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Allan Hills A78084 | |||||||||||||||||||||||||||||
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Basic information | Name: Allan Hills A78084 This is an OFFICIAL meteorite name. Abbreviation: ALHA78084 This meteorite may also be called Allan Hills 78084 (ALH 78084) in publications. Observed fall: No Year found: 1978 Country: Antarctica [Collected jointly by ANSMET (US) and NIPR (Japan)] Mass: ![]() | ||||||||||||||||||||||||||||
Classification history: |
This is 1 of 44 approved meteorites classified as H3.9. [show all] Search for other: H chondrites, H chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3) | ||||||||||||||||||||||||||||
Writeup![]() |
Writeup from AMN 3(3):
This text was reprinted from AMN 3(3) in AMN 4(1). In some cases, it may be an updated version from the original. Sample No.: ALHA78084 Location: Allan Hills Field No.: 270 Weight (gms) 14280.0 Meteorite Type: H3 Chondrite
Physical Description: This is a complete specimen with splotchy brown and black fusion crust covering the entire meteorite. Several large fractures penetrate the interior of the stone. A thin white deposit was evident along some of these cracks after the meteorite was dried. Many light colored rounded and irregular inclusions are apparent on the cut faces, some as large as 4 mm in diameter. Metal is visible though most of the metal have halos around them, giving the cut faces a marbled look of small fresh areas and large oxidized areas.
Petrographic Description: Brian Mason The section shows a close-packed aggregate of chondrules, 0.3-1.2 mm in diameter, and a few angular enclaves (some are chondrule fragments), in a minor amount of fine-grained matrix. A wide variety of chondrules is present, the commonest being porphyritic olivine and olivine-pyroxene with interstitial glass; some of the glass is brown and transparent, but much of it is turbid and partly devitrified. The pyroxene is polysynthetically twinned clinobronzite. The matrix contains a considerable amount of fine-grained nickel-iron and a lesser amount of troilite. Weathering is extensive, with veins and patches of brown limonite throughout the section. Microprobe analyses show olivine of rather uniform composition, averaging Fa18, and pyroxene of variable composition, Fs8-24, average Fs13. The mean composition of the olivine and the amount of nickel-iron indicate H group and the meteorite is classified as an H3 chondrite. | ||||||||||||||||||||||||||||
Data from: MB76 Table 2 Line 315: |
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References: | Published in Antarctic Meteorite Newsletter 3(3) (1980), JSC, Houston Published in Meteoritical Bulletin, no. 76, Meteoritics 29, 100-143 (1994)
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Geography:![]() |
Statistics: This is 1 of 43700 approved meteorites from Antarctica (plus 3802 unapproved names) | ||||||||||||||||||||||||||||
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