Charnockite

Classification：Metamorphic Rock

An anhydrous metamorphic rock, it is referred to as granite, and not from the underground charnockite magma crystallized.

Charnockite is a component of the equivalent of granite and tonalite gneiss, and coarse grain of similar appearance. The main minerals are quartz, potash feldspar, fermented plagioclase, pyroxene and garnet, sometimes with diopside. No plagioclase or a small number of more - feldspar. The potash feldspar is usually a micro plagioclase, which is characterized by the stripe of the stripe feldspar not the feldspar but the feldspar, even the feldspar, and sometimes the anti stripe feldspar. [1] Charnockite is a Early Cambrian pyroxene intermediate acid intrusive rock or metamorphic rock, which is related to high-grade metamorphism. It is composed of xperite, quartz, plagioclase and alkaline feldspar. When plagioclase content exceeds alkaline feldspar, it is called perilla granodiorite, otherwise, it is a narrow Charnockite.

Feature：
There are ubiquitous melt metasomatic structures in Charnockite, which are mainly composed of residual crystalline minerals and crystalline minerals. The study of the formation and composition of fluid inclusions in Charnockite and metamorphic cases found that the rich CO2 fluid inclusions and the rich N2 fluid inclusions were all derived from the deep mantle.
Charnockite is usually coarse-grained, massive or gummy, and its granitic structure is about 2.67, and its color is deep. The quartz is soot to light blue, with very small rutile, zirconium rich mineral or many fissures and CO2 inclusions; plagioclase is more feldspar or feldspar, common sodium long stone law double crystal and anti stripe structure; alkaline feldspar is normal feldspar or micro plagioclase, often showing stripe structure (the composition of stripe is often more, medium feldspar); Generally, perenite is polychromatic. Garnet is a characteristic mineral of Charnockite. Sometimes it contains a small amount of clinopyroxene, common hornblende and biotite.
Composition editing
The SiO2 content (weight%) of the whole rock is about 70%, K2O>Na2O and K2O are about 3 ~ 7%, and REE, LREE/HREE and delta Eu vary greatly.

Editors：
Charnockite is formed at high temperature (>700 C) and high pressure (>15 km depth) granulite phase change rock area, which is an igneous rock of advanced region metamorphic origin or metamorphic rock interbedded with granulite. The undertransgression of basic magma made this area undergo the first phase of granulite facies metamorphism, and the existence of CO2 fluid inclusions in the mantle made the system a (H2O) very low (a (H2O) =0.1 ~ 0.3), and the metamorphism of granulite facies did not produce melting. The mantle derived magmatic activity ceased, and the area experienced second stages of isobaric cooling. At this time, the action of deep source rich CO2 fluid weakened, the activity of water increased, a (H2O) =0.65 ~ 0.75, thus producing magma, and the new magma was metasomatism in the early formation of metamorphic minerals, which made the refractory metamorphic minerals such as perilla pyroxene, garnet and Dan Xiehui stone formed in the early stage, and the magma was basic with the decrease of temperature. In situ - semi - original crystallization of Charnockite. It exposed in depth after erosion of the Precambrian basement complex rocks, often with granulite, sometimes with anorthosite symbiosis.