Northwest Africa 10463 (NWA 10463)

(Northwest Africa)

Purchased: 2015 Aug 4

Classification: Angrite

History: Purchased on August 4, 2015, from Aziz Habibi in Erfoud, Morocco.

Physical characteristics: Single mass, coated in desert soil, no fusion crust. Broken surfaces show a fresh polycrystalline aggregate of mm-size green, yellow, and black minerals. Friable.

Petrography: (C. Agee, UNM) This meteorite has a granular texture of fassaite (~50%) and olivine (~30%) up to ~1 mm in diameter, with stubby plagioclase laths (~15%) up to 300 μm in length. Some olivines have exsolved kirschsteinite. Accessory titanium-iron oxides and troilite were observed.

Geochemistry: (C. Agee, N. Muttik, A. Santos, UNM) Fassaite Fs_21.6±7.9Wo_53.5±1.2, range: Fs_16.2-32.7, Fe/Mn=104±17, Al₂O₃ (wt%)=8.1±1.6, n=12; olivine Fa_59.7±14.8Lrn_3.9±2.1, range Fa_32.6-79.6, Fe/Mn=88±9, n=16; kirschsteinite Fa_47.7±1.7Lrn_43.5±1.2, Fe/Mn=69±2, n=4; plagioclase An_99.4±0.1, n=3.

Classification: Based on the strong igneous zoning of olivine and fassaite this is likely an angrite. It lacks a fine-grained groundmass found in more quickly cooled angrites, and shows kirschsteinite exsolution in olivine. Although there are some textural similarities with NWA 4590, and broadly similar fassaite compositions to LEW 87051, this meteorite is likely unpaired, thus representing a new angrite type.

Specimens: 20.6 g including a probe mount on deposit at UNM, DPitt holds the main mass.