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

B. V. K. Raju ¹, N. Murali Sivaram ², B. S. Ganga Rao ², K. K. V. S. Raju ²

Affiliations
1 Dept. of Geology, Andhra University, Visakhapatnam-530 003
2 Dept. of Geology, Andhra University, Visakhapatnam-530 003, IN

Abstract

Chalcophanite (Zn, Cu) Mn₃0₇.3H₂0 is reported from Gottivada Manganese Ores (17°32'O"N - 82°44'50" E). The mineral crystallises in the triclinic system with a=7.5201; b=7.5102, c=8.1324 Å; α=90°, β=116°40',γ=120° space group P1. The structure of chalcophanlte is characterised by single sheets of water molecules grouped in open double hexagon rings alternating with double oxygen layers. The seventh octahedral site in the structure is occupied by Mn, Zn and Cu atoms linked to the triads of oxygens. Bonding of the vacanies in the Mn layer complete the octahedral co-ordination with the triads of water molecules. Physical, optical and chemical properties of copper bearing chalcophanite are described in detail. The chalcophanite is a secondary colloform manganese mineral formed from the gels that contains copper and zinc atoms with manganese hydrolizates.

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V. Sreekantiia Raju ¹, B. V. K. Raju ¹, K. K. V. S. Raju ¹

Affiliations
1 Department of Geology, Andhra University Visakhapatnam 530003, IN

Abstract

Inclusions of monazite and zircon occur in the apatite porphyroblasts in a pegmatite associated with a phosphate mine from Sitarampuram in the Eastern Ghats. Apatite is Sr-bearing with high Sr/Mn ratio whereas monazite and zircon are Th- and U-bearing, respectively. Local spatial and short term temporal changes in the original solution, mostly controlled by diffusion induced leaching and osciallatory compositional transfer variations, appear to have admitted accessory monazite and zircon into the host apatite, with the source material for all the three being hydrothermal solutions.

Keywords

Monazite, Zircon, Mineral Chemistry, Eastern Ghats, Andhra Pradesh.

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