三峡地区埃迪卡拉系至下寒武统地层中硒的含量分布富集规律

发布时间：2018-10-13 18:23

【摘要】：分析了三峡地区埃迪卡拉系至下寒武统(E-ε_1)地层中硒(Se)的含量分布富集规律,探讨了Se的显著和非显著富集层的元素地球化学特征.结果表明,Se为E-ε_1地层中最富集(浓集)的元素,其富集系数EF(与上地壳平均元素含量相比)和浓集系数CC(与同类岩性相比)均值分别为26.97和48.04.富集系数EF′(Al标准化之后的EF)指示.Se为第二富集的元素(Se~(EF′)=218.73),低于Cd(Cd~(EF′)=288.46),远高于第三富集的微量元素As(As~(EF′)=97.49).Se在E-ε_1地层中含量范围为10.5~30.08ppm,算数均值为1.35ppm.相对于南沱组(Se~(EF)=2.29),E-ε_1地层中Se~(EF)值增加11.78倍.其EF均值呈现为水井沱组(92.58)岩家河组(54.45)陡山沱组(24.72)灯影组(2.48)石牌组(1.95)天河板组下部(1.24).E-ε_1地层中Se的含量较服从自然对数正态分布,表现出正偏态分布类型.Se显著富集(EF10)的层位主要包括陡II下部、陡II上部、陡III顶部、陡IV、岩家河组底部和上部、水井沱组下部和上部.元素地球化学特征表明:Se显著富集层中Se含量普遍受陆源碎屑的影响,还受热液、火山碎屑、深部物源等单一或多因素的共同作用.此外,黄铁矿对部分层位(陡II上部、陡IV和水井沱组上部)及有机质对部分层位(陡II下部和水井沱组上部)中Se的富集具有促进作用.Se的非显著富集层(除陡I、水井沱组中部、石牌组和天河板组下部外)中Se含量仍受陆源碎屑影响,而其他的因素(热液、火山碎屑和深部物源等)的活动普遍较弱.
[Abstract]:The distribution and enrichment of selenium and (Se) in the Edikala and Lower Cambrian (E- 蔚 _ 1) strata in the three Gorges area are analyzed, and the geochemical characteristics of the significant and non-significant enrichment layers of Se are discussed. The results show that Se is the most enriched (concentrated) element in E- 蔚 _ 1 formation, and the mean values of EF (compared with the average element content of upper crust) and CC (compared with similar lithology) are 26.97 and 48.04, respectively. The enrichment coefficient EF' (EF after Al standardization) indicates that Se is the second enriched element (Se~ (EF') = 218.73), lower than Cd (Cd~ (EF') = 288.46), and far higher than that of the third enriched trace element As (As~ (EF') = 97.49). Se) in the E- 蔚 _ 1 formation with a range of 10.530.08 ppm and a mean value of 1.35 ppm. Compared with the Nantuo formation (Se~ (EF) = 2.29), the Se~ (EF) value in the E- 蔚 _ 1 formation increases 11.78 times. The EF mean value is that the content of Se in the Jingtuo formation (92.58), the Yanjiahe formation (54.45), the Doushantuo formation (24.72), the Dengying formation (2.48), the Shipai formation (1.95), the lower part of the Tianheban formation (1.24). The content of Se in the E- 蔚 _ 1 formation is more normal than that in natural logarithmic normal distribution. The layers of Se significant enrichment (EF10) mainly include the lower part of steep II, the upper part of steep II, the top of steep III, the bottom and upper part of Yanjiahe formation of steep IV, and the lower and upper part of Shuituo formation. The geochemical characteristics of elements indicate that the content of Se in the significant enrichment layer of Se is generally affected by continental clasts, and also by single or multiple factors, such as hydrothermal solution, volcanic clastic, deep provenance and so on. In addition, pyrite is opposite to part of the horizon (steep II upper, The enrichment of Se in some layers (the lower part of steep II and the upper part of Shuituo formation) is promoted by organic matter and the upper part of steep IV and Shuituo formation. The Se content in the lower part of Shipai formation and Tianheban formation is still affected by continental clastic, while the activity of other factors (hydrothermal, pyroclastic and deep provenance, etc.) is generally weak.
【作者单位】：中国科学院地理科学与资源研究所;中国科学院大学资源与环境学院;
【基金】：国家自然科学基金项目(批准号:41172310,41472322) 国家重点基础研究发展计划项目(编号:2014CB238906)资助
【分类号】：P534;P595

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