carbonaatit

Carbonatite is a type of igneous rock that is defined by having more than 50% of its constituent mineralogy as carbonate minerals. These carbonates are typically calcite, dolomite, or ankerite. While most igneous rocks are composed of silicate minerals, carbonatites are unusual in their mineralogical composition. They can occur in various forms, including intrusive (plutonic) and extrusive (volcanic) rocks. Extrusive carbonatites are rare and are often found at specific volcanic centers.

Carbonatites are often associated with alkaline igneous rocks and are found in specific geological settings. They are typically emplaced in rift zones and cratons, which are ancient, stable parts of the Earth's continental crust. These rocks are of significant interest to geologists due to their unique origin and their association with certain valuable mineral deposits.

Many economically important rare earth element (REE) deposits are found in or associated with carbonatites. Elements like niobium, tantalum, phosphorus, and fluorine can also be concentrated in these rock types. Examples of major carbonatite occurrences include the Oldoinyo Lengai volcano in Tanzania, which erupts a unique natrocarbonatite lava, and the Mount Weld carbonatite in Western Australia, a significant source of rare earth elements. The formation of carbonatites is thought to involve processes deep within the Earth's mantle.