Andesite most commonly denotes fine-grained, usually porphyritic rocks; in composition these correspond roughly to the intrusive igneous rock diorite and consist essentially of andesine (a plagioclase feldspar) and one or more ferromagnesian minerals, such as pyroxene or biotite.

Do andesite and basalt have the same composition?

Andesite is the name of a family of fine-grained, extrusive igneous rocks that are usually light to dark gray in color. They have a mineral composition that is intermediate between granite and basalt.

Do andesite and diorite have the same composition?

Diorite and andesite are similar rocks. They have the same mineral composition and occur in the same geographic areas. ... Andesite forms when a similar magma crystallizes quickly at Earth's surface. That rapid cooling produces a rock with small crystals.

Which rock has the same composition but a different texture than andesite?

Igneous rocks are categorized in pairs. The two rocks in a pair have the same composition but different textures: gabbro-basalt, diorite-andesite, and granite-rhyolite.

What kind of igneous rock is andesite?

Andesite is a fine-grained, extrusive igneous or volcanic rock. It is dark grey and made up of equal amounts of light and dark minerals, although the crystals are too small to be seen without a magnifier. Occasionally andesite may contain some larger crystals.

Geology: Andesite vs Diorite

38 related questions found

What is the composition of andesite?

Andesite most commonly denotes fine-grained, usually porphyritic rocks; in composition these correspond roughly to the intrusive igneous rock diorite and consist essentially of andesine (a plagioclase feldspar) and one or more ferromagnesian minerals, such as pyroxene or biotite. ...

What is the chemical composition of andesite?

Chemical Composition of Andesite

Andesite is an intermediate sub-alkalic rock with SiO2 contents ranging between 57 and 63 wt. %, and Na2O + K2O contents around 5 wt. %. Intermediate rocks are also characterized by an increased CaO content compared to that in acidic rocks.

Which of the following igneous rocks has the same chemical composition as basalt?

Gabbro. Gabbro is a silica-poor intrusive igneous (plutonic) rock chemically equivalent to basalt. It is normally coarse-grained, dark and typically contains feldspar, augite and sometimes olivine.

What volcanic rock has the same general chemical composition as granite?

Volcanic rock of equivalent chemical composition and mineralogy is called rhyolite. Granites are the most abundant plutonic rocks of mountain belts and continental shield areas.

Is quartz an Aphanitic?

Aphanites are commonly porphyritic, having large crystals embedded in the fine groundmass, or matrix. ... They consist essentially of very small crystals of minerals such as plagioclase feldspar, with hornblende or augite, and may contain also biotite, quartz, and orthoclase.

What is the difference between basalt and andesite?

Both lavas are formed at different plate boundaries which is why they have different silica contents: the basaltic lava forms from the hot mantle material at constructive plate boundaries and hotspots whereas the andesitic lava forms at destructive plate boundaries from melting crust.

How would you distinguish andesite from a diorite?

How would you distinguish Andesite from a Diorite? Based on grain size. Andesite is a fine grained (intermediate) rock, while Diorite is a coarse grained rock.

Is Obsidian a Phaneritic?

The result is a natural amorphous glass with few or no crystals. Examples include obsidian. ... The minerals in a phaneritic igneous rock are sufficiently large to see each individual crystal with the naked eye. Examples of phaneritic igneous rocks are gabbro, diorite and granite.

How common is andesite?

Andesite is the most common volcanic rock after basalt . It is porphyritic, that is, consists of coarse crystals (phenocrysts) embedded in a granular or glassy matrix (groundmass). Having a silica content of 57%, it is in the intermediate category (52–66% silica) of the silicic–mafic scale.

What is the similarities of mafic and intermediate?

Mafic rocks are dominated by plagioclase and pyroxene (even if you can't see them with the naked eye) and smaller amounts of olivine. Intermediate rocks are roughly even mixtures of felsic minerals (mainly plagioclase) and mafic minerals (mainly hornblende, pyroxene, and/or biotite). There is little or no quartz.

Do granite and rhyolite have the same composition?

A rhyolite is this and is usually erupted onto Earth's surface. ... The difference is that granite sits on the plutonic diagram and rhyolite sits on the volcanic diagram. So they have a similar composition but one is volcanic and the other is plutonic.

Can the same volcano produce volcanic rocks with different compositions?

Volcanoes produce different types of volcanic rocks. The creation of volcanic rocks depends on the type of eruption and the source and composition of the magma erupted. ... For example, basalt (a dark gray to black rock) contains more minerals of olivine and hornblende than andesite (a gray rock).

How are granite and rhyolite the same and how do they differ?

The difference between them is that rhyolite is an intrusive igneous rock whereas granite is an extrusive igneous rock. ... Rhyolite and Granite are the most common types of acidic rock. They have similar compositions. Granite is formed when magma cools down deep inside the earth crust.

What kinds of igneous rocks have the same mineral composition?

Granite and rhyolite have the same mineral composition, but their grain size gives each a distinct appearance. The key difference between intrusive and extrusive igneous rocks—the size of crystals making them up—is related to how rapidly melted rock cools.

Is andesite extrusive or intrusive?

Igneous Rock Types and Textures. Porphyritic texture -- andesite: This is an extrusive igneous rock. The magma from which it formed cooled slowly for a while deep below the surface (forming the large crystals), then finished cooling very quickly when it was ejected at the surface, forming the fine-grained groundmass.

What is the coarse grained rock with the same chemical composition as basalt?

Gabbro is a silica-poor intrusive igneous (plutonic) rock chemically equivalent to basalt. It is normally coarse-grained, dark and typically contains feldspar, augite and sometimes olivine.

What is peridotite chemical composition called?

doʊˌtaɪt, pəˈrɪd. ə-/ PERR-ih-doh-tyte, pə-RID-ə-) is a dense, coarse-grained igneous rock consisting mostly of the silicate minerals olivine and pyroxene. Peridotite is ultramafic, as the rock contains less than 45% silica.

What is the common use of andesite?

It is fairly strong, which allows it to be used in road and railway construction, and as fill gravel. The grayish colored rocks seen between railway ties are often andesite or its close relative, basalt. Perhaps the most interesting use of andesite is as proof of volcanic activity on Mars.

Where is andesite formed?

Andesite is typically formed at convergent plate margins but may also occur in other tectonic settings. Magmatism in island arc regions comes from the interplay of the subducting plate and the mantle wedge, the wedge-shaped region between the subducting and overriding plates.