Sediment transport dynamics in central Australian low-gradient landscapes quantified with cosmogenic nuclides
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Date
2015-07-26
Journal Title
Journal ISSN
Volume Title
Publisher
Science Council of Japan
Abstract
Erosion and sediment routing are key to understanding landscape evolution. In this regard, low-gradient landscapes have remained effectively unstudied in spite of their vast global extent, whereas steep mountain regions have been the focus of most research efforts. Sediment transport and storage is widely thought to occur on much longer timescales in regions of low relief relative to their steep counterparts. Here we apply in situ-produced cosmogenic nuclides to examine the sediment transport and storage history of a low-gradient catchment (Peake River) in arid central Australia. The catchment covers 27,300 km2 with a total relief of 394 m and a mean slope of 32 ± 29 m/km (mean ± 1σ, calculated from 1 arc-sec SRTM). Previous studies in central Australia have focused mainly upon local measurements of landscape lowering and bedrock erosion; however, to better understand the processes shaping these landscapes, we adopt a source-to-sink approach coupling bedrock and hillslope colluvium measurements of cosmogenic nuclides with basin-wide measurements in fluvial sediment. Variation in concentrations and ratios of 10Be and 26Al in sediment provides insights to residence times and burial history as grains are transmitted through the bedrock-hillslope-stream sediment conveyor. Our preliminary results reveal basin-wide erosion rates ranging from 0.2 to 5.8 m/Myr (weighted mean = 0.41 ± 0.03 m/Myr), which are among the lowest rates ever measured. We discuss the sediment dynamics of flat landscapes, emphasizing the contrast with steeper settings. Copyright © 2015, XIX INQUA Congress LOC
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Keywords
Sediments, Dynamics, Australia, Erosion, Rocks, Mountains
Citation
Struck, M., Jansen, J., Codilean, A., Fujioka, T., Fink, D., & Kotevski, S. (2015). Sediment transport dynamics in central Australian low-gradient landscapes quantified with cosmogenic nuclides. Paper presented at the 19th INQUA Congress "Quaternary perspective on climate change, natural hazards and civilization" at Nagoya Convgress Centre, Nagoya, Japan 26 July 2 August 2015.