Fecha: 7 agosto 2026
Autor Ckelar: Philippe Robidoux
Otros autores: Marco Taussi, Fausto Grassa, Alberto Renzulli, Pierangelo Romano, Maximiliano Seguel, Germain Rivera, Santiago Maza, Manfredi Longo, Diego Morata y Gianni Volpi.
Revista científica: Journal of Volcanology and Geothermal Research
Abstract
The Cerro Pabellón geothermal power plant, located adjacent to the Cerro Pabellón Dome (CPD) and the Apacheta–Aguilucho Volcanic Complex AAVC (northern Chile), exploits a high-temperature geothermal system whose connection to regional magmatism and structural controls remains uncertain. This novel monitoring approach and industrial protocol aims to determine whether the Cerro Pabellón reservoir is an isolated system or if it is connected to deeper magmatic and hydrothermal sources within the Pabelloncito Graben. To address this question, the study combines two complementary approaches: (1) Advanced geothermal plant monitoring, integrating fumarolic and production steam geochemistry, gas geothermometry, and noble gas isotope analyses, (2) Updated field and laboratory igneous petrology techniques, including mineral-separate fluid inclusion studies and geothermobarometry datasets. Together, these methods are used within a structural and spatial framework to constrain both regional and local fluid pathways and heat sources at Cerro Pabellón. The results indicate that the reservoir is not a closed blind system. The Apacheta–Aguilucho Volcanic Complex hosts a lateral discharge vent hydraulically connected to a deep graben geothermal cell while maintaining a CO2-rich gas source. Isotopic noble gas chemistry confirms a compositional continuum with regional volcanic monitoring, characterized by low 3He/4He values (Rc ≈ 2.1 Ra). N2/He and He/Ar ratios define fault-controlled groups within the Pabelloncito Graben, indicating structural controls on contamination and fluid sources. Exploration wells located >500 m from major faults exhibit lower air/water contamination and compositions closer to the regional end-member (Rc/Ra = 1.7–2.1). Mineral geothermobarometry and gas geochemistry indicate magma apophyses at depths <3.5 km. Mineral-separate noble gas signatures show CPD values <1.0 Ra and primitive Poruña mafic scoria cone values of 4.0–7.0 Ra, recording a regional mantle source of 6.4–7.9 Ra modified by degassing and polybaric fluid entrapment. Geothermobarometry (0.8–2.0 kb) indicates persistent Pleistocene-to-present magmatic heating, with deeper sources extending to >6.0 kb near the inferred Altiplano–Puna Magma Body (APMB) roof. These findings refine the geothermal model and improve exploration strategies by constraining spatio-temporal fluid transport.