江汉盆地河流碎屑锆石U-Pb年龄特征及其对物源研究的启示  

Detrital Zircon U-Pb Age Characteristics of Main Rivers around Jianghan Basin and Implications of Provenance Tracing

作　　者：林旭 吴中海[2] 赵希涛[3] 张洋[1] 陈济鑫 刘海金 LIN Xu;WU Zhong-hai;ZHAO Xi-tao;ZHANG Yang;CHEN Ji-xin;LIU Hai-jin(College of Civil Engineering and Architecture,Three Gorges University,Yichang,Hubei 443002;Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081;Institute of Geology and Geophysics,Chinese Academy of Science,Beijing 100029;School of Earth Sciences,East China University of Technology,Nanchang,Jiangxi 330013)

机构地区：[1]三峡大学土木与建筑学院,湖北宜昌443002 [2]中国地质科学院地质力学研究所,北京100081 [3]中国科学院地质与地球物理研究所,北京100029 [4]东华理工大学地球科学学院,江西南昌330013

出　　处：《地球学报》2022年第1期73-81,共9页Acta Geoscientica Sinica

基　　金：国家自然科学基金项目(编号:41972212)资助。

摘　　要：江汉盆地位于扬子板块北部,是长江演化研究的关键地区。锆石是河流沉积物中常见的副矿物,其U-Pb年龄谱对比被广泛用于物源示踪研究,但在江汉盆地还未系统研究。本文利用激光剥蚀电感耦合等离子质谱(LA-ICP-MS)分别对江汉盆地12条流入河流进行了922颗碎屑锆石U-Pb年龄分析,结合多维判别图(MDS)和已报道的河流碎屑锆石U-Pb年龄结果,探讨江汉盆地主要流入河流的碎屑锆石U-Pb年龄异同性,结果表明长江、沮漳河和清江的碎屑锆石U-Pb峰值年龄组成存在差异;作为江汉盆地输沙量最大的两条河流,长江和汉江的碎屑锆石U-Pb年龄组成存在明显不同;大别山的河流同时与汉江和长江的碎屑锆石U-Pb年龄组成存在差异;发源于幕府山的陆水和汨罗江的碎屑锆石U-Pb年龄组成与长江和湘江的不同;武陵山的清江、澧水和沅江的碎屑锆石U-Pb年龄组成与湘江、资江的存在差异。这些差异体现了区域性物源区对这些河流碎屑物质组成的影响。因而,利用江汉盆地周缘河流碎屑锆石U-Pb年龄存在的差异,将其用于江汉盆地盆山耦合和大河演化研究具有良好的应用前景。Jianghan Basin,located in the north of the Yangtze Plate,is a key area for the study of the evolution of the Yangtze River.Zircon is a common accessory mineral in fluvial sediments,and its U-Pb age spectrum has been widely used in provenance tracing studies.However,it has not been systematically studied in Jianghan Basin.In this study,the U-Pb ages of 922 detrital zircons from 12 inflow rivers in the Jianghan Basin were analyzed using laser denudation inductively coupled plasma mass spectrometry(LA-ICP-MS).A multidimensional discriminant map(MDS)combined with the reported U-Pb ages of detrital zircons from rivers was employed to assess the U-Pb ages of detrital zircons from 12 inflow rivers.Further,the U-Pb age variation of detrital zircons from the main inflow rivers in Jianghan Basin was discussed herein.The U-Pb peak age composition of detrital zircons from the Yangtze River,Juzhang River,and Qingjiang River is different.The U-Pb age of detrital zircons in the Yangtze River and Hanjiang River,the two rivers with the largest sediment transport capacity in the Jianghan Basin,are different.The U-Pb age composition of detrital zircons in the Dabie Mountains is different from that of Hanjiang River and the Yangtze River.The U-Pb age composition of detrital zircons from the Mufu Mountains are different from the Yangtze River and the Xiangjiang River.The U-Pb age composition of detrital zircons from Qingjiang,Lishui and Yuanjiang rivers in the Wuling Mountains are different from Xiangjiang and Zijiang rivers.These differences reflect the influence of regional provenance on the sedimentary material composition of these streams.Therefore,the U-Pb ages of detrital zircons from the surrounding rivers of the Jianghan Basin have a good application prospect in the study of basin-mountain coupling and river evolution in the Jianghan Basin.

关 键 词：江汉盆地 锆石 U-PB年龄 物源示踪 

分 类 号：P597[天文地球—地球化学]