| 华北南缘中元古界高山河群碎屑锆石U-Pb年代学及其地质意义* |
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| 引用本文： | 王淼,周洪瑞,张恒.华北南缘中元古界高山河群碎屑锆石U-Pb年代学及其地质意义*[J].古地理学报,2020,22(1):39-55. |
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| 作者姓名： | 王淼 周洪瑞 张恒 |
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| 作者单位： | 1.中国地质大学(北京)地球科学与资源学院,北京 100083;2.中国地质科学院地质研究所,北京 100037 |
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| 基金项目： | *中国地质调查局项目(编号:DD20190370)和科技部基金项目(批准号:2015FY310100)联合资助 |
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| 摘 要： | 为了探讨华北板块南缘中元古代沉积地层的时代归属和物质来源、区域古地理格局和大地构造特征,对豫西灵宝福地地区的高山河群进行碎屑锆石U-Pb年代学和锆石微量元素特征研究。获得的高山河群年龄最小(年轻)的单颗碎屑锆石 207Pb/206Pb 年龄值为1685±39 Ma,从而限制了高山河群最早沉积年龄不早于1700 Ma。结合上覆的龙家园组年代学标定(1594±12 Ma),将高山河群的形成年代限定为1700—1600 Ma,即中元古代长城纪的中晚期,属国际地质年表的“固结纪”。高山河群中碎屑锆石 207Pb/206Pb 年龄范围为1685—2751 Ma,呈现1850 Ma、2150 Ma、2300 Ma和2500 Ma共4个年龄峰值,对应于华北克拉通古元古代重要的地质事件,并且高山河群以1850 Ma和2500 Ma峰值年龄段的地质体为主要的物源区。根据高山河群与云梦山组碎屑锆石年龄频率对比,推测在豫西地区西侧存在以往报道较少的年龄为2500 Ma的地质体。根据熊耳群火山岩及其对应锆石的地球化学特征和熊耳期盆地动力学性质,并结合高山河群沉积相特征和沉积盆地构造属性,认为熊耳群形成于与“岛弧”共生的拉张性质的弧后盆地地区,而其上覆的高山河群为弧后盆地靠近大陆一侧的具有被动大陆边缘性质的滨浅海沉积。
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| 关 键 词： | 华北克拉通 高山河群 碎屑锆石U-Pb年代学 物源分析 大地构造 |
| 收稿时间： | 02 May 2019 |
Detrital zircon geochronology and tectonic implications of the Mesoproterozoic Gaoshanhe Group in south margin of North China Craton |
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| Wang Miao,Zhou Hong-Rui,Zhang Heng.Detrital zircon geochronology and tectonic implications of the Mesoproterozoic Gaoshanhe Group in south margin of North China Craton[J].Journal of Palaeogeography,2020,22(1):39-55. |
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| Authors: | Wang Miao Zhou Hong-Rui Zhang Heng |
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| Institution: | 1.School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China;2.Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China |
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| Abstract: | In order to investigate the age attribution of the Mesoproterozoic sedimentary strata,regional paleogeographic pattern and tectonic evolution in the southern margin of the North China Craton(NCC),this study reports U-Pb geochronology and characteristics of trace elements of detrital zircons from the Gaoshanhe Group in the Lingbao-Fudi area of the western Henan Province. The 207Pb/206Pb age of the youngest zircon of the Gaoshanhe Group is 1685±39 Ma,which limited the earliest sedimentary age of the Gaoshanhe Group is no earlier than 1700 Ma. Combined with the chronological calibration of the Longjiayuan Formation(1594±12 Ma)overlying the Gaoshanhe Group,the age of the Gaoshanhe Group was limited to 1700-1600 Ma,which is the middle and late period of the Mesoproterozoic Changcheng period,corresponding to the international Statherian Period. The 207Pb/206Pb ages of the detrital zircons from the Gaoshanhe Group range from 1685 Ma to 2751 Ma,presenting four age peaks of 1850 Ma,2150 Ma,2300 Ma and 2500 Ma,corresponding to the Paleoproterozoic geological events of the North China Craton. The provenance of the Gaoshanhe Group is dominated by geological body of the 1850 Ma peak age and the 2500 Ma peak age. According to thecomparison of age frequency of detrital zircons in the Gaoshanhe Group and Yunmengshan Formations,it is speculated that there are 2500 Ma geological bodies reported less frequently in the west of the western Henan area. According to the geochemical characteristics of the Xionger Group volcanic rocks and their corresponding zircons,the basin dynamic property during the deposition of the Xionger Group,and the sedimentary properties of the Gaoshanhe Group and tectonic property of the sedimentary basin,the Xionger Group was most likely formed in the post-arc basin symbiotic with “island arcs” and the Gaoshanhe Group overlying the Xionger Group was deposited near the shore and shallow sea of passive continental marginal and close to the continental side of the back-arc basin. |
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| Keywords: | North China Craton Ganshanhe Group detrital zircon U-Pb geochronology provenance analysis tectonic |
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