| 内蒙古阿拉善地块东北缘狼山枕状玄武岩地球化学特征、锆石U-Pb年龄及构造背景 |
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| 引用本文： | 艾米尔丁&#;艾尔肯,解国爱,张进,曲军峰,田荣松,赵衡,李法浩,李甜.内蒙古阿拉善地块东北缘狼山枕状玄武岩地球化学特征、锆石U-Pb年龄及构造背景[J].地质通报,2019,38(5):810-823. |
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| 作者姓名： | 艾米尔丁&#;艾尔肯 解国爱 张进 曲军峰 田荣松 赵衡 李法浩 李甜 |
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| 作者单位： | 南京大学地球科学与工程学院, 江苏 南京 210046,南京大学地球科学与工程学院, 江苏 南京 210046,中国地质科学院地质研究所, 北京 100037,中国地质科学院地质研究所, 北京 100037,南京大学地球科学与工程学院, 江苏 南京 210046,中国地质科学院地质研究所, 北京 100037,南京大学地球科学与工程学院, 江苏 南京 210046,南京大学地球科学与工程学院, 江苏 南京 210046 |
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| 基金项目： | 国家重点研发计划项目《北方东部符合造山带岩石圈三维架构与成矿地质背景》（编号：2017YFC0601301）、《深部过程与成矿作用研究集成》（编号：2018YFC0603703）和南京大学“十三五”实验教学改革研究课题（编号：SY201913） |
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| 摘 要： | 狼山地区位于内蒙古阿拉善地块东北缘,其构造背景一直存在争议。报道狼山地区枕状玄武岩的锆石U-Pb年龄、地球化学研究成果。LA-ICP-MS锆石U-Pb定年结果表明,玄武岩中的锆石大多为捕获基底的锆石。根据锆石特征及侵入玄武岩的花岗岩年龄,得出玄武岩年龄为254～252Ma,属于二叠纪晚期。枕状玄武岩具有贫碱低钾的特征,亏损Nb、Ta、Ti、P,富集Rb、Ba、U等元素,富集轻稀土元素、亏损重稀土元素,具弱负Eu异常,显示岛弧玄武岩特征。初步认为玄武岩形成于活动大陆边缘弧环境,为古亚洲洋向南俯冲的产物,指示阿拉善地块北缘在二叠纪晚期为大陆边缘弧,为研究阿拉善地块东北缘晚古生代构造背景提供了证据。
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| 关 键 词： | 枕状玄武岩 狼山 LA-ICP-MS锆石U-Pb定年 地球化学 构造背景 |
| 收稿时间： | 2018/9/26 0:00:00 |
| 修稿时间： | 2019/1/2 0:00:00 |
Geochemistry, zircon U-Pb age and tectonic settings of pillow basalts in the Langshan area on the northern margin of the Alxa block, Inner Mongolia |
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| ARKIN Amirdin,XIE Guoai,ZHANG Jin,QU Junfeng,TIAN Rongsong,ZHAO Heng,LI Fahao and LI Tian.Geochemistry, zircon U-Pb age and tectonic settings of pillow basalts in the Langshan area on the northern margin of the Alxa block, Inner Mongolia[J].Geologcal Bulletin OF China,2019,38(5):810-823. |
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| Authors: | ARKIN Amirdin XIE Guoai ZHANG Jin QU Junfeng TIAN Rongsong ZHAO Heng LI Fahao and LI Tian |
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| Institution: | School of Earth Sciences and Engineering, Nanjing University, Nanjing 210046, Jiangsu, China,School of Earth Sciences and Engineering, Nanjing University, Nanjing 210046, Jiangsu, China,Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China,Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China,School of Earth Sciences and Engineering, Nanjing University, Nanjing 210046, Jiangsu, China,Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China,School of Earth Sciences and Engineering, Nanjing University, Nanjing 210046, Jiangsu, China and School of Earth Sciences and Engineering, Nanjing University, Nanjing 210046, Jiangsu, China |
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| Abstract: | The tectonic setting of the Langshan area, which is located on the northeastern margin of the Alxa block in Inner Mongolia, has always been controversial. This paper presents the results of zircon U-Pb geochronology and geochemical data of pillow basalts in the Langshan area. The basalt LA-ICP-MS zircon U-Pb dating results show that most zircons from basalts were captured from basement. Based on the features of zircon and the age of granite invading basalt, the age of basalt is estimated to be ca. 254~252Ma, which falls into the Late Permian. Pillow basalt shows the characteristics of island arc basalt with its low alkali and low potassium, depletion of Nb, Ta, Ti, P, enrichment of Rb, Ba, U, enrichment of LREE, and depletion of HREE with weak Eu negative anomaly. It is preliminarily believed that basalt was formed on the active continental margin and was produced by southward subduction of the ancient Asian Ocean. The results indicate that the northern margin of the Alxa block was a continental marginal arc in the Late Permian, thus providing evidence for the study of the Late Paleozoic tectonic setting on the northeastern margin of the Alxa block. |
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| Keywords: | pillow basalt Langshan LA-ICP-MS zircon U-Pb dating geochemistry tectonic setting |
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