Mg₂SiO₄-CaAl₂Si₂O₈-SiO₂ Diagram. Ternary phase diagram for melting the system Mg₂SiO₄-CaAl₂Si₂O₈-SiO₂ at 0.1 MPa, and also at 1.0 GPa when you press the "Change Pressure" button. The 0.1 MPa diagram is based on data from Irvine (1975). The 1.0 GPa diagram is based on data from Sen and Presnell (1984). The 2.0 GPa diagram is based on data from Liu and Presnell (1990). Temperature is in degrees Celcius and composition is in weight pecent.

The chemical composition of spinel (MgAl₂O₄) does not plot on this diagram. Nevertheless, some magmas with compositions that plot on this diagram will crystallize spinel when cooled. An interactive version of the ternary Mg₂SiO₄-CaAl₂Si₂O₈-SiO₂ diagram with the spinel field removed for simplicty can be found here. Return to Previous View