Fox Hills, Lower Hell Creek, Powder River Basin (15)
Comments on Geologic Parameters
15 Water Chemistry:
Fox Hills brine chemistry data, summarized by Henderson (1985), show that dissolved-solid concentrations increase downflow from initially low values in the northern recharge area. A plume of intermediate dissolved solids content is controlled by mixing of recharge waters with older, northwest-trending waters. Deep-basin Fox Hills waters are predominantly sodium bicarbonate, sulfate, and chloride.
15 Table:
| Well_name | Ca (mg/l) | Mg (mg/l) | Na (mg/l) | K (mg/l) | Cl (mg/l) | SO4 (mg/l) | HCO3 (mg/l) | CO3 (mg/l) |
|---|---|---|---|---|---|---|---|---|
| P7 | 54.0 | 42.0 | 24.0 | 13.0 | 5.4 | 56.0 | 386.0 | <1 |
| P6 | 29.0 | 16.0 | 140.0 | 14.0 | 2.4 | 66.0 | 483.0 | <1 |
| P3 | 1.4 | 0.1 | 330.0 | 1.4 | 23.0 | 150.0 | 626.0 | 12 |
| P2 | 1.9 | 0.4 | 300.0 | 1.3 | 18.0 | 150.0 | 583.0 | 8 |
| P20 | 18.0 | 1.2 | 390.0 | 3.8 | 3.5 | 384.0 | 557.0 | 20 |
| P30 | 100.0 | 67.0 | 170.0 | 6.0 | 9.0 | 610.0 | 391.0 | 0 |
| P41 | 100.0 | 54.0 | 130.0 | 7.0 | 12.0 | 490.0 | 389.0 | 0 |
| P9 | 1.7 | 0.1 | 360.0 | 2.0 | 21.0 | 97.0 | 790.0 | 13 |
| P17 | 2.7 | 0.4 | 370.0 | 4.0 | 30.0 | 1.6 | 982.0 | 2 |
| P15 | 29.0 | 9.0 | 600.0 | 3.3 | 9.0 | 650.0 | 912.0 | <1 |
| P10 | 93.0 | 45.0 | 490.0 | 5.8 | 1.1 | 1000.0 | 464.0 | <1 |
| P16 | 150.0 | 130.0 | 200.0 | 7.4 | 14.0 | 740.0 | 560.0 | <1 |
| P5 | 46.0 | 18.0 | 64.0 | 7.7 | 4.8 | 48.0 | 377.0 | <1 |
| P11 | 1.2 | 0.1 | 320.0 | 1.2 | 24.0 | 140.0 | 611.0 | 18 |
| P4 | 92.0 | 38.0 | 16.0 | 7.2 | 1.3 | 75.0 | 453.0 | <1 |
15 Reference:
Henderson, T., 1985, Geochemistry of ground-water in two sandstone aquifer systems in the northern Great Plains in parts of Montana and Wyoming: U. S. Geological Survey, Professional Paper 1402-C, p. C1-C84.
