Noble gases: a record of the early solar system
"Analyses of the noble gases in samples of iron meteorites are presented which indicate the following: 1. The inclusions of iron meteorites contain noble gases with a wide range of isotopic compositions. 2. The noble gas concentration and isotopic anomalies arc often grossly inhomogeneously distributed within a given inclusion and vary from inclusion to inclusion in a meteorite. 3. Silicate inclusions appear to be the most promising samples for I-Xe and Pu-Xe dating. 4. Graphite and troilite in addition to the silicate inclusion contain significant radiogenic ¹²⁹Xe anomalies. 5. The total I-Xe (and in the case of Toluca silicates total Pu-Xe) formation intervals of most of the iron meteorites studied are approximately equal to the total I-Xe and Pu-Xe formation intervals of chondrites. 6. The absence of radiogenic ¹²⁹Xe in silicate inclusions of the Kodaikanal iron meteorite is consistant with the short Rb-Sr and K-Ar ages of this meteorite. The six points above are interpreted as evidence that iron meteorites were not formed as the molten core of a planetary sized body due to heating and gravitational differentiation of chondritic material. Analyses of stone meteorite data indicate that: 1. The matrix material in addition to the chondrules of stone meteorites are suitable for I-Xe dating. 2. The low temperature data obtained from heating experiments on neutron irradiated meteorites can be used to reconstruct the thermal histories of the stone meteorites. The decay parameters are presented for the following decays: 1. The electron-capture decay of ⁸⁶Rb. 2. The decay of ¹³⁴Cs to ¹³⁴Xe. 3. The double beta-decay of ¹³⁰Te. 4. The xenon and krypton yields from the spontaneous fission of ²⁵²Cf"--Abstract, pages ii-iii.
Missouri University of Science and Technology
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