Beryllium-boron and aluminum-magnesium chronology of calcium-aluminum-richinclusions in CV chondrites

We have made Be-B measurements in six calcium-aluminum-rich inclusions (CAI s) (mostly type B inclusions) from CV chondrites and compared them to Al-Mg measurements. All CAIs show B-10 excesses in melilite that are correlated with Be/B ratios. The initial Be-10/Be-9 ratio inferred from the correlatio n line is 6.2 x 10(-4). In contrast to the Be-B system in melilite, the Al- Mg system in anorthite is disturbed. This is probably due to B diffusion in melilite being slow compared with Mg diffusion in anorthite. This suggests that Be-B chronology may be useful for measuring time differences of high- temperature (melting, condensation, etc.) events in the early solar system.