Subsolidus phase relations in the system MgO-ZnO-SiO_2 at high pressure

The subsolidus phase relations were determined experimentally in the system MgO-ZnO-SiO2 at 1.0 GPa and 1 200°C, by use of the high-pressure apparatus “piston-cylinder”. The results showed characteristics of the phases assemblage different from that in similar ternary systems. It is impossible to form complete Mg2SiO4-Zn2SiO4 olivine and Mg2Si2O6 Zn2Si2O6 pyroxene solid solution. This is controlled by the properties of Zn2+ with an outer layer of electron (Ar)3d10, different from others transition metal ions, like Fe2+, Ni2+, Co2+.