CARBONATITES : OCCURRENCES, CHARACTERISTICS AND THEIR ECONOMIC SIGNIFICANCE

Carbonatites are rare igneous rocks having more than 50% of carbonate minerals. The mineralogy of the carbonatites is highly variable and contains calcite, dolomite, ankerite, natrolite, sodalite, apatite, magnetite, barite, fluorite, mica etc. in variable proportion. Geochemically the carbonatites also have very wide variation in major, trace and REE composition. There are only 330 known carbonatite occurrences in the world including one active volcano.Indiaalso has the carbonatite occurrences. So far about 20 major and 11 minor carbonatite occurrences have been reported fromIndia. Due to the complex mineralogical and chemical composition, the carbonatites are one of the valuable sources for many important minerals especially REE, niobium, igneous phosphate, strontianite, fluorite, apatite, uranium etc.