| Title | The Nevados de Chillán as a fault-controlled Geothermal System in Southern Chile: a review of the last achievements to a new conceptual model |
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| Authors | Arancibia G, Mura V, Oyarzo-Céspedes I, López-Contreras C, Merchán F, Pineda C, Browning J, Morata |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | Nevados de Chillán Geothermal System (NChGS) is located on the SW border of the active Nevados de Chillán Volcanic Complex, belonging to the Southern Andes Volcanic Zone in the Chilean Andean Cordillera. NChGS was initially explored at the end of the ‘90s by the French Geothermal National Company, and a continuous 1000.85 m depth exploration well (Nieblas-1) was drilled in 2009 by the Chilean National Geothermal Company. During the last five years, our research group has focused the studies of this active geothermal system from a multidisciplinary approach. Combining mineralogical, geochemical, structural, and geophysical methods, and numerical modeling, we have developed an updated conceptual model for the NChGS. A high-enthalpy reservoir is hosted in intensely fractured Miocene granitic rocks, where temperatures could reach up to 250° C at 1200–1300 m depths. In contrast, a clay cap of ~600 m thick is developed in volcanic overlying sequences, and surface thermal manifestations (fumaroles, thermal and mud springs, etc.) are strongly fault-controlled. Our numerical models suggest hydrothermal fluid residence times of a thousand years are required to reach a steady-state thermal configuration. Finally, we have estimated a geothermal potential (volumetric method) of 39 ± 1 MWe. Although today, NChGS is an abandoned project, the electricity demand for the Nevados de Chillán ski resort and the surrounding touristic Las Trancas Valley, coupled with a more diverse direct use rather than limited thermal spas, could be an economic incentive for a sustainable development of this geothermal system. Acknowledgments: ANID-FONDECYT Project 1220729 funded this work. |