EGU21-289
https://doi.org/10.5194/egusphere-egu21-289
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Un-mixing the effect of post-depositional tillage turbation on OSL age-depth data through measurements and numerical simulations

Marijn van der Meij1, Arnaud Temme2, Mark Verhoeven3, and Tony Reimann1
Marijn van der Meij et al.
  • 1Institute of Geography, University of Cologne, Germany
  • 2Department of Geography, Kansas State University, USA
  • 3Department of Environmental Sciences, Wageningen University and Research, Netherlands

Agricultural systems are subject to severe land degradation, because anthropogenic erosion processes, such as tillage erosion, substantially increase erosion rates compared to natural settings. Optically Stimulated Luminescence (OSL) dating is often used to measure the age of depositional layers to quantify rates of landscape change. OSL dating in agricultural systems is however challenging, because the deposits are reworked in the tillage layer even long after their moment of deposition. This post-depositional mixing resets the built-up luminescence signal, which causes an offset between the apparent OSL ages and the actual deposition ages.

In this study we illustrate the effect of post-depositional mixing on geochronological OSL age-depth data from northeastern Germany and we developed tools to un-mix depositional and post-depositional ages. We analyzed 32 OSL samples from five locations in a kettle hole to reconstruct spatial and temporal deposition patterns. We were able to correct our chronologies for post-depositional mixing by tillage by accounting for (pre-)historical plough regimes. Next to these empirical data, we also modified a Soil-Landscape Evolution Model called Lorica to numerically simulate the effect of post-depositional mixing on depositional ages. This combination of measurements and simulations enabled us to constrain the spatial and temporal effects of post-depositional mixing on OSL age-depth data more accurately. This is an important step towards getting a better grip on the dynamics of agricultural landscapes including the associated dates and rates.

How to cite: van der Meij, M., Temme, A., Verhoeven, M., and Reimann, T.: Un-mixing the effect of post-depositional tillage turbation on OSL age-depth data through measurements and numerical simulations, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-289, https://doi.org/10.5194/egusphere-egu21-289, 2020.

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