Thermometry sulphur isotopes

Sulphur isotopes (32,33,34,36S) fractionate strongly in the earth s crust because (1) the element occurs in different oxidation states with differential preference for heavy isotopes, (2) the existence of volatile and easily soluble compounds favors kinetic separations, and (3) it is involved in biogenic cycles where the oxidation state is easily changed and kinetic processes are important. From theoretical calculations of Bigeleisen (1961) and data on the isotopic properties of sulphur compounds by Sakai (1957, 1968), the amount of S isotope fractionation and its temperature dependence is known. The information on experimental inorganic isotope fractionation in coexisting sulphide minerals which occur naturally was summarized by Thode (1970), who also discussed the application of S isotopes from sulphides for geo thermometry (cf. also Sakai, 1971). Analytical work on all types of sulphur compounds which occur in nature has been reviewed by Nielsen (1973). 

Rafter TA (1957) Sulphur isotopic variations in nature Part I. The preparation of snlphur dioxide for mass spectrometer examination. New Zealand J Sci Techn B38 849 Rathmell MA, Streepey M, M., Essene EJ, van der Pluijm BA (1999) Comparison of gamet-biotite, ealeite-graphite, and calcite-dolomite thermometry in the Grenville Orogen Ontario, Canada. Contrib Mineral Petrol 134 217-231... 

Sulphur isotope fractionation between sulphide and sulphate phases — sulphur isotope thermometry... 

Tigure 7.24 Parddoning of between mineral pairs and H2S-SO2 as a funedon of temperature. These fracdonadon curves can be used -in sulphur isotope thermometry and indicate that the. greatest fracdonadons are between sulphides, and sulphate minerals. 

The sulphide phases are not in isotopic equilibrium with each other, for the results of sulphur isotopic thermometry do not agree with the known temperature of the vent fluid. 

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