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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



rocks of magmatic or metasomatic origin, composed primarily of carbonates (calcite, dolomite, ankerite) and spatially related to complexes of ultrabasic-alkalic composition. The term “carbonatite” was introduced by the Norwegian petrographer W. Brûgger (1921). He also proposed that calcite carbonatites be called sövites, dolomite carbonatites be called rauhaugites, biotite-dolomite veined carbonatites be called befor-sites, and red-colored carbonatites (in which the carbonate is partially replaced by iron oxides, primarily hematite) be called redbergites.

The complexes of ultrabasic-alkalic rock in which carbonatites are found are generally located along major faults on the platforms. They may be “blind,” that is, not reach the earth’s surface, or “open,” reaching the surface in the form of volcanoes that erupt carbonatite lava (the Oldoinyo Lengai volcano in Tanzania). Geophysical data show that the complexes are dozens of kilometers deep. Carbonatites make up the central parts of the complexes, forming stocks and chimney deposits measuring from 0.1 to 15–20 km and more in area as well as irregularly shaped deposits, branching zones, stockworks, and circular, conical, and radial dikes. In open-type complexes they fill volcanic vents, frequently cementing brecciated volcanic rocks. Where carbonatites develop on ultrabasites and ijolites, in some complexes there occur forsterite-apatite-magnetite rocks with small amounts of calcite (phoscorites, kamaphorites); these rocks are sometimes high-quality magnetite ores (for example, Kovdor on the Kola Peninsula in the USSR) or are rich in apatite (the Palabora Massif in the Republic of South Africa). When carbonatites develop on nepheline syenites, aureoles of albitites with tantalum-niobium mineralization often form.

Carbonatites are multistage formations that form in the temperature interval between 600° and 300°C. Early-stage carbonatites consist of calcite, diopside or forsterite, biotite or phlogopite, apatite, and magnetite. They are enriched with Ti, Zr, Ta, Nb, and U.

Carbonatites of the late stages consist of 80–95 percent dolomite or ankerite and calcite, and, more rarely, siderite and stron-tianite. They contain alkaline amphiboles, serpentine, ferroferriphlogopite, aegirite, chlorite, and epidote. Sulfides typically appear (pyrite, pyrrhotite), as well as fluorite, barite, magnetite, rutile, pyrochlore, lueshite, columbite, fersmite, bur-bankite, bastnaesite, parisite, carbocernaite, and ancylite. Carbonatites are characterized by high concentrations of Sr, Ba, F, Nb, Ce, Th, Pb, Zn, and Mo.

Carbonatites and their associated rocks are an important form of mineral deposit. Related to them are large deposits of phlogopite and vermiculite (Kovdor and Gulinskoe in the USSR), iron (Kovdor in the USSR, Palabora in the Republic of South Africa), phosphorus (Palabora in the Republic of South Africa, Sukulu in Uganda), and rich deposits of niobium ore (Araxá in Brazil, Lueshe in Zaïre, Oka in Canada), well as deposits of tantalum (Nqombwa, Zambia), zirconium (Palabora, Republic of South Africa), rare earths (Mrima, Kenya), copper (Palabora, Republic of South Africa), fluorite (Tagna, USSR), and raw materials for cement and lime (Tororo and Sukulu in Uganda). In addition, it is possible to extract barite and strontianite from some of the deposits. Under conditions of hypergenesis a weathering mantle develops on carbonatites; the content of useful components (apatite, pyrochlore, bastnaesite) in it is three to five times greater than in bedrock.


Ginzburg, A. I. [et al.] “Redkometal’nye karbonatity.” In Geologiia mestorozhdenii redkikh elementov, fasc. 1. Moscow, 1958.
Ginzburg, A. I., and E. M. Epshtein. “Karbonatitovye mestorozhdeniia.” In Genezis endogennykh rudnykh mestorozhdenii. Moscow, 1968.
Smirnov, V. I. Geologiia poleznykh iskopaemykh, 2nd ed. Moscow, 1969.
Karbonatity. Edited by O. Tuttle and J. Gittins. Moscow, 1969. (Translated from English.)
Heinrich, E. W. The Geology of Carbonatites. Chicago, 1966.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The MnO and SrO contents of carbonate minerals may be used as indicators to distinguish carbonatites from marble.
The simulated conditions aim to approximate the chemistry of simple aqueous-carbonic fluids, as well as their driving mechanisms for REE mobilization associated with REE deposit formation in carbonatites and alkaline systems.
However, comparisons between Ti-clinohumite from the Cienaga Marbles and that found in JAC carbonatites, xenoliths in kimberlites, RGP Alpine peridotites and Archean ultramafics may carry out as shown in Figure 11, highlighting that the Ti-clinohumite analyzed in this study represents not only an almost pure in Mg but also may be considered as the most Mg-rich and TiO2-rich varieties around the world for skarn environments.
One interesting commonality in a number of finds is a large amount of carbonatites, sometimes formed by lava a long time ago.
- Although Tanzania has significant known REE deposits and carbonatites country remains under-explored.
Although carbon-based lavas, known as carbonatites, are found throughout history, the Oldoinyo Lengai volcano, located in the East African Rift in northern Tanzania, is the only place on Earth where they are actively erupting.
It is also found in a variety of exotic settings such as kimberlites (Malkov 1974) and carbonatites (Lee et al.