The rheological structure of the East Asia continent is the key to understanding its broad, heterogeneous, and intense Cenozoic deformation. Based on a refined three-dimensional thermal structure of the lithosphere in this region and the latest strain rate data, we derived a model of the rheological structure of the East Asian continental lithosphere. The strength envelopes, defined by the yield strength of frictional, fractural, and plastic creep, are constrained by the lithological stratification based on previous studies and the depth distribution of earthquakes. The results show large vertical and lateral variations of lithospheric strength in the East Asian continent. A weak lower crust with low effective viscosity is ubiquitous. The rheological structure agrees with the jelly sandwich model in cratons, where the mantle lithosphere is relatively strong. The Tibetan Plateau has the weakest lower crust, with its effective viscosity ranging from 1019 to 1020 Pa∙s. Its mantle lithosphere is weakened by relatively high temperature; hence, its rheological structure can be described by the crème brûlée model. The lithospheric scale faults and suture zones in and around the Tibetan Plateau, with low strength or viscosity, correspond to the banana split model. The strength of the lithosphere in the Tibetan Plateau and other zones of active Cenozoic tectonics mainly derive from the crust, while the strength of the cratonic lithosphere is dominated by that of the mantle lithosphere. The rheological heterogeneity controls the lateral growth of the Tibetan Plateau and the widespread and differential deformation in the East Asian continent.

中文翻译：

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东亚大陆岩石圈的流变结构


东亚大陆的流变结构是理解其广泛、非均质和强烈的新生代变形的关键。基于该地区岩石圈的精细三维热结构和最新的应变率数据，我们推导出了东亚大陆岩石圈的流变结构模型。强度包络线由摩擦、分裂和塑性蠕变的屈服强度定义，受基于先前研究和地震深度分布的岩性分层的约束。结果显示，东亚大陆岩石圈强度的垂直和横向变化很大。低有效粘度的弱下层外壳无处不在。流变结构与克拉通中的果冻夹层模型一致，其中地幔岩石圈相对较强。青藏高原的下层地壳最弱，其有效粘度在 1019 至 1020 Pa 之间。它的地幔岩石圈因相对较高的温度而减弱;因此，它的流变结构可以用 Crème Brûlée 模型来描述。青藏高原及其周边地区的岩石圈尺度断层和缝合带，强度或粘度较低，对应于香蕉分裂模型。青藏高原和其他活跃的新生代构造带的岩石圈强度主要来自地壳，而克拉通岩石圈的强度则以地幔岩石圈的强度为主。流变异质性控制了青藏高原的横向生长和东亚大陆的广泛和差异变形。