Calcium Isotopic Anomalies in the Allende Meteorite

We report isotopic anomalies inCa which were found in two Ca-Al-rich inclusions of the Allende meteorite. These inclusions previously had been shown to contain special anomalies for Mg and 0 which were attributed to fractionation and unknown nuclear effects. The Ca data when corrected for mass fractionation by using 4°Ca; 44Ca as a standard show nonlinear isotopic ~ffects in 48Ca of + 13.5 per mil ~nd in 42Ca of ~ 1. 7 per mil for one sample: The second sample shows a 48Ca depletion of 2.~ per mil, but all other Isotopes are normal. Samples with large excesses in 26Mg show no Ca anomahes,. The effects demonstr.ate that isotopic anomalies exist for higher-atomic-number refractory elements m ~olar-system matenals and do not appear to be readily explainable by a simple model. rr:he ~orrelation of 0, Mg, and Ca results on the same inclusions requires the addition and preservatiOn m the solar system of components from diverse nucleosynthetic sources. Observed anomalous _M.g. an~ Ca c?mpositions ~or cot;xi~ting n;inera~ phases are uniform within each inclusion, and require ~mtral. Isotopic ho?logeneitY. withm an I.nclusi.on but the preservation of wide variations between mclusions .. A?sun;mg. form~tron of these. mcluswns by condensation from a gaseous part of the solar nebula, this Imphes Isotopic heterogeneity on a scale of 10--102 km within the nebula. Subject headings: meteors and meteoritesnucleosynthesisstars: supernovae