Terrestrial, meteoritic, and lunar titanium isotopic ratios revaluated

Abstract

Variations in the titanium isotopic ratios of various solar system materials have been reported by three laboratories. In this work we compare these data (including some new Allende inclusion values reported here) on a common basis. The data of all three groups for terrestrial samples have been found to be consistent within about ten parts per ten thousand for all ratios. The considerable disagreement in reported titanium isotopic anomalies for Allende materials has been investigated by renormalization of all published high-precision titanium isotopic ratio data to various bases in order to assess the nature, number, and loci of possible anomalies. On this basis, variations appear to be present in 46Ti and 47Ti, as well as in 50Ti. All materials reported to date can be divided into two main groups, with the only exceptions being about 10% of Allende inclusions. All but one of the materials reported to date are interpretable as mixtures of a material similar to C-1 and varying amounts (up to about 0.5% of 50Ti) of a material characterized by 50Ti 46Ti{reversed tilde equals}6 and 46Ti ≫ 47Ti + 48Ti + 49Ti. Inclusion EK 1-4-1 requires a further component (up to about 0.5% 46Ti) characterized by 46Ti 47Ti {reversed tilde equals} 1.3 and 47Ti ≫ 48Ti + 49Ti + 50Ti. Show more