Fluid inclusion characteristics of basemetal mineralization in southern part of Aladahalli - Nuggihalli Schist belt, Western Dharwar Craton, Karnataka, India

Aladahalli-Nuggihalli Schist belt of Karnataka in Western Dharwar Craton is well known for its remobilized volcanic exhalative type base-metal mineralization. The schist belt comprises metamorphosed mafic-ultramafic rock assemblage, traversed by quartz veins. The study area belonging to the southern extension of the schist belt is chosen on the basis of bipolar aero-magnetic anomaly (magnetic high) and higher order EM channels (4 th , 5 th and 6 th ) along with favourable geological conditions for mineralization. Lithology of the area includes metabasics (dominant) and meta-ultramafics intricately associated with pegmatite dykes and quartz veins. Subsurface mineral exploration programmes carried out in Aladahalli belt shows a close link between the quartz veins and sulphide mineralisation. Fluid inclusion study has been carried out on quartz samples from these veins to characterise the composition and P–T condition of entrapment of fluid inclusions. Three contrasting types of fluid inclusions are reported suggesting moderate to low salinity hydrothermal fluid pertaining to shallow-level epithermal condition.