Northwest Africa 11406 (NWA 11406)

Algeria

Purchased: 2016

Classification: Carbonaceous chondrite (CO3)

History: The meteorite was found in Algeria in 2014 by nomads. Zs. Kereszty purchased it in the Munich Show 2016 from Adam Aithiba (Moroccoan meteorite seller) and made 3 thin sections.

Physical characteristics: The meteorite contains up to 500 μm sized chondrules, CAI and AOA grains embedded in dark, poorly transparent matrix that makes up around half of the meteorite. Some chondrules are fragmented. The whole meteorite is substantially weathered.

Petrography: Minerals: 80% olivine(above 60 μm Fe-rich olivine, and olivine with Fe-rich rim and Mg rich core are also present), 10% px (10-20 μm-sized, at the rim of chondrules and AOAs), opaque mineral 4%: goethite, pentlandite, pyrite, chromite, troilite, kamacite, taenite, other accessories: 6% (wollastonite, jadeite, feldspar). CAI-AOA: 12% (up to 300 μm-sized, coarse-grained, with sinusoidal, multi-cored with fine-grained rims), matrix: 38% (including 10-20 µm olivine crystals, submicroscopic px, opaque minerals, chondrules: 49% (size: up to 400 μm, average: 200 μm). Weathering: clay around chondrules and between larger olivine grains, and iron-oxide veins. Shock effects: intergranular fractures and brecciation.

Geochemistry: olivine:: Fa_36.7±18 (Fa_0-72.7, N=93); cpx: Fs_15.5±15.7Wo_38.0±10.6 (Fs_0.0-54.8Wo_8.5-48.3 N=20); and opx: Fs_2.3±1.3Wo_1.8±1.7, (Fs_0.0-5.3Wo_0.0-4.8, N=13

Classification: CO3

Specimens: 3 slices of 23 g at CSFK