Characteristics of Nappes and Segmentation of the Longmen Mountains Thrust Belt, Western Sichuan Basin, China
- 1 School of Energy Resources, China University of Geosciences, Beijing, China
- 2 Hangzhou Institute of Petroleum Geology, Petro China, Hangzhou, China
- 3 Research Institute of Petroleum Exploration & Development, Petro China, Beijing, China
- 4 Jidong Oilfield Branch Company, Petro China, Tangshan, China
- 5 State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing, China
Abstract
In order to reveal the nature of the segmentation of Longmen Mountains Thrust Belt caused by the three nappes (Jiaoziding, Jiudingshan, and Baoxing Nappe), several methods are applied in this paper, including field investigation, seismic explanation and balanced crossed section, etc. Results of research reveal that nappes in Longmen Mountains vary in geometry, kinematics, and dynamics. Jiaoziding Nappe has generally behaved in a ductile manner, whereas Jiudingshan Nappe has been rigid, and the rheology of Baoxing Nappe has been intermediate between that of the other two nappes. The development of nappes has resulted in tectonic segmentation of Longmen Mountains: the main structural style of the northern segment is thrust faulting, with Jiaoziding Nappe representing a giant syncline. Given its ductility, it absorbed lots of stress, with the least amount of tectonic shortening in the SE part of the nappe. In the middle segment, the deformation is controlled by the rigid Jiudingshan Nappe, whose frontal area records lots of tectonic shortening. Deformation in the southern segment is intermediate in character between that of the other two segments, characterized by horizontal zonation, as demonstrated by fault development, and vertical stratification, which indicates that fault development was controlled by lithology.
- Chen, S.F., Wilson, C.J.L., Luo, Z.L., et al. (1994) The Evolution of the Western Sichuan Foreland Basin, Southwestern China. Journal of Southeast Asian Earth Sciences, 10, 159-168. https://doi.org/10.1016/0743-9547(94)90016-7
- Dirks, P.H.G.M., Wilson, C.J.L., Chen, S., et al. (1994) Tectonic Evolution of the NE Margin of the Tibetan Plateau; Evidence from the Central Longmen Mountains, Sichuan Province, China. Journal of Southeast Asian Earth Sciences, 9, 181-192. https://doi.org/10.1016/0743-9547(94)90074-4
- Jia, D., Chen, Z.X., Jia, C.Z., et al. (2003) Structural Features of the Longmen Shan Fold and Thrust Belt and Development of the Western Sichuan Foreland Basin, Central China. Geological Journal of China Universities, 9, 402-410. (In Chinese with English Abstract)
- Yang, K.M., Zhu, T. and He, L. (2003) Structural Characteristics and Exploration Potential of the Thrust Block in Longmenshan. Petroleum Geology & Expeximent, 25, 685-694. (In Chinese with English Abstract)
- Zhou, J.W., Zeng, Q., Xu, S.Q., et al. (2005) Research on Deformation Characteristics of the Nappe Structural Belts in the North Section of Longmen Mountains. Natural Gas Industry, 25, 66-71. (In Chinese with English Abstract)
- Jia, D., Wei, G.Q., Chen, Z.X., et al. (2006) Longmen Shan Fold and Thrust Belt and Its Relation to the Western Sichuan Basin in Central China: New Insights from Hydrocarbon Exploration. AAPG Bulletin, 90, 1425-1447. https://doi.org/10.1306/03230605076
- Li, S.B., Chen, Z.G. and Chen, H.D. (2005) Oil & Gas Geology and Evaluation on the favorable Areas. Southwest Division, SINOPEC. (in Chinese)
- Liu, S. (2006) Structural Characteristics of the Thrust Fold of Foreland—A Case Study of the Thrust Fold at Micang and Longmen Mountains. Ph. D. Thesis, Institute of Geology, China Earthquake Administration, Beijing. (In Chinese with English Abstract)
- Jin, W.Z., Tang, L.J., Yang, K.M., et al. (2010) Segmentation of the Longmen Mountains Thrust Belt, Western Sichuan Foreland Basin, SW China. Tectonophysics, 485, 107-121. https://doi.org/10.1016/j.tecto.2009.12.007
- Jin, W.Z., Tang, L.J., Yang, K.M., et al. (2009) Transfer Zones of Longmen Mountain Thrust Belt, SW China. Geosciences Journal, 13, 1-14. https://doi.org/10.1007/s12303-009-0001-9
- Wang, W.F., Qing, Y.B., Zhu, C.Q., et al. (2015) Geological Characteristics of Transverse Faults and Its Earthquake-Controlling Function along the Longmenshan Fault Zone. Journal of Seismological Research, 38, 243-251 (In Chinese with English Abstract)