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Exposure History of H5 Chondrite Gujargaon
Author(s) -
Bhandari N.,
Padia J. T.,
Rao M. N.,
Shukla P. N.,
Suthar K. M.,
Sarafin R.,
Herpers U.
Publication year - 1988
Publication title -
meteoritics
Language(s) - English
Resource type - Journals
eISSN - 1945-5100
pISSN - 0026-1114
DOI - 10.1111/j.1945-5100.1988.tb00904.x
Subject(s) - meteoroid , meteorite , isotope , cosmic ray , chondrite , radionuclide , atmosphere (unit) , isotopes of argon , radiochemistry , astrobiology , physics , geology , geochemistry , astrophysics , chemistry , nuclear physics , thermodynamics
— Cosmic ray produced tracks, He and Ne isotopes and radionuclides have been studied in the recently fallen H5 chondrite Gujargaon. The results indicate an exposure age of about 7 Ma. The high track production rates of 0.25 to 0.69 × 10 6 cm −2 Ma −1 suggest that the Gujargaon meteoroid had a small size (R e = 9–10 cm) in space and suffered 1–3 cm ablation in the atmosphere. The conclusion about the meteoroid size is supported by the low activity of neutron capture isotope 60 Co and high spallogenic 22 Ne/ 21 Ne ratio of about 1.25. The data on long lived isotopes 10 Be, 53 Mn and 26 Al are used to derive production rates of these isotopes in a rock having a radius of 9 cm and the activity levels of the short lived isotopes 22 Na and 54 Mn are used to estimate the effect of modulation of galactic cosmic rays at the time of solar maximum of 1982.