| 鄂西清江中上游高海拔砾石层ESR定年及地质意义 |
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| 关键词:high elevation gravels ESR dating upper and middle reaches of the Qingjiang River the formation of the Qingjiang River cut-through of the Yangtze Three Gorges |
| 基金项目:中国地质调查局国土资源大调查项目(编号: 1212010911016; 1212010814057) |
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| ESR Dating of the High Elevation Gravels in the Upper and Middle Reaches of the Qingjiang River and Its Significance |
| Quite a few high elevation gravels were found in the upper and middle reaches of the Qingjiang River within Jianshi, Badong and Lichuan areas, west Hubei Province. Characteristics of these gravels suggest that they are probably the “high terrace” of the NNE-trending ancient drainage system. ESR dating of the high elevation gravels indicates that the gravels were formed between the early and middle Pleistocene (677±67)-(789±78) ka in the middle reaches of the Qingjiang River, and in the middle period of middle Pleistocene (371±37)-(551±55) ka in the upper reaches, implying that there existed a NNE-trending ancient drainage system which was developed in the middle reaches of the Qingjiang River in early and middle Pleistocene, and this development lasted until the middle period of middle Pleistocene in the upper reaches of the Qingjiang River. This probably implies that the capture of the middle reaches by the Qingjiang River probably occurred between the early and middle Pleistocene, and the capture of the upper reaches took place in the middle period of middle Pleistocene. The modern Qingjiang River has been formed since the middle period of middle Pleistocene. The same geological background (last rapid uplift of the Tibetan Plateau) indicates that the phenomenon that the Yangtze River cut through the Three Gorges is probably attributed to the constantly attack from east to west, which, however, took place a bit earlier than things of the Qingjiang River. |
| WANG Ling-zhan,TU Bing,TIAN Yang,XIE Guo-gang,ZENG Bo-fu.2012.ESR Dating of the High Elevation Gravels in the Upper and Middle Reaches of the Qingjiang River and Its Significance[J].Acta Geoscientica Sinica,33(3):316-322. |
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