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Lunar Meteorite

Northwest Africa 5744, 8599, 8687, 10140,
10178, 10318, 10401, & unnamed stones
(paired stones)

northwestern Africa

 

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Weathered surface of Northwest Africa 5744; there is no fusion crust.

(photo credit: Ted Bunch)

 

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Sawn slice of NWA 5744. Click on image for enlargement.

(photo credit: Randy Korotev)

 

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Sawn face of Northwest Africa 8599

(photo credit: Fabien Kuntz)

 

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Sawn faces of NWA 8687. Click on image for enlargement.

(photo credit: Gary Fujihara)

 

 

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lm_nwa8687_2633s.jpg

Two sides of a slice of NWA 8687. Click on image for enlargement. Thanks to Fujihara for the sample.

(photo credit: Randy Korotev)

 

 

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Sawn face of NWA 10140

(photo credit: Larry Atkins)

 

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310-g stone of NWA 10178. Click on image for enlargement.

(photo credit: Darryl Pitt)

 

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A slice of NWA 10178 with translucent green glass veins.

(photo credit: Barbra Barrett / MMGM)

 

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Lab sample of NWA 8599

(photo credit: Randy Korotev)

 

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Lab sample of NWA 10178

(photo credit: Randy Korotev)

 

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Lab sample of NWA 10318. Thanks to Stephan Decker for the sample.

(photo credit: Randy Korotev)

 

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Photomicrograph of a thin section of NWA 10318 showing the granulitic texture.

(photo credit: Addi Bischoff)

 

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Sawn slice of NWA 10401. Thanks to Steve Arnold for the sample.

(photo credit: Randy Korotev)

 

 

lm_nwa_unn55_8051.jpg

unnamed 55

(photo credit: Rachid Chaoui)

 

from The Meteoritical Bulletin, No. 96, Meteoritics & Planetary Science 45, 13551397 (2009)

Northwest Africa 5744

Mali
Find: 2009 February
Mass: 170 g

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 m) with fine-grained (<50 m) olivine, pigeonite, orthopyroxene, and accessory Ti-chromite and Ni-bearing troilite.

Geochemistry: Plagioclase (An97.9Or0.1), olivine (Fa20.7, FeO/MnO = 76.994.5), pigeonite (Fs16.6Wo9.7, 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

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

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 (Fa23.3-23.5, FeO/MnO = 81-83), low-Ca pyroxene (Fs18.9-19.6Wo5.2-4.7; FeO/MnO = 53-58), high-Ca pyroxene (Fs9.8Wo40.6, FeO/MnO = 59), plagioclase (An97.0-97.1Or0.1). 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

(Mauritania)
Found: 2014 April
Mass: 563 g

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 m, scattered larger plagioclase and olivine 200-500 m, some poikioblastic plagioclase with fine-grained olivines and pyroxenes. Shock melt veins are found throughout. Scatterered Ti-chromite grains up to 100 m, other accessory phases include FeNi-metal, troilite, ilmenite, and apatite. Minor pigeonite and augite present.

Geochemistry: (C. Agee and N. Muttik, UNM). olivine Fa21.72.2, Fe/Mn=885, n=24; low-Ca pyroxene Fs19.62.3Wo3.51.4, Fe/Mn=543, n=11; pigeonite Fs16.8Wo19.1, Fe/Mn=41, n=1; augite Fs11.3Wo37.2, Fe/Mn=41, n=1; plagioclase An96.70.8Ab3.10.8Or0.20.0, n=7; Shock melt (20 m defocused electron beam, proxy for bulk meteorite composition): SiO2=43.010.66, TiO2=0.140.03, Al2O3= 23.852.94, Cr2O3=0.150.05, MgO=12.113.05, FeO=5.201.17, MnO=0.060.01, CaO=13.481.32, NiO=0.020.02, Na2O=0.250.05, K2O=0.030.00 (all wt%), Fe/Mn=8429, Mg#=80.50.8, 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

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

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 Fa23.42.8, Fe/Mn=904, n=11; low Ca pyroxene Fs20.51.1Wo3.70.9, Fe/Mn=566, n=9; plagioclase An97.11.0Ab2.71.0Or0.20.0, n=5; Shock melt (20 m defocused electron beam, proxy for bulk meteorite composition): SiO2=42.10.3, TiO2=0.130.04, Al2O3=27.33.1, Cr2O3=0.110.04, MgO=7.82.7, FeO=4.41.5, MnO=0.050.02, CaO=15.41.4, NiO=0.000.00, Na2O=0.270.03, K2O=0.000.00 (all wt%), Fe/Mn=8935, Mg#=75.90.8, MgO+FeO=12.14.2 (wt%), n=12.

Classification: Lunar (troctolitic anorthosite) based on Stffler 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

(Northwest Africa)
Purchased: 2015
Mass: 1279.3 g

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 (Fa22.7-23.0, FeO/MnO = 87-91, N = 3), orthopyroxene (Fs18.7-18.8Wo2.9-3.2, FeO/MnO = 47-61, N = 2), maskelynite (An95.9-97.4Or0, 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

Morocco
Purchased: 22 Apr 2015
Mass: 11.0 g

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 Fa26.40.6, Fe/Mn=97, n=11; low-Ca-pyroxene Fs21.80.7Wo5.02.0, Fe/Mn=54, n=11; plagioclase An97.10.6, range: An96.0-98.2 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

(Northwest Africa)
Purchased: 2015
Mass: 354 g

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 Fa18.62 (N=180), Fe/Mn=88.18.3; Orthopyroxene: Fs15.52WoEn, Fe/Mn=49.36 (N=48); Clinopyroxene: Fs9.01.4Wo41.37.9 En49.76.8, Fe/Mn=37.24 (N = 20); Plagioclase An96.60.3Ab2.90.6Or0.10.05 (N=254). The shock melt vein (defocused electron beam as proxy for bulk composition) has an average composition of: Na2O = 0.270.1, MgO = 9.70.3, SiO2 = 450.8, Al2O3 = 260.6, P2O5 = 0.020.04, K2O = 0.010.01, CaO = 156, TiO2 = 0.120.03, MnO = 0.060.04, FeO = 4.10.3, BaO = 0.010.03 Cr2O3 = 0.130.03, NiO = 0.020.02, 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.

 

Randy Says

I have chemically analyzed 9 of these stones. They overlap in composition and together are different from any other lunar meteorite. I have not analyzed 10140 but I assume that it is a member of the pair group on the basis of the petrographic descriptions, which are distinct, and photographs of the stones.

 

More Information

Meteoritical Bulletin Database

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

References

Gross J., Prissel1 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. 48th Lunar and Planetary Science Conference, abstract no. 2589.

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.

Korotev R. L. (2013) Siderophile elements in brecciated lunar meteorites. In 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. 48th Lunar and Planetary Science Conference, abstract no. 1498.

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. In Lunar and Planetary Science XLI, abstract no. 1552.

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. In Lunar and Planetary Science XLIII, abstract no. 2559.

 

 

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Prepared by
: Randy L. Korotev

Department of Earth and Planetary Sciences
Washington University in St. Louis

Please don't contact me about the meteorite you think you've found until you read this and this.


e-mail
korotev@wustl.edu

Last revised: 5-February-2017