Search for p-isotopic anomaly of cerium in the bulk Allende meteorite

Abstract

LREE (La, Ce, Nd and Sm) concentrations, and 143Nd/144Nd and 138Ce/142Ce ratios of two powder aliquots from the bulk Allende meteorite (BAM) were measured to investigate p-isotopic anomalies of Ce. Initial Ce isotope ratios of the two aliquots were calculated assuming an age of 4.56 Ga, identical with ages of other chondrites or eucrites. From the data, we conclude that there are no recognizable p-isotopic anomalies in BAM. This suggests that the existence of p-isotopic anomalies of other REE in BAM is unlikely. Our data can not, however, rule out the possibility that this is only caused by averaging of heterogeneous distribution of p-isotopic anomalies. © 1994, GEOCHEMICAL SOCIETY OF JAPAN. All rights reserved.