Lunar Meteorite: Northwest Africa 7022

Algeria?

Northwest Africa 7022. Photo credit: Jason Utas

Two slices of NWA 7022 Photo credits: Marlin Cilz (left) and Tony Irving (right)

Lab samples of NWA 7022: fragmental breccia (top) and melt-breccia clast (bottom). Photo credit: Randy Korotev

from The Meteoritical Bulletin, No. 100

Northwest Africa 7022 (NWA 7022)

Algeria?
Purchased: 2011 Mar
Mass: 466 g (1 piece)

Lunar meteorite (feldspathic breccia)

History: Reported to be found near Tandouf, Algeria, in February 2011, and purchased from a dealer in Zagora, Morocco by Peter Utas in March 2011.

Physical characteristics: A single stone (466 g) with partial fusion crust. About two-thirds of the stone consists of a fragmental breccia composed of a variety of lighter colored, mostly angular mineral and rock clasts in a dark-gray matrix. The other one-third of the stone is comprised of a single large (to 4 cm), light-gray, fine-grained clast (which itself contains small remnant clasts).

Petrography: (A. Irving and S. Kuehner, UWS) The large, light-gray clast contains sparsely-distributed angular grains of olivine and calcic plagioclase set in a melt-textured (intersertal) aggregate of calcic plagioclase and both low-Ca and high-Ca pyroxenes, with accessory skeletal ilmenite, armalcolite, fayalite, troilite, silica polymorph, baddeleyite, merrillite, kamacite and rare zircon. The complex dark matrix portion consists of angular grains of olivine, low-Ca pyroxene, calcic plagioclase, Ti-bearing chromite, silica polymorph, silica+K-feldspar intergrowths, kamacite, feldspar-rich clasts (including additional melt-textured clasts), and sparse glass fragments containing tiny vesicles.

Geochemistry: Olivine (Fa40.6-47.6, Fe/Mn=114-117), low-Ca pyroxene (Fs22.8-28.8Wo5.9-6.5, Fe/Mn=52-61), high-Ca pyroxene (Fs26.4-28.8Wo22.2-18.3, Fe/Mn=58-74), plagioclase (An91.5-94.8Or0.4-0.2).

Classification: Achondrite (lunar, feldspathic breccia). Terrestrial weathering is minimal.

Specimens: A total of 21.6 g of sample is on deposit at UWS. The main mass is held by Peter Utas.

Randy Says…

NWA 7022 is a KREEP-bearing feldspathic lunar meteorite. The dark breccia lithology is indistinguishable in composition from MIL 090036.

More Information

Meteoritical Bulletin Database

NWA 7022

References

Joy K. H., Burgess R., Ruzie L, and Clay P. L. (2014) Composition, age and regolith history of feldspathic lunar meteorites. 77th Annual Meeting of the Meteoritical Society, abstract no. 5345.

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 – 201243rd Lunar and Planetary Science Conference, abstract no. 1152.

Kuehner S. M., Irving A. J., and Korotev R. L. (2012) Petrology and composition of lunar meteorite Northwest Africa 7022: An unusually sodic anorthositic gabbroic impact melt breccia with compositional similarities to Miller Range 090036Lunar and Planetary Science XLIII, abstract no. 1524.

Nishiizumi K. and Caffee M. W. (2013) Relationships among six lunar meteorites from Miller Range, Antarctica based on cosmogenic radionuclides44th Lunar and Planetary Science Conference, abstract no. 2715.

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