Abstract
—The composition of the organic matter (OM) of coals of the Ulug-Khem Basin has been studied. According to Rock-Eval pyrolysis data, this OM is a type III kerogen, sometimes significantly oxidized. The coal of low-grade metamorphism has a high hydrocarbon potential. Based on the gas–liquid chromatography and chromatography–mass spectrometry data on the distribution of n-alkanes, isoprenoids, polycyclic biomarkers, and aromatic hydrocarbons, we have established the composition of the primary OM of the coals and the grade of OM metamorphism. The primary OM of the coals consists mainly of remains of aquatic vegetation and terrigenous OM. The latter includes conifer remains, which are identified from the presence of 4β(H)-19-norisopimarane in the aliphatic fraction of bitumen and from the domination of retene over cadalene and 6-isopropyl-1-isohexyl-2-methylnaphthalene in the aromatic fraction.