δ34S character of organosulfur compounds in kerogen and bitumen fractions of sedimentary rocks

Hydropyrolysis (HyPy) of S-containing oil mature rock samples from two geologic settings each produced much higher concentrations of organosulfur compounds (OSCs) compared to their free occurrence in the bitumen. The δ34S values of the most abundant OSCs from the kerogen and in the bitumen, were measured by gas chromatography inductively coupled plasma mass spectrometry (GC-ICP-MS). DBT and mDBTs from the HyPy processed kerogen fractions showed a distinct 34S depletion, with δ34S values up to 12‰ lighter than their bitumen occurrence. The different δ34S values of OSCs from the kerogen and bitumen fractions is likely reflective of differences in timing of production, reduced sulfur sources or organic sulfurisation mechanism.