ultramafic rock

Ultramafic rock — Ultramafic (also referred to as ultrabasic) rocks are igneous and meta igneous rocks with 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… …   Wikipedia

ultramafic rock — /ʌltrəˌmæfɪk ˈrɒk/ (say ultruh.mafik rok) noun → ultrabasic rock …   Australian English dictionary

Ultramafic to mafic layered intrusions — are found in typically ancient cratons and are rare but worldwide in distribution. The intrusive complexes exhibit evidence of fractional crystallization and crystal segregation by settling or floating of minerals from a melt. Ideally the… …   Wikipedia

Rock microstructure — includes the texture of a rock and the small scale rock structures. The words texture and microstructure are interchangeable, with the latter preferred in modern geological literature. However, texture is still acceptable because it is a useful… …   Wikipedia

Igneous rock — Geologic provinces of the world (USGS)   Shield …   Wikipedia

igneous rock — Any of various crystalline or glassy, noncrystalline rocks formed by the cooling and solidification of molten earth material (magma). Igneous rocks comprise one of the three principal classes of rocks, the others being metamorphic and sedimentary …   Universalium

Cumulate rock — Cumulate rocks are igneous rocks formed by the accumulation of crystals from a magma either by settling or floating. Cumulate rocks are named according to their texture; cumulate texture is diagnostic of the conditions of formation of this group… …   Wikipedia

metamorphic rock — Any of a class of rocks that result from the alteration of preexisting rocks in response to changing geological conditions, including variations in temperature, pressure, and mechanical stress. The preexisting rocks may be igneous, sedimentary,… …   Universalium

List of rock textures — This page is intended to be a list of rock textural and morphological terms. A * Adcumulate * Agglomeritic * Adamantine a type of lustre * Amygdaloidal * Anhedral * Antitaxial veins * Aphanitic * Aplitic; aplite * Augen textured gneiss *… …   Wikipedia

Common occurrences of rock-forming garnets — ▪ Table Common occurrences of rock forming garnets almandine metamorphic rocks especially mica schists, amphibolites, and granulites; granites, aplites, and granitic pegmatites spessartine granitic pegmatites; silica rich skarns; metamorphosed… …   Universalium

Roca ultrabásica — Saltar a navegación, búsqueda Las rocas ultrabásicas (también referida como ultramáficas) son rocas ígneas y meta ígneas con muy bajo sílice (menos de 45%), generalmente >18% MgO, alto FeO, bajo potasio, y se compone de usualmente más de 90%… …   Wikipedia Español