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Allan Hills A81025 | |||||||||||||||||||||||||
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Basic information | Name: Allan Hills A81025 This is an OFFICIAL meteorite name. Abbreviation: ALHA81025 This meteorite may also be called Allan Hills 81025 (ALH 81025) in publications. Observed fall: No Year found: 1981 Country: Antarctica [Collected by US Antarctic Search for Meteorites program (ANSMET)] Mass: 379 g | ||||||||||||||||||||||||
Classification history: |
This is 1 of 62 approved meteorites classified as L3.6. [show all] Search for other: L chondrites, L chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3) | ||||||||||||||||||||||||
Writeup |
Writeup from AMN 6(1):
Sample No.: ALHA81025 Location: Allan Hills Field No.: 1598 Weight (gms): 379.0 Meteorite Type: LL3 Chondrite
Physical Description: Roberta Score Although ALHA81025 is extremely weathered, many clasts, both rounded and irregular, are apparent on the exterior. One notable exterior clast is 7 x 5 mm in diameter. The bottom surface is iridescent brown and covered with squall-like marks. The interior is extensively weathered. Dimensions: 9.5 x 8 x 4.5 cm.
Petrographic Description: Brian Mason The section shows a close-packed aggregate of chondrules and chondrule fragments up to 3.5 mm across; in a fine-grained matrix of olivine, pyroxene, troilite, and a little nickel-iron. Chondrule types include porphyritic olivine, granular olivine and olivine-pyroxene, barred olivine, and radiating pyroxene. Much of the pyroxene is polysynthetically twinned clinobronzite. Intergranular glass is present in the chondrules, usually turbid but sometimes transparent and purple-brown. Weathering is extensive, with small areas of brown limonite throughout the section. Microprobe analyses show that olivine and pyroxene have variable composition. Olivine composition ranges from Fa1 to Fa41, with a mean of Fa18 (per cent mean deviation FeO is 76). Pyroxene composition ranges from Fs3 to Fs40, with a mean of Fs15 (per cent mean deviation FeO is 75). Purple glass in a chondrule has the following mean composition (weight per cent): SiO2 56.8, Al2O3 24.1, FeO 3.7, MgO 2.4, CaO 0.4 K2O 4.1, Na2O 8.8, TiO2 1.2, MnO 0.69. The texture and the variable mineral compositions indicate type 3, and the low metal content suggests LL group, hence the meteorite is tentatively classified LL3. It is possibly paired with ALHA79003 (Scott et al., Meteoritics, 17, 65-75, 1982), 81030, 81031, and 81032. | ||||||||||||||||||||||||
Data from: MB76 Table 2 Line 548: |
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Catalogs: |
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References: | Published in Antarctic Meteorite Newsletter 6(1) (1983), JSC, Houston Published in Meteoritical Bulletin, no. 76, Meteoritics 29, 100-143 (1994)
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Geography: |
Statistics: This is 1 of 44543 approved meteorites from Antarctica (plus 3802 unapproved names) | ||||||||||||||||||||||||
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Revision history: |
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