Relationships between geological structures and geothermal resources in southern Tuscany

Southern Tuscany is located in the inner part of the Northern Apennines, an area which experienced lithospheric thickening, during the Cretaceous-Early Miocene, and lithospheric thinning, during Miocene - Present. From Messinian, extension was accompanied by widespread middle crustal plutonism and volcanism. The interplay among extensional structures, cooling of magmas, and meteoric waters, determined the conditions for a significant hydrothermal fluid flow, leading to widespread Pliocene-Pleistocene ore deposits. Today southern Tuscany is characterized by heat flow of about 120mW/m2, on average, with local picks up to 1000 and 600 mW/m2, in the Larderello and Monte Amiata, geothermal fields, respectively. The maintenance of the tectonic setting and geological evolution since Messinian makes southern Tuscany an unique area for bridging the past and the present geothermal activity and therefore for improving our knowledge on the relationships between geological structures and geothermal resources.