The effect of soil activity on the chemistry of carbonate groundwaters

Regional variations in HCO 3 − concentrations of carbonate groundwaters are explained by the combination of a simple ecological model of soil CO 2 production and a consideration of the manner in which soil water, soil air, and carbonate materials interact. Carbonate groundwaters in North America are divided into those which have evolved largely under open system conditions and those which have evolved under closed system conditions. The open system group members (with one exception) all come from high latitudes, and it is suggested that recurrent glaciations have acted to replenish soil zone carbonate materials and maintain the soil zone as an important source of dissolved carbonate minerals.