Northwest Africa 4477

Northwest Africa

Find: 2 February 2006

Ordinary chondrite (L3-7; genomict breccia)

History: Devin Schrader purchased the sample at the Tucson Gem and Mineral Show on 2 February 2006 from a Moroccan dealer.

Physical characteristics: The total mass of the meteorite before cutting was 122.25 g (two pieces, 32.50 g and 89.75 g). The color was reddish black containing lighter tan clasts.

Petrography: (D. Schrader, D. Lauretta, M. Kilgore, UAz; H. Connolly, KCCU). The meteorite contains olivine, pyroxene, plagioclase, kamacite, taenite, troilite, and Ca phosphate. In thin section there are at least four different chondritic components, including several types of clasts showing a range of grain sizes and without chondrules (~30 vol%). The main chondritic component displays brecciation representing four metamorphic grades.

Mineral compositions and geochemistry: (D. Schrader, D. Lauretta, M. Killgore, K. Domanik, and D. Hill, UAz) (EMP at UAz) The main chondritic component has olivine (Fa_1.0–25.6, average = Fa_20.2±7.1), pyroxene (Fs_2.1–27.0, average = Fs_17.5±5.7; Wo_0.01–0.42, average = Wo_0.04±0.09), and kamacite (average Ni = 5.4 ± 2.01, range 2.26–9.33; average Co = 0.72 ± 0. 10, range 0.39–0.89, all wt%).

Classification: Ordinary chondrite (L3-7; genomict breccia); S3, W1.

Type specimen: A total of 21.33 g (in three pieces and two thin sections) is on deposit at UAz (UA2031). D. Schrader holds the main mass of 100.92 g in five pieces.