Northwest Africa 14346 (NWA 14346)

(Northwest Africa)

Purchased: 2021

Classification: Carbonaceous chondrite (CVox3)

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 ~2 mm. CAIs with sizes up to 1.2 mm are observed. Type II chondrules are rare. Opaque minerals are sulfides with varying Ni contents, traces of Ni-rich metal, and some magnetite. Most metal is oxidized by terrestrial weathering.

Geochemistry: Mineral compositions and geochemistry: The mean composition of olivine in chondrules and chondrule fragments is Fa_8.4±6.4 (Fa_1.4-27.9); n=18. The mean composition of low-Ca pyroxene in chondrules and chondrule fragments is Fs_1.9±1.3 Wo_1.2±0.3 (Fs_0.7-4.6 Wo_0.9-1.7); n=15. Mean Ni concentration in sulfides (wt%): 10.8±11.6 (0.0-26.7); n=8. Ni concentration in metal (wt%): 66.0; n=1.

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. Mean Ni concentrations in metal and sulfide are in the range of the oxidized subgroup Gattacceca et al., 2020.