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| Titel |
Dissolved rhenium in river waters: Insight into the chemical weathering of fossil organic carbon? |
| VerfasserIn |
Robert Hilton, Jérôme Gaillardet |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250033802
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| Zusammenfassung |
| The store of carbon in rock as fossil organic matter represents ~15x1021 g, which is almost
400 times the total amount of carbon present in the oceans and atmosphere. Oxidation of
fossil organic carbon (FOC) during chemical weathering returns CO2 that was sequestered
from the atmosphere in the geological past, back into the contemporary carbon cycle. Despite
this recognition, the natural rates of FOC weathering are poorly constrained in the modern
environment, as are the precise controls on its variability. This is primarily due
to the difficultly in tracking the dissolved and gaseous carbon produced during
FOC weathering, where biology and carbonate weathering mask its influence at a
catchment-scale. Here we investigate the use of rhenium (Re) as a tracer of FOC
weathering, focusing on a series of mountain catchments in Taiwan. We present dual
methodology for determining dissolved Re content in river waters by ICP-MS,
using pre-concentration and matrix removal via anion exchange chemistry and
by direct analysis through standard-addition. Precision (2sigma) and accuracy at
the ppt level are found to be better than 7%. In the 16 sampled catchments, the
dissolved Re concentrations span the entire range from the published literature. We
investigate the source of dissolved Re in the catchments using measurements of
bedrocks and river sediments, and the comparative behavior of Re to major dissolved
phases. A preliminary estimate of the Re budget derived from the weathering of
FOC is presented, and the implications for the rates of FOC weathering discussed. |
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