Northwest Africa 14345 (NWA 14345)

(Northwest Africa)

Purchased: 2021

Classification: Carbonaceous chondrite (CVred3)

Petrography: (K. Metzler, IfP) Chondrules, CAIs, and AOAs are embedded in a dark fine-grained matrix, (~30-40 vol% matrix). Most chondrules have apparent diameters between 0.2 and 1 mm, some up to 4 mm. CAIs with apparent sizes up to 9 mm are observed. Type II chondrules are rare. Opaque minerals are dominated by Ni-free sulfides and metallic iron with varying Ni concentration. Most metal is oxidized by terrestrial weathering.

Geochemistry: Mineral compositions and geochemistry: The mean composition of olivine grains in chondrules and chondrule fragments is Fa_8.6±10.2 (Fa_0.4-39.7); n=17. The mean composition of low-Ca pyroxene in chondrules and chondrule fragments is Fs_1.2±0.3 Wo_1.0±0.2 (Fs_0.7-1.5 Wo_0.7-1.4); n=13. Ni concentration in sulfides (wt%): 0.1±0.1 (0.0-0.3); n=15. Ni concentration in metal (wt%): 30.3±21.4 (5.4-54.9); n=10.

Classification: CV chondrite based on CAI and AOA occurrence, apparent sizes of chondrules and CAIs, chondrule-matrix ratio, and mineral chemistry. Petrologic type 3 based on the chemical variation of olivine and pyroxene. The very low Ni content of sulfides is typical of the reduced subgroup Gattacceca et al., 2020.