Geochemistry of braunite and associated phases in metamorphosed non-calcareous manganese ores of India

@article{Bhattacharyya1984GeochemistryOB,
  title={Geochemistry of braunite and associated phases in metamorphosed non-calcareous manganese ores of India},
  author={P. K. Bhattacharyya and Somnath Dasgupta and Masato Fukuoka and Supriya Roy},
  journal={Contributions to Mineralogy and Petrology},
  year={1984},
  volume={87},
  pages={65-71}
}
In the metamorphosed manganese oxide ores of India, braunite is ubiquitous in all assemblages from chlorite to sillimanite grades. Chemical analyses of braunite from different prograde assemblages confirm the presence of a fixed R2+ (=Mn2++Mg+Ca) SiO3 molecule in the mineral. Element partitioning between coexisting braunite and bixbyite indicates a near-ideal mixing of Fe+3/ -Mn+3 in the phases. This also indicates that braunite became relatively ferrian while equilibrating with associated… 
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