Evolution of protoplanetary disk inferred from Al chronology of individual chondrules

We review the Al ages of chondrules in various type 3.0 chondrites. The Al ages of chondrules are 1–3 Myr after calcium-aluminum-rich inclusion (CAI) for LL3.0, CO3.0, and Acfer 094 (Ungrouped C 3.0). Available data for chondrules in CR chondrites indicate that many chondrules are relatively younger (‡3 Myr), although data from chondrules in CR3.0 are not yet available to confirm their younger ages. The total ranges for the Al ages of chondrules in a single chondrite group are more than 0.5–1 Myr. However, most chondrules show relatively narrow range of ages in a single chondrite group (0.2–0.4 Myr, 1 SD), which might be short enough to preserve the group-specific chemical and isotope signatures against radial diffusion of solid in the disk. Distinct oxygen isotope reservoirs might exist in the protoplanetary disk simultaneously, which could be spatially separated.