Evolution of a salt-rich transtensional rifted margin, eastern North Pyrenees, France

Abstract

In this field study we reinterpret the narrow eastern North Pyrenean Zone, France, as an inverted salt-rich transtensional rift system based on identification of halokinetic depositional sequences across rift platform to distal rift margin domains with a cumulative throw of >2.8 km on steep Cretaceous faults. The rift platform records extension on detached rotational faults above Triassic evaporites from Jurassic to Aptian with uplift and erosion during the Albian. Transtensional Aptian–Albian minibasins align along the salt-rich rift margin fault zone. In the Aptian–Albian main rift large en echelon synclinal minibasins developed between salt walls, although Jurassic diapiric evolution is likely. Upper Cretaceous units locally record continuing diapirism. The Boucheville and Bas Agly depocentres, altered by synrift HT metamorphism, form the distal rift domain terminating south against the North Pyrenean Fault. The narrowness of the Pyrenean rift, shape of minibasins, en echelon oblique synclinal depocentres and folds coupled with a discontinuous distribution and intensity of HT metamorphism support a transtensional regime along the Iberia–Europe plate margin during late Early and early Late Cretaceous. In this model, the distal European margin comprises deep faults limiting laterally discontinuous crustal domains and ‘hot’ pull-apart basins with mantle rocks directly beneath sedimentary cover.Supplementary material: A table summarizing the stratigraphy of the NE Pyrenees and an interpreted Google Earth view of the Quillan syncline and minibasin are available at https://doi.org/10.6084/m9.figshare.c.5100036

Evidence of decoupled deformation during Jurassic rifting and Cenozoic inversion phases in the salt-rich Corbières-Languedoc Transfer Zone (Pyreneo-Provençal orogen, France)

“…An increasing volume of work documents the mobilization of Keuper evaporites from early Jurassic and throughout the Alpine cycle in and around western Mediterranean orogenic belts (e.g. Graham et al 2012;Espurt et al 2018Espurt et al , 2019aLabaume & Teixell 2019;Vergès et al 2020;Célini et al 2020;Vergés et al 2020;Ford & Vergés 2021). The Corbières-Languedoc Transfer Zone has long been recognized as an area with significant volumes of Keuper evaporites at surface and at depth (Berger et al, 1982;Berger et al, 1997;Berger et al, 1993;Ellenberger et al, 1987;Lespinasse et al, 1982).…”

“…2a) bears witness to the presence of diapirs that pierced to the surface. Ford et Vergés (2021) have recently documented salt-controlled depocentres, particularly of Early Cretaceous age, in the easternmost North Pyrenean Zone.…”

“…Two different kinematic trends are proposed in the literature, (1) NW-SE oriented, as for previous phases, with pure extension in the NE-SW oriented Corbières-Languedoc area and with the Pyrenean domain active as a transfer zone between Atlantic and Alpine Tethys domain (e.g. Ford et al, 2021). In this case the Corbières-Languedoc area never was a rift transfer zone during the Mesozoic, but was an orthogonal segment to the kinematics of the NW-SE oriented Mesozoic extension (2) The extensional trend could be N-S oriented (e.g.…”

The transition from Pyrenean shortening to Gulf of Lion rifting in Languedoc (South France) – A tectonic-sedimentation analysis

“…The orogenic shortening was accommodated in the upper crust by reactivation of the inherited Cretaceous extensional faults, as thrust faults (Debroas, 1990), while the middle crust and exhumed mantle were subducted beneath the European crust (Teixell et al, 2016(Teixell et al, , 2018. The orogen extended eastwards (Ford and Vergés, 2020), in Corbières (Viallard, 1987;Lamotte et al, 2002), Languedoc (Arthaud and Laurent, 1995) and southern Provence (Lacombe and Jolivet, 2005;Bestani et al, 2015), across the present-day Gulf of Lion Gorini et al, 1994). It was later dismantled in Oligocene time to give way to the Gulf of Lion rifted margin Gorini et al, 1994;Séranne et al, 1995;Mauffret and Gorini, 1996;Mascle and Vially, 1999;Séranne, 1999;Guennoc et al, 2000;Lacombe and Jolivet, 2005).…”

Triassic evaporites: a vast reservoir of brines mobilized successively during rifting and thrusting in the Pyrenees

“…Thus, the last decade emphasised the global geodynamic models of the extension, particularly the rise of the mantle, followed by the Cenozoic compression due to plate movements, and contributed first to putting salt tectonics in the background. Recent works tend, however, to reconsider the role of salt as significant in the local deformation mechanisms at the interfaces between basement rocks and the pile of sedimentary formations in the Mesozoic basins and to propose mixed models (Duretz et al, 2020;Ford and Verges, 2020) as already suggested by Jammes et al (2009). Pre-rift salt controls the Cretaceous smooth-slopes extensional basins and the subsequent continental rifting mode (Lagabrielle et al 2020).…”