Northwest Africa 5406

Morocco

Find: July 2008

Achondrite (lunar, feldspathic breccia)

History: Purchased by Greg Hupé in July 2008 from a dealer in Ouarzazate, Morocco, who reported that these stones were found in the same area as NWA 4936 near Siksou Mountain in southern Morocco.

Physical characteristics: Six, dark gray, mostly very fine-grained stones (total weight 281 g) with hackly fracture and lacking obvious fusion crust. The interior of each stone resembles devitrified glass with dispersed small white clasts.
Petrography: (A. Irving and S. Kuehner, UWS) All specimens are composed of small mineral clasts and sparse lithic clasts in a very fine-grained matrix (which has the texture of an impact melt with heterogeneous, “swirly” glass). Mineral clasts include anorthite, olivine, pigeonite, subcalcic augite, ilmenite, troilite, and irregular-shaped grains of kamacite.

Geochemistry: Pigeonite (Fs_34.7Wo_9.8, FeO/MnO = 59.9), augite (Fs_55.8Wo_26.4, FeO/MnO = 72.6), olivine (Fa_25.7–27.0, FeO/MnO = 85.3–120), plagioclase (An_96.2–97.2Or_0.0). Bulk composition (R. Korotev, WUSL): FeO 5.8 wt%, Th 2.0 ppm, Sc 9.1 ppm, Ni 520 ppm, Sm 6.3 ppm.

Classification: Achondrite (lunar, feldspathic breccia). These stones have essentially the same distinctive textures, mineral compositions and bulk composition as NWA 4936, and are almost certainly paired with the latter stones.

Specimens: A total of 20.0 g of is on deposit at UWS. The main masses are held by Mr. G. M. Hupé.