Sample No.: ALHA77270

Location: Allan Hills

Field No.: Y78010502

Weight (gms): 588.9

Meteorite Type: L6 Chondrite

Physical Description:

The sample is pyramidal, with the B surface flat, approximately 90% of the specimen is covered with a dull, brownish-black fusion crust, approximately 0.5 mm thick. The surfaces not covered with fusion crust have a weathering rind. The sample has a few fractures. The specimen measures 11.0x7.0x6.0 cm. When obtaining a suitable sample for thin section preparation, whitish-gray matrix material with small metallic flakes was exposed. After the sample was cleaved into halves, it became obvious that weathering along the fractures is severe. In non-fractured areas, the weathering rind penetrates 1 to 3 mm below the fusion crust.

Petrographic Description: Brian Mason

The section shows sparse and poorly-defined chondrules, merging with the granular groundmass, which consists of olivine and pyroxene, with minor sub-equal amounts of nickel-iron and troilite; occasional small grains of plagioclase were noted. Fusion crust, up to 0.9 thick, rims part of the section. Limonitic straining and occasional grains of limonite occur in association with nickel-iron grains. Microprobe analyses show olivine (Fa24), orthopyroxene (Fs21), and plagioclase (An11) of uniform composition; a little diopside (Wo46En45Fs9) was noted in association with orthopyroxene. The meteorite is classified as an L6 chondrite.