Denudation and Carbonate landscape evolution in the European Alps: a novel approach using electron spin resonance thermochronometry (DenudCarb)

• Applicant: Professorin Dr. Melanie Kranz
• Subject Area: Geology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 567344967

The mechanisms driving denudation rates in carbonate landscapes, particularly during the Quaternary period, remain poorly understood, with the European Alps being a critical region of uncertainty. Significant portions of the Alps are composed of carbonate rocks, but their landscapes and their denudation processes remain highly underexplored. This knowledge gap not only hinders our understanding of erosion and landscape evolution but also has far-reaching implications for global carbon cycling, given that the carbonate rocks store substantial amounts of carbon. Current techniques are often unsuitable for measuring denudation rates in carbonate minerals over timescales of up to 10^6 years, due to limitations in sensitivity or applicability, especially in Alpine carbonate regions. This leaves crucial questions unresolved: what roles do climate, tectonics, and surface processes play in shaping carbonate mountain landscapes? And how do they lead to spatially variable denudation histories? The project seeks to address this gap by employing a novel ultra-low temperature thermochronometer technique based on electron spin resonance (ESR) signals in carbonate minerals. ESR thermochronometry provides an innovative method to fill the temporal and spatial gaps in the study of landscape evolution in carbonate terrains. By focusing on four major valleys in the northern Central Alps (Switzerland) - Rhône, Aare, Reuss, and Rhine - this project will deliver key insights into the timing, magnitude, and spatial variability of surface process rates. It will also explore how climate and tectonics influence the development of carbonate Alpine topography, adding to our understanding of regional landscape dynamics. A proof-of-concept study on calcite samples from the Rhône Valley has demonstrated the potential of carbonate ESR thermochronometry. Multiple ESR signals, each exhibiting different thermal sensitivities, were detected in a single sample. The method offers upper dating limits of 10^6-10^7 years, with low closure temperatures (<70°C), making it capable of constraining cooling rates as low as 10 °C/Myr. This high sensitivity allows for the quantification of very low denudation rates. By combining fieldwork, experimental analyses, and numerical modelling, the DenudCarb project will provide a powerful tool for accurately constraining denudation rates in carbonate regions, both in the European Alps and in carbonate landscapes worldwide. Ultimately, ESR thermochronometry will enhance our understanding of the complex interactions between tectonics, climate, and surface processes over Quaternary timescales. This research will not only shed light on the long-term evolution of carbonate landscapes but also contribute to the broader understanding of how carbonate rock systems influence and are influenced by the global carbon cycle.

• DFG Programme: Research Grants
• International Connection: Switzerland
• Cooperation Partner: Professorin Georgina King, Ph.D.