摘要
通过有限元数值模拟的方法,利用物理接触模型模拟断裂的非连续运动,计算GPS观测结果约束下天山的地壳运动变形,探讨天山东西部差异性地壳缩短的动力学机制。研究结果表明:天山现今地壳运动方向基本为NNE—NE向,运动速度由西南往北、往东逐渐减小;在活动断裂两侧,地壳的运动状态没有大的跳变;天山现今地壳构造应力场以近南北向挤压为主,这种应力环境导致地壳发生与之相应的近南北向缩短变形;受到山体内部块体几何形态和力学性质差异的影响,天山的地壳变形并不均匀,而且地壳缩短的主方向在东西部出现微小变化:中部为近N—S向,往西偏为NNW向,往东偏为NE向;塔里木盆地的顺时针旋转导致它对天山的挤压强度由西向东逐渐减弱,在这种西强东弱的不对等挤压作用下,天山便呈现出由西向东逐渐减弱的差异性地壳缩短变形特征。
The current crustal deformation of the Tianshan Mountain constrained by the GPS observation was analysed through FEA numerical method,using physical contact model to approach the discontinuous motion of faults.And the dynamic mechanism of crustal shortening with differences in the east and west of the Tianshan Mountain was discussed.The results indicate that the present-day crustal moving direction is generally NNE—NE in the Tianshan Mountain,with decrease of the velocity gradually from southwest to north and east.The state of crustal movement doesn＇t change abruptly at the two sides of faults.The current crustal tectonic stress field in the Tianshan Mountain is mainly compressed in nearly N—S,resulting in the crust shortening in nearly N—S as well.The crustal deformation of the Tianshan Mountain is not symmetrical influenced by the differences of the geometrical configurations and mechanical properties of the tectonic blocks.The principal direction of crustal shortening is nearly N—S in the middle,deflecting tinily to NNW in the west and NE in the east.Through analysis,it is thought that the clockwise rotation of the Tarim Basin causes the extrusion strength of the basin against the Tianshan Mountain descend gradually from west to east.With this kind of asymmetric extrusion effect charactered by strong-west and weak-east,the characteristic of crustal shortening deformation is that the difference of the deformation measurement decrease gradually from west to east in the Tianshan Mountain.
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2011年第9期2754-2762,共9页
Journal of Central South University:Science and Technology
基金
高等学校博士学科点专项科研基金资助项目(200805331115)
湖南省研究生科研创新项目(CX2010B051)
国家自然科学基金资助项目(40874048)
关键词
天山
地壳变形
接触模型
数值模拟
不连续运动
Tianshan Mountain
crustal deformation
contact model
numerical modeling
discontinuous motion
