Continental rifts normally initiate within previously deformed lithosphere and thus their evolution and architecture can be largely controlled by inherited weak zones in the pre-rift crust. Here, we quantify the role of the strength and obliquity of pre-existing crustal-scale weak zones in the evolution of continental rift systems. We use a 3D numerical geodynamic model to assess strain localization, associated fault development, and rift segmentation during the early stages of tectonic extension. We find that both the strength and obliquity of the weak zones significantly influence the patterns of strain localization. A pre-existing very weak zone with low obliquity can promote the development of continuous and long-lived border faults parallel to the rift axis. Conversely, a comparatively strong weak zone with high obliquity leads to a staggered en-echelon rift geometry that lacks rectilinear laterally persistent strain localization. Furthermore, we find that rift obliquity and weak zone strength may modulate rift fault length, throw, and azimuth. These results provide new and compelling insights into the structure and evolution of natural active rifts that develop within orogenic basement terranes.

中文翻译：

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预先存在的薄弱区强度对裂谷几何形状和应变定位的影响


大陆裂谷通常始于先前变形的岩石圈内，因此它们的演变和结构在很大程度上可以受到裂谷前地壳中遗传的薄弱带的控制。在这里，我们量化了预先存在的地壳尺度薄弱带的强度和倾斜度在大陆裂谷系统演化中的作用。我们使用 3D 数值地球动力学模型来评估构造延伸早期的应变定位、相关断层发展和裂谷分割。我们发现薄弱区的强度和倾斜度都显着影响应变定位的模式。预先存在的低倾角非常薄弱的带可以促进平行于裂谷轴的连续和长寿命边界断层的发展。相反，具有高倾斜度的相对较强的弱区会导致交错的梯队级裂谷几何形状，缺乏直线横向持续应变定位。此外，我们发现裂谷倾斜度和弱区强度可能调节裂谷断层长度、投掷和方位角。这些结果为造山基底地层中形成的天然活动裂缝的结构和演变提供了新的、令人信服的见解。