Northwest Africa 5000 (NWA 5000)
Achondrite (lunar, feldspathic breccia)
History: Found in July 2007 in southern Morocco and provided to Adam Hupé in October 2007 by a Moroccan dealer.
Physical characteristics: A single, large cuboidal stone (11.528 kg) with approximate dimensions 27 cm × 24 cm × 20 cm. One side (which appears to have been embedded downward in light brown mud) has preserved regmaglypts and is partially covered by translucent, pale greenish fusion crust with fine contraction cracks. Abundant large beige to white, coarse-grained clasts up to 8 cm across (some of which have been eroded out on exterior surfaces of the stone, likely by eolian sand blasting) and sparse black, vitreous clasts up to 2 cm across (containing irregular small white inclusions) are set in a dark gray to black, partially glassy breccia matrix. One partially eroded clast exposed on an exterior surface contains both the coarse grained beige lithology and the more resistant black, vitreous lithology in sharp contact.
Petrography: (A. Irving and S. Kuehner, UWS) Almost monomict fragmental breccia dominated by Mg-suite olivine gabbro clasts consisting predominantly of coarse-grained (0.5-2 mm) calcic plagioclase, pigeonite (some with fine exsolution lamellae), and olivine with accessory merrillite, Mg-bearing ilmenite, Ti-bearing chromite, baddeleyite, rare zirconolite, silica polymorph, K-feldspar, kamacite, and troilite. Some gabbro clasts have shock injection veins composed mostly of glass containing myriad fine troilite blebs and engulfed mineral fragments. Black, vitreous impact melt clasts consist of sporadic, small angular fragments (apparently surviving relics) of gabbro and related mineral phases in a very fine grained, non-vesicular, ophitic-textured matrix of pigeonite laths (up to 20 microns long × 2 microns wide) and interstitial plagioclase with tiny spherical grains of kamacite, irregular grains of schreibersite and rare troilite.
Mineral composition and geochemistry: Gabbro clasts: plagioclase (An96.1-98.0Or<0.1), pigeonite (Fs32.0-64.5Wo6.7-13.1; FeO/MnO = 51.1-62.0), olivine in different clasts range from Fa23.9-24.2, Fa40.4 to Fa58.8 (with FeO/MnO = 81-100), chromite [(Cr/(Cr + Al) = 0.737, Mg/(Mg + Fe) = 0.231, TiO2 = 5.9 wt%], ilmenite (4.1 wt% MgO).
Bulk composition: (R. Korotev, WUSL) INAA of 6 subsamples gave mean values of 5.3 wt% FeO and 0.4 ppm Th.
Classification: Achondrite (lunar, feldspathic breccia). Specimens: A total of 40.2 g of sample, two polished mounts and one large polished thin section are on deposit at UWS. A. Hupé hold the main mass.
At 11.5 kg, Northwest Africa 5000 is one of the largest single-piece lunar meteorites. It is mineralogically and texturally unique among feldspathic lunar meteorites. The light-colored “gabbro” clasts are impact-melt breccia containing iron-nickel metal from the iron meteorite impactor that formed the breccia. The clasts have the composition of a KREEP-poor (0.9 ppm Sm) gabbronoritic anorthosite (5.1% FeO). The composition of the whole rock (sawdust: 5.7% FeO, 2.2 ppm Sm) is consistent with a 1:2 mixture the gabbronoritic clasts and a KREEP-bearing, feldspathic regolith with a composition like the NWA 8641 clan of lunar meteorites (5.1% FeO, 2.9 ppm Sm). The regolith component is carried by the dark matrix of the breccia. I estimate that 0.5% of the mass of the meteorite is FeNi metal and that 9% of the iron in the meteorite is in metallic form.
Meteoritical Bulletin Database
Arai T., Yamamoto A., Ohtake M., Matsunaga T., Haruyama J., Hiroi T., Sasaki S., and Matsui T. (2011) Lunar crustal mineralogy inferred from lunar meteorites and Kaguya data. The 34rd Symposium on Antarctic Meteorites, 3-4.
Arai T., Hiroi T., Sasaki S., and Matsui T. (2013) Origin of the lunar crust inferred from mineralogy and reflectance spectra of lunar meteorites. 44th Lunar and Planetary Science Conference, abstract no. 1016.
Artemieva N. (2014) NWA 5000 — One of a kind? 77th Annual Meeting of the Meteoritical Society, abstract no. 5231.
Fernandes V. A. (2009) 40Ar-39Ar age for gabbroic lunar meteorite Northwest Africa 5000. Geochimica et Cosmochimica Acta Supplement 73, A365.
Fritz J. (2012) Impact ejection of lunar meteorites and the age of Giordano Bruno. Icarus 221, 1183-1186.
Grange M. L. Norman M. D., and Assis Fernandes V. (2016) Clues to the origin of gabbroic lunar meteorite Northwest Africa 5000. 47th Lunar and Planetary Science Conference, abstract no. 1784.
Grange M. L., Norman M. D. and Bennett V. (2016) A Possible 4.1–4.2 Ga impact event recorded in lunar meteorite Northwest Africa 5000. 79th Annual Meeting of the Meteoritical Society, abstract no. 6300.
Hidaka H. and Yoneda S. (2013) Isotopic studies of radiogenic and neutron-captured REE of lunar meteorites. 76th Annual Meeting of the Meteoritical Society, abstract no. 5042.
Humayun M. and Irving A. (2008) Impactor metal in gabbroic lunar meteorite Northwest Africa 5000. Goldschmidt Conference Abstracts 2008, Geochimica et Cosmochimica Acta 72, 12S, A402.
Irving A. J., Kuehner S. M., Korotev R. L., Rumble D. III, and Hupé A. C. (2008) Petrology and bulk composition of large lunar feldspathic leucogabbroic breccia Northwest Africa 5000. Lunar and Planetary Science XXXIX, abstract no. 2186.
Korotev R. L. (2013) Siderophile elements in brecciated lunar meteorites. 44th Lunar and Planetary Science Conference, abstract no. 1028.
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., Jolliff B. L., and Zeigler R. A. (2010) On the origin of the moon’s feldspathic highlands, pure anorthosite, and the feldspathic lunar meteorites. 41st Lunar and Planetary Science Conference, abstract no. 1440.
Macke R. J., Kiefer W. S., Britt D. T., Irving A. J., and Consolmagno G. J. (2011) Densities, porosities and magnetic susceptibilities of meteoritic lunar samples: Early results. 42nd Lunar and Planetary Science Conference, abstract no. 1986.
Macke R. J., Britt D. T., and Consolmagno G. J. (2011) Density, porosity and magnetic susceptibility of achondritic meteorites. Meteoritics & Planetary Science 46, 311-326.
Masahiro M., Tomioka N., Ohtani E., Seto Y., Nagaoka H, Götze J, Miyake A., Ozawa S., Sekine T., Miyahara M., Tomeoka K., Matsumoto M., Shoda N., Hirao N., and Kobayashi T. (2018) Discovery of moganite in a lunar meteorite as a trace of H2O ice in the Moon’s regolith. Science Advances, 4, eaar4378
Nagurney A. B., Treiman A. H., and Spudis P. D. (2016) Petrology, bulk composition, and provenance of meteorite Northwest Africa 5000. 46th Lunar and Planetary Science Conference, abstract no. 1103.
Nishiizumi K., Caffee M. W., Vogel N., Wieler R., Leclerc M. D., and Jull A. J. T. (2009) Exposure history of lunar meteorite Northwest Africa 5000. 40th Lunar and Planetary Science Conference, abstract no. 1476.
Worsham E. A. and Kleine T. (2020) Constraining the late heavy bombardment of the Moon using Ru isotopes in lunar impactites. 51st Lunar and Planetary Science Conference, abstract no. 2811.
Zhang Z. F., Wu W., Li X., and An Y. J. (2019) Calcium isotopic composition of the KREEPs. 82nd Annual Meeting of the Meteoritical Society, abstract no. 6013.