内蒙古西部额济纳旗及邻区二叠纪暗色泥岩微量元素和稀土元素地球化学特征  

Rare Earth and Trace Elements Geochemical Characteristics of the Dark Permian Mudstones in Ejinaqi and Its Surrounding Areas, Western Inner Mongolia

作　　者：宋健[1] 赵省民[1] 陈登超[2] 邓坚[1] 苗忠英[1] 明承栋[3] 陆程[1] 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037 [2]中国石化胜利油田地质勘探院,山东东营257015 [3]中国地质大学(北京),北京100083

出　　处：《地质学报》2012年第11期1773-1780,共8页Acta Geologica Sinica

基　　金：中国地质调查局"天山-兴蒙构造带石炭-二叠系对比研究"项目(编号1212011120966)资助成果

摘　　要：对泥岩微量元素系统分析表明,额济纳旗及邻区二叠纪整体为半咸水环境;纵向上,二叠纪水体盐度逐渐降低,海水逐渐淡化的过程与裂谷盆地演化消亡的过程同步;横向上,东部(雅干以东)古盐度明显高于西部(北山地区),这与区内水体东深西浅的沉积古地理格局有关,与古生物分布特征反映的古盐度一致。综合泥岩V/V+Ni、Ceanom分析,认为区内二叠纪整体为缺氧、还原环境,该环境有利于有机质保存。综合泥岩稀土元素配分模式及野外地质调查资料分析表明,区内泥岩的原始物质应来自上地壳,其母岩可能为花岗岩和粘土岩的混合成因。The analysis of trace elements of the dark Permian mudstones shows that Ejinaqi and its surrounding areas were semi-salt water sedimentary environment during the Permian. Vertically, the water salinity was gradually reduced, and this process was synchronous with the extinctive process of the rift basin. Horizontally, salinity in the east （to east of the Yagan area） was obviously higher than that in the west （Beishan area）, which was probably related to paleo-geographical sedimentary pattern （deep water in the east and shallow in the west）, and was consistent with the distribution characteristics of paleontology. Combined with the analysis of V/V＋ Ni and Ce of mudstones, it is suggested that Permian period was characteristic of reductive environment and was helpful to the preservation of organic matters. Combination of distributive pattern of the rare earth elements from dark mudstones with field geological survey indicates that its province was from the upper crust and its parent rocks were the mixing of claystones and granite rocks in the studied area.

关 键 词：泥岩 微量元素 稀土元素 古盐度 还原环境 母岩 二叠纪 内蒙古 

分 类 号：P595[天文地球—地球化学]