Mafic Minerals In Granite

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.

Mafic minerals in granite.

Common examples of mafic minerals include olivine biotite hornblende. In addition such a study of mafic silicates and opaque minerals can indicate rela tive oxidation states within granitic plutons e g cza. 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. Common mafic rocks include basalt and gabbro.

Mafic rock in geology igneous rock that is dominated by the silicates pyroxene amphibole olivine and mica. In terms of chemistry mafic rocks are on the other side of the rock spectrum from the so called felsic rocks. Granite is a felsic composed of light coloured feldspars and silica minerals intrusive rock. Common rock forming mafic minerals include olivine pyroxene amphibole biotite and other micas augite and the calcium rich plagioclase feldspars.

The most common felsic rock is granite which represents the purified end product of the earth s internal differentiation process. Common felsic minerals include quartz muscovite mica and the orthoclase feldspars. Felsic minerals are usually light in color and have specific gravities less than 3 0. It is formed by the slow cooling and crystallisation of magma below the earths surface in a pluton.

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