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    华北北部中元古界洪水庄组物源和沉积环境分析

    Provenance and sedimentary environment of the Mesoproterozoic Honghongzhuang Formation in northern part of North China

    • 摘要: 为探讨华北地区中元古界洪水庄组黑色泥页岩物源和沉积环境,采集了燕辽地区清河剖面洪水庄组样品,进行元素地球化学测试和分析。结果表明:洪水庄组沉积物来源不仅有陆源碎屑物质,还有海水沉积物贡献。Y/Ho和ΣREE交会图版分析认为海水沉积物来源占比为10%~20%。此外,稀土元素分布模式以及Ce和Eu异常表明沉积物来源有火山热液活动的参与。Mo-EF/U-EF分析结果表明洪水庄为海洋非滞留海盆沉积环境,氧化还原条件在沉积期发生了演变:在洪一段沉积时期,水体还原程度强,为厌氧-硫化环境;洪二段沉积时期,水体还原程度降低,为贫氧-厌氧环境。分析认为洪水庄组物源组成和沉积环境演变与沉积构造背景密切相关。

       

      Abstract: In order to further explore the provenance and sedimentatary environment of mud shale in the Mesoproterozoic Hongshuizhuang Formation of northern China, samples were collected from outcrops of the Qinghe section of Honghongzhuang Formation for elementary geochemical testing and analysis. The results show that the sediments were not only from terrigenous clastics but also from marine sediments. The results of Y/Ho and ΣREE relationship diagram analysis show that the source proportion of seawater sediments is 10%-20%. In addition, the distribution pattern of rare earth elements and the Ce and Eu anomalies indicate the involvement of volcanic hydrothermal activity in the sediment source. Mo-EF/U-EF analysis results show that Hongshuizhuang is a sedimentary environment of Marine non-stationary basin, and the evolution of redox conditions in the sedimentary period is as follows:in the period of the Lower Member deposition of Hongshuizhuang Formation, the water body was in a strong reductive anaerobic-sulfurization environment; while, during the period of its Upper Member deposition, the reduction degree of water decreased and the environment was anaerobic. It is concluded that the provenance composition and sedimentary environment evolution of the Honghongzhuang Formation are closely related to the sedimentary tectonic setting.

       

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