青藏高原北部NNW向构造活动方式及形成年代

ACTIVITY WAYS AND FORMATION AGE OF THE NNW TECTONICS IN THE NORTHERN TIBET PLATEAU

对青藏高原北部ＮＮＷ向构造的地质地貌组合特征、活动方式及形成年代等问题进行的研究表明，ＮＮＷ向构造在地貌上由西向东表现为隆、拗相间排列的构造格局。其中ＮＮＷ向活动断裂依次发育在隆起带的东缘，形成伴有褶皱构造的逆冲－挤压构造带。拗陷带则由一系列位于隆起带之间的压陷性盆地带组成。ＮＮＷ向构造活动强烈，特别是在第四纪中、晚期以来，它们不仅制约着青藏高原北部区地质地貌的发生和发展，而且还在地震活动及强震孕育和发生过程中扮演着重要的角色，ＮＮＷ向隆起从第三纪末期至第四纪初期开始发育，但大规模隆起发生在第四纪中更新世以来。

Based on the recent field work,we analyze the geological geomorphic characteristics,activity ways and formation ages of the NNW tectonics developed in the northern Tibet plateau The results indicate that this NNW tectonics exists in all the area from north to the east of Kunlun moutain to the Hexi corridor In geomorphology it represents the structural configuration of uplift downsink jaxuposition from east to west The NNW faults developed in the east margin of the uplift zone as fold companion thrust compression zone The downsink zones are composed of a series of depressive basins located between middle and late Quaternary,highly active which not only control the formation and development of the geomorphic feathers but also play vital roles to seismic activity and orogeny and occurrence of strong events The NNW tectonics began to develop from the late Tertiary to early Quaternary and uplift of large scales happened from middle Pleistocene