What type of rock is a eclogite?
metamorphic rocks
eclogite, any member of a small group of igneous and metamorphic rocks whose composition is similar to that of basalt. Eclogites consist primarily of green pyroxene (omphacite) and red garnet (pyrope), with small amounts of various other stable minerals—e.g., rutile.
What are diamond bearing rocks?
Diamond-bearing kimberlites are volcanic rocks that originate deep in the Earth and are erupted onto the surface. Researchers have now shown that other rock types, incorporated into the magma as it rises through overlying formations, provide the necessary buoyancy for its long ascent.
Is eclogite a mineral or a rock?
A high-pressure, high-temperature, coarse-grained metamorphic rock consisting primarily of pink-red garnet (almadine-pyrope variety) and green pyroxene (omphacite, a sodium-rich variety). Eclogites may also contain small amounts of other high-pressure minerals such as kyanite, quartz, hornblende, and zoisite.
What is important of eclogite rock?
Eclogites are helpful in elucidating patterns and processes of plate tectonics because many represent oceanic crust that has been subducted to depths in excess of 35 km and then returned to the surface.
What is the description of eclogite?
Definition of eclogite : a metamorphic rock consisting of soda-rich pyroxene and magnesia-rich garnet as essential minerals.
Why do diamonds form in eclogite xenoliths?
This process could explain the common occurrence of eclogite xenoliths with diamonds in metasomatic veins (e.g., Shirey et al., 2013). At pressures where diamond is stable, cratonic lithosphere is likely to have sufficient reducing conditions for carbon to exist as diamond.
Where is diamond found in eclogites?
Diamond within a few eclogites has been studied by computerized axial tomography (CAT-scan) techniques. There diamond is found in between the major silicate minerals along pathways where metasomatic fluids usually traveled (Keller et al., 1999; Anand et al., 2004), although it is unknown whether diamond always has this spatial relationship.
Is kalsilite a diamond bearing rock?
These three diamond-carrying rocks all lack the minerals melilite (Ca-Na-Mg-Al-silicate) and kalsilite (KAlSiO4), whose presence would indicate a different clan of rocks (Woolley et al., 1996) that are never diamond-bearing.
How are diamonds formed in eclogitic and peridotitic rocks?
Thus, we can expect different diamond-forming reactions in peridotitic versus eclogitic host rocks. For example, a common reaction in peridotites involves enstatite and magnesite, which react to form olivine and diamond in the presence of a fluid.