Fe-Ni-S melt permeability in olivine: Implications for planetary core formation

[1] A controversial issue in models of planetary core formation concerns whether iron- sulfide melts in contact with silicate minerals at high temperature and pressure form permeable, percolating networks. We address this issue by determining interconnectivity and calculating the permeability of quenched olivine- iron- sulfide partial- melt samples synthesized at high temperature and pressure for a range of melt fractions and two melt compositions using 3D synchrotron radiation computed tomography and lattice- Boltzmann simulations. Permeability ranged from similar to 10(-19) m (2) at the lowest concentration of melt (similar to 1% by volume), to similar to 10(-13) m (2) at higher concentrations (similar to 13% by volume). Permeability as a function of melt fraction is described by a relation of the form k = alpha d (2)phi(n) with a scaling exponent n of 3.6. Our findings, considered a lower bound when compared to larger grained planetesimals, show percolation is a viable mechanism for the migration of FeS melt that may be applicable to models of planetary core formation.