Evaluation of Geothermal Resources in the Chaves Region (North Portugal)

Abstract

Geological, geochemical and geophysical surveys were performed in the Chaves area to built up the hydrothermal model associated with the Chaves hot springs. The geomorphology of the survey area is dominated by the Chaves Depression, which is a graben whose axis is oriented NNE-SSW. Two major geological structural features have been considered in the area: the so called Chaves fault and the faulted system, crossing the above mentioned Depression close to and Chaves town. The integrated interpretation of the geological, geochemical and geophysical data, suggests a meteoric origin for Chaves thermal waters which infiltrate in the northeast zone of the Chaves Depression or farther areas, percolate at great depth and ascend at Chaves Depression, probably due to the cross line zones of the existing fault systems. In fact, in the above mentioned zones, low resistivity values were measured, which are probably associated with the hydrothermal circulation.