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There is a massive amount of geomorphic evidence for active tectonics in the Longmen Shan at the eastern margin of the Tibetan plateau.We have surveyed some typical geomorphic markers including the Wenchuan-Maowen,Beichuan-Yingxiu and Pengxian-Guanxian faults,terrace offsets, scarps,fault-controlled saddles,dextral shutter ridges,dextral channel offsets,graben,shatter belts, and pull-apart basins.Electron spin resonance(ESR) and thermoluminescence(TL) ages were obtained using silty sand taken from below the surface of the sediments.According to these data,we calculated the rates of thrusting and strike-slip,and the results indicate that Cenozoic tectonic shortening at the plateau margin is minor with the rate of thrusting less than 1.10 mm/a and the rate of strike-slipping less than 1.46 mm/a.The Longmen Shan is a zone of NNE-trending dextral shear with slip-dip ratio of 6:1-1.3:1.From NW to SE,the thrust component becomes smaller,whereas the strike-slip component becomes larger.
There is a massive amount of geomorphic evidence for active tectonics in the Longmen Shan at the eastern margin of the Tibetan plateau. We have surveyed some typical geomorphic markers including the Wenchuan-Maowen, Beichuan-Yingxiu and Pengxian-Guanxian faults, terrace offsets, scarps , fault-controlled saddles, dextral shutter ridges, dextral channel offsets, graben, shatter belts, and pull-apart basins. Electron spin resonance (ESR) and thermoluminescence (TL) ages were obtained using silty sand taken from the surface of the sediments . According to these data, we calculated the rates of thrusting and strike-slip, and the results indicate that Cenozoic tectonic shortening at the plateau margin is minor with the rate of thrusting less than 1.10 mm / a and the rate of strike-slipping less than 1.46 mm / a. Longmen Shan is a zone of NNE-trending dextral shear with slip-dip ratio of 6: 1-1.3: 1. From NW to SE, the thrust component becomes smaller, the strike-slip component becomes larger.