DIX Planetary Science Seminar

Chronology is essential for reconstructing the timing of the events in the Solar System (SS). The time sequence in the SS is constrained by the long-lived (assumption-free absolute age) and short-lived (high-resolution relative age) radiometric dating of age anchors – SS materials formed rapidly enough that all chronometers record the same time.

Calcium-aluminum-rich inclusions (CAIs) are the first solids formed in the SS and are typically regarded as the age anchor of the starting point of the SS. However, the most widely used absolute Pb-Pb and relative Al-Mg chronometers have revealed significant age discrepancies in the duration of CAIs formation and the time between chondrule and achondrite formation when using CAIs as the age anchor. The origin of these age inconsistencies remains controversial, as it could either point to 26Al heterogeneity or to the fact that the dates do not faithfully reflect the formation time of the early Solar System (ESS) materials.

In this presentation, I will review these discrepancies and the recent efforts in the community towards a unified chronology. Then, I will present my recent work, which combines Pb-Pb and Al-Mg dating on CAIs. The new dataset shows that the Pb-Pb and Al-Mg systems have different robustness to post-formation resetting. Finally, I will discuss the implications of this new evidence to resolve the discrepancies in the ESS chronology.