RARE EARTH ELEMENT FRACTIONATION AS AN INDICATOR OF SPRING WATER SOURCE

Few techniques exist for determining the sustainability of water flow from a karst spring. For ten springs in karst areas of Pennsylvania and West Virginia, rare earth element (REE) fractionation was evaluated as an indicator of sustainability and surface influence. We hypothesized that springs with a greater component of surface flow, and therefore more variable and less sustainable discharge, would have larger negative Ce anomalies due to the greater presence of oxygen in the aquifer. Three sets of springs were included. Warm and Cold springs were studied in Huntingdon, PA, six different springs were studied in the Great Valley near Martinsburg, WV, and two springs were studied in the Berkeley Springs, WV area. Water samples taken at each of the springs were analyzed using ion chromatography, ICP-MS and ICP-OES. The highest concentration of total REE was found in the cold, sandstone spring. The lowest concentrations of REEs were found in the two warm springs. All cold water springs had negative Ce anomalies but this was less pronounced or non-existent in the warm springs. In the Great Valley springs, a negative Eu anomaly was more pronounced in the variable headwater springs than in the downstream springs that are more consistent thermally and/or likely to be fed by a deeper-water source.