Carbonatite (/kɑːrˈbɒnəˌtaɪt/) is a type of intrusive or extrusive igneous rock defined by mineralogic composition consisting of greater than 50% carbonate minerals.

Carbonatites usually occur as small plugs within zoned alkalic intrusive complexes, or as dikes, sills, breccias, and veins.

This is because carbonatite lava flows, being composed largely of soluble carbonates, are easily weathered and are therefore unlikely to be preserved in the geologic record.

The magmatic origin of carbonatite was argued in detail by Swedish geologist Harry von Eckermann in 1948 based on his study of Alnö Complex.

[5][6] It was however the 1960 eruption of Ol Doinyo Lengai in Tanzania that led to geological investigations that finally confirmed the view that carbonatite is derived from magma.

Historically, carbonatites were thought to form by melting of limestone or marble by intrusion of magma, but geochemical and mineralogical data discount this.

This alteration assemblage produces a unique rock mineralogy termed a fenite after its type locality, the Fen Complex in Norway.

Most of the carbonatites are shallow intrusive bodies of calcite-rich igneous rocks in form of volcanic necks, dykes, and cone-sheets.

[13] Associated igneous rocks typically include ijolite, melteigite, teschenite, lamprophyres, phonolite, foyaite, shonkinite, silica undersaturated foid-bearing pyroxenite (essexite), and nepheline syenite.

[11] The Mount Weld carbonatite is unassociated with a belt or suite of alkaline igneous rocks, although calc-alkaline magmas are known in the region.

Carbonatite is known to form in association with concentrically zoned complexes of alkaline-igneous rocks, the typical example of this being Phalaborwa, South Africa.

As an example, the Palabora complex of South Africa has produced significant copper (as chalcopyrite, bornite and chalcocite), apatite, vermiculate along with lesser magnetite, linnaeite (cobalt), baddeleyite (zirconium–hafnium), and by-product gold, silver, nickel and platinum.