Model Calculations for Cosmogenic Nuclides in Meteorites and the Lunar Surface. 1. Long-lived RadionuclidesOPEN ACCESS 

Ingo Leya

MAPS, Version of Record online: 27 February 2026

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“Production rates for the cosmogenic radionuclides 10Be, 14C, 26Al, 36Cl, 41Ca, 53Mn, and 60Fe in a large variety of meteorites, that is, ordinary chondrites (H, L, LL), carbonaceous chondrites, HED meteorites, ureilites, Martian meteorites, and iron meteorites and in the uppermost ~2 m of the lunar surface are modeled. The new model, which covers a wide range of pre-atmospheric radii and shielding conditions, is the first version to fully implement primary and secondary α-particles. Additionally, the new model gives for the first time uncertainties that are calculated using the same type of modeling as the production rates; they are therefore no longer best guesses. A series of tests demonstrate that the assumption of a spherical geometry has only little effect on the modeled production rate, as long as the irradiation is isotropic, and that all types of carbonaceous chondrites can be described using one set of particle spectra, that is, the matrix effect for carbonaceous chondrites is small, as long as neutron capture effects are not considered. The new model describes production rates for almost all cosmogenic radionuclides within the estimated uncertainties, which are in the range of 10%–15%. One exception is 53Mn in iron meteorites, for which the model significantly overestimates some of the experimental data. However, this might also be due to erroneous experimental data. Based on the new model calculations, 14C/10Be-, 36Cl/10Be-, and 41Ca/36Cl-production rate ratios, which are used to determine meteorite terrestrial ages, are systematically studied. The model predictions agree with experimentally found correlations. In addition, the 60Fe/53Mn production rate ratios, which are often used to distinguish interstellar from interplanetary 60Fe, are studied in some detail.”