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Allan Hills A77230 | |||||||||||||||||||||||||
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Basic information | Name: Allan Hills A77230 This is an OFFICIAL meteorite name. Abbreviation: ALHA77230 This meteorite may also be called Allan Hills 77230 (ALH 77230) in publications. Observed fall: No Year found: 1977 Country: Antarctica [Collected jointly by ANSMET (US) and NIPR (Japan)] Mass: 2.47 kg | ||||||||||||||||||||||||
Classification history: |
This is 1 of 2060 approved meteorites (plus 5 unapproved names) classified as L4. [show all] Search for other: L chondrites, L 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.: ALHA77230 Location: Allan Hills Field No.: 77122703 Weight (gms): 2473.3 Meteorite Type: L4 Chondrite
Physical Description: This is a subrounded to angular specimen which is nearly a complete stone. A brownish-black fusion crust, approximately .5 to 1 mm thick, covers the specimen, with the exception of small broken surfaces. The portion of the fusion crust that was in contact with the ice has an iridescent-like sheen. The specimen has several surface fissures. The specimen was difficult to chip for thin section material. Snow was present along fissures on the interior of the stone. The surface of the meteorite that was in contact with the ice was more severely weathered than the uppermost portion. Weathering is along fissures to a depth of ~5 mm.
Petrographic Description: Brian Mason The section shows a closely-packed aggregate of chondrules, some spherical, but many appear fragmented and broken. A variety of chondrule types are present: barred olivine, porphyritic olivine, fine-grained pyroxene, etc. Chondrule size ranges from 0.3 to 1.0 mm; interstitial material in some chondrules is turbid devitrified glass. Some pyroxene shows polysynthetic twinning. Minor subequal amounts of troilite and nickel-iron are present. A moderate amount of limonitic staining pervades the section. Fusion crust is present on one edge. Microprobe analyses show olivine of fairly uniform composition (Fa22-Fa25, average Fa23) and pyroxene averaging Fs21. | ||||||||||||||||||||||||
Data from: MB76 Table 2 Line 185: |
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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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