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Calculated rates of cosmic ray muon‐produced Ne in subsurface quartz
Author(s) -
FernandezMosquera Daniel,
Hahm Doshik,
Marti Kurt
Publication year - 2010
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2010gl044106
Subject(s) - muon , cosmogenic nuclide , cosmic ray , quartz , geology , erosion , nuclide , latitude , isotope , nuclear physics , physics , geomorphology , geodesy , paleontology
Interactions of cosmic ray secondaries with subsurface rocks produce both stable ( 3 He, 21 Ne, 22 Ne) and radioactive ( 10 Be, 26 Al and 36 Cl) cosmogenic nuclides. As the production rates by muons of 21 Ne and 22 Ne 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 21 Ne is affected mainly by fast muon interactions (P μ f 21 Ne = 0.39 ± 0.15 at g −1 a −1 vs P μ − 21 Ne = 0.12 ± 0.03 at g −1 a −1 sea level‐high latitude). We also infer that the resulting production rate ratio (P 21 Ne/P 10 Be) of 21 Ne and 10 Be 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 P 21 Ne/P 10 Be, specifically for long time scales. However, calibrations are needed and may be carried out on a well documented quartz core.