Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are composed of usually greater than 90% mafic minerals (dark colored, high magnesium and iron content). The Earth's mantle is composed of ultramafic rocks. Ultrabasic is a more inclusive term that includes igneous rocks with low silica content that may not be extremely enriched in Fe and Mg, such as carbonatites and ultrapotassic igneous rocks.
Intrusive ultramafic rocks are often found in large, layered ultramafic intrusions where differentiated rock types often occur in layers. Such cumulate rock types...
Rare porphyritic volcanic rock Boninite – Ultramafic extrusive rock high in both magnesium and silica Carbonatite – Igneous rock with more than 50% carbonate...
The rock must then be classified chemically. Mineralogical classification of an intrusive rock begins by determining if the rock is ultramafic, a carbonatite...
Formation in Wyoming and, the following year, as inclusions in the ultramaficrock kimberlite from a diamond mine in Yakutia in the Russian Far East....
ferromagnesian minerals, such as olivine and pyroxene, in mafic and ultramaficrock to produce serpentinite. Minerals formed by serpentinization include...
Serpentine soil is an uncommon soil type produced by weathered ultramaficrock such as peridotite and its metamorphic derivatives such as serpentinite...
metamorphic rock composed predominantly of one or more serpentine group minerals formed by near to complete serpentinization of mafic to ultramafic rocks....
mafic mineral content. A rock with over 90% mafic mineral content will be classified instead as an ultramaficrock. A gabbroic rock with less than 10% mafic...
alkali oxides (K2O plus Na2O). These place the rock in one of the fields of the TAS diagram. Ultramaficrock and carbonatites have their own specialized...
feldspathoid. Special classifications exist for igneous rock of unusual compositions, such as ultramaficrock or carbonatites. Where possible, extrusive igneous...
be confused with the mineral olivenite), is an intrusive igneous rock of ultramafic composition and with phaneritic (coarse-grained) texture. The mineral...
Ni-Cu-PGE deposits can occur within the country rock spatially associated with the layered intrusion. Mafic-ultramafic layered intrusions occur at all levels within...
enhanced weathering technique is in-situ carbonation of silicates. Ultramaficrock, for example, has the potential to store from hundreds to thousands...
coarse-grained igneous rock consisting mostly of the silicate minerals olivine and pyroxene. Peridotite is ultramafic, as the rock contains less than 45%...
Wehrlite is an ultramafic and ultrabasic rock that is a mixture of olivine and clinopyroxene. It is a subdivision of the peridotites. The nomenclature...
breccias grade into root zones of dikes made of unfragmented rock. At the surface, ultramafic tuffs may occur in maar deposits. Because kimberlites are the...
sedimentary rock is termed its provenance. Magmatic protoliths can be further divided into three categories: ultramaficrock, mafic rock, and quartzo-feldspathic...
Talc carbonates are a suite of rock and mineral compositions found in metamorphosed ultramafic rocks. The term refers to the two most common end-member...
and polished serpentine ornaments are sold in local gift shops. This ultramaficrock also forms a very infertile soil which covers the flat and marshy heaths...
orthopyroxene, which are the most common mafic minerals in intrusive rock. Rare ultramafic rocks, which contain more than 90% mafic minerals, and carbonatite...
calcium hydroxide (Ca+2 + 2OH−) produced during serpentinization of ultramaficrock. When this alkaline water reaches the surface, it absorbs carbon dioxide...
; Luetkemeyer, P. Benjamin (2016-04-01). "Carbonatite associated with ultramafic diatremes in the Avon Volcanic District, Missouri, USA: Field, petrographic...
Greenstone belts are zones of variably metamorphosed mafic to ultramafic volcanic sequences with associated sedimentary rocks that occur within Archaean...
they are to other Araucaria. Much of New Caledonia is composed of ultramaficrock with serpentine soils, with low levels of nutrients, but high levels...
Ophiolites are sequences of mafic to ultramaficrock generally believed to represent ancient oceanic lithosphere. They are distributed all across the...
Piper diagram, used in hydrochemistry UIGS Classification diagram for Ultramaficrock USDA Soil texture diagram by particle sizes Apparent molar property...
(French: maquis minier) is a type of shrubland biome. It forms on ultramaficrock as a result of forest cover retreat due to repeated wildfires. It is...
of igneous rocks, represented by the Taitao ophiolites, which is an ultramaficrock composed of olivine and pyroxene, usually found in oceanic plates....
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