The Marsili Volcanic Seamount (Southern Tyrrhenian Sea): A Potential Offshore Geothermal Resource

Abstract

Italy has a strong geothermal potential for power generation, although, at present, the only two geothermal fields being exploited are Larderello-Travale/Radicondoli and Mt. Amiata in the Tyrrhenian pre-Apennine volcanic district of Southern Tuscany. A new target for geothermal exploration and exploitation in Italy is represented by the Southern Tyrrhenian submarine volcanic district, a geologically young basin (Upper Pliocene-Pleistocene) characterised by tectonic extension where many seamounts have developed. Heat-flow data from that area show significant anomalies comparable to those of onshore geothermal fields. Fractured basaltic rocks facilitate seawater infiltration and circulation of hot water chemically altered by rock/water interactions, as shown by the widespread presence of hydrothermal deposits. The persistence of active hydrothermal activity is consistently shown by many different sources of evidence, including: heat-flow data, gravity and magnetic anomalies, widespread presence of hydrothermal-derived gases (CO 2 , CO, CH 4 ), 3 He/ 4 He isotopic ratios, as well as broadband OBS/H seismological information, which demonstrates persistence of volcano-tectonic events and High Frequency Tremor (HFT). The Marsili and Tyrrhenian seamounts are thus an important-and likely long-lasting-renewable energy resource. This raises the possibility of future development of the world's first offshore geothermal power plant. OPEN ACCESSEnergies 2014, 7 4069

Evidence of a shallow water submarine hydrothermal field off Zannone Island from morphological and geochemical characterization: Implications for Tyrrhenian Sea Quaternary volcanism

“…The dashed black line indicates a trend of CO 2 injection in an ASSW. Blue triangles = dissolved gases from Pontine Island with sample ID labeled as in Table ; black crosses = samples from Marsili seamount [after Italiano et al ., ]; grey‐filled circles = samples from Capo Vaticano seamount [after Loreto et al ., ]. The numbers in italics = Marsili samples depths.…”

“…Offshore, CO 2 ‐rich gas emissions (Table ) are known to occur in shallow water around the Ischia Island coastal zone [ Maugeri et al ., ], in the Bay of Naples [ Passaro et al ., ; Passaro et al ., ], offshore Capo Vaticano [ Loreto et al ., , ], and throughout the Aeolian Archipelago [ Italiano , ; Maugeri et al ., ; Monecke et al ., ; Graziani et al ., ]. Deep‐sea hydrothermal activity, highlighted by 3 He and dissolved CO 2 anomalies, is reported at almost all the Tyrrhenian seamounts [ Lupton et al ., ; Walker et al ., ; Italiano et al ., ]. H 2 S‐rich gas emissions are also present [ Stüben et al ., ; Rovere et al ., ].…”

Observing Volcanoes from the Seafloor in the Central Mediterranean Area

“…Geophysical and morphological observations point to hydrothermal activity in the MS linked to the post volcanic activity [62][63][64]. The possible existence of a very large underwater explosive volcano together with some encouraging clues that point to MS as an important and possible long-lasting-renewable energy resource [65] has reinforced research and exploitation efforts. The existence of an active magmatic chamber at about 2.5 km below the summit was proposed on the basis of petrological studies of basalts [66], and it is compatible with gravimetric and magnetic data modeling [62], as well as geochemical observations on the summit [67].…”

Geothermal Energy: Delivering on the Global Potential

“…The case of Chile offers a compelling worked example of how such an approach can be used to estimate future energy productivity for individual fields, and thence for an entire country in which no geothermal power plant has yet been developed [32]. Already, consideration is being given to developments even further into the future, when geothermal developments might follow the historical precedent of hydrocarbons and progress to offshore exploitation of submarine hydrothermal circulation systems, such as those associated with the Marsili Seamount in the southern Tyrrhenian Sea (Italy) [33] or with sea-floor spreading ridges off the northwestern coast of the USA [34].…”