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118 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
Constituent
Si0 2
TiO2
A1 2°3
Cr 2°3
FeO ,
MnO
MgO
CaO
Na2O
K20
P 2°5
TABLE 8.—Composition of the silicate portion of inclusions 1-5, compared to chondrites
and mesosiderites
Chemical analysis
2 3 1
53.4
0.14
3.97
0.38
5.75
0.37
32.9
1.27
1.43
0.13
0.30
49.9
0.16
2.02
0.37
4.10
0.38
39.3
3.05
0.58
0.07
0.04
50.8
0.17
1.83
0.13
5.31
0.47
38.5
1.47
0.70
0.05
0.52
Calculated from
the Mode
1 4 5
50.4
0.11
1.8
0.17
3.6*
0.34
41.4
1.3
0.7
0.03
n.d.
54.1
0.12
3.7
0.18
3.4
0.34
35.5
1.1
1.4
0.04
n.d.
48.0
0.08
2.5
0.13
3.8
0.32
42.4
1.35
1.0
0.03
n.d.
Average of
inclusions
1-5
51.2
0.13
2.80
0.24
4.5
0.38
37.7
1.65
1.0
0.08
0.29
Average silicate portion
Chondrites* Mesosi-
H-group L-group derites'*'
47.8
0.16
2.77
0.68
13.84
0.41
30.5
2.28
1.10
0.12
0.35
46.5
0.15
2.59
0.61
17.17
0.39
28.9
2.18
1.12
0.13
0.26
The chemical analyses are from the data of Table 7, recalculated on a metal-, troilite-, carbon-, and
water-free basis. Inclusions 1, 4, and 5 were calculated from the modal composition values of Table 1
and the chemical composition of their minerals determined by electron microprobe.
*from Table 7
+from B.N. Powell (1971)
x This value gives FeO in the silicates only, not FeO due to weathering (Table 1).
n.d. = not determined
TABLE 9.—Composition of silicate inclusions 1-5 and chondrite average from Table 8, recalculated
also without FeO (element ratios are calculated from atom percentages)
Constituent
Si02
TiO2
Al203
Cr203
MnO
MgO
CaO
Na20
K20
P2O5
,
,
TOO Al/Si ..
100 Mg/Si ..
100 Ca/Si ..
100 Ca/Al ..
Chemical Analysis
2 3 1
56.60
0.15
4.21
0.41
0.40
34.90
1.35
1.52
0.14
0.32
29.00
52.00
0.17
2.10
0.38
0.40
41.00
3.18
0.60
0.08
0.04
140.00
53.70
0.18
1.93
0.14
0.50
40.70
1.55
0.74
0.06
0.55
8.80 4.80 4.20
92.00 117.00 113.00
2.60 6.50 3.10
73.00
Calculated from the Mode
1 4 5
52.30
2.00
42.90
1.35
0.75
0.03
4.50
122.00
2.80
62.00
56.00
36.70
1.15
1.50
0.04
28.00
50.00
2.65
44.10
1.40
1.10
0.03
8.00 6.20
98.00 131.00
2.20 3.00
48.00
Average of
inclusions
1-5
53.70
0.17
2.94
0.31
0.43
39.50
1.73
1.10
0.10
0.30
6.50
110.00
3.50
53.00
52.9
0.47
8.74
n.d.
13.51
0.51
14.86
5.67
n.d.
0.01
0.83
H- and L-
Chondrites
Average *
* H- and L-chondrite compositions are so similar on this basis that the average of both groups was taken.
55.80
0.18
3.17
0.76
0.47
35.10
2.63
1.32
0.15
0.36
6.70
94.00
5.00
75.00