Continental rifting is one of the fundamental tectonics of the Earth evolution while our current understandings on the dynamic mechanism of the strike-slip ones are relatively limited. Here, we have utilized three kinds of core-refracted shear waves (including PKS, SKKS, and SKS) and employed the shear-wave splitting technique to systematically investigate the azimuthal anisotropy of the upper mantle under the typical strike-slip Dead Sea rift. There are a total of 1,855 well-determined anisotropic measurements from 187 stations with dominantly N-S fast orientations. We have proposed a new model from a joint analysis of multiple newly available geophysical observations to interpret the resulting anisotropy as mainly due to the absolute-plate-motion-driven mantle flow deflected by the thick lithosphere of the eastern Arabian plate. Relatively larger splitting times are locally revealed at the rift zone and attributed to additional lithospheric anisotropy from the shearing-oriented melt pockets whose existence further induces complex anisotropy with slight difference of fast orientations between the upper and lower layer anisotropy. The overall rift-parallel fast orientations, when combined with the absence of low-velocity and hot thermal anomalies in the mantle transition zone, rule out the role of mantle plume or edge-driven convection in the rift development and further infer the Dead Sea rift to evolve in a passive mode.

中文翻译：

---

走滑死海裂缝下的偏转地幔流和剪切对齐的岩石圈熔体


大陆裂谷是地球演化的基本构造之一，而我们目前对走滑动力学机制的理解相对有限。在这里，我们利用了三种核心折射横波（包括 PKS、SKKS 和 SKS），并采用横波分裂技术系统研究了典型走滑死海裂谷下上地幔的方位各向异性。总共有来自 187 个站点的 1,855 个确定的各向异性测量值，这些测量以 N-S 快速方向为主。我们通过对多个新可用的地球物理观测的联合分析提出了一个新模型，以将产生的各向异性解释为主要由于绝对板块运动驱动的地幔流被阿拉伯板块东部厚厚的岩石圈偏转。在裂谷带局部揭示了相对较大的分裂时间，并归因于来自剪切导向熔体袋的额外岩石圈各向异性，其存在进一步诱导了复杂的各向异性，上下层各向异性之间的快速取向略有不同。整体裂谷平行快速取向，再加上地幔过渡区中没有低速和热热异常，排除了地幔羽流或边缘驱动对流在裂谷发展中的作用，并进一步推断死海裂谷以被动模式演化。