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摘要
The Xar Moron River, which is the boundary between the North China plate and Xing-Meng Orogenic Belt, flows above the fault of the Xar Moron. In this paper, we applied the ICP-MS analytical techniques to date U-Pb ages and determine Hf isotopic composition of detrital zircons in the floodplain sediments from the Xar Moron River. The detrital zircons U-Pb ages of sample XL show 4 populations: 108 similar to 550Ma, 699 similar to 918Ma, 1789 similar to 2109Ma, 2347 similar to 2633Ma, and the detrital zircons U-Pb ages of sample XL2 show 3 populations: 122 similar to 526Ma, 1791 similar to 1969Ma, 2176 similar to 2692Ma, respectively. There does not exist zircons with 700 similar to 900Ma age in the sample XL2, and the detrital zircons with ages of 1791 similar to 1969Ma and 2176 similar to 2692Ma also belong to the North China plate. Therefore, the sample XL2 should have detrital zircons which originated from the North China plate. According to Lu-Hf isotopic composition, a large proportion of detrital zircons show the characteristic of Xing-Meng Orogenic Belt, whose Hf model ages (t(DM2)) are less than 1000Ma and epsilon(Hf)(t) are greater than 0. t(DM2) of some detrital zircons are close to 2. 7Ga, which is the fastest growth period of the North China plate. From the above, floodplain sediments of the Xar Moron River have the common features between the North China plate and Xing-Meng Orogenic Belt. But the absence of detrital zircon with age of 700 similar to 900Ma in sample XL2 resulted from sorting of river through grain size analysis and Xiliao River U-Pb ages. Through linear mixing model of U-Pb ages and t(DM2), of detrital zircons, fitted cumulative probability curve suggests that mixing ratio between the North China plate and Xing-Meng Orogenic Belt is 1 : 1. Furthermore, using formula of recycling ratio, ratios between remelting and juvenile crust with age have been calculated.
- 出版日期2013-9
- 单位中国地质大学（北京）
