Hydrochemical environments of carbonate terrains

Waters within a carbonate aquifer have often been classified on a hydrologie basis. The significance of such grouping to the understanding of the geochemical processes acting in the aquifer is dependent on the classes having a distinctive chemistry. One hundred sixty‐six reliable chemical analyses of carbonate waters from Pennsylvania were grouped on a hydrologic basis, and the groupings were tested by a stepwise linear discriminant function analysis. Two parameters (degree of calcite saturation and equilibrium carbon dioxide partial pressure) are sufficient to distinguish the groups at the 0.005 confidence level and provide a reliable way to examine the geochemical evolution of the waters in the carbonate drainage basin.