|Allan Hills A78252|
|Basic information||Name: Allan Hills A78252|
This is an OFFICIAL meteorite name.
This meteorite may also be called Allan Hills 78252 (ALH 78252) in publications.
Observed fall: No
Year found: 1978
Country: Antarctica [Collected jointly by ANSMET (US) and NIPR (Japan)]
Mass: 2.79 kg
This is 1 of 72 approved meteorites (plus 1 unapproved name) classified as Iron, IVA. [show all]
Search for other: IVA irons, Metal-rich meteorites, and Iron meteorites
Writeup from AMN 3(2):
This text was reprinted from AMN 3(2) in AMN 4(1). In some cases, it may be an updated version from the original.
Sample No.: ALHA78252
Location: Allan Hills
Field No.: 242
Weight (gms): 2789.0
Meteorite Type: Iron-Group III A
The T surface of the meteorite was in contact with the ice at the time it was recovered. The surface (T) is convex and very smooth, the B surface is semi-concave. The meteorite is metallic brownish-black, with many spots of oxidation staining that are reddish-brown. In the center of the B surface is a hole ~4 cm in diameter. Striations exist on the T surface probably due to ablation during entry, the striations in the E-W direction dominate.
Tentative Classification: Roy S. Clarke, Jr.
An area of approximately 30 cm2 of macroetched surface was examined. Kamacite band widths are in the 0.5 mm range, with a length to width ratio ranging from 10 to 50. One edge of the slice has a continuous rim of α2 produced by atmospheric ablation. Neumann bands are present and the kamacite has a matte appearance. Some kamacite bands are mildly deformed. Kamacite grains are continuously bordered by taenite or taenite-plessite areas. Plessite areas cover perhaps 40% of the surface area. Several small troilites are present. External weathering is moderately severe. This specimen is a medium octahedrite (Om) of narrow band width, probably a Group III A meteorite.
[Addendum to AMN 4(1)]
This specimen is a fine octahedrite, a Group IV A meteorite (R. S. Clarke, Jr.).
|References:||Published in Antarctic Meteorite Newsletter 3(2) (1980), JSC, Houston|
Published in Meteoritical Bulletin, no. 76, Meteoritics 29, 100-143 (1994)
This is 1 of 34733 approved meteorites from Antarctica (plus 6183 unapproved names)
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