内蒙古西部额济纳旗及邻区上石炭统—下二叠统阿木山组火山岩的地球化学特征

分析了上石炭统小独山阶—下二叠统紫松阶阿木山组玄武岩地球化学特征，对玄武岩类型、岩石特征、构造环境等进行了探讨，结合前人的研究成果，阐述了石炭纪—二叠纪盆地的基本性质。Zr/TiO2-Nb/Y、SiO2-TFeO/MgO和Zr-Y-Nb图解显示，玄武岩类型主要为亚碱性的拉斑玄武岩；稀土元素球粒陨石配分模式为右倾曲线，(La/Yb）N值较高，轻重稀土元素分馏较强，(Gd/Lu）N值相对较低，重稀土元素分馏较弱，δEu在0.87~1.11之间，无明显Eu异常；N-MORB标准化的微量元素蛛网图显示，K2O、Rb、Ba、Th等不相容元素富集，Hf、Nb、Y等亏损。Zr-Zr/Y和Ta/Hf-Th/Hf构造环境图解表明，该玄武岩产于陆内裂谷，指示晚石炭世—早二叠世额济纳旗及其邻区已进入了陆内演化阶段，为拉张作用下的陆内裂谷（裂陷）盆地。

Geochemical characteristics of Carboniferous-Permian Amushan Formation volcanic rocks in Ejin Banner and its vicinities, western Inner Mongolia

Based on an analysis of basalt geochemical characteristics of Amushan Formation(western Ganquan Formation) of Upper Carboniferous Xiaodushan Stage-Lower Permian Zisong Stage and the basalt type,this paper deals with the rock characteristics and tectonic environment.Previous studies have already revealed the basic type of Carboniferous-Permian basin.The Zr/TiO2-Nb/Y,SiO2-TFeO/MgO and Zr-Y-Nb diagrams show that the basalt in Ejin Banner and its vicinities is mainly of the sub-alkaline tholeiite series.Chondri...