Intermediate Granite Rocks

In igneous petrology an intermediate composition refers to the chemical composition of a rock that has 52 63 wt sio 2 being an intermediate between felsic and mafic compositions.

Intermediate granite rocks.

Felsic intermediate mafic and ultramafic. And those with less than 45 percent are ultramafic. Felsic and mafic rocks. These groups refer to differing amounts of silica iron and magnesium found in the minerals that make up the rocks.

Syenite diorite and monzonite. Ultramafic rocks are dominated by olivine and or pyroxene. Those with between 45 and 55 percent silica are mafic. Other articles where intermediate rock is discussed.

Intermediate rocks are roughly even mixtures of felsic minerals mainly plagioclase and mafic minerals mainly hornblende pyroxene. Granite is composed mainly of quartz and feldspar with minor amounts of mica amphiboles and other minerals this mineral composition usually gives granite a red pink gray or white color with dark mineral. It forms from the slow crystallization of magma below earth s surface. For igneous rock the composition is divided into four groups.

Typical intermediate rocks include andesite dacite and trachyandesite among volcanic rocks and diorite and granodiorite among plutonic rocks. Granite is a light colored igneous rock with grains large enough to be visible with the unaided eye. The name comes from two related rocks to which granodiorite is an intermediate. Granodiorite is a plutonic igneous rock formed by intrusion of silica rich magma which cools in batholiths or stocks below the earth s surface.

It is usually only exposed at the surface after uplift and erosion have occurred. Mafic rocks are dominated by plagioclase and pyroxene even if you can t see them with the naked eye and smaller amounts of olivine. And 65 percent silica are intermediate.