Newsletter |
15,1 |
Location |
Allan Hills |
Field Number |
6619 |
Dimensions (cm) |
1.0 x 0.9 x 0.6 |
Weight (g) |
0.59 |
Original Classification |
C2 Chondrite |
Updated Classification |
CM2 Chondrite |
Pairing |
ALH 82100;
ALH 82131;
ALH 84036;
ALH 84039;
ALH 84046;
ALH 84050;
ALH 84053;
ALH 90407;
ALH 99500;
|
Fayalite (mol%): 1-31 |
B |
A |
The exterior of this pea-sized meteorite is dark gray to black and contains one small patch of fusion crust. The interior is medium gray. Abundant light colored inclusions and a few small dark inclusions are visible in the coarse grained matrix. |
The section consists almost entirely of black matrix, with sparse chondrules and small scattered grains of olivine. Microprobe analyses show that most of the olivine is near Mg2SiO4 in composition, but some iron-rich grains are present, the range being Fa1-31, mean Fag (CV FeO is 123). The meteorite is a C2 chondrite. |
Many carbonaceous chondrites were initially classified as C2 in early newsletters. These are mostly CM2, based on matrix properties, chondrules abundance and sizes, and therefore all these samples have been reclassified more specifically here as CM2. |
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. |