leucite is common in lavas but very rare in plutonic rocks. Intrusive rocks formed at greater depths are called plutonic or "abyssal". The trachytes are often described as being the volcanic equivalents of the plutonic syenites. Mineralogical classification is most often used to classify plutonic rocks. These plutonic basement rocks are subdivided into the Hohonu, Karamea, Median and Paparoa batholiths.