Sample No.: ALHA80104

Location: Allan Hills

Field No.: 1011

Weight (gms): 882.0

Meteorite Type: Ataxite

Physical Description,: Roy S. Clark, Jr.

This specimen is an irregularly shaped individual, 11 cm x 7 cm x 4 cm. One prominent rounded surface appears to have been ablation-shaped, and a second fairly large and comparatively smooth surface appears to have been the under side while the specimen was exposed at the surface of the ice. The meteorite is covered with a fairly uniform dark reddish brown iron oxide, and no fusion crust seems to remain. There are several deep linear incisions into the body of the meteorite that are possibly due to either preferential ablation or weathering of schreibersite inclusions exposed at the surface.

Tentative Classification: Roy S. Clarke, Jr.

A microetched surface area of approximately 7 cm² was examined. A heat-altered zone is present over part of the external surface of the specimen. The metallographic matrix is a martensitic plessite. Kamacite spindles less than 0.1 mm wide, and generally less than ten times their width in length, are moderately uniformly distributed in a vague Widmanstätten pattern orientation. The kamacite spindles frequently enclose small schreibersites. Three large schreibersite areas enclosed in swathing kamacite as wide as 0.2 mm are present. The largest such area is 8 mm long. Weathering has penetrated 0.5 cm into the mass in one area. Chemical data and a more thorough metallographic examination will be required to classify this meteorite precisely.