The Iglesia basin is a ∼3.5 km thick depocenter that holds an outstanding record of the late Cenozoic tectosedimentary evolution of the southern Central Andes. Previous studies have indicated an initial tectonic stage associated with NNE-striking basin-bounding faults, formed by extension in the Late Oligocene (?)-early Miocene, and a subsequent basin inversion stage in the middle-Late Miocene. We conducted a multi-disciplinary study that allowed us to unravel a conspicuous structural system orthogonal to the previous basin-bounding faults. The analysis of seismic reflection lines, satellite and local gravimetry, and field data allowed the recognition of WNW-striking thrust fault zones involving the basement and Cenozoic sedimentary cover of the Iglesia basin. Also, we document Pliocene growth strata in seismic reflection lines and intra-Pliocene thrust faults at the surface that inform the timing of transverse fault activity. Therefore, we propose new tectonic stage during the Pliocene associated with the onset of a transitory NNE-trending contractional stress field, which triggered the reactivation of inherited basement structures transverse to the main Andean strike. This indicates a transient shifting in the stress field at ∼5 Ma that we associate with a major upper-plate reconfiguration caused by the full development of the Pampean flat-slab and major plate coupling.

伊格莱西亚盆地是一个厚约 3.5 公里的沉积中心，拥有中安第斯山脉南部晚新生代构造沉积演化的杰出记录。先前的研究表明，在晚渐新世（？）-早中新世的伸展形成的 NNE 走向盆地边界断层的初始构造阶段，以及随后在中晚中新世中的盆地反转阶段。我们进行了一项多学科研究，使我们能够解开一个与以前的盆地边界断层正交的显着结构系统。通过对地震反射线、卫星和当地重力测量以及现场数据的分析，我们可以识别出涉及伊格莱西亚盆地基底和新生代沉积盖层的西北西向逆冲断层带。还，我们记录了地震反射线中的上新世生长地层和地表的上新世内逆冲断层，这些断层为横向断层活动的时间提供了信息。因此，我们提出上新世新的构造阶段与过渡的 NNE 趋势收缩应力场的开始有关，这引发了与安第斯主要走向横切的继承基底结构的重新激活。这表明在 5 Ma 时应力场的瞬态变化与由 Pampean 平板和主要板耦合的全面发展引起的主要上板重构相关联。这触发了与安第斯主要走向横切的继承基底结构的重新激活。这表明在 5 Ma 时应力场的瞬态变化与由 Pampean 平板和主要板耦合的全面发展引起的主要上板重构相关联。这触发了与安第斯主要走向横切的继承基底结构的重新激活。这表明在 5 Ma 时应力场的瞬态变化与由 Pampean 平板和主要板耦合的全面发展引起的主要上板重构相关联。