Abstract The complex geometry and tectonic evolution of the Saharan-Tunisian Southern Atlas strike-slip fault systems, North Africa, have not been investigated comprehensively to date. This paper proposes new conceptual models to better understand the structural styles along these intraplate fault zones. We use a multidisciplinary approach including field observations, geological mapping, stress analysis and seismic data to investigate the development and interaction of major strike-slip fault segments. The regional fault system is dominated by the E-W trending Biskra, Alima, Orbata, Bouhedma and Chotts basement faults that constitute the Principal Displacement Zones (PDZs). Our analyses and interpretations reveal that each PDZ has a typical dextral strike-slip architecture comprising multi-scale fault segments that are linked through dilational and contractional stepovers/bends. During Mesozoic times, under NE-SW Shmin, the transtensional fault segments of Biskra and Alima formed the boundaries of the Khanguet Sidi Neji-Gafsa (KSG) Basin, which developed as a Z-shaped dextral releasing stepover. During the Cenozoic, the KSG Basin was inverted, under NW-SE SHmax, in response to the Africa-Eurasia convergence. This inversion occurred mainly along basin sidewalls by reactivation of the pre-existing normal-oblique faults as right-lateral transpressional shears. Further east, the E-W dextral strike-slip faults of Orbata and Bouhedma connected via a NE-SW restraining stepover. Finally, all E-W dextral strike-slip fault segments are associated with ENE right-stepping en echelon folds and Riedel shear patterns of different scales, in response to basement wrenching. Currently, most fault zones are still active with deep strike-slip earthquakes.

中文翻译：

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与撒哈拉-突尼斯南部阿特拉斯（北非）板内走滑断层系统相关的变形方式：新运动学模型

摘要 迄今为止，尚未对北非撒哈拉-突尼斯南部阿特拉斯走滑断层系统的复杂几何形状和构造演化进行全面研究。本文提出了新的概念模型，以更好地理解这些板内断层带的构造样式。我们使用多学科方法，包括现场观测、地质填图、应力分析和地震数据，来研究主要走滑断层段的发展和相互作用。区域断层系统以构成主位移带 (PDZ) 的东西向的 Biskra、Alima、Orbata、Bouhedma 和 Chotts 基底断层为主。我们的分析和解释表明，每个 PDZ 都具有典型的右旋走滑结构，包括通过扩张和收缩跨步/弯曲连接的多尺度断层段。在中生代，在 NE-SW Shmin 之下，Biskra 和 Alima 的横张断层段形成了 Khanguet Sidi Neji-Gafsa (KSG) 盆地的边界，该盆地发展为 Z 形右旋释放阶梯。在新生代，KSG 盆地在 NW-SE SHmax 下倒置，以响应非洲-欧亚大陆的辐合。这种反转主要发生在盆地侧壁上，这是通过将预先存在的正斜断层重新激活为右侧横压切变而发生的。再往东，Orbata 和 Bouhedma 的 EW 右旋走滑断层通过 NE-SW 抑制步距连接。最后，所有 EW 右旋走滑断层段都与 ENE 右阶梯形褶皱和不同尺度的 Riedel 剪切模式有关，以响应基底扭动。目前，大部分断层带仍存在深部走滑地震活动。