印度-欧亚板块碰撞期间红河断裂带活动性的数值模拟研究

Numerical simulation of activity of Red-River Fault Zone during India-Eurasia collision

红河断裂带是一巨型走滑断裂带,在印度板块与欧亚板块碰撞过程中成为印支地块和华南地块之间相互运动的主位移带。通过有限差分数值模拟试验,结果表明,在碰撞期间,红河断裂带首先经历了左旋走滑运动,红河断裂带中央部分的左旋偏移量最大,达到约325km,印支地块向南东挤出,在5Ma BP后表现为右旋走滑,说明沿红河断裂带的剪切运动是红河断裂带西端与印度-欧亚碰撞边界之间距离的函数,随时间而减小并控制了印支地块与华南地块之间的相对运动。

The Red-River Fault Zone （RRFZ） is a huge strike-slip fault, which became a primary displacement zone between the Indochina Block and the South China Block in the process of the India-Eurasia collision. The results of numerical simulation by the finite difference method show that, during the India-Eurasia collision, the RRFZ first experienced huge left-lateral shearing, and the Indochina Block was extruded southeastwards. The whole left-lateral displacement was about 325km. Then it reversed to right-lateral shearing after 5 Ma BP. The style of shearing motion along the Red River Fault was a function of the distance between the fault and the India-Eurasia collision frontier, which decreased with time and controlled relative extrusion movement between the South China Block and the Indochina Block.