Salt basins often exhibit a shelf/slope region of extension and a deeper domain of contraction. The up-slope normal faults in such salt tectonics systems are often associated with the pinch-out edge of the buried salt layer. Although the spatial correlation between the normal faults and the salt pinch-out was previously observed, the mechanism was not fully explained. The Levant basin, which is a young and mildly deformed salt basin with a relatively thin overburden, provides an opportunity to analyze a simple salt tectonics system driven by basin margin tilt, and the formation of the normal faults. This work presents analytical and numerical modeling of the coupled viscous salt and overlying visco-plastic sediment layer. Results suggest the viscosities of both the sediment overburden and salt, as well as their thicknesses, control the deformation of the coupled layers. The visco-plastic deformation mechanism explains quantitatively the position of faulting and observations of the temporal evolution of brittle deformation in the Levant basin margin. It predicts that the largest stress in the overburden arises above the salt edge, driving normal faulting at that location. Our model also places quantitative constraints on the effective viscosity of the overburden (>2 × 10²⁰ Pa s), which is consistent with experimentally-determined creep laws. Our results contribute to the understanding of halokinematics in salt basins during the early stages of deformation and will allow better assessment of geological hazards related to salt related deformation.

中文翻译：

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通过倾斜启动盐构造：倾斜盐层和上覆脆性沉积物之间的粘性耦合

盐盆地通常表现出一个延伸的陆架/斜坡区域和更深的收缩区域。这种盐构造系统中的上坡正断层通常与埋藏盐层的尖灭边缘有关。尽管以前观察到正断层和盐分尖灭之间的空间相关性，但并未完全解释其机制。黎凡特盆地是一个年轻的、轻度变形的盐盆地，覆盖层相对较薄，为分析盆地边缘倾斜驱动的简单盐构造系统和正断层的形成提供了机会。这项工作提出了耦合粘性盐和上覆粘塑性沉积层的分析和数值模拟。结果表明沉积物覆盖层和盐的粘度，以及它们的厚度，控制耦合层的变形。粘塑性变形机制定量地解释了黎凡特盆地边缘的断层位置和脆性变形时间演化的观察结果。它预测上覆地层中的最大应力出现在盐边上方，从而推动该位置的正常断层。我们的模型还对覆盖层的有效粘度 (>2 × 10²⁰  Pa s)，这与实验确定的蠕变定律一致。我们的研究结果有助于了解变形早期盐盆地中的盐运动学，并将有助于更好地评估与盐相关变形相关的地质灾害。