Rare earth element identification and quantification in millimetre-sized Ryugu rock fragments from the Hayabusa2 space mission

• Published in: Earth, planets, and space planets, and space, 2022-12, Vol.74 (1), p.146-12, Article 146
• Main Authors: Tack, Pieter, De Pauw, Ella, Tkalcec, Beverley, Lindner, Miles, Bazi, Benjamin, Vekemans, Bart, Brenker, Frank, Di Michiel, Marco, Uesugi, Masayuki, Yurimoto, Hisayoshi, Nakamura, Tomoki, Amano, Kana, Matsumoto, Megumi, Fujioka, Yuri, Enokido, Yuma, Nakashima, Daisuke, Noguchi, Takaaki, Okazaki, Ryuji, Yabuta, Hikaru, Naraoka, Hiroshi, Sakamoto, Kanako, Tachibana, Shogo, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Okada, Tatsuaki, Usui, Tomohiro, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Nakazawa, Satoru, Watanabe, Sei-Ichiro, Tsuda, Yuichi, Vincze, Laszlo
• Format: Article
• Language: English
• Subjects: 7. Planetary science; Apatite; Asteroids; Composition; Computed tomography; Depletion; Dolomite; Earth; Earth and Environmental Science; Earth Sciences; Enrichment; Fluorescence spectroscopy; Fragments; Fundamental parameter quantification; Future Space Missions; Geology; Geophysics/Geodesy; Hayabusa2; Japanese space program; Japanese spacecraft; New Insights in Planetary Science with Hayabusa; Rare earth elements; Rare earth metals; REE; Rocks; Ryugu; Space missions; Testing; Trace elements; X-ray fluorescence; X-ray fluorescence spectroscopy; X-ray spectroscopy
• ISSN: 1343-8832; 1880-5981; 1880-5981
• DOI: 10.1186/s40623-022-01705-3

Millimetre-sized primordial rock fragments originating from asteroid Ryugu were investigated using high energy X-ray fluorescence spectroscopy, providing 2D and 3D elemental distribution and quantitative composition information on the microscopic level. Samples were collected in two phases from two sites on asteroid Ryugu and safely returned to Earth by JAXA’s asteroid explorer Hayabusa2, during which time the collected material was stored and maintained free from terrestrial influences, including exposure to Earth’s atmosphere. Several grains of interest were identified and further characterised to obtain quantitative information on the rare earth element (REE) content within said grains, following a reference-based and computed-tomography-assisted fundamental parameters quantification approach. Several orders of magnitude REE enrichments compared to the mean CI chondrite composition were found within grains that could be identified as apatite phase. Small enrichment of LREE was found for dolomite grains and slight enrichment or depletion for the general matrices within the Ryugu rock fragments A0055 and C0076, respectively. Graphical Abstract