Résumé
The Earth’s surface long-term evolution is controlled by the combination of tectonic, erosion and climate processes. Thermal (-kinematic) modelling approaches based on low-temperature thermochronology are efficient tools to reconstruct the thermal evolution of the crust and tectono-geomorphic histories. The isotherm shape and wavelength are especially controlled by the overlying topography and its evolution; therefore, the upper-crust thermal evolution is influenced by both rock exhumation and topographic changes or fault motion. In this context, constraining the tectono-geomorphological evolution of mountain ranges appears as a major challenge, especially in areas where the exhumation history and topographic evolution are contrasted and difficult to disentangle. We performed 1D thermal (QTQt) and 3D thermo-kinematic (Pecube) modelling along the Têt fault (Eastern Pyrenees) using a dense spatial low-temperature thermochronological dataset. In this area, spatio-temporal variations in Neogene faulting are still unclear and the topographic evolution models are debated. 1D thermal modelling reveals a cooling event (∼10°C/Ma) during the Serravallian-Tortonian (12–9 Ma), related to major topographic changes. The different topographic evolution models proposed for the Eastern Pyrenees have been tested in a 3D thermo-kinematic model, using the same low-temperature dataset. Model outcomes show a significant mid-Neogene extensional tectonic event with kilometric displacement along the Têt fault regardless of the topographic scenario considered. This tectonic activity may have had a non-negligible role on the late-stage relief evolution. This example shows that coupled modelling approaches for quantitative interpretation of low-temperature thermochronology data can be relevant to disentangle geomorphological and tectonic components in the upper-crust thermal evolution.