Long-term averaged abundances of VVH cosmic ray nuclei from studies of olivines from Marjalahti meteorite

Abstract

By using a selective etching technique in olivines from the Marjalahti meteorite, more than 2000 tracks longer than 150 μm have been found to be due to galactic cosmic-ray nuclei of Z > 50. The olivines examined were taken from locations ∼ 5 cm and 8–9 cm below the preatmospheric surfaces of the meteorites, respectively. The data on the track distribution are compared with the known values of the relative abundances of the 50<Z≦92 elements of the solar system. A satisfactory agreement (within a factor of 0.5–2) between the abundances of the nuclei of Z≧70,Z≧90 in galactic cosmic rays and in the solar system is obtained by assuming the group of the longest tracks (720–900 μm) to correspond to the region of thorium to uranium.