Is Trachyte felsic or mafic?

Is Trachyte felsic or mafic?

Trachyte (/ˈtreɪˌkaɪt, ˈtrækˌaɪt/) is an extrusive igneous rock composed mostly of alkali feldspar. It is usually light-colored and aphanitic (fine-grained), with minor amounts of mafic minerals, and is formed by the rapid cooling of lava enriched with silica and alkali metals.

What type of rock is Trachyte porphyry?

extrusive igneous rock
Trachyte is a extrusive igneous rock that light coloured is composed mostly of alkali feldspar with minor amount of dark coloured minerals such as biotite, amphibole, or pyroxene. Trachyte is the volcanic equivalent of rock Syenite.

Is andesite porphyry mafic or felsic?

Andesite is INTERMEDIATE in composition between MAFIC and FELSIC rocks. The mixture of mafic and felsic minerals gives the rock a “salt and pepper” appearance. DIORITE – phaneritic rock (large crystals) of both mafic and felsic minerals.

How do you tell if a rock is felsic or mafic?

In a widely accepted silica-content classification scheme, rocks with more than 65 percent silica are called felsic; those with between 55 and 65 percent silica are intermediate; those with between 45 and 55 percent silica are mafic; and those with less than 45 percent are ultramafic.

What is the mineral composition of trachyte?

trachyte, light-coloured, very fine-grained extrusive igneous rock that is composed chiefly of alkali feldspar with minor amounts of dark-coloured minerals such as biotite, amphibole, or pyroxene. Compositionally, trachyte is the volcanic equivalent of the plutonic (intrusive) rock syenite.

Is trachyte intermediate?

Trachyte is an extrusive rock, belonging to the alkali series of intermediate volcanic rocks.

What type of rock is felsic?

In geology, felsic is an adjective describing igneous rocks that are relatively rich in elements that form feldspar and quartz. It is contrasted with mafic rocks, which are relatively richer in magnesium and iron.

Is Trachyte porphyry volcanic or plutonic?

Compositionally, trachyte is the volcanic equivalent of the plutonic (intrusive) rock syenite. Most trachytes show porphyritic texture in which abundant, large, well-formed crystals (phenocrysts) of early generation are embedded in a very fine-grained matrix (groundmass).

What kind of rock is a trachyte rock?

Trachyte is not necessarily volcanic in the strict sense. It may also form underground but still relatively close to the surface because its grain size is fine. Coarse-grained rocks with a trachytic composition are know as syenites as said before.

Which is a porphyritic rock and which is felsic?

Hence, rhyolite and basalt as fine-grained volcanic rocks are porphyritic and granite, syenite, etc. as coarse-grained plutonic rocks are porphyraceous. Phenocrysts that make up porphyry should be felsic (quartz, feldspar). Well, as you can see, mankind is very good when a need arises to make simple concepts difficult to understand.

Where is trachyte most likely to be found?

It is the volcanic equivalent of syenite. Trachyte is common wherever alkali magma is erupted, including in late stages of volcanism of ocean islands and in continental rift valleys and above mantle plumes. Trachyte has also been found in Gale crater on Mars.

How are trachyte and syenite similar to each other?

See TAS diagram below to see how these rock types differ in their chemistry. Trachyte is a volcanic equivalent of syenite. Syenite is a feldspar-rich plutonic rock which is similar to granite but lacks or contains very little quartz.