Figure 3. Terrace Sections
Quaternary Research (2018), 89, 281–306. Copyright © University of Washington. Published by Cambridge University Press, 2017. doi:10.1017/qua.2017.92 Quantifying episodic erosion and transient storage on the western margin of the Tibetan Plateau, upper Indus River Tara N. Jonella,b*, Lewis A. Owenc, Andrew Carterd, Jean-Luc Schwennigere, Peter D. Cliftb aSchool of Geosciences, University of Louisiana at Lafayette, Lafayette, Louisiana 70504, USA bDepartment of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803, USA cDepartment of Geology, University of Cincinnati, Cincinnati, Ohio 45221, USA dDepartment of Earth and Planetary Sciences, Birkbeck College, London WC1E 7HX, United Kingdom eResearch Laboratory for Archaeology and the History of Art, University of Oxford, Oxford OX1 3QY, United Kingdom (RECEIVED April 13, 2017; ACCEPTED September 27, 2017) Abstract Transient storage and erosion of valley fills, or sediment buffering, is a fundamental but poorly quantified process that may significantly bias fluvial sediment budgets and marine archives used for paleoclimatic and tectonic reconstructions. Prolific sediment buffering is now recognized to occur within the mountainous upper Indus River headwaters and is quantified here for the first time using optically stimulated luminescence dating, petrography, detrital zircon U-Pb geochronology, and morphometric analysis to define the timing, provenance, and volumes of prominent valley fills. This study finds that climatically modulated sediment buffering occurs over 103–104 yr time scales and results in biases in sediment compositions and volumes. Increased sediment storage coincides with strong phases of summer monsoon and winter westerlies precipitation over the late Pleistocene (32–25 ka) and mid-Holocene (~8–6 ka), followed by incision and erosion with monsoon weakening.
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