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Allan Hills A81020
Basic information Name: Allan Hills A81020
     This is an OFFICIAL meteorite name.
Abbreviation: ALHA81020
This meteorite may also be called Allan Hills 81020 (ALH 81020) in publications.

Observed fall: No
Year found: 1981
Country: Antarctica [Collected by US Antarctic Search for Meteorites program (ANSMET)]
Mass:help 1353 g
Antarctic Meteorite Newsletter:  AMN 6(1)  (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 10605 approved meteorites (plus 18 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(1):

Sample No.: ALHA81020

Location: Allan Hills

Field No.: 1492

Weight (gms): 1352.5

Meteorite Type: H5 Chondrite


Physical Description: Carol Schwarz

ALHA81020 is almost totally covered by a thin, black, polygonally fractured fusion crust. White deposits have formed on one surface. The interior is light gray in color with numerous oxidation haloes. Some fresh metal is obvious. Small white clasts, 1-2 mm, occur in the matrix. Dimensions: 11 x 8 x 7 cm.


Petrographic Description: Brian Mason

Chondrules are present, ranging up to 2.2 mm across, but most of the section shows a granular aggregate of olivine and pyroxene with minor amounts of nickel-iron and troilite. Weathering is moderate, being limited to brown limonitic staining around metal grains. A little fusion crust is present on one edge. Microprobe analyses give the following compositions: olivine, Fa19; orthopyroxene, Fs16. The meteorite is classified as an H5 chondrite.

Data from:
  Table 2
  Line 543:
Origin or pseudonym:Main icefield
Mass (g):1352.5
Weathering grade:Be
Fayalite (mol%):19
Ferrosilite (mol%):16
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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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     Catalogue of Meteorites:   (76° 43'S, 159° 40'E)
     Recommended::   (76° 41' 36"S, 159° 4' 36"E)
Note: the NHM and MetBase coordinates are 15.4 km apart

     This is 1 of 41899 approved meteorites from Antarctica (plus 3802 unapproved names)
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