Strontium isotopic anomalies in the Allende Meteorite

We report Sr isotope anomalies in two Ca‐Al‐rich inclusions (EK1‐4‐1 and Cl) of the Allende meteorite which also contain anomalies in O, Mg, Ca, Ba, Nd and Sm. The Sr effects correspond to 84Sr or 88Sr deficits of 3.2‰ and 0.8‰ or to 86Sr excesses of 1.6‰ and 0.4‰. Although it cannot be ascertained in which isotope the anomalies reside, arguments based on the 87Sr abundance indicate that the anomalies may reside in 84Sr and 86 Sr. The data indicate deficits in the p‐process component (84Sr) up to 3.2‰ or in the r‐process component in Sr (88Sr) of up to 32‰ and are not easily reconcilable with effects in Ba and Nd, which indicate excess r, and in Sm, which indicate excess r and p components. The existence of positive and negative anomalies for many elements requires an isotopically heterogeneous solar system at the time of formation of these inclusions. The use of 87Sr/86Sr as a chronometer in the early solar system requires reevaluation, although the anomalies found in Sr thus far do not show the presence of any obvious artifacts in 87Sr/86Sr.