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| Allan Hills A77021 | |||||||||||||||||||||||||
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| Basic information | Name: Allan Hills A77021 This is an OFFICIAL meteorite name. Abbreviation: ALHA77021 This meteorite may also be called Allan Hills 77021 (ALH 77021) in publications. Observed fall: No Year found: 1977 Country: Antarctica [Collected jointly by ANSMET (US) and NIPR (Japan)] Mass:  16.7 g | ||||||||||||||||||||||||
| Classification history: |
This is 1 of 11568 approved meteorites (plus 23 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 4(1):
Sample No.: ALHA77021 Location: Allan Hills Field No.: 77122744 Weight (gms): 16.65 Meteorite Type: H5 Chondrite
Physical Description: A brownish-black fusion crust covers ~50% of the surface of specimen. The remaining surfaces are fracture surfaces which are severely weathered. The specimen was moderately difficult to chip. Chipping revealed an interior surface that is iron oxide stained. Approximately 2.5 cm long.
Petrographic Description: Brian Mason Chondritic structure well-developed; some chondrules are well-defined, others ark irregular in form and tend to merge-with the groundmass. Chondrules range from 0.3-1.0 mm in diameter, and show a variety of types: granular olivine and olivine-pyroxene, porphyritic olivine with interstitial partly-devitrified glass, barred; olivine, fine-grained pyroxene and others. Fusion crust is present. Yellow-brown limonitic staining is pervasive throughout the section, and some limonite veinlets are present. Microprobe analyses show olivine (Fa18) and orthopyroxene (Fs17) of uniform composition; some small grains of sodic plagioclase were detected. | ||||||||||||||||||||||||
| Data from: MB76 Table 2 Line 28: |
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| References: | Published in Antarctic Meteorite Newsletter 4(1) (1981), 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 44547 approved meteorites from Antarctica (plus 3802 unapproved names) | ||||||||||||||||||||||||
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| Revision history: |
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