The subducted slab of Yangtze continental block beneath the Tethyan orogen in western Yunnan
- 60 Downloads
The western Yunnan area is a natural laboratory with fully developed and best preserved Tethyan orogen in the world. Seismic tomography reveals a slab-like high velocity anomaly down to 250 km beneath the western Yunnan Tethyan orogen, to its west there is a low-velocity column about 300 km wide. In the region from Lancangjiang to Mojiang an obvious low velocity in the lower crust and uppermost mantle overlies on the slab. Synthesizing the available geological and geochemical results, the present paper demonstrates that this slab-like high velocity anomaly is a part of the subducted plate of Yangtze continental segment after the closure of Paleotethys. The collision of India and Eurasia continent starting from 50–60 MaBP might trigger thermal disturbance in the upper mantle and cause the uprising of asthenosphere, in that case the subducted Yangtze plate could be broken off, causing Cenozoic magmatic activities and underplating in the Lancangjiang-Mojiang region.
Keywordsseismic tomography Tethyan orogen in western Yunnan subduction remains of Yangtze Block
Unable to display preview. Download preview PDF.
- 1.Liu Guangding, Discussion on earth sciences, Earth Science Frontiers, 1998, 5: 1.Google Scholar
- 4.Liu Futian, Liu Jianhua, Wu Hua et al., Seismic Tomography of the Japan and Adjacent Regions, Geophysics in China in the Eighties, Beijing: Xueqiu Magazine Publishing House, 1989, 260–274.Google Scholar
- 11.Zhong Dalai, Paleotethysides in West Sichuan and Yunnan, China (in Chinese), Beijing: Science Press, 1998.Google Scholar
- 12.Ren Jishun, Jin Xiaochi, New observations of the Red River fault, Geologocal Review (in Chinese), 1996, 42: 439.Google Scholar
- 14.Bijwaard, H., Spakman, W., Engdahl, R., Closing the gap between regional and global travel time tomography, J. Geophys. Res., 1999.Google Scholar
- 15.Zhou, H. A., A high resolution P-wave model for the top 1 200 km of the the mantle, Geophys. Res., 1996, 101: 22791.Google Scholar
- 18.Liu Jianhua, Liu Futian, Wu Hua et al., Three-dimensional velocity images of the crust and upper mantle beneath north-south zone in China, Acta Geophysica Sinica (in Chinese), 1989, 32: 143.Google Scholar
- 19.Xu Peifen, Sun Ruomei, Liu Futian et al., Evidence of Seismic Tomography for subduction and break-off of the Yangtze plate, Chinese Science Bulletin (in Chinese), 1999, 44(15): 1658.Google Scholar
- 20.Jian Ping, Wang Xianfeng, He Longqing, Preliminary study on U-Pb chronology of the Shuangqou ophiolite, Xinping County, Yunnan, Acta Petrologica Sinica (in Chinese), 1998, 14: 207Google Scholar
- 23.Huang Zhilong, Wang Liankui, The geochemistry of the lamprophyre in the Laowangzhai gold mine, Yunnan, Geochimica (in Chinese), 1966, 25: 255.Google Scholar
- 24.Bi Xianwu, Hu Ruizhong, Yang Mingyou, Metallogenic epoch of the Ailaoshan gold ore zone and discussion on its matallogenic mechanism, Geology and Geochemistry (in Chinese), 1996, 1: 94.Google Scholar