Lunar Meteorite: Northwest Africa 14900

Two views of a 52-g stone of Northwest Africa 14900. Photo credits: Matthew Stream
Three slices of NWA 14900. Photo credits: Matthew Stream
Two sides of a 3.8-g slice of NWA 14900. This piece has been highly affected by deposition of terrestrial evaporite minerals in fractures (melt veins?) in the rock. Photo credits: Matthew Stream

from The Meteoritical Bulletin, No. 111

Northwest Africa 14900 (NWA 14900)

(Northwestern Africa)
Purchased: 2022 March 13
Mass: 277g (8 pieces)

Lunar meteorite (fragmental breccia)

History: Purchased on March 13, 2022, by Matthew Stream from Aliyen Faida’llah in Morocco.

Physical Characteristics: Eight stones with slightly weathered fusion crust.

Petrography: (D. Sheikh, Cascadia) Sample represents a lunar polymict breccia composed of angular to sub-rounded mm-sized lithic and mineral clasts set within a glassy to fine-grained matrix containing regions of isolated melt pockets, shock melt veins, schlieren, and vesicles. Lithic clast lithologies include: anorthositic clasts, noritic clasts, troctolitic clasts, impact melt-rich clasts, basaltic clasts, and a ~2 mm dunite clast; mineral clasts include isolated grains of olivine (some displaying strong normal zoning), pyroxene (some displaying exsolution lamellae), and plagioclase (mix of fractured and smooth grains). Accessory phases include ilmenite, silica glass, Cr-rich spinel, troilite, and Fe-Ni metal.

Geochemistry: Olivine (Fa23.4±12.8, range Fa9.0-44.6, Fe/Mn=85±8, n=21), Low-Ca Pyroxene (Fs32.6±13.2Wo4.0±0.9, range Fs17.9-46.7Wo2.8-5.1, Fe/Mn=51±6, n=5), Pigeonite (Fs30.1±6.7Wo11.1±3.3, range Fs19.5-40.8Wo6.9-20.2, Fe/Mn=50±6, n=19), High-Ca Pyroxene (Fs19.3±4.9Wo38.0±3.7, range Fs8.6-25.0Wo33.3-43.2, Fe/Mn=45±4, n=9), Calcic Plagioclase (An95.5±1.6, range An90.2-97.1, n=22); Dunite clast [Olivine (Fa9.1±0.1, range Fa9.0-9.1, Mg#=91, Fe/Mn=80±10, n=8), Cr-rich spinel (Cr#=80.6±2.2, Mg#=53.8±4.5, n=3)].

Classification: Lunar (fragmental breccia) due to polymict nature of the sample.

Specimens: 20.2 g at Cascadia, main mass with Matthew Stream.

Randy Says…

I have not studied Northwest Africa 14900.

More Information

Meteoritical Bulletin Database

NWA 14900

References

Sheikh D., Ruzicka A. M., Hutson M.L., and Stream M. (2022) Dunite clast in lunar meteorite Northwest Africa (NWA) 14900: Mantle derived? 85th Annual Meeting of The Meteoritical Society, abstract no. 6077. 85th Annual Meeting of The Meteoritical Society, abstract no. 6077.

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