Northwest Africa 10985 (NWA 10985)

(Northwest Africa)

Purchased: 2015

Classification: Lunar meteorite (gabbro)

History: Purchased by Jay Piatek in Morocco, 2015.

Physical characteristics: Single stone, weathered exterior without fusion crust. A polished saw cut surface reveals two distinct lithologies separated by a sharp boundary offset, with numerous truncated grains. One lithology is a light colored, medium-grained gabbro with elongate subhedral prismatic yellow-green pyroxenes and white subhedral plagioclase laths. The second lithology is a dark colored, fine-grained breccia with yellow-green pyroxene fragments scattered throughout. Fine shock melt veins visible.

Petrography: (C. Agee, UNM) Microprobe examination of a polished mount shows igneous-zoned pigeonite and augite, plagioclase, olivine, fayalite, hedenbergite, pyroxferroite, Fe-sulfide, ilmenite, chromite, Ti-magnetite, apatite, silica, and symplectites.

Geochemistry: (C. Agee and S. Spilde, UNM) Olivine Fa_38.1±21.2, Fe/Mn=95±8, n=31; pigeonite Fs_45.9±12.2Wo_17.8±5.5, Fe/Mn=63±10, n=29; augite Fs_41.2±16.9Wo_30.8±3.9, Fe/Mn=63±11, n=18; pyroxferroite Fs_84.2±1.4Wo_14.8±1.4, Fe/Mn=63±2, n=3; plagioclase An_89.5±3.4Ab_9.8±3.1Or_0.7±0.6, n=27; shock melt (proxy for bulk composition) SiO₂=48.0±2.6, TiO₂=1.2±0.7, Al₂O₃=11.3±6.0, Cr₂O₃=0.4±0.2, MgO=11.6±4.3, FeO=16.5±2.7, MnO=0.24±0.05, CaO=10.9±3.0, Na₂O=0.28±0.17, K₂O=0.17±0.11 (all wt%), n=10.

Classification: Lunar gabbro

Specimens: 20.2 g including a probe mount on deposit at UNM, Jay Piatek holds the main mass.