| 华北克拉通北缘裂谷渣尔泰群LA-ICP-MS碎屑锆石U-Pb测年及地质意义 |
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| 引用本文： | 公王斌,胡健民,李振宏,董晓朋,刘洋,刘绍昌.华北克拉通北缘裂谷渣尔泰群LA-ICP-MS碎屑锆石U-Pb测年及地质意义[J].岩石学报,2016,32(7):2151-2165. |
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| 作者姓名： | 公王斌 胡健民 李振宏 董晓朋 刘洋 刘绍昌 |
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| 作者单位： | 中国地质科学院地质力学研究所, 北京 100081;国土资源部古地磁与古构造重点实验室, 北京 100081,中国地质科学院地质力学研究所, 北京 100081;国土资源部古地磁与古构造重点实验室, 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,昆明理工大学, 昆明 650093,昆明理工大学, 昆明 650093 |
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| 基金项目： | 本文受国家重点基础研究发展计划（2012CB416604）、中国地质科学院地质力学研究所基本科研业务费项目（DZLXJK201502）和国家自然科学基金项目（41472211、41502199）联合资助. |
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| 摘 要： | 华北克拉通自1.85Ga形成之后,经历了广泛的拉伸,形成了一系列中-新元古代裂谷。其中北缘裂谷由渣尔泰群、白云鄂博群及化德群组成,发育了一系列大型-超大型多金属矿床。该裂谷系形成演化的研究对认识华北克拉通中-新元古代演化及区域找矿具有重要意义。但是对于该裂谷系中渣尔泰群的时代,一直存在争议。早期认为渣尔泰群属于中元古代,主要分布于狼山地区和渣尔泰山地区。但最新的研究已将狼山地区的渣尔泰群限定为新元古代,更名为狼山群,并据此确定华北克拉通北缘存在新元古代裂谷。因此,必须对渣尔泰山地区渣尔泰群的时代进行重新限定。在此基础上可综合分析华北克拉通北缘裂谷的形成与演化。系统的LA-ICP-MS锆石U-Pb测年结果表明,渣尔泰山地区渣尔泰群碎屑锆石年龄峰值主要为1.8~1.9Ga和2.5Ga。与北缘裂谷长城系,包括白云鄂博群下部及化德群下部的碎屑锆石年龄组成特征一致。而蓟县系、待建系及青白口系存在1.1~1.35Ga、1.5~1.6Ga等较年轻的碎屑锆石年龄峰值,如白云鄂博群上部、新元古代狼山群及化德群上部。因此,渣尔泰山地区渣尔泰群整体可与长城系对比。碎屑锆石年龄组成特征表明,渣尔泰群物质主要来自华北克拉通内部的太古宙-古元古代结晶基底。综合前人对白云鄂博群、化德群及狼山群地层年龄及岩浆岩的研究成果,可确定北缘裂谷是中-新元古代多期裂解事件形成的复杂裂谷。
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| 关 键 词： | 华北克拉通 北缘裂谷 中元古代 渣尔泰群 锆石U-Pb测年 |
| 收稿时间： | 2016/1/20 0:00:00 |
| 修稿时间： | 2016/5/14 0:00:00 |
Detrital zircon U-Pb dating of Zhaertai Group in the North Margin Rift Zone of North China Craton and its implications |
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| GONG WangBin,HU JianMin,LI ZhenHong,DONG XiaoPeng,LIU Yang and LIU ShaoChang.Detrital zircon U-Pb dating of Zhaertai Group in the North Margin Rift Zone of North China Craton and its implications[J].Acta Petrologica Sinica,2016,32(7):2151-2165. |
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| Authors: | GONG WangBin HU JianMin LI ZhenHong DONG XiaoPeng LIU Yang and LIU ShaoChang |
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| Institution: | Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China;MLR Key Laboratory of Paleomagnetism and Tectonic Reconstruction, Beijing 100081, China,Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China;MLR Key Laboratory of Paleomagnetism and Tectonic Reconstruction, 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,Kunming University of Science and Technology, Kunming 650093, China and Kunming University of Science and Technology, Kunming 650093, China |
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| Abstract: | After the final amalgamation at about 1.85Ga, the North China Craton underwent broadly extension, which resulted in the formation of several Meso- to Neoproterozoic rifts. Among which, the North Margin Rift Zone is composed of Zhaertai Group, Bayan Obo group and Huade Group, and includes lots of large and super-large polymetallic deposits. Study of the formation and evolution of this rift is significant to understanding the evolution during Meso- to Neoproterozoic of North China Craton and prospecting. However, the depositional ages of Zhaertai Group are still disputed. In early stages, the Zhaertai Group distributed in Lang Shan and Zhaertai Shan was thought to be deposited during Mesoproterozoic. Recently, the Zhaertai Group developed in Langshan area has been redefined as Neoproterozoic and renamed as Langshan Group, and which suggested a Neoproterozoic rift developed in north margin of the North China Craton. Therefore, it is necessary to redefine the age of the Zhaertai Group developed in the Zhaertai Shan. According to this, we can analyze the formation and evolution of the North Margin Rift. Two main age peaks of 2.5Ga and 1.8~1.9Ga of detrital zircons have been obtained by systematically LA-ICP-MS zircon U-Pb dating of Zhaertai Group in the Zhaertai Shan, which is consistent with the Changcheng System including lower part of the Bayan Obo Group and the Huade Group in the North Margin Rift. Whereas, there are younger peak ages of detrital zircon ages of the Jixian System, Unnamed System and Qingbaikou System, such as the Langshan Group, upper part of Bayan Obo Group and Huade Group, including 1.1~1.35Ga and 1.5~1.6Ga except for the peak ages of 1.8~1.9Ga and 2.5Ga. Therefore, we can conclude that the Zhaertai Group in the Zhaertai Shan is correlated to the Changcheng System. The composition of the detrital zircon ages indicated that the detritus of Zhaertai Group are mainly sourced from Archean-Paleoproterozoic metamorphic rocks in the interior of North China Craton. The restrict of depositional age of Zhaertai Group accompanied with the ages of Bayan Obo Group, Huade Group and Langshan Group, indicated that the North Margin Rift Zone is a complicated Meso- to Neoproterozoic rift resulted from multiple extensional events. |
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| Keywords: | North China Craton North Margin Rift Mesoproterozoic Zhaertai Group Zircon U-Pb dating |
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