What is the composition of peridotite?
peridotite, a coarse-grained, dark-coloured, heavy, intrusive igneous rock that contains at least 10 percent olivine, other iron- and magnesia-rich minerals (generally pyroxenes), and not more than 10 percent feldspar.
What does composition mean in rocks?
Composition refers to both the types of minerals within a rock and the overall chemical makeup of the rock (the two are obviously related). Texture refers to the size and arrangement of the minerals or grains that make up a rock. Igneous Rock Textures.
How do peridotite and dunite differ from each other in mineral composition?
Peridotite is a very dense, coarse-grained, olivine-rich, ultra- mafic intrusive rock. Mineral content – generally olivine with lesser pyroxene ( augite) (dunite is dominantly olivine), always contains some metallic minerals, e.g. chromite, magnetite.
What is dunite composed of?
dunite, light yellowish green, intrusive igneous ultramafic rock that is composed almost entirely of olivine. It is a common rock in Earth’s upper mantle.
What is peridotite quizlet?
peridotite. A coarse-grained ultramafic intrusive igneous rock composed of olivine with small amounts of pyroxene and amphibole. The dominant rock in Earth’s mantle and the source rock of basaltic melts.
What is the main composition of rock?
Rocks are composed primarily of grains of minerals, which are crystalline solids formed from atoms chemical bonded into an orderly structure. Some rocks also contain mineraloids, which are rigid, mineral-like substances, such as volcanic glass, that lacks crystalline structure.
What is the composition of igneous rock?
Because of the dominance of oxygen and silicon in the crust, igneous rocks are mostly made up of silicate minerals. These silicates can be generally divided into light and dark silicates. The dark silicates are also called ferromagnesian because of the presence of iron and magnesium in them.
What is the importance of peridotite?
Peridotites are economically important rocks because they often contain chromite – the only ore of chromium; they can be source rocks for diamonds; and, they have the potential to be used as a material for sequestering carbon dioxide. Much of Earth’s mantle is believed to be composed of peridotite.
Why is peridotite considered the densest among igneous rocks?
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. It is high in magnesium (Mg2+), reflecting the high proportions of magnesium-rich olivine, with appreciable iron.
Are dunite and peridotite the same?
Dunite is the olivine-rich endmember of the peridotite group of mantle-derived rocks. Dunite and other peridotite rocks are considered the major constituents of the Earth’s mantle above a depth of about 400 km (250 mi).
What is the meaning of dunite?
: a granular igneous rock consisting chiefly of olivine.
What kind of minerals are found in peridotite?
Other notable minerals that are often present are chromite, garnet, and plagioclase. It is an ultramafic rock (mafic minerals make up more than 90% of the rocks composition). Peridotite is often massive (homogeneous) just like other plutonic rocks, but it can be also layered.
What’s the difference between a peridotite and a plutonic rock?
It is an ultramafic rock (mafic minerals make up more than 90% of the rocks composition). Peridotite is often massive (homogeneous) just like other plutonic rocks, but it can be also layered. Layered peridotite is a cumulate rock formed by crystal settling from magma. Layered ultramafic typically occur at the base of gabbroic intrusions.
How are peridotites used in the scientific world?
– Peridotites are rocks that originate in the Earth’s mantle and from there emerge to the surface through magmas. Researchers believe that the mantle is composed primarily of these types of rocks. – As a store or reservoir of carbon dioxide, peridotite rocks can be used for scientific purposes.
Why are peridotite rocks used in Diamond veins?
Peridotites are rocks of great value in the market because they usually contain chromite, the only chromium mineral. Likewise, they are found in diamond veins, since they can contain them as source rock. They can also be used as a primary material to take up carbon dioxide.
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