Northwest Africa 10404 (NWA 10404)

(Northwest Africa)

Purchased: 2015 May

Classification: Lunar meteorite (feldspathic breccia)

History: Purchased by Darryl Pitt in May 2015 from a dealer in Ouarzazate, Morocco.

Physical characteristics: A single stone (229 g) lacking fusion crust. Interior slices exhibit angular mineral clasts plus rounded colorless, brownish and greenish glassy objects in gray, partly vesicular matrix

Petrography: (A. Irving and S. Kuehner, UWS) Vitric fragmental breccia composed of angular to rounded lithic clasts plus mineral clasts of anorthite, olivine, pigeonite, orthopyroxene, subcalcic augite, augite and rare Ti-chromite, troilite and taenite in a partly vitreous matrix. Some lithic clasts are fine grained, plagioclase-phyric crystalline lithologies, but many consist of partly-devitifried glass with bulk compositions intermediate between those of anorthite, olivine and low-Ca pyroxene. The latter consist of isotropic cores (colorless to pale brown in thin section) mantled by aggregates rich in polycrystalline, spherulitic birefringent crystallites within zones parallel to clast margins and constituting ~50% of clast volumes.

Geochemistry: Olivine (Fa_26.4; Fa_47.2, FeO/MnO = 77-84, N = 2), orthopyroxene (Fs_37.6Wo_3.2, FeO/MnO = 64), pigeonite (Fs_21.1-25.9Wo_15.5-11.3, FeO/MnO = 59-60, N = 2), subcalcic augite (Fs_21.9Wo_32.2, FeO/MnO = 51), augite (Fs_20.0Wo_37.9, FeO/MnO = 46), plagioclase (An_96.1-97.0Or_0.0, N = 3). Bulk composition (R. Korotev, WUSL) INAA of subsamples gave the following mean abundances (in wt.%) FeO 3.8, Na₂O 0.36; (in ppm) Sc 6.8, La 4.2, Sm 2.0, Eu 0.83, Yb 1.5, Lu 0.21, Th 0.74.

Classification: Lunar (feldspathic vitric regolithic breccia).

Specimens: 20.61 g including one polished thin section at UWB; main mass with DPitt.