Occurrence of Placer Gold in the Marlagalla-Allapatna Areas, Mandya District, Karnataka

Abstract

Occurrence of placer gold is reported for the first time in the insitu and colluvial gravels derived from amphibolite/hornblende schist, associated pegmatite and quartz veins of Nagamangala schist belt in Marlagalla –Allapatna areas, Mandya district, Karnataka. Gold occurs in the form of small nuggets, measured up to 3mmx4mm in size and 0.2 gram in weight. The host rock is amphibolite which are intruded by numerous pegmatite and quartz veins. The pegmatites are complex, highly evolved type and contain economic concentration of rare metal bearing minerals viz., columbite-tantalite, beryl and spodumene. Prolonged weathering of these rocks resulted in liberation of gold from host rocks and concentrated in the insitu/eluvial and colluvial gravels. The present finding of gold opens up a new vista for further detailed geological/geochemical exploration to establish and evaluate gold potential in the eluvial, colluvial gravels as well as in the other lithounits of Nagamangala schist belt in Marlagalla-Allapatna areas.