Alkaline–Carbonatite Complexes of India: A Review of Geological Evolution and Critical Mineral Resources

The alkaline–carbonatite complexes of India constitute some of the most significant repositories of rare earth elements (REEs), niobium (Nb), phosphorus (P), barium (Ba), strontium (Sr), uranium (U), thorium (Th), and other critical minerals that are indispensable for modern technologies and the global transition towards clean energy. These complexes are predominantly distributed within the Precambrian shield of Peninsular India and are spatially associated with deep-seated crustal fractures, continental rift systems, and major shear zones, reflecting prolonged mantle-derived alkaline magmatism and tectonic reactivation. Extensive geological, geochemical, and geochronological investigations over the past five decades have considerably improved the understanding of the origin, evolution, and economic significance of Indian alkaline–carbonatite complexes. This review synthesizes the previous work on geological setting, geochemistry, isotope characteristics, petrogenesis, tectonic evolution, and critical mineral resources of the alkaline–carbonatite complexes of India. The research work consistently demonstrate that Indian carbonatites originated from mantle-derived carbonatitic magmas that evolved through varying degrees of partial melting, fractional crystallization, carbonate–silicate liquid immiscibility, metasomatism, hydrothermal alteration, fenitization, and supergene enrichment. The principal alkaline–carbonatite provinces of India include the Amba Dongar, Kamthai, Sung Valley, Samchampi, Newania, Mundwara, Sarnu–Dandali, Sevathur, Samalpatti, Hogenakkal, Pakkanadu, Pikkili and Kambamettu complexes. Among these, the alkaline–carbonatite complexes of Tamil Nadu represent one of the most extensively investigated provinces, providing important constraints on mantle evolution, crust–mantle interaction, alkaline magmatism, and critical mineral enrichment. Recent advances in mineral chemistry and exploration techniques have further highlighted the strategic importance of Indian carbonatites as potential domestic sources of rare earth elements and other critical minerals. This article summarizes the present understanding of Indian alkaline–carbonatite complexes and identifies future directions for geological research and mineral exploration.