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| Titel |
Recycling of Pleistocene valley fills dominates 125 ka of sediment flux, upper Indus River |
| VerfasserIn |
Henry Munack, Jan Henrik Blöthe, Réka-Hajnalka Fülöp, Alexandru T. Codilean, David Fink, Oliver Korup |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250133208
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| Publikation (Nr.) |
 EGU/EGU2016-13792.pdf |
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| Zusammenfassung |
| Rivers draining the semiarid Transhimalayan Ranges along the western Tibetan Plateau
margin underwent alternating phases of massive valley infill and incision in Pleistocene
times. The imprints of these cut-and-fill cycles on long-term sediment fluxes have remained
largely elusive. We investigate the timing and geomorphic consequences of headward incision
of the Zanskar River, which taps the vast More Plains valley fill that currently impedes
drainage of the endorheic high-altitude basins of Tso Kar and Tso Moriri. In situ 10Be
exposure dating and topographic analyses indicate that a phase of valley infill gave way to net
dissection of the >250-m thick sedimentary stacks ∼125 ka ago, i.e. during the last
interglacial (MIS 5e). Rivers eroded >14.7 km3 of sediment from the Zanskar headwaters
since then, fashioning specific sediment yields that surpass 10Be-derived denudation
rates from neighbouring catchments by factors of two to ten. We conclude that
recycling of Pleistocene valley fills has provided Transhimalayan headwater rivers with
more sediment than bedrock denudation, at least since the beginning of the last
glacial cycle. This protracted liberation of sediment stored in thick valley fills could
bias rate estimates of current sediment loads and long-term bedrock denudation. |
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