Determination of lunar bulk composition by integrated study of lunar feldspathic meteorite and Kaguya data

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To determine the mineral abundance of the lunar crust which formed by lunar magma ocean crystallization, we conducted an integrated study of mineralogical and reflectance spectral analyses of feldspathic lunar meteorites, and data analyses of multiband Imager of Kaguya lunar mission on lunar crust exposed on Copernicus crater. These studies showed that olivines in the lunar crust are replaced by low-Ca pyroxenes by secondary heating events. Numerous meteoroid impacts on the lunar crust after the magma ocean crystallization should have heated and melted the olivine-bearing initial crust, causing replacement of the primary olivines by low-Ca pyroxenes. Thus, the secondary heating of the lunar initial crust likely altered an initial abundance of olivine in the primary lunar crust. Further, lower detectability of olivine than low-Ca pyroxene in visible-near infrared reflectance spectra may further bias the real abundance of olivine in the present lunar crust.