Ultramafic rock - Wikipedia
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 usually composed of greater than 90% mafic minerals (dark colored, high magnesium and iron content).
Ultramafic Rock - an overview | ScienceDirect Topics
Ultramafic rocks are usually defined by their modal mineralogy. They have a color index greater than 90, where the term “color index” refers to the percentage of mafic minerals such as olivine and pyroxene present in the rock. The term “ultrabasic” is applied to igneous rocks which contain < 45 wt% silica (SiO 2) in their bulk chemical composition.
Ultrabasic igneous rocks - SpringerLink
Ultrabasic is a general term, probably first used by J.W. Judd in 1881, applied to igneous rocks containing little or no feldspar and characterized essentially by the abundance of one or more common mafic minerals such as olivine, pyroxene, and amphibole. Chemically, the rocks contain <45% SiO 2 and the term ultrabasic is used along with basic ...
Ultramafic Rocks Examples and Composition | Geology Base
2023年12月12日 · Ultrapotassic rocks are silica-poor igneous rocks with a high potassium oxide to magnesium oxide ratio, usually more than 3. Examples include kimberlites, melilite rocks, lamprophyres, leucitites, etc. Those with less than 45% silica, more than 18% magnesium oxide, and more than 90% mafic minerals are ultramafic.
6.7.3: Ultramafic Igneous Rocks - Geosciences LibreTexts
2022年12月16日 · We call ultramafic rocks rich in olivine, peridotite. Those that are less than half olivine are pyroxenites. Other names, shown in the figure, divide peridotites and pyroxenites into smaller classes. Many specimens of ultramafic rock are carried up …
Ultramafic geoecosystems as a natural source of Ni, Cr, and Co to …
2021年2月10日 · Developed on rocks derived predominately from the Earth's mantle and metamorphosed at the ocean floors, ultramafic soils form in the places where tectonic forces brought these rocks from mantle depths to the surface.
Geology Dictionary - Ultrabasic, Ultramafic
Ultrabasic Rock. An igneous rock with a very low silica content and rich in minerals such as hypersthene, augite, and olivine. These rocks are also known as ultramafic rocks. Examples include: peridotite, kimberlite, lamprophyre, lamproite, dunite, and komatiite. Shown in the photo is a specimen of peridotite.
Ultramafic rock - New World Encyclopedia
Ultramafic (or ultrabasic) rocks are dark-colored igneous and meta-igneous rocks that are rich in minerals containing magnesium and iron ("mafic" minerals) and have a relatively low content of silica.
Deducing Mineralogy of Serpentinized and Carbonated Ultramafic …
2021年9月2日 · Serpentinization of ultramafic rocks is fundamental to modern plate tectonics and for volatile (re-)cycling into the mantle and magmatic arcs. Serpentinites are also highly reactive with CO 2 such that they are prime targets for carbon sequestration.
Geological setting, tectonic evolution and spatio-temporal ...
2023年3月15日 · The typical ultrabasic rock nickel (copper) deposit is the Ban Phuc copper-nickel deposit in Vietnam. Two types of chromite deposits are magmatic (ophiolite) one produced in ultrabasic rocks and the placer chromite one, mainly distributed in Song Ma, Indo-Burman Ranges, Putao-Myitkyina, east Philippine islands and other ultra-basic igneous rock ...