Northwest Africa 10038 (NWA 10038)

Morocco

Purchased: 2014

Classification: Ordinary chondrite (L5)

History: Purchased by Nicola Castellano at the Genova Mineral Fair in May 2014 from a Moroccan dealer.

Physical characteristics: Single stone, dark brown crust. The sawn surface shows dark-gray, very fine-grained, shock-melted veins up to 2 mm wide intersecting the coarse grained, light gray chondritic matrix.

Petrography: (V. Moggi Cecchi, G. Pratesi, S. Caporali, UniFi) Two distinct domains have been observed on a thin polished section by means of microprobe examination: the chondritic host shows an equilibrated chondritic texture, with a crystalline matrix surrounding few clearly detectable chondrules (mainly BO, POP and PP types). Main matrix phases are olivine, orthopyroxene, minor plagioclase and diopside, Fe-Ni metal and troilite; the shock-melted domain displays olivine grains set in a microcrystalline to glassy portion, green in plane polars, made of quenched silicates (mainly pigeonite) with scattered rounded metal and troilite blebs, up to 20 μm wide.

Geochemistry: (V. Moggi Cecchi, G. Pratesi, S. Caporali, M.Zoppi, UniFi) Chondritic domain: olivine (Fa_25.0±0.2, Fe/Mn=50±2, n=7); low-Ca pyroxene (Fs_21.0±0.1En_77.7±0.3Wo_1.3±0.0, 0.49 TiO₂, 0.42 Al₂O₃, 0.68 Cr₂O₃, all wt. %; Fe/Mn=30±2, n=7); diopside (Fs_7.4En_{47.7±0.3±0.1}Wo_44.9±0.3; 0.49 TiO₂, 0.42 Al₂O₃, 0.68 Cr₂O₃, 0.16 MnO, 0.46 Na₂O, all wt. %); shock melted domain: olivine grains (Fa_22.9±0.6, Fe/Mn=53±2, n=10); microcrystalline portion (Fs_21.8±0.3En_73.7±0.4Wo_4.5±0.1, 3.33 Al₂O₃, 0.43 MnO, 0.08 TiO₂, 0.45 Cr₂O₃, 0.45 Na₂O, 0.23 K₂O, all wt. %, n=7).

Classification: Ordinary Chondrite (L5)

Specimens: A total of 22.5 g specimen and one thin section is on deposit at MSN-FI. Castellano holds the main mass.