Northwest Africa 482
Purchased: 2001 January 10
Mass: 1015 g
Lunar meteorite (impact melt breccia)
A 1015 g stone was purchased on 2001 January 10 in Alnif, Morocco, by Michael Farmer. The exact location of find is unknown but it is possibly in Algeria. The stone is complete, oriented, and ap-pears relatively unweathered.
Classification and mineralogy (A. Rubin and P. Warren, UCLA, and D. Kring and I. Daubar, UAz): texture is typical of a crystalline impact melt breccia (polymict) with highland affinities; glassy and vesicular melt veins and melt pockets indicate shock subsequent to compaction by an impact event; plagioclase, An95.7Ab4.09Or0.17 (n = 136, UAz); olivine, Fo65-68 (average Fo66) with FeO/MnO = 88 ± 7 g/g (UCLA); olivine Fo68.4 with FeO/MnO = 93.9 ± 7.7 g/g (range: 78.7 to 111) (n = 51, UAz); pyroxene, Fs25Wo17 with nearly uniform Mg/(Mg+Fe) = 67-68 mol% and FeO/MnO = 51 ± 6 g/g (n = 10, UCLA); pyroxene, Wo10.3- 51En32.6-63.9Fs42.6-14.2, mean Mg/(Mg+Fe) = 68 mol%, FeO/MnO = 52 ± 8 g/g (n = 28, UAz); glassy melt veins occur in both UCLA and UAz samples; a 0.1 mm vein (UCLA) has SiO2 = 44.3 wt.%, Na2O = 0.3 wt.%, Al2O3 = 30.0 wt.%, FeO = 3.6 wr.%, MgO = 3.9 wt.%, CaO = 17.3 wt.%, and TiO2 = 0.3 wt.%, which may approximate the bulk meteorite composition.
Specimens: half of the main mass is with Farmer; type specimens, 24 g, UCLA, and 18 g, UAz.
It’s one of the most beautiful lunar meteorites. It’s one of the few crystalline impact-melt breccias. Compositionally, it’s a typical feldspathic lunar meteorite.
Meteoritical Bulletin Database
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Consolmagno G. J., Russell S. S., and Jeffries T. E. (2004) An in-situ study of REE abundances in three anorthositic impact melt lunar highland meteorites. Lunar and Planetary Science XXXV, abstract no. 1370.
Daubar I. J., Kring D. A., Swindle T. D., and Jull A. J. T. (2002) Northwest Africa 482: A crystalline impact-melt breccia from the lunar highlands. Meteoritics & Planetary Science 37, 1797-1814.
Fischer-Gödde M., Becker H., Wombacher F. (2010) Highly siderophile element abundances and 187Os/188Os in lunar impact melt rocks: Implications for late accretion processes in the Earth-Moon system meteorites. 41st Lunar and Planetary Science Conference, abstract no. 2262.
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Joy K. H., Burgess R., Ruzie L, and Clay P. L. (2014) Composition, age and regolith history of feldspathic lunar meteorites. 77th Annual Meeting of the Meteoritical Society, abstract no. 5345.
Korotev R. L. (2005) Lunar geochemistry as told by lunar meteorites. Chemie der Erde 65, 297-346.
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Korotev R. L., Irving A. J., and Bunch T. E. (2008) Keeping up with the lunar meteorites – 2008. Lunar and Planetary Science XXXIX, abstract no. 1209.
Lorenzetti S., Busemann H., and Eugster O. (2005) Regolith history of lunar meteorites. Meteoritics & Planetary Science 40, 315-327.
Macke R. J., Kiefer W. S., Britt D. T., and Consolmagno G. J. (2010) Density, porosity and magnetic susceptibility of lunar rocks. 41st Lunar and Planetary Science Conference, abstract no. 1252.
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Nishiizumi K. (2003) Exposure histories of lunar meteorites. Evolution of Solar System Materials: A New Perspective from Antarctic Meteorites, 104.
Nishiizumi K. and Caffee M. W. (2001) Exposure histories of lunar meteorites Dhofar 025, 026, and Northwest Africa 482. 64th Annual Meeting, Meteoritical Society, abstract no. 5411.
Puchtel I. S., Walker R. J., Kring D. A., and James O. B. (2007) Further study of 187Os/188Os and highly siderophile element systematics of lunar impact melt rocks. Lunar and Planetary Science XXXVIII, abstract no. 2040.
Puchtel I. S., Walker R. J., James O. B., and Kring D. A. (2008) Osmium isotope and highly siderophile element systematics of lunar impact melt breccias: Implications for the late accretion history of the Moon and Earth. Geochimica et Cosmochimica Acta 72, 3022-3042.
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Warren P. H. and Kallemeyn G. W. (2001) New lunar meteorite Northwest Africa 482: An anorthositic impact melt breccia with low KREEP content. 64th Annual Meeting of the Meteoritical Society, abstract no. 5453.
Warren P. H., Ulff-Møller F., and Kallemeyn G. W. (2005) “New” lunar meteorites: Impact melt and regolith breccias and large-scale heterogeneities of the upper lunar crust. Meteoritics & Planetary Science 40, 989-1014.