ABSTRACT
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Usually, lunar major elements contain Fe, Ti, Mg, Al, Ca, Si, and O. They play very important roles in understanding the origin and evolution of the Moon. It is well known that Si is the essential element in classifying rock types into ultramafic, mafic, intermediate, and felsic rock. Aluminum is commonly used to constrain the origin and evolution of the Moon. For example, the bulk Al content of the Moon can control the point at which plagioclase comes onto the liquidus of the lunar magma ocean (LMO), which in turn affects the timing of primary crust formation (Taylor 1987; Prettyman et al. 2006). Fe and Ti allow us to distinguish among the known types of lunar rocks, and Ti forms the basis for classifying the basalts that make up the lunar maria (Taylor et al. 1991). The abundance and distribution of Mg on the Moon is of interest to many lunar scientists because, in conjunction with mineral data, it can be used to indicate mode of formation (i.e., cumulate vs. lava flow) and in crystallized rock, it indicates the evolution of magma formation.
