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Lunar Meteorite

Northwest Africa 4884

northern Africa

 

Northwest Africa 4884
(photo credit: by Greg Hupé)

 

NWA 4884 in the lab.  Click on image for enlargement.
(photo credit: Randy Korotev)

 

from The Meteoritical Bulletin, No. 93, Meteoritics & Planetary Science 43, 571–632 (2007)

Northwest Africa 4884

Northwest Africa
Find: 2007 July
Mass: 42 g

Achondrite (lunar, mingled basalt-rich breccia)

History: Purchased by Greg Hupé in July 2007 from a dealer in Tagounite, Morocco.

Physical characteristics: A single stone (42 g) partially covered by black fusion crust; interior slices show it to be a breccia composed of white, beige and light gray clasts in a dark gray matrix (see image).

Petrography: (A. Irving and S. Kuehner, UWS) Regolithic breccia composed of abundant angular mineral and lithic clasts in a sparse vesicular, glassy matrix. Mineral fragments include calcic plagioclase, pigeonite, augite, Ti-chromite, ilmenite (one with a tiny baddeleyite inclusion) and silica polymorph. Lithic clasts include several types of mare basalt (a coarse-grained example is composed of olivine+zoned pigeonite+calcic plagioclase+ilmenite+troilite), granophyric intergrowths of Fe-rich augite+fayalitic olivine+silica polymorph, a coarse grained dunitic or troctolitic rock containing a large metal grain (associated with rutile and secondary ilmenite), and a large “breccia-within-breccia” clast. Mare basalt clasts and debris are predominant over highlands lithologies.

Geochemistry: Olivine clasts (Fa37.0-37.7; FeO/MnO = 94-98), olivine in basalt clast (Fa87.9; FeO/MnO = 89), plagioclase (An92.4-95.3Or0.5-0.1), pigeonite host (Fs52.3Wo10.5; FeO/MnO = 65.2), augite lamella (Fs31.9Wo31.9; FeO/MnO = 60.3), pigeonite clast (Fs60.1Wo7.0, FeO/MnO = 71.1), augite clast (Fs17.2Wo36.9, FeO/MnO = 53.3). Bulk composition: (R. Korotev, WUSL) FeO = 13.7 wt%; Sm = 3.1 ppm, Th = 0.9 ppm, Ir 3.4 ppb.

Classification: Achondrite (lunar, mingled basalt-rich breccia).

Specimens: A total of 8.4 g of sample and one polished mount are on deposit at UWS. GHupé holds the main mass.

 

Randy Says…

NWA 4484 is a basalt-rich regolith breccia that is compositionally and texturally very similar to NWA 7611 and pairs. These meteorites are likely part of a large launch-pair group that also includes QUE 94281 (Antarctica), Yamato 793274/981031, (Antarctica), and DEW 12007 (Antarctica) and, possibly, EET 87521/96008  (Antarctica).

 

More Information

Meteoritical Bulletin Database

NWA 4884

References

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.

Korotev R. L, Zeigler R. A., Jolliff B. L., Irving A. J., and Bunch T. E. (2009) Compositional and lithological diversity among brecciated lunar meteorites of intermediate iron composition. Meteoritics & Planetary Science 44, 1287-1322.

 

Nishiizumi K., Caffee M. W., and  Jull A. J. T. (2016) Exposure history of Mount DeWitt 12007 and proposed launch-paired Northwest Africa 4884, 7611, and 8277 lunar meteorites (abstract). 79th Annual Meeting of the Meteoritical Society, abstract no. 6514.

 

 

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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: 28-June-2016