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四川盆地上奥陶统五峰组-下志留统龙马溪组页岩中蕴藏着丰富的页岩气资源，是我国页岩气勘探开发的重点层系。由于该时期构造运动活跃，古气候、古环境变化较大，导致优质页岩纵横向展布和物性特征均表现出强烈的非均质性，从而对页岩气勘探造成极大影响。为进一步明确页岩古沉积环境与有机质富集主控因素，本文以长宁双河、重庆漆辽和巫溪田坝三个典型剖面为研究对象，综合薄片鉴定、扫描电镜、全岩矿物、主、微量元素、有机碳同位素、黄铁矿硫同位素等方法，共开展1092样次实验分析，深入研究了页岩岩石学、地球化学等特征及其指示意义。研究表明，四川盆地五峰组-龙马溪组页岩主要包括黏土矿物、石英、白云石、方解石、斜长石、钾长石、黄铁矿等矿物，其中五峰组和龙马溪组发育硅质和钙质富有机质笔石页岩，而观音桥层为生物碎屑泥灰岩；页岩中还发育了大量的草莓状黄铁矿，黄铁矿粒径主要介于5.00~10 .00μm之间，并发现大量放射虫化石；纵向上龙马溪组TOC含量最高，其次是五峰组，观音桥层TOC含量最低，平面上川东地区TOC含量最高，品质最好，而川南和川东北地区TOC含量相近，品质相似；页岩中主量元素SiO2含量最高，其次是CaO和Al2O3；页岩中微量元素主要包括Rb、Ba等大离子亲石元素，Zr、Hf、Th、U等高场强元素，以及稀土元素等，且分布特征相似，与北美页岩具有可对比性；页岩中REE球粒陨石标准化配分模式图相似，表现出Eu中等负异常特征；垂向上观音桥层δ13Corg最重，平面上川东地区δ13Corg最轻；页岩中δ34Spy分布特征为观音桥层＞龙马溪组＞五峰组。五峰组-龙马溪组页岩中硅质的来源基本不受热液影响，而主要来源于陆源碎屑，其次为硅质生物，为正常海相成因硅质岩。研究认为，硅质生物和火山活动可能是造成五峰组-龙马溪组页岩中硅质含量差异的重要原因，且五峰组-龙马溪组硅质页岩主要形成于大陆边缘沉积环境。通过对五峰组-龙马溪组火山灰研究表明，斑脱岩特征相似，为钾质斑脱岩，原岩构造环境主要为岛弧环境，且火山灰物质来源相似，可能来自北部秦岭地区。此外，火山灰对海洋表层初级生产力的提高具有重要的意义，为富有机质页岩形成提供了物质基础。从五峰组早期到龙马溪组中期，四川盆地可划分为5个沉积阶段，且经历了从贫氧→缺氧→富氧→缺氧→贫氧的演化过程，具体为龙马溪组早期和五峰组晚期水体缺氧，龙马溪组中期和五峰组早-中期水体贫氧，而观音桥层时期水体富氧。综合古沉积环境、古生产力、陆源碎屑输入等影响因素，研究认为缺氧沉积环境有利于有机质富集和保存，但有机质富集同时也受陆源碎屑和古生产力等因素影响。总之，缺氧的保存条件、良好的物质基础、适宜的气候条件、适当的沉积速率、稳定的构造背景等因素时空耦合关系决定了页岩中有机质的丰度，从而建立了五峰组-龙马溪组页岩沉积模式。 研究成果对四川盆地页岩气的勘探与开发将提供理论指导，并有助于提高四川盆地页岩气勘探开发效率，推动中国页岩气工业快速发展。

Shale from Wufeng Formation of upper Ordovician - Longmaxi Formation of lower Silurian in Sichuan Basin contains abundant shale gas resources, which is the most important strata of shale gas exploration and development of China. Due to the active tectonic movement in this period, the paleoclimate and paleoenvironment changed greatly, resulting in the strong heterogeneity of the distribution and physical characteristics of shale in the vertical and horizontal direction, which had a great impact on shale gas exploration. For further studying the sedimentary environment and main control factors of organic matter enrichment, this paper has taken the Changning, Qiliao and Tianba three typical sections as the example, and has carried out 1092 samples analysis such as thin section identification, scanning electron microscopy, whole rock mineral, major and trace elements, organic carbon isotope, pyrite sulfur isotope, to study the characteristics of shale petrology and geochemistry. Results showed that the shale from Wufeng - Longmaxi Formation was composed of clay minerals, quartz, calcite, dolomite, potassium feldspar, plagioclase, pyrite and other minerals. The Wufeng and Longmaxi formations developed siliceous and calcareous shale riching in organic matter and graptolites, whereas the Guanyinqiao Bed developed marlstone riching in biodetritus. In addition, a lot of framboidal pyrites and radiolaria fossils were found in the shale, and the grain size of framboidal pyrites was mainly between 5.00~10.00 μm. Vertically, Longmaxi Formation had the highest TOC content, followed by Wufeng Formation, and Guanyinqiao Bed had the lowest TOC content. On the plane, eastern of Sichuan Basin had the highest TOC content and the best quality, while southern and northeastern of Sichuan Basin had similar TOC content and quality. The SiO2 content of major element in shale was the highest, followed by CaO and Al2O3. Trace elements in the shale mainly included Rb, Ba and other large ion lithophilic elements, Zr, Hf, Th, U and other high field strength elements, as well as rare earth elements, etc., and their distribution characteristics were similar, which were comparable with the north American shale. Furthermore, chondrite–normalized REE patterns were similar and characterized by medium negative Eu anomalies. In the vertical direction, the δ13Corg was the heaviest in the Guanyinqiao Bed, and the δ13Corg was the lightest in the eastern of Sichuan Basin. The δ34Spy of shale was characterized by Guanyinqiao Bed＞Longmaxi Formation＞Wufeng Formation.The bedded chert from Wufeng and Longmaxi formations originated mainly from terrigenous input and siliceous organisms, and suffered slightly influence in hydrothermal fluid, revealing normal marine deposits. Besides, siliceous organisms and volcanic activities were the key factors controlling the differences in the SiO2 content of the bedded chert between Wufeng and Longmaxi formations, and the shale deposited in a continental margin environment. The study on the volcanic ash from Wufeng - Longmaxi Formation showed that the bentonites had similar characteristics with the same material sources and coincided with the K-bentonite. Furthermore, the tectonic environment of original rock mainly was the island arc environment and the volcanic ash might mainly come from north Qinling Mountains. Besides, the volcanic ash could improve the ocean surface primary productivity and provide material basis for the organic-rich shale.Studies suggested that the Sichuan Basin could be divided into five sedimentary stages and experienced an evolutionary process from dysoxic, anoxic, oxic, anoxic, dysoxic between early Wufeng Formation and middle Longmaxi Formation. In the early Longmaxi Formation and late Wufeng Formation, the water was anoxic, and the water was dysoxic in the middle Longmaxi Formation and early-middle Wufeng Formation, but the water was oxic in the Guanyinqiao Bed. Based on the comprehensive analysis of the factors affecting the paleosedimentary environment, paleoproductivity and the input of terrigenous detritus, the study showed that the anoxic sedimentary environment was conducive to the accumulation of organic matter, but it was also affected by the factors such as terrigenous detritus and paleoproductivity. To conclude, the spatio-temporal coupling relationship of factors such as anoxic preservation conditions, good material basis, suitable climatic conditions, appropriate deposition rate and stable tectonic background determined the abundance of organic matter in shale, thus establishing the sedimentary model of organic-rich shale.The research results will provide theoretical guidance and help improve the efficiency for the shale gas exploration and development in Sichuan Basin, and promote the rapid development of China's shale gas industry.