Northwest Africa 10659 (NWA 10659)

Morocco

Purchased: 2015

Classification: Martian meteorite (Nakhlite)

History: Found near the Algeria-Mauritania border in Morocco, and sold by a Moroccan nomad/dealer. 7.2 g from a larger mass, of unknown quantity, was purchased by Jaouad Chaoui in Laayoune, Morocco.

Physical characteristics: Five individual stones of granular, friable material. One of the stones (3.870 g) still retained ~17.5 mm² of fusion crust on its surface. The interior grains are dark green, dark grey, light beige, with red-brown components.

Petrography: (J.C. Bridges and L.J. Hicks, UoL) Cumulate texture. Consists of compositionally zoned tabular pyroxenes (~65%), up to 1.5 mm in length, and larger grains of fayalite olivine (~5%). There is an interstitial mesostasis of albite and orthoclase feldspar (~30%), with exsolved Ti-rich magnetite and phosphate grains. Both olivine and mesostasis contain a secondary phase iron-silicate alteration material, compositionally resembling the ferric saponite and serpentine found in other nakhlites (Hicks et al, 2014).

Geochemistry: Olivine (cores Fa_63.3-77.6, N = 12); pyroxene (cores Fs_20.2-39.0Wo_39.2-42.3, N = 16; rims Fs_25.1-45.7Wo_37.4-42.4, N = 8); plagioclase (An_13.8-28.3Or_3.7-6.8, N = 22); alteration phase in olivine fractures (average of 72 analyses in wt.%, normalized to 100% anhydrous): SiO₂ 56.9, Al₂O₃ 0.3, FeO[Total] 37.0, MgO 3.0, CaO 1.6, Na₂O 0.2, K₂O 0.3, SO3 0.8); alteration phase in mesostasis fractures (average of 66 analyses in wt.%, normalized to 100% anhydrous): SiO₂ 57.1, Al₂O₃ 4.3, FeO[Total] 31.0, MgO 2.8, CaO 2.6, Na₂O 0.3, K₂O 1.0, P₂O₅ 0.3, SO3 0.6); Oxygen isotopes with acid wash, average of 2 powder analyses (2 mg each) on same sample (100 mg powder): δ¹⁷O: 2.990; δ¹⁸O: 5.139; Δ¹⁷O: 0.317 (R.C. Greenwood, I.A. Franchi, OU)

Classification: Martian meteorite, nakhlite. Possibly paired with NWA 10153.

Specimens: 5.6 g in 3 pieces, plus three polished sections at ULei. The remaining material is held by G. Ensor.