Lunar Meteorite: Northwest Africa 11524

Endcut of Northwest Africa 11524. Photo credit: Live Auctioneers

from The Meteoritical Bulletin, No. 106

Northwest Africa 11524 (NWA 11524)

(northwestern Africa)
Purchased: 2017 June
Mass: 820 g (1 piece)

Lunar meteorite (basaltic breccia)

History: Purchased in June 2017 from Aziz Habibi in Erfoud, Morocco.

 Physical characteristics: Single stone consisting of approximately 50% green-brown, fine-grained basalt and 50% brecciated clasts of distinct basaltic lithologies set in a fine grained darker matrix. Contact between the basalt and the breccia is very sharp with markedly different fusion crust textures. The strikingly different rock textures on either side of the sharp contact give the appearance of two different meteorites fused together.

Petrography: (C. Agee, UNM) Microprobe examination was performed on polished slabs of both the basalt and breccia portions of the meteorite. The basalt portion consists of prismatic to acicular pigeonite and augite (50%), plumose plagioclase (25-35%), ubiquitous ilmenite (5-10%), and minor Fe-sulfide and Fe-metal. A significant shock melt vein was observed in the basalt portion. The composition and textures of the silicates and abundance of ilmenite in the basalt portion is typical of pyroxene-phyric, lunar mare basalt, hereafter Mare Basalt Lithology (MBL). The breccia consists of four distinct basalt lithologies (L1-L4) set in a fine-grained mix of pyroxene, plagioclase, and opaque fragments. L1 is an olivine-pigeonite basalt. L2 is an augite-pigeonite basalt with a strong pyroxene iron-enrichment trend. L3 is an olivine-pigeonite-augite basalt with a strong pyroxene iron-enrichment trend. L4 is an olivine-augite-pigeonite basalt with well-defined compositional separation between pigeonite and augite.

Geochemistry: (C. Agee, UNM) MBL: pigeonite Fs28.3±1.3Wo10.8±4.7, Fe/Mn=56±6, n=10; augite Fs24.1±1.5Wo31.5±3.5, Fe/Mn=56±6, TiO2=1.2±0.2, Cr2O3=1.2±0.2, Al2O3=3.4±0.4 (all wt%), n=4; ilmenite TiO2=52.4±0.6, FeO=46.3±0.3 (all wt%), Fe/Mn=146±11; plagioclase An86.9±1.3Ab12.4±1.2Or0.7±0.6, n=7. Shock melt vein (proxy for bulk composition) SiO2=45.7±1.1, TiO2=3.2±0.6, Cr2O3=0.4±0.2, Al2O3=11.1±2.9, MgO=6.9±1.9, FeO=18.9±1.1, MnO=0.25±0.02, CaO=11.3±0.5, NiO=0.02±0.01, Na2O=0.36±0.14, K2O=0.19±0.10 (all wt%), n=4. L1: olivine Fa30.2±0.1; Fe/Mn=92±7; pigeonite Fs22.6±2.4Wo15.2±5.4, Fe/Mn=50±2, n=4; plagioclase An87.9±0.9Ab10.1±0.3Or1.9±0.6, n=3. L2: pigeonite Fs42.7±10.7Wo15.4±4.6, Fe/Mn=60±10, n=7; augite Fs38.5±24.5Wo29.1±4.2, Fe/Mn=58±11, n=3; plagioclase An93.6±1.4Ab6.2±1.4Or0.3±0.1, n=4. L3: olivine Fa39.4±6.4; Fe/Mn=96±6; pigeonite Fs34.4±12.3Wo12.8±2.6, Fe/Mn=58±5, n=2; augite Fs41.7±13.8Wo27.9±4.0, Fe/Mn=64±9, n=8; plagioclase An92.9±1.9Ab6.5±1.5Or0.6±0.4, n=4. L4: olivine Fa36.4±1.3; Fe/Mn=97±8; pigeonite Fs25.8±1.7Wo13.8±3.7, Fe/Mn=53±4, n=2; augite Fs16.2±0.6Wo34.0±2.9, Fe/Mn=47±9, n=7; plagioclase An89.2±2.8Ab9.7±2.5Or1.1±0.3, n=4.

Classification: Lunar, basaltic breccia

Specimens: 25.1 g on deposit at UNM, DPitt holds the main mass.

Randy Says…

I have not studied Northwest Africa 11524. It is probably a new one; no other basaltic NWA breccia has 3% TiO2 and 11% Al2O3.

More Information

Meteoritical Bulletin Database

NWA 11524