R5: Extraterrestrial materials

[R5-08] Magnetite 3D morphology in Hayabusa2 returned sample: diversity and implication

*Akira Tsuchiyajma¹, Megumi Matsumoto², Junya Matsuno¹, Akira Miyake³, Tomoki Nakamura², Takaaki Noguchi³, Masanori Yasutake⁴, Kentaro Uesugi⁴, Akihisa Takeuchi⁴, Satomi Enju⁵, Aki Takigawa⁷, Shota Okumura³, Itaru Mitsukawa³, Mingqi Sun⁶, Yuma Enokido² (1. Ritsumeikan Univ. , 2. Tohoku Univ. Sci., 3. KyotoUniv. Sci., 4. JASRI/SPring8, 5. Ehime Univ. Sci., 6. CAS/GIG, 7. Tokyo Univ. Sci.)

Keywords:Asteroid Ruygu, X-ray nanotomography, TEM, aqueous alteration, CI chondrite

We performed nanoCT analysis of samples returned from the Asteroid Ryugu by Hayabusa2 and revealed the 3D morphology of magnetite crystals in the samples. Based on this result, we proposed an evolution model for the magnetite morphology during aqueous alteration, where spherulites precipitated followed by plaquette and framboids from highly-supersaturated solution and then finally larger euhedral crystals precipitated from solution of decreased degree supersaturation.