Abstract
Abstract. The rate at which low-lying sandy areas in temperate regions, such as the Campine Plateau (NE Belgium), have been eroding during the Quaternary is a matter of debate. Current knowledge on the average pace of landscape evolution in the Campine area is largely based on geological inferences and modern analogies. We performed a Bayesian inversion of an in situ-produced 10Be concentration depth profile to infer the average long-term erosion rate together with two other parameters: the surface exposure age and the inherited 10Be concentration. Compared to the latest advances in probabilistic inversion of cosmogenic radionuclide (CRN) data, our approach has the following two innovative components: it (1) uses Markov chain Monte Carlo (MCMC) sampling and (2) accounts (under certain assumptions) for the contribution of model errors to posterior uncertainty. To investigate to what extent our approach differs from the state of the art in practice, a comparison against the Bayesian inversion method implemented in the CRONUScalc program is made. Both approaches identify similar maximum a posteriori (MAP) parameter values, but posterior parameter and predictive uncertainty derived using the method taken in CRONUScalc is moderately underestimated. A simple way for producing more consistent uncertainty estimates with the CRONUScalc-like method in the presence of model errors is therefore suggested. Our inferred erosion rate of 39 ± 8. 9 mm kyr−1 (1σ) is relatively large in comparison with landforms that erode under comparable (paleo-)climates elsewhere in the world. We evaluate this value in the light of the erodibility of the substrate and sudden base level lowering during the Middle Pleistocene. A denser sampling scheme of a two-nuclide concentration depth profile would allow for better inferred erosion rate resolution, and including more uncertain parameters in the MCMC inversion.
Highlights
The Campine area is a sandy region which covers part of northeastern Belgium and the southern Netherlands (Fig. 1)
There is a clear decrease in 10Be concentration with depth, except for two samples (MHR-If the previous condition (II)-04 and MHR-II-06) which contain higher cosmogenic radionuclide (CRN) concentrations (Table 1 and Fig. 6)
It is striking that the CRN concentrations are consistently higher for the two samples where the finer (250–500 μm) grain size fraction was analyzed
Summary
The Campine area is a sandy region which covers part of northeastern Belgium and the southern Netherlands (Fig. 1). It is part of the European sand belt and is drained by rivers that belong to the Scheldt Basin. The Campine area roughly coincides with the geological Campine Basin, the southeastern part of the North Sea basin. From a geodynamic point of view, the Campine Basin is located in an intermediate position in between the rapidly subsiding Roer Valley graben in the north, and the uplifting Brabant and Ardennes massifs in the south (Fig. 2). The Campine Basin has a long Cenozoic burial history.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
