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Allan Hills A77191 | |||||||||||||||||||||||||||||||||
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Basic information | Name: Allan Hills A77191 This is an OFFICIAL meteorite name. Abbreviation: ALHA77191 This meteorite may also be called Allan Hills 77191 (ALH 77191) in publications. Observed fall: No Year found: 1977 Country: Antarctica [Collected jointly by ANSMET (US) and NIPR (Japan)] Mass: 642 g | ||||||||||||||||||||||||||||||||
Classification history: |
This is 1 of 6493 approved meteorites (plus 2 unapproved names) classified as H4. [show all] Search for other: H chondrites, H chondrites (type 4-7), Ordinary chondrites, and Ordinary chondrites (type 4-7) | ||||||||||||||||||||||||||||||||
Writeup |
Writeup from AMN 2(1):
This text was reprinted from AMN 2(1) in AMN 4(1). In some cases, it may be an updated version from the original. Sample No.: ALHA77191 Location: Allan Hills Field No.: 77122908 Weight (gms): 642.2 Meteorite Type: H4 Chondrite
Physical Description: This 11.0x7.0x5.0 cm specimen is semi-rounded. However, the B surface is concave. This specimen is extremely weathered, making it difficult to determine the amount of fusion crust present. The W surface has a small area of thin, less than .5 mm thick, fusion crust. The iron oxide staining is semi-glossy and reddish-brown. Parallel fractures, in north-south direction, penetrate the stone. No unweathered material was exposed by cleaving the stone in half; the same reddish-brown oxidation staining that is present on the exterior of the stone penetrates throughout the specimen, with the exception of a few areas, approximately .5 cm in diameter, which are slightly lighter. This specimen is considered by Dr. Cassidy to be one of a group of nineteen samples that are likely to be related.
Petrographic Description: Brian Mason The section shows well-developed chondritic structure, the chondrules ranging from 0.2-1.5 mm in diameter. One granular olivine chondrule on the edge of the section encloses a 0.6 mm elliptical inclusion of nickel-iron and troilite. The chondrules are set in a fine-grained granular matrix consisting largely of olivine and pyroxene, with minor nickel-iron and troilite (nickel-iron in excess: of troilite). Brown limonitic staining pervades the section. Microprobe analyses show olivine (Fa17) and pyroxene (Fs15) of uniform composition. The meteorite is classified as an H4 chondrite. | ||||||||||||||||||||||||||||||||
Data from: MB76 Table 2 Line 154: |
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References: | Published in Antarctic Meteorite Newsletter 2(1) (1979), JSC, Houston Published in Meteoritical Bulletin, no. 76, Meteoritics 29, 100-143 (1994)
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Geography: |
Statistics: This is 1 of 44543 approved meteorites from Antarctica (plus 3802 unapproved names) | ||||||||||||||||||||||||||||||||
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Revision history: |
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