| 大别造山带中元古代变沉积岩碎屑锆石U-Pb年代学与Hf同位素特征及其地质意义 |
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| 引用本文： | 孔令耀,郭盼,万俊,刘成新,王晶,陈超.大别造山带中元古代变沉积岩碎屑锆石U-Pb年代学与Hf同位素特征及其地质意义[J].地球科学,2022,47(4):1333-1348. |
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| 作者姓名： | 孔令耀 郭盼 万俊 刘成新 王晶 陈超 |
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| 作者单位： | 1.湖北省地质调查院，湖北武汉 430034 |
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| 基金项目： | 中国地质调查局项目(Nos.DD20190050,DD20190370)； |
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| 摘 要： | 大别造山带位于扬子陆块北缘，近年来的研究显示其发育太古代-古元古代的结晶基底，但一直缺乏中元古代的物质信息.首次报道了大别造山带核部一套中元古代“变砂岩-大理岩”变沉积岩组合，通过对该套地层的3个样品碎屑锆石U-Pb年代学和Lu-Hf同位素特征分析，显示最年轻的锆石平均年龄分别为:1 556±13 Ma、1 541±20 Ma和1 584.3±24 Ma，在误差范围内基本一致，说明该套地层的形成时代为中元古代，锆石变质增生边记录该套地层经历了124.1±2.3 Ma的变质事件，碎屑锆石年龄频谱和Lu-Hf同位素特征显示该套地层物源特征与神农架群一致；碎屑锆石峰值年龄2 682 Ma，2 461 Ma记录了“大别陆块”结晶基底两期重要生长事件，峰值年龄2 043 Ma，1 803 Ma和1 572 Ma显示“大别地块”可能参与Columbia超大陆聚合-裂解事件，在新元古代早期与“黄陵陆核”拼合而成为扬子陆块统一基底的重要组成部分.
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| 关 键 词： | 大别造山带 大别岩群 中元古代变沉积岩 碎屑锆石 U-Pb年代学 Lu-Hf同位素 地层学 |
| 收稿时间： | 2021-05-11 |
Detrital Zircon U-Pb Geochronology and Hf Isotopes of Mesoproterozoic Metasedimentary Rocks in Dabie Orogen and Its Geological Significance |
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| Kong Lingyao,Guo Pan,Wan Jun,Liu Chengxin,Wang Jing,Chen Chao.Detrital Zircon U-Pb Geochronology and Hf Isotopes of Mesoproterozoic Metasedimentary Rocks in Dabie Orogen and Its Geological Significance[J].Earth Science-Journal of China University of Geosciences,2022,47(4):1333-1348. |
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| Authors: | Kong Lingyao Guo Pan Wan Jun Liu Chengxin Wang Jing Chen Chao |
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| Abstract: | The Dabie orogen is located in the north margin of the Yangtze block. Recent studies show that the Dabie orogen has Archean-Paleoproterozoic crystalline base, but it has been lack of Mesoproterozoic material information all the time. In this article, it reports a set of Mesoproterozoic sedimentary rocks mainly composed of "metasandstone-marble" in the Dabie orogen for the first time. It analyzes the detrital zircon U-Pb chronology and Lu-Hf isotopic characteristics of the three samples in this strata, and the results show that the youngest average ages of three samples are: 1 556±13 Ma, 1 541±20 Ma and 1 584.3±24 Ma. This three ages are basically same within the error-range, which shows that the age of this strata should be the Mesoproterozoic. The metamorphic rims of detrital zircon record a metamorphic event at the age of 124.1±2.3 Ma, the U-Pb age histograms and Lu-Hf isotopes shows that the provenance characteristics of this strata are consistent with the Shennongjia Group. The main peaks of detrital zircon U-Pb ages of 2 682 Ma and 2 461 Ma record two important growth events of Dabie crystalline basement, and the peaks of 2 043 Ma, 1 803 Ma, 1 572 Ma implicate that the "Dabie block" may have participated in the aggregate event of Columbia supercontinent and become a part of it, and the "Dabie block" separated from the Columbia supercontinent during the breaking up event, and collided with the "Huangling continental nucleus" and became an important part of the basement of the Yangtze block during the Early Neoproterozoic. |
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