Is porphyritic granite intrusive or extrusive?
Intrusive
Porphyritic Granite
| Type | Igneous Rock |
|---|---|
| Texture | Porphyritic |
| Origin | Intrusive/Plutonic |
| Chemical Composition | Felsic |
| Color | Predominately white |
Is porphyritic intrusive and extrusive?
Porphyritic is an adjective used in geology to describe igneous rocks with a distinct difference in the size of mineral crystals, with the larger crystals known as phenocrysts. Both extrusive and intrusive rocks can be porphyritic, meaning all types of igneous rocks can display some degree of porphyritic texture.
What type of rock is porphyritic andesite?
Igneous Rock
Porphyritic Andesite
| Type | Igneous Rock |
|---|---|
| Origin | Extrusive/Volcanic |
| Chemical Composition | Intermediate |
| Color | Dark Green |
| Mineral Composition | Sodium – Calcium Plagioclase, Pyroxene, Hornblende |
Is andesite an intrusive igneous rock?
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 a porphyritic granite?
In terms of its mineral content this is a typical granite, consisting of pink potassium feldspar, cream sodium feldspar (plagioclase), grey quartz and black biotite mica. The most striking feature of its texture is the large pink angular potassium feldspar crystals (one of which is indicated by the yellow pointer).
Is porphyritic rhyolite intrusive or extrusive?
Extrusive
Porphyritic Rhyolite
| Type | Igneous Rock |
|---|---|
| Texture | Porphyritic |
| Origin | Extrusive/Volcanic |
| Chemical Composition | Felsic |
| Color | Light Green |
Is andesite intrusive or extrusive?
extrusive igneous rock
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.
Is andesite extrusive or intrusive?
Is granite an igneous?
granite, coarse- or medium-grained intrusive igneous rock that is rich in quartz and feldspar; it is the most common plutonic rock of the Earth’s crust, forming by the cooling of magma (silicate melt) at depth.
Can granite be porphyritic?
Porphyritic texture is quite common in granites, as well as in lavas erupted from volcanoes.
What type of rock is granite?
Granite is an igneous rock that forms when magma cools relatively slowly underground. It is usually composed primarily of the minerals quartz, feldspar, and mica. When granite is subjected to intense heat and pressure, it changes into a metamorphic rock called gneiss.
What is porphyritic andesite?
What is porphyritic andesite? Andesite ( /ˈænd?sa?t/ or /ˈænd?za?t/) is an extrusive igneous volcanic rock of intermediate composition, with aphanitic to porphyritic texture. Characteristic of subduction zones, andesite represents the dominant rock type in island arcs.
Andesite is a fine-grained, extrusive igneous rock composed mainly of plagioclase with other minerals such as hornblende, pyroxene, and biotite. Click to see full answer. Correspondingly, how do you tell if a rock is intrusive or extrusive?
What is the difference between granite and peridotite?
Granite is a coarse-grained, light-colored, intrusive igneous rock that contains mainly quartz, feldspar, and mica minerals. The specimen above is about two inches (five centimeters) across. Peridotite is a coarse-grained intrusive igneous rock that is composed almost entirely of olivine.
Is granite extrusive or intrusive?
The way Granite is formed, and the elements it is composed of is what makes it an intrusive rock and not an extrusive one. The formation of different types of Granite is one of the most interesting natural occurrences taking place underneath the surface.