Calculated rates of cosmic ray muon‐produced Ne in subsurface quartz

[1] Interactions of cosmic ray secondaries with subsurface rocks produce both stable (3He, 21Ne, 22Ne) and radioactive (10Be, 26Al and 36Cl) cosmogenic nuclides. As the production rates by muons of 21Ne and 22Ne in quartz are not known, these can be estimated from published cross sections of analogous reactions, separately for fast and slow muon reactions. Our calculations show that subsurface 21Ne is affected mainly by fast muon interactions (P μf21Ne = 0.39 ± 0.15 at g−1a −1 vs Pμ−21Ne = 0.12 ± 0.03 at g−1a−1 sea level-high latitude). We also infer that the resulting production rate ratio (P21Ne/P10Be) of 21Ne and 10Be changes with depth below the Earth's surface. This ratio in turn may provide supplemental erosion rate information in geological settings of varying erosion surface covers and for long time scales, when radionuclide data provide incomplete information. In environments with very low erosion rates, our calculations indicate noticeable differences in the production ratios P21Ne/P10Be, specifically for long time scales. However, calibrations are needed and may be carried out on a well documented quartz core.