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| Titel |
Surface geothermal exploration in the Canary Islands by means of soil CO2 degassing surveys |
| VerfasserIn |
Marta García-Merino, Fátima Rodriguez, Eleazar Padrón, Gladys Melián, María Asensio-Ramos, José Barrancos, Pedro A. Hernández, Nemesio M. Pérez |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250143721
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| Publikation (Nr.) |
 EGU/EGU2017-7471.pdf |
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| Zusammenfassung |
| With the exception of the Teide fumaroles, there is not any evidence of hydrothermal fluid
discharges in the surficial environment of the Canary Islands, the only Spanish territory with
potential high enthalpy geothermal resources. Here we show the results of several diffuse
CO2 degassing surveys carried out at five mining licenses in Tenerife and Gran Canaria with
the aim of sorting the possible geothermal potential of these five mining licenses. The
primary objective of the study was to reduce the uncertainty inherent to the selection of the
areas with highest geothermal potential for future exploration works. The yardstick used to
classify the different areas was the contribution of volcano-hydrothermal CO2 in the diffuse
CO2 degassing at each study area. Several hundreds of measurements of diffuse CO2
emission, soil CO2 concentration and isotopic composition were performed at each
mining license. Based in three different endmembers (biogenic, atmospheric and
deep-seated CO2) with different CO2 concentrations (100, 0.04 and 100%, respectively)
and isotopic compositions (-24, -8 and -3 per mil vs. VPDB respectively) a mass
balance to distinguish the different contribution of each endmember in the soil
CO2 at each sampling site was made. The percentage of the volcano-hydrothermal
contribution in the current diffuse CO2 degassing was in the range 0-19%. The Abeque
mining license, that comprises part of the north-west volcanic rift of Tenerife, seemed
to show the highest geothermal potential, with an average of 19% of CO2 being
released from deep sources, followed by Atidama (south east of Gran Canaria) and
Garehagua (southern volcanic rift of Tenerife), with 17% and 12% respectively. |
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