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| Titel |
Particulate Organic Carbon Age Spectra: An Emerging Picture of Variability Related to Discharge and Basin Type |
| VerfasserIn |
Brad Rosenheim, Valier Galy, Elizabeth Williams, Brian Roberts, Mead Allison |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250082457
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| Zusammenfassung |
| Applying ramped pyrolysis 14C analysis to particulate organic carbon (POC) constrains on
the spectrum of radiocarbon ages in the POC. We summarize a multi-year sampling effort on
both the Mississippi Atchafalaya River System (MARS), in which several different discharge
regimes were sampled, and the Narayani River in Nepal, for application of this novel
technique. The emerging picture from the MARS is one of consistency – discharge plays a
role in age spectrum, as does channel type and influence of marine waters. Some
variability in the MARS is related to flood provenance, however large river systems
such as the MARS are integrative of a range of different lithologies and carbon
sources. Age spectra differ between the MARS and monsoon samples in Narayani
River, where high incision rates erode old carbonaceous rocks more efficiently
during high discharge events. The result of limited sedimentary storage of watershed
primary productivity in the Narayani River watershed is substantially wider age
spectra than those from the integrative MARS system. It is likely that the Narayani
River is less consistent in time than the MARS as contributions of old carbonaceous
material likely are driven largely by discharge regime. All Narayani River samples
analyzed to date are from different monsoon seasons, but low discharge events are not
represented in the dataset. Moving forward, our work will focus on how age spectra
change downstream in small mountainous rivers that drain into integrative systems. |
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