Oxygen potential of high-magnesium magmas.

The article presents statistical calculations to understand the application of mineral geooxometers of high-magnesium magmas. It estimated the composition of magma for intrusive formations by computer modeling of crystallization differentiation. It informs that spinel appear at the onset of magmatic crystallization together with olivine. It analyzed the experimental database on subliquidus equilibria in the silicate systems to conclude results of experiments with products containing spinel. Several equations related to apply the data on the equilibrium of spinel are also presented.