印度-欧亚板块碰撞对南海形成的影响研究: 一种数值模拟方法

中国南海新生代处于欧亚板块、印度-澳大利亚板块和太平洋板块相互作用的交汇处,其形成演化受三大板块复杂动力学过程和相互间作用所制约,尤其是中始新世印度板块同欧亚板块之间的“硬”碰撞及随后的楔入的影响.利用FLAC软件对该次碰撞对南海形成效应进行了模拟,模拟结果表明在模型东-东南边界为自由边界和考虑太平洋向欧亚板块的俯冲作用的支持应力边界条件两种情形下,均能引起构造物质或地幔流向南东、南逃逸,在南海地区产生足够的侧向挤出和南北向的剪切,从而在该地区导致广泛的南北向拉张,这些极有利于南海的打开.

Study on the Effects of the India-Eurasia Collision on the Formation of the South China Sea: a Numerical Simulation Approach

The South China Sea ( SCS ) is located in the junctions of the Eurasia plate, India- Australia plate and Pacific plate in the Cenozoic, so the formation and evolutions of it were determined by the kinematic behaviours and interactions between all the three plates, especially the impacts of the India-Eurasia collision and the subsequent penetration of the India Plate into the Eurasia plate in the middle Eocene. The effect of this collison on the formation of the SCS was simulated by using the FLAC package. Under the two scenarios with an east-southeast free boundaries condition and the supported boundary condition of the subduction of Pacific plate under the Eurasia plate, the modeling results all indicate the tectonic transport escape eastsouthward and southward, which can result in the sufficient extrusion and N-S shearing, thus leading to that the broad N-S horizontal extension in the SCS region. All these factors are very favorable to the opening of the SCS.