史冀忠, 崔海峰, 许伟, 宋博, 王宝文. 银额盆地巴隆乌拉白垩系巴音戈壁组黑色页岩沉积环境及有机质富集模式[J]. 地质通报, 2022, 41(8): 1430-1444. DOI: 10.12097/j.issn.1671-2552.2022.08.010
    引用本文: 史冀忠, 崔海峰, 许伟, 宋博, 王宝文. 银额盆地巴隆乌拉白垩系巴音戈壁组黑色页岩沉积环境及有机质富集模式[J]. 地质通报, 2022, 41(8): 1430-1444. DOI: 10.12097/j.issn.1671-2552.2022.08.010
    SHI Jizhong, CUI Haifeng, XU Wei, SONG Bo, WANG Baowen. Sedimentary environment and organic matter enrichment model of black shale from Cretaceous Bayingebi Formation in Balongwula, Yingen-Ejin Banner Basin[J]. Geological Bulletin of China, 2022, 41(8): 1430-1444. DOI: 10.12097/j.issn.1671-2552.2022.08.010
    Citation: SHI Jizhong, CUI Haifeng, XU Wei, SONG Bo, WANG Baowen. Sedimentary environment and organic matter enrichment model of black shale from Cretaceous Bayingebi Formation in Balongwula, Yingen-Ejin Banner Basin[J]. Geological Bulletin of China, 2022, 41(8): 1430-1444. DOI: 10.12097/j.issn.1671-2552.2022.08.010

    银额盆地巴隆乌拉白垩系巴音戈壁组黑色页岩沉积环境及有机质富集模式

    Sedimentary environment and organic matter enrichment model of black shale from Cretaceous Bayingebi Formation in Balongwula, Yingen-Ejin Banner Basin

    • 摘要: 银额盆地早白垩世沉积的巴音戈壁组湖相页岩是一套重要的烃源岩。通过对巴隆乌拉剖面黑色页岩进行地球化学分析,研究其主量、微量和稀土元素特征,以及黑色页岩沉积的古环境及有机质富集模式。结果表明,Sr/Ba值为0.14~0.24,平均值为0.18,B/Ga值为3.89~6.51,平均值为5.03,相当B含量为230.88×10-6~375.99×10-6,平均值为294.95×10-6,古盐度为11.97‰~15.83‰,平均值为14.70‰;V/(V+Ni)值为0.67~0.84,平均值为0.74,Ceanom值为-0.113~0.018,平均值为-0.055;古气候指数(C)为0.80~1.34,平均值为1.06,化学蚀变指数(CIA)为75~81,平均值为79;古水深为4.16~88.04 m,平均值为33.40 m;P/Ti值为0.10~0.22,平均值为0.15,过剩钡(BaXS)为-46.5×10-6~144.5×10-6,平均值为38.85×10-6。综合各参数特征,研究区黑色页岩沉积于温暖、湿润、半咸水、缺氧的还原环境,沉积水体较深,具有低的古生产力条件。有机碳含量与沉积环境间相关性的研究表明,巴音戈壁组黑色页岩有机质富集是古盐度、氧化-还原条件、古气候、古生产力等因素共同作用的结果。研究结果可为银额盆地中生界沉积演化和油气资源评价提供理论支撑。

       

      Abstract: The lacustrine shale of Early Cretaceous Bayingebi Formation is a suite of important source rocks resources in the Yingen-Ejin Banner basin.We studied the characteristics of the major elements, trace elements and rare earth elements, and the paleoenvironment and organic matter enrichment model of the black shale by the geochemical analysis of the Balongwula section.The results show that Sr/Ba value is 0.14~0.24, average value is 0.18, B/Ga value is 3.89~6.51, average value is 5.03, equivalent boron content is 230.88×10-6~375.99×10-6, average value is 294.95×10 -6, paleosalinity is 11.97‰~15.83‰, average value is 14.70‰; V/(V+Ni) value is 0.67~0.84, average value is 0.74, the Ceanom value is -0.113~0.018, average value is -0.055; the paleoclimate index(C) is 0.80~1.34, average value is 1.06, the chemical index alteration(CIA) is 75~81, average value is 79; the ancient water depth is 4.16~88.04 m, average value is 33.40 m; P/Ti value is 0.10~0.22, average value is 0.15, the excess barium(BaXS) is -46.5×10-6~144.5×10-6, average value is 38.85×10-6.Based on the characteristics of various parameters, the black shale in the study area is deposited in a warm and humid climate, with a sedimentary environment of deep lacustrine facies under an brackish water and anoxic condition.The paleoproductivity reflect a low initial paleoproductivity.The study on the correlation between organic carbon content and sedimentary environment shows that the organic matter enrichment in black shale of Bayingebi Formation is the result of the combined action of paleosalinity, oxidation-reduction conditions, paleoclimate and paleo-productivity.This will provide theoretical support for the sedimentary evolution of Mesozoic and the evaluation of oil and gas resources in Yingen-Ejin Banner Basin.

       

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