Northwest Africa 4466

Northwest Africa

Find: 2006

Carbonaceous chondrite (CV3)

History: Devin Schrader purchased the sample at the Tucson Gem and Mineral Show on 29 January 2006 from a Moroccan meteorite dealer.

Physical characteristics: The total mass of the meteorite before cutting was 71.25 g. It is composed of three pieces: one large piece with two small fragments (1.105 and 2.886 g) that fit back onto the main piece. The meteorite has weathered fusion crust on about 10% of its surface. The color of the meteorite is gray, with visible chondrules and a CAI on the surface.

Petrography: (D. Schrader, UAz; H. Connolly, KCCU) The meteorite contains olivine, pyroxene, plagioclase, Fe,Ni metal, chondrules, and CAIs. The meteorite is dominated by large chondrules (~1 mm) and fine-grained matrix. Some veins of apparent alteration material cross-cut the rock. The rock contains two lithologies. 1) The host lithology contains abundant, well-defined chondrules and some chondrule fragments. The textural types of chondrules observed are BO, PP, PO, and GO with an overall size range for the chondrules of 0.29–2.05 mm. The section contains one highly altered type A CAI. 2) A small clast lithology (~0.4 × 0.7 cm) that contains smaller, closely packed chondrules in contact with a large type B CAI (~0.4 × 0.8 cm). The textural types of chondrules are BO, C, PO, and a Ca-Al-rich chondrule with an overall size range for the chondrules of 0.25–0.63 mm.

Mineral compositions and geochemistry: (D. Schrader, K. Domanik, and D. Hill, UAz) Lithologies: 1) chondrules contain Fa_0.39–9.24 (average = Fa_2.70±2.42), Fs_0.71–3.59 (average = Fs_1.83±0.97), and Wo_0.40–6.93 (average = Wo_2.29±1.87). 2) Chondrules contain Fa_{16.26–42.01} (average = Fa_22.04±9.30), Fs_{26.60–28.58} (average = Fs_27.71±0.92), and Wo_0.20–3.23 (average = Wo_1.06±1.45).

Classification: Carbonaceous chondrite (CV3).

Type specimen: A total of 14.483 g is on deposit at KCCU. D. Schrader holds the main mass of 54.767 g in four pieces.