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| Allan Hills A77012 | |||||||||||||||||||||||||
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| Basic information | Name: Allan Hills A77012 This is an OFFICIAL meteorite name. Abbreviation: ALHA77012 This meteorite may also be called Allan Hills 77012 (ALH 77012) in publications. Observed fall: No Year found: 1977 Country: Antarctica [Collected jointly by ANSMET (US) and NIPR (Japan)] Mass:  180.2 g | ||||||||||||||||||||||||
| Classification history: |
This is 1 of 10853 approved meteorites (plus 19 unapproved names) classified as H5. [show all] Search for other: H chondrites, H chondrites (type 4-7), Ordinary chondrites, and Ordinary chondrites (type 4-7) | ||||||||||||||||||||||||
| Writeup |
Writeup from AMN 3(1):
This text was reprinted from AMN 3(1) in AMN 4(1). In some cases, it may be an updated version from the original. Sample No.: ALHA77012 Location: Allan Hills Field No.: 77122942 Weight (gms): 180.2 Meteorite Type: H5 Chondrite
Physical Description: The sample is roughly pyramidal in shape, with the E surface being semi-flat and a fracture surface. The B and S surfaces have very thin, patchy, black fusion crust. The remainder of the sample is stained reddish-brown by iron oxidation. No unweathered material was exposed during processing.
Petrographic Description: Brian Mason Chondritic structure is well developed; chondrules are 0.3-0.9 mm in diameter, the commonest types being granular olivine, barred olivine, and fine-grained pyroxene. In the olivine chondrules the material interstitial to the olivine is a fine-grained aggregate probably of pyroxene and plagioclase. Some larger irregular aggregates of granular olivine (up to 6 mm in greatest dimension) are present. The matrix of the chondrules and aggregates is a granular aggregate of olivine pyroxene, with minor nickel-iron and troilite (nickel-iron in excess of troilite). Somewhat eroded fusion crust is present along one edge. The section is pervaded with brown limonitic staining, and small patches and veinlets of limonite are present. Microprobe analyses show uniform olivine (Fa18) and orthopyroxene (Fs16) compositions. The meteorite is classified as an H5 chondrite. | ||||||||||||||||||||||||
| Data from: MB76 Table 2 Line 20: |
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| References: | Published in Antarctic Meteorite Newsletter 3(1) (1980), JSC, Houston Published in Meteoritical Bulletin, no. 76, Meteoritics 29, 100-143 (1994)
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Geography:
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Statistics: This is 1 of 43352 approved meteorites from Antarctica (plus 3802 unapproved names) | ||||||||||||||||||||||||
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