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Lunar Meteorite: Northwest Africa 482

Morocco/Algeria

The meteorite appears very fresh, with a shiny fusion crust and flow lines.  Clasts are visible through the fusion crust.  (Click on image for an enlargement.)
Note these additional features that are also characteristic of meteorites, but not of "meteorwrongs:"
  • there are no sharp angles or edges in portions of the meteorite covered by fusion crust
  • the presence of ablation scoops and pits
photos courtesy of Jim Strope

from The Meteoritical Bulletin, No. 85, Meteoritics & Planetary Science 36, A293-A322 (2001)

Northwest Africa 482

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.

More Information

http://www.lunarrock.com/

Meteoritical Bulletin Database

NWA 482

References

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 (abstract). Lunar and Planetary Science XXXV, abstract no. 1370, Lunar and Planetary Institute, Houston.

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, Meteorit. Planet. Sci. 37, 1797-1814.

Korotev R. L. (2005) Lunar geochemistry as told by lunar meteorites. Chemie der Erde 65, 297–346.

Korotev R. L., Irving A. J., and Bunch T. E. (2008) Keeping up with the lunar meteorites – 2008 (abstract). In Lunar and Planetary Science XXXIX, abstract no. 1209, 39th Lunar and Planetary Science Conference, Houston.

Lorenzetti S., Busemann H., and Eugster O. (2005) Regolith history of lunar meteorites. Meteor. Planet. Sci. 40, 315-327.

Nishiizumi K. and Caffee M. W. (2001) Exposure histories of lunar meteorites Dhofar 025, 026, and Northwest Africa 482 (abstract), Meteorit. Planet. Sci. 36, A148–A149, 64th Annual Meeting, Meteoritical Society.

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 (abstract). In Lunar and Planetary Science XXXVIII, abstract no. 2040, 38th Lunar and Planetary Science Conference, Houston.

Warren P. H. and Kallemeyn G. W. (2001) New lunar meteorite Northwest Africa 482: An anorthositic impact melt breccia with low KREEP content (abstract), Meteorit. Planet. Sci. 36, A220, 64th Annual Meeting, Meteoritical Society.

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. Meteorit. Planet. Sci. 40, 989–1014.

Chemical Classification

Overview | NWA 482


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Prepared by:

Randy L. Korotev

Department of Earth and Planetary Sciences
Washington University in St. Louis

Please don't contact me about the meteorite you think you’ve found until you read this and this.

e-mail: korotev@wustl.edu

Last revised: 08-Feb-2008