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

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 approximately 5 cm and 8 to 9 cm below the pre-atmospheric 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 to 2) between the abundances of the nuclei of Z >= 70, Z >= 80 and Z >= 90 in galactic cosmic rays in the solar system is obtained by assuming the group of the longest tracks (720 to 900 μm) to correspond to the region of thorium to uranium. (author)