Partial melting of magnesite-bearing peridotites was studied at 6^10 GPa and 1300^17008C. Experiments were performed in a multianvil apparatus using naturalmineralmixes asstartingmaterial placed into olivine containers and sealed in Pt capsules. Partial melts originated within the peridotite layer, migrated outside the olivine container and formed pools of quenched melts along the wall of the Pt capsule. This allowed the analysis of even small melt fractions. Iron loss was not a problem, because the platinum near the olivine container became saturated in Fe as a result of the reaction Fe2SiO4 OlFeFe^Pt alloyþFeSiO3OpxþO2.This reaction led to a gradual increase in oxygen fugacity within the capsules as expressed, for example, in high Fe3þ in garnet. Carbonatitic to kimberlite-like melts were obtained that coexist with olivineþ orthopyroxeneþ garnet clinopyroxenemagnesite depending on P^T conditions.
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Brey et al. (2007) studied this question.