R5: Extraterrestrial materials

[R5P-02] A nugget of platinum group element sulfides found from a Ryugu sample

*Junya Matsuno¹, Akira Miyake², Megumi Matsumoto³, Tomoki Nakamura³, Yoshio Takahashi⁴, Shinya Yamada⁵, Akira Tsuchiyama¹, Satomi Enju⁶, Hisayoshi Yurimoto⁷, Takaaki Noguchi², Ryuji Okazaki⁸, Hikaru Yabuta⁹, Hiroshi Naraoka⁸, Kanako Sakamoto¹⁰, Shogo Tachibana⁴ (1. Ritsumeikan Univ. , 2. Kyoto Univ., 3. Tohoku Univ., 4. Univ. of Tokyo, 5. Rikkyo Univ., 6. Ehime Univ., 7. Hokkaido Univ., 8. Kyusyu Univ., 9. Hiroshima Univ., 10. JAXA/ISAS)

Keywords:Ryugu, Platinum group elements

We found a brightly shining irregularly shaped grain (nugget) in the backscattered electron image (BSE) from a relatively weak water alteration lithology of the Ryugu Grain. The nuggets were mostly composed of a matrix of Ru, Fe, Ir, Ni, and Os sulfides, with dark ~1 µm Cr sulfide inclusions and bright submicron inclusions in the BSE images. The formation process is not well understood, but it is suspected to be formed in a very reductive environment.