Lunar Meteorite: Northwest Africa 10509 clan

northwestern Africa

The Northwest Africa 10509 clan consists of NWA 10509, NWA 10798, NWA 10986, La’gad 003, and 2 unnamed possible pairs

Two views of NWA 10509 (660 g) Photo credit: Weibiao Hsu

Two views of NWA 10798 (319 g). Photo credit: Ben Hoefnagels

Two views of one of the NWA 10986 pieces. Photo credit: Heritage Auctions

Lab sample of NWA 10509. Photo credit: Randy Korotev

Lab sample of NWA 10798. Photo credit: Randy Korotev

Lab sample of L’gad 003. Photo credit: Randy Korotev

More lab samples of L’gad 003. Photo credit: Randy Korotev

Lab sample of NWA 10986, Photo credit: Sarah Roberts

from The Meteoritical Bulletin, No. 105

Northwest Africa 10509 (NWA 10509)

Morocco
Find: 2014
Mass: 660 g (1 piece)

Lunar meteorite (anorthosite)

History: Purchased by Ke Zuokai in Dec. 2015 from a Moroccan dealer.

Physical characteristics: A single, irregularly shaped stone lacking fusion crust. Small white clasts are visible in a pale, finer-grained matrix.

Petrography: (W. Hsu, PMO) Fragments of plagioclase (100 μm to sub-mm) set in recrystallized matrix of fine-grained (~ 20 μm) olivine, pigeonite, and plagioclase. Olivine fragments are less abundant.

Geochemistry: Plagioclase (An86.5-98.0Ab3-13Or0-1, average: An94±4Ab5±4) (n=8), olivine (Fa22-41, FeO/MnO = 83-98), pigeonite (Fs17-59Wo3-22, FeO/MnO = 45-61).

Classification: Lunar, anorthositic breccia.

Specimens: 20 g at PMO.

from The Meteoritical Bulletin, No. 105

Northwest Africa 10798 (NWA 10798)

(Northwestern Africa)
Purchase: 2016 May, August, September
Mass: 318.6 g (many pieces)

Lunar meteorite (feldspathic breccia)

History: A stone was purchased by Ben Hoefnagels in May 2016 from a dealer in Ouarzazate, Morocco. Subsequently additional material was found at the same find site by the same nomad, and purchased by Ben Hoefnagels in August and September 2016.

Physical characteristics: Six larger stones (110.9, 82.1, 32.6, 30.8, 16.9, and 15.4 g) plus many smaller stones (total 29.9 g). All stones have the same distinctive appearance, lacking fusion crust but mostly coated by orange weathering products. The fresh interior exhibits whitish clasts in a light-gray matrix with visible vesicles.

Petrography: (A. Irving and S. Kuehner, UWS) Breccia consisting of rounded to angular gabbroic anorthositic clasts, related crystalline debris, rare mare basalt clasts and very fine grained devitrified glassy clasts in a fine grained, partly vesicular matrix composed of quenchiform crystals plus glass. Minerals are anorthite, exsolved pigeonite, olivine (some forsteritic), augite, subcalcic augite, magnesian orthopyroxene, unexsolved pigeonite, ilmenite, Ti-chromite, troilite, minor primary Ba-Ca-K feldspar and secondary barite.

Geochemistry: Olivine (Fa6.0, FeO/MnO = 129; Fa53.7-60.6, FeO/MnO = 86-95; N = 4), pigeonite (Fs29.2Wo7.7, FeO/MnO = 47; Fs45.3Wo5.6, FeO/MnO = 53; N = 2), augite (Fs18.1Wo39.3, FeO/MnO = 41), orthopyroxene host (Fs59.4Wo2.1, FeO/MnO = 62), clinopyroxene exsolution lamella (Fs25.3Wo41.0, FeO/MnO = 45), plagioclase (An96.2-97.3Or0, N = 2).

Classification: Lunar (feldspathic regolith breccia).

Specimens: 20.66 g including one polished thin section at UWB; remainder with Mr. B. Hoefnagels.

from The Meteoritical Bulletin, No. 105

Northwest Africa 10986 (NWA 10986)

Grarat Zawi, Western Sahara
Find: 15 November 2015
Mass: 108.2 g (several pieces)

Classification: Lunar meteorite

Physical characteristics:Total mass of the meteorite = 108.2 g and comprises several pieces, the larger weighing 80.5 g.

Petrography: (S. Roberts, UTenn) A highland impact-melt breccia with an unusually large amount of impact-generated glass. Displays multiple generations of melting and breccia-in-breccia formation. Brown to black devitrified glass swirls encompass heavily fragmented lithic clasts and mineral fragments. Lithic clasts represent 40% of the meteorite and have been partially to completely consumed during multiple impact and melting events. Clasts are heavily brecciated and range in size from 1.4 to 0.1 mm long. The clasts are plagioclase-rich with pyroxenes, olivines, spinel, and ilmenite in ophitic to poikilitic textures. Large broken plagioclase grains and small olivines and pyroxenes are found within the matrix. Lithic types range from FANs to Hi-Mg Suite rocks.

Geochemistry: Mineral compositions and geochemistry: Analyses were obtained from both lithic clasts and lose mineral fragments from within the breccia matrix. Plagioclase compositions average An95.7±1.7 (N=43). Average pyroxene composition is Fs36.6±13.3Wo16.4±8.2 (N=73). Average olivine composition is Fs30.9±12.9 (N=50). Fe/Mn ratios for pyroxenes are 58.7±8.1 (N= 73) and olivines are 98.8±8.7 (N=50).

Specimens: 22 g at University of Tennessee

from The Meteoritical Bulletin, No. 109

La’gad 003

Saguia el Hamra, Western Sahara
Find: 2015
Mass: 27.249 kg (many pieces)

Lunar Meteorite (feldspathic breccia)

History: Found in 2015 by nomads on a small hill named Grarat-Zawi, and purchased by Darryl Pitt on behalf of MMGM from Mauritanian dealers in the period August-October 2015.

Physical characteristics: A single, very large stone (27.249 kg) found as a group of many pieces which fit together (but with several missing pieces). The specimen lacks fusion crust, but individual pieces have thin coatings of light-brown weathering products. Fresh interiors exhibit angular, whitish clasts within a dark-gray matrix.

Petrography: (A. Irving and S. Kuehner, UWS) Breccia composed predominantly of mineral clasts plus rare glass clasts and basalt clasts in a finer grained, partly vesicular matrix. Minerals are anorthite, olivine, pigeonite, orthopyroxene, exsolved pigeonite, subcalcic augite, Al-rich chromite, ilmenite and baddeleyite. Minor amounts of secondary calcite and barite are present.

Geochemistry: Olivine (Fa30.0-52.6, FeO/MnO = 84-110, N = 4), pigeonite (Fs28.2-38.2Wo9.8-14.7, FeO/MnO = 50-54, N = 3), orthopyroxene (Fs19.3Wo4.5, FeO/MnO = 57), subcalcic augite (Fs49.6Wo28.3, FeO/MnO = 59), plagioclase (An95.2-97.1Or0.1-0.2, N = 3).

Bulk composition: (R. Korotev, WUSL) INAA of 10 subsamples from different portions of the reassmbled mass gave the following mean abundances: (in wt.%) FeO 5.95±0.88, Na2O 0.34±0.02, BaO 0.51; (in ppm) Sc 13.6±2.6, Cr 930±210, Ni 140±160, La 2.3±0.6, Sm 1.0±0.2, Eu 0.75±0.06, Yb 0.85±0.14, Lu 0.13±0.02, Hf 0.65±0.13, Th 0.37±0.11.

Classification: Lunar (feldspathic regolith breccia). Based on closely similar bulk chemical compositional data (determined by Dr. R. Korotev at WUSL utilizing the same INAA methods), it is likely that the NWA 10509 stone and the material classified as NWA 10798 are paired portions of the same disaggregated meteorite. Another lunar feldspathic meteorite from a different location in the same dense collection area received the name La’gad, but analyses by Dr. Korotev demonstrate that the La’gad stones differ from the material described here, especially in having much higher (by a factor of 6) abundances of Th and other lithophile elements.

Specimens: 33.21 g including two polished endcuts at UWB; main mass at MMGM.

Randy Says…

The NWA 10509 clan is a basalt-bearing (minor) feldspathic lunar meteorite. These stones are compositionally heterogeneous and together are, along with NWA 6888 and the NWA 10495 clan, the most contaminated with terrestrial barium among lunar meteorites.

More Information

Meteoritical Bulletin Database

NWA 10509 | 10798 | 10986 | La’gad 003

References

Korotev R. L. and Irving A. J. (2017) Still not keeping up with the lunar meteorites – 2017Lunar 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. 

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

Roberts S. E., Jean M. M., Sueilem M. B., and Taylor L. A. (2017) Northwest Africa 10986: An impact-melt breccia from the lunar highlandsLunar and Planetary Science XLVIII, abstract no. 2220.

Roberts S. E., McCanta M. C., Jean M. M., and Taylor L. A. (2017) Northwest Africa 10986: A complex lunar highlands breccia. 80th Annual Meeting of the Meteoritical Society, abstract no. 6110.

Roberts S. E., McCanta M. C., Jean M. M., and Taylor L. A. (2019) New lunar meteorite NWA 10986: A mingled impact melt breccia from the highlands—A complete cross section of the lunar crust. Meteoritics & Planetary Science 54, 3018–3035.

Lunar Meteorites | List of Lunar meteorites