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In some cases, information was provided in the original publications; in other cases, we contacted authors directly.Samples in this compilation required recalculation because constraints on production rates, neutron attenuation path length, and the GSA supplemental data item 2011216, reference list for text Figure 1, erosion rate recalculation methods, Arc GIS data extraction methods, statistical methods, results of statistical analyses (including Figs. of Geology, University of Vermont, 180 Colchester Ave., Burlington, Vermont 05405, USA 2 Dept.of Geology and Rubenstein School of the Environment and Natural Resources, University of Vermont, 180 Colchester Ave., Burlington, Vermont 05405, USA ), likely reflecting the acceleration of rock weathering rates under soil.Be erosion rate data (see supplemental data Tables DR1–DR3 [see text footnote 1]). (B) Distribution of outcrop samples and (C) drainage basin samples.Symbols sized to reflect the number of samples per study and colored to indicate relative erosion rate.Parameters considered in the past include latitude, elevation, relief, seismicity, basin slope and area, percent basin cover by vegetation, and mean annual precipitation and temperature.In order to understand the relationship between erosion rates and environmental parameters, we compiled all publicly available outcrop and drainage basin erosion rates inferred from measurements of Be half-life (Nishiizumi et al., 2007), production rate (Balco et al., 2008), and scaling schemes (Lal, 1991) used over the past 24 years, we compared erosion rates and a variety of environmental parameters, both individually and using multivariate statistical methods.
Such an approach presumes that human impact is inconsequential and that short-term measurements of sediment flux are representative of long-term flux rates, but both assumptions have been repeatedly questioned (e.g.
In bedrock outcrops, erosion rates are inferred, assuming erosion occurs steadily through time.
Sampling river sand presumes that stream networks mix and deliver sediment from the entire basin.
The result is a description, at a global scale, of the relationship between these parameters and the erosion rate of both outcrops and drainage basins.
Such relationships are important for understanding the behavior of Earth’s sedimentary system over a variety of spatial and temporal scales as geologists attempt to make sense of human impacts on erosion and sediment generation (Hooke, 1994; Montgomery, 2007; Wilkinson, 2005).
Effective elevation, or the production-rate weighted average elevation for a basin, and effective latitude were determined (see supplemental data methods section [footnote 1]), enabling us to use the CRONUS calculator for determining drainage basin erosion rates.