DANVILLE BASIN AND VICINITY, VIRGINIA
Seventeen (17) samples of diabase from one (1) sheet and twelve (12) dikes were collected by two (2) workers in Virginia and analyzed by the U.S. Geological Survey. Laura Cummins of Florida State University contributed seven (7) samples from seven (7) dikes for which partial chemistry,is here provided. The balance of the chemistry (major- and selected trace-elements) available for these and many other dikes in this area is documented by Cummins (1987). Froelich and Gottfried collected five (5) samples from the Renan sheet of the Danville basin, the southernmost known quartz-normative diabase sheet in the province, and five (5) samples from five (5) different dikes for which complete chemistry is documented here. The Renan sheet and nine (9) of the ten (10) dikes samples are representative of the high Fe, quartz-normative (HFQ) magma, and one dike is olivine-normative. The very low abundance of platinum (Pt) and palladium (Pd) in the sheet and most of the dikes is characteristic of the HFQ magma elsewhere in the province. The single olivine-normative dike sampled also has unusually low abundances of Pd and especially Pt for rocks of this magma type.
References
Cummins, L.E., 1987, Geochemistry, mineralogy, and origin of
Mesozoic
diabase dikes of Virginia: unpublished Ph.D. thesis, Florida
State
University, Tallahassee, 454 p.
| SAMPLE NO | MAGMA TYPE | DESCRIPTION OF SAMPLES |
|
FG 85 DV-2 |
High Fe, quartz-normative |
Renan sheet - Table
1 |
|
-3 |
|
|
|
-5 |
|
|
|
-6 |
|
chilled margin |
|
-13 |
|
Diabase |
|
FG 85 DV-7 |
High Fe, quartz-normative |
Diabasedikes -
|
|
-8 |
|
|
|
-9 |
|
|
|
-10 |
|
|
|
-11 |
Olivine-normative |
|
|
C-15A-2 |
High Fe, quartz-normative |
Diabase dikes |
|
C-15B-2 |
|
|
|
C-15D-2 |
|
|
|
C-16A-1 |
|
|
|
C-47A-1 |
|
|
|
C-48C-2 |
|
|
|
C-78A-1 |
|
|
| Table 1. Danville basin, Virginia. Renan sheet. | |||||
|
|
W-243400 |
W-243401 |
W-243402 |
W-243403 |
W-243408 |
|
|
FG-85 |
FG-85 |
FG-85 |
FG-85 |
FG-85 |
|
|
DV2 |
DV3 |
DV5 |
DV6 |
DV13 |
|
Lat. |
36°59'N |
36°59'N |
37° 0'N |
37° 0'N |
37° 1'N |
|
Long. |
79° 9'W |
79° 9'W |
79° 9'W |
79° 9'W |
79° 7'W |
|
SiO2 |
53.08 |
52.53 |
52.16 |
52.9 |
52.46 |
|
TiO2 |
1 |
0.94 |
1.06 |
1.01 |
0.93 |
|
A12O3 |
13.9 |
13.67 |
13.57 |
13.8 |
14 |
|
Fe2O3* |
13.2 |
12.83 |
13.56 |
13.19 |
12.87 |
|
MnO |
0.21 |
0.23 |
0.22 |
0.21 |
0.23 |
|
MgO |
6.29 |
6.6ra |
6.31 |
6.26 |
6.73 |
|
CaO |
9.83 |
9.8 |
9.94 |
9.74 |
9.7 |
|
Na2O |
2.42 |
2.2 |
2.39 |
2.31 |
2.27 |
|
K20 |
0.56 |
0.54 |
0.55 |
0.56 |
0.67 |
|
P205 |
0.14 |
0.13 |
0.13 |
0.13 |
0.12 |
|
S |
0.06 |
<0.01 |
0.06 |
0.08 |
0.08 |
|
F |
0.02 |
0.02 |
0.01 |
0.02 |
0.02 |
|
Cl |
0.01 |
0.04 |
<0.00 |
<0.00 |
0.12 |
|
Total |
100.72 |
99.58 |
99.97 |
100.2 |
100.19 |
|
B (ppm) |
10 |
31 |
<1.00 |
17.1 |
- |
|
Sc |
46 |
46 |
45 |
48 |
43 |
|
Cr |
85 |
102 |
83 |
81 |
98 |
|
Co |
48 |
48 |
47 |
51 |
50 |
|
Ni |
49 |
56 |
48 |
51 |
59 |
|
Cu |
64 |
61 |
54 |
58 |
71 |
|
Zn |
79 |
93 |
71 |
77 |
125 |
|
As |
1.9 |
1.6 |
<1.50 |
<1.50 |
<1.70 |
|
Rb |
23 |
33 |
19 |
13 |
30 |
|
Sr |
153 |
139 |
157 |
146 |
140 |
|
Sb |
0.34 |
<0.180 |
0.22 |
<0.210 |
<0.210 |
|
Cs |
0.79 |
1.7 |
0.86 |
0.85 |
1.4 |
|
Ba |
139 |
193 |
142 |
136 |
146 |
|
Y |
30 |
25 |
29 |
30 |
31 |
|
La |
9.5 |
8.7 |
9.6 |
9.8 |
8.9 |
|
Ce |
19.9 |
19 |
20 |
21 |
18 |
|
Nd |
10 |
9.8 |
12 |
11 |
10 |
|
Sm |
2.99 |
2.84 |
2.99 |
3 |
2.8 |
|
Eu |
10 |
0.93 |
0.98 |
1 |
0.90, |
|
Tb |
0.69 |
0.64 |
0.7 |
0.76 |
0.74 |
|
Yb |
2.92 |
2.7 |
2.9 |
3.1 |
2.8 |
|
Lu |
0.44 |
0.38 |
0.41 |
0.47 |
0.44 |
|
Zr |
87 |
88 |
86 |
96 |
86 |
|
Hf |
2.22 |
2.1 |
2.2 |
2.3 |
2 |
|
Nb |
4.8 |
4.4 |
5.4 |
4.9 |
4.6 |
|
Ta |
0.38 |
0.35 |
0.45 |
0.45 |
0.34 |
|
Th |
2.2 |
1.9 |
2.2 |
2.3 |
1.9 |
|
U |
0.38 |
0.61 |
0.6 |
<0.60 |
0.28 |
|
Pd(ppb) |
1.4 |
1 |
1.5 |
1.5 |
1.5 |
|
Pt |
2 |
2 |
2.2 |
1.4 |
3.6 |
|
Au |
<12.0 |
<10.0 |
<5.0 |
<12.0 |
<10.0 |
|
|
|
|
|
|
|
| Table 2. Diabase dikes. | |||||
|
|
W-243404 |
W-243405 |
W-243417 |
W-243406 |
W-243407 |
|
|
FG-85 |
FG-85 |
FG-85 |
FG-85 |
FG-85 |
|
|
DV7 |
DV8 |
DV9 |
DV10 |
DVIL |
|
Lat. |
36°58'N |
36°37'N |
36°57'N |
36°57'N |
36°57'N |
|
Long. |
79° 9'W |
79° 9'W |
79° 9'W |
79° 9'W |
79°10'W |
|
SiO2 |
52.95 |
53.25 |
52.88 |
52.61 |
47.23 |
|
TiO2 |
1.03 |
1.04 |
1.09 |
1 |
0.47 |
|
A12O3 |
14.37 |
14.02 |
13.88 |
14.02 |
16.56 |
|
Fe2O3 |
13.45 |
13.35 |
13.44 |
13.27 |
12.7 |
|
Mno |
0.21 |
0.21 |
0.21 |
0.21 |
0.19 |
|
MgO |
5.58 |
5.97 |
5.82 |
6.21 |
9.68 |
|
CaO |
9.63 |
9.68 |
9.64 |
10.11 |
11.13 |
|
Na2O |
2.57 |
2.4 |
2.46 |
2.42 |
2.04 |
|
K2O |
0.69 |
0.64 |
0.62 |
0.3 |
0.22 |
|
P2O5 |
0.14 |
0.14 |
0.15 |
0.14 |
0.08 |
|
S |
0.06 |
0.08 |
0.07 |
0.07 |
0.07 |
|
F |
0.02 |
0.02 |
0.01 |
0.02 |
0.01 |
|
Cl |
<0.00 |
<0.00 |
0 |
<0.00 |
<0.00 |
|
Total |
100.71 |
100.8 |
100.28 |
100.38 |
100.38 |
|
B (ppm) |
- |
24.1 |
10.1 |
- |
32 |
|
Sc |
44 |
46 |
46 |
44 |
42 |
|
Cr |
74 |
79 |
72 |
81 |
310 |
|
Co |
47 |
48 |
47 |
46 |
58 |
|
Ni |
45 |
48 |
45 |
51 |
260 |
|
Cu |
63 |
64 |
62 |
67 |
126 |
|
Zn |
85 |
84 |
87 |
82 |
77 |
|
As |
1.7 |
<1.60 |
<2.70 |
<1.60 |
<1.50 |
|
Rb |
19 |
15 |
14 |
7 |
3 |
|
Sr |
153 |
151 |
143 |
191 |
77 |
|
Sb |
<0.210 |
<0.210 |
0.54 |
<0.220 |
<0.200 |
|
Cs |
1.1 |
1.1 |
0.67 |
<0.280 |
1.7 |
|
Ba |
157 |
148 |
144 |
152 |
109 |
|
Y |
37 |
28 |
30 |
24 |
20 |
|
La |
11 |
9.8 |
10 |
9.2 |
4 |
|
Ce |
21.4 |
21 |
21 |
19 |
8.5 |
|
Nd |
12 |
ll.0 |
13 |
11 |
<7.0 |
|
Sm |
3.3 |
3 |
3.2 |
2.97 |
1.29 |
|
EU |
1.07 |
1.02 |
1 |
0.92 |
0.47 |
|
Tb |
0.78 |
0.71 |
0.76 |
0.73 |
0.46 |
|
Yb |
3.3 |
3 |
3.2 |
2.9 |
2.7 |
|
Lu |
0.48 |
0.45 |
0.49 |
0.44 |
0.44 |
|
Zr |
89 |
89 |
94 |
92 |
43 |
|
Hf |
2.4 |
2.43 |
2.4 |
2 |
0.84 |
|
Nb |
5.2 |
5.7 |
5.3 |
5.3 |
1.5 |
|
Ta |
0.41 |
0.39 |
0.42 |
0.39 |
<0.160 |
|
Th |
2.2 |
2.3 |
2.4 |
1.9 |
0.33 |
|
U |
<l.60 |
0.55 |
0.67 |
0.74 |
<0.60 |
|
Pd(ppb) |
0.7 |
1.1 |
2 |
1.8 |
4.7 |
|
Pt |
1.8 |
2.4 |
3.2 |
1.5 |
3.1 |
|
Au |
<6.0 |
<9.0 |
<12.0 |
<10.0 |
<9.0 |
|
Table 3. Diabase dikes | |||||||
|
|
W-250879 |
W-250880 |
W-250881 |
W-250882 |
W-250883 |
W-250884 |
W-250885 |
|
|
C-15A-2 |
C-15B-2 |
C-15D-2 |
C-16A-1 |
C-47A-1 |
C-48C-2 |
C-78A-1 |
|
Lat. |
36°42'N |
36°38'N |
36°35'N |
36°40'N |
36°23'N |
36°52'N |
37°11'N |
|
Long. |
79°18'W |
79°26'W |
79°18'W |
79°33'W |
79°21'W |
79°38'W |
79°32'W |
|
Fe203* |
13.47 |
13.37 |
13.01 |
13.96 |
13.4 |
14.2 |
14.09 |
|
CaO |
8 |
8 |
8.3 |
9.5 |
8.8 |
8 |
9.1 |
|
Na2O |
3.09 |
2.97 |
3.13 |
2.8 |
3.22 |
3.15 |
2.75 |
|
Sc (ppm) |
42 |
39 |
40 |
44 |
41 |
43 |
44 |
|
Cr |
20 |
5.8 |
19 |
15 |
20 |
11 |
14 |
|
Co |
51 |
42 |
45 |
46 |
43 |
48 |
47 |
|
Ni |
15 |
7.3 |
15 |
16 |
15 |
12 |
13 |
|
Cu |
25 |
18 |
25 |
38 |
23 |
25 |
31 |
|
Zn |
110 |
120 |
110 |
120 |
110 |
140 |
128 |
|
As |
<2.30 |
<0.80 |
2.1 |
1.8 |
1.6 |
<0.90 |
1.9 |
|
Rb |
41 |
42 |
45 |
29 |
23 |
38 |
30 |
|
Sr |
300 |
280 |
320 |
290 |
310 |
290 |
310 |
|
Sb |
0.17 |
0.12 |
0.26 |
0.14 |
0.23 |
0.2 |
0.22 |
|
Cs |
0.61 |
0.78 |
0.52 |
1.1 |
0.96 |
0.78 |
0.74 |
|
Ba |
240 |
310 |
430 |
260 |
210 |
280 |
260 |
|
La |
15 |
18.6 |
15 |
15 |
15 |
15.8 |
14.5 |
|
Ce |
32 |
40 |
31 |
31 |
32 |
33 |
31 |
|
Nd |
16 |
19 |
16 |
16 |
15 |
19 |
16 |
|
Sm |
4.5 |
5.6 |
4.4 |
4.4 |
4.5 |
4.7 |
4.4 |
|
Eu |
1.4 |
1.6 |
1.4 |
1.3 |
1.4 |
1.42 |
1.34 |
|
Tb |
0.92 |
1.02 |
0.81 |
0.84 |
0.87 |
0.85 |
0.84 |
|
Yb |
3.5 |
3.9 |
3.2 |
3.4 |
3.3 |
3.4 |
3.4 |
|
Lu |
0.51 |
0.57 |
0.45 |
0.46 |
0.45 |
0.49 |
0.48 |
|
Rf |
3 |
3.8 |
3.1 |
3.2 |
3.1 |
3.2 |
2.98 |
|
Ta |
0.85 |
0.68 |
0.56 |
0.55 |
0.79 |
0.61 |
0.57 |
|
Th |
3 |
3.5 |
2.9 |
2.8 |
3.2 |
3.1 |
2.79 |
|
U |
0.74 |
0.93 |
0.92 |
0.73 |
0.86 |
0.82 |
0.7 |
|
Au (ppb) |
<2.80 |
<6.0 |
<2.50 |
<2.50 |
< 2.30 |
<4.0 |
<2.90 |