Groundwater flow in a closed basin with a saline shallow lake in a volcanic area: Laguna Tuyajto, northern Chilean Altiplano of the Andes.

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.

[1]  J. A. Sánchez,et al.  Evolution from a freshwater to saline lake: a climatic or hydrogeological change? The case of Gallocanta Lake (northeast Spain) , 2007 .

[2]  S. L. Silva.  Geochronology and stratigraphy of the ignimbrites from the 21°30′S to 23°30′S portion of the Central Andes of northern Chile , 1989 .

[3]  M. Baker.  The nature and distribution of upper cenozoic ignimbrite centres in the Central Andes , 1981 .

[4]  S. Tweed,et al.  Arid zone groundwater recharge and salinisation processes; an example from the Lake Eyre Basin, Australia , 2011 .

[5]  W. Williams.  Environmental threats to salt lakes and the likely status of inland saline ecosystems in 2025 , 2002, Environmental Conservation.

[6]  C. Kohfahl,et al.  Characterising flow regime and interrelation between surface-water and ground-water in the Fuente de Piedra salt lake basin by means of stable isotopes, hydrogeochemical and hydraulic data , 2008 .

[7]  G. E. Stoertz,et al.  Geology of salars in Northern Chile , 1974 .

[8]  S. Kay,et al.  Regional chemical diversity, crustal and mantle sources and evolution of central Andean Puna plateau ignimbrites , 2010 .

[9]  E. Custodio,et al.  Using the Cl/Br ratio as a tracer to identify the origin of salinity in aquifers in Spain and Portugal , 2008 .

[10]  G. C. Lines.  Hydrology and surface morphology of the Bonneville Salt Flats and Pilot Valley playa, Utah , 1977 .

[11]  E. Custodio,et al.  Spatial average aquifer recharge through atmospheric chloride mass balance and its uncertainty in continental Spain , 2014 .

[12]  M. Vera.  Hidrogeología de zonas endorreicas en climas semiáridos: aplicación a los Monegros (Zaragoza y Huesca) , 1996 .

[13]  Emilio Custodio,et al.  Origin of waters from small springs located at the northern coast of Chile, in the vicinity of Antofagasta , 2014 .

[14]  E. Custodio.  Groundwater in volcanic hard rocks , 2007 .

[15]  Craig T. Simmons,et al.  On the evolution of salt lakes: Episodic convection beneath an evaporating salt lake , 2008 .

[16]  N. Ochmann,et al.  Study and Modelling of Saltwater Intrusion into Aquifers , 2012 .

[17]  H. Alonso,et al.  Geoquimica del Salar de Atacama, parte 1: origen de los componentes y balance salino , 1996 .

[18]  J. Pueyo,et al.  Solute inputs in the Salar de Atacama (N. Chile) , 2000 .

[19]  W. Giggenbach.  Isotopic shifts in waters from geothermal and volcanic systems along convergent plate boundaries and their origin , 1992 .

[20]  P. Francis,et al.  Volcanoes of the Central Andes , 1991 .

[21]  J. Puigdefabregas,et al.  Diffuse and concentrated recharge evaluation using physical and tracer techniques: results from a semiarid carbonate massif aquifer in southeastern Spain , 2011 .

[22]  Emilio Custodio Gimena,et al.  Hipótesis sobre el origen de la salinidad de las aguas subterráneas en la isla de Fuerteventura, Archipiélago de Canarias , 2003 .

[23]  C. Castañeda,et al.  Water balance in the playa-lakes of an arid environment, Monegros, NE Spain , 2008 .

[24]  E. Custodio,et al.  Atmospheric chloride deposition in continental Spain , 2008 .

[25]  Rayco Marrero Díaz.  Modelo hidrogeoquímico del acuífero de las cañadas del Teide, Tenerife, Islas Canarias , 2010 .

[26]  J. Warren.  Evaporites: Their Evolution and Economics , 1999 .

[27]  E. Custodio,et al.  Groundwater flow in a relatively old oceanic volcanic island: the Betancuria area, Fuerteventura Island, Canary Islands, Spain. , 2014, The Science of the total environment.

[28]  François Risacher,et al.  Geoquímica de aguas en cuencas cerradas: I, II y III regiones - Chile , 1999 .

[29]  J. Jankowski,et al.  Solute budget for an arid‐zone groundwater system, Lake Amadeus, central Australia , 1991 .

[30]  R. Aravena,et al.  Isotopic composition and origin of the precipitation in Northern Chile , 1999 .

[32]  W. Giggenbach.  The isotopic composition of waters from the El Tatio geothermal field, Northern Chile , 1978 .

[33]  J. Benavente,et al.  Estimation of ground-water exchange with semi-arid playa lakes (Antequera region, southern Spain) , 2006 .

[34]  Emilio Custodio Gimena,et al.  Utilización de la relación Cl-Br como trazador hidroquímico en hidrología subterránea , 2000 .

[35]  Precipitations d'altitude, eaux souterraines et changements climatiques de l'altiplano nord-chilien , 1998 .

[36]  C. Ammann,et al.  Late Quaternary Glacier response to humidity changes in the arid Andes of Chile (18–29°S) , 2001 .

[37]  W. Giggenbach.  Geothermal solute equilibria. Derivation of Na-K-Mg-Ca geoindicators , 1988 .

[38]  S. Job.  Accessory respiration in the climbing perch anabas scandens , 1976, Hydrobiologia.

[39]  E. Vareschi,et al.  Aquatic biodiversity and saline lakes: Lake Bogoria National Reserve, Kenya , 2003, Hydrobiologia.

[40]  E. Custodio.  Estimation of aquifer recharge by means of atmospheric chloride deposition balance in the soil , 2010 .

[41]  R. Trumbull,et al.  La Pacana caldera, N. Chile: a re-evaluation of the stratigraphy and volcanology of one of the world's largest resurgent calderas , 2001 .

[42]  L. J. Lambán,et al.  Isotopic and hydrogeochemical characterization of high-altitude karst aquifers in complex geological settings. The Ordesa and Monte Perdido National Park (Northern Spain) case study. , 2015, The Science of the total environment.

[43]  W. W. Wood,et al.  Hydrogeologic processes in saline systems: playas, sabkhas, and saline lakes , 2002 .

[44]  P. Francis,et al.  Sources of two large ignimbrites in the central andes: Some landsat evidence , 1978 .

[45]  F. Risacher,et al.  The origin of brines and salts in Chilean salars: a hydrochemical review , 2003 .

[46]  J. Yáñez,et al.  Evaporation from shallow groundwater in closed basins in the Chilean Altiplano , 2010 .

[47]  F. Comín,et al.  Spanish salt lakes: Their chemistry and biota , 2004, Hydrobiologia.

[48]  M. Barbieri,et al.  New chemical and original isotopic data on waters from El Tatio geothermal field, northern Chile , 2005 .

[49]  C. Duffy,et al.  Groundwater circulation in a closed desert basin: Topographic scaling and climatic forcing , 1988 .

[50]  A. Sáez,et al.  Relación de aguas superficiales y subterráneas en el área del lago Chungará y lagunas de Cotacotani, norte de Chile: un estudio isotópico , 2006 .

[51]  S. Self,et al.  Enigmatic clastogenic rhyolitic volcanism: the Corral de Coquena spatter ring, North Chile , 2008 .

[52]  C. Duffy,et al.  Density-driven groundwater flow in closed desert basins: field investigations and numerical experiments , 1997 .

[53]  D. Haukos,et al.  The importance of playa wetlands to biodiversity of the Southern High Plains , 1994 .

[54]  Dga. Dirección General De Aguas.  Balance hídrico de Chile , 2015 .

[55]  M. A. García-Vera,et al.  Inverse modeling of groundwater flow in the semiarid evaporitic closed basin of Los Monegros, Spain , 1998 .

[56]  A. Navas,et al.  Responses of a Saline Lake Ecosystem in a Semiarid Region to Irrigation and Climate Variability , 2000 .

[57]  U. Hammer,et al.  Saline lake ecosystems of the world , 1986 .

[58]  A. Bedmar.  Composición isotópica de las precipitaciones y aguas subterráneas de la península Ibérica , 1994 .

[59]  I. Clark,et al.  Environmental Isotopes in Hydrogeology , 1997 .

[60]  F. Risacher,et al.  Origin of Salts and Brine Evolution of Bolivian and Chilean Salars , 2009 .