Bitumen samples have been chosen either from natural oil seepages and outcropping oil-stained reservoirs or archaeological bitumens from excavations in Iraq and Pakistan. Asphaltenes have been extracted from the bitumens. X-ray absorption near edge fine structure (XANES) spectroscopy at the S L-edge and K-edge has been employed to follow the oxidation effects on various sulphur moieties of the asphaltene fractions. Among asphaltenes extracted from archeological bitumens, sulphoxide, sulphone and sulphate are the predominant oxidized forms of sulphur
