Empirical Evidence for Latitude and Altitude Variation of the In Situ Cosmogenic 26Al/10Be Production Ratio

We assess if variations in the situ cosmogenic 26Al/10Be production ratio expected from nuclear physics are consistent with empirical data, knowledge critical for two-isotope studies. do this using 313 samples glacially transported boulders or scoured bedrock presumed simple exposure histories Informal Cosmogenic-nuclide Exposure-age Database (ICE-D) latitudes between 53°S to 70°N and altitudes up 5000 m above sea level. Although there were small systematic differences Al/Be ratios measured different laboratories, these not significant part explained by elevation distribution of analyzed each laboratory. observe a negative correlation (p = 0.0005), predictions based on energy dependence reaction cross-sections spatial variability cosmic-ray spectra. detect an increase increasing latitude, but is only single variate model, we attribute at least some sample bias because lower latitude typically higher elevations (and vice versa). Using 6.75 as globally will results perhaps latitudes. Data reported here support rate scaling that incorporates such changes, LSDn scheme, minimize biases.