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| Titel |
Long-term cosmogenic 10Be catchment-wide erosion rates in the Kruger National Park |
| VerfasserIn |
Christoph Glotzbach, Alexander Paape, Bastian Reinwarth, Jussi Baade, Jordan Miller, Kate Rowntree |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250109495
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| Publikation (Nr.) |
 EGU/EGU2015-9409.pdf |
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| Zusammenfassung |
| In this study we estimated long-term catchment-wide erosion rates in the central and southern
Kruger National Park with cosmogenic 10Be analyses. Samples were collected in
small catchments (2-100 km2) upstream of dams, which were used to determine
short-term sediment yield rates. 10Be-derived erosion rates vary from 4-15 mm/kyr.
Although there are significant site-specific differences in geomorphic parameters
and precipitation we could not identify a single parameter controlling long-term
erosion.
Geomorphic fieldwork reveals that an unknown fraction of sampled sand-sized channel
sediments derived from partly extensive and up to a few-meters deep gully erosion, which
may lead to an overestimation of 10Be-derived erosion rates. Cosmogenic nuclide production
is rapidly decreasing with depth and consequently the measured 10Be concentration
of stream sediments is a mixture of (i) sand with high 10Be concentration from
colluvial creep or sheet flow from hillslopes and (ii) sand with low 10Be concentration
from gully erosion. To correct erosion rates, we quantify sediments derived from
gullies using a combination of mapping gullies using remote sensing data and field
work and geochemical characterisation of intact hillslopes and gully side walls. |
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