TY - JOUR

T1 - Pervasive aqueous alteration in the early Solar System revealed by potassium isotopic variations in Ryugu samples and carbonaceous chondrites

AU - Hu, Yan

AU - Moynier, Frédéric

AU - Dai, Wei

AU - Paquet, Marine

AU - Yokoyama, Tetsuya

AU - Abe, Yoshinari

AU - Aléon, Jérôme

AU - Alexander, Conel M. O'D.

AU - Amari, Sachiko

AU - Amelin, Yuri

AU - Bajo, Ken-ichi

AU - Bizzarro, Martin

AU - Bouvier, Audrey

AU - Carlson, Richard W.

AU - Chaussidon, Marc

AU - Choi, Byeon-Gak

AU - Dauphas, Nicolas

AU - Davis, Andrew M.

AU - Di Rocco, Tommaso

AU - Fujiya, Wataru

AU - Fukai, Ryota

AU - Gautam, Ikshu

AU - Haba, Makiko K.

AU - Hibiya, Yuki

AU - Hidaka, Hiroshi

AU - Homma, Hisashi

AU - Hoppe, Peter

AU - Huss, Gary R.

AU - Ichida, Kiyohiro

AU - Iizuka, Tsuyoshi

AU - Ireland, Trevor R.

AU - Ishikawa, Akira

AU - Itoh, Shoichi

AU - Kawasaki, Noriyuki

AU - Kita, Noriko T.

AU - Kitajima, Koki

AU - Kleine, Thorsten

AU - Komatani, Shintaro

AU - Krot, Alexander N.

AU - Liu, Ming-Chang

AU - Masuda, Yuki

AU - Morita, Mayu

AU - Motomura, Kazuko

AU - Nakai, Izumi

AU - Nagashima, Kazuhide

AU - Nesvorný, David

AU - Nguyen, Ann

AU - Nittler, Larry

AU - Onose, Morihiko

AU - Pack, Andreas

AU - Park, Changkun

AU - Piani, Laurette

AU - Qin, Liping

AU - Russell, Sara S.

AU - Sakamoto, Naoya

AU - Schönbächler, Maria

AU - Tafla, Lauren

AU - Tang, Haolan

AU - Terada, Kentaro

AU - Terada, Yasuko

AU - Usui, Tomohiro

AU - Wada, Sohei

AU - Wadhwa, Meenakshi

AU - Walker, Richard J.

AU - Yamashita, Katsuyuki

AU - Yin, Qing-Zhu

AU - Yoneda, Shigekazu

AU - Young, Edward D.

AU - Yui, Hiroharu

AU - Zhang, Ai-Cheng

AU - Nakamura, Tomoki

AU - Naraoka, Hiroshi

AU - Noguchi, Takaaki

AU - Okazaki, Ryuji

AU - Sakamoto, Kanako

AU - Yabuta, Hikaru

AU - Abe, Masanao

AU - Miyazaki, Akiko

AU - Nakato, Aiko

AU - Nishimura, Masahiro

AU - Okada, Tatsuaki

AU - Yada, Toru

AU - Yogata, Kasumi

AU - Nakazawa, Satoru

AU - Saiki, Takanao

AU - Tanaka, Satoshi

AU - Terui, Fuyuto

AU - Tsuda, Yuichi

AU - Watanabe, Sei-ichiro

AU - Yoshikawa, Makoto

AU - Tachibana, Shogo

AU - Yurimoto, Hisayoshi

N1 - Publisher Copyright: © 2023 Elsevier Inc.

PY - 2024

Y1 - 2024

N2 - C-type asteroids are the presumed home to carbonaceous chondrites, some of which contain abundant life-forming volatiles and organics. For the first time, samples from a C-type asteroid (162173 Ryugu) were successfully returned to Earth by JAXA's Hayabusa2 mission. These pristine samples, uncontaminated by the terrestrial environment, allow a direct comparison with carbonaceous chondrites. This study reports the stable K isotopic compositions (expressed as δ41K) of Ryugu samples and seven carbonaceous chondrites to constrain the origin of K isotopic variations in the early Solar System. Three aliquots of Ryugu particles collected at two touchdown sites have identical δ41K values, averaged at −0.194 ± 0.038‰ (2SD). The K isotopic composition of Ryugu falls within the range of δ41K values measured on representative CI chondrites, and together, they define an average δ41K value of −0.185 ± 0.078‰ (2SE), which provides the current best estimate of the K isotopic composition of the bulk Solar System. Samples of CI chondrites with δ41K values that deviate from this range likely reflect terrestrial contaminations or compositional heterogeneities at sampled sizes. In addition to CI chondrites, substantial K isotopic variability is observed in other carbonaceous chondrites and within individual chondritic groups, with δ41K values inversely correlated with K abundances in many cases. These observations indicate widespread fluid activity occurred in chondrite parent bodies, which significantly altered the original K abundances and isotopic compositions of chondrules and matrices established at their accretion.

AB - C-type asteroids are the presumed home to carbonaceous chondrites, some of which contain abundant life-forming volatiles and organics. For the first time, samples from a C-type asteroid (162173 Ryugu) were successfully returned to Earth by JAXA's Hayabusa2 mission. These pristine samples, uncontaminated by the terrestrial environment, allow a direct comparison with carbonaceous chondrites. This study reports the stable K isotopic compositions (expressed as δ41K) of Ryugu samples and seven carbonaceous chondrites to constrain the origin of K isotopic variations in the early Solar System. Three aliquots of Ryugu particles collected at two touchdown sites have identical δ41K values, averaged at −0.194 ± 0.038‰ (2SD). The K isotopic composition of Ryugu falls within the range of δ41K values measured on representative CI chondrites, and together, they define an average δ41K value of −0.185 ± 0.078‰ (2SE), which provides the current best estimate of the K isotopic composition of the bulk Solar System. Samples of CI chondrites with δ41K values that deviate from this range likely reflect terrestrial contaminations or compositional heterogeneities at sampled sizes. In addition to CI chondrites, substantial K isotopic variability is observed in other carbonaceous chondrites and within individual chondritic groups, with δ41K values inversely correlated with K abundances in many cases. These observations indicate widespread fluid activity occurred in chondrite parent bodies, which significantly altered the original K abundances and isotopic compositions of chondrules and matrices established at their accretion.

KW - Aqueous alteration

KW - Asteroid Ryugu

KW - Carbonaceous chondrites

KW - Hayabusa2 mission

KW - Stable potassium isotopes

U2 - 10.1016/j.icarus.2023.115884

DO - 10.1016/j.icarus.2023.115884

M3 - Journal article

AN - SCOPUS:85177786366

VL - 409

JO - Icarus

JF - Icarus

SN - 0019-1035

M1 - 115884

ER -