The Mechanism of Tectonic Deformation of the Central Yunnan Terrane in the Late Cenozoic Based on Tectonic Geomorphology

被引：0
作者：
Wang D. [1 ]
Dong Y. [1 ]
Jiao Q. [1 ]
Zhang D. [1 ]
Duan J. [2 ]
Yu H. [1 ]
机构：
[1] Faculty of Land and Resource Engineering, Kunming University of Science and Technology, Kunming
[2] China Southwest Geotechnical Investigation & Design Institute Co., Ltd., Chengdu
来源：
Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences | 2022年 / 47卷 / 08期
关键词：
Central Yunnan Terrane; fluvial geomorphology; relative tectonic activity; tectonic deformation mechanism; tectonics; the Cenozoic;
D O I：
10.3799/dqkx.2021.146
中图分类号：
学科分类号：
摘要：
The Central Yunnan Terrane, with internal faults developed, is located in the Southeast of the Tibetan Plateau, which is an ideal place to study the Cenozoic tectonic deformation mechanism of this area. The Cenozoic deformation mechanism of the Central Yunnan Terrane is controversial, and there are two main types of deformation mechanism: "lower crustal flow" and the "rigid block extrusion". The former proposed that the tectonic activity of the block is more uniform, and the latter proposed that the tectonic activity is more intense along the fault. The tectonic activity of different mechanisms has different responses on the surface, and the geomorphic index is extremely sensitive to the tectonic activity response. To determine the tectonic deformation mechanism of the Cenozoic in this study area, 319 basins (sub-basins) were extracted based on the SRTM-3 Digital Elevation Model (DEM) with a resolution of 30 m. Indices used include hypsometric curve and hypsometric integral (HI), drainage basin shape (BS), asymmetric factor (AF), normalized stream-length gradient (SLK), and the ratio of valley floor width to valley height (VF). Results from the analysis are accumulated and expressed as an index of relative active tectonics (Iat), which we divide into four classes from relatively low to highest tectonic activity. The results are: The Iat values of the Lijiang-Xiaojinhe fault zone, Zemuhe-Xiaojiang fault zone, and Red River fault zone in the Central Yunnan are relatively small, and they gradually increase from north to south, which is consistent with the "rigid block extrusion" mode. At the same time, the Iat value on both sides of the Jinsha River is relatively low it shows that the geomorphic activity is strong, which may be due to the uplift of the Central Yunnan block and river system reconstitution, and the resulting knick points are transmitted upstream. During the migration of the cracks, they are transmitted from the main river channel to the secondary river channel, which affects the increase of the HI, BS and SLK value and the decrease of the VF value, making the relative tectonic activity stronger. © 2022 China University of Geosciences. All rights reserved.
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页码：3016 / 3028
页数：12
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