Lunar Meteorite: Northwest Africa 482

Morocco or Algeria

Northwest Africa 482 appears very fresh, with a shiny fusion crust and flow lines.  Clasts are visible through the fusion crust. Photo credit: Jim Strope

It has some nice regmaglypts. Photo credit: Jim Strope

Sawn face of NWA 482, with melt veins. Photo credit: Jim Strope

Lab samples. Photo credit: Randy Korotev

from The Meteoritical Bulletin, No. 85

Northwest Africa 482

(Northwest Africa)

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.

Randy Says…

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.

More Information

Meteoritical Bulletin Database

NWA 482

References

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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 highlandsMeteoritics & Planetary Science 37, 1797-1814.

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