Petrologic mapping of the Moon using Fe, Mg, and Al abundances

Abstract

A comparison between the abundances of major elements on the Moon determined by Lunar Prospector gamma ray spectrometer and those in returned lunar samples is performed. Lunar Prospector shows higher Mg and Al content and lower Si content in western maria in comparison with the lunar sample collection. Lunar Prospector overestimated the Mg content by about 20%. There are no elemental anomalies at the lunar poles: this is additional evidence for the presence of polar lunar hydrogen. Using Mg, Fe, and Al abundances, petrologic maps containing information about the abundances of ferroan anorthosites, mare basalts, and Mg-rich rocks are derived. This approach is useful for searching for cryptomaria and Mg-rich rocks deposits on the lunar surface. A search is implemented for rare rock types (dunites and pyroclastic deposits). Ca-rich, Al-low small-area anomalies are detected in the far side highlands.