| At present, large sets of middle-lower Jurassic oil shales have been discovered in the Xichangliang, Changshe mountain and Shengli River areas of the North Qiangtang Basin, and the differences of geochemical characteristics and controlling factors of these oil shales have not been clarified. The present study employed total organic carbon analysis, extraction and separation techniques, as well as gas chromatography-mass spectrometry, to investigate the abundance, composition, maturity of organic matter, and geochemical characteristics of saturated hydrocarbons and aromatic compounds in oil shale samples collected from Xichangliang, Changshe mountain, and Shengli River areas. The results show that there are some differences in the distribution of plant ratio, gammarecane index, fluorene series compounds, alkyl dibenzothiophene series compounds, alkyl dibenzofuran series compounds, indicating that the sedimentary environment of oil shale in Shengli River area has the highest reduction and highest salinity, followed by Xichangliang oil shale, and Changshe mountain oil shale has the weakest reduction and lowest salinity. According to the distribution characteristics of tricyclic terpenes and regular steranes and the steroidal medium ratio, the organic matter sources of oil shale in Shengli River area are mainly lower aquatic organisms, the organic matter sources of oil shale in Xichangliang area are mainly lower aquatic organisms and have mixed sources, and the organic matter sources of oil shale in Changshe mountain area are mainly mixed sources. Using steranes, alkyl naphthalene, alkyl phenanthrene and other maturity parameters, it is found that the oil shale in the Xichangliang area has reached the low maturity stage, and the oil page in Shengli River and Changshe mountain area has reached the mature to high maturity stage. Comprehensive analysis shows that oil shale in Shengli River area has the greatest potential for oil generation and is the main target of future exploration. |