Lunar Meteorite: Northwest Africa 6888

A slice of Northwest Africa 6888. Photo credit: Heritage Auctions
A different slice of Northwest Africa 6888. Photo credit: Doug Ross
Another slice of NWA 6888. The contrast has been stretched to emphasize the clasts.  Thanks to Serge Afanasyev for the sample. Photo credit: Randy Korotev
Image of a thick (100 µm) section of NWA 6888. Maximum width: 11 mm. Photo credit: Randy Korotev

from The Meteoritical Bulletin, No. 100

Northwest Africa 6888 (NWA 6888)

Western Sahara
Find: 2011 May 28
Mass: 208 g (1 piece)

Lunar meteorite

History: The meteorite was found by anonymous finder on the Sueilila (Zwilila) limestone plateau, ~40 km E of Hassi Lakra (Playa del Cordero) station, in the desert.

Physical characteristics: One brownish-grey to dark green stone weighing 208 g in total, with no fusion crust.

Petrography: (Lorenz C.A., Ivanova M.A., and Demidova S.I. Vernad.) The meteorite is polymict, melt matrix breccia, consisting of numerous mineral and lithic fragments embedded in a fine-grained devitrified matrix. Lithic clasts dominated by melt breccias, granulites, anorthosites, gabbro, gabbro-norites, troctolites and VLT-like basalts. Rare spherules of devitrified glass occur. The size range of the clasts is 0.02-9 mm; the main minerals are pyroxene and feldspar; minor – olivine, silica, chromite, ilmenite, Zr-armolcolite, troilite, and FeNi metal.

Geochemistry: (Kononkova N.N., Vernad, EMP) feldspar An91-97Ab2.8-6.0; clinopyroxene En7.7-68.3Wo5.1-42.0, orthopyroxene En44.4-75.0Wo2.6-4.9 (FeO/MnO = 60.03), olivine Fo4.7-63.3 (FeO/MnO = 87); ilmenite (MgO 0.24-4.02 wt%), Al,Ti-chromite (TiO2 8.4 wt%, Al2O3 8.2 wt%) and ulvospinel. FeNi metal: 0.68-9.51 wt% Ni; 0.40-2.27 wt% Co; sulfide is troilite.

Classification: Lunar (regolith breccia). The grade of weathering is moderate.

Specimens: A total of 21.7 g of sample and two thin sections are on deposit at Vernad. An anonymous finder holds the main mass of the meteorite.

Randy Says…

Compositionally, NWA 6888 is a bit more mafic than a typical feldspathic lunar meteorite, probably because of the basalt clasts.

More Information

Meteoritical Bulletin Database

NWA 6888

References

Demidova S. I., Nazarov M. A., Ivanova M. A., Lorenz K. A., and Kononkova N. N. (2012) New lunar meteorite from the Sahara Desert: North West Africa 6888. 43rd Lunar and Planetary Science Conference, abstract no. 1726.

Korochantseva E. V., Buikin A. I., Hopp J., Korochantsev A. V., and Trieloff M. (2016) 40Ar-39Ar results of lunar meteorites Dhofar 025, 280, 309, 730, 733, 1436, 1442, SaU 449, NWA 6888. 79th Annual Meeting of the Meteoritical Society, abstract no. 6317.

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. (2012) Keeping Up With the Lunar Meteorites – 2012. 43rd Lunar and Planetary Science Conference, abstract no. 1152.

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