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| Allan Hills A81059 | |||||||||||||||||||||
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| Basic information | Name: Allan Hills A81059 This is an OFFICIAL meteorite name. Abbreviation: ALHA81059 This meteorite may also be called Allan Hills 81059 (ALH 81059) in publications. Observed fall: No Year found: 1981 Country: Antarctica [Collected by US Antarctic Search for Meteorites program (ANSMET)] Mass:  540 g | ||||||||||||||||||||
| Classification history: |
This is 1 of 4 approved meteorites classified as Mesosiderite-B1. [show all] Search for other: Class B mesosiderites, Mesosiderites, and Metal-rich meteorites | ||||||||||||||||||||
| Writeup |
Writeup from AMN 6(1):
Sample No.: ALHA81059 Location: Allan Hills Field No.: 1282 Weight (gms): 539.5 Meteorite Type: Mesosiderite
Physical Description: Roberta Score The exterior of this mesosiderite has many greenish pyroxene grains, which all show cleavage faces. Several of the larger ones (up to 1.5 x 1 cm) can easily be removed. The stone appears to be fairly weathered with many fractures criss-crossing the exterior. A few small patches of fusion crust remain. Weathering of the interior is extensive. Dimensions: 9.5 x 5 x 5.5 cm.
Petrographic Description: Brian Mason The section consists largely of orthopyroxene clasts ranging up to 10 mm in maximum dimensions, together with about 30% of nickel-iron in grains up to 0.6 mm; a little troilite is present. The meteorite is extremely weathered and seamed with brown limonite. Microprobe analyses shows that the orthopyroxene is somewhat variable in composition, ranging from Fs25 to Fs32, with a mean of Fs28; mean weight per cent CaO is 1.2, MnO 0.7, A12O3 0.6, TiO2 0.2. Small amounts of olivine (Fa28), plagioclase (An93), merrillite, and an SiO2 phase (probably tridymite) were detected with the microprobe. The meteorite is a mesosiderite, the second from the Allan Hills. It appears to be different from the previous one, ALHA77219. | ||||||||||||||||||||
| Data from: MB76 Table 2 Line 582: |
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| References: | Published in Antarctic Meteorite Newsletter 6(1) (1983), JSC, Houston Published in Meteoritical Bulletin, no. 76, Meteoritics 29, 100-143 (1994)
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Geography:
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Statistics: This is 1 of 43856 approved meteorites from Antarctica (plus 3802 unapproved names) | ||||||||||||||||||||
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