Chromium and Titanium isotopic anomalies in Al-rich chondrules from CV chondrites

Abstract

Al-rich chondrules (ARCs) have characteristics of both Mg-rich chondrules and CAIs, and are important materials for elucidating the relationship between chondrules and CAIs. However, since ARCs are a rare constituent of meteorites, there are very few examples of Cr-Ti isotope ratio measurements in previous studies. In this study, we measured the Cr-Ti isotopic ratios of a total of five ARCs found in two types of CV chondrites. The Ti isotopic ratios of ARCs were found to vary significantly and showed large isotopic anomalies, while the Cr isotopic ratios did not show significant anomalies. The influence of CAI mixing on the isotopic composition of ARCs was found to be significant only for Ti, suggesting that materials with Cr-poor compositions of CAIs and materials with NC-like isotopic compositions are related to the formation of ARCs.