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 and mark-in-cell technique is used to simulate the evolution of Meso- zoic basins in the southern part of the East China Sea Continental Shelf Basin. The numerical model was constructed based on the existing seismic profiles, drilling and tomographic data of the study area. Based on the simulation results, the magmatic intrusion and sedimentation during the basin evolution are quanti- tatively analyzed under different boundary conditions, and the main factors affecting the tectonic evolution of the basin are discussed. As the results, following conclusions are obtained. 1) The change of the boundary conditions for the models indicates that the stratified aquifer mantle will destroy the crustal structure under tensile environment, and the regional extension of the Mesozoic East China Sea Continental Shelf Basin is not the only master factor to the basin evolution. 2) Mesozoic basins are closely related to the material flow in upper mantle during the Mesozoic Era. 3) The large-scale magmatic events caused by the Mesozoic mantle flow are likely to affect the Minjiang Depression, leading the Depression turning to uplift, the formation of the present-day slope zone, and further settling of the Jilong Depression to become a depression center. The regional evolution and magma upwelling caused by the upper mantle flow have in- deed influenced the evolution of the Mesozoic basin in the southern part of the East China Sea Continental Shelf Basin.