Mgm Deconvolution of Reflectance Spectrum of the Y981031 Lunar Meteorite

Introduction: We report Modified gaussian model (MGM) deconvolution analyses [2] of reflectance spectrum of the Yamato (Y) 981031. Petrological characteristics of Y981031 had already reported [1]. Absorption features derived from the MGM deconvo-lution are compared with the petrological characteristics of Y981031, and implication of the absorption features are discussed. Finally, we propose source region of the meteorite using remote sensing data by future lunar exploration. Method: One polished thin section (PTS) Y981031, 53-6 and one fragment of Y981031, 68 (0.13g) was supplied from National Institute of Polar Research (NIPR). The fragement of Y981031, 68 was crushed in an agate mortar, and then sieve out and collected particles of less than 75 µm for reflectance spectrum measurements. Reflectance spectrum of the powdered sample was measured by a JASCO UV-VIS-NIR reflectance spectrometer at National Space Development Agency of Japan (400-2600 nm in wavelength). Incidence and emission angles are 30 o and 0 o , respectively using Spectralon as reflectance standard. We also repeatedly measured reflectance spectrum of lunar soil 62231 since 62231 reflectance, which was measured at RELAB, was used as reflectance standard soil of Clementine data [3]. Using our 62231 measurements , we derived a correction factor (correction factor = reflectance by RELAB / reflectance our laboratory). The reflectance measurements of Y981031 are corrected using this correction factor to eliminate any differences between two laboratories. Summary of petrology: Y981031 is a polymict regolith breccia, and contains a number of lithic clasts and mineral fragments in a dark comminuted matrix. The mineral fragments are 100 to 500 µm in size, and are composed of major pyroxene, plagioclase and oli-vine including minor iron oxide and Ca-phosphates [1]. The lithic clasts are mainly composed of mafic mare clasts, and some minor highland-origin lithic clasts are observed. The clasts of highland-origin include granu-litic, poikilitic and glassy-matrix breccias. These min-eralogical evidences suggest that Y981031 was derived from extensive mixing area of mafic mare and highland components. Fusion crust glasses are observed on one side of the thinsection. Since chemical compositions of the fusion glass resemble bulk rock compositions of Y981031 [4], the glass chemical com