Geology Reference
In-Depth Information
Diogenite
786.87 g
Found January 14, 1992
13.0 × 6.9 × 6.0 cm
Weathering = A/B
Diogenites are orthopyroxenites that also contain chromite, metal, and
rarely olivine. Most common are brecciated diogenites. The diogenites are
thought to represent either pyroxenite cumulates from an early magmatic
system on an asteroid, or partial melt residue. in either case, there has
been subsequent thermal metamorphism producing somewhat uniform
Mg# among the diogenite group.
7
600°C
400°C
300°C
200°C
6
2
Eucrite
Range of
terrestrial
metamorphics
Landes
5
Bondoc
Howardite
Diogenites
Estherville
4
A-L
1
PCA 91077
ALHA 77256
Meteorites
Diogenite
3
Johnstown
LAP 91900
Serra de Magé
cumulate eucrite
LEW 88008
Shalka
Range of
terrestrial
volcanics
Roda
2
Diogenites
Serra de Magé
cumulate eucrite
Johnstown
1.46
1.50
1.54
1.58
1.62
1.66
1.70
0
1 1. 0
2.4
0.3
0.6
0.9
1. 5
Wavelength ( µ m)
1. 2
1. 8
2.1
1.2
1. 4
1.6
1. 8
2.0
2.2
100/T(K)
Plate 58
MiNERALogy
SigNiFiCANCE
LAP 91900 and its pairs contain >99% orthopyroxene,
with minor to trace amounts of clinopyroxene, chromite,
troilite, FeNi metal, and silica.
LAP 91900 has nine paired masses and represents close
to 3 kg of diogenitic material. As such, it has contributed
to evaluating many aspects of diogenite formation such
as magmatic trends of major and trace elements, cooling
rates, and isotopic heterogeneity in the inner solar system.
Early studies utilized LAP 91900 to strengthen the infrared
spectral link to asteroid 4 Vesta (left, [428]). orthopyroxene
crystallographic studies indicate that many diogenites
equilibrated at low temperatures between 300 and 400°C
(right, [431]).
References [428-431]
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