Radiation history of Antarctic and non-Antarctic meteorites

Distributions of the radiation ages of Antarctic and non-Antarctic H chondrites are examined. Distributions of the long-lived cosmogenic radionuclides of Al-26 and Mn-53 in 880 Antarctic and non-Antarctic ordinary chondrites are investigated. The average content of Al-26 in non-Antarctic H chondrites was found to be close to that in non-Antarctic L and LL chondrites. It was discovered that the average content of Al-26 in the Antarctic chondrites is 15 + or - 3 percent higher than that in the Antarctic L and LL chondrites. It is inferred that the fall frequency of L and LL chondrites on the earth was approximately constant but that of H chondrites changed and was maximal about n x 10,000 years ago.