| 内蒙古乌兰盖盆地中生代火山岩年代学、地球化学特征及其地质意义 |
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| 引用本文： | 孙守亮,李永飞,郜晓勇.内蒙古乌兰盖盆地中生代火山岩年代学、地球化学特征及其地质意义[J].吉林大学学报(地球科学版),2015(2):441-452. |
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| 作者姓名： | 孙守亮 李永飞 郜晓勇 |
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| 作者单位： | 沈阳地质矿产研究所/中国地质调查局沈阳地质调查中心,沈阳,110034 |
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| 基金项目： | 中国地质调查局项目(1212011121085,1212011085473,1212010782001,1212011120970) |
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| 摘 要： | 笔者对大兴安岭西部乌兰盖盆地南、北缘出露的中生代火山岩进行了详细的岩石学、激光全熔40 Ar/39 Ar测年及地球化学研究,探讨了中生代火山岩成因与地质意义。乌兰盖盆地南、北缘的中生代火山岩主要为中性岩(安山岩)与酸性岩(流纹岩)类,各类岩石总体激光全熔40 Ar/39 Ar定年结果为(151.8±1.5)~(120.2±1.8)Ma,说明其形成时代总体为晚侏罗世晚期至早白垩世;岩石总体为一套钙碱性系列到高钾钙碱性系列的中性至酸性岩石组合,各类岩石地球化学特征与壳源岩石的地球化学特征基本一致,表明它们应来自于地壳物质局部熔融形成的壳源岩浆系列。该套火山岩形成于蒙古—鄂霍茨克洋(古太平洋)闭合碰撞造山构造背景,在早白垩世151.8 Ma左右区内曾发生地壳加厚的造山过程,其岩浆深部动力学背景与岩浆源区的性质主要归因于增厚的造山带下地壳发生的部分熔融作用。
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| 关 键 词： | 乌兰盖盆地 中生代 火山岩 激光全熔40Ar/39Ar 测年 地球化学 |
Mesozoic Volcanic Rocks Geochronology and Geochemical Characteristics in Wulangai Basin of Inner Mongolia and Their Geological Significance |
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| Sun Shouliang
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Li Yongfei
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Gao Xiaoyong.Mesozoic Volcanic Rocks Geochronology and Geochemical Characteristics in Wulangai Basin of Inner Mongolia and Their Geological Significance[J].Journal of Jilin Unviersity:Earth Science Edition,2015(2):441-452. |
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| Authors: | Sun Shouliang Li Yongfei Gao Xiaoyong |
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| Institution: | Sun Shouliang;Li Yongfei;Gao Xiaoyong;Shenyang Institute of Geology and Mineral Resources/Shenyang Center of Geological Survey,China Geological Survey; |
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| Abstract: | The detailed petrology,Laser 40 Ar/3 9 Ar dating and the geochemical characteristics of the Mesozoic volcanic rocks from Wulangai basin of the Western Great Xing’an Mountain have been studied on the ground of their genesis and geological implication.We suggest that the Mesozoic volcanic rocks of Wulangai basin are mainly medium (andesite)and acid rocks (rhyolite)in the age of (15 1.8 ± 1.5 ) (120.2±1.8)Ma by the methods of Laser 40 Ar/3 9 Ar dating,identical to the Late Jurassic to Early Cretaceous.The volcanic rock types are medium to acid rocks of the Calc-Alkaline to high-K Calc-Alkaline.The geochemical characteristics is the same as crustal rocks’.This indicates that it derived from the partial melting of the crustal material.The volcanics from Wulangai basin should be result from the collision of Mongol Okhotsk (Paleo-Pacific)orogenic belt and the thickened lower crust in Early Cretaceous around 15 1.8 Ma.Combined with the background of the magma dynamics and the nature of the magma,the volcanics were from the partial melting of the thickened orogenic belt. |
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| Keywords: | Wulangai basin Mesozoic volcanic rocks Laser 40 Ar/3 9 Ar dating geochemical |
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