Sample No.: ALH83007

Location: Allan Hills

Weight (g): 285.0

Field No.: 2530

Dimensions (cm): 9.5 x 5.5 x 4

Meteorite Type: L3 Chondrite

Macroscopic Description: Carol Schwarz

Black to slightly brownish fusion crust covers this specimen. One to five sq. mm areas of fusion crust have spalled off revealing several white clasts. The interior has a dark matrix with 1-5 mm sized clasts/chondrules that are gray to yellowish in color and somewhat weathered. One large area (8 x 4 mm) is medium gray and fine grained. This specimen is very coherent.

Thin Section (,4) Description: Brian Mason

The thin section shows a close-packed aggregate of chondrules, chondrule fragments, and irregular inclusions up to 2.5 mm across in a small amount of black matrix. The matrix includes minor subequal amounts of nickel-iron and troilite. A considerable variety of chondrules is present, the most common being granular olivine with or without polysynthetically twinned clinopyroxene, porphyritic olivine, and fine-grained pyroxene. Some chondrules have intergranular, transparent, pale brown glass; in others the glass is turbid and partly devitrified. Microprobe analyses show a wide range in the composition of olivine (Fa0.5-43) and pyroxene (Fs3-37). This range of composition, together with the presence of glass and twinned clinopyroxene, indicates type 3, and the small amount of nickel-iron suggests L group; the meteorite is therefore tentatively classified as an L3 chondrite. It resembles closely ALHA79003. (Editor's note: ALHA79003 is presently classified as LL3.)