ABSTRACT: The isotopic abundances of the rare gases in the fines are found to be similar to those previously reported for gas-rich meteorites. Relative to the heavy gases, neon and helium are depleted by factors of 2.5 and 10 respectively. Accurate krypton-krypton ages for rocks 10017, 10047, 10057, and 10071 were obtained covering a range of from 47 to 509 x 10(6) years. Varying relative production rates of the krypton and xenon isotopes in these rocks suggest different irradiation conditions and a complex history for at least some of the rocks.
Science 02/1970; 167(3918):548-50. · 31.20 Impact Factor