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Allan Hills A81099
Basic information Name: Allan Hills A81099
     This is an OFFICIAL meteorite name.
Abbreviation: ALHA81099
This meteorite may also be called Allan Hills 81099 (ALH 81099) in publications.

Observed fall: No
Year found: 1981
Country: Antarctica [Collected by US Antarctic Search for Meteorites program (ANSMET)]
Mass:help 151.6 g
Antarctic Meteorite Newsletter:  AMN 6(2)  (1983)  L6
Meteoritical Bulletin:  MB 76  (1994)  L6
NHM Catalogue:  5th Edition  (2000)  L6
MetBase:  v. 7.1  (2006)  L6
Recommended:  L6    [explanation]

This is 1 of 12162 approved meteorites (plus 7 unapproved names) classified as L6.   [show all]
Search for other: L chondrites, L chondrites (type 4-7), Ordinary chondrites, and Ordinary chondrites (type 4-7)
Writeup from AMN 6(2):

Sample No.: ALHA81099

Location: Allan Hills

Field No.: 1284

Weight (gms): 151.6

Meteorite Type: L6 Chondrite


Physical Description: Carol Schwarz

This angular piece is covered with black fusion crust. Oxidation halos and white deposit are present. The interior is light gray with some darker inclusions. A few oxidation halos occur. Dimensions: 7 x 3 x 3 cm


Petrographic Description: Brian Mason

Chondrules are sparse and poorly defined, tending to merge with the granular groundmass, which consists largely of olivine and pyroxene, with minor amounts of plagioclase, nickel-iron, and troilite. Remnants of fusion crust, up to 0.6 mm thick, rim part of the section. Weathering is minor, being limited to brown limonitic staining around metal grains. Microprobe analyses gave the following compositions: olivine, Fa25; orthopyroxene, Fs21; plagioclase, An10. The meteorite is an L6 chondrite.

Data from:
  Table 2
  Line 622:
Origin or pseudonym:Near Western
Mass (g):151.6
Weathering grade:A/B
Fayalite (mol%):25
Ferrosilite (mol%):21
Comments:26Al=80±4; NTL=2.6±0.1
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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' 54"S, 158° 48' 26"E)
Note: the NHM and MetBase coordinates are 22.1 km apart

     This is 1 of 43499 approved meteorites from Antarctica (plus 3802 unapproved names)
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