Cosmogenic in situ production of radionuclides: Exposure ages and erosion rates

Experimental data for the cosmogenic in situ production of radionuclides and its depth dependence are used for two applications, the determination of exposure ages and of erosion rates. Concentrations of the long-lived radionuclides Be-10, C-14 and Al-26 in, quartz are presented as function of exposure age, depth before exposure and erosion rate after exposure. It is shown that the cosmogenic production before exposure can introduce important corrections to the representation without consideration of pre-exposure production. Depth profiles of Be-10, C-14 and Al-26 in quartz and sulfur, of Cl-36 in K2O, CaCO3, granite and concrete and of Mn-53 in Fe2O3 are given as function of erosion rate. Consequences to determinations of neutron fluences in Hiroshima are discussed. (C) 2000 Elsevier Science B.V. All rights reserved.