What kind of rock is a pyroxenite?

What kind of rock is a pyroxenite?

Pyroxenites are ultramafic intrusive igneous rocks composed almost entirely of dark Pyroxene group minerals rich in iron and magnesium, e.g., Augite, Diopside, Hypersthene, Diallage, Bronzite, and Enstatite, unlike other mafic minerals Olivine and Amphibole.

What type of igneous rock is andesite?

extrusive igneous
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.

Is pyroxenite felsic or mafic?

Pyroxenite is an ultramafic plutonic igneous rock. Ultramafic means that more than 90% of the rock is composed of magnesium- and iron-rich minerals like pyroxenes, amphiboles, and olivine. In pyroxenite the dominant mafic mineral is a pyroxene.

Is basalt an intrusive igneous rock?

Intrusive igneous rocks crystallize below Earth’s surface, and the slow cooling that occurs there allows large crystals to form. These rocks include: andesite, basalt, dacite, obsidian, pumice, rhyolite, scoria, and tuff. Pictures and brief descriptions of some common igneous rock types are shown on this page.

Is pyroxenite magnetic?

Olivine dominates the magnetic fabric of the peridotite samples. The pyroxenite samples display a complex relationship between the measured and modelled AMS, which is related to the competing magnetic fabrics of clinopyroxene, orthopyroxene and hornblende.

Is andesite a real 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 kind of rock is a pyroxene meteorite?

A sample of the orthopyroxenite meteorite ALH84001. Pyroxenite is an ultramafic igneous rock consisting essentially of minerals of the pyroxene group, such as augite, diopside, hypersthene, bronzite or enstatite.

What makes a rock an intrusive or extrusive rock?

Notice the large grains of pink, white, and gray minerals. If the magma forces its way to the surface, it is then called lava, which cools and hardens into extrusive rocks. The lava cools much faster on the surface, so the minerals either form crystals that are too small to see easily, or else it forms a volcanic glass with no crystals at all.

How are pyroxenites formed in an ultramafic intrusion?

Pyroxenites can be formed as cumulates in ultramafic intrusions by accumulation of pyroxene crystals at the base of the magma chamber. Here they are generally associated with gabbro and anorthite cumulate layers and are typically high up in the intrusion.

How are Igneous pyroxenites different from gabbros and norites?

Igneous pyroxenites are closely allied to gabbros and norites, from which they differ by the absence of feldspar, and to peridotites, which are distinguished from them by containing more than 40% olivine.