Ultramafic rock

ultramaficultrabasicultramafic rocksultramafic soilultrabasic rockultramaficsultra-maficultrabasic rocksultra mafic unitsultramafic bedrock
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).wikipedia
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Ultrapotassic igneous rocks

ultrapotassicultrapotassic intrusive 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.
Ultrapotassic igneous rocks are a class of rare, volumetrically minor and generally ultramafic or mafic silica-depleted igneous rocks.

Pyroxenite

clinopyroxenitepyroxeniticorthopyroxenite
The ultramafic intrusives include the dunites, peridotites and pyroxenites.
Pyroxenite is an ultramafic igneous rock consisting essentially of minerals of the pyroxene group, such as augite, diopside, hypersthene, bronzite or enstatite.

Peridotite

peridotitesperidotiticgarnet peridotite
The ultramafic intrusives include the dunites, peridotites and pyroxenites.
Peridotite is ultramafic, as the rock contains less than 45% silica.

Dunite

olivinite bombs
The ultramafic intrusives include the dunites, peridotites and pyroxenites.
Dunite ( or ) (also known as olivinite, not to be confused with the mineral olivenite) is an igneous, plutonic rock, of ultramafic composition, with coarse-grained or phaneritic texture.

Komatiite

komatiiteskomatiitic
Examples include komatiite and picritic basalt.
Komatiite is a type of ultramafic mantle-derived volcanic rock defined as having crystallised from a lava with ≥ 18 wt% MgO.

Nickel

NiNi 2+ Nickel (Ni)
Komatiites can be host to ore deposits of nickel.
Even so, pure native nickel is found in Earth's crust only in tiny amounts, usually in ultramafic rocks, and in the interiors of larger nickel–iron meteorites that were not exposed to oxygen when outside Earth's atmosphere.

Igneous rock

igneousigneous rocksdecompression melting
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).

Anorthosite

anorthositic
These grade into the anorthosites.
Importantly, large volumes of ultramafic rocks are not found in association with Proterozoic anorthosites.

Norite

gabbronoriteGombak noritenoritic
Gabbro and norite often occur in the upper portions of the layered ultramafic sequences.
Norite occurs with gabbro and other mafic to ultramafic rocks in layered intrusions which are often associated with platinum orebodies such as in the Bushveld Igneous Complex in South Africa, the Skaergaard igneous complex of Greenland, and the Stillwater igneous complex in Montana.

Lamprophyre

kersantitemonchiquitelamprophyres
Ultrapotassic, ultramafic igneous rocks such as lamprophyre, lamproite and kimberlite are known to have reached the surface of the Earth.
They are alkaline silica-undersaturated mafic or ultramafic rocks with high magnesium oxide, >3% potassium oxide, high sodium oxide and high nickel and chromium.

Volcano

volcanicvolcanoesvolcanic igneous activity
Volcanic ultramafic rocks are rare outside of the Archaean and are essentially restricted to the Neoproterozoic or earlier, although some boninite lavas currently erupted within back-arc basins (Manus Trough, New Guinea) verge on being ultramafic.

Phlogopite

fluorphlogopite micatetraferriphlogopite
Hornblendite and, rarely phlogopite, are also found.
Several igneous associations are noted: high-alumina basalts, ultrapotassic igneous rocks, and ultramafic rocks.

Olivine

olivine basaltchrysoliteolivine group
It has a characteristic abundance of olivine or serpentine and a scarcity or absence of feldspar and quartz.
Olivine occurs in both mafic and ultramafic igneous rocks and as a primary mineral in certain metamorphic rocks.

Hornblendite

Horneblende dolerite
Hornblendite and, rarely phlogopite, are also found.
Hornblende-rich ultramafic rocks are rare and when hornblende is the dominant mineral phase they are classified as hornblendites with qualifiers such as garnet hornblendite identifying a second abundant contained mineral.

Talc carbonate

talc-carbonation
Metamorphism of ultramafic rocks in the presence of water and/or carbon dioxide results in two main classes of metamorphic ultramafic rock; talc carbonate and serpentinite.
Talc carbonates are a suite of rock and mineral compositions found in metamorphosed ultramafic rocks.

Serpentinite

serpentineserpentinizationserpentinized
Metamorphism of ultramafic rocks in the presence of water and/or carbon dioxide results in two main classes of metamorphic ultramafic rock; talc carbonate and serpentinite.
Minerals in this group, which are rich in magnesium and water, light to dark green, greasy looking and slippery feeling, are formed by serpentinization, a hydration and metamorphic transformation of ultramafic rock from the Earth's mantle.

Serpentine subgroup

serpentineantigoriteserpentine group
It has a characteristic abundance of olivine or serpentine and a scarcity or absence of feldspar and quartz.
The serpentine group describes a group of common rock-forming hydrous magnesium iron phyllosilicate ( 3 ) minerals, resulting from the metamorphism of the minerals that are contained in ultramafic rocks.

Serpentine soil

serpentineserpentine soilsserpentine barrens
Serpentine soil is a magnesium rich, calcium, potassium and phosphorus poor soil that develops on the regolith derived from ultramafic rocks.
Serpentine soil is an uncommon soil type produced by weathered ultramafic rock such as peridotite and its metamorphic derivatives such as serpentinite.

Kimberlite

kimberlite pipeskimberlitickimberlites
Ultrapotassic, ultramafic igneous rocks such as lamprophyre, lamproite and kimberlite are known to have reached the surface of the Earth. Rare occurrences may include unusual surface deposits of maars of kimberlites in the diamond fields of southern Africa and other regions.
Group-I kimberlites are of CO 2 -rich ultramafic potassic igneous rocks dominated by primary forsteritic olivine and carbonate minerals, with a trace-mineral assemblage of magnesian ilmenite, chromium pyrope, almandine-pyrope, chromium diopside (in some cases subcalcic), phlogopite, enstatite and of Ti-poor chromite.

Cumulate rock

cumulatecumulatesCumulate rocks
Such cumulate rock types do not represent the chemistry of the magma from which they crystallized.

Lateritic nickel ore deposits

nickel lateritenickel laterite orelaterite nickel ore
Weathered ultramafic rocks may form lateritic nickel ore deposits.
Lateritic nickel ore deposits are surficial, weathered rinds formed on ultramafic rocks.

Magnesite

magnasite
Often thick, magnesite-calcrete caprock, laterite and duricrust forms over ultramafic rocks in tropical and subtropical environments.
Magnesite occurs as veins in and an alteration product of ultramafic rocks, serpentinite and other magnesium rich rock types in both contact and regional metamorphic terrains.

New Caledonia rain forests

coastal forestrain forestrainforest
Examples are the ultramafic woodlands and barrens of the Appalachian mountains and piedmont, the "wet maquis" of the New Caledonia rain forests, and the ultramafic forests of Mount Kinabalu and other peaks in Sabah, Malaysia.
The islands soils derived largely from ultramafic rocks, and have been a refuge for many native flora species that have adapted to their composition a long time ago; such flora can survive on acid soils with unfavourable compositions of nutrient elements.

Mount Kinabalu

Gunung KinabaluKinabaluKinabalu montane alpine meadows
Examples are the ultramafic woodlands and barrens of the Appalachian mountains and piedmont, the "wet maquis" of the New Caledonia rain forests, and the ultramafic forests of Mount Kinabalu and other peaks in Sabah, Malaysia.
However, most of Kinabalu's endemic species are found in the mountain forests, particularly on ultramafic soils (i.e. soils which are low in phosphates and high in iron and metals poisonous to many plants; this high toxic content gave rise to the development of distinctive plant species found nowhere else).

Layered intrusion

ultramafic intrusionslayered igneous intrusionlayered mafic intrusion
Intrusive ultramafic rocks are often found in large, layered ultramafic intrusions where differentiated rock types often occur in layers.
Although most are ultramafic to mafic in composition, the Ilimaussaq intrusive complex of Greenland is an alkalic intrusion.