INTEGRATING NEAR-INFRARED DERIVED MINERALOGY AND GAMMA RAY DERIVED CHEMISTRY OF THE MOON: PROBING IGNEOUS SOURCES FROM ORBIT

Recent data from the Moon Mineralogy Mapper (M³) coupled with elemental data from Lunar Prospector’s Gamma Ray Spectrometer (GRS) provide an opportunity to probe the composition of the lunar surface in great detail. Hyperspectral near-infrared data measure diagnostic mafic absorption bands, which can be used to infer the mineral composition, structure, and in some cases even site occupancy for iron-bearing minerals. They are also sensitive to vibrational absorptions produced by hydroxyl and water bound within or adsorbed to a mineral. Recent studies of lunar water have primarily focused on production of hydroxyl (and/or water) through interactions of the solar wind with lunar soil, but new evidence suggests that some of the hydroxyl observed from orbit may be magmatic water, bound within the minerals themselves. In the case of Bullialdus crater, this hydroxyl is found in association with noritic mineralogy, and also coincides with an enhancement in thorium as detected by the Lunar Prospector. This suggests that the rocks within Bullialdus crater also contain a large amount of potassium, rare earth elements, and phosphorus (KREEP). We present new data comparing the relative hydroxyl content of prominent noritic exposures and their association with Lunar Prospector thorium for additional locations on the Moon.