  Nucleosynthetic Fe isotopic anomalies in meteorites may be used to
reconstruct the early dynamical evolution of the solar system and to identify
the origin and nature of the material that built planets. Using high-precision
iron isotopic data of 23 iron meteorites from nine major chemical groups we
show that all iron meteorites show the same fundamental dichotomy between
non-carbonaceous (NC) and a carbonaceous (CC) meteorites previously observed
for other elements. The Fe isotopic anomalies are predominantly produced by
variation in 54Fe, where all CC iron meteorites are characterized by an excess
in 54Fe relative to NC iron meteorites. This excess in 54Fe is accompanied by
an excess in 58Ni observed in the same CC meteorite groups. Together, these
overabundances of 54Fe and 58Ni are produced by nuclear statistical equilibrium
either in type Ia supernovae or in the Si/S shell of core-collapse supernovae.
The new Fe isotopic data reveal that Earth's mantle plots on or close to
correlations defined by Fe, Mo, and Ru isotopic anomalies in iron meteorites,
indicating that throughout Earth's accretion, the isotopic composition of its
building blocks did not drastically change. While Earth's mantle has a similar
Fe isotopic composition to CI chondrites, the latter are clearly distinct from
Earth's mantle for other elements (e.g., Cr and Ni) whose delivery to Earth
coincided with Fe. The fact that CI chondrites exhibit large Cr and Ni isotopic
anomalies relative to Earth's mantle, therefore, demonstrates that CI
chondrites are unlikely to have contributed significant Fe to Earth.
