Multiple sulfur isotope fractionation in hydrothermal systems in the presence of radical ions and molecular sulfur

Abstract This study is aimed to evaluate the role played by the sulfur radical ions (S3•− and S2•−) and molecular sulfur (S0) on sulfur isotope fractionation and to investigate if these species may leave an isotope fingerprint in hydrothermal systems. For this purpose, we combined i) experiments using a hydrothermal reactor with aqueous S3•−(S2•−)-S0-sulfate-sulfide fluids and pyrite across a wide range of temperatures (300-450°C), pressures (300-800 bar), fluid acidity (4