Breakthroughs in Quaternary Geochronology to fill in a key gap of knowledge in Active Tectonics

involved researchers
years project
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samples collected


The determination of fault slip-rate relies on quantitative characterization of late-Quaternary (1-500 ka) deformation with accurate dating of geomorphological surfaces affected by the fault motion over multiple earthquake cycles. However, large epistemic uncertainties in dating alluvial surfaces with Optically Stimulated Luminescence (OSL) and Terrestrial Cosmogenic Nuclides (TCN) methods severely limit discussions and preclude our ability to understand behavior of active faults.

In this project, we are developing complementary approaches to accurately date late-Quaternary morphological surfaces through an exhaustive, detailed and unique direct comparison of both dating methods, a strategy that would then leads to major improvements in our understanding of the respective physical processes associated to these dating methods. “scientificOrganization.png” summarize the scientific organization of the project.

To better understand the systematics of these dating methods, we are combining both OSL and TCN dating methods on the same geomorphic markers with a high-resolution sampling. This approach has the potential to provide new important insights into the processes affecting alluvial landforms in different climatic setting. We aim to produce major advances in constraining sources for the natural variability of the OSL signal for a better understanding of luminescence characteristics from sediment populations with different light-exposure histories.

We are focusing on two challenging study cases where slip rates of active faults are still in debate due to epistemic uncertainties in dating alluvial surfaces. The results of this pioneering project are offering new perspectives for the large scientific community involved in active tectonics. At the national scale, there is no laboratory providing the possibility to apply both dating methods, and the French Earth Sciences community warrants an improvement and thorough understanding of OSL dating methods. Even at the international scale, only a few institutions host and master both OSL and TCN techniques and CEREGE is a unique opportunity in Quaternary geochronology.


Comparison of quartz OSL ages with cosmogenic 10Be ages and their associated uncertainties (compilation made from data available in Owen et al., 2011; Nissen et al., 2009; Le Dortz et al., 2009, 2011; Viveen et al., 2012; Rizza et al., 2011: Delong et Arnold, 2007; Pederson et al., 2006; Armonstrong et al., 2010). The black dashed line is for a ratio 1:1, the green area is for 10Be age overestimates and the yellow area for OSL age overestimates.