Sulphur Isotope Abundance Variations in Sulphides of the Dharwar Craton-Part I: Kalyadi

Sulphur isotope abundance variations in chalcopyrite, pyrite and pyrrhotite samples from the sulphide deposits of Kalyadi have been measured with a double-collector mass spectrometer provided with digital ratio recording. The results fall into two groups - one with a near-zero per-mil value and another with a small positive value ∼5‰. Data on coexisting sulphide minerals enable temperatures of deposition to be calculated, these being low ∼250° C. The Ohmoto-procedure is adopted, and the range of δ³⁴S values of the minerals explained by assuming an initial total sulphur δ³⁴S_TS value and a range of pH and f_O2 values that are plotted on an f_S2 - f_O2 diagram consistent with the stability fields of the minerals.