| 延边地区明南洞岩体的成因及构造背景：岩石地球化学、锆石U-Pb年龄的制约 |
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| 引用本文： | 雷聪聪 李世超 刘正宏 徐仲元 张,超 白新会.延边地区明南洞岩体的成因及构造背景：岩石地球化学、锆石U-Pb年龄的制约[J].中国地质,2014,41(4):1328-1340. |
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| 作者姓名： | 雷聪聪 李世超 刘正宏 徐仲元 张 超 白新会 |
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| 作者单位： | 吉林大学地球科学学院; |
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| 基金项目： | 国家自然科学基金项目(41272223、41340024)联合资助 |
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| 摘 要： | 通过野外观测、锆石LA-ICP-MS U-Pb同位素测定及岩石地球化学等手段,详细地对延边地区明南洞岩体进行了研究。研究表明,延边地区明南洞岩体的成岩年龄为(180.5±0.7)Ma,为早侏罗世岩浆事件的产物。明南洞岩体中SiO_2含量为60.71%~67.72%,Al_2O_3含量为15.60%~17.44%,全碱(Na_2O+K_2O)值为6.79%~7.63%,K_2O/Na_2O值为0.61~1.01,A/CNK=0.94~1.01,属高钾钙碱性I型花岗岩,并具有富集轻稀土元素和大离子亲石元素,亏损重稀土元素和高场强元素的特征。以上特征表明,明南洞岩体具有显著的活动大陆边缘及火山弧花岗岩的特点。延边—太平岭地区的陆缘钙碱性、高钾钙碱性花岗岩到张广才岭—小兴安岭地区的双峰式火山岩组合,构成了平行洋壳俯冲方向的成分分带,指示了俯冲的方向,反映了早侏罗世古太平洋板块的俯冲作用。
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| 关 键 词： | 岩石地球化学 早侏罗世 LA-ICP-MS 锆石U-Pb 延边地区 |
Petrogenesis and tectonic setting of Mingnandong pluton in Yanbian area: Constraints from petro-geochemistry and zircon U-Pb ages |
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| LEI Cong-cong,LI Shi-chao,LIU Zheng-hong,XU Zhong-yuan,ZHANG Chao,BAI Xin-hui.Petrogenesis and tectonic setting of Mingnandong pluton in Yanbian area: Constraints from petro-geochemistry and zircon U-Pb ages[J].Chinese Geology,2014,41(4):1328-1340. |
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| Authors: | LEI Cong-cong LI Shi-chao LIU Zheng-hong XU Zhong-yuan ZHANG Chao BAI Xin-hui |
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| Institution: | College of Earth Sciences, Jilin University, Changchun 130061, Jilin, China |
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| Abstract: | Abstract: In this paper Mingnandong pluton was studied throughly by such means as field observation, LA-ICP-MS zircon U-Pb isotopic measurement and petro-geochemistry. The results show that Mingnandong pluton was formed in the Early Jurassic (180.47±0.71Ma). Chemical analyses yielded the following data for Mingnandong pluton: SiO2=60.71%-67.72%, Al2O3=15.60%-17.44%, Na2O+K2O=6.79%-7.63%, K2O/Na2O=0.61-1.01 and A/CNK=0.94-1.01, implying high-potassium calc-alkaline I-type granites. Besides, Mingnandong pluton is enriched in light rare earth elements and large ion lithophile elements, and depleted in heavy rare earth elements and high field strength elements. These features suggest that Mingnandong pluton has obvious characteristics of active continental margin and volcanic arc granites. The ingredient zonation parallel to the orientation of the subduction of oceanic crust made up of cale-alkaine, high-K calc-alkaline granites and the bimodal volcanic rock association from Yanbian and Taiping Mountain to Xiao Hinggan Mountains and Zhangguangcai Mountain indicate the orientation of the subduction of ancient Pacific plate. In a word, the emplacement of Mingnandong pluton was influenced by the subduction of ancient Pacific plate in the Early Jurassic. |
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| Keywords: | geochemistry early Jurassic LA-ICP-MS zircon U-Pb dating Yanbian area |
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