森格藏布河谷盆地第四纪地貌发育和环境演变

森格藏布河谷盆地自第三纪早期即具雏形,后经数次明显的差异性升降运动,奠定了该盆地的地貌格局。在外营力的持续作用下,形成了丰富多彩的地质地貌类型。本文按沉积——地貌表现划分,将盆地内分为四个大地质地貌单元,共十五个小区。自盆地形成以来,其环境的变化主要受控于全球性的气候变化和整个青藏高原的上升速度及幅度,而盆地内的差异性升降运动对环境的影响相对微弱。

THE LANDFORM DEVELOPMENT AND ENVIRONMENTAL EVOLUTION IN SINGE-ZANGPU VALLEY BASIN

Singe-Zangpu valley basin,having changed into land in early Tertiary,formed am embryonic form owing to different rising range of fault blockmovements. In late Miocene, a strong tectonic movement established thegeomorphologic basis of the basin, making Eogene strata change form andrise. Another strong tectonic movement at the end of Lower Pleistocenedeceded the modern geomorphologic pattern of the inner area of the valleybasin, with a small series of faults which enriched the landform. In fact,the tectonic movements have never stopped in the area, it only showsfaint in rest times. The environment change in Singe-Zangpu valley basin has mainly beencontrolled by the evolution of Qinghai-Xizang Plateau. Relatively, thetectonic movements have faintly affected the environment.According to thedeposit recorded from 4600aB. P. to nowadays, the climate has continueddry and cold, and probably willbe aggravated in the future. The studiedresult on modern landform of the basin shows it is divided into 4 units(containing 15 lower grades) by deposit-landform manifestation.