title: Groundwater flow in a closed basin with a saline shallow lake in a volcanic area: Laguna Tuyajto, northern Chilean Altiplano of the Andes.
abstract: Laguna Tuyajto is a small, shallow saline water lake in the Andean Altiplano of northern Chile. In the eastern side it is fed by springs that discharge groundwater of the nearby volcanic aquifers. The area is arid: rainfall does not exceed 200mm/year in the rainiest parts. The stable isotopic content of spring water shows that the recharge is originated mainly from winter rain, snow melt, and to a lesser extent from some short and intense sporadic rainfall events. Most of the spring water outflowing in the northern side of Laguna Tuyajto is recharged in the Tuyajto volcano. Most of the spring water in the eastern side and groundwater are recharged at higher elevations, in the rims of the nearby endorheic basins of Pampa Colorada and Pampa Las Tecas to the East. The presence of tritium in some deep wells in Pampa Colorada and Pampa Las Tecas indicates recent recharge. Gas emission in recent volcanoes increase the sulfate content of atmospheric deposition and this is reflected in local groundwater. The chemical composition and concentration of spring waters are the result of meteoric water evapo-concentration, water-rock interaction, and mainly the dissolution of old and buried evaporitic deposits. Groundwater flow is mostly shallow due to a low permeability ignimbrite layer of regional extent, which also hinders brine spreading below and around the lake. High deep temperatures near the recent Tuyajto volcano explain the high dissolved silica contents and the δ(18)O shift to heavier values found in some of the spring waters. Laguna Tuyajto is a terminal lake where salts cumulate, mostly halite, but some brine transfer to the Salar de Aguas Calientes-3 cannot be excluded. The hydrogeological behavior of Laguna Tuyajto constitutes a model to understand the functioning of many other similar basins in other areas in the Andean Altiplano.
authors.affiliation: Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta, Chile; Centro de Investigación Tecnológica del Agua en el Desierto (CEITSAZA), Universidad Católica del Norte, Casilla 1280, Antofagasta, Chile. Electronic address: cherrera@ucn.cl.
authors.forename: Christian
authors.initials: C
authors.lastname: Herrera
authors.affiliation: Department of Geo-Engineering, Technical University of Catalonia/Barcelona Tech (UPC), Barcelona, Spain.
authors.forename: Emilio
authors.initials: E
authors.lastname: Custodio
authors.affiliation: Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta, Chile.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Chong
authors.affiliation: Geological Institute of Spain (IGME), Zaragoza, Spain.
authors.forename: Luis Javier
authors.initials: LJ
authors.lastname: Lambán
authors.affiliation: Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta, Chile.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Riquelme
authors.affiliation: Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta, Chile.
authors.forename: Hans
authors.initials: H
authors.lastname: Wilke
authors.affiliation: Department of Geo-Engineering, Technical University of Catalonia/Barcelona Tech (UPC), Barcelona, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Jódar
authors.affiliation: Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta, Chile; Centro de Investigación Tecnológica del Agua en el Desierto (CEITSAZA), Universidad Católica del Norte, Casilla 1280, Antofagasta, Chile.
authors.forename: Javier
authors.initials: J
authors.lastname: Urrutia
authors.affiliation: Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta, Chile; Centro de Investigación Tecnológica del Agua en el Desierto (CEITSAZA), Universidad Católica del Norte, Casilla 1280, Antofagasta, Chile.
authors.forename: Harry
authors.initials: H
authors.lastname: Urqueta
authors.affiliation: Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta, Chile.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Sarmiento
authors.affiliation: Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta, Chile; Centro de Investigación Tecnológica del Agua en el Desierto (CEITSAZA), Universidad Católica del Norte, Casilla 1280, Antofagasta, Chile.
authors.forename: Carolina
authors.initials: C
authors.lastname: Gamboa
authors.affiliation: Centro de Investigación y Desarrollo en Recursos Hídricos (CIDERH), Vivar 493, Iquique, Chile.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Lictevout
keywords: Andean Altiplano Chile; Arid area; Groundwater flow; Laguna Tuyajto; Stable water isotopes; Volcanic formations