Geology Reference
In-Depth Information
CB
a
chondrite
39.6 g
Found December 14, 1994
3.2 × 2.1 × 1.4 cm
Weathering = B
chondrites. They contain high modal contents of metal, as well as CAis
and chondrules. Between the coarser-grained components is a thin layer
of intimately intermixed glass and metallic quench liquids that formed
upon shock of the meteorite. The hydrated matrix that is found in most
other carbonaceous chondrites is largely missing; the only remnant is
interstitial glass and very rare hydrated clasts. CB
a
chondrites are gener-
ally fine grained in texture with ~100 μm chondrules and metal grains.
Ni,
Co,
Cr,
11
10
9
8
7
6
5
0.4
0.3
0.2
0.1
0.0
0 0 0 0 120
Distance (
µ
m)
150
180
210
240
Plate 21
MiNERALogy
SigNiFiCANCE
Zoned FeNi grains, CAis, small cryptocrystalline chon-
drules, and fine-grained interstitial shock melt.
QUE 94411 was the first bencubbinite recovered from
Antarctica and has been the subject of intense study,
especially on the origin of the zoned metal grains (zoned
w.r.t. all siderophile elements, including PgEs) (right,
[129]), and a weak foliation (left, [129]) attributed to
shock.
References [126-130]
