Planet Formation Fe-Ni-S melt permeability in olivine: Implications for planetary coreformation J. J. Roberts, J. H. Kinney, J. Siebert, and F. J. Ryerson Abstract: 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 1019 m2 at the lowest concentration of melt (1%
by volume), to 1013 m2 at higher concentrations (13% by volume).
Permeability as a function of melt fraction is described by a relation
of the form k = ad2fn 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. Citation: Roberts, J. J., J. H. Kinney, J. Siebert, and F. J. Ryerson (2007), Fe-Ni-S melt permeability in olivine: Implications for planetary core formation, Geophys. Res. Lett., 34, L14306, doi:10.1029/2007GL030497. |