Indication for copper mineralization associated with metabasalt in gaudur area, hutti-maski schist belt, Raichur district, Karnataka

This report presents preliminary results of indications for sulfide mineralization near Gaudur in Raichur district, Karnataka. Indications for copper mineralization are seen in the sheared and altered schistose metabasalt of Hutti Schist Belt. The mineralization is confined in N-S to NNW- SSE direction with dip ranging from vertical to sub-vertical. Petrographic study reveals that metabasalt have undergone green schist facies metamorphism. The metabasalt is characterized by presence of chlorite, epidote, albite, actinolite, calcite and minor quartz. Alteration in the form of chloritization and epidotization of ferromagnesian minerals is also observed. Numerous anastomosing quartz-calcite veins are seen parallel to the foliation and shear planes. At places, the outcrops of schistose metabasalt show profuse staining by secondary copper minerals like malachite and azurite. Freshly broken rock shows presence of sulfides as disseminations and also along quartz-calcite veins. Bed rock samples of mineralized metabasalt show high values with some grab samples showing copper values up to 8.0%. The metabasalt is associated with granites in the study area which are predominantly dioritic and pink porphyritic granite which show intrusive relationship with the metabasalt. The contact zone of metabasalt and granitoids are generally sheared and could be the possible loci for sulfide mineralization. Petrographic and EPMA studies of ore samples suggest that there are two stages of mineralizing event. The first one is of syngenetic type which occurs as fine disseminations within the schistose metabasalt and the second one is epigenetic, represented by remobilized sulfides along veins. Although the Hutti Schist Belt is well known for gold mineralization, presence of indications for copper mineralization within the metabasalt near Gaudur show that it may have a potential for copper mineralization as well.