Northeast identified as new hotspots for rare earth & critical minerals: GSI

Guwahati, June: The states of Assam and Arunachal Pradesh have emerged as promising zones for graphite, vanadium, REEs, base metals, gold, coal and limestone, while Meghalaya and Nagaland hold extensive resources of limestone, coal, and minor strategic metals, a Geological Survey of India (GSI) report has revealed.

Rare Earth Elements (REEs) are a group of 17 chemically similar elements (including lanthanum, neodymium and yttrium) critical in magnets, electronics, and green technologies. The REEs – grouped into light and heavy categories – are indispensable in modern electronics, wind turbines, electric vehicles and defence systems.

“Since 2015, several high-impact resource estimations have been made in the region. These include 24.81 million tonnes of graphite and 17.17 million tonnes of vanadium in Arunachal Pradesh; over 6,600 million tonnes of limestone in Meghalaya; more than 1,400 million tonnes of limestone in Assam and strategic REE resource of 2.15 million tonnes in Arunachal Pradesh and 28.64 million tonnes in Assam,” the report said.

In Arunachal Pradesh, the Lodoso area in Papum Pare district has yielded a delineated resource of 2.15 million tonnes of REE-bearing ferruginous phyllite, with average grade of 1.08 per cent total REE (including Yttrium). Significant Nd (Neodymium) concentrations have also been recorded from West Siang and East Kameng districts. Assam’s Jashora and Samchampi alkaline complexes have demonstrated encouraging results through pedo-geochemical surveys and trench sampling. These complexes have returned REE concentrations ranging from 1000 to 5000 ppm, alongside associated elements such as Nb and Y.

The granite gneisses within Assam Meghalaya Gneissic Complex (AMGC) is also potential for REE and Rare Metal (RM).

In Meghalaya, the Sung Valley ultramafic-alkaline-carbonatite complex has presence of titaniferous bauxite cappings.

Assam’s geology is dominated by the sedimentary sequences of the Brahmaputra and Barak plains, the granitic and gneissic cores of the Mikir Hills and the Shillong Group rocks in central Assam. The State is traditionally known for its oil and natural gas reserves, but it also hosts valuable deposits of iron ore, glass sand, limestone, and REEs.

Assam’s largest non-energy mineral resource is limestone, with over 1,490 million tonnes delineated from Dima Hasao district alone. These resources, hosted in the tertiary formations of the Jaintia Group, are suitable for cement and other industrial applications.

Iron ore deposits with an estimated resource of 18.29 million tonnes at an average grade of 37.45 per cent Fe have been reported from the Chandardinga area in Dhubri district.

Glass sand with high silica content has been identified in Nagaon and Karbi Anglong districts, while placer gold has been recorded from the Subansiri River basin in upper Assam. Although modest in grade, these gold occurrences are important indicators of potential upstream mineralization, the report said.

Quaternary sediments are widespread in the Brahmaputra and Barak River basins and form the fertile plains of Assam and Tripura. Though these areas are generally less prospective for hard-rock minerals, recent studies have indicated potential for placer gold and groundwater-hosted lithium, it added.

Between 2015 and 2024, GSI has carried out more than 200 mineral exploration projects and delineated 38 potential blocks in the region across multiple states—Arunachal Pradesh, Assam, Meghalaya, and Nagaland—through Geological Reports (GR’s) and Geological Memorandum (GMs’).