CARBON ISOTOPIC VARIATIONS OF KEROGEN PYROLYZATES

A method has been developed for isotopic analysis of pyrolyzates from temperature-programmed pyrolysis of small quantities of immature to early mature kerogen concentrates. A C//5// plus pyrolyzate is collected and oxidized on-line to carbon dioxide for stable carbon isotopic measurement. Results indicate that the carbon isotopic composition of the pyrolyzate varies with final pyrolysis temperature by up to 0. 7 ppt. Based on the limited pyrolyzate isotopic variation with temperature, this method is considered to have potential application to source-oil assignment problems. Correlation can be achieved via composite carbon isotopic profiling; the elegance of the method deriving from the comparison of a petroleum with the oil labile component of a candidate source kerogen assemblage.