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| Titel |
Erosion rates deduced from seasonal mass balance along the upper Urumqi River in Tianshan |
| VerfasserIn |
Y. Liu, F. Métivier, J. Gaillardet, B. Ye, P. Meunier, C. Narteau, E. Lajeunesse, T. Han, L. Malverti |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1869-9510
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| Digitales Dokument |
URL |
| Erschienen |
In: Solid Earth ; 2, no. 2 ; Nr. 2, no. 2 (2011-12-13), S.283-301 |
| Datensatznummer |
250000600
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| Publikation (Nr.) |
 copernicus.org/se-2-283-2011.pdf |
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| Zusammenfassung |
| We report measurements 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 × km−2 × 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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