Sahara 00177

Found 2000

Carbonaceous chondrite (C3/4, CV-like)

A 12 g stone was found by Labenne. Mineralogy and classification (M. Bourot-Denise, MNHNP): related to reduced CVs, similar to Coolidge and Loongana 001. Chondrules, chondrule fragments and CAIs make up ~75 vol% of the meteorite. Overall, chondrules are smaller than in Allende, with a mean size ~500 µm. CAIs (~10 vol%) are large, up to 1 mm in size. The largest and most abundant chondrules are type-I, porphyrytic olivine-pyroxene chondrules, often of irregular shape, with olivine crystals in the 10–40 µm size range, and abundant opaque beads. Less abundant metal-poor barred olivine, radial pyroxene and other chondrules are generally smaller (100–300 µm) and more rounded. Olivine, Fa8.0 ± 1.0 (range: 5.0–9.6); low-Ca pyroxene Fs7.6 ± 2.4 (range: 3.4–10.5). Chondrule mesostasis is completely devitrified. A few chondrules are partially rimmed with silica (as is the case in Coolidge). Fe-Ni metal is kamacite, with minor taenite. Weakly shocked, metal is not warped, troilite is monocrystalline. Moderately weathered; metal grains, especially those in the matrix or on chondrules edges, have a 2–5 µm-wide limonite rims; veins in chondrules silicates are also filled with limonite; troilite is unaltered. Type specimen, 4 g, MNHNP, main mass with Labenne.