L'andamento morfo-strutturale del substrato del Monte Amiata

In this Chapter, we present the results of the stratigraphic review on a data-set of 66 boreholes drilled into the Monte Amiata volcanic edifice, including 5 recently drilled deep-wells. The purpose of this review was to obtain a reliable database for the reconstruction of the morpho-structural surface of the Monte Amiata substratum. The map elaborated confirms the presence of a 15 km2 depression in the south-western portion, and a morphological high in the north-eastern portion of the volcanic edifice. The same morphological features, with less detail and some dimension differences, were have been identified by all previous studies and variously interpreted. The morpho-structural analysis carried out in this Chapter leads to the exclusion of this depression because of purely erosive phenomena or pre-volcanics, as claimed by the previous authors. Our results are: (i) a better definition of the morphology of the substratum depression in the south-western part of the volcano, and (ii) the interpretation of the origin of this depression as possibly linked both to the transtensive tectonic system that has been active over the last 300 ka and to Monte Amiata volcanism.