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Allan Hills A77254 | |||||||||||||||||||||
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Basic information | Name: Allan Hills A77254 This is an OFFICIAL meteorite name. Abbreviation: ALHA77254 This meteorite may also be called Allan Hills 77254 (ALH 77254) in publications. Observed fall: No Year found: 1977 Country: Antarctica [Collected jointly by ANSMET (US) and NIPR (Japan)] Mass: ![]() | ||||||||||||||||||||
Classification history: |
This is 1 of 8504 approved meteorites (plus 4 unapproved names) classified as L5. [show all] Search for other: L chondrites, L 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.: ALHA77254 Location: Allan Hills Field No.: 77122704 Weight (gms): 245.8 Meteorite Type: L5 Chondrite
Physical Description: Very thin, dull, black fusion crust is present on two surfaces (T&N) of the meteorite. The surfaces are free of fusion crust, have a dull, orangish-brown weathering patina, with the exception of the B surface, which is a shiny orangish-brown. From field photographs it was determined that this angular specimen had its B surface in contact with the ice at the time of recovery. The B surface has slickensides. The specimen is 10.5x5.0x4.0 cm. Many inclusions are visible on the sawed surface of the meteorite, which range to as much as 1 cm in length. Discoloration, due to weathering, of the outer most material was observed to a depth of approximately 1.5 cm along the S surface.
Petrographic Description: Brian Mason The section shows well-developed chondritic structure, the chondrules ranging from 0.3-2.1 mm in diameter; a variety of types is present, the commonest being barred olivine, granular olivine and olivine-pyroxene, and radiating pyroxene. The chondrules are set in a granular matrix of olivine and orthopyroxene, with minor subequal amounts of nickel-iron and troilite. Limonitic staining and a few patches of red-brown limonite are associated with the metal grains. Fusion crust is present along one edge of the section. Microprobe analyses show olivine (Fa23) and orthopyroxene (Fs20) of essentially uniform composition. The meteorite is classified as an L5 chondrite. | ||||||||||||||||||||
Data from: MB76 Table 2 Line 205: |
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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 43700 approved meteorites from Antarctica (plus 3802 unapproved names) | ||||||||||||||||||||
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