Exposure history of H5 chondrite Gujargaon
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 690,000/sq cm per Ma 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 Co-60 and high spallogenic Ne-22/Ne-21 ratio of about 1.25. The data on long lived isotopes Be-10, Mn-53, and Al-26 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 Na-22 and Mn-54 are used to estimate the effect of modulation of galactic cosmic rays at the time of solar maximum of 1982. 25 references.
- Research Organization:
- Physical Research Laboratory, Ahmedabad (India)
- OSTI ID:
- 6595159
- Journal Information:
- Meteoritics; (United States), Vol. 23
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
CHONDRITES
CHEMICAL COMPOSITION
ABLATION
ACTIVITY LEVELS
COSMIC RADIATION
HELIUM ISOTOPES
IRRADIATION
ISOTOPE PRODUCTION
NEON ISOTOPES
PARTICLE TRACKS
RADIOISOTOPES
SIZE
IONIZING RADIATIONS
ISOTOPES
METEORITES
RADIATIONS
STONE METEORITES
640101* - Astrophysics & Cosmology- Cosmic Radiation