Exposure age calculator

Here the exposure age calculator used to recalculate exposure ages can be downloaded. The calculator comprises a set of scripts for Octave/Matlab that can be used to calculate 10Be and 26Al exposure ages. The code is mainly based on the CRONUS calculator (Balco et al. 2008) and the LSD production rate scaling (Lifton et al. 2014). In addition to the exposure age calculator (expage.m), there are also scripts for calculating erosion rates (erosion.m), burial durations (burial.m), depth profile exposure ages (depthcalc.m + depthcalcET.m), erosion depth for prior exposure samples (preexpE.m), and for calibration of reference 10Be and 26Al production rates (prodrate.m).

 

Main characteristics of the calculator:

Numerical integration over time of the 10Be/26Al production adjusted for sample thickness, topographic shielding, 10Be/26Al decay, and erosion.
Nuclide-specific LSD spallation and muon production rate scaling based on simulated cosmic ray fluxes (Lifton et al. 2014).
Time-dependent spallation production rate with reference 10Be and 26Al production rates based on global average from calibration studies published 2009-2016.
Time-constant muon production rate parameterization (Borchers et al. 2016; Marrero et al. 2016; Phillips et al. 2016) with f* and σ0 calibrated for the expage calculator based on Beacon Heights (Antarctica) depth profile data.
Adjustment of the time-dependent production rate to the sampling year (assuming a constant production since 2010).
Atmospheric pressure based on sample elevation and ERA-40 re-analysis dataset, Antarctica best-fit interpolation, or given directly.
Attenuation length for calculating the spallation production rate adjustments for sample thickness and erosion rate interpolated from atmospheric pressure and cutoff rigidity (Marrero et al. 2016).
10Be half-life: 1.387 Ma (Chmeleff et al. 2010; Korschinek et al. 2010). 26Al half-life: 0.705 Ma (Nishiizumi 2004).
Standardization of 10Be concentrations to the 07KNSTD standard (Nishiizumi et al. 2007). Standardization of 26Al concentrations to the KNSTD standard (Nishiizumi 2004).


Calculator log: calc-log.txt