Abstract
Kerogens in sediments of different burial depth over a stratigraphic sequence in Neogene Shinjo sedimentary basin were heated from room temperature to 800℃ under a helium flow by a thermogravimetric analyzer (TG). Compounds released by the thermal decomposition of kerogen were introduced into and analyzed by a gas chromatograph-mass spectrometer (GC/MS). Two hundred and forty-nine compounds were identified and are mainly aliphatic and aromatic hydrocarbons. A release profile of each compound from kerogen with increasing heating temperature was obtained by TG-MS. In general, thermal release of compounds started around 350℃ which shifted to 450℃ with increasing burial depth of kerogen and ended roughly at 550℃. The release-peak width tended to become narrower with increasing burial depth of kerogen, which reflects the loss of a thermally more labile fraction of kerogen in sediments during diagenesis.
