MetSoc Home            Publications            Contacts  
Search the Meteoritical Bulletin Database
Last update: 6 Aug 2022
Search for: Search type: Search limits: Display: Publication:
Text help
Starts with
Sounds like
Falls  Non-NWAs
What's new
  in the last:
Limit to approved meteorite names
Search text:  
Allan Hills A81022
Basic information Name: Allan Hills A81022
     This is an OFFICIAL meteorite name.
Abbreviation: ALHA81022
This meteorite may also be called Allan Hills 81022 (ALH 81022) in publications.

Observed fall: No
Year found: 1981
Country: Antarctica [Collected by US Antarctic Search for Meteorites program (ANSMET)]
Mass:help 913 g
Antarctic Meteorite Newsletter:  AMN 6(1)  (1983)  H4
Meteoritical Bulletin:  MB 76  (1994)  H4
NHM Catalogue:  5th Edition  (2000)  H4
MetBase:  v. 7.1  (2006)  H4
Recommended:  H4    [explanation]

This is 1 of 6359 approved meteorites (plus 2 unapproved names) classified as H4.   [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.: ALHA81022

Location: Allan Hills

Field No.: 1482

Weight (gms): 912.5

Meteorite Type: H4 Chondrite

Physical Description: Roberta Score

The bottom surface shows relief with many chondrules apparent. All other surfaces are covered with a thin dull black fusion crust. This stone was extremely hard to chip. The small piece that fell off revealed an evenly weathered interior with several inclusions visible. Dimensions: 11.5 x 10 x.5.5 cm.


Petrographic Description: Brian Mason

The section shows a close-packed aggregate of chondrules and chondrule fragments, up to 2.5 mm across, with interstitial fine-grained matrix. A wide variety of chondrule types is present, the commonest being porphyritic olivine, granular olivine and olivine-pyroxene, barred olivine, and fine-grained radiating pyroxene. Some intergranular glass within the chondrules is pale brown and transparent, but is usually turbid and partly devitrified. Much of the pyroxene is polysynthetically twinned clinobronzite. Small areas of brown limonite are concentrated around the margins of the section. Microprobe analyses show olivine (Fa19) and pyroxene (Fs17) of essentially uniform composition (% mean deviation FeO 2-3). The texture is similar to that of type 3 chondrites, but the homogeneous nature of the olivine and pyroxene indicates type 4; the meteorite is classified as an H4 chondrite. It closely resembles ALHA78084 (recently reclassified from H3 to H4), with which it is tentatively paired.

Data from:
  Table 2
  Line 545:
Origin or pseudonym:Middle Western
Mass (g):912.5
Weathering grade:B/C
Fayalite (mol%):19
Ferrosilite (mol%):17
Comments:26Al=44±2; 77009 pairing group
Search for specimens in the Smithsonian Institution collection (U.S.):   
    Require SI photo
Search for this meteorite in the NASA/JSC database (U.S.):   
References: Published in Antarctic Meteorite Newsletter 6(1) (1983), JSC, Houston
Published in Meteoritical Bulletin, no. 76, Meteoritics 29, 100-143 (1994)
Find references in NASA ADS:
Find references in Google Scholar:

     Catalogue of Meteorites:   (76° 43'S, 159° 40'E)
     Recommended::   (76° 49' 43"S, 158° 13' 31"E)
Note: the NHM and MetBase coordinates are 38.9 km apart

     This is 1 of 43352 approved meteorites from Antarctica (plus 3802 unapproved names)
Proximity search:
Find nearby meteorites: enter search radius (km):

Direct link to this page