| 阿尔泰递增变质带中夹层石英岩的LA-ICP-MS碎屑锆石U-Pb年龄:对沉积时限及物源的限定 |
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| 引用本文： | 于根旺,王伟,赵越,刘江楠,初航,张颖慧.阿尔泰递增变质带中夹层石英岩的LA-ICP-MS碎屑锆石U-Pb年龄:对沉积时限及物源的限定[J].中国地质,2016(2):500-510. |
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| 作者姓名： | 于根旺 王伟 赵越 刘江楠 初航 张颖慧 |
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| 作者单位： | 中国地质大学地球科学与资源学院, 北京 100083;中国地质科学院地质力学研究所, 北京 100081,中国地质科学院地质力学研究所, 北京 100081,中国地质科学院地质力学研究所, 北京 100081,中国地质大学地球科学与资源学院, 北京 100083;中国地质科学院地质力学研究所, 北京 100081,天津地质矿产研究所, 天津 300170,中国地质科学院地质研究所, 北京 100037 |
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| 摘 要： | 阿尔泰造山带广泛分布各种变质沉积岩并发育典型递增变质带,变质沉积岩变质之前的沉积时代与物源特征对于限定成岩历史以及造山带演化具有重要意义。文章对采自阿勒泰组变质带中石英岩夹层样品进行了岩相学分析并采用LA-ICP-MS方法对其碎屑锆石进行了U-Pb年代学分析。共获得100个谐和或近于谐和的碎屑锆石年龄,表面年龄分布范围为(443±5)Ma至(2682±19)Ma。碎屑锆石年龄主要集中在寒武纪(486~540 Ma)并具有527~535 Ma的年龄峰值,可能源于区域内同时代的岩浆活动。新元古代年龄约占1/4,少量锆石具有古中元古代甚至太古宙年龄。结合年轻碎屑锆石年龄以及直接侵入该变质带中的英云闪长岩年龄可确定石英岩原岩的沉积时限为早志留世—早泥盆世,其后发生变质作用。古老碎屑锆石在该地区缺乏对应的岩石,可能源于区内隐伏的古老基底岩石或邻区古老陆块。
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| 关 键 词： | 阿尔泰造山带 石英岩 碎屑锆石 LA-ICP-MS U-Pb定年 |
| 收稿时间： | 2015/3/31 0:00:00 |
| 修稿时间： | 2015/5/18 0:00:00 |
LA-ICP-MS detrital zircon U-Pb ages of interbedded quartzite from the metamorphic belt of the Chinese Altay: Constraint on depositional time and provenance |
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| YU Gen-wang,WANGWei,ZHAO Yue,LIU Jiang-nan,CHU Hang and ZHANG Ying-hui.LA-ICP-MS detrital zircon U-Pb ages of interbedded quartzite from the metamorphic belt of the Chinese Altay: Constraint on depositional time and provenance[J].Chinese Geology,2016(2):500-510. |
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| Authors: | YU Gen-wang WANGWei ZHAO Yue LIU Jiang-nan CHU Hang and ZHANG Ying-hui |
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| Institution: | School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China;Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China,Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China,Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China,School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China;Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China,Tianjin Institute of Geology and Mineral Resources, Tianjin 300170, China and Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China |
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| Abstract: | Progressive metamorphic belts occur extensively in Chinese Altay. The depositional time and provenance of the metasediments in the metamorphic belts are critical for understanding the rock-forming process and the evolution of the orogen. Based on petrological analysis, the authors conducted LA-ICP-MS U-Pb analysis of detrital zircons from the quartzite narrowly interbedded in the metamorphic belt and yielded 100 concordant or nearly concordant ages with a range from (443±5) Ma to (2682± 19) Ma. Most of the detrital zircons have Cambrian ages of 486~540 Ma with the peaks between 527 and 535 Ma. One fourth of the zircon grains show Neoproterozoic ages. A few detrital zircon grains formed in the Meso-Paleoproterozoic period and even in the Archean period. Combining the youngest detrital zircon age with the emplacement time of the tonalite which directly intruded in the metamorphic belt, it could be inferred that the protolith of the quartzite deposited between the Early Silurian and the Early Devonian and later experienced metamorphism. The Cambrian and even younger detrital zircons were possibly derived from the contemporaneous igneous rocks in the region. Since the lack of Precambrian rocks in the Chinese Altay, the Precambrian detrital zircons may imply a hidden ancient basement in the region or could be ascribed to a faraway source from the neighboring block. |
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| Keywords: | Altay orogen quartzite detrital zircon LA-ICP-MS U-Pb ages |
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