Spring Water Geochemistry: A Geothermal Exploration Tool in the Rhenohercynian Fold-and-Thrust Belt in Belgium

Spring water geochemistry is applied here to evaluate the geothermal potential in Rhenohercynian fold and thrust belt around deepest borehole Belgium (Havelange borehole: 5648 m MD). Fifty springs (few) wells Havelange were chosen according a multicriteria approach including hydrothermal source of “Chaudfontaine” (T ? 36 °C) taken as reference for area. The waters sampled, except Chaudfontaine present an in-situ T range 3.66–14.04 °C (mean 9.83 TDS (dry residue) salinity 46–498 mg/L. processing methods results are: hierarchical clustering, Piper Stiff diagrams, TIS, heat map, boxplots, geothermometry. Seven clusters are found allow us define three main types. first type, locally called “pouhon”, rich Fe Mn. second type contains interesting concentration indicators: Li, Sr, Rb. Moressée (?5 km East from borehole) belong this group. This last locality identified target further investigations. third group represents superficial with frequently high NO3 concentration. application conventional geothermometers context indicates very different reservoir temperatures. field applications these need be review geological conditions.