High pressure phase transformation of jadeite and stability of NaAlSiO4 with calcium-ferrite type structure in the lower mantle conditions

Phase transformation of Jadeite clinopyroxene was studied at temperatures of 800 and 2200 °C at pressures between 30–75 GPa in externally electrically heated and internally laser-heated diamond anvil cells. It has been found that Jadeite transforms to the assemblage of NaAlSiO4 (calcium-ferrite type structure) plus stishovite at high pressure and temperatures. Therefore NaAlSiO4 calcium-ferrite is stable at the deep lower mantle pressure and temperature conditions.