Based on feild outcrop survey, lithology observation and systematic sampling, and with the scan-ning electron microscope, rock pyrolysis, biomarker compound test and analysis, this paper discussed source rock characteristics and paleoenvironment in western Hubei. The lithology at the bottom of Lower Siluri-an Longmaxi Formationn in this study area is mainly dark carbonaceous shale, the mineral composition is mostly clay minerals, quartz and feldspar, the content of illite and kaolinite is high, but also contains a minor amount of strawberry pyrite and graptolite fossils. The test and analysishow that the total organic carbon con-tent (TOC) of the source rock is 0.8–6.32％, the average value is 3.42％ , and the vitrinite reflectance (Ro) is 1.57–2.95％. The type of organic matter is mainly type Ⅱ2. The overall abundance of organic matter is high, and the degree of thermal evolution has reached the stage of high maturity and over maturity. All these have become the good material basis and conditions for the formation of shale gas. The paleoenvironment of the source rocks indicates that the organic matter is a mixed source of planktonic algae and bacteria material. The large amount of hopane also indicates that the bacterial activity is strong during the deposition of organic matter; The water of the ancient lake is almost freshwater and brackishwater in some parts; The redox proper-ty of the water is in a strong reduction environment and with a stable stratification, which is also conducive to the preservation of organic matter. The above research results will provide the application of shale gas explo-ration in western Hubei.

WANG Neng;DU Jiangfeng;LIU Rong;ZHANG Kun;YAN Xu;LIU Gaofei

College of Earth Sciences,Jilin University,Changchun 130061,China;CNOOC Research Institute Co.,Ltd.,Beijing 100028,China;School of Geographical Sciences,Northeast Normal University,Changchun 130024,China

世界地质（英文版）

[1]WANG Neng;DU Jiangfeng;LIU Rong;ZHANG Kun;YAN Xu;LIU Gaofei-.Characteristics of source rocks and paleoenvironment of Lower Silurian Longmaxi Formation in western Hubei)[J].世界地质（英文版）,2022(04):264-276

feild,Siluri,Formationn,graptolite,analysishow,hopane,brackishwater

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