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根据现有的地质和地球物理资料以及山区和平原的动力学观点,利用青藏高原北东向的简化构造剖面(全长约2000公里,深约80公里),对其当前的形变和应力状态进行了有限单元分析。数值结果表明,印度板块运动是扰动重力均衡和导致侧向密度差异的驱动力,但是由于均衡调整所产生的水平压应力才是高原上升和发生大地震的机制;还表明应力集中的必备条件是主要断裂带的端部接近而不穿过低速层。 在相当于40公里深度的温度、压力条件下,二云母片麻岩的电导率测定,簿片鉴定和X光分析等都证实,由于白云母脱水所伴随的晶格破坏以及石英的热裂作用所造成的力学性质的弱化似是高原地壳低速层的形成机制,但是沿低速层的剪切运动则是增高这层温度的重要来源。
Based on available geophysical and geophysical data and the kinetic perspectives of the mountainous and plains, the northeastern simplified structural profile of the Qinghai-Tibet Plateau (total length of about 2000 km and depth of about 80 km) is used to analyze the current deformation and stress state Finite element analysis. The numerical results show that the plate movement in India is the driving force for disturbing the gravity balance and causing the lateral density difference. However, the horizontal compressive stress generated by the equilibrium adjustment is the mechanism for the plateau rise and the occurrence of large earthquakes. It also shows the necessary conditions for stress concentration It is the end of the main fault zone that approaches without passing through the low velocity layer. Conductivity measurement, book identification and X-ray analysis of two mica gneiss at temperature and pressure equivalent to a depth of 40 km confirm that due to the lattice destruction accompanying the dehydration of muscovite and thermal cracking of quartz, The weakening of the mechanical properties may be the formation mechanism of the low-velocity crust in the plateau, but the shear movement along the low-velocity layer is an important source of increasing the temperature of the crust.