青藏高原隆升三阶段模型的数值模拟  

NUMERICAL SIMULATION OF THE THREE-STEP UPLIFT MODEL OF THE TIBET PLATEAU

作　　者：傅容珊[1,2] 黄建华[1,2] 李力刚 常筱华[3] 

机构地区：[1]中国科学技术大学地球和空间科学系 [2]第三世界科学院中国科学技术大学地球科学和天文学高级研究中心,合肥230026 [3]中国科学技术大学化学系

出　　处：《地学前缘》2000年第4期588-596,共9页Earth Science Frontiers

基　　金："攀登计划"资助项目 (970 2 310 3);"973"资助项目!(G19980 40 7)

摘　　要：研究表明 ,青藏高原的隆升不仅是印度板块和欧亚板块碰撞的结果 ,它同时受到高原下部地幔物质运移以及地幔和岩石层之间耦合作用的影响。文中以青藏高原隆升三阶段模式(BCCM )为基本模型 ,对在印度板块向北推移、挤压而导致的高原隆升演化的数值模拟结果进行处理。处理中考虑了与抬升过程相应的剥蚀过程 ,同时还考虑在高原演化的后期大约 8～10Ma时发生的下伏岩石层底部的对流搬离 (convectiveremoval)而导致的隆升作用。结果表明 ,模型描述的青藏高原隆升演化过程和观测资料有较好的吻合 ,同时显示高原下部岩石层的对流搬离可能是最近 8～ 10Ma以来高原整体隆升的主导机制。The study on the global tectonics and mantle dynamics shows that the Tibet Plateau uplift is not only the consequence of the collision between the India and Eurasia plates, but also the consequence of the interaction and coupling of the lithosphere and its underlying mantle in this region. The three\|step uplift model of the Tibet Plateau—Break off uplift-Compression uplift-Convection uplift Model(BCCM)—is to be simulated with a numerical model in this paper. The continental lithosphere of the East Asia is regarded as a continuum in a power law rheology. It lays on a relatively soft upper mantle and limited in a trapezoid geological frame. The movement of the Indian Plate at the rate of 5cm/a is assumed to be the main driving force to compress the plateau uplift and through out the passed 40 Ma. The uplift caused by the subductive continental crust break off and the uplift generated by the convective removal of the bottom of the plateau's lithosphere are considered to involve in the first and third stage of the Tibet Plateau's uplift. The results show that the modeled topography and the time dependents of the plateau's uplift can fit the observed patterns of this region in space and time very well. The convective removal of the bottom of the plateau's lithosphere is the main driving mechanism of the rapid uplift of the Tibet plateau in the period 8～10 Ma. The results also indicate that the process of the plateau's uplift is constrained by many factors such as the boundary conditions, the dynamical parameters of the continental lithosphere and the erosion rate as well.

关 键 词：青藏高原 隆升 地幔 数值模拟 岩石层 演化 BCCM 

分 类 号：P542.1[天文地球—构造地质学]