Publication Date:
2022-02-11
Description:
The Tolhuaca hydrothermal system is one of the few attested geothermal resources in Chile. While
recent investigations provided some insights into the depth and temperature of the geothermal reservoirs
and the chemical and mineralogical evolution of the hydrothermal system, little is still known about the
CO2 degassing of the system and the local and shallow control of fluid pathways. Here, we document
the soil CO2 degassing and soil temperature distributions in the southern part of the Tolhuaca
hydrothermal system and at one of its northern fumaroles, and provide a first estimate of its total CO2
release. The surveyed area is responsible for a total CO2 emission of up to 30 t d-1. Hydrothermal CO2
emissions (~ 4-27 t d-1) are mostly restricted to the thermal manifestations or generally distributed along
NNW trending lineaments, sharing the same orientation as the volcanic vents and thermal springs and
fumaroles. Hydrothermal CO2 fluxes, fumaroles and thermal springs are generally encountered in
topographic lows, in close vicinity of streams and often in clay-rich pyroclastic units, highlighting a
relation between landscape evolution and the activity of the hydrothermal system. We suggest that
glacial unloading and incision of the stream inside the clay-rich units have likely enhanced locally the
permeability, creating a preferential pathway for the migration of deeper fluid to the surface. As several
hydrothermal systems in the Andes are found on the flank of volcanoes hosting glaciers, we propose
that they could have had a similar development to that of the Tolhuaca hydrothermal system.
Description:
Published
Description:
107316
Description:
4V. Processi pre-eruttivi
Description:
JCR Journal
Keywords:
CO2 emission
;
Tolhuaca volcano
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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