Rare Metal-Bearing Pegmatites in Parts of Southern Karnataka, India

Abstract

Several pegmatites containing commercially viable sources of columbite-tantalite have been located in the Holenarsipur, Kdshnarajapet and Nagamangala schist belts. The pegmatites in Holenarsipur schist belt near Hassan, contain columbite-tantalite, rich in both niobium and tantalum and carry appreciable amounts of beryl. The Nagamangala schist belt is particularly rich in tantalite-bearing (Ta₂O₅ 50-70%) pegmatites.

Analysis of feldspars from the three different belts indicates that they are potassic in the Nagamangala belt while they are sodic in the case of two other belts. Trace element analysis of muscovite indicates an average of 42, 242, 107, 325 ppm of Be, Nb, Sn and Li in Nagamangala belt as against 55, 114, 127 and 329 ppm respectively in Holenarsipur belt. Presence of considerable amount of bismutite in Mundur pegmatite and traces of spodumene and pollucite in Nagamangala belt have been confirmed.