Sulphur isotope compositions of sulphides and sulphates, DSDP Leg³⁷

Abstract

Sulphur isotope abundances were determined for 15 sedimentary and 9 basalt specimens from DSDP Leg 37 cores. Sedimentary sulphides had δ 34 S values as low as −54‰, which is consistent with isotopic selectivity during bacterial sulphate reduction. The δ 34 S values for soluble sedimentary sulphates were generally lower than ocean water sulphate. This is probably due to contributions of oxidized sedimentary sulphides. Pyrite in basalt fractures had δ 34 S values ranging from −33‰ to −5‰. An unique interpretation of these data is not possible at this time.