| 内蒙古正蓝旗钱家营子黑云母二长花岗岩锆石U-Pb年代学、Hf同位素特征及其地质意义 |
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| 关键词:Inner Mongolia Qianjiayingzi zircon SHRIMP U-Pb dating Hf isotope |
| 基金项目:中国地质调查局项目(编号: 1212010610421) |
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| Geochronology and Hf Isotopic Composition of the Biotite Monzogranite from the Qianjiayingzi Area in Zhenglan Banner of Inner Mongolia and Its Geological Implications |
| The Qianjiayingzi pluton is located in the Bainaimiao island arc belt to the north of Chifeng–Weichang–Baiyunebo fault. It is the most important part of the tectonic-magmatic belt on the southern margin of Xingmeng orogenic belt. Its formation age and genesis are of great significance for evaluating the tectonic setting and geological evolution in this orogenic belt. Based on 1:250000 regional geological survey, the authors investigated petrography and zircon U-Pb-Hf isotopic composition of Qianjiayingzi biotite monzogranite. The results show that the weighted average age of zircon 206Pb/238U is (247.2±4.7) Ma, indicating that the biotite monzogranite was formed in the late Early Triassic. The 176Hf/177Hf values of samples are 0.282 298~0.282 371, corresponding to the εHf(t) values of –8.7 ~ –11.4, and the tDM2 values of Hf isotopes are 1.64~1.74 Ga, suggesting that the parent magma of Qianjiayingzi biotite monzogranite may have been derived from the partial melting of the Paleoproterozoic old lower crust. Based on the geochronology and Hf isotopic characteristics of biotite monzogranite, it is considered that Qianjiayingzi area of Zhenglan Banner in Inner Mongolia was in an extensional environment of post collision between Xingmeng orogenic belt and North China plate in Early Triassic. |
| LI Ya-dong,JIANG Xiao-jun,LIU Yong-qing,LI Chao,SUN Hui-yi,LU Lei.2021.Geochronology and Hf Isotopic Composition of the Biotite Monzogranite from the Qianjiayingzi Area in Zhenglan Banner of Inner Mongolia and Its Geological Implications[J].Acta Geoscientica Sinica,42(1):85-97. |
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