Why carbonatites is important?
Alkaline-carbonatite complexes are significant sources of Cu, apatite, fluorite, vermiculite, and other commodities. Most modern studies on carbonatites address their origin and aim to improve our understanding of the Earth’s mantle (Bell and Tilton 2001.
How are carbonatites formed?
Carbonatites are rare, peculiar igneous rocks formed by unusual processes and from unusual source rocks. Three models of their formation exist: direct generation by very low degree partial melts in the mantle and melt differentiation. liquid immiscibility between a carbonate melt and a silicate melt.
How do you identify carbonatite?
Carbonatites are defined in the IUGS system of classification as: “igneous rocks composed of more than 50 modal per cent primary (i.e., magmatic) carbonate (sensu lato) and containing less than 20 wt. % SiO2” (Le Maitre 2002).
How is carbonatite magma formed?
Experiments have confirmed that carbonatite magmas may be generated through one of the following mechanisms: (1) by partial melting of carbonated peridotites (e.g. Wyllie & Huang, 1975, 1976a; Eggler, 1978; Wallace & Green, 1988), (2) by crystal fractionation of some silicate–CO2 magmas (e.g. Franz & Wyllie, 1967; …
What is the composition of Charnockite?
Charnockite is a granofels that contains orthopyroxene, quartz, and feldspar. Charnockite is frequently described as an orthopyroxene granite. Granites are felsic rocks that usually contain no or very little pyroxene.
Where are carbonatites found?
Overall, 527 carbonatite localities are known on Earth, and they are found on all continents and also on oceanic islands. Most of the carbonatites are shallow intrusive bodies of calcite-rich igneous rocks in form of volcanic necks, dykes, and cone-sheets.
Why are carbonatites rich in REE?
During the evolution process, the carbonatite rocks or dykes rich in REE were formed through the immiscibility of carbonate-silicate magma and fractional crystallization of carbonate minerals from carbonatite magma. A simple magmatic evolution process cannot ensure massive enrichment of REE to economic values.
What minerals are in carbonatite?
Carbonatites are a relatively rare type of igneous rock composed of greater than 50 vol % primary carbonate minerals, primarily calcite and/or dolomite, and contain the highest concentrations of REEs of any igneous rocks.
How is a Lamprophyre formed?
Distribution. Lamprophyres are usually associated with voluminous granodiorite intrusive episodes. They occur as marginal facies to some granites, though usually as dikes and sills marginal to and crosscutting the granites and diorites. In other districts where granites are abundant no rocks of this class are known.
Is charnockite igneous or metamorphic?
charnockite, any member of a series of metamorphic rocks with variable chemical composition, first described from the state of Tamil Nadu in southern India and named for Job Charnock. The term is often limited to the characteristic orthopyroxene granite of the series.
What are the characteristics of carbonatites?
• Carbonatites are primarily composed of calcite (or dolomite) of igneous origin and silicate mineral are also present. • Importance: Academic-Carbonatite are derived from mantle. Economic- Carbonatites contain rare earth elements. 4.
What is the oxide content of REE carbonatite?
REE oxide content of 7.98 percent Dominantly light REEs Carbonatite: A rare igneous carbonaterock containing 50 percent or more carbonate minerals. Mountain Pass processing facilities on-site
What is the composition of sulphide Queen carbonatite?
Mountain Pass mine Sulphide Queen carbonatite (Mountain Pass deposit) REE oxide content of 7.98 percent Dominantly light REEs Carbonatite: A rare igneous carbonaterock containing 50 percent or more carbonate minerals.