Geology of the Pleistocene volcano of Monte Amiata (Southern Tuscany, Italy)

Monte Amiata (305–231 ka; Italy) is an uncommon example of an entirely effusive silicic (mainly trachytic) composite volcano. A detailed geological map (1:25,000 scale) based on Unconformity Bounded Stratigraphic Unit criteria is presented accompanied by volcano-tectonic, stratigraphic relationship, and volcano evolution schemes. The volcanic facies analysis and structural analysis criteria have been applied to decipher Monte Amiata's geological evolution and structure, and to infer the relations between volcanism and regional tectonics. Based on the occurrence of a first-order geological unconformity representing a paleo-weathering surface of paleoclimatic significance, two major volcanic stratigraphic units and seven phases of activity are recognized.