Elastic properties of ferropericlase at lower mantle conditions and its relevance to ULVZs

摘要: Abstract The elasticity of Fe x Mg 1 −  O was examined under lowermost mantle temperature and pressure conditions using density functional theory (DFT). addition iron decreases the shear modulus MgO but has varying effects on bulk depending spin state iron. in is dependent also concentration At 136 GPa, low concentrations ( 25 % ) nearly entirely spin, while at very high > 75 it state. There is, as expected, a large decrease seismic velocities with substitution. However, effect greater high-temperatures than low-temperatures, meaning difficult to extrapolate low-temperature experimental results. We cannot simultaneously match ULVZs Fe-enriched ferropericlase. This reflected (dln V s /dln V p T,P , which generally observed be about 3, does not exceed 1.5 for periclase. A mixture ferropericlase ferrous perovskite can cause V up 45%, allows range ULVZ densities matched. find that increases much 3 this value strongly bounds mixing geometry. conclude, therefore, properties readily explained by lower single phase heavily enriched Fe.