Northwest Africa 8333 (NWA 8333)

(Northwest Africa)

Purchased: 2014 Jan

Classification: Carbonaceous chondrite (CV3)

History: Purchased from a mineral dealer in Berlin, Germany, who bought the sample in Morocco.

Petrography: (K. Metzler, IfP) Chondrules, CAIs and AOAs are embedded in a fine-grained dark matrix (about 30 vol% matrix). The matrix is Allende-like, mainly consisting of tiny (<5-20 µm) elongated olivine grains. Most chondrules have apparent diameters between 0.5 and 2 mm, the largest up to 4 mm. CAIs with sizes up to 1.2 cm and dark inclusions up to 1.5 cm in size are observed. A directional fabric is visible due to the parallel orientation of elongated CAIs and AOAs.

Geochemistry: Composition of small olivine grains in matrix is Fa_40.5±1.5 (Fa_37-41); n=10. Random measurements of olivine grains revealed Fa_17.8±12.0 (Fa_1-46); n=23. Random measurements of low-Ca pyroxene grains revealed Fs_2.0±1.3Wo_2.2±1.8 (Fs_1-4Wo_1-5, n=13).

Classification: CV chondrite based on CAI and AOA occurrence, size of chondrules and CAIs, chondrule-matrix ratio, and mineral chemistry. Petrologic type 3 based on the chemical variability of olivine and pyroxene.