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Fault-Related Thermal Springs: Water Origin and Hydrogeochemical Processes at Liquiñe Area (Southern Volcanic Zone, Chile)
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  • Linda Daniele,
  • Matías Taucare,
  • Tomas Roquer,
  • Benoît Viguier,
  • Josefa Sepúlveda,
  • Eduardo Molina,
  • Gloria Arancibia,
  • Diego Aravena,
  • Mauricio Muñoz,
  • Jorge G. F. Crempien,
  • Antonio Delgado-Huertas,
  • Diego Morata
Linda Daniele
Universidad de Chile, Universidad de Chile
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Matías Taucare
Universidad de Chile, Universidad de Chile

Corresponding Author:[email protected]

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Tomas Roquer
Pontificia Universidad Católica de Chile, Pontificia Universidad Católica de Chile
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Benoît Viguier
Universidad de Chile, Universidad de Chile
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Josefa Sepúlveda
Pontificia Universidad Católica de Chile, Pontificia Universidad Católica de Chile
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Eduardo Molina
Pontificia Universidad Católica de Chile, Pontificia Universidad Católica de Chile
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Gloria Arancibia
Universidad Catolica de Chile, Universidad Catolica de Chile
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Diego Aravena
Andean Geothermal Center of Excellence (CEGA), Andean Geothermal Center of Excellence (CEGA)
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Mauricio Muñoz
Andean Geothermal Center of Excellence (CEGA), Andean Geothermal Center of Excellence (CEGA)
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Jorge G. F. Crempien
Pontificia Universidad Católica de Chile, Pontificia Universidad Católica de Chile
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Antonio Delgado-Huertas
Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR), Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR)
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Diego Morata
Universidad de Chile, Universidad de Chile
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Abstract

Geothermal activity in the Chilean Southern Volcanic Zone is strongly controlled by the regional Liquiñe-Ofqui Fault System (LOFS) and the Andean Transverse Faults (ATF). We analyzed fifteen thermal springs in the Liquiñe area to assess the origin and the main physicochemical processes related to the LOFS and ATF.
Major, minor and trace elements identify two defined clusters spatially related to the regional fault systems. In both clusters, ionic relationships suggest that the principal hydrogeochemical processes are mainly dominated by water-rock interactions. Factorial analysis provided two factors: i) F1 (65.1%), saturated by Cl, HCO, Na, SiO, Li, B and Cs, represents water-rock interaction processes driven by temperature in presence of CO; ii) F2 (28.5%) represented by SO and Mo, represents a minor water-rock interaction enhanced by the presence of HS. Samples associated to the LOFS have high scores of both factors, while those from the ATF have only high factor 1 scores. Ionic ratios compared with literature data, clearly identify the samples spatially associated to the LOFS from the ones associated to the ATF with a fuzzy pattern.
Water stable isotopes values suggest a meteoric origin with small deviations from local meteoric isotopic line. CO exchange with slightly high and low temperature water rocks interaction is present in most of the samples.
Our results indicate that groundwater circulation along faults is a complex process where different constraints influence the final hydeogeochemistry and reaction intensity. Finally, the established processes at Liquiñe area are not upscalable at the whole Southern Volcanic Zone.