Press "Enter" to skip to content

How are intrusive igneous rocks formed?

Intrusive, or plutonic, igneous rock forms when magma is trapped deep inside the Earth. Intrusive rocks have a coarse grained texture. Extrusive Igneous Rocks: Extrusive, or volcanic, igneous rock is produced when magma exits and cools above (or very near) the Earth’s surface.

What are the two types of intrusive igneous rocks?

Examples of intrusive igneous rocks are: diabase, diorite, gabbro, granite, pegmatite, and peridotite. Extrusive igneous rocks erupt onto the surface, where they cool quickly to form small crystals.

What is an intrusive landform?

Volcanic landforms are divided into extrusive and intrusive landforms based on weather magma cools within the crust or above the crust. Intrusive landforms are formed when magma cools within the crust and the rocks are known as Plutonic rocks or intrusive igneous rocks.

Is diorite intrusive or extrusive?

Diorite, medium- to coarse-grained intrusive igneous rock that commonly is composed of about two-thirds plagioclase feldspar and one-third dark-coloured minerals, such as hornblende or biotite.

Where is diorite commonly found?

Diorite. Diorite is an intrusive rock intermediate in composition between gabbro and granite. It is produced in volcanic arcs, and in mountain building where it can occur in large volumes as batholiths in the roots of mountains (e.g. Scotland, Norway).

What is the origin of diorite?

Diorite formed deep within the Earth’s crust from cooling magma that never made it to the surface. It usually occurs as quite small intrusions often associated with larger intrusions like granite. Slow cooling produces the large crystals.

Does diorite have quartz?

Diorite ( /ˈdaɪ. əˌraɪt/) is an intrusive igneous rock composed principally of the silicate minerals plagioclase feldspar (typically andesine), biotite, hornblende, and/or pyroxene. Diorite may contain small amounts of quartz, microcline, and olivine.

What type of rock is quartz diorite?

Quartz diorite is an igneous, plutonic (intrusive) rock, of felsic composition, with phaneritic texture. Feldspar is present as plagioclase (typically oligoclase or andesine) with 10% or less potassium feldspar. Quartz is present at between 5 and 20% of the rock.

Does granite contain quartz?

Granite is a light-colored plutonic rock found throughout the continental crust, most commonly in mountainous areas. It consists of coarse grains of quartz (10-50%), potassium feldspar, and sodium feldspar. These minerals make up more than 80% of the rock.

What is the texture of a diorite rock?

Diorite is a plutonic igneous rock with intermediate composition between mafic and felsic rocks. It is visibly crystalline and usually has a granular texture (composed of roughly equally sized crystals) although the appearance may vary widely. Its volcanic (fine-grained) analogue is andesite.

What is the texture of gabbro rock?

Gabbro is mafic, intrusive, coarse-grained rock with allotriomorphic texture. Gabbros contain mainly ferromagnesian minerals and plagioclase, the amount of ferromagnesian minerals equaling or exceeding that of the plagioclase.