High-pressure experiments and the phase diagram of lower mantle and core constituents

Abstract. The interpretation of seismic data and com-puter modeling requires increased accuracy in relevant material properties in order to improve our knowledge of the structure and dynamics of the Earth’s deep inte-rior. To obtain such properties, a complementary method to classic shock compression experiments and theoretical calculations is the use of laser-heated dia-mond cells, which are now producing accurate data on phase diagrams, equations of state, and melting. Data on one of the most important measurements, the melting temperatures of iron at very high pressure, are now converging. Two other issues linking core properties to those of iron are investigated in the diamond cell: One is the melting point depression of iron in the presence of light elements, and the other is the structure of iron a