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Allan Hills A81009 | |||||||||||||||||||||||||
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Basic information | Name: Allan Hills A81009 This is an OFFICIAL meteorite name. Abbreviation: ALHA81009 This meteorite may also be called Allan Hills 81009 (ALH 81009) in publications. Observed fall: No Year found: 1981 Country: Antarctica [Collected by US Antarctic Search for Meteorites program (ANSMET)] Mass: ![]() | ||||||||||||||||||||||||
Classification history: |
This is 1 of 391 approved meteorites classified as Eucrite-pmict. [show all] Search for other: Achondrites, Eucrites, and HED achondrites | ||||||||||||||||||||||||
Writeup![]() |
Writeup from AMN 6(1):
Sample No.: ALHA81009 Location: Allan Hills Field No.: 1500 Weight (gms): 229.0 Meteorite Type: Eucrite
Physical Description: Roberta Score ALHA81009 is completely covered with flow marked black fusion crust. Contained in the light-gray matrix are numerous clasts which are as large as .5 cm in diameter. Oxidation haloes are present. Dimensions: 7 x 5.5 x 3.5 cm.
Petrographic Description: Brian Mason The section consists largely of brown grains of pigeonite up to 1 mm and colorless grains of plagioclase up to 2 mm in a comminuted groundmass of these minerals. Some lithic clasts, up to 3 mm across, are present; most are fine-grained, but a few have coarse gabbroic textures. No evidence of weathering is visible. Microprobe analyses show pyroxene compositions ranging fairly continuously from Wo4En33Fs63 to Wo40En26Fs30; En content shows a limited range (28-37) except for one grain Wo6En47Fs47. Plagioclase composition range is An75-93, mean An86. The meteorite is a eucrite, but it differs from previously described polymict eucrites from the Allan Hills in the range and distribution of pyroxene compositions.
[From AMN 7(1):] ALHA81009 Clasts Several interesting clasts were discovered while processing ALHA81009 (Eucrite). They are now available for allocation. 1) Dark clast with light inclusions; 2) Light gray clast with white and yellowish minerals; 3) Gray area with no clasts. Requests for these specific clasts may be made to the MWG. | ||||||||||||||||||||||||
Data from: MB76 Table 2 Line 532: |
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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 43700 approved meteorites from Antarctica (plus 3802 unapproved names) | ||||||||||||||||||||||||
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