青藏高原的现今地壳活动性

古近纪以来,印度板块与欧亚大陆的碰撞和持续的俯冲作用,造成了青藏高原强烈的陆内变形,引起了古造山带的复活;同时也使高原前陆盆地和内部的一些中小型盆地内数百米至数千米厚的新生代地层发生褶皱和冲断,遍布全区的逆冲推覆构造、走滑断裂和活动褶皱,在区域性的北东—南西向的构造应力作用下,导致高原地壳缩短加厚和整体向东滑移.高原的抬升是整体地、间歇性地、不均速地隆升.它经历了古近纪缓慢抬升—新近纪末至更新世快速抬升—全新世地壳振荡运动频繁的三个阶段.自7Ma至今,青藏高原累计抬高了3000~3500m,喜马拉雅山从古地中海崛起以来,至少上升了5000m.现代地热、地震发生,至今没有停止活动.

Present Crustal Activity Tibetan Plateau

The collision between Indian plate and Eurasian continent and its continuous subduction have resulted in severe intra-continental deformation in Tibetan plateau since the Paleogene period, leading to a revival of the paleo-orogenic belt, which, in turn, making the Cenozoic strata （hundreds to thousands of meters in thickness and located in foreland basins and in middle-to-small sized basins of the plateau） be folded and thrust. Further more, thrust nappe structures, strik-slip faults, and active folds all over the study area make the crust shortened and eastward slipped as a whole under the NE-SW structural stress. The uplift of the plateau as a whole is discontinuous and uneven, undergoing three stages： a slow uplift in Paleogene, a fast uplift from the end of Neogene to Pleistocene epoch, and a frequent crust oscillatory movement in Holocene epoch. The Tibetan plateau has been uplifted by 3 km to 3.5 km during the last 7 Ma and the Himalaya uplifted by at least 5 km since its rising from the lower mediterranean. In addition, geothermal activity and earthquake keep frequently taking place.