| 大兴安岭满归地区变中酸性火山岩LA-ICP-MS锆石U-Pb年龄及其地质意义 |
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| 作者姓名： | 李中会 李睿杰 李阳 沙环宇 |
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| 作者单位： | 1. 黑龙江省地质调查研究总院,哈尔滨 150036; 2. 黑龙江省齐齐哈尔地质勘查总院,齐齐哈尔 161006 |
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| 基金项目： | 中国地质调查局“黑龙江1∶25万漠河幅、漠河县幅区调修测(编号: 1212011120653,1212010881209)”项目资助 |
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| 摘 要： | 对大兴安岭满归地区新元古界—下寒武统大网子组变中酸性火山岩进行锆石U-Pb同位素年代学研究,探讨其形成时代及地质意义。大网子组由变安山岩、变英安岩、变流纹岩和少量变晶屑凝灰岩组成,缺少板岩、变砂岩、片岩等沉积岩夹层。通过对变安山岩进行锆石U-Pb同位素年龄测定,获得其锆石206Pb/238U加权平均年龄为(199±1) Ma,表明大网子组变中酸性火山岩形成于早侏罗世早期,非前人认为的形成于新元古代—早寒武世。额尔古纳地块早侏罗世火山岩为漠河盆地提供了物源,表明额尔古纳地块在早侏罗世处于火山-岩浆弧构造背景。该研究为蒙古—鄂霍茨克洋闭合过程中的地球动力学研究提供了新资料。
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| 关 键 词： | 变中酸性火山岩 LA-ICP-MS锆石U-Pb年龄 早侏罗世 大兴安岭北部 |
| 收稿时间： | 2018-12-24 |
LA-ICP-MS zircon U-Pb ages and geological significance of the meta-intermediate-acidic volcanic rocks in Mangui area of Da Hinggan Mountains |
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| Authors: | LI Zhonghui LI Ruijie LI Yang SHA Huanyu |
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| Institution: | 1. Heilongjiang Institute of Geological Survey, Harbin 150036, China; 2. Heilongjiang Qiqihar Institute of Geological Exploration, Qiqihar 161006, China |
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| Abstract: | Through the zircon U-Pb isotopes chronology research of the meta-intermediate-acidic volcanic rocks of Neoproterozoic-Lower Cambrian Dawangzi Formation in Mangui area of Da Hinggan Mountains, the authors explored the forming age and geological significance of the rocks. Dawangzi Formation is composed of meta-andesite, meta-dacite, rhyolite and a small amount of meta-crystalline tuff, and lacks interbeds of sedimentary rocks such as slate, metasandstone and schist. The authors determined the zircon U-Pb isotopes age of the meta-andesite, and the zircon 206Pb/238U weighted mean age is (199±1) Ma, indicating that the forming age of Dawangzi Formation meta-intermediate-acidic volcanic rocks is the early stage of Early Jurassic, not Neoproterozoic-Early Cambrian as in previous research. Early Jurassic volcanic rocks distributed in Erguna Block provide a provenance for Mohe Basin. Erguna Block was in the volcano-magmatic arc tectonic background in Early Jurassic. This research supplies new data for the geodynamics study during the closure of Mongolia-Okhotsk Ocean. |
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| Keywords: | meta-intermediate-acidic volcanic rocks LA-ICP-MS zircon U-Pb age Early Jurassic Northern Da Hinggan Mountains |
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