Vy. Litvin et al., The system enstatite-nepheline in experiments at 6.5-13.5 GPa: The importance of Na2Mg2Si2O7 for the melting of nepheline-normative mantle, GEOCHEM INT, 38, 2000, pp. S100-S107
Phase relations were experimentally studied at 6.5 GPa in the system enscat
ite-nepheline, which is a pseudobinary inner section of the system forsteri
te-nepheline-SiO2. Forsterite and jadeite form in the low-temperature subso
lidus region (up to 1500 degreesC). Under high temperature subsolidus condi
tions (up to 1600 degreesC), forsterite reacts with jadeite forming Na2Mg2S
i2O7 (NMS-phase), pyrope, and enstatitc.