华北北缘泥盆纪查干哈布组物源特征及其构造意义  

Provenance Characteristic of Devonian Chaganhabu Formation in the Northern Margin of the North China Craton and Its Tectonic Significance

作　　者：李普庆 宋东方[1,2,3] 曾浩 Li Puqing;Song Dongfang;Zeng Hao(State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Innovation Academy for Earth Science,CAS,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院地质与地球物理研究所,岩石圈演化国家重点实验室,北京100029 [2]中国科学院地球科学研究院,北京100029 [3]中国科学院大学地球与行星科学学院,北京100049

出　　处：《地球科学》2023年第3期1205-1216,共12页Earth Science

基　　金：国家自然科学基金项目(Nos.41730210,41672219)。

摘　　要：白乃庙岛弧带位于华北克拉通北缘,其与华北克拉通北缘的拼贴时限,是理解华北克拉通北缘增生过程的关键.为了限定弧-陆碰撞的时限,对白乃庙岛弧与华北克拉通拼合带的早古生代沉积地层——查干哈布组开展了锆石U-Pb定年和锆石Lu-Hf同位素测试.结果显示,查干哈布组中3颗最年轻锆石的加权平均年龄为393.5±4.9Ma.综合锆石年龄和前人化石资料,限定查干哈布组最大沉积年龄为早泥盆世晚期.碎屑锆石U-Pb年龄谱和Hf同位素组成显示查干哈布组的物源为白乃庙岛弧带,基本没有来自华北克拉通的物源.研究结果结合区域资料表明,白乃庙岛弧带与华北克拉通北缘在早泥盆世可能仍未发生弧-陆碰撞.The Bainaimiao arc belt is located in the northern margin of the North China Craton.The exact time of the collision between the Bainaimiao arc belt and the North China Craton is thus a key for understanding the accretionary process of the northern margin of the North China Craton.In order to constrain the collision time of the Bainaimiao arc belt and the North China Craton,this study carried out zircon U-Pb age dating and zircon Lu-Hf isotope analysis of the Chaganhabu Formation.The weighted average age of the three youngest zircons from the Chaganhabu Formation is 393.5±4.9 Ma,consistent with previous paleontological reports.Therefore,the maximum deposition age of the Chaganhabu Formation is the late Early Devonian.Moreover,the characteristic of zircon U-Pb age spectra and Hf isotope of the Chaganhabu Formation is similar to that of the Bainaimiao arc belt and different from that of the North China Craton,which means that the provenance of the Chaganhabu Formation is the Bainaimiao arc belt rather than the North China Craton.Combined with regional tectonic research,these data indicate that during the Early Devonian,there was still a wide ocean between the Bainaimiao arc belt and the northern margin of the North China Craton,and the arc-continent collision has not yet occurred.

关 键 词：白乃庙岛弧带 查干哈布组 锆石U-Pb年龄 锆石HF同位素 物源特征 构造地质 

分 类 号：P542[天文地球—构造地质学] P597[天文地球—地质学]