  Because of the high energies involved, giant impacts that occur during
planetary accretion cause large degrees of melting. The depth of melting in the
target body after each collision determines the pressure and temperature
conditions of metal-silicate equilibration and thus geochemical fractionation
that results from core-mantle differentiation. The accretional collisions
involved in forming the terrestrial planets of the inner Solar System have been
calculated by previous studies using N-body accretion simulations. Here we use
the output from such simulations to determine the volumes of melt produced and
thus the pressure and temperature conditions of metal-silicate equilibration,
after each impact, as Earth-like planets accrete. For these calculations a
parametrised melting model is used that takes impact velocity, impact angle and
the respective masses of the impacting bodies into account. The evolution of
metal-silicate equilibration pressures (as defined by evolving magma ocean
depths) during Earth's accretion depends strongly on the lifetime of
impact-generated magma oceans compared to the time interval between large
impacts. In addition, such results depend on starting parameters in the N-body
simulations, such as the number and initial mass of embryos. Thus, there is the
potential for combining the results, such as those presented here, with
multistage core formation models to better constrain the accretional history of
the Earth.
