Effects of transgression on aromatic hydrocarbon composition characteristics:a case study of mesozoic humic coal in the Kuqa Depression

Aromatic compounds are important organic components in source rocks and crude oil, which are rich in geochemical information, and they has been wild used in the study of sedimentary environment and maturity, while the influence of sedimentary environment on the distribution characteristics of humic coal aromatic compounds is rare studied.There are obvious differences in aromatic compound content and distribution characteristics of the humic coal samples from the Kuqa River profile of the Kuqa depression and the Kapushaliang River profile in this study.The Kuqa River profile contains high-abundance naphthalene, phenanthrene series compounds and high content of diabenzofuran and alkay diabenzofuran, rich in retene, cadalene, 1, 2, 5-TMN and 1, 2, 5, 6-TeMN and other higher plant source compounds, which belong to the characteristics of typical oxidation environment swamp phase humic coal.Different from the aromatic distribution of traditional humic coal, the mass spectrometry-chromatography results of humic coal in the Kapushaliang River profile show that it had higher content of phenanthrene series, 9-methylphenanthrene, diabenzothiophene, alkay diabenzothiophene and other compounds that characterized the reduced environment and the input of homonemeae.The research results show that the difference may be due to the biological transformation of higher plants dominated by bacteria and other microorganisms caused by seawater intrusion during the sedimentary diagenesis of the Kapusaliang River section.