Geology Reference
In-Depth Information
Ungrouped chondrite
167.535, 110.899 g
Found January 9, 1987
6.0 × 5.0 × 3.5; 5.5 × 5.0 × 3.5 cm
Weathering = B
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.
Fe
Phyllosilicates
ESSEBI
MAC 87300
EET 87770
RENAZZO
IVUNA
ORGUEIL
KABA
Average matrix
1
ESSEBI
80
2
MAC 87300
3
EET 87770
4
RENAZZO
2
60
5
IVUNA
6
ORGUEIL
3
7
4
5
40
1
7
KABA
6
20
65
25
45
45
25
65
Si
Mg
Plate 17
MiNERALogy
SigNiFiCANCE
Chondrules are abundant but small (~0.6 mm across)
and, together with chondrule fragments and mineral
grains, are set in a dark brown to black matrix. Chondrules
consist of granular or porphyritic olivine (almost pure
Mg
2
Sio
4
, but mean composition is Fa
7
) and olivine-
pyroxene (Fs
1-9
); mineral grains are mainly olivine.
MAC 87300 (and 87301) represents carbonaceous chon-
drite material that does not fall into an established carbo-
naceous chondrite group but has Fe-rich matrix and
evidence for hydration. it is an ungrouped C2 chondrite
that provides evidence for aqueous alteration (right,
[102]) on a parent body that differed from the more
common (in our collections) CM2 parent body.
References [99-102]
