Isotopic composition of xenon from Ca-poor achondrites

The isotopic composition of xenon extracted from six samples of five Ca-poor achondrites in presented. The data suggest that the principal component in all the samples studied here (except Shallowater) is probably atmospheric xenon, which is simply adsorbed onto the meteorite, presumably during the terrestrial life of the sample. A quite high Xe129/Xe130 ratio is observed in xenon from the Shallowater enstatite achondrite, which contained relatively large amounts of primordial xenon compared to the other Ca-poor achondrites. The large special anomaly is thought to imply a genetic relationship between the enstatite achondrites and enstatite chondrites.