Structural control on hydrothermal upwelling in the Ixtlán de los Hervores geothermal area, Mexico

Hot springs and related deposits are common features in active geothermal areas around the world. In this study, centered on the Ixtlan de los Hervores geothermal zone (Michoacan, Mexico), we analyzed the distribution of active hydrothermal manifestations and hot-spring deposits as well as the local stratigraphy to determine the influence of the faults in the hydrothermal fluid circulation. The hydrothermal manifestations are mainly represented by hot springs with water temperatures up to 92 °C (depositing silica sinter at the surface). All the hydrothermal features are located within a tectonic depression controlled by the potentially active Ixtlan-Encinal fault. Inside this depression, lacustrine sediments were deposited from Pliocene up to the Hispanic colony period (~XVI–XIX centuries). A pre-Hispanic silica-sinter layer was identified beneath the lacustrine sediments, as well as a debris flow deposit, rich in pottery, suggesting that the debris flow may have affected local inhabitants during pre-Hispanic times.