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Allan Hills A81101
Basic information Name: Allan Hills A81101
     This is an OFFICIAL meteorite name.
Abbreviation: ALHA81101
This meteorite may also be called Allan Hills 81101 (ALH 81101) in publications.

Observed fall: No
Year found: 1981
Country: Antarctica [Collected by US Antarctic Search for Meteorites program (ANSMET)]
Mass:help 119.2 g
Antarctic Meteorite Newsletter:  AMN 6(2)  (1983)  Ureilite
Meteoritical Bulletin:  MB 76  (1994)  Ureilite
NHM Catalogue:  5th Edition  (2000)  Ureilite
MetBase:  v. 7.1  (2006)  Ureilite
Recommended:  Ureilite    [explanation]

This is 1 of 617 approved meteorites classified as Ureilite.   [show all]
Search for other: Achondrites, Ureilites
Writeup from AMN 6(2):

Sample No.: ALHA81101

Location: Allan Hills

Field No.: 1634

Weight (gms): 119.2

Meteorite Type: Ureilite


Physical Description: Carol Schwarz

Fusion crust occurs on two sides of this specimen. The other sides have a rough surface, dark brown in color with gray inclusions. The interior is medium gray and not extensively weathered. It appears to be fractured or shocked, having a blocky texture. Dimensions: 7.2 x 4.5 x 3 cm


Petrographic Description: Brian Mason

The section shows an aggregate of subhedral to anhedral crystals of olivine, 1-3 mm across; they are rimmed with dark carbonaceous material. Pyroxene, if present, is in sma1l amount. Accessory nickel-iron is present, as minute grains along grain boundaries and fractures; it is partly altered to brown limonite. Under crossed polars the olivine crystals are seen as a mosaic of tiny grains averaging 0.05 mm across, evidently a shock effect. Microprobe analyses show olivine of variable composition, Fa10-22, mean Fa19. The meteorite is a ureilite; it differs from previously described ureilite from the Allan Hills in the mosaic texture of the olivine.

Data from:
  Table 2
  Line 624:
Origin or pseudonym:Main icefield
Mass (g):119.2
Weathering grade:A/B
Fayalite (mol%):20
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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° 45' 5"S, 159° 20' 1"E)
Note: the NHM and MetBase coordinates are 9.4 km apart

     This is 1 of 43700 approved meteorites from Antarctica (plus 3802 unapproved names)
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