What does dunite look like?
What does dunite look like?
Dunite, light yellowish green, intrusive igneous ultramafic rock that is composed almost entirely of olivine. Chromite, picotite, and magnetite also occur in dunite, as do spinel, ilmenite, pyrrhotite, and platinum in some cases. Dunites constitute an important source of chromium, a commercially valuable metal.
Are dunite and peridotite the same?
Dunite is the olivine-rich end-member 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 kilometers.
What is dunite used for?
Peridotite Uses As a source of valuable ores and minerals, including chromite, platinum, nickel and precious garnet; diamonds are obtained from mica-rich peridotite (kimberlite) in South Africa.
What makes dunite different from other igneous rocks?
Dunite is an ultramafic plutonic rock that is composed almost exclusively of olivine. “Ultramafic” means that mafic minerals form more than 90% on the rocks composition. ‘Plutonic’ means that the rock is not volcanic, it didn’t form at or near the surface.
How is dunite extracted?
Dunite forms either as a cumulate within layered intrusions or as a residue after extraction of partial melt from a pre-existing ultrabasic rock in the mantle. It is also found in alpine peridotite massifs that represent slivers of sub-continental mantle exposed during collisional orogeny.
What is the color of peridotite?
Peridotite
| Type | Igneous Rock |
|---|---|
| Origin | Intrusive/Plutonic |
| Chemical Composition | Ultramafic |
| Color | Medium Green |
| Mineral Composition | Olivine |
Is dunite metamorphic?
Dunite is an igneous plutonic rock of ultramafic composition with coarse-grained granular or phaneritic texture and often massive or layered.
What percent of dunite is silica?
Texture – phaneritic (coarse grained). Mineral content – generally olivine with lesser pyroxene ( augite) (dunite is dominantly olivine), always contains some metallic minerals, e.g. chromite, magnetite. Silica (SiO 2) content – < 45%.
Is dunite plutonic?
Is Dunite metamorphic?
Does Dunite contain quartz?
Peridotite is a generic name used for coarse-grained, dark-colored, ultramafic igneous rocks. Their silica content is low compared to other igneous rocks, and they contain very little quartz and feldspar.
What kind of rock is a dunite made of?
Dunite is an ultramafic plutonic rock that is composed almost exclusively of olivine.
Why does dunite have a dull yellow color?
Dunite is mostly composed of olivine which is a bright green mineral. Fresh rock is green as well. However, olivine readily alters and loses its bright green color pretty quickly. Chances are very high that on the way up in the crust olivine grains lost some of its brightness. Hence, many samples look dull yellow, not green anymore.
Where did the name dunite mountain come from?
Dunite was named by the German geologist Ferdinand von Hochstetter in 1859, after Dun Mountain near Nelson, New Zealand.
Where can you find Cumulate dunite in the world?
Cumulate dunite may also be found in ophiolite complexes, associated with layers of wehrlite, pyroxenite, and gabbro. Dunite was named by the German geologist Ferdinand von Hochstetter in 1859, after Dun Mountain near Nelson, New Zealand.