[PPS05-P05] Compositional Estimation of the lunar olivine exposures
Keywords:moon, mantle, Mg#
In this study, we tried to estimate Mg# (Mg/(Mg+Fe) in mole per cent) for these olivine-rich spectra to further asses their origin and to discuss Mg# of the lunar material.
About 150 SP reflectance spectra were dentified as having unambiguous olivine-rich absorption features. In this study, we assumed pure olivine composition for all of the identified spectra. We tried to adapt spectral fitting with correlational constraints developed by  (for example, the center wavelengths of three olivine absorptions are coupled as observed in the previous laboratory measurement ). In this new approach, modal abundance of olivine, pyroxene, and plagioclase were estimated with Mg# of olivine and pyroxene. When we compared the results having smaller errors, Mg# of the volcanic origin is much lower than that of the mantle origin. The estimated Mg# range of the volcanic origin is consistent with the sample analyses of the returned lunar basalt samples . Spectra of the possible crustal intrusion origin tend to have greater fitting errors and need more detailed analyses. Therefore, comparing Mg# between the crustal and mantle origin is currently difficult, though crustal origin spectra with lower fitting errors appear to be lower than that of the possible mantel origin.
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