Northwest Africa 4884 (NWA 4884)
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.
NWA 4484 is a basalt-rich regolith breccia that is compositionally and texturally very similar to the NWA 7611 clan. These meteorites are likely part of a large launch-pair group that also includes QUE 94281, Yamato 793274/981031, and DEW 12007, all from Antarctica. See the NWA 7611 clan for more info.
Meteoritical Bulletin Database
Cao H., Ling Z. C., Chen J., Fu X. H., and Gu X. (2018) Petrography and mineralogy of Northwest Africa (NWA) 4884 with Raman spectroscopy. 49th Lunar and Planetary Science Conference, abstract no. 2176.
Korotev R. L. and Irving A. J. (2021) Lunar meteorites from northern Africa. Meteoritics & Planetary Science, 206–240.
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.
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. 79th Annual Meeting of the Meteoritical Society, abstract no. 6514.