Sample Petrographic Description
Sample Number | ALH 99500 |
Newsletter | 24,1 |
Location | Allan Hills |
Field Number | 12065 |
Dimensions (cm) | 3.0 x 1.5 x 1.5 |
Weight (g) | 13.60 |
Original Classification | CM2 Chondrite |
Pairing | ALH 82100; ALH 82131; ALH 84036; ALH 84039; ALH 84046; ALH 84050; ALH 84053; ALH 90407; ALH 99500; |
Mineral Composition (%Fa & %Fs) | |
Fayalite (mol%): 1-47 | |
Weathering | |
B | |
Fracturing | |
A/B | |
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 Description (,4) - Tim McCoy, Linda Welzenbach | |
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. | |
Notes | |
ALH 82100, ALH 82131, and ALH 84036, ALH 84039, ALH 84046, ALH 84050, ALH 84053, ALH 90407, and ALH 99500 are all from the far western icefield; although they have been paired for many years with ALH 81002, the latter is nearly 80 km away and too far to be reasonably paired given the ice flow regimes in that region. Additionally, available observations suggest ALH 99500 was erroneously paired with ALH 83100 - instead we suggest pairing with ALH 82100. AMN 45 no. 2. |
Antarctic Meteorite Images for Sample ALH 99500 | ||||
Lab Photo(s) : | ||||
Antarctic Meteorite Images for Sample ALH 99500 | ||||
Thin Section Photo(s) : | ||||