What Lunar Meteorites Tell Us about the Lunar Highlands Crust

The first meteorite to be found 1 that was eventually (1984) recognized to have originated from the Moon is Yamato 791197 [1]. The find date, November 20, 1979, was four days after the end of the first Conference on the Lunar Highland Crust [2]. Since then, >75 other lunar meteorites have been found, and these meteorites provide information about the lunar highlands that was not known from studies of the Apollo and Luna samples. 1: Of 50 feldspathic lunar meteorites (>20% Al2O3; Fig. 1), all breccias, the average Mg' (mole % MgO/ [(MgO + FeO] of the nonmetal phases) is significantly greater (66.4 ± 1.5; 95% confidence interval) than that of the FAS (ferroan-anorthositic suite [3]) rocks of the Apollo collection (60.1 ± 2.5; Fig. 1). Mare basalt and glass (low Mg', low Al2O3) occur in many of the “highlands” breccias of Fig. 1, thus the nonmare components of the feldspathic lunar meteorites have even greater Mg'