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Allan Hills 99500
Basic information Name: Allan Hills 99500
     This is an OFFICIAL meteorite name.
Abbreviation: ALH 99500
Observed fall: No
Year found: 1999
Country: Antarctica [Collected by US Antarctic Search for Meteorites program (ANSMET)]
Mass:help 13.6 g
NHM Catalogue:  5th Edition  (2000)  CM2
Antarctic Meteorite Newsletter:  AMN 24(1)  (2001)  CM2
Meteoritical Bulletin:  MB 85  (2001)  CM2
MetBase:  v. 7.1  (2006)  CM2
Recommended:  CM2    [explanation]

This is 1 of 614 approved meteorites classified as CM2.   [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 2), CM chondrites, and CM-CO clan chondrites
Writeup from AMN 24(1):
Sample No.: ALH 99500
Location: Allan Hills
Field No.: 12065
Dimensions (cm):   3.0x1.5x1.5
Weight (g): 13.596
Meteorite Type: CM2 Chondrite

Macroscopic Description: Kathleen McBride
60% of the exterior of this carbonaceous chondrite has fractured purplish black fusion crust. The exposed interior appears to have a greenish tint. The matrix is made up of soft, chalky black material that has a sulfurous odor. Contained within the matrix are tiny white chondrules.

Thin Section (, 4) Description: Tim McCoy and Linda Welzenbach

ALH 99500 - Plane-Polarized Light ALH 99500 - Cross-Polarized Light
Plane-Polarized Light Cross-Polarized Light
The section consists almost entirely of Fe-rich serpentine, which forms the matrix of the meteorite and has replaced the bulk of most chondrules. A few scattered anhydrous silicates remain. Olivine ranges from Fa1-47, with many Fa0-1. The meteorite is a CM2 chondrite. Pairing with ALH 83100 should be considered.

Data from:
  Table A1
  Line 13:
Origin or pseudonym:Far Western
Mass (g):13.6
Weathering grade:B
Fayalite (mol%):1-47
Comments:83100 pairing group
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References: Published in Antarctic Meteorite Newsletter 24(1) (2001), JSC, Houston
Published in Meteoritical Bulletin, no. 85, MAPS 36, A293-A322 (2001)
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Photographs from AMN:
Photograph from unknown source A photo is in the write-up above
Photos from the Encyclopedia of Meteorites:
Dr Carlton Allen, JSC-KT, NASA      

     Catalogue of Meteorites:   (76° 43'S, 159° 40'E)
     Recommended::   (76° 43'S, 159° 40'E)

     This is 1 of 43500 approved meteorites from Antarctica (plus 3802 unapproved names)
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