Crustal models of the geothermal areas of Larderello and Mt. Amiata.

The study of core samples and geophysical data from the Larderello and Mt. Amiata geothermal areas indicate the presence of granite intrusions and granitic dykes as old as 3.8-2.9 My and widespread contact aureoles. Reflection seismic surveys reveal the presence of a highly reflective horizon (named K) in a depth range of 3-12 km in the two geothermal areas; seismic tomography and teleseismic studies show at Larderello a low velocity body, 30-40 km wide below the K horizon. Magnetotelluric surveys indicate the presence of a conductive body in good correlation with the anomalous tomographic and teleseismic body. The occurrence of shallow intrusive bodies, still partilally molten and associated with saline brines is here considered a reliable model