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34 pages, 11 figures [EN] A long-standing challenge in tectonics is to evaluate the role of inheritance and define the initial conditions of a geodynamic system, which are prerequisites to understand and model its evolution with some accuracy. Here we revisit the concept of “inheritance” by distinguishing “interface shape inheritance”, which includes the transient thermal state and gravitational potential energy, and “persisting inheritance”, which encompasses long-lasting structural and compositional inheritance. This new approach allows us to investigate, at each stage of a Wilson Cycle, the interplay between inheritance (innate/“genetic code”) and the physical processes at play (extension/compression, magmatism etc.). The aim of this paper is to provide a conceptual framework that integrates the role of inheritance in the study of rifts, rifted margins and collisional orogens based on the work done in the OROGEN project, which focuses on the Biscay-Pyrenean system. The Biscay-Pyrenean rift system resulted from a multistage rift evolution that developed over a complex lithosphere pre-structured by the Variscan orogenic cycle. There is a general agreement that the Pyrenean-Cantabrian orogen resulted from the reactivation of an increasingly mature rift system along-strike, ranging from mature rifted margins in the west to an immature and segmented hyperextended rift in the east. However, different models have been proposed to explain the preceding rifting and its influence on the subsequent reactivation. Results from the OROGEN project highlight the sequential reactivation of rift-inherited decoupling horizons and identify the specific role of exhumed mantle, hyperextended and necking domains during compressional reactivation. They also highlight the contrasting fate of rift segment centres versus segment boundaries during convergence, explaining the non-cylindricity of internal parts of collisional orogens. Results from the OROGEN project also suggest that the role of inheritance is more important during the initial stages of collision, which may explain the higher complexity of internal parts of orogenic systems with respect to their external parts. In contrast, when the system involved in the orogeny is more mature, the orogenic evolution is mostly controlled by first-order physical processes as described in the Coulomb Wedge theory, for instance. This may account for the simpler and more continuous architecture of external parts of collisional orogens and may also explain why most numerical models can reproduce mature orogenic architectures with a better accuracy compared to those of initial collisional stages. The new concepts developed from the OROGEN research are now ready to be tested at other orogenic systems that result from the reactivation of rifted margins, such as the Alps, the Colombian cordilleras and the Caribbean, Taiwan, Oman, Zagros or Timor [FR] Un défi de longue date en tectonique consiste à évaluer le rôle de l’héritage et à définir les conditions initiales d’un système géodynamique. Ceux-ci sont en effet des prérequis pour comprendre et modéliser l’évolution d’un tel système avec une certaine précision. Nous revisitons ici le concept d’« héritage » en distinguant « l’héritage (transitoire) d’interfaces », qui comprend d’un côté l’état thermique et de l’autre l’énergie potentielle gravitationnelle, et « l’héritage persistant » qui englobe les hétérogénéités structurales et compositionnelles. Cette nouvelle approche permet d’étudier, à chaque étape du Cycle de Wilson, l’interaction entre l’héritage (inné/« code génétique » du système) et les processus physiques en jeu (extension/compression, magmatisme, etc.). Le but de cet article est de fournir un cadre conceptuel qui intègre le rôle de l’héritage dans l’étude des rifts, des marges riftées et des orogènes de collision, à partir des travaux réalisés dans le projet OROGEN dans le système Gascogne-Pyrénées. Le système de rift Gascogne-Pyrénées résulte de plusieurs épisodes extensifs qui ont successivement affecté une lithosphère déjà complexe car pré-structurée par le cycle orogénique Varisque. Il est généralement accepté que l’orogénèse pyrénéo-cantabrique a résulté de la réactivation d’un système de rift dont la maturité varie d’est en ouest, allant de marges conjuguées matures à l’ouest à un rift hyper-étiré, immature et segmenté à l’est. Cependant, différents modèles ont été proposés pour expliquer l’évolution précédant le rifting et son influence sur la réactivation ultérieure. Les résultats du projet OROGEN montrent une réactivation séquentielle des horizons de découplage hérités du rift et identifient le rôle spécifique des domaines de manteau exhumé, d’hyperextension et d’étranglement lors de la réactivation. Ils mettent également en évidence le sort contrasté des centres de segments de rifts par rapport à leurs bordures lors de l’inversion, expliquant la non-cylindricité des parties internes des orogènes de collision. Les résultats du projet OROGEN suggèrent également que le rôle de l’héritage est plus important pendant les étapes initiales de subduction et de collision, ce qui peut expliquer la plus grande complexité des parties internes des systèmes orogéniques par rapport à leurs parties externes. En revanche, quand les systèmes de rift impliqués sont plus matures, l’évolution orogénique est principalement contrôlée par des processus physiques de premier ordre, tels que ceux décrits par la théorie du Prisme de Coulomb. Ce constat pourrait expliquer l’architecture plus simple et plus continue des parties externes des orogènes de collision par rapport à leurs parties internes, et pourrait également expliquer pourquoi la plupart des modèles numériques reproduisent mieux les architectures orogéniques matures que celles des stades initiaux de collision Les nouveaux concepts développés à partir de la recherche menée lors du projet OROGEN sont désormais prêts à être testés sur d’autres systèmes orogéniques résultant de la réactivation de marges riftées, comme les Alpes, la Cordillère colombienne, les Caraïbes, Taiwan, Oman, Zagros ou encore le Timor This study was funded by the Orogen project, a tripartite joint academic-industry research program between the CNRS, BRGM, and Total R&D Frontier Exploration program With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)

The Pyrenean-Cantabrian Orogen arose through the collision of the Iberian and Eurasian plates, mostly in Cenozoic times. This orogen comprises two main mountain ranges, the Pyrenees to the east, and the Cantabrian Mountains to the west. To date, the early Alpine tectono-sedimentary phases preserved in the Cantabrian Mountains, of Permian and Triassic age, have been considered independently from the same phases in neighbouring basins of SW Europe, and even from the eastern part of the same orogeny (the Pyrenean orogeny). In consequence, the beginning of the Alpine cycle in the Cantabrian Mountains has been interpreted within a specific geodynamic context, far from the general evolutionary phases of the western Peri-Tethys basins. Through detailed field work, including geological mapping, sedimentology, lithostratigraphy and petrology of volcanic rocks, and new palaeontological data, here we define several new lithostratigraphical formations and five new tectono-sedimentary cycles (TS I-V) for the initial phases of evolution of the Mesozoic Basque-Cantabrian Basin, interrupted by periods of tectonic stability. To complete this information, we include data from an onshore borehole (Villabona Mine) and two offshore boreholes constrained by 2D reflection seismic profiles acquired in the North Iberian continental platform. The main tectono-sedimentary cycles, related to the deposition of five major identified lithostratigraphic units, can be described as follows: TS I (late Gzelian-early Asselian), relating to the late Variscan deformation and preserved in a single outcrop in all the Cantabrian Mountains (San Tirso Formation). This formation is constituted by medium-distal alluvial fan deposits in which humid intervals predominate, forming some thin coal beds. TS II (Asselian-Sakmarian), a post-Variscan extensional phase with associated calc-alkaline magmatism, represented by profuse volcanic and volcanosedimentary intercalations in the early Permian sedimentary basins (Acebal Formation) and small plutons in surrounding areas. TS III (Kungurian), or reactivation of the post-Variscan extension leading to alluvial and lacustrine carbonate sedimentation in arid climate conditions, which do not change during the rest of the Permian and Triassic periods (Sotres Formation). A generalized karstification in the basin represents the end of Permian deposition, followed by an interruption in sedimentation longer than 30 Myr. The Permian tectono-sedimentary cycles (TS II and TS III) are contemporary with Variscan belt collapse and the basins are controlled by extensional reactivation of NE-SW and E-W Variscan structures, and NW-SE late Variscan structures. TS IV (late Anisian–middle Carnian), renewed sedimentation in more extensive basins, precursors of the great Mesozoic Basque-Cantabrian Basin. This cycle is represented by fluvial deposits (Cicera Formation, or Buntsandstein facies), which are interrupted by the first Mesozoic marine ingression (Rueda Formation, or Muschelkalk facies). TS V (Norian-Rhaetian), or shallow marine carbonate deposits (Transición Formation) related to increasingly compartmentalized sub-basins, controlled by normal faults. This final TS is broadly connected with different basins of the western Peri-Tethys domain. The identification of units TS I-V in the Cantabrian Mountains along with the volcanic character of TS II, all indicate the development of a common post-Variscan to early Alpine tectono-sedimentary evolution for the whole Pyrenean-Cantabrian realm. This work was funded by projects CGL2014-52699P and CGL2015-70970-P (Spanish Ministry of Economy and Competitiveness and FEDER Funds of the European Union), as well as projects: >Sistemas Sedimentarios y Variabilidad Climática> (642853) of the CSIC, Basin Analysis (910429), and Palaeoclimatology and Global Change (910198) of the Universidad Complutense de Madrid. The authors thank Luis Villa Iglesias and José Antonio Marín Barcaíztegui (MINERSA GROUP) for providing all the required borehole data from the Villabona Mine (Asturias) and for facilitating access to the mines for sampling. We thank both anonymous referees and Editor Andre Strasser for improving the final version with their comments, and A. Burton for reviewing the English.

The Cantabrian Fault is a long-lived crustal fault, 320 km long on land and extending more than 150 km seawards within the Bay of Biscay, which separates different geodynamic domains. Due to its sub-vertical dip and late strike slip movement is poorly evidenced in the shelf and it has been traditionally mapped following the strike of the deepest submarine canyon in the north Atlantic (~4.600 m drop). Based on multichannel reflection data, seismicity from a thirty year period, a GIS model, and the support of detailed field mapping onshore, the fault has been traced more accurately. Surprisingly, it presents a much more E-W strike than mapped before, and shows a splay fault termination never previously assessed. Moreover, the fault acts as a seismic barrier within the actual stress field of Iberia. Collaterally, a large submarine landslide (2000 km(2)) associated with its seismicity has been discovered, providing a further argument to support the newly proposed trace of the fault.