Affiliation:
1. Guangdong Provincial Key Laboratory of Geodynamics and Geohazards School of Earth Sciences and Engineering Sun Yat-Sen University Guangzhou 510275 China sysu.edu.cn
2. Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) Zhuhai 519082 China sysu.edu.cn
3. State Key Laboratory of Earthquake Dynamics Institute of Geology China Earthquake Administration Beijing 100029 China cea.gov.cn
4. Gansu Lanzhou Geophysics National Observation and Research Station Lanzhou 730000 China
Abstract
Abstract
The Elashan fault (ELSF) and Qinghainanshan fault (QHNF), two major faults developed around the Qinghai Lake and Chaka-Gonghe basins, are of great importance for investigating the deformation model of the internal northeastern Tibetan Plateau. However, their late Pleistocene slip rates remain poorly constrained. In this study, we combine high-resolution topography acquired from unmanned aerial vehicles (UAV) and geomorphological dating to calculate the slip rates of the two faults. We visited the central ELSF and western QHNF and measured displaced terraces and stream channels. We collected 10Be samples on the surface of terraces to constrain the abandonment ages. The dextral slip rate of the central segment of the Elashan fault is estimated to be 2.6±1.2 mm/yr. The uplift rates since the late Pleistocene of the Elashan and Qinghainanshan faults are 0.4±0.04 mm/yr and 0.2±0.03 mm/yr, respectively. Comparing the geological rates with the newly published global positioning system (GPS) rates, we find that the slip rates of the major strike-slip faults around the Qinghai Lake and Chaka-Gonghe basins are approximately consistent from the late Pleistocene to the present day. The overall NE shortening rates by summing up the geological slip rates on major faults between the East Kunlun and Haiyuan faults are ~3.4 mm/yr, smaller than the geodetic shortening rates (~4.9 to 6.4 mm/yr), indicating that distributed deformation plays an important role in accommodating the regional deformation. By analyzing the geometrical and kinematic characteristics of the major faults surrounding the basins, we suggest that the kinematic deformation of the internal northeastern Tibet is a nonrigid bookshelf model that consists of counterclockwise rotation (~0.8° Myr-1) and distributed thrusting.
Funder
Guangdong Province Introduced Innovative R&D Team of Geological Processes and Natural Disasters around the South China Sea
National Natural Science Foundation of China
Tibet Scientific Expedition and Research Program
Cited by
3 articles.
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