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Allan Hills A81100
Basic information Name: Allan Hills A81100
     This is an OFFICIAL meteorite name.
Abbreviation: ALHA81100
This meteorite may also be called Allan Hills 81100 (ALH 81100) in publications.

Observed fall: No
Year found: 1981
Country: Antarctica [Collected by US Antarctic Search for Meteorites program (ANSMET)]
Mass:help 154.6 g
Antarctic Meteorite Newsletter:  AMN 6(2)  (1983)  H5
Meteoritical Bulletin:  MB 76  (1994)  H5
NHM Catalogue:  5th Edition  (2000)  H5
MetBase:  v. 7.1  (2006)  H5
Recommended:  H5    [explanation]

This is 1 of 10803 approved meteorites (plus 19 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 from AMN 6(2):

Sample No.: ALHA81100

Location: Allan Hills

Field No.: 1484

Weight (gms): 154.6

Meteorite Type: H5 Chondrite


Physical Description: Carol Schwarz

This specimen has black fusion crust on all but two sides. It is polygonally fractured and somewhat weathered. The other surfaces are dark reddish brown but show distinct chondrules and gray clasts. The interior is gray with oxidation haloes and a 1-2 mm weathering rind. Dimensions: 5 x 4.8 x 4.8 cm


Petrographic Description: Brian Mason

Chondrules are fairly abundant but their margins are diffuse, tending to merge with the granular groundmass, which consists largely of olivine and pyroxene with minor amounts of nickel-iron and troilite. Weathering is moderate, being limited to brown limonitic staining around metal grains. Microprobe analyses gave the following compositions: olivine, Fa19; orthopyroxene, Fs17. The meteorite is classified as an H5 chondrite.

Data from:
  Table 2
  Line 623:
Origin or pseudonym:Main icefield
Mass (g):154.6
Weathering grade:B
Fayalite (mol%):19
Ferrosilite (mol%):17
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References: Published in Antarctic Meteorite Newsletter 6(2) (1983), JSC, Houston
Published in Meteoritical Bulletin, no. 76, Meteoritics 29, 100-143 (1994)
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     Catalogue of Meteorites:   (76° 43'S, 159° 40'E)
     Recommended::   (76° 43'S, 159° 40'E)

     This is 1 of 43331 approved meteorites from Antarctica (plus 3802 unapproved names)
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