title: Early aqueous activity on the ordinary and carbonaceous chondrite parent bodies recorded by fayalite.
abstract: Chronology of aqueous activity on chondrite parent bodies constrains their accretion times and thermal histories. Radiometric (53)Mn-(53)Cr dating has been successfully applied to aqueously formed carbonates in CM carbonaceous chondrites. Owing to the absence of carbonates in ordinary (H, L and LL), and CV and CO carbonaceous chondrites, and the lack of proper standards, there are no reliable ages of aqueous activity on their parent bodies. Here we report the first (53)Mn-(53)Cr ages of aqueously formed fayalite in the L3 chondrite Elephant Moraine 90161 as Myr after calcium-aluminium-rich inclusions (CAIs), the oldest Solar System solids. In addition, measurements using our synthesized fayalite standard show that fayalite in the CV3 chondrite Asuka 881317 and CO3-like chondrite MacAlpine Hills 88107 formed and Myr after CAIs, respectively. Thermal modelling, combined with the inferred conditions (temperature and water/rock ratio) and (53)Mn-(53)Cr ages of aqueous alteration, suggests accretion of the L, CV and CO parent bodies ∼1.8-2.5 Myr after CAIs.
authors.affiliation: 1] Hawai'i Institute of Geophysics and Planetology, University of Hawai'i at Mānoa, Pacific Ocean Science &Technology (POST) Building, 1680 East-West Road, Honolulu, Hawai'i 96822, USA [2] University of Hawai'i NASA Astrobiology Institute, Honolulu, Hawai'i 96822, USA.
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Doyle
authors.affiliation: 1] Hawai'i Institute of Geophysics and Planetology, University of Hawai'i at Mānoa, Pacific Ocean Science &Technology (POST) Building, 1680 East-West Road, Honolulu, Hawai'i 96822, USA [2] University of Hawai'i NASA Astrobiology Institute, Honolulu, Hawai'i 96822, USA.
authors.forename: Kaori
authors.initials: K
authors.lastname: Jogo
authors.affiliation: Hawai'i Institute of Geophysics and Planetology, University of Hawai'i at Mānoa, Pacific Ocean Science &Technology (POST) Building, 1680 East-West Road, Honolulu, Hawai'i 96822, USA.
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Nagashima
authors.affiliation: 1] Hawai'i Institute of Geophysics and Planetology, University of Hawai'i at Mānoa, Pacific Ocean Science &Technology (POST) Building, 1680 East-West Road, Honolulu, Hawai'i 96822, USA [2] University of Hawai'i NASA Astrobiology Institute, Honolulu, Hawai'i 96822, USA.
authors.forename: Alexander N
authors.initials: AN
authors.lastname: Krot
authors.affiliation: Center for Computational Astrophysics, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Wakita
authors.affiliation: Department of the Geophysical Sciences, University of Chicago, 5734 South Ellis Avenue, Chicago, Illinois 60637, USA.
authors.forename: Fred J
authors.initials: FJ
authors.lastname: Ciesla
authors.affiliation: Glenn Seaborg Institute, Lawrence Livermore National Laboratory, L-231, Livermore, California 94551, USA.
authors.forename: Ian D
authors.initials: ID
authors.lastname: Hutcheon