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| Titel |
Be2D: A model to understand the distribution of meteoric 10Be in soilscapes |
| VerfasserIn |
Benjamin Campforts, Veerle Vanacker, Jan Vanderborght, Gerard Govers |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250134453
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| Publikation (Nr.) |
 EGU/EGU2016-15182.pdf |
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| Zusammenfassung |
| Cosmogenic nuclides have revolutionised our understanding of earth surface process rates.
They have become one of the standard tools to quantify soil production by weathering, soil
redistribution and erosion. Especially Beryllium-10 has gained much attention due to its long
half-live and propensity to be relatively conservative in the landscape. The latter makes 10Be
an excellent tool to assess denudation rates over the last 1000 to 100 × 103 years, bridging
the anthropogenic and geological time scale. Nevertheless, the mobility of meteoric 10Be in
soil systems makes translation of meteoric 10Be inventories into erosion and deposition rates
difficult. Here we present a coupled soil hillslope model, Be2D, that is applied to synthetic
and real topography to address the following three research questions. (i) What
is the influence of vertical meteoric Be10 mobility, caused by chemical mobility,
clay translocation and bioturbation, on its lateral redistribution over the soilscape,
(ii) How does vertical mobility influence erosion rates and soil residence times
inferred from meteoric 10Be inventories and (iii) To what extent can a tracer with a
half-life of 1.36 Myr be used to distinguish between natural and human-disturbed
soil redistribution rates? The model architecture of Be2D is designed to answer
these research questions. Be2D is a dynamic model including physical processes
such as soil formation, physical weathering, clay migration, bioturbation, creep,
overland flow and tillage erosion. Pathways of meteoric 10Be mobility are simulated
using a two step approach which is updated each timestep. First, advective and
diffusive mobility of meteoric 10Be is simulated within the soil profile and second,
lateral redistribution because of lateral soil fluxes is calculated. The performance and
functionality of the model is demonstrated through a number of synthetic and real model
runs using existing datasets of meteoric 10Be from case-studies in southeastern
US. Brute force optimisation allows reliably parameter constraining, resulting in a
good agreement between simulated and observed meteoric 10Be concentrations and
inventories. Our simulations suggest that meteoric 10Be can be used as a tracer to
unravel human impact on soil fluxes when soils have a high affinity to sorb meteoric
10Be. |
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