Rift propagation in south Tibet controlled by under-thrusting of India: A case study at the Tangra Yumco graben (south Tibet)
- 1Institut für Geologie und Paläontologie, Westfälische Wilhelms-Universität Münster, Münster, Germany (rahetzel@uni-muenster.de)
- 2Institut für Sedimentologie und Umweltgeologie, Universität Göttingen, Goldschmidtstr. 3, 37077 Göttingen, Germany
- 3CNPC Key Laboratory of Carbonate Reservoirs, Southwest Petroleum University, Chengdu 610500, China
- 4Institute of Geological Sciences, Polish Academy of Sciences, Senacka 1, 31-002 Kraków, Poland
- 5State Key Laboratory of Tibetan Plateau Earth System Science, Resources and Environment, (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
Active graben systems in south Tibet and the Himalaya are the expression of ongoing E-W extension, however, the cause and spatio-temporal evolution of normal faulting remain debated. We reconstruct the history of normal faulting at the southern Tangra Yumco graben by using new thermochronological data and thermo-kinematic modelling (Wolff et al., 2022). The Miocene cooling history of the footwall of the main graben-bounding fault is constrained by zircon (U-Th)/He ages between 16.7±1.0 and 13.3±0.6 Ma, apatite fission track ages (15.9±2.1 to 13.0±2.1 Ma), and apatite (U-Th)/He ages (7.9±0.4 to 5.3±0.3 Ma). Thermo-kinematic modelling of the data indicates that normal faulting began 19.0±1.1 Ma ago at a rate of ~0.2 km/Myr and accelerated to ~0.4 km/Myr at ~5 Ma. In the northern Tangra Yumco rift, re-modelling of published thermochronological data (Wolff et al., 2019) shows that faulting started ~5 Ma later at 13.9±0.8 Ma. The age difference and the distance of 130 km between the two sites indicates that rifting and normal faulting propagated northward at an average rate of ~25 km/Myr. As this rate is similar to the Miocene convergence rate between India and south Tibet, we argue that the under-thrusting of India beneath Tibet has exerted an important control on the propagation of rifts in south Tibet.
References
Wolff, R., Hetzel, R., Hölzer, K., Dunkl, I., Xu, Q., Anczkiewicz, A.A., Li, Z. (2022). Rift propagation in south Tibet controlled by underthrusting of India: A case study at the Tangra Yumco graben (south Tibet). J. Geol. Soc. Lond., https://doi.org/10.1144/jgs2022-090.
Wolff, R., Hetzel, R., Dunkl, I., Xu, Q., Bröcker, M. & Anczkiewicz, A.A. (2019). High-angle normal faulting at the Tangra Yumco graben (southern Tibet) since ~15 Ma. J. Geology, 127, 15–36, http://doi.org/10.1086/700406.
How to cite: Hetzel, R., Wolff, R., Hölzer, K., Dunkl, I., Xu, Q., Anczkiewicz, A., and Li, Z.: Rift propagation in south Tibet controlled by under-thrusting of India: A case study at the Tangra Yumco graben (south Tibet), EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-1407, https://doi.org/10.5194/egusphere-egu23-1407, 2023.
