Early differentiation of magmatic iron meteorite parent bodies from Mn–Cr chronometry
Publisher DOI
Abstract
Magmatic iron meteorite groups such as IIAB, IIIAB and IVA, represent the largest sampling of extraterrestrial core material from the earliest accreted distinct planetary bodies in the solar system. Chromium isotope compositions of chromite/daubréelite from seven samples, translated into 53Cr/52Cr model ages, provide robust time information on planetary core formation. These ages are within ∼1.5 Ma after formation of calcium-aluminium-rich inclusions (CAIs) and define the time of metal core formation in the respective parent bodies, assuming metal–silicate separation was an instantaneous event that induced strong chemical fractionation of Mn from the more siderophile Cr. The early core formation ages support accretion and differentiation of the magmatic iron meteorite parent bodies to have occurred prior to the chondrule formation interval. The calibration of Mn–Cr ages with established Hf–W ages of samples from the same magmatic iron meteorite groups constrains the initial ɛ53Cr of the solar system to −0.30 ± 0.05, and thus lower than previously estimated.
Date Issued
2021-12-13
Publication Type
Article
Subject(s)
Language(s)
en
Additional Credits
Journal
Geochemical perspectives letters
Publisher
European Association of Geochemistry
ISSN
2410-339X
Access(Rights)
Unknown