Geology Reference
In-Depth Information
CM1 chondrite
40.585 g
Found December 17, 2000
4.5 × 2.5 × 3.5 cm
Weathering = Be
CM carbonaceous chondrites are perhaps the most abundant kind of CCs
and have been at the center of many studies focused on aqueous alteration
on their parent bodies, and on the abundance and species of organic
matter. Alteration postdates primary features such as chondrules and
CAis, producing some impressive textures in CM2 chondrites. CM1 chon-
drites are rarer and provide evidence for the most extreme aqueous alter-
ation known on asteroids.
100%
Mg-Serpentine
Fe-cronstedtite
90 %
Metal
80 %
Pyrrhotite
70 %
Pentlandite
60 %
Magnetite
MET 01070
Gypsum
50 %
Calcite
40 %
Enstatite
30 %
Fo40 (olivine)
20 %
Fo60 (olivine)
Fo80 (olivine)
10 %
Fo90 (olivine)
0%
Forsterite
(olivine)
Plate 14
MiNERALogy
SigNiFiCANCE
Mg-rich serpentine (61%), Fe-rich cronstedtite (26%),
sulfide (2%), magnetite (2%), calcite (2%), olivine (7%;
Fa
0-10
).
CM1 chondrites are rare and almost exclusively defined
by Antarctic samples. Even so, there are many very small
Antarctic samples (<5 g), so larger samples like MET
01070 can be studied by more scientists using more tech-
niques than most of the samples in the collection. The
fine-grained nature of CM1s has led to the development
and application of micro x-ray diffraction analysis to
identify the major mineralogy of samples (right, [66]).
Discovery that MET 01070 represents a most aqueously
altered member of the CM groups, as well as its unique
amino acid content, makes it precious scientific material.
Reference [64-71]
