A geochemical approach for the evaluation of the geothermal potential of Yemen

Thermal springs, fumaroles and boiling water pools from continental Yemen have been investigated for chemical and isotopic compositions. Whatever the emergence, all the water discharges have an isotopic signature of meteoric origin. Springs seeping out from high altitudes in the central volcanic plateau show a prevalent Na-HCO3-composition, clearly affected by an anomalous flux of CO2 deriving from the active hydrothermal systems located in the Jurassic Amran Group limestone sequence, likely underlying the 2000-3000 m thick volcanic suite and/or the Cretaceous Tawilah Group sandstone. All the CO2-rich gas samples have a ?13C-CO2 signature that falls in the range of mantle CO2 (-3