Nicolas Saspiturry
email: saspiturry.nicolas@gmail.com

Philippe Razin

Thierry Baudin

Riccardo Asti

Yves Lagabrielle

Cécile Allanic

Olivier Serrano

Thibault Duretz

Review of Iberia-Eurasia plate-boundary basins: Role of sedimentary burial and salt tectonics during rifting and continental breakup

Keywords: Iberian-European boundary, Sedimentary burial, Salt tectonics, Depth-dependent thinning, Ductile regime, HT/LP metamorphism

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Introduction

Recent models and concepts related to hyperextended continental margins have been defined on North Atlantic passive margins such as West Iberia/Newfoundland [START_REF] Boillot | Ocean-continent boundary of the Iberian margin: a serpentinite diapir west of the Galicia Bank[END_REF][START_REF] Boillot | The formation of passive margins: constraints from the crustal structure and segmentation of the deep Galicia margin, Spain[END_REF][START_REF] Reston | Detachment tectonics during Atlantic rifting: analysis and interpretation of the S reflection, the west Galicia margin[END_REF][START_REF] Whitmarsh | Evolution of magma-poor continental margins from rifting to seafloor spreading[END_REF]Péron-Pinvidic & Manatschal, 2009;[START_REF] Péron-Pinvidic | Unravelling the along-strike variability of the Angola-Gabon rifted margin: a mapping approach[END_REF], Norway/Greenland [START_REF] Osmundsen | Deep structure of the Mid Norway rifted margin[END_REF][START_REF] Osmundsen | Styles of extension offshore mid-Norway and implications for mechanisms of crustal thinning at passive margins: STYLES OF EXTENSION OFFSHORE NORWAY[END_REF][START_REF] Osmundsen | Crustal-Scale Fault Interaction at Rifted Margins and the Formation of Domain-Bounding Breakaway Complexes: Insights From Offshore Norway[END_REF], and the Alps [START_REF] Lemoine | Ultramafic and gabbroic ocean floor of the Ligurian Tethys (Alps, Corsica, Apennines): In search of a genetic imodel[END_REF][START_REF] Froitzheim | Kinematics of Jurassic rifting, mantle exhumation, and passive-margin formation in the Austroalpine and Penninic nappes (eastern Switzerland)[END_REF][START_REF] Manatschal | A continent-ocean transition recorded in the Err and Platta nappes (Eastern Switzerland)[END_REF][START_REF] Manatschal | What is the tectono-metamorphic evolution of continental breakup: The example of the Tasna Ocean-Continent Transition[END_REF][START_REF] Masini | The tectonosedimentary evolution of a supra-detachment rift basin at a deep-water magma-poor rifted margin: the example of the Samedan Basin preserved in the Err nappe in SE Switzerland: Tectono-sedimentary evolution of a supra-detachment rift basin[END_REF]Mohn et al., 2014). They describe the mechanisms responsible for continental crust thinning and subcontinental mantle exhumation at the ocean-continent transition, and have shown that the hyperextended domain of continental margins is characterized by (1) sediment starved conditions with very thin pre-rift and syn-rift sedimentary sequences, (2) asymmetric margins, and [START_REF] Tugend | Formation and deformation of hyperextended rift systems: Insights from rift domain mapping in the Bay of Biscay-Pyrenees[END_REF] coupled deformation between the basement and sedimentary cover resulting in the formation of extensional allochthons. The syn-rift and post-rift units have been respectively defined as strata deposited during (1) the last extension episode leading to continental breakup and (2) a period of relative tectonic quiescence above a regional breakup unconformity [START_REF] Driscoll | Extensional tectonics in the Jeanne d'Arc asin, offshore Newfoundland: implications for the timing of breakup between Grand Banks and Iberia[END_REF][START_REF] Wilson | Rifting along non-volcanic passive margins: Stratigraphic and seismic evidence from the Mesozoic successions of the Alps and western Iberia, in Nonvolcanic Continental Margins: A Comparison of Evidence From Land and Sea[END_REF]. DSDP and ODP drilling expeditions along the West-Iberia margin have also contributed to a more complete understanding of how continental breakup is recorded in syn-rift to post-rift sedimentary sequences (Alves & Cunha, 2018), and how it evolves through time along the strike of continental margins [START_REF] Alves | Diachronous evolution of Late Jurassic-Cretaceous continental rifting in the northeast Atlantic (west Iberian margin)[END_REF]. Indeed, such data allowed the identification of syn-rift, breakup and post-rift sequences as correlating with major phases of crustal thinning, mantle denudation and oceanic spreading [START_REF] Alves | Diachronous evolution of Late Jurassic-Cretaceous continental rifting in the northeast Atlantic (west Iberian margin)[END_REF][START_REF] Soares | The breakup sequence and associated lithospheric breakup surface: their significance in the context of rifted continental margins (West Iberia and Newfoundland margins, North Atlantic)[END_REF][START_REF] Soares | Sedimentological and stratigraphical aspects of the syn-to post-rift transition on fully separated conjugate margins[END_REF]Alves & Cunha, 2018;[START_REF] Alves | A tectonostratigraphic review of continental breakup on intraplate continental margins and its impact on resultant hydrocarbon systems[END_REF]. Continental breakup is thus defined as the deposits that are correlated with the phases of hyperextension and mantle denudation on magma-poor continental margins [START_REF] Soares | The breakup sequence and associated lithospheric breakup surface: their significance in the context of rifted continental margins (West Iberia and Newfoundland margins, North Atlantic)[END_REF]. [START_REF] Alves | A tectonostratigraphic review of continental breakup on intraplate continental margins and its impact on resultant hydrocarbon systems[END_REF] have demonstrated that continental breakup is only possible along magma-poor Type I margins (sensu [START_REF] Huismans | Symmetric and asymmetric lithospheric extension: Relative effects of frictional-plastic and viscous strain softening[END_REF], 2008, 2011, 2014). Indeed, the upper lithosphere in Type I margins is much more coupled to the continental crust than in Type II margins [START_REF] Alves | A tectonostratigraphic review of continental breakup on intraplate continental margins and its impact on resultant hydrocarbon systems[END_REF]. Thus, along Type II margins, the upper lithosphere is laterally subtracted and mantle denudation cannot occur. Syn-rift and breakup sequences are delimited by major unconformities corresponding (from bottom to top) to the base syn-rift unconformity (BSU; base of syn-rift sequence), the lithospheric breakup surface (LBS; base of the breakup sequence) and the base post-rift unconformity (BPU; base of the post-rift sequence) as defined by [START_REF] Soares | The breakup sequence and associated lithospheric breakup surface: their significance in the context of rifted continental margins (West Iberia and Newfoundland margins, North Atlantic)[END_REF] and [START_REF] Soares | Sedimentological and stratigraphical aspects of the syn-to post-rift transition on fully separated conjugate margins[END_REF]. While Atlantic-type margins develop under conditions of high mantle heat flow, as the product of asthenosphere upwelling and subsequent denudation of subcontinental mantle (e.g., [START_REF] Huismans | Symmetric and asymmetric lithospheric extension: Relative effects of frictional-plastic and viscous strain softening[END_REF], 2008, 2011, 2014;[START_REF] Lavier | A mechanism to thin the continental lithosphere at magma-poor margins[END_REF][START_REF] Brune | Rift migration explains continental margin asymmetry and crustal hyper-extension[END_REF][START_REF] Brune | Abrupt plate accelerations shape rifted continental margins[END_REF], the North Pyrenean hyperextended rift system differs from the Atlantic type by the presence of hightemperature/low-pressure (HT/LP) metamorphism (Albarède & Michard-Vitrac, 1978a, 1978b;[START_REF] Golberg | Petrological and age relationship between emplacement of magmatic breccia, alkaline magmatism, and static metamorphism in the North Pyrenean Zone[END_REF][START_REF] Montigny | K-Ar Study of cretaceous magmatism and metamorphism in the Pyrenees: Age and length of rotation of the Iberian Peninsula[END_REF]Golberg & Maluski, 1988;[START_REF] Golberg | High temperature-low pressure Cretaceous metamorphism related to crustal thinning (Eastern North Pyrenean Zone, France)[END_REF][START_REF] Thiébaut | Métamorphisme des évaporites triasiques du versant nord des Pyrénées centrales et Occidentales[END_REF]. The North Pyrenean rift basins were affected by a syn-rift stage throughout the Early Cretaceous that evolved to continental breakup and mantle denudation during the Latest Albian to Early Cenomanian [START_REF] Debroas | Les brèches d'Urdach, témoins de l'exhumation du manteau pyrénéen dans un escarpement de faille vraconniencénomanien inférieur (Zone nord-pyrénéenne, Pyrénées-Atlantiques, France)[END_REF]Saspiturry et al., 2019a;[START_REF] Espurt | Crustal-scale balanced cross-section and restorations of the Central Pyrenean belt (Nestes-Cinca transect): Highlighting the structural control of Variscan belt and Permian-Mesozoic rift systems on mountain building[END_REF][START_REF] Labaume | Evolution of salt structures of the Pyrenean rift (Chaînons Béarnais, France): From hyper-extension to tectonic inversion[END_REF]. Thus, these margins can be defined as Type I margins as mantle denudation occured during continental breakup (sensu [START_REF] Huismans | Symmetric and asymmetric lithospheric extension: Relative effects of frictional-plastic and viscous strain softening[END_REF], 2008, 2011, 2014). The hyperextended domain of these basins is interpreted to have stretched under high-temperature conditions under a predominantly ductile regime, resulting in the generation of large-scale boudins whose formation was controlled by a strong thermal and structural inheritance [START_REF] Clerc | [END_REF][START_REF] Clerc | High-temperature metamorphism during extreme thinning of the continental crust: a reappraisal of the North Pyrenean passive paleomargin[END_REF]Clerc et al., , 2015b;;[START_REF] Corre | Deformation associated with mantle exhumation in a distal, hot passive margin environment: New constraints from the Saraillé Massif (Chaînons Béarnais, North-Pyrenean Zone)[END_REF][START_REF] De | Northwest-Iberia margin[END_REF][START_REF] Teixell | The crustal evolution of the west-central Pyrenees revisited: Inferences from a new kinematic scenario[END_REF]Lagabrielle et al., 2016[START_REF] Lagabrielle | [END_REF][START_REF] Asti | How Do Continents Deform During Mantle Exhumation? Insights From the Northern Iberia Inverted Paleopassive Margin, Western Pyrenees (France)[END_REF]. The major difference between the hyperextended Atlantictype and Pyrenean Cretaceous rift margins is the rare occurrence of tilted crustal blocks and related stepping fault scarps in the central parts of the basins, thus defining a dominantly symmetrical basement profile with smooth slopes (see [START_REF] Lagabrielle | A review of cretaceous smooth-slopes extensional basins along the Iberia-Eurasia plate boundary: How pre-rift salt controls the modes of continental rifting and mantle exhumation[END_REF] for a review).

Several other rift basins apart from the North Pyrenean rift basins exist along the plate boundary separating Iberia from the Eurasia plate and share several features in common with the Pyrenean system. They include the Tartas, Arzacq, Columbrets, Cameros and Parentis syn-rift basins, which developed during Late Jurassic to Early Cretaceous rifting (more details in the review section). The development of these basins is time-equivalent to the Late Jurassic-Aptian rifting and Albian-Cenomanian breakup sequence of the V-shaped Bay of Biscay margin [START_REF] Montadert | Northeast Atlantic passive continental margins: Rifting and subsidence processes[END_REF][START_REF] Barbier | Structure profonde de la marge Nord Gascogne. Implications sur le mécanisme de rifting et de formation de la marge continentale[END_REF][START_REF] Thinon | Structure profonde de la marge Nord Gascogne et du Bassin armoricain[END_REF][START_REF] Vergés | Mesozoic evolution and Cenozoic inversion of the Pyrenean rift[END_REF][START_REF] Thinon | Deep structure of the Armorican Basin (Bay of Biscay): a review of Norgasis seismic reflection and refraction data[END_REF][START_REF] Tugend | Formation and deformation of hyperextended rift systems: Insights from rift domain mapping in the Bay of Biscay-Pyrenees[END_REF] and the NW-Iberia margin [START_REF] Soares | The breakup sequence and associated lithospheric breakup surface: their significance in the context of rifted continental margins (West Iberia and Newfoundland margins, North Atlantic)[END_REF]Alves & Cunha, 2018;[START_REF] Alves | A tectonostratigraphic review of continental breakup on intraplate continental margins and its impact on resultant hydrocarbon systems[END_REF]. All of these basins share similarities that include (1) a small amount of brittle deformation affecting the upper crust, (2) a pre-rift cover that is efficiently decoupled from its substratum thanks to the thick layer of Late Triassic to earliest Jurassic evaporites, (3) hyperthinned continental crust resulting from a polyphase rifting history, (4) a thick pre-rift to syn-rift sedimentary pile and (5) HT/LP syn-rift metamorphism. This paper presents a structural and sedimentological review of these smoothslope type basins that sheds light on the major role of sedimentary burial and decoupling levels in controlling the ductile crustal thinning of the Iberia-Eurasia plate boundary basins during the syn-rift and breakup stages. We also compare the processes responsible for continental crust thinning and discuss the timing of formation of the smooth-slope type basins with respect to the evolution of the West Iberia and Bay of Biscay hyperextended continental margins.

Mesozoic basins of Iberia and Europe

Aquitaine basin and the Tartas and Arzacq basins

The Aquitaine basin started to develop during the Late Permian in an extensional context related to the breakup of Pangea [START_REF] Burg | Syn-to post-thickening extension : mode and consequences[END_REF]. During the Triassic and earliest Jurassic (Hettangian), extension led to an aborted rift basin filled with clastic rocks, carbonates, and an evaporite sequence ~1-2 km thick [START_REF] Curnelle | The Mesozoic-Tertiary Evolution of the Aquitaine Basin [and Discussion[END_REF][START_REF] Curnelle | Evolution structuro-sédimentaire du Trias et de l'Infra-Lias d'Aquitaine[END_REF][START_REF] Curnelle | Evolution mesozoique des grands bassins sedimentaires francais; bassins de Paris, d'Aquitaine et du Sud-Est[END_REF]. The Jurassic was a tectonically stable period marked by the development of a widespread carbonate platform [START_REF] Peybernès | Le Jurassique et le Crétace inferieur des Pyrénées franco-espagnoles entre la Garonne et la Méditérranée[END_REF]. At the end of the Jurassic, the entire platform was confined as suggested by the deposition of restricted dolomite and anhydrite facies (BRGM et al., 1974;[START_REF] Serrano | Le bassin d'Aquitaine: valorisation des données sismiques, cartographie structurale et potentiel pétrolier[END_REF]. The Jurassic pre-rift carbonate platform was uplifted, weathered and partly eroded [START_REF] Combes | Altérites et bauxites, témoins des marges européenne et ibérique des Pyrénées occidentales au Jurassique supérieur-Crétacé inférieur, à l'ouest de la vallée d'Ossau (Pyrénées-Atlantiques, France)[END_REF][START_REF] James | La plate-forme carbonatée ouest-pyrénéenne au jurassique moyen et supérieur stratigraphie séquentielle, stades d'évolution, relations avec la subsurface en aquitaine méridionale[END_REF][START_REF] Canérot | Le cadre stratigraphique et géodynamique des altérites et des bauxites sur la marge ibérique des Pyrénées occidentales (France)[END_REF] in response to asthenosphere upwelling that preceded Early Cretaceous rifting (Saspiturry et al., 2019a). The Early Cretaceous was a structurally active time in which the Aquitaine basin evolved into different syn-rift basins characterised by very rapid subsidence (up to 130 m/Myr; [START_REF] Désaglaux | Tectonic subsidence of the Aquitaine basin since Cretaceous times[END_REF][START_REF] Brunet | Subsidence et géodynamique du assin d'Aquitaine[END_REF], including the symmetric Arzacq and Tartas basins. A ~1-3 km thick Early Cretaceous syn-rift sedimentary sequence unconformably overlies pre-rift deposits of Triassic and Jurassic age totalling 2-3 km in thickness [START_REF] Serrano | Le bassin d'Aquitaine: valorisation des données sismiques, cartographie structurale et potentiel pétrolier[END_REF].

Tartas basin

The Tartas basin is located in the southern part of the Aquitaine domain (Fig. 1). It is bounded to the north by the Celtaquitaine Flexure (BRGM et al., 1974), which separates the Tartas Basin and the North Aquitaine Platform, and to the south by the Audignon-Pécorade-Antin Maubourguet ridge. The Tartas basin is a relatively narrow (20 km) east-west elongated trough [START_REF] Serrano | Le bassin d'Aquitaine: valorisation des données sismiques, cartographie structurale et potentiel pétrolier[END_REF] that lies on slightly thinned continental crust (20-25 km;[START_REF] Wang | The deep roots of the western Pyrenees revealed by full waveform inversion of teleseismic P waves[END_REF]. It formed symmetrically during the Berriasian with the development of widespread shallow-water facies and continued this pattern throughout Early Cretaceous continental rifting. Sediments from this period range from marginal littoral facies (Berriasian to Barremian; e.g., Issautier et al., 2018) to inner-platform facies (Aptian and Albian; e.g., [START_REF] Delfaud | Essai sur la géologie dynamique du domaine aquitano-pyrénéen durant le Jurassique et le Crétacé inférieur[END_REF][START_REF] Arnaud-Vanneau | Paléogéographie des calcaires urgoniens du sud de la France[END_REF][START_REF] Bouroullec | Organisations sédimentaire et paléocologique de l'Aptien supérieur a faciès urgonien dans les Pyrénées occidentales et l'Aquitaine méridionale[END_REF][START_REF] Peybernès | L'Urgonien des Pyrénées, Essai de synthèse[END_REF][START_REF] Peybernès | Création puis évolution de la marge nord-ibérique des Pyrénées au Crétacé inférieur[END_REF].

Throughout the Early Cretaceous rifting, the balance between carbonate production and basin subsidence in the Tartas basin led to the aggradation of a shallow-marine carbonate succession 2500 m thick. The resulting palaeogeography was a homogeneous, flat-floored basin with no major brittle deformation recorded within the basin. High subsidence rates are consistent with ductile pure shear thinning of the lower/middle crust and formation of a symmetric syn-rift basin [START_REF] Issautier | Structural inheritance and salt tectonics controlling pseudosymmetric rift formation during Early Cretaceous hyperextension of the Arzacq and Tartas Basins (southwest France)[END_REF]. This regime was probably enhanced by the presence of a thick evaporite layer of Rhaetian-Hettangian age that favoured mechanical decoupling between the pre-rift sediments and the basement. This salt blanket may account for the lack of illustrated brittle structures in the syn-rift succession of the Tartas basin [START_REF] Issautier | Structural inheritance and salt tectonics controlling pseudosymmetric rift formation during Early Cretaceous hyperextension of the Arzacq and Tartas Basins (southwest France)[END_REF].

Arzacq basin

The Arzacq syn-rift basin lies to the south of the Tartas basin (Fig. 1). Similarly to the Tartas basin, it is 40 km wide, elongated in the N110° direction and overlies slightly thinned continental crust nearly 25 km thick [START_REF] Wang | The deep roots of the western Pyrenees revealed by full waveform inversion of teleseismic P waves[END_REF]. The Arzacq basin is bounded to the north by the Audignon-Pécorade-Antin Maubourguet ridge (Mauriaud, 1987;Mediavilla, 1987;[START_REF] Serrano | Le bassin d'Aquitaine: valorisation des données sismiques, cartographie structurale et potentiel pétrolier[END_REF] and to the south by the North Pyrenean Frontal Thrust [START_REF] Choukroune | The ECORS Pyrenean deep seismic profile reflection data and the overall structure of an orogenic belt[END_REF][START_REF] Daignières | The Arzacq-western Pyrenees ECORS deep seismic profile[END_REF][START_REF] Bourrouilh | The North Pyrenean Aquitaine Basin, France: Evolution and Hydrocarbons[END_REF]. Its southern flank coincides with north-dipping normal faults on the south side of the Grand Rieu ridge (Fig. 2) (e.g., [START_REF] Serrano | Le bassin d'Aquitaine: valorisation des données sismiques, cartographie structurale et potentiel pétrolier[END_REF][START_REF] Masini | The tectonosedimentary evolution of a hyper-extended rift basin: the example of the Arzacq-Mauléon rift system (Western Pyrenees, SW France)[END_REF][START_REF] Gómez-Romeu | Role of rift structural inheritance in orogeny highlighted by the Western Pyrenees case-study[END_REF]Saspiturry et al., 2019a). Early Mesozoic rifting (Triassic to Hettangian) was responsible for a high subsidence rate and the deposition of a thick anhydrite sequence [START_REF] Curnelle | Evolution structuro-sédimentaire du Trias et de l'Infra-Lias d'Aquitaine[END_REF]. The basin's subsequent rifting history was characterised by two successive extensional regimes, the first one symmetric (Berriasian to Aptian) and the second one slightly asymmetric (Albian) [START_REF] Issautier | Structural inheritance and salt tectonics controlling pseudosymmetric rift formation during Early Cretaceous hyperextension of the Arzacq and Tartas Basins (southwest France)[END_REF]. The symmetric syn-rift stage, identical to that of the Tartas basin, was accommodated by ductile flow of the lower/middle continental crust. Again, no brittle structures are recorded, probably because deformation was decoupled by the thick salt blanket [START_REF] Canérot | Mesozoic diapirism in the Pyrenean orogen: Salt tectonics on a transform plate boundary[END_REF][START_REF] Duretz | Numerical modelling of Cretaceous Pyrenean Rifting: The interaction between mantle exhumation and syn-rift salt tectonics[END_REF]. From Berriasian to Barremian times, the palaeogeography was dominated by a shallow marginal carbonate platform (e.g., [START_REF] Bouroullec | Interprétation sédimentologique et paléogéographique par microfaciès du Crétacé inférieur basal d'Aquitaine Sud-Ouest[END_REF][START_REF] Peybernès | Stratigraphie séquentielle du Crétacé basal (intervalle Berriasien-Hauterivien) des Pyrénées centrales et orientales franco-espagnoles[END_REF][START_REF] Biteau | The Aquitaine Basin[END_REF][START_REF] Biteau | La Chaine des Pyrenees et ses avant-pays d'Aquitaine et de l'Ebre: caracteristiques structurales, evolution geodynamique et tectono-sedimentaire[END_REF].

In late Aptian times, the basin differentiated with the growth of a median marl flanked by carbonate-reef and inner-platform deposits [START_REF] Delfaud | Evolution des milieux de dépôts au passage Jurassique-Crétacé du forage de Lacq 104 (Aquitaine, France, Sud-Ouest)[END_REF][START_REF] Delfaud | Evolution des bassins pendant le Crétacé inférieur dans les Pyrénees occidentales et la bordure de l'Aquitaine[END_REF]. This second stage began during the Albian with a sudden change in both palaeogeography and basin geometry, when the depositional profile became asymmetric and salt tectonics affected its flanking ridges (Fig. 2; [START_REF] Issautier | Structural inheritance and salt tectonics controlling pseudosymmetric rift formation during Early Cretaceous hyperextension of the Arzacq and Tartas Basins (southwest France)[END_REF]. Halokinesis consisted of gliding displacement of the Grand Rieu sedimentary cover on the southern side of the basin (Fig. 2), leading to the development of salt-detached ramp synclines as defined by [START_REF] Jackson | Stratigraphic record of translation down ramps in a passive-margin salt detachment[END_REF] and [START_REF] Pichel | Geometry and kinematics of salt-detached ramp syncline basins[END_REF]. Salt diapirism in the Audignon district in the northern side of the basin accompanied this stage (Mauriaud, 1987;Mediavilla, 1987;[START_REF] Issautier | Structural inheritance and salt tectonics controlling pseudosymmetric rift formation during Early Cretaceous hyperextension of the Arzacq and Tartas Basins (southwest France)[END_REF]. As the syn-rift stage continued, the gliding of the sedimentary cover occurred. Motion resulted from simple shear strain localisation along an Albian detachment fault that followed ductile pure shear thinning of the lower/middle crust during the Barremian-Aptian interval [START_REF] Issautier | Structural inheritance and salt tectonics controlling pseudosymmetric rift formation during Early Cretaceous hyperextension of the Arzacq and Tartas Basins (southwest France)[END_REF]. The subsidence history of the Arzacq syn-rift basin also shows that the second stage coincided with an unusually steep geothermal gradient that ended around the initiation of the Pyrenean compression [START_REF] Angrand | Lateral Variations in Foreland Flexure of a Rifted Continental Margin: The Aquitaine Basin (SW France): Flexure of the Aquitaine Foreland Basin[END_REF]. The post-rift stage was marked by the deposition of Cenomanian shallow-water carbonates resting unconformably on Albian strata. Although this basin underwent simple shear thinning during the Albian, it did not reach the stage of continental breakup.

Cameros basin

The Cameros basin, on the northwestern edge of the Iberian mountain chain (Fig. 1), is a WNW-ESE trending synclinorium 80 km wide and 120 km long resulting mostly from Early Cretaceous rifting [START_REF] Guimerà | Inversion of an extensional-ramp basin by a newly formed thrust: the Cameros basin (N. Spain)[END_REF] (Fig. 3). The basin infill has been thrusted onto neighbouring Cenozoic basins, the Ebro basin to the north and the Duero basin to the south (Fig. 3E). It underwent separate rifting stages from Permian to Triassic [START_REF] Alvaro | Un modelo de evolución geotectónica para la Cadena Celtibérica[END_REF] and Late Jurassic to Early Cretaceous times [START_REF] Platt | Basin evolution and fault reactivation in the western Cameros Basin, Northern Spain[END_REF][START_REF] Mas | Evolución tectonosedimentaria de una cuenca extensional intraplaca: la cuenca finijurásica-eocretácica de Los Cameros (La Rioja-Soria)[END_REF]Casas-Sainz & Gil-Imaz, 1998;[START_REF] Salas | Evolution of the Mesozoic central Iberian Rift System and its Cainozoic inversion (Iberian chain)[END_REF]. The Late Jurassic to Early Cretaceous rifting stage was followed by Late Albian thermal subsidence recording the post-rift stage (Omodeo Salè et al., 2014;[START_REF] Omodeo-Salé | Tectono-stratigraphic evolution of an inverted extensional basin: the Cameros Basin (north of Spain)[END_REF], 2017). The associated Late Jurassic to Early Cretaceous synrift sequence ranges from 6.5 to 8 km in thickness (Fig. 3) (Casas-Sainz & Gil-Imaz, 1998;[START_REF] Mas | Evolution of an intra-plate rift basin: the latest Jurassic-early Cretaceous Cameros basin (Northwest Iberian ranges, North Spain)[END_REF][START_REF] Omodeo-Salé | Tectono-stratigraphic evolution of an inverted extensional basin: the Cameros Basin (north of Spain)[END_REF][START_REF] García-Lasanta | Remagnetizations used to unravel large-scale fold kinematics: A case study in the Cameros Basin (Northern Spain): Unfolding in Basin Inversion[END_REF].

The base of the Mesozoic sedimentary pile of the Cameros basin is a 500 m thick Late Triassic salt sequence (Fig. 3) [START_REF] Casas Sainz | Oblique tectonic inversion and basement thrusting in the Cameros Massif (Northern Spain)[END_REF]Casas-Sainz & Gil-Imaz, 1998). A pre-rift Jurassic sequence reaching 800 m in thickness, composed of shallow marine carbonate platform deposits, lies unconformably over both the Triassic salt and the Paleozoic basement [START_REF] Valladares | Evolución de facies en el Jurasico calcareo del sector sur-occidental de la provincia de Burgos[END_REF][START_REF] Platt | Basin evolution and fault reactivation in the western Cameros Basin, Northern Spain[END_REF][START_REF] Aurell | Sedimentary evolution and sequence stratigraphy of the Upper Jurassic in the central Iberian Chain, northeast Spain[END_REF][START_REF] Aurell | Transgressive-regressive cycles and Jurassic palaeogeography of northeast Iberia[END_REF]. The syn-rift sequence begins with 3-6 km of fluvial to lacustrine deposits and rare unconformable marine layers of Late Jurassic to Barremian age [START_REF] Guiraud | A releasing solitary overstep model for the Late Jurassic-Early Cretaceous (Wealdian) Soria strike-slip basin (northern Spain)[END_REF][START_REF] Platt | Basin evolution and fault reactivation in the western Cameros Basin, Northern Spain[END_REF]Alonso & Mas, 1993;[START_REF] Mas | Evolución tectonosedimentaria de una cuenca extensional intraplaca: la cuenca finijurásica-eocretácica de Los Cameros (La Rioja-Soria)[END_REF][START_REF] Mas | Evolution of an intra-plate rift basin: the latest Jurassic-early Cretaceous Cameros basin (Northwest Iberian ranges, North Spain)[END_REF][START_REF] Quijada | Un ejemplo de llanura fluvio-deltaica influenciada por las mareas: el yacimiento de icnitas de Serrantes (Grupo Oncala, Berriasiense[END_REF][START_REF] Suárez González | Nuevas aportaciones sobre la influencia marina y la edad de los carbonatos de la Fm Leza en el sector de Préjano (SE de La Rioja)[END_REF]. The late Barremian to early Aptian depositional profile is characterized by lithologies typical of coastal wetlands with both freshwater and marine influences, grading laterally to alluvial and fluvio-lacustrine deposits [START_REF] Platt | Continental sedimentation in an evolving rift basin: the Lower Cretaceous of the western Cameros Basin (northern Spain)[END_REF][START_REF] Platt | Sedimentology and Tectonics of the Western Cameros Basin, Province of Burgos[END_REF]. These syn-rift deposits show that the basin was continuously shallow. The syn-rift sequence thins gradually toward the basin's flanks, where it laps onto the pre-rift Jurassic sequence (Fig. 3). An apparent northward migration of the depocenter suggests a slight asymmetry in the basin (Casas-Sainz & Gil-Imaz, 1998;[START_REF] Guimerà | Inversion of an extensional-ramp basin by a newly formed thrust: the Cameros basin (N. Spain)[END_REF][START_REF] Mas | Evolución tectonosedimentaria de una cuenca extensional intraplaca: la cuenca finijurásica-eocretácica de Los Cameros (La Rioja-Soria)[END_REF][START_REF] Omodeo-Salé | Tectono-stratigraphic evolution of an inverted extensional basin: the Cameros Basin (north of Spain)[END_REF], 2017). This northward migration of the depocenter likely indicates that simple shear deformation was concentrated along a detachment fault. This fault was reactivated as a reverse fault during the Pyrenean compression, inducing the northward thrusting of the Cameros basin onto the Ebro flexural basin (Fig. 3) [START_REF] Omodeo-Salé | Tectono-stratigraphic evolution of an inverted extensional basin: the Cameros Basin (north of Spain)[END_REF].

The Cameros basin is characterised by (1) the perfect continuity of the pre-rift Jurassic sequence, that is not fragmented along the reactivated detachment (Fig. 3), (2) the absence of normal faulting affecting both basement and cover (Fig. 3) and ( 3) a lack of significant offset of the top of the basement [START_REF] Casas-Sainz | Stress field and thrust kinematics: a model for the tectonic inversion of the cameros massif (Spain)[END_REF][START_REF] Casas Sainz | Oblique tectonic inversion and basement thrusting in the Cameros Massif (Northern Spain)[END_REF]Casas-Sainz & Gil-Imaz, 1998;[START_REF] Casas | Intra-plate deformation and basin formation during the Tertiary at the Northern Iberian Plate: origin and evolution of the Almazán Basin[END_REF][START_REF] Casas | Multidisciplinary approach to an extensional syncline model for the Mesozoic Cameros Basin (N Spain)[END_REF][START_REF] Omodeo-Salé | Tectono-stratigraphic evolution of an inverted extensional basin: the Cameros Basin (north of Spain)[END_REF]. The basin has therefore been interpreted as an extensional ramp syncline, formed above a décollement in the Late Triassic evaporites rooting at depth on a blind south-dipping extensional ramp or crustal detachment [START_REF] Mas | Evolución tectonosedimentaria de una cuenca extensional intraplaca: la cuenca finijurásica-eocretácica de Los Cameros (La Rioja-Soria)[END_REF][START_REF] Mas | Evolution of an intra-plate rift basin: the latest Jurassic-early Cretaceous Cameros basin (Northwest Iberian ranges, North Spain)[END_REF][START_REF] Guimerà | Inversion of an extensional-ramp basin by a newly formed thrust: the Cameros basin (N. Spain)[END_REF]Casas-Sainz & Gil-Imaz, 1998;[START_REF] Casas | Multidisciplinary approach to an extensional syncline model for the Mesozoic Cameros Basin (N Spain)[END_REF][START_REF] García-Lasanta | Remagnetizations used to unravel large-scale fold kinematics: A case study in the Cameros Basin (Northern Spain): Unfolding in Basin Inversion[END_REF][START_REF] Omodeo-Salé | Subsidence and thermal history of an inverted Late Jurassic-Early Cretaceous extensional basin (Cameros, North-central Spain) affected by very low-to low-grade metamorphism[END_REF]. This interpretation explains the northward migration of the syn-rift depocenter and associated edgeward onlap onto the pre-rift deposits, and the development of a synformal rift basin (Fig. 3). The pre-rift Jurassic deposits were stretched by this fault movement, but remained continuous [START_REF] Casas | Multidisciplinary approach to an extensional syncline model for the Mesozoic Cameros Basin (N Spain)[END_REF]. The Triassic evaporite layer accommodated most of the shear strain during extension, leaving both cover and basement well preserved. The resulting basinward gliding of the pre-rift cover was accompanied by thinning of the Triassic evaporites and by salt diapirism [START_REF] Casas Sainz | Oblique tectonic inversion and basement thrusting in the Cameros Massif (Northern Spain)[END_REF]Casas-Sainz & Gil-Imaz, 1998;[START_REF] Rat | Tectonothermal Evolution of the Cameros Basin: Implications for Tectonics of North Iberia[END_REF].

The Cameros syn-rift basin exhibits effects of HT/LP metamorphism in its deepest part, with temperatures that reached around 350-400°C (Fig. 3E) [START_REF] Guiraud | A releasing solitary overstep model for the Late Jurassic-Early Cretaceous (Wealdian) Soria strike-slip basin (northern Spain)[END_REF]Golberg et al., 1988;[START_REF] Rat | Tectonothermal Evolution of the Cameros Basin: Implications for Tectonics of North Iberia[END_REF]. The rifting stage developed under a high thermal gradient estimated at around 70°C/km, assuming a sediment thickness of 8 km [START_REF] Mata | Thermal history during Mesozoic extension and Tertiary uplift in the Cameros Basin, northern Spain[END_REF][START_REF] Del Río | Timing of diagenesis and very low-grade metamorphism in the eastern sector of the Sierra de Cameros (Iberian Range, Spain): a U-Pb SHRIMP study on monazite: U-Pb dating of diagenetic and low-grade monazite from the Iberian Range (Spain)[END_REF]. Toward the basin's northern edge, the palaeogeothermal gradient decreases to 41.5°C/km, along with the intensity of the HT/LP metamorphism (Fig. 3F) [START_REF] Omodeo-Salé | Subsidence and thermal history of an inverted Late Jurassic-Early Cretaceous extensional basin (Cameros, North-central Spain) affected by very low-to low-grade metamorphism[END_REF]. This lower thermal gradient is consistent with an estimated heat flow of approximately 60-65 mW/m 2 [START_REF] Omodeo-Salé | Subsidence and thermal history of an inverted Late Jurassic-Early Cretaceous extensional basin (Cameros, North-central Spain) affected by very low-to low-grade metamorphism[END_REF]. The HT/LP metamorphism reached its peak temperature during the early post-rift stage and developed coevally with continental breakup in the North Pyrenean Zone basins (Golberg et al., 1988;Casquet et al., 1992;Casas-Sainz & Gil-Imaz, 1998;[START_REF] Mata | Thermal history during Mesozoic extension and Tertiary uplift in the Cameros Basin, northern Spain[END_REF].

Parentis Basin

The E-W elongated Parentis basin lies between the Landes High [START_REF] Ferrer | Effects of Pyrenean contraction on salt structures of the offshore Parentis Basin (Bay of Biscay)[END_REF] to the south and the Armorican Arc to the north [START_REF] Lefort | Of what is the centre of the Ibero-Armorican arc composed?[END_REF]. This wedge-shaped basin opens westward to the eastern edge of the Bay of Biscay continental margin characterized by exhumed subcontinental mantle at the ocean-continent transition (Fig. 1) (Pinet et al., 1987;[START_REF] Bois | Major geodynamic processes studied from the ECORS deep seismic profiles in France and adjacent areas[END_REF][START_REF] Bois | Deep Seismic Investigation in the Parentis Basin (Southwestern France)[END_REF]Jammes, 2009;[START_REF] Tugend | Formation and deformation of hyperextended rift systems: Insights from rift domain mapping in the Bay of Biscay-Pyrenees[END_REF]. The south edge of the basin is defined by the north-dipping Ibis fault (Fig. 4; [START_REF] Ferrer | [END_REF]. The continental crust of the future Parentis basin underwent several extensional deformations during the Permian to Early Triassic period [START_REF] Dardel | Une circulation de fluides de haute-température à l'origine du métamorphisme crétacé nord-pyrénéen[END_REF][START_REF] Mathieu | Histoire géologique du sous-bassin de Parentis[END_REF][START_REF] Ferrer | Effects of Pyrenean contraction on salt structures of the offshore Parentis Basin (Bay of Biscay)[END_REF][START_REF] Biteau | The Aquitaine Basin[END_REF]. Extension was accompanied by the deposition of a 1-3 km thick sequence of Late Triassic to Early Jurassic evaporites (Fig. 4D; [START_REF] Curnelle | Evolution structuro-sédimentaire du Trias et de l'Infra-Lias d'Aquitaine[END_REF][START_REF] Ferrer | Effects of Pyrenean contraction on salt structures of the offshore Parentis Basin (Bay of Biscay)[END_REF]. The basin was subsequently filled with a 10 km thick sequence of pre-rift Jurassic and Early Cretaceous syn-rift shallow platform carbonates and terrigenous sediments that rests upon the Late Triassic evaporites (Fig. 4D; Montadert & Winnock, 1971;[START_REF] Bourrouilh | The North Pyrenean Aquitaine Basin, France: Evolution and Hydrocarbons[END_REF][START_REF] Bois | Geologic contribution of the Bay of Biscay deep seismic survey: a summary of the main scientific results, a discussion of the open questions and suggestions for further investigation[END_REF]. Tectonic subsidence occurred in the Parentis basin during a latest Jurassic to Early Albian syn-rift stage, followed by post-rift thermal subsidence during a latest Albian to Late Cretaceous post-rift stage [START_REF] Brunet | Subsidence in the Parentis Basin (Aquitaine, France): Implications of the Thermal Evolution[END_REF][START_REF] Ferrer | The deep seismic reflection MARCONI-3 profile: Role of extensional Mesozoic structure during the Pyrenean contractional deformation at the eastern part of the Bay of Biscay[END_REF].

The Parentis basin is characterised by a hyperextended continental crust with a Moho depth of about 10 km in the thinnest portion [START_REF] Bois | Major geodynamic processes studied from the ECORS deep seismic profiles in France and adjacent areas[END_REF][START_REF] Bois | The evolution of the layered lower crust and the Moho through geological time in Western Europe: contribution of deep seismic reflection profiles[END_REF][START_REF] Ferrer | The deep seismic reflection MARCONI-3 profile: Role of extensional Mesozoic structure during the Pyrenean contractional deformation at the eastern part of the Bay of Biscay[END_REF]. The overall basin geometry shows gently dipping margins lacking major normal fault scarps (Fig. 4D). The lower continental crust appears to be absent or very thin in the hyperextended domain, while the proximal margins include both upper and lower crust (Fig. 4D; Pinet et al., 1987b;[START_REF] Marillier | Deep structure of the Aquitaine shelf: constraints from expanding spread profiles on the ECORS Bay of Biscay transect[END_REF]Tomassino & Marillier, 1997;[START_REF] Ruiz | Caracterització estructural i sismotectònica de la litosfera en el domini Pirenaico-Cantàbric a partir de mètodes de sísmica activa i passiva[END_REF]. A positive Bouguer gravity anomaly coincides with the hyperextended domain of the Parentis rift basin (Pinet et al., 1987a), which originated during the latest Jurassic to Early Cretaceous rifting affecting the peri-Pyrenean realm [START_REF] Jammes | Tectono-sedimentary evolution related to extreme crustal thinning ahead of a propagating ocean: Example of the western Pyrenees[END_REF][START_REF] Tugend | Characterizing and identifying structural domains at rifted continental margins: application to the Bay of Biscay margins and its Western Pyrenean fossil remnants[END_REF].

The ECORS deep seismic profiling project documented the symmetrical synclinal shape of the Parentis basin and the paucity of normal faults in the stretched crust as well as in the proximal rift margins (Fig. 4D) (Pinet et al., 1987b;[START_REF] Bois | Geologic contribution of the Bay of Biscay deep seismic survey: a summary of the main scientific results, a discussion of the open questions and suggestions for further investigation[END_REF][START_REF] Bois | Deep Seismic Profiling of the Crust and Evolution of the[END_REF]. Once the syn-rift stage was well established, the Parentis basin sedimentary profile became slightly asymmetrical in response to simple shear localization along a crustal detachment during Albian time (Fig. 4D; Pinet et al., 1987a;Jammes, 2009). This evolution stage is comparable to the one identified in the Arzacq basin [START_REF] Issautier | Structural inheritance and salt tectonics controlling pseudosymmetric rift formation during Early Cretaceous hyperextension of the Arzacq and Tartas Basins (southwest France)[END_REF]. The southern and northern margins of the rift have been interpreted by various workers as parts of an asymmetric opening system (Jammes et al., 2010a(Jammes et al., , 2010b(Jammes et al., , 2010c;;[START_REF] Masini | The tectonosedimentary evolution of a hyper-extended rift basin: the example of the Arzacq-Mauléon rift system (Western Pyrenees, SW France)[END_REF][START_REF] Tugend | Formation and deformation of hyperextended rift systems: Insights from rift domain mapping in the Bay of Biscay-Pyrenees[END_REF]. However, Pinet et al. (1987b) argued that the location and the geometry of the thinned zone make it difficult to apply a classical simple shear model to the Parentis basin. They proposed that mantle uplift induced stretching (i.e. active rifting) and ductile flow in the lower crust and consequently a decoupling between the upper and lower crust. This depth-dependent crustal thinning explains the discrepancy between the slight extension at the surface and the substantial thinning of the lower/middle crust (thinning ratio greater than 6) at depth (Fig. 4D). This interpretation implies that the crust beneath the Parentis basin reached the ductile strain regime and was thinned under high-temperature conditions, as was the case in the adjacent North Pyrenean Zone. Finally, according to various authors, the Parentis basin first developed as a latest Jurassic-Aptian symmetrical rift that became asymmetrical when thinning progressively occurred through simple shear concentrated along a ductile crustal shear zone during Albian time. This suggests that the processes responsible for the Parentis basin continental crust thinning bear similarities with the ones defined in the Arzacq and Cameros syn-rift basins. Jammes et al. (2010c) highlighted the major role played by the thick pre-rift salt sequence in decoupling the deformation between the basement and the rest of the Mesozoic sedimentary cover. The southern margin of the Parentis basin underwent gravity-driven cover gliding followed by syn-rift thin-skinned extensional faulting along a décollement plane within the salt (Fig. 4D; [START_REF] Tugend | Formation and deformation of hyperextended rift systems: Insights from rift domain mapping in the Bay of Biscay-Pyrenees[END_REF]. This process induced the development of syn-rift salt anticlines and welded diapirs affecting the Mesozoic sedimentary pile (Fig. 4D; [START_REF] Mathieu | Histoire géologique du sous-bassin de Parentis[END_REF]Mediavilla, 1987;[START_REF] Ferrer | The deep seismic reflection MARCONI-3 profile: Role of extensional Mesozoic structure during the Pyrenean contractional deformation at the eastern part of the Bay of Biscay[END_REF]. Moreover, [START_REF] Ferrer | Evolution of salt structures during extension and inversion of the Offshore Parentis Basin (Eastern Bay of Biscay)[END_REF] reported that salt structures are mainly localised on basin flanks (Fig. 2).

Columbrets basin

The Columbrets offshore basin is the southwestern part of the Valencia Trough between Spain and the Balearic Islands (Figs. 1 & 5A). This ENE-WSW trending basin represents a mildly inverted and thus exceptionally preserved hyperextended rift of Late Jurassic to Early Cretaceous age (Fig. 5; e.g., [START_REF] Etheve | Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)[END_REF]. The pre-rift and syn-rift successions occupy a large-scale synclinal basin with thinned borders, shaped by displacement along extensional detachments (Figs. 5D-E). This domain underwent a polyphase rifting history that spanned three major rifting events. During the Late Permian to Early Triassic, distributed deformation formed an intracontinental rift basin filled by continental deposits [START_REF] Arche | Origin of the Permian-Triassic Iberian Basin, centraleastern Spain[END_REF][START_REF] Vargas | A comparison of the Iberian and Ebro Basins during the Permian and Triassic, eastern Spain: A quantitative subsidence modelling approach[END_REF]. This first rifting stage was followed by a Late Triassic-Early Jurassic rifting event related to the opening of the Alpine-Ligurian Tethys [START_REF] Jiménez-Munt | Lithospheric structure of the Gorringe Bank: Insights into its origin and tectonic evolution[END_REF][START_REF] Frizon De Lamotte | The southernmost margin of the Tethys realm during the Mesozoic and Cenozoic: Initial geometry and timing of the inversion processes: TETHYS SOUTHERNMOST MARGIN[END_REF][START_REF] Schettino | Tectonic history of the western Tethys since the Late Triassic[END_REF]. The climax of this rifting event was marked by the deposition of a thick layer of evaporites that became a major décollement during subsequent events [START_REF] Ortí | El Keuper del levante español[END_REF][START_REF] Ortí | Triassic evaporites of Iberia: Sedimentological and palaeogeographical implications for the western Neotethys evolution during the Middle Triassic-Earliest Jurassic[END_REF]. The Jurassic post-rift sequence is mainly composed of shallow-water limestone (e.g., [START_REF] Roca | La cubeta mesozoica de las Columbrets: aportaciones al conocimiento de la estructura del surco de Valencia[END_REF]. Partial crustal thinning occurred during the first rifting stage [START_REF] Salas | Evolution of the Mesozoic central Iberian Rift System and its Cainozoic inversion (Iberian chain)[END_REF][START_REF] Nebot | Structure of an inverted basin from subsurface and field data: the Late Jurassic-Early Cretaceous Maestrat Basin (Iberian Chain)[END_REF][START_REF] Etheve | Le bassin de Valence à la frontière des domaines ibérique et méditerranéen: Evolution tectonique et sédimentaire du Mésozoïque au Cénozoïque[END_REF][START_REF] Etheve | Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)[END_REF][START_REF] Roma | Formation and inversion of salt-detached ramp-syncline basins. Results from analog modeling and application to the Columbrets Basin (Western Mediterranean)[END_REF].

The main rifting stage leading to the hyperthinning of the continental crust in the Columbrets basin (Fig. 5D) occurred during the Late Jurassic to early Albian. The syn-rift succession consists of platform carbonate deposits, which grade basinward into deep-water marl and give way locally toward the basin's flanks to fluvial and deltaic deposits (Etheve et al., 2018 and references therein). The platform limestones preserve the record of post-rift thermal subsidence from the middle Albian to the Late Cretaceous [START_REF] Salas | Evolution of the Mesozoic central Iberian Rift System and its Cainozoic inversion (Iberian chain)[END_REF][START_REF] Nebot | Structure of an inverted basin from subsurface and field data: the Late Jurassic-Early Cretaceous Maestrat Basin (Iberian Chain)[END_REF][START_REF] Etheve | Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)[END_REF].

The Moho depth is 25-30 km under the margins of the Columbrets basin and only 8-10 km under the central portion (Fig. 5A; [START_REF] Gallart | Features of deep crustal structure and the onshore-offshore transition at the Iberian flank of the Valencia Trough (Western Mediterranean)[END_REF][START_REF] Banda | The Valencia trough (western Mediterranean): An overview[END_REF][START_REF] Dañobeitia | Deep crustal configuration of the Valencia trough and its Iberian and Balearic borders from extensive refraction and wide-angle reflection seismic profiling[END_REF][START_REF] Torné | The Valencia Trough: Geological and geophysical constraints on the basin formation model[END_REF][START_REF] Vidal | Contribution of the ESCI-Valencia Trough wide-angle data to a crustal transect in the NE Iberian margin[END_REF][START_REF] Ayala | The lithosphere-asthenosphere boundary in the western Mediterranean from 3D joint gravity and geoid modeling: tectonic implications[END_REF][START_REF] Ayala | A review of the current knowledge of the crustal and lithospheric structure of the Valencia Trough Basin[END_REF][START_REF] Gomez-Ortiz | Crustal structure from gravity signatures in the Iberian Peninsula[END_REF][START_REF] Etheve | Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)[END_REF]. The thickness of the continental crust reaches a minimum of 3.5 km in the hyperextended domain (Fig. 5D; [START_REF] Etheve | Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)[END_REF], where it coincides with an unusually strong Bouguer gravity anomaly ranging in amplitude between 60 and 80 mGal (Fig. 5B; [START_REF] Ayala | A review of the current knowledge of the crustal and lithospheric structure of the Valencia Trough Basin[END_REF]. Both features are consistent with the shallowing of the lithosphere-asthenosphere boundary (60-65 km depth) indicated by geoid modelling and 3-D gravity data consistent with extreme crustal thinning [START_REF] Zeyen | Integrated lithospheric modeling combining thermal, gravity, and local isostasy analysis: Application to the NE Spanish Geotransect[END_REF][START_REF] Ayala | The lithosphere-asthenosphere boundary of the Valencia Trough (western Mediterranean) deduced from 2D Geoid and Gravity Modelling[END_REF][START_REF] Ayala | The lithosphere-asthenosphere boundary in the western Mediterranean from 3D joint gravity and geoid modeling: tectonic implications[END_REF][START_REF] Carballo | Thermal and petrophysical characterization of the lithospheric mantle along the northeastern Iberia geo-transect[END_REF].

The Columbrets basin has been interpreted as a salt-detached syn-rift ramp-syncline basin [START_REF] Roma | Formation and inversion of salt-detached ramp-syncline basins. Results from analog modeling and application to the Columbrets Basin (Western Mediterranean)[END_REF]. The eastern side of the basin features an extensional detachment fault, rooting at depth in the continental crust beneath the hyperextended rift domain (Figs. 5D-E; [START_REF] Etheve | Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)[END_REF] that coincides with the Triassic salt décollement. This detachment is responsible for the overall thin-skinned extensional deformation of the pre-rift sedimentary cover experiencing basinward halokinetic gliding [START_REF] Etheve | Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)[END_REF]. Nevertheless, finite motion along the detachment imaged in seismic reflection profiles is not enough to account for the extreme crustal thinning identified in the basin core and the large discrepancy in thinning ratios between the lower and upper crust [START_REF] Etheve | Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)[END_REF]. In fact, the reflective lower crust becomes thinner toward the axis of the Columbrets basin, where it appears to be either absent or no thicker than 1-2 km [START_REF] Gallart | Features of deep crustal structure and the onshore-offshore transition at the Iberian flank of the Valencia Trough (Western Mediterranean)[END_REF][START_REF] Gallart | Lateral variations in the deep crustal structure at the Iberian margin of the Valencia trough imaged from seismic reflection methods[END_REF][START_REF] Dañobeitia | Deep crustal configuration of the Valencia trough and its Iberian and Balearic borders from extensive refraction and wide-angle reflection seismic profiling[END_REF][START_REF] Torné | Crustal and velocity structure of the Valencia trough (western Mediterranean), Part I. A combined refraction/ wide-angle reflection and near-vertical reflection study[END_REF][START_REF] Sàbat | Role of extension and compression in the evolution of the eastern margin of Iberia: The ESCI-València trough seismic profile[END_REF][START_REF] Vidal | Contribution of the ESCI-Valencia Trough wide-angle data to a crustal transect in the NE Iberian margin[END_REF]. These observations highlight the differences in the rheological response of the upper and lower crust to crustal stretching as deduced from the Parentis basin architecture. [START_REF] Etheve | Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)[END_REF] suggested that the lower crust underwent large-scale ductile deformation/boudinage during the Late Jurassic to Early Cretaceous syn-rift stage followed by simple shear along a single crustal detachment at the end of the syn-rift stage. In summary, the evolution of the Columbrets rift system was controlled by shallow decoupling in the Triassic pre-rift evaporites and deep decoupling in the middle crust [START_REF] Etheve | Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)[END_REF]. Thus, its syn-rift evolution shares similarities with the behaviour of the Arzacq, Cameros and Parentis basins, which first experienced homogeneous ductile crustal thinning of the lower crustal levels passing to the activation of a shallower crustal detachment.

The present-day surface heat flow in the southwestern Valencia Trough is about 65 to 100 mW/m 2 (e.g., [START_REF] Ayala | A review of the current knowledge of the crustal and lithospheric structure of the Valencia Trough Basin[END_REF][START_REF] Carballo | Thermal and petrophysical characterization of the lithospheric mantle along the northeastern Iberia geo-transect[END_REF]. That area also displays the thinnest continental crust section [START_REF] Banda | The Valencia trough (western Mediterranean): An overview[END_REF][START_REF] Fernandez | Evidence for the multi-stage formation of the south-western Valencia Trough[END_REF][START_REF] Ayala | A review of the current knowledge of the crustal and lithospheric structure of the Valencia Trough Basin[END_REF], demonstrating that a stable high thermal regime was inherited from the Late Jurassic to Cretaceous rifting despite the fact that rifting ended in the Cenozoic.

North Pyrenean Zone basins

In the Pyrenees, late Hercynian (Permian) post-orogenic extension led to the development of continental deposits in endorheic extensional basins [START_REF] Bixel | Magmatisme, tectonique et sédimentation dans les fossés stéphano-permiens des Pyrénées occidentales[END_REF], 1987;[START_REF] Bixel | Le volcanisme stéphano-permien des Pyrénées[END_REF]. At the same time, magmatic and granulitic rocks were exhumed all along the North Pyrenean Zone [START_REF] De Saint Blanquat | La faille normale ductile du massif du Saint Barthélémy. Evolution hercynienne des massifs nord-pyrénéens catazonaux considérée du point de vue de leur histoire thermique[END_REF][START_REF] Olivier | Gneiss domes and granite emplacement in an obliquely convergent regime: New interpretation of the Variscan Agly Massif (Eastern Pyrenees, France)[END_REF][START_REF] Cochelin | Champ de déformation du socle paléozoïque des Pyrénées[END_REF][START_REF] Cochelin | Vertical strain partitioning in hot Variscan crust: Syn-convergence escape of the Pyrenees in the Iberian-Armorican syntax[END_REF]Saspiturry et al., 2019b). A consequence of the Hercynian collapse stage was major thinning of previously hot lithosphere, an important structural inheritance regarding the following Mesozoic stages. Recent studies have proposed that the continental crust was partly thinned before the onset of Early Cretaceous hyperextension. Restorations of Iberian-European crustal sections across the Mauléon basin (western Pyrenees) and the Ballongue basin (central Pyrenees) show that the Moho was already very shallow (~20 km depth) by the end of the Jurassic [START_REF] Asti | How Do Continents Deform During Mantle Exhumation? Insights From the Northern Iberia Inverted Paleopassive Margin, Western Pyrenees (France)[END_REF][START_REF] Espurt | Crustal-scale balanced cross-section and restorations of the Central Pyrenean belt (Nestes-Cinca transect): Highlighting the structural control of Variscan belt and Permian-Mesozoic rift systems on mountain building[END_REF]Saspiturry et al., 2020a). Thus, the latest Paleozoic thinning stage, as well as the Late Triassic regional extensional stage, should not be neglected when estimating the Cretaceous thinning in the North Pyrenean Zone.

The Triassic deposits of the Western Pyrenees are typical of the German-type succession, ending with a thick evaporite and ophite complex [START_REF] Curnelle | Evolution structuro-sédimentaire du Trias et de l'Infra-Lias d'Aquitaine[END_REF][START_REF] Lucas | Le grès rouge du versant nord des Pyrénées: essai sur la géodynamique de dépôts continentaux du permien et du trias[END_REF][START_REF] Rossi | Datation U-Pb sur zircons des dolérites tholéiitiques pyrénéennes (ophites) à la limite Trias-Jurassique et relations avec les tufs volcaniques dits « infra-liasiques » nord-pyrénéens[END_REF]. The salt unit has played a major role in the Pyrenees, acting as a décollement layer at the base of the Mesozoic sedimentary cover that controlled the deformational style during Early Cretaceous hyperextension [START_REF] Canérot | anifestations de l'halocinèse dans les chaînons béarnais ( one Nord-Pyrénéenne) au Crétacé inférieur[END_REF][START_REF] Canérot | Rifting éocrétacé et halocinèse sur la marge ibérique des Pyrénées Occidentales (France). Conséquences structurales[END_REF][START_REF] Canérot | Diapirisme crétacé sur la marge ibérique des Pyrénées occidentales; exemple du pic de Lauriolle; comparaisons avec l'Aquitaine, les Pyrénées centrales et orientales[END_REF][START_REF] James | Diapirisme et structuration post-triasique des Pyrénées occidentales et de l'Aquitaine méridionale (France)[END_REF][START_REF] Canérot | Mesozoic diapirism in the Pyrenean orogen: Salt tectonics on a transform plate boundary[END_REF]Jammes et al., 2010b;[START_REF] Lagabrielle | Mantle exhumation, crustal denudation, and gravity tectonics during Cretaceous rifting in the Pyrenean realm (SW Europe): Insights from the geological setting of the lherzolite bodies[END_REF][START_REF] Lagabrielle | A review of cretaceous smooth-slopes extensional basins along the Iberia-Eurasia plate boundary: How pre-rift salt controls the modes of continental rifting and mantle exhumation[END_REF][START_REF] Duretz | Numerical modelling of Cretaceous Pyrenean Rifting: The interaction between mantle exhumation and syn-rift salt tectonics[END_REF]. Unlike the previously described basins, the North Pyrenean Zone typically lacks Berriasian and Valanginian deposits [START_REF] Combes | Altérites et bauxites, témoins des marges européenne et ibérique des Pyrénées occidentales au Jurassique supérieur-Crétacé inférieur, à l'ouest de la vallée d'Ossau (Pyrénées-Atlantiques, France)[END_REF][START_REF] James | La plate-forme carbonatée ouest-pyrénéenne au jurassique moyen et supérieur stratigraphie séquentielle, stades d'évolution, relations avec la subsurface en aquitaine méridionale[END_REF][START_REF] Canérot | Les Pyrénées: Histoire géologique[END_REF], a witness of the emersion of the area during the earliest Cretaceous. From Barremian to Aptian times, the Iberian and European margins of the North Pyrenean Zone basins were carbonate platforms grading to distal marls toward the basin axis. In summary, the North Pyrenean Zone hyperextended basins are characterised by sedimentary sequences consisting of ( 1) Late Triassic to Early Jurassic pre-rift evaporites 1-3 km thick [START_REF] Curnelle | Evolution structuro-sédimentaire du Trias et de l'Infra-Lias d'Aquitaine[END_REF], (2) Jurassic pre-rift carbonate platform rocks 0.5-2 km thick deposited in a relatively stable tectonic context [START_REF] Delfaud | Evolution des bassins jurassiques dans la zone nordpyrénéenne occidentale[END_REF][START_REF] Lenoble | Les plates-formes carbonatées ouest-pyrénéennes du dogger à l'Albien, stratigraphie séquentielle et évolution géodynamique[END_REF][START_REF] James | La plate-forme carbonatée ouest-pyrénéenne au jurassique moyen et supérieur stratigraphie séquentielle, stades d'évolution, relations avec la subsurface en aquitaine méridionale[END_REF], ( 3) Barremian to Aptian syn-rift carbonates and marls up to 1.6 km thick [START_REF] Delfaud | Evolution des bassins pendant le Crétacé inférieur dans les Pyrénees occidentales et la bordure de l'Aquitaine[END_REF][START_REF] Arnaud-Vanneau | Paléogéographie des calcaires urgoniens du sud de la France[END_REF], (4) syn-rift Albian flysch-like deposits (the Black Flysch or "Flysch Ardoisier") 1-5 km thick [START_REF] Debroas | Evolution de la fosse du flysch ardoisier de l'Albien superieur au Senonien inferieur (zone interne metamorphique des Pyrenees navarrolanguedociennes)[END_REF][START_REF] Debroas | odèle de bassin triangulaire à l'intersection de décrochements divergents pour le fossé albo-cénomanien de la Ballongue (zone nord-pyrénéenne, France)[END_REF][START_REF] Debroas | Le flysch noir albo-cenomanien temoin de la structuration albienne a senonienne de la Zone nord-pyreneenne en Bigorre (Hautes-Pyrenees, France)[END_REF][START_REF] Boirie | Etude Sédimentologique des Poudingues de Mendibelza (Pyrénées Atlantiques)[END_REF][START_REF] Boirie | Les poudingues de Mendibelza: dépôts de cônes sousmarins du rift albien des Pyrénées[END_REF]Fixari, 1984;[START_REF] Roux | Recherches stratigraphiques et sédimentologiques sur les flyschs crétacés pyrénéens au sud d'Oloron (Pyrénées Atlantiques)[END_REF][START_REF] Souquet | Le groupe du Flysch noir (albo-cénomanien) dans les Pyrénées[END_REF][START_REF] Debroas | Les brèches d'Urdach, témoins de l'exhumation du manteau pyrénéen dans un escarpement de faille vraconniencénomanien inférieur (Zone nord-pyrénéenne, Pyrénées-Atlantiques, France)[END_REF] and ( 5) post-rift turbidites 2-4 km thick [START_REF] Casteras | Carte géologique de la France à 1/50 000: feuille de Tardets-Sorholus[END_REF][START_REF] Henry | Carte géologique de la France au 1/50 000: feuille d'Orthe[END_REF][START_REF] Pochat | Carte géologique de France au 1/50 000[END_REF][START_REF] Razin | Evolution tecto-sédimentaire alpine des Pyrénées basques à l'ouest de la transformante de Pamplona[END_REF].

In this section we discuss the reconstructed architecture of the Mauléon and Basque-Cantabrian basins, together with that of basins present within the Internal Metamorphic Zone.

We show that similarly to the previously described basins, the North Pyrenean Zone basins is affected by a syn-rift stage characterised by pure shear ductile thinning of the lower middle crust. The North Pyrenean Zone basins are characterised by the presence of positive Bouguer gravity anomalies above their inverted hyperextended domain, as evidenced by the Basque-Cantabrian, Mauléon and Saint-Gaudens anomalies (Fig. 6). These anomalies reflect the presence of subcontinental mantle at shallow depth that was exhumed during the climax of the Mesozoic extension. With the exception of the Columbrets basin, the North Pyrenean Zone rift basins record continental breakup and mantle exhumation from the latest Albian to Early Cenomanian (breakup sequence, sensu [START_REF] Soares | The breakup sequence and associated lithospheric breakup surface: their significance in the context of rifted continental margins (West Iberia and Newfoundland margins, North Atlantic)[END_REF].

Mauléon basin

The Mauléon basin, located south of the Arzacq basin (Figs. 1 &7), coincides with a strong positive gravity anomaly centred upon the basin axis (Figs. 6 & 7A;[START_REF] Gottis | Construction d'un modèle géodynamique pyrénéen[END_REF][START_REF] Boillot | La zone nord-pyrénéenne, ses prolongements sur la marge continentale nord-espagnole et sa signification structurale[END_REF]. First interpreted as lower crustal material [START_REF] Grandjean | Etude des structures crustales dans une portion de chaîne et de leur relation avec les bassins sédimentaires. Application aux Pyrénées occidentales[END_REF][START_REF] Vacher | A three-dimensional model of the Pyrenean deep structure based on gravity modelling, seismic images and petrological constraints[END_REF][START_REF] Pedreira | Three-dimensional gravity and magnetic modeling of crustal indentation and wedging in the western Pyrenees-Cantabrian Mountains[END_REF], the anomaly is currently attributed to the presence at shallow depth (~10 km) of a dome of subcontinental mantle (Fig. 7B; [START_REF] Casas | Gravity anomaly map of the Pyrenean region and a comparison of the deep geological structure of the western and eastern Pyrenees[END_REF]Jammes et al., 2010a). This interpretation has gained support from recent work documenting P-wave velocities of ~7.3 km/s in this deep material (Fig. 7B; [START_REF] Wang | The deep roots of the western Pyrenees revealed by full waveform inversion of teleseismic P waves[END_REF][START_REF] Chevrot | The non-cylindrical crustal architecture of the Pyrenees[END_REF].

Above the mantle dome, the thickness of the crust is assumed to be roughly 5 km (Fig. 7B).

Mantle exhumation apparently occurred during Cretaceous hyperextension, when the

Mauléon basin developed as a hyperextended rift [START_REF] Jammes | Tectono-sedimentary evolution related to extreme crustal thinning ahead of a propagating ocean: Example of the western Pyrenees[END_REF][START_REF] Lagabrielle | Mantle exhumation, crustal denudation, and gravity tectonics during Cretaceous rifting in the Pyrenean realm (SW Europe): Insights from the geological setting of the lherzolite bodies[END_REF][START_REF] Masini | The tectonosedimentary evolution of a hyper-extended rift basin: the example of the Arzacq-Mauléon rift system (Western Pyrenees, SW France)[END_REF][START_REF] Tugend | Formation and deformation of hyperextended rift systems: Insights from rift domain mapping in the Bay of Biscay-Pyrenees[END_REF][START_REF] Corre | Deformation associated with mantle exhumation in a distal, hot passive margin environment: New constraints from the Saraillé Massif (Chaînons Béarnais, North-Pyrenean Zone)[END_REF][START_REF] Teixell | The crustal evolution of the west-central Pyrenees revisited: Inferences from a new kinematic scenario[END_REF]Lagabrielle et al., 2019a;[START_REF] Labaume | Evolution of salt structures of the Pyrenean rift (Chaînons Béarnais, France): From hyper-extension to tectonic inversion[END_REF]. The basin was inverted during Eocene shortening and is a pop-up structure at present, bordered to the north and south by conjugate thrusts (Fig. 7B; Saspiturry et al., 2020a).

The Mauléon basin began as a symmetric syn-rift basin that subsided in response to pure shear ductile thinning of the lower/middle crust during the Early Cretaceous (Saspiturry et al., 2019a) (Fig. 7E). Its structural style changed from Albian to early Cenomanian time, leading to asymmetric basin morphology and sedimentary facies distribution. Gravity-flow conglomerates accumulated at the foot of the Iberian margin slope, forming the Mendibelza fan conglomerates [START_REF] Boirie | Etude Sédimentologique des Poudingues de Mendibelza (Pyrénées Atlantiques)[END_REF]Fixari, 1984;[START_REF] Souquet | Le groupe du Flysch noir (albo-cénomanien) dans les Pyrénées[END_REF], in response to activity on steep north-dipping normal faults (South Arbailles and North Arbailles faults; Saspiturry et al., 2019a). These rocks originated in fan deltas reworking freshly uplifted Paleozoic substratum. Restoration of syn-rift geometries indicates that the Iberian substratum was tilted 30° toward the north in Albian time (Saspiturry et al., 2019a). This implies a thickening of syn-rift deposits to the north toward the steep south-dipping Saint-Palais fault, where the conglomerates reach a maximum thickness of around 5 km (Fig. 7). This fault separated the marls of the central basin from the European proximal margin to the north, where a carbonate platform developed (Saspiturry et al., 2019a). The gentle southward slope of the European margin contrasts with the steep northward slope of the Iberian margin. This geometry points to the Saint-Palais fault as a major normal fault that was responsible for the change to asymmetric basin margins during Albian to early Cenomanian time. In this scheme, the steep north-dipping slope of the Iberian margin can be interpreted as a rollover structure in the hanging-wall of the Saint-Palais fault. The rollover structure is also accommodated by minor north-dipping normal faults that propagated toward the south.

Facies distribution significantly changed from the mid-Cenomanian to the late Santonian in the Mauléon basin as shallow carbonate platforms developed on the Iberian and European margins [START_REF] Souquet | Le groupe du Flysch noir (albo-cénomanien) dans les Pyrénées[END_REF][START_REF] Alhamawi | Sédimentologie, pétrographie sédimentaire et diagenèse des calcaires Crétacé supérieur de la marge ibérique[END_REF][START_REF] Ternet | Carte géologique de la France au 1/50 000[END_REF][START_REF] Serrano | Le bassin d'Aquitaine: valorisation des données sismiques, cartographie structurale et potentiel pétrolier[END_REF]. On the European side, the transition from platform to basin coincided with the steep south-dipping South Grand Rieu fault (Fig. 7). The Iberian carbonate platform graded northward rather abruptly to deep-sea calcareous breccias at the site of the Lakhoura normal fault, which appears to have acted as a significant northward detachment during mid-Cenomanian times. This detachment, responsible for a southward tilt of the Iberian basement, crosscuts the lower part of the older Saint-Palais structure, which was inactive at that time. Thus, the Mauléon basin was affected by ductile pure shear thinning of the lower/middle crust from the Barremian to the Aptian, followed by Albian simple shear concentrated along two major crustal detachments: (1) the south-verging Saint-Palais fault accommodating the thinning of the European margin and (2) the north-verging Lakhoura detachment crosscutting the Saint-Palais fault (Fig. 7C3). Along strike, the Mauléon basin was affected by continental breakup from the latest Albian to the Early Cenomanian (Fig. 7D) as evidenced by the presence of subcontinental mantle clasts into the latest Albian to Early Cenomanian Urdach breccias [START_REF] Roux | Recherches stratigraphiques et sédimentologiques sur les flyschs crétacés pyrénéens au sud d'Oloron (Pyrénées Atlantiques)[END_REF][START_REF] Duée | Les lherzolites associées aux Chaînons Béarnais (Pyrénées Occidentales): Mise à l'affleurement anté-dogger et resédimentation albo-cénomanienne[END_REF][START_REF] Fortané | Lherzolites and the western "Chaînons éarnais" (French Pyrenees): Structural and paleogeographical pattern[END_REF][START_REF] Debroas | Les brèches d'Urdach, témoins de l'exhumation du manteau pyrénéen dans un escarpement de faille vraconniencénomanien inférieur (Zone nord-pyrénéenne, Pyrénées-Atlantiques, France)[END_REF] as well as by the formation of ophicalcites at the surface of the denudated mantle [START_REF] Jammes | Tectono-sedimentary evolution related to extreme crustal thinning ahead of a propagating ocean: Example of the western Pyrenees[END_REF][START_REF] Lagabrielle | Mantle exhumation, crustal denudation, and gravity tectonics during Cretaceous rifting in the Pyrenean realm (SW Europe): Insights from the geological setting of the lherzolite bodies[END_REF]Lagabrielle et al., , 2019a;;[START_REF] Debroas | Les brèches d'Urdach, témoins de l'exhumation du manteau pyrénéen dans un escarpement de faille vraconniencénomanien inférieur (Zone nord-pyrénéenne, Pyrénées-Atlantiques, France)[END_REF].

Rifting and continental breakup in the Mauléon basin developed, from the Early Cretaceous to the mid-Cenomanian (Fig. 7E), under a high geothermal gradient, as indicated by ( 1) Raman spectroscopy of carbon materials (RSCM) showing peak temperatures consistent with a gradient of 60-75°C/km [START_REF] Corre | La bordure nord de la plaque ibérique à l'Albo-Cénomanien: architecture d'une marge passive de type ductile (Chaînons Béarnais[END_REF]Saspiturry, 2019;[START_REF] Saspiturry | Paleogeothermal Gradients across an Inverted Hyperextended Rift System: Example of the Mauléon Fossil Rift (Western Pyrenees)[END_REF], (2) detrital zircon fission-track data indicating a 80°C/km gradient [START_REF] Vacherat | Thermal imprint of rift-related processes in orogens as recorded in the Pyrenees[END_REF] and ( 3) (U-Th-Sm)/He thermochronology data indicating a 80-100°C/km gradient [START_REF] Hart | Thermal evolution of a hyperextended rift basin, Mauléon Basin, western Pyrenees: Thermal evolution of hyperextended rift[END_REF].

Numerical thermal models suggest that the base of the hyperextended domain had a mantle heat flow of 100 mW/m 2 and a maximum temperature of 600°C during continental breakup (Saspiturry, 2019;[START_REF] Saspiturry | Paleogeothermal Gradients across an Inverted Hyperextended Rift System: Example of the Mauléon Fossil Rift (Western Pyrenees)[END_REF]. Vitrinite reflectance values from the Mauléon basin also weigh in favour of HT/LP syn-rift metamorphism [START_REF] Lescoutre | Formation and reactivation of the Pyrenean-Cantabrian rift system : inheritance, segmentation and thermal evolution[END_REF][START_REF] Lescoutre | Formation and reactivation of the Pyrenean-Cantabrian rift system : inheritance, segmentation and thermal evolution[END_REF]. It should be noted that the peak temperature was reached in the lower part of the basin during the post-rift period [START_REF] Vacherat | Thermal imprint of rift-related processes in orogens as recorded in the Pyrenees[END_REF]Saspiturry, 2019), similar to the Cameros basin. Due to Pyrenean thrusting, a detached slice of mantle rock crops out in the eastern part of the basin (Urdach area). In that location, crustal material in contact with the Urdach lherzolites shows ductile shearing, suggesting that the upper/middle crust was extruded laterally from the basin axis at temperatures between 350°C and 450°C [START_REF] Asti | How Do Continents Deform During Mantle Exhumation? Insights From the Northern Iberia Inverted Paleopassive Margin, Western Pyrenees (France)[END_REF]. Hydrothermal fluid circulation sheds light on the ductile shearing of the Mauléon basin pre-rift cover during continental breakup at ~94 Ma [START_REF] Incerpi | Characteristics and timing of hydrothermal fluid circulation in the fossil Pyrenean hyperextended rift system: new constraints from the Chaînons Béarnais (W Pyrenees)[END_REF]. The thermal regime of the Mauléon basin from the end of the syn-rift stage (Albian, Fig. 7E) to the breakup sequence (latest Albian to Early Cenomanian; Fig. 7E) attests a ductilely stretched sedimentary cover and crystalline basement.

Basque-Cantabrian basin

The Basque-Cantabrian basin records a similar Mesozoic history as the North Pyrenean Zone rift basins, although it developed to the eastern termination and south of the Pyrenean Axial Zone (AZ in Fig. 1). The rift axis is characterised by a succession of Upper Jurassic and Cretaceous sediments around 8-10 km thick with interlayered basic volcanic rocks of Aptian to Santonian age (Figs. 8A-B; [START_REF] Azambre | Le magmatisme alcalin d'age cretace, dans les Pyrenees occidentales et l'Arc basque; ses relations avec le metamorphisme et la tectonique[END_REF][START_REF] Rat | Vue sur le Cretacé basco-cantabrique et nord-ibérique. Une Marge Son Arriere-Pays Ses Environ[END_REF][START_REF] Rat | The Basque-Cantabrian Basin between the Iberian and European plates, some facts but still many problems[END_REF]García Mondéjar et al., 1996;[START_REF] Castañares | Distribución estratigráfica de los episodios volcánicos submarinos del Albiense-Santoniense en la Cuenca Vasca (sector Gernika-Plentzia[END_REF][START_REF] Castañares | El vulcanismo del Albiense-Santoniense en la Cuenca Vasco-Cantábrica[END_REF]). The lithosphere is extremely thin in the western central part of the basin, as suggested by a positive Bouguer anomaly recorded in the Biscay Synclinorium (Fig. 6; [START_REF] Pedreira | Three-dimensional gravity and magnetic modeling of crustal indentation and wedging in the western Pyrenees-Cantabrian Mountains[END_REF] that is interpreted as the consequence of lithospheric mantle exhumed at shallow depth (Figs. 8A-B; [START_REF] Pedrera | [END_REF][START_REF] Pedrera | The Getxo crustal-scale cross-section: testing tectonic models in the Bay of Biscay-Pyrenean rift system[END_REF][START_REF] Garcia-Senz | Inversion of the North-Iberian hyperextended margin: the role of exhumed mantle indentation during continental collision[END_REF]. Field observations and seismic interpretations indicate that the Basque-Cantabrian basin has an overall symmetric shape characterised by brittle deformation on its flanks and ductile deformation on its axis [START_REF] Defelipe | Mantle exhumation and metamorphism in the Basque-Cantabrian Basin (NSpain): Stable and clumped isotope analysis in carbonates and comparison with ophicalcites in the North-Pyrenean Zone (Urdach and Lherz)[END_REF][START_REF] Pedrera | Reconstruction of the exhumed mantle across the North Iberian Margin by crustal-scale 3-D gravity inversion and geological cross section[END_REF][START_REF] Ducoux | The Nappe des Marbres unit of the Basque-Cantabrian Basin: the tectono-thermal evolution of a fossil hyperextended rift basin[END_REF].

The basin continental crust was stretched during the Early Cretaceous rifting stage. Locally, mantle denudation occurred during early Cenomanian continental breakup as revealed by the presence of a strongly weathered mantle fragment near the inverted Leiza major detachment fault [START_REF] Mendia | High-grade metamorphic rocks and peridotites along the Leiza Fault (Western Pyrenees, Spain)[END_REF][START_REF] Defelipe | Mantle exhumation and metamorphism in the Basque-Cantabrian Basin (NSpain): Stable and clumped isotope analysis in carbonates and comparison with ophicalcites in the North-Pyrenean Zone (Urdach and Lherz)[END_REF][START_REF] Ducoux | Structure, thermicité et évolution géodynamique de la Zone Interne Métamorphique des Pyrénées[END_REF][START_REF] Ducoux | The Nappe des Marbres unit of the Basque-Cantabrian Basin: the tectono-thermal evolution of a fossil hyperextended rift basin[END_REF].

Hyperextension was also recorded by the development of Cretaceous HT/LP metamorphism [START_REF] Golberg | High temperature-low pressure Cretaceous metamorphism related to crustal thinning (Eastern North Pyrenean Zone, France)[END_REF][START_REF] Cuevas | The discovery of scapolite marbles in the Biscay Synclinorium (Basque-Cantabrian basin, Western Pyrenees): geodynamic implications[END_REF]. Mineral assemblages and RSCM data from the Nappes des Marbres, which represents the inverted eastern part of the Basque-Cantabrian basin, indicate that temperature in the pre-rift sedimentary cover locally reached 500-600°C during hyperextension (Figs. 8C-D;[START_REF] Lamare | Recherches géologiques dans les Pyrénées basques d'Espagne[END_REF][START_REF] Martínez-Torres | El manto de los mármoles (Pirineo occidental): geología estructural y evolución geodinámica[END_REF][START_REF] Mendia | High-grade metamorphic rocks and peridotites along the Leiza Fault (Western Pyrenees, Spain)[END_REF][START_REF] Ducoux | The Nappe des Marbres unit of the Basque-Cantabrian Basin: the tectono-thermal evolution of a fossil hyperextended rift basin[END_REF]. Thus, the felsic crust and its sedimentary cover underwent ductile stretching during the Albian syn-rift stage and Cenomanian continental breakup. Interpretations of geophysical data have shown that decoupling between basement and cover rocks occurred in low-strength Triassic evaporites and mudstones and induced coeval formation of cover gliding, mini-basins, turtle salt anticlines, expulsion rollovers, and salt diapirs in the cover strata (Fig. 8; [START_REF] Pedrera | Reconstruction of the exhumed mantle across the North Iberian Margin by crustal-scale 3-D gravity inversion and geological cross section[END_REF], Ducoux et al., 2019;[START_REF] Cámara | Inverted turtle salt anticlines in the Eastern Basque-Cantabrian basin, Spain[END_REF]. The association of exhumed mantle along the Leiza fault with rift and postrift structural geometries suggests that a major south-dipping ramp-flat-ramp extensional detachment was active from Albian to early Cenomanian time [START_REF] Lagabrielle | A review of cretaceous smooth-slopes extensional basins along the Iberia-Eurasia plate boundary: How pre-rift salt controls the modes of continental rifting and mantle exhumation[END_REF].

Internal Metamorphic Zone basins

The central and eastern portions of the North Pyrenean Zone include a narrow Internal Metamorphic Zone along their southern borders (Fig. 1). They consist of a east-west-trending stretched zone of Variscan basement and pre-rift to syn-rift metamorphic rocks [START_REF] Casteras | Recherches sur la structure du versant nord des Pyrénées centrales et orientales[END_REF][START_REF] Mattauer | Les traits structuraux essentiels de la chaîne Pyrénéenne[END_REF][START_REF] Choukroune | Structure et évolution tectonique de la zone nord-pyrénéenne: analyse de la déformation dans une portion de chaîne à schistosité sub-verticale[END_REF] with several outcrops of subcontinental mantle rocks [START_REF] Monchoux | Les lher olites pyrénéennes: contribution à l'étude de leur minéralogie, de leur genèse et de leurs transformations[END_REF][START_REF] Choukroune | Tectonique des plaques et Pyrenees; sur le fonctionnement de la faille transformante nord-pyreneenne; comparaisons avec des modeles actuels[END_REF][START_REF] Fabriès | Evolution of the Upper Mantle beneath the Pyrenees: Evidence from Orogenic Spinel Lherzolite Massifs[END_REF][START_REF] Fabriès | Petrogenetic evolution of orogenic lherzolite massifs in the central and western Pyrenees[END_REF][START_REF] Lagabrielle | Mantle exhumation, crustal denudation, and gravity tectonics during Cretaceous rifting in the Pyrenean realm (SW Europe): Insights from the geological setting of the lherzolite bodies[END_REF]. Recent studies have shown that the Internal Metamorphic Zone is an inverted domain of continental crust that was hyperextended during Early Cretaceous rifting [START_REF] Lagabrielle | Submarine reworking of exhumed sub-continental mantle rocks: field evidence from the Lherz peridotites, French Pyrenees: Cretaceous exhumation of pyrenean mantle[END_REF][START_REF] Lagabrielle | Mantle exhumation, crustal denudation, and gravity tectonics during Cretaceous rifting in the Pyrenean realm (SW Europe): Insights from the geological setting of the lherzolite bodies[END_REF][START_REF] Clerc | [END_REF]Clerc et al., 2014[START_REF] Clerc | [END_REF][START_REF] De | Northwest-Iberia margin[END_REF][START_REF] Teixell | Crustal structure and evolution of the Pyrenean-Cantabrian belt: A review and new interpretations from recent concepts and data[END_REF][START_REF] Dielforder | Formation of the Iberian-European Convergent Plate Boundary Fault and Its Effect on Intraplate Deformation in Central Europe[END_REF][START_REF] Espurt | Crustal-scale balanced cross-section and restorations of the Central Pyrenean belt (Nestes-Cinca transect): Highlighting the structural control of Variscan belt and Permian-Mesozoic rift systems on mountain building[END_REF][START_REF] Garcia-Senz | Inversion of the North-Iberian hyperextended margin: the role of exhumed mantle indentation during continental collision[END_REF]). In the central Pyrenees, the Internal Metamorphic Zone coincides with the Saint-Gaudens positive Bouguer anomaly (Fig. 9A) and corresponds to the inverted Early Cenomanian continental breakup domain (Figs. 9B-C).

It has been shown that the whole continental crust of the North Pyrenean Zone was affected by large-scale ductile boudinage during Early Cretaceous hyperextension, with E-W trending rift basins exhibiting a relatively symmetrical profile [START_REF] Clerc | High-temperature metamorphism during extreme thinning of the continental crust: a reappraisal of the North Pyrenean passive paleomargin[END_REF][START_REF] Lagabrielle | A review of cretaceous smooth-slopes extensional basins along the Iberia-Eurasia plate boundary: How pre-rift salt controls the modes of continental rifting and mantle exhumation[END_REF]. The presence of a thick pre-rift salt layer led to basinward gliding of the overlying Jurassic cover during hyperextension [START_REF] Lagabrielle | Mantle exhumation, crustal denudation, and gravity tectonics during Cretaceous rifting in the Pyrenean realm (SW Europe): Insights from the geological setting of the lherzolite bodies[END_REF][START_REF] Clerc | [END_REF][START_REF] Clerc | High-temperature metamorphism during extreme thinning of the continental crust: a reappraisal of the North Pyrenean passive paleomargin[END_REF][START_REF] Duretz | Numerical modelling of Cretaceous Pyrenean Rifting: The interaction between mantle exhumation and syn-rift salt tectonics[END_REF][START_REF] Lagabrielle | A review of cretaceous smooth-slopes extensional basins along the Iberia-Eurasia plate boundary: How pre-rift salt controls the modes of continental rifting and mantle exhumation[END_REF].

Evidence of HT/LP metamorphism has been reported along the entire North Pyrenean Zone [START_REF] Ravier | Le métamorphisme des terrains secondaires des Pyrénées[END_REF]Albarède & Michard-Vitrac, 1978a, 1978b;Golberg et al., 1988;Golberg & Maluski, 1988;[START_REF] Golberg | High temperature-low pressure Cretaceous metamorphism related to crustal thinning (Eastern North Pyrenean Zone, France)[END_REF][START_REF] Clerc | High-temperature metamorphism during extreme thinning of the continental crust: a reappraisal of the North Pyrenean passive paleomargin[END_REF]. This metamorphism resulted from Early Cretaceous continental-crust thinning and an associated increase in thermal gradient and burial [START_REF] Choukroune | Tectonique des plaques et Pyrenees; sur le fonctionnement de la faille transformante nord-pyreneenne; comparaisons avec des modeles actuels[END_REF][START_REF] Vielzeuf | Crustal splitting and the emplacement of Pyrenean lherzolites and granulites[END_REF][START_REF] Debroas | Le flysch noir albo-cenomanien temoin de la structuration albienne a senonienne de la Zone nord-pyreneenne en Bigorre (Hautes-Pyrenees, France)[END_REF][START_REF] Clerc | High-temperature metamorphism during extreme thinning of the continental crust: a reappraisal of the North Pyrenean passive paleomargin[END_REF]. RSCM peak temperatures reached 400-600°C in the marbles of the Internal Metamorphic Zone, where some of the highest temperatures were recorded close to exhumed mantle outcrops (Fig. 9D; [START_REF] Clerc | Evolution du domaine nord-pyrénéen au Crétacé: amincissement crustal extrême et thermicite élevée: un analogue pour les marges passives[END_REF][START_REF] Clerc | High-temperature metamorphism during extreme thinning of the continental crust: a reappraisal of the North Pyrenean passive paleomargin[END_REF][START_REF] Boulvais | Fluid generation in the Boucheville Basin as a consequence of the North Pyrenean metamorphism[END_REF][START_REF] Chelalou | New sedimentological, structural and paleo-thermicity data in the Boucheville Basin (eastern North Pyrenean Zone, France)[END_REF][START_REF] Lagabrielle | Very high geothermal gradient during mantle exhumation recorded in mylonitic marbles and carbonate breccias from a Mesozoic Pyrenean palaeomargin (Lherz area, North Pyrenean Zone, France)[END_REF][START_REF] Ducoux | Structure, thermicité et évolution géodynamique de la Zone Interne Métamorphique des Pyrénées[END_REF]. During the Albian syn-rift stage and the Early Cenomanian breakup event, the crust was homogeneously and ductilely stretched in the hyperextended domain, while detachment faults at the transition between the mantle and the crust/sedimentary cover accommodated the thinning of the whole system (Lagabrielle et al., 2019a). Likewise, mineral assemblages indicate that maximum temperatures of 550-650°C and pressures of 3-4 kbar were reached locally [START_REF] Bernus-Maury | Etude des paragéneses caractéristiques du métamorphisme mésozoïque dans la partie orientale des Pyrénées[END_REF][START_REF] Golberg | High temperature-low pressure Cretaceous metamorphism related to crustal thinning (Eastern North Pyrenean Zone, France)[END_REF][START_REF] Vauchez | Preorogenic exhumation of the North Pyrenean Agly massif (Eastern Pyrenees-France)[END_REF]. Previous authors have established that this metamorphic event was linked to high syn-rift geothermal gradients (Dauteuil & Ricou, 1989;[START_REF] Golberg | High temperature-low pressure Cretaceous metamorphism related to crustal thinning (Eastern North Pyrenean Zone, France)[END_REF][START_REF] Clerc | High-temperature metamorphism during extreme thinning of the continental crust: a reappraisal of the North Pyrenean passive paleomargin[END_REF][START_REF] Lagabrielle | Very high geothermal gradient during mantle exhumation recorded in mylonitic marbles and carbonate breccias from a Mesozoic Pyrenean palaeomargin (Lherz area, North Pyrenean Zone, France)[END_REF]. All the basins reviewed in this work are characterised by a strong heterogeneous structural pattern inherited from the Late Carboniferous to Triassic rifting events related to the collapse of the Variscan belt and the breakup of Pangea. These events ended with the deposition of ~1-3 km thick Late Triassic to Early Jurassic salt deposits. Thus, Mesozoic hyperextension initiated within a continental crust that was previously thinned to less than 30 km thick (Fig. 10A). Unfortunately, the precise thickness of the crust at the end of the Triassic remains undetermined. The Late Jurassic to Early Cretaceous syn-rift stage was driven by distributed deformation characterised by the lateral extraction of the lower/middle crust (Fig. 10B).

During this stage, thinning of the lower/middle crust triggered progressive subsidence. Our review shows that homogeneous subsidence was partly balanced by the production of syn-rift carbonates in most of the studied basins. The result is a relatively smooth basin floor profile characterised by carbonate platform deposits with marls in a central trough. During this early stage, the basin was symmetric and marked by edgeward onlap of the syn-rift deposits (Fig. 10B). The pre-rift cover was efficiently decoupled from its substratum thanks to the thick layer of Keuper evaporites at its base. This rheological layering and the progressive sinking of the central part of the rift system eventually led to the breakup of the pre-rift lid on the external margins of the basin. This resulted in a large-scale pre-rift cover which remained in the central part of the extensional system throughout the whole basin lifetime, while the continental crust was progressively thinned below it (Fig. 10B andC). In contrast to all other reviewed basins, the Tartas basin exemplifies this syn-rift stage since continental crust thinning was not followed by the activation of extensional detachments, allowing the basin floor profile to remain symmetric. During this first rift regime, the upper crust might have been affected by very minor brittle deformation beneath the salt décollement level that led to superficial salt diapirism affecting the pre-rift to syn-rift sedimentary cover (Fig. 10B), as evidenced in the Arzacq [START_REF] Issautier | Structural inheritance and salt tectonics controlling pseudosymmetric rift formation during Early Cretaceous hyperextension of the Arzacq and Tartas Basins (southwest France)[END_REF], Parentis [START_REF] Ferrer | Evolution of salt structures during extension and inversion of the Offshore Parentis Basin (Eastern Bay of Biscay)[END_REF], Columbrets [START_REF] Etheve | Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)[END_REF], and Mauléon [START_REF] Canérot | Mesozoic diapirism in the Pyrenean orogen: Salt tectonics on a transform plate boundary[END_REF] basins during Late Jurassic to Aptian time. However, during this syn-rift stage, continental crustal thinning was mainly accommodated by distributed ductile thinning within the lower/middle continental crust. This process was first suggested in the case of the Parentis basin (Pinet et al., 1987a). It was then put forward by Clerc and Lagabrielle (2014) in their interpretation of the architecture of the eastern North Pyrenean Zone basins and used by [START_REF] Corre | Deformation associated with mantle exhumation in a distal, hot passive margin environment: New constraints from the Saraillé Massif (Chaînons Béarnais, North-Pyrenean Zone)[END_REF] in the reconstruction of the eastern Mauléon basin border. It has more recently been applied to the central Mauléon basin (Saspiturry et al., 2019a;[START_REF] Asti | How Do Continents Deform During Mantle Exhumation? Insights From the Northern Iberia Inverted Paleopassive Margin, Western Pyrenees (France)[END_REF], Arzacq basin [START_REF] Issautier | Structural inheritance and salt tectonics controlling pseudosymmetric rift formation during Early Cretaceous hyperextension of the Arzacq and Tartas Basins (southwest France)[END_REF] and Columbrets basin [START_REF] Etheve | Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)[END_REF]. It consists of a distributed thinning stage in which the lower/middle crust was homogeneously and symmetrically thinned without major brittle deformation of the upper crust. Interpretation of seismic profiles sheds light on the wide discrepancy in thinning ratios between the lower and upper crust in the Columbrets [START_REF] Etheve | Basque-Cantabrian basin (Azambre & Rossy[END_REF] and Parentis (Pinet et al., 1987a) basins as they were slightly inverted. Such a discrepancy in the amount of continental thinning has been numerically modelled and defined as depth-dependent continental crust thinning [START_REF] Huismans | Complex rifted continental margins explained by dynamical models of depth-dependent lithospheric extension[END_REF], 2011, 2014). This pure shear dominated thinning stage is applicable to all the North Pyrenean Zone basins since (1) their sedimentary profile was symmetric throughout the Barremian to Aptian beginning of the syn-rift stage and (2) they do not record exhumation of the lower crust during Mesozoic hyperextension in their central part (see section 2.5 for more details).

Simple shear dominated thinning

As thinning of the lower/middle crust continued, isostatic subsidence occurred in the centre of the basin. The early smooth synclinal-shape basin progressively deepened, triggering steepening of pre-to-syn-rift sequences. Deformation became localised and a simple shear regime initiated along a crustal detachment connecting upward to the Late Triassic pre-rift salt décollement. With the progression of extension, the pre-rift sequence was progressively dissected in several large-scale boudins and turtle structures separated by intervening salt diapirs (Fig. 10C andD). The top basement surface is steeper in the basin flanks than in the basin core, therefore portions of the pre-rift cover may undergone gravity-driven gliding leading to local syn-extensional thrusting (layer-parallel shortening). From a general point of view, gliding was controlled by thickness variations of the sedimentary pile that cause differential loading on the salt layer [START_REF] Lundin | Thin-skinned extensional tectonics on a salt detachment, northern Kwanza Basin, Angola[END_REF][START_REF] Liro | Salt deformation history and postsalt structural trends, offshore southern Gabon[END_REF][START_REF] Rouby | Kinematics of a growth fault/raft system on the West African margin using 3-D restoration[END_REF] and basinward tilting of the proximal margin [START_REF] Cobbold | Radial gravitational gliding on passive margins[END_REF][START_REF] Demercian | Style and pattern of salt diapirs due to thin-skinned gravitational gliding, Campos and Santos basins, offshore Brazil[END_REF][START_REF] Gaullier | Raft tectonics: the effects of residual topography below a salt deīcollement[END_REF]Fort et al., 2004aFort et al., , 2004b)). The gravity gliding unroofed the basement of the proximal rift margin. As the pre-rift and syn-rift sequences glided along the décollement, salt was expelled both marginward and basinward as well as upward by buoyancy. Thus, in the reviewed basins, halokinesis led to (1) the development of saltdetachment synclines, salt rollovers or diapirs affecting and controlling syn-rift depocentres and (2) the denudation of the proximal margin basement that was subsequently overlain by syn-rift sediments. This scenario is reported from most of the studied basins.

(1) In the Arzacq basin, the southern margin recorded northward cover gliding (Fig. 2; [START_REF] Issautier | Structural inheritance and salt tectonics controlling pseudosymmetric rift formation during Early Cretaceous hyperextension of the Arzacq and Tartas Basins (southwest France)[END_REF].

(2) In the Parentis basin, major diapirism (Pelican borehole, Fig. 4D; [START_REF] Ferrer | The deep seismic reflection MARCONI-3 profile: Role of extensional Mesozoic structure during the Pyrenean contractional deformation at the eastern part of the Bay of Biscay[END_REF][START_REF] Ferrer | Effects of Pyrenean contraction on salt structures of the offshore Parentis Basin (Bay of Biscay)[END_REF][START_REF] Ferrer | Evolution of salt structures during extension and inversion of the Offshore Parentis Basin (Eastern Bay of Biscay)[END_REF] and denudation of its southern margin basement (Fig. 4D: Jammes, 2019) were documented.

(3) In the Columbrets basin, the SE margin basement was denudated [START_REF] Etheve | Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)[END_REF].

(4) In the Mauléon basin, the proximal margin basement was locally denudated on both edges of the rift (Fig. 7C3 & 7D; [START_REF] Teixell | The crustal evolution of the west-central Pyrenees revisited: Inferences from a new kinematic scenario[END_REF]Saspiturry et al., 2020a).

(5) In the Basque-Cantabrian basin, the prerift cover was removed from its proximal margins (Fig 8A; [START_REF] Pedrera | Reconstruction of the exhumed mantle across the North Iberian Margin by crustal-scale 3-D gravity inversion and geological cross section[END_REF].

(6) In the Internal Metamorphic Zone, the pre-rift allochthonous cover remained in its central part (Fig. 9C-D; [START_REF] Espurt | Crustal-scale balanced cross-section and restorations of the Central Pyrenean belt (Nestes-Cinca transect): Highlighting the structural control of Variscan belt and Permian-Mesozoic rift systems on mountain building[END_REF].

Denudation of the basement proximal margin has also appeared in thermo-mechanical numerical models of lithospheric-scale extension that integrate recent data collected along the North Pyrenean Zone basins [START_REF] Duretz | Numerical modelling of Cretaceous Pyrenean Rifting: The interaction between mantle exhumation and syn-rift salt tectonics[END_REF]. This process resulted in the formation of syn-gliding wedge-shaped sedimentary geometries and syn-rift sequence depocenter migration, as seen in (a) the Arzacq and Parentis basins, which display southward syn-rift depocenter migration (Fig. 2 and 4D; Jammes, 2009;[START_REF] Issautier | Structural inheritance and salt tectonics controlling pseudosymmetric rift formation during Early Cretaceous hyperextension of the Arzacq and Tartas Basins (southwest France)[END_REF], and (b) the Cameros, Columbrets and Mauléon basins which display northward, north-westward and northward syn-rift depocenter migration, respectively (Figs. 3F, 4D and 7C2-C3;[START_REF] Omodeo-Salé | Tectono-stratigraphic evolution of an inverted extensional basin: the Cameros Basin (north of Spain)[END_REF][START_REF] Etheve | Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)[END_REF]Saspiturry et al., 2020a). In the Mauléon basin, the increasing northward slope-deepening of the Iberian margin is interpreted as a rollover effect linked to the Saint-Palais detachment. Increasing tilting of the Iberian margin led to cover gliding, immediately followed by the accumulation of deep basin gravity deposits. These latter consist of reworked sediment from rafts of the pre-rift sedimentary cover and the freshly exposed proximal margin basement [START_REF] Teixell | The crustal evolution of the west-central Pyrenees revisited: Inferences from a new kinematic scenario[END_REF]Saspiturry et al., 2019a;[START_REF] Labaume | Evolution of salt structures of the Pyrenean rift (Chaînons Béarnais, France): From hyper-extension to tectonic inversion[END_REF]. A similar evolution cannot be clearly reconstructed for the Basque-Cantabrian and Internal Metamorphic Zone basins, which experienced severe inversion during the compressional stages of the Pyrenean orogeny (e.g. Pedrera et al., 2017, Fig. 8A;Espurt et al., 2019, Fig. 9C). In contrast to the Tartas basin, which did not reach the second syn-rift extensional stage, all the other basins became asymmetric, as evidenced by shifts of the basin depocenter.

Seismic profiles display clear images of crustal detachments in the Parentis (Fig. 4D; Jammes, 2009;Jammes et al., 2010c;[START_REF] Tugend | Formation and deformation of hyperextended rift systems: Insights from rift domain mapping in the Bay of Biscay-Pyrenees[END_REF] [START_REF] Ayala | A review of the current knowledge of the crustal and lithospheric structure of the Valencia Trough Basin[END_REF][START_REF] Etheve | Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)[END_REF].

Due to progressive burial and continental crust thinning, the sedimentary cover in the centre of some smooth-slope basins experienced warm thermal regimes as typically shown by the HT/LP metamorphism of the North Pyrenean Basins (more than 400°C). This is also documented in the Cameros basin by mineralogical analysis, thermochronology and fluid inclusion studies (Fig. 3F; [START_REF] Rat | Tectonothermal Evolution of the Cameros Basin: Implications for Tectonics of North Iberia[END_REF], as well as in the Columbrets basin by an elevated mantle heat flow of around 100 mW/m 2 [START_REF] Ayala | A review of the current knowledge of the crustal and lithospheric structure of the Valencia Trough Basin[END_REF][START_REF] Carballo | Thermal and petrophysical characterization of the lithospheric mantle along the northeastern Iberia geo-transect[END_REF].

Breakup stage

The North Pyrenean Basins first underwent significant pure shear ductile thinning of the lower/middle crust throughout the Barremian to Aptian, followed by simple shear localization on detachment faults during the Albian (Saspiturry et al., 2019a). In concept, continental breakup occurs once the sedimentary cover is removed from the proximal margins and the lower crust fully withdrawn from the basin centre (Fig. 10D). This results in the development of brittle deformation on the basin flanks and the formation of tilted basement blocks devoid of sedimentary cover, while the central hyperextended domain records dominantly ductile thinning and mantle exhumation (Fig. 10D). As previously shown by [START_REF] Soares | The breakup sequence and associated lithospheric breakup surface: their significance in the context of rifted continental margins (West Iberia and Newfoundland margins, North Atlantic)[END_REF], while the upper continental crust deforms in a brittle manner in the hyperextended domain during dominantly pure-shear thinning, the deformation regime switches during dominantly simple-shear thinning and subsequent mantle exhumation. As the lower and middle crust is removed from the basin centre during the syn-rift sequence, the isotherms rise under the most highly extended parts of the rift. The 300°C to 500°C isotherms can be traced above the top of the Variscan basement and overlying pre-rift and syn-rift sediments. This implies that large volumes of the basement and cover were in a ductile regime during this stage (Fig. 10D).

Thus, during the breakup sequence, thinning of the crust is first controlled by the elevation of the thermal conditions in relation with mantle exhumation. An additional parameter triggering temperature elevation is the progressive burial of the continental crust under a thick sedimentary cover that accumulates in the basin during the syn-rift stage. Both causes significantly increase the temperature at the base of the basin. This process has also been demonstrated by numerical modelling of the North Pyrenean Zone basins [START_REF] Duretz | Numerical modelling of Cretaceous Pyrenean Rifting: The interaction between mantle exhumation and syn-rift salt tectonics[END_REF]. In the hyperextended domain, extension is localised along a ductile shear zone at the transition between mantle and continental crust/sedimentary cover.

Our review highlights important characteristics of the thinning processes in the most evolved basins. We confirm that the conditions of HT/LP metamorphism evident along the hyperextended domains of the North Pyrenean basins account for the ductile behaviour of the crust. The climax of this thermal metamorphism occurred during continental breakup (Albarède & Michard-Vitrac, 1978a;[START_REF] Montigny | K-Ar Study of cretaceous magmatism and metamorphism in the Pyrenees: Age and length of rotation of the Iberian Peninsula[END_REF][START_REF] Golberg | Petrological and age relationship between emplacement of magmatic breccia, alkaline magmatism, and static metamorphism in the North Pyrenean Zone[END_REF]Golberg & Maluski, 1988;[START_REF] Thiébaut | Métamorphisme des évaporites triasiques du versant nord des Pyrénées centrales et Occidentales[END_REF]. The peak temperature reached in the Jurassic to Albian sedimentary cover varies between 500° and 600°C, as documented in various places: (1) the Mauléon basin (Figs. 7C4-D;[START_REF] Corre | La bordure nord de la plaque ibérique à l'Albo-Cénomanien: architecture d'une marge passive de type ductile (Chaînons Béarnais[END_REF]Saspiturry, 2019), (2) the Nappes des Marbres in the Basque-Cantabrian basin (Fig. 8D; [START_REF] Lamare | Recherches géologiques dans les Pyrénées basques d'Espagne[END_REF]Martínez-Torrez, 1989;[START_REF] Mendia | High-grade metamorphic rocks and peridotites along the Leiza Fault (Western Pyrenees, Spain)[END_REF][START_REF] Ducoux | Structure, thermicité et évolution géodynamique de la Zone Interne Métamorphique des Pyrénées[END_REF][START_REF] Ducoux | The Nappe des Marbres unit of the Basque-Cantabrian Basin: the tectono-thermal evolution of a fossil hyperextended rift basin[END_REF] and ( 3) the Internal Metamorphic Zone basins in the central and eastern Pyrenees (Fig. 9D; [START_REF] Bernus-Maury | Etude des paragéneses caractéristiques du métamorphisme mésozoïque dans la partie orientale des Pyrénées[END_REF][START_REF] Golberg | High temperature-low pressure Cretaceous metamorphism related to crustal thinning (Eastern North Pyrenean Zone, France)[END_REF]Azambre et al., 1992;[START_REF] Clerc | Evolution du domaine nord-pyrénéen au Crétacé: amincissement crustal extrême et thermicite élevée: un analogue pour les marges passives[END_REF][START_REF] Vauchez | Preorogenic exhumation of the North Pyrenean Agly massif (Eastern Pyrenees-France)[END_REF][START_REF] Clerc | High-temperature metamorphism during extreme thinning of the continental crust: a reappraisal of the North Pyrenean passive paleomargin[END_REF][START_REF] Chelalou | New sedimentological, structural and paleo-thermicity data in the Boucheville Basin (eastern North Pyrenean Zone, France)[END_REF].

The Internal Metamorphic Zone and the Nappes des Marbres have been interpreted as the inverted base of the North Pyrenean hyperextended rift domain [START_REF] Clerc | Evolution du domaine nord-pyrénéen au Crétacé: amincissement crustal extrême et thermicite élevée: un analogue pour les marges passives[END_REF][START_REF] Clerc | [END_REF][START_REF] Clerc | High-temperature metamorphism during extreme thinning of the continental crust: a reappraisal of the North Pyrenean passive paleomargin[END_REF][START_REF] Lagabrielle | Very high geothermal gradient during mantle exhumation recorded in mylonitic marbles and carbonate breccias from a Mesozoic Pyrenean palaeomargin (Lherz area, North Pyrenean Zone, France)[END_REF][START_REF] Ducoux | Structure, thermicité et évolution géodynamique de la Zone Interne Métamorphique des Pyrénées[END_REF]. In these settings, continental crust thinning resulted in a high geothermal gradient estimated at around 60-100°C/km in the Mauléon basin [START_REF] Vacherat | Thermal imprint of rift-related processes in orogens as recorded in the Pyrenees[END_REF][START_REF] Corre | La bordure nord de la plaque ibérique à l'Albo-Cénomanien: architecture d'une marge passive de type ductile (Chaînons Béarnais[END_REF][START_REF] Hart | Thermal evolution of a hyperextended rift basin, Mauléon Basin, western Pyrenees: Thermal evolution of hyperextended rift[END_REF]Saspiturry, 2019). The maximum temperature reached in the sedimentary cover increased from the margins to the hyperextended domain. Thus, the thermal gradient increased together with the thickness of the sedimentary pile (Saspiturry, 2019). Numerical thermal modelling has shown that this thermal gradient was associated, in the Mauléon basin, with an elevated mantle heat flow of around 100 mW/m 2 (Saspiturry, 2019). The basinward gliding of the prerift cover contributed significantly to the burial and thus to the peak temperature increase at the base of the hyperextended domain.

The coupled effects of heating by mantle exhumation and burial under the thick pre-rift (salt tectonic) to syn-rift sedimentary sequence prevented crustal normal faults from propagating into the hyperextended domain, as evidenced in the Nappes des Marbres (Fig. 8D; [START_REF] Ducoux | Mauléon basin[END_REF] and the Internal Metamorphic Zone (Fig. 9D; [START_REF] Espurt | Crustal-scale balanced cross-section and restorations of the Central Pyrenean belt (Nestes-Cinca transect): Highlighting the structural control of Variscan belt and Permian-Mesozoic rift systems on mountain building[END_REF]. Thinning of both the Variscan basement and the allochthonous sedimentary pile occurred in the hyperextended domain within a thick zone of dominantly ductile shear (Lagabrielle et al., 2019a). This process led to the formation of large-scale boudins and lenses of continental crust and strongly sheared metasedimentary rocks [START_REF] Clerc | [END_REF]Clerc et al., 2015b;[START_REF] Corre | Deformation associated with mantle exhumation in a distal, hot passive margin environment: New constraints from the Saraillé Massif (Chaînons Béarnais, North-Pyrenean Zone)[END_REF][START_REF] Asti | How Do Continents Deform During Mantle Exhumation? Insights From the Northern Iberia Inverted Paleopassive Margin, Western Pyrenees (France)[END_REF][START_REF] Duretz | Numerical modelling of Cretaceous Pyrenean Rifting: The interaction between mantle exhumation and syn-rift salt tectonics[END_REF]Lagabrielle et al., 2019a). These mature basins then took the shape of typical pseudo-symmetric hyperextended rift basins; their margins were affected by brittle normal faulting and their centres were dominated by ductile stretching as observed along the most evolved smooth-slope basins of the North Pyrenean Zone. As shown by the presence of clasts of mantle rocks in the Cretaceous turbidite breakup sequence of the Urdach area, these basins underwent local denudation of subcontinental mantle thanks to motion along a major detachment during the Late Albian to Early Cenomanian continental breakup [START_REF] Roux | Recherches stratigraphiques et sédimentologiques sur les flyschs crétacés pyrénéens au sud d'Oloron (Pyrénées Atlantiques)[END_REF][START_REF] Duée | Les lherzolites associées aux Chaînons Béarnais (Pyrénées Occidentales): Mise à l'affleurement anté-dogger et resédimentation albo-cénomanienne[END_REF][START_REF] Fortané | Lherzolites and the western "Chaînons éarnais" (French Pyrenees): Structural and paleogeographical pattern[END_REF][START_REF] Jammes | Tectono-sedimentary evolution related to extreme crustal thinning ahead of a propagating ocean: Example of the western Pyrenees[END_REF][START_REF] Debroas | Les brèches d'Urdach, témoins de l'exhumation du manteau pyrénéen dans un escarpement de faille vraconniencénomanien inférieur (Zone nord-pyrénéenne, Pyrénées-Atlantiques, France)[END_REF][START_REF] Lagabrielle | Mantle exhumation, crustal denudation, and gravity tectonics during Cretaceous rifting in the Pyrenean realm (SW Europe): Insights from the geological setting of the lherzolite bodies[END_REF]Lagabrielle et al., , 2019a, b), b). Although the Mauléon basin displays clasts of mantle rocks reworked in its breakup sequence sensu [START_REF] Soares | The breakup sequence and associated lithospheric breakup surface: their significance in the context of rifted continental margins (West Iberia and Newfoundland margins, North Atlantic)[END_REF], it underwent heterogeneous amounts of mantle denudation and seems to show a less advanced stage of continental breakup than the Basque-Cantabrian and Internal Metamorphic Zone basins. According to Saspiturry et al. (2019aSaspiturry et al. ( , 2020a)), the amount of mantle denudation under the Mauléon basin varied along strike as a consequence of Permian inheritance along N20° transverse structures (Fig. 7C3; Saspiturry et al., 2019b). It was maximal in the eastern part (Urdach) but almost nonexistent in its western part (Fig. 7D; [START_REF] Teixell | The crustal evolution of the west-central Pyrenees revisited: Inferences from a new kinematic scenario[END_REF][START_REF] Labaume | Evolution of salt structures of the Pyrenean rift (Chaînons Béarnais, France): From hyper-extension to tectonic inversion[END_REF]. In addition, the Internal Metamorphic Zone basin displayed a more advanced breakup sequence than the Basque-Cantabrian basin as evidenced by the widths of exhumed mantle along two restored crustal-balanced crosssections, which are ~45 km (Fig. 9C; [START_REF] Espurt | Crustal-scale balanced cross-section and restorations of the Central Pyrenean belt (Nestes-Cinca transect): Highlighting the structural control of Variscan belt and Permian-Mesozoic rift systems on mountain building[END_REF] and ~15 km (Fig. 8A; [START_REF] Pedrera | Reconstruction of the exhumed mantle across the North Iberian Margin by crustal-scale 3-D gravity inversion and geological cross section[END_REF] long, respectively. The Bilbao, Mauléon and Saint-Gaudens positive Bouguer anomalies (Fig. 6) represent the remains of continental breakup stages now buried at depth, as they correspond to major pieces of mantle exhumed during the latest Albian to Early Cenomanian breakup sequence and more recently inverted during the Pyrenean orogeny

(Figs. 7A-B, 8A-B & 9A-B).
Based on the observations listed in this section, we may conclude that the reviewed smoothslope extensional basins represent different degrees of hyperextension that occurred along the Iberia-Eurasia plate boundary during the Cretaceous drift of Iberia. We thus propose to rank these basins from least mature to most mature as follows: (1) Tartas, (2) Arzacq/Cameros, (3) Parentis/Columbrets, (4) Mauléon, (5) Basque-Cantabrian and (6) Internal Metamorphic Zone (Fig. 11). This ranking indicates that as the amount of extension increases in these basins, the intensity of various fundamental processes also increases. These processes are lower/middle crust lateral extraction, thermal gradient and heat flow, HT/LP metamorphism, ductile thinning of the crust and its sedimentary cover, relative gliding of the pre-rift cover and mantle exhumation.

A major consequence of all these processes is the formation of a succession of basins with smooth basement slopes, which differ significantly from rift basins controlled by dominantly normal faulting that affects both their borders and centres. These smooth-slope basins were the locus of gentle, homogeneous subsidence that led to the deposition of syn-rift flysch-like sediments a few kilometers thick. Therefore the response of the smooth-slope basins to extensional stress was the accumulation of sediments that in turn increased the thermal burial effect in the basin centres. Such burial appears to have been a key factor in the syn-rift evolution of smooth-slope basins, along with parameters that were critical earlier at the initiation of rifting, such as the Variscan-Triassic inheritance of thin crust [START_REF] Asti | How Do Continents Deform During Mantle Exhumation? Insights From the Northern Iberia Inverted Paleopassive Margin, Western Pyrenees (France)[END_REF] and the presence of a very thick (average 2 km) layer of evaporites and shale of the Keuper group that allowed the decoupling of the pre-rift cover and its stagnation within the centre of the studied basins [START_REF] Lagabrielle | A review of cretaceous smooth-slopes extensional basins along the Iberia-Eurasia plate boundary: How pre-rift salt controls the modes of continental rifting and mantle exhumation[END_REF]. Syn-rift deposits of mature smooth-slope basins are well known in the North Pyrenean Zone as the "Flysch Noir" group [START_REF] Souquet | Le groupe du Flysch noir (albo-cénomanien) dans les Pyrénées[END_REF][START_REF] Debroas | Le flysch noir albo-cenomanien temoin de la structuration albienne a senonienne de la Zone nord-pyreneenne en Bigorre (Hautes-Pyrenees, France)[END_REF]. Pioneer authors such as Ravier (1959) have shown that this sequence locally experienced HT/LP metamorphism and deduced from microstructural analysis that a large part of this evolution was static and necessarily linked to passive burial in the Flysch Noir basins. These authors clearly showed that the thermal pulse did not affect the Cenomanian sediments, leading to the concept of a "phase ante-cénomanienne" (e.g. [START_REF] Casteras | Recherches sur la structure du versant nord des Pyrénées centrales et orientales[END_REF]. In contrast, further studies pointed to the synkinematic character of some HT/LP mineral assemblages and claimed that Pyrenean metamorphism was linked to the orogenic evolution of the belt (e.g. Choukroune, 1976). Later detailed studies revisited the link between thermal metamorphism and the opening of the North Pyrenean basins (e.g. [START_REF] Golberg | High temperature-low pressure Cretaceous metamorphism related to crustal thinning (Eastern North Pyrenean Zone, France)[END_REF]. However, these studies did not consider the role of sedimentary burial. Therefore, in this review, we note the existence of pioneer works that despite the rudimentary geological knowledge of the time deduced 60 years ago that sediment burial was a key factor in the thermal evolution of the basins at the Iberia-Eurasia plate boundary.

Comparison of smooth-slope type basins with Atlantic type margins: West

Iberia and Bay of Biscay margins

Review of the timing of the main Mesozoic events and unconformities

In this section we address the timing of formation of the syn-rift, breakup, post-rift and drifting sequences in the reviewed basins as well as in the adjacent Northwest Iberia and Bay of Biscay margins (Fig. 12). As a reminder, the syn-rift, breakup, post-rift and drifting sedimentary sequences record respectively crustal thinning, mantle denudation, post-rift thermal cooling and oceanic spreading (e.g. [START_REF] Alves | Diachronous evolution of Late Jurassic-Cretaceous continental rifting in the northeast Atlantic (west Iberian margin)[END_REF][START_REF] Alves | A tectonostratigraphic review of continental breakup on intraplate continental margins and its impact on resultant hydrocarbon systems[END_REF][START_REF] Soares | The breakup sequence and associated lithospheric breakup surface: their significance in the context of rifted continental margins (West Iberia and Newfoundland margins, North Atlantic)[END_REF]Alves & Cunha, 2018). These sequences are delimited by major unconformities corresponding (from bottom to top) to the base syn-rift unconformity (BSU; base of syn-rift sequence), the lithospheric breakup surface (LBS; base of the breakup sequence) and the base post-rift unconformity (BPU; base of the post-rift sequence) as defined by [START_REF] Soares | The breakup sequence and associated lithospheric breakup surface: their significance in the context of rifted continental margins (West Iberia and Newfoundland margins, North Atlantic)[END_REF] and [START_REF] Alves | A phase of transient subsidence, sediment bypass and deposition of regressive-transgressive cycles during the breakup of Iberia and Newfoundland[END_REF].

All the reviewed basins as well as the West Iberia and Bay of Biscay margins are characterised by the onset of Mesozoic rifting between the Late Jurassic and earliest Cretaceous as they are all related to Iberia plate motion associated with the North Atlantic opening (e.g. [START_REF] Alves | Diachronous evolution of Late Jurassic-Cretaceous continental rifting in the northeast Atlantic (west Iberian margin)[END_REF][START_REF] Nirrengarten | Kinematic evolution of the southern North Atlantic: implications for the formation of hyperextended rift systems: Kinematic of hyper-extended rift systems[END_REF][START_REF] Angrand | A reconstruction of Iberia accounting for W-Tethys/N-Atlantic kinematics since the late Permian-Triassic[END_REF]. The beginning of rifting is slightly diachronous among these basins as evidenced by the timing of formation of their BSU (Fig. 12). Nearly all of the rifting sequences in the Tartas and Arzacq [START_REF] Désaglaux | Tectonic subsidence of the Aquitaine basin since Cretaceous times[END_REF][START_REF] Brunet | Subsidence et géodynamique du assin d'Aquitaine[END_REF][START_REF] Serrano | Le bassin d'Aquitaine: valorisation des données sismiques, cartographie structurale et potentiel pétrolier[END_REF][START_REF] Issautier | Structural inheritance and salt tectonics controlling pseudosymmetric rift formation during Early Cretaceous hyperextension of the Arzacq and Tartas Basins (southwest France)[END_REF], Parentis [START_REF] Brunet | Subsidence in the Parentis Basin (Aquitaine, France): Implications of the Thermal Evolution[END_REF][START_REF] Ferrer | The deep seismic reflection MARCONI-3 profile: Role of extensional Mesozoic structure during the Pyrenean contractional deformation at the eastern part of the Bay of Biscay[END_REF][START_REF] Jammes | Tectono-sedimentary evolution related to extreme crustal thinning ahead of a propagating ocean: Example of the western Pyrenees[END_REF][START_REF] Tugend | Characterizing and identifying structural domains at rifted continental margins: application to the Bay of Biscay margins and its Western Pyrenean fossil remnants[END_REF] and Columbrets [START_REF] Salas | Evolution of the Mesozoic central Iberian Rift System and its Cainozoic inversion (Iberian chain)[END_REF][START_REF] Nebot | Structure of an inverted basin from subsurface and field data: the Late Jurassic-Early Cretaceous Maestrat Basin (Iberian Chain)[END_REF][START_REF] Etheve | Le bassin de Valence à la frontière des domaines ibérique et méditerranéen: Evolution tectonique et sédimentaire du Mésozoïque au Cénozoïque[END_REF][START_REF] Etheve | Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)[END_REF][START_REF] Roma | Formation and inversion of salt-detached ramp-syncline basins. Results from analog modeling and application to the Columbrets Basin (Western Mediterranean)[END_REF]) basins end at the same time, in the Early or Middle Cenomanian (Fig. 12). The North Pyrenean Zone basins end their syn-rift sequence slightly earlier, as they are characterised by a breakup sequence developing between the latest Albian and the Early Cenomanian (Fig. 12; [START_REF] Masini | The tectonosedimentary evolution of a hyper-extended rift basin: the example of the Arzacq-Mauléon rift system (Western Pyrenees, SW France)[END_REF][START_REF] Teixell | The crustal evolution of the west-central Pyrenees revisited: Inferences from a new kinematic scenario[END_REF][START_REF] Pedrera | Reconstruction of the exhumed mantle across the North Iberian Margin by crustal-scale 3-D gravity inversion and geological cross section[END_REF][START_REF] Espurt | Crustal-scale balanced cross-section and restorations of the Central Pyrenean belt (Nestes-Cinca transect): Highlighting the structural control of Variscan belt and Permian-Mesozoic rift systems on mountain building[END_REF][START_REF] Labaume | Evolution of salt structures of the Pyrenean rift (Chaînons Béarnais, France): From hyper-extension to tectonic inversion[END_REF]. Thus, the North Pyrenean Zone basins are characterised by the development of a LBS surface (sensu [START_REF] Soares | The breakup sequence and associated lithospheric breakup surface: their significance in the context of rifted continental margins (West Iberia and Newfoundland margins, North Atlantic)[END_REF] separating the Early Cretaceous syn-rift sequence and the Latest Albian to Early Cenomanian breakup sequence. Hence the syn-rift sequence of the reviewed basins lasts around 35-45 Myr according to the timing of formation of the different basins whereas the breakup sequence of the North Pyrenean Zone basins lasts about 5 Myr (Fig. 12). In contrast to the reviewed basins, the West Iberia margins have a relatively short (~20 Myr) syn-rift sequence and a longer (~15 Myr) breakup sequence [START_REF] Soares | The breakup sequence and associated lithospheric breakup surface: their significance in the context of rifted continental margins (West Iberia and Newfoundland margins, North Atlantic)[END_REF]Pereira & Alves, 2012;Alves & Cunha, 2018;[START_REF] Alves | A tectonostratigraphic review of continental breakup on intraplate continental margins and its impact on resultant hydrocarbon systems[END_REF], and the Bay of Biscay margins have equally long syn-rift and breakup sequences (~20 Myr) (Fig. 12; Montardet et al., 1979;[START_REF] Brunet | Subsidence in the Parentis Basin (Aquitaine, France): Implications of the Thermal Evolution[END_REF][START_REF] Thinon | Structure profonde de la marge Nord Gascogne et du Bassin armoricain[END_REF][START_REF] Thinon | Pyrenean deformations in the Bay of Biscay[END_REF][START_REF] Thinon | Deep structure of the Armorican Basin (Bay of Biscay): a review of Norgasis seismic reflection and refraction data[END_REF][START_REF] Tugend | Characterizing and identifying structural domains at rifted continental margins: application to the Bay of Biscay margins and its Western Pyrenean fossil remnants[END_REF]. This is consistent with interpretations of the West Iberia margin as having a syn-rift sequence getting longer to the north and a continental breakup sequence becoming shorter to the north [START_REF] Alves | Jurassic tectonosedimentary evolution of the Northern Lusitanian Basin (offshore Portugal)[END_REF][START_REF] Alves | Mesozoic -Cenozoic evolution of North Atlantic continental slope basins: The Peniche basin, western Iberian margin[END_REF][START_REF] Alves | Diachronous evolution of Late Jurassic-Cretaceous continental rifting in the northeast Atlantic (west Iberian margin)[END_REF].

All the reviewed basins record a post-rift thermal cooling stage in which a post-rift sequence overlaps the syn-rift sequence in the Tartas, Arzacq, Cameros, Parentis and Columbrets basins and the breakup sequence in the North-Pyrenean Zone basins, where they record a more advanced Mesozoic extension. The post-rift unconformity is clearly visible in the reviewed basins as erosional truncation of the syn-rift/breakup sequences and onlap of the post-rift sequence, as seen in a seismic profile in the Arzacq (Fig. 2; [START_REF] Issautier | Structural inheritance and salt tectonics controlling pseudosymmetric rift formation during Early Cretaceous hyperextension of the Arzacq and Tartas Basins (southwest France)[END_REF], Parentis (Fig. 4D; Jammes, 2019), and Columbrets (Figs. 5C-E;[START_REF] Etheve | Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)[END_REF] basins, and in field observations in the Cameros [START_REF] Omodeo-Salé | Tectono-stratigraphic evolution of an inverted extensional basin: the Cameros Basin (north of Spain)[END_REF], 2017), Mauléon (e.g. Saspiturry et al., 2019a), Basque-Cantabrian [START_REF] Rat | The Basque-Cantabrian Basin between the Iberian and European plates, some facts but still many problems[END_REF] and Internal Metamorphic Zone [START_REF] Debroas | Evolution de la fosse du flysch ardoisier de l'Albien superieur au Senonien inferieur (zone interne metamorphique des Pyrenees navarrolanguedociennes)[END_REF][START_REF] Debroas | odèle de bassin triangulaire à l'intersection de décrochements divergents pour le fossé albo-cénomanien de la Ballongue (zone nord-pyrénéenne, France)[END_REF][START_REF] Debroas | Le flysch noir albo-cenomanien temoin de la structuration albienne a senonienne de la Zone nord-pyreneenne en Bigorre (Hautes-Pyrenees, France)[END_REF] basins. Although the North Pyrenean Zone basins underwent continental breakup, it did not progress to oceanic spreading. It is conceivable that the Pyrenean compression may have obliterated the stratigraphic evidence for a drifting stage in the North Pyrenean Zone basins. However, (1) the entire mid-Cenomanian to Late Santonian post-rift sequence is fully preserved above the North Pyrenean Zone hyperextended domain and clearly records a post-rift thermal cooling stage, (2) there is no evidence of subducted oceanic crust in a passive seismic Vp/Vs model of the Mauléon basin (Fig. 7B, [START_REF] Wang | The deep roots of the western Pyrenees revealed by full waveform inversion of teleseismic P waves[END_REF] and Internal Metamorphic Zone basins (Fig. 9B, [START_REF] Chevrot | The non-cylindrical crustal architecture of the Pyrenees[END_REF] or in a crustal-scale 3D gravity inversion of the Basque-Cantabrian basin [START_REF] Pedrera | Reconstruction of the exhumed mantle across the North Iberian Margin by crustal-scale 3-D gravity inversion and geological cross section[END_REF]. In contrast to the North Pyrenean Zone basins, oceanic spreading occurred during mid-Cenomanian time in the eastern Bay of Biscay margins (Fig. 12; [START_REF] Montadert | Northeast Atlantic passive continental margins: Rifting and subsidence processes[END_REF][START_REF] Brunet | Subsidence in the Parentis Basin (Aquitaine, France): Implications of the Thermal Evolution[END_REF][START_REF] Thinon | Structure profonde de la marge Nord Gascogne et du Bassin armoricain[END_REF][START_REF] Thinon | Pyrenean deformations in the Bay of Biscay[END_REF][START_REF] Thinon | Deep structure of the Armorican Basin (Bay of Biscay): a review of Norgasis seismic reflection and refraction data[END_REF][START_REF] Gong | The rotation of Iberia during the Aptian and the opening of the Bay of Biscay[END_REF][START_REF] Tugend | Characterizing and identifying structural domains at rifted continental margins: application to the Bay of Biscay margins and its Western Pyrenean fossil remnants[END_REF] and at the Cenomanian-Turonian boundary in the Northwest Iberia margin and western Bay of Biscay margins (Fig. 12; [START_REF] Gong | The rotation of Iberia during the Aptian and the opening of the Bay of Biscay[END_REF][START_REF] Soares | The breakup sequence and associated lithospheric breakup surface: their significance in the context of rifted continental margins (West Iberia and Newfoundland margins, North Atlantic)[END_REF]Pereira & Alves, 2012;Alves & Cunha, 2018;[START_REF] Alves | A tectonostratigraphic review of continental breakup on intraplate continental margins and its impact on resultant hydrocarbon systems[END_REF]. Although the duration of the breakup sequence differs strongly between the North Pyrenean Zone basins and the Bay of Biscay and West Iberia margins, the breakup affected all of these regions simultaneously from the mid-Cenomanian to the earliest Turonian (Fig. 12).

Architectural contrasts and discrepancies in the modes of crustal thinning

Atlantic-type margins such as West Iberia [START_REF] Boillot | Ocean-continent boundary of the Iberian margin: a serpentinite diapir west of the Galicia Bank[END_REF][START_REF] Boillot | The formation of passive margins: constraints from the crustal structure and segmentation of the deep Galicia margin, Spain[END_REF][START_REF] Reston | Detachment tectonics during Atlantic rifting: analysis and interpretation of the S reflection, the west Galicia margin[END_REF][START_REF] Whitmarsh | Evolution of magma-poor continental margins from rifting to seafloor spreading[END_REF]Péron-Pinvidic & Manatschal, 2009;Sutra et al. 2013;[START_REF] Péron-Pinvidic | Unravelling the along-strike variability of the Angola-Gabon rifted margin: a mapping approach[END_REF] or the Bay of Biscay margins (Jammes, 2009;Jammes et al., 2010aJammes et al., , 2010bJammes et al., , 2010c;;[START_REF] Tugend | Formation and deformation of hyperextended rift systems: Insights from rift domain mapping in the Bay of Biscay-Pyrenees[END_REF] are characterized by five distinctive features: (1) deformation coupling that occurs when the ductile layer has been removed and deformation in the strong and brittle upper crust couples with deformation in the strong lower crust/upper mantle, (2) detachment faults at the top of the basement that accommodate crustal extension through tilting of blocks of the basement and their pre-rift cover showing a coupled deformation, [START_REF] Tugend | Formation and deformation of hyperextended rift systems: Insights from rift domain mapping in the Bay of Biscay-Pyrenees[END_REF] formation of continental crust extensional allochthons, made up of upper crust and pre-rift cover, tectonically placed over exhumed lower crust or serpentinized mantle, (4) a wide domain of exposed subcontinental mantle at the ocean-continent transition and (5) large-scale serpentinization of the exhumed mantle that was still active at ambient seawater temperatures (Fig. 13A). Numerical models of such systems reproduce the palaeoarchitecture of the continental margins and the detachment faults responsible for crustal thinning [START_REF] Lavier | A mechanism to thin the continental lithosphere at magma-poor margins[END_REF][START_REF] Huismans | Depth-dependent extension, two-stage breakup and cratonic underplating at rifted margins[END_REF]. Numerical studies have also shown that continental crust thinning develops under conditions of high heat flow from the mantle due to asthenospheric upwelling. In these sediment-starved Atlantic-type margins, only small volumes of syn-rift sedimentary cover can be found in the hyperextended domain [START_REF] Masini | The tectonosedimentary evolution of a supra-detachment rift basin at a deep-water magma-poor rifted margin: the example of the Samedan Basin preserved in the Err nappe in SE Switzerland: Tectono-sedimentary evolution of a supra-detachment rift basin[END_REF](Masini et al., , 2012;;[START_REF] Péron-Pinvidic | Unravelling the along-strike variability of the Angola-Gabon rifted margin: a mapping approach[END_REF][START_REF] Ribes | Long-lived mega fault-scarps and related breccias at distal rifted margins: Insights from present-day and fossil analogues[END_REF] (Fig. 13A).

Palaeogeographic reconstructions [START_REF] Ziegler | Triassic rifts and facies patterns in Western and Central Europe[END_REF][START_REF] Dercourt | Geological evolution of the tethys belt from the atlantic to the pamirs since the LIAS[END_REF][START_REF] Ortí | Triassic evaporites of Iberia: Sedimentological and palaeogeographical implications for the western Neotethys evolution during the Middle Triassic-Earliest Jurassic[END_REF][START_REF] Soto | Permo-Triassic Salt Provinces of Europe, North Africa and the Atlantic Margins: Tectonics and Hydrocarbon Potential[END_REF] show that the distribution of the Pyrenean and peri-Pyrenean smooth-slope extensional basins corresponds closely to the distribution of Late Triassic evaporites and claystones [START_REF] Lagabrielle | A review of cretaceous smooth-slopes extensional basins along the Iberia-Eurasia plate boundary: How pre-rift salt controls the modes of continental rifting and mantle exhumation[END_REF]. Numerical modelling shows that these Triassic deposits played a major role at the onset of continental rifting as zones of decoupling between the Palaeozoic basement and the Jurassic to Albian sedimentary cover [START_REF] Duretz | Numerical modelling of Cretaceous Pyrenean Rifting: The interaction between mantle exhumation and syn-rift salt tectonics[END_REF]. Thus Triassic salt does not allow the coupling of the basement and its sedimentary cover during crustal extension characteristic of Atlantic-type margins. Moreover, in smooth-slope basins, the lower/middle crust is not exhumed during the breakup sequence, unlike Atlantic-type margins, as it has been laterally extracted during initial rifting. In fact, the only lower crustal rocks cropping out along the Cretaceous North Pyrenean Rift axis are quite old, having been previously exhumed during Permian time [START_REF] De Saint Blanquat | La faille normale ductile du massif du Saint Barthélémy. Evolution hercynienne des massifs nord-pyrénéens catazonaux considérée du point de vue de leur histoire thermique[END_REF][START_REF] Olivier | Gneiss domes and granite emplacement in an obliquely convergent regime: New interpretation of the Variscan Agly Massif (Eastern Pyrenees, France)[END_REF]Cochelin et al., 2018aCochelin et al., , 2018b;;Saspiturry et al., 2019b).

Finally, unlike Atlantic-type margins, the hyperextended domain of smooth-slope basins deforms under ductile conditions and HT/LP conditions due to (1) the displaced cover remaining preserved in the centre of the basin while the lower crust is thinned ductilely and

(2) the continental crust being buried under a very thick pre-rift to syn-rift sedimentary cover.

However, as in Atlantic-type margins, the proximal margins become subject to extensional brittle faulting as the crust acquires a normal thermal gradient of ~30°C/km (Saspiturry, 2019) and the proximal sedimentary cover is thinned or removed (Fig. 13B). Thus in smooth-slope basin margins, the proximal margins undergo brittle deformation while the hyperextended domain undergoes ductile thinning due to a complex interaction between salt beds, sedimentary burial and changes in the syn-rift thermal gradient (Fig. 13B). This elevated thermal regime is associated with intense metasomatism and fluid circulation affecting both the continental basement and the sedimentary cover at temperatures of 500-600°C [START_REF] Corre | Deformation associated with mantle exhumation in a distal, hot passive margin environment: New constraints from the Saraillé Massif (Chaînons Béarnais, North-Pyrenean Zone)[END_REF]Quesnel et al., 2019;Lagabrielle et al., 2019aLagabrielle et al., , 2019b)). The peak syn-rift temperature is mainly controlled by burial but can be locally influenced by fluid circulation. Indeed, adiabatic temperatures in the sedimentary cover have been interpreted as the presence of local fluid generation and convective cells in the Mauléon (Saspiturry, 2019) and Boucheville [START_REF] Boulvais | Fluid generation in the Boucheville Basin as a consequence of the North Pyrenean metamorphism[END_REF] basins.

An important difference between the two geological settings is the fact that Atlantic-type margin are sediment-starved (less than 2 km of burial) while smooth-slope basins are sediment-rich (syn-rift sequence is more than 5 km thick). In addition, in the reviewed basins, the pre-rift cover remaining in the central part of the basin, thanks to the Late Triassic salt décollement, contributes significantly to the increase in burial and thus the peak temperature at the base of the hyperextended domain by adding around 2-3 km of pre-rift sediments to preexisting syn-rift and breakup sedimentary sequences that are nearly 5 km thick. Therefore, the thinned continental basement and the exhumed mantle may be buried under 7-10 km of pre-rift to syn-breakup sediments. This allows the crust to deform in a ductile way. Finally, the pre-rift salt, which is mostly absent along Atlantic-type margins, is also a major contributor to sedimentary burial. Thus, it participates in the ductile thinning of the continental crust and its sedimentary cover, as pointed out by [START_REF] Lagabrielle | A review of cretaceous smooth-slopes extensional basins along the Iberia-Eurasia plate boundary: How pre-rift salt controls the modes of continental rifting and mantle exhumation[END_REF].

The review of the sequence of the main tectono-stratigraphic events presented in section 4.1 (Fig. 12) also sheds light on another possible controlling factor. Indeed, the duration of synrift sequences in smooth-slope basins (~35-45 Myr) is significantly longer than those of the West Iberia and Bay of Biscay margins (~15-20 Myr). Thus, the long lifetime of smoothslope extensional basins could favour the depth-dependent ductile thinning of the lower/middle crust by pure shear at the beginning of the rifting stage and may prevent brittle structures from forming within the upper crust.

Conclusions

We infer the evolution of smooth-slope type basins in the Iberian-Eurasian plate junction from the rifting to the breakup stage. At the beginning of the syn-rift stage, depth-dependent crustal thinning is dominantly controlled by distributed pure shear thinning within the lower/middle crust due to the presence of two decoupling levels: (1) the middle crust, which allows the lower crust to be extracted laterally without disturbing significantly the upper crust, and (2) within pre-rift Triassic salt beds, which act as a décollement between the upper crust and the overlying sedimentary cover. Then simple shear becomes localized along a crustal detachment connecting upward with the Late Triassic décollement layer, inducing shearing in the pre-rift salt. When continental breakup occurs, the basin flanks are affected by brittle deformation while the hyperextended domain undergoes dominantly ductile thinning. The rise of the 300°C to 500°C isotherms in the hyperextended domain, from the syn-rift to the continental breakup stage, implies that the originally crystalline upper continental crust and the overlying pre-rift and syn-rift sedimentary pile are affected by depth-dependent ductile thinning. The deformation style during rifting and continental breakup is mainly controlled by burial that results from the complex interaction between the syn-rift sedimentary sequence and the pre-rift salt beds that indirectly contribute to the burial by preserving from disruption the pre-rift sequence in the basin core.

To summarize, hyperextension in Atlantic-type margins leads to a progressive embrittlement of the continental crust due to progressive extraction of the ductile middle crust (e.g. Pérez-Gussinyé et al., 2001;[START_REF] Reston | The structure, evolution and symmetry of the magma-poor rifted margins of the North and Central Atlantic: A synthesis[END_REF]Sutra et al., 2013;[START_REF] Mohn | Structural and stratigraphic evolution of the Iberia-Newfoundland hyper-extended rifted margin: a quantitative modelling approach[END_REF]. In margins with smooth-slope basins, in contrast, crustal thinning is mostly ductile. The latter is favoured by the lateral extraction of the deep crust and the occurrence of thick sedimentary cover (Asti et al., 2019;[START_REF] Duretz | Numerical modelling of Cretaceous Pyrenean Rifting: The interaction between mantle exhumation and syn-rift salt tectonics[END_REF][START_REF] Lagabrielle | A review of cretaceous smooth-slopes extensional basins along the Iberia-Eurasia plate boundary: How pre-rift salt controls the modes of continental rifting and mantle exhumation[END_REF]. This implies that in the distal domain of smooth-slope margins deformation coupling never occurs, thanks to progressive upward migration of the brittle/ductile transition during rifting. Finally, in the reviewed basins, sedimentary burial coupled to the presence of pre-rift salt and a long-lived rifting sequence allow the continental crust to stretch in a dominantly ductile regime from rifting until breakup. [START_REF] Issautier | Structural inheritance and salt tectonics controlling pseudosymmetric rift formation during Early Cretaceous hyperextension of the Arzacq and Tartas Basins (southwest France)[END_REF]; (B) Arzacq sub-basin [START_REF] Issautier | Structural inheritance and salt tectonics controlling pseudosymmetric rift formation during Early Cretaceous hyperextension of the Arzacq and Tartas Basins (southwest France)[END_REF]; (C) Cameros basin (modified after Casas-Sainz & Gil-Imaz, 1998); (D) Parentis basin [START_REF] Tugend | Formation and deformation of hyperextended rift systems: Insights from rift domain mapping in the Bay of Biscay-Pyrenees[END_REF]; (E) Columbrets basin [START_REF] Etheve | Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)[END_REF]; (F) Mauléon basin (Saspiturry et al., 2019a); (G) Basque-Cantabrian basin [START_REF] Pedrera | Reconstruction of the exhumed mantle across the North Iberian Margin by crustal-scale 3-D gravity inversion and geological cross section[END_REF]; (H) Central North Pyrenean Zone basins [START_REF] Espurt | Crustal-scale balanced cross-section and restorations of the Central Pyrenean belt (Nestes-Cinca transect): Highlighting the structural control of Variscan belt and Permian-Mesozoic rift systems on mountain building[END_REF]; locations in Figure 1

  Finally, these data collectively indicate that the Jurassic to Early Cretaceous metacarbonate cover forming the current Internal Metamorphic Zone corresponds to pre-rift to basal syn-rift sediments located in the deepest part of the former North Pyrenean Zone basin, which was also characterised by a thin continental crust. The WNW-ESE trending Lourdes and Saint-Gaudens positive Bouguer anomalies coincide with the maximum thickness of the Albian syn-rift turbidites (Figs. 9A-B; Casas et al., 1997). Espurt et al. (2019) interpreted the Saint-Gaudens anomaly as a body of allochthonous mantle pushed northward onto the European margin on the North Pyrenean Frontal Thrust. It corresponds to an allochthonous body of subcontinental mantle that was previously exhumed during Early Cretaceous time (Fig. 9B).

  and Columbrets (Figs. 5D & 5E; Etheve et al., 2018) basins. Both basins exhibit an asymmetric outline associated with a very thin crust in their axial regions. This sheds light on the fact that important crustal thinning was partly accommodated by simple shear deformation along the imaged detachments (Fig. 2B; Issautier et al., 2020). In the Arzacq and Cameros basins, detachment faults have not been imaged but only inferred, although both basins evolved with cover gliding and depocenter migration during the syn-rift stage. For instance, the northern thrust edging the Cameros basin has been interpreted as a reactivated syn-rift southward deepening ramp-flat structure corresponding to an extensional detachment (Figs. 5E-F; Omodeo-Salé et al., 2014). Although the Arzacq, Cameros, Parentis and Columbrets basins did not record continental breakup like the North Pyrenean basins, crustal thinning was fairly advanced, developing under warm thermal conditions during the simple shear stage. Indeed, mature mantle exhumation is evidenced by a positive Bouguer anomaly and a current shallow Moho depth in the Parentis (Figs. 4A & 4D; Jammes, 2009) and Columbrets basins (Figs. 5A-D;

Figure. 1 FIGURE 1

 11 Figure.1

Figure. 2 FIGURE 2

 22 Figure.2

Figure. 3 FIGURE 3

 33 Figure.3

Figure. 4 FIGURE 4

 44 Figure.4

Figure. 5 FIGURE 5

 55 Figure.5

Figure. 6 FIGURE 6

 66 Figure.6

Figure. 7 FIGURE 7

 77 Figure.7

Figure. 8 FIGURE 8

 88 Figure.8

Figure. 9 FIGURE 9

 99 Figure.9

Figure. 10 FIGURE 10

 1010 Figure.10

Figure. 11 FIGURE 11

 1111 Figure.11

  . No vertical exaggeration. The large arrow indicates the degree of extension and the rise in peak metamorphic temperatures throughout the basin evolutionary sequence. Coloured circles indicate maximum sediment temperatures during HT/LP metamorphism.

Figure. 12

 12 Figure.12

This work is part of Saspiturry's Ph.D. research conducted as part of the OROGEN project, cofunded by Total S.A., Bureau de Recherches Géologiques et Minières (BRGM), and Institut National de Sciences de l'Univers (INSU). We thank OROGEN project managers Sylvain Calassou (Total), Emmanuel Masini (Total), Olivier Vidal (CNRS, Centre National de la Recherche Scientifique) and Isabelle Thinon (BRGM). We specially thank Basin Research'

data were created or analysed in this study.