Northwest Africa 10203 (NWA 10203)

(Northwest Africa)

Purchased: 2015

Classification: Lunar meteorite

History: Purchased by Aziz Habibi in 2015; reportedly found in near the border between Mauritania and Mali.

Physical characteristics: Twenty-seven identically appearing pieces reportedly found together. Irregular exterior, no fusion crust. A saw cut reveals a polymict breccia with numerous fragmental light and dark clasts.

Petrography: (C. Agee, UNM) This polymict breccia has at least four distinct lithologies. 1) unbrecciated olivine gabbro with zoned clinopyroxene (~75%), acicular, plumose plagioclase (~15%), olivine (~5%), and minor titanomagnetite; 2) fragmental anorthositic gabbro breccia with ~75% plagioclase; 3) fragmental gabbroic breccia with approximately equal proportions of plagioclase, pyroxene and olivine; 4) shock melt veins and pools, some of which are vesicular. Accessory FeNi-metal, silica, ilmenite, troilite, chromite, and phosphate were observed in the fragmental breccias.

Geochemistry: (C. Agee and N. Muttik, UNM) Olivine gabbro: olivine Fa_52.9.8±7.1, Fe/Mn=100±12, n=6; clinopyroxene Fs_31.1±15.8Wo_22.1±7.6, Fe/Mn=41±10, n=7; plagioclase An_89.9±3.8Ab_8.9±3.4Or_1.1±0.8, n=3; anorthositic gabbro breccia: olivine Fa_30.6±3.0, Fe/Mn=104±7, n=21; clinopyroxene Fs_39.4±15.8Wo_21.7±10.9, Fe/Mn=66±11, n=21; plagioclase An_96.2±0.8Ab_3.5±0.8Or_0.2±0.1, n=6; gabbroic breccia: olivine Fa_40.3±2.9, Fe/Mn=98±5, n=6; clinopyroxene Fs_35.4±14.3Wo_23.3±10.0, Fe/Mn=63±10, n=9; plagioclase An_93.0±1.6Ab_6.6±1.6Or_0.4±0.1, n=4; Shock melt (10 μm defocused electron beam, proxy for bulk meteorite composition): SiO₂=45.1±2.0, TiO₂=0.54±0.38, Al₂O₃=24.3±6.2, Cr₂O₃=0.21±0.19, MgO=6.5±2.9, FeO=8.2±3.8, MnO=0.11±0.05, CaO=14.9±1.9, NiO=0.03±0.07, Na₂O=0.49±0.13, K₂O=0.10±0.03 (all wt%), n=40.

Classification: Lunar (polymict breccia)

Specimens: 24 g including a probe mount on deposit at UNM; Aziz Habibi holds the main mass.