Influence of the iron spin crossover in ferropericlase on the lower mantle geotherm

摘要: The iron spin crossover in ferropericlase introduces anomalies its thermodynamics and thermoelastic properties. Here we investigate how these can affect the lower mantle geotherm using properties from ab initio calculations. anomalous effect is examined aggregates consisting of mixtures bridgmanite, ferropericlase, CaSiO3 perovskite, with different Mg/Si ratios varying harzburgitic to perovskitic (Mg/Si∼1.5 0.8). We find that introduced by increase isentropic gradient thus proportionally amount ferropericlase. geotherms be as much ∼ 200K hotter than conventional adiabatic at deep conditions. Aggregate elastic moduli seismic velocities are also sensitive geotherm, which impacts analyses composition.