Crystallization of Lunar Basaltic Meteorites Northwest Africa 032 and 479: Preservation of the Parent Melt Composition and Relationship to Lap

Introduction: Only 5 meteorites were classified into unbrecciated lunar mare basalt so far, although there are about 40 lunar meteorites known to date. NWA 032 and its paired meteorite NWA 479 (NWA) are such crystalline mare basalts, and show a porphy-ritic texture composed of euhedral olivine and pyrox-ene grains with dendritic mesostasis of pyroxene, pla-gioclase and accessory minerals (ilmenite, chromite, ulvöspinel and fayalite) (Fig. 1). Olivine grain is chemically zoned from the Fo 66 core to the Fo 48 rim. Pyroxene is also zoned from pigeonite (En 59 Fs 31 Wo 10) to Fe-rich pyroxene rim via augite mantle (En 37 Fs 24 Wo 39). This meteorite is similar to Apollo 12 ilmenite basalt in major element chemistry although REE patterns between these samples are different [1]. In this abstract we report results of MELTS calculation and ongoing crystallization experiments to investigate the formation history of NWA. We also compare the results of this study to that of LAP 02205 [2], which is the fifth and newest crystalline lunar mare basalt having many mineralogical similarities to NWA. MELTS calculation: We calculated the liquidus temperature and phase assemblages from the bulk composition of NWA with MELTS program [3]. According to the calculation results, the liquidus temperature is 1192