Base Metal Mineralisation Associated with Hydrothermal Alteration in Felsic Volcanic Rocks in Proterozoic Betul Belt at Bhuyari, Chhindwara District, Madhya Pradesh

The southeastern part of the Proterozoic Betul Belt exposes a Felsic-Dominated sequence around Bhuyari in the Kanhan river sector. The felsic volcanic rocks, identified as rhyolite occur in the form of two mappable bands in a milieu of biotite ± hornblende bearing Quartzo-Feldspathic rocks of subvolcanic affinity. A very well developed zone of hydrothermal alteration is recognized in rhyolite that occurs to the immediate south of Bhuyan village. The hydrothermal facies mapped in the alteration zone include sericite - muscovite-bearing rhyolite, phlogopite± spessartite biotite schist and trernolite (± actinolite) - rich rock with serpentine, talc, epidote and dolomitic carbonates. Discrete grains of fluorite and REE bearing flour carbonates form part of the hydrothermal mineral assemblage. Apart from the magnesian enrichment, the occurrence of spessartite garnet, epidote and sporadic development of staurolite indicate significant fluxes of manganese, calcium and alumina in the zone of hydrothermal alteration. The alteration is attendant with polymetallic base metal mieralisation which is invariably Zinc-Dominated. Bedrock samples and selected channel sampling indicate that the Tremolite-Rich facies is intensely mineralized, followed by phlogopite ± garnet biotite schist. Primary sulphides observed in a dug well section are pyrite, sphalerite galena and chalcopyrite which occur as disseminations and also as several millimeter thick semiconformable veins Rare quartz Phenocryst-Groundmass relationship in the mineralized host rock from the dug well provide incontrovertible evidence for the volcanic affinity of the base metal mineralisation.