彭光荣,石创,龙祖烈,等. 珠江口盆地恩平21洼文昌组泥岩元素地球化学特征及其与有机质富集的关系[J]. 海洋地质前沿,2023,39(6):65-74. DOI: 10.16028/j.1009-2722.2022.233
    引用本文: 彭光荣,石创,龙祖烈,等. 珠江口盆地恩平21洼文昌组泥岩元素地球化学特征及其与有机质富集的关系[J]. 海洋地质前沿,2023,39(6):65-74. DOI: 10.16028/j.1009-2722.2022.233
    PENG Guangrong, SHI Chuang, LONG Zulie, et al. Relationship between element geochemical characteristics and organic matter enrichment of Wenchang Formation mudstones in Enping Sub-sag 21, Pearl River Mouth Basin[J]. Marine Geology Frontiers, 2023, 39(6): 65-74. DOI: 10.16028/j.1009-2722.2022.233
    Citation: PENG Guangrong, SHI Chuang, LONG Zulie, et al. Relationship between element geochemical characteristics and organic matter enrichment of Wenchang Formation mudstones in Enping Sub-sag 21, Pearl River Mouth Basin[J]. Marine Geology Frontiers, 2023, 39(6): 65-74. DOI: 10.16028/j.1009-2722.2022.233

    珠江口盆地恩平21洼文昌组泥岩元素地球化学特征及其与有机质富集的关系

    Relationship between element geochemical characteristics and organic matter enrichment of Wenchang Formation mudstones in Enping Sub-sag 21, Pearl River Mouth Basin

    • 摘要: 泥岩的元素特征能够较好地保存于原始沉积记录。为了明确恩平21洼文昌组泥岩元素地球化学特征及其与有机质富集的关系,选择YJ-1井文昌组10个泥岩岩屑样品,开展有机碳、常量元素和微量元素测试。在分析常量、微量元素地球化学特征的基础上,利用元素地球化学方法,系统分析洼陷文昌期古气候、古水深、古氧相和古生产力等古环境指标。文昌组泥岩元素平均含量对UCC(Upper Continental Crust)做标准化处理,恩平21洼文昌组泥岩具有富集Al2O3、K2O和MnO,贫CaO、MgO和Na2O;富Li、Be、Zn、Rb、Cs、Ba、Pb、Th和U,贫Sr、V和Cr的特征。古环境指标显示恩平21洼文昌期气候属于温暖湿润-温热潮湿,湖泊水深相对较深,纵向水深变化小,水体分布稳定,水体以还原环境为主,古生产力相对较高,但纵向差异大。泥岩有机碳含量与古生产力参数相关性较差,而与水体还原性之间具有较好的正相关关系,表明有机质富集受控于水体的氧化还原程度,水体还原条件有利于有机质的保存,有机质富集属于“保存模式”。进一步分析显示,古气候条件是文昌组有机质富集的关键性因素,温热潮湿的气候对湖泊生产力有一定的积极影响,同时降水量较大,湖泊水体较深,有利于湖底还原环境的形成和保持,进而有利于有机质的保存。

       

      Abstract: The elements of mudstones can well preserve the original sedimentary records. To define the element geochemical characteristics of the Wenchang Formation mudstones in Enping Subsag 21 and its relationship with enrichment of organic matter, 10 debris samples of the mudstones from well YJ-1 were collected, on which geochemical tests of organic carbon, major elements and trace elements were conducted. The geochemical characteristics of major and trace elements were examined, and paleo-environmental indicators such as paleo-climate, paleo-water depth, paleo-oxygenation facies, and paleo-productivity of the Wenchang Formation in the subsag were systematically analyzed. Compared with the content of major and trace elements in the Upper Continental Crust (UCC), major elements of the Wenchang Formation mudstones in Enping Subsag 21 are relatively enriched in Al2O3, K2O, and MnO, and poor in CaO, MgO, and Na2O. Trace elements are rich in Li, Be, Zn, Rb, CS, Ba, Pb, Th, U, and poor in Sr, V, and Cr. Paleoenvironmental indicators show that climate of Enping Subsag 21 in the Wenchang period was warm-moist to warm-humid. The paleo-lake was relatively deep and stable. Redox environment of the lake was mainly sub-reductive. Paleo-productivity of the lake was relatively high, and the vertical difference was significant. Correlation between organic carbon content of mudstones and paleo-productivity parameters is poor, but there is a good positive correlation with reducibility of the lake. Enrichment of organic matter was controlled by oxidation-reduction degree of the lake. Reduction condition of the lake was conducive to the preservation of organic matter. Enrichment of organic matter belongs to the "preservation mode". Further analysis shows that paleo-climate is the key factor for enrichment of organic matter in the Wenchang Formation. Warm and humid climate has a certain positive impact on productivity of the lake. Meanwhile, the precipitation was large, and the lake was deep, which was conducive to a reducing environment at the lake bottom, and thus conducive to the preservation of organic matter.

       

    /

    返回文章
    返回