Iron isotope evidence for very rapid accretion and differentiation of the proto-Earth.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32095530.
- Also identified by DOI 10.1126/sciadv.aay7604 and PMC identifier 7015677.
- Licence recorded as CC BY-NC.
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Abstract
Nucleosynthetic isotope variability among solar system objects provides insights into the accretion history of terrestrial planets. We report on the nucleosynthetic Fe isotope composition (μ<sup>54</sup>Fe) of various meteorites and show that the only material matching the terrestrial composition is CI (Ivuna-type) carbonaceous chondrites, which represent the bulk solar system composition. All other meteorites, including carbonaceous, ordinary, and enstatite chondrites, record excesses in μ<sup>54</sup>Fe. This observation is inconsistent with protracted growth of Earth by stochastic collisional accretion, which predicts a μ<sup>54</sup>Fe value reflecting a mixture of the various meteorite parent bodies. Instead, our results suggest a rapid accretion and differentiation of Earth during the ~5-million year disk lifetime, when the volatile-rich CI-like material is accreted to the proto-Sun via the inner disk.