Monsoon and earthquake controls on sediment flux in an arid bedrock landscape, Zanskar, India
Zusammenfassung der Projektergebnisse
Our results cast a new light on the causes, controls, and consequences of sediment flux across the western Tibetan Plateau margin in NW India: A pronounced order-of-magnitude increase of denudation rates can be traced across the western Tibetan Plateau margin from both river sand petrology and detrital cosmogenic 10Be concentrations. These postglacial denudation rates consistently remain below those of long-term exhumation, and indicate higher denudation rates in the Pleistocene. In this context, seasonality and aridity may override topography as the key controls on denudation rates along the western Tibetan Plateau margin. Sediment may be liberated, but also retained by damming, through large rock-slope failures that occur also in the drier parts of the Himalaya-Tibet orogen. Recognition of these deposits is far from straightforward, as landslide sedimentology offers confusion potential with glacial and impact-related sediments even at the particle scale. Multiple phases of massive Pleistocene aggradation and incision along the Indus and Zanskar Rivers seem to result from paraglacial instead of monsoonal forcing. In particular, Pleistocene lakes in the western Tibetan Plateau margin are much older and more long-lived than previously thought. An unprecedented quantification of Himalayan valley-fill sediment storage indicates a decisive tectonic trapping control, with the bulk of material being sequestered for up to >10^5 yr upstream of the Himalayan syntaxes, i.e. near or above the Tibetan Plateau margins. This pattern of sediment retention may eventually induce millennial lag times between intramontane and foreland/deep-sea fan sedimentary archives.
Projektbezogene Publikationen (Auswahl)
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2011. Glacial advances constrained by 10Be exposure dating of bedrock landslides, Kyrgyz Tien Shan. Quaternary Research 76, 295–304
Sanhueza-Pino, K., Korup, O., Hetzel, R., Munack, H., Weidinger, J.T., Dunning, S., Ormukov, C., Kubik. P.W.
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2011. Rock type, precipitation, and the steepness of Himalayan threshold hillslopes. In: Gloaguen, R., Ratschbacher, L. [Eds.] Growth and collapse of the Tibetan Plateau. Geological Society of London Special Publications 353, 235–249
Korup, O., Weidinger, J.T.
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2012. Earth's portfolio of extreme sediment transport events. Earth-Science Reviews 112, 115–125
Korup, O.
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2012. Without power? Landslide inventories in the face of climate change. Earth Surface Processes and Landforms 37, 92–99
Korup, O., Görüm, T., Hayakawa, Y.
