Lunar Meteorite: Northwest Africa 8632

northwestern Africa

Two views of Northwest Africa 8632 (24 g). photo credit: Luc Labenne

Inside of NWA 86321 8632 (24 g). Photo credit: Luc Labenne

Lab samples of NWA 8632. Photo credit: Randy Korotev

from The Meteoritical Bulletin, No. 103

Northwest Africa 8632 (NWA 8632)

Morocco
Purchased: 2014 June
Mass: 23.8 g (1 piece)

Classification: Lunar meteorite (basalt)

History: Purportedly found near Chwichiya in 2013 and purchased by Luc Labenne in June 2014 from a dealer in Ouarzazate, Morocco.

Physical characteristics: A single, small, dense black stone (23.8 g) with a flat, squarish shape and no fusion crust. Magnetic susceptibility log ? = 3.08 (X in nm3/kg) (J. Gattacceca, CEREGE).

Petrography: (A. Irving and S. Kuehner, UWS) Porphyritic texture. Subhedral zoned olivine phenocrysts (up to 2.3 mm long, yellowish in thin section) are set in a groundmass composed mainly of elongate, zoned clinopyroxene grains (clear with pink rims), smaller olivine grains and interstitial regions (opaque in thin section) consisting of ilmenite needles, Ti-chromite, fine clinopyroxene, fayalite and glass. No plagioclase was found. Small patches and veinlets of pale yellow devitrified glass are present.

Geochemistry: Olivine phenocrysts (cores Fa32.5-32.8, FeO/MnO = 90-100, N = 3; rim Fa48.8, FeO/MnO = 98), groundmass olivine (Fa72.6-74.1, FeO/MnO = 91-97, N = 3), augite (Fs23.7-27.1Wo40.1-40.5, FeO/MnO = 53-55, TiO2 = 2.4-2.6 wt.%, Al2O3 = 5.9- 6.1 wt.%, N = 2), subcalcic augite (Fs26.6-27.0Wo30.8-36.1, FeO/MnO = 54-60, TiO2 = 1.9-2.1 wt.%, Al2O3 = 4.7-5.6 wt.%, N = 2), ferroan subcalcic augite rim (Fs41.9Wo34.1, FeO/MnO = 63, TiO2 = 3.2 wt.%, Al2O3 = 8.1 wt.%).

Bulk composition: (R. Korotev, WUSL) INAA of subsamples gave the following mean abundances (in wt.%) FeO 22.6, Na2O 0.28; (in ppm) Sc 51.1, Ni 70, La 7.8, Sm 4.7, Eu 0.89, Yb 4.1, Lu 0.58, Hf 3.4, Th 1.25.

Classification: Lunar (mare basalt).

Specimens: 4.6 g including one polished thin section, one polished thick section and one polished mount at UWB. The main mass is held by Labenne.

Randy Says…

Northwest Africa 8632 compositionally distinct from any other basaltic lunar meteorites but it may be an olivine-rich pair of NWA 032.

More Information

Meteoritical Bulletin Database

NWA 8632

References

Cato M. J., Fagan A. L. Gross J. (2016) Crystal size distribution of low-Ti lunar basalt-Northwest Africa 8632. 47th Lunar and Planetary Science Conference, abstract no. 2751.

Fagan A. L., Gross J., Ramsey S., and Turrin B. (2018) Northwest Africa 8632- Recording young lunar volcanism. 49th Lunar and Planetary Science Conference, abstract no. 2584.

Fagan A. L., Udry A., Gannon J. P., Cato M. J., and the Spring 2017 WCU Petrology (GEOL 355) class1 (2018) Northwest Africa 8632 – Crystal size distribution variation & potential link to Northwest Africa 032. 49th Lunar and Planetary Science Conference, abstract no. 2601.

Korotev R. L. and Irving A. J. (2015) Keeping up with the lunar meteorites  2015. 46th Lunar and Planetary Science Conference, abstract no. 1942.

Korotev R. L. and Irving A. J. (2021) Lunar meteorites from northern Africa. Meteoritics & Planetary Science, 206–240. 

Korotev R. L., Irving A. J., Wittmann A., Kuehner S. M., Chennaoui-Aoudjehane H., and Labenne L. (2015) Petrology and composition of lunar mare basalt meteorite Northwest Africa 8632 from Chwichiya, Morocco. 46th Lunar and Planetary Science Conference, abstract no. 1195.

Schiller M., Bizzarro M., and Fernandes V. A. (2018) Isotopic evolution of the protoplanetary disk and the building blocks of Earth and the MoonNature 555, 507-510.

Tang C. P, Sawchuk K, and Warren P. H. (2018) A textural/mineralogical gradient within vitrophyric mare basalt Northwest Africa (NWA) 8632. 49th Lunar and Planetary Science Conference, abstract no. 2029.

Webb S., Neal C. R., Gawronska A., and Day J. M. D. (2019) Crystal size distribution patterns for lunar meteorites Northwest Africa 12008, 4898, 8632, 3136 and three LaPaz Icefield lunar meteorites50th Lunar and Planetary Science Conference, abstract no. 2686.

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