Abstract Active shortening structures in Northern Tunisia have developed by tectonic inversion since the Pliocene, after Late Miocene extensional collapse of the whole region. Restored Plio-Quaternary deformation observed on reflection seismic lines indicates deformation rates around 0.6–0.8 mm/yr in the studied segments and larger amounts of shortening to the West of Northern Tunisia (16%) than to the East (7%), which suggests tectonic inversion started earlier to the West and later propagated eastwards, reaching Northeastern Tunisia in the Late Pliocene. This shortening is registered on striated pebbles in Quaternary alluvial terraces and fault-slip data giving two populations of strain ellipsoids with N–S and WNW-ESE maximum shortening. Morphometric analysis in combination with field fault segmentation mapping show that topographic uplift and drainage rejuvenation occurs in relation to 20–30 km long ENE-WSW reverse fault segments and related antiforms that are offset and linked by E-W to WNW-ESE dextral and NE-SW-oriented sinistral faults. The largest fully linked fault system is the Alia-Thibar fault. This 130 km long fault zone shows an helicoidal geometry with five different fault segments, including reverse, dextral, sinistral and oblique faults. Due to the young age of tectonic inversion, after late Miocene extensional collapse of the region, the present relief of Northern Tunisia is characteristic of a young thrust and fold belt, with dominating axial valleys along synforms and an incipient transverse drainage development propagating from West to East.

中文翻译：

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突尼斯北部的活动断层分割

摘要 突尼斯北部自上新世以来，在整个地区晚中新世伸展塌陷后，通过构造反转发展了活动的缩短构造。在反射地震线上观察到的恢复的 Plio-第四纪变形表明，研究段的变形率约为 0.6-0.8 毫米/年，突尼斯北部西部 (16%) 的缩短量大于东部 (7%)，这表明构造反转较早开始向西，后来向东传播，在上新世晚期到达突尼斯东北部。这种缩短记录在第四纪冲积阶地的条纹卵石和断层滑动数据上，给出了两个具有 N-S 和 WNW-ESE 最大缩短的应变椭球群。结合现场断层分段绘图的形态测量分析表明，与 20-30 公里长的 ENE-WSW 反向断层段和相关的反形体相关，地形隆起和排水系统发生了复兴，这些断层被 EW 偏移并连接到 WNW-ESE 右旋和 NE-SW向左断层。最大的全连接断层系统是 Alia-Thibar 断层。这个 130 公里长的断层带显示了一个螺旋几何形状，有五个不同的断层段，包括反向断层、右旋断层、左旋断层和斜断层。由于构造反转时代年轻，在该地区晚中新世拉张塌陷后，突尼斯北部目前的地势具有年轻的逆冲褶皱带的特征，沿同形体的轴向谷地占主导地位，早期的横向排水发育从西向东方的。