Recycling of Pleistocene valley fills dominates 125 ka of sediment flux, upper Indus River
Loading...
Date
2016-01-01
Journal Title
Journal ISSN
Volume Title
Publisher
European Geophysical Union
Abstract
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. © Author(s)
Description
Keywords
Recycling, Pleistocene epoch, Valleys, Indus-1, Rivers, Glaciers
Citation
Munack, H., Blöthe, J. H., Fülöp, R-H., Codilean, A. T., Fink, D., & Korup, O. (2016). Recycling of Pleistocene valley fills dominates 125 ka of sediment flux, upper Indus River. European Geosciences Union General Assembly 2016, 17-22 April 2016, Vienna, Austria.