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Allan Hills A77270 | |||||||||||||||||||||
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Basic information | Name: Allan Hills A77270 This is an OFFICIAL meteorite name. Abbreviation: ALHA77270 This meteorite may also be called Allan Hills 77270 (ALH 77270) in publications. Observed fall: No Year found: 1977 or 1978 Country: Antarctica [Collected jointly by ANSMET (US) and NIPR (Japan)] Mass: ![]() | ||||||||||||||||||||
Classification history: |
This is 1 of 11485 approved meteorites (plus 6 unapproved names) classified as L6. [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.: ALHA77270 Location: Allan Hills Field No.: Y78010502 Weight (gms): 588.9 Meteorite Type: L6 Chondrite
Physical Description: The sample is pyramidal, with the B surface flat, approximately 90% of the specimen is covered with a dull, brownish-black fusion crust, approximately 0.5 mm thick. The surfaces not covered with fusion crust have a weathering rind. The sample has a few fractures. The specimen measures 11.0x7.0x6.0 cm. When obtaining a suitable sample for thin section preparation, whitish-gray matrix material with small metallic flakes was exposed. After the sample was cleaved into halves, it became obvious that weathering along the fractures is severe. In non-fractured areas, the weathering rind penetrates 1 to 3 mm below the fusion crust.
Petrographic Description: Brian Mason The section shows sparse and poorly-defined chondrules, merging with the granular groundmass, which consists of olivine and pyroxene, with minor sub-equal amounts of nickel-iron and troilite; occasional small grains of plagioclase were noted. Fusion crust, up to 0.9 thick, rims part of the section. Limonitic straining and occasional grains of limonite occur in association with nickel-iron grains. Microprobe analyses show olivine (Fa24), orthopyroxene (Fs21), and plagioclase (An11) of uniform composition; a little diopside (Wo46En45Fs9) was noted in association with orthopyroxene. The meteorite is classified as an L6 chondrite. | ||||||||||||||||||||
Data from: MB76 Table 2 Line 221: |
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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 40719 approved meteorites from Antarctica (plus 4494 unapproved names) | ||||||||||||||||||||
Proximity search: |