Mafic Minerals In Granite

The rock texture thus determines the basic name of a felsic rock.

Mafic minerals in granite.

In addition such a study of mafic silicates and opaque minerals can indicate rela tive oxidation states within granitic plutons e g cza. Common examples of mafic minerals include olivine biotite hornblende. Felsic minerals are usually light in color and have specific gravities less than 3 0. Common mafic rocks include basalt and gabbro.

Mafic is a term used to describe both minerals that are rich in iron and magnesium and rocks that are rich in those minerals. Common rock forming mafic minerals include olivine pyroxene amphibole biotite and other micas augite and the calcium rich plagioclase feldspars. Common felsic minerals include quartz muscovite mica and the orthoclase feldspars. It is formed by the slow cooling and crystallisation of magma below the earths surface in a pluton.

In terms of chemistry mafic rocks are on the other side of the rock spectrum from the so called felsic rocks. These minerals are high in magnesium and ferric oxides and their presence gives mafic rock its characteristic dark colour. Often the species of mafic minerals is included in the name for instance hornblende bearing granite pyroxene tonalite or augite megacrystic monzonite because the term granite already assumes content with feldspar and quartz. Mafic rock is commonly contrasted with felsic rock in which.

Vey of opaque mineral assemblages and mafic mineral chemistry in the same specimens from which i and s type granite classification was developed was under taken to clarify this situation.