High-Resolution Electron Spin Resonance dating of single quartz grains: a new approach to an old problem (HR-ESR)

• Applicant: Professorin Dr. Melanie Kranz
• Subject Area: Geology ; Physical Geography
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 576006865

Reconstructing depositional histories within sedimentary systems is vital for gaining profound insights into the intricate relationships between landscape evolution, climate change, and human-environment interactions. The Quaternary period, spanning the last 2.6 million years, has been marked by dramatic climatic fluctuations and pivotal stages in human evolution. Unfortunately, many sedimentary records from this era remain inadequately dated due to the limitations of existing geochronological methods, particularly their inability to accurately cover the extensive Quaternary timescale. Electron spin resonance (ESR) dating of quartz emerges as a powerful solution, capable of determining the time since sediment grains were last exposed to sunlight and, in principle, covering the entire Quaternary period. However, conventional ESR protocols, which rely on multi-grain aliquots, often result in imprecise age estimates due to the heterogeneous nature of the signals. Incomplete bleaching and thermally unstable signals are averaged in bulk measurements, obscuring the critical variability needed for dependable dating. This project seeks to revolutionise ESR into a high-resolution dating tool by developing cutting-edge protocols for measuring ESR signals at the single-grain level. By focusing on individual quartz grains, we aim to conquer the limitations posed by grain averaging and significantly enhance the precision of ESR-based chronologies. Our objectives include optimising single-grain measurement strategies, quantifying the impact of signal heterogeneity, and applying advanced statistical models to identify and exclude unreliable grains. High-sensitivity ESR spectroscopy will be employed to detect subtle signal variations, and our new protocols will be rigorously validated using well-characterised synthetic and natural samples. This method will be applied to key Quaternary sites with independent age control, thereby enriching chronologies within their geomorphological and archaeological contexts. Ultimately, this transformative project will establish ESR as a robust, high-resolution geochronological tool, unlocking new insights into Earth’s environmental history and the timing of human presence in ever-changing landscapes.

• DFG Programme: Research Grants