Lunar Meteorite: Northwest Africa 5744 clan

from The Meteoritical Bulletin, No. 96

Northwest Africa 5744 (NWA 5744)

Mali
Find: 2009 February
Mass: 170 g (1 piece)

Achondrite (lunar, granulitic troctolitic breccia)

History: Found near Gawa, Mali, in February 2009 and purchased from a dealer by Adam Aaronson.

Physical characteristics: A single, buff-colored, rounded stone (170 g) lacking fusion crust (Fig. 2). Small white clasts are visible in a pale, finer grained matrix.

Petrography: (A. Irving and S. Kuehner, UWS; T. Bunch, NAU): Recrystallized breccia composed mainly of plagioclase (up to 100 µm) with fine-grained (<50 µm) olivine, pigeonite, orthopyroxene, and accessory Ti-chromite and Ni-bearing troilite.

Geochemistry: Plagioclase (An_97.9Or_0.1), olivine (Fa_20.7, FeO/MnO = 76.9–94.5), pigeonite (Fs_16.6Wo_9.7, FeO/MnO = 50).

Bulk composition: (R. Korotev, WUSL): INAA on a 185 mg fragment gave FeO 5.7 wt%, Na₂O 0.25 wt%; Sc 8.3, Cr 1050, La 1.1, Sm 0.47, Eu 0.58, Yb 0.42, Th 0.15, all in ppm.

Classification: Achondrite (lunar, granulitic troctolitic breccia).

Specimens: A total of 13.1 g and two polished thin sections are on deposit at UWS; a 7.1 g of sample is at NAU. The main mass is held by an anonymous collector.

from The Meteoritical Bulletin, No. 103

Northwest Africa 8599 (NWA 8599)

(Northwest Africa)
Purchased: 2014 June
Mass: 36.5 g (1 piece)

Lunar Meteorite

History: Purchased by F. Kuntz in June 2014 from a dealer in Zagora, Morocco.

Physical characteristics: Smooth-surfaced, fine grained, greenish-gray stone (36.5 g) with cross-cutting black veins.

Petrography: (A. Irving and S. Kuehner, UWS) Granuloblastic texture with larger grains of anorthite and very small grains of olivine, low-Ca pyroxene, high-Ca pyroxene, Al-bearing chromite, trolite and taenite.

Geochemistry: Olivine (Fa_23.3-23.5, FeO/MnO = 81-83), low-Ca pyroxene (Fs_18.9-19.6Wo_5.2-4.7; FeO/MnO = 53-58), high-Ca pyroxene (Fs_9.8Wo_40.6, FeO/MnO = 59), plagioclase (An_97.0-97.1Or_0.1).

Bulk composition: (R. Korotev, WUSL) INAA of subsamples gave the following mean abundances (in wt.%) FeO 5.4, Na₂O 0.23; (in ppm) Sc 7.1, Ni 140, La 0.71, Sm 0.37, Eu 0.55, Yb 0.34, Lu 0.05, Hf 0.23, Th 0.08.

Classification: Lunar (troctolitic granulitic breccia). On the basis of essentially identical texture, mineralogy and bulk composition, this specimen is paired with NWA 5744.

Specimens: 7.47 g including one polished slice at PSF; main mass with Kuntz.

from The Meteoritical Bulletin, No. 103

Northwest Africa 8687 (NWA 8687)

(Mauritania)
Found: 2014 April
Mass: 563 g (5 pieces)

Lunar Meteorite (troctolite)

History: Purchased by Adam Aaronson in Morocco, 2014.

Physical characteristics: Five pieces, no fusion crust, smooth, light green-tan color, sandblasted exterior, saw cut and polished surface reveals fine-grained, pale green interior with fine shock melt veining.

Petrography: (C. Agee, UNM) Microprobe examination of a ~30 × 15 mm, polished, saw-cut surface of the deposit sample, shows a monomict breccia with approximately 70% plagioclase, 25% olivine, 3% orthopyroxene. Primarily fine grained plagioclase, olivine, and orthopyroxene 5-50 µm, scattered larger plagioclase and olivine 200-500 µm, some poikioblastic plagioclase with fine-grained olivines and pyroxenes. Shock melt veins are found throughout. Scatterered Ti-chromite grains up to 100 µm, other accessory phases include FeNi-metal, troilite, ilmenite, and apatite. Minor pigeonite and augite present.

Geochemistry: (C. Agee and N. Muttik, UNM). olivine Fa_21.7±2.2, Fe/Mn=88±5, n=24; low-Ca pyroxene Fs_19.6±2.3Wo_3.5±1.4, Fe/Mn=54±3, n=11; pigeonite Fs_16.8Wo_19.1, Fe/Mn=41, n=1; augite Fs_11.3Wo_37.2, Fe/Mn=41, n=1; plagioclase An_96.7±0.8Ab_3.1±0.8Or_0.2±0.0, n=7; Shock melt (20 µm defocused electron beam, proxy for bulk meteorite composition): SiO₂=43.01±0.66, TiO₂=0.14±0.03, Al₂O₃= 23.85±2.94, Cr₂O₃=0.15±0.05, MgO=12.11±3.05, FeO=5.20±1.17, MnO=0.06±0.01, CaO=13.48±1.32, NiO=0.02±0.02, Na₂O=0.25±0.05, K₂O=0.03±0.00 (all wt%), Fe/Mn=84±29, Mg#=80.5±0.8, n=5.

Classification: Achondrite (lunar troctolite), low weathering grade, high shock stage, likely paired with NWA 5744.

Specimens: A total of 21.5 g including a probe mount on deposit at UNM. Aaronson holds the main mass.

from The Meteoritical Bulletin, No. 104

Northwest Africa 10140 (NWA 10140)

(Northwest Africa)
Purchased: 2015 February
Mass: 68 g (1 piece)

Lunar Meteorite (troctolitic anorthosite)

History: Purchased by Larry Atkins in Morocco in February 2015.

Physical characteristics: Single stone. A saw cut reveals a very fine-grained, light-gray groundmass, crosscut by numerous shock melt veins some up to 3 mm.

Petrography: (C. Agee, UNM) This meteorite is a fine-grained anorthositic troctolite (Prinz and Keil, 1977) with plagioclase (75%), olivine (15%), and low-Ca pyroxene (10%) as dominant silicate phases. There are numerous shock melt domains present, some with quench spinifex textures. Accessory troilite and chromite were observed.

Geochemistry: (C. Agee and N. Muttik, UNM) olivine Fa_23.4±2.8, Fe/Mn=90±4, n=11; low Ca pyroxene Fs_20.5±1.1Wo_3.7±0.9, Fe/Mn=56±6, n=9; plagioclase An_97.1±1.0Ab_2.7±1.0Or_0.2±0.0, n=5; Shock melt (20 µm defocused electron beam, proxy for bulk meteorite composition): SiO₂=42.1±0.3, TiO₂=0.13±0.04, Al₂O₃=27.3±3.1, Cr₂O₃=0.11±0.04, MgO=7.8±2.7, FeO=4.4±1.5, MnO=0.05±0.02, CaO=15.4±1.4, NiO=0.00±0.00, Na₂O=0.27±0.03, K₂O=0.00±0.00 (all wt%), Fe/Mn=89±35, Mg#=75.9±0.8, MgO+FeO=12.1±4.2 (wt%), n=12.

Classification: Lunar (troctolitic anorthosite) based on Stöffler et al. (1980).

Specimens: 14 g including a probe mount on deposit at UNM, Larry Atkins holds the main mass.

from The Meteoritical Bulletin, No. 104

Northwest Africa 10178 (NWA 10178)

(Northwest Africa)
Purchased: 2015
Mass: 1279.3 g (3 pieces)

Lunar Meteorite (troctolitic anorthosite)

History: Purchased by Darryl Pitt in February, March and May 2015 from Moroccan dealers.

Physical characteristics: Three similar, very fine grained, brittle stones (556.3 g, 310 g, 413 g) containing larger grains of maskelynite, and with cross-cutting, anastomozing veinlets of green glass.

Petrography: (A. Irving and S. Kuehner, UWS) Very fine-grained breccia composed of abundant anorthite (converted to maskelynite), olivine, orthopyroxene and pigeonite with accessory chromite and troilite.

Geochemistry: Olivine (Fa_22.7-23.0, FeO/MnO = 87-91, N = 3), orthopyroxene (Fs_18.7-18.8Wo_2.9-3.2, FeO/MnO = 47-61, N = 2), maskelynite (An_95.9-97.4Or₀, N = 2).

Classification: Lunar (troctolitic granulitic breccia). Paired with NWA 5744 and others based on distinctive textural and mineralogical similarities.

Specimens: 40.4 g including one polished endcut at UWB. The remainder is held by DPitt.

from The Meteoritical Bulletin, No. 104

Northwest Africa 10318 (NWA 10318)

Morocco
Purchased: 22 Apr 2015
Mass: 31.0 g (1 piece)

Classification: Lunar meteorite

History: An individual of 31.0 g was found in Morocco and purchased from a Moroccan meteorite dealer in Dakhla, Morocco, April 22, 2015.

Petrography: (A. Bischoff and S. Ebert, IfP) This meteorite is a severely shocked rock with maskelynite (~65-75%), olivine (~10%), and low-Ca pyroxene (~15-20%) as dominant silicate phases. The mafics occur as rounded phases poikilitically enclosed in maskelynite. The shock veins probably formed after the shock that transformed the plagioclase to maskelynite, because they cut through homogenous maykelynite areas. Accessory phases were observed include troilite and chromite.

Geochemistry: Mineral compositions and geochemistry: Olivine Fa_26.4±0.6, Fe/Mn=97, n=11; low-Ca-pyroxene Fs_21.8±0.7Wo_5.0±2.0, Fe/Mn=54, n=11; plagioclase An_97.1±0.6, range: An_96.0-98.2 mol% An; n=10.

Classification: Achondrite (lunar, granulitic breccia of olivine-bearing anorthositic norite precursor), low weathering grade, high shock stage (S5).

Specimens: A total of 6.2 g including a thin section on deposit at IfP. S. Decker (Meteorite-Museum, 55430 Oberwesel, Germany) holds the main mass.

from The Meteoritical Bulletin, No. 104

Northwest Africa 10401 (NWA 10401)

(Northwest Africa)
Purchased: 2015
Mass: 354 g (2 pieces)

Classification: Lunar meteorite

History: Purchased by Steve Arnold from a dealer in Ouarzarete, Morocco in 2015.

Physical characteristics: Two stones totaling 354 g (218 and 136 g). A sawed piece from one of the stones reveals a very fine-grained, light-gray groundmass that is cross-cut by several shock melt veins. Larger white clasts within the groundmass are present.

Petrography: A. Hilton (CoW), J. Gross (Rut). This meteorite is an anorthositic troctolite with a granulitic texture. It contains plagioclase (59-65%), olivine (23-26%), orthopyroxene, and clinopyroxene (pyx total: 12-15%) as the main silicate phases. Accessory grains of spinel were observed. Microprobe examination shows two particularly large clasts (diameters 3.1-4.7 mm) surrounded by a light-gray, fine-grained matrix and many smaller clasts (0.1-0.8 mm). The sample is crosscut by an abundant number of thin shock melt veins. The veins show compositional variation as well as partial assimilation of surrounding grains in some areas and are homogeneous in others. Plagioclase grains (0.2-0.8 mm) are angular and sub-euhedral in shape, while mafic clasts rich in olivine and pyroxene (0.1-0.3 mm) are composed of small (<10-35 μm) anhedral olivine and pyroxene grains. Single anhedral grains of olivine and pyroxene are also present in the sample, including some that exhibit pyroxene exsolution lamellae. The matrix is composed of small, granular, anhedral grains of olivine and pyroxene that appear to outline grain boundaries of plagioclase fragments.

Geochemistry: J. Gross (Rut) and A. Hilton (CoW). Olivine Fa_18.6±2 (N=180), Fe/Mn=88.1±8.3; Orthopyroxene: Fs_15.5±2Wo­En­, Fe/Mn=49.3±6 (N=48); Clinopyroxene: Fs_9.0±1.4Wo_41.3±7.9 En_49.7±6.8, Fe/Mn=37.2±4 (N = 20); Plagioclase An_96.6±0.3Ab_2.9±0.6Or_0.1±0.05 (N=254). The shock melt vein (defocused electron beam as proxy for bulk composition) has an average composition of: Na₂O = 0.27±0.1, MgO = 9.7±0.3, SiO₂ = 45±0.8, Al₂O₃ = 26±0.6, P₂O₅ = 0.02±0.04, K₂O = 0.01±0.01, CaO = 15±6, TiO₂ = 0.12±0.03, MnO = 0.06±0.04, FeO = 4.1±0.3, BaO = 0.01±0.03 Cr₂O₃ = 0.13±0.03, NiO = 0.02±0.02, N=74.

Bulk composition: (R. Korotev, WUSL): INAA on a 99 mg fragment gave FeO 6.1 wt%, Na₂O 0.24 wt%; Sc 8.7, Cr 1300, Ni 124, La 0.65, Sm 0.38, Eu 0.55, Yb 0.37, Th 0.07, all in ppm.

Classification: Lunar (anorthositic troctolitic breccia with granulitic texture)

Specimens: 20 g at TCU, thick section probe mount at RU; Peter Scherff holds the main mass.

from The Meteoritical Bulletin, No. 106

Northwest Africa 11252 (NWA 11252)

(Northwest Africa)
Purchased: 2017 January
Mass: 22.9 g (1 piece)

Classification: Lunar meteorite (troctolitic anorthosite)

History: Purchased by Khalid Boushaba in January 2017 from a dealer in Erfoud, Morocco.

Physical characteristics: A single, small beige-colored stone (22.9 g) lacking fusion crust, but with visible grains of maskelynite and some cross-cutting, dark glassy veinlets.

Petrography: (A. Irving and S. Kuehner, UWS) Very fine grained assemblage dominated by anorthite (maskelynite) with olivine, pigeonite, subcalcic augite, augite, chromite (with a range of Ti contents), ilmenite, troilite, taenite and minor glass (in veins).

Geochemistry: Olivine (Fa_22.4-45.1, FeO/MnO = 98-112, N = 3), pigeonite (Fs_15.0-16.9Wo_13.9-10.2, FeO/MnO = 51-66, N = 3), subcalcic augite (Fs_16.6Wo_34.4, FeO/MnO = 52), augite (Fs_10.3Wo_41.7, FeO/MnO = 49), maskelynite (An_96.9-98.3Or_0.2, N = 2).

Classification: Lunar (feldspathic troctolitic granulitic breccia).

Specimens: 4.6 g including one polished mount at UWB; remainder with Mr. K. Boushaba.

from The Meteoritical Bulletin, No. 108

Northwest Africa 12997 (NWA 12997)

(Northwest Africa)
Purchased: 2015
Mass: 60 g (many pieces)

Classification: Lunar  (troctolite)

History: Found by unknown nomads (date and location unconfirmed). Purchased in 2015 in Morocco by Graham Ensor.

Physical characteristics:  Light grey sandblasted exterior, with visible dark melt veins visible on exterior and interior of rock. No fusion crust. Cumulus olivine and plagioclase.

Petrography: (T. S. Hayden, M. Anand, T. J. Barrett, OU). The meteorite is a cumulate troctolite mainly comprising olivine and plagioclase crystals, with minor pyroxene. Accessory phases include ilmenite, spinel, merrillite and chromite.

Geochemistry: Mineral Composition and Geochemistry: (T. S. Hayden, M. Anand, T. J. Barrett, OU) Feldspar (An_96.6±1.0Ab_3.4±1.0, N = 13), Pigeonite (Fs_22.3±8.2Wo_9.7±5.4, Fe/Mn = 46.7±8.7, N=6), Augite (Fs_11.3±1.2Wo_37.0±1.7, Fe/Mn = 28.0±3.5, N=3), Clinoenstatite (Fs_19.3±1.3Wo_3.5±0.8, Fe/Mn = 47.4±4.2, N=8), Olivine (Fa_22.9±1.2, Fe/Mn = 88.1±5.9, N=21). O isotopes (measured at OU): Repetition 1: δ¹⁷O = 3.092‰, δ¹⁸O = 5.916‰, Δ¹⁷O = -0.008‰, Repetition 2: δ¹⁷O = 3.057‰, δ¹⁸O = 5.844‰, Δ¹⁷O = -0.005‰. Mean: δ¹⁷O = 3.0745±0.025‰ (1-sigma), δ¹⁸O = 5.880±0.051‰ (1-sigma), Δ¹⁷O = -0.006±0.002‰ (1-sigma) (linearized using a slope of 0.5247 (of Miller, 2002)).

Classification: Lunar troctolite. Thought to be paired with NWA 5744 clan based on textural and mineralogical similarities.

Specimens: Specimen: 16.8 g specimen held at OU. Graham Ensor holds the main mass (two stones weighing 60 g).

Randy Says…

I have chemically analyzed 10 of these stones. They overlap in composition and together are different from any other lunar meteorite or, in detail, any Apollo sample in being anorthositic troctolite in composition and poor in KREEP (0.35 ppm Sm). Three stones are unnamed because no type specimens have been submitted for classification. I have not studied NWA 12977 but assume that is is a stone of the pair group from the description.

More Information

Meteoritical Bulletin Database

NWA 5744 | 8599 | 8687 | 10140 | 10178 | 10318 | 10401 | 11252

References

Consolmagno G. J., Macke R. J., Opeil C. P., and Britt D. T. (2023) Thermal and physical properties of lunar meteorites at low temperatures. 86th Annual Meeting of the Meteoritical Society, abstract no. 6092.

Gross J., Prissel T. C., Korotev R. L., Parman S. W. (2017) Unique pink spinel symplectite assemblage in Northwest Africa (NWA) 10401: Breakdown reaction through solid-state diffusion and potential relation to Apollo 17 samples. 48 Lunar and Planetary Science XLVIII, abstract no. 2589.

Gross J., Hilton A.,  Prissel T. C., Setera J. B., Korotev R. L., and  Calzada-Diaz A. (2020) Geochemistry and petrogenesis of Northwest Africa 10401: A new type of the Mg-suite rocks? Journal of Geophysical Research Planets 125, May, e2019JE006225.

Hidaka H., Nishiizumi K., Caffee M., and Yoneda S. (2024) Ytterbium isotopic compositions of lunar meteorites. 86th Annual Meeting of the Meteoritical Society, abstract no. 6114.

Hilton A., Gross J., Korotev, R., and Calzada-Diaz A. (2016) Classifying the unknown — The lunar edition: North West Africa 10401 a new type of the Mg-suite rock? 47th Lunar and Planetary Science Conference, abstract no. 1168.

Kent J. J., Brandon A. D., Lapen T. J., Peslier A. H., Irving A. J., and Coleff D. M. (2012) In situ chemical characterization of mineral phases in lunar granulite meteorite Northwest Africa 5744. 43rd Lunar and Planetary Science Conference, abstract no. 2559.

Kent J. J., Brandon A. D., Joy K. H., Peslier A. H., Lapen, T. J., Irving A. J., and Coleff D. M (2017) Mineralogy and petrogenesis of lunar magnesian granulitic meteorite Northwest Africa 5744. Meteoritics & Planetary Science 52, 1916-1940.

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. (2015) Keeping up with the lunar meteorites – 2015. 46th Lunar and Planetary Science Conference, abstract no. 1942.

Korotev R. L. and Irving A. J. (2016) Not quite keeping up with the lunar meteorites – 2016. 47th Lunar and Planetary Science Conference, abstract no. 1358.

Korotev R. L. and Irving A. J. (2017) Still not keeping up with the lunar meteorites – 2017. Lunar and Planetary Science XLVIII, abstract no. 1498.

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

Kuehner S. M., Irving A. J., Gellissen M., and Korotev R. L. (2010) Petrology and composition of lunar troctolitic granulite Northwest Africa 5744: A unique recrystallized, magnesian crustal sample. 41st Lunar and Planetary Science Conference, abstract no. 1552.

Macke R. J., Opeil C. P., Britt D. T., Consolmagno G. J., Irving A. (2024) Low-temperature thermal and physical properties of lunar meteorites. Meteoritics & Planetary Science 59, 1610-1631. https://doi.org/10.1111/maps.14171

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

Robinson K. L. and Kring D. A. (2018) The Northwest Africa 5744 group: A glimpse into Schrödinger-like lithologies? 49th Lunar and Planetary Science Conference, abstract no. 1635.

Zhou Q., Zhang G. L., Zhu X. Y., Zhang X. X., Y. Xiong Y., and Li C. L. (2019) Petrography and mineralogy of Northwest Africa 8687. 50th Lunar and Planetary Science Conference, abstract no. 2372.