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| Monazite age spectra in the Late Cenozoic strata of the Changjiang delta and its implication on the Changjiang run-through time | |
| 作者姓名： | Yokoyama Kazumi |
| 作者单位： | Department of |
| 摘 要： | Uplift of the Tibetan Plateau, inversion of eastern and western geomorphology, eastward flowing of large rivers, and run-through of the Changjiang River exert great influence on sedimentation and environ-mental variations in the East China Sea. Provenance discrimination of Tibetan-Plateau-originated sediments in the river-mouth areas and marginal seas is key to figure out these issues.In the past, most studies of the run-through time of the Changjiang and the Yellow rivers focused on geomo… |
Monazite age spectra in the Late Cenozoic strata of the Changjiang delta and its implication on the Changjiang run-through time |
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| Yokoyama Kazumi.Monazite age spectra in the Late Cenozoic strata of the Changjiang delta and its implication on the Changjiang run-through time[J].Science in China(Earth Sciences),2005,48(10). | |
| Authors: | FAN Daidu LI Congxian Yokoyama Kazumi ZHOU Baochun LI Baohua WANG Qiang YANG Shouye DENG Bing WU Guoxuan |
| Institution: | 1. State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China 2. Department of Geology, National Science Museum, Tokyo, Japan 3. Shanghai Natural Museum, Shanghai 200002, China 4. Tianjin Institute of Geological and Mineral Resources, Tianjin 300170, China |
| Abstract: | The Late Cenozoic strata are 313 m thick, revealed by the drilling core PD-99 in the south Changjiang delta. Monazite chemical dating shows that 350-500-Ma monazites predominate in the Pliocene and 100-275-Ma monazites in the Quaternary, indicating a great change of their provenance. The first presence horizon of monazites younger than 25 Ma is just above the Matruyama/Gauss boundary (~2.58 Ma), whch is exactly when uplift of the Tibetan Plateau began to influence deposition in the East China Sea. Variations in contents of monazites younger than 25 Ma can be divided into two sections. The Early-Middle Pleistocene with less <25 Ma monazites corresponds with rapid uplift of the Tibetan Plateau, and the Late Pleistocene with more <25 Ma monazites parallels the peak uplift of the Tibetan Plateau. This study demonstrates that chemical dating of monazites in the river-mouth strata is a useful method to explore changes of river drainage basins, and deconvolute multistage tectonic and magmatic activity histories in the provenance areas. |
| Keywords: | delta monazite electron microprobe chemical dating formation of the Changjiang uplift of the Tibetan Plateau |
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