Northwest Africa 11962 (NWA 11962)

(Northwest Africa)

Purchased: 2013

Classification: Lunar meteorite

History: In 2013, the NHMV acquired a single stone weighing 85.8 g from a Moroccan dealer.

Physical characteristics: The specimen is a flat and rounded individual with regmaglypts exhibiting a black shiny surface with in places dull brownish areas. A cut and polished face (3 cm2) reveals two different lithologies comprising a fine-grained, dark-gray matrix with mainly submillimeter-sized light clasts and a black compact area (1 × 0.5 cm) of impact melt.

Petrography: Clast-rich breccia containing fine-grained lithic and mineral clasts, brownish vesicular glass, and brownish to orange glass spherules. In places, the glass exhibits a flow-banded texture with dark-grey to black schlieren. Lithic clasts include basalts, gabbroic lithologies, breccia-within-breccia clasts and granophyric intergrowths of K-feldspar and silica. Mineral clasts include ortho- and clinopyroxenes (some showing exsolution lamellae), olivine, plagioclase (mostly anorthitic), silica, spinel (chromite, ulvöspinel), ilmenite, zircon, troilite and Fe,Ni metal.

Geochemistry: Olivine Fa_38.0±13.5 (N = 40), plagioclase An_88.2±11.2Or_0.6±0.5 (N = 37), orthopyroxene Fs_14.3±0.4Wo_1.3±1.3 (N = 63), clinopyroxene Fs_30.8±9.1Wo_23.4±13.5 (N = 43), K-feldspar (An_4.5±1.0Or_73.9±6.4, (N = 11) BaO = 1.4-3.4 wt%), exsolved pyroxene: orthopyroxene host Fs_65.5±4.8Wo_4.0±1.3 (N = 19) with augite exsolution lamellae Fs_33.0±2.3Wo_41.6±2.3 (N = 20). The oxygen isotope composition (R. Greenwood, OU) is consistent with a lunar origin (δ¹⁷O = 3.14 per mil, δ¹⁸O = 6.03 per mil, Δ¹⁷O = 0.01 per mil).

Classification: Lunar, regolith breccia. Moderate weathering.

Specimens: A mass of 80.8 g and two thin sections are on deposit at NHMV.