Deciphering origins and pathways of low-enthalpy geothermal waters in the unconventional geothermal system of Juchipila graben (Central Mexico)
Por:
Billarent-Cedillo, Andrea, Levresse, Gilles, Ferrari, Luca, Inguaggiato, Claudio, Inguaggiato, Salvatore, Hernandez-Perez, Eliseo, Hernandez-Espriu, Antonio, Corbo Camargo, Fernando, Carrera Hernandez, Jaime, Arias-Paz, Alberto
Publicada:
1 jul 2021
Resumen:
This work presents hydrochemical results for groundwater and dissolved
gas samples collected from a thermal and cold aquifer in the Juchipila
Basin, in southern Sierra Madre Occidental, central Mexico. Thermal
springs in the Juchipila Basin reach temperatures of 60 degrees C, these
manifestations are not related to recent or active volcanism as are all
the known geothermal fields in Mexico. The thermal waters (>32 degrees
C) are Na-HCO3 and Na-SO4 type, with an anomalous concentration of F, B,
Li, and As. Their chemistry likely results from water-rock interaction
processes. The cold waters (<32 degrees C) have a Ca-HCO3 composition
typical of recent infiltration and shallow flow, but they have an
anomalous concentration of NO3. The delta H-2 and delta O-18 indicate a
common meteoric source for the warm and cold water plotting along an
evaporation line. The waters have higher CO2 and He concentrations than
the air-saturated water. The helium composition is mainly atmospheric
and terrigenous with a mantle helium contribution of up to 14%. This
suggests that faults affecting the region are deeply rooted, permitting
mantle helium uprise. Geothermometry gives mean reservoir temperatures
of 58-102 degrees C. Based on these results, we propose a model of
hydrothermal circulation in the Juchipila Basin, in which rainwater
infiltrates deeply through the graben edges fault system, dissolves ions
and crustal helium, incorporates mantle helium, while heated by the
geothermal gradient, and eventually surges and mixes with the cold,
shallow aquifer along faults cutting the whole succession within the
graben.
Filiaciones:
Posgrado en Ciencias de la Tierra, UNAM Campus Juriquilla Blvd. Juriquilla 3001, Querétaro, 76230, Mexico
Centro de Geociencias, UNAM Campus Juriquilla Blvd. Juriquilla 3001, Querétaro, 76230, Mexico
Departamento de Geología, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Carretera Ensenada-Tijuana 3918, Ensenada, Baja California, Mexico
Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Bologna, Via Donato Creti 12, Bologna, Italy
Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palermo, via Ugo La Malfa, 143, Palermo, 90145, Italy
Hydrogeology Group, Facultad de Ingeniería, UNAM, Circuito Escolar 04360, Ciudad de Mexico, CDMX, C.U., 04510, Mexico
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