Spatial and Temporal Variations in Landscape Evolution: Historic and Longer-Term Sediment Flux through Global Catchments

Abstract

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Combining contemporary and long-term erosion rates to target erosion hot-spots in the Great Barrier Reef, Australia

“…This difference was due to the under-representation of extreme events in the contemporary record (Covault et al, 2013;Kirchner et al, 2001), or elevated long-term erosion rates due to enhanced sediment production in previous glacial cycles (Delunel et al, 2010;Schaller et al, 2001). The studies that calculated contemporary erosion rates significantly higher than long-term TCN derived erosion all attributed the response to land use change (Gellis et al, 2004;Hewawasam et al, 2003;Siame et al, 2011;Vanacker et al, 2014).…”

“…The approach is best applied to the source areas where sediment was generated (e.g. subcatchment) (Covault et al, 2013;Wittmann and von Blanckenburg, 2009;Wittmann et al, 2011). We also acknowledge that channel avulsions have occurred on the lower Burdekin floodplain several times during the Holocene (Fielding et al, 2006).…”

“…A particle density of 2.65 g cm -3 was used for gauged river channel sites to accommodate a mixture of particle sizes typical of river sediments (based on Covault et al, 2013;Hippe et al, 2012;Siame et al, 2011).…”

Environmental signal propagation in sedimentary systems across timescales

“…Annual hillslope erosion rates (in mm/yr or t/ha/yr), 212 sediment loads (t/yr) and yields (t/km 2 /yr) may be used to compare and contrast systems 213 and help evaluate their overall functioning Covault et al, 2013). Loads and yields are commonly 216 measured with stream gauges (e.g., Milliman and Farnsworth, 2011), which can be used 217 to evaluate catchment erosion rates and/or alluvial storage (e.g., Meade et al, 1990; 218…”

The geological significance of cosmogenic nuclides in large lowland river basins

“…Still the integration period of suspended sediment 599 measurements is, compared to the time scale usually covered by the in situ 600 cosmogenic method, relatively short, such that discrepancies related to different 601 integration time scales are expected (Kirchner et al, 2001;Schaller et al, 2001; 602 Dadson et al, 2003;Covault et al, 2013) For many basins, both gauging-derived erosion rates and specific sediment yields 623 decrease with increasing basin area. This relationship can be described with a power 624 law where the exponent globally varies between -0.06 and -0.85 and can even obtain 625 positive values (Syvitski et al, 2005;de Vente et al, 2007).…”