- 1Institute of Earth Surface Dynamics, Faculty of Geosciences and the Environment, University of Lausanne, Lausanne, Switzerland
- 2GFZ Helmholtz Centre for Geosciences, Potsdam, Germany
- 3Institute of Earth and Environmental Sciences, University of Potsdam, Potsdam, Germany
- 4Institute of Geology, Mineralogy, and Geophysics, Ruhr University Bochum, Germany
The impact of Quaternary glaciation on the exhumation of the western European Alps remains unclear due to a lack of geochronological methods that cover the timespan of 103-106 years. In this study, we combine new ultra-low temperature (<100°C) electron spin resonance (ESR) thermochronometry data, from the Rhône valley (Sion and Visp, Switzerland) with existing low-temperature thermochronometry data (apatite fission track and apatite (U-TH-Sm/He)) from the surrounding area to constrain the exhumation history from the late Miocene to the Quaternary. Ten samples collected near the city of Sion give ESR ages ranging from 0.21 to 0.67 Myr and five samples collected near the city of Visp give ESR ages ranging from 0.67 to 2.04 Myr.
We explored different tectono-geomorphic scenarios using a 3D thermo-kinematic model, Pecube, to estimate recent changes in tectonic uplift and relief of the Rhône valley. Although modelling results from Sion and Visp are slightly offset temporally, they both exhibit at least three main stages of exhumation in the last 15 Myr. A phase of rapid exhumation (~1 km/Myr for Sion and 2 km/Myr for Visp) that started around 5.2 Myr for the Sion area and 7.9 Myr for the Visp area, was followed by a second phase of reduced exhumation (< 0.1 km/Myr). The ESR data provides new constraints on relief evolution and supports rapid valley incision of up to 1.5 km at around 0.6 Myr for both sites. This phase of rapid valley deepening is likely associated with glacial carving of the Rhône since the mid-Pleistocene transition.
The timing of the exhumation phases in the late Neogene are consistent with previous studies, whilst the ESR data offers more precise constraint of the latest phase of exhumation (<1 Myr). Our results demonstrate that quartz ESR thermochronometry is a reliable tool for constraining Quaternary landscape dynamics that offers high resolution over sub-Myr timescales.
How to cite: Wen, X., Bernard, M., King, G., Braun, J., Kranz-Bartz, M., and Schmidt, C.: Exhumation of the western European Alps (Switzerland) using ultra-low temperature and classical thermochronometry and numerical modeling (Pecube) , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16579, https://doi.org/10.5194/egusphere-egu25-16579, 2025.
