The iron isotope composition of enstatite meteorites: Implications for their origin and the metal/sulfide Fe isotopic fractionation factor

Despite their unusual chemical composition, it is often proposed that the enstatite chondrites represent a significant component of Earth's building materials, based on their terrestrial similarity for numerous isotope systems. In order to investigate a possible genetic relationship between the Fe isotope composition of enstatite chondrites and the Earth, we have analyzed 22 samples from different subgroups of the enstatite meteorites, including EH and EL chondrites, aubrites (main group and Shallowater) and the Happy Canyon impact melt. We have also analyzed atite chondrites and achondrites.On average, EH3-5 chondrites (δFethe Fe isotopic compositions of separated (magnetic and non-magnetic) phases from both enst=0.003±0.04‰; 2 standard deviation; n=9; including previous literature data) as well as EL3 chondrites (δFe=0.030±0.038‰; 2SD; n=2) have identical and homogeneous Fe isotopic compositions, indistinguishable from those of the carbonaceous chondrites and average terrestrial peridotite. In contrast, EL6 chondrites display a larger range of isotopic compositions (-0.180‰