【摘要】 龙门山是青藏高原周边山脉中地形梯度变化最大的山脉.利用数字高程模型(digital elevation models,DEM),采用三维残余面法恢复龙门山晚新生代古残余面DEM,并与现代地形面做差值运算,得到研究区域的剥蚀量地形,进而定量估算青衣江、岷江、沱江和涪江主要水系流域晚新生代的地表剥蚀量.结果表明:龙门山晚新生代地表剥蚀总量为80 500~92 800km3;岷江流域对龙门山地区剥蚀量贡献率约33.9%~37.1%,其次为涪江(33.6%~38.4%)、青衣江(24.1%~31.9%),沱江流域贡献率为0.4%~0.6%;类似2008年"5·12"汶川地震的次生灾害引发的地表快速剥蚀,是青藏高原东缘龙门山造山带晚新生代地表剥蚀的主要原因.更多还原

【Abstract】 Longmen Shan located at the eastern margin of Tibetan Plateau represents the steepest gradient of the Tibetan Plateau edges.To assess the large-scale denudation volume in Longmen Shan,Late Cenozoic,surface denudation is quantitatively calculated along several large drainage basins such as Qingyijiang,Minjiang,Tuojiang,and Fujiang rivers by using digital elevation models(DEM)data,and residual surface method with paleo-residual surface DEM minus modern surface topography in this study.It is found that the Late Cenozoic denudation volume of upper reaches in Longmen Shan drainage basin is between 80 500 and 92 800km3.Minjiang River has the largest contribution ratio to denudation in Longmen Shan(33.9%-37.1%),followed by Fujiang(33.6%-38.4%)and Qingyijiang Rivers(24.1%-31.9%),and Tuojiang River has minimum contribution(0.4%-0.6%).A rapid erosional removal from the Longmen Shan by repeated great seismic events like the Wenchuan earthquake on May 12 th,2008,may be a main reason of the surface erosion in Late Cenozoic Longmen Shan along the eastern margin of Tibetan Plateau.更多还原