Geology Reference
In-Depth Information
Ungrouped chondrite
192.77 g
Found January 7, 1989
8.5 × 4.5 × 3.0 cm
Weathering = Be
diversity of materials outside the established groups. Chondrites that have
been ungrouped in the past have eventually led to the establishment of
robust groups (like Renazzo [CR], Karoonda [CK], and Rumuruti [R]
chondrites). Ungrouped chondrites constantly push the boundaries of
classification and keep our classification schemes in check.
10
17
Cl
8
6
10
0.8
CM
4
CV
7
2
MAC88107
0.5
R
CO
0
0.4
5
CK
0.3
-2
CR
-4
CO whole-rock
3
CM whole-rock
C2 ungrouped
-6
-8
2
8
-6
-4
-2
0246810
12
14
16
18
10
20
Al/Mn (atom. ratio)
30
δ
18
O (‰ rel. SMOW)
Plate 18
MiNERALogy
SigNiFiCANCE
MAC 88107 has abundant small chondrules (~0.3 mm in
diameter), numerous mineral aggregates, and mineral
grains set in a black matrix. Most of the chondrules con-
sist of granular olivine (Fa
0.5-39
, with a mean of Fa
8
) and
olivine-pyroxene (Fs
0.8-9
). Accessory amounts of finely
dispersed nickel-iron and sulfide are present.
MAC 88107 represents material that is intermediate in
bulk composition between CM and Co chondrites (right,
[107]) and contains oxygen isotopic variation that also
spans the gaps between Co and CM chondrites (left,
[103]). The infrared spectrum of this sample has also
been compared to spectra of asteroid 1 Ceres, suggesting
that it may represent material like that found on our
largest asteroid.
References [103-108]
