新疆额尔宾山花岗岩侵位年龄和成因及其对南天山洋闭合时代的限定

发布时间：2017-12-27 11:21

本文关键词：新疆额尔宾山花岗岩侵位年龄和成因及其对南天山洋闭合时代的限定　出处：《地质通报》2016年01期 　论文类型：期刊论文

【摘要】：额尔宾山花岗岩岩体位于南天山晚古生代侵入岩带,对该花岗岩进行锆石U-Pb定年获得296.1±1.8Ma的年龄,为早二叠世。岩石主量元素分析结果表明,该花岗岩的Si O2含量为66.96%~67.3%,富碱(Na2O+K2O=7.53%~7.97%),K2O/Na2O1(1.15~1.27),属高钾钙碱性系列岩石;Al2O3为15.56%~15.62%,Al2O3K2O+Na2O+Ca O,属于过铝型。岩石稀土元素配分模式呈现轻稀土元素(LREE)富集((La/Yb)N=27.03~30.62)、重稀土元素(HREE)亏损((LREE/HREE)=18.2~20.1)、具有中等程度的负Eu异常(δEu=0.64~0.68)。微量元素判别结果显示,其具有I-A型花岗岩过渡的特征。结合区域地质背景综合分析,初步认定该岩体可能形成于南天山同碰撞向后碰撞构造体制转换时期,据此可以推测南天山洋盆闭合时限至少应该在早二叠世以前。
[Abstract]:Eerbin mountain granite pluton is located in the southern Tianshan late Paleozoic intrusive rocks, zircon U-Pb dating 296.1 + 1.8Ma age of the granite in the early permian. The main element analysis results show that the Si O2 content of the granite is 66.96%~67.3%, alkali rich (Na2O+K2O=7.53%~7.97%), K2O/Na2O1 (1.15~1.27), belongs to high potassium calc alkaline series rocks; Al2O3 15.56%~15.62%, Al2O3K2O+Na2O+Ca O, belongs to aluminum. The REE distribution pattern of rocks is characterized by enrichment of light rare earth elements (LREE) ((La/Yb) N=27.03~30.62), loss of heavy rare earth elements (HREE) ((LREE/HREE) =18.2~20.1), and a moderate negative Eu anomaly (delta Eu=0.64~0.68). The result of trace element discrimination shows that it has the characteristics of the transition of I-A type granite. With the comprehensive analysis of regional geological background, initially determined that the rock mass may be in the southern Tianshan Mountains with the collision to post collision tectonic transition period, thus can speculate the South Tianshan oceanic basin in the early Permian period should be closed at least before.
【作者单位】：中国地质科学院地质研究所大陆构造与动力学国家重点实验室同位素热年代学实验室;昆明理工大学;
【基金】：国家自然科学基金项目(批准号:41473053) 中国地质调查局项目(编号:12120113015600、1212011120293) 公益性行业专项经费(编号:201211074-05、200911043-13)
【分类号】：P534.46;P588.12
【正文快照】： YU Shun1,YANG Jing1,YUAN Xia11.中国地质科学院地质研究所,大陆构造与动力学国家重点实验室,同位素热年代学实验室,北京100037;2.昆明理工大学,云南昆明6500931.State Key Laboratory of Continental Tectonics and Dynamics,Institute of Geology,Chinese Academy of Geolo

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