GEOCHEMISTRY OF GRANITES OF JAMBUGHODA, PANCHMAHALS DISTRICT, GUJARATAND URANIUM MINERALIZATION IN CHAMPANER GROUP

The Precambrian Champaner Group of rocks are intruded by Godhra granit es in Jambughoda area. Significant uranium mineralisation has been loc ated in the fractures in the dolomitic limestone of Lower Champaners w ith uraninite occurring as the primary uranium mineral. The geochemica l features observed for the granites suggest that the granite melt, or iginated by the partial melting of relatively silicic crust, was furth er modified by fractionation processes during which uranium was concen trated in the late magmatic and subsequent hydrothermal fluids. The Ch ampaner deformation resulted in the formation of WNW-ESE regional frac ture system and crush zones, thus making the rocks highly permeable fo r the passage of uranium-rich hydrothermal fluids and offering open sp aces for precipitation of uranium under suitable physicochemical condi tions.