Northwest Africa 10810 (NWA 10810)

Mauritania

Purchased: 2016

Classification: Lunar meteorite

History: Two stones weighing 126.2 and 276.2 g were found in Mauritania and subsequently purchased in Rissani in 2015. J. Donald Cline and John Sinclair acquired the samples from a meteorite prospector at the Tucson Gem and Mineral Show in February 2016.

Physical characteristics: Sample has an irregular-ovoid shape and lacks fusion crust. The exterior surface is weathered and light orangish-gray in color. One half of the stone shows an obvious brecciated texture composed of dominant light-colored clasts in a dark matrix. The other half appears to have been buried and contains an orangish layer of caliche. One edge has a window cut into the stone showing a mixture of rounded dark and light-colored lithic and mineral clasts in a dark brown matrix. One slice contains an FeNi grain.

Petrography: Description and classification (A. Love, App): Sample is a polymict breccia composed of 5 mm sub-rounded to angular lithic clasts and mineral clasts set within a micro-vesicular black glassy matrix. Up to 5 mm subrounded to subangular clasts of olivine gabbro with exsolved pyroxenes, troctolite, subophitic olivine basalt and exsolved pyroxenes, granulitic anorthosite and poikolitic crystalline impact melt breccia are the dominant lithic fragments represented in the sample. Additionally, the sample contains mineral grains, and symplectites composed of fayalite, Si-rich grains and Ca-pyroxene in addition to glassy spherules and flow-banded agglutinates. Accessory minerals ilmenite, ferroan chromite, fayalite and a silica polymorph.

Geochemistry: (A. Love, App): Olivine (Fa_23.1-45.3; FeO/MnO=95.8-114.7, N=20), pigeonite (Fs_25.8-30.1Wo_16.3-7.3 N=14; Fs_46.4-57.2Wo_20.0-7.8; FeO/MnO=54.4-73.5, N=4); augite (Fs_16.5-21.5Wo_23.8-38.5; FeO/MnO=47.2-52.0, N=9); fayalite (Fa_90.7-97.6; FeO/MnO=93.3-96.8, N=6); plagioclase An_95.0±2.7Or_0.2±0.2, N=13). Bulk Composition: (R. Korotev, WUSL): INAA of 100 mg gave (in wt%) Na₂O 0.4, FeO 10.9; (in ppm) Sc 19.7, Cr 17.8, Co 42.1, Ni 220, La 7.3, Sm 3.3, Eu 0.91, Yb 2.3, Lu 0.3, Hf 2.5, Th 1.1.

Classification: Lunar (mingled regolith breccia)

Specimens: PARI holds the main masses (276.2 and 89.07 g). A slice and an end cut weighing 20.82 g and one polished thin section are on deposit at App.