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114 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
TABLE 3.—FeO content of olivine grains in two thin sections
as measured on two different days by electron microprobe
Grain
No.
18
23
25
89
95
80
Mean
SECTION 1
Day 1 Day 2
4.48 4.39
4.07 4.10
4.24 4.30
4.04 4.00
4.31 4.30
4.39 4.39
4.26 4.25
Grain
No.
34
36
37
40
41
45
56
62
59
71
Mean
SECTION 10
Day 1 Day 2
3.39 3.31
3.60 3.77
3.79 3.49
3.61 3.57
3.72 3.58
3.86 3.73
3.57 3.36
3.40 3.38
2.98 2.99
3.83 3.73
3.56 3.49
Chemical Composition
Samples of three silicate inclusions, weighing 3.5
(no. 1), 6.7 (no. 2), and 9 (no. 3) grams, respectively,
were taken for chemical analysis. Number 1 was a
surface inclusion, and the location of the other two
is shown in Figure 3. These samples contained
varying amounts of metal as grains dispersed
throughout the silicate matrix and veinlets or protrusions
extending from the main mass of meteorite
into the silicates. Each sample was ground in a
tungsten carbide mill and passed through a 100mesh
sieve to separate coarse metallic particles
from finely ground silicates. Since for this study
analyses of the silicates are of prime interest, only
the fraction less than 100 mesh was used for
analysis. The bulk chemical analysis was performed
in a manner similar to that described earlier
(Jarosewich, 1966). The results are shown in Table
TABLE 4.—Average FeO content of olivine and FeO and CaO content (weight percent) of
orthopyroxene of all thin sections studied
Inclusion:
Section" 1 "
2
2
2:
2 :
1 :
3 : 1
4 : 10.1
10.2
5 :
6 :
8 :
11 :
3.1
3.2
4
9.1
9.2
7
2
5.1
5.2
6.1
6.2
8.1
8.2
11
12. 1*12.1
12. 2*12.2
22
24
47
21
23
14
40
25
17
26
26
31
11
38
24
39
16
32
30
Olivine
FeO
A
3.88 ± 0.10
3.84 ± 0.19
3.75 ± 0.26
3.87 ± 0.21
3.88 ± 0.19
3.98 ± 0.15
4.06 ± 0.25
4.16 ± 0.14
3.54 ± 0.19
3.60 ± 0.17
4.46 ± 0.19
4.62 + 0.17
3.57 ± 0.25
3.56 ± 0.28
3.99 + 0.15
4.00 ± 0.26
3.63 ± 0.17
4.03 ± 0.25
3.66 ± 0.26
n
29
51
96
26
25
32
29
40
34
37
14
27
35
57
39
26
27
40
33
FeO
4.34
4.29
4.51
4.42
4.51
4.24
4.00
Or thopyroxene
A
t 0.25
t 0.36
t 0.31
t 0.19
t 0.30
t 0.35
t 0.36
4.54 : t 0.42
4.24 dt
0.33
4.26 db
0.40
3.98 it
0.30
4.11 dt
0.16
4.60 d 0.23
4.70 = t 0.32
4.32 i^
0.26
4.16 i 0.29
3.85 i 0.23
4.40 i 0.39
4.28 d 0.26
CaO
0.76 ± 0.07
0.77 ± 0.09
0.85
-
A
0.80 ± 0.06
0.82 ± 0.09
0.74 ± 0.10
0.78 ± 0.11
0.90 ± 0.15
0.76 ± 0.14
0.82 ± 0.15
0.69 ± 0.09
0.72 ± 0.08
0.86 ± 0.10
0.94 ± 0.17
0.79 ± 0.07
0.75 ± 0.16
0.73 ± 0.07
0.84 ± 0.13
0.78 ± 0.09
The suffix .1 or .2 following a thin section number means that two different areas in the same section
were probed.
n = number of grains analyzed
A = values giving the standard deviation calculated from the distribution of the £ measurements, not
from counting statistics.
Fa = fayalite Fe~SiO,, mole percent
Fs = ferrosilite FeSiO,, mole percent
*Inclusions 12.1 and 12.2 are two different pieces on section 12.
Fa
3.8
3.7
3.8
4.0
4.0
4.1
3.5
4.5
3.5
4.0
3.6
4.0
3.6
Fs
6.0
6.3
6.2
5.9
5.6
6.4
5.9
5.7
6.6
5.9
5.4
6.2
6.0
Fa/Fs
0.63
0.58
0.61
0.68
0.71
0.64
0.59
0.79
0.53
0.68
0.67
0.64
0.60