Geology Reference
In-Depth Information
L3.0 chondrite
452.6 g
Found December 27, 1997
9.0 × 5.0 × 5.5 cm
Weathering = A
interesting features due to their unequilibrated nature. Because the level of
postnebular thermal heating is low, many minerals and chemical features
are preserved in these samples, making them a treasure trove of astroma-
terials. Presolar grains, pristine chondrules, isotopic heterogeneities, and
organic compounds are among the rare components preserved in
low-grade chondrites.
10
-2
1
2
4
10
-3
3
Previous oxides
10
-4
Previous silicates
Al
2
O
3
Spinel
Hibonite
Ti oxide
10
-5
10
-5
10
-4
10
-3
10
-2
18
O/
16
O
Plate 4
MiNERALogy
SigNiFiCANCE
QUE 97008 exhibits numerous large, well-defined chon-
drules (up to 2 mm) in a black matrix of fine-grained sili-
cates, metal and troilite. Weak shock effects are present.
Polysynthetically twinned pyroxene is extremely abun-
dant. Silicates are unequilibrated with olivines ranging
from Fa
3-33
and pyroxenes from Fs
3-21
.
QUE 97008 preserves presolar grains of all four types:
groups 1 and 3 form in red giant stars, and groups 2 and
4 form in low-mass asymptotic giant branch (AgB) stars
(left, [21]). its pristine chondrues have been used to define
textbook examples of porphyritic and granular chon-
drules (right, [19]). The preservation of organic matter, as
well as high δD ratios has been highlighted in survey
studies of chondrite types.
References [16-23]
