Lunar Meteorite: Northwest Africa 2995 clan

from The Meteoritical Bulletin, No. 90

Northwest Africa 2995 (NWA 2995)

Algeria
Found: 2005
Mass: 538 g (1 piece)

Achondrite (lunar feldspathic breccia)

History: A 538 g, fully crusted and minimally weathered stone was purchased in Morocco by A. Aaronson in November 2005.

Petrography and Geochemistry: (T. Bunch and J. Wittke, NAU): The feldspathic fragmental breccia contains many highlands fine-grained lithologies including norite (orthopyroxene, Fs_26.4Wo₄, FeO/MnO = 66); olivine basalt (olivine, Fa_87.2 FeO/MnO = 95; plagioclase, An_84.7); subophitic basalt (Ca-pyroxene, Fs_25-48Wo_37.1-25.9; pigeonite, Fs_27.8-31.7Wo_15.4-9.3 FeO/MnO = 53; olivine Fa_36.3 FeO/MnO = 90; plagioclase, An₉₇); gabbro (olivine Fa_34.7 FeO/MnO = 95; pigeonite Fs_28.2Wo_8.9 FeO/MnO = 67; plagioclase An₉₄); KREEPy-like basalt (plagioclase, Ab₅₀Or_17.4; K-feldspar, Ab_14.3Or_83.6 in addition to silica, phosphate and Fe-rich pyroxenes); troctolite (Fa_30.8 FeO/MnO = 94; plagioclase An_94.7); granulitic impact melts (Fa₃₁; orthopyroxene, Fs_25.2Wo_3.4; plagioclase An₉₅); anorthosite (An_92.7-96.8); glassy impact melts, coarse-grained mineral fragments, and a 0.350 mm sized grain of meteoritic Ni, Fe metal (Ni = 6.3 Co = 1.0, both wt %). In addition, the assemblage appears to be characterized by large amounts of breccias within breccias: at least 4 generations of brecciation were observed in one cm-sized breccia clast. Numerous shock-induced melt veins are present along large breccia clast margins as well as isolated melt pockets within clasts. Interior weathering grade is very low, all glasses are fresh and no apparent terrestrial alteration veins were noted.

Classification: Achondrite (Lunar feldspathic breccia).

Specimens: A 21.2 g specimen is on deposit at NAU. Aaronson holds the main mass.

from The Meteoritical Bulletin, No. 95

Northwest Africa 2996 (NWA 2996)

Algeria
Find: 2006
Mass: 968 g (1 piece)

Achondrite (lunar, feldspathic breccia)

History and physical characteristics: A 968 g, partially crusted stone, was purchased in Morocco in November 2006 by Adam Aaronson and sold to a private collector in 2007. The weathered crust shows a color range of vermillion to dark brown to black. Several anorthositic clasts exposed on broken surfaces are as large as 3 cm.

Petrography (T. Bunch and J. Wittke, NAU): This feldspathic breccia has an extensive melt matrix with prominent entrainments of tiny bubbles. Lithologies include anorthosite, medium-grained gabbros, anorthositic norites and troctolites, in addition to mineral fragments, shocked clasts, and devitrified glassy clasts.

Mineral compositions: A medium-grained gabbroic clast contains plagioclase (An_92.1), olivine (Fa_32.4, FeO/MnO = 110), Ca pyroxene (Fs_22.4Wo_19.1), chromite (cr# = 61) and ilmenite (MgO = 5.3 wt%). Anorthositic norite low-Ca pyroxene is Fs_28.6Wo_3.1 (FeO/MnO = 64), troctolitic olivine is Fa_31.9, FeO/MnO = 104 and plagioclase clasts range from An_91.8 to An_97.4.

Bulk chemistry (R. Korotev, WUSL): TiO₂ = 0.68 wt%, Al₂O₃ = 20.7 wt%, FeO = 9.7 wt%, MgO = 8.0 wt%, Ni = 184 ppm, Sm = 4.6 ppm and Th = 1.6 ppm.

Classification: Lunar (feldspathic breccia).

Type specimen: A total of 20.3 g is on deposit at NAU. The main mass holder is anonymous.

from The Meteoritical Bulletin, No. 93

Northwest Africa 3190 (NWA 3190)

Northwest Africa
Find: 2006
Mass: 40.7 g (1piece)

Achondrite (lunar, mingled breccia)

History and physical characteristics: A. Aaronson purchased a 40.7 g partially crusted, complete stone in Rissani, Morocco in December 2006. The hand specimen exhibits an abundance of large (between 0.6 and 2.1 mm in dia.) anorthositic clasts. The weathered portion of the crust is pale vermillion to light brown, fresher crust is dark gray to black.

Petrography (T. Bunch and J. Wittke, NAU; A. Irving, UWS): This mingled breccia contains anorthositic lithologies that include anorthosite, anorthositic norites, gabbros and troctolites, in addition to variolitic and subophitic basalt clasts, breccia-within-breccia clasts, and an abundance of olivine and plagioclase fragments. Melt and fragmental matrices are heterogeneously distributed. The interior shows very low weathering effects.

Mineral compositions and geochemistry: Anorthositic norite orthopyroxene (Fs_28.5Wo_3.8; FeO/MnO = 65). Olivine gabbro contains olivine (Fa_26.2; FeO/MnO = 96), plagioclase (An_92.3), subcalcic pyroxene (Fs_21.6Wo_14.4; FeO/MnO = 48), and ilmenite with MgO = 6.5 wt%. Variolitic basalt has olivine (Fa_35.7; FeO/MnO = 103), pigeonite (Fs_24.6Wo_8.7) and plagioclase (An_95.5).

Bulk composition (R. Korotev, WUSL): FeO = 9.6 wt.%, Sm = 3.9 ppm, Th = 1.4 ppm, Ir = 6.5 ppb.

Classification: Achondrite (lunar, mingled breccia). Probably paired with NWA 2995, based on essentially identical bulk compositions.

Type specimen: A total of 8.8 g is on deposit at NAU. The main mass holder is anonymous.

from The Meteoritical Bulletin, No. 93

Northwest Africa 4503 (NWA 4503)

Northwest Africa
Find: 2007
Mass: 70 g (1  piece)

Achondrite (lunar, anorthositic breccia)

History and physical characteristics: A 70 g partially crusted stone was purchased in January 2007 by A. Aaronson and sold to a collector in July 2007. The fusion crust is dark to light brown and vermillion in translucent areas.

Petrography (T. Bunch, J. Wittke, NAU; A. Irving, UWS): This feldspathic melt breccia is dominated by very fine to medium-grained anorthositic lithologies that are typically enriched in olivine (anorthositic troctolites and gabbros) together with a large fraction of plagioclase, olivine, and exsolution-textured pyroxene fragments. Shock-melt clasts, K-, Ba-rich glasses, and fayalite-pyroxene-quartz igneous lithologies are also present. One granophyre clast shows a granophyric or micrographic texture of oriented quartz inclusions in alkali feldspar surrounded by shock-melted plagioclase. Most of the matrix is glassy and vesicular with included mineral fragments. Weathering effects are minimal.

Mineral compositions and geochemistry: Gabbro: olivine (Fa_34.8; FeO/MnO = 88), augite (Fs_14.6Wo_41.8; FeO/MnO = 42), plagioclase (An_97.6), chromite (cr# = 74). Troctolite: olivine (Fa_27.9; FeO/MnO = 83). Norite: orthopyroxene (Fs_24.8Wo_2.5; FeO/MnO = 55), augite (Fs_20.4Wo_38.9). Basaltic pyroxene fragments, host = Fs_46.9Wo_2.4, exsolution lamellae = Fs_19.8Wo_43.4. Granophyre K-feldspar (Or₇₂Ab_18.3).

Classification: Achondrite (lunar, anorthositic breccia).

Type specimen: A total of 14 g is on deposit at NAU. The main mass holder is anonymous.

from The Meteoritical Bulletin, No. 94

Northwest Africa 5151 (NWA 5151)

Algeria
Find: 2007
Mass: 289 g

Achondrite (lunar, feldspathic breccia)

History and physical characteristics: A 289 g stone was purchased in Rissani, Morocco in 2007. The exterior is reddish-brown to dark gray with minor, translucent residual fusion crust.

Petrography (J. Wittke and T. Bunch, NAU): The fragmental to melt matrix contains abundant breccia-within- breccia clasts together with typical highlands lithic components that mostly include anorthosites, noritic and troctolitic anorthosites, troctolites (olivine > 40 vol. %), gabbros, granulites, cataclastic breccias, shock melt clasts, in addition to mare basalt clasts and mineral fragments. Several small to mm-size metal globules are scattered throughout the matrix. Numerous dark brown, shock-melt veins are present along large clast margins. Interior weathering grade is very low with no apparent alteration veins.

Mineral compositions: Noritic anorthosite orthopyroxene is Fs_24.4Wo_3.8 (FeO/MnO = 60), plagioclase = An_94.2. Gabbro olivine is Fa_34.1 (FeO/MnO = 97), plagioclase is An_88.1, pigeonite is Fs_27.9Wo_9.2 (FeO/MnO = 55), chromite Cr/(Cr+Al) = 0.65 and Ni in metal is 5.8 to 6.6 wt %.

Bulk chemistry (R. Korotev, WUSL): Na₂O = 0.478 wt %; Sc = 16.7 ppm, Cr = 1440 ppm; FeO = 8.52 wt %; Ni = 171 ppm; Ba = 183 ppm; Th = 1.76 ppm.

Classification: Achondrite (lunar feldspathic breccia).

Type specimen: A total of 20.3 g is on deposit at NAU. The main mass holder is anonymous.

from The Meteoritical Bulletin, No. 94

Northwest Africa 5152 (NWA 5152)

Morocco
Find: 2006
Mass: 38 g (1 piece)

Achondrite (lunar, feldspathic breccia)

History and physical characteristics: A 38 g complete stone was purchased in Rissani Morocco in 2007. The dark gray fusion crust is mostly eroded away by wind ablation.

Petrography (J. Wittke and T. Bunch, NAU): The vesiculated melt matrix regolith breccia contains an abundance of typical anorthositic lithologies that include anorthosites, anorthositic norites, troctolitic anorthosites, granulites, devitrified shock melts, breccia-in-breccias, in addition to mare basalts and mineral fragments. Interior weathering effects are minimal.

Mineral compositions: Troctolite olivine, Fa_27.6 (FeO/MnO = 95); maskelynitized plagioclase fragments, An_91.2-97.6, norite orthopyroxene, Fs_25.5Wo_3.8 (FeO/MnO = 62); subophitic basalt pigeonite, Fs_29.7Wo_7.8.

Bulk chemistry (R. Korotev, WUSL): Sc = 16.8 ppm; Cr = 1460 ppm; FeO = 9.03 wt %; Ni = 210 ppm; Ir = 210 ppm.

Classification: Achondrite (lunar feldspathic breccia).

Type specimen: A total of 7.7 g is on deposit at NAU. The main mass holder is anonymous.

from The Meteoritical Bulletin, No. 99

Northwest Africa 6252  (NWA 6252)

Morocco
Find: 2010
Mass: 113 g (1 piece)

Lunar meteorite (feldspathic breccia)

History: A 113 g stone (NWA 6252), a 138 g stone (NWA 6554) and a 29.72 g stone (NWA 6555), all partially crusted and minimally weathered, were purchased in Morocco by A. Aaronson in 2010. These stone are from the same locality as NWA 2995 and its pairings.

Petrography: (T. Bunch and J. Wittke, NAU): Feldspathic breccia containing anorthositic, noritic, gabbros, olivine basalts, troctolites, granulitic breccias, and KREEPy-like lithologies. Breccia-in-breccia structures, impact melts, and veins are common. Moderately to heavily shocked, weathering grade is low.

Geochemistry: Anorthosite plagioclase (An₉₄), olivine basalt olivine (Fa_79.9, FeO/MnO = 97); norite orthopyroxene (Fs_25.8Wo_3.5, FeO/MnO = 60). Bulk composition (R. Korotev, WUSL): Na₂O 0.39 wt%, FeO 12.9 wt%, Sc 27 ppm, Sm 3.85 ppm, Eu 0.91 ppm, Th 1.40 ppm.

Classification: Achondrite (lunar, feldspathic breccia). Paired with NWA 2995.

Specimens: 20.3 g is on deposit at NAU. An anonymous collector holds the main mass.

from The Meteoritical Bulletin, No. 99

Northwest Africa 6554 (NWA 6554)

Morocco
Find: 2010
Mass: 138 g (1 piece)

Lunar meteorite (feldspathic breccia)

History: A 113 g stone (NWA 6252), a 138 g stone (NWA 6554) and a 29.72 g stone (NWA 6555), all partially crusted and minimally weathered, were purchased in Morocco by A. Aaronson in 2010. These stone are from the same locality as NWA 2995 and its pairings.

Petrography: (T. Bunch and J. Wittke, NAU): Same general description as given for NWA 2995 and 6252. A feldspathic breccia that contains anorthositic, noritic, gabbros, olivine basalts, troctolites, granulitic breccias, and KREEPy-like lithologies. Breccia-in-breccia structures, impact melts and veins are common. Moderately to heavily shocked, weathering grade is low.

Geochemistry: Anorthosite plagioclase An_92.4-95.6; troctolite olivine, Fa_32.2 (FeO/MnO = 96); olivine fragment, Fa_36.6 (FeO/MnO = 89). Chemistry (R. Korotev, WUSL): Na₂O = 0.44 wt% and FeO = 11.3 wt% and trace elements (ppm) Sc = 20, Sm = 4.11, Eu = 0.97, Th = 1.38.

Classification: Achondrite (Lunar, feldspathic breccia). Paired with NWA 2995.

Specimens: 20.7 g is on deposit at NAU. An anonymous collector holds the main mass.

from The Meteoritical Bulletin, No. 99

Northwest Africa 6555 (NWA 6555)

Morocco
Find: 2010
Mass: 29.72 g (1 piece)

Lunar meteorite (feldspathic breccia)

History: A 113 g stone (NWA 6252), a 138 g stone (NWA 6554) and a 29.72 g stone (NWA 6555), all partially crusted and minimally weathered, were purchased in Morocco by A. Aaronson in 2010. These stone are from the same locality as NWA 2995 and its pairings.

Petrography: (T. Bunch and J. Wittke, NAU): Same general description as given for NWA 2995 and 6252. A feldspathic breccia that contains anorthositic, noritic, gabbros, olivine basalts, troctolites, granulitic breccias, and KREEPy-like lithologies. Breccia-in-breccia structures, impact melts, and veins are common. Moderately to heavily shocked, wearhering grade is low.

Geochemistry:  Anorthosite plagioclase An_93-96.5; norite orthopyroxene Fe_24.3Wo_3.8; KREEPy-like basalt plagioclase An_35.6Or_19.3. Chemistry (R. Korotev, WUSL) Na₂O = 0.38 wt% and FeO = 12.2 wt%. Trace elements (ppm) Sc = 25, Sm = 3.83, Eu = 0.92, Th = 1.19.

Classification: Achondrite (Lunar, feldspathic breccia). Paired with NWA 2995

Specimens: 6.3 g is on deposit at NAU. An anonymous collector holds the main mass.

Randy Says…

This meteorite is compositionally and lithologically diverse, containing clasts of a large variety of rock types, from anorthosite to basalts as well as KREEP and mafic nonmare rocks. Some of these stones are reported to have been found in Algeria, but inside sources maintain that 2995 and 2996, at least, are really from Morocco. Thanks Aziz.

More Information

Meteoritical Bulletin Database

NWA 2995 | 2996 | 3190 | 4503 | 5151 | 5152 | 6252 | 6554 | 6555 |

References

Bunch T. E., Wittke J. H., and Korotev R. L. (2006) Petrology and composition of lunar feldspathic breccias NWA 2995, Dhofar 1180 and Dhofar 1428. 69th Annual Meeting of the Meteoritical Society, abstract no. 5254.

Carpenter P. K., Hahn T. M., Korotev R. L., Zeigler R. A., Jolliff B. L. (2017) Quantitative EPMA compositional mapping of NWA 2995: Characterization and petrologic interpretation of mafic clasts. Lunar and Planetary Science XLVIII, abstract no. 2607.

Gross J., Treiman A. H., and Mercer C. M. (2012) Sinking the lunar magma ocean: New evidence from meteorites and the return of serial magmatism. 43rd Lunar and Planetary Science Conference, abstract no. 2306.

Gross J., Treiman A. H., and Mercer C. (2012) Lunar feldspathic meteorites: constraints on the geology of the lunar farside highlands, and the origin of the lunar crust. Second Conference on the Lunar Highlands Crust, abstract no. 9003.

Gross J., Treiman A. H., and Mercer C. M. (2014) Lunar feldspathic meteorites: Constraints on the geology of the lunar highlands, and the origin of the lunar crust. Earth & Planetary Science Letters 388, 318-328.

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.

Hidaka H., Nishiizumi K., Caffee M., and Yoneda S. (2019) Samarium isotopic compositions of lunar meteorites. 82nd Annual Meeting of the Meteoritical Society, abstract no. 6279.

Joy K. H., Wang N., Tartèse R., Pernet-Fisher J. F., Liu Y., Lin Y. T., Darling J. R., Tar P., and Irving A. J. (2022) Is the age of the Moon’s South Pole Aitken Basin preserved in lunar meteorite Northwest Africa 2995? 85th Annual Meeting of The Meteoritical Society, abstract no. 6374.

Korotev R. L. and Irving A. J. (2013) Keeping up with the lunar meteorites – 2013. 44th Lunar and Planetary Science Conference, abstract no. 1216.

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

Korotev R. L. and Zeigler R. A. (2007) Keeping up with the lunar meteorites. Lunar and Planetary Science XXXVIII, abstract no. 1340.

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, 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 composition. Meteoritics & Planetary Science 44, 1287-1322.

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.

Macke R. J., Britt D. T., Kiefer W. S., Irving A. J., and Consolmagno G. J. (2011) Porosity, magnetic susceptibility and density of lunar meteorites. 74th Annual Meeting of the Meteoritical Society, abstract no. 5093.

Mercer C. N. and Treiman A. H. (2011) New lunar meteorite NWA 2996: a window into highland plutonic processes and KREEP metasomatism. 42nd Lunar and Planetary Science Conference, abstract no. 2111.

Mercer C. N., Treiman A. H., and Joy K. H. (2013) New lunar meteorite Northwest Africa 2996: A window into farside lithologies and petrogenesis. Meteoritics & Planetary Science 48, 289–315.

Xu L., Lin Y. T., Hofmann B. A., Gnos E., and Ouyang Z. Y. (2012) The origin of metal particles in lunar meteorites. 75th Annual Meeting of the Meteoritical Society, abstract no. 5247.

Wang N., Tartèse R., Joy K. H., Pernet-Fisher J. F., and Lin Y. T. (2019) Infrared spectroscopic characteristics of zircon in lunar meteorites Northwest Africa 2995 and 4485. 82nd Annual Meeting of the Meteoritical Society, abstract no. 6390.