Planet Size Controls Fe Isotope Fractionation Between Mantle and Core

Academic Article

Abstract

  • As an element ubiquitous in the Solar system, the isotopic composition of iron exhibits rich variations in different planetary reservoirs. Such variations reflect the diverse range of differentiation and evolution processes experienced by their parent bodies. A key in deciphering iron isotope variations among planetary samples is to understand how iron isotopes fractionate during core formation. Here we report new Nuclear Resonant Inelastic X-ray Scattering experiments on silicate glasses of bulk silicate Earth compositions to measure their force constants at high pressures of up to 30¬†GPa. The force constant results are subsequently used to constrain iron isotope fractionation during core formation on terrestrial planets. Using a model that integrates temperature, pressure, core composition, and redox state of the silicate mantle, we show that core formation might lead to an isotopically light mantle for small planetary bodies but a heavy one for Earth-sized terrestrial planets.
  • Authors

    Published In

    Digital Object Identifier (doi)

    Author List

  • Ni P; Shahar A; Badro J; Yang J; Bi W; Zhao J; Hu MY; Alp EE
  • Volume

  • 49
  • Issue

  • 20