Lunar Meteorite: Northwest Africa 11061

Northwest Africa 11061. Photo credit: Darryl Pitt
Lab sample of NWA 11061. photo credit: Randy Korotev
A clast of ferroan anorthosite in NWA 11061 (upper left). Photo credit: Darryl Pitt)
Two sides of the ferroan anorthosite clast up close (0.5% FeO). Photo credit: Randy Korotev

from The Meteoritical Bulletin, No. 106

Northwest Africa 11061 (NWA 11061)

Northwestern Africa
Purchased: 2016 November
Mass: 1815 g (1 piece)

Lunar meteorite (feldspathic breccia)

History: Purportedly found near the Algeria/Mali border in October 2016, and purchased by Darryl Pitt in November 2016 from a dealer in Mauritania.

Physical characteristics: A single stone (1040 g) lacking fusion crust. The fresh interior exhibits rounded, whitish anorthositic clasts (up to 1.8 cm across) and crystalline debris set in a medium-gray matrix containing obvious small vesicles.

Petrography: (A. Irving and S. Kuehner, UWS) Breccia composed of angular mineral clasts of anorthite, exsolved pigeonite, olivine, orthopyroxene, pigeonite, ilmenite, Ti-chromite, Ti-free chromite, troilite and rare zircon, plus some lithic anorthosite clasts, in a finer grained, partly vesicular matrix of the same minerals.

Geochemistry: Olivine (Fa19.4-52.9, FeO/MnO = 68-91, N = 5), orthopyroxene (Fs23.6Wo3.5, FeO/MnO = 53), pigeonite (Fs36.7Wo15.4, FeO/MnO = 53), low-Ca pyroxene host in exsolved pigeonite (Fs44.5Wo7.1, FeO/MnO = 53), high-Ca pyroxene host in exsolved pigeonite (Fs24.6Wo36.4, FeO/MnO = 52), plagioclase (An97.1-97.6Or0.1, N = 2).

Bulk composition: (R. Korotev, WUSL) INAA of subsamples gave the following mean abundances (in wt.%) FeO 3.4, Na2O 0.32; (in ppm) Sc 6.6, Ni 100, La 1.8, Sm 0.79, Eu 0.78, Yb 0.64, Lu 0.09, Hf 0.58, Th 0.30. Magnetic susceptibility log χ (× 10-9 m3/kg) = 2.61.

Geochemistry: Olivine (Fa35.1; Fa87.0-89.9; FeO/MnO = 91-93, N = 3), pigeonite (Fs41.0Wo7.3; Fs58.3Wo21.3; Fs21.8Wo24.8; FeO/MnO =57-67, N = 3), augite (Fs14.5Wo40.2, FeO/MnO = 45).

Classification: Lunar (feldspathic regolith breccia).

Specimens: 20.7 g including a polished endcut at UWB; remainder with DPitt.

Randy Says…

Compositionally, Northwest Africa 11061 is a typical feldspathic lunar meteorite.

More Information

Meteoritical Bulletin Database

NWA 11061

References

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

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