ISOTOPICALLY NORMAL ZIRCONIUM IN MURCHISON HIBONITE 13-13 - IMPLICATIONS FOR A LINK BETWEEN THE E-PROCESSES AND R-PROCESSES

The isotopic composition of zirconium has been measured in Murchison h ibonite grain 13-13 by ion microprobe mass spectrometry. Despite the h ighly anomalous Ti isotopic composition (27% excess of Ti-50), there i s no evidence for any significant anomalies in the Zr isotopic abundan ces. This result is contrary to that expected based on a recent findin g of Zr-96 excesses correlated with Ti-50 excesses in Allende refracto ry inclusions from which a link between the nucleosynthetic e- and r-p rocesses was proposed. While Zr and Ti isotopic anomalies may exist to gether in Allende inclusions, it must be demonstrated more definitivel y that the Zr and Ti isotopic anomalies represent a genetic associatio n rather than simply a mix of isotopically anomalous components with d ifferent degrees of dilution by normal solar material. If the Zr-96 ex cess in the Allende inclusions is indeed a signature of the r-process, then the absence of a correlated excess of Ti-50 with Zr-96 in the Mu rchison hibonite indicates that the e- and r-processes are not always associated.