CHLORINE 36 AND ARGON 39 IN METEORITES AND THE EXPOSURE AND TERRESTRIAL AGES OF IRON METEORITES
About 30 meteorites were analyzed. The decay rates of chlorine-36 varied between 0 and 28 dpm/kg; for argon-39, between 0 and 23 dpm/kg. Together with the argon-36 content, cosmic ray exposure ages were calculated for the meteorites analyzed. As already previously suspected, all the octihedrites, and mainly the medium octahedrites, show exposure ages of about 500 million years. Very large differences in the cosmic ray exposure ages were observed for the group of the hexahedrites. Problems about the orbits of the hexahedrites are discussed and special boundaries for their orbits were deduced from the measurements. It could be shown that the mean cosmic ray irtensity during the last 300 years was the same as during the last 300,000 years. Argon-39 was looked for in 21 different iron meteorites which were finds, and all of them, except Keen Mountain, showed no argon-39 activity. Lower limits for the terrestrial age between 1000 to 2000 years were calculated for these finds. For Keen Mountain meteorite the terrestrial age came out as about 1300 years. One meteorite, namely Tamarugal, showed also no chlorine-38 activity, indicating a terrestrial age of more than 1.5 million years. For Clark County meteorite, a terrestrial age of 600,000 years was calculated. (auth)
- Research Organization:
- Max-Planck-Institut fur Chemie, Mainz
- NSA Number:
- NSA-17-040988
- OSTI ID:
- 4632046
- Report Number(s):
- AFCRL-62-1092; AD-292913
- Country of Publication:
- United States
- Language:
- English
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