青藏高原—天山地区岩石层构造运动的地幔动力学机制

利用全球重力大地水准面异常、板块绝对运动及全球地震层析成像数据，计算了青藏高原—天山地区岩石层下部地幔大尺度对流格局以及此种尺度对流驱动下岩石层内应力场分布；同时，利用区域均衡重力异常数据反演青藏高原中、北部到天山地区上地幔小尺度对流模型．结果表明，大尺度的地幔物质运移过程可能驱动着中国大陆岩石层整体从西部以南北方向为主的运动转向东部地区以北东和南东方向的运动；而该区域上地幔小尺度上升流动支持了现代青藏高原和天山地区的抬升运动．提出和讨论了青藏高原隆升的“断离隆升—挤压隆升—对流隆升”三阶段模式，并探讨了大陆岩石层构造运动的地幔深部动力学背景．

STUDY OF THE MANTLE DYNAMICS OF THE LITHOSPHERE MOVEMENTS IN THE REGION FROM QINGHAI-XIZANG PLATEAU TO TIANSHAN MOUNTAIN

The structures and neotectonic movements of the lithosphere in the region from Qnghai-Xizang Plateau to Tianshan Mountain System have been inveshgared in this paper. Two scale mantle convection models are employed to explain the lithospheric dynamics of this region. One is a large scale mantle convection pattem, which is calculated by using the global geoid anomalies, plare absolute motions and mantle seismic tomography data set,and anather is a small scale convection model in the upper mantle of this region constrained on the data of the regional isostatic gravity anomalies. Comparing these models with the geophysical and geodetic observations shows that the large scale mande convechon may drive the lithosphere motions of the China continent from North-South direction in the west part to the North-East or South-East direction in the east part. Meantime, the small scale convection system in the upper mantle of this region may control the recent uplift movements of the Qnghai-Xizang Plateau and the Tianshan Mountain System. Furthermore, a three step uplift model of the Qinghai-Xizang Plateau: "uplift after break off-uplift with compression-uplift with small scale convechon" is to be proposed and the deep mantle dynamical background of the lithosphere movements in this region are to be discussed as well.