| 羌北-昌都地块那益雄组火山岩锆石U-Pb年代学及地球化学特征 |
| |
| 引用本文： | 张锦,程鑫,高扬,李玉玉,朱亚林,周亚楠,吴汉宁.羌北-昌都地块那益雄组火山岩锆石U-Pb年代学及地球化学特征[J].岩石矿物学杂志,2019,38(1):77-89. |
| |
| 作者姓名： | 张锦 程鑫 高扬 李玉玉 朱亚林 周亚楠 吴汉宁 |
| |
| 作者单位： | 西北大学地质学系大陆动力学国家重点实验室;深圳市勘察测绘院有限公司 |
| |
| 基金项目： | 国家自然科学基金资助项目（41774073，41674070，41304049） |
| |
| 摘 要： | 本文对青藏高原羌北-昌都地块阿布日阿加措地区的晚二叠世那益雄组火山岩进行了年代学和地球化学研究。该火山岩主要由玄武岩、安山玄武岩、安山岩、流纹岩、凝灰岩组成,具有碱性玄武岩到酸性熔岩的特征。锆石U-Pb年代学研究表明该火山岩的形成时代为251. 1±4. 8～249. 6±1. 3 Ma之间。地球化学分析结果表明,该地区的流纹岩具有高的Si O2(74. 85%～77. 55%)和Na2O+K2O(5. 40%～6. 61%)含量,较低的MgO、K2O和Ca O含量,Al2O3含量低且稳定,里特曼指数平均为1. 15,小于3. 3。安山岩Si O2含量55. 13%～56. 28%,Na2O+K2O含量4. 13%～6. 15%,里特曼指数平均为2. 20,小于3. 3,属于钙碱性安山岩。碱性玄武岩Si O2含量51. 49%,Na2O+K2O含量6. 34%,里特曼指数为4. 73,属于碱性系列。稀土元素配分曲线为富集LREE的右倾型。另外,富集大离子亲石元素(LILE) Th、U,亏损高场强元素(HFSE) Nb、Ta等特征,均说明羌北-昌都地块阿布日阿加措地区的火山岩形成于陆缘岛弧环境。
|
| 关 键 词： | 昌都地块 晚二叠世 火山岩 年代学 地球化学 |
| 收稿时间： | 2018/6/10 0:00:00 |
| 修稿时间： | 2018/10/8 0:00:00 |
Geochemical characteristics and zircon U-Pb dating of Nayixiong Formation volcanic rocks from Northern Qiangtang-Qamdo landmass |
| |
| ZHANG Jin,CHENG Xin,GAO Yang,LI Yu-yu,ZHU Ya-lin,ZHOU Ya-nan and WU Han-ning.Geochemical characteristics and zircon U-Pb dating of Nayixiong Formation volcanic rocks from Northern Qiangtang-Qamdo landmass[J].Acta Petrologica Et Mineralogica,2019,38(1):77-89. |
| |
| Authors: | ZHANG Jin CHENG Xin GAO Yang LI Yu-yu ZHU Ya-lin ZHOU Ya-nan and WU Han-ning |
| |
| Institution: | State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi''an 710069, China;Shenzhen Geotechnical Investigation and Surveying Institute Co., Ltd., Shenzhen 518028, China,State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi''an 710069, China,State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi''an 710069, China,State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi''an 710069, China,State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi''an 710069, China,State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi''an 710069, China and State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi''an 710069, China |
| |
| Abstract: | Upper Permian Nayixiong Formation volcanic rocks from northern Qiangtang-Qamdo landmass of the Tibetan Plateau have many geochemical characteristics and zircon U-Pb dating data. The main volcanic rocks are basalt, andesite-basalt, andesite, rhyolite, tuff, which have the characteristics of alkaline basalt to acidic rhyolite. The result of the geochronologic study of zircon U-Pb dating data shows that the volcanic eruption ages vary from 251.1±4.8 Ma to 249.6±1.3 Ma. Geochemical characteristics show that the rocks are characterized by high SiO2(74.85%~77.55%) and Na2O+K2O(5.40%~6.61%), low MgO, K2O and CaO as well as low and stable Al2O3 content. The average Rittmann index of the rhyolite is 1.15, less than 3.3. The lithochemistry feature shows that the rhyolite belongs to the calc-alkaline volcanic rocks. Main element features of the andesite show that the SiO2 content is 55.13%~56.28% and the Na2O+K2O content is 4.13%~6.15%. The average Rittmann index of the andesite is 2.20, less than 3.3. The lithochemical features show that the andesite belongs to the calc-alkaline volcanic rocks. The content of the alkaline basalt is 51.49%, Na2O+K2O is 6.34%, and the Rittmann index is 4.73, which shows that the basalt belongs to the alkaline volcanic rock. In addition, the granodiorite body of Nyixiong Formation volcanic rocks belongs to aluminous-peraluminous series of enriched LREE. These volcanic rocks are characterized by high LILE (Th, U) and LREE and obvious depletion of HFSE (Nb, Ta). The geochemical compositions of volcanic rocks belong to island arc volcanic rocks. |
| |
| Keywords: | Qamdo landmass late Permian volcanic rocks geochronology geochemistry |
| 本文献已被 CNKI 等数据库收录！ |
| 点击此处可从《岩石矿物学杂志》浏览原始摘要信息 |
| 点击此处可从《岩石矿物学杂志》下载免费的PDF全文 |
|
