Geological and Geomorphological Evidence for Activity along the Motuo Fault, Eastern Side of the Namche Barwa Syntaxis, Tibetan Plateau

2021 ◽  
Author(s):  
Chao Xie ◽  
Bengang Zhou ◽  
Fan Yang ◽  
Zhengfang Li ◽  
Yueju Cui ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Late Quaternary ◽  
Movement Pattern ◽  
Strike Slip ◽  
The Tibetan Plateau ◽  
Southeastern Part ◽  
Strong Activity ◽  
Lateral Strike Slip ◽  
Namche Barwa ◽  
Late Pleistocene To Holocene

Abstract The Motuo fault (MTF) strikes along the Yarlung Zangbo suture zone on the eastern boundary of the Namche Barwa syntaxis. The movement pattern and Quaternary activity of the MTF remain unclear, which hampers efforts to undertake meaningful seismic hazard assessments near the southeastern part of the Tibetan plateau and to understand the tectonic evolution of the Namche Barwa syntaxis. In this study, the MTF is shown to feature left-lateral strike-slip movements with offset gullies and mountain ridges and appears to have ruptured during the late Pleistocene to Holocene, as evidenced from geological, paleoseismic, and radiocarbon dating investigations. Specifically, at least three surface-rupturing paleoseismic events are revealed; two events occurred after 2606 B.P. and after 18.2 ka. Combining this information with previous Global Positioning System results in southeastern Tibet, we suggest that, as a boundary fault, the MTF regulates the movements of the Namche Barwa and Chayu blocks. The velocity difference between the two blocks advancing to the north is the main mechanism of left-lateral strike-slip motion along the MTF. The accumulation and release of shear stress between the two blocks have led to strong activity along the MTF, since the late Quaternary.

scholarly journals OSL dating of the late Quaternary slip rate on the Gyaring co Fault in central Tibet

2016 ◽  
Vol 43 (1) ◽  
pp. 162-173 ◽  
Author(s):  
Duo Wang ◽  
Gong-Ming Yin ◽  
Xu-Long Wang ◽  
Chun-Ru Liu ◽  
Fei Han ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Late Quaternary ◽  
Slip Rate ◽  
Strike Slip ◽  
Alluvial Fan ◽  
Osl Dating ◽  
The Tibetan Plateau ◽  
Slip Rates ◽  
Absolute Age ◽  
Central Tibet

Abstract The Gyaring Co Fault (GCF) is an active right-lateral strike-slip fault in central Tibet that accommodates convergence between India and Asia in the interior of the Tibetan Plateau. The average long-term slip rate of the fault remains controversial, given the absence of absolute age data of faulted geomorphic features. We have applied optically stimulated luminescence (OSL) dating to the northern segment of the GCF, revealing that the GCF has displaced alluvial fans at Aerqingsang by 500 ± 100 m since their deposition at ~109 ka, yielding a slip rate of 4.6 ± 1.0 mm/yr. A slip rate of 3.4 ± 0.4 mm/yr is inferred from analysis of an alluvial fan with an offset of 65 ± 5 m (~19 ka) at Quba site 1. The Holocene slip rate is estimated to be 1.9 ± 0.3 mm/yr, as inferred from the basal age (~8.3 ka) of terrace T1 that has a gully displacement of 16 ± 2 m at Quba site 2. These slip rates are generally lower early estimates (10–20 mm/yr), but are consistent with more recent results (2.2–4.5 mm/yr) and GPS data for other strike-slip faults in this region, indicating that deformation may be distributed across the entire Tibetan Plateau. Moreover, we suggest that the slip rate along the GCF may have decreased slightly during the late Quaternary.

Dynamics of evapotranspiration and variations in different land-cover regions over the Tibetan Plateau during 1961-2014

2021 ◽  
Author(s):  
Shan Lin ◽  
Genxu Wang ◽  
Zhaoyong Hu ◽  
Kewei Huang ◽  
Xiangyang Sun ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Land Cover ◽  
Northwestern Part ◽  
The Tibetan Plateau ◽  
Southeastern Part ◽  
Available Energy ◽  
Forest Region ◽  
Energy Factors ◽  
Term Change ◽  
Increasing Trend

AbstractIn this study, the spatiotemporal changes and driving factors of evapotranspiration (ET) over the Tibetan Plateau (TP) are assessed from 1961-2014, based on a revised generalized nonlinear complementary (nonlinear-CR) model. The average annual ET on the TP was 328 mm/year. The highest ET value (711 mm/year) was found in the forest region in the southeastern part of the TP, and the lowest value (151 mm/year) was found in the desert region in the northwestern part of the TP. In terms of the contribution of different sub-regions to the total amount of ET for the whole plateau, the meadow and steppe regions contributed the most to the total amount of ET of TP, accounting for 30% and 18.5%, respectively. The interannual ET presented a significant increasing trend with a value of 0.26 mm/year from 1961 to 2014, and a significant positive ET trend was found over 35% of the region, mainly in the southeastern part of the plateau. The increasing trend of ET in swamp areas was the largest, while that in the desert areas was the smallest. In terms of the seasonality, the ET over the plateau and different land-cover regions increased the most in summer, followed by spring, while the change in ET in winter was not obvious. The energy factors dominated the long-term change in the annual ET over the plateau. In addition, the available energy is the controlling factor for ET changes in humid areas such as forests and shrublands. Energy and water factors together dominate the ET changes in arid areas.

scholarly journals Evolution of the Yangtze River network, southeastern Tibet: Insights from thermochronology and sedimentology

Lithosphere ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 3-18
Author(s):  
Loraine Gourbet ◽  
Rong Yang ◽  
Maria Giuditta Fellin ◽  
Jean-Louis Paquette ◽  
Sean D. Willett ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Yangtze River ◽  
Middle Miocene ◽  
Strike Slip ◽  
The Tibetan Plateau ◽  
Fluvial Incision ◽  
Upper Yangtze River ◽  
Southeastern Margin ◽  
The Upper Yangtze River ◽  
Southeastern Tibet

Abstract We performed apatite and zircon (U-Th)/He dating on a granitic pluton that has been offset by ∼10 km by motion on the sinistral strike-slip Xiangcheng fault in SW Sichuan, SE Tibetan plateau, where the Shuoqu River incises a deep valley before joining the upper Yangtze River. Mean ZHe cooling ages range from 49.5 ± 2.2 Ma to 68.6 ± 6.0 Ma. Samples located above 3870 m yield mean apatite (U-Th)/He ages ranging from 30.6 ± 1.4 Ma to 40.6 ± 2.7 Ma, whereas samples at lower elevations range from 9.8 ± 1.3 Ma to 14.6 ± 2.7 Ma. In the same region, Cenozoic continental sediments are exposed on the flanks of deep valleys. They consist of unsorted conglomerates and sandstones that partly fill a paleotopography. The sediments were deposited during an episode of rapid sedimentation, followed by incision that varies between 0.5 and 1.2 km. Thermal and exhumational modeling of the granite thermochronometric data indicates rapid cooling during the middle Miocene that was likely related to fluvial incision. Our findings suggest that the upper Yangtze River and its tributary (Shuoqu) were connected by the middle Miocene. Our modeling also supports the idea that the exhumation pattern during the Cenozoic in the southeastern margin of the Tibetan Plateau is spatially and temporally heterogeneous.

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