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| Titel |
Seasonal mass balance of sediment transport along the upper Urumqi River in Tianshan |
| VerfasserIn |
F. Métivier, Y. Liu, J. Gaillardet, B. Ye, P. Meunier, C. Narteau, E. Lajeunesse, T. Han |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250062381
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| Zusammenfassung |
| Measurements were performed during two complete flow seasons on the Urumqi
River, a proglacial mountain stream in the northeastern flank of the Tianshan, an
active mountain range in Central Asia. This survey of flow dynamics and sediment
transport (dissolved, suspended and bed loads), together with a 25-year record of
daily discharge, enables the assessment of secular denudation rates on this high
mountain catchment of Central Asia. Our results show that chemical weathering
accounts for more than one-third of the total denudation rate. Sediment transported as
bed load cannot be neglected in the balance, given that sand and gravel transport
accounts for one third of the solid load of the river. Overall, the mean denudation
rates are low, averaging 46 t à km-2 à yr-1(17–18 m Myr-1). We furthermore
analyse the hydrologic record to show that the long-term sediment budget is not
dominated by extreme and rare events but by the total amount of rainfall or annual
runoff. The rates we obtain are in agreement with rates obtained from the mass
balance reconstruction of the Plio-Quaternary gravely deposits of the foreland but
signicantly lower than the rates recently obtained from cosmogenic dating of the
Kuitun River sands, west of the Urumqi River. We show that the resolution of this
incompatibility may have an important consquence for our understanding of the
interplay between erosion and tectonics in the semi-humid ranges of Central Asia. |
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