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| Titel |
Uplift and denudation rates of an actively growing mountain range inferred from in-situ produced cosmogenic 10Be: the Yumu Shan (NE Tibetan Plateau) |
| VerfasserIn |
L. Palumbo, R. Hetzel, T. Minxing, X. Li, J. Guo |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250021362
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| Zusammenfassung |
| Located in the foreland of the Quilian Shan (NE Tibet), the Yumu Shan is an isolated
mountain range bounded by an active NW-SE striking thrust fault. Geomorphic and structural
features such as fault scarps and wind gaps suggest that the ~70 km long range is actively
growing (Hetzel et al., 2004; Tapponnier et al., 1990), hence the tectonic uplift should exceed
the rate of denudation. Here we quantify the rate of these two competing processes using
in-situ produced cosmogenic 10Be. Catchment-wide denudation rates are derived from
10Be concentrations in stream sediments, whereas rock uplift rates are obtained by
combining scarp topographic profiles with dating of geomorphic surfaces deformed by
active thrust faults at the Yumu Shan mountain front. Both denudation and rock
uplift rates integrate over a similar temporal scale (~10-100 ka) and thus over many
earthquake cycles. Our data document that catchment wide-denudation rates vary from
~100 to ~400 mm ka-1 as a function of morphology and lithology, while rock
uplift takes place at the rate of ~0.7 mm ka-1. The difference between these values
confirms that the Yumu Shan is in a topographic pre-steady state and in accordance
with geomorphic and structural features. Tectonic features indicate that over few
millions of years the Yumu Shan may rise to a similar height as the main ranges of the
Qilian Shan farther south, which have peaks with elevations between ~5 and ~5.5
km.
References:
Hetzel R., Tao M., Niedermann S., Strecker M.R., Ivy-Ochs S., Kubik P.W., Gao B. (2004).
Implications of the fault scaling law for the growth of topography: Mountain ranges in the
broken foreland of NE Tibet, Terra Nova, 16, 157–162.
Tapponnier P., Meyer B., Avouac J.P., Peltzer G., Gaudemer Y., Guo S., Xiang H., Yin K.,
Chen Z., Cai S., Dai H. (1990). Active thrusting and folding in the Quilian Shan, and
decoupling between upper crust and mantle in northeastern Tibet, Earth Planet. Sci. Lett., 97,
382-403. |
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