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| Allan Hills A77223 | |||||||||||||||||||||||||
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| Basic information | Name: Allan Hills A77223 This is an OFFICIAL meteorite name. Abbreviation: ALHA77223 This meteorite may also be called Allan Hills 77223 (ALH 77223) in publications. Observed fall: No Year found: 1977 or 1978 Country: Antarctica [Collected jointly by ANSMET (US) and NIPR (Japan)] Mass:  208 g | ||||||||||||||||||||||||
| Classification history: |
This is 1 of 6000 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 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.: ALHA77223 Location: Allan Hills Field No.: 78012505 Weight (gms): 207.9 Meteorite Type: H4 Chondrite
Physical Description: The T surface of this specimen has patches of dull black fusion crust. The remainder of the sample is stained reddish brown by iron oxidation. The surfaces devoid of fusion crust are fracture surfaces. Several cracks penetrate the sample.
Petrographic Description: Brian Mason Chondritic structure is well developed; chondrules range from 0.2-1.5 mm in diameter, and are of the usual types, the commonest being barred olivine, granular olivine and olivine-pyroxene, and fine-grained pyroxene. The groundmass consists of fine -grained olivine and pyroxene, with minor amounts of nickel-iron and troilite (nickel-iron in excess of troilite). Some of the pyroxene is polysynthetically twinned clinobronzite. The section is extensively veined with red-brown limonite. Microprobe analyses show, olivine of uniform composition (Fa17), and pyroxene of somewhat variable composition (Fs15-Fs23, average Fs17); some analyzed spots within pyroxene grains showed CaO contents up to 15%, suggesting exsolution of diopsidic pyroxene. The meteorite is classified as an H4 chondrite. | ||||||||||||||||||||||||
| Data from: MB76 Table 2 Line 179: |
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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 40719 approved meteorites from Antarctica (plus 4494 unapproved names) | ||||||||||||||||||||||||
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