Seven (7) samples of diabase from five (5) dikes were collected by two (2) workers in Virginia and analyzed by the U.S. Geological Survey. aura Cummins of Florida State University contributed four (4) samples from four (4) dikes in the Piedmont for which selected major- and traceelement chemistry is here provided; the balance of the chemistry (majorand selected trace-element data) is docu~ehted in Cummins (1987). Froelich and Gottfried collected three (3) samples across a single dike in the Farmville basin for which complete chemistry is documented here. The platinum (Pt) and palladium (Pd) abundances are very low, consistent with those of the high Fe, quartz-normative (HFQ) magmas throughout the province.
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diabase dikes of Virginia: unpublished Ph.D. thesis, Florida State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.
| FARMVILLE AND SCOTTSVILLE BASINS AND VICINITY, VIRGINIA | ||
| SAMPLE NO. | MAGMA TYPE | DESCRIPTION OF SAMPLES |
| FG VF-1 | High Fe, quartz normative | Diabase dikes - Table 1 Diabase |
| -2 | ||
| -3 | ||
| C-131A-1 | High Fe, quartz normative | Diabase dikes L. Cummins samples Table 1 Diabase |
| C-154A-1 | ||
| C-154D-1 | ||
| C-154D-3 | ||
| Table 1. Farmville and Scottsville basins and vicinity, Virginia. Diabase dikes. | |||||||
| W-243895 | W-243896 | W-243897 | W-250886 | W-250887 | W-250888 | W-250889 | |
| FG-VF-I | FG-VF-2 | FG-VF-3 | C-131A-1 | C-154A-1 | C-154D-1 | C-154D-3 | |
| Lat. | 37°24'N | 37°24'N | 37°24'N | 37°38'N | 37°53'N | 37°47'N | 37°51'N |
| Long. | 78°24'W | 78°24'W | 78°24'W | 78°31'W | 78°36'W | 78°35'W | 78°36'W |
| SiO2 | 52.7.0 | 52.6 | 52.6 | ||||
| TiO2 | 1.13 | 1.08 | 1.1 | ||||
| A12O3 | 13.7 | 13.8 | 13.7 | - | - | - | - |
| Fe2O3* | - | - | - | 14.59 | 14.44 | 14.59 | 14.3 |
| Fe2O3 | 2.85 | 2.87 | 2.23 | - | - | - | - |
| FeO | 10.2 | 10.8 | 10.8 | - | |||
| MnO | 0.22 | 0.22 | 0.22 | - | |||
| MgO | 5.44 | 5.63 | 5.5 | - | ---- | - | - |
| CaO | 9.3 | 10.2 | 10.2 | 9.7 | 9.9 | 9.4 | 10.2 |
| Na2O | 2.57 | 2.41 | 2.33 | 2.45 | 2.48 | 2.47 | 2.52 |
| K2O | 0.78 | 0.53 | 0.56 | - | - | - | - |
| P2O5 | 0.15 | 0.14 | 0.14 | - | - | - | - |
| H20+ | 0.9 | 0.72 | 0.63 | - | - | - | - |
| H2O- | 0.2 | 0.09 | 0.08 | - | - | - | - |
| CO2 | <0.01 | 0.03 | 0.02 | - | - | - | - |
| S | 0.1 | 0.09 | 0.1 | ||||
| F | 0.03 | 0.01 | 0.03 | ||||
| Cl | <0.00 | <0.00 | <0.00 | ||||
| Total | 100.28 | 101.23 | 100.24 | ||||
| B (ppm) | 13 | 7.3 | 7.1 | ||||
| Sc | 47 | 50 | 47 | 49 | 49 | 48 | so |
| Cr | 23 | 25 | 23 | 18 | 20 | 19 | 19 |
| Co | 49 | 50 | 47 | 49 | 52 | 50 | 52 |
| Ni | 35 | 28 | 33 | 17 | 18 | 18 | 18 |
| Cu | 67 | 60 | 68 | 58 | 50 | 63 | 46 |
| Zn | 98 | 75 | 83 | 120 | 120 | 130 | 110 |
| Ga | 23 | 22 | 22 | - | - | - | - |
| As | <2.60 | <2.30 | <2.40 | 2.2 | 1.9 | 2.4 | <1.00 |
| Rb | 29 | 24 | 19 | 27 | 29 | 32 | 30 |
| Sr | 226 | 153 | 152 | 250 | 160 | 240 | 180 |
| Ag | 0.023 | 0.025 | 0.027 | - | - | - | - |
| Sb | 0.32 | <0.30 | <0.40 | 0.15 | 0.18 | <0.210 | 0.21 |
| Cs | 0.58 | 0.74 | 0.61 | 1.6 | 1.2 | 1.1 | 1 |
| Ba | 240 | 137 | 157 | 220 | 150 | 220 | ISO |
| y | 29 | 28 | 29 | - | - | - | - |
| La | 10.3 | 9.8 | 9.7 | 12 | 12 | 12 | 10 |
| Ce | 21 | 20 | 19 | 23 | 24 | 24 | 21 |
| Nd | 12 | 11 | 11 | 13 | 13 | 12 | 13 |
| Sm | 3.4 | 3.3 | 3.3 | 3.7 | 3.6 | 3.5 | 3.3 |
| Eu | 1.1 | 1.05 | 1 | 1.17 | 1.1 | 1.12 | 1.1 |
| Tb | 0.76 | 0.73 | 0.72 | 0.82 | 0.8 | 0.82 | 0.74 |
| Yb | 3.3 | 3.7 | 3.4 | 3.4 | 3.5 | 3.2 | 3.2 |
| Lu | 0.51 | 0.49 | 0.53 | 0.49 | 0.5 | 0.46 | 0.47 |
| Zr | 101 | 96 | 98 | - | - | - | - |
| Hf | 2.3 | 2.2 | 2.3 | 2.7 | 2.8 | 2.7 | 2 |
| Nb | 4.6 | 4.6 | 5.2 | - | - | - | - |
| Ta | 0.35 | 0.35 | 0.36 | 0.61 | 1.1 | 0.95 | 0.52 |
| Th | 2.5 | 2.2 | 2.3 | 3 | 2.9 | 2.8 | 2.1 |
| u | 0.69 | 0.6 | 0.57 | 0.86 | 0.91 | 0.73 | 0.52 |
| Pd(ppb) | 1.5 | 1.3 | 2.5 | - | - | - | - |
| Pt | 1.9 | 3.2 | 5.7 | - | - | - | - |
| Au | <7.0 | <9.0 | 220 | <3.0 | <2.50 | <2.30 | <1.90 |