Abstract The Mesozoic African rift system is an important continental rift system related to the Central African Shear Zone. While several geological models have been discussed, the mechanism of the Mesozoic African rift system is still unclear. One model proposed that the mechanism of the Mesozoic African rift system was inherited from the Benue Trough, which is a failed arm of the Guinea triple junction. Other models suggested that the mechanism of the Mesozoic African rift system could be clarified by the spreading of the Atlantic and weak lithospheric zones, such as the Pan-African suture zone. In this research paper, we create a shell model that considers spherical curvature, the heterogeneous structure of the African basement framework, and a combination of the upwelling St. Helena plume and seafloor spreading. The calculation of the model is solved through the finite element software ANSYS, and the modeling results match the actual geological evidence. In this study, nine other models are created with altered rock parameters or boundary constraints and compared to the original model to examine the influence of these factors. Compared to the nine comparative models, the original model best reflects the calculated results, which indicates that the coupling of the St. Helena mantle plume and ocean-ridge spreading caused the initial lithospheric rifting at ∼130 Ma and that the heterogeneities within Africa did not affect the extension direction of the rift basin but did influence the location of the rift basin.

中文翻译：

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中生代非洲裂谷系统的机制：古应力场建模

摘要 中生代非洲裂谷系是与中非剪切带相关的重要大陆裂谷系。虽然已经讨论了几种地质模型，但中生代非洲裂谷系统的机制仍不清楚。一个模型提出中生代非洲裂谷系统的机制继承自贝努埃海槽，这是几内亚三联交界处的一个失败臂。其他模型表明，中生代非洲裂谷系统的机制可以通过大西洋和弱岩石圈带（如泛非缝合带）的扩张来阐明。在本研究论文中，我们创建了一个壳模型，该模型考虑了球面曲率、非洲基底框架的异质结构以及上升流的圣赫勒拿羽流和海底扩张的组合。模型计算通过有限元软件ANSYS求解，建模结果与实际地质证据相符。在这项研究中，创建了其他九个模型，其中改变了岩石参数或边界约束，并与原始模型进行了比较，以检查这些因素的影响。与9个对比模型相比，原始模型最能反映计算结果，表明圣赫勒拿地幔柱和洋脊扩张的耦合导致了~130 Ma的初始岩石圈裂谷，非洲内部的非均质性没有影响裂谷盆地的伸展方向，但确实影响了裂谷盆地的位置。其他九个模型使用改变的岩石参数或边界约束创建，并与原始模型进行比较以检查这些因素的影响。与9个对比模型相比，原始模型最能反映计算结果，表明圣赫勒拿地幔柱和洋脊扩张的耦合导致了~130 Ma的初始岩石圈裂谷，非洲内部的非均质性没有影响裂谷盆地的伸展方向，但确实影响了裂谷盆地的位置。其他九个模型使用改变的岩石参数或边界约束创建，并与原始模型进行比较以检查这些因素的影响。与9个对比模型相比，原始模型最能反映计算结果，表明圣赫勒拿地幔柱和洋脊扩张的耦合导致了~130 Ma的初始岩石圈裂谷，非洲内部的非均质性没有影响裂谷盆地的伸展方向，但确实影响了裂谷盆地的位置。