Abstract Widespread heterogeneities exist in the continental lithosphere, but their role in continental rifting is poorly understood. Here we investigate the influence of lithospheric heterogeneities on the pattern of continental rifting using 2D thermo-mechanical simulations. The heterogeneities are mainly manifest in a laterally inhomogeneous continental lithosphere, which has a cold west (CW) half and a hot east (HE) half. A series of experiments were performed to examine the effects of lithospheric thermal state, weak zones, and extension velocity on continental rifting. The results show that: (1) stretching of a CWH E lithosphere always leads to the formation of a wide rift at the HE side, while the CW side remains largely undeformed; (2) the presence of a weak zone in the CW lithosphere can cause a wide rift to form at the eastern side and a deep narrow rift to form synchronously at the western side; and (3) the lithospheric thermal state strongly affects the style of rifting and the lithospheric deformation mode. When the crust is extremely hot (TMoho = 900 ℃), a wide rift first develops at the HE side, which is followed by the formation of a narrow rift at the CW side. The extension velocity mainly affects the timing of rift formation but has no significant effect on the style of rifting. A number of rift basins have developed in the North China Craton (NCC) since the early Cenozoic in response to the retreat of the Pacific plate subduction. The eastern NCC is dominated by wide rifts, whereas the western NCC is dominated by narrow rifts. We suggest that the coexistence of these two types of rift in the NCC is the result of lateral lithospheric heterogeneities, which include pre-existing lithospheric weaknesses. The differences in the thermal and rheological states between the Eastern Block and Western Block of the NCC prior to extension were likely to cause the wide rifts at the east and the narrow rifts at the west.

中文翻译：

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岩石圈非均质性在大陆裂谷中的作用：对华北克拉通裂谷多样性的启示

摘要 大陆岩石圈存在广泛的非均质性，但对它们在大陆裂谷中的作用知之甚少。在这里，我们使用二维热机械模拟研究岩石圈非均质性对大陆裂谷模式的影响。非均质性主要表现在横向不均匀的大陆岩石圈中，该岩石圈具有西冷（CW）半部和东热（HE）半部。进行了一系列实验来检验岩石圈热状态、弱区和伸展速度对大陆裂谷的影响。结果表明：（1）CWH E 岩石圈的拉伸总是导致HE 侧形成宽阔的裂谷，而CW 侧基本未变形；(2) CW岩石圈弱带的存在会导致东侧形成宽阔的裂谷，西侧同时形成深而窄的裂谷；(3) 岩石圈热状态强烈影响裂谷类型和岩石圈变形方式。当地壳极热时（TMoho=900 ℃），HE 侧首先形成宽的裂谷，随后在 CW 侧形成狭窄的裂谷。伸展速度主要影响裂谷形成时间，对裂谷类型影响不显着。早新生代以来，为响应太平洋板块俯冲后退，华北克拉通（NCC）发育了多个裂谷盆地。华北克拉通东部以宽裂谷为主，华北克拉通西部以窄裂谷为主。我们认为，NCC 中这两种裂谷的共存是横向岩石圈非均质性的结果，其中包括预先存在的岩石圈弱点。华北克拉通东、西地块在伸展前的热流和流变状态的差异可能导致东侧裂谷变宽，西侧裂谷变窄。