El Tatio geothermal field

El Tatio is situated in the Altiplano–Puna Volcanic Complex. Surface thermal manifestations (fumaroles, hot springs, sinter cones, perpetual spouters, mud volcanoes and sinter terraces) are located on the upper levels in a Pliocene graben ~4 km wide and 6 km long. The western flank of the graben is the Serranía de Tucle–Loma Lucero horst, and the eastern flank is an alignment of andesitic stratovolcanoes and rhyolitic domes that form the summit of the Andes mountains at this latitude (Fernández-Turiel et al., 2005). The geothermal field is contained in ignimbrites and lavas of the upper Cenozoic that overlies a basement of Mesozoic sedimentary rocks (Glenon and Paff, 2003).

According to geochemical and structural data, the water comes from precipitation in an area located at 12–20 km to the E–SE of El Tatio, and it is heated by volcanic complexes (Pastos Grandes and Cerro Guacha caldera systems) located east of the field (Glenon and Paff, 2003). Hydrothermal manifestations occur over a 30 km2 area, divided into three basins, with most hydrothermal activity concentrated in the Upper Basin of 10 km2. The hot water is mainly confined to two aquifers, which are overlain by volcanic formations (Tucle tuffs and Tatio ignimbrite). The El Tatio episodic hot springs eruptions have a maximum discharge that ranges between 250 to 500 lts/second, depending on seasonal changes; with a mean erupting column height of two meters and a maximum heigth of 8 meters. (Glenon and Paff, 2003; Fernández-Turiel et al., 2005).