内蒙古乌达地区上古生界不同沉积环境煤系烃源岩分子地球化学特征及意义

内蒙古乌达地区上古生界煤系烃源岩主要在海陆过渡相和陆相沉积环境的控制下沉积而成。精选出五种沉积环境下形成的煤系烃源岩样品,深入研究其分子地球化学特征。研究表明,泛滥平原形成的烃源岩以高氧芴、高姥鲛烷、高C29规则甾烷、高C19三环萜烷和高C24四环萜烷为主要特征;河控三角洲除氧芴含量稍低,具有和泛滥平原沉积环境相似的地化特征;潮坪和泻湖相的烃源岩中伽马蜡烷、植烷含量均较高,C26+三环萜烷丰度相对较高,三环萜烷绝对浓度大,规则甾烷以C27占优势,硫芴含量相对较丰富;潮控三角洲除Pr/Ph较高外,其余生物标志物特征与潮坪、泻湖环境下的烃源岩相似。

Molecular Geochemical Characteristics and Geological Significance of Upper Paleozoic Coal-measure Source Rocks from Different Sedimentary Environments of Wuda Region in Inner Mongolia

Upper paleozoic coal-measure source rocks of Wuda region in Inner Mongolia mainly deposited in transitionalSfaciesSand continental sedimentary environment. Coal-measure source rock samples have been selected from Five sedimentary environment, and have been conducted further study on their molecular geochemical characteristics. Research shows that, the source rocks from the food plain are characterized by high abandance of dibenzofuran, pristane, C₂₉ regular steranes, C₁₉ tricyclic terpane and C₂₄ tetracyclic terpane. River-dominated delta have the same geochemical characteristics with the flood plain, in addition to dibenzofuran slightly lower. ByScontrast,the source rocks from tidal flat and lagoon environments have high abandance of gammacerane, phytane,C₂₆₊ tricyclic terpane, and the tricyclic terpane concentration more bigger, with a predominance of C₂₉ regular sterane, the dibenzothiophene is relatively rich. Source rocks from tidal delta have the similar characteristics with tidal flat and lagoon except Pr/Ph is more higher.