Lunar Meteorite: Northwest Africa 4936 clan

The NWA 4936 clan consists of paired stones NWA 4936, 5406, 6221, 6355, 6470, 6570, 7190, 7986, & 8181

Northwest Africa 4936 in the field. Photo credit: unknown
A photo alleged to be of NWA 4936 (but 5 stones?) that I found somewhere. Is this perhaps NWA 5406?
Two or three of the NWA 5406 stones. Photo credit: by Greg Hupé
Northwest Africa 6221. Photo credit: Philippe Thomas
Broken face of NWA 6570. What are the light-colored veins? Light-colored material occurs in the lab sample photo below, too. Photo credit: Ted Bunch
Interior of NWA 4936. Photo credit: Norbert Classen
Interior of NWA 5406. Photo credit: by Greg Hupé
Two photos of the interior of NWA 6221. Photo credits: Jean-Michel Masson (left) and Norbert Classen (right)
Interior of NWA 6355. Photo credit: Michael Blood
Thin section of NWA 6355. Field of view: 13 mm. Photo credit: Randy Korotev
Two sides of a slice of NWA 8181: Photo credit: Fabien Kuntz
Lab samples of some of the NWA 4936-clan stones: Photo credits: Randy Korotev

from The Meteoritical Bulletin, No. 95

Northwest Africa 4936 (NWA 4936)

Morocco
Find: September 2007
Mass: 179 g (2 pieces)

Achondrite (lunar, feldspathic breccia)

History: Purchased by an anonymous dealer in Siksou, Morocco, in September 2007.

Physical characteristics: Two dark gray, mostly very fine grained stones (72 g and 107 g) exhibiting hackly fracture and lacking obvious fusion crust. The interior is very dark gray, and resembles devitrified glass with dispersed small white clasts.

Petrography (A. Irving and S. Kuehner, UWS): Both specimens are composed of small mineral clasts and sparse lithic clasts in a very fine-grained matrix (which has heterogeneous glass). Mineral clasts include anorthitic plagioclase, pigeonite, augite, sparse olivine, Mg-bearing ilmenite, kamacitic metal and troilite. Lithic clasts include troctolite and probable mare basalt.

Geochemistry: Low-Ca pyroxene (Fs25.7Wo4.6, FeO/MnO = 56.8), pigeonite (Fs42.0Wo10.2, FeO/MnO = 63.1), olivine (Fa29.1, FeO/MnO = 75.2), plagioclase (An95.4–98.2Or0.2–0.0).

Bulk composition (R. Korotev, WUSL): FeO 6.1 wt%, Th 1.85 ppm.

Classification: Achondrite (lunar, feldspathic breccia).

Specimens: A total of 20.1 g, one polished thin section and one polished mount are on deposit at UWS; a further 20 g sample is on deposit at UAz. The main mass is held by Schrader.

from The Meteoritical Bulletin, No. 95

Northwest Africa 5406 (NWA 5406)

Morocco
Find: July 2008
Mass: 281 g (6 pieces)

Achondrite (lunar, feldspathic breccia)

History: Purchased by Greg Hupé in July 2008 from a dealer in Ouarzazate, Morocco, who reported that these stones were found in the same area as NWA 4936 near Siksou Mountain in southern Morocco.

Physical characteristics: Six, dark gray, mostly very fine-grained stones (total weight 281 g) with hackly fracture and lacking obvious fusion crust. The interior of each stone resembles devitrified glass with dispersed small white clasts.

Petrography: (A. Irving and S. Kuehner, UWS) All specimens are composed of small mineral clasts and sparse lithic clasts in a very fine-grained matrix (which has the texture of an impact melt with heterogeneous, “swirly” glass). Mineral clasts include anorthite, olivine, pigeonite, subcalcic augite, ilmenite, troilite, and irregular-shaped grains of kamacite.

Geochemistry: Pigeonite (Fs34.7Wo9.8, FeO/MnO = 59.9), augite (Fs55.8Wo26.4, FeO/MnO = 72.6), olivine (Fa25.7–27.0, FeO/MnO = 85.3–120), plagioclase (An96.2–97.2Or0.0).

Bulk composition : (R. Korotev, WUSL): FeO 5.8 wt%, Th 2.0 ppm, Sc 9.1 ppm, Ni 520 ppm, Sm 6.3 ppm.

Classification: Achondrite (lunar, feldspathic breccia). These stones have essentially the same distinctive textures, mineral compositions and bulk composition as NWA 4936, and are almost certainly paired with the latter stones.

Specimens: A total of 20.0 g of is on deposit at UWS. The main masses are held by Mr. G. M. Hupé.

from The Meteoritical Bulletin, No. 100

Northwest Africa 6221 (NWA 6221)

(Northwest Africa)
Purchased: Apr 2010
Mass: 109.4 g (1 piece)

Lunar meteorite (feldspathic breccia)

History: Purchased by P. Thomas in April 2010 from a dealer who reported that this stone was found near Geltat Zemmour.

Physical characteristics: One single stone, dark gray with white clasts.

Petrography: (A. Jambon, O. Boudouma, D. Badia) Small mineral clasts in a fine-grained matrix with some heterogeneous glass (impact melt glass). Contains plagioclase, pigeonite, augite, ilmenite, olivine, merrilite. Rare lithic clasts.

Geochemistry: Feldspar An96-89. Augite (Fs27-22Wo40-30, Fe/Mn=60). Olivine (Fa=12-29, Fe/Mn=60). Ilmenite with 6% MgO.

Bulk composition: (R. Korotev, WUSL): FeO 6.6 wt%, Sc 9.7 ppm, Ni 1120 ppm, Sm 5.7 ppm, Th 1.7 ppm.

Classification: Lunar (feldspathic breccia). Probably paired with NWA 4936 and NWA 5406.

from The Meteoritical Bulletin, No. 99

Northwest Africa 6355 (NWA 6355)

Morocco
Find: June 2009
Mass: 760 g (1 piece)

Achondrite (lunar, feldspathic breccia)

History: Found in southern Morocco in June 2009 and purchased by a consortium led by Matt Morgan from a Moroccan dealer in September 2010.

Physical characteristics: A single fine grained, brittle stone (760 g) with no obvious fusion crust. The interior is dark gray and resembles devitrified glass with dispersed small white clasts.

Petrography: Clast-laden vitric breccia consisting of fine grained mineral debris (mostly pyroxenes, olivine and anorthite) and sparse polycrystalline igneous clasts in a heterogeneous, “swirly” glassy matrix (in part vesicular). Mineral clasts include anorthitic plagioclase, low-Ca pyroxene, pigeonite, olivine, Mg-bearing ilmenite, kamacitic metal and troilite. Lithic clasts include microgabbronorite (composed of subcalcic augite, orthopyroxene, anorthite, Mg-bearing merrillite, silica polymorph, ilmenite, troilite and baddeleyite).

Geochemistry: Low-Ca pyroxene (Fs37.5-61.2Wo2.4-5.2, FeO/MnO = 65-88), pigeonite (Fs23.5-45.5Wo10.3-11.1, FeO/MnO = 48-76), subcalcic augite (Fs13.0Wo37.0, Fs17.6Wo30.1, Fs25.7Wo35.0, FeO/MnO = 55-59), augite (Fs11.3Wo41.8; FeO/MnO = 49), olivine (Fa29.5-33.9, FeO/MnO = 81-104), plagioclase (An91.6-96.1Or0.5-0.1).

Bulk composition: (R. Korotev, WUSL): FeO 5.8 wt%, La 13.0 ppm, Sm 6.1 ppm, Yb 3.95 ppm, Th 1.87 ppm.

Classification: Achondrite (lunar, feldspathic breccia). This stone is almost identical in texture, mineral compositions and bulk composition to NWA 4936, NWA 5406 and NWA 6221. It is possibly paired with those stones and is reportedly from the same find location.

Specimens: A total of 20.1 g of sample and one polished thin section are on deposit at UWS. The main mass is held jointly by Morgan, Abraham, Rose, Curtiss and an anonymous collector.

from The Meteoritical Bulletin, No. 99

Northwest Africa 6470 (NWA 6470)

Morocco
Find: 2009
Mass: 96 g (1 piece)

Lunar meteorite (feldspathic breccia)

History: Found in southern Morocco in 2009 and purchased by Jason Utas in April 2010 from a dealer in Ouarzazate, Morocco.

Physical characteristics: A fine-grained, dark gray, 96 g stone containing dispersed small white clasts.

Petrography: The specimen consists of small mineral clasts and sparse lithic clasts (some with ophitic textures) in a very fine grained, heterogeneous, partly glassy and in places vesicular matrix. Mineral clasts include anorthitic plagioclase, subcalcic augite, pigeonite, olivine, Mg-bearing ilmenite, kamacite, baddeleyite and troilite.

Geochemistry: Pigeonite (Fs23.6-26.9Wo16.2-7.0, FeO/MnO = 51-59), subcalcic augite (Fs21.0Wo36.1, FeO/MnO = 58), olivine (Fa21.9-29.3, FeO/MnO = 84-107), plagioclase (An91.6-95.2Or0.5-0.2).

Bulk composition: (R. Korotev, WUSL): FeO 5.6 wt%, La 11.1 ppm, Sm 5.0 ppm, Yb 3.24 ppm, Th 1.63 ppm.

Classification: Achondrite (lunar, feldspathic breccia). This stone is very similar in texture, mineral compositions and bulk composition to NWA 4936, NWA 5406, NWA 6221 and NWA 6355. It apparently is paired with those stones and is reportedly from the same find location.

Specimens: A total of 19.2 g of sample are on deposit at UWS. The main mass is held by Utas.

from The Meteoritical Bulletin, No. 99

Northwest Africa 6570 (NWA 6570)

Morocco
Find: 2010
Mass: 415 g (1 piece)

Lunar meteorite (feldspathic breccia)

History: Found in southern Morocco in 2010 and purchased from the finder by Adam Aaronson in December 2010.

Physical characteristics: A single fine grained, brittle stone (415 g) lacking fusion crust. The interior is dark gray with dispersed small white clasts.

Petrography: (A. Irving and S. Kuehner, UWS) Sparse felsic lithic clasts and mineral debris are enclosed within a dark, partly glassy and vesicular matrix. Mineral clasts include pigeonite, subcalcic augite, anorthitic plagioclase, olivine, ilmenite, kamacite and troilite.

Geochemistry: Olivine (Fa29.5-29.6; FeO/MnO = 92-120), pigeonite (Fs26.9-28.5Wo10.0-12.7, Fs43.7Wo5.6; FeO/MnO = 58-70), subcalcic augite (Fs31.6Wo29.6; FeO/MnO = 61), plagioclase (An91.5-95.4Or0.4-0.3).

Classification: Achondrite (lunar, feldspathic breccia). This specimen is texturally and mineralogically identical to NWA 4936, NWA 5406, NWA 6221, NWA 6355 and NWA 6470 found in the same area, and evidently is paired with those stones.

Specimens: A total of 20.0 g of sample is on deposit at UWS. The main mass is held by Aaronson.

from The Meteoritical Bulletin, No. 101

Northwest Africa 7190 (NWA 7190)

(Northwest Africa)
Found: 2011 Aug
Mass: 5.3 g (3 pieces)

Lunar meteorite (feldspathic breccia)

History: Three small stones found in southern Morocco in 2011 August were purchased from a Moroccan dealer by Norbert Classen.

Physical characteristics: Three very similar dark-colored stones (3.11 g, 1.87 g and 0.296 g) exhibiting small white clasts in a glassy matrix.

Petrography: (A. Irving and S. Kuehner, UWS) Vitric breccia composed of small mineral and lithic clasts in a very fine grained, heterogeneous glassy matrix. Minerals are anorthite, olivine, pigeonite, augite, ilmenite, troilite and minor kamacite.

Geochemistry: Olivine (Fa22.4-25.3, FeO/MnO = 90-97), orthopyroxene (Fs22.2Wo4.5, FeO/MnO = 54), pigeonite (Fs26.4Wo7.7, FeO/MnO = 67), augite (Fs11.2-11.3Wo43.8-46.2, FeO/MnO = 43-45).

Bulk composition: (R. Korotev, WUSL): mean values from INAA of subsamples are 6.0 wt.% FeO, 9.4 ppm Sc, 470 ppm Ni, 14.5 ppm La, 6.4 ppm Sm, 1.4 ppm Eu, 4.1 ppm Yb, 2.1 ppm Th.

Classification: Lunar (feldspathic breccia). Based on distinctive petrographic and bulk compositional attributes, these stones are likely paired with NWA 4936, NWA 5406, NWA 6221, NWA 6355, NWA 6470 and NWA 6570.

Specimens: 1.1 g is on deposit at UWB. Classen holds the main masses.

from The Meteoritical Bulletin, No. 102

Northwest Africa 7986 (NWA 7986)

(Northwest Africa)
Purchased: 2013 Jun
Mass: 12.2 g (1 piece)

Classification: Lunar meteorite (feldspathic breccia)

History: Purchased by Stefan Ralew in June 2013 from a Moroccan dealer at the Ensisheim Show.

Petrography: (A. Irving and S. Kuehner, UWS) Abundant partly devitrified, glassy matrix (with “swirly” texture) containing embedded small mineral and lithic clasts. Minerals are olivine, orthopyroxene, pigeonite, augite, anorthite, ilmenite, troilite and minor kamacite.

Geochemistry: Olivine (Fa33.4-34.5, FeO/MnO = 83-96), orthopyroxene (Fs34.7Wo2.3, FeO/MnO = 53), pigeonite (Fs25.8Wo6.3, FeO/MnO = 53), augite (Fs14.5Wo41.7; Fs33.5Wo39.5, FeO/MnO = 38-68), anorthite (An96.2-98.5Or0.1).

Bulk composition : (R. Korotev, WUSL): INAA of subsamples gave mean abundances of FeO 5.6 wt.%, and (in ppm) Sc 31, La 13.2, Sm 6.2, Eu 1.39, Yb 4.0, Th 1.9.

Classification: Lunar (feldspathic vitric breccia). On the basis of mineralogy, texture and bulk composition, this specimen is paired with NWA 4936, NWA 5406, NWA 6221, NWA 6355, NWA 6470, NWA 6570 and NWA 7190.

Specimens: 12.2 g are at UWB. The remainder is with Ralew.

from The Meteoritical Bulletin, No. 103

Northwest Africa 8181 (NWA 8181)

Morocco
Found: 2013
Mass: 18.2 g (1 piece)

Classification: Lunar meteorite (feldspathic breccia)

History: Purchased by Fabien Kuntz in June 2013 from a Moroccan dealer at the Ensisheim Show.

Petrography: (A. Irving and S. Kuehner, UWS) Very fine grained breccia composed of small mineral fragments and some very small metal grains irregularly distributed in a partly glassy and vesicular matrix. Minerals are olivine, orthopyroxene, pigeonite, subcalcic augite, anorthite, rutile, kamacite and minor barite.

Geochemistry: Olivine (Fa26.8-27.6; FeO/MnO = 94-99), orthopyroxene (Fs24.0-27.3Wo4.4-2.5; FeO/MnO = 53-60), subcalcic augite (Fs13.4Wo36.0; FeO/MnO = 47), ferropigeonite (Fs58.5Wo7.8; FeO/MnO = 64).

Bulk composition: (R. Korotev, WUSL) INAA of subsamples gave the following mean abundances (in wt.%) FeO 6.4, Na2O 0.53; (in ppm) Sc 10.0, Ni 530, La 16.5, Sm 7.35, Eu 1.54, Yb 4.82, Lu 0.671, Hf 5.6, Th 2.3.

Classification: Lunar (feldspathic vitric fragmental breccia). The distinctive texture and bulk composition of this specimen indicates that it is paired with NWA 4936, NWA 5406 and other stones from the Siksou Mountain area in southern Morocco.

Specimens: A 3.7 g specimen with one polished surface is at UWB. The main mass is held by Kuntz.

Randy Says…

The Northwest Africa 4936 clan is compositionally similar to soil from the Apollo 16 site and may have originate from near the Apollo 16 site. It is a fine examples of a glassy breccia.

More Information

Meteoritical Bulletin Database

NWA 4936 | 5406 | 6221 | 6355 | 6470 | 6570 | 7190 | 7986 | 8181


References

Korotev R. L. (2013) Siderophile elements in brecciated lunar meteorites44th Lunar and Planetary Science Conference, abstract no. 1028.

Korotev R. L. and Irving A. J. (2013) Keeping up with the lunar meteorites  201344th Lunar and Planetary Science Conference, abstract no. 1216.

Korotev R. L. and Irving A. J. (2014) Keeping up with the lunar meteorites  2014. 45th Lunar and Planetary Science Conference, abstract no. 1405.

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. (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 – 2008Lunar and Planetary Science XXXIX, abstract no. 1209.

Korotev R. L., Zeigler R. A., Irving A. J., and Bunch T. E. (2009) Keeping up with the Lunar Meteorites – 200940th Lunar and Planetary Science Conference, abstract no. 1137.

Korotev R. L, Zeigler R. A., Jolliff B. L., Irving A. J., and Bunch T. E. (2009) Compositional and lithological diversity among brecciated lunar meteorites of intermediate iron compositionMeteoritics & Planetary Science 44, 1287-1322.

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.

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 regolithScience Advances, 4, eaar4378

Rochette P., Gattacceca J., Ivanov A. V., Nazarov M. A., and Bezaeva N. S. (2010) Magnetic properties of lunar materials: Meteorites, Luna and Apollo returned samplesEarth and Planetary Science Letters 292, 383-391.

Xu X., Hui H., Chen W., Huang S., Neal C. R., and Xu X. (2020) Formation of lunar highlands anorthosites. Earth and Planetary Science Letters 536, 116138. doi.org/10.1016/j.epsl.2020.116138