Petrology of Mn carbonate-silicate rocks from the Gangpur Group, India

Textural characteristics and chemical composition of constituent phases suggest that the mineral assemblages reflect a complex relationship between protolithic composition, variation of XCO2 (<0.2 to ∼0.3) and oxygen fugacity. A variation of XCO2 and fO2 would imply internal buffering of pore fluids through mineral reactions that produced diverse assemblages in the carbonate bearing manganiferous rocks. A minor change in temperature (from around 400 to 450 °C) does not appear to have had any major influence on the formation of different mineral associations.