The iodine-xenon systems of six Allende inclusions (five Eggs and the Pink Angel) appear to have been altered by non-nebular secondary processes. Evidence for this includes temperature-ordered variations in the initial I isotopic composition within several objects (with older apparent I-Xe ages associated with higher extraction temperatures) and the absence of primitive I-Xe ages. The span of apparent ages seen in Allende objects (10 Ma or more) is probably too long to reflect any nebular process, so at least some alteration probably occurred on the parent body. The range in initial 244Pu 238U ratios for the Eggs (3-14 × 10-3) includes the current best estimates of the bulk solar system value (4-7 × 10-3). For Egg 3, the Pu U ratio varies by a factor of two between extractions, probably the result of fractionation of Pu from U among different phases.
ASJC Scopus subject areas
- Geochemistry and Petrology