Phase relations of MgSiO3-FeSiO3 system up to 64 GPa and 2300 K using multianvil apparatus with sintered diamond anvils

Publication date: Available online 17 August 2019Source: Physics of the Earth and Planetary InteriorsAuthor(s): Takeshi Arimoto, Tetsuo Irifune, Masayuki Nishi, Yoshinori Tange, Takehiro Kunimoto, Zhaodong LiuAbstractWe have developed techniques to perform precise determinations of phase transition boundaries under the pressure and temperatures corresponding to those of the deep lower mantle, using Kawai-type multianvil apparatus (KMA) with sintered diamond anvils. By optimizing the materials and dimensions of the high-pressure furnace assembly, we achieved stable generation of high temperature to 2300 K, at pressures up to ~64 GPa, which is the highest temperature reported in KMA under such high pressure conditions. Phase relations in the MgSiO3-FeSiO3 system have been studied at pressures from 27 to 64 GPa and temperatures of 1800–2300 K by in situ X-ray diffraction measurements, combined with quench experiments, using synthetic pyroxene samples with chemical compositions of FeSiO3 and (Mg0.4Fe0.6)SiO3 as the starting materials. Our results show that the iron content in MgSiO3 bridgmanite increases almost linearly up to 42 mol% of the FeSiO3 component with increasing pressure in this pressure and temperature range. For higher iron proportions, an assemblage of bridgmanite + magnesiowüstite + stishovite is formed, while the oxide mixture of magnesiowüstite and stishovite is stable for the compositions close to FeSiO3. Our results suggest that bridgimanite w...

Source: Physics of the Earth and Planetary Interiors - August 19, 2019 Category: Physics Source Type: research