• C Borreswara Rao

      Articles written in Proceedings – Section B

    • Electron-probe microanalysis and geothermometry of sphalerite in the ingaladhal sulphide lode, chitradurga district, mysore state

      K V S Acharyulu C Borreswara Rao

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      Sphalerites coexisting with pyrrhotite and pyrite in Ingaladhal lode, Chitradurga District, Mysore State, were analysed for Fe, Mn, Cd, and S contents using an electron probe microanalyser. Four among the above samples were also analysed by X-ray diffraction using Cu-Kα radiation. Unit cell dimensions of sphalerites were calculated using Skinner’s equation. The iron content of sphalerite shows sympathetic variation with its temperature of formation. The estimated temperatures of formation of sphalerite, using Kullerud’s curve ranges between 340° C.–460° C. From the temperature measurements it is concluded that the ore body was formed at a single period of crystallization and that it would continue at depth.

    • Studies on the pyrrhotite from the Ingaladhal sulphide lode, chitradurga district, mysore state

      K V S Acharyulu C Borreswara Rao

      More Details Abstract Fulltext PDF

      X-ray studies, optical studies and chemical composition of pyrrhotite indicate that in the Ingaladhal copper mine it occurs in both hexagonal and monoclinic modifications as well as in transitional forms. The monoclinic phase might have formed by inversion from the hexagonal phase. The hexagonal form has a composition that appropriates to solvus temperatures of < 300°–360°C. Heated monoclinic and hexagonal monoclinic mixtures of pyrrhotite yielded temperatures ranging from 425°–460°C. From the questionable validity of the pyrrhotite geothermometer it is concluded that the temperature estimates based on the pyrrhotite solvus cannot be used to know the temperature of formation of pyritepyrrhotite assemblage in the Ingaladhal sulphide lode.

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