Felsic rocks are mostly feldspar (especially K-feldspar), at least 10% quartz, and less than 15% mafic minerals (biotite, hornblende).
What minerals are felsic rocks?
The felsic minerals include quartz, tridymite, cristobalite, feldspars (plagioclase and alkali feldspar), feldspathoids (nepheline and leucite), muscovite, and corundum. Because felsic minerals lack iron and magnesium, they are generally light in colour and consequently are referred to as such or as leucocratic.
What is the difference between felsic and mafic igneous rocks?
Mafic rocks are rich in iron and magnesium, whereas Felsic rocks are rich in silica and aluminum. Mafic rocks are denser and heavier than Felsic rocks. Mafic rocks are darker in color than Felsic rocks. Lava made up of Felsic rocks is slow moving and has a higher viscosity than Mafic lava.
Is basalt felsic?
Granite and rhyolite are considered felsic, while basalt and gabbro are mafic (click here for more information on mafic and felsic).
Is biotite felsic?
To be more specific, felsic rocks typically have biotite and/or amphibole; intermediate rocks have amphibole and, in some cases, pyroxene; and mafic rocks have pyroxene and, in some cases, olivine.
Where are felsic rocks formed?
The felsic magma is differentiated from mafic materials within the crust because of their varying densities and because mafic magma crystallizes first. Felsic rocks are mostly found within and on Earth’s continental crust because of the lighter and less dense elements and minerals that compose them.
Is felsic light or dark?
Felsic minerals are usually light in color and have specific gravities less than 3.0. Common felsic minerals include quartz, muscovite mica, and the orthoclase feldspars. The most common felsic rock is granite, which represents the purified end product of the earth’s internal differentiation process.
What rocks are created from felsic lava and magma?
Felsic magma is viscous and does not flow easily. Most felsic magma will stay deeper in the crust and will cool to form igneous intrusive rocks such as granite and granodiorite.
How is felsic formed?
For example, a coarse-grained, felsic igneous rock is not only a granite, it is an intrusive igneous rock that formed from slow cooling and crystallization of a body of magma within the earth’s crust. The intrusion of large bodies of granite – batholiths – is usually part of the origin of a mountain range.
What is the meaning of felsic?
Definition of felsic
: consisting of or chiefly consisting of feldspar or feldspathoid quartz.
Is obsidian a felsic rock?
Though obsidian is usually dark in color, similar to mafic rocks such as basalt, the composition of obsidian is extremely felsic. Obsidian consists mainly of SiO2 (silicon dioxide), usually 70% by weight or more. Crystalline rocks with a similar composition include granite and rhyolite.
Is pumice rock mafic or felsic?
Scoria is a mafic volcanic glass. It is an extremely vesicular basaltic lava with very small (
