|Fox Hills - Lower Hell Creek, Powder River Basin
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.
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.