| 内蒙古大石寨地区二叠系碎屑锆石年龄及其构造意义 |
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| 引用本文： | 陈 贤,刘家军,周志广 柳长峰.内蒙古大石寨地区二叠系碎屑锆石年龄及其构造意义[J].中国地质,2014,41(4):1143-1158. |
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| 作者姓名： | 陈 贤 刘家军 周志广 柳长峰 |
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| 作者单位： | 中国地质大学(北京)地球科学与资源学院;中国地质大学地质过程与矿产资源国家重点实验室; |
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| 基金项目： | 中国地质调查局地质矿产调查评价专项“覆盖区矿产综合预测”(1212011085471);国家自然科学基金(40973035)联合资助 |
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| 摘 要： | 本文收集大量锆石U-Pb年代学数据,通过制作年龄-频数图谱,简略探讨了西伯利亚克拉通、华北克拉通、东北地区微地块以及内蒙古大石寨地区的演化史,并对大石寨二叠系与其周边块体的锆石年龄作比较分析,进而探讨了大石寨地区二叠系的物源问题。碎屑锆石年龄-频数图表明,大石寨地区二叠系碎屑锆石年龄可以划分出古生代年龄段(500~250 Ma),中—新元古代年龄段(1.6~0.8 Ga),新太古一古元古代年龄段(2.6~1.7 Ga)。华北克拉通北缘与西伯利亚克拉通南缘基底年龄均1.6 Ga,其二者都不能反映大石寨地区二叠系物源年龄信息,而大石寨地区二叠系碎屑锆石年龄峰值与东北地区地块年龄峰具有很好一致性,说明二者锆石年龄峰值反映的构造岩浆事件一致,表明大石寨地区二叠系物源应来源于东北地块而不是华北克拉通和西伯利亚克拉通。同时,东北地区大量古老基底锆石年龄数据的存在,暗示东北地块可能独立于上述两大板块而存在,并响应中亚造山带内存在古老微大陆的观点;东北地块由诸多微小块体拼贴而成,并分别与西伯利亚克拉通和华北克拉通碰撞拼接,缝合线分别是贺根山一黑河缝合带与西拉木伦缝合带。
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| 关 键 词： | 东北地块 大石寨 锆石U-Pb年龄对比 克拉通 |
Ages of detrital zircons from the Permian strata in Dashizhai area of Inner Mongolia and their tectonic implications |
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| CHEN Xian,LIU Jia-jun,ZHOU Zhi-guang,LIU Chang-feng.Ages of detrital zircons from the Permian strata in Dashizhai area of Inner Mongolia and their tectonic implications[J].Chinese Geology,2014,41(4):1143-1158. |
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| Authors: | CHEN Xian LIU Jia-jun ZHOU Zhi-guang LIU Chang-feng |
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| Institution: | 1. School of Earth Science and Resource, China university of Geosciences, Beijing 100083, China;2. State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China |
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| Abstract: | Abstrac: The authors collected a large number of data about U-Pb ages of zircons through compling the relative probability plot of detrital zircons, briefly discussed the evolution history of the Siberia craton, North China craton, Northeast China micro-block and Dashizhai area of Inner Mongolia. The comparative analysis of ages for the Permian strata in Dashizhai area of Inner Mongolia and the neighboring old blocks can help to study the problem of the source of Permian strata in Dashizhai area of Inner Mongolia. Based on the ages of detrital zircons from the South Siberia craton, North China craton, Northeast China micro-block and the Permian strata in Dashizai area in comparison with zircon ages of blocks in neighboring areas, the authors discussed the provenance and made research on zircons U-Pb chronology. The source of the Permian strata in Dashizhai area of Inner Mongolia was reasonably determined. The study of the ages of detrital zircons shows that detrital zircon ages of Permian strata in Dashizai area of Inner Mongolia can be divided into the Paleozoic age group (500-250 Ma), the central and late Proterozoic age group (1.6-0.8 Ga) and the late Archean age group (2.6-1.7 Ga ), whereas on the northern margin of North China craton and on the southern margin of Siberian craton, zircon U-Pb ages are earlier than 1.6Ga. Both of them fail to reflect the reasonable age information of the Permian strata source in Dashizhai area of Inner Mongolia. The age peaks of the Northeast China micro-block in China are consistent with the age peaks of the Permian strata from Dashizai area, which indicates that the provenance of the Permian strata came from the Northeast China block rather than the northern margin of North China craton and the southern margin of Siberian craton. Large quantities of ages of zircons from old basements indicate the existence of ancient micro-continents in Northeast China that may be independent of Siberia craton and North China craton, which is consistent with the view that there existed an ancient micro-continent in the central Asian orogenic belt. Northeast China block might have consisted of many small blocks after collision, and it then collided with the Siberia craton and the North China craton, with the collision taking place respectively along the Hegenshan-Heihe suture zone and Silas Mulun suture zone. |
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| Keywords: | Northeast China block Dashizai zircon U-Pb age comparison craton |
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