Gold Mineralization at Paramanahalli Prospect, Chitradurga Greenstone Belt, Western Dharwar Craton, Karnataka, India

ABSTRACT Paramanahalli gold prospect is hosted by deformed metamorphosed volcano-sedimentary rocks of the Chitradurga Group. Mineralization is confined to altered host rocks and quartz veins, and structurally controlled by NNW-SSE trending ductile to brittle-ductile shear zones. Surface indication of mineralization is found in the form of sulfide-rich quartz-ankerite veins with pyrite disseminated in host rocks. Detailed petrographic studies indicate a mineral assemblage of chlorite-1 ± biotite ± albite ± quartz in metabasalt formed by low-grade metamorphism. Microstructures such as brecciation, microfractures, micro folds, and strain fringes indicate that the metamorphosed volcano-metasedimentary rocks (metabasalt, phyllite, greywacke) experienced brittle-ductile deformation. Carbonatization and sulfidation are common hydrothermal alterations in the areas of oxide facies of the Banded Iron Formation (BIF), where gold is enriched. Altered metabasalt and BIF contain a significant amount of sulfides with native gold. The above studies indicate that mineralization at Paramanahalli was associated with deformation and alteration processes. Hence, an attempt has been made to understand the genetic aspects of gold mineralization at the Paramanahalli gold prospect based on petrography and mineralogy of altered host rocks.