Role of inheritance during tectonic inversion of a rift system in basement-involved to salt-decoupled transition: analogue modelling and application to the Pyrenean–Biscay system

Abstract

Abstract. The reactivation of former rift systems and passive margins during tectonic inversion and their incorporation into fold-and-thrust belts result in significant structural differences not only between internal and external domains, but also along-strike. The Basque–Cantabrian and Asturian systems are among the best examples to address the role of along-strike changes in rift inheritance since they show a transition from salt to basement-inherited structures divided by a transition zone separating thick- from thin-skinned structural domains. While both domains have been widely described in the literature, the transfer system separating the two has not been sufficiently investigated due to poor seismic imaging and the lack of large-scale outcrops. This contribution aims to address the linkage between basement-controlled (i.e. thick-skinned) and salt-decoupled (i.e. thin-skinned) domains and to describe how deformation is accommodated in the transitional zone between these domains. An experimental programme based on analogue models has been designed that was inspired by the transition from the thin-skinned Basque–Cantabrian Pyrenees to the east to the thick-skinned Asturian Massif to the west. As observed in nature, experimental results show that oblique structures (at low angle with the shortening direction) form in the transitional domain, and their location depends on the linkage of the active structures occurring in both surrounding thick- and thin-skinned domains at different positions. Nevertheless, their orientation and evolution are controlled by the underlying decoupling horizon (i.e. salt). The deformation in the thick-skinned domain produces significant topography over a narrow deformation area due to the lack of effective decoupling levels. On the contrary, deformation in the thin-skinned domain is more distributed due to decoupling, resulting in a wider deformation area of less topography. As a result, syn-contractional sedimentation occurs mainly in the foreland basin in front of the thick-skinned domain, whereas it is observed in the foreland but also in piggyback basins in the thin-skinned domain.

Impact of Salt Tectonics on Temperatures Distribution Revealed by RSCM Thermometry in the SW Alps (France)

“…In salt-detached accretionary prisms resulting from the inversion of depressed rift-related basins, the onset of topographic uplift may be delayed for several millions of years (Jourdon et al, 2020). Numerous geological studies conducted in Western Europe have highlighted the importance of salt tectonics in the tectono-sedimentary evolution of fold-and-thrust belts including the Betics (Flinch et al, 1996;Berástegui et al, 1998;Flinch and Soto, 2017;Pedrera et al, 2020), the Maestrat Basin (Vergés et al, 2020), the Basque-Cantabrian Basin (Poprawski et al, 2014(Poprawski et al, , 2021Ducoux et al, 2019;Cumberpatch et al, 2021;Roca et al, 2021;Ramos et al, 2022;Miró et al, 2023), the Spanish Pyrenees (McClay et al, 2004;Lopez-Mir et al, 2014;Burrel and Teixell, 2021;Hudec et al, 2021;Gannaway Dalton et al, 2022;Kalifi et al, 2023;Pedrera et al, 2023), the French Pyrenees (Canérot et al, 2005;Ford and Vergés, 2020;Izquierdo-Llavall et al, 2020;Labaume and Teixell, 2020;Motte et al, 2021), the Corbières in southern France (Crémades et al, 2021;Parizot et al, 2023), the Provence fold-and-thrust belt (Bestani et al, 2016;Espurt et al, 2019;Wicker and Ford, 2021), the Austrian Alps (Schorn and Neubauer, 2014;Granado et al, 2019;Strauss et al, 2021) and the external French Alps (Gigot and Haccard, 1970;…”