Phase relations in the system LiFMgF2 at elevated pressures: Implications for the proposed mixed-oxide zone of the earth's mantle

摘要: Abstract Solvi and liquidi for various LiFMgF2 mixtures have been determined at pressures up to 40 kbar by differential-thermal-analysis in a piston-cylinder high-pressure device. The melting curves of pure LiF MgF2 were also studied the initial slopes (dTm/dP)P = 0 found be 11.2 8.3°C/kbar, respectively. eutectic composition (LiF)0.64(MgF2)0.36 is independent pressure 35 temperature rises approximately 6.3°C per kbar. Initial 11°C/kbar 35°C/kbar are inferred MgO SiO2 (stishovite) respectively, on basis data their structural analogue compounds. observed solid solution other evidence suggest possibility system (Mg,Fe)OSiO2 under mantle conditions which may important consequences elastic properties “mixed-oxide” zone earth's mantle.