CosmoCalc: An Excel add‐in for cosmogenic nuclide calculations

Abstract

As dating methods using Terrestrial Cosmogenic Nuclides (TCN) become more popular, the need arises for a general‐purpose and easy‐to‐use data reduction software. The CosmoCalc Excel add‐in calculates TCN production rate scaling factors (using Lal, Stone, Dunai, and Desilets methods); topographic, snow, and self‐shielding factors; and exposure ages, erosion rates, and burial ages and visualizes the results on banana‐style plots. It uses an internally consistent TCN production equation that is based on the quadruple exponential approach of Granger and Smith (2000). CosmoCalc was designed to be as user‐friendly as possible. Although the user interface is extremely simple, the program is also very flexible, and nearly all default parameter values can be changed. To facilitate the comparison of different scaling factors, a set of converter tools is provided, allowing the user to easily convert cut‐off rigidities to magnetic inclinations, elevations to atmospheric depths, and so forth. Because it is important to use a consistent set of scaling factors for the sample measurements and the production rate calibration sites, CosmoCalc defines the production rates implicitly, as a function of the original TCN concentrations of the calibration site. The program is best suited for 10Be, 26Al, 3He, and 21Ne calculations, although basic functionality for 36Cl and 14C is also provided. CosmoCalc can be downloaded along with a set of test data from http://cosmocalc.googlepages.com.