This contribution investigates the role of a hyperextended rift system in the formation of the Basque–Cantabrian Pyrenees by discussing their present-day architecture as well as the inherited rift template. Moreover, this work attempts to decipher the onset of reactivation of a hyperextended system and to discuss the related processes during collision. To carry out this study, two regional, crustal-scale cross-sections are presented that provide geological and geophysical information and interpretations across the Central and Western Basque–Cantabrian Pyrenees. Moreover, the two sections are restored back to the Cenomanian and Barremian, corresponding to the end of two independent rift stages respectively. The two sections document different structural styles observed along the orogenic belt. The Central section, involving the Iberian and European plates, shows a thin-skinned structural style, where the Upper Triassic salt acted as a decoupling level between the sedimentary cover and the underlying basement during both extension and reactivation. The Western section, by contrast, crosses only the Iberian plate (i.e., intra-plate section) and displays a hybrid situation showing both thin- and thick-skinned structural styles that were conditioned by the irregular distribution of Triassic salt. Extensional deformation was localised in the north (i.e., Bay of Biscay) and less important in the south. Despite compressional reactivation, the northern part of the Western section preserves its rift template, which provides key insights to restore the internal part of the Central section. In contrast to the Western section, the Central section shows stacked depocenters, resulting from overprinted Mesozoic rift events that had a first order control on the subsequent reactivation. This study corroborates the importance of rift inheritance during the onset of convergence by reactivating the most distal and weak part of the rift system (i.e., serpentinised mantle) before starting the collision phase. A key learning is that the understanding of the nature and distribution of decoupling levels at a crustal scale is fundamental to reconstruct the structural evolution during the formation and reactivation of a hyperextended rift system.

中文翻译：

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超延伸裂谷系统的重新激活：巴斯克-坎塔布连比利牛斯山脉案例

本贡献通过讨论巴斯克-坎塔布连比利牛斯山脉的现代建筑以及继承的裂谷模板，研究超延伸裂谷系统在形成巴斯克-坎塔布连比利牛斯山脉中的作用。此外，这项工作试图破译超扩展系统重新激活的开始，并讨论碰撞期间的相关过程。为了开展这项研究，我们展示了两个区域地壳尺度横截面，它们提供了巴斯克-坎塔布连比利牛斯山脉中部和西部的地质和地球物理信息和解释。而且，这两个断面恢复回森诺曼阶和巴雷米阶，分别对应两个独立裂谷阶段的结束。这两个部分记录了沿造山带观察到的不同构造样式。中区，涉及伊比利亚和欧洲板块，显示出薄皮结构样式，其中上三叠统盐在伸展和再活化过程中充当沉积盖层和下伏基底之间的脱钩层。相比之下，西部剖面仅穿过伊比利亚板块（即板块内剖面）并显示出混合情况，显示出由三叠纪盐分的不规则分布决定的薄皮和厚皮构造样式。拉伸变形集中在北部（即比斯开湾），南部不太重要。尽管受到挤压重新激活，西段北部仍保留其裂谷模板，这为恢复中段内部提供了关键见解。与西区相比，中央部分显示堆积的沉积中心，由叠加的中生代裂谷事件产生，这些事件对随后的再激活具有一级控制。这项研究通过在碰撞阶段开始之前重新激活裂谷系统最远端和最薄弱的部分（即蛇纹石化地幔），证实了裂谷遗传在收敛开始期间的重要性。一个关键的学习是，了解地壳尺度上解耦水平的性质和分布对于重建超伸展裂谷系统形成和重新激活过程中的结构演化至关重要。这项研究通过在碰撞阶段开始之前重新激活裂谷系统最远端和最薄弱的部分（即蛇纹石化地幔），证实了裂谷遗传在收敛开始期间的重要性。一个关键的学习是，了解地壳尺度上解耦水平的性质和分布对于重建超伸展裂谷系统形成和重新激活过程中的结构演化至关重要。这项研究通过在碰撞阶段开始之前重新激活裂谷系统最远端和最薄弱的部分（即蛇纹石化地幔），证实了裂谷遗传在收敛开始期间的重要性。一个关键的学习是，了解地壳尺度上解耦水平的性质和分布对于重建超伸展裂谷系统形成和重新激活过程中的结构演化至关重要。