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为研究长江沉积物物质来源,对长江流域24个现代沉积物样品进行碎屑锆石U-Pb年龄测试,并对10个样品做Hf同位素分析,结果表明:长江河流沉积物的碎屑锆石多为岩浆成因。碎屑锆石U-Pb年龄主要有6组峰:2.4~2.6Ga,1.8~2.0Ga,700~1000Ma,400~550Ma,200~300Ma和<65Ma,其中200~300Ma和700~1000Ma为主要的两组峰。锆石U-Pb年龄谱系可区分出长江4个区段,即金沙江段、川江段、长江中游段和下游段,与地理分段相吻合。结合Hf同位素研究,可认为长江流域沉积物中生代-新生代的锆石主要来自松潘-甘孜褶皱带和秦岭造山带;古生代的锆石多来自秦岭造山带;元古代-太古代的锆石则多来自扬子克拉通、华夏地块和大别造山带。
In order to study the source of the sediments in the Yangtze River, the detrital zircon U-Pb ages of 24 modern sediment samples in the Yangtze River Basin were measured and Hf isotope analysis of 10 samples was carried out. The results show that the detrital zircons Most of the origin of the magma. The detrital zircon U-Pb age mainly has six groups of peaks: 2.4-2.6Ga, 1.8-2.0Ga, 700-1000Ma, 400-550Ma, 200-300Ma and <65Ma, of which 200-300Ma and 700-1000Ma are the major Two sets of peaks. Zircon U-Pb age pedigree can distinguish four sections of the Yangtze River, namely the Jinsha section, the Chuanjiang section, the middle reaches of the Yangtze River and the downstream section, consistent with the geographical sub-section. Based on the study of Hf isotopes, the Mesozoic-Cenozoic zircons from the sediments in the Yangtze River Basin are mainly derived from the Songpan-Ganzi fold belt and the Qinling orogenic belt. Most of the Paleozoic zircons come from the Qinling orogenic belt. Proterozoic-Archean zircons are more From the Yangtze craton, the Chinese massif and the Dabie orogenic belt.