Chiozzi, Paolo

Pasqua, Claudio

Verdoya, Massimo

English

Massimo Verdoya

Paolo Chiozzi

Claudio Pasqua

Archivio istituzionale della ricerca - Università di Genova

Geophysical Research AbstractsVol. 19, EGU2017-12474-1, 2017EGU General Assembly 2017© Author(s) 2017. CC Attribution 3.0 License.Geothermal surveys in the oceanic volcanic island of MauritiusMassimo Verdoya (1), Paolo Chiozzi (1), Claudio Pasqua (1,2)(1) Università di Genova, DISTAV, Genova, Italy, (2) ELC-Electroconsult, Milano, ItalyOceanic island chains are generally characterised by young volcanic systems that are predominately composed ofbasaltic lavas and related magmatic products. Although hot springs are occasionally present, the pervasive, mas-sive, recent outpourings of basaltic lavas are the primary manifestation of the existence of geothermal resources.These islands may have, in principle, significant potential for the exploitation of geothermal energy. In this paper,we present results of recent investigations aimed at the evaluation of geothermal resources of the island of Mau-ritius, that is the emerging portion of a huge submarine, aseismic, volcanic plateau extending in the SW part ofthe Indian Ocean. The plateau is related to a long-lived hotspot track, whose present-day expression is the activevolcano of La Réunion Island, located about 200 km SW of Mauritius. The island does not show at present anyvolcanic activity, but magmatism is quite recent as it dates from 7.8 to 0.03 Myr. Geochemical data from watersamples collected from boreholes do not indicate the presence of mature water, i.e. circulating in high-temperaturegeothermal reservoirs, and argue for short-term water-rock interaction in shallow hydrogeological circuits. How-ever, this cannot rule out that a deep magmatic heat source, hydraulically insulated from shallow aquifers, mayoccur. To evaluate the geothermal gradient, a 270-m-deep hole was thus drilled in the island central portion, inwhich the most recent volcanic activity (0.03 Myr) took place. Temperature-depth profiles, recorded after com-plete thermal equilibration, revealed a thermal gradient of 40 mK/m. Attempts of extracting additional thermalinformation were also made by measuring the temperature in a 170-m-deep deep water hole, no longer used. Theresults were consistent with the gradient hole, i.e. pointing to a weak or null deep-seated thermal anomaly beneathMauritius and low geothermal potential. The deep thermal process (mantle plume) invoked to occur in the hotspotarea thus seems to yield no particular thermal signature.

Geothermal surveys in the oceanic volcanic island of Mauritius

https://iris.unige.it/bitstream/11567/893744/1/EGU2017-12474.pdf

Geothermal surveys in the oceanic volcanic island of Mauritius

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Archivio istituzionale della ricerca - Università di Genova