Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

Navin Goyal ¹, Siby K. Varughese ¹, P. K. Hansda ¹, S. Ramachandran ¹, Rajendra Singh ²

Affiliations
1 Atomic Minerals Division, Baroda - 390 001, IN
2 Atomic Minerals Division, Hyderabad - 500 016, IN

Abstract

The Precambrian Champaner Group of rocks are intruded by Godhra granites in Jambughoda area. Significant uranium mineralisation has been located in the fractures in the dolomitic limestone of Lower Champaners with uraninite occurring as the primary uranium mineral. The geochemical features observed for the granites suggest that the granite melt, originated by the partial melting of relatively silicic crust, was further modified by fractionation processes during which uranium was concentrated in the late magmatic and subsequent hydrothermal fluids. The Champaner deformation resulted in the formation of WNW-ESE regional fracture system and crush zones, thus making the rocks highly penneable for the passage of uranium-rich hydrothermal fluids and offering open spaces for precipitation of uranium under suitable physicochemical conditions.

Keywords

Geochemistry, Champaners, Granites, Uranium, Gujarat.

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Navin Goyal ¹, P. C. Pant ², P. K. Hansda ³, B. K. Pandey ⁴

Affiliations
1 Atomic Minerals Directorate For Exploration and Research, Jamshedpur-831 002, IN
2 Atomic Minerals Directorate For Exploration and Research, Jamshedpur-831 002
3 Atomic Minerals Directorate For Exploration and Research, New-Delhi-110 066, IN
4 Atomic Minerals Directorate For Exploration and Research, Hyderabad-500 016, IN

Abstract

The Precambrian Godhra Granite occurring in parts of central Gujarat, intrudes the metasediments of Lunavada and Champaner Groups. RbSr isochron based on 14 whole rock samples of the Godhra Granite gives an age of 965±40 Ma, with an initial ⁸⁷Sr/⁸⁷Sr ratio of 0.7109±0.0015. Geochemical data indicate its origin by partial melting of crustal rocks in post-orogenic environment.

Keywords

Godhra Granite, Peraluminous Granite, Rb-Sr Isochron, Crustal Source, Gujarat.

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