Pattern of Modern Denudation in the Longmen Shan, Eastern Tibetan Plateau: Tectonic Controls on Focused Erosion along the Plateau Margin
详细信息
- 责任者：Wen Li (Key Laboratory of Continental Collision and Plateau Uplift ; Institute of Tibetan Plateau Research ; Chinese Academy of Sciences ; Beijing 100101 ; China) ; Liu Jing
- 刊名：Quaternary Sciences
- 出版年：2012
- 卷期：32(5)
- 关键词：活动构造 ; active tectonics ; 侵蚀速率 ; erosion rates ; 四川 ; Sichuan Province
- 页码：p.968-985
- 图表：illus., 110 refs.
- 分类号：0300
- isbnNo：CN11-2708/P
摘要
The authors use river sediment load data to characterize the magnitude and spatial pattern of modern denudation across the Longmen Shan margin of the Tibetan Plateau.Precipitation influence in modern denudation is manifested in the temporal domain by annual and seasonal fluctuations in accord with the variations in monsoon intensity.Majority of sediment is transported in large storms,particularly 80%～90% of suspended sediments delivered during June-September of monsoonal rain.Enhanced denudation in a 50 km-wide stripe in the hanging wall of the Pengguan fault may represent an erosional balance to tectonic uplift and advection above the ramp-up of decollement at depth,connecting to the Pengguan fault.Denudation of 0.5～0.8 mm/a above a ca.20° NW-dipping ramp,as structurally inferred by a critical taper wedge model,implies a horizontal shortening rate of 1.4～3.0 mm/a,consistent with that measured by GPS geodesy.This suggests that the Longmen Shan margin may have reached a flux steady-state.The consistency also indicates that the topography in the Longmen Shan could be maintained entirely by upper crustal shortening.
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