CK3 - Anomalous
NWA 1665
Carbonaceous chondrite
Northwest Africa
A single meteorite of 1,185 g covered by 94% fusion crust was found in 2002 by an anonymous finder in the Occidental Saharan desert. Classification and mineralogy (A. Greshake and M. Kurz): it is a type 3 carbonaceous chondrite with chondrules, irregular shaped olivine-rich objects, and mineral fragments set into a fine-grained matrix of Fe-rich olivine, Ca-pyroxene, troilite, and FeNi-metal; chondrules have a mean diameter of 130 µm in size and porphyritic olivine and pyroxene chondrules clearly dominate over radiating or cryptocrystalline types: olivine which makes 50% of the matrix has Fa25.7 (range Fa0.7-37.6); pyroxene, Fs12 (range Fs2.5-48.3);
Oxygen isotopic compositions (R. Clayton and
T. Mayeda, UChi): δ18O = -1.03‰, δ17O = -4.95‰ and (I. Franchi and R. C.
Greenwood, OU): δ18O = -1.88‰, δ17O = -5.43‰,
Δ17O = -4.45‰ are clear of the CO3 chondrite field and possibly located on an
extension of the CK3 range;
Shock stage, S1; weathering grade, W2. Specimens: Main mass with anonymous finder; type specimen 22 g plus one polished thin section MNB.
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