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Constituent
SiOp
A12O3
FeO+MnO
MgO
CaO*
KaoO
KoO
Constituent
SiO2 .
A12O3
FeO+MnO
Ma-0
CaO* ....
Na20
KoO
TABLE 4.—Chemical composition of bulk silicates from chemical analyses and of unidentified
fractions "residue" in the modal analyses
Atarra
Silicate
fraction Residue
83%
of total
2U.85S
of total
1*7.5
2.1
16.8
29.8
2.1+
1.2
0.1
Mabwe
Silicate
fraction
82. k%
of total
1+7-3
2.9
17.2
29. k
2.0
1.1
0.1
50.3
6.U
17. h
21.U
0.0
1+.0
0.5
Khojrwa**
Silicate
fraction
83$
of total
1+7.5
2.8
16.7
29.9
2.1
1.2
0.1
Silicate
fraction
85%
of total
1+7-5
2.7
16.9
29.3
1-9
1.2
0.1
Cranganore
Mirzapur
Residue
16.7$
of total
kk.9
2.6
20.7
30.7,
0.0
0.9
0.1
Residue
19-9/5
of total
U8.2
10.0
15.8
21.1
0.0
h.k
0.5
Silicate
fraction
82. k%
of total
1+6.8
2.7
17.1
30.2
1.8
1.1
0.1
Silicate
fraction
82$
of total
i+7.3
2.8
17.3
29.5
1.9
1.2
0.2
Karkh
Segowlie
Residue
19-9$
of total
1+2.2
12.5
16.0
23.6
0.0
5.1
0.6
Residue
20.1J?
of total
51.1
6.7
16.6
22.1+
0.0
2.6
0.5
Silicate
fraction
82$
of total
1+6.8
2.5
18.5
28.5
2.2
1.3
0.2
Silicate
fraction
81+. 5%
of total
Kuttippuram
Sultanpur
*The zero value for calcium in the "residue" is artificial (calculated) because of uncertainties in the amount and
composition of Pyroxene 2, Table 2.
**Residue not determined (see text).
^&S^
*v -v ;?• . W:S
FIGURE 8.—Photomicrograph of thin section of chondritic part
of the Segowlie chondrite (cf., Figure 7). Note the patchy
variation in grain size. Length of section, 3.6 mm.
1+6.9
2.1+
19.1
28.5
1.9
1.1
0.1
TABLE 4.—Silicate composition of eight L- and four H-group
chondrites
Constituent
AI2O3
FeO
MgO
CaO
Na2O
K2O
8 L-Group
Min. Average Max.
46.8
2.1
16.7
28.5
1.8
1.1
0.1
47.2
2.6
17.5
29.4
2.0
1.2
0.1
47.5
2.9
19.1
30.2
2.4
1.3
0.2
*Data fran Fredriksson, et al., 1975
4 H-Group*
Min. Average Max.
47.8
2.4
12.7
30.4
2.2
1.1
0.1
48.7
2.9
13.7
31.0
2.5
1.2
0.1
49.2
3.2
15.4
31.5
tions, e.g., loss of volatiles, and extensive melting
and drop (chondrule) formation because of low
density and high compressibility of the target material.
Later impacts on a parent body caused more
brecciation, destruction of preexisting chondrules
and chondrites, and "solid state" recrystallization
rather than melting and formation of liquid droplets,
i.e., new chondrules, although this must also
have occurred as it did on the moon.
2.7
1.2
0.2
Residue
12.6JS
of total
22.6
2.6
51.3
11+.6
fc.7
3.3
0.9
Residue
19.1$
of total
1+3.8
M
2k.k
21+.7
0.0
1.9
0.3