[P-PS07] Planetary Sciences

[PPS07-P11] Consideration of C-type asteroid fragmentation events using U-Pb dating of heated CM chondrite NWA11024

*Yuto Uehara¹, Kentaro Terada¹, Kohei Fukuda¹, Naoto Takahata², Yuji Sano³, Mathis Ludwig¹ (1.Department of Earth and Space Science, Graduate School of Science, Osaka University, 2.Atmosphere and Ocean Research Institute, the University of Tokyo, 3.Center for Advanced Marine Core Research, Kochi University)

Keywords:carbonaceous chondrite, thermal metamorphism, U-Pb dating

Both the existence of asteroid families such as Polana/Eulalia and the rubble pile structures of 162173 Ryugu and 101955 Bennu are absolute evidence that that large parent bodies of C-type asteroids (>100 km in diameter) have been disrupted into smaller pieces by catastrophic collisions. However, unlike ordinary meteorites related to S-type asteroids, the impact history of carbonaceous chondrite has not been well understood (Amsellen et al. 2020).
In this study, we investigated a U-Pb systematics of apatites in the heated CM chondrite NWA 11024, which had experienced a thermal metamorphism of 400-600 °C (Ebert et al. 2019), using the NanoSIMS. Two U decay series (²³⁸U-²⁰⁶Pb and ²³⁵U-²⁰⁷Pb) provided chronological information of not only a crystallization age but also an alteration age. At the conference, we will discuss the obtained ages and its heat sources.


Amsellem E. et al. (2020) Icarus 339, 113593.
Ebert S. et al. (2019) Meteoritics & Planetary Science 54, 328-356.