Water circulation in Ryugu asteroid affected the distribution of nucleosynthetic isotope anomalies in returned sample.
Tetsuya YokoyamaMeenakshi WadhwaTsuyoshi IizukaVinai RaiIkshu GautamYuki HibiyaYuki MasudaMakiko K HabaRyohta FukaiRebekah HinesNicole PhelanYoshinari AbeJérôme AléonConel M O'D AlexanderSachiko AmariYuri AmelinKen-Ichi BajoMartin BizzarroAudrey BouvierRichard W CarlsonMarc ChaussidonByeon-Gak ChoiNicolas DauphasAndrew M DavisTommaso Di RoccoWataru FujiyaHiroshi HidakaHisashi HommaPeter HoppeGary R HussKiyohiro IchidaTrevor R IrelandAkira IshikawaShoichi ItohNoriyuki KawasakiNoriko T KitaKouki KitajimaThorsten KleineShintaro KomataniAlexander N KrotMing-Chang LiuKevin D McKeeganMayu MoritaKazuko MotomuraFrederic MoynierIzumi NakaiKazuhide NagashimaAnn N NguyenLarry R NittlerMorihiko OnoseAndreas PackChangkun ParkLaurette PianiLiping QinSara S RussellNaoya SakamotoMaria SchönbächlerLauren TaflaHaolan TangKentaro TeradaYasuko TeradaTomohiro UsuiSohei WadaRichard J WalkerKatsuyuki YamashitaQing-Zhu YinShigekazu YonedaEdward D YoungHiroharu YuiAi-Cheng ZhangTomoki NakamuraHiroshi NaraokaTakaaki NoguchiRyuji OkazakiKanako SakamotoHikaru YabutaMasanao AbeAkiko MiyazakiAiko NakatoMasahiro NishimuraTatsuaki OkadaToru YadaKasumi YogataSatoru NakazawaTakanao SaikiSatoshi TanakaFuyuto TeruiYuichi TsudaSei'ichiro WatanabeMakoto YoshikawaShogo TachibanaHisayoshi YurimotoPublished in: Science advances (2023)
Studies of material returned from Cb asteroid Ryugu have revealed considerable mineralogical and chemical heterogeneity, stemming primarily from brecciation and aqueous alteration. Isotopic anomalies could have also been affected by delivery of exogenous clasts and aqueous mobilization of soluble elements. Here, we show that isotopic anomalies for mildly soluble Cr are highly variable in Ryugu and CI chondrites, whereas those of Ti are relatively uniform. This variation in Cr isotope ratios is most likely due to physicochemical fractionation between 54 Cr-rich presolar nanoparticles and Cr-bearing secondary minerals at the millimeter-scale in the bulk samples, likely due to extensive aqueous alteration in their parent bodies that occurred [Formula: see text] after Solar System birth. In contrast, Ti isotopes were marginally affected by this process. Our results show that isotopic heterogeneities in asteroids are not all nebular or accretionary in nature but can also reflect element redistribution by water.