O01_08

Calculating catchmentwide erosion rates using an existing online calculator

Stübner K¹, Balco G²

¹Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany, ²Berkeley Geochronology Center, Berkeley, USA

The calculation of exposure ages and erosion rates from ¹⁰Be and ²⁶Al concentrations in quartz is widely used in geomorphological and Quaternary geological applications. Existing calculators provide a simple means to compute age or erosion rate in a consistent and reproducible way and without the need to delve deeply into production scaling schemes and palaeomagnetic field models. Catchmentwide erosion rates reflect the production rates of the entire basin, and their calculation requires knowledge of the complete production rate model. A "basin production rate" may be approximated from the basin mean geographic coordinates and mean elevation, but because production varies (approximately) exponentially with elevation this approach generally underestimates the true production. Dedicated programs calculate production rates on the scale of a river catchment and explore, for example, the impact of different scaling schemes, muogenic production models, palaeomagnetic models, or the spatial resolution of topographic data. While these programs compute catchmentwide erosion rates the calculation is independent from the commonly used exposure age and erosion rate calculators, and the results are not directly comparable. Here we introduce a new python-based tool that uses the popular online calculator by G. Balco [http://hess.ess.washington.edu/] to compute the complete production rate model of a river catchment and to determine catchmentwide erosion rates from cosmogenic nuclide data. Our goal is to provide an easy-to-use catchmentwide erosion rate calculator, which is fully integrated with existing exposure age and (in situ) erosion rate calculators for consistent and reproducible evaluation of cosmogenic nuclide data in Quaternary geology.