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Allan Hills A77208 | |||||||||||||||||||||||||
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Basic information | Name: Allan Hills A77208 This is an OFFICIAL meteorite name. Abbreviation: ALHA77208 This meteorite may also be called Allan Hills 77208 (ALH 77208) in publications. Observed fall: No Year found: 1977 Country: Antarctica [Collected jointly by ANSMET (US) and NIPR (Japan)] Mass: 1733 g | ||||||||||||||||||||||||
Classification history: |
This is 1 of 6484 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 1(3):
This text was reprinted from AMN 1(3) in AMN 4(1). In some cases, it may be an updated version from the original. Sample No.: ALHA77208 Location: Allan Hills Field No.: 77122904 Weight (gms): 1733.0 Meteorite Type: H4 Chondrite
Physical Description: The specimen is angular, highly fractured, and severely weathered. No fusion crust remains on the specimen. The fractures appear to penetrate throughout the stone. Numerous inclusions are visible on the brown weathered surfaces. Approximate dimensions: 13.75x10x9 cm. No fresh metal or unweathered surface was exposed when obtaining material for a thin section.
Petrographic Description: Brian Mason Chondrules are numerous and well-developed, ranging from 0.3 to 0.9 mm in diameter; a variety of types is present, the commonest being granular olivine, porphyritic olivine, and fine-grained or granular pyroxene. Much of the granular pyroxene is polysynthetically twinned clinobronzite. Minor amounts of nickel-iron (~15%) and troilite (~5%) are distributed throughout the groundmass. The meteorite is extensively weathered, with limonite pervading the section and also concentrated in veinlets. Microprobe analyses show olivine (Fa17) and pyroxene (Fs14) of essentially uniform composition. The uniform olivine and pyroxene composition and the presence of clinobronzite indicate that the meteorite should be classified as an H4 chondrite. | ||||||||||||||||||||||||
Data from: MB76 Table 2 Line 165: |
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Catalogs: |
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References: | Published in Antarctic Meteorite Newsletter 1(3) (1978), JSC, Houston Published in Meteoritical Bulletin, no. 76, Meteoritics 29, 100-143 (1994)
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Geography: |
Statistics: This is 1 of 44400 approved meteorites from Antarctica (plus 3802 unapproved names) | ||||||||||||||||||||||||
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Revision history: |
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