关键词: 内蒙古, 大青山, 呼和浩特断陷盆地, 剥蚀, 地壳均衡隆起

Abstract: The Daqingshan Mountains and its adjacent Huhehot fault basin, Nei Monggol, are the ideal area to study denudation and uplift. By means of morphomeric analysis and field observation, this paper provides evidence for arching deformation of four accordant summit levels aged in Oligcene, Miocene, Plicene, and Quaternary stream terrace flights. On the basis of the result of seismic surveying for the Huhehot basin, the average Cenozoic denudation and crustal isostatic uplift amounts are estimated to be 3 310m and 2 910m, respectively, for the Daqingshan Mountains. It is thus evident that the resulting relief lowering due to denudation after crustal isostatic uplift is really slight, only 400m. For the denudation of the Daqingshan Mountains, obviously strenthening with time resulted from the long term climatic change during the Cenozoic era. The crustal isostatic uplift is a principal regional deformation mechanism for the Daqingshan Mountains. First, the crustal isostatic uplift controls the Cenozoic landscape evolution history. Second, the rate of the crustal isostatic uplift of late Quaternary has been quicker from the western part to the eastern of the Daqingshan Mountains. And third, the amount of the Quaternary crustal isostatic uplift of the Daqingshan Mountains is greater than the Ordos'tectonic uplift by one order. A close coupling relation between denudation to lose gravity equilibrium and crustal isostatic uplift to restore gravity equilibrium runs through the Cenozoic land evolution history of the Daqingshan Mountains. The faulting has a different position before and after the establishment of the coupling relation. And the flexural isostatic has accommodated long term local differential movement on the fault zone.

Key words: Nei Monggol, Daqingshan Mountains, Denudation, Crustal isostatic uplift