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Allan Hills A81011 | |||||||||||||||||||||||||
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Basic information | Name: Allan Hills A81011 This is an OFFICIAL meteorite name. Abbreviation: ALHA81011 This meteorite may also be called Allan Hills 81011 (ALH 81011) in publications. Observed fall: No Year found: 1981 Country: Antarctica [Collected by US Antarctic Search for Meteorites program (ANSMET)] Mass: ![]() | ||||||||||||||||||||||||
Classification history: |
This is 1 of 391 approved meteorites classified as Eucrite-pmict. [show all] Search for other: Achondrites, Eucrites, and HED achondrites | ||||||||||||||||||||||||
Writeup![]() |
Writeup from AMN 6(1):
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. | ||||||||||||||||||||||||
Data from: MB76 Table 2 Line 534: |
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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:![]() |
Statistics: This is 1 of 43700 approved meteorites from Antarctica (plus 3802 unapproved names) | ||||||||||||||||||||||||
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