Lunar Meteorite: Northwest Africa 3163 clan

from The Meteoritical Bulletin, No. 90

Northwest Africa 3163 (NWA 3163)

Mauritania or Algeria
Find: 2005 August
Mass: 1634 g (1 piece)

Achondrite (lunar, feldspathic granulitic impactite)

History: In August 2005, G. Hupé purchased a 1634 g stone from a Moroccan dealer in Ouarzazate.

Petrography and Geochemistry: (A. Irving and S. Kuehner, UWS) The exterior is almost completely coated by a thin, transparent, greenish fusion crust. The pale gray interior has multiple shock fractures (with very minor calcite coatings) and some thin glass veins. Poikiloblastic recrystallized breccia, with larger grains of plagioclase (~70 vol%) enclosing much smaller grains (less than 100 µm across) of pyroxenes (~20 vol%), olivine (~10 vol%), and accessory Ti-chromite (Cr/(Cr+Al) = 0.714–0.736; Mg/(Mg+Fe) = 0.121– 0.143; TiO₂ = 9.1–18.4 wt%), ilmenite, troilite, and metal (Ni = ~15 wt%). Anorthitic plagioclase (An_97.4-98.2) has been converted by shock almost entirely to maskelynite (although domains of birefringent, less-shocked feldspar remain). Pigeonitic pyroxene grains have very fine-scale exsolution lamellae of augite (Fs_14.5-16.1 Wo_40.2-40.5; FeO/MnO = 41.7– 43.8) within orthopyroxene Fs_32.0-33.9 Wo_4.4-5.8; FeO/MnO = 55.5–61.2). Olivine (Fa_38.0-40.9; FeO/MnO = 91.7–110).

Classification: Achondrite (lunar, feldspathic granulitic impactite).

Specimens: A 20.1 g type specimen and one polished thin section are on deposit at UWS. G. Hupé holds the main mass.

from The Meteoritical Bulletin, No. 94

Northwest Africa 4483  (NWA 4483)

Algeria
Find: 2006 July
Mass: 208 g (12 pieces)

Achondrite (lunar, granulitic breccia)

History: Purchased by Stefan Ralew in July 2006 from a dealer in Erfoud, Morocco.

Physical characteristics: Twelve broken fragments of very fine-grained, pale grey rock with a combined weight of 208 g.

Petrography (A. Irving and S. Kuehner, UWS): Fine grained recrystallized breccia composed of larger plagioclase grains (converted mainly to maskelynite) poikilitically enclosing very small grains (mostly 30-80 microns) of low-Ca pyroxene (some with very fine augite exsolution lamellae), olivine, Ti-chromite, ilmenite, troilite and metal.

Geochemistry: Olivine (Fa_30.9-60.8, FeO/MnO = 88.1- 106), plagioclase (An9_6.2-98Or_<0.1), orthopyroxene(Fs_14.3Wo_2.0, FeO/MnO = 52.6), pigeonite (Fs_{36.4- 75.1}Wo_6.3-13.5, FeO/MnO = 62.9-66.5).

Classification: Achondrite (lunar, granulitic breccia). Possibly paired with Northwest Africa 3163 (Irving et al., 2006).

Specimens: A total of 20 g and one polished mount are on deposit at UWS. Ralew holds the main mass.

from The Meteoritical Bulletin, No. 91

Northwest Africa 4881  (NWA 4881)

Mauritania or Algeria
Find: 2005
Mass: 606 g (1 piece)

Achondrite (lunar, granulitic breccia)

History: Found in 2005 and purchased by Stefan Ralew in January 2007 from a dealer in Ouarzazate, Morocco.

Physical characteristics: A single, broken, irregular conical stone (606 g) partially covered by translucent, pale greenish fusion crust and with a pale grey-brown interior.

Petrography: (A. Irving and S. Kuehner, UWS) Fine grained recrystallized breccia composed of larger plagioclase grains (converted partially to maskelynite) poikilitically enclosing very small grains (mostly 30-80 microns) of low-Ca pyroxenes, olivine, Ti-chromite, ilmenite, troilite and metal.

Mineral compositions and geochemistry: Olivine (Fa_40.4-58.8, FeO/MnO = 91-100), plagioclase (An_96.1-98Or_<0.1), pigeonite (Fs_32.0-64.5Wo_9.5-13.1, FeO/MnO = 51.1-62).

Classification: Achondrite (lunar, granulitic breccia). This stone is paired with Northwest Africa 3163 (Irving et al., 2006) and Northwest Africa 4483; in combination these specimens evidently represent naturally broken pieces from a crusted lunar meteorite weighing at least 2448 g.

Specimens: A total of 20 g of sample and one polished mount are on deposit at UWS. Ralew holds the main mass.

from The Meteoritical Bulletin, No. 99

Northwest Africa 6275  (NWA 6275)

Mauritania
Purchased: 2010 February
Mass: 1.31 g (5 pieces)

Lunar meteorite (feldspathic breccia)

History: Reportedly found in Mauritania and purchased by Norbert Classen in February 2010 from a dealer in Agadir, Morocco.

Physical characteristics: Five small pale gray stones totaling 1.3 g.

Petrography (A. Irving and S. Kuehner, UWS) Fine grained recrystallized breccia composed of larger plagioclase grains poikilitically enclosing small grains (<100 µm) of pigeonite, subcalcic augite, olivine, Ti-chromite, ilmenite, troilite and metal.

Geochemistry: Olivine (Fa_41.9-42.3, FeO/MnO = 81-89), plagioclase (An_92.2-96.7Or_0.3-<0.1), pigeonite (Fs_31.0-32.0Wo11.5-14.1, FeO/MnO = 62-68), subcalcic augite (Fs19.3-19.6Wo_37.1-36.9, FeO/MnO = 50-62).

Bulk composition: (R. Korotev, WUSL): FeO 3.3 wt%, Sc 7.1 ppm, Sm 0.40 ppm, Th 0.11 ppm.

Classification: Achondrite (lunar, granulitic feldspathic breccia). This material has essentially the same texture, mineralogy and mineral compositions as NWA 3163, NWA 4483 and NWA 4881 (which are different portions of one naturally broken mass). The bulk composition of NWA 6275 is somewhat similar to that of the other specimens, although a little more felsic. Yet given the fine scale mineralogical heterogeneity in all of these specimens, a pairing relationship among all of them seems likely.

Specimens: A 0.3 g polished piece is on deposit at UWS. Mr. N. Classen holds the remaining material (except for one stone consumed in bulk analyses).

Randy Says…

NWA 3163 is one of the few granulitic breccias – a metamorphic rock. This is why clasts are not so evident on sawn faces even though it is a breccia.

More Information

Meteoritical Bulletin Database

NWA 3163 | 4483 | 4881 | 6275

References

Dammeier R. , Moser D., and Osinski G. R. (2010) Understanding lunar granulites through a terrestrial analogue study. Goldschmidt Conference Abstracts 2010, A205.

Fernandes V. A., Irving A. J., Kuehner S. M., Gellissen M., Korotev R. L., and Bandfield J. L. (2009) Petrology, bulk composition, Ar-Ar age and IR emission spectrum of lunar granulite Northwest Africa 4881. 40th Lunar and Planetary Science Conference, abstract no. 2009.

Hudgins J. A. and Spray J. G. (2009) Lunar granulitic breccias: Differences between Apollo and meteorite samples. 72nd Annual Meeting of the Meteoritical Society, abstract no. 5157.

Hudgins J. A., Kelley S. P., Korotev R. L., and Spray J. G. (2011) Mineralogy, geochemistry, and ⁴⁰Ar – ³⁹Ar geochronology of lunar granulitic breccia Northwest Africa 3163 and paired stones: Comparisons with Apollo samples. Geochimica et Cosmochimica Acta 75, 2865-2881.

Hudgins J. A. Spray J. G, and Hawkes C. D. (2011) Element diffusion rates in lunar granulitic breccias: Evidence for contact metamorphism on the Moon. American Mineralogist 96, 1673-1685.

Irving A. J., Kuehner S. M., Korotev R. L., Rumble D. III, and Hupé G. M. (2006) Mafic granulitic impactite NWA 3163: A unique meteorite from the deep lunar crust. Lunar and Planetary Science XXXVII, abstract no. 1365.

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. (2006) New geochemical data for a some poorly characterized lunar meteorites. Lunar and Planetary Science XXVII, abstract no. 1404.

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., Zeigler R. A., Irving A. J., and Bunch T. E. (2009) Keeping up with the Lunar Meteorites – 2009. 40th Lunar and Planetary Science Conference, abstract no. 1137.

Korotev R. L., Irving A. J., and Bunch T. E. (2012) Keeping Up With the Lunar Meteorites – 2012. 43rd Lunar and Planetary Science Conference, abstract no. 1152.

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.

Lehman Franco K. M., Wilson B. J. K., Tait K. T., and Economos R. (2002) Disturbance of Pb-Pb ages of apatites within lunar granulite Northwest Africa 3163 associated with variations in microtextural domains. 53rd Lunar and Planetary Science Conference, abstract no. 2619.

McLeod C. L., Brandon A. D., Lapen T. J., Shafer J. T., Peslier A. H., and Irving A. J. (2013) The petrology and geochemistry of feldspathic granulitic breccia NWA 3163: Implications for the lunar crust. 44th Lunar and Planetary Science Conference, abstract no. 2003.

McLeod C. L., Brandon A. D., Fernandes V. A., Peslier A. H., Fritz J., Lapen T. J., Shafer J. T., Butcher A. R., and Irving A. J. (2016) Constraints on formation and evolution of the lunar crust from feldspathic granulitic breccias NWA 3163 and 4881. Geochimica et Cosmochimica Acta 187, 350-374.

Nishiizumi K. and Caffee M. W. (2006) Constraining the number of lunar and martian meteorite falls. 69th Annual Meeting of the Meteoritical Society, abstract no. 5368.

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 samples. Earth and Planetary Science Letters 292, 383-391.

Shafer J. T., Hall C., Lapen T. J., and Brandon A. D. (2010) Northwest Africa 3163: A window into the deep lunar crust? Geochimica et Cosmochimica Acta 74 Supplement, A939.

Shafer J. T., Brandon A. D., Lapen T. J., Peslier A. H., Irving A. J. (2011) Trace element geochemistry of a lunar granulite: Evidence from Northwest Africa 3163. 42nd Lunar and Planetary Science Conference, abstract no. 1508.