Table of Contents
What ores are associated with diamonds?
The dominant source rocks for diamond are highly depleted peridotite (harzburgite or dunite) and high-pressure eclogite. These are minor components of the mantle lithosphere, which is dominated by less-depleted peridotite (primarily lherzolite) and lesser amounts of non-diamondiferous eclogite.
What minerals contain diamonds?
diamond, a mineral composed of pure carbon. It is the hardest naturally occurring substance known; it is also the most popular gemstone. Because of their extreme hardness, diamonds have a number of important industrial applications.
How are eclogites formed?
Eclogites consist primarily of green pyroxene (omphacite) and red garnet (pyrope), with small amounts of various other stable minerals—e.g., rutile. They are formed when volcanic or metamorphic rocks rich in such mafic minerals are subjected to extremely high pressures and moderate to relatively high temperatures.
How does basalt become eclogite?
Eclogites form when mafic rock (basalt or gabbro) descends deep within the Earth, generally at a subduction zone.
What mineral class is diamond in?
DiamondDiamond / Mineral class
What type of rock is a dolostone?
Dolostone is a fine-grained sedimentary rock composed primarily of dolomite, a calcium and magnesium carbonate mineral. Dolostone is similar to limestone and is in some cases formed secondarily from chemically-altered limestone.
Is Trachyte a mineral or a rock?
trachyte, light-coloured, very fine-grained extrusive igneous rock that is composed chiefly of alkali feldspar with minor amounts of dark-coloured minerals such as biotite, amphibole, or pyroxene. Compositionally, trachyte is the volcanic equivalent of the plutonic (intrusive) rock syenite.
Is eclogite a mineral a rock or neither?
Eclogite: A high P/T metamorphic rock composed of more than 75% vol. garnet (often pyrope or Mg-rich almandine) and omphacite (Na-Ca-Al-Mg clinopyroxene). Both must be present and neither component more than 75% vol.
What are group a eclogite xenoliths?
Group A eclogite xenoliths remain the most enigmatic in terms of their origin due to metasomatic overprinting of their original composition.
What are the characteristics of Group C eclogites?
Group A eclogites frequently contain quartz, kyanite, and zoisite. Kyanite seems to be absent in group C eclogites and quartz is rare. Group C eclogites bear amphiboles, epidote, and rutile 5. Eclogite may be more fine-grained and darker in appearance. This sample from Norway is mostly composed of amphacite + garnet.
Does eclogite melt in the mantle?
Partial melting of eclogite has been modeled to produce tonalite-trondhjemite-granodiorite melts. Eclogite-derived melts may be common in the mantle, and contribute to volcanic regions where unusually large volumes of magma are erupted.
Where are coesite and glaucophane eclogites found?
Coesite- and glaucophane-bearing eclogites have been found in the northwestern Himalaya. The oldest coesite-bearing eclogites are about 650 and 620 million years old and they are located in Brazil and Mali, respectively. ^ Zheng, Yong-Fei; Chen, Ren-Xu (September 2017).