Chinese Journal of Polar Research (极地研究) 2013/25:4 PP.342-351
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.
1 Korotev R L. Lunar geochemistry as told by lunar meteorite. Chemie der Erde-Geochemistry, 2005, 65(4): 297-346.
2 Warren P H. A concise compilation of petrologic information on possibly pristine nonmare Moon rocks. American Mineralogist, 1993, 78: 360-376.
3 欧阳自远. 月球科学概论. 北京: 中国宇航出版社, 2005.
4 王道德. 陨石学研究新进展. 自然杂志, 1995, 17(1): 13-17.
5 Korotev R L, Joliff B L, Carpenter P K. Miller range feldsparthic lunar meteorite//Proceedings of the 42nd Lunar and Planetary Science Conference. The woodlands: LPI, 2011, 1999.
6 Zeigler R A, Korotev R L, Jolliff B L. Pairing relationships among feldspathic lunar meteorites from Miller Range, Antarctica//Proceedings of the 43rd Lunar and Planetary Science Conference. The Woodlands: LPI, 2012: 2377.
7 Nishizumi K, Caffee M W. Relationship among six meteorites from Miller Range, Antarctica based on cosmogenic radionuclides//Proceedings of the 44th Lunar and Planetary Science Conference. The woodlands: LPI, 2013: 2715.
8 Shirai N, Ebihara M, Sekimoto S, et al. Geochemistry of lunar highland meteorites MIL090034, 090036 and 090070//Proceedings of the 43rd Lunar and Planetary Science Conference. The Woodlands: LPI, 2012: 2003.
9 Papike J J. Comparative planetary mineralogy: Chemistry of melt-derived pyroxene, feldspar, and olivine//Proceedings of the 29th Lunar and Planetary Science Conference. Houston: LPI, 1998: 1008.
10 王道德, 林杨挺. 南极陨石研究的启示Ⅲ: 南极月球陨石的综述及其演化历史. 南极研究, 1993, 5(2): 1-20.
11 Hsu W B, Zhang A C, Bartoschewitz R, et al. Petrography, mineralogy, and geochemistry of lunar meteorite Sayh al Uhaymir 300. Meteoritics & Planetary Science, 2008, 43(8): 1363-1381.
12 Stoffler D, Knoell H D, Marvin U B, et al. Recommended classification and nomenclature of lunar highland rocks-a committee report//Proceedings of the Conference on the Lunar Highlands Crust. New York and Oxford: Pergamon Press, 1980: 51-70.
13 Chao E C T. Preliminary genetic classification of Apollo 16 breccias. Lunar and Planetary Science Conference, 1973, 4: 129.
14 Basu A, Riegsecker S E. Reliability of calculating average soil composition of apollo landing sites. Workshop on New Views of the Moon: Integrated Remotely Sensed, Geophysical, and Sample Datasets, 1998: 20.
15 张爱铖, 徐伟彪. Dhofar 1180月球陨石的岩相学和矿物化学研究. 岩石学报, 2007, 23(5): 1160-1168.
16 Zhang A C, Hsu W B. A KREEP clast in the lunar meteorite Dhofar 1180. Lunar and Planetary Science, XXXⅧ, 2007: 1108.