(L7 in MetBull 102 [submitted as Achondrite-ung])
no coordinates recorded
A stone weighing 134 g was found in the Sahara and sold to Chladni's Heirs. A sample was submitted for analysis and classification to the University of Washington in Seattle (A. Irving), and NWA 6348 was determined to be a metachondrite (Irving et al., 2005) with affinities to the L chondrite group. The meteorite has a shock stage of S3 and a weathering grade of W2.
Northwest Africa 6348 is a texturally evolved meteorite with grains of variable sizes, but which do not appear to constitute separate clasts. Although no chondrules were identified, some fine-grained areas might represent relict chondrules. Mineral constituents include olivine, orthopyroxene, clinopyroxene, sodic plagioclase, and opaque phases.
Northwest Africa 6348 has been classified by A. Irving as the first metachondrite from the L chondrite parent body. The term metachondrite was proposed to describe those achondrites which are texturally evolved chondrites with completely recrystallized textures resulting from high degrees of metamorphism or partial melting. They lack chondrules and have elemental abundance ratios and O-isotopic compositions that show affinities to existing chondrite groups. Meteorites described as metachondrites have been found representing the CV, CR, E, H, L, and LL groups, while unique metachondrite NWA 2788 is considered by Bunch et al. (2006) to be associated with an unknown carbonaceous chondrite parent body; if a chondrule-bearing representative of this parent body is found and identified in the future, it was suggested that it be termed a 'CT chondrite' (see NWA 2788 photos and abstract #P51E-1246). In addition, some groups of achondrites having chondrule-bearing members might also be more appropriately described as metachondrites, including the acapulcoites and winonaites as demonstrated by Monument Draw and NWA 725, respectively. These chondrule-bearing members have been referred to as 'AC chondrites' or 'W chondrites' for those associated with acapulcoites and winonaites, respectively. It should be noted that further studies of NWA 725 have determined that it may have originated on a distinct body from the IABMG irons and winonaites. The photo shown above is a 2.9 g specimen of NWA 6348.