doi:

DOI: 10.3724/SP.J.1084.2013.00342

Chinese Journal of Polar Research (极地研究) 2013/25:4 PP.342-351

PETROGRAPHY AND MINERALOGY OF A NEW LUNAR METEORITE MIL 090036


Abstract:
MIL090036 is a newly found meteorite that belongs to a feldspathic lunar breccia. The detailed petrography and mineralogy of this meteorite are investigated in this paper. It has a typical breccia texture that consists of lithic, mineral and glass clasts. The rock types of the lithic clasts are anorthosite, gabbroic anorthosite, gabbro, regolith breccia, troctolite, microporphyritic crystalline impact melt, and compound clasts. Mineral fragments include pyroxenes, plagioclase, olivine and ilmenite. Glass clasts are mainly plagioclase. The matrix is composed of melt glass, fine-grained recrystallized minerals and mineral clasts. The plagioclase grains (An81-83, An88-93) in gabbro and anorthosite clasts are relatively poorer in Ca than clasts in other breccias (An90-98). Pyroxene grains (Fs12-35 Wo3-44 En22-79) in lithic, mineral and anorthositic melt clasts are relatively poorer in Fe, whereas those in gabbro clasts with melt glass and matrix are relatively enriched in Fe (Fs 37-65Wo10-29 En21-49, Fs18-69 Wo3-45 En14-50). The composition of pyroxene grains in gabbroic anorthosite has a narrow range (Fs24-27 Wo7-14 En59-69). Olivine grains in mineral fragments and matrix have a wider compositional range (Fo57-79) than those in lithic clasts (Fo67-77). Fe/Mn molar ratios of olivine (47 to 83 with an average of 76) and those of pyroxene (76 to 112) fall in the lunar range. The characteristics of texture, mineral assemblage and composition suggest that the MIL090036 meteorite is from an area beyond the sampling range of Apollo and Luna. Further petrographic, mineralogical and compositional studies of MIL090036 will enrich our understanding of the composition and evolution of the Moon's surface.

Key words:lunar meteorite, MIL090036, lunar breccias, petrography, mineralogy

ReleaseDate:2014-07-21 16:59:37



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