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Lunar Meteorite

Northwest Africa 7931

Morocco

 

Northwest Africa 7931
(photo credit: Alexandre Debienne)

 

Lab samples of NWA 7931  
(photo credit: Randy Korotev)

 

from The Meteoritical Bulletin, No. 102.

Northwest Africa 7931

(Northwest Africa)
Purchased: 2013 May
Mass: 5.92 g

Classification: Lunar meteorite (feldspathic breccia)

History: Purchased by Alexandre Debienne in May 2013 from a dealer in Agadir, Morocco.

Physical characteristics: A single small stone (5.92 g) lacking fusion crust.

Petrography: (A. Irving and S. Kuehner, UWS) Breccia consisting of numerous small mineral clasts in partly glassy, vesicular matrix. Minerals are anorthite, olivine, fayalite, pigeonite, ilmenite (with rare baddeleyite inclusions), Ti-rich chromite, troilite and minor kamacite.

Geochemistry: Olivine (Fa44.3-50.2; FeO/MnO = 85-96), orthopyroxene (Fs28.6Wo1.8; FeO/MnO = 60), pigeonite (Fs29.8-41.1Wo11.3-6.6; FeO/MnO = 52-62), ferroan subcalcic augite (Fs54.4Wo36.4; FeO/MnO = 63). Bulk composition (R. Korotev, WUSL): INAA of subsamples gave mean abundances of FeO 7.5 wt.%, and (in ppm) Sc 18, La 3.9, Sm 1.9, Eu 0.74, Yb 1.6, Th 0.6.

Classification: Lunar (feldspathic regolithic breccia).

Specimens: 1.2 g of material is at PSF. The remaining material is with ADebienne

 

Randy Says…

Northwest Africa 7931 is not big, but it appears to be unique.  It’s most similar in composition to the NWA 8673 clan.

 

More Information

Meteoritical Bulletin Database

NWA 7931

References

Korotev R. L. and Irving A. J. (2014) Keeping up with the lunar meteorites — 2014 (abstract). 45th Lunar and Planetary Science Conference, abstract no. 1405.

Sipiera P. P., Irving A. J., Kuehner S. M., Korotev R. L., and Debienne A. (2014) Petrology and composition of unpaired 5.9 gram lunar feldspathic regolithic breccia meteorite Northwest Africa 7931 (abstract). 77th Annual Meeting of the Meteoritical Society, abstract no. 5198.

 

 

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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: 15-Oct-2015