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Allan Hills 84100
Basic information Name: Allan Hills 84100
     This is an OFFICIAL meteorite name.
Abbreviation: ALH 84100
Observed fall: No
Year found: 1984
Country: Antarctica [Collected by US Antarctic Search for Meteorites program (ANSMET)]
Mass:help 110.3 g
Antarctic Meteorite Newsletter:  AMN 9(3)  (1986)  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 9(3):

Sample No.: ALH84100

Location: Allan Hills

Weight (g): 110.3

Field No.: 2800

Dimensions (cm): 7.5 x 3.5 x 3

Meteorite Type: H5 Chondrite with clast


Macroscopic Description,: Roberta Score

Weathered fusion crust covers 60% of this fragment. One striking feature of this stone is the heavily weathered fracture surface which contains a semi-rounded clast, 1.5 x 1.3 x 0.2 cm in dimension. This clast is white to light gray in color and coarse-grained. The interior is moderately weathered (heavy in areas), medium-gray in color, and contains numerous chondrules.


Thin Section (,4; ,5) Description: Brian Mason

Portions of the clast in this H5 chondrite are present in two thin sections (84100,4 from 84100,1 and 84100,5 from 84100,2). The clast consists of granular olivine and pyroxene, with a little plagioclase and trace amounts of nickel-iron. Compositions of olivine (Fa18) and pyroxene (Fs16) are similar to those in the chondritic part of the meteorite; in addition, one grain of pigeonite (Wo9Fs15) was analysed. Two grains of plagioclase (An38, 50) were analysed. The olivine is turbid and shows undulose extinction (possible shock effects).

Data from:
  Table 2
  Line 1065:
Origin or pseudonym:Near Western
Mass (g):110.3
Weathering grade:B
Fayalite (mol%):18
Ferrosilite (mol%):16
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References: Published in Antarctic Meteorite Newsletter 9(3) (1986), 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° 44' 34"S, 158° 50' 1"E)
Note: the NHM and MetBase coordinates are 21.5 km apart

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