Sample No.: WIS91614

Location: Wisconsin Range

Dimensions (cm): 6.0 x 5.0 x 3.0

Weight (g): 299.7

Meteorite Type: Medium octahedrite, IIIAB?

Macroscopic Description: Roy S. Clarke. Jr,

This is a generally blocky shaped specimen with rounded edges due to ablation working. It has a roughly convex surface that appears to have been the anterior surface during flight and a concave posterior surface. The specimen is covered with a thin secondary oxide coating, with possibly a few small patches of fusion crust remaining in deeper surface depressions. A 19 g slice was removed perpendicular to the anterior and posterior surfaces, resulting in butts of 90 g and 165 g. Approximately hag of the slice (4 cm2) was metallographically polished and etched.

Polished Section Description: Roy S. Clarke. Jr, The exterior edge of the section has a 1.5 mm heat altered zone, and a patch of layered melt crust 70 µm thick is present. The kamacite band width is ~1.0 mm. Kamacite/kamacite grain boundaries have been penetrated by terrestrial weathering into the interior of the specimen, and some have been widened in the process and filled with oxides. Subgrain boundaries are present in the less shocked kamacites, as are submicron inclusions, probably rhabdites. A number of the kamacites have a well developed ε structure resulting from shock. Taenite lamellae are present, frequently enclosing plessite areas. Many plessite areas have martensitic centers. Troilite is abundant, with one inclusion of 0.5 cm diameter. It is cracked into small domains that are essentially untwinned, and perhaps 10% of this inclusion is daubreelite. Smaller trollite globules are present close to this large inclusion. A separate troilite is 5 mm long and 0.5 mm wide. This troilite is twinned on a very fine scale and has a central spine of daubreelite. A few small troilite-daubreelite inclusions are distributed throughout. Occasional small schreibersites or schreibersite/daubreelite inclusions are present. This is a medium odahedrite, probably a IIIAB.