The Absolute Chronology and Thermal Processing of Solids in the Solar Protoplanetary Disk

TLDR

Transient heating events that formed CAIs and chondrules are key to the solar protoplanetary disk’s evolution, yet their chronology remains unclear. The authors used U‑corrected Pb‑Pb dating to obtain absolute ages of individual CAIs and chondrules from primitive meteorites. The ages reveal that CAIs formed at 4567.30 ± 0.16 Ma and chondrules formed almost simultaneously, spanning 4567.32 ± 0.42 to 4564.71 ± 0.30 Ma, indicating a ~3‑Ma formation period that matches disk lifetimes and refutes a previously assumed age gap.

Abstract

Transient heating events that formed calcium-aluminum - rich inclusions (CAIs) and chondrules are fundamental processes in the evolution of the solar protoplanetary disk, but their chronology is not understood. Using U-corrected Pb-Pb dating, we determined absolute ages of individual CAIs and chondrules from primitive meteorites. CAIs define a brief formation interval corresponding to an age of 4567.30 ± 0.16 million years (My), whereas chondrule ages range from 4567.32 ± 0.42 to 4564.71 ± 0.30 My. These data refute the long-held view of an age gap between CAIs and chondrules and, instead, indicate that chondrule formation started contemporaneously with CAIs and lasted ~3 My. This time scale is similar to disk lifetimes inferred from astronomical observations, suggesting that the formation of CAIs and chondrules reflects a process intrinsically linked to the secular evolution of accretionary disks.