论文部分内容阅读
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.
Longmenshan is the most varied mountain topography in the mountains around the Qinghai-Xizang Plateau.Using digital elevation models (DEM), the 3D residual surface method is used to recover the late Paleozoic ancient remnant surface DEM in the Longmen Mountains, We can obtain the denudation topography of the study area and then quantitatively estimate the surface eroded amount of the Late Cenozoic in the major river basins of the Qingyi River, the Minjiang River, the Tuojiang River and the Fujiang River.The results show that the total amount of surface erosion in the Late Cenozoic of Longmen Shan is 80 500 ~ 92.800km3. The contribution rate of erosion to the Longmenshan area in the Minjiang River Basin is about 33.9% -37.1%, followed by Fujiang (33.6% -38.4%) and Qingyi River (24.1% -31.9%), while the Tuojiang River Basin contributes 0.4% 0.6%. The rapid surface erosion caused by the secondary disasters such as the 2008 Wenchuan Earthquake was the main reason of the Late Cenozoic erosion in the Longmenshan orogenic belt on the eastern margin of the Qinghai-Tibet Plateau.