Northwest Africa 8632 (NWA 8632)

Morocco

Purchased: 2014 Jun

Classification: Lunar meteorite (basalt)

History: Purportedly found near Chwichiya in 2013 and purchased by Luc Labenne in June 2014 from a dealer in Ouarzazate, Morocco.

Physical characteristics: A single, small, dense black stone (23.8 g) with a flat, squarish shape and no fusion crust. Magnetic susceptibility log χ = 3.08 (X in nm3/kg) (J. Gattacceca, CEREGE).

Petrography: (A. Irving and S. Kuehner, UWS) Porphyritic texture. Subhedral zoned olivine phenocrysts (up to 2.3 mm long, yellowish in thin section) are set in a groundmass composed mainly of elongate, zoned clinopyroxene grains (clear with pink rims), smaller olivine grains and interstitial regions (opaque in thin section) consisting of ilmenite needles, Ti-chromite, fine clinopyroxene, fayalite and glass. No plagioclase was found. Small patches and veinlets of pale yellow devitrified glass are present.

Geochemistry: Olivine phenocrysts (cores Fa_32.5-32.8, FeO/MnO = 90-100, N = 3; rim Fa_48.8, FeO/MnO = 98), groundmass olivine (Fa _72.6-74.1, FeO/MnO = 91-97, N = 3), augite (Fs_23.7-27.1Wo_40.1-40.5, FeO/MnO = 53-55, TiO₂ = 2.4-2.6 wt.%, Al₂O₃ = 5.9- 6.1 wt.%, N = 2), subcalcic augite (Fs_26.6-27.0Wo_30.8-36.1, FeO/MnO = 54-60, TiO₂ = 1.9-2.1 wt.%, Al₂O₃ = 4.7-5.6 wt.%, N = 2), ferroan subcalcic augite rim (Fs_41.9Wo_34.1, FeO/MnO = 63, TiO₂ = 3.2 wt.%, Al₂O₃ = 8.1 wt.%). Bulk composition (R. Korotev, WUSL) INAA of subsamples gave the following mean abundances (in wt.%) FeO 22.6, Na₂O 0.28; (in ppm) Sc 51.1, Ni 70, La 7.8, Sm 4.7, Eu 0.89, Yb 4.1, Lu 0.58, Hf 3.4, Th 1.25.

Classification: Lunar (mare basalt).

Specimens: 4.6 g including one polished thin section, one polished thick section and one polished mount at UWB. The main mass is held by Labenne.