| 内蒙古因格井坳陷湖相白云质泥岩地球化学特征及地质意义 |
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| 引用本文： | 向龙,刘晓东,刘平辉,戴朝成.内蒙古因格井坳陷湖相白云质泥岩地球化学特征及地质意义[J].高校地质学报,2019,25(2):221. |
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| 作者姓名： | 向龙 刘晓东 刘平辉 戴朝成 |
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| 作者单位： | 东华理工大学地球科学学院核资源与环境国家重点实验室 |
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| 摘 要： | 本文对内蒙古巴音戈壁盆地因格井坳陷下白垩统音戈壁组上段湖相白云质泥岩进行了地球化学分析，据此探讨了其
对构造背景、源岩属性及古沉积环境重建的意义。研究表明：白云质泥岩具有富Ca，Na，Sr，U，V 元素，贫K，P，Ba，
Rb，Sc，Th，Zr 元素的特点；稀土元素总量变化范围大（59.29×10-6~283.80×10-6），轻、重稀土分异明显，δEu 为中等偏
强的负异常（平均值0.62），δCe 无异常（平均值1.01）。构造判别图解及δEu 异常特征共同指示白云质泥岩源岩具有大陆岛
弧和主动大陆边缘构造背景。稀土配分模式及源岩属性判别图解指示白云质泥岩源岩以上地壳长英质岩石为主。垂向上巴
音戈壁组上段整体为干旱、厌氧、偏强还原的咸湖环境。古气候、古盐度及氧化还原指标在巴音戈壁组上段中部和下部界
面变化明显。在下部（K1b2-1） 干热环境下出现过相对湿冷的沉积过程，古盐度、氧化还原环境也均与干热-冷湿演化具有
耦合性，即在厌氧的、偏强还原的咸湖沉积环境下存在短暂的氧化环境。
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| 关 键 词： | 白云质泥岩 地球化学 古地理环境 因格井坳陷 |
Geochemical Characteristics and Its Geological Significance of Lacustrine Dolomitic Mudstones in Yingejing Depression,Inner Mongolia |
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| XIANG Long,LIU Xiaodong,LIU Pinghui,DAI Chaocheng.Geochemical Characteristics and Its Geological Significance of Lacustrine Dolomitic Mudstones in Yingejing Depression,Inner Mongolia[J].Geological Journal of China Universities,2019,25(2):221. |
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| Authors: | XIANG Long LIU Xiaodong LIU Pinghui DAI Chaocheng |
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| Abstract: | Based on the geochemical analysis of lacustrine dolomitic mudstones in the upper Bayingebi Formation of the Lower
Cretaceous in Yingejing Depression, Bayingebi Basin， Inner Mongolia, its geological significance, source rock properties, and
paleo-depositional environment have been investigated. The results show that dolomitic mudstones are characterized by the enrichment
in Ca, Na, Sr, U, V and depletion in K, P, Ba, Rb, Sc, Th, Zr. The total REEs contents vary significantly (59.29×10-6~283.80×10-6) with
differentiation of LREE and HREE, which reveals a moderately strong negative Eu anomaly (average value 0.616) and Ce normality
(average value of 1.01). Tectonic discrimination diagrams and features of Eu jointly indicate that source rocks of dolomitic mudstones
were in a continental island arc and active continental margin setting. The pattern of REE distribution and diagrammatic diagramming
of source rocks suggests that dolomitic mudstones are mainly composed of felsic rocks from upper crustal feldspar rocks. Vertically,
upper Bayingebi Formation was deposited in a salty lacustrine environment with drought, anaerobic and strong partial reduction. And
paleoclimate, paleosalinity and redox index changed obviously in the middle and lower parts of upper Bayingebi Formation. Meanwhile,
a relatively wet-cold depositional process had appeared during the warm, dry environment of K1b2-1. The paleosalinity and redox
environment were also coupled with the evolution of warm-dry and cold-wet environment, that is, a brief oxic environment existed in
the anaerobic and strongly reduced, salty lacustrine environment. |
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| Keywords: | dolomitic mudstone geochemical paleogeography Yingejing depression |
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