USGS

Table 1. Chemical analyses of rocks from the Harpers Ferry quadrangle, Virginia, Maryland, and West Virginia.
[Numbers 1-31 refer to chemical sample locations shown on plate 1. All analyses were done in the laboratories of the U.S. Geological Survey. Major elements determined by X-ray spectroscopy by D.F. Siems and J.E. Taggart. Minor and rare earth elements determined by instrumental neutron activation analysis by G.A. Wandless and J. Grossman. See Southworth 1991a for field and lab numbers of samples]

Middle Proterozoic
basement rocks

Late Proterozoic
metadiabase dikes (Zmd)

Late Proterozoic metarhyolite dike (Zrd)
Garnet
monzogranite
(Ygt)
Biotite
gneiss
(Ybg)
Hornblende
gneiss
(Yhg)











1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
SiO2
70.8
69.8
66.8
71.7
63.7

48.8
50.5
47.6
50.1
48.4
50.5
49.3
45.8
49.5
44.6

72.7
Al2O3
15.1
15.2
14.7
13.9
15.4

13.3
12.6
13.7
13.5
13.5
13.1
13.7
12.6
13.3
16.9

13.4
Fe2O3
.61
2.12
1.16
.96
4.39

3.44
4.86
3.76
2.6
2.86
3.23
3.77
3.84
14.9
6.1

1.18
FeO
1.8
1.1
3.1
1.4
0.95

9.6
9.4
9.4
10.0
10.4
9.7
8.3
11.5
-
5.0

1.3
MgO
.63
.39
1.0
.71
3.1

5.83
4.36
6.29
6.14
6.38
4.16
6.18
5.67
.96
4.96

.38
CaO
1.35
3.32
3.06
1.79
3.72

9.59
8.73
9.54
8.80
9.54
9.39
9.58
9.56
9.48
18.4

<.02
Na2O
3.56
4.40
2.45
3.00
2.78

2.44
2.24
3.13
2.39
2.99
1.74
3.47
2.63
.83
.84

.75
K2O
4.45
1.60
4.98
4.61
4.94

1.42
.83
.44
.45
.64
.49
.39
1.30
.38
.14

7.35
H2O+
.60
.55
.84
.63
1.2

2.3
2.6
2.5
2.8
2.5
2.9
2.1
1.9
-
1.1

1.4
H2O-
.07
.18
.11
.16
.03

.20
.35
.29
.24
.14
.10
.25
.13
-
.19

.30
TiO2
.26
.30
.73
.35
.93

2.47
2.80
2.29
2.30
2.23
2.74
1.92
3.99
.85
1.20

.36
P2O5
.10
.06
.19
.16
.28

.30
.35
.26
.28
.23
.52
.30
.53
.54
.17

.06
MnO
.04
.05
.05
.03
.06

.20
.22
.19
.21
.22
.20
.20
.24
.20
.16

<.02
CO2
<.01
<.01
.03
.01
.75

<.01
<.01
<.01
.07
<.01
.70
<.01
<.01
-
<.01

<.01
Total
99.38
99.08
99.2
99.41
99.09

99.9
99.85
99.4
99.88
100.04
99.47
99.47
99.7
96.94
99.7

99.23

Table 1. Chemical analyses of rocks from the Harpers Ferry quadrangle, Virginia, Maryland, and West Virginia-Continued.
Late Proterozoic Catoctin Formation metabasalt (Zcm)

Early Jurassic diabase dikes (Jd)
















17
18
19
20
21

22
23
24
25
26
27
28
29
30
31
SiO2
47.9
49.7
47.0
46.2
50.8

50.2
50.4
50.4
50.6
56.0
53.3
48.1
47.6
47.4
47.4
Al2O3
18.3
14.3
14.4
16.0
15.1

15.3
15.2
15.2
15.2
15.2
17.0
15.6
14.6
14.6
14.8
Fe2O3
10.42
9.13
4.52
8.09
9.42

2.45
11.2
11.2
11.3
7.49
11.7
11.2
11.4
11.6
1.98
FeO
4.4
5.2
7.1
6.5
4.4

7.7
-
-
-
-
-
-
-
-
8.3
MgO
5.97
4.37
12.4
5.34
5.36

8.32
8.23
8.06
8.06
4.69
5.76
10.9
13.3
13.1
12.8
CaO
.87
3.92
2.28
6.25
6.64

11.5
11.8
11.9
11.8
5.16
1.95
12.0
11.3
11.3
11.5
Na2O
5.99
1.92
2.60
4.02
1.22

1.86
1.87
1.96
1.98
3.63
5.09
1.60
1.46
1.48
1.46
K2O
1.04
2.62
.04
<.02
<.02

.72
.26
.25
.31
4.16
.13
.32
.31
.28
.29
H2O+
3.2
3.5
5.9
3.5
3.4

.92
-
-
-
-
-
-
-
-
.95
H2O-
.21
.12
.31
.12
.25

.48
-
-
-
-
-
-
-
-
.35
TiO2
.97
3.10
2.23
3.17
2.53

.68
.68
.70
.72
.72
1.10
.29
.27
.27
.27
P2O5
.09
.40
.25
.60
.28

.10
.08
.08
.09
.28
.23
.07
.06
.07
.06
MnO
.28
.21
.34
.22
.20

.18
.18
.18
.18
.10
.15
.17
.18
.17
.17
CO2
<.01
1.2
.19
<.01
<.01

.02
-
-
-
-
-
-
-
-
.21
Total
99.65
99.69
99.56
100.04
99.63

100.43
99.9
99.93
100.24
97.42
96.41
100.25
100.48
100.27
100.54

 

U.S. Geological Survey, U.S. Department of the Interior
This page is https://pubs.usgs.gov/bulletin/b2123/table1.html
Contact: Scott Southworth
Last modified 08.29.00