Trabajo presentado en el 8th International Symposium on Andean Geodynamics (ISAG), realizado en Quito-Ecuador, del 24-26 setiembre, 2019. Evento organizado por el Instituto Geofísico, Escuela Politécnica Nacional (IG-EPN) del Ecuador, y el French Institut de Recherche pour le Développement (IRD).

Thermal waters and vapor discharges (hot springs, geysers, solfataras, and fumaroles) are common phenomena in volcanic regions at active plate boundaries, and the Central Andes are no exception. The Colca River basin in S Peru is a highly diversified and complex thermal region with unresolved questions on the origin of thermal fluids, reservoir temperature, and connections with tectonic and/or volcanic activity. To answer these, we used hydrogeochemical analysis of 35 water samples from springs and geysers, together with isotopic (δ18O and δD) analysis, chemical and mineral studies of precipitates collected in the field around these outflows, and field observations. We aimed (1) to recognize the geochemistry of thermal waters and precipitates in the central part of the Colca River basin, (2) to identify fluid sources and their origin, (3) to estimate the temperature of a potential geot...