张裂大陆边缘形成演化的数值模拟

本文在等黏态角落流模型的基础上，建立了上升离散地幔流场，将该流场作用于大陆岩石圈底部，能解释岩石圈减薄、裂解并最终形成海底扩张和张裂大陆边缘等一系列过程.数值模拟的结果表明，岩石圈在上升离散地幔流的作用下发生依赖于深度的伸展减薄，表现为不同深度的拉张因子不同，地表热流显著升高，热扰动引起的均衡调整造成地表沉降，同时热扰动造成岩石圈流变强度尤其是在变形中心处显著减小，脆性变形临界深度变浅，而韧性变形范围扩大.在上升离散地幔流的持续作用下最终导致大陆裂解，岩石圈地幔出露，形成海底扩张和张裂大陆边缘.

The numerical modeling of the formation and evolution of rifted continental margin

On the basis of the isoviscous corner flow model, we established upwelling divergent mantle flow field. When this flow field acts on the base of continental lithosphere, the deformation and thinning of continental lithosphere leading to breakup and the initiation of sea-floor spreading can be described. The numerical modeling results indicate that lithosphere behaves as depth-dependent stretching manifested as stretching factors from different depth are different, and the surface heat significantly increases in response to an upwelling divergent mantle flow. The isostatic adjustment due to the mantle flow-induced thermal disturbance leads to surface subsidence; meanwhile, the thermal disturbance reduces the rheological strength of lithosphere, especially at deformation center. The critical depth of brittle deformation is reduced and the range of ductile deformation becomes larger significantly. This deformation finally evolves into continental breakup, mantle exhumation, and the formation of sea-floor spreading and rifted continental margin under the continuing impact of upwelling divergent mantle flow.