Experimentally determined sulfur isotope fractionations between sulfide minerals

Preliminary experimental measurements have been made of the sulfur isotopic fractionation between pyrite, sphalerite and galena at 340–690°C. Sulfur isotopes were exchanged between each metal sulfide and liquid sulfur. At equilibrium the sequence of34S/32S ratios is pyrite>sphalerite>galena, in agreement with measurements of natural assemblages. Temperatures calculated on the basis of intermineral fractionations for metamorphosed ore deposits give: Heath Steele, N.B. (upper greenschist facies): 300°C; Broken Hill, N.S.W. (hornblende granulite facies): 540°C.