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

为了确定月球岩浆海洋结晶形成的月壳矿物丰度，我们对月球长石陨石进行了矿物学和反射光谱综合研究，并对哥白尼陨石坑暴露的月壳进行了卡古崖多波段成像仪数据分析。这些研究表明，在二次加热事件中，月壳中的橄榄石被低钙辉石所取代。岩浆海洋结晶后，大量流星体撞击月球地壳，加热并熔化了含橄榄石的初始地壳，导致原生橄榄石被低钙辉石取代。因此，月球初始地壳的二次加热可能改变了原始月球地壳中橄榄石的初始丰度。此外，在可见-近红外反射光谱中，橄榄石的可探测性低于低钙辉石，这可能会进一步影响目前月球地壳中橄榄石的真实丰度。

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.