Sample No.: ALHA81011

Location: Allan Hills

Field No.: 1435

Weight (gms): 405.7

Meteorite Type: Eucritic Breccia (possibly a genomict breccia)

Physical Description: Roberta Score

Rounded with scattered patches of black fusion crust, this breccia is clast; rich. Several types of clasts are present-typical eucritic clasts, pinkish-white clasts and massive gray clasts. These clasts range in shape from rounded, to lens-shaped, to rectangular, and many are larger than 1.5 cm long. The exterior matrix has a light gray color while the fresh interior matrix is very fine-grained and black. Several areas of oxidation are visible. Dimensions: 8 x 6 x 5 cm.

Petrographic Description: Brian Mason

The meteorite is a breccia of eucritic clasts up to 10 mm in maximum dimension, the clasts sitting in a minor amount of dark glass filled with comminuted grains of pyroxene and plagioclase. The clasts consist of pyroxene and plagioclase and show a variety of textures--finely granular, subophitic, and gabbroic. Microprobe analyses show pyroxene compositions corresponding to pigeonite and augite and clustering around two mean compositions, WoEn36Fs60 and Wo35En32Fs33, with a few intermediate values. Plagioclase has fairly uniform composition, An87-91, mean An88. The meteorite is a eucritic breccia; although it appears to be polymict, the uniformity of mineral compositions suggest a considerable degree of equilibration, and it may be a genomict breccia.