Northwest Africa 14420 (NWA 14420)

(Northwest Africa)

Purchased: 2021

Classification: Carbonaceous chondrite (CV3)

History: Colvin purchased from a dealer in Mauritania via the internet.

Petrography: (M. Hutson, D. Sheikh, A. Ruzicka, Cascadia): In thin section, the sample contains chondrules and refractory inclusions including CAIs and AOAs (up to 4 mm across, with an average size of ~1 mm) set in a fine-grained dark matrix containing accessory magnetite grains. No metal was observed. The matrix comprises about 55% of the thin section area.

Geochemistry: Olivine Fa_6.8±7.3, N=75; Low-Ca pyroxene Fs_1.1±0.4Wo _1.4±1.1, N=12; Pigeonite Fs_5.1±0.2Wo_5.5±1.0, N=4; Augite Fs_1.6±1.1Wo_39.9±4.2, N=22. Pyroxenes contain aluminum and titanium; Al₂O₃ ranges (all wt% values) are 0.5-1.3 in low-Ca pyroxene, 2.5-4.0 in pigeonite, and 2.2-11.2 in augite; TiO₂ ranges are 0.1-0.3 in low-Ca pyroxene and pigeonite, and 0.3-1.2 in augite.

Classification: Texture and chemistry, including abundant refractory inclusions indicates a CV3 chondrite. Lack of metal and presence of magnetite suggests an oxidized CV3; low magnetic susceptibility favors CVoxA3 from Gattacceca et al., 2020.

Specimens: Cascadia holds 35.6 g in three pieces, as well as a polished thin section; Colvin holds the main mass.