黄河兰州谷地新构造运动的初步研究

通过分析新构造运动在黄河兰州谷地的表现,证明自上新世末以来本区新构造运动强烈,相继发生过3次主要构造事件,制约和影响黄河兰州谷地的形成、发育及环境演变。新构造运动以脉动式整体抬升和差异式断块运动的方式活动,使本区自2.4Ma以来上升约800m。由于特定的地貌位置和特殊的区域地质构造,本区新构造运动完全受制于青藏高原阶段性强烈隆起。

NEOTECTONICS OF THE YELLOW RIVER VALLEY IN LANZHOU

Based on an analysis of the neotectonic evidemnce from fault movement, ter-race development,river channel shifts, drainage patterns and seismic activities inthe Yellow River valley in Lanzhou,it is found that since the end of the Pliocenethe neotectonic movement in the area has been intense. Three main tectonic e-vents occurred one of after anothr at 2.4 Ma B. P.,1.6 Ma B. P. and 0.16 fo 0.5MaB. P, which restricted and affected the dynamic process of landform and drain-age formation and development and environmental evolution. During the Quaternary the neotectonic movement was superimposed by dif-ferential block movement on the basis of the whole pulsatony uplift. Calculation in-dicates that the area has uplifted about 800 m since 2.4 Ma B. P. and that theheight of the terminal pliocene planation surface should be 936--1,000 m .A compar-ison between the neotectonics of the Lanzhou area and that of the Qinghai-Tibetplateau shows that the main tectonic events and modes of the neotectonic move-ment in the area are essentially consistent with three intense uplift periods anduplift modes of the Qinghai-Tibet plateau. Because of the special geomorphologicaland tectonic settings, the neotectonics of the area were entirely controlled by thestage-stage uplift of the Qinghai-Tibet plateau. It may be considered from thisthat the intense uplift of the Qinghai-Tibet plateau is the "drive" of the neotec-tonic movement on the plateau itself. and its adjacen? areas.