Monte Amiata volcano (Tuscany, Italy) in the history of volcanology, part 1: Its role in the debates on extinct volcanoes, sources of magma, and eruptive mechanisms (1733-1935)

A review of the main contributions to the scientific literature between the eighteenth and twentieth centuries concerning the geology and volcanology of Monte Amiata volcano (Tuscany, central Italy) is presented. Monte Amiata, and the nearby volcano of Radicofani, are of great interest for the history of volcanology because they have the primacy of being the first to be recognized of volcanic origin in a region (Tuscany) which was not volcanically active, thirty years before Guettard's studies on the Auvergne region in France. Indeed, the Florentine botanist Pier Antonio Micheli identified as extinct volcanoes Radicofani in 1722 and Monte Amiata in 1733. Moreover, the merit of Micheli's work resides in interpreting Monte Amiata as an extinct volcano despite the absence of a conventional cone-shaped volcano morphology, and in his recognizing its rocks as lavas despite their marked differences to those produced by the known active volcanoes of its times, such as the iconic Vesuvius. During the eighteenth century and until the first half of the nineteenth century, Monte Amiata was a destination for scientific journeys by Tuscan and foreign scholars (e.g. Micheli, Baldassarri, Arduino, Fortis, Ferber, Dolomieu, Santi, Repetti, Hoffmann). In addition, its rocks were part of important collections throughout Europe visited by illustrious mineralogists. Furthermore, samples from Monte Amiata were used to illustrate the general discussions on the nature and origin of rocks such as basalt and granite. In the nineteenth century, Monte Amiata was included in the lists of known volcanoes recorded in the early treatises on volcanology made by Scrope, Daubeny, and Hoffmann, and its 'trachyte' was the subject of early essays on microscope petrography and chemical analysis of rocks, performed by vom Rath, Rosenbusch, Williams, Lacroix, and Washington. Between the end of the nineteenth century and the first quarter of the twentieth century, the volcano geologists of the Comitato Geologico Italiano, especially Verri, Lotti, and Sabatini, carried out field-surveys on Monte Amiata resulting in geological maps and volcano-stratigraphies. Moreover, modern petrographic (Novarese, Artini, Rodolico) and geographical (Dainelli and Olinto Marinelli) scientific studies were carried out on this volcano. Nevertheless, up to the middle part of the twentieth century, the major interest in Monte Amiata was related not to its volcanological aspects but to its natural resources: drinking waters, diatomaceous earths, earth pigments, and mercury ore-minerals.