Hydrothermal Circulation in the Acqui Terme District, Tertiary Piedmont Basin (NW Italy)
- Key words
- Geothermal system, medium enthalpy reservoir, convective heat transfer, hot springs
- Location
- Acqui Terme, Italy
- Conference
- European Geothermal Conference
- Year
- 1999
- Session
- Hydrogeothermics
- Language
- English
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Abstract
We investigated the deep hydrothermal circulation of the Acqui Terme district, Tertiary Piedmont Basin (TPB), which is characterised by hot springs, with a maximum temperature of about 70 "C. A thermal gradient increasing from about 70 to 90 mK m'l towards the hot spring area was determined in two conduction-dominated boreholes. Calculations on convection-dominated boreholes again yielded anomalously high thermal gradients compared to those expected for TPB. The hydrothermal circulation mainly affects the crystalline basement beneath the impermeable sedimentary cover. The maximum depth of the hydrothermal system is 3400 m, and the top of the permeable zone ruled by convection is at a depth of about 1000 m. Models of ascending flow show that the water rises from the reservoir through a relatively narrow fracture zone.
Copyright 1999, Bulletin d'HydrogÈologie, Peter Lang AG, Bern, Switzerland. Readers who download papers from this site should honour the copyright of the original authors, and may not copy or distribute the work further without the permission of the original publisher.