Phase relations of a simulated lunar basalt as a function of oxygen fugacity, and their bearing on the petrogenesis of the Apollo 11 basalts

A glass of Apollo 11 basalt composition crystallizing at 1 atm at low ƒ02">ƒƒ02 showed the following crystallization sequence; ferropseudobrookite at 1210°C, olivine at 1200°C, ilmenite and plagioclase at 1140°C, clinopyroxene at 1113°C. Ferropseudobrookite and olivine have a reaction relation to the melt. This sequence agrees with that assumed on textural grounds for some Apollo 11 basalts. It also indicates that the Apollo 11 basalts cannot have been modified by low-pressure fractionation.