Sample No.: ALHA78109

Location: Allan Hills

Field No.: 248

Weight (gms): 233.2

Meteorite Type: LL5 Chondrite

Physical Description:

Dull black fusion crust covers approximately 75% of this approximately 7.0 x 5.5 x 3.5 cm sample. The portions of the specimen devoid of fusion crust are light gray in color with abundant dark gray chondrules that are as great as 2 cm. in maximum diameter. These chondrules are easily removed from the exterior of the sample, and many fall out on handling. Several larger gray clasts and what appears to be troilite nodules, ranging from ~3 mm. to 10 mm. are also present. Where the sample was cleaved to divide with Japan, a light gray interior that is essentially free of iron oxidation was exposed. However, some material that appears to be troilitic in the interior of the specimen is oxidized and friable.

Petrographic Description: Brian Mason

Chondrules are prominent and well-defined, 0.6-2.4 mm in diameter; some are broken or deformed. A variety of types is present, the commonest being granular olivine, barred olivine, and fine-grained pyroxene. The matrix is dominantly olivine with lesser amounts of pyroxene, and a little nickel-iron and troilite; plagioclase is present as very small grains difficult to recognize. The section shows a little limonitic staining around some metal grains. Microprobe analyses gave the following compositions: olivine, Fa28; orthopyroxene, Fs23; plagioclase, An11. The meteorite is classified as an LL5 chondrite.