Precedenti studi vulcanologici sul Monte Amiata

This Chapter presents a review of the main works in the scientific literature on the geology and volcanology of Monte Amiata. After the first recognition of the volcanic nature of Monte Amiata made by Micheli in 1733, between the end of the 17th and the 19th centuries, there were numerous reports of naturalistic travels carried out in this territory and descriptions of its rocks. Modern scientific studies, essentially of petrographical (Lotti, 1932, Rodolico, 1935) and geographical (Dainelli, 1910; Marinelli, 1919) characters, were carried out from the twentieth century. From the 1950s to 1970s, the volcanology of Monte Amiata is marked by the ideas of two great names of Italian volcanology: Alfred Rittmann and Giorgio Marinelli. Rittmann (1958) introduced the term "rheomorphic ignimbrite" to describe the extensive sheet of glassy volcanic rocks that seem to form a single body at the base of the volcanic edifice. Its interpretation is that the large mass of volcanics at the base of Amiata would be the result of the repeated emplacement of pyroclastic flows emitted by a linear fracture and in their entirety constituting a sheet of rheomorphic ignimbrite erupted from a deep laccolithic structure. Marinelli (1961) essentially shared this interpretation. The authority of these two scholars made that all the following volcanological studies and geological mapping of Monte Amiata adopted their volcanological interpretation for the genesis of acidic lavas and the stratigraphic subdivision into three units. This tri-fold division of the volcanic activity of Monte Amiata includes (Ferrari et al., 1996; Marroni et al., 2015): (1) a Basal Trachydacitic Complex (BTC), in turn divided into a lower unit and a upper unit; (2) a Complex of lava domes and flows (DLC), which groups all the domes that make up the summit of the volcano and some lesser lava flows; and (3) the two basic lava flows of Macinaie and Ermeta. The review of the scientific literature on the Monte Amiata volcano has highlighted the gaps and inaccuracies contained in the past interpretations, as well as numerous insights of investigation and discussion that have been a stimulus for the mass of stratigraphic, geological and petrochemical data collected by the research work carried out for the Tuscany Region project presented in this Volume.