| 东昆仑西段阿确墩地区晚古生代花岗岩成因、锆石U-Pb年龄及其地质意义 |
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| 引用本文： | 李猛,胡朝斌,查显锋,高晓峰,李婷,姚志亮.东昆仑西段阿确墩地区晚古生代花岗岩成因、锆石U-Pb年龄及其地质意义[J].地球科学,2020,45(7):2598-2609. |
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| 作者姓名： | 李猛 胡朝斌 查显锋 高晓峰 李婷 姚志亮 |
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| 作者单位： | 1.中国地质调查局西安地质调查中心造山带地质研究中心, 陕西西安 710054 |
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| 基金项目： | 国家自然科学基金项目41602005中国地质调查局项目DD2016002中国地质调查局项目DD20190065 |
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| 摘 要： | 东昆仑西段阿确墩地区晚古生代花岗质岩体，主要分布在豹子沟一带，呈岩基状产出.岩石地球化学研究显示，其具有钙碱性、弱过铝质（A/CNK=0.99~1.04）特征；稀土元素球粒陨石标准化表现为轻稀土富集，重稀土亏损的特征，具弱负Eu异常，δEu为0.73~0.97；微量元素显示高场强元素Nb、Ta、Ti等亏损的特征，认为其形成于陆缘弧环境，属于I型花岗岩.运用LA-ICP-MS技术对该花岗质岩体进行锆石U-Pb测年，获得二长花岗岩年龄为281.5±4.0 Ma，表明其形成于早二叠世晚期.结合区域构造演化，表明特提斯洋于早二叠世晚期就已经开始向塔里木板块俯冲，该数据代表了目前已知最早的一期晚古生代-早中生代花岗岩浆活动时间，而此时的古特提斯洋处于伸展结束-俯冲开始转变时期.
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| 关 键 词： | 东昆仑造山带 二长花岗岩 地球化学 锆石U-Pb定年 古特提斯洋 |
| 收稿时间： | 2020-06-19 |
Genesis,Zircon U-Pb Geochronology and Geological Significance of Late Paleozoic Granite in Aquedun,West of East Kunlun Mountains |
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| Abstract: | The Late Paleozoic granitic rocks, which is batholith-like, in Aquedun, the west of East Kunlun mountains are mainly distributed in the area of Baozigou. The geochemical characteristics showed that it has calc-alkaline and weak peraluminous (A/CNK=0.99-1.04).The standardized distribution of chondrites of rare earth elements is steep on the left and slow on the right with negative Eu anomaly(δEu=0.73-0.97). Trace elements show losses of high-field strength elements such as Nb, Ta and Ti, which are believed to be formed in the continental margin arc environment and belong to the I-type granite. By the technique of LA-ICP-MS, zircon U-Pb dating of the granitic rock shows that the age of the monzonitic granite is 281.5±4.0 Ma. It is believed that the granite formed in the late of Early Permian. Combined with the regional tectonic evolution, it shows that the Paleotethys ocean began to subducting to the Tarim plate in the late of Early Permian, which may represent the earliest time of subduction, and the Paleotethys ocean was at the end of extension and the beginning of subduction transition. |
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