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采用I2VIS有限差分方法,模拟了东海陆架盆地南部中生代的盆地演化过程。数值模型的构建主要基于研究区域内现有的地震剖面、测井、层析成像等资料获得的中生代地层结构特征。根据模拟结果,对比已知的岩浆侵入特征和断裂组合规律,定量分析了在不同边界条件下,各阶段盆地演化的岩浆断裂及沉积特征,并探讨了影响盆地构造特征的主要因素。得出以下认识:(1)通过改变模型的边界条件发现,层状含水地幔在拉伸环境下,会对地壳结构造成破坏,中生代东海陆架盆地区域性伸展不是盆地演化过程的唯一主控因素。(2)东海陆架盆地中生代的成盆过程及属性与中生代时期上地幔物质流动有着密切关系。(3)中生代的地幔物质流动导致的大规模岩浆事件很可能作用于闽江凹陷之下,由此导致了闽江凹陷的进一步抬升,形成现今的斜坡带,而基隆凹陷进一步沉降,形成凹陷的沉积中心。基于以上结论,认为区域性伸展和上地幔物质流动导致的岩浆上涌两大因素共同控制下,影响了东海陆架盆地南部中生代的演化。
The I2VIS finite difference method was used to simulate the Mesozoic basin evolution in the southern East China Sea shelf basin. The construction of the numerical model is mainly based on the Mesozoic stratigraphic structure characteristics obtained from the existing seismic profiles, well logs and tomographic data in the study area. According to the simulation results, the magmatic intrusive characteristics and fault combination rule are compared, and the magmatic faults and sedimentary characteristics of various stages of basin evolution under different boundary conditions are quantitatively analyzed. The main factors affecting the tectonic features of the basin are also discussed. The following conclusions can be obtained: (1) By changing the boundary conditions of the model, it is found that the stratified aquifer can destroy the crustal structure under the tensile environment. The regional extensibility of the Mesozoic East China Sea shelf basin is not the only dominant factor of the basin evolution. (2) The Mesozoic process and properties of the Mesozoic in the East China Sea shelf basin are closely related to the material flow of the upper mantle in the Mesozoic. (3) Large-scale magmatic events caused by the Mesozoic mantle material flow are likely to act under the Minjiang Depression, leading to further uplift in the Minjiang Depression and the formation of today’s slope zone, while the Keelung Depression further subsides to form a depression Deposition Center. Based on the above conclusions, under the common control of the two factors of regional extension and magmatic upwelling caused by upper mantle material flow, the evolution of Mesozoic in the southern East China Sea shelf basin is affected.