内蒙阿尔善布拉格一带早二叠世碱性花岗岩地球化学特征、锆石U-Pb年龄及其地质意义  

Geochemical Characteristics, Zircon U- Pb Age of the Early Permian Alkaline Granite and Its Geological Significance in the Aershanbulage,Innner Mongolia

作　　者：肖中军[1] 

机构地区：[1]河南省地质矿产勘查开发局第一地质矿产调查院,洛阳471000

出　　处：《地质调查与研究》2015年第3期171-181,191,共12页Geological Survey and Research

基　　金：中国地质调查"内蒙古1/5万浩宾塔拉幅;吉尔戈郎图幅;阿登锡勒大队幅;塔拉布拉格幅;朝勒更爱力幅;阿尔善布拉格幅区域地质矿产调查项目(1212011220452)"

摘　　要：通过对内蒙古苏尼特左旗阿尔善布拉格一带出露的碱性花岗岩的区域地质调查及综合研究测试,得到锆石U-Pb年龄为297±3 Ma^295.8±1.4 Ma。岩石中普遍含有霓石、钠闪石等碱性暗色矿物,具高硅、富碱,贫Fe Ot、Mg O特征,铝饱和指数A/CNK介于0.85~1.02之间。微量元素表现为富集Rb、Th、Zr、Hf等元素,亏损Ba、Nb、Sr、P、Ti,稀土配分曲线呈V型,属A型花岗岩,指示了贺根山洋闭合后的造山后伸展背景。The authors carry out some geochemical analysis on a alkaline granite pluton in the Aershanbulage, In- ner Mongolia. The age of this pluton is around 297±3 Ma-295.8± 1.4 Ma according to the U-Pb dating by LA.ICP-MS. Rock generally contains aegirine, riebeckite, such as alkaline dark minerals, and with high silicon, alkali rich, poor FeOt, MgO style characteristics. Aluminium saturation index A/CNK is between 0.85 - 1.02. Trace elements are rich in Rb, Th. Zr. Hf and depleted of Ba, Ti, Nb, Sr, R The LREE of these samples are highly differentiated, but the HREE present flat distributions. The element of Eu displays obvious negative anomaly with the δEu between 0.25 and 0.69. All the geochemical features above define this monzontic granite as the A- type granite, indicating the early Permian area has entered the post-tectonic tectonic environment.

关 键 词：阿尔善布拉格 碱性花岗岩 锆石U-PB年龄 A型花岗岩 

分 类 号：P588.121[天文地球—岩石学] P597[天文地球—地质学]